HomeMy WebLinkAboutSDP 15-23; NORTH COAST MEDICAL PLAZA; STORM WATER QUALITY MANAGEMENT PLAN; 2025-06-04
CITY OF CARLSBAD
PRIORITY DEVELOPMENT PROJECT (PDP)
STORM WATER QUALITY MANAGEMENT PLAN (SWQMP) FOR
North Coast Medical Plaza Phase I & II
PROJECT ID SDP 15-23/ CDP 15-43
SWQMP # GR2022-0050
DWG # 496-1B
ENGINEER OF WORK:
Robert D. Dentino, PE RCE 45629 Exp. 12/31/20
PREPARED FOR:
SSG TH, LLC
CBRE
4365 EXECUTIVE DRIVE # 1600
SAN DIEGO, CA 92121
PREPARED BY:
EXCEL ENGINEERING
440 State Place,
Escondido, CA, 92029
(760)745-8118
DATE PREPARED:
MARCH 30, 2023
PREVIOUS SUBMITTALS:
DECEMBER 15, 2022
TABLE OF CONTENTS
Certification Page
Project Vicinity Map
FORM E-34 Storm Water Standard Questionnaire
Site Information
FORM E-36 Standard Project Requirement Checklist
Summary of PDP Structural BMPs
Attachment 1: Backup for PDP Pollutant Control BMPs
Attachment 1a: DMA Exhibit
Attachment 1b: Tabular Summary of DMAs and Design Capture Volume Calculations
Attachment 1c: Harvest and Use Feasibility Screening (when applicable)
Attachment 1d: Categorization of Infiltration Feasibility Condition (when applicable)
Attachment 1e: Pollutant Control BMP Design Worksheets / Calculations
Attachment 1f: Trash Capture BMP Requirements
Attachment 2: Backup for PDP Hydromodification Control Measures
Attachment 2a: Hydromodification Management Exhibit
Attachment 2b: Management of Critical Coarse Sediment Yield Areas
Attachment 2c: Geomorphic Assessment of Receiving Channels
Attachment 2d: Flow Control Facility Design
Attachment 3: Structural BMP Maintenance Thresholds and Actions
Attachment 4: Single Sheet BMP (SSBMP) Exhibit
CERTIFICATION PAGE
North Coast Medical Plaza Phase I & II
Project ID: SDP 15-23/ CDP 15-43
I hereby declare that I am the Engineer in Responsible Charge of design of storm water BMPs
for this project, and that I have exercised responsible charge over the design of the project as
defined in Section 6703 of the Business and Professions Code, and that the design is consistent
with the requirements of the BMP Design Manual, which is based on the requirements of
SDRWQCB Order No. R9-2013-0001 (MS4 Permit) or the current Order.
I have read and understand that the City Engineer has adopted minimum requirements for
managing urban runoff, including storm water, from land development activities, as described in
the BMP Design Manual. I certify that this SWQMP has been completed to the best of my ability
and accurately reflects the project being proposed and the applicable source control and site
design BMPs proposed to minimize the potentially negative impacts of this project's land
development activities on water quality. I understand and acknowledge that the plan check
review of this SWQMP by the City Engineer is confined to a review and does not relieve me, as
the Engineer in Responsible Charge of design of storm water BMPs for this project, of my
responsibilities for project design.
Engineer of Work's Signature, PE Number & Expiration Date
Print Name
Company
03/30/2023
Date
RCE 45629/ EXP. 12-31-20
ROBERT D. DENTINO
EXCEL ENGINEERING
PROJECT VICINITY MAP
VICINITY
CITY OF' OCEANSIDE
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CITY OF ENCINITAS
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CITY OF' VISTA
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SAN MARCOS
STORM WATER STANDARDS QUESTIONNAIRE
E-34
Development Services
Land Development Engineering
1635 Faraday Avenue
442-339-2750
www.carlsbadca.gov
To address post-development pollutants that may be generated from development projects, the city requires that new development and significant redevelopment priority projects incorporate Permanent Storm Water Best Management Practices (BMPs) into the project design per Carlsbad BMP Design Manual (BMP Manual). To view the BMP Manual, refer
to the Engineering Standards (Volume 5).
This questionnaire must be completed by the applicant in advance of submitting for a development application (subdivision,
discretionary permits and/or construction permits). The results of the questionnaire determine the level of storm water standards that must be applied to a proposed development or redevelopment project. Depending on the outcome, your
project will either be subject to ‘STANDARD PROJECT’ requirements, “PRIORITY DEVELOPMENT PROJECT (PDP) requirements or not considered a development project. This questionnaire will also determine if the project is subject to TRASH CAPTURE REQUIREMENTS.
Your responses to the questionnaire represent an initial assessment of the proposed project conditions and impacts. City staff has responsibility for making the final assessment after submission of the development application. If staff determines that the questionnaire was incorrectly filled out and is subject to more stringent storm water standards than initially assessed by you, this will result in the return of the development application as incomplete. In this case, please make the changes to the questionnaire and resubmit to the city.
If you are unsure about the meaning of a question or need help in determining how to respond to one or more of the questions, please seek assistance from Land Development Engineering staff.
A completed and signed questionnaire must be submitted with each development project application. Only one completed and signed questionnaire is required when multiple development applications for the same project are submitted concurrently. PROJECT INFORMATION
PROJECT NAME: APN:
ADDRESS:
The project is (check one): New Development Redevelopment
The total proposed disturbed area is: ft2 ( ) acres
The total proposed newly created and/or replaced impervious area is: ft2 ( ) acres
If your project is covered by an approved SWQMP as part of a larger development project, provide the project ID and the SWQMP # of the larger development project:
Project ID SWQMP #:
Then, go to Step 1 and follow the instructions. When completed, sign the form at the end and submit this with your application to the city.
This Box for City Use Only
City Concurrence:
YES NO Date: Project ID:
By:
E-34 Page 1 of 4 REV 08/22
INSTRUCTIONS:
C cityof
Carlsbad
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E-34 Page 2 of 4 REV 08/22
STEP 1 TO BE COMPLETED FOR ALL PROJECTS
To determine if your project is a “development project”, please answer the following question: YES NO
Is your project LIMITED TO routine maintenance activity and/or repair/improvements to an existing building or structure that do not alter the size (See Section 1.3 of the BMP Design Manual for guidance)?
If you answered “yes” to the above question, provide justification below then go to Step 6, mark the box stating “my project is not a ‘development project’ and not subject to the requirements of the BMP manual” and complete applicant information.
Justification/discussion: (e.g. the project includes only interior remodels within an existing building): If you answered “no” to the above question, the project is a ‘development project’, go to Step 2.
STEP 2 TO BE COMPLETED FOR ALL DEVELOPMENT PROJECTS
To determine if your project is exempt from PDP requirements pursuant to MS4 Permit Provision E.3.b.(3), please answer the following questions:
Is your project LIMITED to one or more of the following: YES NO
1. Constructing new or retrofitting paved sidewalks, bicycle lanes or trails that meet the following criteria: a) Designed and constructed to direct storm water runoff to adjacent vegetated areas, or other non- erodible permeable areas; OR b) Designed and constructed to be hydraulically disconnected from paved streets or roads; OR c) Designed and constructed with permeable pavements or surfaces in accordance with USEPA Green Streets guidance?
2. Retrofitting or redeveloping existing paved alleys, streets, or roads that are designed and constructed in accordance with the USEPA Green Streets guidance?
3. Ground Mounted Solar Array that meets the criteria provided in section 1.4.2 of the BMP manual?
If you answered “yes” to one or more of the above questions, provide discussion/justification below, then go to Step 6, mark the second box stating “my project is EXEMPT from PDP …” and complete applicant information.
Discussion to justify exemption (e.g. the project redeveloping existing road designed and constructed in accordance with the USEPA Green Street guidance):
If you answered “no” to the above questions, your project is not exempt from PDP, go to Step 3.
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E-34 Page 3 of 4 REV 08/22
STEP 3 TO BE COMPLETED FOR ALL NEW OR REDEVELOPMENT PROJECTS
To determine if your project is a PDP, please answer the following questions (MS4 Permit Provision E.3.b.(1)): YES NO
1. Is your project a new development that creates 10,000 square feet or more of impervious surfaces collectively over the entire project site? This includes commercial, industrial, residential, mixed-use, and public development projects on public or private land.
2. Is your project a redevelopment project creating and/or replacing 5,000 square feet or more of impervious surface collectively over the entire project site on an existing site of 10,000 square feet or more of impervious surface? This includes commercial, industrial, residential, mixed-use, and public development projects on public or private land.
3. Is your project a new or redevelopment project that creates and/or replaces 5,000 square feet or more of impervious surface collectively over the entire project site and supports a restaurant? A restaurant is a
facility that sells prepared foods and drinks for consumption, including stationary lunch counters and refreshment stands selling prepared foods and drinks for immediate consumption (Standard Industrial Classification (SIC) code 5812).
4. Is your project a new or redevelopment project that creates 5,000 square feet or more of impervious
surface collectively over the entire project site and supports a hillside development project? A hillside development project includes development on any natural slope that is twenty-five percent or greater.
5. Is your project a new or redevelopment project that creates and/or replaces 5,000 square feet or more of impervious surface collectively over the entire project site and supports a parking lot? A parking lot is a
land area or facility for the temporary parking or storage of motor vehicles used personally for business or for commerce.
6. Is your project a new or redevelopment project that creates and/or replaces 5,000 square feet or more of impervious street, road, highway, freeway or driveway surface collectively over the entire project site? A street, road, highway, freeway or driveway is any paved impervious surface used for the transportation of automobiles, trucks, motorcycles, and other vehicles.
7. Is your project a new or redevelopment project that creates and/or replaces 2,500 square feet or more of impervious surface collectively over the entire site, and discharges directly to an Environmentally Sensitive Area (ESA)? “Discharging Directly to” includes flow that is conveyed overland a distance of 200 feet or less from the project to the ESA, or conveyed in a pipe or open channel any distance as an isolated flow from the project to the ESA (i.e. not commingled with flows from adjacent lands).*
8. Is your project a new development or redevelopment project that creates and/or replaces 5,000 square feet or more of impervious surface that supports an automotive repair shop? An automotive repair shop is a facility that is categorized in any one of the following Standard Industrial Classification (SIC) codes: 5013, 5014, 5541, 7532-7534, or 7536-7539.
9. Is your project a new development or redevelopment project that creates and/or replaces 5,000 square feet or more of impervious area that supports a retail gasoline outlet (RGO)? This category includes
RGO’s that meet the following criteria: (a) 5,000 square feet or more or (b) a project Average Daily Traffic (ADT) of 100 or more vehicles per day.
10. Is your project a new or redevelopment project that results in the disturbance of one or more acres of land and are expected to generate pollutants post construction?
11. Is your project located within 200 feet of the Pacific Ocean and (1) creates 2,500 square feet or more of impervious surface or (2) increases impervious surface on the property by more than 10%? (CMC
21.203.040)
If you answered “yes” to one or more of the above questions, your project is a PDP. If your project is a redevelopment
project, go to step 4. If your project is a new project, go to step 5, complete the trash capture question.
If you answered “no” to all of the above questions, your project is a ‘STANDARD PROJECT’. Go to step 5, complete the trash capture question.
* Environmentally Sensitive Areas include but are not limited to all Clean Water Act Section 303(d) impaired water bodies; areas designated as Areas of Special Biological Significance by the State Water Resources Control Board (Water Quality Control Plan for the San Diego Basin (1994) and amendments); water bodies designated with the RARE beneficial use by the State Water Resources Control Board (Water Quality Control Plan for the San Diego Basin (1994) and amendments); areas designated as preserves or their equivalent under the Multi Species Conservation Program within the Cities and County of San Diego; Habitat Management Plan; and any other equivalent environmentally sensitive areas which have been identified by the City.
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E-34 Page 4 of 4 REV 08/22
STEP 4 TO BE COMPLETED FOR REDEVELOPMENT PROJECTS THAT ARE PRIORITY DEVELOPMENT PROJECTS (PDP) ONLY Complete the questions below regarding your redevelopment project (MS4 Permit Provision E.3.b.(2)): YES NO
Does the redevelopment project result in the creation or replacement of impervious surface in an amount of less than 50% of the surface area of the previously existing development? Complete the percent impervious calculation below:
Existing impervious area (A) = sq. ft.
Total proposed newly created or replaced impervious area (B) = sq. ft.
Percent impervious area created or replaced (B/A)*100 = %
If you answered “yes”, the structural BMPs required for PDP apply only to the creation or replacement of impervious surface
and not the entire development. Go to step 5, complete the trash capture question.
If you answered “no,” the structural BMP’s required for PDP apply to the entire development. Go to step 5, complete the trash capture question.
STEP 5 TO BE COMPLETED FOR ALL DEVELOPMENT PROJECTS
Complete the question below regarding your Project (SDRWQCB Order No. 2017-0077):
YES NO
Is the Project within any of the following Priority Land Use (PLU) categories and not exempt from trash capture requirements per section 4.4.2.2 of the BMP Manual?
R-23 (15-23 du/ac), R-30 (23-30 du/ac), PI (Planned Industrial), CF (Community Facilities), GC (General Commercial), L (Local Shopping Center), R (Regional Commercial), V-B (Village-Barrio), VC (Visitor Commercial), O (Office), VC/OS (Visitor Commercial/Open Space), PI/O (Planned Industrial/Office), or Public Transportation Station
If you answered “yes”, the ‘PROJECT’ is subject to TRASH CAPTURE REQUIREMENTS. Go to step 6, check the first box stating, “My project is subject to TRASH CAPTURE REQUIREMENTS …” and the second or third box as determined in step 3.
If you answered “no”, Go to step 6, check the second or third box as determined in step 3. List exemption if applicable for ‘no’ answer here:
STEP 6 CHECK THE APPROPRIATE BOX(ES) AND COMPLETE APPLICANT INFORMATION
My project is subject to TRASH CAPTURE REQUIREMENTS and must comply with TRASH CAPTURE REQUIREMENTS of the BMP Manual. I understand I must prepare a Storm Water Quality Management Plan (SWQMP).
My project is a ‘STANDARD PROJECT’ OR EXEMPT from PDP and must only comply with ‘STANDARD PROJECT’ stormwater requirements of the BMP Manual. I will submit a “Standard Project Requirement Checklist Form E-36”. If my project is subject to TRASH CAPTURE REQUIREMENTS, I will submit a TRASH CAPTURE Storm Water Quality Management Plan (TCSWQMP) per E-35A.
My project is a PDP and must comply with PDP stormwater requirements of the BMP Manual. I understand I must prepare a Storm Water Quality Management Plan (SWQMP) per E-35 template for submittal at time of application.
Note: For projects that are close to meeting the PDP threshold, staff may require detailed impervious area calculations and exhibits to verify if ‘STANDARD PROJECT’ stormwater requirements apply.
My project is NOT a ‘development project’ and is not subject to the requirements of the BMP Manual. Applicant Information and Signature Box
Applicant Name: Applicant Title:
Applicant Signature: Date:
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SITE INFORMATION CHECKLIST
Project Summary Information
Project Name North Coast Medical Plaza Phase I & II
Project ID SDP 15-23/CDP 15-43
Project Address 6020 Hidden Valley Road
Carlsbad, CA 92011
Assessor's Parcel Number(s) (APN(s)) 212-040-67, 212-040-68 , 212-040-69
Project Watershed (Hydrologic Unit) Carlsbad 904
Parcel Area
6.77 Acres
( 294,901 Square Feet)
Existing Impervious Area
(subset of Parcel Area)
3.06 Acres
( 133,294 Square Feet)
Area to be disturbed by the project
(Project Area)
2.31 Acres
( 100,579 Square Feet)
Project Proposed Impervious Area
(subset of Project Area)
1.91 Acres
( 83,182 Square Feet)
Project Proposed Pervious Area
(subset of Project Area)
0.40 Acres
( 17,397 Square Feet)
Note: Proposed Impervious Area + Proposed Pervious Area = Area to be Disturbed by the
Project.
This may be less than the Parcel Area.
Description of Existing Site Condition and Drainage Patterns
Current Status of the Site (select all that apply):
Existing development
Previously graded but not built out
Agricultural or other non-impervious use
Vacant, undeveloped/natural
Description/Additional Information:
The existing site includes a previously built medical office building and parking area (as part of
Phase I) and a rough graded vacant pad.
Existing Land Cover Includes (select all that apply):
Vegetative Cover
Non-Vegetated Pervious Areas
Impervious Areas
Description / Additional Information:
of the impervious area
Description / Additional Information:
The site is currently a rough graded pad being served by the existing improvements installed as
part of the Kelly Corporate Center – Phase I (City of Carlsbad approved Drawing No. 381-6 and
381-6A) and west between Hidden Valley Road and Aviara Parkway. The graded pad has
existing parking and drive aisles abutting it to the west and the south, and it is also served by
utilities (sewer, water, storm drain, and dry utilities). Drainage flows to both the south, southwest,
and the northwest to existing curb inlets located across the westerly drive aisle in islands
adjacent to the Phase I medical office building and to an existing curb inlet located at the
southwest corner of the existing parking lot of the existing building.
Once collected in these curb inlets, the runoff flows through existing storm drainage pipes
running westerly to the south and north of the existing building towards an existing storm drain
main line run at the western property line that directs the combined flows of the entire site to the
south. This main line run begins at the northwest corner of the property where it picks up a
drainage swale (installed as part of Drawing No. 381-6A) located in a 50’-wide drainage
easement immediately north of the parking areas and south of Palomar Airport Road. This
collected flow is directed southerly and combines with the on-site flows, and connects to a series
of box culverts that cross Hidden Valley Road as part of the Encinas Creek drainage path. Once
in Encinas Creek, the flows are directed along the south side of Palomar Airport Road and enter
the Pacific Ocean at South Carlsbad State Beach. This represents the Carlsbad Hydrologic Unit,
Encinas HA (904.40).
Underlying Soil belongs to Hydrologic Soil Group (select all that apply):
NRCS Type A
NRCS Type B
NRCS Type C
NRCS Type D
Approximate Depth to Groundwater (GW):
GW Depth < 5 feet
5 feet < GW Depth < 10 feet
10 feet < GW Depth < 20 feet
GW Depth > 20 feet
Existing Natural Hydrologic Features (select all that apply):
Watercourses
Seeps
Springs
Wetlands
None
Description / Additional Information:
The existing natural hydrologic features is divided by two halves, with the northern half of the
property draining to the north and the southern half of the property draining to the south. The
northern half of the site surface flows to an existing curb inlet on the north side of the property
which is routed to an existing storm drain system that discharges to the public earthen drainage
channel to the west. The south half of the property surface flows to an existing curb inlet on the
south side of the property which is routed to an existing storm drain system that discharges to the
public earthen drainage channel to the west. The drainage channel flows in a westerly direction
paralleling Palomar Airport Road. The channel ends approximately 350 feet from the project site
in a concrete lined detention structure located near the south easterly corner of the intersection
between Palomar Airport Road and Hidden Valley Road which then drains into Encinas Creek
and then ultimately the Pacific Ocean.
V
Description of Existing Site Topography and Drainage [How is storm water runoff conveyed from
the site? At a minimum, this description should answer (1) whether existing drainage
conveyance is natural or urban; (2) describe existing constructed storm water conveyance
systems, if applicable; and (3) is runoff from offsite conveyed through the site? if so, describe]:
The existing site topography is a graded flat pad located on a property that currently consists of a
vacant lot situated directly between a medical plaza to the west and a bank to east, southeast of
the intersection of Palomar Airport Road and Hidden Valley Road in Carlsbad. The existing pad
slopes gently to the north at 1%-2%. The direction of flow is divided by two; the half portion of the
property drains to north and the other portion drains to south. Both of these natural surface flows
are captured by two existing inlets and then drain to a public drainage system before being
released to a public drainage system (earthen channel) located at southwest corner of the site.
The existing impervious (urban) improvements on the site constructed per Phase I surface flows
to the aforementioned inlets and channel. The earthen channel flows in a westerly direction
paralleling Palomar Airport Road. The channel ends approximately 350 feet from the project site in
a concrete lined detention structure located near the south easterly corner of the intersection
between Palomar Airport Road and Hidden Valley Road. From there, after drainage leaves the
site, it combines with Encinas Creek and flows to the west where it discharges into the Pacific
Ocean south of Palomar Airport Road at South Carlsbad State Beach. No runoff from offsite is
conveyed though the project site.
Description of Proposed Site Development and Drainage Patterns
Project Description / Proposed Land Use and/or Activities:
The project proposes the construction of a 50,000 square foot, two-story office building located on the south
side of Palomar Airport Road between Hidden Valley Road and Aviara Parkway. The project site is
generally located adjacent to and on the south side of Palomar Airport Road between Hidden Valley Road
and Aviara Parkway. The project is part of the Kelly Corporate Center development. Phase I and Phase II
project area consists of two areas of construction. Phase I project area proposes to re-grade the existing
entry, removal of circular entrance to existing building in the phase I, construct Biofiltration pond, re-
striping the existing parking lot to allow additional compact parking spaces. Phase II proposes to install a
single medical office building, parking area and stormdrain system. The development was originally
approved for the construction of four (4) two-story multi-tenant office buildings. This project proposes to
construct the fourth and final building on this site. The proposed building is a generally mirrored image of
the existing building 2a property building is on Parcel 3 and the existing building is on Parcel 2. The project
includes the construction of a new building with associated parking and drive isle facilities, landscaping and
integrated stormwater treatment facilities on an existing graded lot.
List/describe proposed impervious features of the project (e.g., buildings, roadways, parking
lots, courtyards, athletic courts, other impervious features):
The proposed impervious features of the project include the building roof area, the majority
of the parking area pavement, outdoor patios and pedestrian walkways.
List/describe proposed pervious features of the project (e.g., landscape areas):
The proposed pervious areas of the site include the landscaped areas and the biofiltration
basins.
Does the project include grading and changes to site topography?
Yes
No
Description / Additional Information:
The existing site topography is already a graded flat pad and the pad slopes gently to the north at
1%-2%. Site topography does not change much.
The portion at Southwest of the phase I is regraded to drain new driveway entry configuration
toward a new BMP and treating what was previously untreated impervious while other areas on
Phase I are just resurfaced with the same drainage patterns.
V
Does the project include changes to site drainage (e.g., installation of new storm water
conveyance systems)?
Yes
No
Description / Additional Information:
Phase I drainage pattern & infrastructure remains unchanged except for the routine of a portion
of untreated driveway through BMP F.
The current drainage pattern of Phase II is generally described as overland sheet flow in a
northerly direction. The proposed drainage patterns will be to direct the surface runoff to each of
three biofiltration areas where the runoff will be stored, filtered and released to the existing
drainage course along the northerly and southerly boundary of the site.
The POC for both phases remains the same for both existing and ultimate conditions. No
diversion is proposed.
V
Identify whether any of the following features, activities, and/or pollutant source areas will be
present (select all that apply):
On-site storm drain inlets
Interior floor drains and elevator shaft sump pumps
Interior parking garages
Need for future indoor & structural pest control
Landscape/Outdoor Pesticide Use
Pools, spas, ponds, decorative fountains, and other water features
Food service
Refuse areas
Industrial processes
Outdoor storage of equipment or materials
Vehicle and Equipment Cleaning
Vehicle/Equipment Repair and Maintenance
Fuel Dispensing Areas
Loading Docks
Fire Sprinkler Test Water
Miscellaneous Drain or Wash Water
Plazas, sidewalks, and parking lots
V
V
Identification of Receiving Water Pollutants of Concern
Describe path of storm water from the project site to the Pacific Ocean (or bay, lagoon, lake or
reservoir, as applicable):
The project is located in the Canyon de las Encinas watershed, Carlsbad Hydrologic Unit (904).
The project discharges directly to an unlined drainage channel that parallels the southwestern side
of the project site. The flow path follows a natural water course to the Pacific Ocean
approximately 1.4 miles from the site. The natural water course is Encinas Creek.
List any 303(d) impaired water bodies within the path of storm water from the project site to the
Pacific Ocean (or bay, lagoon, lake or reservoir, as applicable), identify the
pollutant(s)/stressor(s) causing impairment, and identify any TMDLs for the impaired water
bodies:
303(d) Impaired Water Body Pollutant(s)lStressor(s) TMDLs
ENCINAS CREEK BENTHIC COMMUNITY EFFECTS 2025
ENCINAS CREEK INDICATOR BACTERIA 2033
ENCINAS CREEK NITROGEN 2033
ENCINAS CREEK PHOSPHORUS 2019
ENCINAS CREEK SELENIUM 2019
ENCINAS CREEK TOXICITY 2019
Identification of Project Site Pollutants
Identify pollutants anticipated from the project site based on all proposed use(s) of the site (see
Table B.6-1 below):
Pollutant
Not Applicable to
the Project Site
Anticipated from the
Project Site
Also a Receiving
Water Pollutant of
Concern
Sediment X X
Nutrients X
Heavy Metals X
Organic Compounds X X
Trash & Debris X X
Oxygen Demanding
Substances X X
Oil & Grease X X
Bacteria & Viruses X
Pesticides X X
V
~ V
v-' V
v,'
~
V
v,'
V V
V
TABLE B.6-1. Anticipated and Potential Pollutants Generated by Land Use Type
Priority
Project
Categories
General Pollutant Categories
Sediment
Nutrients
Heavy
Metals
Organic
Compounds
Trash &
Debris
Oxygen
Demanding
Substances
Oil &
Grease
Bacteria &
Viruses
Pesticides
Detached
Residential
Development
Attached
Residential
Development
Commercial
Development
>one acre
P(1)
P(1)
X
P(2)
X
P(5)
X
P(5)
Heavy
Industry
Automotive
Repair Shops
Restaurants
Hillside
Development
>5,000 ft2
Parking Lots P(1)
P(1)
X
X
P(1) X
P(1)
Retail
Gasoline
Outlets
Streets,
Highways &
Freeways
X = anticipated
P = potential
(1) A potential pollutant if landscaping exists onsite.
(2) A potential pollutant if the project includes uncovered parking areas.
(3) A potential pollutant if land use involves food or animal waste products.
(4) Including petroleum hydrocarbons.
(5) Including solvents.
Hydromodification Management Requirements
Do hydromodification management requirements apply (see Section 1.6 of the BMP Design
Manual)?
Yes, hydromodification management flow control structural BMPs required.
No, the project will discharge runoff directly to existing underground storm drains discharging
directly to water storage reservoirs, lakes, enclosed embayments, or the Pacific Ocean.
No, the project will discharge runoff directly to conveyance channels whose bed and bank are
concrete-lined all the way from the point of discharge to water storage reservoirs, lakes,
enclosed embayments, or the Pacific Ocean.
No, the project will discharge runoff directly to an area identified as appropriate for an
exemption by the WMAA for the watershed in which the project resides.
Description / Additional Information (to be provided if a 'No' answer has been selected above):
Critical Coarse Sediment Yield Areas*
*This Section only required if hydromodification management requirements apply
Based on the maps provided within the WMAA, do potential critical coarse sediment yield areas
exist within the project drainage boundaries?
Yes
No, No critical coarse sediment yield areas to be protected based on WMAA maps
If yes, have any of the optional analyses presented in Section 6.2 of the BMP Design Manual
been performed?
6.2.1 Verification of Geomorphic Landscape Units (GLUs) Onsite
6.2.2 Downstream Systems Sensitivity to Coarse Sediment
6.2.3 Optional Additional Analysis of Potential Critical Coarse Sediment Yield Areas Onsite
No optional analyses performed, the project will avoid critical coarse sediment yield areas
identified based on WMAA maps
If optional analyses were performed, what is the final result?
No critical coarse sediment yield areas to be protected based on verification of GLUs onsite
Critical coarse sediment yield areas exist but additional analysis has determined that
protection is not required. Documentation attached in Attachment 8 of the SWQMP.
Critical coarse sediment yield areas exist and require protection. The project will implement
management measures described in Sections 6.2.4 and 6.2.5 as applicable, and the areas
are identified on the SWQMP Exhibit.
Discussion / Additional Information:
V
V
Flow Control for Post-Project Runoff*
*This Section only required if hydromodification management requirements apply
List and describe point(s) of compliance (POCs) for flow control for hydromodification
management (see Section 6.3.1). For each POC, provide a POC identification name or number
correlating to the project's HMP Exhibit and a receiving channel identification name or number
correlating to the project's HMP Exhibit.
There is only one Point of Compliance for this project that discharges directly to an unlined
drainage channel that parallels the southwestern side of the project site. The flow path follows a
natural water course to the Pacific Ocean approximately 1.4 miles from the site. The natural water
course is Encinas creek and is not listed on the 303d list as having any impairments to water
quality. The POC is named “Point of Compliance” and is indicated on the DMA maps as such.
Has a geomorphic assessment been performed for the receiving channel(s)?
No, the low flow threshold is 0.1Q2 (default low flow threshold)
Yes, the result is the low flow threshold is 0.1Q2
Yes, the result is the low flow threshold is 0.3Q2
Yes, the result is the low flow threshold is 0.5Q2
If a geomorphic assessment has been performed, provide title, date, and preparer:
Discussion / Additional Information: (optional)
V
Other Site Requirements and Constraints
When applicable, list other site requirements or constraints that will influence storm water
management design, such as zoning requirements including setbacks and open space, or City
codes governing minimum street width, sidewalk construction, allowable pavement types, and
drainage requirements.
The existing site has been raised with fill about 10 to 20 feet from the native soil, therefore the
infiltration rate of the soil is very low. Some of the BMPs will be required to be placed next to the
building footprint, some other BMPs are not adjacent to building. However, the soil engineer’s
recommendation is provide impervious liner underneath the biofilter regardless the location of
the BMP. Please see the Geotechnical evaluation Report by Partner dated September 9, 2022.
The overall site hydrologic soil type is “C”. From the geotechnical report for both the pre and
post development conditions the site soil has been designated as soil type “C”.
Optional Additional Information or Continuation of Previous Sections As Needed
This space provided for additional information or continuation of information from previous
sections as needed.
E-36 Page 1 of 4 Revised 02/22
Development Services
Land Development Engineering
1635 Faraday Avenue
442-339-2750
www.carlsbadca.gov
STANDARD PROJECT
REQUIREMENT
CHECKLIST
E-36
Project Information
Project Name:
Project ID:
DWG No. or Building Permit No.:
Baseline BMPs for Existing and Proposed Site Features
Complete the Table 1 - Site Design Requirement to document existing and proposed site features and the BMPs to be
implemented for them. All BMPs must be implemented where applicable and feasible. Applicability is generally
assumed if a feature exists or is proposed.
BMPs must be implemented for site design features where feasible. Leaving the box for a BMP unchecked means it
will not be implemented (either partially or fully) either because it is inapplicable or infeasible. Explanations must be
provided in the area below. The table provides specific instructions on when explanations are required.
Table 1 - Site Design Requirement
A. Existing Natural Site Features (see Fact Sheet BL-1)
1. Check the boxes below for each existing feature on
the site.
1. Select the BMPs to be implemented for each identified feature. Explain
why any BMP not selected is infeasible in the area below.
SD-G
Conserve natural
features
SD-H
Provide buffers around waterbodies
Natural waterbodies
Natural storage reservoirs & drainage corridors --
Natural areas, soils, & vegetation (incl. trees) --
B. BMPs for Common Impervious Outdoor Site Features (see Fact Sheet BL-2)
1. Check the boxes below for each
proposed feature.
2. Select the BMPs to be implemented for each proposed feature. If neither BMP SD-B nor
SD-I is selected for a feature, explain why both BMPs are infeasible in the area below.
SD-B
Direct runoff to pervious
areas
SD-I
Construct surfaces from
permeable materials
Minimize size of
impervious areas
Streets and roads Check this box to confirm
that all impervious areas on
the site will be minimized
where feasible.
If this box is not checked,
identify the surfaces that
cannot be minimized in area
below, and explain why it is
Sidewalks & walkways
Parking areas & lots
Driveways
Patios, decks, & courtyards
Hardcourt recreation areas
□
□
□
□
□
□
□
□
□
C cityof
Carlsbad
□
□
□
□
□
□
□ □
□
□
□ □
□
□
□
□
□
E-36 Page 2 of 4 Revised 02/22
Other: _______________ infeasible to do so.
C. BMPs for Rooftop Areas: Check this box if rooftop areas are proposed and select at least one BMP
below.
If no BMPs are selected, explain why they are infeasible in the area below.
(see Fact
Sheet BL-3)
SD-B
Direct runoff to pervious areas
SD-C
Install green roofs
SD-E
Install rain barrels
D. BMPs for Landscaped Areas: Check this box if landscaping is proposed and select the BMP below
SD-K Sustainable Landscaping
If SD-K is not selected, explain why it is infeasible in the area below.
(see Fact
Sheet BL-4)
Provide discussion/justification for site design BMPs that will not be implemented (either partially or fully):
Baseline BMPs for Pollutant-generating Sources
All development projects must complete Table 2 - Source Control Requirement to identify applicable requirements for
documenting pollutant-generating sources/ features and source control BMPs.
BMPs must be implemented for source control features where feasible. Leaving the box for a BMP unchecked means it
will not be implemented (either partially or fully) either because it is inapplicable or infeasible. Explanations must be
provided in the area below. The table provides specific instructions on when explanations are required.
Table 2 - Source Control Requirement
A. Management of Storm Water Discharges
1. Identify all proposed outdoor
work areas below
Check here if none are proposed
2. Which BMPs will be used to prevent
materials from contacting rainfall or
runoff?
(See Fact Sheet BL-5)
Select all feasible BMPs for each work area
3. Where will runoff from the
work area be routed?
(See Fact Sheet BL-6)
Select one or more option for each
work area
SC-A
Overhead
covering
SC-B
Separation
flows from
adjacent
areas
SC-C
Wind
protection
SC-D
Sanitary
sewer
SC-E
Containment
system
Other
Trash & Refuse Storage
Materials & Equipment Storage
□ □ □
D
□ □ □
D
D
□
□ □ □ □ □ □ □
□ □ □ □ □ □ □
E-36 Page 3 of 4 Revised 02/22
Loading & Unloading
Fueling
Maintenance & Repair
Vehicle & Equipment Cleaning
Other: _________________
B. Management of Storm Water Discharges (see Fact Sheet BL-7)
Select one option for each feature below:
• Storm drain inlets and catch basins … are not proposed
will be labeled with stenciling or signage to
discourage dumping (SC-F)
• Interior work surfaces, floor drains &
sumps …
are not proposed
will not discharge directly or indirectly to the MS4
or receiving waters
• Drain lines (e.g. air conditioning, boiler,
etc.) …
are not proposed
will not discharge directly or indirectly to the MS4
or receiving waters
• Fire sprinkler test water … are not proposed will not discharge directly or indirectly to the MS4
or receiving waters
Provide discussion/justification for source control BMPs that will not be implemented (either partially or fully):
□ □ □ □ □ □ □
□ □ □ □ □ □ □
□ □ □ □ □ □ □
□ □ □ □ □ □ □
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E-36 Page 4 of 4 Revised 02/22
Form Certification
This E-36 Form is intended to comply with applicable requirements of the city’s BMP Design Manual. I certify that it has
been completed to the best of my ability and accurately reflects the project being proposed and the applicable BMPs
proposed to minimize the potentially negative impacts of this project's land development activities on water quality. I
understand and acknowledge that the review of this form by City staff is confined to a review and does not relieve me as
the person in charge of overseeing the selection and design of storm water BMPs for this project, of my responsibilities for
project design.
Preparer Signature: Date:
Print preparer name:
I
SUMMARY OF PDP STRUCTURAL BMPS
PDP Structural BMPs
All PDPs must implement structural BMPs for storm water pollutant control (see Chapter 5 of
the BMP Design Manual). Selection of PDP structural BMPs for storm water pollutant control
must be based on the selection process described in Chapter 5. PDPs subject to
hydromodification management requirements must also implement structural BMPs for flow
control for hydromodification management (see Chapter 6 of the BMP Design Manual). Both
storm water pollutant control and flow control for hydromodification management can be
achieved within the same structural BMP(s).
PDP structural BMPs must be verified by the City at the completion of construction. This may
include requiring the project owner or project owner's representative to certify construction of
the structural BMPs (see Section 1.12 of the BMP Design Manual). PDP structural BMPs must
be maintained into perpetuity, and the City must confirm the maintenance (see Section 7 of the
BMP Design Manual).
Use this form to provide narrative description of the general strategy for structural BMP
implementation at the project site in the box below. Then complete the PDP structural BMP
summary information sheet for each structural BMP within the project (copy the BMP summary
information page as many times as needed to provide summary information for each individual
structural BMP).
Describe the general strategy for structural BMP implementation at the site. This information
must describe how the steps for selecting and designing storm water pollutant control BMPs
presented in Section 5.1 of the BMP Design Manual were followed, and the results (type of
BMPs selected). For projects requiring hydromodification flow control BMPs, indicate whether
pollutant control and flow control BMPs are integrated together or separate.
Based on the site being a graded compacted pad and it has been raised with fill about 10 to 20
feet to the native soil and the fact that some of the BMPs will be required to be placed next to the
building footprint, infiltration BMPs are considered infeasible on a geotechnical building foundation
basis. Geotechnical report is provided for this project and Worksheet C.4-1 was completed by the
soil engineer to address infiltration feasibility. All the BMPs are utilized as pollutant control and
flow control BMPs. The first step for each BMP (biofiltration) area was to divide up the site into
appropriate DMA areas.
All DMAs drain to a BMP and no self-mitigating or self-retaining except a small portion (DMA 7)
that is considered as De Minimis area. Runoff factor was adjusted to calculate the DCV and
provided in the attachment 1b.
Referring to Section 5.4.1 Harvest and Use area not feasible for this project since the 0.25 of the
DCV is less than 36 hour demand. The next step is to check the infiltration feasibility by using
Section 5.4.2; based on soil engineer investigation the infiltration rate is less than 0.25 inches in
several hours. Therefore infiltration condition is not recommended and the Biofiltration with
impervious liner is selected as the BMP type. Sizing requirements are computed based on
Appendix B.5 and since the BMP can be designed for the remaining DCV and BMP was designed
for the required size, per design criteria and considerations listed in the fact sheets Appendix E.
[Continued from previous page – This page is reserved for continuation of description of general
strategy for structural BMP implementation at the site.]
North Coast Medical Phase I site has an overall decrease in the impervious area of the site. To
accommodate the required amount of parking needed for both the Phase I and Phase II project
site, additional parking was to be constructed on the Phase I site. As such, additional islands
and grading to the driveway was to be done. The overall hydrological change is a net zero for
the Phase I site, in addition there was an additional bio retention basin added to the North West
corner of the entry driveway. As such, the area that was primarily an existing impervious
surface is now more pervious and being diverted to an additional basin. The void that was
created was to account for the resurfacing across the rest of the Phase I site. The following was
tabulated and added to an exhibit in attachment 1A along with the DMA exhibit in the report.
The entry driveway on Phase I is regraded to change the flow pattern of the runoff, to allow the
runoff to flow west from a highpoint to an sidewalk underdrain then down to a bio filtration basin
(The existing runoff flows east and is taking to an existing catch basin). Removing this section
of area from the existing hydrology has created a gap in the existing runoff conditions. This
“bonus” was attributed to allow the compensation to be made up for the “De minimus” areas,
and the small areas to be regraded on the Phase I project site.
The Phase II project area layout proposes to install a single medical office building (with an
above-ground parking garage beneath the three story building) in the central portion of the
property with the main drive aisle connecting the west and east parcels located along the south
side of the building (already installed). Parking stalls and associated drive aisles will be located
west of the building (already installed and paved – but with some restriping) where the main
entrance will be, the north side of the building, the east side of the building, and two drive aisles
will be installed running south-to-north through the building’s garage. The roof of the building
will sheet flow west to east with four (4) roof drain locations on the east side of the building.
Runoff from the roof will discharge to the splash pads and then ultimately combine with the
parking area flows to collect in the biofiltration basins. Parking areas have been graded to drain
to the biofiltration basins as well where a total of six (6) water quality biofiltration basins are to
be installed around the site to treat the new roof and parking surfaces (accounting for landscape
area runoff as well).
Structural BMP Summary Information
[Copy this page as needed to provide information for each individual proposed
structural BMP]
Structural BMP ID No. A
DWG 496-1B SHEETS 7, 8
Type of structural BMP:
Retention by harvest and use (HU-1)
Retention by infiltration basin (INF-1)
Retention by bioretention (INF-2)
Retention by permeable pavement (INF-3)
Dry Wells (INF-4)
Partial retention by biofiltration with partial retention (PR-1)
Biofiltration (BF-1)
Proprietary Biofiltration (BF-3)
Flow-thru treatment control included as pre-treatment/forebay for an onsite retention or
biofiltration BMP (provide BMP type/description and indicate which onsite retention or
biofiltration BMP it serves in discussion section below)
Detention pond or vault for hydromodification management
Trash Capture Device
Other (describe in discussion section below)
Purpose:
Pollutant control only
Hydromodification control only
Combined pollutant control and hydromodification control
Pre-treatment/forebay for another structural BMP
Trash Capture
Other (describe in discussion section below)
Discussion (as needed):
All of the BMPs used on this project are biofiltration units that are designed per worksheet B.5-1
of the COC BMP Design Manual and modeled using continuous simulation modeling with
SWMM. BMP-A is a biofiltration basin that has 318 sqft of effective area. The dimensions of this
basin section are as follows: 15” from top of basin to basin finish surface (includes 3” of mulch),
18” of soil media, and 27” of gravel for a total depth of 60” from top of BMP to bottom of BMP.
This basin will include a 20-30 mil impermeable liner, 36”x36” catch basin overflow structure with
BioClean grated inlet filter, and a 6” diameter minimum perforated under drain pipe 3” above
bottom of basin with a 0.5” diameter lower orifice at the perforated pipe flowline. The provided
biofiltration volume of this basin is 207 cubic feet and the final design capture volume is 199
cubic feet.
V
V
Structural BMP Summary Information
[Copy this page as needed to provide information for each individual proposed
structural BMP]
Structural BMP ID No. B
DWG 496-1B SHEETS 7, 8
Type of structural BMP:
Retention by harvest and use (HU-1)
Retention by infiltration basin (INF-1)
Retention by bioretention (INF-2)
Retention by permeable pavement (INF-3)
Dry Wells (INF-4)
Partial retention by biofiltration with partial retention (PR-1)
Biofiltration (BF-1)
Proprietary Biofiltration (BF-3)
Flow-thru treatment control included as pre-treatment/forebay for an onsite retention or
biofiltration BMP (provide BMP type/description and indicate which onsite retention or
biofiltration BMP it serves in discussion section below)
Detention pond or vault for hydromodification management
Trash Capture Device
Other (describe in discussion section below)
Purpose:
Pollutant control only
Hydromodification control only
Combined pollutant control and hydromodification control
Pre-treatment/forebay for another structural BMP
Trash Capture
Other (describe in discussion section below)
Discussion (as needed):
All of the BMPs used on this project are biofiltration units that are designed per worksheet B.5-1
of the COC BMP Design Manual and modeled using continuous simulation modeling with
SWMM. BMP-B is a biofiltration basin that has 498 sqft of effective area. The dimensions of this
basin section are as follows: 19” from top of basin to basin finish surface (includes 3” of mulch),
18” of soil media, and 27” of gravel for a total depth of 64” from top of BMP to bottom of BMP.
This basin will include a 20-30 mil impermeable liner, 24”x24” catch basin overflow structure with
BioClean grated inlet filter, and a 6” diameter minimum perforated under drain pipe 3” above
bottom of basin with a 0.5” diameter lower orifice at the perforated pipe flowline. The provided
biofiltration volume of this basin is 221 cubic feet and the final design capture volume is 239
cubic feet.
V
V
Structural BMP Summary Information
[Copy this page as needed to provide information for each individual proposed
structural BMP]
Structural BMP ID No. C
DWG 496-1B SHEETS 7, 8
Type of structural BMP:
Retention by harvest and use (HU-1)
Retention by infiltration basin (INF-1)
Retention by bioretention (INF-2)
Retention by permeable pavement (INF-3)
Dry Wells (INF-4)
Partial retention by biofiltration with partial retention (PR-1)
Biofiltration (BF-1)
Proprietary Biofiltration (BF-3)
Flow-thru treatment control included as pre-treatment/forebay for an onsite retention or
biofiltration BMP (provide BMP type/description and indicate which onsite retention or
biofiltration BMP it serves in discussion section below)
Detention pond or vault for hydromodification management
Trash Capture Device
Other (describe in discussion section below)
Purpose:
Pollutant control only
Hydromodification control only
Combined pollutant control and hydromodification control
Pre-treatment/forebay for another structural BMP
Trash Capture
Other (describe in discussion section below)
Discussion (as needed):
All of the BMPs used on this project are biofiltration units that are designed per worksheet B.5-1
of the COC BMP Design Manual and modeled using continuous simulation modeling with
SWMM. BMP-C is a biofiltration basin that has 1,336 sqft of effective area. The dimensions of
this basin section are as follows: 15” from top of basin to basin finish surface (includes 3” of
mulch), 18” of soil media, and 21” of gravel for a total depth of 54” from top of BMP to bottom of
BMP. This basin will include a 20-30 mil impermeable liner, 24”x24” catch basin overflow
structure with BioClean grated inlet filter, and a 6” diameter minimum perforated under drain pipe
3” above bottom of basin with a 0.75” diameter lower orifice at the perforated pipe flowline. The
provided biofiltration volume of this basin is 1,142 cubic feet and the final design capture volume
is 1,409 cubic feet.
V
V
Structural BMP Summary Information
[Copy this page as needed to provide information for each individual proposed
structural BMP]
Structural BMP ID No. D
DWG 496-1B SHEETS 7, 8
Type of structural BMP:
Retention by harvest and use (HU-1)
Retention by infiltration basin (INF-1)
Retention by bioretention (INF-2)
Retention by permeable pavement (INF-3)
Dry Wells (INF-4)
Partial retention by biofiltration with partial retention (PR-1)
Biofiltration (BF-1)
Proprietary Biofiltration (BF-3)
Flow-thru treatment control included as pre-treatment/forebay for an onsite retention or
biofiltration BMP (provide BMP type/description and indicate which onsite retention or
biofiltration BMP it serves in discussion section below)
Detention pond or vault for hydromodification management
Trash Capture Device
Other (describe in discussion section below)
Purpose:
Pollutant control only
Hydromodification control only
Combined pollutant control and hydromodification control
Pre-treatment/forebay for another structural BMP
Trash Capture
Other (describe in discussion section below)
Discussion (as needed):
All of the BMPs used on this project are biofiltration units that are designed per worksheet B.5-1
of the COC BMP Design Manual and modeled using continuous simulation modeling with
SWMM. BMP-D is a biofiltration basin that has 1,540 sqft of effective area. The dimensions of
this basin section are as follows: 15” from top of basin to basin finish surface (includes 3” of
mulch), 18” of soil media, and 15” of gravel for a total depth of 48” from top of BMP to bottom of
BMP. This basin will include a 20-30 mil impermeable liner, 24”x36” catch basin overflow
structure with BioClean grated inlet filter, and a 6” diameter minimum perforated under drain pipe
3” above bottom of basin with a 1” diameter lower orifice at the perforated pipe flowline. The
provided biofiltration volume of this basin is 1,033 cubic feet and the final design capture volume
is 981 cubic feet.
V
V
Structural BMP Summary Information
[Copy this page as needed to provide information for each individual proposed
structural BMP]
Structural BMP ID No. E
DWG 496-1B SHEETS 7, 8
Type of structural BMP:
Retention by harvest and use (HU-1)
Retention by infiltration basin (INF-1)
Retention by bioretention (INF-2)
Retention by permeable pavement (INF-3)
Dry Wells (INF-4)
Partial retention by biofiltration with partial retention (PR-1)
Biofiltration (BF-1)
Proprietary Biofiltration (BF-3)
Flow-thru treatment control included as pre-treatment/forebay for an onsite retention or
biofiltration BMP (provide BMP type/description and indicate which onsite retention or
biofiltration BMP it serves in discussion section below)
Detention pond or vault for hydromodification management
Trash Capture Device
Other (describe in discussion section below)
Purpose:
Pollutant control only
Hydromodification control only
Combined pollutant control and hydromodification control
Pre-treatment/forebay for another structural BMP
Trash Capture
Other (describe in discussion section below)
Discussion (as needed):
All of the BMPs used on this project are biofiltration units that are designed per worksheet B.5-1
of the COC BMP Design Manual and modeled using continuous simulation modeling with
SWMM. BMP-E is a biofiltration basin that has 508 sqft of effective area. The dimensions of this
basin section are as follows: 19” from top of basin to basin finish surface (includes 3” of mulch),
18” of soil media, and 15” of gravel for a total depth of 52” from top of BMP to bottom of BMP.
This basin will include a 20-30 mil impermeable liner, 24”x24” catch basin overflow structure with
BioClean grated inlet filter, and a 6” diameter minimum perforated under drain pipe 3” above
bottom of basin with a 0.5” diameter lower orifice at the perforated pipe flowline. The provided
biofiltration volume of this basin is 313 cubic feet and the final design capture volume is 305
cubic feet.
V
V
Structural BMP Summary Information
[Copy this page as needed to provide information for each individual proposed
structural BMP]
Structural BMP ID No. F
DWG 496-1B SHEETS 4, 8
Type of structural BMP:
Retention by harvest and use (HU-1)
Retention by infiltration basin (INF-1)
Retention by bioretention (INF-2)
Retention by permeable pavement (INF-3)
Dry Wells (INF-4)
Partial retention by biofiltration with partial retention (PR-1)
Biofiltration (BF-1)
Proprietary Biofiltration (BF-3)
Flow-thru treatment control included as pre-treatment/forebay for an onsite retention or
biofiltration BMP (provide BMP type/description and indicate which onsite retention or
biofiltration BMP it serves in discussion section below)
Detention pond or vault for hydromodification management
Trash Capture Device
Other (describe in discussion section below)
Purpose:
Pollutant control only
Hydromodification control only
Combined pollutant control and hydromodification control
Pre-treatment/forebay for another structural BMP
Trash Capture
Other (describe in discussion section below)
Discussion (as needed):
All of the BMPs used on this project are biofiltration units that are designed per worksheet B.5-1
of the COC BMP Design Manual and modeled using continuous simulation modeling with
SWMM. BMP-F is a biofiltration basin that has 389 sqft of effective area. The dimensions of this
basin section are as follows: 19” from top of basin to basin finish surface (includes 3” of mulch),
18” of soil media, and 15” of gravel for a total depth of 52” from top of BMP to bottom of BMP.
This basin will include a 20-30 mil impermeable liner, 24”x24” catch basin overflow structure with
BioClean grated inlet filter, and a 6” diameter minimum perforated under drain pipe 3” above
bottom of basin with a 0.5” diameter lower orifice at the perforated pipe flowline. The provided
biofiltration volume of this basin is 406 cubic feet and the final design capture volume is 351
cubic feet.
V
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ATTACHMENT 1
BACKUP FOR PDP POLLUTANT CONTROL BMPS
This is the cover sheet for Attachment 1.
Check which Items are Included behind this cover sheet:
Attachment
Sequence
Contents Checklist
Attachment 1a DMA Exhibit (Required)
See DMA Exhibit Checklist on the
back of this Attachment cover sheet.
(24”x36” Exhibit typically required)
Included
Attachment 1b Tabular Summary of DMAs Showing
DMA ID matching DMA Exhibit, DMA
Area, and DMA Type (Required)*
*Provide table in this Attachment OR
on DMA Exhibit in Attachment 1a
Included on DMA Exhibit in
Attachment 1a
Included as Attachment 1b,
separate from DMA Exhibit
Attachment 1c Form I-7, Harvest and Use Feasibility
Screening Checklist (Required unless
the entire project will use infiltration
BMPs)
Refer to Appendix B of the BMP
Design Manual to complete Form I-7.
Included
Not included because the entire
project will use infiltration BMPs
Attachment 1d Infiltration Feasibility Analysis
(Required unless the project will use
harvest and use BMPs)
Refer to Appendix D of the BMP
Design Manual.
Included
Not included because the entire
project will use harvest and use
BMPs
Attachment 1e Pollutant Control BMP Design
Worksheets / Calculations (Required)
Refer to Appendices B, E, and I of
the BMP Design Manual for structural
pollutant control BMP design
guidelines
Included
Attachment 1f Trash Capture BMP Design
Calculations
Refer to Appendices J of the BMP
Design Manual for Trash capture BMP
design guidelines
Included
Not included because the entire
project is not subject to trash
capture requirements
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V
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V
Use this checklist to ensure the required information has been included on the DMA
Exhibit:
The DMA Exhibit must identify:
Underlying hydrologic soil group
Approximate depth to groundwater
Existing natural hydrologic features (watercourses, seeps, springs, wetlands)
Critical coarse sediment yield areas to be protected (if present)
Existing topography and impervious areas
Existing and proposed site drainage network and connections to drainage offsite
Proposed grading
Proposed impervious features
Proposed design features and surface treatments used to minimize imperviousness
Drainage management area (DMA) boundaries, DMA ID numbers, and DMA areas (square
footage or acreage), and DMA type (i.e., drains to BMP, self-retaining, or self-mitigating)
Structural BMPs (identify location and type of BMP)
Tabular DMA Summary
ATTACHMENT 1a
DMA EXHIBIT FOR
NORTH COAST MEDICAL PLAZA PHASE I & II
FH
FH
FH
V
FH
V
V
V
V
◊
◊
DMA 3
DMA 4
DMA 1
DMA 2
DMA 5
DMA 7
HI
D
D
E
N
V
A
L
L
E
Y
R
O
A
D
DMA 6
BMP C
BMP D
BMP E
BMP B
BMP F
PALOMAR AIRPORT ROAD
**AIA/NlENANCE AREA NO!E
SEE I.IA/NTENANCE EXHIBIT SHOW/NC
TH£ 01€RALL SITE II.IPERVIOIJS
PERCENTAGE REDt/CllON.
,.--CATCH BASIN
PER PLAN
SCH 40 PVC NALE
AOAPTER (l.lilPKSoC)
SCH 40 PVC 1HR£A0£0
EN/J CAP (FPT)
-===,,c~c,c===Jr--'l,--IJRII.L OR/flCE HOI.£ AT
lliN. 3LJ, £'.](_ R.OJll./NE OF EN/J CAP ~ ~. , 'SHli.i?= ; (SIZE PER BIO-BASIN
\_,,,., Stll.ll.lAR Y TAB!.£)
Na 57STON£
OR/RC£ OETAIL
NOT TO SCALE
6" PVC PIPE PERFORAllON
LA YOIJT OETAIL
NOT TO SCALE
NO LIi€ L/W
LOA/JIM LOA/JING
/I.IPERVIOIJS PERVIOIJS
/JI.IA 1/J /JI.IA AREA AREA AREA /JI.IA /JRAINS TO T>PE OF Bl.IP
(SQFT} (SQFT} (SQFT)
/JI.IA-! 5,093 4,168 925 /JRAINS TO Bl.IP-A 8/0RL lRA 110N
/JI.IA-2 6,645 4,844 1,801 /JRAINS TO BI.IP-8 8/0RL lRA 110N
/JI.IA-3 34,369 30,507 ~862 /JRAINS TO BI.IP-C 8/0RL lRA 110N
/JI.IA-4 24,824 20,764 4,060 /JRAINS TO BI.IP-/J 8/0RL lRA 110N
/JI.IA-5 8,702 6,633 2,069 /JRA/NS TO Bl.IP-£ 8/0RL lRA 110N
/JI.IA-6 9,481 7,149 2,JJ! /JRA/NS TO BI.IP-F 8/0RL lRA 110N
/JI.IA-7 333 333 0 /JE I.I/N/1.1/S N/A
TOTAL 89,446 74,398 15,048
REQIJIRE/J
/JCV
(CF}
199
239
1,409
98!
322
35!
