APPENDIX D: PART 1
Project WQMP
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Project Specific Preliminary Water Quality Management
Plan
A Template for Projects located within the Santa Ana Watershed Region of Riverside County Project Title: Mikasa Luxury Villas Residential Development Project Public Works No: GP-2022-02467
Design Review/Case No: PR-2021-001114
Original Date Prepared: 01/18/2022
Revision Date(s): 12/13/2022, 09/27/2023
Prepared for Compliance with
Regional Board Order No. R8-2010-0033
Con
tact Information:
Prepared for:
Hugo Lepe
Century Heritage Builders
Prep
ared by:
Andrew Grechuta
Civil Engineer
G&G Engineering, Inc.
1251 N. Manassero St., STE 402
Anaheim, CA 92807
Preliminary
Final
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OWNER’S CERTIFICATION
This Project-Specific Water Quality Management Plan (WQMP) has been prepared for A & L Capital, LLC by Andrew Grechuta, RCE 52312 for the Mikasa Luxury Villas project.
This WQMP is intended to comply with the requirements of the City of Riverside for, Planning Case No. GP-2022- 02467 w hich 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 the 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." 12/18/2022
Owner’s
Signature Date
A & L Capital, LLC
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.”
Prep
arer’s Signature Date
Andrew Grechuta Civil Engineer
Prep
arer’s Printed Name Preparer’s Title/Position
Preparer’s Licensure: C52312
12/18/2022
Developer
PR-
2021-
0246
7 which includes the requirement for the preparation and implementation of a Project-Specific WQMP. 001114 - 3 -
Table of Contents
Section A: Project and Site Information........................................................................................................ 5 A.1 Maps and Site Plans ............................................................................................................................ 5 A.2 Receiving Waters ................................................................................................................................ 6 A.3 Additional Permits/Approvals required for the Project: .................................................................... 6 Section B: Optimize Site Utilization (LID Principles) ..................................................................................... 7 Section C: Delineate Drainage Management Areas (DMAs) ......................................................................... 8 Section D: Implement LID BMPs ................................................................................................................. 10 D.1 Infiltration Applicability .................................................................................................................... 10 D.2 Harvest and Use Assessment ............................................................................................................ 11 D.3 Bioretention and Biotreatment Assessment .................................................................................... 13 D.4 Feasibility Assessment Summaries ................................................................................................... 14 D.5 LID BMP Sizing .................................................................................................................................. 15 Section E: Alternative Compliance (LID Waiver Program) .......................................................................... 16 Section F: Hydromodification ..................................................................................................................... 17 F.1 Hydrologic Conditions of Concern (HCOC) Analysis .......................................................................... 17 F.2 HCOC Mitigation ................................................................................................................................ 18 Section G: Source Control BMPs ................................................................................................................. 19 Section H: Construction Plan Checklist ....................................................................................................... 19 Section I: Operation, Maintenance and Funding ........................................................................................ 20
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List of Tables
Table A.1 Identification of Receiving Waters ................................................................................................ 6 Table A.2 Other Applicable Permits .............................................................................................................. 6 Table C.1 DMA Classifications ....................................................................................................................... 8 Table C.2 Type ‘A’, Self-Treating Areas ......................................................................................................... 8 Table C.3 Type ‘B’, Self-Retaining Areas ....................................................................................................... 8 Table C.4 Type ‘C’, Areas that Drain to Self-Retaining Areas ........................................................................ 9 Table C.5 Type ‘D’, Areas Draining to BMPs ................................................................................................. 9 Table D.1 Infiltration Feasibility .................................................................................................................. 10 Table D.2 LID Prioritization Summary Matrix ............................................................................................. 14 Table D.3 DCV Calculations for LID BMPs ................................................................................................... 15 Table F.1 Hydrologic Conditions of Concern Summary .............................................................................. 17 Table G.1 Permanent and Operational Source Control Measures ............................................................. 19 Table H.1 Construction Plan Cross-reference ............................................................................................. 19
List of Appendices
Appendix 1: Maps and Site Plans ................................................................................................................ 21 Appendix 2: Construction Plans .................................................................................................................. 22 Appendix 3: Soils Information ..................................................................................................................... 23 Appendix 4: Historical Site Conditions ........................................................................................................ 24 Appendix 5: LID Infeasibility ........................................................................................................................ 25 Appendix 6: BMP Design Details ................................................................................................................. 26 Appendix 7: Hydromodification .................................................................................................................. 27 Appendix 8: Source Control ........................................................................................................................ 28 Appendix 9: O&M ....................................................................................................................................... 29 Appendix 10: Educational Materials ....................................................................................................... - 30 -
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Section A: Project and Site Information
Luxury apartment complexes in Riverside
PROJECT INFORMATION
Type of Project: Commercial
Ward Area: Ward Area 6
C o m m u n i t y N a m e :
Development Name: Mikasa Luxury Villas
PROJECT LOCATION
Latitude & Longitude (DMS): 33.920141, -117.479078
Project Watershed and Sub-Watershed: Santa Ana; Santa Ana River, Reach 3/4 APN(s): 143-040-011 & 143-040-012
Map Book and Page No.: Lots 23 & 29 of El Rincon, Book 11, Pages 85 and 86 of maps.
PROJECT CHARACTERISTICS
Proposed or Potential Land Use(s) Apartment complexes
Proposed or Potential SIC Code(s) 6513
Area of Impervious Project Footprint (SF) 174,159
Total Area of proposed Impervious Surfaces within the Project Limits (SF)/or Replacement Insert text here 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 (SF) Insert text here.
Is the project located within any MSHCP Criteria Cell? Y N If so, identify the Cell number: Insert text here.
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) B&C What is the Water Quality Design Storm Depth for the project? 0 .63” A.1 Maps and Site Plans
Appendix 1 includes a map of the local vicinity and existing si te. In addition, WQMP Site Plan, located in Appendix 1, includes 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
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A.2 Receiving Waters
I n o r d e r o f u p s t r e a m t o d o w n s t r eam, the receiving waters that th e p r o j e c t s i t e i s t r i b u t a r y t o a r e a s follows. A map of the receiving waters is included in Appendix 1.
Table A.1 Identification of Receiving Waters
Receiving Waters Hydrologic
Unit
EPA Approved
303(d) List
Impairments
Designated
Beneficial Uses
Proximity to RARE
Beneficial Use
Temescal Creek, Reach 1 801.25 None REC1, REC2, WARM, WILD N/A
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 Conditional Use Permit
City of Riverside Design Review
City of Riverside Building Permit
City of Riverside Grading Permit
City of Riverside Construction Permit
Y
Y
Y
Y
Y
N
N
N
N
N
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Section B: Optimize Site Utilization (LID Principles)
Site Optimization
Does the project identify and preserve existing drainage patterns? If so, how? If not, why? The proposed conditions involve full development of the property as attached apartment units as 18 buildings. Drainage patterns will generally remain as in the existing condition, from the center of the property, being a high point, draining towards the publi c streets. The project will be split into 3 drainage management areas. The water will drain into drainage inlets and will be treated via biotreatment BMP (Filterra). Treat stormwater will be conveyed via parkway drain to the curbs and gutters along Hedrick Ave and Jones Ave.
Does the project identify and protect existing vegetation? If so, how? If not, why? The proposed conditions involve full development of the propert y with 24% of proposed pervious area.
Does the project identify and preserve natural infiltration capacity? If so, how? If not, why? The soil within the project site is silty sand which has a low infiltration rate. Potential liquification of existing soils restrict infiltration.
Does the project identify and minimize impervious area? If so, how? If not, why? Project’s nature does not allow substitution of pavement for la ndscaping. Landscaping has been proposed to the maximum extent practicable.
Does the project identify and disperse runoff to adjacent pervious areas? If so, how? If not, why? Roof runoff is directed to the proposed paved area to run over as a sheet flow and discharge into on-site proposed biotreatment BMP (Filterra) through underground storm pipe and drainage inlet.
The site is not a hillside. Stormwater runoff is diverted/ piped to the drainage inlet/ storage basin areas. Overflow to flow to the public street gutter and catch basin. - 8 -
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., Typ e 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) Area (Sq. Ft.) DMA Type
DMA A1 Concrete or Asphalt 58,000 D
DMA A2 Turf Block 16,946 A
DMA B1 Concrete or Asphalt 62,140 D
DMA B2 Turf Block 18,089 A
DMA C1 Concrete or Asphalt 34,019 D
DMA C2 Turf Block 14,091 A
Table C.2 Type ‘A’, Self-Treating Areas
DMA Name or ID Area (Sq. Ft.) Stabilization Type Irrigation Type (if any) DMA A2 16,946 Sheet flow-landscape area Sprinklers
DMA B2 18,089 Sheet flow-landscape area Sprinklers
DMA C2 14,091 Sheet flow-landscape area Sprinklers
Table C.3 Type ‘B’, Self-Retaining Areas NOT APPLICABLE Self-Retaining Area
T y p e ‘ C ’ D M A s t h a t a r e d r a i n i n g t o t h e S e l f - R e t a i n i n g 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]
[𝐷] = [𝐵] +
[𝐵] ∙[ 𝐶 ]
[𝐴]
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Table C.4 Type ‘C’, Areas that Drain to Self-Retaining Areas NOT APPLICABLE DMA Receiving Self-Retaining DMA
DMA Name/ ID
Area
(square feet)
Post-project
surface type
Runoff
factor Product
DMA name /ID
Area (square
feet) Ratio
[A] [B] [C] = [A] x [B] [D] [C]/[D]
Table C.5 Type ‘D’, Areas Draining to BMPs
DMA Name or ID BMP Name or ID
DMA A1 BMP2- Filterra
DMA B1 BMP2- Filterra
DMA C1 BMP2- Filterra
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Section D: Implement LID BMPs
D.1 Infiltration Applicability
Is there an approved downstream ‘Highest and Best Use’ for stormwater runoff (ref: Chapter 2.4.4 of the WQMP Guidance Document)? Y N
If yes has been checked, Infiltration BMPs shall not be used fo r the site. 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 is required by the City of Riverside to confirm present and past site characteristics that may affect the use of Infiltration BMPs, see Appendix 3.
Is this project classified as a small project consistent with t he 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 I n f i l t r a t i o n B M P s a n d i s d i s c u s s e d i n t h e W Q M P G u i d a n c e D o c u m e nt 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: A,B,C possible liquification …have measured in-situ infiltration rates of less than 1.6 inches / hour? X If Yes, list affected DMAs: All DMAs
…have significant cut and/or fi ll conditions that would preclud e 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: A,B,C possible liquification
If you answered “Yes” to any of the questions above for any DMA , Infiltration BMPs should not be used for those DMAs.
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D.2 Harvest and Use Assessment
The following conditions apply:
☐ Reclaimed water will be used for the non-potable water demands for the project. ☐ Downstream water rights may be i mpacted by Harvest and Use as a pproved by the Regional Board (verified with the City of Riverside).
☐ The Design Capture Volume will be addressed using Infiltration Only BMPs. (Harvest and Use BMPs are still encouraged, but are not required as the Design C apture Volume will be infiltrated or evapotranspired).
☒ None of the above.
Harvest and Use BMPs need not be assessed for the site.
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 s ite, 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. Depen ding 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 s i t e ( s e e E x h i b i t A o f t h e W Q M P 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).
T h e p r o j e c t E I A T I A f a c t o r: N/A
Step 4: Multiply the unit value obtained from Step 3 by the tot al 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 irrigatio n 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
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Toilet Use Feasibility
Complete the following steps to determine the feasibility of ha rvesting stormwater runoff for toilet flushing uses on your site:
Step 1: Identify the projected total number of daily toilet use rs 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: Commercial
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- 1 in Chapter 2 to determine the minimum number or toilet users per tributary impervious acre (TUTIA).
The project TUTIA factor: N/A
Step 4: Multiply the unit value obtained from Step 3 by the tot al 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 fl ushing 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 toil et users (Step 1)
N/A N/A
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.
None
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-po table 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
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Step 3: Enter the Design Storm depth for the project site (see Exhibit A) into the left column of Table 2- 3 in Chapter 2 to determine the minimum demand for non-potable uses per tributary impervious acre.
The project factor: N/A
Step 4: Multiply the unit value obtained from Step 4 by the tot al of impervious areas from Step 3 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 Average Daily non-potable demand (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 dem ands are less than the applicable minimum values, Harvest and Use BMPs are not required and you should proceed to utilize LID Bioretention and Biotreatment, unless a site-specific analysis has been completed that demonstrates technical infeasibility as noted in D.3 below.
D.3 Bioretention and Biotreatment Assessment
Other LID Bioretention and Biotreatment BMPs as described in Ch apter 2.4.7 of the WQMP Guidance Document are feasible on nearly all development sites with sufficient advance planning.
For the project, the following applies:
☒ 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 infeasibi l i t y o f a l l L I D B M P s h a s b e e n 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 me eting with the City of Riverside to discuss this option. If you checked this box, then proceed to Section E to document your alternative compliance measures.
☐ None of the above.
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D.4 Feasibility Assessment Summaries
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 DMA A1
DMA B1
DMA C1
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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 City of Riverside. Utilize the worksheets found in the LID BMP Design Handbook or consult with the City of Rive rside to assist you in correctl y 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
Enter BMP Name / Identifier Here
[A] [B] [C] [A] x [C]
DMA A1 58,000 C o n c r e t e
or
Asphalt
1 0.89 51,736
Design
Storm
Depth
(in)
Design Capture
Volume, VBMP
(cubic feet)
Proposed
Volume
on Plans
(cubic
feet)
DMA A2 16,946 Turf bloc k 0 . 1 0.11 1871.8
DMA B1 62,140 C o n c r e t e
or
Asphalt
1 0.89 55,429.2
DMA B2 18,089 Turf bloc k 0 . 1 0.11 1998.1
DMA C1 34,019 Concrete
or
Asphalt
1 0.89 30,344.9
DMA C2 14,091 Turf bloc k 0 . 1 0.11 1556.5
AT = Σ[A]
Σ= [D]
=
142,936.5
[E]
= 0.63
[F] = [D]x[E]
12 = 7444.6
[G]
8,280
[B], [C] are obtained from Section 2.3.1 of the WQMP Guidance Document [E] is obtained from Exhibit A of the WQMP Guidance Document [G] is obtained from LID BMP design procedure sheet, placed in Appendix 6
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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 Co ntrol BMPs must be used (subject to confirmation of LID waiver approval by the Regional Board). For the project, the following applies:
☒ LID Principles and LID BMPs have been incorporated into the site design to fully address all Drainage Management Areas. No al ternative compliance measures are required for this project and thus this Section is not required to be completed.
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☐ The following Drainage Management Areas are unable to be addressed using LID BMPs. A site- specific analysis demonstrating technical infeasibility of LID B M P s h a s b e e n a p p r o v e d b y t h e Regional Board and included in Appendix 5. Additionally, no dow nstream regional and/or sub- r e g i o n a l L I D B M P s e x i s t o r a r e a v a i l a b l e f o r u s e b y t h e p r o j e c t. The alternative compliance m e a s u r e s o n t h e f o l l o w i n g p a g e s a r e b e i n g i m p l e m e n t e d t o e n s u r e that any pollutant loads expected to be discharged by not incorporating LID BMPs, are fully mitigated.
If 1st box is checked, then remove entirely the following subsections E.1 through E.4 If 2nd box is checked, then list affected DMAs here with a brief narrative.
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Section F: Hydromodification
F.1 Hydrologic Conditions of Concern (HCOC) Analysis
Once you have determined that the LID design is adequate to add ress 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 fol lowing criteria which will be indicated by the check boxes below, you do not need to address Hydromodifica t i o n a t t h i s t i m e . H o w e v e r , i f t h e project does not qualify for Exemptions 1, 2 or 3, then additio nal measures must be added to the design to comply with HCOC criteria. This is discussed in further detail below in Section F.2.
The project does create a Hydrologic Condition of Concern, not meeting the criteria for HCOC Exemption as shown below:
HCOC EXEMPTION 1: T h e P r i o r i t y D e v e l o p m e n t P r o j e c t d i s t u r b s l e s s t h a n o n e a c r e . T h e C i t y o f Riverside 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 calcu lation should include all disturbances associated with larger common plans of development.
Does the project qualify for this HCOC Exemption? Y N
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 r e t u r n f r e q u e n c y s t o r m ( a d i f f e r e n c e o f 5 % o r l e s s i s c o n s i d e r ed insignificant) using one of the following methods to calculate:
• Riverside County Hydrology Manual
• Technical Release 55 (TR-55): Urban Hydrology for Small Watersh eds (NRCS 1986), or derivatives thereof, such as the Santa Barbara Urban Hydrograph Method • Other methods acceptable to the City of Riverside
Does the project qualify for this HCOC Exemption? Y N Results included in Table F.1 below and hydrologic analysis included 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 INSERT VALUE INSERT VALUE
Flow (CFS) INSERT VALUE INSERT VALUE INSERT VALUE
Volume (Cubic Feet) INSERT VALUE INSERT VALUE 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.
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HCOC EXEMPTION 3: All downstream conveyance channels to an adequate sump (Prado Dam, Santa Ana River) that will receiv e r u n o f f f r o m t h e p r o j e c t a r e 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 Sensitivity Maps.
Does the project qualify for this HCOC Exemption? Y N
F.2 HCOC Mitigation
As an alternative to the HCOC Exemption Criteria above, HCOC cr iteria is considered mitigated if the project meets one of the following conditions, as indicated:
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 evalu ation of site-specific conditions utilizing accepted professional m ethodologies published by enti t i e s s u c h a s t h e C a l i f o r n i a 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 Waters hed Action Plan that addresses HCOC in Receiving Waters.
c. Mimicking the pre-development hydrograph with the post-deve lopment 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 pr e-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.
d. None of the above.
Be sure to include all pertinent documentation used in your analysis of the items a, b or c in Appendix 7.
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Section G: Source Control BMPs
The following table identifies the potential sources of runoff pollutants for this project and specifies how they are addressed through permanent controls and operational BMPs:
Table G.1 Permanent and Operational Source Control Measures Potential Sources of Runoff
pollutants
Permanent Structural Source
Control BMPs
Operational Source Control BMPs
Roadways Provide storm drain stenciling
and signage (S1)
Education for property owners,
tenants, and occupants (N1)
Residential Lots Driveways of minimal widths. Activity Restrict ions (N2) Irrigated landscaped areas Use efficient irrigation system and landscape design. (S4)
Irrigation System and Landscape
Management (N3)
Common Area Litter Control (N4)
Parking Lot Street Sweeping (N5)
Drainage Facility Inspection and
Maintenance (N6)
Section H: Construction Plan Checklist
Table H.1 Construction Plan Cross-reference
BMP No.
or ID
BMP Identifier and Description Plan Sheet
Number(s)
Latitude / Longitude
BMP 1 ADS Flexstorm inlet filter WQMP
Exhibit
33.920380, -117.479927
33.920217, -117.479929
33.920069, -117.479942
BMP 2 Filterra WQMP
Exhibit
33.920021, -117.480197
33.921050, -117.480221
33.919819, -117.477979
- 20 -
Section I: Operation, Maintenance and Funding
As required by the City of Riverside, the following Operation, Maintenance and Funding details are provided as summarized:
1. A means to finance and implement facility maintenance in perpet uity, including replacement cost.
2. A c c e p t a n c e of r e s p o n s i b i l it y f o r m a in t e n a n c e f r o m t h e t i m e t h e B M P s a r e c o n s t r u c t e d u n t i l responsibility for operation and maintenance is legally transferred.
3. An outline of general maintenance requirements for the Stormwater BMPs selected.
4. Figures delineating and designating pervious and impervious are as, location, and type of Stormwater BMP, and tables of pervious and impervious areas served by each facility.
5. A separate list and location of self-retaining areas or areas a ddressed by LID Principles that do not require specialized O&M or inspections but will require typ ical landscape maintenance as noted in Chapter 5, pages 85-86, in the WQMP Guidance.
S e e A p p e n d i x 9 f o r a d e t a i l e d S t o r m w a t e r B M P O p e r a t i o n a n d M a i ntenance Plan that sets forth a maintenance schedule for each of the Stormwater BMPs built on s ite, and an agreement assigning responsibility for maintenance and providing for inspections and certification.
Details of these requirements and instructions for preparing a S t o r m w a t e r B M P O p e r a t i o n a n d Maintenance Plan are in Chapter 5 of the WQMP Guidance Document.
Maintenance Mechanism:
Will the proposed BMPs be maintained by a Home Owners’ Associat ion (HOA) or Property Owners Association (POA)?
Y N
Operation and Maintenance Plan and Maintenance Mechanism is inc luded in Appendix 9. Educational materials for those personnel that will be maintaining the proposed BMPs within this Project-Specific WQMP are included in Appendix 10.
- 21 -
Appendix 1: Maps and Site Plans
Location Map, WQMP Site Plan and Receiving Waters Map
1/27/22, 2:06 PM Google Maps
https://www.google.com/maps/@33.9209006,-117.4790107,18z?hl=en 1/1 Map dat
a ©2022 Google 1 00 ft
- 22 -
Appendix 2: Construction Plans
Grading and Drainage Plans
PRELIMINARY GRADING PLAN
FOR MIKASA LUXURY VILLAS
LEGEND
PROJECT TEAM:
SITE ADRESS:
LEGAL DESCRIPTION:AREA:
BUILDING J
FF: 720.00
BUILDING A
FF: 717.00
BUILDING B
FF: 717.00
BUILDING D
FF: 718.00
BUILDING C
FF: 718.00
BUILDING L
FF: 723.00BUILDING N
FF: 719.00
BUILDING K
FF: 722.00
BUILDING Q
FF: 723.00
BUILDING M
FF: 721.00
BUILDING G
FF: 727.00
BUILDING O
FF: 727.00
BUILDING I
FF: 728.00
BUILDING H
FF: 719.50
BUILDING E
FF: 722.50
BUILDING P
FF: 721.00
BUILDING F
FF: 724.50
FOOTPRINT AREA:
8769 SQ.FT
FOOTPRINT AREA:
9097 SQ.FT
FOOTPRINT AREA:
5013 SQ.FT
FOOTPRINT AREA:
2683 SQ.FT
FOOTPRINT AREA:
2217 SQ.FT
JONES AVE.
HEDRICK AVE.
DECORATIVE PAVERS
DRIVEWAY
ASPHALT
DRIVEWAY
ASPHALT
DRIVEWAY
ASPHALTDRIVEWAY
ASPHALTDRIVEWAY
(E) CARPORT
(E) 2-CAR
GARAGE
(E) 2-CAR
GARAGE
(E)STORAGE
(E) 2-STORY
MULTY FAMILY
RESIDENCE
(E) 1-STORY
SINGLE FAMILY
RESIDENCE
(E) 1-STORY
SINGLE FAMILY
RESIDENCE
(E) 1-STORY
SINGLE FAMILY
RESIDENCE
(E) 1-STORY
SINGLE FAMILY
RESIDENCE
(E) 1-STORY
SINGLE FAMILY
RESIDENCE
(E) 1-STORY
SINGLE FAMILY
RESIDENCE
(E) 1-STORY
SINGLE FAMILY
RESIDENCE
(E) 1-STORY
SINGLE FAMILY
RESIDENCE
(E) 1-STORY
SINGLE FAMILY
RESIDENCE
(E) CARPORT (E) CARPORT
(E) CARPORT
(E) 2-STORY
MULTY FAMILY
RESIDENCE
(E) 2-STORY
MULTY FAMILY
RESIDENCE
(E) 2-STORY
MULTY FAMILY
RESIDENCE
(E) 1-STORY
SINGLE FAMILY
RESIDENCE
(E) 1-STORY
SINGLE FAMILY
RESIDENCE
(E) 1-STORY
SINGLE FAMILY
RESIDENCE
(E) POOL
COOK AVE.
JONES AVE.
HEDRICK AVE.
PATH
PATH
PATH
PATH
ASPHALT
DRIVEWAY
26 27
PATH
40 PATH
2 3
4 5
6 891011
14 15
16 17
18 19
20 21
22 23
7 12
30 32 33 34
37 38
28 FOOTPRINT AREA:
2217 SQ.FT
FOOTPRINT AREA:
2217 SQ.FT
FOOTPRINT AREA:
2217 SQ.FT
FOOTPRINT AREA:
2229 SQ.FT
FOOTPRINT AREA:
2229 SQ.FT
FOOTPRINT AREA:
2229 SQ.FT
1 FOOTPRINT AREA:
4317 SQ.FT
FOOTPRINT AREA:
963 SQ.FT
FOOTPRINT AREA:
9097 SQ.FT
FOOTPRINT AREA:
9097 SQ.FT
24 35
PATH
PATH
13 25
39 36
FOOTPRINT AREA:
8769 SQ.FT
31 1
2 3
4 29
PRELIMINARY
GRADING PLANC-2
Underground Service Alert
Call: TOLL FREE
811
WWW.CALL811.COM
SHEET NO. REVISIONS PREPARED UNDER SUPERVISION OF:
MIKASA LUXURY VILLAS
ANDREW GRECHUTA
R.C.E. NO. C523312
DATE
EXP. DATE: 12-31-23
4618 JONES AVE & 4663 HEDRICK AVE
RIVERSIDE, CA 92505
PLAN DATE: 06-04-23
FOOTPRINT AREA:
8769 SQ.FT
FOOTPRINT AREA:
9097 SQ.FT
FOOTPRINT AREA:
5013 SQ.FT
FOOTPRINT AREA:
2683 SQ.FT
FOOTPRINT AREA:
2217 SQ.FT
JONES AVE.
HEDRICK AVE.
DECORATIVE PAVERS
DRIVEWAY
ASPHALT
DRIVEWAY
ASPHALT
DRIVEWAY
ASPHALTDRIVEWAY
ASPHALTDRIVEWAY
(E) CARPORT
(E) 2-CAR
GARAGE
(E) 2-CAR
GARAGE
(E)STORAGE
(E) 2-STORY
MULTY FAMILY
RESIDENCE
(E) 1-STORY
SINGLE FAMILY
RESIDENCE
(E) 1-STORY
SINGLE FAMILY
RESIDENCE
(E) 1-STORY
SINGLE FAMILY
RESIDENCE
(E) 1-STORY
SINGLE FAMILY
RESIDENCE
(E) 1-STORY
SINGLE FAMILY
RESIDENCE
(E) 1-STORY
SINGLE FAMILY
RESIDENCE
(E) 1-STORY
SINGLE FAMILY
RESIDENCE
(E) 1-STORY
SINGLE FAMILY
RESIDENCE
(E) 1-STORY
SINGLE FAMILY
RESIDENCE
(E) CARPORT (E) CARPORT
(E) CARPORT
(E) 2-STORY
MULTY FAMILY
RESIDENCE
(E) 2-STORY
MULTY FAMILY
RESIDENCE
(E) 2-STORY
MULTY FAMILY
RESIDENCE
(E) 1-STORY
SINGLE FAMILY
RESIDENCE
(E) 1-STORY
SINGLE FAMILY
RESIDENCE
(E) 1-STORY
SINGLE FAMILY
RESIDENCE
(E) POOL
COOK AVE.
JONES AVE.
HEDRICK AVE.
PATH
PATH
PATH
PATH
ASPHALT
DRIVEWAY
26 27
PATH
40 PATH
2 3
4 5
6 891011
14 15
16 17
18 19
20 21
22 23
7 12
30 32 33 34
37 38
28 FOOTPRINT AREA:
2217 SQ.FT
FOOTPRINT AREA:
2217 SQ.FT
FOOTPRINT AREA:
2217 SQ.FT
FOOTPRINT AREA:
2229 SQ.FT
FOOTPRINT AREA:
2229 SQ.FT
FOOTPRINT AREA:
2229 SQ.FT
1 FOOTPRINT AREA:
4317 SQ.FT
FOOTPRINT AREA:
963 SQ.FT
FOOTPRINT AREA:
9097 SQ.FT
FOOTPRINT AREA:
9097 SQ.FT
24 35
PATH
PATH
13 25
39 36
FOOTPRINT AREA:
8769 SQ.FT
31 1
2 3
4 29
BUILDING J
FF: 720.00
BUILDING A
FF: 717.00
BUILDING B
FF: 717.00
BUILDING D
FF: 718.00
BUILDING C
FF: 718.00
BUILDING L
FF: 723.00BUILDING N
FF: 719.00
BUILDING K
FF: 722.00
BUILDING Q
FF: 723.00
BUILDING M
FF: 721.00
BUILDING G
FF: 727.00
BUILDING O
FF: 727.00
BUILDING I
FF: 728.00
BUILDING H
FF: 719.50
BUILDING E
FF: 722.50
BUILDING P
FF: 721.00
BUILDING F
FF: 724.50
PRELIMINARY STORM DRAIN PLAN
FOR MIKASA LUXURY VILLAS
CONSTRUCTION NOTES:
PRELIMINARY
STORM DRAIN
PLAN
C-3
Underground Service Alert
Call: TOLL FREE
811
WWW.CALL811.COM
SHEET NO. REVISIONS PREPARED UNDER SUPERVISION OF:
MIKASA LUXURY VILLAS
ANDREW GRECHUTA
R.C.E. NO. C523312
DATE
EXP. DATE: 12-31-23
4618 JONES AVE & 4663 HEDRICK AVE
& 4705 HEDRICK AVE
RIVERSIDE, CA 92505
PLAN DATE: 07-27-23
- 23 -
Appendix 3: Soils Information
Geotechnical Study and Other Infiltration Testing Data
See Soils Report
- 24 -
Appendix 4: Historical Site Conditions
Phase I Environmental Site Assessment or Other Information on Past Site Use
- 25 -
Appendix 5: LID Infeasibility
LID Technical Infeasibility Analysis
- 26 -
Appendix 6: BMP Design Details
BMP Sizing, Design Details and other Supporting Documentation
Date
I = 0.20 in/hr
DMA
Type/ID
DMA Area
(square feet)
Post-Project
Surface Type
(use pull-down menu)
Effective
Imperivous
Fraction, If
DMA
Runoff
Factor
DMA Areas x
Runoff Factor
Design
Rainfall
Intensity
(in/hr)
Design Flow
Rate (cfs)
Proposed Flow
Rate (cfs)
DMA A1 58000 Concrete or Asphalt 1 0.89 51736
DMA A2 16946 Turf block 0.1 0.110458 1871.8
1 1
1 1
1 1
1 1
1 1
1 1
1 1
1 1
1 1
1 1
1 1
1 74946 53607.8 0.20 0.2 0.28
Notes:
Santa Ana Watershed - BMP Design Flow Rate, QBMP
(Rev. 10-2011)
Legend:
Required Entries
Calculated Cells
(Note this worksheet shall only be used in conjunction with BMP designs from the LID BMP Design Handbook ) Company Name G&G Engineering, Inc. 9/20/2023
Designed by Andrew Grechuta Case No
Company Project Number/Name Mikasa Luxury Villas
Design Rainfall Intensity
Total
DMAs
BMP Identification
BMP NAME / ID BMP 2- FILTERRA
Must match Name/ID used on BMP Design Calculation Sheet Design Rainfall Depth
Drainage Management Area Tabulation
Insert additional rows if needed to accommodate all DMAs draining to the BMP
Date
I = 0.20 in/hr
DMA
Type/ID
DMA Area
(square feet)
Post-Project
Surface Type
(use pull-down menu)
Effective
Imperivous
Fraction, If
DMA
Runoff
Factor
DMA Areas x
Runoff Factor
Design
Rainfall
Intensity
(in/hr)
Design Flow
Rate (cfs)
Proposed Flow
Rate (cfs)
DMA B1 62140 Concrete or Asphalt 1 0.89 55428.9
DMA B2 18089 Turf block 0.1 0.110458 1998.1
1 1
1 1
1 1
1 1
1 1
1 1
1 1
1 1
1 1
1 1
1 1
1 80229 57427 0.20 0.3 0.34
Notes:
Drainage Management Area Tabulation
Insert additional rows if needed to accommodate all DMAs draining to the BMP Design Rainfall Intensity
Total
DMAs
BMP Identification
BMP NAME / ID BMP 2- FILTERRA
Must match Name/ID used on BMP Design Calculation Sheet Design Rainfall Depth
Designed by Andrew Grechuta Case No
Company Project Number/Name Mikasa Luxury Villas
Santa Ana Watershed - BMP Design Flow Rate, QBMP
(Rev. 10-2011)
Legend:
Required Entries
Calculated Cells
(Note this worksheet shall only be used in conjunction with BMP designs from the LID BMP Design Handbook ) Company Name G&G Engineering, Inc. 9/20/2023
Date
I = 0.20 in/hr
DMA
Type/ID
DMA Area
(square feet)
Post-Project
Surface Type
(use pull-down menu)
Effective
Imperivous
Fraction, If
DMA
Runoff
Factor
DMA Areas x
Runoff Factor
Design
Rainfall
Intensity
(in/hr)
Design Flow
Rate (cfs)
Proposed Flow
Rate (cfs)
DMA C1 34019 Concrete or Asphalt 1 0.89 30344.9
DMA C2 14091 Turf block 0.1 0.110458 1556.5
1 1
1 1
1 1
1 1
1 1
1 1
1 1
1 1
1 1
1 1
1 1
1 48110 31901.4 0.20 0.1 0.14
Notes:
Santa Ana Watershed - BMP Design Flow Rate, QBMP
(Rev. 10-2011)
Legend:
Required Entries
Calculated Cells
(Note this worksheet shall only be used in conjunction with BMP designs from the LID BMP Design Handbook ) Company Name G&G Engineering, Inc. 9/20/2023
Designed by Andrew Grechuta Case No
Company Project Number/Name Mikasa Luxury Villas
Design Rainfall Intensity
Total
DMAs
BMP Identification
BMP NAME / ID BMP 2- FILTERRA
Must match Name/ID used on BMP Design Calculation Sheet Design Rainfall Depth
Drainage Management Area Tabulation
Insert additional rows if needed to accommodate all DMAs draining to the BMP
Media bed 175 in/hr (cfs) FT FTPD FTIBC FTBSV
4x4 0.065 X X X X
4x6 / 6x4 0.097 X X
4x8 / 8x4 0.097 X X X
6x6 0.146 X
4x13 / 13x4 0.211 X X X
8x8 0.259 X
8x10 / 10x8 0.324 X
6x8 / 8x6 0.194 X X X
6x12 / 12x6 0.292 X X X
8x10.5 0.340 X
8x12 0.389 X X X
8x12.5 0.405 X
14x8 0.454 X X X
16x8 0.519 X X X
18x8 0.583 X X X
20x8 0.648 X X X
22x8 0.713 X X X
Filterra Type