HomeMy WebLinkAboutAMEND 2023-0001; SMAC; LIMITED GEOTECHNICAL INVESTIGATION; 2024-02-29
Civil Engineering • Land Planning • Surveying
STORM WATER QUALITY MANAGEMENT PLAN
(SWQMP)
SMAC Shell Building
PUD 2017-0008 (DEV 2017-0169)
August 10, 2018
Revised April 18, 2025
Van Allen Way
Carlsbad, CA 92008
APN 212-120-01
Prepared For:
5801-5807 Van Allen Owner, LLC
12501 Seal Beach Boulevard, Suite 225
Seal Beach, CA 90740
KARN Engineering and Surveying, Inc.
Scott Harry, P.E., P.L.S
760-728-1134
www.karnengineeering.com
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CITY OF CARLSBAD
PRIORITY DEVELOPMENT PROJECT (PDP)
STORM WATER QUALITY MANAGEMENT PLAN
(SWQMP) FOR
SMAC Shell Building
PUD 2017-0008 {DEV 2017-0169)
ENGINEER OF WORK:
~792
PREPARED FOR:
SMAC
5807 Van Allen Way
Carlsbad, CA 92008
760-929-7575
PREPARED BY:
KARN Engineering and Surveying, !Inc .
129 W. Fig Street
Fallbrook, CA 92028
760-728-1134
DATE:
August 10, 2018
Addendum 1: 4/18/25 Revision for increased parking spaces
Attachment 1f: Trash Capture Calculations and Specifications
Attachment 2e: Hydromodification Calculations
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TABLE OF CONTENTS
Certification Page
Project Vicinity Map
FORM E-34 Storm Water Standard Questionnaire
Site Information
FORM E-36 Standard Project Requirement Checklist
Summary of PDP Structural BMPs
Attachment 1: Backup for PDP Pollutant Control BMPs
Attachment 1 a: OMA Exhibit
Attachment 1 b: Tabular Summary of DMAs and Design Capture Volume Calculations
Attachment 1 c: Harvest and Use Feasibility Screening (when applicable)
Attachment 1 d: Categorization of Infiltration Feasibility Condition (when applicable)
Attachment 1 e: 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
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CERTIFICATION PAGE
Project Name: SMAC
Project ID: PUD 2017-0008 (DEV 2017-0169)
I hereby declare that I am the Engineer in Responsible Charge of design of storm water BMPs
for this project, and that I have exercised responsible charge over the design of the project as
defined in Section 6703 of the Business and Professions Code, and that the design is consistent
with the requirements of the BMP Design Manual, which is based on the requirements of
SDRWQCB Order No. R9-2013-0001 (MS4 Permit) or the current Order .
I have read and understand that the City Engineer has adopted minimum requirements for
managing urban runoff, including storm water, from land development activities, as described in
the BMP Design Manual. I certify that this SWQMP has been completed to the best of my ability
and accurately reflects the project being proposed and the applicable source control and site
design BMPs proposed to minimize the potentially negative impacts of this project's land
development activities on water quality. I understand and acknowledge that the plan check
review of this SWQMP by the City Engineer is confined to a review and does not relieve me, as
the Engineer in Responsible Charge of design of storm water BMPs for this project, of my
responsibilities for project design .
R.C.E. 63792 Exp. 9-30-20
KARN Engineering and Surveying, Inc .
Date 1
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PROJECT VICINITY MAP
CITY OF OCEANSIDE
PACIFIC
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CITY OF
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OLLEGE
LVD .
NOT TO
SCALE
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C_cicyof
Carlsbad
STORM WATER STANDARDS
QUESTIONNAIRE
Development Services
Land Development Engineering
1635 Faraday Avenue
(760) 602-2750
www.carlsbadca.gov
E-34
I 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 (BMPs) into the project design per Carlsbad BMP Design Manual (BMP Manual). To view the BMP Manual,
refer to the Engineering Standards (Volume 5) .
This questionnaire must be completed by the applicant in advance of submitting for a development application
(subdivision, discretionary permits and/or construction permits). The results of the questionnaire determine the level of
storm water standards that must be applied to a proposed development or redevelopment project. Depending on the
outcome, your project will either be subject to 'STANDARD PROJECT' requirements 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: SMAC Shell Building PROJECT ID: PUD 2017-0008
ADDRESS: Van Allen Way, Carlsbad, CA 92008 APN : 212-120-01
The project is (check one): IX] New Development D Redevelopment
The total proposed disturbed area is: ft2 ( 3.20 ) acres
The total proposed newly created and/or replaced impervious area is: 941249 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 1 of 4 REV 02/16
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STEP1
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 .
STEP2
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; □ lXl 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 quidance?
2. Retrofitting or redeveloping existing paved alleys, streets, or roads that are designed and constructed in □ IX] 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? □ Kl
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 2 of 4 REV 04/17
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STEP3
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, IX] □
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 □ IX] 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 □ IX]
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 □ IX]
development project includes development on any natural slope that is twenty-five percent or Qreater .
5. Is your project a new or redevelopment project that creates and/or replaces 5,000 square feet or more
of impervious surface collectively over the entire project site and supports a parking lot? A parking lot is ~ □ a land area or facility for the temporary parking or storage of motor vehicles used personally for
business or for commerce.
6 . Is your project a new or redevelopment project that creates and/or replaces 5,000 square feet or more
of impervious street, road, highway, freeway or driveway surface collectively over the entire project IX] □ site? A street, road, highway, freeway or driveway is any paved impervious surface used for the
transportation of automobiles, trucks, motorcvcles, 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 □ [XI
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 □ [XI 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 □ fXI 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 IX] □ 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 □ IX]
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 statinQ "My project is a 'STANDARD PROJECT' ... " and complete applicant information .
E-34 Page 3 of 4 REV 04/17
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STEP4
TO BE COMPLETED FOR REDEVELOPMENT PROJECTS THAT ARE PRIORITY DEVELOPMENT PROJECTS (PDP)
ONLY
Complete the questions below regarding your redevelopment project (MS4 Permit Provision E.3.b.(2)):
YES NO
Does the redevelopment project result in the creation or replacement of impervious surface in an amount
of less than 50% of the surface area of the previously existing development? Complete the percent
impervious calculation below:
Existing impervious area (A)= sq . ft. □ □
Total proposed newly created or replaced impervious area (B) = sq. ft.
Percent impervious area created or replaced (B/A)*100 = %
If you answered "yes", the structural BMPs required for PDP apply only to the creation or replacement of impervious
surface and not the entire development. Go to step 5, 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.
STEPS
CHECK THE APPROPRIATE BOX AND COMPLETE APPLICANT INFORMATION
.lXI 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 .
D My Project is NOT a 'development project' and is not subject to the requirements of the BMP Manual.
Applicant Information and Signature Box
Applicant Name: SMAC Corporation Applicant Title: Ed Neff, CEO
Applicant Signature: Date:
.. • Environmentally Sensitive Areas include but are not limited to all Clean Water Act Section 303(d) 1mpa1red 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 Citv Use Onlv
YES NO
City Concurrence: □ □
By:
Date:
Project ID:
E-34 Page 4 of 4 REV 04/17
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SITE INFORMATION CHECKLIST
Project Summary Information
Project Name SMAC Shell Building
Project ID PUD 2017-0008 (DEV 201 7-0169)
Project Address Van Allen Way
Carlsbad, CA 92008
Assessor's Parcel Number(s) (APN(s)) 212-120-01
Project Watershed (Hydrologic Unit) Carlsbad 904 (Agua Hedionda HA 904.3)
Parcel Area 3.07 Acres (133,729 Square Feet)
Existing Impervious Area
0 Acres (0 Square Feet) (subset of Parcel Area)
Area to be disturbed by the project
3.20 Acres (152,460 Square Feet) (Project Area)
Project Proposed Impervious Area
2.16 Acres (94,249 Square Feet) (subset of Project Area)
Project Proposed Pervious Area
1.04 Acres (43,502 Square Feet) ( subset of Project Area)
Note: Proposed Impervious Area + Proposed Pervious Area = Area to be Disturbed by the
Project.