N/A
I
I
I I
I
~
IZ I
I
I
I
I -
PROVI/JE/J
8/0RL lRA 110N
VOl..ll!.1£'
(CF)
283
313
1,789
1,334
434
487
N/A
/JI.IA Stll.ll.lAR Y TABLE
EFF£C111€ NA)(
HYOROI.IOI)
Bl.IP AREA {IN/JER/JRAIN
(SQFT) R.OWl?A TE (CFS)
14! aot35
498 aot35
1,336 ao285
1,4!! ao303
508 ao!!8
389 ao!!8
N/A N/A
4,285
TOP OF 1.1£/J/A RISER CI.EANOtJT Bl.IP C A! A2 A3
(INCH} (INCH) (INCH} {INCH)
9.75 15 9 18
9 19 9 18
9 15 9 18
9 15 9 18
10 19 9 18
17 19 9 18
N/A N/A N/A N/A
LEGEND
1-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-1 .............................. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
------------
->-->-->-
----}(}(----
----%%----
- --(XX}-- -
CRAl-fZ
/}
(INCH}
24
24
18
24
12
12
N/A
tl m
□
•
BOX RISER/
£ OIIEli'flOlf
S1R(JC 1//RE (ffET) SIZE (INCHES)
3.25 36)(36
4.25 24)(24
3.25 24)(24
3.25 24)(36
4.25 24)(24
4.25 24)(24
N/A N/A
PROPERTY BOIJNOARY
£AS£1.1£NT LIN£
PROPOSE/J II.IPERV!Ol/S AREA
(AC OR/I€ AISLE)
PROPOSE/J /l,(P£RV!Ol/S AREA
(AC PARK/NC}
PROPOSE/J /l,(P£RV!Ol/S AREA
(CONCRETE)
PROPOSE/J /l,(P£RV!Ol/S AREA
(Bll/ilJINC)
PROPOSE/J PERVIOl/S AREA
/JAIA BOIJNOARY
R.Olf /JIRECTlON (st/RFACE)
R.Olf /JIRECTION (STORV ORAIN)
PROPOSE/J l,(A.JIJR CONTOl/R
PROPOSE/J VINOR CONTOl/R
£)(!S11NC VA.J/JR CONTOUR
£)(!S11NC l,f/NOR CONli?t/R
£)(!S11NC STORA/ ORAIN
PROPOSE/J STORV /JRAIN
PROPOSE/J CATCH BASIN
PROPOSE/J RIP RAP
PROPOSE/J Cl/RB {INOERORAIN
PROPOSE/J Cl/RB OPENING
POINT OF CO/,IPLIANCE
LOl/£R OR/flCE /I.IPERI.IEABLE
IJ!Al,(£1ER (INCH) LINER?
a5 YES
Q5625 YES
a75 YES
a75 YES
a5 YES
a5 YES
N/A N/A
'PROVI/JE/J 8/0RLlRATlON VOl..ll!.1£ PER 8.3 Bl.IP PERFORI.IANCE HVRKSHEET ROif 27 (VOl..ll!.1£ RETAINE/J BY Bl.IP} + ROif 42 (PROVI/JE/J 8/0fiLlRATlON VOl..tl!.1£}
HYDROLOGICAL SOIL CROIJP
TH£ H!1?0LOCICAL SCVL CROUP FOR
THIS SITE IS T>PE (C) SCALE !"=40'
NO!E·
APPRO)(fl.lA TE 0£P1H TO CROtJN/JlfA !ER
IS 14' (PER CEOTECHN/CAI. REPORT
/JATElJ 9 S£P!D,(8£R 2022)
------ -0 40 80 120 160
EXCEL
ENGINEERING
W/0 IWIMIIG •E.NQNff/1//(/, • SIJRl£11NG
#II SW[ PUCE, ESW/IJI/JO, CA 92029
ffl {760)lf5-8118 fX {760)745-ll!JO
FH
FH
FH
V
FH
V
V
V
V
◊
◊
HI
D
D
E
N
V
A
L
L
E
Y
R
O
A
D
DMA 3
DMA 4
DMA 1
DMA 2
DMA 5
DMA 6
DMA 7
FH
FH
FH
V
FH
V
V
V
V
◊
◊
HI
D
D
E
N
V
A
L
L
E
Y
R
O
A
D
DISTURBED MAINTENANCE AREA EXHIBIT FOR
NORTH COAST MEDICAL PLAZA PHASE I & II
I
I
I \
\
/ r
POST OEvELOPEO SITE
#MA/NlFNANCE~~
AREA--1 I
-110 TOTAL SF
/
I 0~
/
(
E}(ISTlNC 8(//LO/NC
(NOTA PART)
~MAIN!FNANCE
AREA-J
1,293 TOTAL SF
E%/S71NC SITE
/
IMPERv?OUS v.5: PERv?OUS S/JMMARY TABLE **MAINTENANCE AREA NOTE
MAIN!ENANCE E)(f!IBIT TO SHOW 1HE OYERALL
SITE IMPERVIOIJS PERCENT,4CE REOLICTlON. EXISTlNC PROPOSED OEl.T,4
(SOFT) (SOFT) (SOFT)
INPERVIOIJS 8,572 8,551 -21
PERVIOIJS 2,2-IJ 2,26-1 +21
TOTAL 10,815 10,815
POST OEvELOPEO SITE IMPERVIOUS v.5: PERVIOUS TABLE
MAIN!ENANCE
AREA /0
AREA 1
AREA 2
AREA J
AREA -I
AREA 5
AREA 6
INPERVIOIJS PERVIOIJS TOTAL AREA
(SOFT) (SOFT) (SOFT)
714
1,999
1,029
410
221
4,178
499 1,213
52 2,051
26-1 1,293
0 410
278 499
1,171 5,J-19
14815 77Jli4L SITE AIA/NlENANCE AH£A
LEGEND
------------
---xx---
---YY---
PROPERTY Bot/NOARY
EAS£l,IENT LINE
OIIA Bot/NOARY
PROPOSEIJ MAJOR CONTOIJR
PROPOSE!J MINOR CONTOIJR
- --(X%)-- -EXISTlNC MAJOR CONTot/R
-(X%} E}(ISTlNC MINOR CONTOIJR
IMPERV/ot/S AREA
E%/S71NC SITE IMPERVIOUS v.5: PERVIO/JS TABLE
MAIN!ENANCE
AREA /0
AREA 1
AREA 2
AREA J
AREA -I
AREA 5
AREA 6
INPERVIOIJS PERVIOIJS TOTAL AREA
(SOFT) (SOFT) (SOFT)
1,150 6J 1,213
2,006 -15 2,051
711 582 1,293
255 155 410
499 0 499
3,951 1,398 5,J-19
14815 77Jli4L SITE AIA/NlENANCE AH£A
SCALE f'=#J' ---- -- -0 -10 80 120 160
EXCEL
ENGINEERING
LANI) IWIMIIG •EIIGIN£f/l///G • Sllllfl7IIG
#II SfAI[ PlAa; E.SIXDJO. CA 92029
ff/ {760)745-8118 FX (760)745-1890
ATTACHMENT 1b
Category # Description i ii iii iv v vi Units
1 Drainage Basin ID or Name DMA-1 DMA-2 DMA-3 DMA-4 DMA-5 DMA-6 unitless
2 85th Percentile 24-hr Storm Depth 0.60 0.60 0.60 0.60 0.60 0.60 inches
3 Impervious Surfaces Not Directed to Dispersion Area (C=0.90) 4,168 4,844 30,507 20,764 6,633 7,149 sq-ft
4 Semi-Pervious Surfaces Not Serving as Dispersion Area (C=0.30) sq-ft
5 Engineered Pervious Surfaces Not Serving as Dispersion Area (C=0.10) sq-ft
6 Natural Type A Soil Not Serving as Dispersion Area (C=0.10) sq-ft
7 Natural Type B Soil Not Serving as Dispersion Area (C=0.14) sq-ft
8 Natural Type C Soil Not Serving as Dispersion Area (C=0.23) 925 1,801 3,862 4,060 2,069 2,331 sq-ft
9 Natural Type D Soil Not Serving as Dispersion Area (C=0.30) sq-ft
10 Does Tributary Incorporate Dispersion, Tree Wells, and/or Rain Barrels? yes/no
11 Impervious Surfaces Directed to Dispersion Area per SD-B (Ci=0.90) sq-ft
12 Semi-Pervious Surfaces Serving as Dispersion Area per SD-B (Ci=0.30) sq-ft
13 Engineered Pervious Surfaces Serving as Dispersion Area per SD-B (Ci=0.10) sq-ft
14 Natural Type A Soil Serving as Dispersion Area per SD-B (Ci=0.10) sq-ft
15 Natural Type B Soil Serving as Dispersion Area per SD-B (Ci=0.14) sq-ft
16 Natural Type C Soil Serving as Dispersion Area per SD-B (Ci=0.23) sq-ft
17 Natural Type D Soil Serving as Dispersion Area per SD-B (Ci=0.30) sq-ft
18 Number of Tree Wells Proposed per SD-A #
19 Average Mature Tree Canopy Diameter ft
20 Number of Rain Barrels Proposed per SD-E #
21 Average Rain Barrel Size gal
22 Total Tributary Area 5,093 6,645 34,369 24,824 8,702 9,480 sq-ft
23 Initial Runoff Factor for Standard Drainage Areas 0.78 0.72 0.82 0.79 0.74 0.74 unitless
24 Initial Runoff Factor for Dispersed & Dispersion Areas 0.00 0.00 0.00 0.00 0.00 0.00 unitless
25 Initial Weighted Runoff Factor 0.78 0.72 0.82 0.79 0.74 0.74 unitless
26 Initial Design Capture Volume 199 239 1,409 981 322 351 cubic-feet
27 Total Impervious Area Dispersed to Pervious Surface 0 0 0 0 0 0 sq-ft
28 Total Pervious Dispersion Area 0 0 0 0 0 0 sq-ft
29 Ratio of Dispersed Impervious Area to Pervious Dispersion Area n/a n/a n/a n/a n/a n/a ratio
30 Adjustment Factor for Dispersed & Dispersion Areas 1.00 1.00 1.00 1.00 1.00 1.00 ratio
31 Runoff Factor After Dispersion Techniques 0.78 0.72 0.82 0.79 0.74 0.74 unitless
32 Design Capture Volume After Dispersion Techniques 199 239 1,409 981 322 351 cubic-feet
33 Total Tree Well Volume Reduction 0 0 0 0 0 0 cubic-feet
34 Total Rain Barrel Volume Reduction 0 0 0 0 0 0 cubic-feet
35 Final Adjusted Runoff Factor 0.78 0.72 0.82 0.79 0.74 0.74 unitless
36 Final Effective Tributary Area 3,973 4,784 28,183 19,611 6,439 7,015 sq-ft
37 Initial Design Capture Volume Retained by Site Design Elements 0 0 0 0 0 0 cubic-feet
38 Final Design Capture Volume Tributary to BMP 199 239 1,409 981 322 351 cubic-feet
Tree & Barrel
Adjustments
Results
No Warning Messages
False
False
Dispersion
Area
Adjustments
Automated Worksheet B.1: Calculation of Design Capture Volume (V1.0)
Standard
Drainage Basin
Inputs
Dispersion
Area, Tree Well
& Rain Barrel
Inputs
(Optional)
Initial Runoff
Factor
Calculation
Category # Description i ii iii iv v vi Units
1 Drainage Basin ID or Name DMA-1 DMA-2 DMA-3 DMA-4 DMA-5 DMA-6 unitless
2 85th Percentile Rainfall Depth 0.60 0.60 0.60 0.60 0.60 0.60 inches
3 Predominant NRCS Soil Type Within BMP Location C C C C C C unitless
4 Is proposed BMP location Restricted or Unrestricted for Infiltration Activities? Unrestricted Unrestricted Unrestricted Unrestricted Unrestricted Unrestricted unitless
5 Nature of Restriction unitless
6 Do Minimum Retention Requirements Apply to this Project? yes/no
7 Are Habitable Structures Greater than 9 Stories Proposed? yes/no
8 Has Geotechnical Engineer Performed an Infiltration Analysis? yes/no
9 Design Infiltration Rate Recommended by Geotechnical Engineer in/hr
10 Design Infiltration Rate Used To Determine Retention Requirements 0.100 0.100 0.100 0.100 0.100 0.100 in/hr
11 Percent of Average Annual Runoff that Must be Retained within DMA 22.2% 22.2% 22.2% 22.2% 22.2% 22.2% percentage
12 Fraction of DCV Requiring Retention 0.15 0.15 0.15 0.15 0.15 0.15 ratio
13 Required Retention Volume 30 36 211 147 48 53 cubic-feet
False
False
Automated Worksheet B.2: Retention Requirements (V1.0)
Basic Analysis
Advanced
Analysis
Result
No Warning Messages
ATTACHMENT 1c
Harvest and Use Feasibility Checklist
Form I-7
1. Is there a demand for harvested water (check all that apply) at the project site that is reliably present during
the wet season?
Toilet and urinal flushing
Landscape irrigation
Other:
2. If there is a demand; estimate the anticipated average wet season demand over a period of 36 hours. Guidance
for planning level demand calculations for toilet/urinal flushing and landscape irrigation is provided in Section
B.3.2.
Flushing: (499 employees)x(7gallon usage) = 3493 gallons (3493 gallons)(1.5day) / (7.48gal/cu feet) =
700 cubic feet
Irrigation: Per Appendix B.3.2.2, there is no need to include in calculation due to use of reclaimed water.
3. Calculate the DCV using worksheet B.2-1.
DCV = 3364 (cubic feet)
3a. Is the 36 hour demand greater
than or equal to the DCV?
Yes / No
3b. Is the 36 hour demand greater than
0.25DCV but less than the full DCV?
Yes / No
3c. Is the 36 hour demand
less than 0.25DCV?
Yes
Harvest and use appears to be
feasible. Conduct more detailed
evaluation and sizing calculations
to confirm that DCV can be used
at an adequate rate to meet
drawdown criteria.
Harvest and use may be feasible.
Conduct more detailed evaluation and
sizing calculations to determine
feasibility. Harvest and use may only be
able to be used for a portion of the site,
or (optionally) the storage may need to be
upsized to meet long term capture targets
while draining in longer than 36 hours.
Harvest and use is
considered to be infeasible.
Is harvest and use feasible based on further evaluation?
Yes, refer to Appendix E to select and size harvest and use BMPs.
No, select alternate BMPs.
~
~ ¢:::J 0 ¢:::J 0
¢:::J
-
ATTACHMENT 1d
Categorization of Infiltration Feasibility Condition Form I-8
Part 1 - Full Infiltration Feasibility Screening Criteria
Would infiltration of the full design volume be feasible from a physical perspective without any
undesirable consequences that cannot be reasonably mitigated?
Criteria Screening Question Yes No
1
Is the estimated reliable infiltration rate below proposed facility locations greater than
0.5 inches per hour? The response to this Screening Question shall be based on a
comprehensive evaluation of the factors presented in Appendix C.2 and Appendix D.
Provide basis:
2
Can infiltration greater than 0.5 inches per hour be allowed without increasing risk of
geotechnical hazards (slope stability, groundwater mounding, utilities, or other factors)
that cannot be mitigated to an acceptable level? The response to this Screening Question
shall be based on a comprehensive evaluation of the factors presented in Appendix
C.2.
Provide basis:
I
Form I-8 Page 2 of 4
Criteria Screening Question Yes No
3
Can infiltration greater than 0.5 inches per hour be allowed without increasing risk of
groundwater contamination (shallow water table, storm water pollutants or other
factors) that cannot be mitigated to an acceptable level? The response to this Screening
Question shall be based on a comprehensive evaluation of the factors presented in
Appendix C.3.
Provide basis:
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability.
4
Can infiltration greater than 0.5 inches per hour be allowed without causing potential
water balance issues such as change of seasonality of ephemeral streams or increased
discharge of contaminated groundwater to surface waters? The response to this
Screening Question shall be based on a comprehensive evaluation of the factors
presented in Appendix C.3.
Provide basis:
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability.
Part 1
Result*
If all answers to rows 1 - 4 are “Yes” a full infiltration design is potentially feasible. The
feasibility screening category is Full Infiltration
If any answer from row 1-4 is “No”, infiltration may be possible to some extent but would not
generally be feasible or desirable to achieve a “full infiltration” design. Proceed to Part 2
*To be completed using gathered site information and best professional judgment considering the definition of MEP in
the MS4 Permit. Additional testing and/or studies may be required by City Engineer to substantiate findings.
Form I-8 Page 3 of 4
Part 2 – Partial Infiltration vs. No Infiltration Feasibility Screening Criteria
Would infiltration of water in any appreciable amount be physically feasible without any negative
consequences that cannot be reasonably mitigated?
Criteria Screening Question Yes No
5
Do soil and geologic conditions allow for infiltration in any appreciable rate or volume?
The response to this Screening Question shall be based on a comprehensive evaluation
of the factors presented in Appendix C.2 and Appendix D.
Provide basis:
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability and why it was not feasible to mitigate low infiltration rates.
6
Can Infiltration in any appreciable quantity be allowed without increasing risk of
geotechnical hazards (slope stability, groundwater mounding, utilities, or other factors)
that cannot be mitigated to an acceptable level? The response to this Screening Question
shall be based on a comprehensive evaluation of the factors presented in Appendix
C.2.
Provide basis:
Form I-8 Page 4 of 4
Criteria Screening Question Yes No
7
Can Infiltration in any appreciable quantity be allowed without posing significant risk
for groundwater related concerns (shallow water table, storm water pollutants or other
factors)? The response to this Screening Question shall be based on a comprehensive
evaluation of the factors presented in Appendix C.3.
Provide basis:Groundwater is not located within approximately 10 feet from the bottom of the proposed basins.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability and why it was not feasible to mitigate low infiltration rates.
8
Can infiltration be allowed without violating downstream water rights? The response to
this Screening Question shall be based on a comprehensive evaluation of the factors
presented in Appendix C.3.
Provide basis:
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability and why it was not feasible to mitigate low infiltration rates.
Part 2
Result*
If all answers from row 1-4 are yes then partial infiltration design is potentially feasible.
The feasibility screening category is Partial Infiltration
If any answer from row 5-8 is no, then infiltration of any volume is considered to be
infeasible within the drainage area. The feasibility screening category is No Infiltration.
*To be completed using gathered site information and best professional judgment considering the definition of MEP in
the MS4 Permit. Additional testing and/or studies may be required by City Engineer to substantiate findings
APPENDIX A
Boring Logs
Percolation Test Logs
PARTNER
Boring Number: B-1 Page 1 of 1
Location: Northwest Building Corner Date Started: 1/5/2016
Site Address: 6010 Hidden Valley Road Date Completed: 1/5/2016
Carlsbad, California Depth to Groundwater: 14 feet
Project Number: 153691.1 Field Technician: Marcus
Drill Rig Type: Hollow-stem Auger Partner Engineering and Science
Sampling Equipment: SPT 2154 Torrance Blvd, Suite 201
Borehole Diameter: 8 in Torrance, CA 90501
Depth Sample N-Value uses Description
0 Surface Cover: 12 inches of loose topsoil
1
2 I R 29 SC Fill: Dark brown, stiff, moist, clayey SAND
3 -----------------------------------------------------------------
4
s
t---~---
12 SM Brown, moist, medium dense, silty SAND ~----------------------------------------------------
6
7 I R 27 SC Brown, moist, medium dense, clayey SAND
8
9
10 I N 14 SC Alluvium: Brown, medium dense, moist to wet, clayey SAND
11
12
13
14 V Groundwater at 14 feet
15 Saturated
16
17
18
19
20 I N 14
Boring terminated at 21 feet
Groundwater measured at 14 feet upon boring completion
Boring backfilled with cement slury after completion
Boring Number: B-2 Page 1 of 2
Location: Southwest Building Corner Date Started: 1/5/2016
Site Address: 6010 Hidden Valley Road Date Completed: 1/5/2016
Carlsbad, California Depth to Groundwater: 12 feet
Project Number: 153691.1 Field Technician: Marcus
Drill Rig Type: Hollow-stem Auger Partner Engineering and Science
Sampling Equipment: SPT 2154 Torrance Blvd, Suite 201
Borehole Diameter: 8 in Torrance, CA 90501
Depth Sample N-Value uses Description
0 Surface Cover: 10 inches of topsoil
1 CL/SC Fill: Gray, firm, moist, claye SAND/Sandy CLAY and, trace roots
2
3
4
5 I R 19
6
7
8
9
10 I N 8 SC Alluvium: Brown, loose, wet to saturated, clayey SAND
11
12 V Groundwater encountered during drilling
13
14
15 I R 21 medium dense
16
17
18
19
20 I N 19
21
22
23
24
25 I N 12
26
27
28
29
continued on next 11age ...
Boring Number: B-2 Page 2 of 2
Location: Southwest Building Corner Date Started: 1/5/2016
Site Address: 6010 Hidden Valley Road Date Completed: 1/5/2016
Carlsbad, California Depth to Groundwater: 12 feet
Project Number: 153691.1 Field Technician: Marcus
Drill Rig Type: Hollow-stem Auger Partner Engineering and Science
Sampling Equipment: SPT 2154 Torrance Blvd, Suite 201
Borehole Diameter: 8in Torrance, CA 90501
Depth Sample N-Value uses Description
30 I N 13 ... continued from previous page
31 SC Brown, firm, saturated, clayey SAND
32
33
34
35 I R 38 SC Residuum: Brown, moist, dense, clayey SAND with gravel
36
37
38
39
40 I N 11 medium dense
41
42
43
44
45 I R 31 dense
46
47
48
49
so I N 25
Boring terminated at 51 feet
Groundwater measured at 12 feet upon boring completion
Boring backfilled with cement slury after completion
Boring Number: B-3 Page 1 of 1
Location: Northeast Parking Area Date Started: 1/5/2016
Site Address: 6010 Hidden Valley Road Date Completed: 1/5/2016
Carlsbad, California Depth to Groundwater: 14 feet
Project Number: 153691.1 Field Technician: Marcus
Drill Rig Type: Hollow-stem Auger Partner Engineering and Science
Sampling Equipment: SPT 2154 Torrance Blvd, Suite 201
Borehole Diameter: 8in Torrance, CA 90501
Depth Sample N-Value uses Description
0 Surface Cover: 16 inches of loose topsoil
1 SC Fill: Brown, moist, clayey SAND
------------------------------------------------------------------
2
3 CL Dark Brown, moist, sandy CLAY
4
Boring terminated at 5 feet
Boring backfilled with spoils upon completion
Groundwater not encountered
Boring Number: 8-4 Page 1 of 1
Location: Southwest Parking Area Date Started: 1/5/2016
Site Address: 6010 Hidden Valley Road Date Completed: 1/5/2016
Carlsbad, California Depth to Groundwater: 14 feet
Project Number: 153691.1 Field Technician: Marcus
Drill Rig Type: Hollow-stem Auger Partner Engineering and Science
Sampling Equipment: SPT 2154 Torrance Blvd, Suite 201
Borehole Diameter: 8in Torrance, CA 90501
Depth Sample N-Value uses Description
0 Surface Cover: 2 feet of loose topsoil
1
2 SC Fill: Brown, moist, clayey SAND
3 ~----------------------------------------------------------------
4 CL Dark brown, moist, sandy CLAY
Boring terminated at 5 feet
Boring backfilled with spoils upon completion
Groundwater not encountered
Technician: M. Marcus
Date: October-2016
Project and#: 15-153691.3 -North Coast Medical Office Building
PERCOLATION FIELD TEST REPORT
Notes & Observations
Pere Test# Pl Location: See Figure 2
Time Comments
Percolation Test -Pre Soak
Pre Soaking Time -1 or 4 Hours
Time:
Pre Soak Time:
Percolation Reading Start Time/ Elapsed WLBTP WU\ Percolation Rate for Rdg
# End Time Time (in) (in) (in/hr)
7:40 0.0
1 10 6.0 36.0 7:50 6.0
7:50 6.0 2 60 2.0 2.0 8:50 8.0
8:50 8.0
3 60 1.5 1.5 9:50 9.5
9:50 9.5
4 60 1.5 1.5 10:50 11.0
10:50 11.0 5 60 1.0 1.0 11:50 12.0
11:50 12.0
6 30 0.5 1.0 12:20 12.5
12:20 12.5 7 30 0.5 1.0 12:50 13.0
12:50 13.0
8 30 0.5 1.0 13:20 13.5
Notes:
btp -below top of pipe d 1 = Depth to Initial Water
Depth (in.)
tid = Water Level Drop of the
WL -water level Final Period or Stablixed
Rate (in)
min -minutes DIA -Diameter of the boring
(in.)
ft -feet
I weather:
Calculations
dl = 22.5
tid = 1.125
DIA= 4
Reduction Factor
Measured Percolation
rate
Deisgn Infiltration
Rate (in/hr) =
in
6.81
1.00
0.15
Page:___!_
*Measured percolation rate is the average drop of the
stabilized rate over the last 3 consecutive readings
Technician: M. Marcus Page:_!_
Date: October-2016
Project and #: 15-153691.3 -North Coast Medical Office Building
PERCOLATION FIELD TEST REPORT
Notes & Observations
PercTest # P2 Location: See Figure 2 I weather:
Time Comments
Percolation Test -Pre Soak
Pre Soaking Time -1 or 4 Hours
Time:
Pre Soak Time:
Percolation Reading Start Time/ Elapsed WLBTP WL~ Percolation Rate for Calculations # End Time Time (in) (in) Rdg lin/hrl
7:20 0.0
1 10 12.0 72.0 7:30 12.0
7:30 12.0 2 60 6.0 6.0
8:30 18.0 dl= 22.5
8:30 18.0 !1d = 1.125 3 60 2.0 2.0 9:30 20.0 DIA= 4 in
9:30 20.0
4 60 1.0 1.0 10:30 21.0
10:30 21.0
5 60 1.0 1.0 11:30 22.0
Reduction Factor 5.56 11:30 22.0
6 30 0.5 1.0
12:00 22.5 Measured Percolation 1.00
12:00 22.5 rate
7 30 0.5 1.0 12:30 23.0
12:30 23.0 Deisgn Infiltration 8 30 0.5 1.0 Rate {in[hr} = 0.18 13:00 23.5
Notes:
btp -below top of pipe d 1 = Depth to Initial Water
Depth (in.)
!1d = Water Level Drop of
WL -water level the Final Period or Stablixed •Measured percolation rate is the average drop of the
Rate (in) stabilized rate over the last 3 consecutive readings
min -minutes DIA -Diameter of the boring
(in.)
ft -feet
ATTACHMENT 1e
Category # Description i ii iii iv v vi Units
1 Drainage Basin ID or Name DMA-1 DMA-2 DMA-3 DMA-4 DMA-5 DMA-6 sq-ft
2 Design Infiltration Rate Recommended 0.100 0.100 0.100 0.100 0.100 0.100 in/hr
3 Design Capture Volume Tributary to BMP 188 239 1,409 981 322 351 cubic-feet
4 Is BMP Vegetated or Unvegetated? Vegetated Vegetated Vegetated Vegetated Vegetated Vegetated unitless
5 Is BMP Impermeably Lined or Unlined? Unlined Lined Unlined Lined Lined Lined unitless
6 Does BMP Have an Underdrain? Underdrain Underdrain Underdrain Underdrain Underdrain Underdrain unitless
7 Does BMP Utilize Standard or Specialized Media? Standard Standard Standard Standard Standard Standard unitless
8 Provided Surface Area 106 114 800 731 310 233 sq-ft
9 Provided Surface Ponding Depth 6.24 9 9 9 7 9.6 inches
10 Provided Soil Media Thickness 18 18 18 18 18 18 inches
11 Provided Gravel Thickness (Total Thickness) 27 27 21 27 15 15 inches
12 Underdrain Offset 3 3 3 3 3 3 inches
13 Diameter of Underdrain or Hydromod Orifice (Select Smallest) 0.50 0.50 0.75 0.75 0.50 0.50 inches
14 Specialized Soil Media Filtration Rate in/hr
15 Specialized Soil Media Pore Space for Retention unitless
16 Specialized Soil Media Pore Space for Biofiltration unitless
17 Specialized Gravel Media Pore Space unitless
18 Volume Infiltrated Over 6 Hour Storm 5 0 40 0 0 0 cubic-feet
19 Ponding Pore Space Available for Retention 0.00 0.00 0.00 0.00 0.00 0.00 unitless
20 Soil Media Pore Space Available for Retention 0.05 0.05 0.05 0.05 0.05 0.05 unitless
21 Gravel Pore Space Available for Retention (Above Underdrain) 0.00 0.00 0.00 0.00 0.00 0.00 unitless
22 Gravel Pore Space Available for Retention (Below Underdrain) 0.40 0.40 0.40 0.40 0.40 0.40 unitless
23 Effective Retention Depth 2.10 2.10 2.10 2.10 2.10 2.10 inches
24 Fraction of DCV Retained (Independent of Drawdown Time) 0.13 0.08 0.13 0.13 0.17 0.12 ratio
25 Calculated Retention Storage Drawdown Time 21 120 21 120 120 120 hours
26 Efficacy of Retention Processes 0.31 0.10 0.31 0.15 0.19 0.14 ratio
27 Volume Retained by BMP (Considering Drawdown Time) 58 23 432 148 61 49 cubic-feet
28 Design Capture Volume Remaining for Biofiltration 130 216 977 833 261 302 cubic-feet
29 Max Hydromod Flow Rate through Underdrain 0.0131 0.0135 0.0285 0.0303 0.0115 0.0119 cfs
30 Max Soil Filtration Rate Allowed by Underdrain Orifice 5.35 5.12 1.54 1.79 1.60 2.20 in/hr
31 Soil Media Filtration Rate per Specifications 5.00 5.00 5.00 5.00 5.00 5.00 in/hr
32 Soil Media Filtration Rate to be used for Sizing 5.00 5.00 1.54 1.79 1.60 2.20 in/hr
33 Depth Biofiltered Over 6 Hour Storm 30.00 30.00 9.23 10.75 9.61 13.22 inches
34 Ponding Pore Space Available for Biofiltration 1.00 1.00 1.00 1.00 1.00 1.00 unitless
35 Soil Media Pore Space Available for Biofiltration 0.20 0.20 0.20 0.20 0.20 0.20 unitless
36 Gravel Pore Space Available for Biofiltration (Above Underdrain) 0.40 0.40 0.40 0.40 0.40 0.40 unitless
37 Effective Depth of Biofiltration Storage 19.44 22.20 19.80 22.20 15.40 18.00 inches
38 Drawdown Time for Surface Ponding 1 2 5 5 4 4 hours
39 Drawdown Time for Effective Biofiltration Depth 4 4 12 12 10 8 hours
40 Total Depth Biofiltered 49.44 52.20 29.03 32.95 25.01 31.22 inches
41 Option 1 - Biofilter 1.50 DCV: Target Volume 195 324 1,465 1,249 391 452 cubic-feet
42 Option 1 - Provided Biofiltration Volume 195 324 1,465 1,249 391 452 cubic-feet
43 Option 2 - Store 0.75 DCV: Target Volume 98 162 733 625 195 226 cubic-feet
44 Option 2 - Provided Storage Volume 98 162 733 625 195 226 cubic-feet
45 Portion of Biofiltration Performance Standard Satisfied 1.00 1.00 1.00 1.00 1.00 1.00 ratio
46 Do Site Design Elements and BMPs Satisfy Annual Retention Requirements? - - - - - - yes/no
47 Overall Portion of Performance Standard Satisfied (BMP Efficacy Factor) 1.00 1.00 1.00 1.00 1.00 1.00 ratio
48 Deficit of Effectively Treated Stormwater 0 0 0 0 0 0 cubic-feet
No Warning Messages
False
False
Result
BMP Inputs
Retention
Calculations
Biofiltration
Calculations
Water Quality Depth Verification Calculations Water Quality Depth Verification Calculations
By: AJV By: AJV
Date: 6/2/2025 Date: 6/2/2025
DMA-1BMP-A DMA-2BMP-B
Area of FS of Basin 28.68 sqft Area of FS of Basin 114 sqft
Area of WQ Elevation of Basin 99 sqft Area of WQ Elevation of Basin 114 sqft
Ponding from FS to WQE (H)0.8066 ft Ponding from FS to WQE (H)0.75 ft
Volume Needed 51.493344 cuft Volume Needed 85.5 cuft
Re adjusted H for basin Re adjusted H for basin
Area'99 sqft Area'114 sqft
0.52013479 ft 0.75 ft
6.24161745 in 9 in
Has Mulch? Yes, NO NO Has Mulch? Yes, NO NO
No Mulch, No Modification 6.24161745 in No Mulch, No Modification 9 in
In Compliance? (Yes, No)Yes In Compliance? (Yes, No)Yes
Water Quality Depth Verification Calculations Water Quality Depth Verification Calculations
By: AJV By: AJV
Date: 6/2/2025 Date: 6/2/2025
DMA-5BMP-E DMA-6BMP-F
Area of FS of Basin 126 sqft Area of FS of Basin 88.26 sqft
Area of WQ Elevation of Basin 310.34 sqft Area of WQ Elevation of Basin 233.17 sqft
Ponding from FS to WQE (H)0.8333 ft Ponding from FS to WQE (H)1.417 ft
Volume Needed 181.801061 cuft Volume Needed 227.733155 cuft
Re adjusted H for basin Re adjusted H for basin
Area'310.34 sqft Area'233.17 sqft
0.58581253 ft 0.97668291 ft
7.02975038 in 11.720195 in
Has Mulch? Yes, NO NO Has Mulch? Yes, NO NO
No Mulch, No Modification 7.02975038 in No Mulch, No Modification 11.720195 in
In Compliance? (Yes, No)Yes In Compliance? (Yes, No)Yes
BMP-A BMP-B
H' Actual water quality height H' Actual water quality height
BMP-E BMP-F
H' Actual water quality height H' Actual water quality height
I l
I 1 I 1
398 Via El Centro, Oceanside, CA 92058
(760) 433-7640 • Fax (760) 433-3176
www.biocleanenvironmental.com
October 21, 2021
Mr. Leo Cosentini
California State Water Resources Control Board
Division of Water Quality
P.O. Box 100
Sacramento, CA 95812-100
Re: Amended Application for Trash Treatment Control Device - Bio Clean® Grate Inlet
and Curb Inlet Filters
Dear Mr. Cosentini,
Bio Clean® is pleased to re-submit this application for the Grate Inlet and Curb Inlet Filters for
Certification as a Full Capture System - Trash Treatment Control Device. The Bio Clean® Grate
Inlet and Curb Inlet Filters have been approved since February 2021 when originally submitted
to the California State Water Resources Control Board. Recently, additional configurations have
been added to the device. We've also removed our smallest size filter to remain compliant with
MVCAC vector control regulation. Additional configuration sizes, concept drawings, photos,
and hydraulic calculations have been added to the end of this amended application and are all
included in Appendix I. Documentation for this application is being submitted in accordance
with the California State Water Resources Control Board Trash Treatment Control Device
Application Requirements document that includes the following minimum requisite sections:
1.Cover Letter
2.Table of Contents
3.Physical Description
4.Installation Guidance
5.Operation and Maintenance Information
6.Vector Control Accessibility
7.Reliability Information
8.Field/Lab Testing Information and Analysis
Please contact me with any questions or should additional information be required. Thank
you for your consideration of this application.
Regards,
Jacob Forst
Product Research and Development Technician
Bio Clean®, A Forterra Company
Bio ~Clean
A Forterra Company
2
1.0 COVER LETTER
1.A. Device product name and general description;
The Bio Clean® Grate Inlet and Curb Inlet Filters are designed to capture trash and debris. The
Grate Inlet and Curb Inlet Filters are passive, gravity flow devices and can be installed as a new
construction BMP or retrofit BMP into standard storm drain inlets to treat flows after
interception but prior to conveyance. The design incorporates a non-blocking screen that has an
aperture less than 5mm ensuring capture of all particles 5mm in size or larger. Each device also
incorporates an integrated internal bypass feature ensuring captured pollutants to not impede
interception or conveyance of peak storm water runoff.
These Devices are fabricated from rigid, durable materials such as stainless steel and marine
grade fiberglass. Installation is quick and easy with the design requiring minimal to no mounting
hardware. Routine maintenance is required to remove pollutants and is site and pollutant loading
dependent. Maintenance is facilitated by the unique design of the device allowing for direct
access of the Filters through the manhole access and/or grate.
1.B. The name of the Device owner;
California Contact:
Sean Hasan
Western Region Director
Bio Clean®, A Forterra Company
398 Via El Centro
Oceanside, California 92058
(760) 283-7188
Sean.Hasan@forterrabp.com
Corporate Contact:
Stephen Hides
VP & General Manager
Bio Clean®, A Forterra Company
511 East John Carpenter Freeway
Irving, Texas 75062
(760) 517-9030
Stephen.Hides@forterrabp.com
3
1.C. The owner or manufacturer’s website where the Device can be found on
the internet;
The Bio Clean® Grate Inlet and Curb Inlet Filters can be found on the Bio Clean® website:
www.biocleanenvironmental.com/catch-basin-inlet-filters
1.D. The location of the Device manufacturing site;
The Bio Clean® stormwater division is supported through manufacturing by its parent company
Forterra Building Products. Forterra Building Products currently has 88 manufacturing locations
throughout the country. Three facilities currently provide support for the California market and
are listed below:
Forterra Building Products
Drainage Pipe and Products Division
7020 Tokay Avenue
Sacramento, California 95828
Forterra Building Products
Drainage Pipe and Products Division
26380 Palomar Road
Menifee, California 92585
Forterra Building Products
Bio Clean® Stormwater Management Systems
398 Via El Centro
Oceanside, California 92058
1.E. A brief summary of any field/lab testing results that demonstrates the
device functions as described within the application;
Bio Clean® conducted laboratory testing on the proprietary non-blocking screen material utilized
in the Grate Inlet and Curb Inlet Filters. Bio Clean® conducted this testing to empirically
determine unique properties of the screen including the Effective Open Area (EOA), the
Coefficient of Discharge (Cd), and the flow capacity and characteristics. The results of the testing
provided a clear relationship between discharge (Q) and head (h) acting on the screen. The
results of the testing have been incorporated into the design of the Filters to determine both the
treatment and peak flow rates for the Filters.
The test report has been included in the Application as Appendix F for review by the SWRCB
and interested parties.
4
1.F. A brief summary of the device limitations, and operational sizing, and
maintenance considerations;
The Bio Clean® Grate Inlet and Curb Inlet Filters are pre-engineered filtration systems designed
to meet site-specific water quality treatment requirements. Conformance with the Engineer’s
Plans and Specifications and the Manufacturer’s recommendations is essential to ensure proper
operation and function of the Device.
Bio Clean® manufactures the Grate Inlet and Curb Inlet Filters using stainless steel and marine
grade fiberglass components. The materials selected serve a wide variety of applications and are
the most durable materials available for these type devices. Adherence to installation
recommendations are required to ensure the design service life of the Device is maintained.
Bio Clean® Grate Inlet and Curb Inlet Filters should be sized to meet site and region specific
water quality objectives and requirements. Systems that are not designed and installed in
conformance within the maximum treatment flow rate and maximum bypass flow rate limits can
cause adverse hydraulic conditions. Additionally, non-conformance with the Device design
limits may cause non-compliance with the Trash Provisions.
All structural, post-construction Best Management Practices require routine and scheduled
inspection and maintenance. Inspection and maintenance is facilitated by the design of the
Device. The design of the Device allows for placement of the Filters directly beneath the grate
and/or manhole access allowing direct, unimpeded access to the storage baskets for quick and
easy removal with no confined space entry required. Design considerations for maintenance
frequency should be a consideration.
1.G. A description or list of locations, if any, where the device has been
installed. Include the name and contact information of as many as three
municipality(s) purchasing the Device; and
Installations of the Trash Capture version of this device are pending SWRCB Certification.
1.H. The application shall be signed by the owner or authorized
representative (not the technical or sales representative) and include the
following certification:
I certify under penalty of law that this document and all attachments were prepared under my
direction or supervision in accordance with a system designed to assure that qualified personnel
properly gather and evaluate the information submitted. Based on my inquiry of the person or
persons that manage the system or those persons directly responsible for gathering the
information, to the best of my knowledge and belief, the information submitted is, true, accurate,
6
THIS PAGE INTENTIONALLY LEFT BLANK
5
and complete. I am aware that there are significant penalties for submitting false information,
including the possibility of fine and imprisonment for knowing violations.
________________________________________________ __________________
Stephen Hides, Vice President and General Manager Date
3-5-2021
7
2.0 TABLE OF CONTENTS
Contents
1.0 COVER LETTER ..............................................................................................................2
1.A. Device product name and general description; ....................................................................2
1.B. The name of the Device owner; ...........................................................................................2
1.C. The owner or manufacturer’s website where the Device can be found on the internet; ......3
1.D. The location of the Device manufacturing site; ...................................................................3
1.E. A brief summary of any field/lab testing results that demonstrates the Device functions as
described within the application; .........................................................................................3
1.F. A brief summary of the Device limitations, and operational, sizing, and maintenance
considerations; .....................................................................................................................4
1.G. A description or list of locations, if any, where the Device has been installed. Include the
name and contact information of as many as three municipality(s) purchasing the Device;
and ........................................................................................................................................4
1.H. The application shall be signed by the owner or authorized representative (not the
technical or sales representative) and include the following certification. ..........................4
2.0 TABLE OF CONTENTS ..................................................................................................7
3.0 PHYSICAL DESCRIPTION ..........................................................................................10
3.A. Trash Capture: Describe how the Device traps all trash particles 5mm or greater in
size; ....................................................................................................................................10
3.B. Peak Flows/Trash Volumes: Explain how the Device is sized for varying peak flow
rates and trash capture volumes; ........................................................................................10
3.C. Hydraulic Capacity: For all standard sizes, provide a table of the hydraulic capacity
(flow rate) when the Device is empty and at several intervals of trash capture volumes up
to the Device’s recommended maximum trash capture volume; .......................................18
3.D. Comparison Table: For all standard sizes, provide a table that includes the peak flow
rates, and recommended maximum trash capture volume; ................................................20
3.E. Design Drawings: Provide design drawings for all standard Device sizes and, if any,
alternative configurations; .................................................................................................20
3.F. Alternative Configurations: If the Device includes alternative configurations, explain
the purpose of each configuration and mandatory installation conditions; .......................21
3.G. Internal Bypass: If the Device has an internal bypass, explain how the bypass functions
to only allow a bypass of flows exceeding the peak flow rate; .........................................21
8
3.H. Previously Trapped Trash: Explain the condition(s) under which the Device re-
introduces previously trapped trash (e.g., via the internal bypass); ...................................23
3.I. Calibration Feature: If the Device includes an adjustable calibration feature, describe
how the calibration feature functions;................................................................................24
3.J. Photos: If any, provide Device installation photographs; .................................................24
3.K. Material Type: Provide each material and material grade used to construct the Device
(e.g., stainless steel, plastic, etc.); and ...............................................................................26
3.L. Design Life: Provide the estimated design life..................................................................27
4.0 INSTALLATION GUIDANCE ......................................................................................27
4.A. Standard Device installation procedures including calibration instructions if
applicable; ..........................................................................................................................27
4.B. Description of Device installation limitations and/or non-standard Device installation
procedures; and ..................................................................................................................28
4.C. Methods for diagnosing and correcting installation errors ................................................28
5.0 OPERATION AND MAINTENANCE INFORMATION ...........................................29
5.A. Inspection procedures and frequency considerations; .......................................................29
5.B. Description of maintenance frequency considerations related to the Device’s hydraulic
capacity at various levels of trash capture volumes; ..........................................................30
5.C. Maintenance procedures, including procedures to clean the trash capture screen; ...........30
5.D. Essential equipment and materials for proper maintenance activities; ..............................31
5.E. Description of the effects of deferred maintenance on Device structural integrity,
performance, odors, etc.; and .............................................................................................32
5.F. Repair procedures for the Device’s structural and screening components ........................32
6.0 VECTOR CONTROL ACCESSIBILITY .....................................................................32
6.A. The date the Device application was submitted for vector control accessibility design
verification via email to the Mosquito Vector Control Association of California
(MVCAC) (Trashtreatment@mvcac.org); .........................................................................32
6.B. Description and/or video that demonstrates how mosquito vector control personnel can
readily access the bottom of the storm water vault and/or Device for visual observation
and mosquito treatment; and ..............................................................................................33
6.C. The MVCAC Letter of Verification as an attachment to the application when it becomes
available. This letter shall verify that the Device design allows full visual access for
presence of standing water and treatment of mosquitoes when necessary. Table of
contents shall note the MVCAC approval letter ................................................................37
7.0 RELIABILITY INFORMATION ..................................................................................37
7.A. Estimated design life of Device components before major overhaul; ...............................37
9
7.B. Warranty Information; and ................................................................................................37
7.C. Customer support information ...........................................................................................37
8.0 FIELD/LAB TESTING INFORMATION AND ANALYSIS .....................................38
8.A. For Devices with 5mm screening, any available field/lab testing information that
demonstrates the Device functionality and performance; and ...........................................38
8.B. If the Device does not include a 5mm screen, adequate field/lab testing information that
demonstrates the Device captures trash particles of 5mm or greater; ...............................38
APPENDIX A – Design Drawings ................................................................................................39
APPENDIX B – Specifications .....................................................................................................44
APPENDIX C – Installation Manuals ...........................................................................................56
APPENDIX D – Operation and Maintenance Manuals .................................................................85
APPENDIX E – Warranty ...........................................................................................................102
APPENDIX F – Field/Lab Testing Data .....................................................................................104
APPENDIX G – MVCAC Verification Letter ............................................................................110
APPENDIX H – Sample Hydraulic Calculations ........................................................................112
APPENDIX I – Alternate Configuration Documentation ...........................................................117
10
3.0 PHYSICAL DESCRIPTION
3.A. Trash Capture: Describe how the Device traps all trash particles 5 mm
or greater in size;
The Bio Clean® Grate Inlet and Curb Inlet Filters are passive, gravity flow, stormwater
treatment systems utilizing screening, sedimentation, and absorption to capture trash, floating
and neutrally buoyant debris, suspended sediments and hydrocarbons. The non-blocking
screening system is suspended from either the grate or at the curb inlet opening and retains the
captured pollutants above the bottom of the catch basin allowing the captured trash and debris to
be stored in a dry state that prevents further contamination of the stormwater and minimizes
maintenance requirements. Design flows are directly routed through a basket made from non-
blocking, stainless steel screen that has an aperture not greater than 4.7 mm ensuring capture of
all particles 5mm in size or larger.
The Bio Clean® Grate and Curb Inlet Filters incorporate the following features to achieve full
capture of all particles larger than 5mm. These features additionally ensure no re-suspension of
previously captured pollutants.
• The pollutant capture basket sidewall is manufactured from a proprietary, non-blocking
louver-expanded stainless steel screen. The openings of the screen are made by a process
that angles the opening in one direction so that when water and debris encounter the
screen a wiping action occurs which pushes both water and debris across the opening
rather than through the opening. This perpetual, deflective shielding action minimizes
blockages and penetration of debris through the screen opening.
• The proprietary, non-blocking screens are made from 20-gauge, type 304 stainless steel
with an aperture not greater than 4.7mm. The open area is not less than 37%.
• The pollutant capture basket bottom screen is manufactured from 14-gauge, type 304
stainless steel with an aperture not greater than 5.0mm. The open area is not less than
51%.
• Bypass features are incorporated in all Devices and are located above the treatment water
level in the basket ensuring retention of all trash and debris for flows conforming to full
capture requirements.
3.B. Peak Flows/Trash Volumes: Explain how the device is sized for varying
peak flow rates and trash capture volumes;
Grate Inlet Filter Operation & Sizing
Stormwater flowing from parking lots and roads begin their entrance into the catch basin through
the grated inlet. Prior to entering the catch basin, the flows must first pass through the Grate Inlet
11
Filter. The Grate Inlet Filter installs directly beneath the grate of the catch basin and all flow that
enters the catch basin are first directed through the Filter (See Figure 2 – Grate Inlet Filter
Operation).
The Inlet Filter is straightforward in design, but special consideration was given to the
configuration and capacities to ensure maximum possible treatment and adequate bypass without
re-suspension of previously removed pollutants (See Figure 1 – Grate Inlet Filter Features). The
sidewall of the filter basket is constructed from a proprietary, non-blocking, louver-expanded
stainless steel screen. The openings of the screen are made by a process that angles the opening
in one direction so that when water and debris encounter the screen, a wiping action occurs
which pushes both water and debris across the opening rather than through the opening. This
perpetual, deflective shielding action minimizes blockages and penetration of debris through the
screen opening. Once flows are filtered, the stormwater enters the catch basin and is allowed to
freely exit through the lateral pipe.
During peak flow events, the Inlet filter continues to treat, however water levels in the filter
basket may rise to the point of overflow, at which point the Inlet Filter is considered to be
operating in bypass mode. Bypass occurs through a circumferential opening (or window) at the
top of the basket just above the filter screen but beneath the grate. During smaller peak flow
events, the bypass window operates as a weir allowing these flows to exit through the bottom of
the window. A significant amount of flow continues to be filtered, and this continued flow forces
previously retained pollutants to remain in the filter basket. During larger peak flow events, the
water level will rise above the bypass window changing the window to act like an orifice. Peak
flows are discharged through the window with the orifice controlling flow.
The Engineer should make note of the treatment flow capacity, the bypass flow capacity, as well
as the grate inlet flow capacity and determine which of the three may be a limitation of the flow
capacity for this component of the storm drain system.
A sizing chart for the Grate Inlet Filter is shown in Table 1. The nomenclature for models lists
the Width x Length x Height of the grate and filter basket. The characteristics and capacity Table
lists the maximum treatment capacity for Full Capture trash removal. The Table additionally lists
the maximum storage capacity (for trash and sediment). These capacities are considerate of both
re=suspension of removed pollutants and screen blocking. A safety factor has been applied to the
storage capacity, treatment capacity, and bypass capacity. The Table lists the most commonly
utilized standard sizes available. Other standard sizes are available as well as custom
configurations. Characteristics and capacities will be determined on an as needed basis following
the same guidelines and using the same empirically determined data for sizing of the custom
configurations.
12
High Flow
Bypass
Grate Inlet Filter F eatnres
Figure 1 • Grote Jnfet Fitter Features
13
Grate Inlet Filter Operation -Diagram
Treatment Flow Bypass Flow I
Bypass Flow
Figure 2 • Grate Inlet Filrer Operation
14
1. Other standard and custom model sizes available. Contact Bio Clean® for more information.
2. Storage Capacity based on the basket half full.
3. Considers a Safety Factor of 2.0 for side discharge and a Safety Factor of 3.0 for bottom discharge.
4. Considers a local depression ponding depth of 6-inches and a grate thickness of 3.5-inches.
5. In some cases, the filtered flow capacity has been reduced to the maximum possible inflow to the filter.
6. In some cases, the bypass capacity has been reduced to the maximum possible inflow to the filter.
Curb Inlet Filter Operation & Sizing
The Curb Inlet version of the Device functions very similarly to the Grate Inlet version in terms
of physical filtration. Both Devices utilize the same cylindrical basket for physical filtration of
the stormwater. The two Devices differ in how stormwater flow is received and conveyed to the
filter and how peak flows bypass the filter (See Figure 3 – Curb Inlet Filter Features).
Stormwater flowing from parking lots and roads begin their entrance into the catch basin through
a curb opening. The opening may be as short as two feet long or as long as 28 feet long. In a
typical curb inlet, these flows would be allowed to drop to the bottom of the catch basin and
freely exit the basin. To treat for Trash Full Capture, the inlet is outfitted with a trough made
from marine grade fiberglass. The trough is mounted directly beneath the curb opening and spans
the entire length of the opening. The trough collects all low flows entering the catch basin and
conveys and directs the water to the filter. The filter is connected to the trough by a square tray
system. The tray provides a physical and hydraulic connection between the trough and the filter.
Additionally, the tray positions the filter back away from the curb opening. This position is an
adequate distance away from the curb opening to remove the filter from the influence of peak
flows. Furthermore, the tray positions the filter basket directly beneath the manhole access cover
to provide for quick and easy removal of trash, debris and sediment without the need to enter the
catch basin.
The filter basket is similarly constructed to the Grate Inlet Filter with the exception of the bypass
window. The filter basket operates the same during filtration of the stormwater. The bypass
window is omitted from the filter basket of the Curb Inlet Filter and bypass occurs upstream in
Bio Clean® Grate Inlet Filter Characteristics and Capacity Table
California Full Capture Certified Capacities
TABLE 1
Filter Filter 50% Storage Treatment Basket Basket Model No.1
Diameter Height Capacity2 Capacity3,5
(in) (in) (ft') (ft3/s)
BC-G-1 2-1 2-12 10 12 0.27 1.5 5
BC-G-1 8-1 8-1 8 16 18 1.05 4.32
BC-G-24-24-24 21 24 2.41 7.67
BC-G-30-30-24 27 24 3.98 12.97
BC-G-25-38-24 33 X 21 24 4.16 13 .53
BC-G-36-36-24 33 24 5.94 19.64
BC-G-48-48-1 8 44 18 7.92 25.59
Bypass
Capacity4,6
(ft3/s)
1.55
3.68
4.83
6.21
6.59
7.60
10.13
15
the trough system. The trough is designed such that the height of the trough is less than the
height of the filter tray system. The trough height has adequate capacity to collect and convey
treatment flows to the filter. Peak flows exceed the capacity of the trough system and overtop the
height of the trough. Because bypass occurs upstream of the filter, peak flows are kept separate
from the treatment area and re-suspension of pollutants does not occur. Because the Curb Inlet
Filter bypass operation is the same as the standard curb inlet operation, the bypass capacity of the
filter is the same as the standard inlet capacity of the curb opening (See Figure 4 – Curb Inlet
Filter Operation).
A sizing chart for the Curb Inlet Filter is shown in Table 2. The treatment basket diameter is the
same for all models. The variable dimension between models is the filter basket height and this is
noted n the nomenclature for the models with the last digits of the model number. The
characteristics and capacity Table lists the maximum treatment capacity for Full Capture Trash
removal. The Table additionally lists the maximum storage capacity (for trash and sediment).
These capacities are considerate of both re-suspension of removed pollutants and screen
blocking. A safety factor has been applied to the storage capacity and treatment capacity. The
Table includes the most commonly utilized standard sizes available. Other standard sizes are
available as well as custom configurations. Characteristics and capacities will be determined on
an as needed basis following the same guidelines and using the same empirically determined data
for sizing of the custom configurations.
16
Curb Inlet Filter Features
fjgure 3 • Curb Inlet Fiher Features
17
Curb Inlet Filter Operation -Diagram
Treatment Flow I Bypass Flow I
Figure 4 + Curb Inlet Filter in Bypass Operation
18
1. Other standard and custom model sizes available. Contact Bio Clean® for more information. 2. Storage Capacity based on the basket half full.
3. Considers a Safety Factor of 2.0 for side discharge and a Safety Factor of 3.0 for bottom discharge.
4. In some cases the filtered flow capacity has been reduced to the maximum possible inflow to the filter.
3.C. Hydraulic Capacity: For all standard sizes, provide a table of the
hydraulic capacity (flow rate) when the Device is empty and at several
intervals of trash capture volumes up to the Device’s recommended maximum
trash capture volume;
Table 1 and Table 2 above list the trash capture volume (ft3) retained by each Inlet Filter model.
The trash capture volumes listed are maximum volumes that can be removed without a reduction
in treatment performance and considers full retention of trash with no re-entrainment under peak
flow conditions. Table 3 and Table 4 list the hydraulic capacities of each Device at various levels
of trash capture volume. Sample calculations for the hydraulic flow for the Curb and Grate Inlet
Filters can be found in Appendix H.
Bio Clean® Curb Inlet Filter Charncteristics and Capacity Table
California Full Capture Certified Capacities
TABLE2
Filter Basket Filter Basket 50% Storage Treatment Model No.1
Diameter (in) Heie:ht (in) Capacity2 (ft3) Capacity3,4 (ft3/s)
BC-CURB-30 18 30 2.21 2.85
BC-CURB-24 18 24 1.77 2.85
BC-CURB-1 8 18 18 1.33 2.85
BC-CURB-12 18 12 0.88 2.85
19
1. Other standard and custom model sizes available. Contact Bio Clean® for more information.
2. Based on 37% Open Area.
3. Based on 51% Open Area.
4. Considers a Safety Factor of 2.0 for side discharge and a Safety Factor of 3.0 for bottom discharge.
5. Considers a local depression ponding depth of 6-inches and a grate thickness of 3.5-inches.
6. Storage Capacity based on the basket half full.
7. In some cases the filtered flow capacity has been reduced to the maximum possible inflow to the filter.
8. In some cases the bypass capacity has been reduced to the maximum possible inflow to the filter.
Bio Clean® Grate Inlet Filter Hydraulic Capacities at
Various levels of t r ash capture volumes
TABLE 3
GRATED INLETS
Filtered Filtered Filtered
Flow Flow Flow Bypass
Filtered
Capacity4 Capacity4 Capacity4 Flow
Model1 Flow Capacity5
Capacity4 25% 50% 75% 100% Clogging Clogging Clogging Clogged Factor Factor Factor
(ft3 /s) (ft3 /s) (ft3 /s) (ft3 /s) (ft3 /s)
BC-G-12-12-12 1.55 1.55 0.97 0.46 1.55
BC-G-18-18-18 4.32 4.32 2.91 1.39 3.68
BC-G-24-24-24 7.67 7.67 5.84 2.78 4.83
BC-G-30-30-24 12.97 12.97 8.26 4.11 6.21
BC-G-36-36-24 19.64 17.14 11.01 5.67 7.60
BC-G-48-48-18 25.59 18.99 12.91 7.30 10.13
BC-G-25-38-24 13.53 13.53 12.08 6.71 6.59
Solids
Storage
Capacity6
(ft3)
0.27
1.05
2.41
3.98
5.94
7.92
4.16
20
1. Other standard and custom model sizes available. Contact Bio Clean® for more information. 2. Based on 37% Open Area.
3. Based on 51% Open Area.
4. Considers a Safety Factor of 2.0 for side discharge and a Safety Factor of 3.0 for bottom discharge.
5. Storage capacity based on the basket half full.
6. In some cases the filtered flow capacity has been reduced to the maximum possible inflow to the filter.
3.D. Comparison Table: For all standard sizes, provide a table that includes
the peak flow rates, and recommended maximum trash capture volume;
Maximum trash capture volume and hydraulic capacities are listed in Table 1 and Table 3 for
Grate Inlet Filters, as well as Table 2 and Table 4 for Curb Inlet Filters.
3.E. Design Drawings: Provide design drawings for all standard Device sizes
and, if any, alternate configurations;
Design drawings for all standard devices and configurations are included in Appendix A.
Bio Clean® Curb Inlet Filter Hydraulic Capacities at
Various L evels of Trash Capture Volumes
TABLE 4
CURB INLETS
Filtered Filtered Filtered
Filtered Flow Flow Flow Solids
Capacity4 Capacity4 Capacity4
1 Flow Storage Model
Capacity4 25% 50% 75% Capacity6
Clogging Clogging Clogging
Factor Factor Factor
{ft3 /s) {ft3 /s) {ft3 /s) {ft3 /s) (ft3)
BC-CURB-24 2.85 2.85 2.85 2.85 1.40
BC-CURB-18 2.85 2.85 2.85 2.85 1.05
BC-CURB-12 2.85 2.85 2.85 2.85 0.70
21
3.F. Alternative Configurations: If the Device includes alternative
configurations, explain the purpose of each configuration and mandatory
installation conditions;
As of this amended application, there is an alternative configuration to the Grate Inlet Filter. The
filter basket itself is going from cylindrical in shape to a tapered square shape so that these
baskets can be nested into each other during shipping. The top flange and bypass components
remain the same, and the system operates the same as the standard configuration, from the
treatment flow path to the bypass flow path. This alternative configuration is also installed in the
same way as the standard configuration. Additional concept drawings, photos, and hydraulic
calcs for this alternative configuration have been added to the end of this application in
Appendix I.
3.G. Internal Bypass: If the Device has an internal bypass, explain how the
bypass functions to only allow a bypass of flows exceeding the peak flow rate;
The Grate Inlet and Curb Inlet Filters are designed to capture target pollutants of concern but the
Devices have also been designed to not impede normal hydraulic operation of the catch basins
they are installed in. This is accomplished by way of an internal bypass feature of the basket for
the Grate Inlet Filter and the weir tray for the Curb Inlet Filter. These bypass features are
incorporated into the Device before the retained trash and treatment area and therefore do not
release previously retained pollutants.
Grate Inlet Filter Bypass Operation
During peak flow events, the Grate Inlet Filter continues to treat, however water levels in the
filter basket may rise to the point of overflow at which point the Inlet Filter is considered to be
operating in bypass mode. Bypass occurs through a circumferential opening (or window) at the
top of the basket just above the filter screen but beneath the grate (See Figure 5). During smaller
peak flow events, the bypass window operates as a weir allowing these flows to exit through the
bottom of the window. A significant amount of flow continues to be filtered and this continued
flow forces previously retained pollutants to remain in the filter basket. During larger peak flow
events, the water level will rise above the bypass window changing the window to act like an
orifice. Peak flows are discharged through the window with the orifice controlling the flow.
The bypass flows continue to convey between the exterior of the filter basket and the interior of
the catch basin. The bypass flow and treated flow rejoin prior to exiting the catch basin.
Adequate annular space is required for these bypass flows to continue unimpeded and at a
capacity not less than originally intended for the catch basin. The bypass flow rates for each filter
basket configuration has been pre-determined and are published in Table 1. This bypass flow
rate should be noted and compared to the original design capacity of the catch basin. A safety
factor has been applied to the bypass capacity.
