Water Quality Management Plan

For:

Insert Project Name

where applicable, insert Grading Permit No., Building Permit No., Tract Number, Land development file no., CUP, SUP and/or APN (Specify Lot Numbers if site is a portion of a Tract)

Prepared for:

Insert Owner/Developer Name

Insert Address

Insert City, State, ZIP

Insert Telephone

Prepared by:

Insert Consulting/Engineering Firm Name

Insert Address

Insert City, State, ZIP

Insert Telephone

Submittal Date: Insert Initial Submittal Date

Revision Date: Insert Current Revision Date

Approval Date:_____________________

Project Owner’s Certification

This Water Quality Management Plan (WQMP) has been prepared for Insert Owner/Developer Name by Insert Consulting/Engineering Firm Name. The WQMP is intended to comply with the requirements of the Insert Jurisdiction and the NPDES Areawide Stormwater Program requiring the preparation of a WQMP. The undersigned, while it owns the subject property, is responsible for the implementation of the provisions of this plan and will ensure that this plan is amended as appropriate to reflect up-to-date conditions on the site consistent with San Bernardino County’s Municipal Storm Water Management Program and the intent of the NPDES Permit for San Bernardino County and the incorporated cities of San Bernardino County within the Santa Ana Region. Once the undersigned transfers its interest in the property, its successors in interest and the city/county shall be notified of the transfer. The new owner will be informed of its responsibility under this WQMP. A copy of the approved WQMP shall be available on the subject site in perpetuity.

“I certify under a penalty of law that the provisions (implementation, operation, maintenance, and funding) of the WQMP have been accepted and that the plan will be transferred to future successors.”

.

Project Data
Permit/Application Number(s):	Grading Permit Number(s):
Tract/Parcel Map Number(s):	Building Permit Number(s):
CUP, SUP, and/or APN (Specify Lot Numbers if Portions of Tract):
Owner’s Signature
Owner Name:
Title
Company
Address
Email
Telephone #
Signature	Date

Preparer’s Certification

Project Data
Permit/Application Number(s):	Grading Permit Number(s):
Tract/Parcel Map Number(s):	Building Permit Number(s):
CUP, SUP, and/or APN (Specify Lot Numbers if Portions of Tract):

“The selection, sizing and design of stormwater treatment and other stormwater quality and quantity control

measures in this plan were prepared under my oversight and meet the requirements of Regional Water Quality Control Board Order No. R8-2010-0036.”

Engineer:	PE Stamp Below
Title
Company
Address
Email
Telephone #
Signature
Date

Table of Contents

Section 1	Discretionary Permits	1-1

Section 2 Project Description	2-1

2.1 Project Information	2-1

2.2 Property Ownership / Management	2-2

2.3 Potential Stormwater Pollutants	2-3

2.4 Water Quality Credits	…………………………………………………………………………….	2-4

Section 3	Site and Watershed Description	3-1

Section 4	Best Management Practices	4-1

4.1 Source Control BMP	4-1

4.1.1 Pollution Prevention	4-1

4.1.2 Preventative LID Site Design Practices	4-6

4.2 Project Performance Criteria	4-7

4.3 Project Conformance Analysis	4-12

4.3.1 Site Design Hydrologic Source Control BMP	4-14

4.3.2 Infiltration BMP	4-16

4.3.3 Harvest and Use BMP	4-18

4.3.4 Biotreatment BMP	4.19

4.3.5 Conformance Summary	4-23

4.3.6 Hydromodification Control BMP	4-24

4.4 Alternative Compliance Plan (if applicable)	4-25

Section 5	Inspection & Maintenance Responsibility Post Construction BMPs	5-1

Section 6	Site Plan and Drainage Plan	6-1

6.1. Site Plan and Drainage Plan	6-1

6.2 Electronic Data Submittal	6-1

Forms

Form 1-1 Project Information	1-1

Form 2.1-1 Description of Proposed Project	2-1

Form 2.2-1 Property Ownership/Management	2-2

Form 2.3-1 Pollutants of Concern	2-3

Form 2.4-1 Water Quality Credits	2-4

Form 3-1 Site Location and Hydrologic Features	3-1

Form 3-2 Hydrologic Characteristics	3-2

Form 3-3 Watershed Description	3-3

Form 4.1-1 Non-Structural Source Control BMP	4-2

Form 4.1-2 Structural Source Control BMP	4-4

Form 4.1-3 Site Design Practices Checklist	4-6

Form 4.2-1 LID BMP Performance Criteria for Design Capture Volume	4-7

Form 4.2-2 Summary of HCOC Assessment	4-8

Form 4.2-3 HCOC Assessment for Runoff Volume	4-9

Form 4.2-4 HCOC Assessment for Time of Concentration	4-10

Form 4.2-5 HCOC Assessment for Peak Runoff	4-11

Form 4.3-1 Infiltration BMP Feasibility	4-13

Form 4.3-2 Site Design Hydrologic Source Control BMP	4-14

Form 4.3-3 Infiltration LID BMP	4-17

Form 4.3-4 Harvest and Use BMP	4-18

Form 4.3-5 Selection and Evaluation of Biotreatment BMP	4-19

Form 4.3-6 Volume Based Biotreatment – Bioretention and Planter Boxes w/Underdrains	4-20

Form 4.3-7 Volume Based Biotreatment- Constructed Wetlands and Extended Detention	4-21

Form 4.3-8 Flow Based Biotreatment	4-22

Form 4.3-9 Conformance Summary and Alternative Compliance Volume Estimate	4-23

Form 4.3-10 Hydromodification Control BMP	4-24

Form 5-1 BMP Inspection and Maintenance	5-1

Insert Appendix Title if Applicable - Otherwise, please delete text

Insert Appendix Title if Applicable - Otherwise, please delete text

Insert Appendix Title if Applicable - Otherwise, please delete text

Insert Appendix Title if Applicable - Otherwise, please delete text

Insert Appendix Title if Applicable - Otherwise, please delete text

Section 1	Discretionary Permit(s)

Form 1-1 Project Information
Project Name
Project Owner Contact Name:
Mailing Address:	E-mail Address:	Telephone:
Permit/Application Number(s):	Tract/Parcel Map Number(s):
Additional Information/ Comments:
Description of Project:
Provide summary of Conceptual WQMP conditions (if previously submitted and approved). Attach complete copy.

Section 2	Project Description

2.1	Project Information

This section of the WQMP should provide the information listed below. The information provided for Conceptual/ Preliminary WQMP should give sufficient detail to identify the major proposed site design and LID BMPs and other anticipated water quality features that impact site planning. Final Project WQMP must specifically identify all BMP incorporated into the final site design and provide other detailed information as described herein.

The purpose of this information is to help determine the applicable development category, pollutants of concern, watershed description, and long term maintenance responsibilities for the project, and any applicable water quality credits. This information will be used in conjunction with the information in Section 3, Site Description, to establish the performance criteria and to select the LID BMP or other BMP for the project or other alternative programs that the project will participate in, which are described in Section 4.

Form 2.1-1 Description of Proposed Project
1 Development Category (Select all that apply):
Significant re-development involving the addition or replacement of 5,000 ft2 or more of impervious surface on an already developed site	New development involving the creation of 10,000 ft2 or more of impervious surface collectively over entire site	Automotive repair shops with standard industrial classification (SIC) codes 5013, 5014, 5541, 7532- 7534, 7536-7539	Restaurants (with SIC code 5812) where the land area of development is 5,000 ft2 or more
Hillside developments of 5,000 ft2 or more which are located on areas with known erosive soil conditions or where the natural slope is 25 percent or more	Developments of 2,500 ft2 of impervious surface or more adjacent to (within 200 ft) or discharging directly into environmentally sensitive areas or waterbodies listed on the CWA Section 303(d) list of impaired waters.	Parking lots of 5,000 ft2 or more exposed to storm water	Retail gasoline outlets that are either 5,000 ft2 or more, or have a projected average daily traffic of 100 or more vehicles per day
Non-Priority / Non-Category Project May require source control LID BMPs and other LIP requirements. Please consult with local jurisdiction on specific requirements.
2 Project Area (ft2):	3 Number of Dwelling Units:	4 SIC Code:
5 Is Project going to be phased? Yes No If yes, ensure that the WQMP evaluates each phase as a distinct DA, requiring LID BMPs to address runoff at time of completion.
6 Does Project include roads? Yes No If yes, ensure that applicable requirements for transportation projects are addressed (see Appendix A of TGD for WQMP)

2.2	Property Ownership/Management

Describe the ownership/management of all portions of the project and site. State whether any infrastructure will transfer to public agencies (City, County, Caltrans, etc.) after project completion. State if a homeowners or property owners association will be formed and be responsible for the long-term maintenance of project stormwater facilities. Describe any lot-level stormwater features that will be the responsibility of individual property owners.