This may be less than the Parcel Area .
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DescriDtion of Existing Site Condition and Drainage Patterns
Current Status of the Site (select all that apply):
o Existing development
~ Previously graded but not built out
D Agricultural or other non-impervious use
D Vacant, undeveloped/natural
Description/ Additional Information:
Existing Land Cover Includes (select all that apply):
~ Vegetative Cover
D Non-Vegetated Pervious Areas
o Impervious Areas
Description/ Additional Information:
Underlying Soil belongs to Hydrologic Soil Group (select all that apply):
ONRCS Type A
D NRCS Type B
D NRCS Type C
~NRCS Type D
Approximate Depth to Groundwater (GW):
D GW Depth < 5 feet
o 5 feet < GW Depth < 1 0 feet
o 1 0 feet < GW Depth < 20 feet
® GW Depth > 20 feet
Existing Natural Hydrologic Features (select all that apply):
o Watercourses
□ Seeps
D Springs
□Wetlands
IX None
Description / Additional Information:
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Description of Existing Site Topography and Drainage [How is storm water runoff conveyed from
the site? At a minimum, this description should answer (1) whether existing drainage
conveyance is natural or urban; (2) describe existing constructed storm water conveyance
systems, if applicable; and (3) is runoff from offsite conveyed through the site? if so, describe]:
The existing property is a 3.07 acre mass graded site that slopes in a northwesterly
direction. Runoff from the site sheet flows to an existing storm drain that conveys
the site runoff to the storm drain system within Faraday Avenue. No runoff from
adjacent parcels is conveyed through the site .
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Description of Proposed Site Development and Drainage Patterns
Project Description / Proposed Land Use and/or Activities:
The project is proposing a shell type industrial building with associated parking .
List/describe proposed impervious features of the project (e.g ., buildings, roadways, parking
lots, courtyards, athletic courts, other impervious features):
The project proposes a 55,000 square foot industrial building with associated parking and
drive aisles. Are courtyard type area is proposed along the east portion of the building .
List/describe proposed pervious features of the project (e.g., landscape areas):
The project proposes landscaping throughout the parking area and along the
perimeter adjacent to Faraday Avenue and Van Allen Way.
Does the project include grading and changes to site topography?
!!Yes
□No
Description/ Additional Information:
The project proposes site grading that will maintain the existing runoff
pattern, i.e. sheet flow towards the northwest comer of the property .
Does the project include changes to site drainage (e.g., installation of new storm water
conveyance systems)?
~Yes
□No
Description/ Additional Information:
An 18" storm drain will convey runoff from the proposed low point near the southwest
comer of the property to the proposed biofiltration basin. Runoff from the loading dock
area will be conveyed within a storm drain that will connect to the biofiltration basin.
A modular wetland system will be installed near the northwest comer of the site that
will connect to the existing 24" RCP draining to Faraday Avenue .
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Identify whether any of the following features, activities, and/or pollutant source areas will be
present (select all that apply):
IX On-site storm drain inlets
D Interior floor drains and elevator shaft sump pumps
D Interior parking garages
D Need for future indoor & structural pest control
Kl Landscape/Outdoor Pesticide Use
D Pools, spas, ponds, decorative fountains, and other water features
o Food service
rg Refuse areas
IX Industrial processes
~ Outdoor storage of equipment or materials
D Vehicle and Equipment Cleaning
D Vehicle/Equipment Repair and Maintenance
o Fuel Dispensing Areas
(g Loading Docks
~ Fire Sprinkler Test Water
E Miscellaneous Drain or Wash Water
Ii Plazas, sidewalks, and parking lots
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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 flows from the site to Agua Hedionda Creek, to Agua Hedionda Lagoon, to
the Pacific Ocean .
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
Agua Hedionda Creek Bacterial indicator, manganese,
phosphorus, selenium, TDS, total
nitrogen, and toxicity,
enterococcus, tecaJ co11torm .
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 8.6):
Also a Receiving
Not Applicable to Anticipated from the Water Pollutant of
Pollutant the Project Site Project Site Concern
Sediment X
Nutrients X X
Heavy Metals X X
OrQanic Compounds X X
Trash & Debris X
Oxygen Demanding X Substances
Oil & Grease X
Bacteria & Viruses X X
Pesticides X X
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Hydromodification Manaaement Requirements
Do hydromodification management requirements apply (see Section 1.6 of the BMP Design
Manual)?
00 Yes, hydromodification management flow control structural BMPs required .
D 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.
D No, the project will discharge runoff directly to an area identified as appropriate for an
exemption by the WMAA for the watershed in which the project resides .
Description / Additional Information (to be provided if a 'No' answer has been selected above):
Critical Coarse Sediment Yield Areas*
*This Section only required if hydromodification management requirements aDDIY
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
D 6.2.2 Downstream Systems Sensitivity to Coarse Sediment
D 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?
D 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 .
D 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:
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Flow Control for Post-Project Runofr
"This Section only required if hydromodificatlon management reauirements 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.
The biofiltration basin has been to designed to meet the hydromodification flow
requirements. POC-1 is located within the biofiltration basin near the northwest comer
of the site. A 9'x9' tree well is located near the north driveway connection with
Faraday A venue for water quality treament purposes. The hydromodification and 100
year detention within the biofiltration basin are sufficient to offset the tree well flows .
Has a geomorphic assessment been performed for the receiving channel(s)?
~ No, the low flow threshold is 0.102 (default low flow threshold)
D Yes, the result is the low flow threshold is 0.102
D Yes, the result is the low flow threshold is 0.302
D Yes, the result is the low flow threshold is 0.502
If a geomorphic assessment has been performed, provide title, date, and preparer:
Discussion/ Additional Information: (optional)
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Other Site Reauirements 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 .
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 .
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Ccicyof
Carlsbad
Project Name: SMAC Shell Building
Project ID: PUD 2011-ooos (DEV 2011-0169)
DWG No. or Building Permit No.:
STANDARD PROJECT
REQUIREMENT
CHECKLIST
E-36
Project Information
Source Control BMPs
Development Services
Land Development Engineering
1635 Faraday Avenue
(760) 602-2750
www.carlsbadca.gov
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 (Volume 5 of City Engineering Standards) 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. Please add attachments if more space is needed .
• "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 Iii Yes 0 No 0 N/A
Discussion/justification if SC-1 not implemented:
SC-2 Storm Drain Stenciling or Signage Iii Yes D No 0 N/A
Discussion/justification if SC-2 not implemented:
SC-3 Protect Outdoor Materials Storage Areas from Rainfall, Run-On, Runoff, and Wind □Yes 0 No Iii N/A Dispersal
Discussion/justification if SC-3 not implemented:
No outdoor material storage areas are proposed for this site .
E-36 Page 1 of 4 Revised 09/16
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Source Control Requirement (continued) Applied?
SC-4 Protect Materials Stored in Outdoor Work Areas from Rainfall, Run-On, Runoff, and □ Yes □ No Iii N/A Wind Dispersal
Discussion/justification if SC-4 not implemented:
No outdoor work areas are proposed .