22
Section 3.G. (Continued)
Curb Inlet Filter Bypass Operation
The filter basket for the Curb Inlet is similarly constructed to the Grate Inlet Filter basket with
the exception of the bypass window. Both filter baskets operate the same during filtration of
stormwater. The bypass window is omitted from the filter basket of the Curb Inlet Filter and
bypass occurs upstream in the trough system (See Figure 6). The trough is designed such that the
height of the trough is less than the height of the filter tray system. The trough height has
adequate capacity to collect and convey treatment flows to the filter basket. Peak flows exceed
the capacity of the trough system and overtop the height of the trough. Because bypass occurs
upstream of the filter, peak flows are kept separate from the treatment area and re-suspension of
pollutants does not occur. Because the filter bypass operation is the same as the standard curb
inlet operation, the bypass capacity of the filter is the same as the standard inlet capacity of the
curb opening.
Bypass Flow
Byll)aiss W indow
figu,-e 5 -Grate In.let Filter in Bypass Operation
23
3.H. Previously Trapped Trash: Explain the condition(s) under which the
Device re-introduces previously trapped trash (e.g., via the internal bypass);
The Grate Inlet and Curb Inlet Filters have been designed to remove and permanently retain all
trash and debris that is 5mm in size or larger. Conditions under which either configuration of the
Device re-introduce previously trapped trash are listed below:
• If the Device is not properly maintained and trash and debris are allowed to accumulate
beyond the prescribed maximum allowable level in the trash containment compartments,
conditions will be present that could cause a re-introduction of trash into the effluent of
the Device.
• Broken or damaged screens, baskets or troughs can cause an adverse condition that would
allow re-introduction of trash and debris into the effluent.
• Missing or un-replaced components after a maintenance service can cause an adverse
condition that could re-introduce trash and debris into the effluent of the Device.
Bypass Flow
Figuu 6 ~ curb 1nf1t Fitter in Syptm op,ratioll
24
3.I. Calibration Feature: If the Device includes an adjustable calibration
feature, describe how the calibration feature functions;
The Grate Inlet and Curb Inlet Filters do not have any adjustable calibration features.
3.J. Photos: If any, provide device installation photographs;
Figure 7 -Grate Inlet Filter (no aae.s.s indowJ Priar to trutallation. Fig11re 8 -Grote Inlet Filter (no acce.s.s window) Being lliStalled.
Figure 9 -Grote Inlet Filter (no access window) Being Installed. figure 10 -Grate Inlet Filter (no access wind(YMIJ Being Installed.
figure .u -Grote Inlet Filter (no access window} Installed. Figure J:2 -Grote Ill.let fl.lter (no acce:S:s-window} Prior to Ma· renance.
25
Section 3.J. (Continued)
Figure 13 • Grore mfet. Fifter {no access wjndow) Priorro Moinrenonce. Figure 14 • Grote Inlet Fifter (no access window)lnsralled After Mainrenonce.
Figure 15. Grore 1111.er Fifter (no access window) mstolled After Mointenance. Figure 16. curb Jnlet Filter Bask er Being lnsto/Jed.
f#Jf.'n J 7. Curb twt Filtn aoskrt &i'ng mtolfd. hgure JB. Curb lnkt Filtv &1.sbt aerng tnsta/W.
26
Section 3.J. (Continued)
3.K. Material Type: Provide each material and material grade used to
construct the Device (e.g., stainless steel, plastic, etc.); and
The Grate Inlet and Curb Inlet Filters are constructed of high strength, durable materials and
components that ensure a long design and service life for the Device. Appendix B of this
submittal includes a detailed Specification for the Grate Inlet and Curb Inlet Filters which
includes material Specifications. Key materials and components are additionally listed below:
• Filter Housing – The Filter Housing is manufactured from Type 304 Stainless Steel.
• Side Screens – The Side Screen is manufactured from Type 304 Stainless Steel, louver-
expanded metal with openings equal to or less than 4.7mm in size.
• Bottom Screens – The Bottom Screens are manufactured from Type 304 Stainless Steel,
perforated mesh, with round openings equal to or less than 5mm in size.
• Media Filtration Booms (Optional) – The Media Booms are made from granulated oil
absorbing polymers tested in accordance with ASTM F 716.07
• Trough – The Trough is manufactured from marine grade fiberglass and Type 304
Stainless Steel.
• Weir – The weir box is manufactured from Type 304 Stainless Steel.
Figure 1.9 -cu,t, JrJ/et Fi/re~ 11o.s1et mstaIJe.d r11 Troy S)'stem. Figure 2C -curb Inlet Filter 11askf't mstalled In Tray system.
Figure· 21 -cu,t, JrJ/et f:ilr~ 11o.s1et installed Jn mw system.
27
3.L. Design Life: Provide the estimated design life.
The estimated design life for the Grate Inlet and Curb Inlet systems is 25 to 50 years. The design
life is dependent on the materials is utilized as well as the proper application of those materials.
4.0 INSTALLATION GUIDANCE
4.A. Standard device installation procedures including calibration
instructions if applicable;
Installation requirements and procedures for the Grate Inlet Filter and Curb Inlet Filter are
detailed in the Grate Inlet Filter Installation Manual and Curb Inlet Filter Installation Manual
which have been included in Appendix C of this submittal. The guidelines include requirements
and procedures for:
• Delivery
• Inspection
• Cath Basin Preparation
• Installation
• Installation Diagrams
Grate Inlet Filter Installation
The Grate Inlet Filter requires minimal tools and effort for a successful installation. The most
critical part of the installation is measurement of the catch basin and grate dimensions. Proper
measurements ensures proper manufacture of the Inlet Filter and provides an opportunity to
check the Device will function properly with no adverse effects to the existing storm drain
system. Measurement charts for the Grate Inlet Filter are included as part of this submittal at the
end of Appendix C.
Once the measurements have been completed, the Inlet Filter is manufactured and delivered for
installation. Most installations require only removing the catch basin grate, cleaning the catch
basin, lowering the Inlet Filter into position, and then replacing the grate. Some versions of the
Inlet Filter require installation of a secondary support structure within the catch basin. Details of
this type of installation and the standard installation can be found in Appendix C.
Curb Inlet Filter Installation
The Curb Inlet Filter system utilizes several components in addition to the filter basket and
requires mounting some of the components to the inside walls of the catch basin. As with the
28
Grate Inlet Filter, the most critical part of the installation is measurement of the catch basin.
Proper measurement ensures proper manufacture of the Inlet Filter and provides an opportunity
to check the Device will function properly with no adverse effects to the existing storm drain
system. Measurement charts for the Curb inlet Filter are included as part of this submittal at the
end of Appendix C.
Additionally, confined space entry of the catch basin is likely required for the primary
installation of the Curb Inlet Filter system. It is imperative the installer adhere to all jurisdictional
and/or OSHA safety recommendations and requirements.
Post installation inspection of the Inlet Filters is strongly advised. A representative from Bio
Clean® is available for on-site inspection as support for the Owner. Inspection should determine
if the Inlet Filter was installed properly as well as provided in a clean condition with no defects
as a result of the installation.
Installation for Trash Capture in association with Full Capture programs, Trash TMDLs, or the
Statewide Trash Amendment are often retrofit type installations. Care should be taken to
document existing and as-built conditions to determine if the Inlet Filters must be supplied in a
unique configuration to meet the retrofit conditions. Consideration must be given to any unique
configurations for flow, treatment, and installation.
4.B. Description of device installation limitations and/or non-standard device
installation procedures; and
Aside from confined space requirements and/or other OSHA safety recommendations, there are
no additional limitations on the installation of the Grate Inlet and Curb Inlet Filters.
4.C. Methods for diagnosing and correcting installation errors.
Bio Clean® has a process for design and manufacturer that includes checks and balances to
minimize and eliminate errors in the design and manufacturing processes for the Grate Inlet and
Curb Inlet systems. This process involves a formal submittal and review of the design and
fabrication details for each unit. The owner has and should take this opportunity to review the
proposed device prior to installation. This process helps to reduce or eliminate errors during
installation. In the event an installation error does occur, the error should be documented and
reviewed with the Bio Clean® and the Contractor immediately upon determination of the error.
After completion of installation, a checklist should be reviewed to ensure proper installation of
the Inlet Filter system. The checklist should include key criteria for determination of proper
installation. This checklist should be reviewed in its entirety at the completion of the installation
and kept as documentation of proper installation. If during the checklist review an error is
determined, the documented error should be reported to Bio Clean® as well as the Owner and
Engineer. The checklist includes key criteria such as:
29
• The catch basin is clean and free of trash and debris.
• The grate is properly seated in the frame and does not protrude above the frame.
• The grate is properly oriented to receive storm drain flow (ensure the veins of the grate
are positioned in the direction of water flow).
• The filter basket has been properly sealed.
• Inlet/Outlet pipes to/from the catch basin are not blocked or impeded as a result of the
filter installation.
• Inlet Filter and Inlet Filter components are not bent, broken, or damaged.
• All debris from installation has been cleaned and removed.
• All components are free of sharp corners and edges.
• Optional hydrocarbon absorbent booms are installed and free to float within the filter
basket.
Additionally the Grate Inlet and Curb Inlet Filters can be inspected after commencement of
operation to determine proper operation.
5.0 OPERATION AND MAINTENANCE INFORMATION
5.A. Inspection procedures and frequency considerations;
The Grate Inlet Filter Operation and Maintenance Manual and Curb Inlet Filter Operation and
Maintenance Manual are included with this submittal as Appendix D. These manuals include
detailed requirements and recommendations for operation and maintenance of the Inlet Filters
when used as Full Capture Trash Treatment Control Devices. A summary of requirements and
recommendations are listed below:
Maintenance Summary
• Clean filter basket. Typical service interval occurs once every 12 months (≈ 10 minute
service time).
• Replace optional hydrocarbon media booms. Typical replacement occurs once every 12
months (≈ 5 minute service time).
Notes:
• Maintenance cycles are dependent on site-specific pollutant loading.
• Maintenance operations should be planned to occur just prior to start of the rainy season
and at the termination of the rainy season for the most effective system operation.
30
Inspection Procedures
• Following the installation of a Grate Inlet Filter or Curb Inlet Filter, the unit will require
periodic and scheduled maintenance. Bio Clean® or a Bio Clean® approved contractor
can provide inspection and maintenance services.
• Inspection of the Inlet Filters should be quick and require no entry into the catch basins or
extensive use of equipment. The inspection should provide a general assessment of the
condition and operation of the Inlet Filter and an estimate as to the need or timing for
maintenance.
o The primary observation during inspection is the condition of the filter basket.
The filter basket should be in good, working condition and should be free from
obstructions or blockages. Accumulated trash levels should be documented and if
maximum capacity levels are exceeded, maintenance should occur.
5.B. Description of maintenance frequency considerations related to the
Device’s hydraulic capacity at various levels of trash capture volumes;
Standardized maintenance frequencies that are suitable for most sites are detailed in Section 5.A.
Maintenance frequency is very site specific depending on pollutant loading. Records from
inspections and prior maintenances should be periodically reviewed to assess the appropriateness
of the prescribed maintenance frequency. Table 3 and Table 4 in Section 3.c. list the hydraulic
capacities at various levels of trash capture volumes for the Grate Inlet and Curb Inlet Filters
respectively.
5.C. Maintenance procedures, including procedures to clean the trash
capture screen;
A full description of the maintenance procedures is located in the Grate Inlet Operation and
Maintenance Manual and Curb Inlet Operation and Maintenance Manual included with this
submittal as Appendix D. A summary of the key components of the procedures is listed below:
Maintenance Procedures
It is recommended that maintenance occur at least two days after the most recent rain event to
allow debris and sediments to dry out. Maintaining the Device while flows are still entering it
will increase the time and complexity required for maintenance. Cleaning of the Grate Inlet and
Curb Inlet Filter can be performed from finished surface without entry into catch basin utilizing a
vacuum truck. Some unique and custom configurations may create conditions that would require
entry for some or all of the maintenance procedures. Once all safety measures have been set up,
cleaning of the Grate Inlet and Curb Inlet Filter can proceed as follows:
• Remove all manhole cover or access hatches (traffic control and safety measures to be
completed prior).
31
• Using an extension on a vacuum truck, position the hose over the opened manhole, hatch
or grate opening. Insert the vacuum hose down into the filter basket and suck out trash,
foliage, and sediment. A pressure washer is recommended and will assist in spraying of
any debris stuck on the side or bottom of the filter basket. For the Curb Inlet filter, if the
filter basket is overly full, trash, sediment, and debris can accumulate inside the trough
and weir sections of the system. Once the filter basket is clean, power wash the weir and
trough pushing the debris into the filter basket (leave the vacuum hose in the filter basket
during this process so entering debris will be sucked out). Power wash off the trough,
weir, debris screen, and filter basket sides and bottom.
• Next, remove the optional hydrocarbon boom (if installed) that is attached to the inside of
the filter basket. They hydrocarbon boom is fastened to rails on two opposite sides of the
basket (vertical rails). Assess the color and condition of the boom using the color chart
guide. If replacement is required, install and fasten in place a new hydrocarbon boom.
Booms can be ordered directly from the manufacturer.
• The last step is to close up and replace the manhole or hatch and remove all traffic
control.
• All removed debris and pollutants shall be disposed of following local and state
requirements.
• Disposal requirements for recovered pollutants may vary depending on local guidelines.
In most areas, the sediment, once dewatered, can be disposed of in a sanitary landfill. It is
not anticipated that the sediment would be classified as hazardous waste.
• In the case of damaged components, replacement parts can be ordered from the
manufacturer.
Record Keeping Maintenance Procedures
• Following maintenance and/or inspection, the maintenance operator shall prepare a
maintenance/inspection record. The record shall include any maintenance activities
performed, amount and description of debris collected, and condition of the system and
its various filter mechanisms.
• The owner shall retain the maintenance/inspection record for a minimum of five years
from the date of maintenance. These records shall be made available to the governing
municipality for inspection upon request at any time.
5.D. Essential equipment and materials for proper maintenance activities;
The following equipment is helpful when conducting Grate Inlet Filter and Curb Inlet Filter
inspections and maintenance:
• Recording device (pen and paper form, voice recorder, iPad, etc.)
• Suitable clothing (appropriate footwear, gloves, hardhat, safety glasses, etc.)
• Traffic control equipment (cones, barricades, signage, flagging, etc.)
• Manhole hook or pry bar
32
•Flashlight
•Tape measure
•Measuring stick or sludge sampler
•Confined space entry equipment (if necessary)
•Vacuum truck
•Pressure washer
•Replacement absorbent booms
5.E. Description of the effects of deferred maintenance on device structural
integrity, performance, odors, etc.; and
Delayed or deferred maintenance can cause diminished pollutant removal, re-entrainment of
pollutants in catch basin and upstream hydraulic impacts, and impacts to water quality.
5.F. Repair Procedures for the Device’s structural and screening
components.
In the case that damage is done to any part of the Bio Clean® Grate Inlet and Curb Inlet Filter,
there are two approaches to repairing the damaged baskets. For minor damage, Bio Clean® can
send out a field welder to fix the basket on the spot. In cases where the damage is more
extensive, Bio Clean® recommends removing the damaged basket and replacing it with a new
one to ensure that all installed devices adhere to full capture requirements. In most cases
regarding damage, Bio Clean® recommends replacing the entire basket.
6.0 VECTOR CONTROL ACCESSIBILITY
6.A. The date the Device application was submitted for vector control
accessibility design verification via email to the Mosquito Vector Control
Association of California (MVCAC) (Trashtreatment@mvcac.org);
An application was originally submitted to the Mosquito Vector Control Association of
California (MVCAC) via email on January 4, 2021, with approval received on January 27, 2021.
With the addition of the alternative configuration, a new application was submitted to MVCAC
via email on September 29, 2021 and a revised verification letter was received on October 20,
2021. It is attached as Appendix G.
33
6.B. Description and/or video that demonstrates how mosquito vector
control personnel can readily access the bottom of the storm water vault
and/or Device for visual observation and mosquito treatment; and
Bio Clean® designed the Grate Inlet and Curb Inlet Filter with access that facilitates
maintenance. Filter baskets are located directly beneath the grate of the catch basin for the Grate
Inlet version of the Filter. Filter baskets are located directly beneath the manhole access covers
and/or hatches for the Curb Inlet basket of the Filter. Filter baskets are easily removed providing
direct, unimpeded access to the catch basin.
While in operation, the Grate Inlet and Curb Inlet Filters are designed to be free of standing or
constant pools of water in both the Filters and the catch basins. In addition, filter baskets are
suspended above the catch basin bottoms allowing the contents to dry between storm events.
Because of the absence of any standing water and because prolonged wet conditions are not
anticipated, vector are not anticipated as a result of the installation and operation of the Filters.
It should be noted that some catch basins may be inadequately constructed and may be prone to
retaining water even small amounts, which can be problematic for mosquito breeding. The
preferred course of action is to repair any deficiencies that may cause standing water in a catch
basin prior to installation of a Full Capture Device, it is critical that the deficient areas be visible
and accessible by Vector/Mosquito Control personnel.
To accommodate visibility and accessibility by Vector/Mosquito Control personnel, the Bio
Clean® Grate Inlet Filter features a viewing/access port built into the top flange of the basket.
This viewing port is located at the corner of the top flange and varies in size; as the flange and
basket get larger, the viewing port gets larger. The viewing port is made as large as possible to
give maximum visibility to Vector/Mosquito Control personnel. This viewing port has an access
cover attached via a pivot point with a tab at the end so that the viewing port can easily be
rotated opened without removing the grate. Figure 22 illustrates the viewing port in a catch
basin, and Figure 23 is a sample drawing of this viewing port. The example drawing in Figure
23 is based on a 20-inch x 20-inch top flange. The 5-inch diameter viewing port will be the
minimum size, and as the top flange grows, the access hole will grow with it. This applies to
both standard and additional configuration baskets.
The Bio Clean® Curb Inlet Filter is located directly beneath the manhole opening for easier
cleaning. The location of the filter does not impede Vector/Mosquito control activities however.
The filter is located at an elevation that allows an acute angle view and access on the sides of the
filter. Figure 24, Figure 25, and Figure 26 illustrates this view for an installed filter in a typical
catch basin. Visibility and access beneath the filter is facilitated by a design feature on the filter.
In the case of larger catch basins, extra precautions are put into place during the filter installation
to ensure visibility and accessibility by Vector/Mosquito Control personnel. In these instances,
the Back Weir Section of the filter will be no larger than 8-inches tall, and the filter will be
installed 12-inches lower than normal. The limits placed on the back weir and the additional 12-
inch of clearance create adequate visibility and accessibility in even the largest of vaults, as
illustrated in Figure 27 and Figure 28.
34
Figure 22 • Top View Rendering of viewing port in Bio Cleon• orate Inlet Filter
(
.,
• (t '<>!U ~{<Ylf()I""
A,;;,;;~1'101.ttlll',ll:JU04
~S" A80VE l!OSB)ASA
RffEl!fl'JCE. ,'S TOf> FlANOE cm
LAllG£R. rHE~Ef?OflHE ACCESS HOU ~SA$ ''-Ell TOMAXtMll'E •IAJJtl \1191!1tff'Y.• :::.."-"="-"··"·"-"" .. E!::'" -
Figure 23 • sample drawings of Bio dean• orate Inlet Filter viewing port
35
•
• •
Figure 24 • View 1 of Catch Bosin Bottom wirh Bio Cleon• curb mlerFiltermsta/led
Figure 25 • View 2 of catch Bo sin Bottom with Bio Cleon• curb m/er Filter msta/Jed
36
r,sun 26 • \Ii-, 3 of Catch Basin Bottom with Bio Ckon• Cun, tn~t Fil~rlnsto.l.~d
12• O@arance
37
6.C. The MVCAC Letter of Verification as an attachment to the application
when it becomes available. This letter shall verify that the Device design
allows full visual access for presence of standing water and treatment of
mosquitos when necessary. Table of Contents shall note the MVCAC approval
letter.
An updated Letter of Verification from the MVCAC was received on October 20, 2021 and is
attached as Appendix G.
7.0 RELIABILITY INFORMATION
7.A. Estimated design life of Device components before major overhaul;
The estimated design life for the Grate Inlet and Curb Inlet systems is 25 to 50 years. The design
life is dependent on the materials utilized as well as the proper application of those materials.
7.B. Warranty Information; and
Bio Clean® provides an eight year limited warranty for the Grate Inlet and Curb Inlet Filter per
the conditions listed in the warranty document included in the submittal in Appendix E.
7.C. Customer support Information
Bio Clean® is a California based company and has three facilities to provide Customer Support
within the State.
Bio Clean® Corporate Office
398 Via El Centro
Oceanside, CA 92058
Phone: (760) 433-7640
Office Fax: (760) 433-3176
info@Bio_CleanEnvironmental.com
Maintenance@Bio_CleanEnvironmental.com
38
8.0 FIELD/LAB TESTING INFORMATION AND ANALYSIS
8.A. For devices with 5mm screening, any available field/lab testing
information that demonstrates the device functionality and performance; and
Bio Clean® conducted laboratory testing on the proprietary non-blocking screen material utilized
in the Grate Inlet and Curb Inlet Filters. Bio Clean® conducted this testing to empirically
determine the unique properties of the screen including the Effective Open Area (EOA), the
Coefficient of Discharge (Cd), and the flow capacity and characteristics. The results of the testing
provided a clear relationship between discharge (Q) and head (h) acting on the screen. The
results of the testing have been incorporated into the design of the Filters to determine both the
treatment and peak flow rates for the Filters.
The test report has been included in this Application in Appendix F for review by the SWRCB
and interested parties.
8.B. If the Device does not include a 5mm screen, adequate field/lab testing
information that demonstrates the Device captures trash particles of 5mm or
greater.
The Grate Inlet and Curb Inlet Filters include a 5mm screen with lab testing, which is available
in Appendix F.
44
APPENDIX B
Stormwater Catch Basin Filtration Device Page 1 of 5
Section [________]
Stormwater Catch Basin Filtration Device
PART 1 – GENERAL
01.01.00 Purpose
The purpose of this specification is to establish generally acceptable criteria for devices used for
filtration of stormwater runoff captured by catch basins with grates. It is intended to serve as a guide
to producers, distributors, architects, engineers, contractors, plumbers, installers, inspectors, agencies
and users; to promote understanding regarding materials, manufacture and installation; and to provide
for identification of devices complying with this specification.
01.02.00 Description
Stormwater Catch Basin Filtration Devices (SCBFD) are used to filter stormwater runoff captured by
catch basins. The SCBFD is a filter system composed of a SCBFD with a media filtration storm boom.
SCBFDs are used to remove various pollutants from stormwater by means of screening, separation
and media filtration.
01.03.00 Manufacturer
The manufacturer of the SCBFD shall be one that is regularly engaged in the engineering, design and
production of systems developed for the treatment of stormwater runoff for at least (10) years, and
which have a history of successful production, acceptable to the engineer of work. In accordance with
the drawings, the SCBFD(s) shall be a filter device manufactured/distributed by Bio Clean
Environmental Services, Inc., or assigned distributors or licensees. Bio Clean Environmental
Services, Inc. can be reached at:
Corporate Headquarters:
398 Via El Centro
Oceanside, CA 92058
Phone: (760) 433-7640
Fax: (760) 433-3176
www.biocleanenvironmental.net
01.04.00 Submittals
01.04.01 Submittal drawings will be provided with each order to the contractor and
engineer of work.
01.04.02 Submittal drawings are to detail the SCBFD, its components and the
sequence for installation, including:
SCBFD configuration with primary dimensions
Various SCBFD components
Any accessory equipment
01.04.03 Inspection and maintenance documentation submitted upon request.
01.05.00 Work Included
01.05.01 Specification requirements for installation of SCBFD.
01.05.02 Manufacturer to supply SCBFD(s):
Filter Basket
Media Filtration Storm Boom
Bio ~Clean
A Forterra Company
Stormwater Catch Basin Filtration Device Page 2 of 5
01.05.03 Media Filtration Boom shall be provided with each Filter Basket housed in
nylon netting and securely fastened entrance to the Filtration basket. Each
media boom shall contain polymer beads to permanently absorb
hydrocarbons.
01.06.00 Reference Standards
ASTM A 240 Standard Specification for Chromium and Chromium-Nickel Stainless Steel Plate,
Sheet, and Strip for Pressure Vessels and for General Applications
ASTM F 716 Testing Sorbent Performance of Absorbents
ASTM F 726 Sorbent Performance of Absorbents
ASTM D3787 - 07 Standard Test Method for Bursting Strength of Textiles-Constant-Rate-of-Traverse
(CRT) Ball Burst Test
ASTM D2690-98 Standard Test Method for Isophthalic Acid in Alkyd and Polyester Resins
ASTM C 582-02 Standard Specification for Contact-Molded Reinforced Thermosetting Plastic
(RTP) Laminates for Corrosion-Resistant Equipment
ASTM D 638 Standard Test Method for Tensile Properties of Plastics
ASTM D 790 Standard Test Methods for Flexural Properties of Unreinforced and Reinforced
Plastics and Electrical Insulating Materials
ASTM D 648 Standard Test Method for Deflection Temperature of Plastics Under Flexural Load
in the Edgewise Position
ASTM D 2583 Standard Test Method for Indentation Hardness of Rigid Plastics by Means of a
Barcol Impressor
ASTM D 4097 Standard Specification for Contact-Molded Glass-Fiber-Reinforced Thermoset
Resin Corrosion-Resistant Tanks
ASTM D3409 Standard Test Method for Adhesion of Asphalt-Roof Cement to Damp, Wet, or
Underwater Surfaces
IFI 114 Break Mandrel Blind Rivets
PART 2 – COMPONENTS
02.01.00 Filter Basket Components
All SCBFD components must be made of stainless steel, per these specifications. SCBFD's
containing any fabrics or plastics will not be accepted.
02.01.01 Filter Housing shall be manufactured of 100% stainless steel.
02.02.02 Side Screens shall be manufactured of 100% stainless steel louver expanded
metal with openings equal to or less than 4.7 mm in size.
Screens shall be oriented with openings opposite to the flow of
water into the filter and be non-clogging based on perpetual
deflective shielding.
02.02.03 Bottom Screens shall be manufactured of 100% stainless steel perforated
round openings less than 5 mm in size.
02.02.04 Media Filtration Boom shall be made up of granulated oil absorbing polymers
that have been tested in accordance with section 11.2 of ASTM F 716.07 and
held within a netting.
Oil absorbing polymers must be proven to absorb 180% of its
weight within a 300 second contact time, and at this absorption
percentage the physical increase in the size of the granules is not
more that 50%.
Bio ~Clean
A Forterra Company
Stormwater Catch Basin Filtration Device Page 3 of 5
Netting shall be 100% polyester with a number 16 sieve size, and
strength tested per ASTM D 3787.
Filter netting shall be 100% polyester with a number 16 sieve
size, and strength tested per ASTM D 3787.
PART 3 – PERFORMANCE
03.01.00 General
03.01.01 Function - The SCBFD has no moving internal components and functions
based on gravity flow, unless otherwise specified. Runoff enters the SCBFD
from a catch basin with a grate opening and flows downward into the SCBFD.
This SCBFD shall be positioned directly under the catch basin grate. After
removal of the grate the SCBFD must be able to be removed through the
catch basin opening without any further disassembly Stormwater enters the
inside of the Filter Basket and flows downward toward the bottom portion of
the Basket. The non-clogging screen has openings that are facing upward. As
water flows downward the screening continuously removes debris from the
screen’s surface. Flowing water also makes contact with the Media Filtration
Boom which absorbs free floating oils. Stormwater flow up to the peak
treatment flow rate is processed through the filtration screens. During the
heaviest flows the Basket fills with water and spills out the internal bypass and
into the bottom of the catch basin.
03.01.02 Pollutants - The SCBFD will remove and retain debris, sediments, metals,
nutrients, oxygen demanding substances and hydrocarbons entering the
catch basin during frequent storm events and specified flow rates. For
pollutant removal performance see section 03.02.00.
03.01.03 Treatment Flow Rate - The SCBFD operates using gravity flow. The SCBFD
treatment flow rate varies by size and is provided on the drawings for each
model. Flow rates must be supported by independent lab results.
03.01.04 Bypass Flow Rate – The SCBFD is designed to fit within the catch basin in a
way not to affect the existing hydraulics and treat or bypass all flows. The
bypass must be sized with a surface area greater then the outlet pipe size,
thus the SCBFD shall not be a critical point of flow restriction. Bypass flow
rate must be based on the SCBFD's inlet throat or bypass orifice capacity,
which ever is less.
03.01.05 Pollutant Load – The SCBFD must be designed to have minimum storage
03.01.06 capacity as documented on the drawing for each particular size and model.
03.01.07 Performance Protocol and Results – All lab testing on filtration media must be
performed by an independent third party consultant and testing lab.
03.02.00 Test Performance
At a minimum, the SCBFD shall be tested, according to section 03.01.06, and meet these
performance specifications:
03.02.01 Filter Pollutant Removal Table
POLLUTANT
REMOVAL
EFFICIENCY
Trash and Debris - (down to 5 mm) 100%
Bio ~Clean
A Forterra Company
Stormwater Catch Basin Filtration Device Page 4 of 5
PART 4 - EXECUTION
04.01.00 General
The installation and use of the SCBFD shall conform to all applicable national, state, municipal and
local specifications.
04.02.00 Installation
The contractor shall furnish all labor, equipment, materials and incidentals required to install the
(SCBFD) device(s) and appurtenances in accordance with the drawings, installation manual, and
these specifications, and be inspected and approved by the local governing agency. Installation
contractor should possess a Confined Space Entry Certification Permit, pursuant to OSHA standards.
Any damage to catch basin and surrounding infrastructure caused by the installation of the SCBFD is
the responsibility of the installation contractor.
04.02.01 Filter Basket and all components or accessories shall be inserted through
the catch basin and properly secured per manufactures installation manual
and these specifications.
04.03.00 Shipping, Storage and Handling
04.03.01 Shipping – SCBFD shall be shipped to the contractor’s address and is the
responsibility of the contractor to transport the unit(s) to the exact site of
installation.
04.03.02 Storage and Handling– The contractor shall exercise care in the storage and
handling of the SCBFD(s) and its components prior to and during installation.
Any repair or replacement costs associated with events occurring after
delivery is accepted, and unloading has commenced shall be born by the
contractor. The SCBFD(s) and its components shall always be stored indoors
and transported inside the original shipping container(s) until the SCBFD(s)
are ready to be installed. The SCBFD shall always be handled with care and
lifted according to OSHA and NIOSA lifting recommendations and/or
contractor’s workplace safety professional recommendations.
04.04.00 Maintenance and Inspection
04.04.01 Inspection – After installation, the contractor shall demonstrate that the
SCBFD has been properly installed at the correct location(s), elevations, and
with appropriate supports and fasteners. All components associated with the
SCBFD and its installation shall be subject to inspection by the engineer of
work, governing agency, and the manufacture at the place of installation. In
addition, the contractor shall demonstrate that the SCBFD has been installed
per the manufacturer’s specifications and recommendations. SCBFD(s) shall
be physically inspected regularly in accordance to owner’s Stormwater
Pollution Prevention Plans (SWPPP) and manufacture’s recommendations.
An inspection record shall be kept by the inspection operator. The record
shall include the condition of the SCBFD and its appurtenances. The most
current copy of the inspection record shall always be copied and placed in the
owner’s SWPPP.
04.04.02 Maintenance – The manufacturer recommends cleaning and debris removal
and replacement of the Media Filtration Boom as needed. The maintenance
shall be preformed by someone qualified. A Maintenance Manual is available
upon request from the manufacturer. The manual has detailed information
Bio ~Clean
A Forterra Company
Stormwater Catch Basin Filtration Device Page 5 of 5
regarding the maintenance of the SCBFD(s). A detailed Maintenance Record
shall be kept by the maintenance operator. The Maintenance Record shall
include any maintenance activities preformed, amount and description of
debris collected, and the condition of the filter. The most current copy of the
Maintenance Record shall always be copied and placed in the owner’s
Stormwater Pollution Prevention Plan (SWPPP) per governing agency.
04.04.03 Material Disposal - All debris, trash, organics, and sediments captured and
removed from the SCBFD shall be transported and disposed of at an
approved facility for disposal in accordance with local and state regulations.
Please refer to state and local regulations for the proper disposal of toxic and
non-toxic material.
PART 5 – QUALITY ASSURANCE
05.01.00 Warranty
The manufacturer shall guarantee the SCBFD against all manufacturing defects in materials and
workmanship for a period of (5) years from the date of delivery to the contractor. The manufacturer
shall be notified of repair or replacement issues in writing within the warranty period. The SCBFD is
limited to recommended application for which it was designed.
[End of This Section]
Bio ~Clean
A Forterra Company
Stormwater Catch Basin Filtration Device Page 1 of 6
Section [________]
Stormwater Catch Basin Filtration Device
PART 1 – GENERAL
01.01.00 Purpose
The purpose of this specification is to establish generally acceptable criteria for devices used for
filtration of stormwater runoff captured by catch basins with curb openings. It is intended to serve as a
guide to producers, distributors, architects, engineers, contractors, plumbers, installers, inspectors,
agencies and users; to promote understanding regarding materials, manufacture and installation; and
to provide for identification of devices complying with this specification.
01.02.00 Description
Stormwater Catch Basin Filtration Devices (SCBFD) are used to filter stormwater runoff captured by
catch basins. The SCBFD is a filter system composed of a filter basket, media filtration boom and a
trough system. SCBFDs are used to remove various pollutants from stormwater by means of
screening, separation and media filtration.
01.03.00 Manufacturer
The manufacturer of the SCBFD shall be one that is regularly engaged in the engineering, design and
production of systems developed for the treatment of stormwater runoff for at least (10) years, and
which have a history of successful production, acceptable to the engineer of work. In accordance with
the drawings, the SCBFD(s) shall be a filter device manufactured/distributed by Bio Clean
Environmental Services, Inc. or assigned distributors or licensees. Bio Clean Environmental Services,
Inc. can be reached at:
Corporate Headquarters:
398 Via El Centro
Oceanside, CA 92058
Phone: (855) 566-3938
Fax: (760) 433-3176
www.BioCleanEnvironmental.com
01.04.00 Submittals
01.04.01 Shop drawings are to be submitted with each order to the contractor and
engineer of work.
01.04.02 Shop drawings are to detail the SCBFD, its components and the sequence for
installation, including:
SCBFD configuration with primary dimensions
Various SCBFD components
Any accessory equipment
01.04.03 Inspection and maintenance documentation submitted upon request.
01.05.00 Work Included
01.05.01 Specification requirements for installation of SCBFD.
01.05.02 Manufacturer to supply SCBFD(s):
Filter Basket
Trough System (weir and trough)
Media Filtration Boom
Bio ~Clean
A Forterra Company
Stormwater Catch Basin Filtration Device Page 2 of 6
01.05.03 Media Filtration Boom shall be provided with each Filter Basket housed in
nylon netting and securely fastened entrance to the Filtration basket. Each
media boom shall contain polymer beads to permanently absorb
hydrocarbons.
01.06.00 Reference Standards
ASTM A 240 Standard Specification for Chromium and Chromium-Nickel Stainless Steel Plate,
Sheet, and Strip for Pressure Vessels and for General Applications
ASTM F 716 Testing Sorbent Performance of Absorbents
ASTM F 726 Sorbent Performance of Absorbents
ASTM D3787 - 07 Standard Test Method for Bursting Strength of Textiles-Constant-Rate-of-Traverse
(CRT) Ball Burst Test
ASTM D2690-98 Standard Test Method for Isophthalic Acid in Alkyd and Polyester Resins
ASTM C 582-02 Standard Specification for Contact-Molded Reinforced Thermosetting Plastic
(RTP) Laminates for Corrosion-Resistant Equipment
ASTM D 638 Standard Test Method for Tensile Properties of Plastics
ASTM D 790 Standard Test Methods for Flexural Properties of Unreinforced and Reinforced
Plastics and Electrical Insulating Materials
ASTM D 648 Standard Test Method for Deflection Temperature of Plastics Under Flexural Load
in the Edgewise Position
ASTM D 2583 Standard Test Method for Indentation Hardness of Rigid Plastics by Means of a
Barcol Impressor
ASTM D 4097 Standard Specification for Contact-Molded Glass-Fiber-Reinforced Thermoset
Resin Corrosion-Resistant Tanks
ASTM D3409 Standard Test Method for Adhesion of Asphalt-Roof Cement to Damp, Wet, or
Underwater Surfaces
IFI 114 Break Mandrel Blind Rivets
PART 2 – COMPONENTS
02.01.00 Trough System Components
02.01.01 Trough shall be manufactured from 100% marine grade polyester resin and
fiberglass strands and stainless steel.
The entire fiberglass structure must be coated with a polyester
gel coating with ultra violet inhibitors incorporated into the coating
for maximum ultra violet protection.
Fiberglass must have a minimum thickness of 3/16”.
02.01.02 Weir portion of the Trough System shall be manufactured from 100%
stainless steel.
The Weir shall fully surround the Filter Basket on all sides. On the
end of the weir the sides shall be made of screen with perforated
round openings less than 5 mm in size.
Water flows in access of the capacity of the Filter Basket shall
pass through the additional weir screen for added treatment and
retention of trash and debris during higher bypass flows.
The Weir shall be hinged in the middle along the centerline of the
Filter Basket and hinge upward to allow for access into the catch
basin.
02.01.03 Mounting Hardware shall be 100% non-corrosive metals.
Bio ~Clean
A Forterra Company
Stormwater Catch Basin Filtration Device Page 3 of 6
Nuts and bolts
Rivets
Support brackets
Concrete anchors
02.01.04 Concrete Filler and Sealant shall be made of Acrylic Emulsion and have a
minimum service temperature range of -30°F to 150°F.
02.02.00 Filter Basket Components
02.02.01 Filter Basket Housing shall be manufactured of 100% stainless steel.
02.02.02 Side Screens shall be manufactured of 100% stainless steel louver expanded
metal with openings equal to or less than 4.7 mm in size.
Screens shall be oriented with openings opposite to the flow of
water into the filter and be non-clogging based on perpetual
deflective shielding.
02.02.03 Bottom Screens shall be manufactured of 100% stainless steel perforated
round openings less than 5 mm in size.
02.02.03 Handle shall be manufactured entirely of 100% stainless steel and be
mounted to the Filter Basket Housing using mounting hardware per section
02.01.03
02.02.04 Media Filtration Boom shall be made up of granulated oil absorbing polymers
that have been tested in accordance with section 11.2 of ASTM F 716.07 and
held within a netting.
Oil absorbing polymers must be proven to absorb 180% of its
weight within a 300 second contact time, and at this absorption
percentage the physical increase in the size of the granules is not
more that 50%.
Netting shall be 100% polyester with a number 16 sieve size, and
strength tested per ASTM D 3787.
PART 3 – PERFORMANCE
03.01.00 General
03.01.01 Function - The SCBFD has no moving internal components and functions
based on gravity flow, unless otherwise specified. The SCBFD is composed
of a Trough System, Media Filtration Boom and a Filter Basket. Runoff enters
the SCBFD from a curb opening and flows into the Trough System which is
mounted under the face of the curb opening. It then flows horizontally inside
the System’s Trough to the Weir which holds the Filter Basket. This Trough
System positions the Filter Basket directly under the catch basin access point
(manhole cover, grate or hatch). The Filter Basket can be removed through
the access point without disassembly. The Filter Basket can also be cleaned
without entering the access point by using a vacuum truck. Within the Filter
Basket is a Media Filtration Boom. Water flows through the Weir and into the
Filter Basket. Stormwater enters the inside of the Filter Basket and flows
downward toward the bottom portion of the Basket. The non-clogging screen
has openings that are facing upward. As water flows downward the screening
continuously removes debris from the screen’s surface. Flowing water also
makes contact with the Media Filtration Boom which absorbs free floating oils.
Stormwater flow up to the peak treatment flow rate is processed through the
Bio ~Clean
A Forterra Company
Stormwater Catch Basin Filtration Device Page 4 of 6
filtration screens. During the heaviest flows the Filter Basket fills with water
and spills over the top to bypass directly into the bottom of the catch basin,
while previously captured debris and solids are contained by the weir screens
which prevents re-suspension.
03.01.02 Pollutants - The SCBFD will remove and retain debris, sediments, metals,
nutrients, oxygen demanding substances, bacteria and hydrocarbons entering
the filter during frequent storm events and specified flow rates. For pollutant
removal performance see section 03.02.00.
03.01.03 Treatment Flow Rate - The SCBFD operates using gravity flow. The SCBFD
treatment flow rate varies by size and is provided on the drawings for each
model. Flow rates must be supported by independent lab results.
03.01.04 Bypass Flow Rate – The SCBFD is designed to fit within the catch basin in a
way not to affect the hydraulics. The area over the top of the Trough System
is always greater than the curb opening area and/or the area of the outflow
pipe. Therefore, the SCBFD does not create a critical point of restriction.
03.01.05 Pollutant Load – The SCBFD must be designed to have minimum storage
capacity as documented on the drawing for each particular size and model.
03.01.06 Performance Protocol and Results – All lab testing on filtration media must be
performed by an independent third party consultant and testing lab.
03.02.00 Test Performance
At a minimum, the SCBFD shall be tested, according to section 03.01.03 & 03.01.06, and meet these
performance specifications:
03.02.01 Filter Pollutant Removal Table
03.02.02 Maintenance Performance – The Filter Basket must be able to be maintained
and cleaned from finish surface using a vacuum hose inserted through the
manhole or hatch opening and not the curb face. All cleaning shall be done
without entering the catch basin. The Filter Basket shall be removable from
finish surface and reinstalled from finish surface without entrance into the
catch basin.
PART 4 - EXECUTION
04.01.00 General
The installation and use of the SCBFD shall conform to all applicable national, state, municipal and
local specifications.
04.02.00 Installation
The contractor shall furnish all labor, equipment, materials and incidentals required to install the
(SCBFD) device(s) and appurtenances in accordance with the drawings, installation manual, and
these specifications, and be inspected and approved by the local governing agency. Installation
contractor should possess a Confined Space Entry Certification Permit, pursuant to OSHA standards.
Any damage to catch basin and surrounding infrastructure caused by the installation of the SCBFD is
the responsibility of the installation contractor.
POLLUTANT
REMOVAL
EFFICIENCY
Trash and Debris - (down to 5 mm) 100%
Bio ~Clean
A Forterra Company
Stormwater Catch Basin Filtration Device Page 5 of 6
04.02.01 Trough System will be installed in accordance with manufactures’
recommendations. The Trough component will be installed the complete width
of the curb opening, or underneath any wings as to provide 100% coverage of
incoming stormwater. The Weir component of the Trough System must be
located directly under the manhole opening or other access point (not
including the curb opening) regardless of its position relative of the curb
opening. The Trough System must be properly mounted and assembled
inside the catch basin with drive pins and pop rivets per manufacture’s
recommendations. Once the Trough System is secured to the walls of the
catch basin all seams must be filled with sealant per section 02.01.03.
04.02.02 Filter Basket will be inserted through the manhole opening or access point
of the catch basin directly without entry into the basin. The Filter Basket shall
be fully visible from finish surface while looking into the access point for ease
of inspection and maintenance. The curb opening itself is not a point of
access as maintenance personnel cannot enter.
04.03.00 Shipping, Storage and Handling
04.03.01 Shipping – SCBFD shall be shipped to the contractor’s address and is the
responsibility of the contractor to transport the unit(s) to the exact site of
installation.
04.03.02 Storage and Handling– The contractor shall exercise care in the storage and
handling of the SCBFD(s) and its components prior to and during installation.
Any repair or replacement costs associated with events occurring after
delivery is accepted, and unloading has commenced shall be born by the
contractor. The SCBFD(s) and its components shall always be stored indoors
and transported inside the original shipping container(s) until the SCBFD(s)
are ready to be installed. The SCBFD shall always be handled with care and
lifted according to OSHA and NIOSA lifting recommendations and/or
contractor’s workplace safety professional recommendations.
04.04.00 Maintenance and Inspection
04.04.01 Inspection – After installation, the contractor shall demonstrate that the
SCBFD has been properly installed at the correct location(s), elevations, and
with appropriate supports and fasteners. All components associated with the
SCBFD and its installation shall be subject to inspection by the engineer of
work, governing agency, and the manufacture at the place of installation. In
addition, the contractor shall demonstrate that the SCBFD has been installed
per the manufacturer’s specifications and recommendations. SCBFD(s) shall
be physically inspected regularly in accordance to owner’s Stormwater
Pollution Prevention Plans (SWPPP) and manufacture’s recommendations.
An inspection record shall be kept by the inspection operator. The record
shall include the condition of the SCBFD and its appurtenances. The most
current copy of the inspection record shall always be copied and placed in the
owner’s SWPPP.
04.04.02 Maintenance – SCBFD(s) must be completely maintained from outside the
catch basin. The SCBFD(s) shall be inspected, maintained and cleaned 1 to
4 times a year and/or in accordance to owner’s Stormwater Pollution
Prevention Plans (SWPPP). The maintenance shall be preformed by
someone qualified. A Maintenance Manual is available upon request from the
manufacturer. The manual has detailed information regarding the
maintenance of the SCBFD. A Maintenance Record shall be kept by the
Bio ~Clean
A Forterra Company
Stormwater Catch Basin Filtration Device Page 6 of 6
maintenance operator. The Maintenance Record shall include any
maintenance activities preformed, amount and description of debris collected,
and the condition of the filter. The most current copy of the Maintenance
Record shall always be copied and placed in the owner’s SWPPP.
04.04.03 Material Disposal - All debris, trash, organics, and sediments captured and
removed from the SCBFD shall be transported and disposed of at an
approved facility for disposal in accordance with local and state regulations.
Please refer to state and local regulations for the proper disposal of toxic and
non-toxic material.
PART 5 – QUALITY ASSURANCE
05.01.00 Warranty
The manufacturer shall guarantee the SCBFD against all manufacturing defects in materials and
workmanship for a period of (8) years from the date of delivery to the contractor. The manufacturer
shall be notified of repair or replacement issues in writing within the warranty period. The SCBFD is
limited to recommended application for which it was designed.
[End of This Section]
Bio ~Clean
A Forterra Company
ATTACHMENT 2
BACKUP FOR PDP HYDROMODIFICATION CONTROL MEASURES
[This is the cover sheet for Attachment 2.]
Indicate which Items are Included behind this cover sheet:
Attachment
Sequence
Contents Checklist
Attachment 2a Hydromodification Management
Exhibit (Required)
Included
See Hydromodification Management
Exhibit Checklist on the back of this
Attachment cover sheet.
Attachment 2b Management of Critical Coarse
Sediment Yield Areas (WMAA Exhibit
is required, additional analyses are
optional)
See Section 6.2 of the BMP Design
Manual.
Exhibit showing project drainage
boundaries marked on WMAA
Critical Coarse Sediment Yield
Area Map (Required)
Optional analyses for Critical Coarse
Sediment Yield Area Determination
Appendix H.6.1 Verification of
Geomorphic Landscape Units
Onsite
Appendix H.7 Downstream
Systems Sensitivity to Coarse
Sediment
Attachment 2c Geomorphic Assessment of Receiving
Channels (Optional)
See Section 6.3.4 of the BMP Design
Manual.
Not performed
Included
Attachment 2d Flow Control Facility Design and
Structural BMP Drawdown
Calculations (Required)
See Chapter 6 and Appendix G of the
BMP Design Manual
Included
~
V
...
V
...
V
~
V
Use this checklist to ensure the required information has been included on the
Hydromodification Management Exhibit:
The Hydromodification Management Exhibit must identify:
Underlying hydrologic soil group
Approximate depth to groundwater
Existing natural hydrologic features ( watercourses, seeps, springs, wetlands)
Critical coarse sediment yield areas to be protected (if present)
Existing topography
Existing and proposed site drainage network and connections to drainage offsite
Proposed grading
Proposed impervious features
Proposed design features and surface treatments used to minimize imperviousness
Point(s) of Compliance (POC) for Hydromodification Management
Existing and proposed drainage boundary and drainage area to each POC (when necessary,
create separate exhibits for pre-development and post-project conditions)
Structural BMPs for hydromodification management (identify location, type of BMP, and
size/detail)
/\
~ ~ ~ ~ ~ /\
ATTACHMENT 2a
FH
FH
FH
V
FH
V
V
V
V
◊
◊
DMA 3
DMA 4
DMA 1
DMA 2
DMA 5
DMA 7
HI
D
D
E
N
V
A
L
L
E
Y
R
O
A
D
DMA 6
BMP C
BMP D
BMP E
BMP B
BMP F
PALOMAR AIRPORT ROAD
HYDROMODIFICATION EXHIBIT FOR
NORTH COAST MEDICAL PLAZA PHASE I & II
**AIAIN!ENANCE AREA NO!E
SEE I.IA/NTENANCE EXHIBIT SHOW/NC
TH£ 01€RALL SITE II.IPERllfOI/S
PERCENTAGE REDt/CllON.
~Slfl1J (1
NO. t5'/jsT0Nff
;r-\( '\\ I
~•pi,c
CSI/BORAIN C
~-mt BASIN
PER PLAN
SCH 40 pvr:; NALE
ADAPTER (Ni1PxSoC)
SCH 40 pvr:; TllREA/JElJ
£NO CAP (fPT)
rii'i'===c.==ii's==F===!J----WJ1'--0R/LL OR/RCE HOLE AT ~ /I MIN. iLJ C]~ t flO/ff.lNE OF £NO CAP
J;-• (SIZE PER BIO-BASIN
\__AASHTO SUI.INARY TABLE)
NO. 57 STONE
ORlflCE OETAIL
NOT TO SCALE
6" PVC PIPE PERFORAllON
LA Yot/T OETAIL
NOT TO SCALE
ONA /0 ONA AREA
(SQFT)
ONA-/ 5,09J
OI.IA-2 6,645
OI.IA-J J4,J69
OI.IA-4 24,824
OI.IA-5 8,702
OI.IA-6 9,481
OI.IA-7 JJJ
TOTAL 89,446
-
I
I
I I
I
~
IZ I
I
I
I
I -
/I.IPERllfOI/S PERllfOI/S
AREA AREA ONA ORA/NS TO TYPE OF Bl.IP
(SQFT) (SOFT)
4,/68 925 ORA/NS TO Bl.IP-A B/ORL !RA 110N
4,844 1,801 ORA/NS TO BI.IP-B B/ORL !RA 110N
J0,507 3,862 ORA/NS TO BI.IP-C B/ORL !RA 110N
20,764 4,060 ORA/NS TO BI.IP-0 B/ORL !RA 110N
6,6JJ 2,069 ORA/NS TO Bl.IP-£ B/ORL !RA 110N
7,149 2,JJ/ ORA/NS TO BI.IP-F B/ORL !RA 110N
JJJ 0 0£ I.IIN/1.1/S N/A
74,J98 15,048
HYDROLOGICAL SOIL CRotJP
TH£ HYROf.OC/CAL SO'L CROUP FOR
THIS SITE IS TYPE (C)
NO!E·
APPRO)(fl.lA TE 0£Plll TO CROIJNOl'IA !ER
IS 14' (PER CEOTECHNICAL REPORT
OATElJ 9 SEPTBIBER 2022)
ONA S//1.1!.IAR Y TABLE
EFFEC111€ NA)(
HYOR0!.100 Bl.IP AREA 1/NOERORAIN
(SQFT) flOl'IRA TE (CFS)
/4/ O.O/J5
498 O.O/J5
!,JJ6 0.0285
!,4/1 O.OJOJ
508 0.0/18
J89 0.0/18
N/A N/.4
4,285
TOP OF RISER CLEANOI/T Bl.IP Al AJ A2 {INCH) (INCH) {INCH)
9.75 /5 9
9 /9 9
9 /5 9
9 /5 9
/0 /9 9
17 /9 9
N/A N/A N/.4
SCALE !'=40'
LEGEND
•
------------
->-->-->-
----)()(----
- --(XX}-- -
----(XX}-- -
1.1£0/A
C
{INCH)
/8
/8
/8
/8
/8
/8
N/A
D
m
El
CRA!fl
0 £
BOX RISER/
0//ERfl ow
SlRI/C Tl/RE {INCH) (ffET) SIZE (INCHES)
24 J.25 J6)(J6
24 4.25 24)(24
/8 J.25 24)(24
24 J.25 24)(J6
/2 4.25 24)(24
/2 4.25 24)(24
N/.4 N/.4 N/A
------ -0 40 80 120 160
PROPER TY 80//NOAR Y
£AS£1.1£NT LIN£
POINT OF CO/,IPL/ANCE
PROPOSED II.IPERllfOIJS AREA
(AC OR/I€ AISLE)
PROPOSED /I.IPERllfOIJS AREA
(AC PARKING)
PROPOSED IVPERllfOIJS AREA
(CONCRE!E)
PROPOSED IVPERllfOIJS AREA
(BIi/LO/NC)
PROPOSED PERllfOIJS AREA
ONA BOIJNOAR Y
flOl'I 0/RECTlON (SURFACE)
flOl'I OIRECTlON (STORI.I ORAIN)
PROPOSED I.IA.JOR CONTOIJR
PROPOSED Al/NOR CONTOI/R
£)(!S11NC I.IA.JOR CONTOI/R
£)(!S11NC I.I/NOR CONTOIJR
£)(!S11NC STORI.I ORA/N
PROPOSED STORI.I ORAIN
PROPOSED CA ml BASIN
PROPOSED RIP RAP
PROPOSED Cl/RB 1/NOERORAIN
PROPOSED Cl/RB OPENING
LOHEROR/RCE /I.IPERI.IEABLE
OIAI.IETER (INCH) LINER?
0.5 ~s
0.5625 ~s
0. 75 ~s
0. 75 ~s
0.5 ~s
0.5 ~s
N/.4 N/A
EXCEL
ENGINEERING
W/0 PUN/I/NC •ENG/NH/I/NG. !1Jlll£11NG
#II sWt PiAcl; ~ CA 92029
ff/ {760)7~118 fX (760)745-1890
ATTACHMENT 2b
MANAGEMENT OF
CRITICAL COARSE
SEDIMENT YIELD AREAS
Legend
Potential Ciritical Course Sediment
Proposed NCMC Site
600 ft
N
➤➤
N
ATTACHMENT 2d
ATTACHMENT 2d
Table of Contents
INTRODUCTION
Section I Pre- and Post-Development Model Setup ……………………………………………….………………… 3
Section II System Representation ….…………………………………………………………………………………………. 8
Section III Continuous Simulation Options …..…..……………………………………………………….… …………. 13
Section IV Bio-filtration As LID Control ……………….……………………………………………..…………………….. 14
Section V Running the Simulation …..……………………………………………………….………………………………. 17
Section VI Result Analysis ………….…..…………………………………………………………………………………………. 18
Section VII Summary and Conclusion …………………………………………………………………………………………. 27
ATTACHEMENTS
Attachment A SWMM Statistics Analysis, Flow Duration Curve and Pass/Fail Table
Attachment B SWMM Input Data Summary and Detail
INTRODUCTION
This report provides Hydromodification and Water Quality design based on LID (Low Impact Development)
principles for a proposed Medical Office located adjacent to and on the south side of Palomar Airport Road
between Hidden Valley Road and Aviara Parkway, City of Carlsbad, San Diego County, California. This site has a
Planned Industrial (PI) General Plan land use designation and is zoned Planned Industrial Qualified
Development Overlay (P-M-Q).
The Hydromodification and Water Quality calculations were performed utilizing continuous simulation
analysis to size the storm water treatment and control facilities. Storm Water Management Model (SWMM)
version 5.0 distributed by USEPA is the basis of all calculations within this report. SWMM generates peak flow
recurrence frequencies and flow duration series statistics based on an assigned rain gauge for
predevelopment, unmitigated post-development flows and post-development mitigated flows to determine
compliance with the State Water Resources Control Board Order No.R9-2015-001 and Hydromodification
Management Plan (HMP) requirements.
The proposed tributary area is approximately 2.05 acres and this project is planned for Medical Office facility
serviced by private driveways and parking lots. There is only one point of compliance (POC) in the analysis;
POC receives flows from basin A, B, C, D, and E from the east portion of the site and receives flows from basin
F from the west side.
The Hydromodification and Water Quality system proposed for this project is 6 bio-filtration basins with one
point of compliance located on the west side of the project. This system detains storm water to the basin
surface and in the underdrain reservoir. Bio-filtration filters storm water through plant roots and a biologically
active soil mix, and then releases it into the existing storm drain system which currently collects the sites
storm flows. The resulting mitigated outflows are shown to be equal to or less than all continuously simulated
storms based on the historical data collected from the Oceanside rain gage.
Low Flow Threshold
A downstream channel assessment has not been completed for this project and therefore the low flow
threshold utilized for the system analysis is 10% of 2-year storm event (0.1Q2). This will be used as the low
flow threshold to meet peak flow frequency and flow duration controls.
Soil Investigations
There is a geotechnical investigation from Partner; which performed a geotechnical evaluation. Based on
findings from the geotechnical investigation and from the BMP manual dated October 13, 2016 & Addendum
dated September 9, 2022; the hydrological soil type is “C” (see attached letter). Therefore, the SWMM sub-
catchments were based on infiltration rate of soil type C. The original grading for the site and the
overexcavation areas for the pad the deep over excavation areas that were created will minimize the native’s
soil infiltration rate for the pervious area.
SECTION I. MODEL SETUP
Pre-development Model Setup
The SWMM model for this project’s pre-development site is analyzed using historical rain gauge data. The
Oceanside Rain gauge is utilized for this project. That data provides continuous precipitation input to a sub-
catchment with its outfall based on the contributing basins imperviousness.
The imperviousness parameter in SWMM is the amount of effective or directly connected impervious area.
The effective impervious area is the impervious area that drains directly to the Stormwater conveyance
system. The pre-development condition is a vacant pad with poor cover of some grasses with no trees. No
other impervious surface exists on site of the on-site area has been disturbed (the site is padded and has been
compacted).
Post-Development Model Setup
Figure 2 illustrates each contributing basin discharging its overland flow directly into the biofiltration system.
Each biofiltration layer section has a similar configuration as seen in the detail in Figure 1. There is no actual
elevation entered in the program. The bottom elevation of the biofiltration surface storage is assumed at 0 ft.
Storm drain pipe is also utilized as a detention by having an orifice small flow restrictor at a lower invert
elevation of the downstream cleanout box and a bypass orifice/pipe to convey the bigger flow.
This project layout includes the construction of a new parking lot and medical office building with 6 biofiltration
systems onsite. Once within the water quality treatment systems, the stormwater infiltrates through the
treatment medium into underdrains that route the flows to the private onsite storm drainage system. This
system uses new piping to direct flows to the existing storm drain and ties into the existing storm drainage
system draining northwest towards its outfall location.
