- 1 -
Project Specific Water Quality Management Plan
A Template for Projects located within the Santa Ana Watershed Region of Riverside County
Project Title: TRACT 38921
Development No: P24-XXXX
Design Review/Case No: DP-2023-01293
Original Date Prepared
: February 22, 2024
Revision Date(s): Insert text here
Prepared for Compliance with
Regional Board Order No. R8-2010-0033
Template revised June 30, 2016
Contact Information:
Prepared for:
La Sierra Victoria Development LLC
19215 Wild Mustang Court
Apple Valley, CA 92307
Prepared by:
6879 AIRPORT DRIVE
RIVERSIDE, CA, 92504
TEL: 951.688.0241
EMAIL: [email protected]
Michael R. Brendecke
Preliminary
Final
PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies - 2 -
OWNER’S CERTIFICATION
This Project-Specific Water Quality Management Plan (WQMP) has been prepared for La Sierra Victoria Development LLC by Adkan Engineers for the Tract 38921, located on southeast corner of Victoria Avenue and La Sierra Avenue.
This WQMP is intended to comply with the requirements of City of Riverside for Tentative tract map. Planning Case No. DP-2023-01293 which includes the requirement for the preparation and implementation of a Project-Specific WQMP.
The undersigned, while owning the property/project described in the preceding paragraph, shall be responsible for the implementation and funding of this WQMP and will ensure that this WQMP is amended as appropriate to reflect up-to-date conditions on the site. In addition, the property owner accepts responsibility for interim operation and maintenance of Stormwater BMPs until such time as this responsibility is formally transferred to a subsequent owner. This WQMP will be reviewed with the facility operator, facility supervisors, employees, tenants, maintenance and service contractors, or any other party (or parties) having responsibility for implementing portions of this WQMP. At least one copy of this WQMP will be maintained at the project site or project office in perpetuity. The undersigned is authorized to certify and to approve implementation of this WQMP. The undersigned is aware that implementation of this WQMP is enforceable under
city of riverside Water Quality Ordinance (Municipal Code Section 14.12.315).
"I, the undersigned, certify under penalty of law that the provisions of this WQMP have been reviewed and accepted and that the WQMP will be transferred to future successors in interest."
Owner’s Signature Date
Owner’s Printed Name Owner’s Title/Position
PREPARER’S CERTIFICATION
“The selection, sizing and design of stormwater treatment and other stormwater quality and quantity control measures in this plan meet the requirements of Regional Water Quality Control Board Order No. R8-2010-0033 and any subsequent amendments thereto.”
Preparer’s Signature Date
Michael Brendecke Senior Project Manager
Preparer’s Printed Name Preparer’s Title/Position
Preparer’s Licensure:
PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies - 3 -
Table of Contents
Section A: Project and Site Information........................................................................................................ 6 A.1 Maps and Site Plans ............................................................................................................................ 6 A.2 Identify Receiving Waters ................................................................................................................... 7 A.3 Additional Permits/Approvals required for the Project: .................................................................... 7 Section B: Optimize Site Utilization (LID Principles) ..................................................................................... 8 Section C: Delineate Drainage Management Areas (DMAs) ......................................................................... 9 Section D: Implement LID BMPs ................................................................................................................. 11 D.1 Infiltration Applicability .................................................................................................................... 11 D.2 Harvest and Use Assessment ............................................................................................................ 12 D.3 Bioretention and Biotreatment Assessment .................................................................................... 14 D.4 Feasibility Assessment Summaries ................................................................................................... 15 D.5 LID BMP Sizing .................................................................................................................................. 16 Section E: Alternative Compliance (LID Waiver Program) .......................................................................... 17 E.1 Identify Pollutants of Concern .......................................................................................................... 18 E.2 Stormwater Credits ........................................................................................................................... 19 E.3 Sizing Criteria ..................................................................................................................................... 19 E.4 Treatment Control BMP Selection .................................................................................................... 20 Section F: Hydromodification ..................................................................................................................... 21 F.1 Hydrologic Conditions of Concern (HCOC) Analysis .......................................................................... 21 F.2 HCOC Mitigation ................................................................................................................................ 22 Section G: Source Control BMPs ................................................................................................................. 23 Section H: Construction Plan Checklist ....................................................................................................... 25 Section I: Operation, Maintenance and Funding ........................................................................................ 26
PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies - 4 -
List of Tables
Table A.1 Identification of Receiving Waters ................................................................................................ 7 Table A.2 Other Applicable Permits .............................................................................................................. 7 Table C.1 DMA Classifications ....................................................................................................................... 9 Table C.2 Type ‘A’, Self-Treating Areas ......................................................................................................... 9 Table C.3 Type ‘B’, Self-Retaining Areas ....................................................................................................... 9 Table C.4 Type ‘C’, Areas that Drain to Self-Retaining Areas ...................................................................... 10 Table C.5 Type ‘D’, Areas Draining to BMPs ............................................................................................... 10 Table D.1 Infiltration Feasibility .................................................................................................................. 11 Table D.2 LID Prioritization Summary Matrix ............................................................................................. 15 Table D.3 DCV Calculations for LID BMPs ................................................................................................... 16 Table E.1 Potential Pollutants by Land Use Type ........................................................................................ 18 Table E.2 Water Quality Credits .................................................................................................................. 19 Table E.3 Treatment Control BMP Sizing .................................................................................................... 19 Table E.4 Treatment Control BMP Selection .............................................................................................. 20 Table F.1 Hydrologic Conditions of Concern Summary .............................................................................. 21 Table G.1 Permanent and Operational Source Control Measures ............................................................. 24 Table H.1 Construction Plan Cross-reference ............................................................................................. 25