SC-5 Protect Trash Storage Areas from Rainfall, Run-On, Runoff, and Wind Dispersal Iii Yes □ No □ N/A
Discussion/justification if SC-5 not implemented:
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 Iii Yes □ No □ N/A
□ Interior floor drains and elevator shaft sump pumps □ Yes □ No Iii N/A
□ Interior parking garages □ Yes □ No Iii N/A
□ Need for future indoor & structural pest control □ Yes □No Iii N/A
□ Landscape/Outdoor Pesticide Use Iii Yes □ No □ N/A
□ Pools, spas, ponds, decorative fountains, and other water features □Yes □ No Iii N/A
□ Food service □ Yes □ No Iii N/A
□ Refuse areas Ill Yes □ No □ N/A
□ Industrial processes Iii Yes □ No □ N/A
□ Outdoor storage of equipment or materials Iii Yes □ No □ N/A
□ Vehicle and Equipment Cleaning □ Yes □ No Iii N/A
□ Vehicle/Equipment Repair and Maintenance □ Yes □ No Iii N/A
□ Fuel Dispensing Areas □ Yes □ No Iii N/A
□ Loading Docks li]Yes □ No □ N/A
□ Fire Sprinkler Test Water Iii Yes □ No □ N/A
□ Miscellaneous Drain or Wash Water Iii Yes □ No □ N/A
□ Plazas, sidewalks, and oarkina lots Iii Yes □ No □ N/A
For "Yes" answers, identify the additional BMP per Appendix E.1. Provide justification for "No" answers .
All items marked "N/A" are features that are not a part of this project.
E-36 Page 2 of 4 Revised 09/16
• • • • • • • • • • • • • • • • • • • • • • • •
• • • • • • • • • • • • •
• • •
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 (Volume 5 of City Engineering Standards) 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. Please add attachments if more space is needed .
• "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 I Applied?
SD-1 Maintain Natural DrainaQe Pathways and HydroloQic Features I D Yes I D No I Iii N/A
Discussion/justification if SD-1 not implemented:
No natural drainage pathways or hydrologic features existing on the site .
SD-2 Conserve Natural Areas, Soils, and Vegetation I Iii Yes I D No ID N/A
Discussion/justification if SD-2 not implemented:
SD-3 Minimize Impervious Area I Iii Yes I D No ID N/A
Discussion/justification if SD-3 not implemented:
SD-4 Minimize Soil Compaction I Iii Yes I D No ID N/A
Discussion/justification if SD-4 not implemented:
SD-5 Impervious Area Dispersion I Iii Yes I D No ID N/A
Discussion/justification if SD-5 not implemented:
E-36 Page 3 of 4 Revised 09/16
• • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • •
Site Dnian Reaulrement (continued) I Applied?
SD-6 Runoff Collection I □Yes I D No I Iii N/A
Discussion/justification if SD-6 not implemented:
Utilizing Worksheet B.3-1 the project is categorized as a Category 5 project, which requires that
"Applicant must implement lined retention BMPs" and capture and use techniques are not required .
SD-7 Landscaping with Native or Drought Tolerant Species I Iii Yes I D No ID NIA
Discussion/justification if SD-7 not implemented:
SD-8 Harvestinq and Usinq Precipitation I D Yes I D No I Iii N/A
Discussion/justification if SD-8 not implemented:
Utilizing Worksheet B.3-1 the project is categorized as a Category 5 project, which requires that
"Applicant must implement lined retention BMPs" and capture and use techniques are not required .
E-36 Page 4 of 4 Revised 09/16
• • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • •
• • •
• •
SUMMARY OF PDP STRUCTURAL BMPS
PDP Structural BMPs
All PDPs must implement structural BMPs for storm water pollutant control (see Chapter 5 of
the BMP Design Manual). Selection of PDP structural BMPs for storm water pollutant control
must be based on the selection process described in Chapter 5. PDPs subject to
hydromodification management requirements must also implement structural BMPs for flow
control for hydromodification management (see Chapter 6 of the BMP Design Manual). Both
storm water pollutant control and flow control for hydromodification management can be
achieved within the same structural BMP(s) .
PDP structural BMPs must be verified by the City at the completion of construction. This may
include requiring the project owner or project owner's representative to certify construction of
the structural BMPs (see Section 1.12 of the BMP Design Manual). PDP structural BMPs must
be maintained into perpetuity, and the City must confirm the maintenance (see Section 7 of the
BMP Design Manual) .
Use this form to provide narrative description of the general strategy for structural BMP
implementation at the project site in the box below. Then complete the PDP structural BMP
summary information sheet for each structural BMP within the project ( copy the BMP summary
information page as many times as needed to provide summary information for each individual
structural BMP) .
Describe the general strategy for structural BMP implementation at the site. This information
must describe how the steps for selecting and designing storm water pollutant control BMPs
presented in Section 5.1 of the BMP Design Manual were followed, and the results (type of
BMPs selected). For projects requiring hydromodification flow control BMPs, indicate whether
pollutant control and flow control BMPs are integrated together or separate .
Self mitigating areas have been identify along the perimeter of the project and a de
minimis area has been identified for the north project driveway .
Harvesting and Re-Use. It was determined that Harvesting and Use of storm water is not
feasible for this project. The City does not have a program for the use of storm water for
toilet and urinal flushing, and re-use of irrigation run-off is not practical given the large
volume of runoff from the site and the limited irrigation demand. Section B.3 of the City
BMP Manual states that Worksheet B.3-1 should be utilized to "evaluate the feasibility of
harvest and use, full retention, and partial retention BMPs ... " Utilizing Worksheet B.3-1
the project is categorized as a Category 5 project, which requires that "Applicant must
implement lined retention BMPs" and capture and use techniques are not required .
[Continue on next page as necessary.]
• • • • • • • • • • •
•
• • • • • • • • • • • • • • •
• • • • • • • • • • • •
[Continued from previous page -This page is reserved for continuation of description of general
strategy for structural BMP implementation at the site.]
Infiltration feasibility (see Attachment I). Infiltration testing was performed by Geocon
Corporation, inc. Infiltration rates were not sufficient to support infiltration type BMPs .
Based on Worksheet B.3-1 and evaluation of site parameters biofiltration basins were
chosen as the structural BMPs for this project for both water quality treatment and
hydromodification .
The biofiltration basin shows as two separate areas on the DMA exhibit and grading
plans. However, the two areas will be connected at the rock layer by an 8 inch PVC
pipe and at the surface elevation by three twelve inch (12") HDPE pipes that will be
place beneath the driveway three inches (3") above the flow line of the biofiltration
basin. The pipe connnections allow the two areas to function as a single biofiltration
basin .
• • • • • • • • • • •
• • • • • • • • • • • • • • • • • • • • • • • •
• • • • • •
Structural BMP Summary Information
[Copy this page as needed to provide information for each Individual proposed
structural BMP]
Structural BMP ID No .
DWG 512-7A Sheet No.
Type of structural BMP:
D Retention by harvest and use (HU-1)
□ Retention by infiltration basin (INF-1)
D Retention by bioretention (INF-2)
4
D Retention by permeable pavement (INF-3)
D Partial retention by biofiltration with partial retention (PR-1)
N:Biofiltration (BF-1)
D 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
D Other (describe in discussion section below)
Purpose:
D Pollutant control only
D Hydromodification control only
Ncombined pollutant control and hydromodification control
□ Pre-treatment/forebay for another structural BMP
□ Other (describe in discussion section below)
Discussion (as needed):
The biofiltration basin is located near the northwest corner of the site and runs
west of the northern project driveway and north of the proposed shell building .
The basin is divided by the north driveway but will function and shall be maintained
as a single basin .
Attachment 1f X IncludedTrash Capture Technical Report
Addendum 1 - 4-18-25
• • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • •
Attachment
Seauence
Attachment 1a
Attachment 1 b
Attachment 1 c
Attachment 1d
Attachment 1 e
ATTACHMENT 1
BACKUP FOR PDP POLLUTANT CONTROL BMPS
This is the cover sheet for Attachment 1 .
Check which Items are Included behind this cover sheet:
Contents
DMA Exhibit (Required)
See DMA Exhibit Checklist on the
back of this Attachment cover sheet.
