HomeMy WebLinkAboutSDP 16-07; OLIVENHAIN MUNICIPAL WATER DISTRICT; STORM WATER QUALITY MANAGEMENT PLAN; 2020-10-15E-35
CITY OF CARLSBAD
PRIORITY DEVELOPMENT PROJECT (PDP)
STORM WATER QUALITY MANAGEMENT PLAN (SWQMP)
FOR
“OLIVENHAIN MUNICIPAL WATER DISTRICT”
(NEW AND REMODELED ADMINISTRATION AND OPERATIONS FACILITIES)
SDP AMENDMENT 16-07
DWG 502-9A
GR2017-0019
ENGINEER OF WORK:
ARIC GNESA, P.E. C68339
PREPARED FOR:
OLIVENHAIN MUNICIPAL WATER DISTRICT
1966 OLIVENHAIN ROAD
ENCINITAS, CA 92024
(760) 753-6466
PREPARED BY:
INFRASTRUCTURE ENGINEERING CORPORATION
14271 DANIELSON STREET
POWAY, CA 92064
(858) 413-2400
DATE:October 15, 2020
AMENDED 10/15/20
E-35
Table of Contents
CERTIFICATION PAGE ............................................................................................................. 1
PROJECT VICINITY MAP.......................................................................................................... 2
FORM E-34 – STORM WATER STANDARD QUESTIONNAIRE ............................................... 3
SITE INFORMATION CHECKLIST ............................................................................................ 8
FORM E-36 – STANDARD PROJECT REQUIREMENT CHECKLIST ......................................21
SUMMARY OF PDP STRUCTURAL BMPS ..............................................................................25
ATTACHMENTS
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 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
ATTACHMENT 5: OPERATION AND MAINTENANCE PLAN
E-35 Page 1
CERTIFICATION PAGE
Project Name: OMWD Building Expansion
Project ID: SDP Amendment 16-07
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 San
Diego RWQCB 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.
C68839
Engineer of Work's Signature, P.E. Number
Aric Gnesa
Print Name
Infrastructure Engineering Corporation
Company
10/15/2020
Date
E-35 Page 2
PROJECT VICINITY MAP
E-35 Page 3
FORM E-34 – STORM WATER STANDARD QUESTIONNAIRE
E-34 Page 1 of 4 REV 02/16
Development Services
Land Development Engineering
1635 Faraday Avenue
760-602-2750
www.carlsbadca.gov
STORM WATER
STANDARDS
QUESTIONNAIRE
E-34
INSTRUCTIONS:
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 (BMP’s) 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 or be subject to ‘PRIORITY DEVELOPMENT
PROJECT’ (PDP) 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:
PROJECT ID:
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.
E-34 Page 2 of 4 REV. 02/16
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 5, mark the third 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;
b)Designed and constructed to be hydraulically disconnected from paved streets or roads;
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 5,
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.
E-34 Page 3 of 4 REV. 02/16
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 surface collectively over the entire project site and supports a street, road, highway
freeway or driveway? 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, check the first box stating “My project is a PDP …”
and complete applicant information.
If you answered “no” to all of the above questions, your project is a ‘STANDARD PROJECT’, ‘’Go to step 5, check the
second box stating “My project is a ‘STANDARD PROJECT’…” and complete applicant information.
E-34 Page 4 of 4 REV. 02/16
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 BMP’s required for PDP apply only to the creation or replacement of impervious
surface and not the entire development. Go to step 5, check the first box stating “My project is a PDP …” and complete
applicant information.
If you answered “no,” the structural BMP’s required for PDP apply to the entire development. Go to step 5, check the
check the first box stating “My project is a PDP …” and complete applicant information.
STEP 5
CHECK THE APPROPRIATE BOX AND COMPLETE APPLICANT INFORMATION
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) for submittal at time of application.
My project is a ‘STANDARD PROJECT’ OR EXEMPT from PDP and must only comply with ‘STANDARD PROJECT’
stormwater requirements of the BMP Manual. As part of these requirements, I will submit a “Standard Project
Requirement Checklist Form E-36” and incorporate low impact development strategies throughout my project.
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
Assessor’s Parcel Number(s):
___________________________________________
Applicant Name: Applicant Title:
_____________________________________________ _____________________________________________
Applicant Signature: Date:
_____________________________________________ _____________________________________________
*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.
This Box for City Use Only
City Concurrence: YES NO
By:
Date:
Project ID:
E-35 Page 8
SITE INFORMATION CHECKLIST
Project Summary Information
Project Name Olivenhain Municipal Water District – New and
Remodeled Operations & Administration
Facilities
Project ID SDP 16-07
Project Address 1966 Olivenhain Road
Encinitas, CA 92024
Assessor's Parcel Number(s) (APN(s)) 255-040-59 (formerly 255-031-03 and 255-040-
56, combined per Adj. Plat 16-06)
Project Watershed (Hydrologic Unit) Carlsbad 904
Parcel Area 10.54 Acres (459,053 SF)
Existing Impervious Area
(subset of Parcel Area) 5.30 Acres (230,930 Square Feet)
Area to be disturbed by the project
(Project Area) 2.37 Acres (103,049 Square Feet)
Project Proposed Impervious Area
(subset of Project Area) 1.40 Acres (61,115 Square Feet)
Project Proposed Pervious Area
(subset of Project Area) 0.96 Acres (41,934 Square Feet)
Note: Proposed Impervious Area + Proposed Pervious Area = Area to be Disturbed by the
Project.
This may be less than the Parcel Area.
E-35 Page 9
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:
Project site occurs on an existing developed parcel:
North of OMWD driveway: Existing OMWD administrative offices.
South of OMWD driveway: Existing OMWD operations facility; commercial lease on the
eastern one-third to agricultural food products store.
Existing Land Cover Includes (select all that apply):
☒Vegetative Cover
☒Non-Vegetated Pervious Areas
☒Impervious Areas
Description / Additional Information:
North of OMWD driveway: impervious pavements and building roofs with few landscape
areas.
South of OMWD driveway: impervious pavements and building roofs; pervious areas
are mostly non-vegetated.
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
E-35 Page 10
Existing Natural Hydrologic Features (select all that apply):
☐Watercourses
☐Seeps
☐Springs
☐Wetlands
☒None
Description / Additional Information:
The project site has no natural hydrologic features. The entire site has been graded previously
and is currently developed.
E-35 Page 11
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 project site is bounded by Olivenhain Road on the north, Rancho Santa Fe Road on the
east, Encinitas Creek on the south and private property on the west. The project site occurs on
two portions of a merged parcel owned by Olivenhain Municipal Water District (OMWD). Prior
to the lot merge, the parcels were divided by Old Olivenhain Road, which is now vacated as a
public road and serves as the OMWD driveway.
North of OMWD driveway: The topography slopes downward from northwest to southeast at
less than 5% slope, concentrating in the paved roadway (OMWD driveway) and flowing east to
the intersection of OMWD driveway and Rancho Santa Fe Road. There are no drainage
facilities along the OMWD driveway other than asphalt concrete berm and a Portland cement
cross gutter at the Rancho Santa Fe Road intersection. To the north and east, Olivenhain Road
and Rancho Santa Fe Road, respectively, are improved with curb and gutter and there is no off-
site runoff that enters the project site.
South of OMWD driveway: The topography slopes downward from northwest to southeast.
The existing, paved access road leading to the existing South Side Operations Building
captures the runoff from the western, approximately two-thirds of the south parcel and
directs it to two, existing bioretention basins. These basins are located on the west and
east sides of the existing Operations Building. The emergency overflow outlets from the
basins are piped via an underground storm drain to a headwall structure at the south
property line, east of the Operations Building. The discharge eventually surface flows to
Encinitas Creek.
The remaining, eastern, one-third of the south parcel drains south across the lot via
sheet flow toward the south property line. There are no existing storm drain
improvements on the eastern portion of the south parcel.
E-35 Page 12
Description of Proposed Site Development and Drainage Patterns
Project Description / Proposed Land Use and/or Activities:
The project will consist of the primary components:
Construction of a new building for administrative offices, a Board meeting room and
lobby;
Reconfiguration of existing paved areas for a new parking lot;
Construction of paving, curb and gutter improvements for the OMWD driveway (private);
Removal of existing paving, reconfiguration of existing landscape areas and construction
of new landscape improvements.
The project will be phased in order to provide temporary access to OMWD offices during
construction and for the construction of the east wing of the permanent building (Schedule B
Improvements). The building pad for the ultimate building configuration will be graded during
the first phase of the project.
Other project components will consist of:
Relocation of an existing emergency generator and electrical switchboard;
Relocation of existing cellular communication facilities and appurtenant electrical
services;
Renovation of the interior of existing buildings;
Demolition of an existing vehicle wash bay and above ground fueling station.
The existing land uses are commercial for administrative office spaces (north of OMWD
driveway) and commercial south of OMWD driveway. The proposed land uses will remain the
same as the existing land uses.
Construction of the project will result in an overall decrease in impervious cover, approximately
30,872 square feet (0.71 acres).
List/describe proposed impervious features of the project (e.g., buildings, roadways,
parking lots, courtyards, athletic courts, other impervious features):
building roofs;
walkways;
parking spaces and drive lanes;
street paving, new and replacement (OMWD driveway).
E-35 Page 13
List/describe proposed pervious features of the project (e.g., landscape areas):
landscaping around the proposed building improvements and where existing paving will
be removed;
permeable pavements in new or reconfigured parking areas;
permeable pavement in pedestrian walkway areas to replace existing impervious paving.
Does the project include grading and changes to site topography?
☒Yes
☐No
Description / Additional Information:
Grading is required to construct the new building pad for the building addition, for the
reconfiguration of existing parking areas, and for construction of the roundabout at the west end
of the OMWD driveway. The greatest change will be the placement of approximately 2 to 3 feet
of engineered fill (above existing grades) for the proposed building pad north of the existing
OMWD driveway and for construction of the driveway roundabout.
Does the project include changes to site drainage (e.g., installation of new storm water
conveyance systems)?
☒Yes
☐No
Description / Additional Information:
The project will not change the prevailing, existing drainage patterns or runoff concentration
points. The OMWD driveway will remain as a subarea boundary between the north and south
portions of the site.
The proposed drainage gradients will be flatter and flow paths will be longer than existing
conditions as a result of building pad construction. Surface runoff will be captured by proposed
inlets and piped to the proposed hydromodification basins and eventually to the existing runoff
concentration points. Runoff from existing roofs will be dispersed to landscaped areas. Runoff
from new roofs will be captured by proposed rain barrels before discharging as surface flow to
downstream hydromodification basins.
The existing sidewalk underdrain that discharges to Rancho Santa Fe Road 160 feet north of
OMWD driveway will remain. A new sidewalk underdrain and curb outlet is proposed at the
east end of OMWD driveway, north side, about 30 feet west of Rancho Santa Fe Road.
E-35 Page 14
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
E-35 Page 15
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):
Runoff from the project area concentrates at two locations:
Runoff from the north side of OMWD driveway concentrates at the intersection of the
OMWD driveway and Rancho Santa Fe Road and will comingle with off-site flows in
RSF Road. These flows will travel approximately 250 feet south along existing curb and
gutter to an existing curb inlet and public storm drain in RSF Road, then will ultimately
discharge on the north bank of Encinitas Creek.
Runoff from the western two-thirds of the south side of OMWD driveway flows in the
existing paved driveway leading to the South Side Operations Building and eventually
flows into two existing bioretention basins which discharge at the south property line.
Runoff from the eastern one-third of the south parcel which is not tributary to the existing
bioretention basins sheet flows over the south property line and onto the north overbank
area of Encinitas Creek.
From Encinitas Creek, flows continue west approximately 5,300 feet where they cross beneath
El Camino Real, then continue north approximately 8,600 feet where they enter Batiquitos
Lagoon and ultimately another 13,400 feet to the Pacific Ocean shoreline (total travel length of
5.2 miles)
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)/Stressor(s) TMDLs
Encinitas Creek Selenium None. TMDL req’d list, est.
completion: 2019
Encinitas Creek Toxicity None. TMDL req’d list, est.
completion: 2019
E-35 Page 16
Identification of Project Site Pollutants
Identify pollutants anticipated from the project site based on all proposed use(s) of the
site (see BMP Design Manual Appendix B.6):
Pollutant
Not Applicable to
the Project Site
Anticipated from the
Project Site
Also a Receiving
Water Pollutant of
Concern
Sediment ☐☒☐
Nutrients ☐☒☒
Heavy Metals ☐☒☒
Organic Compounds ☐☒☐
Trash & Debris ☐☒☐
Oxygen Demanding
Substances ☐☒☐
Oil & Grease ☐☒☒
Bacteria & Viruses ☒☐☐
Pesticides ☐☒☒
From the Carlsbad WMA Water Quality Improvement Plan, the Priority Water Quality Condition
identifies
toxicity for Encinitas Creek;
Indicator Bacteria for the Pacific Ocean Shoreline for the San Marcos Hydrologic Area
(at Cottonwood Creek, which is not in the flow path to the ocean).
Highest Priority Water Quality Conditions are not identified in the WQIP for Encinitas Creek,
Batiquitos Lagoon or the Pacific Ocean shoreline at Batiquitos Lagoon.
Receiving Water Pollutants of Concern, based on toxicity as a pollutant stressor, are identified
in the table above.
E-35 Page 17
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):
E-35 Page 18
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:
Based on the Google Earth kmz file available on Project Clean Water website, a potential critical
coarse sediment yield area (CCSYA) exists on the south side of OMWD driveway, but the area
is located outside of the grading/work limits. Onsite conveyance does not exist that would
deliver sediment from the potential CCSYA to Encinitas Creek because the potential CCSYA is
tributary to the two, existing bioretention basins that are located on the south side of OMWD
driveway. Refer to Attachment 2b.
E-35 Page 19
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.
POC 1: intersection of Rancho Santa Fe Road and OMWD driveway. Flows to Encinitas Creek
via existing, public storm drain in Rancho Santa Fe Road.
POC 2: along existing driveway to South Side Operations Building, near entrance to the
easterly, existing bioretention basin on the south parcel. Discharges at south parcel property
line via existing basin emergency outlet storm drain and eventually flows to Encinitas Creek.
Note: POC 1 and POC 2 eventually combine off-site in Encinitas Creek. The combined total,
post-project discharge is less than the pre-project discharge due to the removal of impervious
surfaces proposed by the project.
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)
The post-project peak discharge is less than the pre-project peak discharge.
E-35 Page 20
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.
Site constraints include Type C and D soils and limited hydraulic head (or fall) for partial
infiltration basin outlets. Borehole percolation testing performed at the site reveals variability in
observed infiltration rates, with the lowest observed infiltration rates in Type C soils. Infiltration
rates in mapped Type D soils were observed to be higher than in mapped Type C soils.
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-35 Page 21
FORM E-36 – STANDARD PROJECT REQUIREMENT CHECKLIST
E-36 Page 1 of 3 REV 02/16
Development Services
Land Development Engineering
1635 Faraday Avenue
760-602-2750
www.carlsbadca.gov
STANDARD PROJECT
REQUIREMENT
CHECKLIST
E-36
Project Information
Project Name:
Project ID:
DWG No. or Building Permit No.:
Source Control BMPs
All development projects must implement source control BMPs SC-1 through SC-6 where applicable and feasible.
See Chapter 4 and Appendix E.1 of the BMP Design Manual for information to implement source control BMPs
shown in this checklist.
Answer each category below pursuant to the following.
"Yes" means the project will implement the source control BMP as described in Chapter 4 and/or Appendix E.1
of the Model BMP Design Manual. Discussion/justification is not required.
"No" means the BMP is applicable to the project but it is not feasible to implement. Discussion/justification must
be provided.
"N/A" means the BMP is not applicable at the project site because the project does not include the feature that is
addressed by the BMP (e.g., the project has no outdoor materials storage areas). Discussion/justification may be
provided.
Source Control Requirement Applied?
SC-1 Prevention of Illicit Discharges into the MS4 Yes No N/A
Discussion/justification if SC-1 not implemented:
SC-2 Storm Drain Stenciling or Signage Yes No N/A
Discussion/justification if SC-2 not implemented:
SC-3 Protect Outdoor Materials Storage Areas from Rainfall, Run-On,
Runoff, and Wind Dispersal
Yes No N/A
Discussion/justification if SC-3 not implemented:
SC-4 Protect Materials Stored in Outdoor Work Areas from Rainfall, Run-On,
Runoff, and Wind Dispersal
Yes No N/A
Discussion/justification if SC-4 not implemented:
SC-5 Protect Trash Storage Areas from Rainfall, Run-On, Runoff, and Wind
Dispersal
Yes No N/A
Discussion/justification if SC-5 not implemented:
E-36 Page 2 of 3 REV. 02/16
Source Control Requirement Applied?
SC-6 Additional BMPs based on Potential Sources of Runoff Pollutants must
answer for each source listed below and identify additional BMPs. (See
Table in Appendix E.1 of BMP Manual for guidance).
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
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
For “Yes” answers, identify the additional BMP per Appendix E.1. Provide justification for “No” answers.
E-36 Page 3 of 3 REV. 02/16
Site Design BMPs
All development projects must implement site design BMPs SD-1 through SD-8 where applicable and feasible. See
Chapter 4 and Appendix E.2 thru E.6 of the BMP Design Manual for information to implement site design BMPs
shown in this checklist.
Answer each category below pursuant to the following.
"Yes" means the project will implement the site design BMPs as described in Chapter 4 and/or Appendix E.2
thru E.6 of the Model BMP Design Manual. Discussion / justification is not required.
"No" means the BMPs is applicable to the project but it is not feasible to implement. Discussion/justification must
be provided.
"N/A" means the BMPs is not applicable at the project site because the project does not include the feature that
is addressed by the BMPs (e.g., the project site has no existing natural areas to conserve).
Discussion/justification may be provided.
Site Design Requirement Applied?
SD-1 Maintain Natural Drainage Pathways and Hydrologic Features Yes No N/A
Discussion/justification if SD-1 not implemented:
SD-2 Conserve Natural Areas, Soils, and Vegetation Yes No N/A
Discussion/justification if SD-2 not implemented:
SD-3 Minimize Impervious Area Yes No N/A
Discussion/justification if SD-3 not implemented:
SD-4 Minimize Soil Compaction Yes No N/A
Discussion/justification if SD-4 not implemented:
SD-5 Impervious Area Dispersion Yes No N/A
Discussion/justification if SD-5 not implemented:
SD-6 Runoff Collection Yes No N/A
Discussion/justification if SD-6 not implemented:
SD-7 Landscaping with Native or Drought Tolerant Species Yes No N/A
Discussion/justification if SD-7 not implemented:
SD-8 Harvesting and Using Precipitation Yes No N/A
Discussion/justification if SD-8 not implemented:
E-35 Page 25
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).
E-35 Page 26
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.
Structural BMPs will be implemented for pollutant and hydromodification control based on the
site’s partial infiltration capability, as determined through borehole infiltration tests, and the
following.
•The site soils are mostly Group D with some Group C. However, borehole infiltration test
results indicate that the prior placement of fill may have influenced the infiltration tests as
the Group C soils in the eastern portion of the site have less infiltration capacity than
soils mapped as Group D. An average of the infiltration test results is used in
determining the design infiltration rate.
•Biofiltration with partial retention basins will be implemented where possible because of
the high pollutant removal efficiency for the receiving water pollutants of concern, the
need for hydromodification control, and for integration with landscape improvements.
Constraints include setbacks from building foundations or utilities. BMPs 1, 4, and 5 are
designed per the BMP sizing factors in the 2016 Model BMP Design Manual. BMP 6 was
recently added and is sized per the May 2018 Model BMP Design Manual as approved
by the City.
•Permeable pavements will be used to reduce imperviousness and the design capture
volume (DCV) for hydromodification control. They will be used in lieu of new impervious
pavements and to replace existing impervious pavements, where feasible. Permeable
pavements will provide some treatment via filtration through, and detention storage in the
aggregate sublayers. Permeable pavements will be used in parking spaces and in
courtyards and walkways and will be located in low-sediment generating drainage
management areas (DMAs) to reduce the potential for clogging. Permeable pavements
will include an underdrain (in Group C and D Soils) to reduce the potential for pavement
subgrade failure.
•Street tree BMPs (tree wells) will be used along the south side of OMWD (private drive)
to provide biofiltration where insufficient space exists for a biofiltration with partial
retention basin BMP. The design is a modified version of San Diego County Design
Standard GS-1.4, Tree Well with Open Tree Space.
•A cistern will intercept roof runoff from a new roof area and provide detention storage and
flow control ahead of downstream hydromodification basin.
Additional discussion is provided in the Structural BMP Summary Information sheets that follow.
E-35 Page 27
Structural BMP Summary Information
Structural BMP ID No.: 1
Dwg.: 502-9A Sheet No.: 14
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)
☒ Partial retention by biofiltration with partial retention (PR-1)
☐ Biofiltration (BF-1)
☐ 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
☐ 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
☐ Other (describe in discussion section below)
Discussion (as needed):
This basin will treat new pavement and landscape areas northwest of existing Building A in
DMA A2.
Existing building roof areas (DMA A2A) will be diverted to BMP 6.
E-35 Page 30
Structural BMP Summary Information
Structural BMP ID No.: 4
Dwg.: 502-9A Sheet No.: 15
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)
☒Partial retention by biofiltration with partial retention (PR-1)
☐Biofiltration (BF-1)
☐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
☐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
☐Other (describe in discussion section below)
Discussion (as needed):
This basin will treat new roof, pavement and landscape areas in DMAs A5, A6, A7, A10,
A10A, A10B, and A11. This basin has elevation constraints for the outlet and, therefore, 12
inches of biofiltration soil media is proposed. Existing Building “X” will be removed as part of
the project to allow space for construction of the basin.
E-35 Page 31
Structural BMP Summary Information
Structural BMP ID No.: 5
Dwg.: 502-9A Sheet No.: 13
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)
☒Partial retention by biofiltration with partial retention (PR-1)
☐Biofiltration (BF-1)
☐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
☐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
☐Other (describe in discussion section below)
Discussion (as needed):
This basin will treat new roof, pavement and landscape areas from DMAs B1B and B2, on the
east side of new Building D, and existing roof area DMA B1A.