List of Appendices
Appendix 1: Maps and Site Plans ................................................................................................................ 27 Appendix 2: Construction Plans .................................................................................................................. 28 Appendix 3: Soils Information ..................................................................................................................... 29 Appendix 4: Historical Site Conditions ........................................................................................................ 30 Appendix 5: LID Infeasibility ........................................................................................................................ 31 Appendix 6: BMP Design Details ................................................................................................................. 32 Appendix 7: Hydromodification .................................................................................................................. 33 Appendix 8: Source Control ........................................................................................................................ 34 Appendix 9: O&M ....................................................................................................................................... 35 Appendix 10: Educational Materials ....................................................................................................... - 36 -
PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies - 6 -
Section A: Project and Site Information
PROJECT INFORMATION
Type of Project: Residential
Planning Area: La Sierra South
Community Name: La Sierra South
Development Name: TRACT 38921
PROJECT LOCATION
Latitude & Longitude (DMS): 33°88’76”N 117°27’43”W
Project Watershed and Sub-Watershed: Prado Basin/Temescal Creek, Reach 1 Gross Acres: 10.8
APN(s): 136-220-016
Map Book and Page No.: Thomas Guide 2008 Edition, Page 744, Grid G-3
PROJECT CHARACTERISTICS
Proposed or Potential Land Use(s) Residential
Proposed or Potential SIC Code(s) 1521
Area of Impervious Project Footprint (SF) 341,993
Total Area of proposed Impervious Surfaces within the Project Footprint (SF)/or Replacement 341,993 Does the project consist of offsite road improvements? Y N Does the project propose to construct unpaved roads? Y N Is the project part of a larger common plan of development (phased project)? Y N
EXISTING SITE CHARACTERISTICS
Total area of existing Impervious Surfaces within the Project limits Footprint (SF) 4943 Is the project located within any MSHCP Criteria Cell? Y N If so, identify the Cell number:
Are there any natural hydrologic features on the project site? Y N Is a Geotechnical Report attached? Y N
If no Geotech. Report, list the NRCS soils type(s) present on the site (A, B, C and/or D) What is the Water Quality Design Storm Depth for the project? 0.56 in
A.1 Maps and Site Plans
When completing your Project-Specific WQMP, include a map of the local vicinity and existing site. In addition, include all grading, drainage, landscape/plant palette and other pertinent construction plans in Appendix 2. At a minimum, your WQMP Site Plan should include the following:
• Drainage Management Areas
• Proposed Structural BMPs
• Drainage Path
• Drainage Infrastructure, Inlets, Overflows
• Source Control BMPs
• Buildings, Roof Lines, Downspouts
• Impervious Surfaces
• Standard Labeling
• BMP Locations (Lat/Long)
PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies - 7 -
A.2 Identify Receiving Waters
Using Table A.1 below, list in order of upstream to downstream, the receiving waters that the project site is tributary to. Continue to fill each row with the Receiving Water’s 303(d) listed impairments (if any), designated beneficial uses, and proximity, if any, to a RARE beneficial use. Include a map of the receiving waters in Appendix 1.
Table A.1 Identification of Receiving Waters
Receiving Waters EPA Approved 303(d) List
Impairments
Designated
Beneficial Uses
Proximity to RARE
Beneficial Use
Arizona Channel 8.8 mi
Arlington Channel 7.5 mi
Temescal Creek, Reach 1 pH REC1. REC2. WARM, WILD 2.7 mi Prado Creek Basin Nutrients, Pathogens, TSS REC1. REC2. WARM, WILD, RARE
A.3 Additional Permits/Approvals required for the Project:
Table A.2 Other Applicable Permits
Agency Permit Required
State Department of Fish and Game, 1602 Streambed Alteration Agreement Y N State Water Resources Control Board, Clean Water Act (CWA) Section 401 Water Quality Cert. Y N US Army Corps of Engineers, CWA Section 404 Permit Y N US Fish and Wildlife, Endangered Species Act Section 7 Biological Opinion Y N Statewide Construction General Permit Coverage Y N
Statewide Industrial General Permit Coverage Y N
Western Riverside MSHCP Consistency Approval (e.g., JPR, DBESP) Y N Other (please list in the space below as required)
City of Riverside Building permit
City of Riverside Grading permit
City of Riverside Construction Permit
Y N
If yes is answered to any of the questions above, the Co-Permittee may require proof of approval/coverage from those agencies as applicable including documentation of any associated requirements that may affect this Project-Specific WQMP.
PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies - 8 -
Section B: Optimize Site Utilization (LID Principles)
Site Optimization
Did you identify and preserve existing drainage patterns? If so, how? If not, why? Yes, the grading design preserves the historic drainage patterns north to Victoria Avenue.
Did you identify and protect existing vegetation? If so, how? If not, why? Some, where possible. The project site is currently orange groves which will need to be removed in order to develop the site. The orange groves will be preserved at the northerly edge of site along Victoria Ave up to 100’ from the edge of roadway in accordance with the Victoria Ave policy.
Did you identify and preserve natural infiltration capacity? If so, how? If not, why? Natural infiltration capacity was preserved with the implementation of an onsite infiltration basin.
Did you identify and minimize impervious area? If so, how? If not, why? Impervious areas were minimized to the maximum extent practicable. Landscaping is being incorporated into the site in all feasible areas.
Did you identify and disperse runoff to adjacent pervious areas? If so, how? If not, why? Onsite drainage will be conveyed to a proposed infiltration basin at the north east corner of the site via surface drainage and a storm drain system.
PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies - 9 -
Section C: Delineate Drainage Management Areas
(DMAs)
Utilizing the procedure in Section 3.3 of the WQMP Guidance Document which discusses the methods of delineating and mapping your project site into individual DMAs, complete Table C.1 below to appropriately categorize the types of classification (e.g., Type A, Type B, etc.) per DMA for your project site. Upon completion of this table, this information will then be used to populate and tabulate the corresponding tables for their respective DMA classifications.
Table C.1 DMA Classifications
DMA Name or ID Surface Type(s)12 Area (Sq. Ft.) DMA Type C1 Roofs 132,538 C
C2 Streets 65,141 C
C3 Landscaping 111,239 C
B1 Natural A Soil (infiltration
basin)
3,674 B
1Reference Table 2-1 in the WQMP Guidance Document to populate this column 2If multi-surface provide back-up
Table C.2 Type ‘A’, Self-Treating Areas
DMA Name or ID Area (Sq. Ft.) Stabilization Type Irrigation Type (if any) A1 29,400 Existing orange groves
Table C.3 Type ‘B’, Self-Retaining Areas
Self-Retaining Area
Type ‘C’ DMAs that are draining to the Self- Retaining
Area
DMA
Name/ ID
Post-project
surface type
Area
(square
feet)
Storm
Depth
(inches) DMA Name /
ID
[C] from Table C.4 =
Required Retention Depth
(inches)
[A] [B] [C] [D]
B1
Natural A Soil
(infiltration
basin)
3674 0.56 C1 132538 11.3
C2 65141 5.6
C3 11123.9 0.9
PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies - 10 -
= +
∙
Table C.4 Type ‘C’, Areas that Drain to Self-Retaining Areas DMA Receiving Self-Retaining DMA
DMA Name/ ID
Area
(square feet)
Post-project
surface type
Impervious
fraction
Product
DMA name /ID
Area (square
feet) Ratio
[A] [B] [C] = [A] x [B] [D] [C]/[D]
C1 132538 Roofs 1.00 132538 B1 3674 36.07
C2 65141 Concrete/Asphalt1.00 65141 B1 3674 17.73
C3 11139 Ornamental
Landscaping
0.10 11123.9 B1 3674 3.03
Table C.5 Type ‘D’, Areas Draining to BMPs
DMA Name or ID BMP Name or ID
Note: More than one drainage management area can drain to a single LID BMP, however, one drainage management area may not drain to more than one BMP.
PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies - 11 -
Section D: Implement LID BMPs
D.1 Infiltration Applicability
Is there an approved downstream ‘Highest and Best Use’ for stormwater runoff (see discussion in Chapter
2.4.4 of the WQMP Guidance Document for further details)? Y N If yes has been checked, Infiltration BMPs shall not be used for the site; proceed to section D.3 If no, continue working through this section to implement your LID BMPs. It is recommended that you contact your Co-Permittee to verify whether or not your project discharges to an approved downstream ‘Highest and Best Use’ feature.
Geotechnical Report
A Geotechnical Report or Phase I Environmental Site Assessment may be required by the Copermittee to confirm present and past site characteristics that may affect the use of Infiltration BMPs. In addition, the Co-Permittee, at their discretion, may not require a geotechnical report for small projects as described in Chapter 2 of the WQMP Guidance Document. If a geotechnical report has been prepared, include it in Appendix 3. In addition, if a Phase I Environmental Site Assessment has been prepared, include it in Appendix 4.
Is this project classified as a small project consistent with the requirements of Chapter 2 of the WQMP Guidance Document?
Y N
Infiltration Feasibility
Table D.1 below is meant to provide a simple means of assessing which DMAs on your site support Infiltration BMPs and is discussed in the WQMP Guidance Document in Chapter 2.4.5. Check the appropriate box for each question and then list affected DMAs as applicable. If additional space is needed, add a row below the corresponding answer.
Table D.1 Infiltration Feasibility
Does the project site… YES NO
…have any DMAs with a seasonal high groundwater mark shallower than 10 feet? X If Yes, list affected DMAs:
…have any DMAs located within 100 feet of a water supply well? X If Yes, list affected DMAs:
…have any areas identified by the geotechnical report as posing a public safety risk where infiltration of stormwater could have a negative impact?
X
If Yes, list affected DMAs:
…have measured in-situ infiltration rates of less than 1.6 inches / hour? X If Yes, list affected DMAs:
…have significant cut and/or fill conditions that would preclude in-situ testing of infiltration rates at the final infiltration surface?
X
If Yes, list affected DMAs:
…geotechnical report identify other site-specific factors that would preclude effective and safe infiltration? X Describe here:
If you answered “Yes” to any of the questions above for any DMA, Infiltration BMPs should not be used for those DMAs and you should proceed to the assessment for Harvest and Use below.
PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies - 12 -
D.2 Harvest and Use Assessment
Please check what applies:
☐ Reclaimed water will be used for the non-potable water demands for the project. ☐Downstream water rights may be impacted by Harvest and Use as approved by the Regional Board (verify with the Copermittee).
☐The Design Capture Volume will be addressed using Infiltration Only BMPs. In such a case, Harvest and Use BMPs are still encouraged, but it would not be required if the Design Capture Volume will be infiltrated or evapotranspired.
If any of the above boxes have been checked, Harvest and Use BMPs need not be assessed for the site. If none of the above criteria applies, follow the steps below to assess the feasibility of irrigation use, toilet use and other non-potable uses (e.g., industrial use).
Irrigation Use Feasibility
Complete the following steps to determine the feasibility of harvesting stormwater runoff for Irrigation Use BMPs on your site:
Step 1: Identify the total area of irrigated landscape on the site, and the type of landscaping used.