(24"x36" Exhibit typically required)
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 1 a
Checklist
}[Included
]{Included on DMA Exhibit in
Attachment 1a
□ Included as Attachment 1 b,
separate from DMA Exhibit
Form 1 .. 7, Harvest and Use Feasibility 1Q. Included
Screening Checklist (Required unless □ Not included because the entire
the entire project will use infiltration project will use infiltration BMPs
BMPs)
Refer to Appendix B.3-1 of the BMP
Design Manual to complete Form 1-7 .
Form 1-8, 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 1-8 .
:».included
□ Not included because the entire
project will use harvest and use
BMPs
Pollutant Control BMP Design J{lncluded
Worksheets / Calculations (Required)
Refer to Appendices B and E of the
BMP Design Manual for structural
pollutant control BMP design
guidelines
• • • • • • • • •
•
• • • •
•
•
•
• • • • • • • • • • • • • •
Use this checklist to ensure the required information has been included on the OMA
Exhibit:
The OMA Exhibit must identify:
o Underlying hydrologic soil group
D Approximate depth to groundwater
D Existing natural hydrologic features (watercourses, seeps, springs, wetlands)
D Critical coarse sediment yield areas to be protected (if present)
D Existing topography and impervious areas
D Existing and proposed site drainage network and connections to drainage offsite
D Proposed grading
D Proposed impervious features
o Proposed design features and surface treatments used to minimize imperviousness
D Drainage management area (OMA) boundaries, OMA ID numbers, and OMA areas (square
footage or acreage), and OMA type (i.e., drains to BMP, self-retaining, or self-mitigating)
D Structural BMPs (identify location and type of BMP)
• • • • • • • • • •
•
• • • • • • • • • • • •
• •
• •
• • • • • • •
"'---,
I
If:
OMA AREA TABLE
I. D . AREA(SFJ COMMENTS
PARKING/DRIVE AISLE 29,964
DRIVE AISLE I, 559 DRAINS TO TREE WELL
HARDSCAPEfCONCJ 3,444
ROOF 59, 282
94,249
DRIVEWAY (OFF-SITEJ I. I 9 I POROUS CONCRETE
LANDSCAPE 28.526
SELF Ml T. (EXIST. J 13,373 ...
DE MIN/MUS AREA VARIES
BIOFILTRAT/ON• 3,548
• THE BIOFILTRATION BASIN IS SEPARATED INTO TWO AREAS CONNECTED BY 3-12' HOPE PIPES, 3' ABOVE FLOW LINE AND AN 6' PVC PIPE AT THE ROCK LAYER
ELEVATION THAT ALLOW THE TWO AREAS TO FUNCTION
AS A SINGLE BIOFILTRATION BASIN .
EXISTING SITE CONDTTIONS
UNDEVELOPED MASS GRADED PAD
SOIL GROUP
SOIL TYPED
GROUND WATER
NO GROUND WATER OBSERVED
AT 15' DEPTH .
CRITICAL COARSE SEDIMENT
NO ''STEEP SLOPE LANDS" EXIST
ON-SITE. SITE DOES NOT REC/EVE
ANY RUN-ON FLOW.
~
OMA EXHIBIT
SMAC
~@~y[}={]
1" = 60'
APN 212-120-01
SHEET10F2
AUGUST 8, 2018
1:\9513\DMA EXHIBIT
• • • • • • • • • • • • • • •
• • • • • • • • •
• • • • • • • • • • • • • • •
SELF -MmGA TING AREAS:
-VEGETATION IN THE NATURAL OR LANDSCAPED AREA IS NATIVE
AND/OR NON-NATIVE/NON-INVASIVE DROUGHT TOLERANT SPECIES THAT DO
NOT REQUIRE REGULAR APPLICATION OF FERTILIZERS AND PEST/SIDES .
-SOILS ARE UNDISTURBED NATIVE TOPSOIL, OR DISTURBED SOILS THAT
HAVE BEEN AMENDED PER SD-F
-THE INCIDENTAL IMPERVIOUS AREAS ARE LESS THAN 5 PERCENT OF
THE SELF-MIT/GATING AREA.
-IMPERVIOUS AREA WITHIN THE SELF-MITIGATED AREA SHOULD NOT BE
HYDRAULICALLY CONNECTED TO OTHER IMPERVIOUS AREAS UNLESS IT IS
A STORM WATER CONVEYANCE SYSTEM !SUCH AS A BROW DITCH) .
-THE SELF-MITIGATING AREA IS HYDRAULICALLY SEPARATE FROM DMAs
THAT CONTAIN PERMANENT STORM WATER POLLUTANT CONTROL BMPs .
6" CURB PER
SDRSD G-1 PERVIOUS CONCRETE (3,000 PSI).
15-25% VOIDS
CLASS 4 AB (3/4") 30% VOIDS
COMPACTED TO 95%
6" PERFORATED PVC PIPE
PLACE PERFORATIONS DOWN
L_-+,J;;;~;::;;;.:;:;...~,:;:;~;g_-1 .. ROCK BELOW PIPE.
30 MIL STEGO BRAND STABILIZED SUBGRADE
TYPE WATER STOP LINER COMPACTED TO 95% OF
OR EQUIVALENT. FABRIC THE MODIFIED PROCTOR
TO BE WRAPPED ON /, , /,, MAXIMUM DRY DENSITY PER
BOTTOM AND SIDES OF AASHTO T-180
CLASS 4 AB LA YER MIN. LBR 40
POROUS CONCRETE SECTION
scale: NT S
.."aaicwiia■ ------........-..-----
CD SOIL FILTER MIX
50%SAND
SURFACE PLANTING
SEE LANDSCAPE
PLANS
20% COMPOSTED LEAVES
30% TOPSOIL
5 MIN/IN MINIMUM
PERCOLATION RATE.
® 3"SAND
3" PEA GRAVEL
15" 3/4" WASHED GRAVEL
WOVEN MONOFILAMENT POLYPROPYLENE
GEOTEXTILE WITH A FLOW RATE
GREATER THAN 100 GPM/SF (ASTM D4491)
6" SCH 40 PVC
PERF.PIPE
WIDTH
PER PLAN
t
30 MIL. STEGO BRAND
TYPE WATER STOP LINER
OR EQUIVALENT
BIOFILTRATION BASIN SECTION
(ADJACENT DRIVEWAY)
sca!e N T.S
CD SOIL FILTER MIX
50% SAND
20% COMPOSTED LEAVES
30% TOPSOIL
5 IN/MIN. MINIMUM
PERCOLATION RATE.
® 3"SAND
3" PEA GRAVEL
15" 3/4" WASHED GRAVEL
SURFACE
PLANTING SEE
LANDSCAPE PLANS
WOVEN MONOFILAMENT P
GEOTEXTILE WITH A FLOW RATE
GREATER THAN 100 GPM/SF (ASTM D4491)
6"SCH 40
PVC PERF.
PIPE
WIDTH --.i
PER PLAN
BUILDING FF=245.77
=-y
c'!llt---;,--=:::!._.;;z:___RET. WALL
30MIL
(PER STRUCTURAL
PLANS)
MOISTURE BARRIER
PER GEOTECHNICAL
SPECIFICATIO'IJS
STEGO BRAND TYPE
WATER STOP LINER OR
EQUIVALENT
BIOFIL TRA TION BASIN SECTION
(ADJACENT BUILDING)
scale NT S OMA EXHIBIT
SMAC
APN 212-120-01
SHEET 2 OF 2
August 10, 2018
l:\9513\DMA EXHIBIT
• • • • • • • • • • • • • • • • •
• • • • •
•
• • • • • • • • • • • •
• • •
Category # -
2
3
Stan<lar<l Ill
Drainage Basin
Inputs -6
7
8
9 ---Ill
. • ' . • . ' ..