Form 2.2-1 Property Ownership/Management
Describe property ownership/management responsible for long-term maintenance of WQMP stormwater facilities:

2.3	Potential Stormwater Pollutants

Determine and describe expected stormwater pollutants of concern based on land uses and site activities (refer to Table 3-3 in the TGD for WQMP).

Form 2.3-1 Pollutants of Concern
Pollutant	Please check: E=Expected, N=Not Expected	Additional Information and Comments
Pathogens (Bacterial / Virus)	E	N
Nutrients - Phosphorous	E	N
Nutrients - Nitrogen	E	N
Noxious Aquatic Plants	E	N
Sediment	E	N
Metals	E	N
Oil and Grease	E	N
Trash/Debris	E	N
Pesticides / Herbicides	E	N
Organic Compounds	E	N
Other:	E	N
Other:	E	N
Other:	E	N
Other:	E	N
Other:	E	N

2.4	Water Quality Credits

A water quality credit program is applicable for certain types of development projects if it is not feasible to meet the requirements for on-site LID. Proponents for eligible projects, as described below, can apply for water quality credits that would reduce project obligations for selecting and sizing other treatment BMP or participating in other alternative compliance programs. Refer to Section 6.2 in the TGD for WQMP to determine if water quality credits are applicable for the project.

Form 2.4-1 Water Quality Credits
1 Project Types that Qualify for Water Quality Credits: Select all that apply
Redevelopment projects that reduce the overall impervious footprint of the project site. [Credit = % impervious reduced]	Higher density development projects Vertical density [20%] 7 units/ acre [5%]	Mixed use development, (combination of residential, commercial, industrial, office, institutional, or other land uses which incorporate design principles that demonstrate environmental benefits not realized through single use projects) [20%]	Brownfield redevelopment (redevelop real property complicated by presence or potential of hazardous contaminants) [25%]
Redevelopment projects in established historic district, historic preservation area, or similar significant core city center areas [10%]	Transit-oriented developments (mixed use residential or commercial area designed to maximize access to public transportation) [20%]	In-fill projects (conversion of empty lots & other underused spaces < 5 acres, substantially surrounded by urban land uses, into more beneficially used spaces, such as residential or commercial areas) [10%]	Live-Work developments (variety of developments designed to support residential and vocational needs) [20%]
2 Total Credit % (Total all credit percentages up to a maximum allowable credit of 50 percent)
Description of Water Quality Credit Eligibility (if applicable)

Section 3	Site and Watershed Description

Describe the project site conditions that will facilitate the selection of BMP through an analysis of the physical conditions and limitations of the site and its receiving waters. Identify distinct drainage areas (DA) that collect flow from a portion of the site and describe how runoff from each DA (and sub-watershed DMAs) is conveyed to the site outlet(s). Refer to Section 3.2 in the TGD for WQMP. The form below is provided as an example. Then complete Forms 3.2 and 3.3 for each DA on the project site. If the project has more than one drainage area for stormwater management, then complete additional versions of these forms for each DA / outlet.

Form 3-1 Site Location and Hydrologic Features
Site coordinates take GPS measurement at approximate center of site	Latitude	Longitude	Thomas Bros Map page
1 San Bernardino County climatic region: Valley Mountain
2 Does the site have more than one drainage area (DA): Yes No If no, proceed to Form 3-2. If yes, then use this form to show a conceptual schematic describing DMAs and hydrologic feature connecting DMAs to the site outlet(s). An example is provided below that can be modified for proposed project or a drawing clearly showing DMA and flow routing may be attached
Outlet 1 DA1 DMA A DA1 DMA C DA 1 DMA B Outlet 2 DA2 Example only – modify for project specific WQMP using additional form
Conveyance	Briefly describe on-site drainage features to convey runoff that is not retained within a DMA
DA1 DMA C flows to DA1 DMA A	Ex. Bioretention overflow to vegetated bioswale with 4’ bottom width, 5:1 side slopes and bed slope of 0.01. Conveys runoff for 1000’ through DMA 1 to existing catch basin on SE corner of property
DA1 DMA A to Outlet 1
DA1 DMA B to Outlet 1
DA2 to Outlet 2

Form 3-2 Existing Hydrologic Characteristics for Drainage Area 1
For Drainage Area 1’s sub-watershed DMA, provide the following characteristics	DMA A	DMA B	DMA C	DMA D
1 DMA drainage area (ft2)
2 Existing site impervious area (ft2)
3 Antecedent moisture condition For desert areas, use http://www.sbcounty.gov/dpw/floodcontrol/pdf/20100412_map.pdf
4 Hydrologic soil group Refer to Watershed Mapping Tool – http://permitrack.sbcounty.gov/wap/
5 Longest flowpath length (ft)
6 Longest flowpath slope (ft/ft)
7 Current land cover type(s) Select from Fig C-3 of Hydrology Manual
8 Pre-developed pervious area condition: Based on the extent of wet season vegetated cover good >75%; Fair 50-75%; Poor <50% Attach photos of site to support rating

Form 3-2 Existing Hydrologic Characteristics for Drainage Area 1 (use only as needed for additional DMA w/in DA 1)
For Drainage Area 1’s sub-watershed DMA, provide the following characteristics	DMA E	DMA F	DMA G	DMA H
1 DMA drainage area (ft2)
2 Existing site impervious area (ft2)
3 Antecedent moisture condition For desert areas, use http://www.sbcounty.gov/dpw/floodcontrol/pdf/20100412_map.pdf
4 Hydrologic soil group Refer to Watershed Mapping Tool – http://permitrack.sbcounty.gov/wap/
5 Longest flowpath length (ft)
6 Longest flowpath slope (ft/ft)
7 Current land cover type(s) Select from Fig C-3 of Hydrology Manual
8 Pre-developed pervious area condition: Based on the extent of wet season vegetated cover good >75%; Fair 50-75%; Poor <50% Attach photos of site to support rating

Form 3-3 Watershed Description for Drainage Area
Receiving waters Refer to Watershed Mapping Tool - http://permitrack.sbcounty.gov/wap/ See ‘Drainage Facilities” link at this website
Applicable TMDLs Refer to Local Implementation Plan
303(d) listed impairments Refer to Local Implementation Plan and Watershed Mapping Tool – http://permitrack.sbcounty.gov/wap/ and State Water Resources Control Board website – http://www.waterboards.ca.gov/santaana/water_issues/programs/tmdl/index.shtml
Environmentally Sensitive Areas (ESA) Refer to Watershed Mapping Tool – http://permitrack.sbcounty.gov/wap/
Unlined Downstream Water Bodies Refer to Watershed Mapping Tool – http://permitrack.sbcounty.gov/wap/
Hydrologic Conditions of Concern	Yes Complete Hydrologic Conditions of Concern (HCOC) Assessment. Include Forms 4.2-2 through Form 4.2-5 and Hydromodification BMP Form 4.3-10 in submittal No
Watershed–based BMP included in a RWQCB approved WAP	Yes Attach verification of regional BMP evaluation criteria in WAP More Effective than On-site LID Remaining Capacity for Project DCV Upstream of any Water of the US Operational at Project Completion Long-Term Maintenance Plan No

Section 4	Best Management Practices (BMP)

4.1	Source Control BMP

4.1.1	Pollution Prevention

Non-structural and structural source control BMP are required to be incorporated into all new development and significant redevelopment projects. Form 4.1-1 and 4.1-2 are used to describe specific source control BMPs used in the WQMP or to explain why a certain BMP is not applicable. Table 7-3 of the TGD for WQMP provides a list of applicable source control BMP for projects with specific types of potential pollutant sources or activities. The source control BMP in this table must be implemented for projects with these specific types of potential pollutant sources or activities.