Total Area of Irrigated Landscape: n/a
Type of Landscaping (Conservation Design or Active Turf) : Conservation design Step 2: Identify the planned total of all impervious areas on the proposed project from which runoff might be feasibly captured and stored for irrigation use. Depending on the configuration of buildings and other impervious areas on the site, you may consider the site as a whole, or parts of the site, to evaluate reasonable scenarios for capturing and storing runoff and directing the stored runoff to the potential use(s) identified in Step 1 above.
Total Area of Impervious Surfaces: n/a
Step 3: Cross reference the Design Storm depth for the project site (see Exhibit A of the WQMP Guidance Document) with the left column of Table 2-3 in Chapter 2 to determine the minimum area of Effective Irrigated Area per Tributary Impervious Area (EIATIA).
Enter your EIATIA factor: n/a
Step 4: Multiply the unit value obtained from Step 3 by the total of impervious areas from Step 2 to develop the minimum irrigated area that would be required.
Minimum required irrigated area : n/a
Step 5: Determine if harvesting stormwater runoff for irrigation use is feasible for the project by comparing the total area of irrigated landscape (Step 1) to the minimum required irrigated area (Step 4).
Minimum required irrigated area (Step 4) Available Irrigated Landscape (Step 1) n/a n/a
PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies - 13 -
Toilet Use Feasibility
Complete the following steps to determine the feasibility of harvesting stormwater runoff for toilet flushing uses on your site:
Step 1: Identify the projected total number of daily toilet users during the wet season, and account for any periodic shut downs or other lapses in occupancy:
Projected Number of Daily Toilet Users: n/a
Project Type: Residential
Step 2: Identify the planned total of all impervious areas on the proposed project from which runoff might be feasibly captured and stored for toilet use. Depending on the configuration of buildings and other impervious areas on the site, you may consider the site as a whole, or parts of the site, to evaluate reasonable scenarios for capturing and storing runoff and directing the stored runoff to the potential use(s) identified in Step 1 above.
Total Area of Impervious Surfaces: n/a
Step 3: Enter the Design Storm depth for the project site (see Exhibit A) into the left column of Table 2- 2 in Chapter 2 to determine the minimum number or toilet users per tributary impervious acre (TUTIA).
Enter your TUTIA factor: n/a
Step 4: Multiply the unit value obtained from Step 3 by the total of impervious areas from Step 2 to develop the minimum number of toilet users that would be required.
Minimum number of toilet users: n/a
Step 5: Determine if harvesting stormwater runoff for toilet flushing use is feasible for the project by comparing the Number of Daily Toilet Users (Step 1) to the minimum required number of toilet users (Step 4).
Minimum required Toilet Users (Step 4) Projected number of toilet users (Step 1)
Other Non-Potable Use Feasibility
Are there other non-potable uses for stormwater runoff on the site (e.g. industrial use)? See Chapter 2 of the Guidance for further information. If yes, describe below. If no, write N/A.
N/A
Step 1: Identify the projected average daily non-potable demand, in gallons per day, during the wet season and accounting for any periodic shut downs or other lapses in occupancy or operation.
Average Daily Demand: N/A
Step 2: Identify the planned total of all impervious areas on the proposed project from which runoff might be feasibly captured and stored for the identified non-potable use. Depending on the configuration of buildings and other impervious areas on the site, you may consider the site as a whole, or parts of the site, to evaluate reasonable scenarios for capturing and storing runoff and directing the stored runoff to the potential use(s) identified in Step 1 above.
Total Area of Impervious Surfaces: N/A
PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies - 14 -
Step 3: Enter the Design Storm depth for the project site (see Exhibit A) into the left column of Table 2- 4 in Chapter 2 to determine the minimum demand for non-potable uses per tributary impervious acre.
Enter the factor from Table 2-4: N/A
Step 4: Multiply the unit value obtained from Step 3 by the total of impervious areas from Step 2 to develop the minimum number of gallons per day of non-potable use that would be required.
Minimum required use: N/A
Step 5: Determine if harvesting stormwater runoff for other non-potable use is feasible for the project by comparing the projected average daily use (Step 1) to the minimum required non-potable use (Step 4).
Minimum required non-potable use (Step 4) Projected average daily use (Step 1)
N/A N/A
If Irrigation, Toilet and Other Use feasibility anticipated demands are less than the applicable minimum values, Harvest and Use BMPs are not required and you should proceed to utilize LID Bioretention and Biotreatment per Section 3.4.2 of the WQMP Guidance Document.
D.3 Bioretention and Biotreatment Assessment
Other LID Bioretention and Biotreatment BMPs as described in Chapter 2.4.7 of the WQMP Guidance Document are feasible on nearly all development sites with sufficient advance planning.
Select one of the following:
☐ LID Bioretention/Biotreatment BMPs will be used for some or all DMAs of the project as noted below in Section D.4 (note the requirements of Section 3.4.2 in the WQMP Guidance Document). ☐ A site-specific analysis demonstrating the technical infeasibility of all LID BMPs has been performed and is included in Appendix 5. If you plan to submit an analysis demonstrating the technical infeasibility of LID BMPs, request a pre-submittal meeting with the Copermittee to discuss this option. Proceed to Section E to document your alternative compliance measures.
PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies - 15 -
D.4 Feasibility Assessment Summaries
From the Infiltration, Harvest and Use, Bioretention and Biotreatment Sections above, complete Table D.2 below to summarize which LID BMPs are technically feasible, and which are not, based upon the established hierarchy.
Table D.2 LID Prioritization Summary Matrix
DMA
Name/ID
LID BMP Hierarchy No LID
(Alternative
Compliance) 1. Infiltration 2. Harvest and use 3. Bioretention 4. Biotreatment B1
C1
C2
C3
For those DMAs where LID BMPs are not feasible, provide a brief narrative below summarizing why they are not feasible, include your technical infeasibility criteria in Appendix 5, and proceed to Section E below to document Alternative Compliance measures for those DMAs. Recall that each proposed DMA must pass through the LID BMP hierarchy before alternative compliance measures may be considered.