Description
Drainage Basin ID or Name
Basin Drains to the Following BMP Type
85th Percentile 24-hr Storm Depth
Design Infiltration Rate Recommended by Geotechnical Engineer
lmpe,vious Surfaces Not Directed to Dispersion Area (C=0.90)
Semi-Pervious Surfaces Not Serring as Dispersion Area (C=0.30)
Engineered Pervious Surfaces Not Serving as Dispersion Area (C=0.10)
Natural Type A Soil Not Serving as Dispersion Area (C=0.10)
Natural Type B Soil Noc Serving as Dispersion Area (C=0.14)
Natural Type C Soil Noc Serring as Dispersion Area (C=0.23)
Natural Type D Soil Noc Serving as Dispersion Arca (C=0.30)
Does Tributary Incorporate Dispersion, Tree Wells, and/ or Rain Barrels?
Impervious Surfaces Directed to Dispersion Area per SD-13 (Ci=0.90)
Semi-Pervious Surfaces Serving as Dispersion Area per SD-B (Ci=0.30)
Ill Engineered Pervious Surfaces Serving as Dispersion Area per SD-B (Ci=0.10)
Dispersion Ill
An·a, Tree Well -
& Rain Barrel 11111111:a
Inputs
(Optional) Ill -11D
llfDI El Bl
Treatment El
Train Inputs & m
Calculations lfll
IIEil El
Initial Runoff El
Factor -
Calculation IIJI
1111 El IIDI Dispersion m
Arca
Adjustments ■
El
Tree & Barrel IIIEll
Adjustments IIDI
Rcsuhs
1111 m m 11111
Worksheet B.1-1 General Notes;
Natural Type A Soil Serving as Dispersion Area per SD-B (Ci=0.10)
Natural Type B Soil Serving as Dispersion Area per SD-13 (Ci=0.14)
Natural Type C Soil Serving as Dispersion Area per SD-B (Ci=0.23)
atural Type D Soil Serving as Dispersion Area per SD-B (Ci=0.30)
umber of Tree Wells Proposed per SD-A
Average Mature Tree Canopy Diameter
Number of Rain Barrels Proposed per SD-E
Average Rain Barrel Size
Does BM"P Overflow to Stormwater Features in Downstream Drainage?
Identify Downstream Drainage Basin Providing Treatment in Series
Percent of Upstream Flows Directed to Downstream Dispersion Areas
Upstream Impervious Surfaces Directed to Dispersion Area (Ci=0. 90)
Upstream Impervious Surfaces Not Directed to Dispersion Area (C=0.90)
Total Tributary Area
lrtitial Runoff Factor for Standard Drainage Areas
Initial Runoff Factor for Dispersed & Dispersion Areas
Initial Weighted Runoff Factor
Initial Desii,,n Capture Volume
Total l mpervious Area Dispersed to Pervious Surface
Total Pervious Dispersion Area
Ratio of Dispersed Impervious Arca to Pervious Dispersion Area
AdjustmL'flt Factor for Dispersed & Dispersion Areas
Runoff Factor After Dispersion Techrtiques
Design Capture Volume After Dispersion Techrtiques
Total Tree Well Volume Reduction
Total Rain Barrel Volume Reduction
Final Adjusted Runoff Factor
Final Effective Tributary Area
Initial Design Capture Volume Retained by Site Design Elements
Final Design Capnire Volume Tributary to BMP
/ff Units
IIIIDlilllll
Bio filtration Retention unitless
0.62 0.62 inches
0.000 0.000 in/hr
94,249 1,559 sq-ft
sq-ft
sq-ft
sq-ft
sq-ft
sq-ft
28,526 0 sq-ft
No Yes yes/no
sq-ft
sq-ft
sq-ft
sq-ft
sq-ft
sq-ft
sq-ft
#
1'.3 ft
#
gal
No 0 unitless
unitless
percent
0 0 cubic-feet
0 0 cubic-feet
122,775 1,559 sq-ft
0.76 0.90 unitless
0.00 0.00 urtitless
0.76 0.90 unitless
4,821 72 cubic-feet
0 0 sq-ft
0 0 sq-ft
n/a n/a ratio
1.00 1.00 ratio
0.76 0.90 urtitless
4,821 72 cubic-feet
0 76 cubic-feet
0 0 cubic-feet
0.76 0.00 unitless
93,309 0 sq-ft
0 76 cubic-feet
4,821 0 cubic-feet
n. t\ppucancs may use uus worKsneer to crucware aestgn capture vommes ror up to I u aratnage areas user input musr oe prov1aea ror yeuow snaaea ceus,
values for all other cells will be automatically generated, errors/notifications will be highlighted in red and summarized below. Upon completion of this
wnf'"k .. h,·rt nrnrN•rl tn th,• -,nn ,ntH'1-;1tf' "RMP S1-,1oo-wnrlr-.hrPtf~\
• • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • •
Automated Worksheet B.3-1: Pro·ect-Scale BMP Feasibili
Category
Capture & Use
Inputs
Infiltration
Inputs
#
l!I
2
3
4
5
6
7
8
9
Ill -lfl
Calculations Ill ----Result Ill
Worksheet B.3-1 General Notes:
Description
Design Capture Volume for Entire Project Site
Proposed Development Type
umber of Residents or Employees at 11roposed Development
Total Planted Area within Development
Water Use Category for Proposed Planted Areas
Ts Average Site Design Infiltration Rate :50.500 laches per Hour?
fa Average Site Design Infiltration Rate :50.010 Inches per Hour?
ls Infiltration of the Full DCV Anticipated to Produce Negative Impacts?
Ts Infiltration of Any Volume Anticipated to Produce egative Impacts?
36-1 lour Toilet Use Per Resident or Employee
Subtotal: Anticipated 36 I Iour Toilet Use
Anticipated 1 Acre Landscape Use Over 36 Hours
Subtotal: Anticipated Landscap Use Over 36 I Tours
Total Anticipated Use Over 36 Hours
Total Anticipated Use/ Design Capture Volume
Are Full Capture and Use Techniques Feasible for this Project?
Is Full Retention Feasible for this Project?
Is Partial Retention Feasible for this Project?
Feasibility Category
Value Units
':
Industrial unitless
30 #
41,899 sq-ft
Moderate unitless
cs yes/no
Yes yes/no
0 yes/no
No yes/no
1.10 cubic-feet
33 cubic-feet
196.52 cubic-feet
189 cubic-feet
222 cubic-feet
0.05 cubic-feet
No unitless
0 yes/no
yes/no
5 1,2,3,4,5
A. Applicants may use this worksheet to determine the types of structural BMPs that are acceptable for implementation at their project site (as
required in Section 5 of the BMPDM). User input should be provided for yellow shaded cells, values for all other cells will be automatically
generated. Projects demonstrating feasibility or potential feasibility via this worksheet are encouraged to incorporate capture and use features in
tl1eir project.
B. Negative impacts associated with retention may include geotcchnical, groundwater, water balance, or other issues identified by a geotechnical
engineer and substantiated through completion of Form 1-8 .
C. Feasibility Category 1: Applicant must implement capture & use, retention, and/or infiltration elements for the entire DCV .
D. Feasibility Category 2: Applicant must implement capture & use elements for the entire DCV.
E. Feasibility Category 3: Applicant must implement retention and/or infiltration clements for all DMAs with Design Infiltration Rates greater
than 0.50 in/hr .
r . Feasibility Category 4: Applicant must implement standard unlined biofiltration BMPs sized at ~3% of the effective impervious tributary area
for all DMAs with Design Infiltration Rates of 0.011 to 0.50 in/hr. Applicants may be permitted to implement lined BMPs, reduced size BMPs,
and / or specialized biofiltration BMPs provided additional criteria identified in "Supplemental Retention Criteria for on-Standard Bio filtration
BMPs" are satisfied .