E-35 Page 32
Structural BMP Summary Information
Structural BMP ID No.: 6
Dwg.: 502-9A Sheet No.: 16
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)
☒Partial retention by biofiltration with partial retention (PR-1)
☐Biofiltration (BF-1)
☐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
☐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
☐Other (describe in discussion section below)
Discussion (as needed):
This basin is designed per the May 2018 Model BMP Design Manual, per City approval due to
its recent addition to the project, and will provide hydromodification for:
•off-site DMA C4C (existing paving) to satisfy the hydromodification requirement for DMA
A8 which cannot be routed to a basin due to elevation constraints;
•existing roof areas in DMAs A2A and A4A to satisfy hydromodification requirements for
the new roof in DMA A2B (note: DMAs A2A and A4A currently drain to an existing storm
drain which will be intercepted and re-routed to BMP 6); and
•new pavements and landscaping in DMA C4A.
•DMAs A4 , captured from a cistern and routed to BMP 6
Existing parking lot AC paving in DMA C4C will be removed to allow space for construction of
the basin.
E-35 Page 33
Structural BMP Summary Information
Structural BMP ID No.: 31, 32, 33, 34
Dwg.: 502-9A Sheet No.: 15, 16
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)
☐Partial retention by biofiltration with partial retention (PR-1)
☒Biofiltration (BF-1)
☐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
☐Other (describe in discussion section below): Flow-thru treatment control
Purpose:
☒Pollutant control only
☐Hydromodification control only
☐Combined pollutant control and hydromodification control
☐Pre-treatment/forebay for another structural BMP
☐Other (describe in discussion section below)
Discussion (as needed):
Street trees in DMA A8 will provide pollutant control via biofiltration in the structural soil zone
and detention storage in the structural soil zone. The design is in general accordance with the
simple sizing method for infiltration BMPs and San Diego County Design Standard GS-1.04b
(modified). An underdrain will be installed beneath the structural soil layer per the landscape
architect’s recommendations.
This DMA has elevation constraints and street trees are considered the only feasible BMP along
the roadside of OMWD (private drive). Hydromodification for DMA A8 will be satisfied by BMP 6
which will provide hydromodification for an equivalent area of off-site pavement (DMA C4C) and
existing roof areas DMA A2A and DMA A4A.
E-35 Page 34
Structural BMP Summary Information
Structural BMP ID No.: 35
Dwg.: 502-9A Sheet No.: 14
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)
☐Partial retention by biofiltration with partial retention (PR-1)
☐Biofiltration (BF-1)
☐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
☒Other (describe in discussion section below): Cistern
Purpose:
☐Pollutant control only
☒Hydromodification control only
☐Combined pollutant control and hydromodification control
☐Pre-treatment/forebay for another structural BMP
☐Other (describe in discussion section below)
Discussion (as needed):
DMA A4 has limited space for a hydromodification basin. A cistern in DMA A4 will capture roof
runoff from DMA A4B and provide detention storage and flow control upstream of biofiltration
with partial retention basin BMP 6.
A1-1
ATTACHMENT 1 – BACKUP FOR PDP POLLUTANT CONTROL BMPS
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.3-1 of the BMP
Design Manual to complete Form I-7.
☒Included
☐Not included because the entire
project will use infiltration BMPs
Attachment 1d Form I-8, Categorization of Infiltration
Feasibility Condition (Required unless
the project will use harvest and use
BMPs)
Refer to Appendices C and D of the
BMP Design Manual to complete
Form I-8.
☒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 and E of the
BMP Design Manual for structural
pollutant control BMP design
guidelines
☒Included
A1-2
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)
A1-3
ATTACHMENT 1a – DMA EXHIBIT
APN 255-031-03APN 255-040-56APN 255-040-59APN 255-040-56RANC
H
O
S
A
N
T
A
F
E
R
O
A
DOMWD DRIVEWAYOLIVENHAIN ROADTO SOUTHSIDEOPERATIONS BUILDING
SOIL
T
Y
P
E
"
D
"
SOIL
T
Y
P
E
"
C
"NODE61NODE 28POC 1NODE 35POC 2POTENTIAL CRITICAL COARSE SEDIMENTYIELD AREA. SOURCE: PROJECT CLEANWATER, GOOGLE KMZ, 2016.(OFF-SITE EXISTAC PAVING)C2C1C2A6B3C3A3A2B4B1AA2AA4BA4CC4AC4BA8A11A5B2A7A4A10A9B1BA10AA10BA2BA4AA1C4CA4DA1ASCALE : 1" =20'-0" 502-9ALEGEND71TREATMENT CONTROLLOW IMPACT DESIGN (L.I.D.)SOURCE CONTROL20HYDROMODIFICATION & TREATMENT CONTROLHYDROMODIFICATION82XX5974**PERVIOUS CONC.PAVEMENTPERVIOUSINTERLOCKINGPAVERS2530222331SITE DESIGN345964*PRIOR TO THE RAINY SEASON (OCT 1 THROUGH APR 30)8081POROUS PAVING -GRASSSD-6BTC-102,350 SF.502-9A502-9A502-9A502-9A502-9A502-9A502-9A502-9A502-9A13-15SEMI-ANNUALLYSEMI-ANNUALLYSEMI-ANNUALLYSEMI-ANNUALLYSEMI-ANNUALLYQUARTERLYSD-6BTC-10SD-6BTC-101,706 SF.1,001 SF.BMP ID #BMP TYPESYMBOLSDBMP,CARLSBAD ORCASQA NO.QUANTITYDRAWING NO.SHEET NO.(S)INSPECTIONFREQUENCYMAINTENANCEFREQUENCY14, 1513BMP TABLEBIOFILTRATIONPR-1271 SF.QUARTERLYSEMI-ANNUALLY14WET VAULT(INCLUDES CISTERN)MP-50ROOF DRAIN TOLANDSCAPINGINLET FILTERVEGETATIVESWALEFT-1TC-30MP-52SD-1114 EA.7 EA.0 SF.ANNUALLYANNUALLYANNUALLYSEMI-ANNUALLY13-1513-15PERLANDSCAPE1313-15STREET TREESSD-14 EA.ANNUALLYANNUALLYSEMI-ANNUALLYANNUALLYANNUALLYANNUALLY1 EA.16 EA.GS-16SD-13NO DUMPINGDRAINS TO OCEANSTENCILSTRASHENCLOSURESDP 16-0712502-9ABIOFILTRATION3,282 SF.QUARTERLYSEMI-ANNUALLY15502-9ABIOFILTRATION676 SF.QUARTERLYSEMI-ANNUALLY13502-9ABIOFILTRATION1,885 SF.QUARTERLYSEMI-ANNUALLY16456502-9A14CISTERNHU-11 EA. / 660 GAL.ANNUALLYSEMI-ANNUALLY35PR-1PR-1PR-1
APN 255-031-03APN 255-040-56APN 255-040-59APN 255-040-56TO SOUTHS
IDEOPERATIONS
BU
ILD
INGNODE 35POC 2POTENTIAL CRITICAL COARSE SEDIMENTYIELD AREA. SOURCE: PROJECT CLEANWATER, GOOGLE KMZ, 2016.(OFF-SITE EXISTAC PAVING)C1C3A3A2A2AA4BA4CC4AC4BA4A9A10AA2BA4AC4CA4DSCALE : 1" =20'-0" 502-9ALEGENDSDP 16-0722
A1-6
ATTACHMENT 1b – TABULAR SUMMARY OF DMAs
DMA Type
Pervious
(sf)
Impervious
(sf)
Total Area
(sf)
Total Area
(ac) BMP
A2 Landscape, Concrete, Permeable Pavers 5,111 659 5,770 0.132 BMP 1, Biofilt. w/Partial Ret.
A2B Roof ‐ 239 239 0.005 Drains to landscape
A3 Permeable Paving, Concrete, Landscape 989 344 1,333 0.031 Self‐Retaining
A4 Landscape, Concrete 3,074 1,309 4,383 0.101 BMP 6, Biofilt. w/Partial Ret.
A4B Roof ‐ 1,070 1,070 0.025 BMP 6, Biofilt. w/Partial Ret., Cistern
A4D Permeable Paving, Concrete 486 322 808 0.019 Self‐Retaining
A5 Roof, Landscape, Concrete 3,025 3,038 6,064 0.139 BMP 4, Biofilt. w/Partial Ret.
A6 Roof, Landscape, Concrete 1,915 3,899 5,814 0.133 BMP 4, Biofilt. w/Partial Ret.
A7 AC, Landscape 189 9,937 10,125 0.232 BMP 4, Biofilt. w/Partial Ret.
A8 Permeable Paving, AC, Landscape 2,554 12,860 15,413 0.354 BMP 31‐34, Street Trees
A10 Roof, Pavement, Perm. Pavement, Landscape 1,897 2,931 4,828 0.111 BMP 4, Biofilt. w/Partial Ret.
A10A Roof ‐ 1,086 1,086 0.025 BMP 4, Biofilt. w/Partial Ret.
A11 Landscape 6,080 213 6,293 0.144 BMP 4, Biofilt. w/Partial Ret.
B1B Roof ‐ 1,887 1,887 0.043 BMP 5, Biofilt. w/Partial Ret.
B2 Roof, Landscape, Concrete 4,739 1,805 6,544 0.150 BMP 5, Biofilt. w/Partial Ret.
B3 Permeable Paving, AC, Landscape 2,971 6,907 9,878 0.227 BMP 22, Permeable Paving, Infiltration
B4 Landscape 2,580 26 2,606 0.060 Self‐Mitigating
C1 Landscape 999 ‐ 999 0.023 Self‐Mitigating
C2 Landscape 1,619 ‐ 1,619 0.037 Self‐Mitigating
C3 Paving, Landscape 729 7,546 8,276 0.190 Existing Bioretention Basin
C4A Paving, Landscape 979 4,951 5,930 0.136 BMP 6, Biofilt. w/Partial Ret.
C4B Paving, Landscape 1,998 86 2,084 0.048 BMP 6, Biofilt. w/Partial Ret.
41,934 61,115 103,049 2.37
DMA Type
Pervious
(sf)
Impervious
(sf)
Total Area
(sf)
Total Area
(ac)BMP
A1 Existing Roof ‐ 2,780 2,780 0.064 Existing Sand Filter
A1A Existing Landscape 2,314 ‐ 2,314 0.053 Existing Sand Filter
A2A Existing Roof ‐ 2,694 2,694 0.062 Drains to Basin 6
A4A Existing Roof ‐ 1,987 1,987 0.046 Drains to Basin 6
A4C Existing Concrete ‐ 342 342 0.008 Drains to landscape
A9 Existing Landscape 2,415 ‐ 2,415 0.055 Not Disturbed
A10B Existing Roof ‐ 1,451 1,451 0.033 BMP 4, Biofilt. w/Partial Ret.
B1A Existing Roof ‐ 1,589 1,589 0.036 BMP 5, Biofilt. w/Partial Ret.
C4C Existing AC ‐ 15,508 15,508 0.356 BMP 6, Biofilt. w/Partial Ret.
4,729 26,351 31,080 0.71
46,663 87,466 134,129 3.08
ATTACHMENT 1b ‐ DMA SUMMARY
Total Considered:
Subtotal:
DMAs in Proposed Limit of Work
DMAs ‐ Existing or Outside of Project Area
Subtotal:
Page 1 of 1
A1-8
ATTACHMENT 1c – FORM I-7, HARVEST AND USE FEASIBILITY SCREENING
CHECKLIST
Appendix I: Forms and Checklists
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.
[Provide a summary of calculations here]
3.Calculate the DCV using worksheet B-2.1.
DCV = __________ (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.
I-26 June 2015
A1-9
ATTACHMENT 1d – FORM I-8, CATEGORIZATION OF INFILTRATION FEASIBILITY
CONDITION
January 9, 2018 SCST No. 160105P3
Report No. 3
David Padilla, PE, QSD
Project Manager
Infrastructure Engineering Corporation
14271 Danielson Street
Poway, California 92064
Subject: REVIEW OF GRADING PLANS AND INFILTRATION ASSESSMENT
OLIVENHAIN MUNICIPAL WATER DISTRICT
NEW AND REMODELED OPERATIONS AND ADMINISTRATION FACILITIES
CARLSBAD, CALIFORNIA
References: 1. Infrastructure Engineering Corporation (2018), Grading Plans and Civil Details,
Olivenhain Municipal Water District, New and Remodeled Operations and
Administration Facilities, Drawing No. 502-9A, January 8.
2._______ (2018), City of Carlsbad, Priority Development Project (PDP), Storm Water
Quality Management Plan (SWQMP), Olivenhain Municipal Water District, New
and Remodeled Operations and Administration Facilities, January 2.
3.SCST, Inc. (2016), Geotechnical Investigation, Olivenhain Municipal Water District
(OMWD) Building D, 1966 Olivenhain Road, Encinitas, California, SCST No.
160105P3-1, March 3.
Dear Dave:
This letter confirms that SCST, Inc. reviewed the project grading plans and civil details and the
infiltration assessment in the SWQMP, References 1 and 2. In our opinion, the project plans and
details and the infiltration assessment forms I-8 and I-9 are prepared in accordance with the
recommendations contained in the project geotechnical report, Reference 3.
If you have any questions, please call me at (619) 280-4321.
Respectfully submitted,
SCST, INC.
6/30/19
Thomas B. Canady, PE 50057
Principal Engineer
(1)Addressee via e-mail: dpadilla@iecorporation.com
February 23, 2018 SCST No. 160105P3
Report No. 4
David Padilla, PE, QSD
Project Manager
Infrastructure Engineering Corporation
14271 Danielson Street
Poway, California 92064
Subject: REVIEW OF GRADING PLAN, FOUNDATION PLAN AND SPECIFICATIONS
OLIVENHAIN MUNICIPAL WATER DISTRICT
NEW AND REMODELED OPERATIONS AND ADMINISTRATION FACILITIES
CARLSBAD, CALIFORNIA
References: 1. Infrastructure Engineering Corporation (2018), Grading Plan, Olivenhain Municipal
Water District, New and Remodeled Operations and Administration Facilities,
Drawing No. 502-9A, January 8.
2.SCST, Inc. (2016), Geotechnical Investigation, Olivenhain Municipal Water District
Building D, 1966 Olivenhain Road, Encinitas, California, SCST No. 160105P3-1,
March 3.
3.Wynn Engineering (2017), Foundation Plan, Olivenhain Municipal Water District,
New and Remodeled Operations and Administration Facilities, 2nd Plan Check
Submittal, December 6.
Dear Dave:
This letter confirms that SCST, Inc. (SCST) reviewed the project grading plan, foundation plan and
specifications, References 1 and 3. In our opinion, the plans and specifications are prepared in
accordance with the recommendations contained in the project geotechnical report, Reference 2.
If you have any questions, please call me at (619) 280-4321.
Respectfully submitted,
SCST, INC.
6/30/19
Thomas B. Canady, PE 50057
Principal Engineer
(1)Addressee via e-mail: dpadilla@iecorporation.com
Appendix I: Forms and Checklists
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:
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability.
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:
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability.
I-27 June 2015
Appendix I: Forms and Checklists
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 Agency/Jurisdictions to substantiate findings
I-28 June 2015
Appendix I: Forms and Checklists
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:
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.
I-29 June 2015
Appendix I: Forms and Checklists
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:
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 Agency/Jurisdictions to substantiate findings
I-30 June 2015
A1-10
ATTACHMENT 1e – POLLUTANT CONTROL BMP DESIGN WORKSHEETS /
CALCULATIONS
DMA:A1
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 0.90 2,780 0.064 0.057
Paving (concrete, asphalt concrete)0.90 0 0.000 0.000
Unit Pavers (grouted)0.90 0 0.000 0.000
Decomposed Granite 0.30 0 0.000 0.000
Cobbles, Aggregate 0.30 0 0.000 0.000
Amended or Mulched Soils, Landscape 0.10 0 0.000 0.000
Permeable Pavement 0.10 0 0.000 0.000
Compacted Soil (e.g., unpaved parking)0.30 0 0.000 0.000
Natural (A Soil)0.10 0 0.000 0.000
Natural (B Soil)0.14 0 0.000 0.000
Natural (C Soil)0.23 0 0.000 0.000
Natural (D Soil)0.30 0 0.000 0.000
Σ = 2,780 0.064 0.057
Area Weighted C: 0.90
DMA:A1A
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 0.90 0 0.000 0.000
Paving (concrete, asphalt concrete)0.90 0 0.000 0.000
Unit Pavers (grouted)0.90 0 0.000 0.000
Decomposed Granite 0.30 0 0.000 0.000
Cobbles, Aggregate 0.30 0 0.000 0.000
Amended or Mulched Soils, Landscape 0.10 2,314 0.053 0.005
Permeable Pavement 0.10 0 0.000 0.000
Compacted Soil (e.g., unpaved parking)0.30 0 0.000 0.000
Natural (A Soil)0.10 0 0.000 0.000
Natural (B Soil)0.14 0 0.000 0.000
Natural (C Soil)0.23 0 0.000 0.000
Natural (D Soil)0.30 0 0.000 0.000
Σ = 2,314 0.053 0.005
Area Weighted C: 0.10
Area Weighted Runoff Factors for Pollutant Control
Reference: S.D. Model BMP Design Manual, Appendix B, Table B.1‐1
Surface
Surface
Existing roof; outside of project limits.
Existing landscape; outside of project limits.
Page 1 of 15
Area Weighted Runoff Factors for Pollutant Control
Reference: S.D. Model BMP Design Manual, Appendix B, Table B.1‐1
DMA:A2 & A2B
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 0.90 239 0.005 0.005
Paving (concrete, asphalt concrete)0.90 659 0.015 0.014
Unit Pavers (grouted)0.90 0 0.000 0.000
Decomposed Granite 0.30 0 0.000 0.000
Cobbles, Aggregate 0.30 0 0.000 0.000
Amended or Mulched Soils, Landscape 0.10 4,499 0.103 0.010
Permeable Pavement 0.10 612 0.014 0.001
Compacted Soil (e.g., unpaved parking)0.30 0 0.000 0.000
Natural (A Soil)0.10 0 0.000 0.000
Natural (B Soil)0.14 0 0.000 0.000
Natural (C Soil)0.23 0 0.000 0.000
Natural (D Soil)0.30 0 0.000 0.000
Σ = 6,009 0.138 0.030
Area Weighted C: 0.22
DMA:A2A
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 0.90 2,694 0.062 0.056
Paving (concrete, asphalt concrete)0.90 0 0.000 0.000
Unit Pavers (grouted)0.90 0 0.000 0.000
Decomposed Granite 0.30 0 0.000 0.000
Cobbles, Aggregate 0.30 0 0.000 0.000
Amended or Mulched Soils, Landscape 0.10 0 0.000 0.000
Permeable Pavement 0.10 0 0.000 0.000
Compacted Soil (e.g., unpaved parking)0.30 0 0.000 0.000
Natural (A Soil)0.10 0 0.000 0.000
Natural (B Soil)0.14 0 0.000 0.000
Natural (C Soil)0.23 0 0.000 0.000
Natural (D Soil)0.30 0 0.000 0.000
Σ = 2,694 0.062 0.056
Area Weighted C: 0.90
Existing roof; outside of project limits.
Surface
Surface
New roof, remodeled pavement and landscape.
Page 2 of 15
Area Weighted Runoff Factors for Pollutant Control
Reference: S.D. Model BMP Design Manual, Appendix B, Table B.1‐1
DMA:A3
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 0.90 0 0.000 0.000
Paving (concrete, asphalt concrete)0.90 344 0.008 0.007
Unit Pavers (grouted)0.90 0 0.000 0.000
Decomposed Granite 0.30 0 0.000 0.000
Cobbles, Aggregate 0.30 0 0.000 0.000
Amended or Mulched Soils, Landscape 0.10 25 0.001 0.000
Permeable Pavement 0.10 964 0.022 0.002
Compacted Soil (e.g., unpaved parking)0.30 0 0.000 0.000
Natural (A Soil)0.10 0 0.000 0.000
Natural (B Soil)0.14 0 0.000 0.000
Natural (C Soil)0.23 0 0.000 0.000
Natural (D Soil)0.30 0 0.000 0.000
Σ = 1,333 0.031 0.009
Area Weighted C: 0.31
DMA:A4 & A4B
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 0.90 1,070 0.025 0.022
Paving (concrete, asphalt concrete)0.90 1,309 0.030 0.027
Unit Pavers (grouted)0.90 0 0.000 0.000
Decomposed Granite 0.30 0 0.000 0.000
Cobbles, Aggregate 0.30 0 0.000 0.000
Amended or Mulched Soils, Landscape 0.10 3,074 0.071 0.007
Permeable Pavement 0.10 0 0.000 0.000
Compacted Soil (e.g., unpaved parking)0.30 0 0.000 0.000
Natural (A Soil)0.10 0 0.000 0.000
Natural (B Soil)0.14 0 0.000 0.000
Natural (C Soil)0.23 0 0.000 0.000
Natural (D Soil)0.30 0 0.000 0.000
Σ = 5,453 0.125 0.056
Area Weighted C: 0.45
New pervious pavement, concrete pavement, landscape.
New roof, remodeled pavement and landscape.
Surface
Surface
Page 3 of 15
Area Weighted Runoff Factors for Pollutant Control
Reference: S.D. Model BMP Design Manual, Appendix B, Table B.1‐1
DMA:A4A
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 0.90 1,987 0.046 0.041
Paving (concrete, asphalt concrete)0.90 0 0.000 0.000
Unit Pavers (grouted)0.90 0 0.000 0.000
Decomposed Granite 0.30 0 0.000 0.000
Cobbles, Aggregate 0.30 0 0.000 0.000
Amended or Mulched Soils, Landscape 0.10 0 0.000 0.000
Permeable Pavement 0.10 0 0.000 0.000
Compacted Soil (e.g., unpaved parking)0.30 0 0.000 0.000
Natural (A Soil)0.10 0 0.000 0.000
Natural (B Soil)0.14 0 0.000 0.000
Natural (C Soil)0.23 0 0.000 0.000
Natural (D Soil)0.30 0 0.000 0.000
Σ = 1,987 0.046 0.041
Area Weighted C: 0.90
DMA:A4C
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 0.90 0 0.000 0.000
Paving (concrete, asphalt concrete)0.90 342 0.008 0.007
Unit Pavers (grouted)0.90 0 0.000 0.000
Decomposed Granite 0.30 0 0.000 0.000
Cobbles, Aggregate 0.30 0 0.000 0.000
Amended or Mulched Soils, Landscape 0.10 0 0.000 0.000
Permeable Pavement 0.10 0 0.000 0.000
Compacted Soil (e.g., unpaved parking)0.30 0 0.000 0.000
Natural (A Soil)0.10 0 0.000 0.000
Natural (B Soil)0.14 0 0.000 0.000
Natural (C Soil)0.23 0 0.000 0.000
Natural (D Soil)0.30 0 0.000 0.000
Σ = 342 0.008 0.007
Area Weighted C: 0.90
Existing roof; outside of project limits.