N/A
PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies - 16 -
D.5 LID BMP Sizing
Each LID BMP must be designed to ensure that the Design Capture Volume will be addressed by the selected BMPs. First, calculate the Design Capture Volume for each LID BMP using the VBMP worksheet in Appendix F of the LID BMP Design Handbook. Second, design the LID BMP to meet the required VBMP using a method approved by the Copermittee. Utilize the worksheets found in the LID BMP Design Handbook or consult with your Copermittee to assist you in correctly sizing your LID BMPs. Complete Table D.3 below to document the Design Capture Volume and the Proposed Volume for each LID BMP. Provide the completed design procedure sheets for each LID BMP in Appendix 6. You may add additional rows to the table below as needed.
Table D.3 DCV Calculations for LID BMPs
DMA
Type/ID
DMA
Area
(square
feet)
Post-Project
Surface Type
Effective
Impervious
Fraction, If
DMA
Runoff
Factor
DMA
Areas x
Runoff
Factor
B1: Infiltration Basin
[A] [B] [C] [A] x [C]
C1 132538 ROOFS 1.00 0.89 118223.9
Design
Storm
Depth
(in)
Design
Capture
Volume,
VBMP (cubic
feet)
Proposed
Volume
on Plans
(cubic
feet)
C2 65141 CONCRETE OR
ASPHALT
1.00 0.89 58105.8
C3 111239 ORNAMENTAL
LANDSCAPING
0.10 0.11 12287.2
B1 3674 NATURAL
(A SOIL)
0.03 0.06 229.8
312592 188846.7 0.56 8812.8 9177.5
[B], [C] is obtained as described in Section 2.3.1 of the WQMP Guidance Document [E] is obtained from Exhibit A in the WQMP Guidance Document [G] is obtained from a design procedure sheet, such as in LID BMP Design Handbook and placed in Appendix 6
PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies - 17 -
Section E: Alternative Compliance (LID Waiver Program)
LID BMPs are expected to be feasible on virtually all projects. Where LID BMPs have been demonstrated to be infeasible as documented in Section D, other Treatment Control BMPs must be used (subject to LID waiver approval by the Copermittee). Check one of the following Boxes:
☒ LID Principles and LID BMPs have been incorporated into the site design to fully address all Drainage Management Areas. No alternative compliance measures are required for this project and thus this Section is not required to be completed.
- Or -
☐ The following Drainage Management Areas are unable to be addressed using LID BMPs. A site- specific analysis demonstrating technical infeasibility of LID BMPs has been approved by the Co- Permittee and included in Appendix 5. Additionally, no downstream regional and/or sub-regional LID BMPs exist or are available for use by the project. The following alternative compliance measures on the following pages are being implemented to ensure that any pollutant loads expected to be discharged by not incorporating LID BMPs, are fully mitigated.
List DMAs here.
PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies - 18 -
E.1 Identify Pollutants of Concern
Utilizing Table A.1 from Section A above which noted your project’s receiving waters and their associated EPA approved 303(d) listed impairments, cross reference this information with that of your selected Priority Development Project Category in Table E.1 below. If the identified General Pollutant Categories are the same as those listed for your receiving waters, then these will be your Pollutants of Concern and the appropriate box or boxes will be checked on the last row. The purpose of this is to document compliance and to help you appropriately plan for mitigating your Pollutants of Concern in lieu of implementing LID BMPs.
Table E.1 Potential Pollutants by Land Use Type
Priority Development
Project Categories and/or
Project Features (check those
that apply)
General Pollutant Categories
Bacterial
Indicators Metals Nutrients Pesticides
Toxic
Organic
Compounds
Sediments Trash &
Debris
Oil &
Grease
Detached Residential
Development P N P P N P P P
Attached Residential
Development P N P P N P P P (2)
Commercial/Industrial
Development P
(3) P P (1) P (1) P (5) P (1) P P
Automotive Repair
Shops N P N N P (4, 5) N P P
Restaurants
(>5,000 ft2) P N N N N N P P
Hillside Development
(>5,000 ft2) P N P P N P P P
Parking Lots
(>5,000 ft
2) P(6) P P (1) P (1) P (4) P (1) P P
Retail Gasoline Outlets N P N N P N P P
Project Priority Pollutant(s)
of Concern
P = Potential
N = Not Potential
(1) A potential Pollutant if non-native landscaping exists or is proposed onsite; otherwise not expected (2) A potential Pollutant if the project includes uncovered parking areas; otherwise not expected (3) A potential Pollutant is land use involving animal waste (4) Specifically petroleum hydrocarbons
(5) Specifically solvents
(6) Bacterial indicators are routinely detected in pavement runoff
PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies - 19 -
E.2 Stormwater Credits
Projects that cannot implement LID BMPs but nevertheless implement smart growth principles are potentially eligible for Stormwater Credits. Utilize Table 3-8 within the WQMP Guidance Document to identify your Project Category and its associated Water Quality Credit. If not applicable, write N/A.
Table E.2 Water Quality Credits
Qualifying Project Categories Credit Percentage2
Total Credit Percentage1
1Cannot Exceed 50%
2Obtain corresponding data from Table 3-8 in the WQMP Guidance Document
E.3 Sizing Criteria
After you appropriately considered Stormwater Credits for your project, utilize Table E.3 below to appropriately size them to the DCV, or Design Flow Rate, as applicable. Please reference Chapter 3.5.2 of the WQMP Guidance Document for further information.