The preparers of this WQMP have reviewed the source control BMP requirements for new development and significant redevelopment projects. The preparers have also reviewed the specific BMP required for project as specified in Forms 4.1-1 and 4.1-2. All applicable non-structural and structural source control BMP shall be implemented in the project.

Form 4.1-1 Non-Structural Source Control BMPs
Identifier	Name	Check One	Describe BMP Implementation OR, if not applicable, state reason
Included	Not Applicable
N1	Education of Property Owners, Tenants and Occupants on Stormwater BMPs
N2	Activity Restrictions
N3	Landscape Management BMPs
N4	BMP Maintenance
N5	Title 22 CCR Compliance (How development will comply)
N6	Local Water Quality Ordinances
N7	Spill Contingency Plan
N8	Underground Storage Tank Compliance
N9	Hazardous Materials Disclosure Compliance

Form 4.1-1 Non-Structural Source Control BMPs
Identifier	Name	Check One	Describe BMP Implementation OR, if not applicable, state reason
Included	Not Applicable
N10	Uniform Fire Code Implementation
N11	Litter/Debris Control Program
N12	Employee Training
N13	Housekeeping of Loading Docks
N14	Catch Basin Inspection Program
N15	Vacuum Sweeping of Private Streets and Parking Lots
N16	Other Non-structural Measures for Public Agency Projects
N17	Comply with all other applicable NPDES permits

Form 4.1-2 Structural Source Control BMPs
Identifier	Name	Check One	Describe BMP Implementation OR, If not applicable, state reason
Included	Not Applicable
S1	Provide storm drain system stencilling and signage (CASQA New Development BMP Handbook SD-13)
S2	Design and construct outdoor material storage areas to reduce pollution introduction (CASQA New Development BMP Handbook SD-34)
S3	Design and construct trash and waste storage areas to reduce pollution introduction (CASQA New Development BMP Handbook SD-32)
S4	Use efficient irrigation systems & landscape design, water conservation, smart controllers, and source control (Statewide Model Landscape Ordinance; CASQA New Development BMP Handbook SD-12)
S5	Finish grade of landscaped areas at a minimum of 1-2 inches below top of curb, sidewalk, or pavement
S6	Protect slopes and channels and provide energy dissipation (CASQA New Development BMP Handbook SD-10)
S7	Covered dock areas (CASQA New Development BMP Handbook SD-31)
S8	Covered maintenance bays with spill containment plans (CASQA New Development BMP Handbook SD-31)
S9	Vehicle wash areas with spill containment plans (CASQA New Development BMP Handbook SD-33)
S10	Covered outdoor processing areas (CASQA New Development BMP Handbook SD-36)
Form 4.1-2 Structural Source Control BMPs
Identifier	Name	Check One	Describe BMP Implementation OR, If not applicable, state reason
Included	Not Applicable
S11	Equipment wash areas with spill containment plans (CASQA New Development BMP Handbook SD-33)
S12	Fueling areas (CASQA New Development BMP Handbook SD-30)
S13	Hillside landscaping (CASQA New Development BMP Handbook SD-10)
S14	Wash water control for food preparation areas
S15	Community car wash racks (CASQA New Development BMP Handbook SD-33)

4.1.2	Preventative LID Site Design Practices

Site design practices associated with new LID requirements in the MS4 Permit should be considered in the earliest phases of a project. Preventative site design practices can result in smaller DCV for LID BMP and hydromodification control BMP by reducing runoff generation. Describe site design and drainage plan including:

A narrative of site design practices utilized or rationale for not using practices

A narrative of how site plan incorporates preventive site design practices

Include an attached Site Plan layout which shows how preventative site design practices are included in WQMP

Refer to Section 5.2 of the TGD for WQMP for more details.

Form 4.1-3 Preventative LID Site Design Practices Checklist
Site Design Practices If yes, explain how preventative site design practice is addressed in project site plan. If no, other LID BMPs must be selected to meet targets
Minimize impervious areas: Yes No Explanation:
Maximize natural infiltration capacity: Yes No Explanation:
Preserve existing drainage patterns and time of concentration: Yes No Explanation:
Disconnect impervious areas: Yes No Explanation:
Protect existing vegetation and sensitive areas: Yes No Explanation:
Re-vegetate disturbed areas: Yes No Explanation:
Minimize unnecessary compaction in stormwater retention/infiltration basin/trench areas: Yes No Explanation:
Utilize vegetated drainage swales in place of underground piping or imperviously lined swales: Yes No Explanation:
Stake off areas that will be used for landscaping to minimize compaction during construction : Yes No Explanation:

4.2	Project Performance Criteria

The purpose of this section of the Project WQMP is to establish targets for post-development hydrology based on performance criteria specified in the MS4 Permit. These targets include runoff volume for water quality control (referred to as LID design capture volume), and runoff volume, time of concentration, and peak runoff for protection of any downstream waterbody segments with a HCOC. If the project has more than one outlet for stormwater runoff, then complete additional versions of these forms for each DA / outlet.

Methods applied in the following forms include:

For LID BMP Design Capture Volume (DCV), the San Bernardino County Stormwater Program requires use of the P6 method (MS4 Permit Section XI.D.6a.ii) – Form 4.2-1

For HCOC pre- and post-development hydrologic calculation, the San Bernardino County Stormwater Program requires the use of the Rational Method (San Bernardino County Hydrology Manual Section D). Forms 4.2-2 through Form 4.2-5 calculate hydrologic variables including runoff volume, time of concentration, and peak runoff from the project site pre- and post-development using the Hydrology Manual Rational Method approach. For projects greater than 640 acres (1.0 mi2), the Rational Method and these forms should not be used. For such projects, the Unit Hydrograph Method (San Bernardino County Hydrology Manual Section E) shall be applied for hydrologic calculations for HCOC performance criteria.

Refer to Section 4 in the TGD for WQMP for detailed guidance and instructions.

Form 4.2-1 LID BMP Performance Criteria for Design Capture Volume (DA 1)
1 Project area DA 1 (ft2):	2 Imperviousness after applying preventative site design practices (Imp%):	3 Runoff Coefficient (Rc): _ Rc = 0.858(Imp%)^3-0.78(Imp%)^2+0.774(Imp%)+0.04
4 Determine 1-hour rainfall depth for a 2-year return period P2yr-1hr (in): http://hdsc.nws.noaa.gov/hdsc/pfds/sa/sca_pfds.html
5 Compute P6, Mean 6-hr Precipitation (inches): P6 = Item 4 *C1, where C1 is a function of site climatic region specified in Form 3-1 Item 1 (Valley = 1.4807; Mountain = 1.909; Desert = 1.2371)
6 Drawdown Rate Use 48 hours as the default condition. Selection and use of the 24 hour drawdown time condition is subject to approval by the local jurisdiction. The necessary BMP footprint is a function of drawdown time. While shorter drawdown times reduce the performance criteria for LID BMP design capture volume, the depth of water that can be stored is also reduced.	24-hrs 48-hrs
7 Compute design capture volume, DCV (ft3): DCV = 1/12 * [Item 1* Item 3 *Item 5 * C2], where C2 is a function of drawdown rate (24-hr = 1.582; 48-hr = 1.963) Compute separate DCV for each outlet from the project site per schematic drawn in Form 3-1 Item 2