G. Feasibility Category 5: Applicant must implement standard !incl biofiltration BMl's s.ized at ~3% of the effective impervious tributary area
for all DMAs with Design Infiltration Rates of 0.010 in/hr or less. Applicants may also be permitted to implement reduced size and/ or
specialized biofiltration BM11s provided additional criteria identified in "Supplemental Retention Criteria for on-Standard Biofiltration BMPs"
are satisfied.
IL PDPs participating in an offsite altemative compliance program arc not held to the feasibility categories presented herein .
• • • • • • • • • • • • • • • • • • •
• • • • • • • • • • • • • • • • • • • • • • •
I I , • I I •• t • I • I I I I • I I I , I I
Category # Description Units -Drainage Basin ID or Name ---· 1 -Design Infiltration Rate Recommended by Geotechnical Engineer -2 Effective Tributary Area 93,30 sq-ft
3 Minimum Biofiltration Footprint Sizing Factor 0.030 ratio
4 Design Capture Volume Tributary to BMP 4,821 cubic-feet
BMP Inputs 5 ls Biofiltration Basin Impermeably Lined or Unlined? Lined unitless
6 Provided Biofiltration BMP Surface Area 3,548 sq-ft
7 Provided Surface Ponding Depth 6 inches
8 Provided Soil Media Thickness 1 inches
9 Provided Depth of Gravel Above Underdr • nv t 18 ·nches
El Diameter of Underdrain or Hydromod Orifice (Select Smallest) 2.25 inches -Provided Depth of Gravel Below the Underdrain 3 inches -Volume Infiltrated Over 6 Hour Storm 0 cubic-feet -Soil Media Pore Space Available for Retention 0.05 unitless
Ill Gravel Pore Space Available for Retention 0.00 unitless -Effective Retention Depth 0.90 inches
Retention -Calculated Retention Storage Drawdown (Including 6 Hr Storm) 120 hours
Calculations -Volume Retained by BMP 266 cubic-feet
Ill Fraction ofDCV Retained 0.06 ratio -Portion of Retention Performance Standard Satisfied 0.07 ratio
El Fraction ofDCV Retained (normalized to 36-hr drawdown) 0.03 ratio -Design Capture Volume Remaining for Bio tr 0 4,676 cubic-feet
El Max Hydromod Flow Rate through Underdr 0.2454 CFS
El Max Soil Filtration Rate Allowed by Underdrain Orifice 2.99 in/hr -Soil Media Filtration Rate per Specifications 5.00 in/hr
11&1 Soil Media Filtration Rate to be used for Sizing 2.99 in/hr
El Depth Biofiltered Over 6 Hour Storm 17.93 inches -Soil Media Pore Space Available for Biofiltration 0.20 unitless
Effective Depth of Bio filtration Storage 16.80 inches
Drawdown Time for Surface Ponding 2 hours
Drawdown Time for Effective Biofiltration Depth 6 hours
Biofiltration IEII
Calculations El --Total Depth Biofiltered 34.73 inches
El Option 1 -Biofilter 1.50 DCV: Target Volume 7,014 cubic-feet
1111 Option 1 -Provided Biofiltration Volume 7,014 cubic-feet -Option 2 -Store 0.75 DCV: Target Volume 3,507 cubic-feet
El Option 2 -Provided Storage Volume 3,507 cubic-feet -Portion of Bio filtration Performance Standard Satisfied 1.00 ratio -Do Site Design Elements and BMPs Satisfy Annual Retention Requirements? Yes yes/no
Overall Portion of Perfonnance Standard Satisfied 1.00 ratio
This BMP Overflows to the Fol.lowing Drainage Basin unit.less
Result El --Deficit of Effectively Treated Stormwater 0 cubic-feet
Worksheet B.5-1 General Notes:
A. Applicants may use this worksheet to size Lined or Unlined Biofilt.ration BivIPs (BF-1, PR-1) for up to 10 basins. User input must be
provided for yellow shaded cells, values for blue cells are automatically populated based on user inputs from previous worksheets, values for
all other cells will be automatically generated, errors/notifications will be highlighted in red/orange and summarized below. BMPs fully
I r , •
TECHNICAL REPORT
Hydraulic Design of Screen for Trash
Capture in Basin
FARADAY INDUSTRIAL / VAN ALLEN WAY
5801 Van Allen Way
Carlsbad, CA 92008
Prepared For:
KARN Engineering and Surveying, Inc.
December 20, 2024.
Revised: April 28, 2025
Prepared by:
Luis Parra, PhD, CPSWQ, ToR, D.WRE.
R.C.E. 66377
REC Consultants
2970 Fifth Avenue, Suite 340
San Diego, CA 92103
Telephone: (619) 232-9200
REC
Consultants, Inc.
1
HYDRAULIC DESIGN OF A SCREEN FOR TRASH CAPTURE IN UPSTREAM END OF
BIOFILTRATION BASIN FOR 5801 VAN ALLEN WAY, CARLSBAD, CA, 92008
Date: 12/20/2024
Revised: 4/28/2025
1. ANTECEDENTS
The purpose of this analysis is to design a trash capture device just downstream of the inlet pipes
discharging into the biofiltration basin for the Faraday Industrial / Van Allen Way project on 5801 Van
Allen Way, Carlsbad, CA. Screen Trash Capture (STC) devices are designed upstream of the outlet structure
because by adding a trash screen at the outlet of the basin the discharge behavior of the basin is affected
and the basin was carefully calibrated for water quality and hydromodification compliance. Also, trash
capture devices might impact negatively flood control conditions and safety factors when placed adjacent
to the outlet structure of basins. An important note for the design is that the trash capture device designed
in this report will more than satisfy trash capture requirements, as the new grading is less than 10,000 ft2
(not even a PDP) but the system designed traps the trash for an area over 124,000 sq-ft (2.875 acres).
2. DRAINAGE AREAS AND PEAK FLOWS
Figure 1 shows the location of the Screen Trash Capture (STC) device, while Table 1 shows the main
characteristics of the contributing area to obtain the trash capture flow. The intensity of design is
equivalent to the NOAA 14 1-hour, 1-year intensity (0.421 in/hr at the project site). The C coefficient and
contributing area were obtained from REC Drainage Report analysis (reference [1]). The Qtrash is simply
obtained with the Rational Method as Q = C·I·A.
In regards to the 100 year peak flow, the value obtained from the drainage report [1] is shown in Table 1
below.
Table 1. Peak Flows
Area (ac) C Coefficient I (in/hr) Qtrash (cfs) Q100 (cfs)(1)
2.857 0.9 0.421 1.083 14.614
Notes: (1): Q100 peak flow obtained from [1] 100-Yr Routing Analysis for Faraday Industrial
The STC device must be able to (a) allow the flow Qtrash to pass through without any by-pass, and (b) allow
the safe passage of Q100 without impacting flooding conditions upstream. A detailed methodologic
approach will be explained in the next section.
REC
Consultants, Inc.
FARADAY INDUSTRIAL / VAN ALLEN WAY, HMP AND 100 YEAR DETENTION FACILITY
Screen for Tash Capture. December 20, 2024, revised April 28, 2025
2
TRASH CAPTURE SCREEN
FIGURE 1. Location of Screen Trash Capture Device
FARADAY INDUSTRIAL / VAN ALLEN WAY, HMP AND 100 YEAR DETENTION FACILITY
Screen for Tash Capture. December 20, 2024, revised April 28, 2025
3
3. HYDRAULIC DESIGN OF TRASH SCREEN IN BIOFILTRATION BASIN
Based on reference [2] submitted and approved by the State Water Board, and taking into account
hydraulic equations related to weir and orifice equations (reference [3], among many others), the
following is the detailed methodology for trash screen design in the biofiltration basin.
Figure 2: Hydraulic Design of Trash Screen
∆Hscreen, 100
Scenario 2 ∆Hscreen, 100 Qweir Scenario 1
Htotal, 100
QweirQorif2
H100,p H100,p Qorif1
∆Hscreen, 1QorifHscreen = 1 ft Htotal, 1
Q1
Q100 Peak flow with associated elevation (scenario 1)
Q100 Peak elevation with associated flow (scenario 2)
Qtrash
* Note: Q100 for scenario 2 has a higher downstream elevation than screen height, therefore has
an additional orifice flow above the trash screen but below the WSE.
Hydraulic Design of Trash Screen
H1,p
Vertical Trash Screen
REC
Consultants, Inc.
+-
j7j
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VI I /1
r/~.--------
:1/. ----=:;::::,-==~--~-
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FARADAY INDUSTRIAL / VAN ALLEN WAY, HMP AND 100 YEAR DETENTION FACILITY
Screen for Tash Capture. December 20, 2024, revised April 28, 2025
4
3.1 Downstream Requirements: Scenarios
In reference to Figure 2, the trash capture device must be designed in accordance to three different cases.
First, the device must be able to allow the Qtrash to pass through without any by-pass. Qtrash is shown in
cyan in Figure 2. Second, the device must allow safe passage of the peak Q100 flow with associated
elevation (maximum peak during routing with corresponding elevation) while maintaining a free board in
the basin. This is referenced as Q100 Scenario 1 in Figure 2 and is represented by dark blue. The final
scenario is referred to as Q100 Scenario 2 and analyzes the condition of the peak Q100 elevation with its
associated flowrate (maximum elevation during routing with corresponding peak). Q100 Scenario 2 is
represented by green in Figure 2. Note that in Q100 Scenario 2 the downstream elevation is higher than
that of the top of screen. Therefore, Q100 Scenario 2 has an additional orifice flow above the screen but
below the water surface elevation. The reader should be aware that the maximum inlet peak flow and the
maximum elevation in the pond are not simultaneous because the outflow peak = maximum elevation
occurs after the inflow peak.
3.2 Screen Design for Trash Flow
Once Qtrash is known, the height of the screen Hscreen and its length Lscreen must be provided. REC selected
a screen with a length of 16 ft and a height of 1ft.
The energy loss through the screen, ∆Hscreen is then calculated with the orifice equation, under the
following assumptions: the screen opening is typically 44% of the total area, and the clogging factor is
typically 50%, meaning that only 22% of the entire Ascreen (Lscreen x Hscreen) is available for flow. Those
screen and clogging assumptions were taken directly from [2]. In addition, the discharge coefficient of the
screen CD,screen was experimentally determined from [2] and conservatively assumed as 0.53. This is the
value we will use in equation (3.2).
𝐴௦ =𝑄௧
൫0.22 · 𝐶,௦൯ඥ2𝑔 · ∆𝐻௦
(3.2)
For the 1 year – 1 hour intensity, adding the ∆Hscreen,1 to the water surface elevation, H1,p , retrieved from
the drainage report associated with a flowrate equivalent to the Qtrash allow us to obtain the required
upstream level of ponding Htotal,1, which must be lower than the screen height.
The reader should be aware that the screen designed with this methodology will have enough hydraulic
capacity to treat Qtrash with the intrinsic assumptions associated with the design (44% opening area, 50%
clogged area). For Qtrash, there will be no over-flow over the screen, as it is assumed that the screen will
be properly maintained and will be never be clogged in excess of 50%.
REC
Consultants, Inc.
FARADAY INDUSTRIAL / VAN ALLEN WAY, HMP AND 100 YEAR DETENTION FACILITY
Screen for Tash Capture. December 20, 2024, revised April 28, 2025
5
Table 2 shows the trash screen to be designed in this report, while Figure 3 shows a schematic plan view
of the design.
Figure 3: Trash Screen Dimensions
TRASH SCREEN DESIGN
L=16 ft
H=1 ft
RIP RAP
8" pipe
18" pipe
239
238
238.5
REC
Consultants, Inc.
FARADAY INDUSTRIAL / VAN ALLEN WAY, HMP AND 100 YEAR DETENTION FACILITY
Screen for Tash Capture. December 20, 2024, revised April 28, 2025
6
Table 2. Design for Trash Flow Conditions
Qtrash (cfs) Htotal, 1 (1)
(ft)
H1,P (2)
(ft)
∆Hscreen, 1 (3)
(ft)
Ascreen
(required)
(ft2)
Ascreen
(Provided)
(ft2)
Lscreen
(ft)
Hscreen
(ft)
1.083 0.256 0.176 0.080 4.09 16 16 1
Notes: (1): Htotal, 1 = The peak depth upstream of the screen during the 1-year storm event.
(2): H1,P = The peak depth downstream of the screen during the 1-year storm event.
(3): ∆Hscreen, 1 = Energy loss through the screen (Htotal, 1 -H1,P = ∆Hscreen, 1)
3.3 Review of the Screen Design for Extreme Event: Overflow Design
Typically, the 100-year flood event should be able to flow through the trash screen safely while
maintaining a free board in the basin, and should be able to not create flooding conditions upstream, by
significantly obstructing the flow and creating ponding levels above grade.
The required upstream level of ponding was designed lower than Hscreen for Qtrash, so it not requires
further calculation for the design trash flow. However, the required upstream level of ponding Htotal,100 is
larger than Hscreen when the peak flow is Q100. Therefore, a detailed discharge equation is needed. When
the downstream water level H100,p is larger than Hscreen, the discharge of Q100 is accomplished thru three
(3) portions: discharge thru the screen, discharge above the screen via orifice equation associated with
the orifice area: Height (above screen but below H100,p) x length of screen, and weir discharge via surface
difference of elevation ∆Hscreen, 100. The resulting discharge equation is then:
𝑄ଵ = ቀ൫0.61𝐻ଵ, − (0.53 · 0.22 − 0.61)𝐻௦൯𝐿௩ௗௗቁ ඥ2𝑔 · ∆𝐻௦,ଵ + 3.1 · 𝐿௩ௗௗ(∆𝐻௦)ଷ/ଶ
(valid only if H100,p ≥ Hscreen) (3.3.1)
If the downstream elevation, H100,p , during the occurrence of Q100 is less than Hscreen then the orifice
equation through the screen plus the weir equation above the screen will be sufficient to describe the
discharge of the extreme event. This second scenario does not occur in any of the conditions designed in
this report.
𝑄ଵ = 0.22 · 0.53 · 𝐻௦ · 𝐿௩ௗௗඥ2𝑔 · ∆𝐻௦ + 3.1 · 𝐿௩ௗௗ൫𝐻௧௧,ଵ − 𝐻௦൯ଷ/ଶ
(valid only if H100,p < Hscreen) (3.3.2)
Finally, the final confirmation is related with the Free-board (FB). FB must be larger than 0, and it is equal
to the crest of the basin which is at an elevation of 1.5 ft minus the height of the upstream level of ponding
Htotal,100. FB = 1.5 – Htotal,100. From Table 3, FB > 0.25 for the two worst case scenarios analyzed while
discharging Q100.
Tables 3 and 4 show the results of the designs related to the two scenarios for Q100.
REC
Consultants, Inc.
FARADAY INDUSTRIAL / VAN ALLEN WAY, HMP AND 100 YEAR DETENTION FACILITY
Screen for Tash Capture. December 20, 2024, revised April 28, 2025
7
Table 3. Design Review for Q100 Flow Conditions (Peak Q100 Inflow and Associated Elev.)
Q100
(cfs)
Ascreen (Provided)
(ft2)
Lscreen
(ft)
Hscreen
(ft)
∆Hscreen, 1 (3)
(ft)
H100,P (2)
(ft)
Htotal, 100 (1)
(ft) FB (ft)
14.614 16 16 1 0.322 0.926 1.248 0.252
Notes: 1: Htotal, 100 = The peak depth upstream of the screen during the 100-year storm event.
2: H100,P = The peak depth downstream of the screen during the 100-year storm event.
3: ∆Hscreen, 100 = Energy loss through the screen during the 100-year storm event.
(Htotal, 100 -H100,P = ∆Hscreen, 100)
Table 4. Design Review for Q100 Flow Conditions (Peak Q100 Elev. and Associated Inflow)
Q100
(cfs)
Ascreen (Provided)
(ft2)
Lscreen
(ft)
Hscreen
(ft)
∆Hscreen, 1 (3)
(ft)
H100,P (2)
(ft)
Htotal, 100 (1)
(ft) FB (ft)
5.420 16 16 1 0.026 1.223 1.249 0.251
Notes: 1: Htotal, 100 = The peak depth upstream of the screen during the 100-year storm event.
2: H100,P = The peak depth downstream of the screen during the 100-year storm event.
3: ∆Hscreen, 100 = Energy loss through the screen during the 100-year storm event.
(Htotal, 100 -H100,P = ∆Hscreen, 100)
3.4 Summary of Design Dimensions related to the Screen
Table 5 summarizes the dimensions for Hscreen (screen height) and Lprovided (total plan-view length of the
screen provided).
TABLE 5. Design Dimensions for STC
STC ID Hscreen (ft) Lprovided (ft)
1 1.0 16.0
4. TRASH RELATED DESIGN WHERE THE SCREEN WILL BE PLACED
4.1 Estimate of Trash Generation (gallon/acre/yr)
Without specific measurements there is no accurate manner to determine the expected trash generating
capacity of the upstream areas of the Faraday industrial / 5801 Van Allen Way Project (gallons of
trash/acre/year). However, there are many factors in terms of land use that lead REC to use a conservative
value:
The Faraday Industrial / 5801 Van Allen Way project is located in an area considered to have a
moderate baseline trash score.
The project’s land use is considered as Commercial – Not Retail.
REC
Consultants, Inc.
I I I I I I
I I I I I I I
FARADAY INDUSTRIAL / VAN ALLEN WAY, HMP AND 100 YEAR DETENTION FACILITY
Screen for Tash Capture. December 20, 2024, revised April 28, 2025
8
REC decided to use a local Oceanside study (reference [5]) but not to use downtown values included there,
but rather commercial – non retail values. Per Oceanside [5], we should expect about 6.2 gallon/acre/year
(commercial, not retail). Per trash hot-spot map [4], the project site isn’t located within a “Hot-Spot”.
Therefore, REC decided to use the value of 6.2 gallon/acre/year of trash obtained from the standard
Oceanside Reference.
4.2 Calculation of Trash Volume Arriving at Basin
REC knows the approximate area A (acres) contributing to the basin where the trash capture devices will
be incorporated. The following are the list of assumptions for calculation:
Trash porosity n = 0.4: the volume of trash must be increased to account for lack of compaction
Trash Generation constant of TG = 6.2 gallon/acre/year
Frequency of Trash Removal (FTR) of approximately 2 times a year: once before the wet season
of Nov – April (highest rain typically December, January, and February), and once after the wet
season.
The expected volume of trash (Vtrash, ft3), accumulated in between cleaning operations can be obtained
with the following equation:
𝑉௧௦ =𝐴 · 𝑇𝐺
7.48 · 𝐹𝑇𝑅(1 − ƞ)
(4.2.1)
The available volume for trash capture is the area in between the 238.5 contour and the trash screen,
Asc,plan, (see Figure 3) multiplied by the height of the trash screen:
𝑉௩ = 𝐴௦, ∗ 𝐻௦
(4.2.2)
Table 6 shows the expected volume with the recommended trash removal frequency of 2 per year along
with the available volume with the proposed trash screen.
TABLE 6. Trash Volume at Trash Screen
Frequency of Trash
Removal (FTR)
Vtrash
(ft3)
Asc,plan
(ft2)
Hscreen
(ft)
Vavailable
(ft3)
2 / year 1.973 130.43 1 130.43
5. SUMMARY
REC
Consultants, Inc.
FARADAY INDUSTRIAL / VAN ALLEN WAY, HMP AND 100 YEAR DETENTION FACILITY
Screen for Tash Capture. December 20, 2024, revised April 28, 2025
9
The trash screen will be a 16’ long – 12” tall screen in the biofiltration basin, just downstream of the storm
drains outlet into the basin. This screen will control the trash of the entire 2.857 acre site (much more
than required by the non-PDP re-grading project, where the contributing area is less than 10,000 sq-ft).
The trash can must be placed against the slope and in such a way that the water out of the pipes cannot
reach the outlet of the basin without first going thru the trash screen.
The screen will be subject to trash cleaning as follows:
One time prior to the rainy season: October or November
One time after the end of the rainy season: March to April
6. TYPICAL SCREEN MODELS
Appendix 1 shows an approved example of a screen. No specific manufacturer is recommended, as long
as the screen to be installed is listed among the State Water Board approved list for trash screens, but
with the dimensions designed in this report (and not with the dimensions recommended by the
manufacturer).
7. REFERENCES
[1] Hydrology Report: 100-Year Routing Analysis for Faraday Industrial, City of Carlsbad. REC
Consultants, Inc. Revised: Aug. 28, 2018.
[2] Technical Report: Connector Pipe Screen Design. Full Capture TMDL Compliance Screen and By-
Pass Sizing Requirements. County of Los Angeles Dpt. Of Public Works. April, 2007.
[3] French, Richard: Open Channel Hydraulics. McGraw Hill, 1985.
[4] Trash Free Carlsbad: https://storymaps.arcgis.com/stories/829857179b3843bfac18382f4a8edf65
[5] DMAX Engineering Inc.: City of Oceanside: Compliance Track Evaluation for The Statewide Trash
Amendments. July 2017.
REC
Consultants, Inc.
AUGUST 8 , 2018
1" = 60'
I:\9513\DMA EXHIBIT
EXISTING SITE CONDITIONS
UNDEVELOPED MASS GRADED PAD
SOIL GROUP
SOIL TYPE D
GROUND WATER
NO GROUND WATER OBSERVED
AT 15' DEPTH.
CRITICAL COARSE SEDIMENT
NO "STEEP SLOPE LANDS" EXIST
ON-SITE. SITE DOES NOT RECIEVE
ANY RUN-ON FLOW.
NO SCALE
POROUS CONCRETE SECTION
I
DMA AREA TABLE
I. D.
PARKING/DRIVE AISLE
DRIVE AISLE
HARDSCAPE!CONC!
ROOF
IMPERVIOUS TOTAL:
DRIVEWAY !OFF-SITE!
LANDSCAPE
SELF MITIGATING
DIMINIMUS AREA
BIOFI LTRATION•
AREA/SF! COMMENTS
29,964
I, 559 DRAINS TO TREE WELL
3,444
59,282
94,249
I, 191 POROUS CONCRETE
28,526
13,373
245
3,339
• THE BIOFILTRATION BASIN IS SEPARATED INTO TWO AREAS CONNECTED BY 3-12' HDPE PIPES, 3' ABOVE
FLOW LINE AND AN 6' PVC PIPE AT THE ROCK LAYER
ELEVATION THAT ALLOW THE TWO AREAS TO FUNCTION
AS A SINGLE BIOFILTRATION BASIN.
30 MIL STEGO BRAND
TYPE WATER STOP LINER
OR EQUIVALENT. FABRIC
TO BE WRAPPED ON
BOTTOM AND SIDES OF
CLASS 4 AB LAYER
POROUS CONCRETE (3,000 PSI).
15-25% VOIDS
CLASS 4 AB (3/4") 30% VOIDS
COMPACTED TO 95%
6" PERFORATED PVC PIPE
STABILIZED SUBGRADE
COMPACTED TO 95% OF
THE MODIFIED PROCTOR
MAXIMUM DRY DENSITY PER
AASHTO T-180.
OMA EXHIBIT
SMAC
APN 212-120-01
SHEET10F2