Table E.3 Treatment Control BMP Sizing
DMA
Type/ID
DMA
Area
(square
feet)
Post-
Project
Surface
Type
Effective
Impervious
Fraction, If
DMA
Runoff
Factor
DMA
Area x
Runoff
Factor
Enter BMP Name / Identifier Here
[A] [B] [C] [A] x [C]
Design
Storm
Depth
(in)
Minimum
Design
Capture
Volume or
Design Flow
Rate (cubic
feet or cfs)
Total Storm
Water
Credit %
Reduction
Proposed
Volume
or Flow
on Plans
(cubic
feet or
cfs)
AT =
Σ[A]
Σ= [D] [E] F = DxE
G [F] X (1-[H]) [I]
[B], [C] is obtained as described in Section 2.3.1 from the WQMP Guidance Document [E] is for Flow-Based Treatment Control BMPs [E] = .2, for Volume-Based Control Treatment BMPs, [E] obtained from Exhibit A in the WQMP Guidance Document
[G] is for Flow-Based Treatment Control BMPs [G] = 43,560, for Volume-Based Control Treatment BMPs, [G] = 12 [H] is from the Total Credit Percentage as Calculated from Table E.2 above [I] as obtained from a design procedure sheet from the BMP manufacturer and should be included in Appendix 6
PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies - 20 -
E.4 Treatment Control BMP Selection
Treatment Control BMPs typically provide proprietary treatment mechanisms to treat potential pollutants in runoff, but do not sustain significant biological processes. Treatment Control BMPs must have a removal efficiency of a medium or high effectiveness as quantified below:
• High: equal to or greater than 80% removal efficiency • Medium: between 40% and 80% removal efficiency
Such removal efficiency documentation (e.g., studies, reports, etc.) as further discussed in Chapter 3.5.2 of the WQMP Guidance Document, must be included in Appendix 6. In addition, ensure that proposed Treatment Control BMPs are properly identified on the WQMP Site Plan in Appendix 1.
Table E.4 Treatment Control BMP Selection
Selected Treatment Control BMP
Name or ID1
Priority Pollutant (s) of
Concern to Mitigate2
Removal Efficiency
Percentage3
1 Treatment Control BMPs must not be constructed within Receiving Waters. In addition, a proposed Treatment Control BMP may be listed more than once if they possess more than one qualifying pollutant removal efficiency. 2 Cross Reference Table E.1 above to populate this column. 3 As documented in a Co-Permittee Approved Study and provided in Appendix 6.
PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies - 21 -
Section F: Hydromodification
F.1 Hydrologic Conditions of Concern (HCOC) Analysis
Once you have determined that the LID design is adequate to address water quality requirements, you will need to assess if the proposed LID Design may still create a HCOC. Review Chapters 2 and 3 (including Figure 3-7) of the WQMP Guidance Document to determine if your project must mitigate for Hydromodification impacts. If your project meets one of the following criteria which will be indicated by the check boxes below, you do not need to address Hydromodification at this time. However, if the project does not qualify for Exemptions 1, 2 or 3, then additional measures must be added to the design to comply with HCOC criteria. This is discussed in further detail below in Section F.2.
HCOC EXEMPTION 1: The Priority Development Project disturbs less than one acre. The Copermittee has the discretion to require a Project-Specific WQMP to address HCOCs on projects less than one acre on a case by case basis. The disturbed area calculation should include all disturbances associated with larger common plans of development.
Does the project qualify for this HCOC Exemption? Y N If Yes, HCOC criteria do not apply.
HCOC EXEMPTION 2: The volume and time of concentration 1 of storm water runoff for the post- development condition is not significantly different from the pre-development condition for a 2-year return frequency storm (a difference of 5% or less is considered insignificant) using one of the following methods to calculate:
• Riverside County Hydrology Manual
• Technical Release 55 (TR-55): Urban Hydrology for Small Watersheds (NRCS 1986), or derivatives thereof, such as the Santa Barbara Urban Hydrograph Method • Other methods acceptable to the Co-Permittee
Does the project qualify for this HCOC Exemption?
Y N
If Yes, report results in Table F.1 below and provide your substantiated hydrologic analysis in Appendix 7.
Table F.1 Hydrologic Conditions of Concern Summary
2 year – 24 hour
Pre-condition Post-condition % Difference
Time of
Concentration
INSERT VALUE
Volume (Cubic Feet) INSERT VALUE
1 Time of concentration is defined as the time after the beginning of the rainfall when all portions of the drainage basin are contributing to flow at the outlet.
PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies - 22 -
HCOC EXEMPTION 3: All downstream conveyance channels to an adequate sump (for example, Prado Dam, Lake Elsinore, Canyon Lake, Santa Ana River, or other lake, reservoir or naturally erosion resistant feature) that will receive runoff from the project are engineered and regularly maintained to ensure design flow capacity; no sensitive stream habitat areas will be adversely affected; or are not identified on the Co-Permittees Hydromodification Susceptibility Maps.
Does the project qualify for this HCOC Exemption?
Y N
If Yes, HCOC criteria do not apply and note below which adequate sump applies to this HCOC qualifier:
INSERT TEXT HERE
F.2 HCOC Mitigation
If none of the above HCOC Exemption Criteria are applicable, HCOC criteria is considered mitigated if they meet one of the following conditions:
a. Additional LID BMPS are implemented onsite or offsite to mitigate potential erosion or habitat impacts as a result of HCOCs. This can be conducted by an evaluation of site-specific conditions utilizing accepted professional methodologies published by entities such as the California Stormwater Quality Association (CASQA), the Southern California Coastal Water Research Project (SCCRWP), or other Co-Permittee approved methodologies for site-specific HCOC analysis.
b. The project is developed consistent with an approved Watershed Action Plan that addresses HCOC in Receiving Waters.
c. Mimicking the pre-development hydrograph with the post-development hydrograph, for a 2- year return frequency storm. Generally, the hydrologic conditions of concern are not significant, if the post-development hydrograph is no more than 10% greater than pre- development hydrograph. In cases where excess volume cannot be infiltrated or captured and reused, discharge from the site must be limited to a flow rate no greater than 110% of the pre-development 2-year peak flow.