Form 4.2-2 Summary of HCOC Assessment (DA 1)
Does project have the potential to cause or contribute to an HCOC in a downstream channel: Yes No Go to: http://permitrack.sbcounty.gov/wap/ If “Yes”, then complete HCOC assessment of site hydrology for 2yr storm event using Forms 4.2-3 through 4.2-5 and insert results below (Forms 4.2-3 through 4.2-5 may be replaced by computer software analysis based on the San Bernardino County Hydrology Manual) If “No,” then proceed to Section 4.3 Project Conformance Analysis
Condition	Runoff Volume (ft3)	Time of Concentration (min)	Peak Runoff (cfs)
Pre-developed	1 Form 4.2-3 Item 12	2 Form 4.2-4 Item 13	3 Form 4.2-5 Item 10
Post-developed	4 Form 4.2-3 Item 13	5 Form 4.2-4 Item 14	6 Form 4.2-5 Item 14
Difference	7 Item 4 – Item 1	8 Item 2 – Item 5	9 Item 6 – Item 3
Difference (as % of pre-developed)	10 % Item 7 / Item 1	11 % Item 8 / Item 2	12 % Item 9 / Item 3

Form 4.2-3 HCOC Assessment for Runoff Volume (DA 1)
Weighted Curve Number Determination for: Pre-developed DA	DMA A	DMA B	DMA C	DMA D	DMA E	DMA F	DMA G	DMA H
1a Land Cover type
2a Hydrologic Soil Group (HSG)
3a DMA Area, ft2 sum of areas of DMA should equal area of DA
4a Curve Number (CN) use Items 1 and 2 to select the appropriate CN from Appendix C-2 of the TGD for WQMP
Weighted Curve Number Determination for: Post-developed DA	DMA A	DMA B	DMA C	DMA D	DMA E	DMA F	DMA G	DMA H
1b Land Cover type
2b Hydrologic Soil Group (HSG)
3b DMA Area, ft2 sum of areas of DMA should equal area of DA
4b Curve Number (CN) use Items 5 and 6 to select the appropriate CN from Appendix C-2 of the TGD for WQMP
5 Pre-Developed area-weighted CN:	7 Pre-developed soil storage capacity, S (in): S = (1000 / Item 5) - 10	9 Initial abstraction, Ia (in): Ia = 0.2 * Item 7
6 Post-Developed area-weighted CN:	8 Post-developed soil storage capacity, S (in): S = (1000 / Item 6) - 10	10 Initial abstraction, Ia (in): Ia = 0.2 * Item 8
11 Precipitation for 2 yr, 24 hr storm (in): Go to: http://hdsc.nws.noaa.gov/hdsc/pfds/sa/sca_pfds.html
12 Pre-developed Volume (ft3): Vpre =(1 / 12) * (Item sum of Item 3) * [(Item 11 – Item 9)^2 / ((Item 11 – Item 9 + Item 7)
13 Post-developed Volume (ft3): Vpre =(1 / 12) * (Item sum of Item 3) * [(Item 11 – Item 10)^2 / ((Item 11 – Item 10 + Item 8)
14 Volume Reduction needed to meet HCOC Requirement, (ft3): VHCOC = (Item 13 * 0.95) – Item 12

Form 4.2-4 HCOC Assessment for Time of Concentration (DA 1)
Compute time of concentration for pre and post developed conditions for each DA (For projects using the Hydrology Manual complete the form below)
Variables	Pre-developed DA1 Use additional forms if there are more than 4 DMA	Post-developed DA1 Use additional forms if there are more than 4 DMA
DMA A	DMA B	DMA C	DMA D	DMA A	DMA B	DMA C	DMA D
1 Length of flowpath (ft) Use Form 3-2 Item 5 for pre-developed condition
2 Change in elevation (ft)
3 Slope (ft/ft), So = Item 2 / Item 1
4 Land cover
5 Initial DMA Time of Concentration (min) Appendix C-1 of the TGD for WQMP
6 Length of conveyance from DMA outlet to project site outlet (ft) May be zero if DMA outlet is at project site outlet
7 Cross-sectional area of channel (ft2)
8 Wetted perimeter of channel (ft)
9 Manning’s roughness of channel (n)
10 Channel flow velocity (ft/sec) Vfps = (1.49 / Item 9) * (Item 7/Item 8)^0.67 * (Item 3)^0.5
11 Travel time to outlet (min) Tt = Item 6 / (Item 10 * 60)
12 Total time of concentration (min) Tc = Item 5 + Item 11
13 Pre-developed time of concentration (min): Minimum of Item 12 pre-developed DMA
14 Post-developed time of concentration (min): Minimum of Item 12 post-developed DMA
15 Additional time of concentration needed to meet HCOC requirement (min): TC-HCOC = (Item 13 * 0.95) – Item 14

Form 4.2-5 HCOC Assessment for Peak Runoff (DA 1)
Compute peak runoff for pre- and post-developed conditions
Variables	Pre-developed DA to Project Outlet (Use additional forms if more than 3 DMA)	Post-developed DA to Project Outlet (Use additional forms if more than 3 DMA)
DMA A	DMA B	DMA C	DMA A	DMA B	DMA C
1 Rainfall Intensity for storm duration equal to time of concentration Ipeak = 10^(LOG Form 4.2-1 Item 4 - 0.6 LOG Form 4.2-4 Item 5 /60)
2 Drainage Area of each DMA (Acres) For DMA with outlet at project site outlet, include upstream DMA (Using example schematic in Form 3-1, DMA A will include drainage from DMA C)
3 Ratio of pervious area to total area For DMA with outlet at project site outlet, include upstream DMA (Using example schematic in Form 3-1, DMA A will include drainage from DMA C)
4 Pervious area infiltration rate (in/hr) Use pervious area CN and antecedent moisture condition with Appendix C-3 of the TGD for WQMP
5 Maximum loss rate (in/hr) Fm = Item 3 * Item 4 Use area-weighted Fm from DMA with outlet at project site outlet, include upstream DMA (Using example schematic in Form 3-1, DMA A will include drainage from DMA C)
6 Peak Flow from DMA (cfs) Qp =Item 2 * 0.9 * (Item 1 - Item 5)
7 Time of concentration adjustment factor for other DMA to site discharge point Form 4.2-4 Item 12 DMA / Other DMA upstream of site discharge point (If ratio is greater than 1.0, then use maximum value of 1.0)	DMA A	n/a	n/a
DMA B	n/a	n/a
DMA C	n/a	n/a
8 Pre-developed Qp at Tc for DMA A: Qp = Item 6DMAA + [Item 6DMAB * (Item 1DMAA - Item 5DMAB)/(Item 1DMAB - Item 5DMAB)* Item 7DMAA/2] + [Item 6DMAC * (Item 1DMAA - Item 5DMAC)/(Item 1DMAC - Item 5DMAC)* Item 7DMAA/3]	9 Pre-developed Qp at Tc for DMA B: Qp = Item 6DMAB + [Item 6DMAA * (Item 1DMAB - Item 5DMAA)/(Item 1DMAA - Item 5DMAA)* Item 7DMAB/1] + [Item 6DMAC * (Item 1DMAB - Item 5DMAC)/(Item 1DMAC - Item 5DMAC)* Item 7DMAB/3]	10 Pre-developed Qp at Tc for DMA C: Qp = Item 6DMAC + [Item 6DMAA * (Item 1DMAC - Item 5DMAA)/(Item 1DMAA - Item 5DMAA)* Item 7DMAC/1] + [Item 6DMAB * (Item 1DMAC - Item 5DMAB)/(Item 1DMAB - Item 5DMAB)* Item 7DMAC/2]
10 Peak runoff from pre-developed condition confluence analysis (cfs): Maximum of Item 8, 9, and 10 (including additional forms as needed)
11 Post-developed Qp at Tc for DMA A: Same as Item 8 for post-developed values	12 Post-developed Qp at Tc for DMA B: Same as Item 9 for post-developed values	13 Post-developed Qp at Tc for DMA C: Same as Item 10 for post-developed values
14 Peak runoff from post-developed condition confluence analysis (cfs): Maximum of Item 11, 12, and 13 (including additional forms as needed)
15 Peak runoff reduction needed to meet HCOC Requirement (cfs): Qp-HCOC = (Item 14 * 0.95) – Item 10

4.3	Project Conformance Analysis

Complete the following forms for each project site DA to document that the proposed LID BMPs conform to the project DCV developed to meet performance criteria specified in the MS4 Permit (WQMP Template Section 4.2). For the LID DCV, the forms are ordered according to hierarchy of BMP selection as required by the MS4 Permit (see Section 5.3.1 in the TGD for WQMP). The forms compute the following for on-site LID BMP:

Site Design and Hydrologic Source Controls (Form 4.3-2)

Retention and Infiltration (Form 4.3-3)

Harvested and Use (Form 4.3-4) or

Biotreatment (Form 4.3-5).

At the end of each form, additional fields facilitate the determination of the extent of mitigation provided by the specific BMP category, allowing for use of the next category of BMP in the hierarchy, if necessary.

The first step in the analysis, using Section 5.3.2.1 of the TGD for WQMP, is to complete Forms 4.3-1 and 4.3-3) to determine if retention and infiltration BMPs are infeasible for the project. For each feasibility criterion in Form 4.3-1, if the answer is “Yes,” provide all study findings that includes relevant calculations, maps, data sources, etc. used to make the determination of infeasibility.

Next, complete Forms 4.3-2 and 4.3-4 to determine the feasibility of applicable HSC and harvest and use BMPs, and, if their implementation is feasible, the extent of mitigation of the DCV.

If no site constraints exist that would limit the type of BMP to be implemented in a DA, evaluate the use of combinations of LID BMPs, including all applicable HSC BMPs to maximize on-site retention of the DCV. If no combination of BMP can mitigate the entire DCV, implement the single BMP type, or combination of BMP types, that maximizes on-site retention of the DCV within the minimum effective area.

If the combination of LID HSC, retention and infiltration, and harvest and use BMPs are unable to mitigate the entire DCV, then biotreatment BMPs may be implemented by the project proponent. If biotreatment BMPs are used, then they must be sized to provide sufficient capacity for effective treatment of the remainder of the volume-based performance criteria that cannot be achieved with LID BMPs (TGD for WQMP Section 5.4.4.2). Under no circumstances shall any portion of the DCV be released from the site without effective mitigation and/or treatment.

Form 4.3-1 Infiltration BMP Feasibility (DA 1)
Feasibility Criterion – Complete evaluation for each DA on the Project Site
1 Would infiltration BMP pose significant risk for groundwater related concerns? Yes No Refer to Section 5.3.2.1 of the TGD for WQMP
If Yes, Provide basis: (attach)
2 Would installation of infiltration BMP significantly increase the risk of geotechnical hazards? Yes No (Yes, if the answer to any of the following questions is yes, as established by a geotechnical expert): The location is less than 50 feet away from slopes steeper than 15 percent The location is less than eight feet from building foundations or an alternative setback. A study certified by a geotechnical professional or an available watershed study determines that stormwater infiltration would result in significantly increased risks of geotechnical hazards.
If Yes, Provide basis: (attach)
3 Would infiltration of runoff on a Project site violate downstream water rights? Yes No
If Yes, Provide basis: (attach)
4 Is proposed infiltration facility located on hydrologic soil group (HSG) D soils or does the site geotechnical investigation indicate presence of soil characteristics, which support categorization as D soils? Yes No
If Yes, Provide basis: (attach)
5 Is the design infiltration rate, after accounting for safety factor of 2.0, below proposed facility less than 0.3 in/hr (accounting for soil amendments)? Yes No
If Yes, Provide basis: (attach)
6 Would on-site infiltration or reduction of runoff over pre-developed conditions be partially or fully inconsistent with watershed management strategies as defined in the WAP, or impair beneficial uses? Yes No See Section 3.5 of the TGD for WQMP and WAP
If Yes, Provide basis: (attach)
7 Any answer from Item 1 through Item 3 is “Yes”: Yes No If yes, infiltration of any volume is not feasible onsite. Proceed to Form 4.3-4, Harvest and Use BMP. If no, then proceed to Item 8 below.
8 Any answer from Item 4 through Item 6 is “Yes”: Yes No If yes, infiltration is permissible but is not required to be considered. Proceed to Form 4.3-2, Hydrologic Source Control BMP. If no, then proceed to Item 9, below.
9 All answers to Item 1 through Item 6 are “No”: Infiltration of the full DCV is potentially feasible, LID infiltration BMP must be designed to infiltrate the full DCV to the MEP. Proceed to Form 4.3-2, Hydrologic Source Control BMP.

4.3.1	Site Design Hydrologic Source Control BMP

Section XI.E. of the Permit emphasizes the use of LID preventative measures; and the use of LID HSC BMPs reduces the portion of the DCV that must be addressed in downstream BMPs. Therefore, all applicable HSC shall be provided except where they are mutually exclusive with each other, or with other BMPs. Mutual exclusivity may result from overlapping BMP footprints such that either would be potentially feasible by itself, but both could not be implemented. Please note that while there are no numeric standards regarding the use of HSC, if a project cannot feasibly meet BMP sizing requirements or cannot fully address HCOCs, feasibility of all applicable HSC must be part of demonstrating that the BMP system has been designed to retain the maximum feasible portion of the DCV. Complete Form 4.3-2 to identify and calculate estimated retention volume from implementing site design HSC BMP. Refer to Section 5.4.1 in the TGD for more detailed guidance.

Form 4.3-2 Site Design Hydrologic Source Control BMPs (DA 1)
1 Implementation of Impervious Area Dispersion BMP (i.e. routing runoff from impervious to pervious areas), excluding impervious areas planned for routing to on-lot infiltration BMP: Yes No If yes, complete Items 2-5; If no, proceed to Item 6	DA DMA BMP Type	DA DMA BMP Type	DA DMA BMP Type (Use additional forms for more BMPs)
2 Total impervious area draining to pervious area (ft2)
3 Ratio of pervious area receiving runoff to impervious area
4 Retention volume achieved from impervious area dispersion (ft3) V = Item2 * Item 3 * (0.5/12), assuming retention of 0.5 inches of runoff
5 Sum of retention volume achieved from impervious area dispersion (ft3): Vretention =Sum of Item 4 for all BMPs
6 Implementation of Localized On-lot Infiltration BMPs (e.g. on-lot rain gardens): Yes No If yes, complete Items 7-13 for aggregate of all on-lot infiltration BMP in each DA; If no, proceed to Item 14	DA DMA BMP Type	DA DMA BMP Type	DA DMA BMP Type (Use additional forms for more BMPs)
7 Ponding surface area (ft2)
8 Ponding depth (ft)
9 Surface area of amended soil/gravel (ft2)
10 Average depth of amended soil/gravel (ft)
11 Average porosity of amended soil/gravel
12 Retention volume achieved from on-lot infiltration (ft3) Vretention = (Item 7 *Item 8) + (Item 9 * Item 10 * Item 11)
13 Runoff volume retention from on-lot infiltration (ft3): Vretention =Sum of Item 12 for all BMPs
Form 4.3-2 cont. Site Design Hydrologic Source Control BMPs (DA 1)
14 Implementation of evapotranspiration BMP (green, brown, or blue roofs): Yes No If yes, complete Items 15-20. If no, proceed to Item 21	DA DMA BMP Type	DA DMA BMP Type	DA DMA BMP Type (Use additional forms for more BMPs)
15 Rooftop area planned for ET BMP (ft2)
16 Average wet season ET demand (in/day) Use local values, typical ~ 0.1
17 Daily ET demand (ft3/day) Item 15 * (Item 16 / 12)
18 Drawdown time (hrs) Copy Item 6 in Form 4.2-1
19 Retention Volume (ft3) Vretention = Item 17 * (Item 18 / 24)
20 Runoff volume retention from evapotranspiration BMPs (ft3): Vretention =Sum of Item 19 for all BMPs
21 Implementation of Street Trees: Yes No If yes, complete Items 22-25. If no, proceed to Item 26	DA DMA BMP Type	DA DMA BMP Type	DA DMA BMP Type (Use additional forms for more BMPs)
22 Number of Street Trees
23 Average canopy cover over impervious area (ft2)
24 Runoff volume retention from street trees (ft3) Vretention = Item 22 * Item 23 * (0.05/12) assume runoff retention of 0.05 inches
25 Runoff volume retention from street tree BMPs (ft3): Vretention = Sum of Item 24 for all BMPs
26 Implementation of residential rain barrel/cisterns: Yes No If yes, complete Items 27-29; If no, proceed to Item 30	DA DMA BMP Type	DA DMA BMP Type	DA DMA BMP Type (Use additional forms for more BMPs)
27 Number of rain barrels/cisterns
28 Runoff volume retention from rain barrels/cisterns (ft3) Vretention = Item 27 * 3
29 Runoff volume retention from residential rain barrels/Cisterns (ft3): Vretention =Sum of Item 28 for all BMPs
30 Total Retention Volume from Site Design Hydrologic Source Control BMPs: Sum of Items 5, 13, 20, 25 and 29

4.3.2	Infiltration BMPs

Use Form 4.3-3 to compute on-site retention of runoff from proposed retention and infiltration BMPs. Volume retention estimates are sensitive to the percolation rate used, which determines the amount of runoff that can be infiltrated within the specified drawdown time. The infiltration safety factor reduces field measured percolation to account for potential inaccuracy associated with field measurements, declining BMP performance over time, and compaction during construction. Appendix D of the TGD for WQMP provides guidance on estimating an appropriate safety factor to use in Form 4.3-3.

If site constraints limit the use of BMPs to a single type and implementation of retention and infiltration BMPs mitigate no more than 40% of the DCV, then they are considered infeasible and the Project Proponent may evaluate the effectiveness of BMPs lower in the LID hierarchy of use (Section 5.5.1 of the TGD for WQMP)

If implementation of infiltrations BMPs is feasible as determined using Form 4.3-1, then LID infiltration BMPs shall be implemented to the MEP (section 4.1 of the TGD for WQMP).

.

Form 4.3-3 Infiltration LID BMP - including underground BMPs (DA 1)
1 Remaining LID DCV not met by site design HSC BMP (ft3): Vunmet = Form 4.2-1 Item 7 - Form 4.3-2 Item 30
BMP Type Use columns to the right to compute runoff volume retention from proposed infiltration BMP (select BMP from Table 5-4 in TGD for WQMP) - Use additional forms for more BMPs	DA DMA BMP Type	DA DMA BMP Type	DA DMA BMP Type (Use additional forms for more BMPs)
2 Infiltration rate of underlying soils (in/hr) See Section 5.4.2 and Appendix D of the TGD for WQMP for minimum requirements for assessment methods
3 Infiltration safety factor See TGD Section 5.4.2 and Appendix D
4 Design percolation rate (in/hr) Pdesign = Item 2 / Item 3
5 Ponded water drawdown time (hr) Copy Item 6 in Form 4.2-1
6 Maximum ponding depth (ft) BMP specific, see Table 5-4 of the TGD for WQMP for BMP design details
7 Ponding Depth (ft) dBMP = Minimum of (1/12*Item 4*Item 5) or Item 6
8 Infiltrating surface area, SABMP (ft2) the lesser of the area needed for infiltration of full DCV or minimum space requirements from Table 5.7 of the TGD for WQMP
9 Amended soil depth, dmedia (ft) Only included in certain BMP types, see Table 5-4 in the TGD for WQMP for reference to BMP design details
10 Amended soil porosity
11 Gravel depth, dmedia (ft) Only included in certain BMP types, see Table 5-4 of the TGD for WQMP for BMP design details
12 Gravel porosity
13 Duration of storm as basin is filling (hrs) Typical ~ 3hrs
14 Above Ground Retention Volume (ft3) Vretention = Item 8 * [Item7 + (Item 9 * Item 10) + (Item 11 * Item 12) + (Item 13 * (Item 4 / 12))]
15 Underground Retention Volume (ft3) Volume determined using manufacturer’s specifications and calculations
16 Total Retention Volume from LID Infiltration BMPs: (Sum of Items 14 and 15 for all infiltration BMP included in plan)
17 Fraction of DCV achieved with infiltration BMP: % Retention% = Item 16 / Form 4.2-1 Item 7
18 Is full LID DCV retained onsite with combination of hydrologic source control and LID retention/infiltration BMPs? Yes No If yes, demonstrate conformance using Form 4.3-10; If no, then reduce Item 3, Factor of Safety to 2.0 and increase Item 8, Infiltrating Surface Area, such that the portion of the site area used for retention and infiltration BMPs equals or exceeds the minimum effective area thresholds (Table 5-7 of the TGD for WQMP) for the applicable category of development and repeat all above calculations.

4.3.3	Harvest and Use BMP

Harvest and use BMP may be considered if the full LID DCV cannot be met by maximizing infiltration BMPs. Use Form 4.3-4 to compute on-site retention of runoff from proposed harvest and use BMPs.

Volume retention estimates for harvest and use BMPs are sensitive to the on-site demand for captured stormwater. Since irrigation water demand is low in the wet season, when most rainfall events occur in San Bernardino County, the volume of water that can be used within a specified drawdown period is relatively low. The bottom portion of Form 4.3-4 facilitates the necessary computations to show infeasibility if a minimum incremental benefit of 40 percent of the LID DCV would not be achievable with MEP implementation of on-site harvest and use of stormwater (Section 5.5.4 of the TGD for WQMP).

Form 4.3-4 Harvest and Use BMPs (DA 1)
1 Remaining LID DCV not met by site design HSC or infiltration BMP (ft3): Vunmet = Form 4.2-1 Item 7 - Form 4.3-2 Item 30 – Form 4.3-3 Item 16
BMP Type(s) Compute runoff volume retention from proposed harvest and use BMP (Select BMPs from Table 5-4 of the TGD for WQMP) - Use additional forms for more BMPs	DA DMA BMP Type	DA DMA BMP Type	DA DMA BMP Type (Use additional forms for more BMPs)
2 Describe cistern or runoff detention facility
3 Storage volume for proposed detention type (ft3) Volume of cistern
4 Landscaped area planned for use of harvested stormwater (ft2)
5 Average wet season daily irrigation demand (in/day) Use local values, typical ~ 0.1 in/day
6 Daily water demand (ft3/day) Item 4 * (Item 5 / 12)
7 Drawdown time (hrs) Copy Item 6 from Form 4.2-1
8Retention Volume (ft3) Vretention = Minimum of (Item 3) or (Item 6 * (Item 7 / 24))
9 Total Retention Volume (ft3) from Harvest and Use BMP Sum of Item 8 for all harvest and use BMP included in plan
10 Is the full DCV retained with a combination of LID HSC, retention and infiltration, and harvest & use BMPs? Yes No If yes, demonstrate conformance using Form 4.3-10. If no, then re-evaluate combinations of all LID BMP and optimize their implementation such that the maximum portion of the DCV is retained on-site (using a single BMP type or combination of BMP types). If the full DCV cannot be mitigated after this optimization process, proceed to Section 4.3.4.

4.3.4	Biotreatment BMP

Biotreatment BMPs may be considered if the full LID DCV cannot be met by maximizing retention and infiltration, and harvest and use BMPs. A key consideration when using biotreatment BMP is the effectiveness of the proposed BMP in addressing the pollutants of concern for the project (see Table 5-5 of the TGD for WQMP).