The is one small DMA (DMA 7) being treated as de-minimis area as these improvements are removing and
replacing existing impervious areas onsite. These areas have been reduced as much as possible, including the
construction of an additional trench drain to direct as much surface drainage to the biofiltration as possible with
the site constraints.
Figure 1. Typical BMP Detail
l!.IP£Rl1/J(JS
0!.IA 10 0!.IA AREA AREA
(SOFT) (SOFT)
ONA-I 5,09J 1,/68
0!.IA-2 5,615 1,811
OVA-J Jl,J69 .J0,50?
OVA-4 21,824 20,?6-I
OVA-5 8,702 5.oJJ
OVA-6 !UBI 7,149
OVA-7 JJJ JJJ
TOTAL 89,446 71,398
OHA Sl/,/1,//ARY TABLE
P£Rl10//S £/TECH/IE RISER TOP OF ClEANO//T !.IElllA CRA/IEl BOX RISER/
AREA BIJP AREA () Al 8,//P AJ C 0 £ 0/IERR.Olf ONA ORA/NS TO n-PEOFBIJP {CFS) A2 Sll?//Cll/RE (SOFT) (SOFT) {INCH) {INCH) {INCH) (INCH) {INCH) (FEET) SIZE {INCHES)
925 ORA/NS TO BNP-A 81/JRLTRAR& !If ao,JS 9 15 9 18 24 J.25 .J6X.J6
1,801 ORA/NS llJ BNP-B BIOF!LTRAR& 198 ao,JS 19 18 24 4.25 24X24
J,862 ORA/NS llJ BNP-C BIOF!LTRAR& l,J.]6 ao2BS 9 15 9 18 /8 J.25 24X24
,f,/JoO ORA/NS llJ B!.IP-0 BIOF!L !RA nav 1,411 aoJO. 9 15 9 18 2,f J.25 24X.J6
2,/Jo9 ORA/NS TO Bl.IP-£ BIORL TRA nav 508 ao11e fg 18 /2 4.25 24X24
2,JJ! ORA/NS llJ B!.IP-F B/OflLTRAll& .J89 ao11e 19 18 12 4.25 24X24
0 OE !.IINIIJ/S N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A
15,048 1,285
:AMlJtN.(i~ tMSTANCEmtWRX
IV MAllH k I (I' Sl,(',P( R) /.l'O N
IHR£JLTTS QfAlllUJt'R ()#' SIMJtlllN(' NAll'tCJ'Qt £ ANO JI.ANlFNMC£ ACt:t'SS ,(,')l'tW F()II
AH(;/£ ty IJIII.U£Nt£0' l.K/'NCIIRPIY
QliAICl l.Altll AU. LIM/)$
SNflJ. 'tr /: I
ltl'Al(lf atA/lf'Y (NI)$ AT Al
«IT
R1 ,,..,~.,--!t=-t
6. P//C PIPE PEHFORA RON
LAYOUT OE TAIL
N()T !()$CAI.£
l-C.-:\r:cl..-,C<!O( -
AtlS?Slf.lE
... :. -:·. ~·
·-:•:
.• ·':.
J' \_.M$¥10 ,: : ·..t'.
M2 S7 STQIE
ORIRCE OETAIL
l'OiRAH
IIJPl<'M.<i£
A/MP!& /Jllll'>SIJC)
t:Yi'll (MK£ HtX£ ,.,
llO#U'tt tY' /'Jib W
{$1lrl'tNflq.8'$W
SIMIANY TAfUJ
LOIIER OR/RC£ NPER!.IEABLE
/JIANE!ER (INCH) LINER?
as ~s
Y£S
a75 Y£S
a,s Y£S
as Y£S
as Y£S
N/A N/A
Fig. 2 – SWMM Post-Development Model
~·· ••• .. , ... ,..,. ·.·,,•.: '>-' :~ ... ~·,, , .. ,t-,•.: -f
. ~-.
I"'.;;,;-~ ,:: -
OCEANSIDE 121 --
•., .·.• ....
1
I
.I
I
I
I
, .... -:-,,·:;,• ... •:;
,,..._,_ ,· .. _.;-..:. / --~ -~"-
..... •, ........ ·.·; .·,
h•.,.,
,:,: . ... ,;.,~•-
/1 r-;-;,-;
,--~-
j< V •
,, .. ,,, ;,-..;~ .,
·,1 -··• .. '
--------., . . , ,-:.,.. :-i_.,.-,
LE::;EN)
•
___ ,, __ _
I I
I
::JI
i, :,
,.
1J;«44
' ',:_~::.--· .
..... ,,,.,..,.,r..-;,:"''l'" .... ;,, .... -~····. ·• . ., . •, ·•·." ...... ~,
II\ llRO\.!OIJlrlCATION c.Xllll-lll l-01(
,owl l{'()ASrMl•l)I( Al l'I A1/-" l'IIA:-.1 1 1& II
Fig. 3 – SWMM Pre-Development Model
cx:£ANS1oE ~
--
-----·-
------
----,,
-
7 | P a g e
Post-Development Drainage Management Areas (DMAs)
The DMAs provide an important framework for feasibility screening, BMP prioritization and storm water
management system configuration. DMAs are defined based on drainage patterns of the site and the
BMPs to which they drain.
DMAs drain to the biofiltration BMPs A, B, C, D, E, and F before entering the site POC.
Note: Hydromod and Hydrology areas will not equal the same area.
DMA Table
EFFECTIVE AREA TABLE
BMP AREA (SF) AREA (AC.) DMA AREA (AC.)
BMP-A 141 0.003 DMA-1 0.11362
BMP-B 498 0.011 DMA-2 0.1411
BMP-C 1336 0.031 DMA-3 0.7583
BMP-D 1411 0.032 DMA-4 0.5375
BMP-E 508 0.012 DMA-5 0.1881
BMP-F 389 0.009 DMA-6 0.2087
DMA Table for Pre-Development
HYDROMODIFICATION TABLE
SOIL DMA AREA (ACRE) % IMPERV. POC
SOIL C BASIN-1 0.99 0 1
SOIL C BASIN-2 0.83 0 1
SOIL C BASIN-3 0.23 0 1
2.05 TOTAL
HYDROMODIFICATION TABLE
SOIL DMA AREA (ACRE) % IMPERV. POC
SOIL C DMA-1 0.1169 82 1
SOIL C DMA-2 0.1525 73 1
SOIL C DMA-3 0.7890 89 1
SOIL C DMA-4 0.5699 84 1
SOIL C DMA-5 0.1998 75 1
SOIL C DMA-6 0.2176 76 1
SOIL C DMA-7 0.0076 100 1
2.05 TOTAL
8 | P a g e
SECTION II. SYSTEM REPRESENTATION
SWMM is a distributed model, which means that a study area can be subdivided into any number of
irregular sub-catchments to best capture the effect that spatial variability in topography, drainage
pathways, land cover, and soil characteristics have on runoff generation. For modeling of
Hydromodification calculations, there are four main system representations: Rain gage, Sub-catchment
(contributing basin or LID area), Nodes and Links.
Fig. 4 – Time series rain data, which corresponds to runoff estimates for each of the 508,080 time steps (each
date and hour) of the 58-year simulation period. (Inches/hour vs. elapsed time)
Rain Gauge
The properties of a rain gauge describe the source and format of the precipitation data that are applied
to the study area. In this project, the rainfall data consists of a long-term rainfall record stored in a user-
defined Time Series labeled as “Oceanside” rain gauge station. The Oceanside rain station was chosen
due to its data quality and its location to the project site.
The rain gauge supplies precipitation data for one or more sub-catchment areas in a study region taken
from the Project Clean Water website (www.projectcleanwater.org). This data file contains rainfall
intensity, hourly-recorded time interval, and the dates of recorded precipitation each hour. The
Oceanside rain data has approximately 58 years of hourly precipitation data from 8/28/1951 to
5/23/2008 and generates 58 years of hourly runoff estimates, which corresponds to runoff estimates for
each of the 508,080 time steps (each date and hour) of the 58 year simulation period. See Figure 4 for
hourly precipitation intensity graph for 58 years in inches.
Sub-catchment (contributing basin or LID area)
A basin is modeled using a sub-catchment object, which contains some of the following properties:
Ti me Se • es Oceanside
0 100.000 200,00D 300.000 ~00.00D 500.000
Bap,sed Tlme (hours)
9 | P a g e
Rain Gauge
The rate of stormwater runoff and volume depends directly on the precipitation magnitude and its
spatial and temporal distribution over the catchment. Each sub-catchment in SWMM is linked to a
rain gauge object that describes the format and source of the rainfall input for the sub-catchment.
Area
This area is bounded by the sub-catchment boundary. Its value is determined directly from maps or
field surveys of the site or by using SWMM’s Auto-length tool when the sub-catchment is drawn to
scale on SWMM’s study area map. This Project is divided into several sub-catchments based on its
outfall.
Width
Width can be defined as the sub-catchment’s area divided by the length of the longest overland flow
path that water can travel. When there are several such paths, one would use an average of their
lengths to compute a width. If overland flow is visualized as running down –slope off an idealized,
rectangular catchment, then the width of the sub-catchment is the physical width of overland flow.
The method of calculations used following Figure 5 involves an estimation by Guo and Urbonas
(2007). As stated in the Storm Water Management Model Reference Manual Vol. 1
A more fundamental approach to estimating both subcatchment width and sloe has recently been
developed by Guo and Urbonas (2007). The idea is to use “shape factors” to convert a natural
watershed as pictured in Figure 5 into the idealized overland flow plane of Figure 6. A shape factor is
an index that reflects how overland flows are collected in a watershed. The shape factor X for the
actual watershed is defined as A/L2 where A is the watershed area and L is the length of the
watershed’s main drainage channel (not necessarily the length of overland flow). The shape factor Y
for the idealized watershed is W/L. Requiring that the areas of the actual and idealized watersheds
be the same and that the potential energy in terms of the vertical fall along the drainage channel be
preserved, Guo and Urbonas (2007) derive the following expression for the shape factor Y of the
Figure-5 Irregular subcatchment
shape for width calculations
(DiGiano et al., 1977, p.165).
Figure-6 Idealized representation of
a subcatchment.
Source: STORM WATER MANAGEMENT MODEL REFERENCE MANUAL VOLUME 1- JANUARY 2016
DIRECTION
OF OVER
FLOW
MAIN ....___
DRAINAGE
CHANNEL
10 | P a g e
idealized watershed:
Y = 2X(1.5 — Z)(2K — X)/(2K — 1) (2-1)
where K is an upper limit on the watershed shape factor. Guo and Urbonas (2007) recommend that K
be between 4 and 6 and note that a value of 4 is used by Denver’s Urban Drainage and Flood Control
District. Once Y is determined, the equivalent width W for the idealized watershed is computed
as YL.
Applying this approach:
X = (A • 43,560 ft2/acre) / (L2)
Z = Am/A
Z = skew factor, 0.5 ≤ Z ≤ 1,
Am = larger of the two areas on each side of the channel A = total area.
W = L • Y
This width value is considerably lower than those derived from direct estimates of either the
longest flow path length or the drainage channel length. As a result, it would most likely produce a
longer time to peak for the runoff hydrograph.
Slope
This is the slope of the land surface over which runoff flows and is the same for both the pervious
and impervious surfaces. It is the slope of what one considers being the overland flow path or its
area-weighted average if there are several paths in the sub-catchment.
Imperviousness
This is the percentage of sub-catchment area covered by impervious surfaces such as sidewalks and
roadways or whatever surfaces that rainfall cannot infiltrate.
Roughness Coefficient
The roughness coefficient reflects the amount of resistance that overland flow encounters as it runs
off of the sub-catchment surface. For this site we have taking into account the pre-existing
conditions of the site which would have included small vegetation with scattered shrubs, to give a
manning’s value of 0.038; which would be represented as a poor mowed grass. Per Yen (2001) (See
Table 3-5 from the Storm Management Model Reference Manual Volume I-Hydrology (Revised))
11 | P a g e
Infiltration Model
The pre-development condition is primarily empty land with moderate vegetation cover. In the
model, clay soil was used for the post-development condition and the pre-development condition
for a conservative approach (yield to a higher runoff). Infiltration of rainfall from the pervious area
of a sub-catchment into the unsaturated upper soil zone can be described using three different
infiltration models: Horton, Green-Ampt, and Curve Number. There is no general agreement on
which method of these three is the best.
Table-3-S fmates El Malllililiu ' r ougbn ocfficicnt for overland Dow
Sonrce Grmtm:I Cover II Range
Smooth m;;plilall O.ol
Crawford a d Linsley Aspliiall of concrete paving 0.014
0966 Packed day 0,03
Light h.111" 0.20
Dense turf 0.35
Dense shn1bbery and forest liHer 0,4
Concrete or a~phall O.oll 0.010•0.013
Engman O 986)1, Bare sand O.olO O.ol -0.016
Gravelecl surface 0.02 O.ol2-0.03
Bare day-loam (erocled) 0,02 O.ol2-0.033
Ranfl:e (natural} 0,13 O.ol -0.32
Bi1i.1egrass sod 0,45 0,39-0.63
Short ,grass prairie 0,15 0.10-0.20
Bem111da grass 0,41 0.30-0.48
Y n (2001)<' S moo'lh asphalt pave.menl 0,012 0.010-0.015
Smooth impervious surface 0.013 O.ol 1-0.015
Tar an.d sa11d pavement 0,014 0,012-0.016
Conct'ete i,ave1nen1. 0.017 O.Ol4-0.020
Rou.i1h in1Dervious surface 0.019 O.OLS-0.023
S moo1h bare packed soi.I 0,021 O.ot7~0.025
Mockrnk: bare packed soil 0,030 0.025-0,.D35
Rough barn packed soi.I 0,038 0.032-0.045
Gravels.oil 0.032 0.025-0.()45
Mowed poor gJass 0,038 0.030-0.045
A vern2.e-2n1ss, dosel y d im)e<I sod 0.050 0.040..0.060
Pasture 0,055 0,040..0.070
Timberland 0,090 0.060-0.120
DenSefl:rass 0,090 0,060•0.120
Shrnbs and bushes 0.120 0.080-0 .. I BO
Business. land 11..,;,e 0.022 0.014-0.035
Semi-business hmd use-0.035 0.022-0.050
Industrial land use 0,035 0.020-0.050
Dense .residential land use 0,040 0.025-0.060
S ulntroa11 ire:sickntiaJ fand u:;e 0,055 0.030-0,080
Parks and fawns 0.075 0.040•0 .. 120
"Obtai m::d by c.alibrnlion of Stanford W aler:shcd Model,
'ompme-d b , ngman ( l 986 by k:inemati ave and torage analysis of measured
rainfol 1-runo ff d111.a,
"Compuh:d 0.11 basis of k.inemalic wave analys.is.
Source: Storm 'Water Management Model Reference Manual Volume I -rlydroJogy (Revised), Jonu.ory
2016
12 | P a g e
The Green-Ampt method was chosen to calculate the infiltration of the pervious areas based on the
availability of data for this project. It is invoked when editing the infiltration property of a sub-
catchment.
Table 2.1 – Soil Infiltration Parameter
SWMM
Parameter
Name
Unit
Range
Use in San Diego
Infiltration Method HORTON
GREEN_AMPT
CURVE_NUMBER
GREEN_AMPT
Suction Head Inches 1.93 – 12.60 presented Hydrologic Soil Group A: 1.5
(Green-Ampt) in Table A.2 of SWMM Hydrologic Soil Group B: 3.0
Manual Hydrologic Soil Group C: 6.0
Hydrologic Soil Group D: 9.0
Conductivity Inches per hour 0.01 – 4.74 presented Hydrologic Soil Group A: 0.3
(Green-Ampt) in Table A.2 of SWMM Hydrologic Soil Group B: 0.2
Manual by soil texture Hydrologic Soil Group C: 0.1
class Hydrologic Soil Group D: 0.025
0.00 – Ç0.45 presented
in Table A.3 of SWMM Note: reduce conductivity by 25% in
the post-project condition when
native soils will be compacted.
Conductivity may also be reduced by
25% in the pre-development
condition model for redevelopment
areas that are currently concrete or
asphalt but must be modeled
according to their underlying soil
characteristics. For fill soils in postproject
condition, see Section G.1.4.3.
Manual by hydrologic
soil group
Initial Deficit The difference between Hydrologic Soil Group A: 0.30
(Green-Ampt) soil porosity and initial Hydrologic Soil Group B: 0.31
moisture content. Hydrologic Soil Group C: 0.32
Based on the values Hydrologic Soil Group D: 0.33
provided in Table A.2
of SWMM Manual, the Note: in long-term continuous
range for completely simulation, this value is not important
dry soil would be 0.097 as the soil will reach equilibrium after
to 0.375 a few storm events regardless of the
initial moisture content specified.
Groundwater yes/no yes/no NO
LID Controls Project Specific
Snow Pack Not applicable to hydromodification
13 | P a g e
Land Uses management studies
Initial Buildup
Curb Length
Source: Model BMP Design Manual San Diego Region Appendices, February 26, 2016
LID controls
Utilizing LID controls within a SWMM project is a two-step process that:
- Creates a set of scale-independent LID controls that can be deployed throughout the
study area,
- Assign any desired mix and sizing of these controls to designated sub-catchments.
The LID control type that was selected was a bio-filtration cell that contains vegetation grown in
an engineered soil mixture placed above a gravel drainage bed. Bio-filtration provides storage,
infiltration (depending on the soil type) and evaporation of both direct rainfall and runoff
captured from surrounding areas. For this project, we do not allow infiltration to the
existing/filled soil.
14 | P a g e
SECTION III. CONTINUES SIMULATION OPTIONS
Simulation Dates
These dates determine the starting and ending dates/times of a simulation and are chosen based on the
rain data availability.
Start analysis on 01/03/1951
Start Reporting on 01/03/1951
End Analysis on 05/23/2008
Time Steps
The Time Steps establish the length of the time steps used for runoff computation, routing computation
and results reporting. Time steps are specified in days and hours: minutes: seconds except for flow
routing which is entered as decimal seconds.
Climatology
-Evaporation Data
The available evaporation data for San Diego County is taken from Table G.1-1: Monthly Average
Reference Evapotranspiration by ETo Zone for use in SWMM Models for Hydromodification
Management Studies in San Diego County CIMIS Zone 4 (in/day).
January February March April May June
0.05 0.09 0.13 0.19 0.25 0.29
July August September October November December
0.30 0.27 0.21 0.14 0.08 0.05
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SECTION IV. BIO-FILTRATION AS LID CONTROL
LID controls are represented by a combination of vertical layers whose properties are defined on a per-
unit-area basis. This allows an LID of the same design but differing coverage area to easily be placed
within different sub-catchments of a study area. During a simulation, SWMM performs a moisture
balance that keeps track of how much water moves between and is stored within each LID layer. If the
bio-filtration basin is full and water is leaving the upper weir, the flow is divided in two flows: the lower
flow discharging from the bottom orifice directly draining to the point of compliance and the upper flow
is routed at the top of the bio-filtration basin and after routing, discharged to the point of compliance. In
this project, we used 100% of the area of this specific sub-catchment for bio-filtration.
1. Surface
Storage Depth
When confining walls or berms are present, this is the maximum depth to which water can pond above
the surface of the unit before overflow occurs (in inches). In this project, storage depths vary.
Vegetation Volume Fraction
It is the fraction of the volume within the storage depth that is filled with vegetation. This is the volume
occupied by stems and leaves, not their surface area coverage. Normally this volume can be ignored, but
may be as high as 0.1 to 0.2 for very dense vegetative growth. Based on our visual observation in the
field, the average type of vegetation for this site is a low-density vegetation type. Therefore, we used 0.1
for the vegetation volume fraction assuming type of vegetation used is a low-density type.
Surface Roughness
Manning's n value for overland flow over a vegetative surface.
Surface Slope
Slope of porous pavement surface or vegetative swale (percent).
2. Soil
Thickness
The thickness of the soil layer in inches. We used a typical value of 18 inches soil thickness for a
biofiltration.
The volume of pore space relative to total volume of soil (as a fraction). We designed it with a soil mix
porosity of 0.40 maximum for a good percolation rate (Countywide Model BMP Table B1 – Soil Porosity
Appendix A: Assumed Water Movement Hydraulics for Modeling BMPs).
Field Capacity
Volume of pore water relative to total volume after the soil has been allowed to drain fully (as a
fraction). We used 0.2 for this soil. Below this level, vertical drainage of water through the soil layer does
not occur. (See Table 1 – Soil Infiltration Parameter).
16 | P a g e
Wilting Point
Volume of pore water relative to total volume for a well-dried soil where only bound water remains (as
a fraction). The moisture content of the soil cannot fall below this limit. We assumed the minimum
moisture content within this bio-filtration soil is 0.1.
Conductivity
Hydraulic conductivity for the fully saturated soil is 5 inches/hour. This is a design minimum value for
percolation rate.
Conductivity Slope
Slope of the curve of log (conductivity) versus soil moisture content (dimensionless). Typical values
range from 5 for sands to 15 for silty clay. We designed this soil to have a very good percolation rate
therefore the conductivity slope is 5.
Suction Head
The average value of soil capillary suction along the wetting front (inches). This is the same parameter as
used in the Green-Ampt infiltration model. Table 1 was utilized to determine the capillary of the soil mix
top layer of a bio-filtration system. The suction head will be 1.5 inches.
3. Storage Layer
The Storage Layer page of the LID Control Editor describes the properties of the crushed stone or gravel
layer used in bio-filtration cells as a bottom storage/drainage layer. The following data fields are
displayed:
Height
This is the thickness of a gravel layer (inches). Crushed stone and gravel layers are vary ranging from 12
to 36 inches thick. A table is provided to summarized the BMP configurations.
Void Ratio
The volume of void space relative to the volume of solids in the layer. Typical values range from 0.5 to
0.75 for gravel beds. Note that porosity = void ratio / (1 + void ratio). We designed this void ratio to have
a value of 0.67.
Seepage Rate
The rate at which water infiltrates into the native soil below the layer (in inches/hour). This would
typically be the Saturated Hydraulic Conductivity of the surrounding sub-catchment if Green-Ampt
infiltration is used. Since the liner beneath the gravel layer is proposed, the seepage rate is assumed to
be 0 in/hr.
Clogging Factor
Total volume of treated runoff it takes to completely clog the bottom of the layer divided by the void
volume of the layer. For south east bio-filtration, a value of 0 was used to ignore clogging since the
system does NOT consider infiltration to the native soils. Clogging progressively reduces the Infiltration
Rate in direct proportion to the cumulative volume of runoff treated and may only be of concern for
infiltration trenches with permeable bottoms and no under drains. We assumed zero for the clogging
factor since the infiltration rate is not considered.
17 | P a g e
4. Underdrain Layer
LID storage layers can contain an optional underdrain system that collects stored water from the bottom
of the layer and conveys it to a conventional storm drain. The Underdrain page of the LID Control Editor
describes the properties of this system. It contains the following data entry fields:
Drain Coefficient and Drain Exponent
Coefficient C and exponent n that determines the rate of flow through the underdrain as a function of
height of stored water above the drain height. The following equation is used to compute this flow rate
(per unit area of the LID unit):
q = C(h-Hd)n
where q is the outflow (in/hr), h is the height of stored water (inches), and Hd is the drain height. A
typical value for n would be 0.5 (making the drain act like an orifice.
Drain Offset Height
Height of any underdrain piping above the bottom of a storage layer (inches). In this project, this value
was set to 0 as the underdrain piping is at the bottom of the storage layer.
Note:
q = C(h-Hd)n
C=𝐶𝑜𝐴𝑜
√2𝑔
𝐴× 120.5 × 3600
18 | P a g e
SECTION V. RUNNING THE SIMULATION
In general, the Run time will depend on the complexity of the watershed being modeled, the routing
method used, and the size of the routing time step used. The larger the time steps, the faster the
simulation, but the less detailed the results.
Model Results
SWMM’s Status Report summarizes overall results for the 58-yr simulation. The runoff continuity error is
-2.67% and the flow routing continuity error is 0.00%. When a run completes successfully, the mass
continuity errors for runoff, flow routing, and pollutant routing will be displayed in the Run Status
window. These errors represent the percent difference between initial storage + total inflow and final
storage + total outflow for the entire drainage system. If they exceed some reasonable level, such as 10
percent, then the validity of the analysis results must be questioned. The most common reasons for an
excessive continuity error are computational time steps that are too long or conduits that are too short.
In addition to the system continuity error, the Status Report produced by a run will list those nodes of
the drainage network that have the largest flow continuity errors. If the error for a node is excessive,
then one should first consider if the node in question is of importance to the purpose of the simulation.
If it is, then further study is warranted to determine how the error might be reduced.
The SWMM program ranks the partial duration series, the exceedance frequency and the return period.
They are computed using the Weibull formula for plotting position. See the flow duration curve and
peak flow frequency on the following pages.
19 | P a g e
SECTION VI. RESULT ANALYSIS
Development of the Flow Duration Statistics
The flow duration statistics are also developed directly from the SWMM binary output file. It should be
noted right from the start that the “durations” that we are talking about in this section have nothing to
do with the “storm durations” presented in the peak flow statistics section. Other than using the same
sequence of letters for the word, the two concepts have nothing to do with each other and the reader is
cautioned not to confuse the two. The goal of the flow duration statistics is to determine, for the flow
rates that fall within the hydromorphologicaly significant range, the length of time that each of those
flow rates occur. Since the amount of sediment transported by a river or stream is proportional to the
velocity of the water flowing and the length of time that velocity of flow acts on the sediment, knowing
the velocity and length of time for each flow rate is very useful.
Methodology
The methodology for determining the flow duration curves comes from a document developed by the
U.S. Geological Survey (USGS). The first stop on the journey to find this document was a link to the
USGS water site (http://www.usgs.gov/water/). This link is found in Appendix E (SDHMP Continuous
Simulation Modeling Primer), found in the County Hydromodification Management Plan1. On this web
site a search for “Flow Duration Curves” leads to USGS Publication 1542-A, Flow-duration curves, by
James K. Searcy 1959 (http://pubs.er.usgs.gov/publication/wsp1542A). In this publication the
development of the flow duration curves is discussed in detail.
In Pub 1542-A, beginning on page 7 an example problem is used to illustrate the compilation of data
used to create the flow duration plots. A completed form 9-217-c form shows the monthly tabulation of
flow rates for Bowie Creek near Hattiesburg, Miss. For each flow range the number of readings is
tabulated and then the total number of each flow rate is totaled for the year. It should be noted that
while this example is for a stream with a minimum flow rate of 100cfs, for the purposes of run-off
studies in Southern California the minimum flow rate of zero (0) cfs is the common low flow value. Once
each of the year’s data has been compiled the summary numbers from each year are transferred to
form 9-217-d. On this form the total number of each flow rate is again totaled and the percentage of
time exceeded calculated (as will be explained later under the discussion of our calculations). Once the
data has been compiled a graph of Discharge Rate vs. Percent Time Exceeded is developed. As will be
explained in the next section, the use of these curves leads to the amount of time each particular flow
can be expected to occur (based on historical data).
How to Read the Graphs2
Figure 7 shows a flow duration curve for a hypothetical development. The three curves show what
percentage of the time a range of flow rates are exceeded for three different conditions: pre-project,
1 FINAL HYDROMODIFICATION MANAGEMENT PLAN, Prepared for County of San Diego, California, March 2011, by
Brown and Caldwell Engineering of San Diego.
(http://www.projectcleanwater.org/images/stories/Docs/LDS/HMP/0311_SD_HMP_wAppendices.pdf)
2 The graph and the explanation were taken directly from Appendix E of the Hydromodification Plan
20 | P a g e
post-project and post-project with storm water mitigation. Under pre-project conditions the minimum
geomorphically significant flow rate is 0.10cfs (assumed) and as read from the graph, flows would equal
or exceed this value about 0.14% of the time (or about 12 hours per year) (0.0014 x 365days x 24
hour/day). For post-project conditions, this flow rate would occur more often – about 0.38% of the time
(or about 33 hours per year) (0.0038 x 365days x 24 hour/day). This increase in the duration of the
geomorphically significant flow after development illustrates why duration control is closely linked to
protecting creeks from accelerated erosion.
Development of Flow Duration Curves
The first step in developing the flow duration curves is to count the number of occurrences of each flow
rate. This is done by first rounding every non-zero flow value to an appropriate number of decimal
places (say two places). This in effect groups each flow into closely related values or “bins” as they are
referred to in publication 9-217d. Then the entire runoff record is queried for each value and the
number of each value counted. The next step is to enter the results of the query into a grid patterned
after form 9-217d. The data is entered in ascending order starting with the lowest flow first. The grid is
composed of four columns. They are (from left to right) Discharge Rate, Number of Periods (count),
Total Periods Exceeding (the total number of periods equal to or exceeding this value), and Percent Time
Exceeded. Starting at the top row (row 1), the flow rate (which is often times zero) is entered with the
corresponding number of times that value was found. The next column is the total number of values
greater than or equal to that flow rate. For the first flow rate point, by definition all flow rate values are
greater than or equal to this value, therefore the total number of runoff records of the rainfall record is
entered here. The final column which is the percent of time exceeded is calculated by dividing the total
Figure 7 Flow Duration Series Statistics for a Hypothetical Development Scenario
80 ~---~---~---~~---~---~I~---~---~---~
----+-lmper.i, s f lm1• cfs)
------Pre-Project Floor (c,-,,
------Post-Project -iga :ed Flo1111 .r/
Pre-Project .2Q5
- -Pre·-Projeci Q1
D.25
%.T i'm e Eicceededl
21 | P a g e
periods exceeded by the total number of periods in the study. For the first row this number should be
100%3
For the next row (row 2), the flow rate, and the flow rate count are entered. The total number of
periods exceeding for row 2 is calculated by subtracting Number of Periods of row 1 from the Total
Periods Exceeding of line 1. This result is entered in the Total Periods Exceeding on row 2. As was the
case for line 1, the final column is calculated by dividing the total periods exceeded by the total number
of periods in the study. For the second row this number should be something less than 100% and
continually decrease as we move down the chart. If all the calculations are correct, then everything
should zero out on the last line of the calculations.
The final step in developing the flow duration curves is to make a plot of the Discharge Rate vs. the
Percent Time Exceeded. For the purposes of this report, the first value corresponding to the zero flow
rate is not plotted allowing the graph to be focused on the actual flow rate values.
The Flow Duration Analysis
The Peak Flow Statistics analysis is composed of the following series of files:
1. The Flow Duration Plot
2. Comparison of the Un-Mitigated Flow Duration Curve to the Pre-Development Curve (Pass/Fail)
3. Comparison of the Mitigated Flow Duration Curve to the Pre-Development Curve (Pass/Fail)
4. The calculations for the Pre-Development flow duration curve development (USGS9217d)
5. The calculations for the Post-Development flow duration curve development (USGS9217d)
6. The calculations for the Mitigated flow duration curve development (USGS9217d)
The Flow Duration Plot
The Flow Duration Curves Plot is the plotting of all three (pre, un-mitigated and mitigated) sets of
Discharge Rate vs. the Percent Time Exceeded data point pair lists. In addition to these curves
horizontal lines are plotted corresponding to the Q10 and Qlf (low flow threshold) values. Within the
geomorphically significant range (Q10 – Qlf) one can see a visual representation of the relative positions
of the flow duration curves. The flow duration curves are compared in an East/West (horizontal)
direction to compare post development Discharge Rates to pre-development Discharge Rates. The pre-
development curve is plotted in blue, the unmitigated curve is plotted in red, and the mitigated curve is
plotted in green. As long as the post development curve lies to the left of the pre-development curve
(mostly4), the project meets the peak flow hydromodification requirements.
Pass/Fail comparison of the curves
The next two sets of data are the point by point comparison of the post-development curve(s) and the
pre-development curve. The Pass/Fail table is helpful in determining compliance since the plotted lines
can be difficult to see at the scales suitable for use in a report. Each point on the post- development
curve has a corresponding “Y” value (Flow Rate), and “X” value (% Time Exceeded). For each point on
4 See hydromodification limits for exceedance of pre-development values
22 | P a g e
the post development curve, the “Y” value is used to interpolate the corresponding Percent Time
Exceeded (X) value from the pre-development curve. Then the Post-development Percent Time
Exceeded value is compared to the pre-development Percent Time Exceeded value. Based on the
relative values of each point, pass/fail criteria are determined point by point.
For each set of data, the upper right hand header value shows the name of the file being displayed (ex.
flowDurationPassFailMitigated.TXT). The first line of the file shows the name of the SWMM output file
(*.out). The next line shows the time stamp of the SWMM file that is being analyzed. The time stamps
of all of the report files should be within a minute or two of each other, otherwise there may have been
tampering with the files. Each report run creates and prints all of the files and reports at one time so all
the time stamps should be very close.
The first column is the zero based number of the point. The next two columns show the post
development “X” and “Y” values. The next column shows the value interpolated between the two
bounding points on the pre-development curve. The next three columns show the true or false values
of the comparison of the two “X” values. The last column shows the resultant pass or fail status of the
point. There are three ways a point can pass. They are:
1. Qpost being outside of the geomorphically significant range Qlf to Q10
2. Qpost being less than Q pre
3. Qpost being less than 110% of the value of Qpre if the point is between Qlf and Q10
There are two ways that a point can fail. They are:
1. Qpost being greater than 110% of Qpre if the point is between Qlf and Q10
2. If more than 10% of the points are between 100% and 110% of Qpre for the points
between Qlf and Q10
A quick scan down the last column will quickly tell if there are any points that fail.
At the bottom of each set of data are the date stamp of the report to the left, and to the right is the
page number/number of pages for the specific set of data (not the pages of the report!). Each new set
of data has its own page numbering. Between the file name in the header row and the page numbering
in the footer row, the engineer can readily scan the document for the data of interest.
Plan Check Suggestions
As was described under the peak flow section, is the responsibility of the reviewing agency to confirm
that the data sets presented are valid results from consistent calculations, and that any and all results
can be duplicated by manual methods and achieve the same results. In light of these goals, the plan
checker is invited to consider the following tasks as part of the plan check process.
Compare the Data Stamps for Each of the Statistics Files Used In This Analysis.
As was described in the Peak Flows section, all report files should have time stamps that are nearly
identical. If the time values are more than a few minutes apart then the potential for inconsistent
results files should be investigated.
23 | P a g e
Verify the Flow Rate Counts
For each of the pre, un-mitigate and mitigated flow duration tables, a few randomly selected flow value
counts should be checked against the values taken directly from the SWMM file. This can be done by
opening the corresponding SWMM file, selecting the outfall node, selecting Report>Table>By Object,
Setting the time format to Date/Time, selecting the appropriate node value, and clicking the OK button
to generate a table of the date/time/Total Inflow values. Next step is to click in the left most header
row of the SWMM table which will select the entire table. Now from the main menu select Edit>Copy
To>Clipboard. Now open a new blank sheet in MS Excel (or suitable spread sheet program) select cell
A1 and paste the results from the clipboard into the spread sheet. Now sort the values based on the
Total Inflow column. This will group all the flow values together enabling the number of occurrences of
each value to be counted. At this point the a few (or all) of the counts on the various USGS9217d.txt
files can be verified.
Manually Verify That the Percent Exceeded Values (form USGS9217d) are Correctly Calculated
The discharge rates and counts are confirmed as was described above. The top row should be the
smallest runoff value (0.00cfs usually). Total Periods Exceeding of the first line should be the total
number of rainfall records in the study. The percentage of Time Exceeding should be the total periods
Exceeding divided by the total number of rainfall records in the study (100% for the first line). For each
successive discharge rate, the total periods exceeding for the current line should be the total periods
exceeding from the line above minus the number of periods from the line above. The number of
periods and the number of periods exceeding should zero out at the last line.
Compare Plotted Curves to Table Data
Randomly check a few of the plotted points against the values verified above.
Verify by Observation that the plotted values of Q10 and Qlf are reasonable.
Verify that the correct values for each of these return periods are plotted correctly on the graph.
Development of the Peak Flow Statistics
The peak flow statistics are developed directly from the binary output file produced by the SWMM
program. The site is modeled three ways, Pre-Development, Post-Development-Unmitigated, and Post-
Development-Mitigated. For each of these files a specific time period differentiating distinct storms is
chosen. The SWMM results are extracted and each flow value is queried. The majority of the values for
Southern California sites are zero flow. As each successive record is read, as soon as a non-zero value is
read the time and flow value of that record are recorded as the beginning of an event. The first record is
automatically recorded as the “tentative” peak value. As each successive non-zero value is read and the
successive flow value is compared to the peak value and the greater value is retained as the peak value
of the storm. As soon as a successive number of zero values equal to the predetermined storm
separation value, then the time value of the last non-zero value is recorded as the end of the storm, the
duration of the storm is the difference between the end time and the start time, and the peak value is
recorded as the highest flow value between the start and end times.
Once the entire SWMM output file is read all of the distinct storm events will have been recorded in a
special list. The storms will be in the order of their occurrence. To develop the peak flow statistics table
the first step is to sort the storms in descending order of the peak flow value. Once the list is sorted
then the relative rank of each storm is assigned with the highest ranking storm being the storm with the
highest peak flow. There are several methods that can be used to determine which storm should be
24 | P a g e
ranked above another equally valued storm. For the purposes of these studies an Ordinal ranking is
used so that each storm has a unique rank number. Where two or more storms have equal flow values,
the earlier storm is assigned the higher rank. This is done consistently throughout the storm record.
Since we are only looking at peak flow statistics, it is assumed that the relative ranking of individual (but
equal) storms is irrelevant to the calculations.
The exceedance frequency and return period are both computed using the Weibull formula for plotting
position. Therefore, for a specific event the exceedance frequency F and the return period in years T are
calculated using the following equations5:
F=m/(nR+1) and T=n+1/m
where m is the event’s rank, nR is the total number of events and n is the number of years under
analysis.
Once the Peak flow statistics table is complete, a plot of Return Frequency vs. peak flow is created. All
three conditions (pre, post and mitigated) are plotted on the same plot.
The Peak Flow Statistics Analysis
The Peak Flow Statistics analysis is composed of the following series of files:
1. The Peak Flow Frequency Plot
2. The Comparison of the Un-Mitigated Peak Flow Curve to the Pre-Development Curve (Pass/Fail)
3. The Comparison of the Mitigated Conditions Curve to the Pre-Development Curve (Pass/Fail)
4. The Peak Flow Statistics Calculation for the Pre-Development Curve.
5. The Peak Flow Statistics Calculation for the Un-Mitigated Curve.
6. The Peak Flow Statistics Calculation for the Mitigated Curve.
The Peak Flow Frequency Plot
The Peak Flow Frequency Curves are the plotting of all three (Pre, Un-Mitigated and Mitigated) sets of
return Period vs peak flow data point pair lists. In addition to these curves horizontal lines are plotted
corresponding to the Q10, Q5, Q2 and Qlf (low flow threshold) values. Within the geomorphically
significant range (Q10 – Qlf) one can see a visual representation of the relative positions of the peak flow
curves. The peak flow curves are compared in a North/South (vertical) direction to compare post
development peak flows to pre-development flows. The Pre-Development curve is plotted in blue, the
unmitigated curve is plotted in red, and the mitigated curve is plotted in green. As long as the post
development curve lies below the pre-development curve (mostly6), the project meets the peak flow
hydromodification requirements.
Pass/Fail comparison of the curves
The next two sets of data are the point by point comparison of the post-development curve(s) and the
pre-development curve. The Pass/Fail table is helpful in determining compliance since the plotted lines
can be difficult to see at the scales suitable for use in a report. Each point on the post- development
curve has a corresponding “X” value (Recurrence Interval), and “Y” value (Peak Flow). For each point on
the post development curve, the “X” value is used to interpolate the corresponding peak flow value
from the pre-development curve. Then the Post-development peak flow value is compared to the pre-
5 Pg 169-170 STORM WATER MANAGEMENT MODEL APPLICATIONS MANUAL, EPA/600/R-09/000 July 2009
6 See hydromodification limits for exceedance of pre-development values
25 | P a g e
development peak flow value. Based on the relative values of each point, pass/fail criteria are
determined point by point.
For each set of data, the upper right hand header value shows the name of the file being displayed (ex.
peakFlowPassFailMitigated.TXT). The first line of the file also shows this value. The next line shows the
time stamp of the file that is being analyzed. The time stamps of all of the report files should be within a
minute or two of each other, otherwise there may have been tampering with the files. Each report run
creates and prints all of the files and reports at one time so all the time stamps should be very close. It
should be noted that the SWMM.out files will not have related time stamps since each file is developed
independently.
The first column is the zero based number of the point. The next two columns show the post
development “X” and “Y” values. The next column shows the value interpolated between the two
bounding points on the pre-development curve. The next three columns show the true or false values
of the comparison of the two “Y” values. The last column shows the resultant pass or fail status of the
point. There are three ways a point can pass. They are:
1. Point is outside of the geomorphically significant range Q10 – Qlf
2. Qpost being less than Q pre
3. Qpost being less than 110% of the value of Qpre if the point is between Q5 and Q107
There are four ways that a point can fail. They are:
1. Qpost being greater than Qpre if the point is between Qlf and Q5
2. Qpost being greater than 110% of Qpre if the point is between Qlf and Q10
3. If more than 10% of the points are between 100% and 110% of Qpre for the points between Q5
and Q10
4. If the frequency interval for points > 100% of Qpre is greater than 1 year for the points between
Q5 and Q10
A quick scan down the last column will quickly tell if there are any points that fail.
At the bottom of each set of data are the date stamp of the report to the left, and to the right is the
page number/number of pages for the specific set of data (not the pages of the report!). Each new set
of data has its own page numbering. Between the file name in the header row and the page numbering
in the footer row, the engineer can readily scan the document for the data of interest.
The Peak Flow Statistics Calculations
There are three sets of data for the Peak Flow Statistics calculations (Pre-Development, Un-Mitigated,
and Mitigated). As was the case for the pass/fail data, the upper right hand corner of each sheet has the
file name. The first row of the data is the SWMM file name. The second row is the SWMM file time
stamp of the file being analyzed. The 4th, 5th, and 6th rows are the calculated values for Q10, Q5, and Q2.
These values are derived by linear interpolation between the nearest bounding points in the listing.
While the relationship between the points in the peak flow analysis is not technically a linear
relationship, the error introduced in using linear interpolation between such relatively close data points
7 See section on how a point can fail point number 3 hereon
26 | P a g e
is assumed to be irrelevant. Finally, the footer row shows the report time and the page/number of
pages of the data set.
As was previously discussed, each storm listed was determined by reading the flow values directly from
the binary output file from the SWMM program. The storms were then sorted in descending order of
peak flow values. Then each storm was assigned a unique rank, then the Frequency and Return Period
were calculated using Weibull formulas. Every discharge value for the entire rainfall record is listed in
each of these lists. It should be noted that the derivation of these peak flow statistics values use full
precision (i.e. no rounding off) of the SWMM output values. Since the precision of the calculations may
not be the same as the SWMM program uses, and also the assignment of rank to values of equal peak
flow value may differ slightly from the way SWMM calculates the tables, minor variances in the data
values and/or the order of storms can be expected.
Finally, as was previously stated, the values of the Return Period were plotted vs. the peak flow values
to develop the peak flow frequency curves.
Plan Check Suggestions
As is the responsibility of the reviewing agency, any and all methods should be considered to verify that
the SWMM analysis adequately models the site as far as hydrologic discharge is concerned, and that the
data sets presented are valid results from consistent calculations, and that any and all results can be
duplicated by manual methods and achieve the same results. In light of these goals, the plan checker is
invited to consider the following tasks as part of the plan check process.
Compare the Data Stamps for Each of the Statistics Files Used In This Analysis.
For each set of calculations and report files, the first step of the process is to list out all the files in the
report folder and delete those files. The very first step leaves the reports folder completely empty.
Then as each successive step is performed, the results file is placed in the reports folder. Once all of the
results files are complete, then the report file is compiled using the data directly from the files placed in
the results folder. This means that the time stamps on each of the report files in the report should be
within a minute or two depending on the speed of the computer. If the time values are more than a few
minutes apart then the potential for inconsistent results files should be investigated.
Verify A Few Random Storm Statistics
For each of the Pre, Un-mitigate and Mitigated peak flow statics tables, a few randomly selected storms
should be checked against the values taken directly from the SWMM file. This can be done by opening
the corresponding SWMM file, selecting the outfall node, selecting Report>Table>By Object, Setting the
time format to Date/Time, selecting the appropriate node value, and clicking the OK button to generate
a table of the date/time/Total Inflow values. Now scroll down the list to the start date and time of the
randomly selected storm. Verify that the start date, end date, and the highest flow value between the
start and end date correspond to the values shown in the statistics table. Do this for a few storm to
verify that the data corresponds to the SWMM output file. Verify by hand a few of the frequency and
return period values.
Compare Plotted Curves to Table Data
Randomly check a few of the plotted points against the values found in the Peak Flow Frequency Tables.
27 | P a g e
Verify by Observation that the values of Q10, Q5, Q2 and Qlf are reasonable.
For each value shown on the reports, verify that the value shown for say Q10 is in between the next
higher return period and the next lower period. Also verify that the correct values for each of these
return periods are plotted correctly on the peak flow frequency graph.
Manually Verify That the Pass Fail Table Is Correctly Calculated
Select at random several points on each of the pass/fail tables to verify that the values for post X/Y and
interpolated Y look reasonable. Also check that the various test results are shown accurately in the
chart and also the final pass/fail result looks accurate.
Drawdown Time of Bio-filtration Surface Ponding
The drawdown time for hydromodification flow control facilities was calculated using the attached draw
down calculations included in the SWMM Report
VII. SUMMARY AND CONCLUSION
Hydromodification calculations were performed utilizing continuous simulation to size storm water
control facilities. SWMM (Storm Water Management Model) version 5.0 distributed by USEPA was used
to generate computed peak flow recurrence and flow duration series statistics.
There are several tributary areas treated by 6 biofiltration BMPS labeled as BMP-A, B, C, D, E & F (Best
Management Practices) with a total tributary area of approximately 2.05 acres. The areas were grouped
based on its outfall and were analyzed for pre-development and mitigated post-development
conditions.
The analyzed SWMM runs attached show that the proposed bio-filtration facilities provided with variety
of orifice flow control at the base of the gravel storage configured as shown in Figure 1 is in compliance
with the HMP and BMP Manual.
For the Mitigated Conditions:
Peak Flow Conditions PASS
Flow Duration Conditions PASS
The Mitigated Conditions peak flow frequency curve is composed of 911 points. Of the points, 3 point(s)
are above the flow control upper limit (Q10), 789 point(s) are below the low flow threshold value (Qlf).
Of the points within the flow control range (Qlf to Q10), 119 point(s) have a lower peak flow rate than
pre-development conditions. These points all pass. There are no points that failed, therefore the peak
flow requirements have been met.
The Mitigated Conditions flow duration curve is composed of 100 flow bins (points) between the upper
flow threshold (cfs) and lower flow threshold (cfs). Each point represents the number of hours where
the discharge was equal to or greater than the discharge value, but less than the next greater flow value.
Comparing the post-development flow duration curve to the pre-development curve, 97 point(s) have a
lower duration than pre-development conditions, and 1 point(s) have a duration that exceeds the pre-
development by less than 10%, and for less than 10% of the curve length. These points all pass. There
are no points that failed, therefore the flow duration requirements have been met.
28 | P a g e
Therefore, this study has demonstrated that the proposed optimized bio-filtration basin is sufficient to
meet the current HMP and BMP criteria (See following Attachments A, & B).
Excel Engineering
V:\22\22081\Engineering\GPIP\Storm\Working Files\Hydmod\Report\report parts\Statistics Reports\POC\Statistics
Results-POC.pdf
6/4/2025 11:01:52 AM software version: 1.0.7318.27220
STATISTICS ANALYSIS OF THE
SWMM FILES FOR:
DISCHARGE NODE: POC
ANALYSIS DETAILS
Stream Susceptibility to Channel Erosion: High
Low Flow Threshold = (0.1)Q2 = (0.1)0.994 = Qlf = 0.0994 (cfs)
Flow Control Upper Limit = Q10 = 1.563 (cfs)
Assumed time between storms (hours): 24
PRE-DEVELOPMENT SWMM FILE
SWMM file name: V:\22\22081\Engineering\GPIP\Storm\Working Files\Hydmod\Current\22-081 PRE-DEV.out
SWMM file time stamp: 5/15/2023 1:39:32 PM
Selected Node to Analyze: POC
POST-DEVELOPMENT MITIGATED SWMM FILE
SWMM file name: V:\22\22081\Engineering\GPIP\Storm\Working Files\Hydmod\Current\22081 POST-PC1 -
Copy.out
SWMM file time stamp: 6/3/2025 6:29:35 PM
Selected Node to Analyze: POC
MITIGATED CONDITIONS RESULTS
For the Mitigated Conditions:
Peak Flow Conditions PASS
Flow Duration Conditions PASS
The Mitigated Conditions peak flow frequency curve is composed of 550 points. Of the points, 0 point(s) are above
the flow control upper limit (Q10 = 1.5627 (cfs)), 485 point(s) are below the low flow threshold value (Qlf =
0.09940 (cfs)). Of the points within the flow control range (Qlf to Q10), 65 point(s) have a lower peak flow rate
than pre-development conditions. These points all pass. There are no points that failed, therefore the peak flow
requirements have been met.
The Mitigated Conditions flow duration curve is composed of 100 flow bins (points). Each point represents the
number of hours where the discharge was equal to or greater than the discharge value, but less than the next
greater discharge value. Within the flow control range, comparing the post-development flow duration curve to
the pre-development flow duration curve, 100 post-development curve point(s) have a lower flow duration than
pre-development conditions. These points all pass. There are no points that failed, therefore the flow duration
requirements have been met.
Excel Engineering
Development of the Peak Flow Statistics
The peak flow statistics are developed directly from the binary output file produced by the SWMM
program. The site is modeled for the Pre-Development, and Post-Development-Mitigated conditions. For
each of these files a specific time period differentiating distinct storms is chosen. The SWMM results are
extracted and each flow value is queried. The majority of the values for Southern California sites are zero
flow. As each successive record is read, as soon as a non-zero value is read the time and flow value of
that record are recorded as the beginning of an event. The first record is automatically recorded as the
“tentative” peak value. As each successive non-zero value is read and the successive flow value is
compared to the peak value and the greater value is retained as the peak value of the storm. As soon as
a successive number of zero values equal to the chosen storm separation value (generally assumed to
be 24 hours), then the time value of the last non-zero value is recorded as the end of the storm, the
duration of the storm is the difference between the end time and the start time, and the peak value is
recorded as the highest flow value between the start and end times.
Once the entire SWMM output file is read all of the distinct storm events will have been recorded in a
special list. The storms will be in the order of their occurrence. To develop the peak flow statistics table
the first step is to sort the storms in descending order of the peak flow value. Once the list is sorted then
the relative rank of each storm is assigned with the highest ranking storm being the storm with the highest
peak flow. There are several methods that can be used to determine which storm should be ranked
above another equally valued storm. For the purposes of these studies an Ordinal ranking is used so that
each storm has a unique rank number. Where two or more storms have equal flow values, the earlier
storm is assigned the higher rank. This is done consistently throughout the storm record. Since we are
only looking at peak flow statistics, it is assumed that the relative ranking of individual (but equal) storms
is irrelevant to the calculations.
The exceedance frequency and return period are both computed using the Weibull formula for plotting
position. Therefore, for a specific event the exceedance frequency F and the return period in years T are
calculated using the following equations1:
F=m/(nR+1) and T=n+1/m
where m is the event’s rank, nR is the total number of events and n is the number of years under analysis.
Once the Peak flow statistics table is complete, a plot of Return Frequency vs. peak flow is created. All
three conditions (pre, post and mitigated) are plotted on the same plot.
1 Pg 169-170 Storm Water Management Model Applications Manual, EPA/600/R-09/000 July 2009
Excel Engineering
The Peak Flow Statistics Analysis
The Peak Flow Statistics analysis is composed of the following series of files:
1. The Peak Flow Frequency Plot
2. The Comparison of the Post-Development Conditions Curve to the Pre-Development Curve
(Pass/Fail)
3. The Peak Flow Statistics Calculations for the Pre-Development Curve.
4. The Peak Flow Statistics Calculations for the Post-Development Curve.
The Peak Flow Frequency Plot
The Peak Flow Frequency Curves are the plotting of both the pre-development and post-development
sets of return period vs peak flow data point pair lists. In addition to these curves horizontal lines are
plotted corresponding to the Q10, Q5, Q2 and Qlf (low flow threshold) values. Within the geomorphically
significant range (Q10 – Qlf) one can see a visual representation of the relative positions of the peak flow
curves. The peak flow curves are compared in a North/South (vertical) direction to compare post
development peak flows to pre-development flows. The Pre-Development curve is plotted in blue, and
the Post-Development curve is plotted in green. As long as the post development curve lies below the
pre-development curve (mostly2), the project meets the peak flow hydromodification requirements.
Pass/Fail comparison of the curves
The next two sets of data are the point by point comparison of the post-development curve and the pre-
development curve. The Pass/Fail table is helpful in determining compliance since the plotted lines can
be difficult to see at the scales suitable for use in a report. Each point on the post- development curve
has a corresponding “X” value (Recurrence Interval), and “Y” value (Peak Flow). For each point on the
post development curve, the “X” value is used to interpolate the corresponding peak flow value from the
pre-development curve. Then the Post-development peak flow value is compared to the Pre-
Development peak flow value. Based on the relative values of each point, pass/fail criteria are
determined point by point.
For each set of data, the upper right hand header value shows the name of the file being displayed (ex.
peakFlowPassFailMitigated.TXT). The first line of the file also shows this value. The next line shows the
time stamp of the file that is being analyzed. The time stamps of all of the report files should be within a
minute or two of each other, otherwise there may have been confusion with the relative files. Each report
run creates and prints all of the files and reports at one time so all the time stamps should be very close.
2 See hydromodification limits for exceedance of pre-development values
Excel Engineering
It should be noted that the SWMM.out files will not have related time stamps since each file is developed
independently.
The first column is the zero based number of the point. The next two columns show the post
development “X” and “Y” values. The next column shows the value interpolated between the two
bounding points on the pre-development curve. The next three columns show the true or false values of
the comparison of the two “Y” values. The last column shows the resultant pass or fail status of the point.
There are three ways a point can pass. They are:
1. Point is outside of the geomorphically significant range Q10 – Qlf
2. Qpost being less than Q pre
3. Qpost being less than 110% of the value of Qpre if the point is between Q5 and Q103
There are four ways that a point can fail. They are:
1. Qpost being greater than Qpre if the point is between Qlf and Q5
2. Qpost being greater than 110% of Qpre if the point is between Qlf and Q10
3. If more than 10% of the points are between 100% and 110% of Qpre for the points between Q5
and Q10
4. If the frequency interval for points > 100% of Qpre is greater than 1 year for the points between Q5
and Q10
A quick scan down the last column will quickly tell if there are any points that fail.
At the bottom of each set of data are the date stamp of the report to the left, and to the right is the page
number/number of pages for the specific set of data (not the pages of the report!). Each new set of data
has its own page numbering. Between the file name in the header row and the page numbering in the
footer row, the engineer can readily scan the document for the data of interest.
The Peak Flow Statistics Calculations
There are two sets of data for the Peak Flow Statistics calculations (Pre-Development and Post-
Development). As was the case for the pass/fail data, the upper right hand corner of each sheet has the
file name. The first row of the data is the SWMM file name. The second row is the SWMM file time
stamp of the file being analyzed. The 4th, 5th, and 6th rows are the calculated values for Q10, Q5, and Q2.
These values are derived by linear interpolation between the nearest bounding points in the listing. While
the relationship between the points in the peak flow analysis is not technically a linear relationship, the
error introduced in using linear interpolation between such relatively close data points is assumed to be
irrelevant. Finally, the footer row shows the report time and the page/number of pages of the data set.
3 See section on how a point can fail point number 3 hereon
Excel Engineering
As was previously discussed, each storm listed was determined by reading the flow values directly from
the binary output file from the SWMM program. The storms were then sorted in descending order of peak
flow values. Then each storm was assigned a unique rank, then the Frequency and Return Period were
calculated using Weibull formulas. Every discharge value for the entire rainfall record is listed in each of
these lists. It should be noted that the derivation of these peak flow statistics values use full precision (i.e.
no rounding off) of the SWMM output values. Since the precision of the calculations may not be the same
as the SWMM program uses, and also the assignment of rank to values of equal peak flow value may
differ slightly from the way SWMM calculates the tables, minor variances in the data values and/or the
order of storms can be expected.
Finally, as was previously stated, the values of the Return Period were plotted vs. the peak flow values to
develop the peak flow frequency curves.