Be sure to include all pertinent documentation used in your analysis of the items a, b or c in Appendix 7.
PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies - 23 -
Section G: Source Control BMPs
Source control BMPs include permanent, structural features that may be required in your project plans — such as roofs over and berms around trash and recycling areas — and Operational BMPs, such as regular sweeping and “housekeeping”, that must be implemented by the site’s occupant or user. The MEP standard typically requires both types of BMPs. In general, Operational BMPs cannot be substituted for a feasible and effective permanent BMP. Using the Pollutant Sources/Source Control Checklist in Appendix 8, review the following procedure to specify Source Control BMPs for your site:
1. Identify Pollutant Sources: Review Column 1 in the Pollutant Sources/Source Control Checklist. Check off the potential sources of Pollutants that apply to your site.
2. Note Locations on Project-Specific WQMP Exhibit : Note the corresponding requirements listed in Column 2 of the Pollutant Sources/Source Control Checklist. Show the location of each Pollutant source and each permanent Source Control BMP in your Project-Specific WQMP Exhibit located in Appendix 1.
3. Prepare a Table and Narrative: Check off the corresponding requirements listed in Column 3 in the Pollutant Sources/Source Control Checklist. In the left column of Table G.1 below, list each potential source of runoff Pollutants on your site (from those that you checked in the Pollutant Sources/Source Control Checklist). In the middle column, list the corresponding permanent, Structural Source Control BMPs (from Columns 2 and 3 of the Pollutant Sources/Source Control Checklist) used to prevent Pollutants from entering runoff. Add additional narrative in this column that explains any special features, materials or methods of construction that will be used to implement these permanent, Structural Source Control BMPs.
4. Identify Operational Source Control BMPs: To complete your table, refer once again to the Pollutant Sources/Source Control Checklist. List in the right column of your table the Operational BMPs that should be implemented as long as the anticipated activities continue at the site. Copermittee stormwater ordinances require that applicable Source Control BMPs be implemented; the same BMPs may also be required as a condition of a use permit or other revocable Discretionary Approval for use of the site.
PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies - 24 -
Table G.1 Permanent and Operational Source Control Measures Potential Sources of Runoff
pollutants
Permanent Structural Source
Control BMPs
Operational Source Control BMPs
Onsite storm drains inlets • Mark all inlet with the
words “only rain down
storm drain” or similar.
Catch basin markers may
be available from the
Riverside County Flood
Control and Water
Conservation District, call
951.55.1200 to verify
• Maintain and periodically
repaint
or replace inlet markings
• Provide Stormwater pollution
prevention information to new
site owners, lessees, or
operators.
• See applicable optional BMPs in
Fact Sheet SC-44, “Drainage
System Maintenance,” in the
CASQA Stormwater Quality
Handbooks at www.
cabmphandbooks.com
• Include the following in lease
agreements: “Tenant shall not
allow anyone to discharge
anything to storm drains or to
store or deposit materials so as to
create a potential discharge to
storm drains.”
Landscape/Outdoor Pesticide Us State that final landscape plans will accomplish all of the following.
• Preserve existing native trees,
shrubs, and ground cover to the
maximum extent possible.
• Design landscaping to minimize
irrigation and runoff, to promote
surface infiltration where
appropriate, and to minimize the
use of fertilizers and pesticides that
can contribute to
stormwater pollution.
• Where landscaped areas are used
to retain or detain stormwater,
specify plants that are tolerant to
saturated soil conditions.
• Consider using pest-resistant
plants, especially adjacent to
hardscape. To insure successful
establishment, select plants
appropriate to site soils, slopes,
climate, sun, wind,
rain, land use, air movement
• Maintain landscaping using
minimum or no pesticides.
• See applicable operational BMPs
in “What you should know for….
Landscape and Gardening” at
http://rcflood.org/stormwater/.
• Provide IPM information to new
owners, lessees and operators
Roofing, gutters and trim • Avoid roofing, gutters, and trim made of copper or other
unprotected metals that may
leach into runoff.
• See applicable operational BMPs
in “Guidelines for Maintaining
Your Swimming Pool, Jacuzzi and
Garden Fountain” at
http://rcflood.org/stormwater
PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies - 25 -
Section H: Construction Plan Checklist
Populate Table H.1 below to assist the plan checker in an expeditious review of your project. The first two columns will contain information that was prepared in previous steps, while the last column will be populated with the corresponding plan sheets. This table is to be completed with the submittal of your final Project-Specific WQMP.
Table H.1 Construction Plan Cross-reference
BMP No. or
ID
BMP Identifier and
Description
Corresponding Plan Sheet(s) BMP Location (Lat/Long)
INFIL INFILTRATION BASIN CONCEPTUAL GRADE PLAN SHEET 1 33°88’76” North 117°27’43” West
Note that the updated table — or Construction Plan WQMP Checklist — is only a reference tool to facilitate an easy comparison of the construction plans to your Project-Specific WQMP. Co-Permittee staff can advise you regarding the process required to propose changes to the approved Project-Specific WQMP.
PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies - 26 -
Section I: Operation, Maintenance and Funding
The Copermittee will periodically verify that Stormwater BMPs on your site are maintained and continue to operate as designed. To make this possible, your Copermittee will require that you include in Appendix 9 of this Project-Specific WQMP:
1. A means to finance and implement facility maintenance in perpetuity, including replacement cost.
2. Acceptance of responsibility for maintenance from the time the BMPs are constructed until responsibility for operation and maintenance is legally transferred. A warranty covering a period following construction may also be required.