Use Form 4.3-5 to summarize the potential for volume based and/or flow based biotreatment options to biotreat the remaining unmet LID DCV w. Biotreatment computations are included as follows:

Use Form 4.3-6 to compute biotreatment in small volume based biotreatment BMP (e.g. bioretention w/underdrains);

Use Form 4.3-7 to compute biotreatment in large volume based biotreatment BMP (e.g. constructed wetlands);

Form 4.3-5 Selection and Evaluation of Biotreatment BMP (DA 1)
1 Remaining LID DCV not met by site design HSC, infiltration, or harvest and use BMP for potential biotreatment (ft3): Form 4.2-1 Item 7 - Form 4.3-2 Item 30 – Form 4.3-3 Item 16- Form 4.3-4 Item 9	List pollutants of concern Copy from Form 2.3-1.
2 Biotreatment BMP Selected (Select biotreatment BMP(s) necessary to ensure all pollutants of concern are addressed through Unit Operations and Processes, described in Table 5-5 of the TGD for WQMP)	Volume-based biotreatment Use Forms 4.3-6 and 4.3-7 to compute treated volume	Flow-based biotreatment Use Form 4.3-8 to compute treated volume
Bioretention with underdrain Planter box with underdrain Constructed wetlands Wet extended detention Dry extended detention	Vegetated swale Vegetated filter strip Proprietary biotreatment
3 Volume biotreated in volume based biotreatment BMP (ft3): Form 4.3-6 Item 15 + Form 4.3-7 Item 13	4 Compute remaining LID DCV with implementation of volume based biotreatment BMP (ft3): Item 1 – Item 3	5 Remaining fraction of LID DCV for sizing flow based biotreatment BMP: % Item 4 / Item 1
6 Flow-based biotreatment BMP capacity provided (cfs): Use Figure 5-2 of the TGD for WQMP to determine flow capacity required to provide biotreatment of remaining percentage of unmet LID DCV (Item 5), for the project’s precipitation zone (Form 3-1 Item 1)
7 Metrics for MEP determination: Provided a WQMP with the portion of site area used for suite of LID BMP equal to minimum thresholds in Table 5-7 of the TGD for WQMP for the proposed category of development: If maximized on-site retention BMPs is feasible for partial capture, then LID BMP implementation must be optimized to retain and infiltrate the maximum portion of the DCV possible within the prescribed minimum effective area. The remaining portion of the DCV shall then be mitigated using biotreatment BMP.

Use Form 4.3-8 to compute sizing criteria for flow-based biotreatment BMP (e.g. bioswales)

Form 4.3-6 Volume Based Biotreatment (DA 1) – Bioretention and Planter Boxes with Underdrains
Biotreatment BMP Type (Bioretention w/underdrain, planter box w/underdrain, other comparable BMP)	DA DMA BMP Type	DA DMA BMP Type	DA DMA BMP Type (Use additional forms for more BMPs)
1 Pollutants addressed with BMP List all pollutant of concern that will be effectively reduced through specific Unit Operations and Processes described in Table 5-5 of the TGD for WQMP
2 Amended soil infiltration rate Typical ~ 5.0
3 Amended soil infiltration safety factor Typical ~ 2.0
4 Amended soil design percolation rate (in/hr) Pdesign = Item 2 / Item 3
5 Ponded water drawdown time (hr) Copy Item 6 from Form 4.2-1
6 Maximum ponding depth (ft) see Table 5-6 of the TGD for WQMP for reference to BMP design details
7 Ponding Depth (ft) dBMP = Minimum of (1/12 * Item 4 * Item 5) or Item 6
8 Amended soil surface area (ft2)
9 Amended soil depth (ft) see Table 5-6 of the TGD for WQMP for reference to BMP design details
10 Amended soil porosity, n
11 Gravel depth (ft) see Table 5-6 of the TGD for WQMP for reference to BMP design details
12 Gravel porosity, n
13 Duration of storm as basin is filling (hrs) Typical ~ 3hrs
14 Biotreated Volume (ft3) Vbiotreated = Item 8 * [(Item 7/2) + (Item 9 * Item 10) +(Item 11 * Item 12) + (Item 13 * (Item 4 / 12))]
15 Total biotreated volume from bioretention and/or planter box with underdrains BMP: Sum of Item 14 for all volume-based BMPs included in this form

Form 4.3-7 Volume Based Biotreatment (DA 1) – Constructed Wetlands and Extended Detention
Biotreatment BMP Type Constructed wetlands, extended wet detention, extended dry detention, or other comparable proprietary BMP. If BMP includes multiple modules (e.g. forebay and main basin), provide separate estimates for storage and pollutants treated in each module.	DA DMA BMP Type	DA DMA BMP Type (Use additional forms for more BMPs)
Forebay	Basin	Forebay	Basin
1 Pollutants addressed with BMP forebay and basin List all pollutant of concern that will be effectively reduced through specific Unit Operations and Processes described in Table 5-5 of the TGD for WQMP
2 Bottom width (ft)
3 Bottom length (ft)
4 Bottom area (ft2) Abottom = Item 2 * Item 3
5 Side slope (ft/ft)
6 Depth of storage (ft)
7 Water surface area (ft2) Asurface =(Item 2 + (2 * Item 5 * Item 6)) * (Item 3 + (2 * Item 5 * Item 6))
8 Storage volume (ft3) For BMP with a forebay, ensure fraction of total storage is within ranges specified in BMP specific fact sheets, see Table 5-6 of the TGD for WQMP for reference to BMP design details V =Item 6 / 3 * [Item 4 + Item 7 + (Item 4 * Item 7)^0.5]
9 Drawdown Time (hrs) Copy Item 6 from Form 2.1
10 Outflow rate (cfs) QBMP = (Item 8forebay + Item 8basin) / (Item 9 * 3600)
11 Duration of design storm event (hrs)
12 Biotreated Volume (ft3) Vbiotreated = (Item 8forebay + Item 8basin) +( Item 10 * Item 11 * 3600)
13 Total biotreated volume from constructed wetlands, extended dry detention, or extended wet detention : (Sum of Item 12 for all BMP included in plan)

Form 4.3-8 Flow Based Biotreatment (DA 1)
Biotreatment BMP Type Vegetated swale, vegetated filter strip, or other comparable proprietary BMP	DA DMA BMP Type	DA DMA BMP Type	DA DMA BMP Type (Use additional forms for more BMPs)
1 Pollutants addressed with BMP List all pollutant of concern that will be effectively reduced through specific Unit Operations and Processes described in TGD Table 5-5
2 Flow depth for water quality treatment (ft) BMP specific, see Table 5-6 of the TGD for WQMP for reference to BMP design details
3 Bed slope (ft/ft) BMP specific, see Table 5-6 of the TGD for WQMP for reference to BMP design details
4 Manning's roughness coefficient
5 Bottom width (ft) bw = (Form 4.3-5 Item 6 * Item 4) / (1.49 * Item 2^1.67 * Item 3^0.5)
6 Side Slope (ft/ft) BMP specific, see Table 5-6 of the TGD for WQMP for reference to BMP design details
7 Cross sectional area (ft2) A = (Item 5 * Item 2) + (Item 6 * Item 2^2)
8 Water quality flow velocity (ft/sec) V = Form 4.3-5 Item 6 / Item 7
9 Hydraulic residence time (min) Pollutant specific, see Table 5-6 of the TGD for WQMP for reference to BMP design details
10 Length of flow based BMP (ft) L = Item 8 * Item 9 * 60
11 Water surface area at water quality flow depth (ft2) SAtop = (Item 5 + (2 * Item 2 * Item 6)) * Item 10

4.3.5	Conformance Summary

Complete Form 4.3-9 to demonstrate how on-site LID DCV is met with proposed site design hydrologic source control, infiltration, harvest and use, and/or biotreatment BMP. The bottom line of the form is used to describe the basis for infeasibility determination for on-site LID BMP to achieve full LID DCV, and provides methods for computing remaining volume to be addressed in an alternative compliance plan. If the project has more than one outlet, then complete additional versions of this form for each outlet.

Form 4.3-9 Conformance Summary and Alternative Compliance Volume Estimate (DA 1)
1 Total LID DCV for the Project DA-1 (ft3): Copy Item 7 in Form 4.2-1
2 On-site retention with site design hydrologic source control LID BMP (ft3): Copy Item 30 in Form 4.3-2
3 On-site retention with LID infiltration BMP (ft3): Copy Item 16 in Form 4.3-3
4 On-site retention with LID harvest and use BMP (ft3): Copy Item 9 in Form 4.3-4
5 On-site biotreatment with volume based biotreatment BMP (ft3): Copy Item 3 in Form 4.3-5
6 Flow capacity provided by flow based biotreatment BMP (cfs): Copy Item 6 in Form 4.3-5
7 LID BMP performance criteria are achieved if answer to any of the following is “Yes”: Full retention of LID DCV with site design HSC, infiltration, or harvest and use BMP: Yes No If yes, sum of Items 2, 3, and 4 is greater than Item 1 Combination of on-site retention BMPs for a portion of the LID DCV and volume-based biotreatment BMP that address all pollutants of concern for the remaining LID DCV: Yes No If yes, a) sum of Items 2, 3, 4, and 5 is greater than Item 1, and Items 2, 3 and 4 are maximized; or b) Item 6 is greater than Form 4.35 Item 6 and Items 2, 3 and 4 are maximized On-site retention and infiltration is determined to be infeasible and biotreatment BMP provide biotreatment for all pollutants of concern for full LID DCV: Yes No If yes, Form 4.3-1 Items 7 and 8 were both checked yes
8 If the LID DCV is not achieved by any of these means, then the project may be allowed to develop an alternative compliance plan. Check box that describes the scenario which caused the need for alternative compliance: Combination of HSC, retention and infiltration, harvest and use, and biotreatment BMPs provide less than full LID DCV capture: Checked yes for Form 4.3-5 Item 7, Item 6 is zero, and sum of Items 2, 3, 4, and 5 is less than Item 1. If so, apply water quality credits and calculate volume for alternative compliance, Valt = (Item 1 – Item 2 – Item 3 – Item 4 – Item 5) * (100 - Form 2.4-1 Item 2)% An approved Watershed Action Plan (WAP) demonstrates that water quality and hydrologic impacts of urbanization are more effective when managed in at an off-site facility: Attach appropriate WAP section, including technical documentation, showing effectiveness comparisons for the project site and regional watershed

4.3.6	Hydromodification Control BMP

Use Form 4.3-10 to compute the remaining runoff volume retention, after LID BMP are implemented, needed to address HCOC, and the increase in time of concentration and decrease in peak runoff necessary to meet targets for protection of waterbodies with a potential HCOC. Describe hydromodification control BMP that address HCOC, which may include off-site BMP and/or in-stream controls. Section 5.6 of the TGD for WQMP provides additional details on selection and evaluation of hydromodification control BMP.

Form 4.3-10 Hydromodification Control BMPs (DA 1)
1 Volume reduction needed for HCOC performance criteria (ft3): (Form 4.2-2 Item 4 * 0.95) – Form 4.2-2 Item 1	2 On-site retention with site design hydrologic source control, infiltration, and harvest and use LID BMP (ft3): Sum of Form 4.3-9 Items 2, 3, and 4 Evaluate option to increase implementation of on-site retention in Forms 4.3-2, 4.3-3, and 4.3-4 in excess of LID DCV toward achieving HCOC volume reduction
3 Remaining volume for HCOC volume capture (ft3): Item 1 – Item 2	4 Volume capture provided by incorporating additional on-site or off-site retention BMPs (ft3): Existing downstream BMP may be used to demonstrate additional volume capture (if so, attach to this WQMP a hydrologic analysis showing how the additional volume would be retained during a 2-yr storm event for the regional watershed)
5 If Item 4 is less than Item 3, incorporate in-stream controls on downstream waterbody segment to prevent impacts due to hydromodification Attach in-stream control BMP selection and evaluation to this WQMP
6 Is Form 4.2-2 Item 11 less than or equal to 5%: Yes No If yes, HCOC performance criteria is achieved. If no, select one or more mitigation options below: Demonstrate increase in time of concentration achieved by proposed LID site design, LID BMP, and additional on-site or off-site retention BMP BMP upstream of a waterbody segment with a potential HCOC may be used to demonstrate increased time of concentration through hydrograph attenuation (if so, show that the hydraulic residence time provided in BMP for a 2-year storm event is equal or greater than the addition time of concentration requirement in Form 4.2-4 Item 15) Increase time of concentration by preserving pre-developed flow path and/or increase travel time by reducing slope and increasing cross-sectional area and roughness for proposed on-site conveyance facilities Incorporate appropriate in-stream controls for downstream waterbody segment to prevent impacts due to hydromodification, in a plan approved and signed by a licensed engineer in the State of California
7 Form 4.2-2 Item 12 less than or equal to 5%: Yes No If yes, HCOC performance criteria is achieved. If no, select one or more mitigation options below: Demonstrate reduction in peak runoff achieved by proposed LID site design, LID BMPs, and additional on-site or off-site retention BMPs BMPs upstream of a waterbody segment with a potential HCOC may be used to demonstrate additional peak runoff reduction through hydrograph attenuation (if so, attach to this WQMP, a hydrograph analysis showing how the peak runoff would be reduced during a 2-yr storm event) Incorporate appropriate in-stream controls for downstream waterbody segment to prevent impacts due to hydromodification, in a plan approved and signed by a licensed engineer in the State of California

4.4	Alternative Compliance Plan (if applicable)

Describe an alternative compliance plan (if applicable) for projects not fully able to infiltrate, harvest and use, or biotreat the DCV via on-site LID practices. A project proponent must develop an alternative compliance plan to address the remainder of the LID DCV. Depending on project type some projects may qualify for water quality credits that can be applied to reduce the DCV that must be treated prior to development of an alternative compliance plan (see Form 2.4-1, Water Quality Credits). Form 4.3-9 Item 8 includes instructions on how to apply water quality credits when computing the DCV that must be met through alternative compliance. Alternative compliance plans may include one or more of the following elements:

On-site structural treatment control BMP - All treatment control BMP should be located as close to possible to the pollutant sources and should not be located within receiving waters;

Off-site structural treatment control BMP - Pollutant removal should occur prior to discharge of runoff to receiving waters;

Urban runoff fund or In-lieu program, if available

Depending upon the proposed alternative compliance plan, approval by the executive officer may or may not be required (see Section 6 of the TGD for WQMP).

Section 5	Inspection and Maintenance Responsibility
for Post Construction BMP

All BMP included as part of the project WQMP are required to be maintained through regular scheduled inspection and maintenance (refer to Section 8, Post Construction BMP Requirements, in the TGD for WQMP). Fully complete Form 5-1 summarizing all BMP included in the WQMP. Attach additional forms as needed. The WQMP shall also include a detailed Operation and Maintenance Plan for all BMP and may require a Maintenance Agreement (consult the jurisdiction’s LIP). If a Maintenance Agreement is required, it must also be attached to the WQMP.

Form 5-1 BMP Inspection and Maintenance (use additional forms as necessary)
BMP	Reponsible Party(s)	Inspection/ Maintenance Activities Required	Minimum Frequency of Activities

Section 6	WQMP Attachments

6.1.	Site Plan and Drainage Plan

Include a site plan and drainage plan sheet set containing the following minimum information:

Project location

Site boundary

Land uses and land covers, as applicable

Suitability/feasibility constraints

Structural Source Control BMP locations

Site Design Hydrologic Source Control BMP locations

LID BMP details

Drainage delineations and flow information

Drainage connections

6.2	Electronic Data Submittal

Minimum requirements include submittal of PDF exhibits in addition to hard copies. Format must not require specialized software to open. If the local jurisdiction requires specialized electronic document formats (as described in their local Local Implementation Plan), this section will describe the contents (e.g., layering, nomenclature, geo-referencing, etc.) of these documents so that they may be interpreted efficiently and accurately.

6.3	Post Construction

Attach all O&M Plans and Maintenance Agreements for BMP to the WQMP.

6.4	Other Supporting Documentation

BMP Educational Materials

Activity Restriction – C, C&R’s & Lease Agreements