Excel Engineering
~ ~
~,__----~------------~------------I~ ~
Excel Engineering
peakFlowPassFailMitigated.TXT
Compared to:
pre-development SWMM file: V:\22\22081\Engineering\GPIP\Storm\Working Files\Hydmod\Current\22-081 PRE-DEV.out
pre-development time stamp: 5/15/2023 1:39:32 PM
Compare Post-Development Curve to Pre-Development Curve
Flow Control Upper Limit: 1.5627 (cfs)
Flow Control Lower Limit: 0.09940 (cfs)
post-development SWMM file: V:\22\22081\Engineering\GPIP\Storm\Working Files\Hydmod\Current\22081 POST-PC1 - Copy.out
post-development time stamp: 6/3/2025 6:29:35 PMPost PT #Rtn Prd (yrs)Post Dev Q (cfs)Pre Dev Q (cfs)Qpost < QpreQpost > QpreQpost > 110% QprePass/Fail0 58.00 1.50 2.31 TRUE FALSE FALSE Pass- Qpost < Qpre
1 29.00 1.21 1.95 TRUE FALSE FALSE Pass- Qpost < Qpre
2 19.33 1.17 1.84 TRUE FALSE FALSE Pass- Qpost < Qpre
3 14.50 1.13 1.82 TRUE FALSE FALSE Pass- Qpost < Qpre
4 11.60 0.98 1.71 TRUE FALSE FALSE Pass- Qpost < Qpre
5 9.67 0.91 1.53 TRUE FALSE FALSE Pass- Qpost < Qpre
6 8.29 0.83 1.45 TRUE FALSE FALSE Pass- Qpost < Qpre
7 7.25 0.78 1.39 TRUE FALSE FALSE Pass- Qpost < Qpre
8 6.44 0.77 1.37 TRUE FALSE FALSE Pass- Qpost < Qpre
9 5.80 0.66 1.28 TRUE FALSE FALSE Pass- Qpost < Qpre
10 5.27 0.66 1.27 TRUE FALSE FALSE Pass- Qpost < Qpre
11 4.83 0.63 1.25 TRUE FALSE FALSE Pass- Qpost < Qpre
12 4.46 0.61 1.25 TRUE FALSE FALSE Pass- Qpost < Qpre
13 4.14 0.59 1.23 TRUE FALSE FALSE Pass- Qpost < Qpre
14 3.87 0.48 1.20 TRUE FALSE FALSE Pass- Qpost < Qpre
15 3.63 0.45 1.19 TRUE FALSE FALSE Pass- Qpost < Qpre
16 3.41 0.44 1.18 TRUE FALSE FALSE Pass- Qpost < Qpre
17 3.22 0.44 1.18 TRUE FALSE FALSE Pass- Qpost < Qpre
18 3.05 0.44 1.18 TRUE FALSE FALSE Pass- Qpost < Qpre
19 2.90 0.43 1.15 TRUE FALSE FALSE Pass- Qpost < Qpre
20 2.76 0.42 1.08 TRUE FALSE FALSE Pass- Qpost < Qpre
21 2.64 0.41 1.08 TRUE FALSE FALSE Pass- Qpost < Qpre
22 2.52 0.40 1.07 TRUE FALSE FALSE Pass- Qpost < Qpre
23 2.42 0.37 1.07 TRUE FALSE FALSE Pass- Qpost < Qpre
24 2.32 0.36 1.06 TRUE FALSE FALSE Pass- Qpost < Qpre
25 2.23 0.35 1.04 TRUE FALSE FALSE Pass- Qpost < Qpre
26 2.15 0.34 1.03 TRUE FALSE FALSE Pass- Qpost < Qpre
27 2.07 0.33 1.00 TRUE FALSE FALSE Pass- Qpost < Qpre
1/156/4/2025 11:02 AM
Excel Engineering
peakFlowPassFailMitigated.TXTPost PT #Rtn Prd (yrs)Post Dev Q (cfs)Pre Dev Q (cfs)Qpost < QpreQpost > QpreQpost > 110% QprePass/Fail28 2.00 0.30 0.99 TRUE FALSE FALSE Pass- Qpost < Qpre
29 1.93 0.29 0.99 TRUE FALSE FALSE Pass- Qpost < Qpre
30 1.87 0.28 0.93 TRUE FALSE FALSE Pass- Qpost < Qpre
31 1.81 0.25 0.91 TRUE FALSE FALSE Pass- Qpost < Qpre
32 1.76 0.25 0.90 TRUE FALSE FALSE Pass- Qpost < Qpre
33 1.71 0.24 0.87 TRUE FALSE FALSE Pass- Qpost < Qpre
34 1.66 0.24 0.84 TRUE FALSE FALSE Pass- Qpost < Qpre
35 1.61 0.24 0.83 TRUE FALSE FALSE Pass- Qpost < Qpre
36 1.57 0.24 0.82 TRUE FALSE FALSE Pass- Qpost < Qpre
37 1.53 0.22 0.81 TRUE FALSE FALSE Pass- Qpost < Qpre
38 1.49 0.22 0.81 TRUE FALSE FALSE Pass- Qpost < Qpre
39 1.45 0.19 0.79 TRUE FALSE FALSE Pass- Qpost < Qpre
40 1.42 0.17 0.77 TRUE FALSE FALSE Pass- Qpost < Qpre
41 1.38 0.17 0.76 TRUE FALSE FALSE Pass- Qpost < Qpre
42 1.35 0.17 0.75 TRUE FALSE FALSE Pass- Qpost < Qpre
43 1.32 0.16 0.75 TRUE FALSE FALSE Pass- Qpost < Qpre
44 1.29 0.15 0.73 TRUE FALSE FALSE Pass- Qpost < Qpre
45 1.26 0.15 0.72 TRUE FALSE FALSE Pass- Qpost < Qpre
46 1.23 0.13 0.71 TRUE FALSE FALSE Pass- Qpost < Qpre
47 1.21 0.12 0.71 TRUE FALSE FALSE Pass- Qpost < Qpre
48 1.18 0.12 0.69 TRUE FALSE FALSE Pass- Qpost < Qpre
49 1.16 0.12 0.69 TRUE FALSE FALSE Pass- Qpost < Qpre
50 1.14 0.12 0.68 TRUE FALSE FALSE Pass- Qpost < Qpre
51 1.12 0.12 0.66 TRUE FALSE FALSE Pass- Qpost < Qpre
52 1.09 0.12 0.66 TRUE FALSE FALSE Pass- Qpost < Qpre
53 1.07 0.11 0.65 TRUE FALSE FALSE Pass- Qpost < Qpre
54 1.06 0.11 0.65 TRUE FALSE FALSE Pass- Qpost < Qpre
55 1.04 0.11 0.65 TRUE FALSE FALSE Pass- Qpost < Qpre
56 1.02 0.11 0.65 TRUE FALSE FALSE Pass- Qpost < Qpre
57 1.00 0.10 0.64 TRUE FALSE FALSE Pass- Qpost < Qpre
58 0.98 0.10 0.64 TRUE FALSE FALSE Pass- Qpost < Qpre
59 0.97 0.10 0.64 TRUE FALSE FALSE Pass- Qpost < Qpre
60 0.95 0.10 0.63 TRUE FALSE FALSE Pass- Qpost < Qpre
61 0.94 0.10 0.62 TRUE FALSE FALSE Pass- Qpost < Qpre
62 0.92 0.10 0.62 TRUE FALSE FALSE Pass- Qpost < Qpre
63 0.91 0.10 0.61 TRUE FALSE FALSE Pass- Qpost < Qpre
64 0.89 0.10 0.61 TRUE FALSE FALSE Pass- Qpost < Qpre
65 0.88 0.10 0.60 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
2/156/4/2025 11:02 AM
Excel Engineering
peakFlowPassFailMitigated.TXTPost PT #Rtn Prd (yrs)Post Dev Q (cfs)Pre Dev Q (cfs)Qpost < QpreQpost > QpreQpost > 110% QprePass/Fail66 0.87 0.09 0.59 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
67 0.85 0.09 0.59 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
68 0.84 0.09 0.59 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
69 0.83 0.09 0.58 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
70 0.82 0.09 0.58 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
71 0.81 0.09 0.58 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
72 0.80 0.09 0.57 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
73 0.78 0.09 0.56 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
74 0.77 0.09 0.56 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
75 0.76 0.09 0.55 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
76 0.75 0.09 0.55 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
77 0.74 0.09 0.55 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
78 0.73 0.08 0.54 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
79 0.73 0.08 0.53 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
80 0.72 0.08 0.53 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
81 0.71 0.08 0.52 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
82 0.70 0.08 0.52 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
83 0.69 0.08 0.52 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
84 0.68 0.08 0.51 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
85 0.67 0.08 0.51 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
86 0.67 0.08 0.50 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
87 0.66 0.08 0.50 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
88 0.65 0.08 0.50 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
89 0.64 0.08 0.50 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
90 0.64 0.08 0.50 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
91 0.63 0.08 0.48 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
92 0.62 0.08 0.48 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
93 0.62 0.08 0.48 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
94 0.61 0.08 0.47 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
95 0.60 0.08 0.46 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
96 0.60 0.08 0.46 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
97 0.59 0.08 0.45 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
98 0.59 0.08 0.45 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
99 0.58 0.08 0.44 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
100 0.57 0.08 0.44 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
101 0.57 0.08 0.44 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
102 0.56 0.08 0.43 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
103 0.56 0.08 0.43 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
3/156/4/2025 11:02 AM
Excel Engineering
peakFlowPassFailMitigated.TXTPost PT #Rtn Prd (yrs)Post Dev Q (cfs)Pre Dev Q (cfs)Qpost < QpreQpost > QpreQpost > 110% QprePass/Fail104 0.55 0.08 0.43 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
105 0.55 0.08 0.42 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
106 0.54 0.07 0.42 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
107 0.54 0.07 0.42 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
108 0.53 0.07 0.42 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
109 0.53 0.07 0.41 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
110 0.52 0.07 0.41 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
111 0.52 0.07 0.41 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
112 0.51 0.07 0.41 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
113 0.51 0.07 0.40 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
114 0.50 0.07 0.40 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
115 0.50 0.07 0.39 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
116 0.50 0.07 0.38 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
117 0.49 0.07 0.38 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
118 0.49 0.07 0.38 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
119 0.48 0.07 0.38 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
120 0.48 0.07 0.37 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
121 0.48 0.07 0.37 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
122 0.47 0.07 0.37 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
123 0.47 0.07 0.37 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
124 0.46 0.07 0.36 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
125 0.46 0.07 0.36 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
126 0.46 0.07 0.36 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
127 0.45 0.07 0.35 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
128 0.45 0.07 0.35 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
129 0.45 0.07 0.35 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
130 0.44 0.07 0.34 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
131 0.44 0.07 0.34 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
132 0.44 0.07 0.34 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
133 0.43 0.07 0.33 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
134 0.43 0.07 0.33 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
135 0.43 0.07 0.33 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
136 0.42 0.07 0.33 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
137 0.42 0.07 0.33 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
138 0.42 0.06 0.32 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
139 0.41 0.06 0.32 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
140 0.41 0.06 0.32 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
141 0.41 0.06 0.32 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
4/156/4/2025 11:02 AM
Excel Engineering
peakFlowPassFailMitigated.TXTPost PT #Rtn Prd (yrs)Post Dev Q (cfs)Pre Dev Q (cfs)Qpost < QpreQpost > QpreQpost > 110% QprePass/Fail142 0.41 0.06 0.32 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
143 0.40 0.06 0.31 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
144 0.40 0.06 0.30 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
145 0.40 0.06 0.30 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
146 0.40 0.06 0.30 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
147 0.39 0.06 0.29 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
148 0.39 0.06 0.28 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
149 0.39 0.06 0.28 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
150 0.38 0.06 0.27 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
151 0.38 0.06 0.25 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
152 0.38 0.06 0.25 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
153 0.38 0.06 0.25 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
154 0.37 0.06 0.25 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
155 0.37 0.06 0.25 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
156 0.37 0.06 0.24 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
157 0.37 0.06 0.24 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
158 0.37 0.06 0.24 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
159 0.36 0.06 0.24 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
160 0.36 0.06 0.23 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
161 0.36 0.06 0.23 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
162 0.36 0.06 0.23 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
163 0.35 0.06 0.22 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
164 0.35 0.06 0.22 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
165 0.35 0.06 0.22 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
166 0.35 0.06 0.21 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
167 0.35 0.06 0.21 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
168 0.34 0.06 0.21 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
169 0.34 0.06 0.20 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
170 0.34 0.06 0.19 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
171 0.34 0.06 0.18 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
172 0.34 0.06 0.18 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
173 0.33 0.06 0.18 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
174 0.33 0.06 0.18 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
175 0.33 0.06 0.17 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
176 0.33 0.06 0.17 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
177 0.33 0.06 0.17 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
178 0.32 0.06 0.17 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
179 0.32 0.06 0.16 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
5/156/4/2025 11:02 AM
Excel Engineering
peakFlowPassFailMitigated.TXTPost PT #Rtn Prd (yrs)Post Dev Q (cfs)Pre Dev Q (cfs)Qpost < QpreQpost > QpreQpost > 110% QprePass/Fail180 0.32 0.06 0.15 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
181 0.32 0.06 0.15 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
182 0.32 0.06 0.14 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
183 0.32 0.05 0.14 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
184 0.31 0.05 0.14 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
185 0.31 0.05 0.13 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
186 0.31 0.05 0.12 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
187 0.31 0.05 0.12 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
188 0.31 0.05 0.11 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
189 0.31 0.05 0.10 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
190 0.30 0.05 0.09 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
191 0.30 0.05 0.08 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
192 0.30 0.05 0.07 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
193 0.30 0.05 0.07 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
194 0.30 0.05 0.06 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
195 0.30 0.05 0.06 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
196 0.29 0.05 0.06 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
197 0.29 0.05 0.06 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
198 0.29 0.05 0.05 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
199 0.29 0.05 0.05 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
200 0.29 0.05 0.05 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
201 0.29 0.05 0.05 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
202 0.29 0.05 0.04 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
203 0.28 0.05 0.04 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
204 0.28 0.05 0.04 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
205 0.28 0.05 0.04 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
206 0.28 0.05 0.03 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
207 0.28 0.05 0.01 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
208 0.28 0.05 0.01 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
209 0.28 0.05 0.01 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
210 0.28 0.05 0.01 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
211 0.27 0.05 0.01 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
212 0.27 0.05 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
213 0.27 0.05 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
214 0.27 0.05 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
215 0.27 0.05 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
216 0.27 0.05 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
217 0.27 0.05 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
6/156/4/2025 11:02 AM
Excel Engineering
peakFlowPassFailMitigated.TXTPost PT #Rtn Prd (yrs)Post Dev Q (cfs)Pre Dev Q (cfs)Qpost < QpreQpost > QpreQpost > 110% QprePass/Fail218 0.27 0.05 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
219 0.26 0.05 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
220 0.26 0.05 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
221 0.26 0.05 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
222 0.26 0.05 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
223 0.26 0.05 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
224 0.26 0.05 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
225 0.26 0.05 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
226 0.26 0.05 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
227 0.25 0.05 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
228 0.25 0.05 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
229 0.25 0.05 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
230 0.25 0.05 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
231 0.25 0.05 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
232 0.25 0.05 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
233 0.25 0.05 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
234 0.25 0.05 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
235 0.25 0.05 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
236 0.25 0.05 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
237 0.24 0.05 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
238 0.24 0.05 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
239 0.24 0.05 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
240 0.24 0.05 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
241 0.24 0.05 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
242 0.24 0.05 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
243 0.24 0.05 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
244 0.24 0.05 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
245 0.24 0.05 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
246 0.24 0.05 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
247 0.23 0.05 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
248 0.23 0.05 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
249 0.23 0.05 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
250 0.23 0.05 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
251 0.23 0.05 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
252 0.23 0.05 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
253 0.23 0.05 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
254 0.23 0.05 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
255 0.23 0.05 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
7/156/4/2025 11:02 AM
Excel Engineering
peakFlowPassFailMitigated.TXTPost PT #Rtn Prd (yrs)Post Dev Q (cfs)Pre Dev Q (cfs)Qpost < QpreQpost > QpreQpost > 110% QprePass/Fail256 0.23 0.05 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
257 0.22 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
258 0.22 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
259 0.22 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
260 0.22 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
261 0.22 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
262 0.22 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
263 0.22 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
264 0.22 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
265 0.22 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
266 0.22 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
267 0.21 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
268 0.21 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
269 0.21 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
270 0.21 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
271 0.21 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
272 0.21 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
273 0.21 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
274 0.21 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
275 0.21 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
276 0.21 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
277 0.21 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
278 0.21 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
279 0.20 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
280 0.20 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
281 0.20 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
282 0.20 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
283 0.20 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
284 0.20 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
285 0.20 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
286 0.20 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
287 0.20 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
288 0.20 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
289 0.20 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
290 0.20 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
291 0.20 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
292 0.20 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
293 0.19 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
8/156/4/2025 11:02 AM
Excel Engineering
peakFlowPassFailMitigated.TXTPost PT #Rtn Prd (yrs)Post Dev Q (cfs)Pre Dev Q (cfs)Qpost < QpreQpost > QpreQpost > 110% QprePass/Fail294 0.19 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
295 0.19 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
296 0.19 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
297 0.19 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
298 0.19 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
299 0.19 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
300 0.19 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
301 0.19 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
302 0.19 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
303 0.19 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
304 0.19 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
305 0.19 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
306 0.18 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
307 0.18 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
308 0.18 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
309 0.18 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
310 0.18 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
311 0.18 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
312 0.18 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
313 0.18 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
314 0.18 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
315 0.18 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
316 0.18 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
317 0.18 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
318 0.18 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
319 0.18 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
320 0.18 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
321 0.17 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
322 0.17 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
323 0.17 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
324 0.17 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
325 0.17 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
326 0.17 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
327 0.17 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
328 0.17 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
329 0.17 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
330 0.17 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
331 0.17 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
9/156/4/2025 11:02 AM
Excel Engineering
peakFlowPassFailMitigated.TXTPost PT #Rtn Prd (yrs)Post Dev Q (cfs)Pre Dev Q (cfs)Qpost < QpreQpost > QpreQpost > 110% QprePass/Fail332 0.17 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
333 0.17 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
334 0.17 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
335 0.17 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
336 0.17 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
337 0.16 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
338 0.16 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
339 0.16 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
340 0.16 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
341 0.16 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
342 0.16 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
343 0.16 0.04 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
344 0.16 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
345 0.16 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
346 0.16 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
347 0.16 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
348 0.16 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
349 0.16 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
350 0.16 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
351 0.16 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
352 0.16 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
353 0.16 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
354 0.16 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
355 0.16 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
356 0.15 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
357 0.15 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
358 0.15 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
359 0.15 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
360 0.15 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
361 0.15 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
362 0.15 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
363 0.15 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
364 0.15 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
365 0.15 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
366 0.15 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
367 0.15 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
368 0.15 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
369 0.15 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
10/156/4/2025 11:02 AM
Excel Engineering
peakFlowPassFailMitigated.TXTPost PT #Rtn Prd (yrs)Post Dev Q (cfs)Pre Dev Q (cfs)Qpost < QpreQpost > QpreQpost > 110% QprePass/Fail370 0.15 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
371 0.15 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
372 0.15 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
373 0.15 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
374 0.15 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
375 0.15 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
376 0.14 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
377 0.14 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
378 0.14 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
379 0.14 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
380 0.14 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
381 0.14 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
382 0.14 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
383 0.14 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
384 0.14 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
385 0.14 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
386 0.14 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
387 0.14 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
388 0.14 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
389 0.14 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
390 0.14 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
391 0.14 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
392 0.14 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
393 0.14 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
394 0.14 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
395 0.13 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
396 0.13 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
397 0.13 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
398 0.13 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
399 0.13 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
400 0.13 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
401 0.13 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
402 0.13 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
403 0.13 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
404 0.13 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
405 0.13 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
406 0.13 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
407 0.13 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
11/156/4/2025 11:02 AM
Excel Engineering
peakFlowPassFailMitigated.TXTPost PT #Rtn Prd (yrs)Post Dev Q (cfs)Pre Dev Q (cfs)Qpost < QpreQpost > QpreQpost > 110% QprePass/Fail408 0.13 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
409 0.13 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
410 0.13 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
411 0.13 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
412 0.13 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
413 0.13 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
414 0.13 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
415 0.13 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
416 0.13 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
417 0.13 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
418 0.12 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
419 0.12 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
420 0.12 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
421 0.12 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
422 0.12 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
423 0.12 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
424 0.12 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
425 0.12 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
426 0.12 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
427 0.12 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
428 0.12 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
429 0.12 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
430 0.12 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
431 0.12 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
432 0.12 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
433 0.12 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
434 0.12 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
435 0.12 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
436 0.12 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
437 0.12 0.03 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
438 0.12 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
439 0.12 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
440 0.12 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
441 0.12 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
442 0.12 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
443 0.12 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
444 0.12 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
445 0.12 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
12/156/4/2025 11:02 AM
Excel Engineering
peakFlowPassFailMitigated.TXTPost PT #Rtn Prd (yrs)Post Dev Q (cfs)Pre Dev Q (cfs)Qpost < QpreQpost > QpreQpost > 110% QprePass/Fail446 0.12 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
447 0.11 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
448 0.11 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
449 0.11 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
450 0.11 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
451 0.11 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
452 0.11 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
453 0.11 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
454 0.11 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
455 0.11 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
456 0.11 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
457 0.11 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
458 0.11 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
459 0.11 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
460 0.11 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
461 0.11 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
462 0.11 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
463 0.11 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
464 0.11 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
465 0.11 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
466 0.11 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
467 0.11 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
468 0.11 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
469 0.11 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
470 0.11 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
471 0.11 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
472 0.11 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
473 0.11 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
474 0.11 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
475 0.11 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
476 0.11 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
477 0.11 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
478 0.11 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
479 0.10 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
480 0.10 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
481 0.10 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
482 0.10 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
483 0.10 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
13/156/4/2025 11:02 AM
Excel Engineering
peakFlowPassFailMitigated.TXTPost PT #Rtn Prd (yrs)Post Dev Q (cfs)Pre Dev Q (cfs)Qpost < QpreQpost > QpreQpost > 110% QprePass/Fail484 0.10 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
485 0.10 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
486 0.10 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
487 0.10 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
488 0.10 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
489 0.10 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
490 0.10 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
491 0.10 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
492 0.10 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
493 0.10 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
494 0.10 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
495 0.10 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
496 0.10 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
497 0.10 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
498 0.10 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
499 0.10 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
500 0.10 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
501 0.10 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
502 0.10 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
503 0.10 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
504 0.10 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
505 0.10 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
506 0.10 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
507 0.10 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
508 0.10 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
509 0.10 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
510 0.10 0.02 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
511 0.10 0.01 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
512 0.10 0.01 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
513 0.10 0.01 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
514 0.10 0.01 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
515 0.10 0.01 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
516 0.10 0.01 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
517 0.10 0.01 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
518 0.10 0.01 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
519 0.09 0.01 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
520 0.09 0.01 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
521 0.09 0.01 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
14/156/4/2025 11:02 AM
Excel Engineering
peakFlowPassFailMitigated.TXTPost PT #Rtn Prd (yrs)Post Dev Q (cfs)Pre Dev Q (cfs)Qpost < QpreQpost > QpreQpost > 110% QprePass/Fail522 0.09 0.01 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
523 0.09 0.01 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
524 0.09 0.01 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
525 0.09 0.01 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
526 0.09 0.01 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
527 0.09 0.01 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
528 0.09 0.01 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
529 0.09 0.01 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
530 0.09 0.01 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
531 0.09 0.01 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
532 0.09 0.01 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
533 0.09 0.01 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
534 0.09 0.01 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
535 0.09 0.01 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
536 0.09 0.01 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
537 0.09 0.01 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
538 0.09 0.01 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
539 0.09 0.01 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
540 0.09 0.01 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
541 0.09 0.01 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
542 0.09 0.01 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
543 0.09 0.01 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
544 0.09 0.01 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
545 0.09 0.01 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
546 0.09 0.01 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
547 0.09 0.01 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
548 0.09 0.01 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
549 0.09 0.01 0.00 FALSE FALSE FALSE Pass- Qpost Below Qlf (0.09940 (cfs))
15/156/4/2025 11:02 AM
Excel Engineering
peakFlowStatisticsPre.csv
Rank Start Date End Date Duration (hr) Peak (cfs) Frequency (%) Return Period (Yr)
1 2003/04/14 13:00:00 2003/04/14 20:00:00 8 2.308 0.48% 58
2 1978/01/04 15:00:00 1978/01/04 16:00:00 2 1.953 0.95% 29
3 1983/10/01 01:00:00 1983/10/01 02:00:00 2 1.839 1.43% 19.33
4 1995/01/04 16:00:00 1995/01/04 21:00:00 6 1.824 1.90% 14.5
5 1979/01/15 13:00:00 1979/01/15 14:00:00 2 1.714 2.38% 11.6
6 2003/02/25 15:00:00 2003/02/25 19:00:00 5 1.531 2.86% 9.67
7 1986/09/23 23:00:00 1986/09/23 23:00:00 1 1.449 3.33% 8.29
8 1969/02/25 14:00:00 1969/02/25 19:00:00 6 1.386 3.81% 7.25
9 1958/02/04 03:00:00 1958/02/04 04:00:00 2 1.372 4.29% 6.44
10 1993/01/13 21:00:00 1993/01/14 04:00:00 8 1.284 4.76%5.8
11 1980/02/20 21:00:00 1980/02/21 06:00:00 10 1.275 5.24% 5.27
12 2000/10/29 22:00:00 2000/10/29 23:00:00 2 1.254 5.71%4.83
13 2005/02/18 21:00:00 2005/02/18 22:00:00 2 1.248 6.19%4.46
14 1958/04/01 15:00:00 1958/04/01 18:00:00 4 1.233 6.67%4.14
15 2004/10/27 04:00:00 2004/10/27 07:00:00 4 1.197 7.14%3.87
16 1952/01/16 12:00:00 1952/01/16 14:00:00 3 1.193 7.62%3.63
17 1970/12/19 02:00:00 1970/12/19 04:00:00 3 1.183 8.10%3.41
18 1982/03/17 11:00:00 1982/03/17 20:00:00 10 1.182 8.57% 3.22
19 1952/11/15 13:00:00 1952/11/15 14:00:00 2 1.181 9.05%3.05
20 1978/03/01 03:00:00 1978/03/01 07:00:00 5 1.147 9.52%2.9
21 2008/01/27 00:00:00 2008/01/27 20:00:00 21 1.077 10.00% 2.76
22 1998/02/03 16:00:00 1998/02/03 18:00:00 3 1.077 10.48% 2.64
23 2004/10/20 09:00:00 2004/10/20 14:00:00 6 1.07 10.95%2.52
24 1978/02/10 02:00:00 1978/02/10 05:00:00 4 1.066 11.43% 2.42
25 1965/11/22 14:00:00 1965/11/23 03:00:00 14 1.056 11.90% 2.32
26 1983/01/29 00:00:00 1983/01/29 01:00:00 2 1.039 12.38% 2.23
27 1983/02/27 16:00:00 1983/02/27 16:00:00 1 1.03 12.86%2.15
28 1991/12/29 16:00:00 1991/12/30 00:00:00 9 0.998 13.33% 2.07
29 1998/02/22 17:00:00 1998/02/23 18:00:00 26 0.994 13.81% 2
30 1980/02/16 18:00:00 1980/02/16 19:00:00 2 0.986 14.29% 1.93
31 1998/02/17 17:00:00 1998/02/17 18:00:00 2 0.932 14.76% 1.87
32 1993/01/18 09:00:00 1993/01/18 14:00:00 6 0.908 15.24% 1.81
33 2008/01/06 23:00:00 2008/01/07 00:00:00 2 0.895 15.71% 1.76
34 1980/03/02 21:00:00 1980/03/02 21:00:00 1 0.875 16.19% 1.71
Peak Flow Statistics Table Values
SWMM.out file name: V:\22\22081\Engineering\GPIP\Storm\Working Files\Hydmod\Current\22-081 PRE-DEV.out
SWMM.out time stamp: 5/15/2023 1:39:32 PM
Q10: 1.563 (cfs)
Q5: 1.262 (cfs)
Q2: 0.994 (cfs)
1/66/4/2025 11:02 AM
Excel Engineering
peakFlowStatisticsPre.csv
Rank Start Date End Date Duration (hr) Peak (cfs) Frequency (%) Return Period (Yr)
35 1978/01/16 19:00:00 1978/01/16 23:00:00 5 0.843 16.67% 1.66
36 1995/03/11 03:00:00 1995/03/11 22:00:00 20 0.827 17.14% 1.61
37 1994/02/04 09:00:00 1994/02/04 09:00:00 1 0.821 17.62% 1.57
38 1961/12/02 08:00:00 1961/12/02 08:00:00 1 0.811 18.10% 1.53
39 1998/02/14 17:00:00 1998/02/14 18:00:00 2 0.808 18.57% 1.49
40 1986/03/15 22:00:00 1986/03/15 22:00:00 1 0.791 19.05% 1.45
41 1986/02/15 00:00:00 1986/02/15 05:00:00 6 0.768 19.52% 1.42
42 1985/11/11 09:00:00 1985/11/11 09:00:00 1 0.762 20.00% 1.38
43 1991/02/27 18:00:00 1991/03/01 10:00:00 41 0.748 20.48% 1.35
44 1980/01/28 22:00:00 1980/01/29 05:00:00 8 0.748 20.95% 1.32
45 2002/11/08 17:00:00 2002/11/08 17:00:00 1 0.726 21.43% 1.29
46 2003/02/11 17:00:00 2003/02/12 17:00:00 25 0.725 21.90% 1.26
47 1969/02/06 09:00:00 1969/02/06 14:00:00 6 0.713 22.38% 1.23
48 1993/02/18 12:00:00 1993/02/18 12:00:00 1 0.712 22.86% 1.21
49 2008/02/22 04:00:00 2008/02/22 08:00:00 5 0.69 23.33%1.18
50 1992/02/12 17:00:00 1992/02/13 06:00:00 14 0.686 23.81% 1.16
51 1952/03/15 20:00:00 1952/03/16 04:00:00 9 0.677 24.29% 1.14
52 1963/09/18 18:00:00 1963/09/18 21:00:00 4 0.665 24.76% 1.12
53 1993/02/08 01:00:00 1993/02/08 10:00:00 10 0.655 25.24% 1.09
54 2005/02/21 03:00:00 2005/02/23 03:00:00 49 0.647 25.71% 1.07
55 2005/01/11 01:00:00 2005/01/11 04:00:00 4 0.647 26.19% 1.06
56 1993/02/19 19:00:00 1993/02/19 20:00:00 2 0.646 26.67% 1.04
57 1980/02/18 04:00:00 1980/02/19 08:00:00 29 0.645 27.14% 1.02
58 2001/02/13 17:00:00 2001/02/14 17:00:00 25 0.641 27.62% 1
59 2003/03/15 17:00:00 2003/03/15 17:00:00 1 0.637 28.10% 0.98
60 1981/03/19 20:00:00 1981/03/19 20:00:00 1 0.635 28.57% 0.97
61 1983/03/01 13:00:00 1983/03/04 03:00:00 63 0.632 29.05% 0.95
62 2004/12/31 14:00:00 2004/12/31 15:00:00 2 0.618 29.52% 0.94
63 1977/12/29 06:00:00 1977/12/29 06:00:00 1 0.615 30.00% 0.92
64 1978/01/14 23:00:00 1978/01/15 03:00:00 5 0.615 30.48% 0.91
65 1991/03/27 02:00:00 1991/03/27 03:00:00 2 0.612 30.95% 0.89
66 1963/03/17 00:00:00 1963/03/17 01:00:00 2 0.597 31.43% 0.88
67 1960/01/12 03:00:00 1960/01/12 07:00:00 5 0.592 31.90% 0.87
68 1981/11/28 03:00:00 1981/11/28 21:00:00 19 0.59 32.38% 0.85
69 1971/12/24 20:00:00 1971/12/24 22:00:00 3 0.586 32.86% 0.84
70 1973/11/22 23:00:00 1973/11/23 00:00:00 2 0.583 33.33% 0.83
71 1988/12/24 22:00:00 1988/12/24 23:00:00 2 0.583 33.81% 0.82
72 2005/01/09 04:00:00 2005/01/09 21:00:00 18 0.579 34.29% 0.81
73 1993/01/15 13:00:00 1993/01/16 21:00:00 33 0.567 34.76% 0.8
74 1965/12/10 08:00:00 1965/12/10 08:00:00 1 0.563 35.24% 0.78
75 1977/08/17 02:00:00 1977/08/17 03:00:00 2 0.56 35.71%0.77
76 1960/04/27 09:00:00 1960/04/27 09:00:00 1 0.551 36.19% 0.76
2/66/4/2025 11:02 AM
Excel Engineering
peakFlowStatisticsPre.csv
Rank Start Date End Date Duration (hr) Peak (cfs) Frequency (%) Return Period (Yr)
77 1980/01/11 00:00:00 1980/01/12 08:00:00 33 0.551 36.67% 0.75
78 1992/02/15 13:00:00 1992/02/15 13:00:00 1 0.55 37.14%0.74
79 1999/01/26 22:00:00 1999/01/26 22:00:00 1 0.544 37.62% 0.73
80 1975/04/08 17:00:00 1975/04/08 21:00:00 5 0.531 38.10% 0.73
81 1997/01/12 16:00:00 1997/01/13 05:00:00 14 0.526 38.57% 0.72
82 1979/01/06 02:00:00 1979/01/06 05:00:00 4 0.52 39.05%0.71
83 1983/01/27 08:00:00 1983/01/27 09:00:00 2 0.519 39.52% 0.7
84 1972/01/16 22:00:00 1972/01/16 22:00:00 1 0.519 40.00% 0.69
85 1983/12/25 05:00:00 1983/12/25 10:00:00 6 0.513 40.48% 0.68
86 1959/12/24 12:00:00 1959/12/24 13:00:00 2 0.512 40.95% 0.67
87 1959/02/11 10:00:00 1959/02/11 11:00:00 2 0.502 41.43% 0.67
88 1966/12/05 02:00:00 1966/12/05 10:00:00 9 0.502 41.90% 0.66
89 1957/01/13 04:00:00 1957/01/13 07:00:00 4 0.496 42.38% 0.65
90 1958/02/19 13:00:00 1958/02/19 13:00:00 1 0.496 42.86% 0.64
91 1968/03/08 08:00:00 1968/03/08 10:00:00 3 0.495 43.33% 0.64
92 1958/03/15 19:00:00 1958/03/16 10:00:00 16 0.482 43.81% 0.63
93 1960/02/29 06:00:00 1960/03/01 05:00:00 24 0.482 44.29% 0.62
94 1995/03/05 07:00:00 1995/03/05 21:00:00 15 0.482 44.76% 0.62
95 1988/11/25 09:00:00 1988/11/25 09:00:00 1 0.466 45.24% 0.61
96 1964/11/17 16:00:00 1964/11/17 17:00:00 2 0.464 45.71% 0.6
97 1972/11/14 14:00:00 1972/11/14 15:00:00 2 0.46 46.19%0.6
98 1966/02/07 23:00:00 1966/02/07 23:00:00 1 0.455 46.67% 0.59
99 1983/11/24 23:00:00 1983/11/24 23:00:00 1 0.447 47.14% 0.59
100 1994/03/24 22:00:00 1994/03/25 00:00:00 3 0.442 47.62% 0.58
101 1972/11/16 12:00:00 1972/11/17 06:00:00 19 0.437 48.10% 0.57
102 1965/11/16 14:00:00 1965/11/16 17:00:00 4 0.437 48.57% 0.57
103 1978/02/12 21:00:00 1978/02/13 23:00:00 27 0.432 49.05% 0.56
104 2005/04/28 08:00:00 2005/04/28 08:00:00 1 0.428 49.52% 0.56
105 1991/03/25 06:00:00 1991/03/25 06:00:00 1 0.427 50.00% 0.55
106 1962/01/20 16:00:00 1962/01/20 18:00:00 3 0.422 50.48% 0.55
107 2002/12/20 17:00:00 2002/12/20 17:00:00 1 0.421 50.95% 0.54
108 2001/02/25 17:00:00 2001/02/26 17:00:00 25 0.416 51.43% 0.54
109 2004/02/26 05:00:00 2004/02/26 08:00:00 4 0.416 51.90% 0.53
110 1956/01/26 20:00:00 1956/01/27 03:00:00 8 0.414 52.38% 0.53
111 1954/01/19 16:00:00 1954/01/19 21:00:00 6 0.412 52.86% 0.52
112 1958/03/21 21:00:00 1958/03/22 05:00:00 9 0.41 53.33% 0.52
113 2005/01/03 08:00:00 2005/01/03 10:00:00 3 0.41 53.81% 0.51
114 1957/02/28 23:00:00 1957/03/01 10:00:00 12 0.405 54.29% 0.51
115 1995/01/12 09:00:00 1995/01/12 13:00:00 5 0.402 54.76% 0.5
116 1960/02/02 00:00:00 1960/02/02 01:00:00 2 0.392 55.24% 0.5
117 1965/04/08 15:00:00 1965/04/09 00:00:00 10 0.384 55.71% 0.5
118 1982/12/22 23:00:00 1982/12/22 23:00:00 1 0.381 56.19% 0.49
3/66/4/2025 11:02 AM
Excel Engineering
peakFlowStatisticsPre.csv
Rank Start Date End Date Duration (hr) Peak (cfs) Frequency (%) Return Period (Yr)
119 1983/04/20 03:00:00 1983/04/20 04:00:00 2 0.376 56.67% 0.49
120 2007/11/30 15:00:00 2007/11/30 20:00:00 6 0.375 57.14% 0.48
121 2005/01/07 19:00:00 2005/01/07 19:00:00 1 0.374 57.62% 0.48
122 1982/01/01 09:00:00 1982/01/01 10:00:00 2 0.373 58.10% 0.48
123 1951/12/29 23:00:00 1951/12/30 08:00:00 10 0.373 58.57% 0.47
124 1976/02/06 04:00:00 1976/02/06 06:00:00 3 0.366 59.05% 0.47
125 1988/12/21 06:00:00 1988/12/21 06:00:00 1 0.36 59.52% 0.46
126 1969/01/24 11:00:00 1969/01/25 15:00:00 29 0.357 60.00% 0.46
127 1960/01/14 18:00:00 1960/01/14 20:00:00 3 0.356 60.48% 0.46
128 1980/01/09 12:00:00 1980/01/09 12:00:00 1 0.354 60.95% 0.45
129 1978/01/10 05:00:00 1978/01/10 05:00:00 1 0.349 61.43% 0.45
130 1988/04/20 09:00:00 1988/04/20 09:00:00 1 0.347 61.90% 0.45
131 1970/12/21 08:00:00 1970/12/21 08:00:00 1 0.342 62.38% 0.44
132 1963/11/20 08:00:00 1963/11/21 04:00:00 21 0.341 62.86% 0.44
133 1998/02/07 17:00:00 1998/02/08 17:00:00 25 0.338 63.33% 0.44
134 1952/12/02 01:00:00 1952/12/02 01:00:00 1 0.334 63.81% 0.43
135 1996/11/22 01:00:00 1996/11/22 02:00:00 2 0.332 64.29% 0.43
136 1958/04/03 10:00:00 1958/04/03 11:00:00 2 0.329 64.76% 0.43
137 1957/01/29 01:00:00 1957/01/29 07:00:00 7 0.327 65.24% 0.42
138 1980/03/06 10:00:00 1980/03/06 10:00:00 1 0.327 65.71% 0.42
139 1986/11/18 04:00:00 1986/11/18 04:00:00 1 0.324 66.19% 0.42
140 1985/11/29 09:00:00 1985/11/29 13:00:00 5 0.323 66.67% 0.41
141 2002/12/16 17:00:00 2002/12/16 17:00:00 1 0.322 67.14% 0.41
142 1981/01/29 18:00:00 1981/01/29 18:00:00 1 0.318 67.62% 0.41
143 1978/09/05 18:00:00 1978/09/05 18:00:00 1 0.317 68.10% 0.41
144 1973/02/13 00:00:00 1973/02/13 02:00:00 3 0.309 68.57% 0.4
145 2007/01/30 23:00:00 2007/01/30 23:00:00 1 0.301 69.05% 0.4
146 1977/01/03 04:00:00 1977/01/03 04:00:00 1 0.299 69.52% 0.4
147 1967/03/13 20:00:00 1967/03/13 21:00:00 2 0.296 70.00% 0.4
148 1952/01/17 22:00:00 1952/01/18 05:00:00 8 0.293 70.48% 0.39
149 2001/12/09 17:00:00 2001/12/09 17:00:00 1 0.281 70.95% 0.39
150 1963/02/10 20:00:00 1963/02/10 20:00:00 1 0.278 71.43% 0.39
151 2000/03/05 17:00:00 2000/03/05 17:00:00 1 0.274 71.90% 0.38
152 2004/12/28 10:00:00 2004/12/29 09:00:00 24 0.254 72.38% 0.38
153 1997/01/15 16:00:00 1997/01/15 17:00:00 2 0.254 72.86% 0.38
154 1987/12/16 19:00:00 1987/12/17 03:00:00 9 0.248 73.33% 0.38
155 1993/01/06 13:00:00 1993/01/06 14:00:00 2 0.247 73.81% 0.37
156 1987/02/25 01:00:00 1987/02/25 01:00:00 1 0.246 74.29% 0.37
157 1997/01/26 01:00:00 1997/01/26 05:00:00 5 0.245 74.76% 0.37
158 1970/11/30 14:00:00 1970/11/30 23:00:00 10 0.241 75.24% 0.37
159 1992/01/07 19:00:00 1992/01/07 22:00:00 4 0.237 75.71% 0.37
160 1967/12/18 17:00:00 1967/12/18 19:00:00 3 0.236 76.19% 0.36
4/66/4/2025 11:02 AM
Excel Engineering
peakFlowStatisticsPre.csv
Rank Start Date End Date Duration (hr) Peak (cfs) Frequency (%) Return Period (Yr)
161 1977/01/06 14:00:00 1977/01/06 21:00:00 8 0.232 76.67% 0.36
162 1966/12/06 19:00:00 1966/12/06 20:00:00 2 0.231 77.14% 0.36
163 1980/02/14 03:00:00 1980/02/15 01:00:00 23 0.226 77.62% 0.36
164 1992/01/05 15:00:00 1992/01/05 22:00:00 8 0.224 78.10% 0.35
165 1958/04/07 04:00:00 1958/04/07 14:00:00 11 0.218 78.57% 0.35
166 1964/01/22 08:00:00 1964/01/22 08:00:00 1 0.217 79.05% 0.35
167 1967/01/22 17:00:00 1967/01/22 23:00:00 7 0.21 79.52% 0.35
168 1969/01/26 18:00:00 1969/01/26 18:00:00 1 0.208 80.00% 0.35
169 1995/01/26 09:00:00 1995/01/26 09:00:00 1 0.206 80.48% 0.34
170 1986/09/25 05:00:00 1986/09/25 05:00:00 1 0.196 80.95% 0.34
171 2006/03/11 07:00:00 2006/03/11 07:00:00 1 0.191 81.43% 0.34
172 1973/03/11 12:00:00 1973/03/11 20:00:00 9 0.181 81.90% 0.34
173 1981/03/02 12:00:00 1981/03/02 12:00:00 1 0.18 82.38% 0.34
174 1952/11/30 02:00:00 1952/11/30 03:00:00 2 0.179 82.86% 0.33
175 1983/03/24 03:00:00 1983/03/24 03:00:00 1 0.178 83.33% 0.33
176 1952/03/07 14:00:00 1952/03/07 17:00:00 4 0.174 83.81% 0.33
177 1956/04/13 12:00:00 1956/04/13 16:00:00 5 0.172 84.29% 0.33
178 1955/01/18 16:00:00 1955/01/18 16:00:00 1 0.171 84.76% 0.33
179 1987/10/12 11:00:00 1987/10/12 12:00:00 2 0.167 85.24% 0.32
180 1957/01/07 15:00:00 1957/01/07 17:00:00 3 0.161 85.71% 0.32
181 1991/03/20 09:00:00 1991/03/20 09:00:00 1 0.147 86.19% 0.32
182 1958/01/26 09:00:00 1958/01/26 09:00:00 1 0.146 86.67% 0.32
183 1986/03/10 08:00:00 1986/03/10 08:00:00 1 0.145 87.14% 0.32
184 1998/05/12 17:00:00 1998/05/12 17:00:00 1 0.141 87.62% 0.32
185 1993/03/28 02:00:00 1993/03/28 03:00:00 2 0.135 88.10% 0.31
186 1957/05/11 02:00:00 1957/05/11 02:00:00 1 0.13 88.57% 0.31
187 1990/02/17 18:00:00 1990/02/17 18:00:00 1 0.12 89.05% 0.31
188 1978/02/08 20:00:00 1978/02/08 20:00:00 1 0.119 89.52% 0.31
189 1969/02/20 04:00:00 1969/02/20 04:00:00 1 0.109 90.00% 0.31
190 1954/02/13 19:00:00 1954/02/13 21:00:00 3 0.101 90.48% 0.31
191 1984/12/27 17:00:00 1984/12/27 17:00:00 1 0.089 90.95% 0.3
192 1983/03/06 05:00:00 1983/03/06 05:00:00 1 0.079 91.43% 0.3
193 1979/03/19 03:00:00 1979/03/19 03:00:00 1 0.071 91.90% 0.3
194 1967/11/30 16:00:00 1967/11/30 16:00:00 1 0.068 92.38% 0.3
195 1995/04/18 10:00:00 1995/04/18 11:00:00 2 0.063 92.86% 0.3
196 1967/01/24 20:00:00 1967/01/24 22:00:00 3 0.062 93.33% 0.3
197 2001/01/11 05:00:00 2001/01/11 05:00:00 1 0.057 93.81% 0.29
198 1990/01/17 01:00:00 1990/01/17 01:00:00 1 0.056 94.29% 0.29
199 2000/02/20 17:00:00 2000/02/21 17:00:00 25 0.054 94.76% 0.29
200 1965/04/03 05:00:00 1965/04/03 05:00:00 1 0.047 95.24% 0.29
201 1978/02/07 17:00:00 1978/02/07 18:00:00 2 0.047 95.71% 0.29
202 1973/02/15 11:00:00 1973/02/15 11:00:00 1 0.045 96.19% 0.29
5/66/4/2025 11:02 AM
Excel Engineering
peakFlowStatisticsPre.csv
Rank Start Date End Date Duration (hr) Peak (cfs) Frequency (%) Return Period (Yr)
203 1957/12/17 05:00:00 1957/12/17 05:00:00 1 0.045 96.67% 0.29
204 1954/03/23 09:00:00 1954/03/23 10:00:00 2 0.042 97.14% 0.28
205 1967/11/21 13:00:00 1967/11/21 13:00:00 1 0.042 97.62% 0.28
206 1995/01/08 03:00:00 1995/01/08 04:00:00 2 0.039 98.10% 0.28
207 1969/02/24 08:00:00 1969/02/24 08:00:00 1 0.03 98.57% 0.28
208 1995/01/10 20:00:00 1995/01/10 20:00:00 1 0.014 99.05% 0.28
209 1997/12/06 17:00:00 1997/12/06 17:00:00 1 0.013 99.52% 0.28
-------------End of Data-----------------
6/66/4/2025 11:02 AM
Excel Engineering
peakFlowStatisticsPostMitigated.csv
Rank Start Date End Date Duration (hr) Peak (cfs) Frequency (%) Return Period (Yr)
1 2003/04/14 07:00:00 2003/04/16 02:00:00 44 1.501 0.15%58
2 1995/01/03 07:00:00 1995/01/06 00:00:00 66 1.209 0.30%29
3 1979/01/14 19:00:00 1979/01/19 06:00:00 108 1.175 0.45% 19.33
4 1983/09/29 23:00:00 1983/10/02 06:00:00 56 1.128 0.60%14.5
5 1978/01/03 18:00:00 1978/01/06 21:00:00 76 0.98 0.74% 11.6
6 2003/02/25 06:00:00 2003/02/28 01:00:00 68 0.914 0.89%9.67
7 1969/02/22 02:00:00 1969/02/26 21:00:00 116 0.828 1.04% 8.29
8 1958/02/03 04:00:00 1958/02/05 12:00:00 57 0.779 1.19%7.25
9 1978/02/27 09:00:00 1978/03/05 07:00:00 143 0.77 1.34%6.44
10 1965/11/22 04:00:00 1965/11/24 06:00:00 51 0.661 1.49% 5.8
11 1982/03/17 03:00:00 1982/03/19 08:00:00 54 0.661 1.64% 5.27
12 1986/09/23 23:00:00 1986/09/26 00:00:00 50 0.632 1.79% 4.83
13 1980/01/27 23:00:00 1980/01/31 04:00:00 78 0.609 1.93% 4.46
14 1952/01/16 07:00:00 1952/01/19 07:00:00 73 0.591 2.08% 4.14
15 2008/02/22 02:00:00 2008/02/24 18:00:00 65 0.482 2.23% 3.87
16 1991/02/27 18:00:00 1991/03/02 12:00:00 67 0.449 2.38% 3.63
17 1978/01/14 15:00:00 1978/01/18 03:00:00 85 0.443 2.53% 3.41
18 1986/02/14 22:00:00 1986/02/17 07:00:00 58 0.442 2.68% 3.22
19 1979/01/05 07:00:00 1979/01/07 10:00:00 52 0.436 2.83% 3.05
20 1968/03/07 23:00:00 1968/03/09 14:00:00 40 0.426 2.98% 2.9
21 2004/10/27 02:00:00 2004/10/28 19:00:00 42 0.417 3.13% 2.76
22 1962/01/20 12:00:00 1962/01/23 02:00:00 63 0.411 3.27% 2.64
23 2005/01/07 06:00:00 2005/01/12 08:00:00 123 0.404 3.42% 2.52
24 2005/02/18 04:00:00 2005/02/24 07:00:00 148 0.371 3.57% 2.42
25 1993/01/12 18:00:00 1993/01/19 14:00:00 165 0.36 3.72% 2.32
26 1995/03/11 01:00:00 1995/03/12 23:00:00 47 0.345 3.87% 2.23
27 1966/12/03 05:00:00 1966/12/07 12:00:00 104 0.342 4.02% 2.15
28 1996/11/21 15:00:00 1996/11/23 05:00:00 39 0.331 4.17% 2.07
29 1995/03/05 02:00:00 1995/03/07 02:00:00 49 0.302 4.32% 2
30 1998/02/22 07:00:00 1998/02/25 07:00:00 73 0.291 4.46% 1.93
31 1980/02/13 12:00:00 1980/02/22 05:00:00 210 0.284 4.61% 1.87
32 2007/11/30 08:00:00 2007/12/02 00:00:00 41 0.248 4.76% 1.81
33 1969/01/24 07:00:00 1969/01/29 01:00:00 115 0.246 4.91% 1.76
34 1991/12/29 15:00:00 1991/12/31 04:00:00 38 0.242 5.06% 1.71
Peak Flow Statistics Table Values
SWMM.out file name: V:\22\22081\Engineering\GPIP\Storm\Working Files\Hydmod\Current\22081 POST-PC1 - Copy.out
SWMM.out time stamp: 6/3/2025 6:29:35 PM
1/176/4/2025 11:02 AM
Excel Engineering
peakFlowStatisticsPostMitigated.csv
Rank Start Date End Date Duration (hr) Peak (cfs) Frequency (%) Return Period (Yr)
35 1998/02/03 05:00:00 1998/02/05 00:00:00 44 0.238 5.21% 1.66
36 1978/02/05 10:00:00 1978/02/14 12:00:00 219 0.237 5.36% 1.61
37 1967/01/22 16:00:00 1967/01/25 12:00:00 69 0.237 5.51% 1.57
38 1977/08/17 01:00:00 1977/08/18 15:00:00 39 0.217 5.65% 1.53
39 1980/01/09 01:00:00 1980/01/14 02:00:00 122 0.217 5.80% 1.49
40 1983/12/24 09:00:00 1983/12/27 13:00:00 77 0.188 5.95% 1.45
41 1997/01/12 14:00:00 1997/01/14 12:00:00 47 0.174 6.10% 1.42
42 1972/01/16 19:00:00 1972/01/19 17:00:00 71 0.167 6.25% 1.38
43 2004/10/18 07:00:00 2004/10/21 17:00:00 83 0.166 6.40% 1.35
44 1958/04/01 07:00:00 1958/04/04 11:00:00 77 0.164 6.55% 1.32
45 1965/11/14 19:00:00 1965/11/18 18:00:00 96 0.146 6.70% 1.29
46 1957/01/13 03:00:00 1957/01/14 09:00:00 31 0.145 6.85% 1.26
47 1980/03/02 20:00:00 1980/03/04 08:00:00 37 0.131 6.99% 1.23
48 1954/02/13 16:00:00 1954/02/15 02:00:00 35 0.124 7.14% 1.21
49 2008/01/05 03:00:00 2008/01/08 02:00:00 72 0.122 7.29% 1.18
50 1983/02/26 06:00:00 1983/03/05 04:00:00 167 0.122 7.44% 1.16
51 1985/11/29 06:00:00 1985/11/30 14:00:00 33 0.119 7.59% 1.14
52 2004/02/26 00:00:00 2004/02/27 10:00:00 35 0.116 7.74% 1.12
53 1970/12/16 22:00:00 1970/12/22 06:00:00 129 0.115 7.89% 1.09
54 1998/02/14 07:00:00 1998/02/20 02:00:00 140 0.112 8.04% 1.07
55 1969/02/06 07:00:00 1969/02/07 14:00:00 32 0.107 8.18% 1.06
56 1960/02/01 19:00:00 1960/02/03 00:00:00 30 0.106 8.33% 1.04
57 2000/10/29 21:00:00 2000/10/31 03:00:00 31 0.105 8.48% 1.02
58 1952/11/14 15:00:00 1952/11/16 22:00:00 56 0.104 8.63% 1
59 1988/12/24 19:00:00 1988/12/25 20:00:00 26 0.104 8.78% 0.98
60 1956/01/25 17:00:00 1956/01/28 07:00:00 63 0.103 8.93% 0.97
61 1992/02/12 12:00:00 1992/02/14 05:00:00 42 0.102 9.08% 0.95
62 1957/01/28 01:00:00 1957/01/30 12:00:00 60 0.102 9.23% 0.94
63 1960/01/10 11:00:00 1960/01/13 06:00:00 68 0.102 9.38% 0.92
64 1971/12/22 06:00:00 1971/12/26 04:00:00 95 0.101 9.52% 0.91
65 1993/02/07 21:00:00 1993/02/09 11:00:00 39 0.1 9.67% 0.89
66 1961/12/01 19:00:00 1961/12/03 12:00:00 42 0.099 9.82% 0.88
67 1985/11/11 09:00:00 1985/11/12 23:00:00 39 0.095 9.97% 0.87
68 1960/04/27 05:00:00 1960/04/28 07:00:00 27 0.094 10.12% 0.85
69 2003/02/11 13:00:00 2003/02/14 03:00:00 63 0.092 10.27% 0.84
70 1994/02/03 20:00:00 1994/02/05 07:00:00 36 0.092 10.42% 0.83
71 1963/09/17 07:00:00 1963/09/19 19:00:00 61 0.09 10.57% 0.82
72 2008/01/27 00:00:00 2008/01/29 02:00:00 51 0.088 10.71% 0.81
73 2004/12/28 08:00:00 2004/12/30 12:00:00 53 0.088 10.86% 0.8
74 1988/11/24 04:00:00 1988/11/26 06:00:00 51 0.087 11.01% 0.78
75 1963/03/17 00:00:00 1963/03/18 02:00:00 27 0.086 11.16% 0.77
76 1986/03/15 21:00:00 1986/03/17 07:00:00 35 0.086 11.31% 0.76
2/176/4/2025 11:02 AM
Excel Engineering
peakFlowStatisticsPostMitigated.csv
Rank Start Date End Date Duration (hr) Peak (cfs) Frequency (%) Return Period (Yr)
77 1986/11/18 02:00:00 1986/11/19 05:00:00 28 0.086 11.46% 0.75
78 2002/11/08 13:00:00 2002/11/09 19:00:00 31 0.085 11.61% 0.74
79 1967/12/18 15:00:00 1967/12/20 12:00:00 46 0.085 11.76% 0.73
80 2005/01/03 05:00:00 2005/01/05 02:00:00 46 0.085 11.90% 0.73
81 1954/01/18 18:00:00 1954/01/20 23:00:00 54 0.085 12.05% 0.72
82 1987/10/11 16:00:00 1987/10/13 17:00:00 50 0.084 12.20% 0.71
83 1993/02/18 12:00:00 1993/02/20 20:00:00 57 0.083 12.35% 0.7
84 1983/01/27 07:00:00 1983/01/30 01:00:00 67 0.083 12.50% 0.69
85 1981/03/19 19:00:00 1981/03/20 16:00:00 22 0.082 12.65% 0.68
86 1994/03/24 21:00:00 1994/03/26 02:00:00 30 0.081 12.80% 0.67
87 1958/03/15 15:00:00 1958/03/17 08:00:00 42 0.08 12.95% 0.67
88 1952/03/15 19:00:00 1952/03/17 09:00:00 39 0.079 13.10% 0.66
89 1978/09/05 17:00:00 1978/09/06 21:00:00 29 0.078 13.24% 0.65
90 1977/01/05 13:00:00 1977/01/08 02:00:00 62 0.078 13.39% 0.64
91 1967/03/13 10:00:00 1967/03/14 18:00:00 33 0.077 13.54% 0.64
92 1982/12/22 18:00:00 1982/12/23 18:00:00 25 0.077 13.69% 0.63
93 1958/02/19 08:00:00 1958/02/20 11:00:00 28 0.077 13.84% 0.62
94 1990/02/17 14:00:00 1990/02/19 01:00:00 36 0.077 13.99% 0.62
95 1952/03/07 08:00:00 1952/03/08 23:00:00 40 0.077 14.14% 0.61
96 1988/01/17 10:00:00 1988/01/18 13:00:00 28 0.077 14.29% 0.6
97 1956/04/12 21:00:00 1956/04/14 15:00:00 43 0.076 14.43% 0.6
98 1975/04/08 07:00:00 1975/04/10 00:00:00 42 0.076 14.58% 0.59
99 1981/11/26 23:00:00 1981/11/29 16:00:00 66 0.076 14.73% 0.59
100 1997/01/25 18:00:00 1997/01/27 08:00:00 39 0.076 14.88% 0.58
101 1963/11/20 02:00:00 1963/11/22 01:00:00 48 0.076 15.03% 0.57
102 1970/11/28 22:00:00 1970/12/01 18:00:00 69 0.076 15.18% 0.57
103 1952/11/30 01:00:00 1952/12/02 14:00:00 62 0.076 15.33% 0.56
104 1987/12/16 12:00:00 1987/12/18 07:00:00 44 0.076 15.48% 0.56
105 1995/01/10 14:00:00 1995/01/13 09:00:00 68 0.075 15.63% 0.55
106 1951/12/29 04:00:00 1951/12/31 10:00:00 55 0.075 15.77% 0.55
107 1965/12/09 07:00:00 1965/12/11 04:00:00 46 0.074 15.92% 0.54
108 1962/02/07 20:00:00 1962/02/09 18:00:00 47 0.074 16.07% 0.54
109 1985/12/11 03:00:00 1985/12/12 01:00:00 23 0.073 16.22% 0.53
110 2007/01/30 23:00:00 2007/01/31 16:00:00 18 0.073 16.37% 0.53
111 1954/11/11 02:00:00 1954/11/12 09:00:00 32 0.073 16.52% 0.52
112 1991/03/25 02:00:00 1991/03/27 22:00:00 69 0.073 16.67% 0.52
113 1963/02/09 17:00:00 1963/02/11 17:00:00 49 0.073 16.82% 0.51
114 2001/02/13 13:00:00 2001/02/15 15:00:00 51 0.073 16.96% 0.51
115 1958/04/06 17:00:00 1958/04/08 10:00:00 42 0.072 17.11% 0.5
116 1958/03/20 18:00:00 1958/03/23 02:00:00 57 0.072 17.26% 0.5
117 1993/01/06 01:00:00 1993/01/08 21:00:00 69 0.072 17.41% 0.5
118 1985/11/24 21:00:00 1985/11/26 02:00:00 30 0.072 17.56% 0.49
3/176/4/2025 11:02 AM
Excel Engineering
peakFlowStatisticsPostMitigated.csv
Rank Start Date End Date Duration (hr) Peak (cfs) Frequency (%) Return Period (Yr)
119 1997/01/15 14:00:00 1997/01/16 11:00:00 22 0.072 17.71% 0.49
120 1992/01/05 08:00:00 1992/01/08 18:00:00 83 0.071 17.86% 0.48
121 1970/02/28 13:00:00 1970/03/02 13:00:00 49 0.071 18.01% 0.48
122 1995/01/07 12:00:00 1995/01/09 02:00:00 39 0.071 18.15% 0.48
123 2001/01/10 20:00:00 2001/01/12 22:00:00 51 0.071 18.30% 0.47
124 1974/03/08 00:00:00 1974/03/09 05:00:00 30 0.071 18.45% 0.47
125 1959/02/11 08:00:00 1959/02/12 12:00:00 29 0.07 18.60% 0.46
126 1982/12/07 21:00:00 1982/12/08 18:00:00 22 0.069 18.75% 0.46
127 1965/04/07 03:00:00 1965/04/10 06:00:00 76 0.069 18.90% 0.46
128 1992/03/20 22:00:00 1992/03/23 19:00:00 70 0.069 19.05% 0.45
129 1988/12/20 22:00:00 1988/12/23 04:00:00 55 0.068 19.20% 0.45
130 1967/11/19 08:00:00 1967/11/22 00:00:00 65 0.068 19.35% 0.45
131 2005/02/11 02:00:00 2005/02/13 09:00:00 56 0.068 19.49% 0.44
132 1957/05/11 01:00:00 1957/05/11 22:00:00 22 0.067 19.64% 0.44
133 1983/11/24 20:00:00 1983/11/25 18:00:00 23 0.067 19.79% 0.44
134 1992/12/07 08:00:00 1992/12/08 11:00:00 28 0.067 19.94% 0.43
135 1988/04/20 00:00:00 1988/04/23 14:00:00 87 0.067 20.09% 0.43
136 2003/03/15 12:00:00 2003/03/17 04:00:00 41 0.067 20.24% 0.43
137 1973/11/22 23:00:00 1973/11/23 18:00:00 20 0.066 20.39% 0.42
138 1992/02/15 12:00:00 1992/02/16 14:00:00 27 0.066 20.54% 0.42
139 1958/01/25 03:00:00 1958/01/27 10:00:00 56 0.065 20.68% 0.42
140 1952/01/13 03:00:00 1952/01/14 04:00:00 26 0.064 20.83% 0.41
141 1988/04/14 19:00:00 1988/04/15 16:00:00 22 0.063 20.98% 0.41
142 1967/04/11 08:00:00 1967/04/12 03:00:00 20 0.063 21.13% 0.41
143 1955/01/18 15:00:00 1955/01/19 13:00:00 23 0.063 21.28% 0.41
144 2001/01/26 11:00:00 2001/01/28 00:00:00 38 0.063 21.43% 0.4
145 1978/01/09 14:00:00 1978/01/11 13:00:00 48 0.063 21.58% 0.4
146 1976/03/01 15:00:00 1976/03/03 04:00:00 38 0.062 21.73% 0.4
147 1974/12/04 07:00:00 1974/12/05 02:00:00 20 0.062 21.88% 0.4
148 1976/07/22 11:00:00 1976/07/23 05:00:00 19 0.062 22.02% 0.39
149 1981/12/30 07:00:00 1982/01/02 17:00:00 83 0.062 22.17% 0.39
150 1966/11/07 14:00:00 1966/11/08 12:00:00 23 0.062 22.32% 0.39
151 1994/02/17 10:00:00 1994/02/18 06:00:00 21 0.061 22.47% 0.38
152 2005/04/28 08:00:00 2005/04/29 00:00:00 17 0.061 22.62% 0.38
153 1959/12/24 08:00:00 1959/12/25 06:00:00 23 0.061 22.77% 0.38
154 1994/03/07 01:00:00 1994/03/07 23:00:00 23 0.061 22.92% 0.38
155 1983/04/20 03:00:00 1983/04/21 12:00:00 34 0.061 23.07% 0.37
156 1960/01/14 16:00:00 1960/01/15 17:00:00 26 0.061 23.21% 0.37
157 1976/02/04 09:00:00 1976/02/10 19:00:00 155 0.061 23.36% 0.37
158 1984/12/26 14:00:00 1984/12/28 12:00:00 47 0.061 23.51% 0.37
159 2004/12/31 13:00:00 2005/01/01 13:00:00 25 0.06 23.66% 0.37
160 1977/05/08 12:00:00 1977/05/09 22:00:00 35 0.06 23.81% 0.36
4/176/4/2025 11:02 AM
Excel Engineering
peakFlowStatisticsPostMitigated.csv
Rank Start Date End Date Duration (hr) Peak (cfs) Frequency (%) Return Period (Yr)
161 1991/03/19 00:00:00 1991/03/21 19:00:00 68 0.06 23.96% 0.36
162 1960/02/28 20:00:00 1960/03/01 16:00:00 45 0.06 24.11% 0.36
163 1976/07/15 12:00:00 1976/07/16 06:00:00 19 0.06 24.26% 0.36
164 1976/07/08 13:00:00 1976/07/09 05:00:00 17 0.06 24.40% 0.35
165 1965/03/31 14:00:00 1965/04/02 02:00:00 37 0.059 24.55% 0.35
166 1968/12/25 18:00:00 1968/12/26 15:00:00 22 0.059 24.70% 0.35
167 1990/01/16 23:00:00 1990/01/18 15:00:00 41 0.059 24.85% 0.35
168 1973/03/20 08:00:00 1973/03/21 01:00:00 18 0.059 25.00% 0.35
169 1974/01/07 14:00:00 1974/01/09 17:00:00 52 0.059 25.15% 0.34
170 1978/12/16 23:00:00 1978/12/19 19:00:00 69 0.058 25.30% 0.34
171 1964/11/17 13:00:00 1964/11/18 09:00:00 21 0.058 25.45% 0.34
172 1988/02/02 01:00:00 1988/02/03 07:00:00 31 0.058 25.60% 0.34
173 1975/03/08 07:00:00 1975/03/09 03:00:00 21 0.058 25.74% 0.34
174 1996/12/09 16:00:00 1996/12/12 09:00:00 66 0.057 25.89% 0.33
175 2004/02/22 06:00:00 2004/02/23 22:00:00 41 0.057 26.04% 0.33
176 1957/01/07 12:00:00 1957/01/08 11:00:00 24 0.057 26.19% 0.33
177 1961/01/26 09:00:00 1961/01/27 05:00:00 21 0.057 26.34% 0.33
178 1994/03/19 02:00:00 1994/03/20 15:00:00 38 0.056 26.49% 0.33
179 1972/11/14 14:00:00 1972/11/15 05:00:00 16 0.056 26.64% 0.32
180 1977/01/02 21:00:00 1977/01/03 19:00:00 23 0.056 26.79% 0.32
181 2001/02/25 09:00:00 2001/02/28 21:00:00 85 0.056 26.93% 0.32
182 1981/02/08 19:00:00 1981/02/09 21:00:00 27 0.056 27.08% 0.32
183 1977/03/24 21:00:00 1977/03/25 19:00:00 23 0.056 27.23% 0.32
184 1985/02/09 05:00:00 1985/02/10 02:00:00 22 0.055 27.38% 0.32
185 1959/02/21 09:00:00 1959/02/22 08:00:00 24 0.055 27.53% 0.31
186 1966/02/06 10:00:00 1966/02/08 12:00:00 51 0.054 27.68% 0.31
187 1976/09/10 04:00:00 1976/09/11 14:00:00 35 0.054 27.83% 0.31
188 1982/01/05 04:00:00 1982/01/06 04:00:00 25 0.054 27.98% 0.31
189 1979/03/17 05:00:00 1979/03/17 21:00:00 17 0.054 28.13% 0.31
190 1992/02/06 10:00:00 1992/02/07 20:00:00 35 0.054 28.27% 0.31
191 1981/01/28 06:00:00 1981/01/30 17:00:00 60 0.054 28.42% 0.3
192 2002/12/20 08:00:00 2002/12/22 00:00:00 41 0.054 28.57% 0.3
193 1965/12/14 15:00:00 1965/12/16 21:00:00 55 0.054 28.72% 0.3
194 1993/01/30 23:00:00 1993/01/31 14:00:00 16 0.053 28.87% 0.3
195 1972/11/16 10:00:00 1972/11/17 21:00:00 36 0.053 29.02% 0.3
196 1964/01/21 07:00:00 1964/01/22 22:00:00 40 0.053 29.17% 0.3
197 1978/03/30 15:00:00 1978/04/01 02:00:00 36 0.053 29.32% 0.29
198 1982/03/14 13:00:00 1982/03/15 13:00:00 25 0.053 29.46% 0.29
199 2006/04/04 17:00:00 2006/04/05 14:00:00 22 0.053 29.61% 0.29
200 1998/02/06 16:00:00 1998/02/09 09:00:00 66 0.053 29.76% 0.29
201 1986/03/08 15:00:00 1986/03/11 10:00:00 68 0.053 29.91% 0.29
202 1988/12/15 13:00:00 1988/12/17 05:00:00 41 0.053 30.06% 0.29
5/176/4/2025 11:02 AM
Excel Engineering
peakFlowStatisticsPostMitigated.csv
Rank Start Date End Date Duration (hr) Peak (cfs) Frequency (%) Return Period (Yr)
203 1999/01/25 05:00:00 1999/01/27 14:00:00 58 0.053 30.21% 0.29
204 1957/02/28 18:00:00 1957/03/01 23:00:00 30 0.052 30.36% 0.28
205 1973/02/11 06:00:00 1973/02/13 15:00:00 58 0.052 30.51% 0.28
206 1958/02/25 06:00:00 1958/02/25 21:00:00 16 0.052 30.65% 0.28
207 2006/10/14 01:00:00 2006/10/14 14:00:00 14 0.052 30.80% 0.28
208 1980/03/05 23:00:00 1980/03/07 00:00:00 26 0.051 30.95% 0.28
209 1979/11/07 18:00:00 1979/11/08 11:00:00 18 0.051 31.10% 0.28
210 1982/02/09 19:00:00 1982/02/11 08:00:00 38 0.051 31.25% 0.28
211 1995/04/18 10:00:00 1995/04/19 04:00:00 19 0.051 31.40% 0.28
212 1987/01/06 19:00:00 1987/01/07 18:00:00 24 0.051 31.55% 0.27
213 1965/02/06 00:00:00 1965/02/07 11:00:00 36 0.05 31.70% 0.27
214 1998/01/29 10:00:00 1998/01/30 09:00:00 24 0.05 31.85% 0.27
215 2006/02/27 19:00:00 2006/02/28 21:00:00 27 0.05 31.99% 0.27
216 1955/01/10 03:00:00 1955/01/11 02:00:00 24 0.05 32.14% 0.27
217 1951/12/11 22:00:00 1951/12/12 18:00:00 21 0.05 32.29% 0.27
218 1977/12/25 16:00:00 1977/12/30 10:00:00 115 0.05 32.44% 0.27
219 1981/02/28 12:00:00 1981/03/03 04:00:00 65 0.05 32.59% 0.27
220 1982/04/01 09:00:00 1982/04/02 02:00:00 18 0.05 32.74% 0.26
221 1971/02/17 05:00:00 1971/02/17 23:00:00 19 0.049 32.89% 0.26
222 1979/03/18 22:00:00 1979/03/21 08:00:00 59 0.049 33.04% 0.26
223 1952/01/25 03:00:00 1952/01/25 23:00:00 21 0.049 33.18% 0.26
224 1983/11/11 22:00:00 1983/11/13 10:00:00 37 0.049 33.33% 0.26
225 1965/12/29 18:00:00 1965/12/30 07:00:00 14 0.049 33.48% 0.26
226 1970/03/04 21:00:00 1970/03/05 12:00:00 16 0.049 33.63% 0.26
227 1971/04/14 11:00:00 1971/04/15 00:00:00 14 0.049 33.78% 0.26
228 1988/11/14 07:00:00 1988/11/14 20:00:00 14 0.049 33.93% 0.25
229 1957/12/05 03:00:00 1957/12/05 23:00:00 21 0.048 34.08% 0.25
230 1996/10/30 14:00:00 1996/10/31 04:00:00 15 0.048 34.23% 0.25
231 1983/03/24 03:00:00 1983/03/25 10:00:00 32 0.048 34.38% 0.25
232 1967/11/30 15:00:00 1967/12/01 04:00:00 14 0.048 34.52% 0.25
233 1962/03/18 18:00:00 1962/03/19 15:00:00 22 0.048 34.67% 0.25
234 1984/12/07 23:00:00 1984/12/08 13:00:00 15 0.048 34.82% 0.25
235 1979/03/01 09:00:00 1979/03/02 02:00:00 18 0.048 34.97% 0.25
236 1969/02/18 07:00:00 1969/02/20 13:00:00 55 0.048 35.12% 0.25
237 1990/04/04 08:00:00 1990/04/04 23:00:00 16 0.048 35.27% 0.25
238 1952/12/20 10:00:00 1952/12/21 01:00:00 16 0.047 35.42% 0.24
239 2001/12/09 10:00:00 2001/12/10 07:00:00 22 0.047 35.57% 0.24
240 1981/03/05 02:00:00 1981/03/05 23:00:00 22 0.047 35.71% 0.24
241 1991/01/09 14:00:00 1991/01/10 03:00:00 14 0.047 35.86% 0.24
242 1982/01/20 03:00:00 1982/01/21 21:00:00 43 0.047 36.01% 0.24
243 1989/03/25 12:00:00 1989/03/26 09:00:00 22 0.047 36.16% 0.24
244 1992/03/02 07:00:00 1992/03/03 07:00:00 25 0.047 36.31% 0.24
6/176/4/2025 11:02 AM
Excel Engineering
peakFlowStatisticsPostMitigated.csv
Rank Start Date End Date Duration (hr) Peak (cfs) Frequency (%) Return Period (Yr)
245 2002/12/16 15:00:00 2002/12/17 08:00:00 18 0.047 36.46% 0.24
246 1979/01/30 18:00:00 1979/02/02 22:00:00 77 0.046 36.61% 0.24
247 1984/11/24 16:00:00 1984/11/25 08:00:00 17 0.046 36.76% 0.24
248 2000/03/04 18:00:00 2000/03/06 07:00:00 38 0.046 36.90% 0.23
249 1980/01/17 19:00:00 1980/01/19 06:00:00 36 0.046 37.05% 0.23
250 1983/04/29 07:00:00 1983/04/30 03:00:00 21 0.046 37.20% 0.23
251 1992/12/27 19:00:00 1992/12/29 19:00:00 49 0.046 37.35% 0.23
252 1959/12/21 00:00:00 1959/12/21 20:00:00 21 0.046 37.50% 0.23
253 1999/04/11 21:00:00 1999/04/12 14:00:00 18 0.045 37.65% 0.23
254 1957/04/20 15:00:00 1957/04/21 05:00:00 15 0.045 37.80% 0.23
255 1976/12/30 14:00:00 1976/12/31 15:00:00 26 0.045 37.95% 0.23
256 1978/03/11 18:00:00 1978/03/12 21:00:00 28 0.045 38.10% 0.23
257 1983/12/03 15:00:00 1983/12/04 06:00:00 16 0.045 38.24% 0.23
258 1987/12/04 21:00:00 1987/12/05 11:00:00 15 0.045 38.39% 0.23
259 1993/03/28 02:00:00 1993/03/28 14:00:00 13 0.045 38.54% 0.22
260 1980/03/25 22:00:00 1980/03/26 11:00:00 14 0.045 38.69% 0.22
261 1951/08/28 09:00:00 1951/08/28 21:00:00 13 0.045 38.84% 0.22
262 1969/03/21 12:00:00 1969/03/22 05:00:00 18 0.044 38.99% 0.22
263 1981/02/25 20:00:00 1981/02/26 10:00:00 15 0.044 39.14% 0.22
264 1982/11/09 18:00:00 1982/11/11 00:00:00 31 0.044 39.29% 0.22
265 2007/04/20 15:00:00 2007/04/21 03:00:00 13 0.044 39.43% 0.22
266 1994/01/24 23:00:00 1994/01/26 08:00:00 34 0.044 39.58% 0.22
267 1954/03/16 23:00:00 1954/03/17 13:00:00 15 0.044 39.73% 0.22
268 1974/10/28 12:00:00 1974/10/29 21:00:00 34 0.044 39.88% 0.22
269 1995/01/23 22:00:00 1995/01/26 19:00:00 70 0.044 40.03% 0.22
270 1955/02/27 02:00:00 1955/02/28 07:00:00 30 0.044 40.18% 0.22
271 1969/01/14 00:00:00 1969/01/14 23:00:00 24 0.044 40.33% 0.21
272 1970/02/10 03:00:00 1970/02/11 14:00:00 36 0.044 40.48% 0.21
273 1986/01/30 04:00:00 1986/02/01 04:00:00 49 0.044 40.63% 0.21
274 1993/03/26 00:00:00 1993/03/26 18:00:00 19 0.043 40.77% 0.21
275 1954/03/20 10:00:00 1954/03/25 11:00:00 122 0.043 40.92% 0.21
276 1959/04/26 06:00:00 1959/04/26 17:00:00 12 0.043 41.07% 0.21
277 1973/03/11 11:00:00 1973/03/12 14:00:00 28 0.043 41.22% 0.21
278 1984/12/18 06:00:00 1984/12/20 11:00:00 54 0.043 41.37% 0.21
279 1998/11/08 08:00:00 1998/11/08 23:00:00 16 0.043 41.52% 0.21
280 1965/01/24 06:00:00 1965/01/24 18:00:00 13 0.043 41.67% 0.21
281 1966/01/30 07:00:00 1966/01/31 06:00:00 24 0.043 41.82% 0.21
282 1987/02/23 19:00:00 1987/02/26 00:00:00 54 0.043 41.96% 0.21
283 1993/06/05 14:00:00 1993/06/06 02:00:00 13 0.043 42.11% 0.21
284 2003/12/25 00:00:00 2003/12/26 05:00:00 30 0.043 42.26% 0.2
285 1975/03/10 11:00:00 1975/03/11 16:00:00 30 0.043 42.41% 0.2
286 1972/12/04 14:00:00 1972/12/05 04:00:00 15 0.042 42.56% 0.2
7/176/4/2025 11:02 AM
Excel Engineering
peakFlowStatisticsPostMitigated.csv
Rank Start Date End Date Duration (hr) Peak (cfs) Frequency (%) Return Period (Yr)
287 1973/03/08 11:00:00 1973/03/09 01:00:00 15 0.042 42.71% 0.2
288 1959/02/16 03:00:00 1959/02/17 06:00:00 28 0.042 42.86% 0.2
289 1960/09/11 04:00:00 1960/09/11 17:00:00 14 0.042 43.01% 0.2
290 1997/12/06 16:00:00 1997/12/07 21:00:00 30 0.042 43.15% 0.2
291 1957/10/14 04:00:00 1957/10/14 16:00:00 13 0.042 43.30% 0.2
292 1954/01/24 08:00:00 1954/01/25 14:00:00 31 0.042 43.45% 0.2
293 2006/03/10 16:00:00 2006/03/11 21:00:00 30 0.042 43.60% 0.2
294 1960/11/26 17:00:00 1960/11/27 06:00:00 14 0.041 43.75% 0.2
295 2001/11/24 15:00:00 2001/11/25 06:00:00 16 0.041 43.90% 0.2
296 1980/12/07 10:00:00 1980/12/07 22:00:00 13 0.041 44.05% 0.2
297 1986/12/06 07:00:00 1986/12/07 11:00:00 29 0.041 44.20% 0.2
298 1964/12/27 08:00:00 1964/12/28 18:00:00 35 0.041 44.35% 0.2
299 1958/03/06 09:00:00 1958/03/07 07:00:00 23 0.041 44.49% 0.19
300 2004/02/02 23:00:00 2004/02/04 01:00:00 27 0.041 44.64% 0.19
301 2001/04/07 17:00:00 2001/04/08 05:00:00 13 0.041 44.79% 0.19
302 1955/02/17 06:00:00 1955/02/17 19:00:00 14 0.041 44.94% 0.19
303 1957/03/16 09:00:00 1957/03/16 20:00:00 12 0.041 45.09% 0.19
304 1993/11/30 04:00:00 1993/11/30 15:00:00 12 0.04 45.24% 0.19
305 2004/12/05 11:00:00 2004/12/06 02:00:00 16 0.04 45.39% 0.19
306 1954/12/09 23:00:00 1954/12/10 13:00:00 15 0.04 45.54% 0.19
307 1999/02/04 15:00:00 1999/02/05 08:00:00 18 0.04 45.68% 0.19
308 1976/08/30 11:00:00 1976/08/30 21:00:00 11 0.04 45.83% 0.19
309 1994/02/07 06:00:00 1994/02/08 11:00:00 30 0.04 45.98% 0.19
310 1951/11/23 04:00:00 1951/11/23 15:00:00 12 0.04 46.13% 0.19
311 1955/04/30 20:00:00 1955/05/01 14:00:00 19 0.04 46.28% 0.19
312 1969/11/06 20:00:00 1969/11/07 19:00:00 24 0.04 46.43% 0.19
313 1978/03/09 16:00:00 1978/03/10 02:00:00 11 0.04 46.58% 0.19
314 1983/03/17 02:00:00 1983/03/19 07:00:00 54 0.04 46.73% 0.19
315 1983/02/02 15:00:00 1983/02/03 18:00:00 28 0.04 46.88% 0.18
316 1952/12/30 19:00:00 1952/12/31 12:00:00 18 0.04 47.02% 0.18
317 1986/04/06 04:00:00 1986/04/06 19:00:00 16 0.04 47.17% 0.18
318 1960/01/25 20:00:00 1960/01/26 10:00:00 15 0.039 47.32% 0.18
319 1979/02/21 01:00:00 1979/02/21 15:00:00 15 0.039 47.47% 0.18
320 1979/03/27 04:00:00 1979/03/28 19:00:00 40 0.039 47.62% 0.18
321 2000/02/20 13:00:00 2000/02/22 05:00:00 41 0.039 47.77% 0.18
322 2007/12/07 05:00:00 2007/12/09 05:00:00 49 0.039 47.92% 0.18
323 1980/03/10 15:00:00 1980/03/11 01:00:00 11 0.039 48.07% 0.18
324 1979/10/20 08:00:00 1979/10/21 00:00:00 17 0.039 48.21% 0.18
325 1987/04/04 15:00:00 1987/04/05 01:00:00 11 0.039 48.36% 0.18
326 1996/01/31 03:00:00 1996/02/01 14:00:00 36 0.039 48.51% 0.18
327 1993/02/23 18:00:00 1993/02/24 09:00:00 16 0.038 48.66% 0.18
328 1982/01/28 17:00:00 1982/01/29 09:00:00 17 0.038 48.81% 0.18
8/176/4/2025 11:02 AM
Excel Engineering
peakFlowStatisticsPostMitigated.csv
Rank Start Date End Date Duration (hr) Peak (cfs) Frequency (%) Return Period (Yr)
329 1998/01/09 12:00:00 1998/01/11 02:00:00 39 0.038 48.96% 0.18
330 2006/03/28 21:00:00 2006/03/29 12:00:00 16 0.038 49.11% 0.18
331 1959/12/10 00:00:00 1959/12/10 12:00:00 13 0.038 49.26% 0.18
332 1986/02/07 22:00:00 1986/02/08 21:00:00 24 0.038 49.40% 0.18
333 1955/01/16 08:00:00 1955/01/17 01:00:00 18 0.038 49.55% 0.17
334 1970/01/16 07:00:00 1970/01/17 05:00:00 23 0.038 49.70% 0.17
335 1960/11/05 20:00:00 1960/11/06 17:00:00 22 0.038 49.85% 0.17
336 2004/04/01 22:00:00 2004/04/02 07:00:00 10 0.038 50.00% 0.17
337 1963/11/15 17:00:00 1963/11/16 03:00:00 11 0.037 50.15% 0.17
338 1995/04/16 08:00:00 1995/04/17 05:00:00 22 0.037 50.30% 0.17
339 1961/11/25 02:00:00 1961/11/26 05:00:00 28 0.037 50.45% 0.17
340 1986/10/09 20:00:00 1986/10/11 08:00:00 37 0.037 50.60% 0.17
341 1965/04/03 05:00:00 1965/04/04 22:00:00 42 0.037 50.74% 0.17
342 1988/01/05 14:00:00 1988/01/06 02:00:00 13 0.037 50.89% 0.17
343 1957/01/26 04:00:00 1957/01/26 16:00:00 13 0.037 51.04% 0.17
344 1957/01/05 09:00:00 1957/01/05 20:00:00 12 0.037 51.19% 0.17
345 1995/02/14 04:00:00 1995/02/15 00:00:00 21 0.037 51.34% 0.17
346 1954/03/30 04:00:00 1954/03/30 13:00:00 10 0.036 51.49% 0.17
347 1979/02/14 03:00:00 1979/02/14 13:00:00 11 0.036 51.64% 0.17
348 1962/02/19 10:00:00 1962/02/21 14:00:00 53 0.036 51.79% 0.17
349 1999/03/25 14:00:00 1999/03/26 02:00:00 13 0.036 51.93% 0.17
350 1953/03/01 22:00:00 1953/03/02 08:00:00 11 0.036 52.08% 0.17
351 2008/02/03 07:00:00 2008/02/04 05:00:00 23 0.036 52.23% 0.17
352 1973/02/15 11:00:00 1973/02/15 20:00:00 10 0.035 52.38% 0.17
353 1982/11/29 12:00:00 1982/11/30 21:00:00 34 0.035 52.53% 0.16
354 1952/04/10 16:00:00 1952/04/11 04:00:00 13 0.035 52.68% 0.16
355 1984/10/17 07:00:00 1984/10/17 15:00:00 9 0.035 52.83% 0.16
356 1983/04/18 02:00:00 1983/04/18 16:00:00 15 0.035 52.98% 0.16
357 1984/12/16 02:00:00 1984/12/16 11:00:00 10 0.035 53.13% 0.16
358 1962/02/15 18:00:00 1962/02/16 21:00:00 28 0.035 53.27% 0.16
359 1975/02/03 08:00:00 1975/02/04 13:00:00 30 0.035 53.42% 0.16
360 1985/12/02 10:00:00 1985/12/03 07:00:00 22 0.035 53.57% 0.16
361 1998/03/31 14:00:00 1998/04/01 03:00:00 14 0.035 53.72% 0.16
362 1978/01/19 05:00:00 1978/01/19 19:00:00 15 0.035 53.87% 0.16
363 1983/03/21 04:00:00 1983/03/23 00:00:00 45 0.035 54.02% 0.16
364 1968/02/13 04:00:00 1968/02/13 15:00:00 12 0.034 54.17% 0.16
365 2000/10/27 08:00:00 2000/10/27 17:00:00 10 0.034 54.32% 0.16
366 1985/01/07 11:00:00 1985/01/08 10:00:00 24 0.034 54.46% 0.16
367 1995/03/21 12:00:00 1995/03/21 22:00:00 11 0.034 54.61% 0.16
368 1952/02/29 22:00:00 1952/03/01 17:00:00 20 0.034 54.76% 0.16
369 1953/01/06 16:00:00 1953/01/08 09:00:00 42 0.034 54.91% 0.16
370 1956/01/31 09:00:00 1956/01/31 18:00:00 10 0.034 55.06% 0.16
9/176/4/2025 11:02 AM
Excel Engineering
peakFlowStatisticsPostMitigated.csv
Rank Start Date End Date Duration (hr) Peak (cfs) Frequency (%) Return Period (Yr)
371 1980/10/16 05:00:00 1980/10/16 13:00:00 9 0.034 55.21% 0.16
372 1996/02/21 02:00:00 1996/02/22 03:00:00 26 0.034 55.36% 0.16
373 1997/01/23 06:00:00 1997/01/24 01:00:00 20 0.034 55.51% 0.16
374 1952/11/23 00:00:00 1952/11/23 13:00:00 14 0.034 55.65% 0.16
375 1971/12/27 15:00:00 1971/12/28 21:00:00 31 0.034 55.80% 0.16
376 1978/11/21 17:00:00 1978/11/22 05:00:00 13 0.033 55.95% 0.15
377 2007/12/18 23:00:00 2007/12/19 17:00:00 19 0.033 56.10% 0.15
378 2000/02/11 17:00:00 2000/02/14 19:00:00 75 0.033 56.25% 0.15
379 1979/01/09 10:00:00 1979/01/09 20:00:00 11 0.033 56.40% 0.15
380 1980/12/04 13:00:00 1980/12/05 13:00:00 25 0.033 56.55% 0.15
381 1990/01/31 00:00:00 1990/01/31 08:00:00 9 0.033 56.70% 0.15
382 1996/02/25 09:00:00 1996/02/28 04:00:00 68 0.033 56.85% 0.15
383 1980/04/23 04:00:00 1980/04/23 11:00:00 8 0.033 56.99% 0.15
384 1973/02/28 01:00:00 1973/02/28 13:00:00 13 0.033 57.14% 0.15
385 1974/12/28 08:00:00 1974/12/29 16:00:00 33 0.033 57.29% 0.15
386 1996/12/27 16:00:00 1996/12/28 11:00:00 20 0.033 57.44% 0.15
387 1964/03/23 00:00:00 1964/03/24 04:00:00 29 0.033 57.59% 0.15
388 1998/12/06 05:00:00 1998/12/06 13:00:00 9 0.033 57.74% 0.15
389 1958/03/27 13:00:00 1958/03/27 21:00:00 9 0.032 57.89% 0.15
390 1967/04/18 21:00:00 1967/04/20 03:00:00 31 0.032 58.04% 0.15
391 1995/01/21 03:00:00 1995/01/21 11:00:00 9 0.032 58.18% 0.15
392 1998/03/25 17:00:00 1998/03/27 02:00:00 34 0.032 58.33% 0.15
393 1972/11/11 08:00:00 1972/11/11 16:00:00 9 0.032 58.48% 0.15
394 1982/12/29 19:00:00 1982/12/30 03:00:00 9 0.032 58.63% 0.15
395 1957/10/31 00:00:00 1957/10/31 09:00:00 10 0.032 58.78% 0.15
396 1969/04/05 21:00:00 1969/04/06 04:00:00 8 0.032 58.93% 0.15
397 1954/01/12 15:00:00 1954/01/13 06:00:00 16 0.032 59.08% 0.15
398 1975/02/09 06:00:00 1975/02/10 05:00:00 24 0.032 59.23% 0.15
399 2005/12/31 20:00:00 2006/01/03 05:00:00 58 0.032 59.38% 0.15
400 1953/11/14 16:00:00 1953/11/15 11:00:00 20 0.031 59.52% 0.15
401 1982/09/26 04:00:00 1982/09/26 19:00:00 16 0.031 59.67% 0.15
402 1961/11/20 17:00:00 1961/11/21 00:00:00 8 0.031 59.82% 0.14
403 1975/11/27 18:00:00 1975/11/29 01:00:00 32 0.031 59.97% 0.14
404 1955/03/11 02:00:00 1955/03/11 09:00:00 8 0.031 60.12% 0.14
405 1983/11/20 08:00:00 1983/11/20 22:00:00 15 0.031 60.27% 0.14
406 2006/05/22 05:00:00 2006/05/22 13:00:00 9 0.031 60.42% 0.14
407 1962/03/06 08:00:00 1962/03/07 02:00:00 19 0.03 60.57% 0.14
408 1998/12/01 16:00:00 1998/12/02 00:00:00 9 0.03 60.71% 0.14
409 1960/02/08 22:00:00 1960/02/10 13:00:00 40 0.03 60.86% 0.14
410 1957/01/09 23:00:00 1957/01/10 15:00:00 17 0.03 61.01% 0.14
411 2007/08/26 11:00:00 2007/08/26 17:00:00 7 0.03 61.16% 0.14
412 1982/03/26 00:00:00 1982/03/26 11:00:00 12 0.03 61.31% 0.14
10/176/4/2025 11:02 AM
Excel Engineering
peakFlowStatisticsPostMitigated.csv
Rank Start Date End Date Duration (hr) Peak (cfs) Frequency (%) Return Period (Yr)
413 1957/12/15 09:00:00 1957/12/17 11:00:00 51 0.03 61.46% 0.14
414 1971/01/12 19:00:00 1971/01/13 04:00:00 10 0.03 61.61% 0.14
415 1971/02/23 04:00:00 1971/02/23 10:00:00 7 0.03 61.76% 0.14
416 1975/12/20 14:00:00 1975/12/20 23:00:00 10 0.03 61.90% 0.14
417 2005/03/22 20:00:00 2005/03/23 04:00:00 9 0.03 62.05% 0.14
418 1959/01/06 08:00:00 1959/01/06 14:00:00 7 0.03 62.20% 0.14
419 1976/04/15 15:00:00 1976/04/16 11:00:00 21 0.03 62.35% 0.14
420 2000/04/17 18:00:00 2000/04/18 11:00:00 18 0.03 62.50% 0.14
421 2006/12/10 01:00:00 2006/12/11 02:00:00 26 0.03 62.65% 0.14
422 1960/11/12 23:00:00 1960/11/13 05:00:00 7 0.03 62.80% 0.14
423 1973/03/05 08:00:00 1973/03/07 04:00:00 45 0.03 62.95% 0.14
424 1973/11/18 08:00:00 1973/11/19 01:00:00 18 0.03 63.10% 0.14
425 1996/01/21 18:00:00 1996/01/22 13:00:00 20 0.03 63.24% 0.14
426 1996/03/12 20:00:00 1996/03/13 15:00:00 20 0.03 63.39% 0.14
427 1969/01/18 21:00:00 1969/01/22 10:00:00 86 0.029 63.54% 0.14
428 1982/11/19 01:00:00 1982/11/20 11:00:00 35 0.029 63.69% 0.14
429 1995/03/23 09:00:00 1995/03/23 22:00:00 14 0.029 63.84% 0.14
430 1987/02/13 21:00:00 1987/02/14 05:00:00 9 0.029 63.99% 0.14
431 1993/12/11 16:00:00 1993/12/12 05:00:00 14 0.029 64.14% 0.14
432 2001/03/06 16:00:00 2001/03/07 22:00:00 31 0.029 64.29% 0.13
433 1952/03/12 21:00:00 1952/03/13 12:00:00 16 0.029 64.43% 0.13
434 1963/04/26 02:00:00 1963/04/26 09:00:00 8 0.029 64.58% 0.13
435 1983/02/06 12:00:00 1983/02/08 12:00:00 49 0.029 64.73% 0.13
436 1990/05/28 09:00:00 1990/05/28 19:00:00 11 0.029 64.88% 0.13
437 1987/03/22 01:00:00 1987/03/22 08:00:00 8 0.029 65.03% 0.13
438 1951/12/19 08:00:00 1951/12/19 16:00:00 9 0.029 65.18% 0.13
439 1975/04/17 08:00:00 1975/04/17 14:00:00 7 0.029 65.33% 0.13
440 1978/01/30 17:00:00 1978/01/31 04:00:00 12 0.029 65.48% 0.13
441 1974/03/02 10:00:00 1974/03/02 17:00:00 8 0.029 65.63% 0.13
442 1990/02/04 11:00:00 1990/02/04 19:00:00 9 0.029 65.77% 0.13
443 2007/02/28 05:00:00 2007/03/01 01:00:00 21 0.028 65.92% 0.13
444 1952/12/28 08:00:00 1952/12/28 18:00:00 11 0.028 66.07% 0.13
445 1985/01/28 17:00:00 1985/01/29 05:00:00 13 0.028 66.22% 0.13
446 1967/04/21 21:00:00 1967/04/22 06:00:00 10 0.028 66.37% 0.13
447 1983/03/06 05:00:00 1983/03/06 22:00:00 18 0.028 66.52% 0.13
448 1983/04/12 22:00:00 1983/04/13 10:00:00 13 0.028 66.67% 0.13
449 1994/01/27 14:00:00 1994/01/27 20:00:00 7 0.028 66.82% 0.13
450 1978/11/24 09:00:00 1978/11/24 18:00:00 10 0.028 66.96% 0.13
451 1959/02/08 04:00:00 1959/02/09 01:00:00 22 0.028 67.11% 0.13
452 2004/03/02 00:00:00 2004/03/02 08:00:00 9 0.028 67.26% 0.13
453 2001/03/10 16:00:00 2001/03/11 01:00:00 10 0.028 67.41% 0.13
454 2006/02/19 04:00:00 2006/02/19 15:00:00 12 0.027 67.56% 0.13
11/176/4/2025 11:02 AM
Excel Engineering
peakFlowStatisticsPostMitigated.csv
Rank Start Date End Date Duration (hr) Peak (cfs) Frequency (%) Return Period (Yr)
455 2007/02/11 11:00:00 2007/02/11 17:00:00 7 0.027 67.71% 0.13
456 1958/09/24 05:00:00 1958/09/24 10:00:00 6 0.027 67.86% 0.13
457 1986/03/13 18:00:00 1986/03/14 07:00:00 14 0.027 68.01% 0.13
458 1993/01/02 07:00:00 1993/01/02 17:00:00 11 0.027 68.15% 0.13
459 1982/01/10 19:00:00 1982/01/11 09:00:00 15 0.027 68.30% 0.13
460 1969/11/10 02:00:00 1969/11/10 09:00:00 8 0.027 68.45% 0.13
461 1997/12/18 16:00:00 1997/12/19 01:00:00 10 0.027 68.60% 0.13
462 1991/12/28 02:00:00 1991/12/28 08:00:00 7 0.027 68.75% 0.13
463 1968/04/01 21:00:00 1968/04/02 02:00:00 6 0.027 68.90% 0.13
464 1983/12/09 16:00:00 1983/12/09 21:00:00 6 0.027 69.05% 0.13
465 1988/12/18 12:00:00 1988/12/19 01:00:00 14 0.027 69.20% 0.13
466 1963/04/17 05:00:00 1963/04/17 14:00:00 10 0.027 69.35% 0.12
467 1995/01/16 10:00:00 1995/01/16 15:00:00 6 0.027 69.49% 0.12
468 1977/12/18 06:00:00 1977/12/18 11:00:00 6 0.026 69.64% 0.12
469 1973/02/06 03:00:00 1973/02/07 09:00:00 31 0.026 69.79% 0.12
470 1997/01/02 04:00:00 1997/01/03 15:00:00 36 0.026 69.94% 0.12
471 1970/01/10 01:00:00 1970/01/10 12:00:00 12 0.026 70.09% 0.12
472 1983/02/24 09:00:00 1983/02/25 03:00:00 19 0.026 70.24% 0.12
473 1964/12/31 21:00:00 1965/01/01 03:00:00 7 0.026 70.39% 0.12
474 1967/03/31 11:00:00 1967/03/31 17:00:00 7 0.026 70.54% 0.12
475 1984/12/10 19:00:00 1984/12/11 10:00:00 16 0.026 70.68% 0.12
476 1952/03/10 20:00:00 1952/03/11 04:00:00 9 0.026 70.83% 0.12
477 1989/01/07 15:00:00 1989/01/07 21:00:00 7 0.026 70.98% 0.12
478 1995/03/03 11:00:00 1995/03/03 16:00:00 6 0.026 71.13% 0.12
479 1957/02/23 08:00:00 1957/02/23 15:00:00 8 0.026 71.28% 0.12
480 1965/03/12 19:00:00 1965/03/13 22:00:00 28 0.026 71.43% 0.12
481 1987/11/04 19:00:00 1987/11/05 13:00:00 19 0.026 71.58% 0.12
482 1996/12/06 01:00:00 1996/12/06 12:00:00 12 0.026 71.73% 0.12
483 2005/10/16 19:00:00 2005/10/18 13:00:00 43 0.026 71.88% 0.12
484 1955/04/22 05:00:00 1955/04/22 12:00:00 8 0.025 72.02% 0.12
485 1985/02/02 03:00:00 1985/02/02 16:00:00 14 0.025 72.17% 0.12
486 1992/03/27 05:00:00 1992/03/27 10:00:00 6 0.025 72.32% 0.12
487 2008/01/23 19:00:00 2008/01/24 02:00:00 8 0.025 72.47% 0.12
488 1998/05/12 18:00:00 1998/05/12 23:00:00 6 0.025 72.62% 0.12
489 1957/10/21 04:00:00 1957/10/21 09:00:00 6 0.025 72.77% 0.12
490 1977/01/29 02:00:00 1977/01/29 07:00:00 6 0.025 72.92% 0.12
491 1963/09/04 10:00:00 1963/09/04 16:00:00 7 0.025 73.07% 0.12
492 1986/02/13 08:00:00 1986/02/13 17:00:00 10 0.025 73.21% 0.12
493 2001/02/20 16:00:00 2001/02/21 00:00:00 9 0.025 73.36% 0.12
494 1955/11/17 12:00:00 1955/11/17 21:00:00 10 0.025 73.51% 0.12
495 1964/11/10 17:00:00 1964/11/10 22:00:00 6 0.025 73.66% 0.12
496 1993/01/10 11:00:00 1993/01/10 17:00:00 7 0.025 73.81% 0.12
12/176/4/2025 11:02 AM
Excel Engineering
peakFlowStatisticsPostMitigated.csv
Rank Start Date End Date Duration (hr) Peak (cfs) Frequency (%) Return Period (Yr)
497 1998/04/11 17:00:00 1998/04/11 23:00:00 7 0.025 73.96% 0.12
498 1963/02/14 10:00:00 1963/02/14 15:00:00 6 0.024 74.11% 0.12
499 1955/01/30 23:00:00 1955/01/31 11:00:00 13 0.024 74.26% 0.12
500 1955/11/14 08:00:00 1955/11/14 12:00:00 5 0.024 74.40% 0.12
501 1992/03/08 01:00:00 1992/03/08 12:00:00 12 0.024 74.55% 0.12
502 1990/01/14 04:00:00 1990/01/14 14:00:00 11 0.024 74.70% 0.12
503 1990/04/17 09:00:00 1990/04/17 17:00:00 9 0.024 74.85% 0.12
504 1991/03/15 14:00:00 1991/03/15 18:00:00 5 0.024 75.00% 0.12
505 2007/02/19 07:00:00 2007/02/19 12:00:00 6 0.024 75.15% 0.12
506 1963/03/28 10:00:00 1963/03/28 16:00:00 7 0.024 75.30% 0.12
507 1951/12/05 00:00:00 1951/12/05 10:00:00 11 0.023 75.45% 0.11
508 1957/05/21 06:00:00 1957/05/21 10:00:00 5 0.023 75.60% 0.11
509 1989/02/03 21:00:00 1989/02/04 20:00:00 24 0.023 75.74% 0.11
510 1958/03/11 01:00:00 1958/03/12 07:00:00 31 0.023 75.89% 0.11
511 2006/03/21 01:00:00 2006/03/21 07:00:00 7 0.023 76.04% 0.11
512 1987/10/31 06:00:00 1987/11/01 02:00:00 21 0.023 76.19% 0.11
513 2001/02/23 16:00:00 2001/02/23 23:00:00 8 0.023 76.34% 0.11
514 1980/03/21 20:00:00 1980/03/22 02:00:00 7 0.023 76.49% 0.11
515 1998/01/03 17:00:00 1998/01/04 20:00:00 28 0.023 76.64% 0.11
516 2001/11/29 16:00:00 2001/11/29 23:00:00 8 0.023 76.79% 0.11
517 2006/12/27 07:00:00 2006/12/27 11:00:00 5 0.023 76.93% 0.11
518 1996/01/16 20:00:00 1996/01/17 01:00:00 6 0.022 77.08% 0.11
519 1998/03/13 18:00:00 1998/03/14 22:00:00 29 0.022 77.23% 0.11
520 1953/04/27 21:00:00 1953/04/28 03:00:00 7 0.022 77.38% 0.11
521 2008/02/20 10:00:00 2008/02/20 16:00:00 7 0.022 77.53% 0.11
522 1955/01/01 23:00:00 1955/01/02 07:00:00 9 0.022 77.68% 0.11
523 1996/03/04 22:00:00 1996/03/05 02:00:00 5 0.022 77.83% 0.11
524 1992/12/18 01:00:00 1992/12/18 05:00:00 5 0.022 77.98% 0.11
525 1989/02/09 15:00:00 1989/02/10 08:00:00 18 0.022 78.13% 0.11
526 1984/12/03 09:00:00 1984/12/03 13:00:00 5 0.022 78.27% 0.11
527 1989/01/23 20:00:00 1989/01/24 00:00:00 5 0.022 78.42% 0.11
528 1978/11/11 17:00:00 1978/11/12 11:00:00 19 0.022 78.57% 0.11
529 2000/02/23 17:00:00 2000/02/23 22:00:00 6 0.022 78.72% 0.11
530 1979/02/23 01:00:00 1979/02/23 08:00:00 8 0.022 78.87% 0.11
531 2001/12/04 16:00:00 2001/12/04 22:00:00 7 0.022 79.02% 0.11
532 1962/01/13 01:00:00 1962/01/13 04:00:00 4 0.022 79.17% 0.11
533 1989/02/02 08:00:00 1989/02/02 12:00:00 5 0.022 79.32% 0.11
534 1990/06/10 07:00:00 1990/06/10 16:00:00 10 0.021 79.46% 0.11
535 1972/12/07 07:00:00 1972/12/08 15:00:00 33 0.021 79.61% 0.11
536 1968/11/14 19:00:00 1968/11/15 01:00:00 7 0.021 79.76% 0.11
537 1986/03/12 11:00:00 1986/03/12 17:00:00 7 0.021 79.91% 0.11
538 1996/01/25 13:00:00 1996/01/25 17:00:00 5 0.021 80.06% 0.11
13/176/4/2025 11:02 AM
Excel Engineering
peakFlowStatisticsPostMitigated.csv
Rank Start Date End Date Duration (hr) Peak (cfs) Frequency (%) Return Period (Yr)
539 2007/02/22 21:00:00 2007/02/23 00:00:00 4 0.021 80.21% 0.11
540 1957/06/10 04:00:00 1957/06/10 07:00:00 4 0.021 80.36% 0.11
541 1957/01/20 17:00:00 1957/01/20 21:00:00 5 0.02 80.51% 0.11
542 1966/10/10 14:00:00 1966/10/10 17:00:00 4 0.02 80.65% 0.11
543 1967/11/26 18:00:00 1967/11/26 21:00:00 4 0.02 80.80% 0.11
544 1975/12/12 17:00:00 1975/12/12 20:00:00 4 0.02 80.95% 0.11
545 1975/03/22 09:00:00 1975/03/22 12:00:00 4 0.02 81.10% 0.11
546 1992/02/10 01:00:00 1992/02/10 08:00:00 8 0.02 81.25% 0.11
547 1958/02/13 05:00:00 1958/02/13 09:00:00 5 0.019 81.40% 0.11
548 1974/03/27 08:00:00 1974/03/27 11:00:00 4 0.019 81.55% 0.11
549 1983/01/22 14:00:00 1983/01/23 15:00:00 26 0.019 81.70% 0.11
550 1987/03/06 01:00:00 1987/03/06 16:00:00 16 0.019 81.85% 0.11
551 1953/02/23 11:00:00 1953/02/23 21:00:00 11 0.019 81.99% 0.11
552 1988/12/27 22:00:00 1988/12/28 13:00:00 16 0.019 82.14% 0.11
553 1993/12/14 18:00:00 1993/12/14 22:00:00 5 0.019 82.29% 0.11
554 1965/12/31 23:00:00 1966/01/01 03:00:00 5 0.019 82.44% 0.11
555 1965/12/22 01:00:00 1965/12/22 11:00:00 11 0.019 82.59% 0.11
556 1962/02/24 22:00:00 1962/02/25 01:00:00 4 0.019 82.74% 0.1
557 1965/12/12 18:00:00 1965/12/13 13:00:00 20 0.019 82.89% 0.1
558 1956/02/24 09:00:00 1956/02/24 13:00:00 5 0.019 83.04% 0.1
559 1994/12/25 03:00:00 1994/12/25 07:00:00 5 0.019 83.18% 0.1
560 1971/10/17 00:00:00 1971/10/17 07:00:00 8 0.018 83.33% 0.1
561 1987/03/15 09:00:00 1987/03/15 12:00:00 4 0.018 83.48% 0.1
562 1989/03/02 18:00:00 1989/03/02 21:00:00 4 0.018 83.63% 0.1
563 1984/01/16 07:00:00 1984/01/16 10:00:00 4 0.018 83.78% 0.1
564 2006/12/17 00:00:00 2006/12/17 05:00:00 6 0.018 83.93% 0.1
565 1977/02/24 15:00:00 1977/02/25 00:00:00 10 0.018 84.08% 0.1
566 1962/03/22 23:00:00 1962/03/23 02:00:00 4 0.018 84.23% 0.1
567 1982/03/28 20:00:00 1982/03/29 03:00:00 8 0.018 84.38% 0.1
568 1952/12/17 12:00:00 1952/12/17 16:00:00 5 0.018 84.52% 0.1
569 1973/01/10 00:00:00 1973/01/10 03:00:00 4 0.018 84.67% 0.1
570 1976/04/13 08:00:00 1976/04/13 13:00:00 6 0.018 84.82% 0.1
571 1987/12/29 12:00:00 1987/12/30 06:00:00 19 0.018 84.97% 0.1
572 2004/11/21 07:00:00 2004/11/21 10:00:00 4 0.018 85.12% 0.1
573 1995/12/23 10:00:00 1995/12/23 12:00:00 3 0.018 85.27% 0.1
574 1999/01/31 10:00:00 1999/01/31 12:00:00 3 0.017 85.42% 0.1
575 1952/12/06 04:00:00 1952/12/06 07:00:00 4 0.017 85.57% 0.1
576 1965/11/25 10:00:00 1965/11/25 14:00:00 5 0.017 85.71% 0.1
577 1978/04/08 12:00:00 1978/04/08 18:00:00 7 0.017 85.86% 0.1
578 1992/01/03 09:00:00 1992/01/04 05:00:00 21 0.017 86.01% 0.1
579 2007/04/23 00:00:00 2007/04/23 02:00:00 3 0.017 86.16% 0.1
580 1979/12/21 11:00:00 1979/12/21 13:00:00 3 0.017 86.31% 0.1
14/176/4/2025 11:02 AM
Excel Engineering
peakFlowStatisticsPostMitigated.csv
Rank Start Date End Date Duration (hr) Peak (cfs) Frequency (%) Return Period (Yr)
581 1987/03/24 22:00:00 1987/03/25 22:00:00 25 0.017 86.46% 0.1
582 1998/11/28 18:00:00 1998/11/29 02:00:00 9 0.017 86.61% 0.1
583 1983/01/24 18:00:00 1983/01/25 18:00:00 25 0.017 86.76% 0.1
584 1983/01/18 10:00:00 1983/01/19 11:00:00 26 0.016 86.90% 0.1
585 1997/02/10 21:00:00 1997/02/11 00:00:00 4 0.016 87.05% 0.1
586 1957/04/22 12:00:00 1957/04/22 14:00:00 3 0.016 87.20% 0.1
587 1970/01/11 17:00:00 1970/01/11 22:00:00 6 0.016 87.35% 0.1
588 1996/02/03 12:00:00 1996/02/03 14:00:00 3 0.016 87.50% 0.1
589 2005/03/04 21:00:00 2005/03/05 03:00:00 7 0.016 87.65% 0.1
590 1964/03/02 12:00:00 1964/03/02 14:00:00 3 0.016 87.80% 0.1
591 1966/01/27 06:00:00 1966/01/27 08:00:00 3 0.016 87.95% 0.1
592 1973/02/03 21:00:00 1973/02/03 23:00:00 3 0.016 88.10% 0.1
593 1998/03/28 17:00:00 1998/03/28 20:00:00 4 0.016 88.24% 0.1
594 1996/01/28 06:00:00 1996/01/28 08:00:00 3 0.015 88.39% 0.1
595 1978/04/15 20:00:00 1978/04/15 22:00:00 3 0.015 88.54% 0.1
596 1984/12/12 20:00:00 1984/12/12 22:00:00 3 0.015 88.69% 0.1
597 2001/04/10 17:00:00 2001/04/10 19:00:00 3 0.015 88.84% 0.1
598 1988/08/24 05:00:00 1988/08/24 16:00:00 12 0.015 88.99% 0.1
599 1987/12/19 18:00:00 1987/12/19 20:00:00 3 0.015 89.14% 0.1
600 1974/01/01 07:00:00 1974/01/01 08:00:00 2 0.015 89.29% 0.1
601 1987/11/02 04:00:00 1987/11/02 06:00:00 3 0.015 89.43% 0.1
602 1997/01/22 02:00:00 1997/01/22 04:00:00 3 0.015 89.58% 0.1
603 1967/12/08 00:00:00 1967/12/08 09:00:00 10 0.015 89.73% 0.1
604 1978/11/13 20:00:00 1978/11/13 22:00:00 3 0.015 89.88% 0.1
605 1978/11/15 09:00:00 1978/11/15 11:00:00 3 0.015 90.03% 0.1
606 1955/12/04 10:00:00 1955/12/04 11:00:00 2 0.015 90.18% 0.1
607 1975/03/14 02:00:00 1975/03/14 04:00:00 3 0.014 90.33% 0.1
608 1985/02/03 21:00:00 1985/02/03 23:00:00 3 0.014 90.48% 0.1
609 1999/01/20 15:00:00 1999/01/20 17:00:00 3 0.014 90.63% 0.1
610 1978/03/22 23:00:00 1978/03/23 15:00:00 17 0.014 90.77% 0.1
611 1965/01/07 10:00:00 1965/01/07 11:00:00 2 0.014 90.92% 0.1
612 1979/12/25 10:00:00 1979/12/25 11:00:00 2 0.014 91.07% 0.1
613 1990/01/22 11:00:00 1990/01/22 12:00:00 2 0.014 91.22% 0.1
614 1976/07/27 00:00:00 1976/07/27 02:00:00 3 0.014 91.37% 0.09
615 1977/03/16 22:00:00 1977/03/22 14:00:00 137 0.014 91.52% 0.09
616 1983/12/19 15:00:00 1983/12/19 16:00:00 2 0.014 91.67% 0.09
617 1984/04/27 23:00:00 1984/04/28 00:00:00 2 0.014 91.82% 0.09
618 1967/01/31 02:00:00 1967/01/31 05:00:00 4 0.014 91.96% 0.09
619 1953/12/04 10:00:00 1953/12/04 11:00:00 2 0.014 92.11% 0.09
620 2000/03/08 17:00:00 2000/03/08 19:00:00 3 0.014 92.26% 0.09
621 2001/12/21 17:00:00 2001/12/21 19:00:00 3 0.014 92.41% 0.09
622 1977/12/23 04:00:00 1977/12/23 04:00:00 1 0.014 92.56% 0.09
15/176/4/2025 11:02 AM
Excel Engineering
peakFlowStatisticsPostMitigated.csv
Rank Start Date End Date Duration (hr) Peak (cfs) Frequency (%) Return Period (Yr)
623 1982/09/17 12:00:00 1982/09/17 14:00:00 3 0.014 92.71% 0.09
624 1989/05/15 06:00:00 1989/05/15 08:00:00 3 0.014 92.86% 0.09
625 1995/01/15 03:00:00 1995/01/15 04:00:00 2 0.014 93.01% 0.09
626 1983/10/08 03:00:00 1983/10/08 03:00:00 1 0.013 93.15% 0.09
627 1987/02/05 12:00:00 1987/02/05 12:00:00 1 0.013 93.30% 0.09
628 1962/02/11 05:00:00 1962/02/11 06:00:00 2 0.013 93.45% 0.09
629 1969/03/10 18:00:00 1969/03/10 19:00:00 2 0.013 93.60% 0.09
630 1983/12/15 14:00:00 1983/12/15 14:00:00 1 0.013 93.75% 0.09
631 1991/10/27 02:00:00 1991/10/27 12:00:00 11 0.013 93.90% 0.09
632 1957/11/14 18:00:00 1957/11/14 19:00:00 2 0.013 94.05% 0.09
633 1987/12/11 06:00:00 1987/12/11 06:00:00 1 0.013 94.20% 0.09
634 2006/03/03 15:00:00 2006/03/03 16:00:00 2 0.013 94.35% 0.09
635 1979/01/25 15:00:00 1979/01/25 15:00:00 1 0.013 94.49% 0.09
636 1983/01/05 09:00:00 1983/01/05 09:00:00 1 0.013 94.64% 0.09
637 1969/03/13 02:00:00 1969/03/13 05:00:00 4 0.013 94.79% 0.09
638 1976/11/12 06:00:00 1976/11/12 06:00:00 1 0.013 94.94% 0.09
639 1992/03/31 15:00:00 1992/03/31 15:00:00 1 0.013 95.09% 0.09
640 2004/01/02 21:00:00 2004/01/02 22:00:00 2 0.013 95.24% 0.09
641 2004/12/08 08:00:00 2004/12/08 09:00:00 2 0.013 95.39% 0.09
642 1987/11/17 22:00:00 1987/11/17 22:00:00 1 0.013 95.54% 0.09
643 1979/11/12 12:00:00 1979/11/12 12:00:00 1 0.012 95.68% 0.09
644 1992/03/29 13:00:00 1992/03/29 13:00:00 1 0.012 95.83% 0.09
645 1953/01/13 21:00:00 1953/01/13 23:00:00 3 0.012 95.98% 0.09
646 1969/12/09 01:00:00 1969/12/09 02:00:00 2 0.012 96.13% 0.09
647 1960/11/03 21:00:00 1960/11/03 21:00:00 1 0.012 96.28% 0.09
648 1960/12/03 04:00:00 1960/12/03 04:00:00 1 0.012 96.43% 0.09
649 1955/04/26 12:00:00 1955/04/26 12:00:00 1 0.012 96.58% 0.09
650 1983/05/01 09:00:00 1983/05/02 08:00:00 24 0.012 96.73% 0.09
651 1984/01/04 16:00:00 1984/01/04 16:00:00 1 0.012 96.88% 0.09
652 1985/03/28 12:00:00 1985/03/28 12:00:00 1 0.012 97.02% 0.09
653 1954/12/04 00:00:00 1954/12/04 00:00:00 1 0.012 97.17% 0.09
654 1964/11/09 15:00:00 1964/11/09 15:00:00 1 0.012 97.32% 0.09
655 1975/01/30 16:00:00 1975/01/30 17:00:00 2 0.012 97.47% 0.09
656 1983/11/18 00:00:00 1983/11/18 00:00:00 1 0.012 97.62% 0.09
657 1989/01/05 19:00:00 1989/01/05 19:00:00 1 0.012 97.77% 0.09
658 1958/01/30 13:00:00 1958/01/30 14:00:00 2 0.012 97.92% 0.09
659 2000/11/11 01:00:00 2000/11/11 02:00:00 2 0.011 98.07% 0.09
660 2006/03/07 01:00:00 2006/03/07 02:00:00 2 0.011 98.21% 0.09
661 1957/11/04 06:00:00 1957/11/04 06:00:00 1 0.011 98.36% 0.09
662 1978/04/02 19:00:00 1978/04/02 19:00:00 1 0.011 98.51% 0.09
663 1983/03/28 08:00:00 1983/03/28 08:00:00 1 0.011 98.66% 0.09
664 2007/02/13 22:00:00 2007/02/13 22:00:00 1 0.011 98.81% 0.09
16/176/4/2025 11:02 AM
Excel Engineering
peakFlowStatisticsPostMitigated.csv
Rank Start Date End Date Duration (hr) Peak (cfs) Frequency (%) Return Period (Yr)
665 1957/01/24 10:00:00 1957/01/24 10:00:00 1 0.011 98.96% 0.09
666 1984/11/16 15:00:00 1984/11/16 15:00:00 1 0.011 99.11% 0.09
667 1960/03/28 05:00:00 1960/03/28 05:00:00 1 0.011 99.26% 0.09
668 1993/02/26 21:00:00 1993/02/26 22:00:00 2 0.011 99.40% 0.09
669 1998/12/19 20:00:00 1998/12/19 20:00:00 1 0.011 99.55% 0.09
670 1971/12/13 06:00:00 1971/12/13 07:00:00 2 0.011 99.70% 0.09
671 1955/12/07 02:00:00 1955/12/07 02:00:00 1 0.01 99.85% 0.09
-------------End of Data-----------------
17/176/4/2025 11:02 AM
Excel Engineering
Development of the Flow Duration Statistics
Similar to the Peak Flow Statistics, the flow duration statistics are also developed directly from the SWMM
binary output file. It should be noted right from the start that the “durations” that we are talking about in
this section have nothing to do with the “storm durations” presented in the peak flow statistics section.
Other than using the same sequence of letters for the word, the two concepts have nothing to do with
each other and the reader is cautioned not to confuse the two. The goal of the flow duration statistics is
to determine, for the flow rates that fall within the hydromorphologicaly significant range, the length of
time that each of those flow rates occur. Since the amount of sediment transported by a river or stream is
proportional to the velocity of the water flowing and the length of time that velocity of flow acts on the
sediment, knowing the velocity and length of time for each flow rate is very useful.
Methodology
The methodology for determining the flow duration curves comes from a document developed by the U.S.
Geological Survey (USGS). The first stop on the journey to find this document was a link to the USGS
water site (http://www.usgs.gov/water/). This link is found in Appendix E (SDHMP Continuous Simulation
Modeling Primer), found in the County Hydromodification Management Plan1. On this web site a search
for “Flow Duration Curves” leads to USGS Publication 1542-A, Flow-duration curves, by James K. Searcy
1959 (http://pubs.er.usgs.gov/publication/wsp1542A). In this publication the development of the flow
duration curves is discussed in detail.
In Pub 1542-A, beginning on page 7 an example problem is used to illustrate the compilation of data used
to create the flow duration plots. On page 8 a completed form 9-217-c form shows the monthly tabulation
of flow rates for Bowie Creek near Hattiesburg, Miss. For each flow range the number of readings is
tabulated and then the total number of each flow rate is totaled for the year. It should be noted that while
this example is for a stream with a minimum flow rate of 100cfs, for the purposes of run-off studies in
Southern California the minimum flow rate of zero (0) cfs is the common low flow value. Once each of the
year’s data has been compiled the summary numbers from each year are transferred to form 9-217-d.
On this form the total number of each flow rate is again totaled and the percentage of time exceeded
calculated (as will be explained later under the discussion of our calculations). Once the data has been
compiled a graph of Discharge Rate vs. Percent Time Exceeded is developed. As will be explained in the
next section, the use of these curves leads to the amount of time each particular flow can be expected to
occur (based on historical data).
How to Read the Graphs2
Figure 1 shows a flow duration curve for a hypothetical development. The three curves show what
percentage of the time a range of flow rates are exceeded for three different conditions: pre-project, post-
1 FINAL HYDROMODIFICATION MANAGEMENT PLAN, Prepared for County of San Diego, California, March 2011, by Brown and
Caldwell Engineering of San Diego.
(http://www.projectcleanwater.org/images/stories/Docs/LDS/HMP/0311_SD_HMP_wAppendices.pdf)
2 The graph and the explanation were taken directly from Appendix E of the Hydromodification Plan
Excel Engineering
project and post-project with storm water mitigation. Under pre-project conditions the minimum
geomorphically significant flow rate is 0.10cfs (assumed) and as read from the graph, flows would equal
or exceed this value about 0.14% of the time (or about 12 hours per year) (0.0014 x 365days x 24
hour/day). For post-project conditions, this flow rate would occur more often – about 0.38% of the time
(or about 33 hours per year) (0.0038 x 365days x 24 hour/day). This increase in the duration of the
geomorphically significant flow after development illustrates why duration control is closely linked to
protecting creeks from accelerated erosion.
Development of Flow Duration Curves
The first step in developing the flow duration curves is to count the number of occurrences of each flow
rate. This is done by first rounding every non-zero flow value to an appropriate number of decimal places
(say two places). This in effect groups each flow into closely related values or “bins” as they are referred
to in publication 9-217d. Then the entire runoff record is queried for each value and the number of each
value counted. The next step is to enter the results of the query into a grid patterned after form 9-217d.
The data is entered in ascending order starting with the lowest flow first. The grid is composed of four
columns. They are (from left to right) Discharge Rate, Number of Periods (count), Total Periods
Exceeding (the total number of periods equal to or exceeding this value), and Percent Time Exceeded.
Starting at the top row (row 1), the flow rate (which is often times zero) is entered with the corresponding
number of times that value was found. The next column is the total number of values greater than or
equal to that flow rate. For the first flow rate point, by definition all flow rate values are greater than or
equal to this value, therefore the total number of runoff records of the rainfall record is entered here. The
7
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Excel Engineering
final column which is the percent of time exceeded is calculated by dividing the total periods exceeded by
the total number of periods in the study. For the first row this number should be 100%
For the next row (row 2), the flow rate, and the flow rate count are entered. The total number of periods
exceeding for row 2 is calculated by subtracting Number of Periods of row 1 from the Total Periods
Exceeding of line 1. This result is entered in the Total Periods Exceeding on row 2. As was the case for
line 1, the final column is calculated by dividing the total periods exceeded by the total number of periods
in the study. For the second row this number should be something less than 100% and continually
decrease as we move down the chart. If all the calculations are correct, then everything should zero out
on the last line of the calculations.
The final step in developing the flow duration curves is to make a plot of the Discharge Rate vs. the
Percent Time Exceeded. For the purposes of this report, the first value corresponding to the zero flow
rate is not plotted allowing the graph to be focused on the actual flow rate values.
The Flow Duration Analysis
The Flow Duration analysis is composed of the following series of files:
1. The Flow Duration Plot
2. Comparison of the Post-Development Flow Duration Curve to the Pre-Development Curve
(Pass/Fail)
3. The calculations for the Pre-Development flow duration curve development (USGS9217d)
4. The calculations for the Post-Development flow duration curve development (USGS9217d)
The Flow Duration Plot
The Flow Duration Curves Plot is the plotting of both the pre-development and post-development sets of
Discharge Rate vs. the Percent Time Exceeded data point pair lists. Only that portion of the flow range
within the geomorphically significant range (Q10 – Qlf) is summarized. With these curves one can see a
visual representation of the relative positions of the respective flow duration curves. The flow duration
curves are compared in an East/West (horizontal) direction to compare post development Discharge
Rates to pre-development Discharge Rates. The pre-development curve is plotted in blue, and the post-
development curve is plotted in green. As long as the post development curve lies to the left of the pre-
development curve (mostly3), the project meets the peak flow hydromodification requirements.
Pass/Fail comparison of the curves
The next two sets of data are the point by point comparison of the post-development curve and the pre-
development curve. The Pass/Fail table is helpful in determining compliance since the plotted lines can
be difficult to see at the scales suitable for use in a report. Each point on the post- development curve
has a corresponding “Y” value (Flow Rate), and “X” value (% Time Exceeded). For each point on the
post development curve, the “Y” value is used to interpolate the corresponding Percent Time Exceeded
3 See hydromodification limits for exceedance of pre-development values
Excel Engineering
(X) value from the pre-development curve. Then the Post-Development Percent Time Exceeded value is
compared to the Pre-Development Percent Time Exceeded value. Based on the relative values of each
point, pass/fail criteria are determined point by point.
For each set of data, the upper right hand header value shows the name of the file being displayed (ex.
flowDurationPassFailMitigated.TXT). The first line of the file shows the name of the SWMM output file
(*.out). The next line shows the time stamp of the SWMM file that is being analyzed. The time stamps of
all of the report files should be within a minute or two of each other, otherwise there may have been
confusion with the files. Each report run creates and prints all of the files and reports at one time so all
the time stamps should be very close.
The first column is the zero based number of the point. The next two columns show the post
development “X” and “Y” values. The next column shows the value interpolated between the two
bounding points on the pre-development curve. The next three columns show the true or false values of
the comparison of the two “X” values. The last column shows the resultant pass or fail status of the point.
There are three ways a point can pass. They are:
1. Qpost being outside of the geomorphically significant range Qlf to Q10
2. Qpost being less than Q pre
3. Qpost being less than 110% of the value of Qpre if the point is between Qlf and Q10
There are two ways that a point can fail. They are:
1. Qpost being greater than 110% of Qpre if the point is between Qlf and Q10
2. If more than 10% of the points are between 100% and 110% of Qpre for the points between Qlf
and Q10
A quick scan down the last column will quickly tell if there are any points that fail.
At the bottom of each set of data are the date stamp of the report to the left, and to the right is the page
number/number of pages for the specific set of data (not the pages of the report!). Each new set of data
has its own page numbering. Between the file name in the header row and the page numbering in the
footer row, the engineer can readily scan the document for the data of interest.
Excel Engineering
Excel Engineering
flowDurationPassFailMitigated.TXT
Compared to:
pre-development SWMM file: V:\22\22081\Engineering\GPIP\Storm\Working Files\Hydmod\Current\22-081 PRE-DEV.out
pre-development time stamp: 5/15/2023 1:39:32 PM
Compare Post-Development Curve to Pre-Development Curve
Flow Control Upper Limit: 1.5627 (cfs)
Flow Control Lower Limit: 0.09940 (cfs)
post-development SWMM file: V:\22\22081\Engineering\GPIP\Storm\Working Files\Hydmod\Current\22081 POST-PC1 - Copy.out
post-development time stamp: 6/3/2025 6:29:35 PMPost PT #Flow Rate (cfs)Post Dev % ExceedPre Dev % Exceed%Ex post < %Ex pre%Ex post > %Ex pre%Ex post > 110% %Ex prePass/Fail0 0.10 0.03 0.08 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
1 0.11 0.03 0.08 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
2 0.13 0.02 0.07 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
3 0.14 0.02 0.07 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
4 0.16 0.02 0.07 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
5 0.17 0.02 0.06 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
6 0.19 0.02 0.06 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
7 0.20 0.01 0.06 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
8 0.22 0.01 0.05 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
9 0.23 0.01 0.05 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
10 0.25 0.01 0.05 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
11 0.26 0.01 0.05 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
12 0.28 0.01 0.04 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
13 0.29 0.01 0.04 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
14 0.31 0.01 0.04 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
15 0.32 0.01 0.04 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
16 0.34 0.01 0.04 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
17 0.35 0.01 0.04 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
18 0.37 0.01 0.03 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
19 0.38 0.01 0.03 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
20 0.40 0.01 0.03 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
21 0.41 0.01 0.03 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
22 0.42 0.01 0.03 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
23 0.44 0.00 0.03 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
24 0.45 0.00 0.02 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
25 0.47 0.00 0.02 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
1/46/4/2025 11:02 AM
Excel Engineering
flowDurationPassFailMitigated.TXTPost PT #Flow Rate (cfs)Post Dev % ExceedPre Dev % Exceed%Ex post < %Ex pre%Ex post > %Ex pre%Ex post > 110% %Ex prePass/Fail26 0.48 0.00 0.02 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
27 0.50 0.00 0.02 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
28 0.51 0.00 0.02 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
29 0.53 0.00 0.02 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
30 0.54 0.00 0.02 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
31 0.56 0.00 0.02 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
32 0.57 0.00 0.02 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
33 0.59 0.00 0.02 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
34 0.60 0.00 0.01 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
35 0.62 0.00 0.01 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
36 0.63 0.00 0.01 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
37 0.65 0.00 0.01 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
38 0.66 0.00 0.01 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
39 0.68 0.00 0.01 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
40 0.69 0.00 0.01 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
41 0.71 0.00 0.01 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
42 0.72 0.00 0.01 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
43 0.74 0.00 0.01 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
44 0.75 0.00 0.01 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
45 0.76 0.00 0.01 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
46 0.78 0.00 0.01 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
47 0.79 0.00 0.01 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
48 0.81 0.00 0.01 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
49 0.82 0.00 0.01 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
50 0.84 0.00 0.01 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
51 0.85 0.00 0.01 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
52 0.87 0.00 0.01 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
53 0.88 0.00 0.01 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
54 0.90 0.00 0.01 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
55 0.91 0.00 0.01 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
56 0.93 0.00 0.01 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
57 0.94 0.00 0.01 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
58 0.96 0.00 0.01 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
59 0.97 0.00 0.01 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
60 0.99 0.00 0.01 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
61 1.00 0.00 0.01 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
2/46/4/2025 11:02 AM
Excel Engineering
flowDurationPassFailMitigated.TXTPost PT #Flow Rate (cfs)Post Dev % ExceedPre Dev % Exceed%Ex post < %Ex pre%Ex post > %Ex pre%Ex post > 110% %Ex prePass/Fail62 1.02 0.00 0.01 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
63 1.03 0.00 0.00 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
64 1.05 0.00 0.00 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
65 1.06 0.00 0.00 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
66 1.07 0.00 0.00 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
67 1.09 0.00 0.00 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
68 1.10 0.00 0.00 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
69 1.12 0.00 0.00 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
70 1.13 0.00 0.00 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
71 1.15 0.00 0.00 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
72 1.16 0.00 0.00 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
73 1.18 0.00 0.00 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
74 1.19 0.00 0.00 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
75 1.21 0.00 0.00 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
76 1.22 0.00 0.00 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
77 1.24 0.00 0.00 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
78 1.25 0.00 0.00 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
79 1.27 0.00 0.00 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
80 1.28 0.00 0.00 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
81 1.30 0.00 0.00 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
82 1.31 0.00 0.00 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
83 1.33 0.00 0.00 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
84 1.34 0.00 0.00 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
85 1.36 0.00 0.00 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
86 1.37 0.00 0.00 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
87 1.39 0.00 0.00 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
88 1.40 0.00 0.00 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
89 1.41 0.00 0.00 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
90 1.43 0.00 0.00 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
91 1.44 0.00 0.00 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
92 1.46 0.00 0.00 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
93 1.47 0.00 0.00 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
94 1.49 0.00 0.00 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
95 1.50 0.00 0.00 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
96 1.52 0.00 0.00 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
97 1.53 0.00 0.00 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
3/46/4/2025 11:02 AM
Excel Engineering
flowDurationPassFailMitigated.TXTPost PT #Flow Rate (cfs)Post Dev % ExceedPre Dev % Exceed%Ex post < %Ex pre%Ex post > %Ex pre%Ex post > 110% %Ex prePass/Fail98 1.55 0.00 0.00 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
99 1.56 0.00 0.00 TRUE FALSE FALSE Pass: Post Duration <= Pre Duration
4/46/4/2025 11:02 AM
Excel Engineering
USGS9217dPre.csv
DISCHARGE Number of periods when discharge was equal to or greater than DISCHARGE
column but less than that shown on the next line
Duration Table Summary at Project Discharge Point
file name: V:\22\22081\Engineering\GPIP\Storm\Working Files\Hydmod\Current\22-081 PRE-DEV.out
time stamp: 5/15/2023 1:39:32 PMBin NumberDischarge Rate (cfs)Number of PeriodsTotal Periods ExceedingPercent Time Exceeded1 0.0994 19 410 0.082
2 0.1142 14 391 0.078
3 0.1290 19 377 0.075
4 0.1437 19 358 0.071
5 0.1585 24 339 0.067
6 0.1733 15 315 0.063
7 0.1881 10 300 0.060
8 0.2029 15 290 0.058
9 0.2176 14 275 0.055
10 0.2324 22 261 0.052
11 0.2472 8 239 0.048
12 0.2620 9 231 0.046
13 0.2768 4 222 0.044
14 0.2916 6 218 0.043
15 0.3063 10 212 0.042
16 0.3211 14 202 0.040
17 0.3359 8 188 0.037
18 0.3507 6 180 0.036
19 0.3655 8 174 0.035
20 0.3802 6 166 0.033
21 0.3950 7 160 0.032
22 0.4098 16 153 0.030
23 0.4246 11 137 0.027
24 0.4394 7 126 0.025
25 0.4541 6 119 0.024
26 0.4689 6 113 0.022
27 0.4837 5 107 0.021
28 0.4985 4 102 0.020
29 0.5133 5 98 0.019
30 0.5280 3 93 0.018
31 0.5428 4 90 0.018
32 0.5576 4 86 0.017
33 0.5724 4 82 0.016
34 0.5872 4 78 0.016
35 0.6019 4 74 0.015
36 0.6167 3 70 0.014
37 0.6315 7 67 0.013
38 0.6463 4 60 0.012
39 0.6611 2 56 0.011
40 0.6759 3 54 0.011
41 0.6906 1 51 0.010
42 0.7054 2 50 0.010
43 0.7202 3 48 0.010
44 0.7350 2 45 0.009
45 0.7498 1 43 0.009
1/36/4/2025 11:02 AM
Excel Engineering
USGS9217dPre.csvBin NumberDischarge Rate (cfs)Number of PeriodsTotal Periods ExceedingPercent Time Exceeded46 0.7645 1 42 0.008
47 0.7793 1 41 0.008
48 0.7941 1 40 0.008
49 0.8089 2 39 0.008
50 0.8237 3 37 0.007
51 0.8384 1 34 0.007
52 0.8532 0 33 0.007
53 0.8680 1 33 0.007
54 0.8828 1 32 0.006
55 0.8976 1 31 0.006
56 0.9123 0 30 0.006
57 0.9271 1 30 0.006
58 0.9419 0 29 0.006
59 0.9567 0 29 0.006
60 0.9715 1 29 0.006
61 0.9862 2 28 0.006
62 1.0010 0 26 0.005
63 1.0158 3 26 0.005
64 1.0306 1 23 0.005
65 1.0454 1 22 0.004
66 1.0602 2 21 0.004
67 1.0749 2 19 0.004
68 1.0897 0 17 0.003
69 1.1045 0 17 0.003
70 1.1193 0 17 0.003
71 1.1341 1 17 0.003
72 1.1488 1 16 0.003
73 1.1636 0 15 0.003
74 1.1784 4 15 0.003
75 1.1932 1 11 0.002
76 1.2080 0 10 0.002
77 1.2227 1 10 0.002
78 1.2375 1 9 0.002
79 1.2523 1 8 0.002
80 1.2671 1 7 0.001
81 1.2819 1 6 0.001
82 1.2966 0 5 0.001
83 1.3114 0 5 0.001
84 1.3262 1 5 0.001
85 1.3410 0 4 0.001
86 1.3558 0 4 0.001
87 1.3705 1 4 0.001
88 1.3853 1 3 0.001
89 1.4001 0 2 0.000
90 1.4149 0 2 0.000
91 1.4297 0 2 0.000
92 1.4445 1 2 0.000
93 1.4592 0 1 0.000
94 1.4740 0 1 0.000
95 1.4888 0 1 0.000
96 1.5036 0 1 0.000
97 1.5184 1 1 0.000
98 1.5331 0 0 0.000
99 1.5479 0 0 0.000
2/36/4/2025 11:02 AM
Excel Engineering
USGS9217dPre.csvBin NumberDischarge Rate (cfs)Number of PeriodsTotal Periods ExceedingPercent Time Exceeded100 1.5627 0 0 0.000
-------------End of Data-----------------
3/36/4/2025 11:02 AM
Excel Engineering
USGS9217dPostMitigated.csv
DISCHARGE Number of periods when discharge was equal to or greater than DISCHARGE
column but less than that shown on the next line
Duration Table Summary at Project Discharge Point
file name: V:\22\22081\Engineering\GPIP\Storm\Working Files\Hydmod\Current\22081 POST-PC1 - Copy.out
time stamp: 6/3/2025 6:29:35 PMBin NumberDischarge Rate (cfs)Number of PeriodsTotal Periods ExceedingPercent Time Exceeded1 0.0994 45 173 0.034
2 0.1142 23 128 0.025
3 0.1290 8 105 0.021
4 0.1437 7 97 0.019
5 0.1585 8 90 0.018
6 0.1733 5 82 0.016
7 0.1881 6 77 0.015
8 0.2029 8 71 0.014
9 0.2176 9 63 0.013
10 0.2324 6 54 0.011
11 0.2472 2 48 0.010
12 0.2620 1 46 0.009
13 0.2768 2 45 0.009
14 0.2916 4 43 0.009
15 0.3063 3 39 0.008
16 0.3211 3 36 0.007
17 0.3359 2 33 0.007
18 0.3507 2 31 0.006
19 0.3655 1 29 0.006
20 0.3802 0 28 0.006
21 0.3950 1 28 0.006
22 0.4098 2 27 0.005
23 0.4246 3 25 0.005
24 0.4394 3 22 0.004
25 0.4541 0 19 0.004
26 0.4689 1 19 0.004
27 0.4837 0 18 0.004
28 0.4985 0 18 0.004
29 0.5133 0 18 0.004
30 0.5280 1 18 0.004
31 0.5428 0 17 0.003
32 0.5576 0 17 0.003
33 0.5724 0 17 0.003
34 0.5872 2 17 0.003
35 0.6019 1 15 0.003
36 0.6167 0 14 0.003
37 0.6315 1 14 0.003
38 0.6463 2 13 0.003
39 0.6611 1 11 0.002
40 0.6759 0 10 0.002
41 0.6906 0 10 0.002
42 0.7054 0 10 0.002
43 0.7202 0 10 0.002
44 0.7350 0 10 0.002
45 0.7498 0 10 0.002
1/36/4/2025 11:02 AM
Excel Engineering
USGS9217dPostMitigated.csvBin NumberDischarge Rate (cfs)Number of PeriodsTotal Periods ExceedingPercent Time Exceeded46 0.7645 2 10 0.002
47 0.7793 0 8 0.002
48 0.7941 0 8 0.002
49 0.8089 0 8 0.002
50 0.8237 1 8 0.002
51 0.8384 0 7 0.001
52 0.8532 0 7 0.001
53 0.8680 0 7 0.001
54 0.8828 1 7 0.001
55 0.8976 0 6 0.001
56 0.9123 1 6 0.001
57 0.9271 0 5 0.001
58 0.9419 0 5 0.001
59 0.9567 0 5 0.001
60 0.9715 1 5 0.001
61 0.9862 0 4 0.001
62 1.0010 0 4 0.001
63 1.0158 0 4 0.001
64 1.0306 0 4 0.001
65 1.0454 0 4 0.001
66 1.0602 0 4 0.001
67 1.0749 0 4 0.001
68 1.0897 0 4 0.001
69 1.1045 0 4 0.001
70 1.1193 1 4 0.001
71 1.1341 0 3 0.001
72 1.1488 0 3 0.001
73 1.1636 1 3 0.001
74 1.1784 0 2 0.000
75 1.1932 0 2 0.000
76 1.2080 1 2 0.000
77 1.2227 0 1 0.000
78 1.2375 0 1 0.000
79 1.2523 0 1 0.000
80 1.2671 0 1 0.000
81 1.2819 0 1 0.000
82 1.2966 0 1 0.000
83 1.3114 0 1 0.000
84 1.3262 0 1 0.000
85 1.3410 0 1 0.000
86 1.3558 0 1 0.000
87 1.3705 0 1 0.000
88 1.3853 0 1 0.000
89 1.4001 0 1 0.000
90 1.4149 0 1 0.000
91 1.4297 0 1 0.000
92 1.4445 0 1 0.000
93 1.4592 0 1 0.000
94 1.4740 0 1 0.000
95 1.4888 1 1 0.000
96 1.5036 0 0 0.000
97 1.5184 0 0 0.000
98 1.5331 0 0 0.000
99 1.5479 0 0 0.000
2/36/4/2025 11:02 AM
Excel Engineering
USGS9217dPostMitigated.csvBin NumberDischarge Rate (cfs)Number of PeriodsTotal Periods ExceedingPercent Time Exceeded100 1.5627 0 0 0.000
-------------End of Data-----------------
3/36/4/2025 11:02 AM
EPA STORM WATER MANAGEMENT MODEL - VERSION 5.1 (Build 5.1.015)
--------------------------------------------------------------
PRE-DEVELOPMENT
*********************************************************
NOTE: The summary statistics displayed in this report are
based on results found at every computational time step,
not just on results from each reporting time step.
*********************************************************
****************
Analysis Options
****************
Flow Units ............... CFS
Process Models:
Rainfall/Runoff ........ YES
RDII ................... NO
Snowmelt ............... NO
Groundwater ............ NO
Flow Routing ........... NO
Water Quality .......... NO
Infiltration Method ...... GREEN_AMPT
Starting Date ............ 01/03/1951 16:00:00
Ending Date .............. 05/23/2008 23:00:00
Antecedent Dry Days ...... 0.0
Report Time Step ......... 01:00:00
Wet Time Step ............ 00:30:00
Dry Time Step ............ 01:00:00
************************** Volume Depth
Runoff Quantity Continuity acre-feet inches
************************** --------- -------
Total Precipitation ...... 115.251 675.090
Evaporation Loss ......... 2.190 12.828
Infiltration Loss ........ 103.323 605.221
Surface Runoff ........... 12.739 74.622
Final Storage ............ 0.000 0.000
Continuity Error (%) ..... -2.604
************************** Volume Volume
Flow Routing Continuity acre-feet 10^6 gal
************************** --------- ---------
Dry Weather Inflow ....... 0.000 0.000
Wet Weather Inflow ....... 12.739 4.151
Groundwater Inflow ....... 0.000 0.000
RDII Inflow .............. 0.000 0.000
External Inflow .......... 0.000 0.000
External Outflow ......... 12.739 4.151
Flooding Loss ............ 0.000 0.000
Evaporation Loss ......... 0.000 0.000
Exfiltration Loss ........ 0.000 0.000
Initial Stored Volume .... 0.000 0.000
Final Stored Volume ...... 0.000 0.000
Continuity Error (%) ..... 0.000
***************************
Subcatchment Runoff Summary
***************************
Total Total Total Total Imperv Perv Total Total Peak Runoff
Precip Runon Evap Infil Runoff Runoff Runoff Runoff Runoff Coeff
Subcatchment in in in in in in in 10^6 gal CFS
BASIN-1 675.09 0 12.91 605.69 0 73.56 73.56 1.98 1.12 0.109
BASIN-2 675.09 0 12.85 605.31 0 74.43 74.43 1.69 0.94 0.11
BASIN-3 675.09 0 12.37 602.78 0 80.09 80.09 0.48 0.25 0.119
Analysis begun on: Mon May 15 13:34:48 2023
Analysis ended on: Mon May 15 13:39:32 2023
Total elapsed time: 00:04:44
1
2 EPA STORM WATER MANAGEMENT MODEL - VERSION 5.2 (Build 5.2.0)
3 ------------------------------------------------------------
4
5
6 ****************
7 Analysis Options
8 ****************
9 Flow Units ............... CFS
10 Process Models:
11 Rainfall/Runoff ........ YES
12 RDII ................... NO
13 Snowmelt ............... NO
14 Groundwater ............ NO
15 Flow Routing ........... NO
16 Water Quality .......... NO
17 Infiltration Method ...... GREEN_AMPT
18 Starting Date ............ 01/03/1951 16:00:00
19 Ending Date .............. 05/23/2008 23:00:00
20 Antecedent Dry Days ...... 0.0
21 Report Time Step ......... 01:00:00
22 Wet Time Step ............ 00:05:00
23 Dry Time Step ............ 00:00:00
24
25
26 ************************** Volume Depth
27 Runoff Quantity Continuity acre-feet inches
28 ************************** --------- -------
29 Initial LID Storage ...... 0.015 0.086
30 Total Precipitation ...... 115.517 675.090
31 Evaporation Loss ......... 22.207 129.779
32 Infiltration Loss ........ 17.552 102.573
33 Surface Runoff ........... 2.323 13.577
34 LID Drainage ............. 42.525 248.521
35 Final Storage ............ 31.117 181.851
36 Continuity Error (%) ..... -0.167
37
38
39 ************************** Volume Volume
40 Flow Routing Continuity acre-feet 10^6 gal
41 ************************** --------- ---------
42 Dry Weather Inflow ....... 0.000 0.000
43 Wet Weather Inflow ....... 44.848 14.615
44 Groundwater Inflow ....... 0.000 0.000
45 RDII Inflow .............. 0.000 0.000
46 External Inflow .......... 0.000 0.000
47 External Outflow ......... 44.848 14.615
48 Flooding Loss ............ 0.000 0.000
49 Evaporation Loss ......... 0.000 0.000
50 Exfiltration Loss ........ 0.000 0.000
51 Initial Stored Volume .... 0.000 0.000
52 Final Stored Volume ...... 0.000 0.000
53 Continuity Error (%) ..... 0.000
54
55
56 ***************************
57 Subcatchment Runoff Summary
58 ***************************
59
60
---------------------------------------------------------------------------------------------------------------------
---------
61 Total Total Total Total Imperv Perv Total Total
Peak Runoff
62 Precip Runon Evap Infil Runoff Runoff Runoff Runoff
Runoff Coeff
63 Subcatchment in in in in in in in 10^6 gal
CFS
64
---------------------------------------------------------------------------------------------------------------------
---------
65 DMA-1 675.09 0.00 90.88 109.23 465.04 11.19 476.23 1.47
0.14 0.705
66 BMP-A 675.09 16482.69 1089.86 0.00 0.00 0.00 16070.55 1.43
0.14 0.937
67 DMA-2 675.09 0.00 81.22 164.17 414.52 16.42 430.94 1.65
0.17 0.638
68 BMP-B 675.09 5320.63 954.45 0.00 0.00 0.00 5041.18 1.56
0.18 0.841
69 BMP-E 675.09 7059.42 980.34 0.00 0.00 0.00 6754.11 2.14
0.24 0.873
70 DMA-7 675.09 0.00 104.59 0.00 574.02 0.00 574.02 0.12
0.01 0.850
71 DMA-5 675.09 0.00 85.64 152.69 423.12 14.48 437.60 2.24
0.22 0.648
72 DMA-4 675.09 0.00 94.07 97.19 475.04 9.84 484.88 7.08
0.64 0.718
73 BMP-D 675.09 8046.33 1000.71 0.00 0.00 0.00 7721.34 6.79
0.68 0.885
74 DMA-3 675.09 0.00 99.84 66.62 502.68 6.96 509.64 10.49
0.91 0.755
75 BMP-C 675.09 12605.26 539.88 431.48 0.00 0.00 138.56 0.12
0.01 0.010
76 DMA-6 675.09 0.00 82.92 145.34 433.32 15.25 448.57 2.54
0.25 0.664
77 BMP-F 675.09 10483.35 1044.21 0.00 0.00 0.00 10114.34 2.45
0.26 0.906
78
79
80 ***********************
81 LID Performance Summary
82 ***********************
83
84 --------------------------------------------------------------------------------------------------------------------
85 Total Evap Infil Surface Drain Initial Final Continuity
86 Inflow Loss Loss Outflow Outflow Storage Storage Error
87 Subcatchment LID Control in in in in in in in %
88 --------------------------------------------------------------------------------------------------------------------
89 BMP-A BMP-A 17157.78 1089.89 0.00 1209.66 14861.34 1.80 2.50 -0.02
90 BMP-B BMP-B 5995.72 954.48 0.00 40.65 5000.72 1.80 2.08 -0.01
91 BMP-E BMP-E 7734.51 980.37 0.00 253.63 6500.73 1.80 2.12 -0.01
92 BMP-D BMP-D 8721.42 1000.68 0.00 320.95 7400.17 1.80 2.17 -0.01
93 BMP-C BMP-C 675.09 536.29 0.00 0.00 138.72 1.80 1.88 0.00
94 BMP-F BMP-F 11158.44 1044.25 0.00 638.66 9476.07 1.80 2.31 -0.01
95
96 Analysis begun on: Thu Jun 5 10:03:08 2025
97 Analysis ended on: Thu Jun 5 10:09:54 2025
98 Total elapsed time: 00:06:46
Total Total Total Total Imperv Perv Total Total Peak Runoff
Precip Runon Evap Infil Runoff Runoff Runoff Runoff Runoff Coeff
Subcatchment in in in in in in in 10^6 gal CFS
DMA-1 675.09 0 88.26 109.48 483.73 12.6 496.34 1.53 0.14 0.735
BMP-A 675.09 17178.4 1152.57 0 0 0 16722.15 1.49 0.14 0.937
DMA-2 675.09 0 78.87 164.46 431.17 18.32 449.5 1.72 0.17 0.666
BMP-B 675.09 5549.69 1004.95 0 0 0 5221.38 1.62 0.17 0.839
BMP-E 675.09 7345.57 1032.9 0 0 0 6989.63 2.21 0.23 0.871
DMA-7 675.09 0 100.9 0 596.17 0 596.17 0.12 0.01 0.883
DMA-5 675.09 0 83.36 152.95 439.58 15.76 455.34 2.33 0.22 0.674
DMA-4 675.09 0 91.49 97.4 493.98 11.01 505 7.37 0.64 0.748
BMP-D 675.09 8380.03 1054.31 0 0 0 8004.53 7.04 0.65 0.884
DMA-3 675.09 0 97.14 66.87 522.48 7.77 530.25 10.92 0.91 0.785
BMP-C 675.09 13114.96 1115.7 0 0 0 12680.15 10.56 0.94 0.92
DMA-6 675.09 0 80.32 145.74 450.51 17.31 467.82 2.65 0.25 0.693
BMP-F 675.09 10933.2 1101.6 0 0 0 10511.44 2.55 0.26 0.906
------------------------------------------------------------------------------------------------------------------------------
Analysis begun on: Mon May 15 13:42:55 2023
Analysis ended on: Mon May 15 13:48:08 2023
Total elapsed time: 00:05:13
Tota l Evap lnfil Surface Drain Initial Final Continuity
Inflow Loss Loss Outflow Outflow Storage Storage Error
LID Control in in in in in in in %
BMP-A 17853.49 1152.6 0 1356.19 15366.43 2.1 2.86 -0.13
BMP-B 6224.78 1004.99 0 55.47 5166.11 2.1 2.39 -0.03
BMP·E 8020.66 1032.94 0 375.51 6614.37 2.1 2.43 -0.03
BMP-D 905S.12 1054,35 0 3S6.33 7648.49 2.1 2.49 -0.05
BMP-C 13790.05 1115.74 0 1928.24 10752.37 2.1 2.66 -0.05
BMP·F 11608.29 1.101,64 0 1086.32 9425.52 2.1 2.63 ·0.05
Excel Engineering
SWMM C Factor and Drawdown Results
Underdrain and Drawdown Results
The following table summarizes the underdrain coefficients used for each of the BMP units and translates
the C factor coefficient to an equivalent round orifice diameter based on 1/16th inch increments. The
drawdown equations are based on standard falling head drawdown theory. The primary drawdown number of
interest is the surface drawdown based on vector concerns. The various soil and gravel storage layer
calculations consider the void ratio and porosity of the respective layer. It should be noted that these
drawdown calculations only consider the volume of water within the bioretention units. If the bioretention
unit utilizes any storage above the berm height, then that storage drawdown is in addition to the values
shown in the table below. Those calculations, if present, are shown elsewhere in the report. The
derivation and explanation of the equations used to determine the values displayed in the chart are
discussed in the following two sections of this portion of the report.
Su
b
C
a
t
Na
m
e
*
LI
D
Pr
o
c
e
s
s
*
LI
D
A
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DMA-1 BMP-A 141 8 0.59036 6 21 27 0.4 0.67 1.4 2.3 7.1 10.8
DMA-2 BMP-B 498 8 0.16714 6 21 27 0.4 0.67 5.0 8.3 24.9 38.3
DMA-3 BMP-C 1336 12 0.14018 6 21 21 0.4 0.67 6.4 10.8 26.2 43.4
DMA-4 BMP-D 1411 12 0.13273 6 21 27 0.4 0.67 6.3 10.4 31.4 48.2
DMA-5 BMP-E 508 8 0.16386 6 21 15 0.4 0.67 5.9 10.4 19.0 35.2
DMA-6 BMP-F 389 8 0.21399 6 21 15 0.4 0.67 4.5 8.0 14.5 27.0
The character * in the column heading indicates that the values was read directly from the SWMM inp file.
Assume: orifice coefficient Co = 0.61, void ratio for surface = 1.0, centroid of underdrain orifice is located at h=0
Excel Engineering
inp File Listing
Underdrain C Factor Equations
Based on the slotted drain example in the SWMM Drain Advisor (EPA SWMM 5.1
Help/Contents/Reference/Special Dialog Forms/LID Editors/LID Control
Editor/LID Drain System/Drain Advisor) the underdrain coefficient C is the
ratio of the orifice area (total slot area) to the LID area times a constant
(60,000).
SWMM Ex: If the drain consists of slotted pipes where the slots act as
orifices, then the drain exponent would be 0.5 and the drain coefficient
would be 60,000 times the ratio of total slot area to LID area. For example,
drain pipe with five 1/4" diameter holes per foot spaced 50 feet apart would
have an area ratio of 0.000035 and a drain coefficient of 2.
The 60,000 constant in the above example corresponds to the combined
constants in the standard orifice equation:
(Standard Orifice Equation)
q=CoAo√2𝑔 √ℎ (cfs)
and
(SWMM Underdrain Equation (per unit area))
q=q/ALID
or
q=CoAo/ALID√2𝑔 √ℎ (cfs/sf)
With a Co=0.6 and converting √2𝑔 to units of inches and hours the constant
becomes 60,046.
So the underdrain C factor per unit area of the LID becomes:
C=60,046 Ao/ALID (in^1/2/hr)
and
q=C*h1/2
Excel Engineering
inp File Listing
Drawdown Equations
The drawdown equations presented in the chart are the drawdown times for the
respective layers within the bioretention unit (only). If the bioretention
unit includes storage ponding above the berm height, then the drawdown time
for the storage portion is in addition to the values shown in the chart.
Those calculations (if present) are shown elsewhere in the report. For most
cases the storage drawdown time will be comparatively short as compared to
the bioretention drawdown times.
To derive a general formula that relates drawdown time for each layer of the
bioretention unit in terms of the SWMM C factor, we set the change in water
volume with respect to time equal to the standard orifice equation (found in
the County Hydraulics manual):
𝑛= 𝑑ℎ
𝑑𝑡 𝑛𝐴𝑛=𝐶𝑛𝐴𝑛√2𝑔ℎ
Where n = porosity of the layer, AP = area of the BMP unit, Co = orifice
coefficient, Ao = area of the orifice, and g = gravity constant. The
porosity n for the surface layer is 1.0, and the values for the soil and
storage layers read from the SWMM LID definitions.
Solving the definite integral from h1 to h2
∫ℎ−0.5𝑑ℎ
ℎ=ℎ2
ℎ=ℎ1
=∫𝐶𝑛𝐴𝑛√2𝑔
𝑛𝐴𝑛
𝑡=𝑇
𝑡=0
𝑑𝑡
2(√ℎ2 −√ℎ1)=𝐶𝑛𝐴𝑛√2𝑔
𝑛𝐴𝑛 (𝑇)
Or
2𝑛(√ℎ2 −√ℎ1)=𝐶 (𝑇)
𝑤ℎ𝑑𝑛𝑑: 𝐶=𝐶𝑛𝐴𝑛√2𝑔
𝐴𝑛 (in^1/2/hr)
Solving for T:
𝑇=2𝑛(√ℎ2−√ℎ1)
𝐶 (hr)
Where h2(in) is the total beginning head above the underdrain orifice at t=0
and h1(in) is the total ending head above the orifice at t=T. Ex: h2 for
surface = depth of gravel storage plus depth of soil layer plus berm height,
and h1 for surface = depth of gravel storage plus depth of soil layer.
ATTACHMENT 3
Structural BMP Maintenance Information
Use this checklist to ensure the required information has been included in the Structural
BMP Maintenance Information Attachment:
Preliminary Design/Planning/CEQA level submittal:
Attachment 3 must identify:
Typical maintenance indicators and actions for proposed structural BMP(s) based
on Section 7.7 of the BMP Design Manual
Final Design level submittal:
Attachment 3 must identify:
Specific maintenance indicators and actions for proposed structural BMP(s). This
shall be based on Section 7.7 of the BMP Design Manual and enhanced to reflect
actual proposed components of the structural BMP(s)
How to access the structural BMP(s) to inspect and perform maintenance
Features that are provided to facilitate inspection (e.g., observation ports,
cleanouts, silt posts, or other features that allow the inspector to view necessary
components of the structural BMP and compare to maintenance thresholds)
Manufacturer and part number for proprietary parts of structural BMP(s) when
applicable
Maintenance thresholds for BMPs subject to siltation or heavy trash(e.g., silt level
posts or other markings shall be included in all BMP components that will trap and
store sediment, trash, and/or debris, so that the inspector may determine how full
the BMP is, and the maintenance personnel may determine where the bottom of
the BMP is . If required, posts or other markings shall be indicated and described
on structural BMP plans.)
Recommended equipment to perform maintenance
When applicable, necessary special training or certification requirements for
inspection and maintenance personnel such as confined space entry or
hazardous waste management
__,
OPERATION & MAINTENANCE (O&M) PLAN
Contents
1. PROJECT DESCRIPTION .................................................................................................. 1
2. OPERATION & MAINTENANCE PLAN ......................................................................... 1
3. Operation & Maintenance of BMP’S .................................................................................. 1
A. Training .............................................................................................................. 2
B. Landscaping ....................................................................................................... 2
C. Irrigation System ................................................................................................ 5
D. Trash Storage Areas .......................................................................................... 5
E. Storm Water Conveyance System Stenciling and Signing ................................. 5
F. Biofiltration ......................................................................................................... 6
G. Outlet Structures ................................................................................................ 8
H. Vector Management Control Requirements ..................................................... 10
ATTACHMENTS
A. O&M Exhibit
A1. Inspection & Maintenance Schedule
B1. Cost Estimate
C1. BMP Training Log
D1. Inspection & Maintenance Log
E1. Maintenance Indicators (Table 7-2)
-i-
1
1. PROJECT DESCRIPTION
The purpose of the project is to build a medical office building with associated parking and site
amenities including landscaping and several bioretention facilities (Biofiltration).
2. OPERATION & MAINTENANCE PLAN
The Operation and Maintenance Plan (O&M) needs to address construction and post-construction
concerns as shown in the Storm Water Mitigation Plan.
3. Operation & Maintenance of BMP’S
It shall be the responsibility of the owner to train all employees for the maintenance and operation of
all BMPs, to achieve the maximum pollutant reduction, as addressed in the approved Project’s
SWQMP. The following schedule of (O&M’s) must be followed to satisfy the Conditions of Concern
and the Pollutants of Concern as addressed in the approved Project’s SWQMP and the City’s BMP
manual. This schedule shall include periodic inspections of all Source Control and Treatment Control
BMP’s. All maintenance records for training, inspection and maintenance shall be retained and
provided to the city upon request.
All BMPs shall be inspected 30 days prior to October lst each year and certified to the City
Engineering Department as to their readiness to receive runoff from the annual rainfall season.
The owner will also provide to the City, as part of the maintenance and operation agreement, an
executed maintenance and access easement that shall be binding on the land throughout the life of the
project.
2
Responsible Party for O&M and For Training- Property Owner
North Coast Medical – Phase 1 and Phase 2
A. Training
Training of Operation and Maintenance personnel is of primary importance to provide knowledge of
the operation and maintenance of BMPs. Proper training shall provide information that will enable
employees to have in place an effective preventive maintenance program as described in this O & M
manual. The responsible party mentioned above should read the course provided by the San Diego
BMP Manual, to be trained in the purpose and use of BMPs and the maintenance thereof. Proper
preventive maintenance will prevent environmental incidents that may be a health and safety hazard.
New employees should be trained as to the purpose and proper maintenance within the first week of
their employment.
Employee training shall include receiving a copy of this O & M manual; a discussion on the location
and purpose of site specific BMPs, such as Source Control and Treatment Control BMPs; training on
how to inspect and report maintenance problems and to whom they report to; They shall be trained in
site specific Pollutants of Concern so that they can evaluate the functioning of all on-site BMPs .
These Pollutants are identified in section 2 of this report.
A log of all training and reported inspections and maintenance problems along with what was done to
correct the problem shall be kept on the premises at all times.
Employees shall be periodically trained, at a minimum of once a year, to refresh their abilities to
Operate and Maintain all on-site BMPs.
B. Landscaping
Operational and maintenance needs include:
▪ Vegetation management to maintain adequate hydraulic functioning and to limit habitat for
disease-carrying animals.
▪ Animal and vector control.
▪ Periodic sediment removal to optimize performance.
▪ Trash, debris, grass trimmings, tree pruning, dead vegetation collection and removal.
▪ Removal of standing water, which may contribute to the development of aquatic plant
communities or mosquito breeding areas.
▪ Erosion and structural maintenance to prevent the loss of soil and maintain the performance of
all landscaping.
3
Inspection Frequency
The facility will be inspected and inspection visits will be completely documented:
▪ Once a month at a minimum.
▪ After every large storm (after every storm monitored or these storms with more than 0.50 inch
of precipitation.)
▪ On a weekly basis during extended periods of wet weather.
Inspect for proper irrigation and fertilizer use, and ensure that all landscaped areas have minimum of
80% coverage.
Aesthetic Maintenance
The following activities will be included in the aesthetic maintenance program:
Grass Trimming: Trimming of grass will be done on all landscaped areas, around fences, at the inlet
and outlet structures, and sampling structures.
Weed Control. Weeds will be removed through mechanical means. Herbicide will not be used because
these chemicals may impact the water quality monitoring.
Functional Maintenance
Functional maintenance has two components:
▪ Preventive maintenance
▪ Corrective maintenance
Preventive Maintenance
Preventive maintenance activities to be instituted for landscaped areas are:
▪ Grass Mowing: Vegetation seed, mix within the landscaped areas, are to be designed to be
kept short to maintain adequate hydraulic functioning and to limit the development of faunal
habitats.
▪ Trash and Debris: During each inspection and maintenance visit to the site, debris and trash
removal will be conducted to reduce the potential for inlet and outlet structures and other
components from becoming clogged and inoperable during storm events.
▪ Sediment Removal: Sediment accumulation, as part of the operation and maintenance program
at of landscaped areas, will be monitored once a month during the dry season, after every large
storm (0.50 inch), and monthly during the wet season. Specifically, if sediment reaches a level
at or near plant height, or could interfere with flow or operation, the sediment shall be removed.
If accumulation of debris or sediment is determined to be the cause of decline in design
performance, prompt action (i.e., within ten working days) will be taken to restore the
landscaped areas to design performance standards. Actions will include using additional
vegetation and/or removing accumulated sediment to correct channeling or ponding.
Characterization and Appropriate disposal of sediment will comply with applicable local,
county, state, or federal requirements.
▪ Landscaped areas will be re-graded, if the flow gradient has been altered. This should be a sign
that the BMP is failing and the soil matrix may need to be replaced.
4
▪ Removal of Standing Water: Standing water must be removed if it contributes to the
development of aquatic plant communities or mosquito breeding areas.
▪ Fertilization and Irrigation: fertilization and irrigation is to be keep at a minimum.
▪ Elimination of Mosquito Breeding Habitats. The most effective mosquito control program is
one that eliminates standing water over a period less than 96 hours.
Corrective Maintenance
Corrective maintenance is required on an emergency or non-routine basis to correct problems and to
restore the intended operation and safe function of all landscaped areas.
Corrective maintenance activities include:
▪ Removal of Debris and Sediment: Sediment, debris, and trash, which impede the hydraulic
functioning of landscaping and prevent vegetative growth, will be removed and properly
disposed. Temporary arrangements will be made for handling the sediments until a permanent
arrangement is made. Vegetation will be re-established after sediment removal.
▪ Structural Repairs: Once deemed necessary, repairs to structural components of landscaping
will be done within l0 working days. Qualified individuals (i.e., the designers or contractors)
will conduct repairs where structural damage has occurred.
▪ Embankment and Slope Repairs: Once deemed necessary, damage to the embankments and
slopes of landscaped areas will be repaired within l0 working days.
▪ Erosion Repair: Where a reseeding program has been ineffective, or where other factors have
created erosive conditions (i.e., pedestrian traffic, concentrated flow, etc.), corrective steps
will be taken to prevent loss of soil and any subsequent danger to the performance and use of
landscaped areas as BMPs. There are a number of corrective actions than can be taken.
▪ These include erosion control blankets, riprap, or reducing flow velocity.
▪ Consult with an engineer and contractor to address frequently occurring erosion problems.
▪ Elimination of Animal Burrows: animal burrows will be filled and steps taken to remove the
animals if burrowing problems continue to occur (filling and compacting). If the problem
persists, vector control specialists will be consulted regarding removal steps. This consulting is
necessary as the threat of rabies in some areas may necessitate the animals being destroyed
rather than relocated. If the BMP performance is affected, abatement will begin. Otherwise,
abatement will be performed annually in September.
▪ General Facility Maintenance: In addition to the above elements of corrective maintenance,
general corrective maintenance will address the overall facility and its associated components.
If corrective maintenance is being done to one component, other components will be inspected
to see if maintenance is needed.
Maintenance Frequency
The maintenance indicators for selected BMPs are included in Attachment Al.
5
Debris and Sediment Disposal
Waste generated onsite is ultimately the responsibility of the Owner. Disposal of sediments, debris,
and trash will comply with applicable local, county, state, and federal waste control programs.
Hazardous Waste
Suspected hazardous wastes will be analyzed to determine disposal options. Hazardous wastes
generated onsite will be handled and disposed of according to applicable local, state, and federal
regulations. A solid or liquid waste is considered a hazardous waste if it exceeds the criteria listed in
the CCR, Title 22, Article ll.
C. Irrigation System
Inspection Frequency and Procedure
The Irrigation system shall be checked each week as a minimum. The following items shall be
checked to insure that they are functioning properly:
▪ Shut-off devices.
▪ All piping and sprinkler heads to insure there are no leaks and that proper water spread is
maintained.
▪ All flow reducers.
▪ Check for overspray/runoff
D. Trash Storage Areas
▪ All trash storage areas shall be inspected daily to insure that they are clean from trash. Also the
following shall be inspected annually 30 days prior to October lst of each year.
▪ Pavement is in good repair.
▪ Drainage will not run-off onto adjacent areas.
▪ That they remain screened or walled to prevent off-site transport of trash.
▪ That all lids are closed and/or awnings are in good repair to minimize direct
precipitation.
▪ Signs posted on or near dumpsters with the words “Do not dump hazardous
materials here” or similar.
E. Storm Water Conveyance System Stenciling and Signing
▪ Signage/stenciling are to be inspected for legibility and visual obstruction and shall be Repaired
and cleared of any obstruction within 5 working day of inspection.
6
▪ Inspection Frequency: Semi-annually, 30 days prior to October lst each year, and
monthly during rainy season.
F. Biofiltration
Operational and maintenance needs include:
▪ Vegetation management to maintain adequate hydraulic functioning and to limit habitat
for disease-carrying animals.
▪ Animal and vector control.
▪ Periodic sediment removal to optimize performance.
▪ Trash, debris, grass trimmings, tree pruning, dead vegetation collection and removal.
▪ Removal of standing water, which may contribute to the development of aquatic plant
communities or mosquito breeding areas.
▪ Erosion and structural maintenance to prevent the loss of soil and maintain the performance
of all landscaping.
▪ Outlet maintenance: maintain trash free; remove silt; clear clogged outlets and standing
Water after 96 hours.
▪ Signs Posted at each bmp that state the following words “ PERMANENT WATER
QUALITY TREATMENT FACILITY” “KEEPING OUR WATERWAYS CLEAN” “
MAINTAIN WITH CARE – NO MODIFICATIONS WITHOUT AGENCY APPROVAL”
G. Outlet Structures
All outlet structures shall be kept functional at all times. Routine inspection and corrective
maintenance shall include removal of trash sediment and debris and repair of any structural
damage or clogging of orifice outlets. The minimum maintenance frequency shall be 30 days
prior to October 1st each year, weekly during rainy season or within 24 hours prior to
forecasts.
To clean lower orifice in the event of clogging
▪ This activity will require workers to open catch basin grates to remove debris from the
lower orifice plate.
▪ Remove grate and visually inspect lower orifice plate and blockage
▪ Remove debris from inside of catch basin and around orifice plate
▪ Replace grate when orifice plate and inside of catch basin are free of debris
H. Vector Management Control Requirements
Due to Clean Water Act requirements and mandates imposed by the Water Quality Control Board,
large quantities of stormwater will be detained onsite in above ground and underground storage
facilities for treatment and storage. These storage facilities are required to dewater or discharge at a
very small flow rate in order to comply with these requirements. The outlet structure for the
underground storage and bioretention facility had to be sized to a variable size between 0.25” to 6” in
order to maintain the maximum allowed discharge flow. The facility was designed to dewater in less
than 96 hours. However, due to its small size and if not properly maintained regularly, it is anticipated
that the outlet might have a tendency to clog frequently. Consequently, the facility may not drain within
96 hours and possibly take substantially longer time. This creates an increased risk for onsite Vector
Issues and bringing their potential for severe harm to human health.
In order to implement vector controls including minimizing the risk for mosquito-borne disease
7
transmission, It is the responsibility of the Owner to regularly maintain the outlet structures
and monitor the site after every storm event to ensure that the system (comprising of above
ground storage facilities) is dewatered in less than 96 hours. Otherwise the owner will be required
to implement a vector control plan in accordance with California Department of Public Health.
General guidelines to help create a project specific vector control plan for your project:
ATTACHMENT “A1” INSPECTION & MAINTENANCE
SCHEDULE
PREVENTATIVE MAINTENANCE AND ROUTINE INSPECTION
TYPE BMP Routine Action Maintenance
Indicator
Maintenance
Frequency
MAINTENANCE
ACTIVITY
SITE-SPECIFIC REQUIREMENTS
Landscaping &
irrigation
Proper irrigation &
Fertilizer.
Less than 80%
coverage
30 days prior to
October 1st each year
and Monthly
Re-seed or Re- plant.
Repair Irrigation
system with-in 5-days.
All slopes and landscaped areas are to have a
minimum coverage of 80%
Trash storage
areas
Trash free and removal
of silt
Visual Inspection Daily inspection Remove trash and silt
Daily.
All trash storage areas to be free from trash
and silt at all times
Bioretention Trash free and removal of
silt. Clear Clogged outlets
and Standing Water.
Silt build up of more
than 2” no trash,
Exposed soils, dead
vegetation, ponded
water, and excessive
vegetation
(see TC-32)
30 days prior to
October 1st each
year, monthly during
rainy season, and
after Storm Event
Remove trash and silt –
repair and reseed
exposed areas, maintain
grass height so as not be
shorter than 2” or higher
than 5” remove all
ponded water weekly
inspections, (See TC-32)
All bio-filters to be free from trash and silt at all
times, grass area to be free from exposed soil
and maintained to proper height, ponding of
water for more than 72 hours maintenance will
be required
Storm Water
Conveyance
system
Stenciling &
Signing
Must be legible at all times
and have a clear view.
Fading of paint or
illegible letters or
Semi-annually, 30
days prior to October
1st each year &
monthly during rainy
season
Repaint stenciling and/or
replace signs 30 days
prior to October 1st.
Applicable to all stenciling and signs
Outlet
Structures
Must be kept functional at
all times. Clear Clogged
outlets and Standing
Water.
Silt, debris, trash
accumulation, Ponding
Water
30 days prior to
October 1st each
year and weekly
during rainy season
or within 24 hours
prior to rain forecasts.
Silt, debris, trash
accumulation and repair
any structural damage
to the outlet structures.
All outlet structures shall be kept functional at all
times.
9
ATTACMENT “B1”
Annual Estimate to Maintain all BMPs
Landscaping & Bioretention
Annual 10-Year
Maintenance of landscaping and bio-filters is already included in the
property management responsibilities. Additional cost:
$200
$2,000
Irrigation System:
Inspection and maintenance of the irrigation system is already included
in the property management responsibilities, Additional cost:
$100
$1,000
Training:
Once a year & training of new employees within their first
week of employment. $100 $1,000
Total Estimated Annual Cost to Maintain BMPs
ATTACHMENT "C1"
BMP TRAINING LOG
Date
Type of Training
Personnel
Trained
Trainer
Mo/Day/Yr
ATTACHMENT “D1”
INSPECTION AND MAINTENANCE LOG
BMP TYP &
LOCATION
DATE
M/D/Y
Name of
Person
Inspecting
Description of BMP
Condition/ Description repair
required if any
Date Repair made
and Description repair
made and by who
ATTACHMENT "D1"
INSPECTION AND MAINTENANCE LOG
BMP TYP &
LOCATION
DATE
M/D/Y
Name of
Person
Inspecting
Description of BMP
Condition/ Description repair
required if any
Date Repair made
and Description repair
made and by who
ATTACHMENT "D1"
INSPECTION AND MAINTENANCE LOG
BMP TYP &
LOCATION
DATE
M/D/Y
Name of
Person
Inspecting
Description of BMP
Condition/ Description repair
required if any
Date Repair made
and Description repair
made and by who
ATTACHMENT 3 STRUCTURAL BMP
MAINTENANCE INFORMATION
ATTACHMENT E1. MAINTENANCE INDICATORS
TABLE 7-2. Maintenance Indicators and Actions for Vegetated BMPs
Typical Maintenance Indicator(s)
for Vegetated BMPs Maintenance Actions
Accumulation of sediment, litter, or
debris
Remove and properly dispose of accumulated materials, without
damage to the vegetation.
Poor vegetation establishment Re-seed, re-plant, or re-establish vegetation per original plans.
Overgrown vegetation Mow or trim as appropriate, but not less than the design height of
the vegetation per original plans when applicable (e.g. a vegetated
swale may require a minimum vegetation height).
Erosion due to concentrated irrigation
flow
Repair/re-seed/re-plant eroded areas and adjust the irrigation
system.
Typical Maintenance
Indicator(s) for Vegetated BMPs Maintenance Actions
Erosion due to concentrated storm water
runoff flow
Repair/re-seed/re-plant eroded areas, and make appropriate
corrective measures such as adding erosion control blankets,
adding stone at flow entry points, or minor re-grading to restore
proper drainage according to the original plan. If the issue is not
corrected by restoring the BMP to the original plan and grade, the
[City Engineer] shall be contacted prior to any additional repairs or
reconstruction.
Standing water in vegetated swales Make appropriate corrective measures such as adjusting irrigation
system, removing obstructions of debris or invasive vegetation,
loosening or replacing top soil to allow for better infiltration, or
minor re-grading for proper drainage. If the issue is not corrected
by restoring the BMP to the original plan and grade, the [City
Engineer] shall be contacted prior to any additional repairs or
reconstruction.
Standing water in bioretention,
biofiltration with partial retention, or
biofiltration areas, or flow-through
planter boxes for longer than 96 hours
following a storm event*
Make appropriate corrective measures such as adjusting irrigation
system, removing obstructions of debris or invasive vegetation,
clearing underdrains (where applicable), or repairing/replacing
clogged or compacted soils.
Obstructed inlet or outlet structure Clear obstructions.
Damage to structural components such
as weirs, inlet or outlet structures
Repair or replace as applicable.
*These BMPs typically include a surface ponding layer as part of their function which may take 96 hours to
drain following a storm event.
TABLE 7-3. Maintenance Indicators and Actions for Non-Vegetated Infiltration BMPs
Typical Maintenance Indicator(s)
for Non-Vegetated Infiltration
BMPs Maintenance Actions
Accumulation of sediment, litter, or
debris in infiltration basin,
pretreatment device, or on permeable
pavement surface
Remove and properly dispose accumulated materials.
Standing water in infiltration basin
without subsurface infiltration gallery
for longer than 96 hours following a
storm event
Remove and replace clogged surface soils.
Standing water in subsurface
infiltration gallery for longer than 96
hours following a storm event
This condition requires investigation of why infiltration is not
occurring. If feasible, corrective action shall be taken to restore
infiltration (e.g. flush fine sediment or remove and replace clogged
soils). BMP may require retrofit if infiltration cannot be restored.
If retrofit is necessary, the [City Engineer] shall be contacted prior
to any repairs or reconstruction.
Standing water in permeable paving
area
Flush fine sediment from paving and subsurface gravel. Provide
routine vacuuming of permeable paving areas to prevent clogging.
Note: When inspection or maintenance indicates sediment is accumulating in an infiltration BMP,
the DMA draining to the infiltration BMP should be examined to determine the source of the
sediment, and corrective measures should be made as applicable to minimize the sediment supply.
TABLE 7-4. Maintenance Indicators and Actions for Filtration BMPs
Typical Maintenance Indicator(s) for
Filtration BMPs Maintenance Actions
Accumulation of sediment, litter, or debris Remove and properly dispose accumulated materials.
Obstructed inlet or outlet structure Clear obstructions.
Clogged filter media Remove and properly dispose filter media, and replace with fresh
media.
Damage to components of the filtration
system Repair or replace as applicable.
Note: For proprietary media filters, refer to the manufacturer's maintenance guide.
Appendix E: BMP Design Fact Sheets
E-4 February 26, 2016
If These Sources Will Be on the Project Site … … Then Your SWQMP Must Consider These Source Control BMPs
1 Potential Sources of Runoff Pollutants
2 Permanent Controls—Show on Drawings
3 Permanent Controls—List in Table and Narrative
4 Operational BMPs—Include in Table and Narrative
A. Onsite storm drain inlets
Not Applicable
Locations of inlets. Mark all inlets with the words “No Dumping! Flows to Bay” or similar. See stencil template provided in
Appendix I-4
Maintain and periodically repaint
or replace inlet markings.
Provide storm water pollution prevention information to new
site owners, lessees, or operators.
See applicable operational BMPs in Fact Sheet SC-44, “Drainage
System Maintenance,” in the CASQA Storm Water Quality
Handbooks at www.casqa.org/resources/bmp-
handbooks/municipal-bmp-handbook.
Include the following in lease
agreements: “Tenant shall not
allow anyone to discharge
anything to storm drains or to
store or deposit materials so as to
create a potential discharge to
storm drains.”
Appendix E: BMP Design Fact Sheets
E-5 February 26, 2016
If These Sources Will Be on the Project Site … … Then Your SWQMP must consider These Source Control BMPs
1 Potential Sources of Runoff Pollutants
2 Permanent Controls—Show on Drawings
3 Permanent Controls—List in Table and Narrative
4 Operational BMPs—Include in Table and Narrative
B. Interior floor
drains and elevator
shaft sump pumps
Not Applicable
State that interior floor drains and
elevator shaft sump pumps will be plumbed to sanitary sewer.
Inspect and maintain drains to
prevent blockages and overflow.
C. Interior parking
garages
Not Applicable
State that parking garage floor
drains will be plumbed to the sanitary sewer.
Inspect and maintain drains to
prevent blockages and overflow.
D1. Need for future indoor & structural
pest control
Not Applicable
Note building design features that
discourage entry of pests.
Provide Integrated Pest
Management information to owners, lessees, and operators.
Appendix E: BMP Design Fact Sheets
E-6 February 26, 2016
If These Sources Will Be on the Project Site … … Then Your SWQMP must consider These Source Control BMPs
1 Potential Sources of Runoff Pollutants
2 Permanent Controls—Show on Drawings
3 Permanent Controls—List in Table and Narrative
4 Operational BMPs—Include in Table and Narrative
D2. Landscape/ Outdoor Pesticide Use
Not Applicable
Show locations of existing
trees or areas of shrubs and ground cover to be
undisturbed and retained.
Show self-retaining landscape areas, if any.
Show storm water treatment facilities.
State that final landscape plans will
accomplish all of the following.
Preserve existing drought tolerant
trees, shrubs, and ground cover to the
maximum extent possible.
Design landscaping to minimize
irrigation and runoff, to promote surface infiltration where appropriate,
and to minimize the use of fertilizers and pesticides that can contribute to
storm water pollution.
Where landscaped areas are used to
retain or detain storm water, specify plants that are tolerant of periodic
saturated soil conditions.
Consider using pest-resistant plants, especially adjacent to hardscape.
To ensure successful establishment,
select plants appropriate to site soils, slopes, climate, sun, wind, rain, land
use, air movement, ecological consistency, and plant interactions.
Maintain landscaping using
minimum or no pesticides.
See applicable operational
BMPs in Fact Sheet SC-41,
“Building and Grounds Maintenance,” in the CASQA
Storm Water Quality Handbooks at
www.casqa.org/resources/bmp-handbooks/municipal-bmp-
handbook.
Provide IPM information to
new owners, lessees and
operators.
Appendix E: BMP Design Fact Sheets
E-7 February 26, 2016
If These Sources Will Be on the Project Site … … Then Your SWQMP must consider These Source Control BMPs
1 Potential Sources of Runoff Pollutants
2 Permanent Controls—Show on Drawings
3 Permanent Controls—List in Table and Narrative
4 Operational BMPs—Include in
Table and Narrative
E. Pools, spas,
ponds, decorative
fountains, and other
water features.
Not Applicable
Show location of water feature and a sanitary sewer cleanout in
an accessible area within 10 feet.
If the local municipality requires pools to be plumbed to the sanitary
sewer, place a note on the plans and state in the narrative that this
connection will be made according to local requirements.
See applicable operational BMPs in Fact Sheet SC-72,
“Fountain and Pool Maintenance,” in the CASQA
Storm Water Quality Handbooks at
www.casqa.org/resources/bmp-handbooks/municipal-
bmp-handbook.
F. Food service
Not Applicable
For restaurants, grocery stores, and other food service
operations, show location (indoors or in a covered area
outdoors) of a floor sink or other area for cleaning floor mats,
containers, and equipment.
On the drawing, show a note that
this drain will be connected to a
grease interceptor before
discharging to the sanitary sewer.
Describe the location and features of the designated cleaning area.
Describe the items to be cleaned in
this facility and how it has been sized to ensure that the largest items can be
accommodated.
Appendix E: BMP Design Fact Sheets
E-8 February 26, 2016
If These Sources Will Be on the Project Site
… … Then Your SWQMP must consider These Source Control BMPs
1 Potential Sources of
2 Permanent Controls—Show on Drawings
3 Permanent Controls—List in Table and Narrative
4 Operational BMPs—Include in Table and Narrative
G. Refuse areas
Not Applicable
Show where site refuse and
recycled materials will be handled and stored for
pickup. See local municipal requirements for sizes and
other details of refuse areas.
If dumpsters or other receptacles are outdoors,
show how the designated area will be covered, graded,
and paved to prevent run- on and show locations of
berms to prevent runoff from the area. Also show
how the designated area will be protected from wind
dispersal.
Any drains from dumpsters, compactors, and tallow bin
areas must be connected to a grease removal device
before discharge to sanitary sewer.
State how site refuse will
be handled and provide supporting detail to what
is shown on plans.
State that signs will be
posted on or near
dumpsters with the
words “Do not dump
hazardous materials
here” or similar.
State how the following will be implemented:
Provide adequate number of receptacles. Inspect receptacles regularly; repair or replace leaky
receptacles. Keep receptacles covered.
Prohibit/prevent dumping of liquid or hazardous
wastes. Post “no hazardous materials” signs. Inspect
and pick up litter daily and clean up spills
immediately. Keep spill control materials available
on- site. See Fact Sheet SC-34, “Waste Handling and
Disposal” in the CASQA Storm Water Quality
Handbooks at www.casqa.org/resources/bmp-
handbooks/municipal-bmp-handbook.
Appendix E: BMP Design Fact Sheets
E-9 February 26, 2016
If These Sources Will Be on the Project Site … … Then Your SWQMP must consider These Source Control BMPs
1 Potential Sources of Runoff Pollutants
2 Permanent Controls—Show on Drawings
3 Permanent Controls—List in Table and Narrative
4 Operational BMPs—Include in Table and Narrative
Table and Narrative
H. Industrial
processes.
Not Applicable
Show process area. If industrial processes are to be located onsite, state: “All process activities to be
performed indoors. No processes to drain to exterior or to storm drain
system.”
See Fact Sheet SC-10, “Non- Storm Water Discharges” in
the CASQA Storm Water Quality Handbooks at
https://www.casqa.org/resources/bmp-handbooks.
I. Outdoor storage
of equipment or
materials. (See rows J
and K for source
control measures for
vehicle cleaning,
repair, and
maintenance.)
Not Applicable
Show any outdoor storage
areas, including how materials will be covered. Show how
areas will be graded and bermed to prevent run-on or
runoff from area and protected from wind dispersal.
Storage of non-hazardous
liquids must be covered by a roof and/or drain to the
sanitary sewer system, and be contained by berms, dikes,
liners, or vaults.
Storage of hazardous materials and wastes must be in
compliance with the local hazardous materials ordinance
and a Hazardous Materials Management Plan for the site.
Include a detailed description of
materials to be stored, storage areas, and structural features to prevent pollutants
from entering storm drains.
Where appropriate, reference
documentation of compliance with the
requirements of local Hazardous
Materials Programs for:
Hazardous Waste Generation
Hazardous Materials Release
Response and Inventory
California Accidental Release
Prevention Program
Aboveground Storage Tank
Uniform Fire Code Article 80
Section 103(b) & (c) 1991
Underground Storage Tank
See the Fact Sheets SC-31,
“Outdoor Liquid Container Storage” and SC-33,
“Outdoor Storage of Raw Materials” in the CASQA
Storm Water Quality Handbooks at
www.casqa.org/resources/bmp-handbooks/municipal-bmp-
handbook.
Appendix E: BMP Design Fact Sheets
E-10 February 26, 2016
If These Sources Will Be on the Project Site … … Then Your SWQMP must consider These Source Control BMPs
1 Potential Sources of Runoff Pollutants
2 Permanent Controls—Show on Drawings
3 Permanent Controls—List in Table and Narrative
4 Operational BMPs—Include in Table and Narrative
J. Vehicle and
Equipment Cleaning
Not Applicable
Show on drawings as appropriate:
(1) Commercial/industrial facilities having
vehicle /equipment cleaning needs must
either provide a covered, bermed area for
washing activities or discourage
vehicle/equipment washing by removing
hose bibs and installing signs prohibiting such
uses.
(2) Multi-dwelling complexes must have a
paved, bermed, and covered car wash area
(unless car washing is prohibited onsite and
hoses are provided with an automatic shut-
off to discourage such use).
(3) Washing areas for cars, vehicles, and equipment must be paved, designed to
prevent run-on to or runoff from the area, and plumbed to drain to the sanitary sewer.
(4) Commercial car wash facilities must be designed such that no runoff from the facility
is discharged to the storm drain system. Wastewater from the facility must discharge
to the sanitary sewer, or a wastewater reclamation system must be installed.
If a car wash area is not
provided, describe measures
taken to discourage onsite
car washing and explain how
these will be enforced.
Describe operational measures to
implement the following (if
applicable):
Washwater from vehicle and equipment washing operations
must not be discharged to the storm drain system.
Car dealerships and similar may rinse cars with water only.
See Fact Sheet SC-21,
“Vehicle and Equipment Cleaning,” in the CASQA
Storm Water Quality Handbooks at
www.casqa.org/resources/bmp-handbooks/municipal-bmp-
handbook.
Appendix E: BMP Design Fact Sheets
E-11 February 26, 2016
If These Sources Will Be on the Project Site … … Then Your SWQMP must consider These Source Control BMPs
1 Potential Sources of Runoff Pollutants
2 Permanent Controls—Show on Drawings
3 Permanent Controls—List in Table and Narrative
4 Operational BMPs—Include in Table and Narrative
K.
Vehicle/Equipment
Repair and Maintenance
Not Applicable
Accommodate all vehicle
equipment repair and
maintenance indoors. Or
designate an outdoor work area
and design the area to protect
from rainfall, run-on runoff, and
wind dispersal.
Show secondary containment for
exterior work areas where motor
oil, brake fluid, gasoline, diesel fuel, radiator fluid, acid-
containing batteries or other hazardous materials or hazardous wastes are used or stored. Drains
must not be installed within the secondary containment areas.
Add a note on the plans that
states either (1) there are no floor
drains, or (2) floor drains are
connected to wastewater
pretreatment systems prior to discharge to the sanitary sewer
and an industrial waste discharge permit will be obtained.
State that no vehicle repair or
maintenance will be done
outdoors, or else describe the
required features of the
outdoor work area.
State that there are no floor
drains or if there are floor
drains, note the agency from which an industrial waste
discharge permit will be obtained and that the design
meets that agency’s requirements.
State that there are no tanks,
containers or sinks to be used for parts cleaning or rinsing
or, if there are, note the agency from which an
industrial waste discharge permit will be obtained and
that the design meets that agency’s requirements.
In the report, note that all of the following
restrictions apply to use the site:
No person must dispose of, nor permit the disposal, directly or indirectly of
vehicle fluids, hazardous materials, or rinsewater from parts cleaning into
storm drains.
No vehicle fluid removal must be performed outside a building, nor on
asphalt or ground surfaces, whether inside or outside a building, except in
such a manner as to ensure that any spilled fluid will be in an area of
secondary containment. Leaking
vehicle fluids must be contained or
drained from the vehicle immediately.
No person must leave unattended drip
parts or other open containers
containing vehicle fluid, unless such
containers are in use or in an area of secondary containment.
Appendix E: BMP Design Fact Sheets
E-12 February 26, 2016
If These Sources Will Be on the Project Site … … Then Your SWQMP must consider These Source Control BMPs
1 Potential Sources of Runoff Pollutants
2 Permanent Controls—Show on Drawings
3 Permanent Controls—List in Table and Narrative
4 Operational BMPs—Include in Table and Narrative
L. Fuel Dispensing
Areas
Not Applicable
Fueling areas16 must have
impermeable floors (i.e., portland
cement concrete or equivalent smooth
impervious surface) that are (1) graded
at the minimum slope necessary to
prevent ponding; and (2) separated
from the rest of the site by a grade
break that prevents run-on of storm
water to the MEP.
Fueling areas must be covered by a
canopy that extends a minimum of ten feet in each direction from each
pump. [Alternative: The fueling area must be covered and the cover’s
minimum dimensions must be equal to or greater than the area within the
grade break or fuel dispensing area1.] The canopy [or cover] must not drain
onto the fueling area.
The property owner must dry sweep
the fueling area routinely.
See the Business Guide Sheet,
“Automotive Service—Service Stations” in the CASQA Storm
Water Quality Handbooks at https://www.casqa.org/resources/b
mp-handbooks.
16 The fueling area must be defined as the area extending a minimum of 6.5 feet from the corner of each fuel dispenser or the length at which the hose and nozzle assembly may be
operated plus a minimum of one foot, whichever is greater.
Appendix E: BMP Design Fact Sheets
E-13 February 26, 2016
If These Sources Will Be on the Project Site … … Then Your SWQMP must consider These Source Control BMPs
1 Potential Sources of Runoff Pollutants
2 Permanent Controls—Show on Drawings
3 Permanent Controls—List in
4 Operational BMPs—Include in Table and Narrative
M. Loading Docks
Not Applicable
Show a preliminary design for the
loading dock area, including
roofing and drainage. Loading
docks must be covered and/or
graded to minimize run-on to and
runoff from the loading area. Roof
downspouts must be positioned to
direct storm water away from the
loading area. Water from loading
dock areas should be drained to
the sanitary sewer where feasible.
Direct connections to storm
drains from depressed loading
docks are prohibited.
Loading dock areas draining
directly to the sanitary sewer must
be equipped with a spill control
valve or equivalent device, which
must be kept closed during
periods of operation.
Provide a roof overhang over the
loading area or install door skirts
(cowling) at each bay that enclose
the end of the trailer.
Move loaded and unloaded items indoors as
soon as possible.
See Fact Sheet SC-30, “Outdoor Loading and
Unloading,” in the CASQA Storm Water Quality Handbooks at
www.casqa.org/resources/bmp-handbooks/municipal-bmp-handbook.
Appendix E: BMP Design Fact Sheets
E-14 February 26, 2016
If These Sources Will Be on the Project Site … … Then Your SWQMP must consider These Source Control BMPs
1 Potential Sources of Runoff Pollutants
2 Permanent Controls—Show on Drawings
3 Permanent Controls—List in Table and Narrative
4 Operational BMPs—Include in Table and Narrative
N. Fire Sprinkler
Test Water
Not Applicable
Provide a means to drain fire sprinkler test water
to the sanitary sewer.
See the note in Fact Sheet SC-
41, “Building and Grounds
Maintenance,” in the CASQA
Storm Water Quality
Handbooks at
www.casqa.org/resources/bm
p-handbooks/municipal-bmp-
handbook
O. Miscellaneous Drain or Wash Water
Boiler drain lines
Condensate drain lines
Rooftop
equipment
Drainage sumps
Roofing, gutters,
and trim
Not Applicable
Boiler drain lines must be directly or indirectly connected to the sanitary sewer system and may
not discharge to the storm drain system.
Condensate drain lines may discharge to landscaped areas if the flow is small enough that
runoff will not occur. Condensate drain lines may not discharge to the storm drain system.
Rooftop mounted equipment with potential to
produce pollutants must be roofed and/or have secondary containment.
Any drainage sumps onsite must feature a
sediment sump to reduce the quantity of
sediment in pumped water.
Avoid roofing, gutters, and trim made of copper or other unprotected metals that may leach into
runoff.
Appendix E: BMP Design Fact Sheets
E-15 February 26, 2016
If These Sources Will Be
on the Project Site … … Then Your SWQMP must consider These Source Control BMPs
1 Potential Sources of
Runoff Pollutants
2 Permanent Controls—Show on
Drawings
3 Permanent Controls—List in
Table and Narrative
4 Operational BMPs—Include in
Table and Narrative
P. Plazas, sidewalks, and
parking lots.
Not Applicable
Plazas, sidewalks, and parking lots must
be swept regularly to prevent the
accumulation of litter and debris.
Debris from pressure washing must be
collected to prevent entry into the
storm drain system. Washwater
containing any cleaning agent or
degreaser must be collected and
discharged to the sanitary sewer and
not discharged to a storm drain.
OPERATION & MAINTENANCE
Bio Clean Environmental Services, Inc.
398 Via El Centro
Oceanside, CA 92058
www.BioCleanEnvironmental.com
p: 760.433.7640
f: 760.433.3176
Grate Inlet Filter
Bio~Clean
A Forterra Company
1 | Page
OPERATION & MAINTENANCE
The Bio Clean Grate Inlet Filter is a stormwater device designed to remove high levels of trash,
debris, sediments and hydrocarbons. The filter is available in several configurations including trash
full capture, multi‐level screening, Kraken membrane filter and media filter variations. This manual
covers maintenance procedures of the trash full capture and multi‐level screening configurations. A
supplemental manual is available for the Kraken and media filter variations. This filter is made of
100% stainless steel and is available and various sizes and depths allowing it to fit in any grated
catch basin inlet. The filters heavy duty construction allows for cleaning with any vacuum truck. The
filet can also easily be cleaned by hand.
As with all stormwater BMPs, inspection and maintenance on the Grate Inlet Filter is necessary.
Stormwater regulations require BMPs be inspected and maintained to ensure they are operating as
designed to allow for effective pollutant removal and provide protection to receiving water bodies.
It is recommended that inspections be performed multiple times during the first year to assess site‐
specific loading conditions. This is recommended because pollutant loading can vary greatly from
site to site. Variables such as nearby soil erosion or construction sites, winter sanding of roads,
amount of daily traffic and land use can increase pollutant loading on the system. The first year of
inspections can be used to set inspection and maintenance intervals for subsequent years. Without
appropriate maintenance a BMP can exceed its storage capacity which can negatively affect its
continued performance in removing and retaining captured pollutants.
System Diagram:
H!ghi Flow
Bypass
Outlet Pipe
Bio ~Clean
A Forterra Company
l=fydroceubon
Boom
~---Mountllng1
Flange
2 | Page
Inspection Equipment
Following is a list of equipment to allow for simple and effective inspection of the Grate Inlet Filter:
Bio Clean Environmental Inspection Form (contained within this manual).
Manhole hook or appropriate tools to remove access hatches and covers.
Appropriate traffic control signage and procedures.
Protective clothing and eye protection.
Note: entering a confined space requires appropriate safety and certification. It is generally
not required for routine inspections or maintenance of the system.
Inspection Steps
The core to any successful stormwater BMP maintenance program is routine inspections. The
inspection steps required on the Grate Inlet Filter are quick and easy. As mentioned above the first
year should be seen as the maintenance interval establishment phase. During the first year more
frequent inspections should occur in order to gather loading data and maintenance requirements
for that specific site. This information can be used to establish a base for long‐term inspection and
maintenance interval requirements.
The Grate Inlet Filter can be inspected though visual observation. All necessary pre‐inspection steps
must be carried out before inspection occurs, such as safety measures to protect the inspector and
nearby pedestrians from any dangers associated with an open grated inlet. Once the grate has been
safely removed the inspection process can proceed:
Prepare the inspection form by writing in the necessary information including project name,
location, date & time, unit number and other info (see inspection form).
Observe the filter with the grate removed.
Look for any out of the ordinary obstructions on the grate or in the filter and its bypass.
Write down any observations on the inspection form.
Through observation and/or digital photographs estimate the amount of trash, foliage and
sediment accumulated inside the filter basket. Record this information on the inspection
form.
Observe the condition and color of the hydrocarbon boom. Record this information on the
inspection form.
Finalize inspection report for analysis by the maintenance manager to determine if
maintenance is required.
Bio ~Clean
A Forterra Company
3 | Page
Maintenance Indicators
Based upon observations made during inspection, maintenance of the system may be required
based on the following indicators:
Missing or damaged internal components.
Obstructions in the filter basket and its bypass.
Excessive accumulation of trash, foliage and sediment in the filter basket. Maintenance is
required when the basket is greater than half‐full.
The following chart shows the 50% and 100% storage capacity of each filter height:
Model Filter Basket
Diameter (in)
Filter Basket
Height (in)
50% Storage
Capacity (cu ft)
100% Storage
Capacity (cu ft)
BC‐GRATE‐12‐12‐12 10.00 12.00 0.27 0.55
BC‐GRATE‐18‐18‐18 16.00 18.00 1.05 2.09
BC‐GRATE‐24‐24‐24 21.00 24.00 2.41 4.81
BC‐GRATE‐30‐30‐24 27.00 24.00 3.98 7.95
BC‐GRATE‐36‐36‐24 33.00 24.00 5.94 11.88
BC‐GRATE‐48‐48‐18 44.00 18.00 7.92 15.84
Maintenance Equipment
It is recommended that a vacuum truck be utilized to minimize the time required to maintain the
Curb Inlet Filter, though it can easily cleaned by hand:
Bio Clean Environmental Maintenance Form (contained in O&M Manual).
Manhole hook or appropriate tools to remove the grate.
Appropriate safety signage and procedures.
Protective clothing and eye protection.
Note: entering a confined space requires appropriate safety and certification. It is generally
not required for routine maintenance of the system. Small or large vacuum truck (with
pressure washer attachment preferred).
Maintenance Procedures
It is recommended that maintenance occurs at least two days after the most recent rain event to
allow debris and sediments to dry out. Maintaining the system while flows are still entering it will
increase the time and complexity required for maintenance. Cleaning of the Grate Inlet Filter can be
performed utilizing a vacuum truck. Once all safety measures have been set up cleaning of the
Grate Inlet Filter can proceed as followed:
Bio ~Clean
A Forterra Company
4 | Page
Remove grate (traffic control and safety measures to be completed prior).
Using an extension on a vacuum truck position the hose over the opened catch basin. Insert
the vacuum hose down into the filter basket and suck out trash, foliage and sediment. A
pressure wash is recommended and will assist in spraying of any debris stuck on the side or
bottom of the filter basket. Power wash off the filter basket sides and bottom.
Next remove the hydrocarbon boom that is attached to the inside of the filter basket. The
hydrocarbon boom is fastened to rails on two opposite sides of the basket (vertical rails).
Assess the color and condition of the boom using the following information in the next
bullet point. If replacement is required install and fasten on a new hydrocarbon boom.
Booms can be ordered directly from the manufacturer.
Follow is a replacement indication color chart for the hydrocarbon booms:
The last step is to replace the grate and remove all traffic control.
All removed debris and pollutants shall be disposed of following local and state
requirements.
Disposal requirements for recovered pollutants may vary depending on local guidelines. In
most areas the sediment, once dewatered, can be disposed of in a sanitary landfill. It is not
anticipated that the sediment would be classified as hazardous waste.
In the case of damaged components, replacement parts can be ordered from the
manufacturer. Hydrocarbon booms can also be ordered directly from the manufacturer as
previously noted.
Excellent
Condition
Good Condition
Minimal Capacity
Replacement Required
Bio ~Clean
A Forterra Company
5 | Page
Maintenance Sequence
Insert the vacuum hose down into the filter basket and suck out debris. Use a pressure washer to assist in vacuum removal.
Pressure wash off screens.
Remove grate and set up vacuum truck to clean the filter basket.
Bio ~Clean
A Forterra Company
6 | Page
For Maintenance Services or
Information Please Contact Us At:
760‐433‐7640
Or Email:
info@biocleanenvironmental.com
Remove the hydrocarbon boom
that is attached to the inside of the
filter basket. The hydrocarbon
boom is fastened to rails on two
opposite sides of the basket
(vertical rails). Assess the color and
condition of the boom using the
following information in the next
bullet point. If replacement is
required install and fasten on a
new hydrocarbon boom.
Close up and replace the
grate and remove all traffic
control. All removed debris
and pollutants shall be
disposed of following local
and state requirements.
Bio ~Clean
A Forterra Company
For Office Use Only
(city) (Zip Code)(Reviewed By)
Owner / Management Company
(Date)
Contact Phone ( )_
Inspector Name Date / / Time AM / PM
Weather Condition Additional Notes
Site
Map #
Long:
Storm Event in Last 72-hours? No Yes
GPS Coordinates of
Insert Catch Basin Size
Evidence of
Illicit
Discharge?
Trash
Accumulation
Type of Inspection Routine Follow Up Complaint Storm
Lat:
Long:
Lat:
Long:
Sediment
Accumulation
Office personnel to complete section to the
left.
Functioning Properly or
Maintenance Needed?
398 Via El Centro, Oceanside, CA 92058 P. 760.433.7640 F. 760.433.3176
Comments:
Foliage
Accumulation
Long:
Lat:
Long:
Lat:
3 Lat:
2
1
Long:
Inspection and Maintenance Report
Catch Basin Only
Signs of Structural
Damage?
5
4
6 Lat:
Lat:
Lat:
Long:
7
Lat:
Long:
10
8
Long:
Project Name
Project Address
12 Lat:
11 Lat:
Long:
Long:
Bio ~Clean
A Forterra Company
-----
□ □ □ □ □
ATTACHMENT 3A - OCTOBER 2022 1
ATTACHMENT 3a
STRUCTURAL MAINTENANCE PLAN
ATTACHMENT 3A - OCTOBER 2022 2
MAINTENACE INDICATORS
Typical Maintenance Indicator(s)
for Vegetated BMPs Maintenance Actions
Accumulation of sediment, litter, or
debris
Remove and properly dispose of accumulated materials, without
damage to the vegetation.
Poor vegetation establishment Re-seed, re-plant, or re-establish vegetation per original plans.
Overgrown vegetation
Mow or trim as appropriate, but not less than the design height of
the vegetation per original plans when applicable (e.g. a vegetated
swale may require a minimum vegetation height).
Erosion due to concentrated irrigation
flow
Repair/re-seed/re-plant eroded areas and adjust the irrigation
system.
Erosion due to concentrated storm water
runoff flow
Repair/re-seed/re-plant eroded areas, and make appropriate
corrective measures such as adding erosion control blankets,
adding stone at flow entry points, or minor re-grading to restore
proper drainage according to the original plan. If the issue is not
corrected by restoring the BMP to the original plan and grade,
The County must be contacted prior to any additional repairs or
reconstruction.
Standing water in vegetated swales
Make appropriate corrective measures such as adjusting irrigation
system, removing obstructions of debris or invasive vegetation,
loosening or replacing top soil to allow for better infiltration, or
minor re-grading for proper drainage. If the issue is not corrected
by restoring the BMP to the original plan and grade, County staff
in the Watershed Protection Program must be contacted prior to
any additional repairs or reconstruction.
Standing water in bioretention,
biofiltration with partial retention, or
biofiltration areas, or flow-through
planter boxes for longer than 96 hours
following a storm event*
Make appropriate corrective measures such as adjusting irrigation
system, removing obstructions of debris or invasive vegetation,
clearing underdrains (where applicable), or repairing/replacing
clogged or compacted soils.
Obstructed inlet or outlet structure Clear obstructions.
Damage to structural components such as
weirs, inlet or outlet structures Repair or replace as applicable.
*These BMPs typically include a surface ponding layer as part of their function which may take 96 hours to
drain following a storm event.
ATTACHMENT 3A - OCTOBER 2022 3
ACCESS AND MAINTENANCE
Structural BMP-A
Structural BMP-A is constructed in the northeast corner of the proposed medical office building.
Please see Figure I.11-2 of Attachment 3b for site overview and BMP location. Access for
inspection and maintenance is provided through the parking lot west of the structural BMP.
BMP-A is designed as a bioretention basin with a 36”x36” catch basin to attenuate a 100-year storm
event. The basin design consist of layered sand and gravel aggregate with 9” surface ponding.
Inspection of the outlet pipe will be performed through the grated lid of the catch basin. No
proprietary parts have been used in the construction of this bioretention basin.
Maintenance of BMP-A will be performed, at minimum, when these thresholds are exceeded:
• Grass higher than 4”
• Wilting and/or dying trees, shrubs or grass
• Erosive conditions cause ponding area side slopes to exceed 3:1
• Silt buildup of more than 2”
• Ponding surface drawdown time exceeds 24 hours
• Ponding elevation exceeds top of pond elevation
In order to perform maintenance on the structural BMP, it is recommended that lawn and shrub
care equipment be used. Compaction of BMP soils shall be avoided and it is recommended that
heavy equipment not be used.
No special training or certification is needed in inspecting or maintaining this BMP.
Structural BMP-B
Structural BMP-B is constructed on the northwest side the proposed medical office building. Please
see Figure I.11-2 of Attachment 3b for site overview and BMP location. Access for inspection and
maintenance is provided through the parking lot west of the structural BMP.
BMP-B is designed as a bioretention basin with a 24”x24” catch basin to attenuate a 100-year storm
event. The basin design consist of layered sand and gravel aggregate with 9” surface ponding.
Inspection of the outlet pipe will be performed through the grated lid of the catch basin. No
proprietary parts have been used in the construction of this bioretention basin.
Maintenance of BMP-B will be performed, at minimum, when these thresholds are exceeded:
• Grass higher than 4”
• Wilting and/or dying trees, shrubs or grass
• Erosive conditions cause ponding area side slopes to exceed 3:1
• Silt buildup of more than 2”
• Ponding surface drawdown time exceeds 24 hours
• Ponding elevation exceeds top of pond elevation
ATTACHMENT 3A - OCTOBER 2022 4
In order to perform maintenance on the structural BMP, it is recommended that lawn and shrub
care equipment be used. Compaction of BMP soils shall be avoided and it is recommended that
heavy equipment not be used.
No special training or certification is needed in inspecting or maintaining this BMP.
Structural BMP-C
Structural BMP-C is constructed in the northeast side of the proposed medical office building.
Please see Figure I.11-2 of Attachment 3b for site overview and BMP location. Access for
inspection and maintenance is provided through the parking lot west of the structural BMP.
BMP-C is designed as a bioretention basin with a 24”x24” catch basin to attenuate a 100-year storm
event. The basin design consist of layered sand and gravel aggregate with 9” surface ponding.
Inspection of the outlet pipe will be performed through the grated lid of the catch basin. No
proprietary parts have been used in the construction of this bioretention basin.
Maintenance of BMP-C will be performed, at minimum, when these thresholds are exceeded:
• Grass higher than 4”
• Wilting and/or dying trees, shrubs or grass
• Erosive conditions cause ponding area side slopes to exceed 3:1
• Silt buildup of more than 2”
• Ponding surface drawdown time exceeds 24 hours
• Ponding elevation exceeds top of pond elevation
In order to perform maintenance on the structural BMP, it is recommended that lawn and shrub
care equipment be used. Compaction of BMP soils shall be avoided and it is recommended that
heavy equipment not be used.
No special training or certification is needed in inspecting or maintaining this BMP.
Structural BMP-D
Structural BMP-D is constructed in the southeast side of the proposed medical office building.
Please see Figure I.11-2 of Attachment 3b for site overview and BMP location. Access for
inspection and maintenance is provided through the parking lot west of the structural BMP.
BMP-D is designed as a bioretention basin with a 24”x36” catch basin to attenuate a 100-year storm
event. The basin design consist of layered sand and gravel aggregate with 9” surface ponding.
Inspection of the outlet pipe will be performed through the grated lid of the catch basin. No
proprietary parts have been used in the construction of this bioretention basin.
Maintenance of BMP-D will be performed, at minimum, when these thresholds are exceeded:
• Grass higher than 4”
• Wilting and/or dying trees, shrubs or grass
• Erosive conditions cause ponding area side slopes to exceed 3:1
• Silt buildup of more than 2”
ATTACHMENT 3A - OCTOBER 2022 5
• Ponding surface drawdown time exceeds 24 hours
• Ponding elevation exceeds top of pond elevation
In order to perform maintenance on the structural BMP, it is recommended that lawn and shrub
care equipment be used. Compaction of BMP soils shall be avoided and it is recommended that
heavy equipment not be used.
No special training or certification is needed in inspecting or maintaining this BMP.
Structural BMP-E
Structural BMP-E is constructed in the southwest side of the proposed medical office building.
Please see Figure I.11-2 of Attachment 3b for site overview and BMP location. Access for
inspection and maintenance is provided through the parking lot west of the structural BMP.
BMP-E is designed as a bioretention basin with a 24”x24” catch basin to attenuate a 100-year storm
event. The basin design consist of layered sand and gravel aggregate with 9” surface ponding.
Inspection of the outlet pipe will be performed through the grated lid of the catch basin. No
proprietary parts have been used in the construction of this bioretention basin.
Maintenance of BMP-E will be performed, at minimum, when these thresholds are exceeded:
• Grass higher than 4”
• Wilting and/or dying trees, shrubs or grass
• Erosive conditions cause ponding area side slopes to exceed 3:1
• Silt buildup of more than 2”
• Ponding surface drawdown time exceeds 24 hours
• Ponding elevation exceeds top of pond elevation
In order to perform maintenance on the structural BMP, it is recommended that lawn and shrub
care equipment be used. Compaction of BMP soils shall be avoided and it is recommended that
heavy equipment not be used.
No special training or certification is needed in inspecting or maintaining this BMP.
Structural BMP-F
Structural BMP-F is constructed in the southwest side of the parcel near the driveway entrance off
Hidden Valley Road. Please see Figure I.11-2 of Attachment 3b for site overview and BMP location.
Access for inspection and maintenance is provided through the parking lot west of the structural
BMP.
BMP-F is designed as a bioretention basin with a 24”x24” catch basin to attenuate a 100-year storm
event. The basin design consist of layered sand and gravel aggregate with 9” surface ponding.
Inspection of the outlet pipe will be performed through the grated lid of the catch basin. No
proprietary parts have been used in the construction of this bioretention basin.
Maintenance of BMP-F will be performed, at minimum, when these thresholds are exceeded:
• Grass higher than 4”
ATTACHMENT 3A - OCTOBER 2022 6
• Wilting and/or dying trees, shrubs or grass
• Erosive conditions cause ponding area side slopes to exceed 3:1
• Silt buildup of more than 2”
• Ponding surface drawdown time exceeds 24 hours
• Ponding elevation exceeds top of pond elevation
In order to perform maintenance on the structural BMP, it is recommended that lawn and shrub
care equipment be used. Compaction of BMP soils shall be avoided and it is recommended that
heavy equipment not be used.
No special training or certification is needed in inspecting or maintaining this BMP.
ATTACHMENT 3B - OCTOBER 2022 1
ATTACHMENT 3b
DRAFT MAINTENANCE AGREEMENT
ATTACHMENT 3B - OCTOBER 2022 2
RECORDING REQUESTD BY:
WHEN RECORDED MAIL TO:
(property owner)
SPACE ABOVE THIS LINE FOR RECORDER’S USE
MAINTENANCE NOTIFICATION AGREEMENT FOR CATEGORY 1
STORMWATER STRUCTURAL BMP’s
THIS AGREEMENT is made on the day of , 20 .
, the Owner(s) of the hereinafter described real property:
Address , Post Office Zip Code
Assessor Parcel No.(s)
List, identify, locate (plan/drawing number) and describe the Structural
Owner(s) of the above property acknowledge the existence of the storm water Structural Best Management Practice on the said
property. Perpetual maintenance of the Structural BMP(s) is the requirement of the State NPDES Permit, Order No. R9-2015-0001,
Section E.3.e.(1)( c) and the County of San Diego Watershed Protection Ordinance (WPO) Ordinance No. 10385 Section 67.812
through Section 67.814, and County BMP Design Manual (BMP DM) Chapters 7 & 8. In consideration of the requirement to
construct and maintain Structural BMP(s), as conditioned by Discretionary Permit, Grading Permit, and/or Building Permit (as may be applicable), I/we hereby covenant and agree that:
1. I/We are the owner(s) of the existing (or to be constructed concurrently) premises located on the above described property.
2. I/We shall take the responsibility for the perpetual maintenance of the Structural BMP(s) as listed above in accordance with the maintenance plan and in compliance with County’s self-inspection reporting and verification for as long as I/we have ownership of said property(ies).
3. I/We shall cooperate with and allow the County staff to come onto said property(ies) and perform inspection duties as
prescribed by local and state regulators.
4. I/We shall inform future buyer(s) or successors of said property(ies) of the existence and perpetual maintenance requirement
responsibilities for Structural BMP(s) as listed above and to ensure that such responsibility shall transfer to the future owner(s). 5. I/We will abide by all of the requirements and standards of Section 67.812 through Section 67.814 of the WPO (or renumbering
thereof) as it exists on the date of this Agreement, and which hereby is incorporated herein by reference.
This Agreement shall run with the land. If the subject property is conveyed to any other person, firm, or corporation, the instrument
that conveys title or any interest in or to said property, or any portion thereof, shall contain a provision transferring maintenance responsibility for Structural BMP(s) to the successive owner according to the terms of this Agreement. Any violation of this
Agreement is grounds for the County to impose penalties upon the property owner as prescribed in County Code of Regulatory
Ordinances, Title 1, Division 8, Chapter 1 Administrative Citations §§18.101-18.116.
Owner(s) Signature(s)
Print Owner(s) Name(s) and Title
STATE OF CALIFORNIA ) COUNTY OF )
On before me, Notary Public,
personally appeared who proved to me on the basis of satisfactory evidence to be
the person(s) whose name(s) is/are subscribed to the within instrument and acknowledged to me that he/she/they executed the same in his/her/their authorized capacity(ies), and that by his/her/their signature(s) on the instrument the person(s) or the entity
upon behalf of which the person(s) acted, executed the instrument.
I certify under PENALTY OF PERJURY under the laws of the State of California that the foregoing paragraph is true and correct.
WITNESS my hand and official seal.
ATTACHMENT 4
City standard Single Sheet BMP (SSBMP) Exhibit
◊
◊
◊
◊
SINGLE SHEET BMP PLAN
NORTH COAST MEDICAL PLAZA PHASE I AND II
I I
'i
~tv )
\
\ !i 18 \ _ __,
\s,--...,,--..,
2J
.... ;.:.):•·: .---
L.
B#PNO!ES: BMPTABLE
BIIIP# BMPTYPE SYIIIBOL CASQA# QUANTITY DRAWING#
HYDROMODIFICATION & TREATMENT CONTROL
0-0 8/0RL TRA 110N 11111 11:-.J2 4589 SF 496-18
0 ROOF DRAIN trJ
LANOSCAPINC 0 SO-ff 4EA 496-18
SOURCE CONTROL
0-@ INLET
S!ENC/LINC N/,4 SD-1.J 6 EA. 496-18
® ll'A!ER _Q_ --496-18 (J(JALITY SICN l2EA.
@) LANDSCAPE SIJ-10 O/J11JOOR I· -:-:-·-:-: • -:-.I 496-18
P£S11C/lJ£ /IS£ SIJ-12
@ EFRC/ENT SIJ-.Jl I:::•:":::·": I 496-18 /RR/CA lltJN SIJ-J4
® TRASH COLLEClltJN 00 SIJ-J2 l £A 496-18 AREA
LOW IMPACT DESIGN (L.1.0.}
@ 1:·::::=:::::: :.1 SIJ 10 496 18 LANOSCAPING SIJ-12
TRASH CAPTURE BMPS
@-® /NI.ET flL 1ER l!!I TC-50 6EA. 496-18
MAINTENANCE AGREEMENT DOCUMENT.-~s ....J'.... NO __
RECOROAllON NO. ______ _
PARTY RESPONSIBLE FOR MAINTENANCE·
NAIi£· SSG 1H, LLC CONTAC!: 1111 HOAG
AOORESS 4365 EXECVllVE OR/VE; StJ/lE 1600
SAN 0/EGO, CA 92121
/ PLAN PREPARED BY.· I NAIi£· ROBERT 0. OENllNO
{ COIIPANY: EXCEL ENGINEERING
I AOORESS: 440 STAlE PLACE
ESCONOIOO, CA 92029
\ PHONE NO: (760)745-8118 CER11RCA110N: RCE 4.5629
PERMANENT WATER {)UAL/TY
TREATMENT FACILITY
i(ffP/,1/( ()f/F !i,11 T£f W;! !'S CL[l,ii
UA,WrAiN !:f,7-1 /;/,FF ,W) .ifrJ,•Jir~•(A.77,-/!vS i!,17/-1,)1/l .4,Y-N('i' .4."'Pf'/JVAi
OETAIL
BIO CLEAN FULL CAPTURE FILTER
FOR USE INGRA TE INLETS
PLAN VIEW
(GRATE NOT SHOWN)
HIGH FLOW
BYPASS
///LL!/ L/J //
,~_vvvvvvvvvv v
V V V V V V V V V V V VV V V
YVVYVVVYVVVVYV'
/ ··::::::~:::::::;:~::::::?· \
0""'"'""'"'"'""'" VVvVVVVVYV
TOP MOUNT
PINE
MOUNT
ANGLE
2• RANGE
4" BYPASS
COi/CRETE
GRATE
INLET
SHEET#{S} INSPECTION IIIAINTENANCE
FREQUENCY FREQUENCY
4, 7, 8 l){IAR!FRLY SEAII-ANNUALL Y
AS NEEJEIJ II/ 4, 7, 8 5££ NO!E !i EACH INSPECl
~ 7, 8 WAR !ERL Y ~ARLY
~ 7, 8 N/,4 N/,4
AS NEEJElJ II/ 4, 7, 8 S££ NO!E !i EACH INSPECl
AS NEEJElJ II/ 4, 7, 8 S££ NO!E !i EACH INSPECl
4, 7, 8 S££ NO!E !i AS NEEJEIJ II/
EACH INSPECl
4, 7, 8 S££ NO!E !i AS NEEJEIJ II/
EACH INSPECl
~ 7, 8 l){IAR!FRLY l){IAR!FRLY
L
ELEVATION VIEW
1111 I
WATER (){JAL/TY S/6N-PLACEO AT
EACII B/ORL lli'A llON BASIN
/ ·:::::::::::::::f \
oumow
FLOW DIAGRAM
I/ON-CLOGGING SCREEN
MEETS FULL CAPTURE
REQUIREMENTS
BOTTOM SCREE/I
MEETS FULL CAPTURE
REQUIREMENTS
MODEL j
TREATMENT
FLOW
RATE
(CFS)
BYPASS
FLOW
(CFS)
SOLIDS
STORAGE
CAPACITY
5• fli'EEBOARO OEPlH 01,£1i'
CATCH BASIN GRAlE
ELEVAllON
II/PER/I/OLIS LINER-'--"=""'
TORAGE OEPlH PER BIO
RL1RA110N St/Ill/ARY
TABLE Al PLANllNG PER
LANDSCAPE PLAN
AOO/llONAL IIEO/A
TO AIA TCH !.· 1 HHERE AIEElS
NATIVE SO'L
FREEBOAR.
12• 11/N. Al)JACENT
TO LANOSCAPE
6 • AI/N. Al),J,4CEN T
TO HAROSCAPE
OIS1i4NCE FROII TOE
OF st.OPE TO LINER IN
GRAm LAYER
E
---- -- -0 40
VERR.011' SlRVCllJRE
ANO MAINTENANCE ACCESS
80 120
APRON FOR ENERCY
0/SSIPA 1E1? (EXTENO 2'
PAST TOE OF BASIN st.OPE}
160
SLIRFACE '°' 1-----<,__-t TG ELEV 'IYA1El? Q(JAL/TY ENOS AT Al 0/AIENSION
4•-5• OROP FROII
Cl/RB CVT TO APRON
SEE Cl/RB OPD.'/NG
OETAIL ON SIIEET 3 PROPOSE,~'°'
PER PLAN , EAN Ot/T TOP OF BASIN CREASE IN LINER I . . '-=---.----'4--l'-'"'--'-'='--1--+-+-------/('---,(---.--+=::..:....:::.::..:.. __ ..£.cc:::......:::...,=..::::::..:,,,----+----,,,-,
ABOI£ A I ELEVA 110N :I 1~ ~ ·-·-. ·-.. I 'i' I PLANllNG PER 3 •• -..~ _ ~ _ [ [ J , -
1
-LANDSCAPE _ _.J-~-
A 1 ELEVA nbN' ~ , .. , L L ' -l-"-1--1-FS~ELE-V \ ~ _ ~ 'y PL~N;. ,
yANGLE OF INR.VENCE
LINE FROII TOP OF
, / GRAm LAYER
-'.---3 "'-----,'i,"-------1
• , '1 '• I
/ -j
I ~ " --PERV'LAN' ---·
1~
-~ :1 I
ANGLE OF INR.VEM,,.-_ _...
;,__IIEOIA HflH l,f/N. 5--.....,,,.
IN/HR RL !RA 110N
RATE
, \ ,.,_ _-_ ~_:_--...,.1 --~-.:i
T · EXTENOEO Cl/RB ~ T,T-·~ UNER CAN BE
# ANGLE OF /NR.VENCE PLACED VNOER
NO TE: ALL BIOF/L !RA 110N AREAS HfLL
HAVE A SIGN POSlEO TO BE
VISIBLE AT ALL 111/ES
OETAIL
iVO OUMPINC" AT CATCH BASINS
NOTE: ALL CATCH BASINS HflH GRAlES
SHALL BE SlENC/LEO HflH CITY REC){J/REO
/lEII PER ABOVE OETAIL:
(OAS IIANVFACllJR/NG #Sf)O OR EC){J/VALENl}
INSTALLATION NOTES:
1. ALL HARDWARE, FLANGE, FRAME, SCREENS SHALL BE STAINLESS STEEL
2. OPTIONAL HYDROCARBON BOOM SHALL 8[ 2" DIAMETER.
J. Sff P[RFORMANCE R[PORTS IN MANUFACTURES SPECIFICATIONS.
4. OTHER STANDARD AND CUSTOM MODEL SIZES AVAILABLE -CONTACT
BIO CLEAN FOR MOR[ INFORMATION.
5. BASED ON 37% OPEN AREA.
6. CONSIDERS A SAFETY FACTOR OF 2.0.
7. CONSIDERS A LOCAL DEPRESSION PONDING DEPTH OF 6 INCHES.
8. STORAGE CAPACITY BASED ON THE BASKET HALF FULL
9. CONCRETE STRUCTURES SOLD S[PARAT[L~
BIO-CRATE-FULL
12-12-12
BIO-GRATE-FULL
18-18-12
BIO-GRATE-FULL
24-24-12
BIO-GRATE-FULL
24-40-12
810-GRAT[-FULL
24-24 -24
BIO-GRATE -FULL
24-40-24
BIO-GRATE-FULL
/.04
1.78
2.70
J.70
731
9.53
11.93
(CF)
1.24 0.15
2.79 O.JJ
4.96 0.59
6.35 0.88
4.96 1.22
6.35 1.82
7.14 2.73 NOT TO SCALE 36-36-24 ~----------~---~--~--_.....,. __ .....,. __ .....,. __ __ i PROPRIITARY AND CONRD[NTIAL: A
<:, TH£ 11'/R)f{/U,T/ON COMAi/i[[) IN mis OOCUMENTIS 7H£ SOJ.£ 8"10 ,-:;, Clean ~ N()Rmz:x:r =:: J/f if :'::kwclllfo ~~ ~
~ IN ANY I.WrN£R WJTH OtlT rH£ IW?IIJEN CONSENT OF FQfff£RRA. A forten'I Con,parlW'
GRATE INLET FILTER
FULL CAPTURE
STANDARD DETAIL
UNE FROII TOP Wfl
GRA m LA YER·ALL LOAOS
A , , tiNE FROII TOP OF Cl/RB ~----------------------------------------------------------------------~ :-___f GRA m LA >El?
IAlL fLOAOS SI/ALL
/JAIA St/All/ARY TABLE
VARIABLE OEPlH 2"-11/NVS--
GRA VEL STORAGE LA YER
(SEE TABLE FOR GRAVEL OEPlHS
6" PERFORAlEO PVC
VNOERORAIN PIPE VARIES
IIINIIIVII 3• AGGREGA 1E
BELOW VNOERORAIN
BIORL lli'A llON BASIN SECllON
T>PICAL SEC 110N
NOT TO SCALE
BIOF/LlRAllON HflH VNOERORAIN INSTALLAllON NOTES:
1. 8/0F/LlRAllON LAYER SOIL Al/)( SHALL BE 65% SANO, 10% SANOY LOAI.I, ANO 20%
COi/POST PLACEO IN 6' UFlS ANO COIIPACTEO HflH WAlER PRIOR TO !HE NEXT
UFT. INlllAL PERVEABIL/TY SHALL BE 8" PER HOUR (HflH AN ASS/JIIEO
STABILIZED PERIIEABIL/TY OF 5• PER HOUR)
2. GE01E)(11LE RLlER FABRIC TO BE INSTALLED ALONG !HE BOTTO/I OF !HE
BIOlREA!MENT BASIN & IN BET/£EN !HE GRAVEL & TOPSO'L LAYER SHALL BE A
IIIRAR HP570 OR EC){JIVALENT POROSITY.
3. IVPERIIEABLE IIEIIBRANE INSTALLED ALONG SIOES ANO BOTTO/I OF BIOlREA!MENT
BASIN SHALL BE 30 11/L /1/SC){JEEN PLASllC (OR EC){J/VALENl) & PLACEO
FI/LL-LENGlH FRO/I RN/SIi SVRFACE TO BOTTO/I OF !RENCH SECllON HflH TAPE
Hfi'APPEO AROLINO VNOERORAIN PIPE@ OL/ll.ET CONNECllON.
4. ALL GEOFABR/C INSTALLA llONS, RELO HEZO/NG OF SEAVS OF !HE IVPERIIEABLE
I/El/BRANES, ANO OBSERVAllON OF SO'L /1/)( PLACEIIENT SHALL BE St/BJECT TO
SPECIAL INSPECllON BY !HE ENGINEER OF RECORO PRIOR TO ACCEPTANCE OF !HE
FAC/LlllES
5. ENGINEER OF RECORD SHALL BE GIVEN 48 HOURS NOllCE FOR !HE INSPECllONS
OF !HE 8/0lREA!MENT BASIN INSTALLAllON (OR OlHER PREVIOUSLY ARRANGED
111/EFRAIIE}.
Wi BE!.·!
TO GRA~-.,---1r-----i , I (
1· -\. BE -r~; ;~~GE
-, )'ET ~\¥,,0~~ir'u"f,;;;?'r"="'u""7""~0"'=i;'a~i'ii5:?~=~u""7""~0"'~:;,,U~.;;;?iesl=~u""7""~0"'~~c~;...,~-::l-l---CLW.A YER AASIITO NO. 57 STONE
' '---~~~~-+--~. ·I ·I I BOTTO/I OF BASIN i
'flNAL SIZIN(i__()F LINER • ; -lf/N/11<1/A/i 6" Ol1J!E1El? 3• MINI GRAl1i. , If "I I I :rrrf'C.OIIPAClEO
PER SOIL ENGINlzyf l' JL I :J.D ~-PERFORAlEO VNOEJ? 0Ri4/N BELOW SO'L
REallf~~~ll~~,; • ' 1 I-... · /AIREl?AIEABLE-[/NER PERFORA 1EO PIPE
@PERFORATEO (30 AI/L AIIN. PONO UNER) EHECllVE AREA
PIPE R.011!.INE
i~ 'A TCH BASIN ~ ~ , , PER PLAN
A!,f f0 c1 f" ,
/'f3-!7l;-S-T01f._f 1• '; SCH 40 PVC A/ALE
r , ( 11 ADAPTER (lli1PxSoC)
~~•,,,,pvc"'==-F==U-4-rnl\ SCH 40 PVC lHREAOEO
DSLIBORAIN O ENO CAP (fPl}
Fr.i==~~~==~.LilJJ--OR/LL OR/RCE HOI.E AT ~ /I MIN. 1LJ {J} t R.011!.INE OF ENO CAP
J;-• (SIZE PER BIO-BASIN
\_AASIITO SLIAIAIARY 1i4BLE)
NO. 57STONE
ORIFICE OETAIL
NOT TO SCALE
8/fYlL IRA lla1/ BASIN 0£"4/L~
NOT TO SCALE
6" PVC PIPE PERFORA llON
LAYOUT OETAIL
NOT TO SCALE
DfESS\~ ~ D. Dq,,,&1 1~
No. 45629 o S8
/VI
OIIA 10
REC){JIREO PR0/1/0EO /IA)( TOP OF II/PER/I/OLIS PER/110//S 8/0F/L !RA 110N EFFECllVE HYOR0/100 RISER 81/P CLEANOLIT
01/A AREA AREA AREA 01/A ORA/NS TO TYPE OF Bl.IP OCV Bl.IP AREA VNOERORA/N Al A3 (CF) VOLVIIE' A2
(SOFT) (SOFl} (SOFT) (CF) (SOFl} R.OHf?A TE (CFS) (INCH) (INCH) (INCH)
OIIA-1 5,093 4,168 925 ORA/NS TO Bl.IP-A 8/0F/L IRA 110N 199 283 141 0.0135 9.75 15 9
OIIA-2 6,645 4,B44 1,801 ORA/NS TO BIIP-B 8/0F/L IRA 110N 239 313 498 0.0135 9 19 9
OIIA-3 34,369 30,507 3,B62 ORA/NS TO BIIP-C 8/0F/L IRA 110N 1,409 !,7B9 1,336 0.0285 9 15 9
OIIA-4 24,B24 20,764 4,060 ORA/NS TO BIIP-0 8/0F/L IRA 110N 981 1,3.N f,411 0.0303 9 15 9
OIIA-5 B,702 6,633 2,069 ORA/NS TO BIIP-E 8/0F/L IRA 110N 322 4.14 .508 0.0118 ,o 19 9
OIIA-6 9,481 7,149 2,331 ORA/NS TO BIIP-F 8/0F/L IRA 110N 351 487 389 0.0118 !7 19 9
OIIA-7 333 333 0 OE II/NII/IS N/,4 N/,4 N/,4 N/,4 N/,4 N/,4 N/,4 N/,4
TOTAL 89,#6 74,398 15,048 4,285
'PR0/110£0 8/0F/LlRAllON VOLVVE PER 8.3 81/P PERFORMANCE HORKSIIEET ROW 27 (VOLVVE RETAINED BY BIIP} + ROW 42 (PR0/1/0EO BIOF/LlRAllON VOLVIIE}
OA TE PREPARED: APRIL o.J; 2023
VERIFIED BY:
/1\
DAlE INlllAL DAlE INlllAL DAlE INlllAL
ENGINEER OF WORK REVISION DESCRIPTION OTHER APPROVAL CITY APPROVAL INSPECTOR DAlE
AIEOIA GRAVEL
C 0
(INCH) (INCH}
18 24
18 24
18 !8
18 24
18 !2
18 !2
N/,4 N/A
E
(FEEl}
3.25
4.25
3.25
3.25
4.25
4.25
N/,4
BOX RISER/
O/IERR.OW LOHER ORIRCE
SlRVCllJRE O/AAIE1ER (INCH)
SIZE (INCHES)
36)(36 0.5
24)(24 0.5625
24)(24 0.75
24)(36 0.75
24)(24 0.5
24)(24 0.5
N/,4 N/,4
I SH:ET I CITY OF CARLSBAD
ENGINEERING DEPARTMENT
SINGLE SHEET BMP
NORTH COAST MEO/CAL
PLAZA PHASE I & II
/VPERVEABLE
LINER?
/i:S
/i:S
/i:S
/i:S
/i:S
/i:S
N/,4
I SHE:Ts I
DWN BY: .IV PROJECT NO. DRAWING NO.
CHKD BY:
RVWD BY: SOP 15-23 496-!B