Existing pavement; outside of project limits.
Surface
Surface
Page 4 of 15
Area Weighted Runoff Factors for Pollutant Control
Reference: S.D. Model BMP Design Manual, Appendix B, Table B.1‐1
DMA:A4D
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 0.90 0 0.000 0.000
Paving (concrete, asphalt concrete)0.90 322 0.007 0.007
Unit Pavers (grouted)0.90 0 0.000 0.000
Decomposed Granite 0.30 0 0.000 0.000
Cobbles, Aggregate 0.30 0 0.000 0.000
Amended or Mulched Soils, Landscape 0.10 0 0.000 0.000
Permeable Pavement 0.10 486 0.011 0.001
Compacted Soil (e.g., unpaved parking)0.30 0 0.000 0.000
Natural (A Soil)0.10 0 0.000 0.000
Natural (B Soil)0.14 0 0.000 0.000
Natural (C Soil)0.23 0 0.000 0.000
Natural (D Soil)0.30 0 0.000 0.000
Σ = 808 0.019 0.008
Area Weighted C: 0.42
DMA:A5
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 0.90 2,161 0.050 0.045
Paving (concrete, asphalt concrete)0.90 878 0.020 0.018
Unit Pavers (grouted)0.90 0 0.000 0.000
Decomposed Granite 0.30 0 0.000 0.000
Cobbles, Aggregate 0.30 0 0.000 0.000
Amended or Mulched Soils, Landscape 0.10 3,025 0.069 0.007
Permeable Pavement 0.10 0 0.000 0.000
Compacted Soil (e.g., unpaved parking)0.30 0 0.000 0.000
Natural (A Soil)0.10 0 0.000 0.000
Natural (B Soil)0.14 0 0.000 0.000
Natural (C Soil)0.23 0 0.000 0.000
Natural (D Soil)0.30 0 0.000 0.000
Σ = 6,064 0.139 0.070
Area Weighted C: 0.50
Surface
Surface
New pervious pavement and concrete pavement.
New roof, pavement and landscape.
Page 5 of 15
Area Weighted Runoff Factors for Pollutant Control
Reference: S.D. Model BMP Design Manual, Appendix B, Table B.1‐1
DMA:A6
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 0.90 2,672 0.061 0.055
Paving (concrete, asphalt concrete)0.90 1,227 0.028 0.025
Unit Pavers (grouted)0.90 0 0.000 0.000
Decomposed Granite 0.30 0 0.000 0.000
Cobbles, Aggregate 0.30 0 0.000 0.000
Amended or Mulched Soils, Landscape 0.10 1,915 0.044 0.004
Permeable Pavement 0.10 0 0.000 0.000
Compacted Soil (e.g., unpaved parking)0.30 0 0.000 0.000
Natural (A Soil)0.10 0 0.000 0.000
Natural (B Soil)0.14 0 0.000 0.000
Natural (C Soil)0.23 0 0.000 0.000
Natural (D Soil)0.30 0 0.000 0.000
Σ = 5,814 0.133 0.085
Area Weighted C: 0.64
DMA:A7
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 0.90 0 0.000 0.000
Paving (concrete, asphalt concrete)0.90 9,937 0.228 0.205
Unit Pavers (grouted)0.90 0 0.000 0.000
Decomposed Granite 0.30 0 0.000 0.000
Cobbles, Aggregate 0.30 0 0.000 0.000
Amended or Mulched Soils, Landscape 0.10 189 0.004 0.000
Permeable Pavement 0.10 0 0.000 0.000
Compacted Soil (e.g., unpaved parking)0.30 0 0.000 0.000
Natural (A Soil)0.10 0 0.000 0.000
Natural (B Soil)0.14 0 0.000 0.000
Natural (C Soil)0.23 0 0.000 0.000
Natural (D Soil)0.30 0 0.000 0.000
Σ = 10,125 0.232 0.206
Area Weighted C: 0.89
Surface
Surface
New roof, pavement and landscape.
New pavement and landscape.
Page 6 of 15
Area Weighted Runoff Factors for Pollutant Control
Reference: S.D. Model BMP Design Manual, Appendix B, Table B.1‐1
DMA:A8
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 0.90 0 0.000 0.000
Paving (concrete, asphalt concrete)0.90 12,860 0.295 0.266
Unit Pavers (grouted)0.90 0 0.000 0.000
Decomposed Granite 0.30 0 0.000 0.000
Cobbles, Aggregate 0.30 0 0.000 0.000
Amended or Mulched Soils, Landscape 0.10 1,946 0.045 0.004
Permeable Pavement 0.10 608 0.014 0.001
Compacted Soil (e.g., unpaved parking)0.30 0 0.000 0.000
Natural (A Soil)0.10 0 0.000 0.000
Natural (B Soil)0.14 0 0.000 0.000
Natural (C Soil)0.23 0 0.000 0.000
Natural (D Soil)0.30 0 0.000 0.000
Σ = 15,413 0.354 0.272
Area Weighted C: 0.77
DMA:A9
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 0.90 0 0.000 0.000
Paving (concrete, asphalt concrete)0.90 0 0.000 0.000
Unit Pavers (grouted)0.90 0 0.000 0.000
Decomposed Granite 0.30 0 0.000 0.000
Cobbles, Aggregate 0.30 0 0.000 0.000
Amended or Mulched Soils, Landscape 0.10 2,415 0.055 0.006
Permeable Pavement 0.10 0 0.000 0.000
Compacted Soil (e.g., unpaved parking)0.30 0 0.000 0.000
Natural (A Soil)0.10 0 0.000 0.000
Natural (B Soil)0.14 0 0.000 0.000
Natural (C Soil)0.23 0 0.000 0.000
Natural (D Soil)0.30 0 0.000 0.000
Σ = 2,415 0.055 0.006
Area Weighted C: 0.10
Existing landscape, outside of project limits.
Surface
Surface
New pavement and landscape.
Page 7 of 15
Area Weighted Runoff Factors for Pollutant Control
Reference: S.D. Model BMP Design Manual, Appendix B, Table B.1‐1
DMA:A10
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 0.90 2,879 0.066 0.059
Paving (concrete, asphalt concrete)0.90 52 0.001 0.001
Unit Pavers (grouted)0.90 0 0.000 0.000
Decomposed Granite 0.30 0 0.000 0.000
Cobbles, Aggregate 0.30 0 0.000 0.000
Amended or Mulched Soils, Landscape 0.10 1,449 0.033 0.003
Permeable Pavement 0.10 448 0.010 0.001
Compacted Soil (e.g., unpaved parking)0.30 0 0.000 0.000
Natural (A Soil)0.10 0 0.000 0.000
Natural (B Soil)0.14 0 0.000 0.000
Natural (C Soil)0.23 0 0.000 0.000
Natural (D Soil)0.30 0 0.000 0.000
Σ = 4,828 0.111 0.065
Area Weighted C: 0.59
DMA:A10A
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 0.90 1,086 0.025 0.022
Paving (concrete, asphalt concrete)0.90 0 0.000 0.000
Unit Pavers (grouted)0.90 0 0.000 0.000
Decomposed Granite 0.30 0 0.000 0.000
Cobbles, Aggregate 0.30 0 0.000 0.000
Amended or Mulched Soils, Landscape 0.10 0 0.000 0.000
Permeable Pavement 0.10 0 0.000 0.000
Compacted Soil (e.g., unpaved parking)0.30 0 0.000 0.000
Natural (A Soil)0.10 0 0.000 0.000
Natural (B Soil)0.14 0 0.000 0.000
Natural (C Soil)0.23 0 0.000 0.000
Natural (D Soil)0.30 0 0.000 0.000
Σ = 1,086 0.025 0.022
Area Weighted C: 0.90
New roof, pavement, permeable pavement, and landscape.
Remodeled roof.
Surface
Surface
Page 8 of 15
Area Weighted Runoff Factors for Pollutant Control
Reference: S.D. Model BMP Design Manual, Appendix B, Table B.1‐1
DMA:A10B
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 0.90 1,451 0.033 0.030
Paving (concrete, asphalt concrete)0.90 0 0.000 0.000
Unit Pavers (grouted)0.90 0 0.000 0.000
Decomposed Granite 0.30 0 0.000 0.000
Cobbles, Aggregate 0.30 0 0.000 0.000
Amended or Mulched Soils, Landscape 0.10 0 0.000 0.000
Permeable Pavement 0.10 0 0.000 0.000
Compacted Soil (e.g., unpaved parking)0.30 0 0.000 0.000
Natural (A Soil)0.10 0 0.000 0.000
Natural (B Soil)0.14 0 0.000 0.000
Natural (C Soil)0.23 0 0.000 0.000
Natural (D Soil)0.30 0 0.000 0.000
Σ = 1,451 0.033 0.030
Area Weighted C: 0.90
DMA:A11
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 0.90 0 0.000 0.000
Paving (concrete, asphalt concrete)0.90 213 0.005 0.004
Unit Pavers (grouted)0.90 0 0.000 0.000
Decomposed Granite 0.30 0 0.000 0.000
Cobbles, Aggregate 0.30 0 0.000 0.000
Amended or Mulched Soils, Landscape 0.10 6,080 0.140 0.014
Permeable Pavement 0.10 0 0.000 0.000
Compacted Soil (e.g., unpaved parking)0.30 0 0.000 0.000
Natural (A Soil)0.10 0 0.000 0.000
Natural (B Soil)0.14 0 0.000 0.000
Natural (C Soil)0.23 0 0.000 0.000
Natural (D Soil)0.30 0 0.000 0.000
Σ = 6,293 0.144 0.018
Area Weighted C: 0.13
Existing roof.
New pavement and landscape.
Surface
Surface
Page 9 of 15
Area Weighted Runoff Factors for Pollutant Control
Reference: S.D. Model BMP Design Manual, Appendix B, Table B.1‐1
DMA:B1A
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 0.90 1,589 0.036 0.033
Paving (concrete, asphalt concrete)0.90 0 0.000 0.000
Unit Pavers (grouted)0.90 0 0.000 0.000
Decomposed Granite 0.30 0 0.000 0.000
Cobbles, Aggregate 0.30 0 0.000 0.000
Amended or Mulched Soils, Landscape 0.10 0 0.000 0.000
Permeable Pavement 0.10 0 0.000 0.000
Compacted Soil (e.g., unpaved parking)0.30 0 0.000 0.000
Natural (A Soil)0.10 0 0.000 0.000
Natural (B Soil)0.14 0 0.000 0.000
Natural (C Soil)0.23 0 0.000 0.000
Natural (D Soil)0.30 0 0.000 0.000
Σ = 1,589 0.036 0.033
Area Weighted C: 0.90
DMA:B1B
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 0.90 1,887 0.043 0.039
Paving (concrete, asphalt concrete)0.90 0 0.000 0.000
Unit Pavers (grouted)0.90 0 0.000 0.000
Decomposed Granite 0.30 0 0.000 0.000
Cobbles, Aggregate 0.30 0 0.000 0.000
Amended or Mulched Soils, Landscape 0.10 0 0.000 0.000
Permeable Pavement 0.10 0 0.000 0.000
Compacted Soil (e.g., unpaved parking)0.30 0 0.000 0.000
Natural (A Soil)0.10 0 0.000 0.000
Natural (B Soil)0.14 0 0.000 0.000
Natural (C Soil)0.23 0 0.000 0.000
Natural (D Soil)0.30 0 0.000 0.000
Σ = 1,887 0.043 0.039
Area Weighted C: 0.90
Existing roof.
Surface
Surface
New roof.
Page 10 of 15
Area Weighted Runoff Factors for Pollutant Control
Reference: S.D. Model BMP Design Manual, Appendix B, Table B.1‐1
DMA:B2
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 0.90 201 0.005 0.004
Paving (concrete, asphalt concrete)0.77 1,604 0.037 0.028
Unit Pavers (grouted)0.90 0 0.000 0.000
Decomposed Granite 0.30 0 0.000 0.000
Cobbles, Aggregate 0.30 0 0.000 0.000
Amended or Mulched Soils, Landscape 0.10 4,359 0.100 0.010
Permeable Pavement 0.10 380 0.009 0.001
Compacted Soil (e.g., unpaved parking)0.30 0 0.000 0.000
Natural (A Soil)0.10 0 0.000 0.000
Natural (B Soil)0.14 0 0.000 0.000
Natural (C Soil)0.23 0 0.000 0.000
Natural (D Soil)0.30 0 0.000 0.000
Σ = 6,544 0.150 0.043
Area Weighted C: 0.29
DMA:B3
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 0.90 0 0.000 0.000
Paving (concrete, asphalt concrete)0.90 6,907 0.159 0.143
Unit Pavers (grouted)0.90 0 0.000 0.000
Decomposed Granite 0.30 0 0.000 0.000
Cobbles, Aggregate 0.30 0 0.000 0.000
Amended or Mulched Soils, Landscape 0.10 1,576 0.036 0.004
Permeable Pavement 0.10 1,395 0.032 0.003
Compacted Soil (e.g., unpaved parking)0.30 0 0.000 0.000
Natural (A Soil)0.10 0 0.000 0.000
Natural (B Soil)0.14 0 0.000 0.000
Natural (C Soil)0.23 0 0.000 0.000
Natural (D Soil)0.30 0 0.000 0.000
Σ = 9,878 0.227 0.150
Area Weighted C: 0.66
Surface
Surface
New roof, pavement, permeable pavement, and landscape. Impervious area adjustment factor
(dispersion) for paving.
New pavement, permeable pavement, and landscape.
Page 11 of 15
Area Weighted Runoff Factors for Pollutant Control
Reference: S.D. Model BMP Design Manual, Appendix B, Table B.1‐1
DMA:B4
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 0.90 0 0.000 0.000
Paving (concrete, asphalt concrete)0.90 26 0.001 0.001
Unit Pavers (grouted)0.90 0 0.000 0.000
Decomposed Granite 0.30 0 0.000 0.000
Cobbles, Aggregate 0.30 0 0.000 0.000
Amended or Mulched Soils, Landscape 0.10 2,580 0.059 0.006
Permeable Pavement 0.10 0 0.000 0.000
Compacted Soil (e.g., unpaved parking)0.30 0 0.000 0.000
Natural (A Soil)0.10 0 0.000 0.000
Natural (B Soil)0.14 0 0.000 0.000
Natural (C Soil)0.23 0 0.000 0.000
Natural (D Soil)0.30 0 0.000 0.000
Σ = 2,606 0.060 0.006
Area Weighted C: 0.11
DMA:C1
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 0.90 0 0.000 0.000
Paving (concrete, asphalt concrete)0.90 0 0.000 0.000
Unit Pavers (grouted)0.90 0 0.000 0.000
Decomposed Granite 0.30 0 0.000 0.000
Cobbles, Aggregate 0.30 0 0.000 0.000
Amended or Mulched Soils, Landscape 0.10 999 0.023 0.002
Permeable Pavement 0.10 0 0.000 0.000
Compacted Soil (e.g., unpaved parking)0.30 0 0.000 0.000
Natural (A Soil)0.10 0 0.000 0.000
Natural (B Soil)0.14 0 0.000 0.000
Natural (C Soil)0.23 0 0.000 0.000
Natural (D Soil)0.30 0 0.000 0.000
Σ = 999 0.023 0.002
Area Weighted C: 0.10
Surface
Surface
Existing and remodeled landscape.
New landscape.
Page 12 of 15
Area Weighted Runoff Factors for Pollutant Control
Reference: S.D. Model BMP Design Manual, Appendix B, Table B.1‐1
DMA:C2
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 0.90 0 0.000 0.000
Paving (concrete, asphalt concrete)0.90 0 0.000 0.000
Unit Pavers (grouted)0.90 0 0.000 0.000
Decomposed Granite 0.30 0 0.000 0.000
Cobbles, Aggregate 0.30 0 0.000 0.000
Amended or Mulched Soils, Landscape 0.10 1,619 0.037 0.004
Permeable Pavement 0.10 0 0.000 0.000
Compacted Soil (e.g., unpaved parking)0.30 0 0.000 0.000
Natural (A Soil)0.10 0 0.000 0.000
Natural (B Soil)0.14 0 0.000 0.000
Natural (C Soil)0.23 0 0.000 0.000
Natural (D Soil)0.30 0 0.000 0.000
Σ = 1,619 0.037 0.004
Area Weighted C: 0.10
DMA:C3
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 0.90 0 0.000 0.000
Paving (concrete, asphalt concrete)0.90 7,546 0.173 0.156
Unit Pavers (grouted)0.90 0 0.000 0.000
Decomposed Granite 0.30 0 0.000 0.000
Cobbles, Aggregate 0.30 0 0.000 0.000
Amended or Mulched Soils, Landscape 0.10 729 0.017 0.002
Permeable Pavement 0.10 0 0.000 0.000
Compacted Soil (e.g., unpaved parking)0.30 0 0.000 0.000
Natural (A Soil)0.10 0 0.000 0.000
Natural (B Soil)0.14 0 0.000 0.000
Natural (C Soil)0.23 0 0.000 0.000
Natural (D Soil)0.30 0 0.000 0.000
Σ = 8,276 0.190 0.158
Area Weighted C: 0.83
Surface
Surface
New landscape.
Remodeled pavement and landscape.
Page 13 of 15
Area Weighted Runoff Factors for Pollutant Control
Reference: S.D. Model BMP Design Manual, Appendix B, Table B.1‐1
DMA:C4A
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 0.90 0 0.000 0.000
Paving (concrete, asphalt concrete)0.90 4,951 0.114 0.102
Unit Pavers (grouted)0.90 0 0.000 0.000
Decomposed Granite 0.30 0 0.000 0.000
Cobbles, Aggregate 0.30 0 0.000 0.000
Amended or Mulched Soils, Landscape 0.10 979 0.022 0.002
Permeable Pavement 0.10 0 0.000 0.000
Compacted Soil (e.g., unpaved parking)0.30 0 0.000 0.000
Natural (A Soil)0.10 0 0.000 0.000
Natural (B Soil)0.14 0 0.000 0.000
Natural (C Soil)0.23 0 0.000 0.000
Natural (D Soil)0.30 0 0.000 0.000
Σ = 5,930 0.136 0.105
Area Weighted C: 0.77
DMA:C4B
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 0.90 0 0.000 0.000
Paving (concrete, asphalt concrete)0.90 86 0.002 0.002
Unit Pavers (grouted)0.90 0 0.000 0.000
Decomposed Granite 0.30 0 0.000 0.000
Cobbles, Aggregate 0.30 0 0.000 0.000
Amended or Mulched Soils, Landscape 0.10 1,998 0.046 0.005
Permeable Pavement 0.10 0 0.000 0.000
Compacted Soil (e.g., unpaved parking)0.30 0 0.000 0.000
Natural (A Soil)0.10 0 0.000 0.000
Natural (B Soil)0.14 0 0.000 0.000
Natural (C Soil)0.23 0 0.000 0.000
Natural (D Soil)0.30 0 0.000 0.000
Σ = 2,084 0.048 0.006
Area Weighted C: 0.13
Surface
Surface
Remodeled pavement and landscape.
BMP 6, biofiltration w/partial retention.
Page 14 of 15
Area Weighted Runoff Factors for Pollutant Control
Reference: S.D. Model BMP Design Manual, Appendix B, Table B.1‐1
DMA:C4C
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 0.90 0 0.000 0.000
Paving (concrete, asphalt concrete)0.90 15,508 0.356 0.320
Unit Pavers (grouted)0.90 0 0.000 0.000
Decomposed Granite 0.30 0 0.000 0.000
Cobbles, Aggregate 0.30 0 0.000 0.000
Amended or Mulched Soils, Landscape 0.10 0 0.000 0.000
Permeable Pavement 0.10 0 0.000 0.000
Compacted Soil (e.g., unpaved parking)0.30 0 0.000 0.000
Natural (A Soil)0.10 0 0.000 0.000
Natural (B Soil)0.14 0 0.000 0.000
Natural (C Soil)0.23 0 0.000 0.000
Natural (D Soil)0.30 0 0.000 0.000
Σ = 15,508 0.356 0.320
Area Weighted C: 0.90
Existing pavement; outside of project limits.
Surface
Page 15 of 15
Impervious Area Dispersion Adjustment Factors
Table B.2‐1: Impervious Area Adjustment Factors ‐ Dispersion
Pervious Area Ratio = Impervious Area/Pervious Area
Hydrologic Soil Group <=1 2 3 4
A 0.00 0.00 0.23 0.36
B 0.00 0.27 0.42 0.53
C 0.34 0.56 0.67 0.74
D 0.86 0.93 0.97 1.00
DMA
Soil
Group
Impervious
Area (sf)
Pervious
Area (sf)
Ratio:
Imp./Perv.
Impervious Area
Adjustment Factor
Adjusted Runoff
Factor
B2 D 1,805 4,739 0.38 0.86 0.77
Reference: S.D. Model BMP Design Manual, Appendix B, Table B.2‐1: Impervious Area Adjustment Factors that Account for
Dispersion.
Page 1 of 1
DMA:A1
d= 0.60 inches
A= 2,780 sf
0.064 acres
C= 0.90
TCV= 0 cubic‐feet
RCV= 0 cubic‐feet
DCV= 125 cubic‐feet
936 gallons
DMA:A1A
d= 0.60 inches
A= 2,314 sf
0.053 acres
C= 0.10
TCV= 0 cubic‐feet
RCV= 0 cubic‐feet
DCV= 12 cubic‐feet
87 gallons
DMA:A2 & A2B
d= 0.60 inches
A= 6,009 sf
0.138 acres
C= 0.22
TCV= 0 cubic‐feet
RCV= 0 cubic‐feet
DCV= 66 cubic‐feet
494 gallons
85th percentile 24‐hr storm depth from Figure B.1‐1
Area tributary to BMP (s)
Area weighted runoff factor (Appendix B.1.1 and B.2.1)
Street trees volume reduction
Rain barrels volume reduction
DCV = (3630 x C x d x A) – TCV ‐ RCV
Existing landscape area; outside of project limits; treated by existing sand media filter.
Worksheet B.2‐1: Design Capture Volume
Reference: S.D. Model BMP Design Manual, Appendix B, Section B.1 ‐ DCV
85th percentile 24‐hr storm depth from Figure B.1‐1
Area tributary to BMP (s)
Area weighted runoff factor (Appendix B.1.1 and B.2.1)
Street trees volume reduction
Rain barrels volume reduction
DCV = (3630 x C x d x A) – TCV ‐ RCV
Existing roof; outside of project limits; treated by existing sand media filter.
85th percentile 24‐hr storm depth from Figure B.1‐1
Area tributary to BMP (s)
Area weighted runoff factor (Appendix B.1.1 and B.2.1)
Street trees volume reduction
Rain barrels volume reduction
DCV = (3630 x C x d x A) – TCV ‐ RCV
New roof, remodeled pavement and landscape. Drains to BMP 1, biofiltration w/partial
retention.
Page 1 of 10
Worksheet B.2‐1: Design Capture Volume
Reference: S.D. Model BMP Design Manual, Appendix B, Section B.1 ‐ DCV
DMA:A2A
d= 0.60 inches
A= 2,694 sf
0.062 acres
C= 0.90
TCV= 0 cubic‐feet
RCV= 0 cubic‐feet
DCV= 121 cubic‐feet
907 gallons
DMA:A3
d= 0.60 inches
A= 1,333 sf
0.031 acres
C= 0.31
TCV= 0 cubic‐feet
RCV= 0 cubic‐feet
DCV= 21 cubic‐feet
155 gallons
DMA:A4 & A4B
d= 0.60 inches
A= 5,453 sf
0.125 acres
C= 0.45
TCV= 0 cubic‐feet
RCV= 0 cubic‐feet
DCV= 123 cubic‐feet
918 gallons
Area weighted runoff factor (Appendix B.1.1 and B.2.1)
Street trees volume reduction
Rain barrels volume reduction
Calculate DCV = (3630 x C x d x A) – TCV ‐ RCV
85th percentile 24‐hr storm depth from Figure B.1‐1
Area tributary to BMP (s)
Area weighted runoff factor (Appendix B.1.1 and B.2.1)
Street trees volume reduction
Rain barrels volume reduction
Calculate DCV = (3630 x C x d x A) – TCV ‐ RCV
85th percentile 24‐hr storm depth from Figure B.1‐1
Area tributary to BMP (s)
Existing roof; outside of project limits; drain to landscape.
New permeable pavement and sidewalk; self‐retaining DMA.
New roof; remodeled pavement and landscape. Drains to BMP 6, biofiltration w/partial
retention and cistern.
Area weighted runoff factor (Appendix B.1.1 and B.2.1)
85th percentile 24‐hr storm depth from Figure B.1‐1
Area tributary to BMP (s)
Street trees volume reduction
Rain barrels volume reduction
Calculate DCV = (3630 x C x d x A) – TCV ‐ RCV
Page 2 of 10
Worksheet B.2‐1: Design Capture Volume
Reference: S.D. Model BMP Design Manual, Appendix B, Section B.1 ‐ DCV
DMA:A4A
d= 0.60 inches
A= 1,987 sf
0.046 acres
C= 0.90
TCV= 0 cubic‐feet
RCV= 0 cubic‐feet
DCV= 89 cubic‐feet
669 gallons
DMA:A4C
d= 0.60 inches
A= 342 sf
0.008 acres
C= 0.90
TCV= 0 cubic‐feet
RCV= 0 cubic‐feet
DCV= 15 cubic‐feet
115 gallons
DMA:A4D
d= 0.60 inches
A= 808 sf
0.019 acres
C= 0.42
TCV= 0 cubic‐feet
RCV= 0 cubic‐feet
DCV= 17 cubic‐feet
127 gallons
Calculate DCV = (3630 x C x d x A) – TCV ‐ RCV
85th percentile 24‐hr storm depth from Figure B.1‐1
Area tributary to BMP (s)
New permeable pavement; self‐retaining DMA.
Existing pavement; outside of project limits; drain to landscape.
85th percentile 24‐hr storm depth from Figure B.1‐1
Area tributary to BMP (s)
Area weighted runoff factor (Appendix B.1.1 and B.2.1)
Street trees volume reduction
Rain barrels volume reduction
Calculate DCV = (3630 x C x d x A) – TCV ‐ RCV
Area weighted runoff factor (Appendix B.1.1 and B.2.1)
Street trees volume reduction
Rain barrels volume reduction
85th percentile 24‐hr storm depth from Figure B.1‐1
Area tributary to BMP (s)
Area weighted runoff factor (Appendix B.1.1 and B.2.1)
Street trees volume reduction
Rain barrels volume reduction
Existing roof; outside of project limits; drain to landscape.
Calculate DCV = (3630 x C x d x A) – TCV ‐ RCV
Page 3 of 10
Worksheet B.2‐1: Design Capture Volume
Reference: S.D. Model BMP Design Manual, Appendix B, Section B.1 ‐ DCV
DMA:A5
d= 0.60 inches
A= 6,064 sf
0.139 acres
C= 0.50
TCV= 0 cubic‐feet
RCV= 0 cubic‐feet
DCV= 152 cubic‐feet
1,134 gallons
DMA:A6
d= 0.60 inches
A= 5,814 sf
0.133 acres
C= 0.64
TCV= 0 cubic‐feet
RCV= 0 cubic‐feet
DCV= 186 cubic‐feet
1,392 gallons
DMA:A7
d= 0.60 inches
A= 10,125 sf
0.232 acres
C= 0.89
TCV= 0 cubic‐feet
RCV= 0 cubic‐feet
DCV= 451 cubic‐feet
3,370 gallons
Area tributary to BMP (s)
Area tributary to BMP (s)
Rain barrels volume reduction
Calculate DCV = (3630 x C x d x A) – TCV ‐ RCV
Rain barrels volume reduction
85th percentile 24‐hr storm depth from Figure B.1‐1
Area weighted runoff factor (Appendix B.1.1 and B.2.1)
Area weighted runoff factor (Appendix B.1.1 and B.2.1)
Street trees volume reduction
Rain barrels volume reduction
Calculate DCV = (3630 x C x d x A) – TCV ‐ RCV
New roof, pavement and landscape. Drains to BMP 4, biofiltration w/partial retention.
85th percentile 24‐hr storm depth from Figure B.1‐1
Street trees volume reduction
Calculate DCV = (3630 x C x d x A) – TCV ‐ RCV
85th percentile 24‐hr storm depth from Figure B.1‐1
Area tributary to BMP (s)
Area weighted runoff factor (Appendix B.1.1 and B.2.1)
Street trees volume reduction
New roof, pavement and landscape. Drains to BMP4, biofiltration w/partial retention.
Remodeled pavement and landscape. Drains to BMP 4, biofiltration w/partial retention.
Page 4 of 10
Worksheet B.2‐1: Design Capture Volume
Reference: S.D. Model BMP Design Manual, Appendix B, Section B.1 ‐ DCV
DMA:A8
d= 0.60 inches
A= 15,413 sf
0.354 acres
C= 0.77
TCV= 0 cubic‐feet
RCV= 0 cubic‐feet
DCV= 593 cubic‐feet
4,439 gallons
DMA:A9
d= 0.60 inches
A= 2,415 sf
0.055 acres
C= 0.10
TCV= 0 cubic‐feet
RCV= 0 cubic‐feet
DCV= 12 cubic‐feet
90 gallons
DMA:A10
d= 0.60 inches
A= 4,828 sf
0.111 acres
C= 0.59
TCV= 0 cubic‐feet
RCV= 0 cubic‐feet
DCV= 142 cubic‐feet
1,065 gallons
New roof, pavement and landscape. Drains to BMP 4, biofiltration w/partial retention.
Existing landscape; outside of project limits.
Rain barrels volume reduction
85th percentile 24‐hr storm depth from Figure B.1‐1
Area tributary to BMP (s)
Area tributary to BMP (s)
Area weighted runoff factor (Appendix B.1.1 and B.2.1)
Street trees volume reduction
Rain barrels volume reduction
Calculate DCV = (3630 x C x d x A) – TCV ‐ RCV
Calculate DCV = (3630 x C x d x A) – TCV ‐ RCV
Street trees volume reduction
Rain barrels volume reduction
Area weighted runoff factor (Appendix B.1.1 and B.2.1)
Area tributary to BMP (s)
Area weighted runoff factor (Appendix B.1.1 and B.2.1)
Street trees volume reduction
85th percentile 24‐hr storm depth from Figure B.1‐1
Calculate DCV = (3630 x C x d x A) – TCV ‐ RCV
Remodeled pavement and landscape. Drains to tree well BMPs 31 through 34. This DMA is
offset by management of offsite area DMA C4C.
85th percentile 24‐hr storm depth from Figure B.1‐1
Page 5 of 10
Worksheet B.2‐1: Design Capture Volume
Reference: S.D. Model BMP Design Manual, Appendix B, Section B.1 ‐ DCV
DMA:A10A
d= 0.60 inches
A= 1,086 sf
0.025 acres
C= 0.90
TCV= 0 cubic‐feet
RCV= 0 cubic‐feet
DCV= 49 cubic‐feet
366 gallons
DMA:A10B
d= 0.60 inches
A= 1,451 sf
0.033 acres
C= 0.90
TCV= 0 cubic‐feet
RCV= 0 cubic‐feet
DCV= 65 cubic‐feet
488 gallons
DMA:A11
d= 0.60 inches
A= 6,293 sf
0.144 acres
C= 0.13
TCV= 0 cubic‐feet
RCV= 0 cubic‐feet
DCV= 41 cubic‐feet
306 gallons
Calculate DCV = (3630 x C x d x A) – TCV ‐ RCV
Existing roof, drains to BMP 4, biofiltration w/partial retention.
New pavement and landscape. Drains to BMP 4, biofiltration w/partial retention.
85th percentile 24‐hr storm depth from Figure B.1‐1
Area tributary to BMP (s)
Area weighted runoff factor (Appendix B.1.1 and B.2.1)
Street trees volume reduction
Rain barrels volume reduction
Remodeled roof, drains to BMP 4, biofiltration w/partial retention.
Area weighted runoff factor (Appendix B.1.1 and B.2.1)
Street trees volume reduction
Rain barrels volume reduction
Calculate DCV = (3630 x C x d x A) – TCV ‐ RCV
85th percentile 24‐hr storm depth from Figure B.1‐1
Area tributary to BMP (s)
85th percentile 24‐hr storm depth from Figure B.1‐1
Area tributary to BMP (s)
Area weighted runoff factor (Appendix B.1.1 and B.2.1)
Street trees volume reduction
Rain barrels volume reduction
Calculate DCV = (3630 x C x d x A) – TCV ‐ RCV
Page 6 of 10
Worksheet B.2‐1: Design Capture Volume
Reference: S.D. Model BMP Design Manual, Appendix B, Section B.1 ‐ DCV
DMA:B1A
d= 0.60 inches
A= 1,589 sf
0.036 acres
C= 0.90
TCV= 0 cubic‐feet
RCV= 0 cubic‐feet
DCV= 72 cubic‐feet
535 gallons
DMA:B1B
d= 0.60 inches
A= 1,887 sf
0.043 acres
C= 0.90
TCV= 0 cubic‐feet
RCV= 0 cubic‐feet
DCV= 85 cubic‐feet
635 gallons
DMA:B2
d= 0.60 inches
A= 6,544 sf
0.150 acres
C= 0.29
TCV= 0 cubic‐feet
RCV= 0 cubic‐feet
DCV= 95 cubic‐feet
710 gallons
Rain barrels volume reduction
Calculate DCV = (3630 x C x d x A) – TCV ‐ RCV
Existing roof; outside of project limits. Drains to landscape.
New roof. Drains to BMP 5, biofiltration w/partial retention.
Rain barrels volume reduction
85th percentile 24‐hr storm depth from Figure B.1‐1
Street trees volume reduction
Rain barrels volume reduction
Calculate DCV = (3630 x C x d x A) – TCV ‐ RCV
Calculate DCV = (3630 x C x d x A) – TCV ‐ RCV
Area tributary to BMP (s)
Area weighted runoff factor (Appendix B.1.1 and B.2.1)
Street trees volume reduction
New roof, pavement and landscape. Drains to BMP 5, biofiltration w/partial retention.
Area weighted runoff factor (Appendix B.1.1 and B.2.1)
85th percentile 24‐hr storm depth from Figure B.1‐1
Area tributary to BMP (s)
Area weighted runoff factor (Appendix B.1.1 and B.2.1)
Street trees volume reduction
85th percentile 24‐hr storm depth from Figure B.1‐1
Area tributary to BMP (s)
Page 7 of 10
Worksheet B.2‐1: Design Capture Volume
Reference: S.D. Model BMP Design Manual, Appendix B, Section B.1 ‐ DCV
DMA:B3
d= 0.60 inches
A= 9,878 sf
0.227 acres
C= 0.66
TCV= 0 cubic‐feet
RCV= 0 cubic‐feet
DCV= 326 cubic‐feet
2,438 gallons
DMA:B4
d= 0.60 inches
A= 2,606 sf
0.060 acres
C= 0.11
TCV= 0 cubic‐feet
RCV= 0 cubic‐feet
DCV= 14 cubic‐feet
107 gallons
DMA:C1
d= 0.60 inches
A= 960 sf
0.022 acres
C= 0.10
TCV= 0 cubic‐feet
RCV= 0 cubic‐feet
DCV= 5 cubic‐feet
36 gallons
Landscape slope area, self‐mitigating DMA.
85th percentile 24‐hr storm depth from Figure B.1‐1
Area tributary to BMP (s)
Area weighted runoff factor (Appendix B.1.1 and B.2.1)
Street trees volume reduction
Rain barrels volume reduction
Calculate DCV = (3630 x C x d x A) – TCV ‐ RCV
Existing and remodeled landscape, self‐mitigating DMA.
85th percentile 24‐hr storm depth from Figure B.1‐1
Area tributary to BMP (s)
Area weighted runoff factor (Appendix B.1.1 and B.2.1)
Street trees volume reduction
Rain barrels volume reduction
Calculate DCV = (3630 x C x d x A) – TCV ‐ RCV
New pavement, permeable pavement, grass covered porous paving, and landscape.
Calculate DCV = (3630 x C x d x A) – TCV ‐ RCV
85th percentile 24‐hr storm depth from Figure B.1‐1
Area tributary to BMP (s)
Area weighted runoff factor (Appendix B.1.1 and B.2.1)
Street trees volume reduction
Rain barrels volume reduction
Page 8 of 10
Worksheet B.2‐1: Design Capture Volume
Reference: S.D. Model BMP Design Manual, Appendix B, Section B.1 ‐ DCV
DMA:C2
d= 0.60 inches
A= 1,619 sf
0.037 acres
C= 0.10
TCV= 0 cubic‐feet
RCV= 0 cubic‐feet
DCV= 8 cubic‐feet
61 gallons
DMA:C3
d= 0.60 inches
A= 8,276 sf
0.190 acres
C= 0.83
TCV= 0 cubic‐feet
RCV= 0 cubic‐feet
DCV= 343 cubic‐feet
2,569 gallons
DMA:C4A
d= 0.60 inches
A= 5,930 sf
0.136 acres
C= 0.77
TCV= 0 cubic‐feet
RCV= 0 cubic‐feet
DCV= 228 cubic‐feet
1,708 gallons
Remodeled pavement and landscape. Drains to BMP 6, biofiltration w/partial retention.
Rain barrels volume reduction
Calculate DCV = (3630 x C x d x A) – TCV ‐ RCV
Remodeled pavement and landscape, tributary to existing bioretention basin. This DMA is
offset by management of offsite area DMA C4C.
Remodeled landscape, self‐mitigating DMA.
85th percentile 24‐hr storm depth from Figure B.1‐1
Area tributary to BMP (s)
Area weighted runoff factor (Appendix B.1.1 and B.2.1)
Street trees volume reduction
Rain barrels volume reduction
Calculate DCV = (3630 x C x d x A) – TCV ‐ RCV
85th percentile 24‐hr storm depth from Figure B.1‐1
Area tributary to BMP (s)
Area weighted runoff factor (Appendix B.1.1 and B.2.1)
Street trees volume reduction
85th percentile 24‐hr storm depth from Figure B.1‐1
Area tributary to BMP (s)
Area weighted runoff factor (Appendix B.1.1 and B.2.1)
Street trees volume reduction
Rain barrels volume reduction
Calculate DCV = (3630 x C x d x A) – TCV ‐ RCV
Page 9 of 10
Worksheet B.2‐1: Design Capture Volume
Reference: S.D. Model BMP Design Manual, Appendix B, Section B.1 ‐ DCV
DMA:C4B
d= 0.60 inches
A= 4,343 sf
0.100 acres
C= 0.12
TCV= 0 cubic‐feet
RCV= 0 cubic‐feet
DCV= 26 cubic‐feet
195 gallons
DMA:C4C
d= 0.60 inches
A= 15,508 sf
0.356 acres
C= 0.90
TCV= 0 cubic‐feet
RCV= 0 cubic‐feet
DCV= 698 cubic‐feet
5,220 gallons
Existing pavement, outside of project limits. Drains to BMP 6 to offset DMA A8 and DMA C3
which cannot drain to BMPs.
BMP 6, biofiltration w/partial retention.
85th percentile 24‐hr storm depth from Figure B.1‐1
Area tributary to BMP (s)
Area weighted runoff factor (Appendix B.1.1 and B.2.1)
Street trees volume reduction
Rain barrels volume reduction
Calculate DCV = (3630 x C x d x A) – TCV ‐ RCV
85th percentile 24‐hr storm depth from Figure B.1‐1
Area tributary to BMP (s)
Area weighted runoff factor (Appendix B.1.1 and B.2.1)
Street trees volume reduction
Rain barrels volume reduction
Calculate DCV = (3630 x C x d x A) – TCV ‐ RCV
Page 10 of 10
BMP:1 DMA: A2 & A2B
1 66 cu. ft.
Partial Retention
2 0.40 in./hr.
3 36 hours
4 14 inches
5 0.40 in/in
6 36 inches
7 20 sq‐ft
8 0.10 in/in
9 27 cu. ft.
10 39 cu. ft.
BMP Parameters
11 9 inches
12 18 inches
13 13 inches
14 0.20 in/in
15 5 in./hr.
Baseline Calculations
16 6 hours
17 30 inches
18 18 inches
19 48 inches
Option 1 ‐ Biofilter 1.5 times the DCV
20 59 cu. ft.
21 15 sq‐ft
Option 2 ‐ Store 0.75 of remaining DCV in pores and ponding
22 29 cu. ft.
23 20 sq‐ft
Footprint of the BMP
24 6,009 sq‐ft
25 0.22
26 40 sq‐ft
27 40 sq‐ft
Total depth treated [Line 17 + Line 18]
Adjusted runoff factor for the drainage area (refer to Appendix B.1 and B.2)
Minimum BMP footprint [Line 24 x Line 25 x 0.03]
Footprint of the BMP = Maximum [(minimum Line 21, Line 23), Line 26]
Req'd biofiltered volume [1.5 x Line 10]
Req'd footprint [Line 20 / Line 19] x 12
Req'd storage volume (surface + pores), [0.75 x Line 10]
Req'd footprint [Line 22 / Line 18] x 12
Area draining to the BMP
Media thickness [18 inches minimum]
Media available pore space
Media filtration rate to be used for sizing
Allowable routing time for sizing
Depth filtered during storm [Line 15 x Line 16]
Note: Line 7 is used to estimate the amount of volume retained by the BMP. Update the assumed surface area in Line 7
until it is equivalent to the required biofiltration footprint (either Line 21 or Line 23).
Worksheet B.5‐1: Simple Sizing Method for Biofiltration BMPs
Reference: S.D. Model BMP Design Manual, Appendix B, Section B.5
Aggregate storage above underdrain invert (12 inches, typical). Use 0 inches for sizing
if the aggregate is not over the entire bottom suface area.
Depth of detention storage
[Line 11 + (Line 12 x Line 14) + (Line 13 x Line 5)]
Remaining DCV after implementing retention BMPs
Infiltration rate from Worksheet D.5‐1 if partial infiltration is feasible
Allowable drawdown time for aggregate storage below the underdrain
Depth of runoff that can be infiltrated [Line 2 x Line 3]
Aggregate pore space
Req'd depth of gravel below the underdrain [Line 4/Line 5]
Assumed surface area of the biofiltration BMP
Media retained pore space
Volume retained by BMP [[Line 4 + (Line 12 x Line 8)]/12] x Line 7
DCV that requires biofiltration [Line 1 ‐ Line 9]
Surface Ponding [6 inches minimum, 12 inches maximum]
Page 1 of 1
BMP:4 DMA: A10, A10A, A10B, A6, A7, A11, A5
1 1,086 cu. ft.
Partial Retention
2 0.40 in./hr.
3 36 hours
4 14 inches
5 0.40 in/in
6 36 inches
7 231 sq‐ft
8 0.10 in/in
9 301 cu. ft.
10 785 cu. ft.
BMP Parameters
11 9.00 inches
12 12.43 inches
13 13 inches
14 0.20 in/in
15 5 in./hr.
Baseline Calculations
16 6 hours
17 30 inches
18 17 inches
19 47 inches
Option 1 ‐ Biofilter 1.5 times the DCV
20 1,177 cu. ft.
21 303 sq‐ft
Option 2 ‐ Store 0.75 of remaining DCV in pores and ponding
22 589 cu. ft.
23 423 sq‐ft
Footprint of the BMP
24 35,661 sq‐ft
25 0.62
26 661 sq‐ft
27 661 sq‐ft
Depth of runoff that can be infiltrated [Line 2 x Line 3]
Worksheet B.5‐1: Simple Sizing Method for Biofiltration BMPs
Reference: S.D. Model BMP Design Manual, Appendix B, Section B.5
Remaining DCV after implementing retention BMPs
Infiltration rate from Worksheet D.5‐1 if partial infiltration is feasible
Allowable drawdown time for aggregate storage below the underdrain
Allowable routing time for sizing
Aggregate pore space
Req'd depth of gravel below the underdrain [Line 4/Line 5]
Assumed surface area of the biofiltration BMP
Media retained pore space
Volume retained by BMP [[Line 4 + (Line 12 x Line 8)]/12] x Line 7
DCV that requires biofiltration [Line 1 ‐ Line 9]
Surface Ponding [6 inches minimum, 12 inches maximum]
Media thickness [18 inches minimum]
Aggregate storage above underdrain invert (12 inches, typical). Use 0 inches for sizing
if the aggregate is not over the entire bottom suface area.
Media available pore space
Media filtration rate to be used for sizing
Note: Line 7 is used to estimate the amount of volume retained by the BMP. Update the assumed surface area in Line 7
until it is equivalent to the required biofiltration footprint (either Line 21 or Line 23).
Depth filtered during storm [Line 15 x Line 16]
Depth of detention storage
[Line 11 + (Line 12 x Line 14) + (Line 13 x Line 5)]
Total depth treated [Line 17 + Line 18]
Req'd biofiltered volume [1.5 x Line 10]
Req'd footprint [Line 20 / Line 19] x 12
Req'd storage volume (surface + pores), [0.75 x Line 10]
Req'd footprint [Line 22 / Line 18] x 12
Area draining to the BMP
Adjusted runoff factor for the drainage area (refer to Appendix B.1 and B.2)
Minimum BMP footprint [Line 24 x Line 25 x 0.03]
Footprint of the BMP = Maximum [(minimum Line 21, Line 23), Line 26]
Page 1 of 1
BMP:5 DMA: B1A, B1B, B2
1 252 cu. ft.
Partial Retention
2 0.40 in./hr.
3 36 hours
4 14 inches
5 0.40 in/in
6 36 inches
7 63 sq‐ft
8 0.10 in/in
9 85 cu. ft.
10 167 cu. ft.
BMP Parameters
11 8.25 inches
12 18 inches
13 13 inches
14 0.20 in/in
15 5 in./hr.
Baseline Calculations
16 6 hours
17 30 inches
18 17 inches
19 47 inches
Option 1 ‐ Biofilter 1.5 times the DCV
20 250 cu. ft.
21 64 sq‐ft
Option 2 ‐ Store 0.75 of remaining DCV in pores and ponding
22 125 cu. ft.
23 88 sq‐ft
Footprint of the BMP
24 10,020 sq‐ft
25 0.50
26 150 sq‐ft
27 150 sq‐ft
Depth of runoff that can be infiltrated [Line 2 x Line 3]
Worksheet B.5‐1: Simple Sizing Method for Biofiltration BMPs
Reference: S.D. Model BMP Design Manual, Appendix B, Section B.5
Remaining DCV after implementing retention BMPs
Infiltration rate from Worksheet D.5‐1 if partial infiltration is feasible
Allowable drawdown time for aggregate storage below the underdrain
Allowable routing time for sizing
Aggregate pore space
Req'd depth of gravel below the underdrain [Line 4/Line 5]
Assumed surface area of the biofiltration BMP
Media retained pore space
Volume retained by BMP [[Line 4 + (Line 12 x Line 8)]/12] x Line 7
DCV that requires biofiltration [Line 1 ‐ Line 9]
Surface Ponding [6 inches minimum, 12 inches maximum]
Media thickness [18 inches minimum]
Aggregate storage above underdrain invert (12 inches, typical). Use 0 inches for sizing
if the aggregate is not over the entire bottom suface area.
Media available pore space
Media filtration rate to be used for sizing
Note: Line 7 is used to estimate the amount of volume retained by the BMP. Update the assumed surface area in Line 7
until it is equivalent to the required biofiltration footprint (either Line 21 or Line 23).
Depth filtered during storm [Line 15 x Line 16]
Depth of detention storage
[Line 11 + (Line 12 x Line 14) + (Line 13 x Line 5)]
Total depth treated [Line 17 + Line 18]
Req'd biofiltered volume [1.5 x Line 10]
Req'd footprint [Line 20 / Line 19] x 12
Req'd storage volume (surface + pores), [0.75 x Line 10]
Req'd footprint [Line 22 / Line 18] x 12
Area draining to the BMP
Adjusted runoff factor for the drainage area (refer to Appendix B.1 and B.2)
Minimum BMP footprint [Line 24 x Line 25 x 0.03]
Footprint of the BMP = Maximum [(minimum Line 21, Line 23), Line 26]
Page 1 of 1
BMP:6 DMA: C4A, C4B, C4C, A2A, A4, A4A, A4B
1 1,285 cu. ft.
Partial Retention
2 0.51 in./hr.
3 36 hours
4 18 inches
5 0.40 in/in
6 46 inches
7 285 sq‐ft
8 0.10 in/in
9 479 cu. ft.
10 806 cu. ft.
BMP Parameters
11 14 inches
12 18 inches
13 15 inches
14 0.20 in/in
15 5 in./hr.
Baseline Calculations
16 6 hours
17 30 inches
18 24 inches
19 54 inches
Option 1 ‐ Biofilter 1.5 times the DCV
20 1,209 cu. ft.
21 271 sq‐ft
Option 2 ‐ Store 0.75 of remaining DCV in pores and ponding
22 605 cu. ft.
23 307 sq‐ft
Footprint of the BMP
24 33,656 sq‐ft
25 0.82
26 828 sq‐ft
27 828 sq‐ft
Note: Line 7 is used to estimate the amount of volume retained by the BMP. Update the assumed surface area in Line 7
until it is equivalent to the required biofiltration footprint (either Line 21 or Line 23).
Depth filtered during storm [Line 15 x Line 16]
Depth of detention storage
[Line 11 + (Line 12 x Line 14) + (Line 13 x Line 5)]
Total depth treated [Line 17 + Line 18]
Req'd biofiltered volume [1.5 x Line 10]
Req'd footprint [Line 20 / Line 19] x 12
Req'd storage volume (surface + pores), [0.75 x Line 10]
Req'd footprint [Line 22 / Line 18] x 12
Area draining to the BMP
Adjusted runoff factor for the drainage area (refer to Appendix B.1 and B.2)
Minimum BMP footprint [Line 24 x Line 25 x 0.03]
Footprint of the BMP = Maximum [(minimum Line 21, Line 23), Line 26]
Allowable routing time for sizing
Aggregate pore space
Req'd depth of gravel below the underdrain [Line 4/Line 5]
Assumed surface area of the biofiltration BMP
Media retained pore space
Volume retained by BMP [[Line 4 + (Line 12 x Line 8)]/12] x Line 7
DCV that requires biofiltration [Line 1 ‐ Line 9]
Surface Ponding [6 inches minimum, 12 inches maximum]
Media thickness [18 inches minimum]
Aggregate storage above underdrain invert (12 inches, typical). Use 0 inches for sizing
if the aggregate is not over the entire bottom suface area.
Media available pore space
Media filtration rate to be used for sizing
Depth of runoff that can be infiltrated [Line 2 x Line 3]
Worksheet B.5‐1: Simple Sizing Method for Biofiltration BMPs
Reference: S.D. Model BMP Design Manual, Appendix B, Section B.5
Remaining DCV after implementing retention BMPs
Infiltration rate from Worksheet D.5‐1 if partial infiltration is feasible
Allowable drawdown time for aggregate storage below the underdrain
Page 1 of 1
A2-1
ATTACHMENT 2 – BACKUP FOR PDP HYDROMODIFICATION CONTROL MEASURES
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
☐ 6.2.1 Verification of Geomorphic
Landscape Units Onsite
☐ 6.2.2 Downstream Systems
Sensitivity to Coarse Sediment
☐ 6.2.3 Optional Additional Analysis
of Potential Critical Coarse
Sediment Yield Areas Onsite
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
A2-2
ATTACHMENT 2a – HYDROMODIFICATION MANAGEMENT EXHIBIT
A2-3
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)
RAN
C
H
O
S
A
N
T
A
F
E
R
O
A
D E3E10E11E5E4E20E22E210.540.79E1543471030181611525020E80.070.840.190.770.230.900.190.460.140.610.290.900.490.840.150.82E10.110.66E120.050.68E60.150.90OLIVENHAIN ROADSOIL
T
Y
P
E
"
D
"
SOI
L
T
Y
P
E
"
C
"POC 1POC 2EXISTING SAND FILTER404821100-YR PRE-DEVELOPMENTFLOODPLAIN PER LOMR DATED OCT27, 2017, CASE NO. 17-09-2475PE20.050.8135649440.110.63EXISTING CONDITION HYDROMODIFICATION MANAGEMENT MAPOLIVENHAIN M.W.D. BUILDING D EXPANSION3-ALEGEND:0.110.66
RANCHO SANTA FE R
O
A
D E30E32E34E400.55XX2.56XX1.880.431.83XXOLIVENHAIN ROADSOIL TYPE "D"SOIL TYPE "C"SEEFIGURE3AEXISTINGBIORETENTION BASINEXISTINGBIORETENTION BASINNODE 50POC 2NODE 30POC 1100-YR PRE-DEVELOPMENTFLOODPLAIN PER LOMRDATED OCT 27, 2017, CASENO. 17-09-2475PLIMIT OF WORKSOIL TYPE "D"
SOIL TYPE "C"OLIVENHAIN M.W.D. BUILDING D EXPANSION3-BEXISTING CONDITION HYDROMODIFICATION MANAGEMENT MAPLEGEND:0.110.66
A11A8A5A6B2B3A7C3A3A2A4A10A1RANCH
O
S
A
N
T
A
F
E
R
O
A
DOLIVENHAIN ROADOLIVENHAIN ROADA9B4B1BB1AA10AA10BA2BA2AA4AA4BA4C
0.061.000.031.000.041.000.150.350.230.730.230.980.140.130.350.850.190.920.040.100.020.100.130.210.060.100.061.000.051.000.031.000.0051.000.030.330.0081.000.070.370.031.000.110.660.041.000.130.700.140.550.060.114143161727103763142155601520252628354957581961515245POC 2SOIL TYPE
"
D
"
SOIL TYPE
"
C
"100-YEAR POST-DEVELOPMENTFLOODPLAIN PER LOMRREQUEST REPORT DATEDNOVEMBER 2017100-YEAR PRE-DEVELOPMENTFLOODPLAIN PER LOMR DATED OCT 27,2017 , CASE NO. 17-09-2475PC4A0.140.850.020.30B518BMP 1BMP 5BMP 4C4C(OFF-SITE EXISTAC PAVING)C4BSLOPE AREAC2SLOPE AREAC2SLOPE AREAC1A1A0.050.100.361.00A4D0.020.520.050.14POC 13238394650370427175728030LEGEND:0.061.00PROPOSED CONDITION HYDROMODIFICATION MANAGEMENT MAPOLIVENHAIN M.W.D. BUILDING D EXPANSION4
A2-5
ATTACHMENT 2b – MANAGEMENT OF CRITICAL COARSE SEDIMENT YIELD AREAS
feetmeters1000300
A2-7
ATTACHMENT 2c – GEOMORPHIC ASSESSMENT OF RECEIVING CHANNELS
(Not Performed)
A2-8
ATTACHMENT 2d – FLOW CONTROL FACILITY DESIGN AND STRUCTURAL BMP
DRAWDOWN CALCULATIONS
BASINSBMP No. TypeReq'dArea(sf)Req'd V1 Storage(cf)Req'd V2 Storage(cf)Req'dStorageV1 + V2ProposedPond Area(sf)ProposedV1 Storage(cf)ProposedV2 Storage(cf)Proposed StorageV1 + V2% of Req'd StoragePondDepth(in)Freeboard(in)SoilMedia Depth (in)Agg.Storage Depth (in)Dia. Low Flow Orifice (in) Section 1Lined 21 191 159 115 274 224 120 177 297 109% 10 3 18 16 4/16Section DNo4 3,109 2,590 1,865 4,455 3,110 2,127 2,903 5,029 113% 10 3 12 18 10/16Section DNo5 547 455 328 783 604 340 550 890 114% 10 3 18 16 5/16Section DNo6 1,697 1,515 1,567 3,082 1,768 1,546 1,857 3,403 110% 12 3 18 18 3/4Section DNoNotes:8,594 9,620 112%1. Bioretention section per City of Carlsbad BMP Design Manual, Appendix E, Table E.20 PL Plant List. 2. No liner below the bottom of the aggregate storage layer.3. BMP 6 sized using 2018 Model BMP Design Manual sizing factors. Basins 1 through 5 sized using 2016 Model BMP Design Manual sizing factors.CISTERNSBMP No. TypeVolume(gal)Volume(cf) 535 660 880Notes:Total: 885. BMP 2: Required V1 ‐ Proposed V1 storage = 61 cf.CisternBiofiltration w/Partial Retention 3BMP SummaryBiofiltration w/Partial RetentionBiofiltration w/Partial RetentionBiofiltration w/Partial RetentionPage 1
Biofiltration Basin Area/Volume Calculations
BMP 1 BMP 4 BMP 5 BMP 6
Area ‐ Basin Top (sf)
(Includes Freeboard)271 3282 676 1885
Area ‐ Pond Surface (sf)
(Per BMP Sizing Sheets)224 3110 604 1768
Area ‐ Basin Bottom (sf)94 2561 385 1323
Area ‐ Bottom of Soil
Media (sf)126 2813 440 1464
Area ‐ Bottom of Gravel
(sf)65 2491 334 1257
Pond Depth (in)9.08 9 8.25 12
Soil Media Thick. (in)18 12.43 18 18
Agg. Layer Thick. (in)16 18 16 18
Freeboard (in)3 333
Porosity 0.40 0.40 0.40 0.40
Surface Volume, V1* (cf) 120 2127 340 1546
Subsurface Volume, V2*
(cf)177 2903 550 1857
Freeboard Volume (cf) 62 799 160 457
Volume ‐
Agg. Layer (cf)51 1591 206 816
Volume ‐
Soil Media (cf)126 1311 344 1041
Page 1
DMA:A1
Surface
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 1.00 2,780 0.064 0.064
Paving (concrete, asphalt concrete)1.00 0 0.000 0.000
Pervious Concrete 0.10 0 0.000 0.000
Porous Asphalt 0.10 0 0.000 0.000
Grouted Unit Pavers 1.00 0 0.000 0.000
Solid Unit Pavers on Agg. Base, 3/16" Joints 0.20 0 0.000 0.000
Crushed Aggregate 0.10 0 0.000 0.000
Turf Block 0.10 0 0.000 0.000
Amended or Mulched Soils 0.10 0 0.000 0.000
Landscape 0.10 0 0.000 0.000
Σ = 2,780 0.064 0.064
Area Weighted Runoff Factor: 1.00
DMA:A1A
Surface
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 1.00 0 0.000 0.000
Paving (concrete, asphalt concrete)1.00 0 0.000 0.000
Pervious Concrete 0.10 0 0.000 0.000
Porous Asphalt 0.10 0 0.000 0.000
Grouted Unit Pavers 1.00 0 0.000 0.000
Solid Unit Pavers on Agg. Base, 3/16" Joints 0.20 0 0.000 0.000
Crushed Aggregate 0.10 0 0.000 0.000
Turf Block 0.10 0 0.000 0.000
Amended or Mulched Soils 0.10 2,314 0.053 0.005
Landscape 0.10 0 0.000 0.000
Σ = 2,314 0.053 0.005
Area Weighted Runoff Factor: 0.10
Area Weighted Runoff Factor for Hydromodification Sizing Factor Method
Reference: S.D. Model BMP Design Manual, Appendix B, Table G.2‐1: Runoff Factors for Surfaces Draining to
BMPs for Hydromodification Sizing Factor Method
Existing landscape; outside of project limits.
Existing roof; outside of project limits.
Page 1 of 15
Area Weighted Runoff Factor for Hydromodification Sizing Factor Method
Reference: S.D. Model BMP Design Manual, Appendix B, Table G.2‐1: Runoff Factors for Surfaces Draining to
BMPs for Hydromodification Sizing Factor Method
DMA:A2, A2B
Surface
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 1.00 239 0.005 0.005
Paving (concrete, asphalt concrete)1.00 659 0.015 0.015
Pervious Concrete 0.10 0 0.000 0.000
Porous Asphalt 0.10 0 0.000 0.000
Grouted Unit Pavers 1.00 0 0.000 0.000
Solid Unit Pavers on Agg. Base, 3/16" Joints 0.20 612 0.014 0.003
Crushed Aggregate 0.10 0 0.000 0.000
Turf Block 0.10 0 0.000 0.000
Amended or Mulched Soils 0.10 0 0.000 0.000
Landscape 0.10 4,499 0.103 0.010
Σ = 6,009 0.138 0.034
Area Weighted Runoff Factor: 0.24
DMA:A2A
Surface
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 1.00 2,694 0.062 0.062
Paving (concrete, asphalt concrete)1.00 0 0.000 0.000
Pervious Concrete 0.10 0 0.000 0.000
Porous Asphalt 0.10 0 0.000 0.000
Grouted Unit Pavers 1.00 0 0.000 0.000
Solid Unit Pavers on Agg. Base, 3/16" Joints 0.20 0 0.000 0.000
Crushed Aggregate 0.10 0 0.000 0.000
Turf Block 0.10 0 0.000 0.000
Amended or Mulched Soils 0.10 0 0.000 0.000
Landscape 0.10 0 0.000 0.000
Σ = 2,694 0.062 0.062
Area Weighted Runoff Factor: 1.00
New roof, remodeled pavement and landscape.
Existing roof; outside of project limits.
Page 2 of 15
Area Weighted Runoff Factor for Hydromodification Sizing Factor Method
Reference: S.D. Model BMP Design Manual, Appendix B, Table G.2‐1: Runoff Factors for Surfaces Draining to
BMPs for Hydromodification Sizing Factor Method
DMA:A3
Surface
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 1.00 0 0.000 0.000
Paving (concrete, asphalt concrete)1.00 344 0.008 0.008
Pervious Concrete 0.10 964 0.022 0.002
Porous Asphalt 0.10 0 0.000 0.000
Grouted Unit Pavers 1.00 0 0.000 0.000
Solid Unit Pavers on Agg. Base, 3/16" Joints 0.20 0 0.000 0.000
Crushed Aggregate 0.10 0 0.000 0.000
Turf Block 0.10 0 0.000 0.000
Amended or Mulched Soils 0.10 0 0.000 0.000
Landscape 0.10 25 0.001 0.000
Σ = 1,333 0.031 0.010
Area Weighted Runoff Factor: 0.33
DMA:A4, A4B
Surface
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 1.00 1,070 0.025 0.025
Paving (concrete, asphalt concrete)1.00 1,309 0.030 0.030
Pervious Concrete 0.10 0 0.000 0.000
Porous Asphalt 0.10 0 0.000 0.000
Grouted Unit Pavers 1.00 0 0.000 0.000
Solid Unit Pavers on Agg. Base, 3/16" Joints 0.20 0 0.000 0.000
Crushed Aggregate 0.10 0 0.000 0.000
Turf Block 0.10 0 0.000 0.000
Amended or Mulched Soils 0.10 0 0.000 0.000
Landscape 0.10 3,074 0.071 0.007
Σ = 5,453 0.125 0.062
Area Weighted Runoff Factor: 0.49
New pervious pavement, concrete pavement, landscape. This DMA is offset by management of
existing area DMAs A1, A2A, A4A, A4C, A10B, B1A, C4C.
New roof, remodeled pavement and landscape.
Page 3 of 15
Area Weighted Runoff Factor for Hydromodification Sizing Factor Method
Reference: S.D. Model BMP Design Manual, Appendix B, Table G.2‐1: Runoff Factors for Surfaces Draining to
BMPs for Hydromodification Sizing Factor Method
DMA:A4A
Surface
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 1.00 1,987 0.046 0.046
Paving (concrete, asphalt concrete)1.00 0 0.000 0.000
Pervious Concrete 0.10 0 0.000 0.000
Porous Asphalt 0.10 0 0.000 0.000
Grouted Unit Pavers 1.00 0 0.000 0.000
Solid Unit Pavers on Agg. Base, 3/16" Joints 0.20 0 0.000 0.000
Crushed Aggregate 0.10 0 0.000 0.000
Turf Block 0.10 0 0.000 0.000
Amended or Mulched Soils 0.10 0 0.000 0.000
Landscape 0.10 0 0.000 0.000
Σ = 1,987 0.046 0.046
Area Weighted Runoff Factor: 1.00
DMA:A4C
Surface
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 1.00 0 0.000 0.000
Paving (concrete, asphalt concrete)1.00 342 0.008 0.008
Pervious Concrete 0.10 0 0.000 0.000
Porous Asphalt 0.10 0 0.000 0.000
Grouted Unit Pavers 1.00 0 0.000 0.000
Solid Unit Pavers on Agg. Base, 3/16" Joints 0.20 0 0.000 0.000
Crushed Aggregate 0.10 0 0.000 0.000
Turf Block 0.10 0 0.000 0.000
Amended or Mulched Soils 0.10 0 0.000 0.000
Landscape 0.10 0 0.000 0.000
Σ = 342 0.008 0.008
Area Weighted Runoff Factor: 1.00
Existing roof, outside of project limits.
Existing pavement, outside of project limits.
Page 4 of 15
Area Weighted Runoff Factor for Hydromodification Sizing Factor Method
Reference: S.D. Model BMP Design Manual, Appendix B, Table G.2‐1: Runoff Factors for Surfaces Draining to
BMPs for Hydromodification Sizing Factor Method
DMA:A4D
Surface
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 1.00 0 0.000 0.000
Paving (concrete, asphalt concrete)1.00 322 0.007 0.007
Pervious Concrete 0.10 0 0.000 0.000
Porous Asphalt 0.10 0 0.000 0.000
Grouted Unit Pavers 1.00 0 0.000 0.000
Solid Unit Pavers on Agg. Base, 3/16" Joints 0.20 486 0.011 0.002
Crushed Aggregate 0.10 0 0.000 0.000
Turf Block 0.10 0 0.000 0.000
Amended or Mulched Soils 0.10 0 0.000 0.000
Landscape 0.10 0 0.000 0.000
Σ = 808 0.019 0.010
Area Weighted Runoff Factor: 0.52
DMA:A5
Surface
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 1.00 2,161 0.050 0.050
Paving (concrete, asphalt concrete)1.00 878 0.020 0.020
Pervious Concrete 0.10 0 0.000 0.000
Porous Asphalt 0.10 0 0.000 0.000
Grouted Unit Pavers 1.00 0 0.000 0.000
Solid Unit Pavers on Agg. Base, 3/16" Joints 0.20 0 0.000 0.000
Crushed Aggregate 0.10 0 0.000 0.000
Turf Block 0.10 0 0.000 0.000
Amended or Mulched Soils 0.10 0 0.000 0.000
Landscape 0.10 3,025 0.069 0.007
Σ = 6,064 0.139 0.077
Area Weighted Runoff Factor: 0.55
New pervious pavement and concrete pavement. This DMA is offset by management of existing area
DMAs A1, A2A, A4A, A4C, A10B, B1A, C4C.
New roof, pavement and landscape.
Page 5 of 15
Area Weighted Runoff Factor for Hydromodification Sizing Factor Method
Reference: S.D. Model BMP Design Manual, Appendix B, Table G.2‐1: Runoff Factors for Surfaces Draining to
BMPs for Hydromodification Sizing Factor Method
DMA:A6
Surface
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 1.00 2,672 0.061 0.061
Paving (concrete, asphalt concrete)1.00 1,227 0.028 0.028
Pervious Concrete 0.10 0 0.000 0.000
Porous Asphalt 0.10 0 0.000 0.000
Grouted Unit Pavers 1.00 0 0.000 0.000
Solid Unit Pavers on Agg. Base, 3/16" Joints 0.20 0 0.000 0.000
Crushed Aggregate 0.10 0 0.000 0.000
Turf Block 0.10 0 0.000 0.000
Amended or Mulched Soils 0.10 0 0.000 0.000
Landscape 0.10 1,915 0.044 0.004
Σ = 5,814 0.133 0.094
Area Weighted Runoff Factor: 0.70
DMA:A7
Surface
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 1.00 0 0.000 0.000
Paving (concrete, asphalt concrete)1.00 9,937 0.228 0.228
Pervious Concrete 0.10 0 0.000 0.000
Porous Asphalt 0.10 0 0.000 0.000
Grouted Unit Pavers 1.00 0 0.000 0.000
Solid Unit Pavers on Agg. Base, 3/16" Joints 0.20 0 0.000 0.000
Crushed Aggregate 0.10 0 0.000 0.000
Turf Block 0.10 0 0.000 0.000
Amended or Mulched Soils 0.10 0 0.000 0.000
Landscape 0.10 189 0.004 0.000
Σ = 10,126 0.232 0.229
Area Weighted Runoff Factor: 0.98
New roof, pavement and landscape.
New pavement and landscape.
Page 6 of 15
Area Weighted Runoff Factor for Hydromodification Sizing Factor Method
Reference: S.D. Model BMP Design Manual, Appendix B, Table G.2‐1: Runoff Factors for Surfaces Draining to
BMPs for Hydromodification Sizing Factor Method
DMA:A8
Surface
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 1.00 0 0.000 0.000
Paving (concrete, asphalt concrete)1.00 12,860 0.295 0.295
Pervious Concrete 0.10 0 0.000 0.000
Porous Asphalt 0.10 0 0.000 0.000
Grouted Unit Pavers 1.00 0 0.000 0.000
Solid Unit Pavers on Agg. Base, 3/16" Joints 0.20 608 0.014 0.003
Crushed Aggregate 0.10 0 0.000 0.000
Turf Block 0.10 0 0.000 0.000
Amended or Mulched Soils 0.10 0 0.000 0.000
Landscape 0.10 1,946 0.045 0.004
Σ = 15,414 0.354 0.302
Area Weighted Runoff Factor: 0.85
DMA:A9
Surface
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 1.00 0 0.000 0.000
Paving (concrete, asphalt concrete)1.00 0 0.000 0.000
Pervious Concrete 0.10 0 0.000 0.000
Porous Asphalt 0.10 0 0.000 0.000
Grouted Unit Pavers 1.00 0 0.000 0.000
Solid Unit Pavers on Agg. Base, 3/16" Joints 0.20 0 0.000 0.000
Crushed Aggregate 0.10 0 0.000 0.000
Turf Block 0.10 0 0.000 0.000
Amended or Mulched Soils 0.10 0 0.000 0.000
Landscape 0.10 2,415 0.055 0.006
Σ = 2,415 0.055 0.006
Area Weighted Runoff Factor: 0.10
Reconfigured pavementt, new pavement and landscape. This DMA is offset by management of
existing area DMAs A1, A2A, A4A, A4C, A10B, B1A, C4C.
Existing landscape, outside of project limits.
Page 7 of 15
Area Weighted Runoff Factor for Hydromodification Sizing Factor Method
Reference: S.D. Model BMP Design Manual, Appendix B, Table G.2‐1: Runoff Factors for Surfaces Draining to
BMPs for Hydromodification Sizing Factor Method
DMA:A10
Surface
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 1.00 2,879 0.066 0.066
Paving (concrete, asphalt concrete)1.00 52 0.001 0.001
Pervious Concrete 0.10 0 0.000 0.000
Porous Asphalt 0.10 0 0.000 0.000
Grouted Unit Pavers 1.00 0 0.000 0.000
Solid Unit Pavers on Agg. Base, 3/16" Joints 0.20 448 0.010 0.002
Crushed Aggregate 0.10 0 0.000 0.000
Turf Block 0.10 0 0.000 0.000
Amended or Mulched Soils 0.10 0 0.000 0.000
Landscape 0.10 1,449 0.033 0.003
Σ = 4,828 0.111 0.073
Area Weighted Runoff Factor: 0.66
DMA:A10A
Surface
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 1.00 1,086 0.025 0.025
Paving (concrete, asphalt concrete)1.00 0 0.000 0.000
Pervious Concrete 0.10 0 0.000 0.000
Porous Asphalt 0.10 0 0.000 0.000
Grouted Unit Pavers `1.00 0 0.000 0.000
Solid Unit Pavers on Agg. Base, 3/16" Joints 0.20 0 0.000 0.000
Crushed Aggregate 0.10 0 0.000 0.000
Turf Block 0.10 0 0.000 0.000
Amended or Mulched Soils 0.10 0 0.000 0.000
Landscape 0.10 0 0.000 0.000
Σ = 1,086 0.025 0.025
Area Weighted Runoff Factor: 1.00
New roof, pavement, landscape.
Remodeled roof.
Page 8 of 15
Area Weighted Runoff Factor for Hydromodification Sizing Factor Method
Reference: S.D. Model BMP Design Manual, Appendix B, Table G.2‐1: Runoff Factors for Surfaces Draining to
BMPs for Hydromodification Sizing Factor Method
DMA:A10B
Surface
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 1.00 1,451 0.033 0.033
Paving (concrete, asphalt concrete)1.00 0 0.000 0.000
Pervious Concrete 0.10 0 0.000 0.000
Porous Asphalt 0.10 0 0.000 0.000
Grouted Unit Pavers 1.00 0 0.000 0.000
Solid Unit Pavers on Agg. Base, 3/16" Joints 0.20 0 0.000 0.000
Crushed Aggregate 0.10 0 0.000 0.000
Turf Block 0.10 0 0.000 0.000
Amended or Mulched Soils 0.10 0 0.000 0.000
Landscape 0.10 0 0.000 0.000
Σ = 1,451 0.033 0.033
Area Weighted Runoff Factor: 1.00
DMA:A11
Surface
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 1.00 0 0.000 0.000
Paving (concrete, asphalt concrete)1.00 213 0.005 0.005
Pervious Concrete 0.10 0 0.000 0.000
Porous Asphalt 0.10 0 0.000 0.000
Grouted Unit Pavers 1.00 0 0.000 0.000
Solid Unit Pavers on Agg. Base, 3/16" Joints 0.20 0 0.000 0.000
Crushed Aggregate 0.10 0 0.000 0.000
Turf Block 0.10 0 0.000 0.000
Amended or Mulched Soils 0.10 0 0.000 0.000
Landscape 0.10 6,080 0.140 0.014
Σ = 6,293 0.144 0.019
Area Weighted Runoff Factor: 0.13
Existing roof.
New pavement and landscape.
Page 9 of 15
Area Weighted Runoff Factor for Hydromodification Sizing Factor Method
Reference: S.D. Model BMP Design Manual, Appendix B, Table G.2‐1: Runoff Factors for Surfaces Draining to
BMPs for Hydromodification Sizing Factor Method
DMA:B1A
Surface
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 1.00 1,589 0.036 0.036
Paving (concrete, asphalt concrete)1.00 0 0.000 0.000
Pervious Concrete 0.10 0 0.000 0.000
Porous Asphalt 0.10 0 0.000 0.000
Grouted Unit Pavers 1.00 0 0.000 0.000
Solid Unit Pavers on Agg. Base, 3/16" Joints 0.20 0 0.000 0.000
Crushed Aggregate 0.10 0 0.000 0.000
Turf Block 0.10 0 0.000 0.000
Amended or Mulched Soils 0.10 0 0.000 0.000
Landscape 0.10 0 0.000 0.000
Σ = 1,589 0.036 0.036
Area Weighted Runoff Factor: 1.00
DMA:B1B
Surface
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 1.00 1,887 0.043 0.043
Paving (concrete, asphalt concrete)1.00 0 0.000 0.000
Pervious Concrete 0.10 0 0.000 0.000
Porous Asphalt 0.10 0 0.000 0.000
Grouted Unit Pavers 1.00 0 0.000 0.000
Solid Unit Pavers on Agg. Base, 3/16" Joints 0.20 0 0.000 0.000
Crushed Aggregate 0.10 0 0.000 0.000
Turf Block 0.10 0 0.000 0.000
Amended or Mulched Soils 0.10 0 0.000 0.000
Landscape 0.10 0 0.000 0.000
Σ = 1,887 0.043 0.043
Area Weighted Runoff Factor: 1.00
Existing roof.
New roof.
Page 10 of 15
Area Weighted Runoff Factor for Hydromodification Sizing Factor Method
Reference: S.D. Model BMP Design Manual, Appendix B, Table G.2‐1: Runoff Factors for Surfaces Draining to
BMPs for Hydromodification Sizing Factor Method
DMA:B2
Surface
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 1.00 201 0.005 0.005
Paving (concrete, asphalt concrete)1.00 1,604 0.037 0.037
Pervious Concrete 0.10 0 0.000 0.000
Porous Asphalt 0.10 0 0.000 0.000
Grouted Unit Pavers 1.00 0 0.000 0.000
Solid Unit Pavers on Agg. Base, 3/16" Joints 0.20 380 0.009 0.002
Crushed Aggregate 0.10 0 0.000 0.000
Turf Block 0.10 0 0.000 0.000
Amended or Mulched Soils 0.10 0 0.000 0.000
Landscape 0.10 4,359 0.100 0.010
Σ = 6,544 0.150 0.053
Area Weighted Runoff Factor: 0.35
DMA:B3
Surface
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 1.00 0 0.000 0.000
Paving (concrete, asphalt concrete)1.00 6,907 0.159 0.159
Pervious Concrete 0.10 1,395 0.032 0.003
Porous Asphalt 0.10 0 0.000 0.000
Grouted Unit Pavers 1.00 0 0.000 0.000
Solid Unit Pavers on Agg. Base, 3/16" Joints 0.20 0 0.000 0.000
Crushed Aggregate 0.10 0 0.000 0.000
Turf Block 0.10 0 0.000 0.000
Amended or Mulched Soils 0.10 0 0.000 0.000
Landscape 0.10 1,576 0.036 0.004
Σ = 9,878 0.227 0.165
Area Weighted Runoff Factor: 0.73
New roof, pavement, permeable pavement, landscape.
New pavement, permeable pavement, landscape. This DMA is offset by management of existing area
DMAs A1, A2A, A4A, A4C, A10B, B1A, C4C.
Page 11 of 15
Area Weighted Runoff Factor for Hydromodification Sizing Factor Method
Reference: S.D. Model BMP Design Manual, Appendix B, Table G.2‐1: Runoff Factors for Surfaces Draining to
BMPs for Hydromodification Sizing Factor Method
DMA:B4
Surface
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 1.00 0 0.000 0.000
Paving (concrete, asphalt concrete)1.00 26 0.001 0.001
Pervious Concrete 0.10 0 0.000 0.000
Porous Asphalt 0.10 0 0.000 0.000
Grouted Unit Pavers 1.00 0 0.000 0.000
Solid Unit Pavers on Agg. Base, 3/16" Joints 0.20 0 0.000 0.000
Crushed Aggregate 0.10 0 0.000 0.000
Turf Block 0.10 0 0.000 0.000
Amended or Mulched Soils 0.10 0 0.000 0.000
Landscape 0.10 2,580 0.059 0.006
Σ = 2,606 0.060 0.007
Area Weighted Runoff Factor: 0.11
DMA:C1
Surface
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 1.00 0 0.000 0.000
Paving (concrete, asphalt concrete)1.00 0 0.000 0.000
Pervious Concrete 0.10 0 0.000 0.000
Porous Asphalt 0.10 0 0.000 0.000
Grouted Unit Pavers 1.00 0 0.000 0.000
Solid Unit Pavers on Agg. Base, 3/16" Joints 0.20 0 0.000 0.000
Crushed Aggregate 0.10 0 0.000 0.000
Turf Block 0.10 0 0.000 0.000
Amended or Mulched Soils 0.10 0 0.000 0.000
Landscape 0.10 999 0.023 0.002
Σ = 999 0.023 0.002
Area Weighted Runoff Factor: 0.10
Existing and remodeled landscape.
New landscape.
Page 12 of 15
Area Weighted Runoff Factor for Hydromodification Sizing Factor Method
Reference: S.D. Model BMP Design Manual, Appendix B, Table G.2‐1: Runoff Factors for Surfaces Draining to
BMPs for Hydromodification Sizing Factor Method
DMA:C2
Surface
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 1.00 0 0.000 0.000
Paving (concrete, asphalt concrete)1.00 0 0.000 0.000
Pervious Concrete 0.10 0 0.000 0.000
Porous Asphalt 0.10 0 0.000 0.000
Grouted Unit Pavers 1.00 0 0.000 0.000
Solid Unit Pavers on Agg. Base, 3/16" Joints 0.20 0 0.000 0.000
Crushed Aggregate 0.10 0 0.000 0.000
Turf Block 0.10 0 0.000 0.000
Amended or Mulched Soils 0.10 0 0.000 0.000
Landscape 0.10 1,619 0.037 0.004
Σ = 1,619 0.037 0.004
Area Weighted Runoff Factor: 0.10
DMA:C3
Surface
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 1.00 0 0.000 0.000
Paving (concrete, asphalt concrete)1.00 7,546 0.173 0.173
Pervious Concrete 0.10 0 0.000 0.000
Porous Asphalt 0.10 0 0.000 0.000
Grouted Unit Pavers 1.00 0 0.000 0.000
Solid Unit Pavers on Agg. Base, 3/16" Joints 0.20 0 0.000 0.000
Crushed Aggregate 0.10 0 0.000 0.000
Turf Block 0.10 0 0.000 0.000
Amended or Mulched Soils 0.10 0 0.000 0.000
Landscape 0.10 729 0.017 0.002
Σ = 8,276 0.190 0.175
Area Weighted Runoff Factor: 0.92
New landscape.
Remodeled pavement and landscape. This DMA is offset by management of existing area DMAs A1,
A2A, A4A, A4C, A10B, B1A, C4C.
Page 13 of 15
Area Weighted Runoff Factor for Hydromodification Sizing Factor Method
Reference: S.D. Model BMP Design Manual, Appendix B, Table G.2‐1: Runoff Factors for Surfaces Draining to
BMPs for Hydromodification Sizing Factor Method
DMA:C4A
Surface
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 1.00 0 0.000 0.000
Paving (concrete, asphalt concrete)1.00 4,951 0.114 0.114
Pervious Concrete 0.10 0 0.000 0.000
Porous Asphalt 0.10 0 0.000 0.000
Grouted Unit Pavers 1.00 0 0.000 0.000
Solid Unit Pavers on Agg. Base, 3/16" Joints 0.20 0 0.000 0.000
Crushed Aggregate 0.10 0 0.000 0.000
Turf Block 0.10 0 0.000 0.000
Amended or Mulched Soils 0.10 0 0.000 0.000
Landscape 0.10 979 0.022 0.002
Σ = 5,930 0.136 0.116
Area Weighted Runoff Factor: 0.85
DMA:C4B
Surface
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 1.00 0 0.000 0.000
Paving (concrete, asphalt concrete)1.00 86 0.002 0.002
Pervious Concrete 0.10 0 0.000 0.000
Porous Asphalt 0.10 0 0.000 0.000
Grouted Unit Pavers 1.00 0 0.000 0.000
Solid Unit Pavers on Agg. Base, 3/16" Joints 0.20 0 0.000 0.000
Crushed Aggregate 0.10 0 0.000 0.000
Turf Block 0.10 0 0.000 0.000
Amended or Mulched Soils 0.10 0 0.000 0.000
Landscape 0.10 1,998 0.046 0.005
Σ = 2,084 0.048 0.007
Area Weighted Runoff Factor: 0.14
Remodeled pavement and landscape.
BMP 6.
Page 14 of 15
Area Weighted Runoff Factor for Hydromodification Sizing Factor Method
Reference: S.D. Model BMP Design Manual, Appendix B, Table G.2‐1: Runoff Factors for Surfaces Draining to
BMPs for Hydromodification Sizing Factor Method
DMA:C4C
Surface
Runoff
Factor
Area
(sf)
Area
(acres)C*A
Roof 1.00 0 0.000 0.000
Paving (concrete, asphalt concrete)1.00 15,508 0.356 0.356
Pervious Concrete 0.10 0 0.000 0.000
Porous Asphalt 0.10 0 0.000 0.000
Grouted Unit Pavers 1.00 0 0.000 0.000
Solid Unit Pavers on Agg. Base, 3/16" Joints 0.20 0 0.000 0.000
Crushed Aggregate 0.10 0 0.000 0.000
Turf Block 0.10 0 0.000 0.000
Amended or Mulched Soils 0.10 0 0.000 0.000
Landscape 0.10 0 0.000 0.000
Σ = 15,508 0.356 0.356
Area Weighted Runoff Factor: 1.00
Existing pavement, outside of project limits.
Page 15 of 15
Worksheet G.2‐1: Sizing Factor WorksheetSite InformationProject Name: Hydrologic Unit:Project Applicant: Rain Gauge:Jurisdiction: Total Project Area (sf):Assessor’s Parcel No.: Low Flow Threshold (*Q2):BMP Name: BMP Type:Areas Draining to BMP Sizing Factors Minimum BMP SizeArea (sf) Soil TypePre‐ProjectSlopeRunoff Factor (From Table G.2‐1)Surface AreaSurfaceVolumeSubsurfaceVolumeSurfaceArea(sf)SurfaceVolume(cf)SubsurfaceVolume(cf)A2‐Pave 659 D flat concrete 1.00 0.1300 0.1083 0.078086 71 51 A2‐LS 4,499 D flat landscape 0.10 0.1300 0.1083 0.078058 49 35 A2‐Perm 612 D flat permeable pavement 0.20 0.1300 0.1083 0.078016 13 10 ‐ ‐ ‐ A2B‐Roof 239 D flat roof 1.00 0.1300 0.1083 0.078031 26 19 ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ Total DMA Area: 6,009 Min. BMP Size: 191 159 115 Proposed BMP Size: 224 133 146 Table G.2‐2: Unit Runoff Ratios Head on Low Flow Orifice (ft) Low Flow Orifice SizingUnit Runoff Ratio, Q2: 0.175cfs/ac Biofiltration w/Partial Retention, Biofiltration, Biofiltration w/Liner: 1.50 Low Flow Threshold (cfs): 0.0024Unit Runoff Ratio, Q10: 0.434cfs/ac Cistern, orifice head equal to 7/8 * cistern height: ‐ Max. Orifice Area (sq in): 0.0589Pre‐Dev. Q2: 0.024 cfsMax. Orifice Dia. (in): 0.274Pre‐Dev. Q10: 0.060 cfsMinimum 1/4" diameter, increment of 1/16": Proposed Orifice Dia. (in):0.2500255‐040‐59BMP 1DMA Name Post Project Surface Type0.1Biofiltration w/Partial RetentionOMWD New & Remodeled Ops. & Admin.OMWDCarlsbadCarlsbadOceanside103,050Page 1
Project Name: Hydrologic Unit:Project Applicant: Rain Gauge:Jurisdiction: Total Project Area:Parcel (APN): Low Flow Threshold:BMP Name BMP Type:Rain GaugeQ2 Sizing FactorDMA Area (ac)Orifice Flow ‐ %Q2Orifice AreaSoil Type Cover Slope (cfs/ac) (cfs) (in2)A2‐Pave OceansideDScrubFlat0.175 0.015 0.0000.01A2‐LS OceansideDScrubFlat0.175 0.103 0.0020.04A2‐Perm OceansideDScrubFlat0.175 0.014 0.0000.01ScrubA2B‐RoofOceansideDScrubFlat0.175 0.005 0.0000.00ScrubScrubScrubScrubScrubScrubScrubScrubScrubScrub0.002 0.06 0.27Tot. Allowable Orifice FlowTot. AllowableOrifice AreaMax Orifice Diameter(cfs)(in2)(in)0.002 0.050.25Actual Orifice Flow Actual Orifice AreaSelected Orifice Diameter(cfs)(in2)(in)Drawdown (Hrs) 25.8DMA NameOMWD Ops. & Admin.OMWD OceansideCarlsbadBMP Sizing Spreadsheet V2.0Carlsbad255‐040‐59BMP 1 Biofiltration w/ Partial Retention & Biofiltration w/o Impermeable Liner0.1Q2103,050Drawdown time exceeds 96 Hrs. Project must implement a vector control program.Pre‐developed Condition
Worksheet G.2‐1: Sizing Factor WorksheetSite InformationProject Name: Hydrologic Unit:Project Applicant: Rain Gauge:Jurisdiction: Total Project Area (sf):Assessor’s Parcel No.: Low Flow Threshold (*Q2):BMP Name: BMP Type:Areas Draining to BMP Sizing Factors Minimum BMP SizeArea (sf) Soil TypePre‐ProjectSlopeRunoff Factor (From Table G.2‐1)Surface AreaSurfaceVolumeSubsurfaceVolumeSurfaceArea(sf)SurfaceVolume(cf)SubsurfaceVolume(cf)A6‐Roof 2,672 D flat roof 1.00 0.1300 0.1083 0.0780347 289 208 A6‐Pave 1,227 D flat AC and concrete paving 1.00 0.1300 0.1083 0.0780160 133 96 A6‐LS 1,915 D flat landscape0.10 0.1300 0.1083 0.078025 21 15 A7‐Pave 9,937 D flat AC and concrete paving 1.00 0.1300 0.1083 0.07801,292 1,076 775 A7‐LS 189 D flat landscape0.10 0.1300 0.1083 0.07802 2 1 A10‐Roof 2,879 D flat roof 1.00 0.1300 0.1083 0.0780374 312 225 A10‐Pave 52 D flat concrete paving 1.00 0.1300 0.1083 0.07807 6 4 A10‐LS 1,449 D flat landscape0.10 0.1300 0.1083 0.078019 16 11 A10‐Perm 448 D flat permeable pavers 0.20 0.1300 0.1083 0.078012 10 7 A10A & 10B‐Roof 2,537 D flat roof 1.00 0.1300 0.1083 0.0780330 275 198 A11‐Pave 213 D flat concrete paving 1.00 0.1300 0.1083 0.078028 23 17 A11‐LS 6,080 D flat landscape0.10 0.1300 0.1083 0.078079 66 47 A5‐Roof 2,161 D flat roof 1.00 0.1300 0.1083 0.0780281 234 169 A5‐Pave 878 D flat concrete 1.00 0.1300 0.1083 0.0780114 95 68 A5‐LS 3,025 D flat landscape0.10 0.1300 0.1083 0.078039 33 24 ‐ ‐ ‐ Total DMA Area: 35,662 Min. BMP Size: 3,108 2,590 1,865 Proposed BMP Size: 3,110 2,363 2,081 Table G.2‐2: Unit Runoff Ratios Head on Low Flow Orifice (ft) Low Flow Orifice SizingUnit Runoff Ratio, Q2: 0.175cfs/ac Biofiltration w/Partial Retention, Biofiltration, Biofiltration w/Liner: 1.50 Low Flow Threshold (cfs): 0.0143Unit Runoff Ratio, Q10: 0.434cfs/ac Cistern, orifice head equal to 7/8 * cistern height: ‐ Max. Orifice Area (sq in): 0.3498Pre‐Dev. Q2: 0.143 cfsMax. Orifice Dia. (in): 0.667Pre‐Dev. Q10: 0.355 cfsMinimum 1/4" diameter, increment of 1/16": Proposed Orifice Dia. (in):0.6250BMP 4 Biofiltration w/Partial RetentionDMA Name Post Project Surface TypeCarlsbad 103,050255‐040‐59 0.1OMWD New & Remodeled Ops. & Admin.CarlsbadOMWD OceansidePage 1
Project Name: Hydrologic Unit:Project Applicant: Rain Gauge:Jurisdiction: Total Project Area:Parcel (APN): Low Flow Threshold:BMP Name BMP Type:Rain GaugeQ2 Sizing FactorDMA Area (ac)Orifice Flow ‐ %Q2Orifice AreaSoil Type Cover Slope (cfs/ac) (cfs) (in2)A6‐RoofOceansideDScrubFlat0.175 0.061 0.0010.03A6‐Pave OceansideDScrubFlat0.175 0.028 0.0000.01A6‐LS OceansideDScrubFlat0.175 0.044 0.0010.02A7‐Pave OceansideDScrubFlat0.175 0.228 0.0040.10A7‐LS OceansideDScrubFlat0.175 0.004 0.0000.00A10‐RoofOceansideDScrubFlat0.175 0.066 0.0010.03A10‐Pave OceansideDScrubFlat0.175 0.001 0.0000.00A10‐LS OceansideDScrubFlat0.175 0.033 0.0010.01A10‐Perm OceansideDScrubFlat0.175 0.010 0.0000.00A10A &10B‐RoofOceansideDScrubFlat0.175 0.058 0.0010.02A11‐Pave OceansideDScrubFlat0.175 0.005 0.0000.00A11‐LS OceansideDScrubFlat0.175 0.140 0.0020.06A5‐RoofOceansideDScrubFlat0.175 0.050 0.0010.02A5‐Pave OceansideDScrubFlat0.175 0.020 0.0000.01A5‐LS OceansideDScrubFlat0.175 0.069 0.0010.030.014 0.35 0.67Tot. Allowable Orifice FlowTot. AllowableOrifice AreaMax Orifice Diameter(cfs)(in2)(in)0.013 0.310.63Actual Orifice Flow Actual Orifice AreaSelected Orifice Diameter(cfs)(in2)(in)Drawdown (Hrs) 57.3Drawdown time exceeds 96 Hrs. Project must implement a vector control program.255‐040‐59 0.1Q2BMP 4 Biofiltration w/ Partial Retention & Biofiltration w/o Impermeable LinerDMA NamePre‐developed ConditionCarlsbad 103,050BMP Sizing Spreadsheet V2.0OMWD Ops. & Admin. CarlsbadOMWD Oceanside
Worksheet G.2‐1: Sizing Factor WorksheetSite InformationProject Name: Hydrologic Unit:Project Applicant: Rain Gauge:Jurisdiction: Total Project Area (sf):Assessor’s Parcel No.: Low Flow Threshold (*Q2):BMP Name: BMP Type:Areas Draining to BMP Sizing Factors Minimum BMP SizeArea (sf) Soil TypePre‐ProjectSlopeRunoff Factor (From Table G.2‐1)Surface AreaSurfaceVolumeSubsurfaceVolumeSurfaceArea(sf)SurfaceVolume(cf)SubsurfaceVolume(cf)B1B ‐ Roof 1,887 D flat roof 1.00 0.1300 0.1083 0.0780245 204 147 ‐ ‐ ‐ B2‐Roof 201 D flat roof 1.00 0.1300 0.1083 0.078026 22 16 B2‐Pave 1,604 D flat concrete 1.00 0.1300 0.1083 0.0780209 174 125 B2‐LS 4,359 D flat landscape 0.10 0.1300 0.1083 0.078057 47 34 B2‐Perm 380 D flat permeable pavers 0.20 0.1300 0.1083 0.078010 8 6 ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ Total DMA Area: 8,431 Min. BMP Size: 547 455 328 Proposed BMP Size: 604 412 374 Table G.2‐2: Unit Runoff Ratios Head on Low Flow Orifice (ft) Low Flow Orifice SizingUnit Runoff Ratio, Q2: 0.175cfs/ac Biofiltration w/Partial Retention, Biofiltration, Biofiltration w/Liner: 1.50 Low Flow Threshold (cfs): 0.0034Unit Runoff Ratio, Q10: 0.434cfs/ac Cistern, orifice head equal to 7/8 * cistern height: ‐ Max. Orifice Area (sq in): 0.0827Pre‐Dev. Q2: 0.034 cfsMax. Orifice Dia. (in): 0.325Pre‐Dev. Q10: 0.084 cfsMinimum 1/4" diameter, increment of 1/16": Proposed Orifice Dia. (in):0.3125DMA Name Post Project Surface TypeBMP 5 Biofiltration w/Partial RetentionCarlsbad 103,050255‐040‐59 0.1OMWD New & Remodeled Ops. & Admin.CarlsbadOMWD OceansidePage 1
Project Name: Hydrologic Unit:Project Applicant: Rain Gauge:Jurisdiction: Total Project Area:Parcel (APN): Low Flow Threshold:BMP Name BMP Type:Rain GaugeQ2 Sizing FactorDMA Area (ac)Orifice Flow ‐ %Q2Orifice AreaSoil Type Cover Slope (cfs/ac) (cfs) (in2)B1B ‐ RoofOceansideDScrubFlat0.175 0.043 0.0010.02ScrubB2‐RoofOceansideDScrubFlat0.175 0.005 0.0000.00B2‐Pave OceansideDScrubFlat0.175 0.037 0.0010.02B2‐LS OceansideDScrubFlat0.175 0.100 0.0020.04B2‐Perm OceansideDScrubFlat0.175 0.009 0.0000.00ScrubScrubScrubScrubScrubScrubScrubScrubScrub0.003 0.08 0.32Tot. Allowable Orifice FlowTot. AllowableOrifice AreaMax Orifice Diameter(cfs)(in2)(in)0.003 0.080.31Actual Orifice Flow Actual Orifice AreaSelected Orifice Diameter(cfs)(in2)(in)Drawdown (Hrs) 44.5Drawdown time exceeds 96 Hrs. Project must implement a vector control program.255‐040‐59 0.1Q2BMP 5 Biofiltration w/ Partial Retention & Biofiltration w/o Impermeable LinerDMA NamePre‐developed ConditionCarlsbad 103,050BMP Sizing Spreadsheet V2.0OMWD Ops. & Admin. CarlsbadOMWD Oceanside
Project Name: Hydrologic Unit:Project Applicant: Rain Gauge:Jurisdiction: Total Project Area:Parcel (APN): Low Flow Threshold:BMP Name: BMP Type:BMP Native Soil Type:BMP Infiltration Rate (in/hr):HMP Sizing Factors Minimum BMP SizeDMA NameArea (sf)Pre Project Soil TypePre‐Project SlopePost Project Surface TypeArea Weighted Runoff Factor(Table G.2‐1)1Surface Area Surface Area (SF)C4A‐Pave 631 D Flat Concrete 1.00.07 44C4A‐LS 4,527 D Flat Landscape 0.10.07 32C4B‐Pave 86 D Flat Concrete 1.00.07 6C4B‐LS 1,998 D Flat Landscape 0.10.07 14C4C‐Pave (off‐site) 15,508 D Flat Concrete 1.00.07 1086A4A‐Roof 1,987 D Flat Roofs 1.00.07 13900A2A‐Roof 2,694 D Flat Roofs 1.00.07 18900A4‐Pave 1,309 D Flat Concrete 1.00.07 92A4‐LS 3,074 D Flat Landscape 0.10.07 2200A4B‐Roof 1,070 D Flat Roofs 1.00.07 750000BMP Tributary Area 32,884Minimum BMP Size 1697Proposed BMP Size*176812.00 in18.00 in6.00 in12 in3.0 in3.5Underdrain OffsetBioretention Soil Media DepthFilter CourseGravel Storage Layer DepthSurface Ponding DepthAreas Draining to BMPCarlsbad255‐040‐59DBMP Sizing Spreadsheet V3.00.025Biofiltration w/ Partial Retention0.1Q2103,050OceansideCarlsbadBMP 6OMWD New & RemodeledOMWD
Project Name: Hydrologic Unit:Project Applicant: Rain Gauge:Jurisdiction: Total Project Area:Parcel (APN): Low Flow Threshold:BMP Name BMP Type:Rain Gauge Unit Runoff Ratio DMA Area (ac)Orifice Flow ‐ %Q2Orifice AreaSoil Type Slope (cfs/ac) (cfs) (in2)C4A‐Pave Oceanside D Flat 0.571 0.014 0.0010.01C4A‐LS Oceanside D Flat 0.571 0.104 0.0060.08C4B‐Pave Oceanside D Flat 0.571 0.002 0.0000.00C4B‐LS Oceanside D Flat 0.571 0.046 0.0030.04C4C‐Pave (off‐site) Oceanside D Flat 0.571 0.356 0.0200.29A4A‐Roof Oceanside D Flat 0.571 0.046 0.0030.04A2A‐Roof Oceanside D Flat 0.571 0.062 0.0040.05A4‐Pave Oceanside D Flat 0.571 0.030 0.0020.02A4‐LS Oceanside D Flat 0.571 0.071 0.0040.06A4B‐Roof Oceanside D Flat 0.571 0.025 0.0010.023.750.043 0.61 0.88Max Orifice HeadMax Tot. Allowable Orifice FlowMax Tot. AllowableOrifice AreaMax Orifice Diameter(feet)(cfs)(in2)(in)0.029 0.031 0.440.750Average outflow during surface drawdownMax Orifice Outflow Actual Orifice AreaSelected Orifice Diameter(cfs) (cfs)(in2)(in)Drawdown (Hrs) 17.0BMP 6Pre‐developed ConditionNo Orifice Required for Infiltration FacilitiesDMA NameCarlsbadBMP Sizing Spreadsheet V3.0Carlsbad255‐040‐59OMWD New & RemodeledOMWD0.1Q2103,050OceansideBiofiltration w/ Partial RetentionDrawdown time exceeds 96 Hrs. Project must implement a vector control program.
Worksheet G.2‐1: Sizing Factor WorksheetSite InformationProject Name: Hydrologic Unit:Project Applicant: Rain Gauge:Jurisdiction: Total Project Area (sf):Assessor’s Parcel No.: Low Flow Threshold (*Q2):BMP Name: BMP Type:Areas Draining to BMP Sizing Factors Minimum BMP SizeArea (sf) Soil TypePre‐ProjectSlopeRunoff Factor (From Table G.2‐1)Surface AreaSurfaceVolumeSubsurfaceVolumeSurfaceArea(sf)SurfaceVolume(cf)SubsurfaceVolume(cf)A4B‐Roof 1,070 Dflat roof1.00 0.0000 0.2000 0.0000‐ 214 ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ Total DMA Area: 1,070 Min. BMP Size: ‐ 214 ‐ Proposed BMP Size: ‐ 88 ‐ Table G.2‐2: Unit Runoff RatiosHead on Low Flow Orifice (ft)Low Flow Orifice SizingUnit Runoff Ratio, Q2: 0.175cfs/acBiofiltration w/Partial Retention, Biofiltration, Biofiltration w/Liner: ‐ Low Flow Threshold (cfs): 0.0004Unit Runoff Ratio, Q10: 0.434cfs/acCistern, orifice head equal to 7/8 * cistern height: 3.67 Max. Orifice Area (sq in): 0.0067Pre‐Dev. Q2: 0.004 cfsMax. Orifice Dia. (in): 0.092Pre‐Dev. Q10: 0.011 cfsMinimum 1/4" diameter, increment of 1/16": Proposed Orifice Dia. (in):0.2500DMA NamePost Project Surface TypeBMP 35CisternCarlsbad103,050255‐040‐590.1OMWD New & Remodeled Ops. & Admin.CarlsbadOMWD OceansidePage 1
Appendix G: Guidance for Continuous Simulation and Hydromodification Management Sizing
Factors
G.2.1 Unit Runoff Ratios
Table G.2-2 presents unit runoff ratios for calculating pre-development Q2, to be used when
applicable to determine the lower flow threshold for low flow orifice sizing for biofiltration with
partial retention, biofiltration, biofiltration with impermeable liner, or cistern BMPs. There is no low
flow orifice in the infiltration BMP or bioretention BMP. The unit runoff ratios are re-printed from
the BMP Sizing Calculator methodology. Unit runoff ratios for "urban" and "impervious" cover
categories were not transferred to this manual due to the requirement to control runoff to pre-
development condition (see Chapter 6.3.3).
How to use the unit runoff ratios:
Obtain unit runoff ratio from Table G.2-2 based on the project's rainfall basin, hydrologic soil
group, and pre-development slope (for redevelopment projects, pre-development slope may be
considered if historic topographic information is available, otherwise use pre-project slope). Multiply
the area tributary to the structural BMP (A, acres) by the unit runoff ratio (Q2, cfs/acre) to
determine the pre-development Q2 to determine the lower flow threshold, to use for low flow
orifice sizing.
Table G.2-2: Unit Runoff Ratios for Sizing Factor Method
Unit Runoff Ratios for Sizing Factor Method
Rain Gauge Soil Cover Slope Q2
(cfs/acre)
Q10
(cfs/ac)
Lake Wohlford A Scrub Low 0.136 0.369
Lake Wohlford A Scrub Moderate 0.207 0.416
Lake Wohlford A Scrub Steep 0.244 0.47
Lake Wohlford B Scrub Low 0.208 0.414
Lake Wohlford B Scrub Moderate 0.227 0.448
Lake Wohlford B Scrub Steep 0.253 0.482
Lake Wohlford C Scrub Low 0.245 0.458
Lake Wohlford C Scrub Moderate 0.253 0.481
Lake Wohlford C Scrub Steep 0.302 0.517
Lake Wohlford D Scrub Low 0.253 0.48
Lake Wohlford D Scrub Moderate 0.292 0.516
G-25 June 2015
Appendix G: Guidance for Continuous Simulation and Hydromodification Management Sizing
Factors
Unit Runoff Ratios for Sizing Factor Method
Rain Gauge Soil Cover Slope Q2
(cfs/acre)
Q10
(cfs/ac)
Lake Wohlford D Scrub Steep 0.351 0.538
Oceanside A Scrub Low 0.035 0.32
Oceanside A Scrub Moderate 0.093 0.367
Oceanside A Scrub Steep 0.163 0.42
Oceanside B Scrub Low 0.08 0.365
Oceanside B Scrub Moderate 0.134 0.4
Oceanside B Scrub Steep 0.181 0.433
Oceanside C Scrub Low 0.146 0.411
Oceanside C Scrub Moderate 0.185 0.433
Oceanside C Scrub Steep 0.217 0.458
Oceanside D Scrub Low 0.175 0.434
Oceanside D Scrub Moderate 0.212 0.455
Oceanside D Scrub Steep 0.244 0.571
Lindbergh A Scrub Low 0.003 0.081
Lindbergh A Scrub Moderate 0.018 0.137
Lindbergh A Scrub Steep 0.061 0.211
Lindbergh B Scrub Low 0.011 0.134
Lindbergh B Scrub Moderate 0.033 0.174
Lindbergh B Scrub Steep 0.077 0.23
Lindbergh C Scrub Low 0.028 0.19
Lindbergh C Scrub Moderate 0.075 0.232
Lindbergh C Scrub Steep 0.108 0.274
Lindbergh D Scrub Low 0.05 0.228
Lindbergh D Scrub Moderate 0.104 0.266
Lindbergh D Scrub Steep 0.143 0.319
G-26 June 2015
Appendix G: Guidance for Continuous Simulation and Hydromodification Management Sizing
Factors
Sizing Factors for Hydromodification Flow Control Biofiltration with Partial Retention and Biofiltration
BMPs Designed Using Sizing Factor Method
Lower Flow
Threshold Soil Group Slope Rain Gauge A V1 V2
0.1Q2 B Moderate Lindbergh N/A N/A N/A
0.1Q2 B Steep Lindbergh N/A N/A N/A
0.1Q2 C Flat Lindbergh 0.145 0.1208 0.0870
0.1Q2 C Moderate Lindbergh 0.145 0.1208 0.0870
0.1Q2 C Steep Lindbergh 0.120 0.1000 0.0720
0.1Q2 D Flat Lindbergh 0.160 0.1333 0.0960
0.1Q2 D Moderate Lindbergh 0.160 0.1333 0.0960
0.1Q2 D Steep Lindbergh 0.115 0.0958 0.0690
0.1Q2 A Flat Oceanside N/A N/A N/A
0.1Q2 A Moderate Oceanside N/A N/A N/A
0.1Q2 A Steep Oceanside N/A N/A N/A
0.1Q2 B Flat Oceanside N/A N/A N/A
0.1Q2 B Moderate Oceanside N/A N/A N/A
0.1Q2 B Steep Oceanside N/A N/A N/A
0.1Q2 C Flat Oceanside 0.130 0.1083 0.0780
0.1Q2 C Moderate Oceanside 0.130 0.1083 0.0780
0.1Q2 C Steep Oceanside 0.110 0.0917 0.0660
0.1Q2 D Flat Oceanside 0.130 0.1083 0.0780
0.1Q2 D Moderate Oceanside 0.130 0.1083 0.0780
0.1Q2 D Steep Oceanside 0.065 0.0542 0.0390
0.1Q2 A Flat L Wohlford N/A N/A N/A
0.1Q2 A Moderate L Wohlford N/A N/A N/A
0.1Q2 A Steep L Wohlford N/A N/A N/A
0.1Q2 B Flat L Wohlford N/A N/A N/A
0.1Q2 B Moderate L Wohlford N/A N/A N/A
0.1Q2 B Steep L Wohlford N/A N/A N/A
0.1Q2 C Flat L Wohlford 0.110 0.0917 0.0660
0.1Q2 C Moderate L Wohlford 0.110 0.0917 0.0660
0.1Q2 C Steep L Wohlford 0.090 0.0750 0.0540
0.1Q2 D Flat L Wohlford 0.100 0.0833 0.0600
0.1Q2 D Moderate L Wohlford 0.100 0.0833 0.0600
0.1Q2 D Steep L Wohlford 0.075 0.0625 0.0450
Q2 = 2-year pre-project flow rate based upon partial duration analysis of long-term hourly rainfall records
A = Surface area sizing factor for flow control
G-41 June 2015
Appendix G: Guidance for Continuous Simulation and Hydromodification Management Sizing
Factors
V1 = Surface volume sizing factor for flow control
V2 = Subsurface volume sizing factor for flow control
Definitions for "N/A"
• Soil groups A and B: N/A in all elements (A, V1, V2) for soil groups A and B means sizing factors were not developed for biofiltration (i.e., with an underdrain) for soil groups A and B. If no underdrain is proposed,
refer to Appendix G.2.3, Sizing Factors for Bioretention. If an underdrain is proposed, use project-specific continuous simulation modeling.
G-42 June 2015
Appendix G: Guidance for Continuous Simulation and Hydromodification Management Sizing
Factors
Sizing Factors for Hydromodification Flow Control Cistern Facilities Designed Using Sizing Factor Method
Lower Flow
Threshold Soil Group Slope Rain Gauge A V1 V2
0.3Q2 B Flat L Wohlford N/A 0.2600 N/A
0.3Q2 B Moderate L Wohlford N/A 0.2400 N/A
0.3Q2 B Steep L Wohlford N/A 0.1800 N/A
0.3Q2 C Flat L Wohlford N/A 0.1800 N/A
0.3Q2 C Moderate L Wohlford N/A 0.1800 N/A
0.3Q2 C Steep L Wohlford N/A 0.1400 N/A
0.3Q2 D Flat L Wohlford N/A 0.1400 N/A
0.3Q2 D Moderate L Wohlford N/A 0.1400 N/A
0.3Q2 D Steep L Wohlford N/A 0.1000 N/A
0.1Q2 A Flat Lindbergh N/A 0.1200 N/A
0.1Q2 A Moderate Lindbergh N/A 0.1000 N/A
0.1Q2 A Steep Lindbergh N/A 0.1000 N/A
0.1Q2 B Flat Lindbergh N/A 0.5400 N/A
0.1Q2 B Moderate Lindbergh N/A 0.7800 N/A
0.1Q2 B Steep Lindbergh N/A 0.3400 N/A
0.1Q2 C Flat Lindbergh N/A 0.3600 N/A
0.1Q2 C Moderate Lindbergh N/A 0.3600 N/A
0.1Q2 C Steep Lindbergh N/A 0.2400 N/A
0.1Q2 D Flat Lindbergh N/A 0.2600 N/A
0.1Q2 D Moderate Lindbergh N/A 0.2600 N/A
0.1Q2 D Steep Lindbergh N/A 0.1600 N/A
0.1Q2 A Flat Oceanside N/A 0.1600 N/A
0.1Q2 A Moderate Oceanside N/A 0.1400 N/A
0.1Q2 A Steep Oceanside N/A 0.1200 N/A
0.1Q2 B Flat Oceanside N/A 0.5100 N/A
0.1Q2 B Moderate Oceanside N/A 0.3400 N/A
0.1Q2 B Steep Oceanside N/A 0.2400 N/A
0.1Q2 C Flat Oceanside N/A 0.2600 N/A
0.1Q2 C Moderate Oceanside N/A 0.2600 N/A
0.1Q2 C Steep Oceanside N/A 0.2000 N/A
0.1Q2 D Flat Oceanside N/A 0.2000 N/A
0.1Q2 D Moderate Oceanside N/A 0.2000 N/A
0.1Q2 D Steep Oceanside N/A 0.1800 N/A
0.1Q2 A Flat L Wohlford N/A 0.1800 N/A
G-52 June 2015
Appendix G: Guidance for Continuous Simulation and Hydromodification Management Sizing
Factors
G-35 May 2018
G.2.1 Unit Runoff Ratios and Low Flow Control Orifice Design
G.2.1.1 Unit Runoff Ratios
Table G.2-2 presents unit runoff ratios for calculating pre-development Q2, to be used when
applicable to determine the lower flow threshold for low flow control orifice sizing for biofiltration
with partial retention, biofiltration, or cistern BMPs. There is no low flow control orifice in the
infiltration BMP. The unit runoff ratios are updated from the previously reported BMP Sizing
Calculator methodology ratios to account for changes in modeling methodologies. Unit runoff ratios
for "urban" and "impervious" cover categories were not transferred to this manual due to the
requirement to control runoff to pre-development condition (see Chapter 6.3.3).
How to use the unit runoff ratios:
Obtain unit runoff ratio from Table G.2-2 based on the project's rainfall basin, hydrologic soil
group, and pre-development slope (for redevelopment projects, pre-development slope may be
considered if historic topographic information is available, otherwise use pre-project slope). Multiply
the area tributary to the structural BMP (A, acres) by the unit runoff ratio (Q2, cfs/acre) to
determine the pre-development Q2 to determine the lower flow threshold, to use for low flow
control orifice sizing.
Table G.2-2: Unit Runoff Ratios for Sizing Factor Method
Rain Gauge Soil Pre-Project
Slope Q2 (cfs/acre) Q10 (cfs/acre)
Lake Wohlford A Flat 0.256 0.518
Lake Wohlford A Moderate 0.275 0.528
Lake Wohlford A Steep 0.283 0.531
Lake Wohlford B Flat 0.371 0.624
Lake Wohlford B Moderate 0.389 0.631
Lake Wohlford B Steep 0.393 0.633
Lake Wohlford C Flat 0.490 0.729
Lake Wohlford C Moderate 0.495 0.733
Lake Wohlford C Steep 0.496 0.735
Lake Wohlford D Flat 0.548 0.784
Lake Wohlford D Moderate 0.554 0.788
Appendix G: Guidance for Continuous Simulation and Hydromodification Management Sizing
Factors
G-36 May 2018
Rain Gauge Soil Pre-Project
Slope Q2 (cfs/acre) Q10 (cfs/acre)
Lake Wohlford D Steep 0.556 0.788
Oceanside A Flat 0.256 0.679
Oceanside A Moderate 0.277 0.694
Oceanside A Steep 0.285 0.700
Oceanside B Flat 0.377 0.875
Oceanside B Moderate 0.391 0.879
Oceanside B Steep 0.395 0.881
Oceanside C Flat 0.488 0.981
Oceanside C Moderate 0.497 0.985
Oceanside C Steep 0.499 0.986
Oceanside D Flat 0.571 0.998
Oceanside D Moderate 0.575 0.999
Oceanside D Steep 0.576 0.999
Lindbergh A Flat 0.057 0.384
Lindbergh A Moderate 0.073 0.399
Lindbergh A Steep 0.082 0.403
Lindbergh B Flat 0.199 0.496
Lindbergh B Moderate 0.220 0.509
Lindbergh B Steep 0.230 0.513
Lindbergh C Flat 0.335 0.601
Lindbergh C Moderate 0.349 0.610
Lindbergh C Steep 0.354 0.613
Lindbergh D Flat 0.429 0.751
Lindbergh D Moderate 0.437 0.753
Lindbergh D Steep 0.439 0.753
Appendix G: Guidance for Continuous Simulation and Hydromodification Management Sizing
Factors
G-41 May 2018
G.2.3 Sizing Factors for Biofiltration with Partial Retention
Table G.2-4 presents sizing factors for calculating the required surface area (A) for a biofiltration
with partial retention BMP. The BMPs consist of four layers:
•Ponding layer: 12-inches active storage, [minimum] 2-inches of freeboard above overflow
relief
•Media Layer: 18-inches of soil [bioretention soil media]
•Filter Course: 6-inches
•Storage layer: 18-inches of gravel at 40 percent porosity for A and B soils and 12-inches of
gravel at 40 percent porosity for C and D soils. The underdrain offset for A and B soils shallbe 18-inches, for C soils it shall be 6-inches and for D soils it shall be 3-inches.
•Overflow structure: San Diego Regional Standard Drawing Type I Catch Basin (D-29). For
the purposes of hydromodification flow control other type of overflow structures are
allowed.
This BMP does not include an impermeable layer at the bottom of the facility to prevent infiltration
into underlying soils, regardless of hydrologic soil group. If a facility is to be lined, the designer must
use the sizing factors for biofiltration (Refer to Appendix G.2.4).
Biofiltration with Partial Retention BMP Example Illustration
How to use the sizing factors for flow control BMP Sizing:
Obtain sizing factors from Table G.2-4 based on the project's lower flow threshold fraction of Q2,
hydrologic soil group, pre-project slope, and rain gauge (rainfall basin). Multiply the area tributary to
Appendix G: Guidance for Continuous Simulation and Hydromodification Management Sizing
Factors
G-42 May 2018
the structural BMP (A, square feet) by the area weighted runoff factor (C, unitless) (see Table G.2-1)
by the sizing factors to determine the required surface area (A, square feet). Select a low flow control
orifice for the underdrain that will discharge the lower flow threshold flow at the overflow riser
elevation. Standard head (H) for this calculation (based on the standard detail) is 3.0 feet for A or B
soils, 3.5 feet for C soils, or 3.75 feet for D soils. The civil engineer shall provide the necessary
surface area of the BMP and the underdrain and orifice detail on the plans.
Additional steps to use this BMP as a combined pollutant control and flow control BMP:
The BMP sized using the sizing factors in Table G.2-4 meets both pollutant control and flow
control requirements.
Table G.2-4: Sizing Factors for Hydromodification Flow Control Biofiltration with Partial Retention
BMPs Designed Using Sizing Factor Method
Lower Flow
Threshold Soil Group Pre-
Project
Slope
Aggregate below low
orifice invert
(inches)
Rain Gauge A
0.1Q2 A Flat 18 Lindbergh 0.080
0.1Q2 A Moderate 18 Lindbergh 0.080
0.1Q2 A Steep 18 Lindbergh 0.080
0.1Q2 B Flat 18 Lindbergh 0.065
0.1Q2 B Moderate 18 Lindbergh 0.065
0.1Q2 B Steep 18 Lindbergh 0.060
0.1Q2 C Flat 6 Lindbergh 0.050
0.1Q2 C Moderate 6 Lindbergh 0.050
0.1Q2 C Steep 6 Lindbergh 0.050
0.1Q2 D Flat 3 Lindbergh 0.050
0.1Q2 D Moderate 3 Lindbergh 0.050
0.1Q2 D Steep 3 Lindbergh 0.050
0.1Q2 A Flat 18 Oceanside 0.080
0.1Q2 A Moderate 18 Oceanside 0.075
0.1Q2 A Steep 18 Oceanside 0.075
0.1Q2 B Flat 18 Oceanside 0.070
Appendix G: Guidance for Continuous Simulation and Hydromodification Management Sizing
Factors
G-43 May 2018
Lower Flow
Threshold Soil Group Pre-
Project
Slope
Aggregate below low
orifice invert
(inches)
Rain Gauge A
0.1Q2 B Moderate 18 Oceanside 0.070
0.1Q2 B Steep 18 Oceanside 0.070
0.1Q2 C Flat 6 Oceanside 0.070
0.1Q2 C Moderate 6 Oceanside 0.070
0.1Q2 C Steep 6 Oceanside 0.070
0.1Q2 D Flat 3 Oceanside 0.070
0.1Q2 D Moderate 3 Oceanside 0.070
0.1Q2 D Steep 3 Oceanside 0.070
0.1Q2 A Flat 18 L Wohlford 0.110
0.1Q2 A Moderate 18 L Wohlford 0.110
0.1Q2 A Steep 18 L Wohlford 0.105
0.1Q2 B Flat 18 L Wohlford 0.090
0.1Q2 B Moderate 18 L Wohlford 0.085
0.1Q2 B Steep 18 L Wohlford 0.085
0.1Q2 C Flat 6 L Wohlford 0.065
0.1Q2 C Moderate 6 L Wohlford 0.065
0.1Q2 C Steep 6 L Wohlford 0.065
0.1Q2 D Flat 3 L Wohlford 0.060
0.1Q2 D Moderate 3 L Wohlford 0.060
0.1Q2 D Steep 3 L Wohlford 0.060
Q2 = 2-year pre-project flow rate based upon partial duration analysis of long-term hourly rainfall records
A = Surface area (at surface of the BMP before any ponding occurs) sizing factor for flow control
Appendix G: Guidance for Continuous Simulation and Hydromodification Management Sizing
Factors
G-47 May 2018
G.2.5 Sizing Factors for "Cistern" BMP
Table G.2-6 presents sizing factors for calculating the required volume (V) for a cistern BMP. In this
context, a "cistern" is a detention facility that stores runoff and releases it at a controlled rate. A
cistern can be a component of a harvest and use system, however the sizing factor method will not
account for any retention occurring in the system. The sizing factors were developed assuming
runoff is released from the cistern. The sizing factors presented in this section are to meet the
hydromodification management performance standard only. The cistern BMP is based on the
following assumptions:
•Cistern configuration: The cistern is modeled as a 4-foot tall vessel. However, designerscould use other configurations (different cistern heights), as long as the lower outlet orifice is
sized to properly restrict outflows and the minimum required volume is provided.
•Cistern upper outlet: The upper outlet from the cistern would consist of a weir or other
flow control structure with the overflow invert set at an elevation of 7/8 of the water height
associated with the required volume of the cistern – V. For the assumed 4-foot water depth
in the cistern associated with the sizing factor analysis, the overflow invert is assumed to be
located at an elevation of 3.5 feet above the bottom of the cistern. The overflow weir would
be sized to pass the peak design flow based on the tributary drainage area.
How to use the sizing factors:
Obtain sizing factors from Table G.2-6 based on the project's lower flow threshold fraction of Q2,
hydrologic soil group, pre-project slope, and rain gauge (rainfall basin). Multiply the area tributary to
the structural BMP (A, square feet) by the area weighted runoff factor (C, unitless) (see Table G.2-1)
by the sizing factors to determine the required volume (V, cubic feet). Select a low flow control
orifice that will discharge the lower flow threshold flow at the overflow elevation (i.e. when there is
3.5 feet of head over the lower outlet orifice or adjusted head as appropriate if the cistern overflow
elevation is not 3.5 feet tall). The civil engineer shall provide the necessary volume of the BMP and
the lower outlet orifice detail on the plans.
Additional steps to use this BMP as a combined pollutant control and flow control BMP:
A cistern could be a component of a full retention, partial retention, or no retention BMP depending
on how the outflow is disposed. However, use of the sizing factor method for design of the cistern
in a combined pollutant control and flow control system is not recommended. The sizing factor
method for designing a cistern does not account for any retention or storage occurring in BMPs
combined with the cistern (i.e., cistern sized using sizing factors may be larger than necessary
because sizing factor method does not recognize volume losses occurring in other elements of a
combined system). Furthermore, when the cistern is designed using the sizing factor method, the
cistern outflow must be set to the low flow threshold flow for the drainage area, which may be
inconsistent with requirements for other elements of a combined system. To optimize a system in
Appendix G: Guidance for Continuous Simulation and Hydromodification Management Sizing
Factors
G-48 May 2018
which a cistern provides temporary storage for runoff to be either used onsite (harvest and use),
infiltrated, or biofiltered, project-specific continuous simulation modeling is recommended. Refer to
Sections 5.6 and 6.3.6.
Table G.2-6: Sizing Factors for Hydromodification Flow Control Cistern BMPs Designed Using
Sizing Factor Method
Lower Flow
Threshold Soil Group Pre-Project Slope Rain Gauge V
0.1Q2 A Flat Lindbergh 0.54
0.1Q2 A Moderate Lindbergh 0.51
0.1Q2 A Steep Lindbergh 0.49
0.1Q2 B Flat Lindbergh 0.19
0.1Q2 B Moderate Lindbergh 0.18
0.1Q2 B Steep Lindbergh 0.18
0.1Q2 C Flat Lindbergh 0.11
0.1Q2 C Moderate Lindbergh 0.11
0.1Q2 C Steep Lindbergh 0.11
0.1Q2 D Flat Lindbergh 0.09
0.1Q2 D Moderate Lindbergh 0.09
0.1Q2 D Steep Lindbergh 0.09
0.1Q2 A Flat Oceanside 0.26
0.1Q2 A Moderate Oceanside 0.25
0.1Q2 A Steep Oceanside 0.25
0.1Q2 B Flat Oceanside 0.16
0.1Q2 B Moderate Oceanside 0.16
0.1Q2 B Steep Oceanside 0.16
0.1Q2 C Flat Oceanside 0.14
0.1Q2 C Moderate Oceanside 0.14
0.1Q2 C Steep Oceanside 0.14
0.1Q2 D Flat Oceanside 0.12
A3-1
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:
SEE OPERATION AND MAINTENANCE PLAN
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. (NOT APPLICABLE)
A3-2
Typical Maintenance Indicators and Actions for Proposed Structural BMP(s)
Vegetated Infiltration or Filtration BMPs
BMP: 1, 4, 5, 6 (Biofiltration w/Partial Retention)
Typical Maintenance Indicators 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 [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.
A3-3
Typical Maintenance Indicators Maintenance Actions
☒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.
A3-4
Typical Maintenance Indicators and Actions for Proposed Structural BMP(s)
Non-Vegetated Infiltration BMPs
BMP: 22, 23, 25, 26, 27, 28, 29, 30, 80, 81 (Permeable Pavement)
Typical Maintenance Indicators Maintenance Actions
☒Accumulation of sediment, litter, or debris
in infiltration basin, pre-treatment 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.
☒Damage to permeable paving surface Repair or replace damaged surface as
appropriate.
* 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.
A3-5
Typical Maintenance Indicators and Actions for Proposed Structural BMP(s)
Non-Vegetated Filtration BMPs
BMP: 59 – 64 (Inlet Filters)
Typical Maintenance Indicators 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.
A3-6
Typical Maintenance Indicators and Actions for Proposed Structural BMP(s)
Detention BMPs
BMP: 35 (Cisterns)
Typical Maintenance Indicators Maintenance Actions
☒Erosion due to concentrated storm water
runoff flow
Repair eroded areas and energy dissipation
devices at discharge outlets.
☒Accumulation of sediment, litter, or debris Remove and properly dispose of materials that
accumulate inside the cistern.
☒Standing water Remove soil or debris from outlets.
☒Obstructed inlet Clear obstructions from inlet pipes or inlet
filters/screens.
☒Damage to structural components such as
pipes, inlet screens or outlets
Repair or replace as applicable.
A4-1
ATTACHMENT 4 – CITY STANDARD SINGLE SHEET BMP (SSBMP) EXHIBIT
RANCHO SANTA FE ROADOM
W
D
D
R
I
V
E
W
A
Y
OLIVENHAIN ROAD
TO SO
U
T
H
SI
D
E
OPER
A
TI
O
N
S
B
UI
L
DI
N
G SOIL TYPE "D"SOIL TYPE "C"1. THESE BMPS ARE MANDATORY TO BE INSTALLED PER MANUFACTURER'S
RECOMMENDATIONS OR THESE PLANS.
2. NO CHANGES TO THE PROPOSED BMPS ON THIS SHEET WITHOUT PRIOR
APPROVAL FROM THE CITY ENGINEER.
3. NO SUBSTITUTIONS TO THE MATERIAL OR TYPES OR PLANTING TYPES
WITHOUT PRIOR APPROVAL FROM THE CITY ENGINEER.
4. NO OCCUPANCY WILL BE GRANTED UNTIL THE CITY INSPECTION STAFF
HAS INSPECTED THIS PROJECT FOR APPROPRIATE BMP CONSTRUCTION
AND INSTALLATION.
BMP NOTES:
PARTY RESPONSIBLE FOR MAINTENANCE:
NAME: OLIVENHAIN MUNICIPAL WATER DISTRICT
PHONE NO. (760) 753-6466
CONTACT
PLAN PREPARED BY:
NAME: ROBERT WEBER
PHONE NO. (858) 413-2400
CERTIFICATION
COMPANY: INFRASTRUCTURE ENGINEERING CORP.
SCALE : 1" =20'-0"
5. REFER TO MAINTENANCE AGREEMENT DOCUMENT.
6. SEE PROJECT SWMP FOR ADDITIONAL INFORMATION.
SIGNATURE
ADDRESS: 1966 OLIVENHAIN ROAD
ENCINITAS, CA 92024
ADDRESS: 14271 DANIELSON STREET
POWAY, CA. 92064
LEGEND
CHAD WILLIAMS
E N G I N E E R I N G C O R P O R A T I O N
32
C-32
BL
DP
RW
33
7
1
TREATMENT CONTROL
LOW IMPACT DESIGN (L.I.D.)
SOURCE CONTROL
20
HYDROMODIFICATION & TREATMENT CONTROL
HYDROMODIFICATION
82
X
X
59 74
**
PERVIOUS CONC.
PAVEMENT
PERVIOUS
INTERLOCKING
PAVERS
25 30
22 23
31
SITE DESIGN
34
59 64
*PRIOR TO THE RAINY SEASON (OCT 1 THROUGH APR 30)
80 81 POROUS PAVING -
GRASS
SD-6B
TC-10 2,350 SF.502-9A
502-9A
502-9A
502-9A
502-9A
502-9A
502-9A
502-9A
502-9A
13-15 SEMI-ANNUALLY SEMI-ANNUALLY
SEMI-ANNUALLY SEMI-ANNUALLY
SEMI-ANNUALLYQUARTERLY
SD-6B
TC-10
SD-6B
TC-10
1,706 SF.
1,001 SF.
BMP ID #BMP TYPE SYMBOL
SDBMP,
CARLSBAD OR
CASQA NO.
QUANTITY DRAWING NO.SHEET NO.(S)INSPECTION
FREQUENCY
MAINTENANCE
FREQUENCY
14, 15
13
BMP TABLE
BIOFILTRATION PR-1 271 SF.QUARTERLY SEMI-ANNUALLY14
WET VAULT
(INCLUDES CISTERN)MP-50
ROOF DRAIN TO
LANDSCAPING
INLET FILTER
VEGETATIVE
SWALE
FT-1
TC-30
MP-52
SD-11 14 EA.
7 EA.
0 SF.
ANNUALLY ANNUALLY
ANNUALLYSEMI-ANNUALLY
13-15
13-15
PER
LANDSCAPE
13
13-15
STREET TREES SD-1 4 EA.ANNUALLY ANNUALLY
SEMI-ANNUALLY
ANNUALLY
ANNUALLY
ANNUALLY
1 EA.
16 EA.
GS-16
SD-13NO DUMPING
DRAINS TO OCEANSTENCILS
TRASH
ENCLOSURE
502-9ABIOFILTRATION3,282 SF.QUARTERLY SEMI-ANNUALLY15
502-9ABIOFILTRATION676 SF.QUARTERLY SEMI-ANNUALLY13
502-9ABIOFILTRATION1,885 SF.QUARTERLY SEMI-ANNUALLY16
4
5
6
502-9A 14CISTERNHU-1 1 EA. / 660 GAL.ANNUALLYSEMI-ANNUALLY35
PR-1
PR-1
PR-1
A5-1
ATTACHMENT 5 – OPERATION AND MAINTENANCE PLAN