3. An outline of general maintenance requirements for the Stormwater BMPs you have selected.
4. Figures delineating and designating pervious and impervious areas, location, and type of Stormwater BMP, and tables of pervious and impervious areas served by each facility. Geo- locating the BMPs using a coordinate system of latitude and longitude is recommended to help facilitate a future statewide database system.
5. A separate list and location of self-retaining areas or areas addressed by LID Principles that do not require specialized O&M or inspections but will require typical landscape maintenance as noted in Chapter 5, pages 85-86, in the WQMP Guidance. Include a brief description of typical landscape maintenance for these areas.
Your local Co-Permittee will also require that you prepare and submit a detailed Stormwater BMP Operation and Maintenance Plan that sets forth a maintenance schedule for each of the Stormwater BMPs built on your site. An agreement assigning responsibility for maintenance and providing for inspections and certification may also be required.
Details of these requirements and instructions for preparing a Stormwater BMP Operation and Maintenance Plan are in Chapter 5 of the WQMP Guidance Document.
Maintenance Mechanism: Insert text here.
Will the proposed BMPs be maintained by a Home Owners’ Association (HOA) or Property Owners Association (POA)?
Y N
Include your Operation and Maintenance Plan and Maintenance Mechanism in Appendix 9. Additionally, include all pertinent forms of educational materials for those personnel that will be maintaining the proposed BMPs within this Project-Specific WQMP in Appendix 10.
PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies - 27 -
Appendix 1: Maps and Site Plans
Location Map, WQMP Site Plan and Receiving Waters Map
PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies THOMAS BROS. MAP PS 744 SR.ID 6-3
VICINITY MAP
----====:::::§~S:~<ifi15= -
SEC. 24 T.3S. R.6H
PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies RIVERSIDE COUNTY FLOODCONTROL AND WATERCONSERVATION DISTRICTIsohyetal Mapfor the 85th Percentile24 hour Storm EventJuly 2011Rain Gage LocationsPR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies Santa Ana River Reach 3
Ô
Ô
Ô
Ô
Ô
Ô
T
Ô
Ô
Reach 1b
Day Canyon Creek
Lake Mathews
Mockingbird Reservoir
Lake Evans
Lake Norconian
Prado Basin Management Zone
Santa Ana River Reach 3
Day Canyon Cre
Aliso Creek
Anza Park
Drain
San Antonio Creek
Chino Creek Reach 2
Chino CreekReach 1B
Chino Creek
Reach 1A
Temescal Creek
Reach 2
Temescal Creek Reach 2
Temescal Creek Reach 1a
Santa Ana River
Reach 3
Santa Ana River Reach 2
Santa Ana River
Reach 2
Mill Creek(Prado Area)
Cucamong
Cucamonga Creek
Reach 1
Teq(Sy
ch 2
Santa Ana River Reach 3
Aliso Creek
Cucamonga Creek Reach 1
Santa Ana River Reach 4
Chino Creek Reach 1B
d Canyon Creek
Sunnyslope Channel
180702030804
180702030605
180702031001
180702030706
180702030606
180702030705
180702030703
180702030603
180702030803
180702030902
180702030702
180702030802
180702030604
180702030704
180702031002
180701060505
180702030901 180702030604
I 15
CHINO
MISSION
ONTARIO
EUCLID
RIVERSIDE
MAGNOLIA
VAN BUREN
6TH
EDISON
GROVE
CAJALCO
LA SIERRA
MAIN
ARLINGTON
5TH
ARCHIBALD
RIVER
VICTORIA
PINE
TYLER
JURUPA
END
SCHAEFER
HAVEN
CORONA
RAMONA
CHINO VALLEY
CENTRAL
PHILADELPHIA
PHILLIPS
PEYTON
LIMONITE
INDIANA
LINCOLN
BAIN
PEDLEY
PALM
BELLEGRAVE
ETIWANDA
MOUNTAIN
CHASE
EL SOBRANTE
8TH
SIERRA
WELLS
GRAND
HAMNER
HOLE
4TH
CHINO HILLS
ADAMS
RIMPAU
10TH
BROCKTON
JACKSON
MONROE
LA PALMA
RAILROAD
CEDAR
TROTH
CHERRY
PIPELINE
SERRANO
PIERCE
RUBIDOUX
DEWEY
CITRUS
RIVERSIDE FWY
EL PRADO
STATE HWY 241
STATE HWY 60
UPPER
MCALLISTER
MARKET
STATE HWY 71
CORYDON
GREEN RIVER
GALENA
FULLERTON
WASHINGTON
BEACH
7TH
JEFFERSON
NORCO
MADISON
MILLIKEN
MERRILL
ARMSTRONG
PROMENADE
MARY
WEIR CANYON
BORDER
CLOVERDALE
VINEYARD
CAMINO REAL
BON VIEW
HOLMES
MOCKINGBIRD CANYON
WALKER
MAPLE
PALISADES
BEECH
SOQUEL CANYON
3RD
COLORADO
VALLEY
TAYLOR
AGUA MANSA
HELLMAN
MULBERRY
CRESTA
EUCALYPTUS
AVIATION
CARBON CANYON
YORBA LINDA
CALIFORNIA
2ND
RIVERVIEW
CLEVELAND
AVON
CHANDLER
GRANT
YUMA
2ND
JURUPA
STATE HWY 60
BON VIEW
CENTRAL
MISSION
6TH
HAMNER
LIMONITE
STATE HWY 241
ONTARIO
North
East
South
West
Home
PROJECT SITE
PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies