Attachment 3x - PC Staff Report 11-7-24-MND and Tech Studies — Riverside City Council, April 22, 2025

GENERAL EARTHWORK AND GRADING SPECIFICATIONS

1.0 GENERAL INTENT
These specifications present general procedures and requirements for grading and earthwork as shown on the approved grading plans, including preparation of areas to be filled, placement of fill, installations of subdrains, and excavations. The recommendations contained in the geotechnical report are a part of the earthwork and grading specifications and shall supersede the provisions contained hereinafter in the case of conflict.

Evaluations performed by the consultant during the course of grading may result in new recommendations which could supersede these specifications or the recommendations of the geotechnical report.

2.0 EARTHWORK OBSERVATIONS ANO TESTING
Prior to the commencement of grading, a qualified geotechnical consultant (soils engineer and engineering geologist, and their representatives) shall be employed for the purpose of observing earthwork procedures and testing the fills for conformance with the recommendations of the geotechnical report and these specifications. It will be necessary that the consultant provide adequate testing and observations so that he may determine that the work was accomplished as specified. It shall be the responsibility of the contractor to assist the consultant and keep him apprised of work schedules and changes so that he may schedule his personnel accordingly.

It shall be the sole responsibility of the contractor to provide adequate equipment and methods to accomplish the work in accordance with applicable grading codes or agency ordinances, these specifications and approved grading plans. If, in the opinion of the consultant, unsatisfactory conditions, such as questionable soil, poor moisture conditions, inadequate compaction, adverse weather, etc., are resulting in a quality of work less than required in these specifications, the consultant will be empowered to reject the work and recommend that construction be stopped until the unsatisfactory conditions are rectified.

Maximum dry density tests used to determine the degree of compaction will be performed in accordance with the American Society of Testing and Materials, test method ASTM D1557-09.

3.0 PREPARATION OF AREAS TO BE FILLED

3.1 Clearing and Grubbing
All brush, vegetation, and debris shall be removed or piled and otherwise disposed of.

3.2 Processing
The existing ground which is determined to be satisfactory for support of fill shall be scarified to a minimum depth of 6 inches. Existing ground which is not satisfactory shall be overexcavated as specified in the following section. Scarification shall continue until the soils are broken down and free of large clay lumps or clods and until the working surface is reasonably uniform and free of uneven features which would inhibit uniform compaction.

3.3 Overexcavation
Soft, dry, spongy, highly fractured or otherwise unsuitable ground, extending to such depth that surface processing cannot adequately improve the condition, shall be overexcavated down to firm ground, approved by the consultant.

3.4 Moisture Conditioning
Overexcavated and processed soils shall be watered, dried-back, blended, and/or mixed, as required to attain a uniform moisture content near optimum.

3.5 Recompaction
Overexcavation and processed soils which have been properly mixed and moisture-conditioned shall be recompacted to a minimum relative compaction of 90 percent.

Soil Exploration Co., Inc. Appendix E-1
PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies

3.6 Benching
Where fills are to be placed on ground with slopes steeper than 5:1 (horizontal : vertical), the ground shall be stepped or benched.

The lowest bench shall be a minimum of 15 feet wide, shall be at least 2 feet deep, shall expose firm materials, and shall be approved by the consultant. Other benches shall be excavated in firm materials for a minimum width of 4 feet. Ground sloping flatter than 5:1 (horizontal : vertical) shall be benched or otherwise overexcavated when considered necessary by the consultant.

3. 7 Approval
All areas to receive fill, including processed areas, removal areas and toe-of-fill benches shall be approved by the consultant prior to fill placement.

4.0 . FILL MATERIAL

4.1 General
Material to be placed as fill shall be free of organic matter and other deleterious substances, and shall be approved by the consultant.

Soils of poor gradation, expansion, or strength characteristics shall be placed in areas designated by consultant or shall be mixed with other soils to serve as satisfactory fill material.

4.2 Oversize
Oversize materials defined as rock, or other irreducible material with maximum dimension greater than 12 inches, shall not be buried or placed in fills, unless the location, materials, and disposal methods are specifically approved by the consultant. Oversize disposal operations shall be such that nesting of oversize material does not occur, and such that the oversize material is completely surrounded by compacted or densified fill. Oversize material shall not be placed within 10 feet vertically of finish grade or within the range of future utilities or underground construction, unless specifically approved by the consultant.

4.3 Import
If importing of fill material is required for grading, the import material shall meet the requirements of Section 4.1.

5.0 FILL PLACEMENT and COMPACTION

5.1 Fill Lifts
Approved fill material shall be placed in areas prepared to receive fill in near-horizontal layers not exceeding 6 inches in compacted thickness. The consultant may approve thicker lifts if testing indicates the grading procedures are such that adequate compaction is being achieved with lifts of greater thickness. Each layer shall be spread evenly and shall be thoroughly mixed during spreading to attain uniformity of material and moisture in each layer.

5.2 Fill Moisture
Fill layers at a moisture content less than optimum shall be watered and mixed, and wet fill layers shall be aerated by scarification or shall be blended with drier material. Moisture conditioning and mixing of fill layers shall continue until the fill material is at a uniform moisture content at or near optimum.

5.3 Compaction of Fill
After each layer has been evenly spread, moisture-conditioned, and mixed, it shall be uniformly compacted to not less than 90 percent of maximum dry density. Compaction equipment shall be adequately sized and shall be either specifically designed for soil compaction or of proven reliability, to efficiently achieve the specified degree of compaction.

Soil Exploration Co., Inc. Appendix E-2
PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies

5.4 Fill Slopes
Compacting of slopes shall be accomplished, in addition to nonnal compacting procedures, by backrolling of slopes with sheepsfoot rollers at frequent increments of 2 to 3 feet in fill elevation gain, or by other methods producing satisfactory results. At the completion of grading, the relative compaction of the slope out to the slope face shall be at least 90 percent.

5.5 Compaction Testing
Field-tests to check the fill moisture and degree of compaction will be perfonned by the consultant. The location and frequency of tests shall be at the consultant's discretion. In general, the tests will be taken at intervals not exceeding 2 feet in vertical rise and/or 1,000 cubic yards of embankment.

6.0 SUBDRAIN INSTALLATION
Subdrain systems, if required, shall be installed in approved ground to confonn to the approximate alignment and details shown on the plans or herein. The subdrain location or materials shall not be changed or modified without the approval of the consultant. The consultant, however, may recommend and upon approval, direct changes in subdrain line, grade or material. All subdrains should be surveyed for line and grade after installation and sufficient time shall be allowed for the surveys, prior to commencement of filling over the subdrain.

7.0 EXCAVATION
Excavations and cut slopes will be examined during grading. If directed by the consultant, further excavation or overexcavation and refilling of cut areas shall be performed, and/or remedial grading of cut slopes shall be perfonned. Where fill-over-cut slopes are to be graded, unless otherwise approved, the cut portion of the slope shall be made and approved by the consultant prior to placement of materials for construction of the fill portion of the slope.

8.0 TRENCH BACKFILLS
Trench excavations for utility pipes shall be backfilled under engineering supervision.

After the utility pipe has been laid, the space under and around the pipe shall be backfilled with clean sand or approved granular soil to a depth of at least one foot over the top of the pipe. The sand backfill shall be unifonnly jetted into place before the controlled backfill is placed over the sand.

The onsite materials, or other soils approved by the soil engineer, shall be watered and mixed as necessary prior to placement in lifts· over the sand backfill.

The controlled backfill shall be compacted to at least 90 percent of the maximum dry density as detennined by the ASTM D1557-09 test method.

Field density tests and inspection of the backfill procedures shall be made by the soil engineer during backfilling to see that proper moisture content and unifonn compaction is being maintained. The contractor shall provide test holes and exploratory pits as required by the soil engineer to enable sampling and testing.

Soil Exploration Co., Inc. Appendix E-3
PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies ..

PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies TO·
SOIL

EXPLORATION
COMPANY , INC.

Soil Engineering , Environmental Engineering, Materials Testing, Geology December 16, 2019
Project No 13167-01
West Coast Hotels Group LLC
19215 Wild Mustang Ct.

Apple Valley, CA 92307
ATTENTION.

SUBJECT
Hitesh Patel
California Building Code (CBC) 2016 Seismic Update, Proposed 8.B±Acre, 14 Lot Residential Subdivision, SEC Victoria Avenue and La Sierra Avenue, City of Riverside, California
REFERENCES Soil Exploration Co., Inc , "Preliminary Geotechnical I nvestigation/Liquefaction Evaluation/Infiltration Tests Report, Proposed 8.8± Acre, 14 Lot Residential Subdivision, SEC of Victoria Avenue and La Sierra Avenue (APN 136-220-016), City of Riverside, California" Dated January 24, 2014 (Project No. 13167-01).

Introduction
As requested, we have prepared the following updated seismic parameters for the subject site.

CBC 2016 Seismic Parameters
The CBC (2016) seismic parameters for the site are tabulated below:
2016 CBC- SEISMIC PARAMETERS
Site Coordinates
Latitude I Lonaitude

33.8875 I -117.4619
Mapped Spectral Response Acceleration s. = 1.500 S1 = 0.600 Site Coefficients (Class "D") Fa= 1.00 Fv = 1.50
Maximum Considered Earthquake (MCE)
I SMs = 1.500 SM1 = 0.900 SDectral ResDonse Acceleration Design Spectral Response Acceleration Sos = 1.000 So, = 0.600 Parameters Seismic Design Category D
Peak Ground Accelerat ion (PGA) 0.514g
References ·
• Earthquake .usgs.gov/research/hazmaps/des1gn
• 2016 California Building Code, California Code of Regulations. Trtle 24, Part 2, Volume 2 of 2, Section 1613, Earthquake Loads
7535 Jurupa Ave., Unit C • Riverside, CA 92504 • Tel: (951) 688-7200 • Fax: (951) 688-7100 [email protected] • www.soilexp.com
PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies Victoria Ave & La Sierra Ave.

Riverside , California
Foundation Plan ReviewlAdditional Observations and Testing Project No. 13167-01
December 16, 2019
Soil Exploration Co., Inc should review the foundation plans and observe andlor test at the following stages of construction:
• Dunng any additional grading or fill placement
• Following footings excavation and prior to placement of footing materials • During all utility trench backfills and street subgrade/base compaction. • Following wetting of slab subgrade (1.2.X optimum to a depth of at least 6") and prior to placement of slab materials.
• When any unusual conditions are encountered.

Limitation
Soil Exploration Co., Inc. has striven to perform our services within the limits prescribed by our client, and in a manner consistent with the usual thoroughness and competence of reputable soils engineers practicing under similar circumstances. No other representation, express or implied, and no warranty or guarantee is included or intended by virtue of the services performed or reports, opinion, documents, or otherwise supplied
Closure
If you should have any questions regarding this report, please do not hesitate to contact our office. We appreciate this opportuni to be of service.

Very truly yours,
Soil Exploration
Gene K. Luu, PE 53417
Project Engineer
Distribution: (1) Addressee ([email protected]) Attachments Figure 1 Site Location Map
Soil Exploration Co., Inc . Pagel
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PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies - 30 -

Appendix 4: Historical Site Conditions
Phase I Environmental Site Assessment or Other Information on Past Site Use

PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies - 31 -

Appendix 5: LID Infeasibility
LID Technical Infeasibility Analysis

PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies - 32 -

Appendix 6: BMP Design Details
BMP Sizing, Design Details and other Supporting Documentation

PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies Date
D85= 0.56 inches
DMA
Type/ID
DMA Area
(square feet)
Post-Project Surface
Type
Effective
Imperivous
Fraction, If
DMA
Runoff
Factor
DMA Areas x
Runoff Factor
Design
Storm
Depth (in)
Design Capture
Volume, VBMP
(cubic feet)
Proposed
Volume on
Plans (cubic
feet)
C1 132538 Roofs 1.00 0.89 118223.9
C2 65141 Concrete or Asphalt 1.00 0.89 58105.8
C3 111239 Ornamental
Landscaping 0.1 0.11 12287.2
B1 3674 Natural (A Soil) 0.03 0.06 229.8
1 1
1 1
1 1
1 1
1 1
1 1
1 1
1 1
1 1
1 312592 188846.7

0.56 8812.8 9177.5
Notes:

Total
85th Percentile, 24-hour Rainfall Depth,
from the Isohyetal Map in Handbook Appendix E
Insert additional rows if needed to accommodate all DMAs draining to the BMP Santa Ana Watershed - BMP Design Volume, VBMP
(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 Adkan Engineers 1/31/2022
Designed by Israel Duque Case No
Company Project Number/Name Warmington- Tract 36713
BMP Identification
Drainage Management Area Tabulation
Design Rainfall Depth
BMP NAME / ID Inflitration basin
Must match Name/ID used on BMP Design Calculation Sheet PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies Company Name: Date:

AT = 7.4 acres
b) Enter VBMP determined from Section 2.1 of this Handbook VBMP= 8,832 ft3 I = 2.85 in/hr
FS = 3
D1 = D1 = 5.7 ft
1 ft
e) Enter depth to historic high ground water (measured from top of basin) 15 ft 15 ft
D2 = 4.0 ft
DMAX = 4.0 ft
z = 2 :1
dB = 2.5 ft
AS = 3533 ft2
AD = 3,671 ft2
Volume = 44 ft3
Depth = 1 ft
Area = 44 ft2

36.0 in
Notes:
a) Tributary area (BMP subarea)
g) D2 is the smaller of:
d) Enter the depth of freeboard (at least 1 ft)
h) DMAX is the smaller value of D1 and D2 but shall not exceed 5 feet Design Volume
a) Basin side slopes (no steeper than 4:1) Slope no steeper than 4:1 Maximum Depth
a) Infiltration rate
b) Factor of Safety (See Table 1, Appendix A: "Infiltration Testing" from this BMP Handbook)
c) Calculate D1
Basin Geometry
f) Enter depth to top of bedrock or impermeable layer (measured from top of basin) I (in/hr) x 72 hrs
12 (in/ft) x FS
Depth to groundwater - (10 ft + freeboard) and
Depth to impermeable layer - (5 ft + freeboard)
Calculated Cells
Adkan Engineers

ISRAEL DUQUE
Infiltration Basin - Design Procedure
(Rev. 03-2012)
BMP ID Legend: Required Entries
d) Proposed Design Surface Area
c) Minimum bottom surface area of basin (AS= VBMP/dB)
b) Proposed basin depth (excluding freeboard)
Forebay
c) Forebay surface area (minimum)
Width (W) =
b) Forebay depth (height of berm/splashwall. 1 foot min.) a) Forebay volume (minimum 0.5% VBMP)
d) Full height notch-type weir
PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies - 33 -

Appendix 7: Hydromodification
Supporting Detail Relating to Hydrologic Conditions of Concern

PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies Infiltration Basin Bottom Area (sf) 3674
Basin Top Area (sf) 4899
Depth of Basin (ft) 2.5
Open Basin Volume Provided (cf) 10716
Rock Storage depth (ft) 4.6
Rock Storage Volume (40% void) (cf) 6755
Total Flood Volume Stored 17472
Ex. 2-yr 24-hr Storm Volume (cf) 8233
Prop. 2-yr 24-hr Storm Volume (cf) 26528
Allowable 2-yr 24-hr Storm Volume
(mitigated to 110% of existing) (cf) 9056
Prop. 2-yr 24-hr Storm Volume (cf) 26528
Total Flood Volume Stored 17472
Remaining Storm Volume 9056
Basin Storage Volume Calculations
PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies EX2YR24HR Page 1 of 9
U n i t H y d r o g r a p h A n a l y s i s
Copyright (c) CIVILCADD/CIVILDESIGN, 1989 - 2008, Version 8.1 Study date 02/22/24 File: EX2YR242.out
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ ------------------------------------------------------------------------ Riverside County Synthetic Unit Hydrology Method
RCFC & WCD Manual date - April 1978
Program License Serial Number 5006
--------------------------------------------------------------------- English (in-lb) Input Units Used
English Rainfall Data (Inches) Input Values Used
English Units used in output format
--------------------------------------------------------------------- -------------------------------------------------------------------- Drainage Area = 7.00(Ac.) = 0.011 Sq. Mi.

Drainage Area for Depth-Area Areal Adjustment = 7.00(Ac.) = 0.011 Sq. Mi.

Length along longest watercourse = 596.00(Ft.)
Length along longest watercourse measured to centroid = 300.00(Ft.) Length along longest watercourse = 0.113 Mi.

Length along longest watercourse measured to centroid = 0.057 Mi.

Difference in elevation = 26.00(Ft.)
Slope along watercourse = 230.3356 Ft./Mi.

Average Manning's 'N' = 0.030
Lag time = 0.038 Hr.

Lag time = 2.26 Min.
25% of lag time = 0.56 Min.
40% of lag time = 0.90 Min.

Unit time = 5.00 Min.

Duration of storm = 24 Hour(s)
User Entered Base Flow = 0.00(CFS)
2 YEAR Area rainfall data:

Area(Ac.)[1] Rainfall(In)[2] Weighting[1*2]

7.00 1.80 12.60
100 YEAR Area rainfall data:

Area(Ac.)[1] Rainfall(In)[2] Weighting[1*2]

7.00 6.00 42.00
STORM EVENT (YEAR) = 2.00
Area Averaged 2-Year Rainfall = 1.800(In)
Area Averaged 100-Year Rainfall = 6.000(In)
Point rain (area averaged) = 1.800(In)
Areal adjustment factor = 100.00 %
Adjusted average point rain = 1.800(In)
Sub-Area Data:

Area(Ac.) Runoff Index Impervious %

7.000 72.00 0.100
Total Area Entered = 7.00(Ac.)
RI RI Infil. Rate Impervious Adj. Infil. Rate Area% F AMC2 AMC-1 (In/Hr) (Dec.%) (In/Hr) (Dec.) (In/Hr)

72.0 53.4 0.537 0.100 0.489 1.000 0.489 Sum (F) = 0.489
Area averaged mean soil loss (F) (In/Hr) = 0.489
Minimum soil loss rate ((In/Hr)) = 0.244
(for 24 hour storm duration)
Soil low loss rate (decimal) = 0.820
--------------------------------------------------------------------- U n i t H y d r o g r a p h
VALLEY S-Curve
-------------------------------------------------------------------- Unit Hydrograph Data
--------------------------------------------------------------------- Unit time period Time % of lag Distribution Unit Hydrograph (hrs) Graph % (CFS) PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies EX2YR24HR Page 2 of 9
--------------------------------------------------------------------- 1 0.083 221.634 46.905 3.309 2 0.167 443.269 41.886 2.955 3 0.250 664.903 7.981 0.563 4 0.333 886.537 3.228 0.228 Sum = 100.000 Sum= 7.055
----------------------------------------------------------------------- The following loss rate calculations reflect use of the minimum calculated loss rate subtracted from the Storm Rain to produce the maximum Effective Rain value Unit Time Pattern Storm Rain Loss rate(In./Hr) Effective (Hr.) Percent (In/Hr) Max | Low (In/Hr) 1 0.08 0.07 0.014 ( 0.867) 0.012 0.003 2 0.17 0.07 0.014 ( 0.863) 0.012 0.003 3 0.25 0.07 0.014 ( 0.860) 0.012 0.003 4 0.33 0.10 0.022 ( 0.857) 0.018 0.004 5 0.42 0.10 0.022 ( 0.853) 0.018 0.004 6 0.50 0.10 0.022 ( 0.850) 0.018 0.004 7 0.58 0.10 0.022 ( 0.847) 0.018 0.004 8 0.67 0.10 0.022 ( 0.843) 0.018 0.004 9 0.75 0.10 0.022 ( 0.840) 0.018 0.004 10 0.83 0.13 0.029 ( 0.837) 0.024 0.005 11 0.92 0.13 0.029 ( 0.834) 0.024 0.005 12 1.00 0.13 0.029 ( 0.830) 0.024 0.005 13 1.08 0.10 0.022 ( 0.827) 0.018 0.004 14 1.17 0.10 0.022 ( 0.824) 0.018 0.004 15 1.25 0.10 0.022 ( 0.820) 0.018 0.004 16 1.33 0.10 0.022 ( 0.817) 0.018 0.004 17 1.42 0.10 0.022 ( 0.814) 0.018 0.004 18 1.50 0.10 0.022 ( 0.811) 0.018 0.004 19 1.58 0.10 0.022 ( 0.807) 0.018 0.004 20 1.67 0.10 0.022 ( 0.804) 0.018 0.004 21 1.75 0.10 0.022 ( 0.801) 0.018 0.004 22 1.83 0.13 0.029 ( 0.798) 0.024 0.005 23 1.92 0.13 0.029 ( 0.795) 0.024 0.005 24 2.00 0.13 0.029 ( 0.791) 0.024 0.005 25 2.08 0.13 0.029 ( 0.788) 0.024 0.005 26 2.17 0.13 0.029 ( 0.785) 0.024 0.005 27 2.25 0.13 0.029 ( 0.782) 0.024 0.005 28 2.33 0.13 0.029 ( 0.779) 0.024 0.005 29 2.42 0.13 0.029 ( 0.775) 0.024 0.005 30 2.50 0.13 0.029 ( 0.772) 0.024 0.005 31 2.58 0.17 0.036 ( 0.769) 0.030 0.006 32 2.67 0.17 0.036 ( 0.766) 0.030 0.006 33 2.75 0.17 0.036 ( 0.763) 0.030 0.006 34 2.83 0.17 0.036 ( 0.760) 0.030 0.006 35 2.92 0.17 0.036 ( 0.756) 0.030 0.006 36 3.00 0.17 0.036 ( 0.753) 0.030 0.006 37 3.08 0.17 0.036 ( 0.750) 0.030 0.006 38 3.17 0.17 0.036 ( 0.747) 0.030 0.006 39 3.25 0.17 0.036 ( 0.744) 0.030 0.006 40 3.33 0.17 0.036 ( 0.741) 0.030 0.006 41 3.42 0.17 0.036 ( 0.738) 0.030 0.006 42 3.50 0.17 0.036 ( 0.735) 0.030 0.006 43 3.58 0.17 0.036 ( 0.732) 0.030 0.006 44 3.67 0.17 0.036 ( 0.729) 0.030 0.006 45 3.75 0.17 0.036 ( 0.726) 0.030 0.006 46 3.83 0.20 0.043 ( 0.722) 0.035 0.008 47 3.92 0.20 0.043 ( 0.719) 0.035 0.008 48 4.00 0.20 0.043 ( 0.716) 0.035 0.008 49 4.08 0.20 0.043 ( 0.713) 0.035 0.008 50 4.17 0.20 0.043 ( 0.710) 0.035 0.008 51 4.25 0.20 0.043 ( 0.707) 0.035 0.008 52 4.33 0.23 0.050 ( 0.704) 0.041 0.009 53 4.42 0.23 0.050 ( 0.701) 0.041 0.009 54 4.50 0.23 0.050 ( 0.698) 0.041 0.009 55 4.58 0.23 0.050 ( 0.695) 0.041 0.009 56 4.67 0.23 0.050 ( 0.692) 0.041 0.009 57 4.75 0.23 0.050 ( 0.689) 0.041 0.009 58 4.83 0.27 0.058 ( 0.686) 0.047 0.010 59 4.92 0.27 0.058 ( 0.683) 0.047 0.010 60 5.00 0.27 0.058 ( 0.680) 0.047 0.010 61 5.08 0.20 0.043 ( 0.677) 0.035 0.008 62 5.17 0.20 0.043 ( 0.674) 0.035 0.008 63 5.25 0.20 0.043 ( 0.672) 0.035 0.008 64 5.33 0.23 0.050 ( 0.669) 0.041 0.009 65 5.42 0.23 0.050 ( 0.666) 0.041 0.009 66 5.50 0.23 0.050 ( 0.663) 0.041 0.009 67 5.58 0.27 0.058 ( 0.660) 0.047 0.010 68 5.67 0.27 0.058 ( 0.657) 0.047 0.010 69 5.75 0.27 0.058 ( 0.654) 0.047 0.010 70 5.83 0.27 0.058 ( 0.651) 0.047 0.010 71 5.92 0.27 0.058 ( 0.648) 0.047 0.010 72 6.00 0.27 0.058 ( 0.645) 0.047 0.010 PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies EX2YR24HR Page 3 of 9
73 6.08 0.30 0.065 ( 0.643) 0.053 0.012 74 6.17 0.30 0.065 ( 0.640) 0.053 0.012 75 6.25 0.30 0.065 ( 0.637) 0.053 0.012 76 6.33 0.30 0.065 ( 0.634) 0.053 0.012 77 6.42 0.30 0.065 ( 0.631) 0.053 0.012 78 6.50 0.30 0.065 ( 0.628) 0.053 0.012 79 6.58 0.33 0.072 ( 0.626) 0.059 0.013 80 6.67 0.33 0.072 ( 0.623) 0.059 0.013 81 6.75 0.33 0.072 ( 0.620) 0.059 0.013 82 6.83 0.33 0.072 ( 0.617) 0.059 0.013 83 6.92 0.33 0.072 ( 0.614) 0.059 0.013 84 7.00 0.33 0.072 ( 0.612) 0.059 0.013 85 7.08 0.33 0.072 ( 0.609) 0.059 0.013 86 7.17 0.33 0.072 ( 0.606) 0.059 0.013 87 7.25 0.33 0.072 ( 0.603) 0.059 0.013 88 7.33 0.37 0.079 ( 0.600) 0.065 0.014 89 7.42 0.37 0.079 ( 0.598) 0.065 0.014 90 7.50 0.37 0.079 ( 0.595) 0.065 0.014 91 7.58 0.40 0.086 ( 0.592) 0.071 0.016 92 7.67 0.40 0.086 ( 0.589) 0.071 0.016 93 7.75 0.40 0.086 ( 0.587) 0.071 0.016 94 7.83 0.43 0.094 ( 0.584) 0.077 0.017 95 7.92 0.43 0.094 ( 0.581) 0.077 0.017 96 8.00 0.43 0.094 ( 0.579) 0.077 0.017 97 8.08 0.50 0.108 ( 0.576) 0.089 0.019 98 8.17 0.50 0.108 ( 0.573) 0.089 0.019 99 8.25 0.50 0.108 ( 0.571) 0.089 0.019 100 8.33 0.50 0.108 ( 0.568) 0.089 0.019 101 8.42 0.50 0.108 ( 0.565) 0.089 0.019 102 8.50 0.50 0.108 ( 0.563) 0.089 0.019 103 8.58 0.53 0.115 ( 0.560) 0.094 0.021 104 8.67 0.53 0.115 ( 0.557) 0.094 0.021 105 8.75 0.53 0.115 ( 0.555) 0.094 0.021 106 8.83 0.57 0.122 ( 0.552) 0.100 0.022 107 8.92 0.57 0.122 ( 0.550) 0.100 0.022 108 9.00 0.57 0.122 ( 0.547) 0.100 0.022 109 9.08 0.63 0.137 ( 0.544) 0.112 0.025 110 9.17 0.63 0.137 ( 0.542) 0.112 0.025 111 9.25 0.63 0.137 ( 0.539) 0.112 0.025 112 9.33 0.67 0.144 ( 0.537) 0.118 0.026 113 9.42 0.67 0.144 ( 0.534) 0.118 0.026 114 9.50 0.67 0.144 ( 0.531) 0.118 0.026 115 9.58 0.70 0.151 ( 0.529) 0.124 0.027 116 9.67 0.70 0.151 ( 0.526) 0.124 0.027 117 9.75 0.70 0.151 ( 0.524) 0.124 0.027 118 9.83 0.73 0.158 ( 0.521) 0.130 0.029 119 9.92 0.73 0.158 ( 0.519) 0.130 0.029 120 10.00 0.73 0.158 ( 0.516) 0.130 0.029 121 10.08 0.50 0.108 ( 0.514) 0.089 0.019 122 10.17 0.50 0.108 ( 0.511) 0.089 0.019 123 10.25 0.50 0.108 ( 0.509) 0.089 0.019 124 10.33 0.50 0.108 ( 0.506) 0.089 0.019 125 10.42 0.50 0.108 ( 0.504) 0.089 0.019 126 10.50 0.50 0.108 ( 0.501) 0.089 0.019 127 10.58 0.67 0.144 ( 0.499) 0.118 0.026 128 10.67 0.67 0.144 ( 0.497) 0.118 0.026 129 10.75 0.67 0.144 ( 0.494) 0.118 0.026 130 10.83 0.67 0.144 ( 0.492) 0.118 0.026 131 10.92 0.67 0.144 ( 0.489) 0.118 0.026 132 11.00 0.67 0.144 ( 0.487) 0.118 0.026 133 11.08 0.63 0.137 ( 0.485) 0.112 0.025 134 11.17 0.63 0.137 ( 0.482) 0.112 0.025 135 11.25 0.63 0.137 ( 0.480) 0.112 0.025 136 11.33 0.63 0.137 ( 0.477) 0.112 0.025 137 11.42 0.63 0.137 ( 0.475) 0.112 0.025 138 11.50 0.63 0.137 ( 0.473) 0.112 0.025 139 11.58 0.57 0.122 ( 0.470) 0.100 0.022 140 11.67 0.57 0.122 ( 0.468) 0.100 0.022 141 11.75 0.57 0.122 ( 0.466) 0.100 0.022 142 11.83 0.60 0.130 ( 0.463) 0.106 0.023 143 11.92 0.60 0.130 ( 0.461) 0.106 0.023 144 12.00 0.60 0.130 ( 0.459) 0.106 0.023 145 12.08 0.83 0.180 ( 0.456) 0.148 0.032 146 12.17 0.83 0.180 ( 0.454) 0.148 0.032 147 12.25 0.83 0.180 ( 0.452) 0.148 0.032 148 12.33 0.87 0.187 ( 0.450) 0.154 0.034 149 12.42 0.87 0.187 ( 0.447) 0.154 0.034 150 12.50 0.87 0.187 ( 0.445) 0.154 0.034 151 12.58 0.93 0.202 ( 0.443) 0.165 0.036 152 12.67 0.93 0.202 ( 0.441) 0.165 0.036 153 12.75 0.93 0.202 ( 0.438) 0.165 0.036 154 12.83 0.97 0.209 ( 0.436) 0.171 0.038 155 12.92 0.97 0.209 ( 0.434) 0.171 0.038 156 13.00 0.97 0.209 ( 0.432) 0.171 0.038 157 13.08 1.13 0.245 ( 0.430) 0.201 0.044 158 13.17 1.13 0.245 ( 0.427) 0.201 0.044 PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies EX2YR24HR Page 4 of 9
159 13.25 1.13 0.245 ( 0.425) 0.201 0.044 160 13.33 1.13 0.245 ( 0.423) 0.201 0.044 161 13.42 1.13 0.245 ( 0.421) 0.201 0.044 162 13.50 1.13 0.245 ( 0.419) 0.201 0.044 163 13.58 0.77 0.166 ( 0.417) 0.136 0.030 164 13.67 0.77 0.166 ( 0.415) 0.136 0.030 165 13.75 0.77 0.166 ( 0.412) 0.136 0.030 166 13.83 0.77 0.166 ( 0.410) 0.136 0.030 167 13.92 0.77 0.166 ( 0.408) 0.136 0.030 168 14.00 0.77 0.166 ( 0.406) 0.136 0.030 169 14.08 0.90 0.194 ( 0.404) 0.159 0.035 170 14.17 0.90 0.194 ( 0.402) 0.159 0.035 171 14.25 0.90 0.194 ( 0.400) 0.159 0.035 172 14.33 0.87 0.187 ( 0.398) 0.154 0.034 173 14.42 0.87 0.187 ( 0.396) 0.154 0.034 174 14.50 0.87 0.187 ( 0.394) 0.154 0.034 175 14.58 0.87 0.187 ( 0.392) 0.154 0.034 176 14.67 0.87 0.187 ( 0.390) 0.154 0.034 177 14.75 0.87 0.187 ( 0.388) 0.154 0.034 178 14.83 0.83 0.180 ( 0.386) 0.148 0.032 179 14.92 0.83 0.180 ( 0.384) 0.148 0.032 180 15.00 0.83 0.180 ( 0.382) 0.148 0.032 181 15.08 0.80 0.173 ( 0.380) 0.142 0.031 182 15.17 0.80 0.173 ( 0.378) 0.142 0.031 183 15.25 0.80 0.173 ( 0.376) 0.142 0.031 184 15.33 0.77 0.166 ( 0.374) 0.136 0.030 185 15.42 0.77 0.166 ( 0.372) 0.136 0.030 186 15.50 0.77 0.166 ( 0.370) 0.136 0.030 187 15.58 0.63 0.137 ( 0.368) 0.112 0.025 188 15.67 0.63 0.137 ( 0.367) 0.112 0.025 189 15.75 0.63 0.137 ( 0.365) 0.112 0.025 190 15.83 0.63 0.137 ( 0.363) 0.112 0.025 191 15.92 0.63 0.137 ( 0.361) 0.112 0.025 192 16.00 0.63 0.137 ( 0.359) 0.112 0.025 193 16.08 0.13 0.029 ( 0.357) 0.024 0.005 194 16.17 0.13 0.029 ( 0.355) 0.024 0.005 195 16.25 0.13 0.029 ( 0.354) 0.024 0.005 196 16.33 0.13 0.029 ( 0.352) 0.024 0.005 197 16.42 0.13 0.029 ( 0.350) 0.024 0.005 198 16.50 0.13 0.029 ( 0.348) 0.024 0.005 199 16.58 0.10 0.022 ( 0.346) 0.018 0.004 200 16.67 0.10 0.022 ( 0.345) 0.018 0.004 201 16.75 0.10 0.022 ( 0.343) 0.018 0.004 202 16.83 0.10 0.022 ( 0.341) 0.018 0.004 203 16.92 0.10 0.022 ( 0.339) 0.018 0.004 204 17.00 0.10 0.022 ( 0.338) 0.018 0.004 205 17.08 0.17 0.036 ( 0.336) 0.030 0.006 206 17.17 0.17 0.036 ( 0.334) 0.030 0.006 207 17.25 0.17 0.036 ( 0.333) 0.030 0.006 208 17.33 0.17 0.036 ( 0.331) 0.030 0.006 209 17.42 0.17 0.036 ( 0.329) 0.030 0.006 210 17.50 0.17 0.036 ( 0.328) 0.030 0.006 211 17.58 0.17 0.036 ( 0.326) 0.030 0.006 212 17.67 0.17 0.036 ( 0.324) 0.030 0.006 213 17.75 0.17 0.036 ( 0.323) 0.030 0.006 214 17.83 0.13 0.029 ( 0.321) 0.024 0.005 215 17.92 0.13 0.029 ( 0.320) 0.024 0.005 216 18.00 0.13 0.029 ( 0.318) 0.024 0.005 217 18.08 0.13 0.029 ( 0.316) 0.024 0.005 218 18.17 0.13 0.029 ( 0.315) 0.024 0.005 219 18.25 0.13 0.029 ( 0.313) 0.024 0.005 220 18.33 0.13 0.029 ( 0.312) 0.024 0.005 221 18.42 0.13 0.029 ( 0.310) 0.024 0.005 222 18.50 0.13 0.029 ( 0.309) 0.024 0.005 223 18.58 0.10 0.022 ( 0.307) 0.018 0.004 224 18.67 0.10 0.022 ( 0.306) 0.018 0.004 225 18.75 0.10 0.022 ( 0.304) 0.018 0.004 226 18.83 0.07 0.014 ( 0.303) 0.012 0.003 227 18.92 0.07 0.014 ( 0.301) 0.012 0.003 228 19.00 0.07 0.014 ( 0.300) 0.012 0.003 229 19.08 0.10 0.022 ( 0.299) 0.018 0.004 230 19.17 0.10 0.022 ( 0.297) 0.018 0.004 231 19.25 0.10 0.022 ( 0.296) 0.018 0.004 232 19.33 0.13 0.029 ( 0.294) 0.024 0.005 233 19.42 0.13 0.029 ( 0.293) 0.024 0.005 234 19.50 0.13 0.029 ( 0.292) 0.024 0.005 235 19.58 0.10 0.022 ( 0.290) 0.018 0.004 236 19.67 0.10 0.022 ( 0.289) 0.018 0.004 237 19.75 0.10 0.022 ( 0.288) 0.018 0.004 238 19.83 0.07 0.014 ( 0.286) 0.012 0.003 239 19.92 0.07 0.014 ( 0.285) 0.012 0.003 240 20.00 0.07 0.014 ( 0.284) 0.012 0.003 241 20.08 0.10 0.022 ( 0.283) 0.018 0.004 242 20.17 0.10 0.022 ( 0.281) 0.018 0.004 243 20.25 0.10 0.022 ( 0.280) 0.018 0.004 244 20.33 0.10 0.022 ( 0.279) 0.018 0.004 PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies EX2YR24HR Page 5 of 9
245 20.42 0.10 0.022 ( 0.278) 0.018 0.004 246 20.50 0.10 0.022 ( 0.277) 0.018 0.004 247 20.58 0.10 0.022 ( 0.275) 0.018 0.004 248 20.67 0.10 0.022 ( 0.274) 0.018 0.004 249 20.75 0.10 0.022 ( 0.273) 0.018 0.004 250 20.83 0.07 0.014 ( 0.272) 0.012 0.003 251 20.92 0.07 0.014 ( 0.271) 0.012 0.003 252 21.00 0.07 0.014 ( 0.270) 0.012 0.003 253 21.08 0.10 0.022 ( 0.269) 0.018 0.004 254 21.17 0.10 0.022 ( 0.268) 0.018 0.004 255 21.25 0.10 0.022 ( 0.267) 0.018 0.004 256 21.33 0.07 0.014 ( 0.266) 0.012 0.003 257 21.42 0.07 0.014 ( 0.265) 0.012 0.003 258 21.50 0.07 0.014 ( 0.264) 0.012 0.003 259 21.58 0.10 0.022 ( 0.263) 0.018 0.004 260 21.67 0.10 0.022 ( 0.262) 0.018 0.004 261 21.75 0.10 0.022 ( 0.261) 0.018 0.004 262 21.83 0.07 0.014 ( 0.260) 0.012 0.003 263 21.92 0.07 0.014 ( 0.259) 0.012 0.003 264 22.00 0.07 0.014 ( 0.258) 0.012 0.003 265 22.08 0.10 0.022 ( 0.257) 0.018 0.004 266 22.17 0.10 0.022 ( 0.256) 0.018 0.004 267 22.25 0.10 0.022 ( 0.256) 0.018 0.004 268 22.33 0.07 0.014 ( 0.255) 0.012 0.003 269 22.42 0.07 0.014 ( 0.254) 0.012 0.003 270 22.50 0.07 0.014 ( 0.253) 0.012 0.003 271 22.58 0.07 0.014 ( 0.253) 0.012 0.003 272 22.67 0.07 0.014 ( 0.252) 0.012 0.003 273 22.75 0.07 0.014 ( 0.251) 0.012 0.003 274 22.83 0.07 0.014 ( 0.251) 0.012 0.003 275 22.92 0.07 0.014 ( 0.250) 0.012 0.003 276 23.00 0.07 0.014 ( 0.249) 0.012 0.003 277 23.08 0.07 0.014 ( 0.249) 0.012 0.003 278 23.17 0.07 0.014 ( 0.248) 0.012 0.003 279 23.25 0.07 0.014 ( 0.248) 0.012 0.003 280 23.33 0.07 0.014 ( 0.247) 0.012 0.003 281 23.42 0.07 0.014 ( 0.247) 0.012 0.003 282 23.50 0.07 0.014 ( 0.246) 0.012 0.003 283 23.58 0.07 0.014 ( 0.246) 0.012 0.003 284 23.67 0.07 0.014 ( 0.245) 0.012 0.003 285 23.75 0.07 0.014 ( 0.245) 0.012 0.003 286 23.83 0.07 0.014 ( 0.245) 0.012 0.003 287 23.92 0.07 0.014 ( 0.245) 0.012 0.003 288 24.00 0.07 0.014 ( 0.245) 0.012 0.003 (Loss Rate Not Used)
Sum = 100.0 Sum = 3.9 Flood volume = Effective rainfall 0.32(In)
times area 7.0(Ac.)/[(In)/(Ft.)] = 0.2(Ac.Ft) Total soil loss = 1.48(In)
Total soil loss = 0.861(Ac.Ft)
Total rainfall = 1.80(In)
Flood volume = 8232.7 Cubic Feet
Total soil loss = 37504.6 Cubic Feet
-------------------------------------------------------------------- Peak flow rate of this hydrograph = 0.311(CFS)
-------------------------------------------------------------------- ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 24 - H O U R S T O R M
R u n o f f H y d r o g r a p h
-------------------------------------------------------------------- Hydrograph in 5 Minute intervals ((CFS))
-------------------------------------------------------------------- Time(h+m) Volume Ac.Ft Q(CFS) 0 2.5 5.0 7.5 10.0 ----------------------------------------------------------------------- 0+ 5 0.0001 0.01 Q | | | | 0+10 0.0002 0.02 Q | | | | 0+15 0.0003 0.02 Q | | | | 0+20 0.0004 0.02 Q | | | | 0+25 0.0006 0.03 Q | | | | 0+30 0.0008 0.03 Q | | | | 0+35 0.0010 0.03 Q | | | | 0+40 0.0012 0.03 Q | | | | 0+45 0.0014 0.03 Q | | | | 0+50 0.0016 0.03 Q | | | | 0+55 0.0018 0.04 Q | | | | 1+ 0 0.0021 0.04 Q | | | | 1+ 5 0.0023 0.03 Q | | | | 1+10 0.0025 0.03 Q | | | | 1+15 0.0027 0.03 Q | | | | 1+20 0.0029 0.03 Q | | | | 1+25 0.0031 0.03 Q | | | | 1+30 0.0033 0.03 Q | | | | 1+35 0.0035 0.03 Q | | | | 1+40 0.0037 0.03 Q | | | | 1+45 0.0038 0.03 Q | | | | PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies EX2YR24HR Page 6 of 9
1+50 0.0041 0.03 Q | | | | 1+55 0.0043 0.04 Q | | | | 2+ 0 0.0046 0.04 Q | | | | 2+ 5 0.0048 0.04 QV | | | | 2+10 0.0051 0.04 QV | | | | 2+15 0.0053 0.04 QV | | | | 2+20 0.0056 0.04 QV | | | | 2+25 0.0058 0.04 QV | | | | 2+30 0.0061 0.04 QV | | | | 2+35 0.0063 0.04 QV | | | | 2+40 0.0067 0.04 QV | | | | 2+45 0.0070 0.05 QV | | | | 2+50 0.0073 0.05 QV | | | | 2+55 0.0076 0.05 QV | | | | 3+ 0 0.0079 0.05 QV | | | | 3+ 5 0.0082 0.05 QV | | | | 3+10 0.0085 0.05 QV | | | | 3+15 0.0089 0.05 QV | | | | 3+20 0.0092 0.05 QV | | | | 3+25 0.0095 0.05 Q V | | | | 3+30 0.0098 0.05 Q V | | | | 3+35 0.0101 0.05 Q V | | | | 3+40 0.0104 0.05 Q V | | | | 3+45 0.0107 0.05 Q V | | | | 3+50 0.0111 0.05 Q V | | | | 3+55 0.0115 0.05 Q V | | | | 4+ 0 0.0118 0.05 Q V | | | | 4+ 5 0.0122 0.05 Q V | | | | 4+10 0.0126 0.05 Q V | | | | 4+15 0.0130 0.05 Q V | | | | 4+20 0.0134 0.06 Q V | | | | 4+25 0.0138 0.06 Q V | | | | 4+30 0.0143 0.06 Q V | | | | 4+35 0.0147 0.06 Q V | | | | 4+40 0.0151 0.06 Q V | | | | 4+45 0.0156 0.06 Q V | | | | 4+50 0.0160 0.07 Q V | | | | 4+55 0.0165 0.07 Q V | | | | 5+ 0 0.0170 0.07 Q V | | | | 5+ 5 0.0175 0.06 Q V | | | | 5+10 0.0179 0.06 Q V | | | | 5+15 0.0183 0.06 Q V | | | | 5+20 0.0187 0.06 Q V | | | | 5+25 0.0191 0.06 Q V | | | | 5+30 0.0195 0.06 Q V | | | | 5+35 0.0200 0.07 Q V | | | | 5+40 0.0205 0.07 Q V | | | | 5+45 0.0210 0.07 Q V | | | | 5+50 0.0215 0.07 Q V | | | | 5+55 0.0220 0.07 Q V | | | | 6+ 0 0.0225 0.07 Q V | | | | 6+ 5 0.0231 0.08 Q V | | | | 6+10 0.0236 0.08 Q V | | | | 6+15 0.0242 0.08 Q V | | | | 6+20 0.0248 0.08 Q V | | | | 6+25 0.0253 0.08 Q V | | | | 6+30 0.0259 0.08 Q V | | | | 6+35 0.0265 0.09 Q V | | | | 6+40 0.0271 0.09 Q V | | | | 6+45 0.0277 0.09 Q V | | | | 6+50 0.0284 0.09 Q V | | | | 6+55 0.0290 0.09 Q V | | | | 7+ 0 0.0296 0.09 Q V | | | | 7+ 5 0.0303 0.09 Q V | | | | 7+10 0.0309 0.09 Q V | | | | 7+15 0.0315 0.09 Q V | | | | 7+20 0.0322 0.10 Q V | | | | 7+25 0.0329 0.10 Q V | | | | 7+30 0.0336 0.10 Q V | | | | 7+35 0.0343 0.10 Q V | | | | 7+40 0.0350 0.11 Q V | | | | 7+45 0.0358 0.11 Q V | | | | 7+50 0.0366 0.11 Q V | | | | 7+55 0.0374 0.12 Q V | | | | 8+ 0 0.0382 0.12 Q V | | | | 8+ 5 0.0391 0.13 Q V | | | | 8+10 0.0400 0.14 Q V | | | | 8+15 0.0409 0.14 Q V | | | | 8+20 0.0419 0.14 Q V | | | | 8+25 0.0428 0.14 Q V| | | | 8+30 0.0438 0.14 Q V| | | | 8+35 0.0448 0.14 Q V| | | | 8+40 0.0458 0.15 Q V| | | | 8+45 0.0468 0.15 Q V| | | | 8+50 0.0478 0.15 Q V | | | 8+55 0.0489 0.15 Q V | | | PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies EX2YR24HR Page 7 of 9
9+ 0 0.0499 0.16 Q V | | | 9+ 5 0.0511 0.16 Q V | | | 9+10 0.0522 0.17 Q |V | | | 9+15 0.0534 0.17 Q |V | | | 9+20 0.0547 0.18 Q |V | | | 9+25 0.0559 0.18 Q |V | | | 9+30 0.0572 0.18 Q | V | | | 9+35 0.0585 0.19 Q | V | | | 9+40 0.0598 0.19 Q | V | | | 9+45 0.0611 0.19 Q | V | | | 9+50 0.0625 0.20 Q | V | | | 9+55 0.0638 0.20 Q | V | | | 10+ 0 0.0652 0.20 Q | V | | | 10+ 5 0.0664 0.17 Q | V | | | 10+10 0.0674 0.14 Q | V | | | 10+15 0.0683 0.14 Q | V | | | 10+20 0.0693 0.14 Q | V | | | 10+25 0.0702 0.14 Q | V | | | 10+30 0.0712 0.14 Q | V | | | 10+35 0.0723 0.16 Q | V | | | 10+40 0.0735 0.18 Q | V | | | 10+45 0.0747 0.18 Q | V | | | 10+50 0.0760 0.18 Q | V | | | 10+55 0.0773 0.18 Q | V | | | 11+ 0 0.0785 0.18 Q | V | | | 11+ 5 0.0798 0.18 Q | V | | | 11+10 0.0810 0.17 Q | V | | | 11+15 0.0822 0.17 Q | V | | | 11+20 0.0834 0.17 Q | V | | | 11+25 0.0846 0.17 Q | V | | | 11+30 0.0858 0.17 Q | V | | | 11+35 0.0869 0.17 Q | V | | | 11+40 0.0880 0.16 Q | V | | | 11+45 0.0891 0.16 Q | V | | | 11+50 0.0902 0.16 Q | V| | | 11+55 0.0913 0.16 Q | V| | | 12+ 0 0.0924 0.16 Q | V| | | 12+ 5 0.0938 0.19 Q | V| | | 12+10 0.0953 0.22 Q | V | | 12+15 0.0968 0.23 Q | V | | 12+20 0.0984 0.23 Q | V | | 12+25 0.1001 0.24 Q | |V | | 12+30 0.1017 0.24 Q | |V | | 12+35 0.1034 0.25 Q | |V | | 12+40 0.1052 0.25 |Q | | V | | 12+45 0.1069 0.26 |Q | | V | | 12+50 0.1087 0.26 |Q | | V | | 12+55 0.1105 0.26 |Q | | V | | 13+ 0 0.1124 0.26 |Q | | V | | 13+ 5 0.1143 0.29 |Q | | V | | 13+10 0.1164 0.31 |Q | | V | | 13+15 0.1186 0.31 |Q | | V | | 13+20 0.1207 0.31 |Q | | V | | 13+25 0.1229 0.31 |Q | | V | | 13+30 0.1250 0.31 |Q | | V | | 13+35 0.1268 0.26 |Q | | V | | 13+40 0.1283 0.22 Q | | V | | 13+45 0.1298 0.21 Q | | V | | 13+50 0.1313 0.21 Q | | V | | 13+55 0.1327 0.21 Q | | V | | 14+ 0 0.1342 0.21 Q | | V | | 14+ 5 0.1357 0.23 Q | | V | | 14+10 0.1374 0.24 Q | | V| | 14+15 0.1391 0.25 Q | | V| | 14+20 0.1408 0.24 Q | | V| | 14+25 0.1424 0.24 Q | | V | 14+30 0.1440 0.24 Q | | V | 14+35 0.1457 0.24 Q | | V | 14+40 0.1473 0.24 Q | | |V | 14+45 0.1490 0.24 Q | | |V | 14+50 0.1506 0.23 Q | | |V | 14+55 0.1521 0.23 Q | | | V | 15+ 0 0.1537 0.23 Q | | | V | 15+ 5 0.1553 0.22 Q | | | V | 15+10 0.1568 0.22 Q | | | V | 15+15 0.1583 0.22 Q | | | V | 15+20 0.1598 0.22 Q | | | V | 15+25 0.1612 0.21 Q | | | V | 15+30 0.1627 0.21 Q | | | V | 15+35 0.1640 0.19 Q | | | V | 15+40 0.1652 0.18 Q | | | V | 15+45 0.1665 0.17 Q | | | V | 15+50 0.1677 0.17 Q | | | V | 15+55 0.1688 0.17 Q | | | V | 16+ 0 0.1700 0.17 Q | | | V | 16+ 5 0.1708 0.11 Q | | | V | PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies EX2YR24HR Page 8 of 9
16+10 0.1712 0.05 Q | | | V | 16+15 0.1714 0.04 Q | | | V | 16+20 0.1717 0.04 Q | | | V | 16+25 0.1719 0.04 Q | | | V | 16+30 0.1722 0.04 Q | | | V | 16+35 0.1724 0.03 Q | | | V | 16+40 0.1726 0.03 Q | | | V | 16+45 0.1728 0.03 Q | | | V | 16+50 0.1730 0.03 Q | | | V | 16+55 0.1732 0.03 Q | | | V | 17+ 0 0.1734 0.03 Q | | | V | 17+ 5 0.1736 0.04 Q | | | V | 17+10 0.1739 0.04 Q | | | V | 17+15 0.1742 0.05 Q | | | V | 17+20 0.1745 0.05 Q | | | V | 17+25 0.1749 0.05 Q | | | V | 17+30 0.1752 0.05 Q | | | V | 17+35 0.1755 0.05 Q | | | V | 17+40 0.1758 0.05 Q | | | V | 17+45 0.1761 0.05 Q | | | V | 17+50 0.1764 0.04 Q | | | V | 17+55 0.1767 0.04 Q | | | V | 18+ 0 0.1769 0.04 Q | | | V | 18+ 5 0.1772 0.04 Q | | | V | 18+10 0.1774 0.04 Q | | | V | 18+15 0.1777 0.04 Q | | | V | 18+20 0.1779 0.04 Q | | | V | 18+25 0.1782 0.04 Q | | | V | 18+30 0.1784 0.04 Q | | | V | 18+35 0.1787 0.03 Q | | | V | 18+40 0.1789 0.03 Q | | | V | 18+45 0.1790 0.03 Q | | | V | 18+50 0.1792 0.02 Q | | | V | 18+55 0.1793 0.02 Q | | | V | 19+ 0 0.1795 0.02 Q | | | V | 19+ 5 0.1796 0.02 Q | | | V | 19+10 0.1798 0.03 Q | | | V | 19+15 0.1800 0.03 Q | | | V | 19+20 0.1802 0.03 Q | | | V | 19+25 0.1805 0.04 Q | | | V | 19+30 0.1807 0.04 Q | | | V | 19+35 0.1809 0.03 Q | | | V | 19+40 0.1811 0.03 Q | | | V | 19+45 0.1813 0.03 Q | | | V | 19+50 0.1815 0.02 Q | | | V | 19+55 0.1816 0.02 Q | | | V | 20+ 0 0.1817 0.02 Q | | | V | 20+ 5 0.1819 0.02 Q | | | V | 20+10 0.1821 0.03 Q | | | V | 20+15 0.1823 0.03 Q | | | V | 20+20 0.1824 0.03 Q | | | V | 20+25 0.1826 0.03 Q | | | V | 20+30 0.1828 0.03 Q | | | V | 20+35 0.1830 0.03 Q | | | V | 20+40 0.1832 0.03 Q | | | V | 20+45 0.1834 0.03 Q | | | V | 20+50 0.1835 0.02 Q | | | V | 20+55 0.1837 0.02 Q | | | V | 21+ 0 0.1838 0.02 Q | | | V | 21+ 5 0.1840 0.02 Q | | | V | 21+10 0.1841 0.03 Q | | | V | 21+15 0.1843 0.03 Q | | | V| 21+20 0.1845 0.02 Q | | | V| 21+25 0.1846 0.02 Q | | | V| 21+30 0.1848 0.02 Q | | | V| 21+35 0.1849 0.02 Q | | | V| 21+40 0.1851 0.03 Q | | | V| 21+45 0.1853 0.03 Q | | | V| 21+50 0.1854 0.02 Q | | | V| 21+55 0.1856 0.02 Q | | | V| 22+ 0 0.1857 0.02 Q | | | V| 22+ 5 0.1859 0.02 Q | | | V| 22+10 0.1860 0.03 Q | | | V| 22+15 0.1862 0.03 Q | | | V| 22+20 0.1864 0.02 Q | | | V| 22+25 0.1865 0.02 Q | | | V| 22+30 0.1866 0.02 Q | | | V| 22+35 0.1868 0.02 Q | | | V| 22+40 0.1869 0.02 Q | | | V| 22+45 0.1870 0.02 Q | | | V| 22+50 0.1871 0.02 Q | | | V| 22+55 0.1873 0.02 Q | | | V| 23+ 0 0.1874 0.02 Q | | | V| 23+ 5 0.1875 0.02 Q | | | V| 23+10 0.1877 0.02 Q | | | V| 23+15 0.1878 0.02 Q | | | V| PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies EX2YR24HR Page 9 of 9
23+20 0.1879 0.02 Q | | | V| 23+25 0.1880 0.02 Q | | | V| 23+30 0.1882 0.02 Q | | | V| 23+35 0.1883 0.02 Q | | | V| 23+40 0.1884 0.02 Q | | | V| 23+45 0.1885 0.02 Q | | | V| 23+50 0.1887 0.02 Q | | | V| 23+55 0.1888 0.02 Q | | | V| 24+ 0 0.1889 0.02 Q | | | V| 24+ 5 0.1890 0.01 Q | | | V| 24+10 0.1890 0.00 Q | | | V| 24+15 0.1890 0.00 Q | | | V| ----------------------------------------------------------------------- PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies PRO 2YR24HR Page 1 of 9
U n i t H y d r o g r a p h A n a l y s i s
Copyright (c) CIVILCADD/CIVILDESIGN, 1989 - 2008, Version 8.1 Study date 02/22/24 File: 2YR242.out
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ ------------------------------------------------------------------------ Riverside County Synthetic Unit Hydrology Method
RCFC & WCD Manual date - April 1978
Program License Serial Number 5006
--------------------------------------------------------------------- English (in-lb) Input Units Used
English Rainfall Data (Inches) Input Values Used
English Units used in output format
--------------------------------------------------------------------- -------------------------------------------------------------------- Drainage Area = 7.00(Ac.) = 0.011 Sq. Mi.

Drainage Area for Depth-Area Areal Adjustment = 7.00(Ac.) = 0.011 Sq. Mi.

Length along longest watercourse = 861.00(Ft.)
Length along longest watercourse measured to centroid = 430.00(Ft.) Length along longest watercourse = 0.163 Mi.

Length along longest watercourse measured to centroid = 0.081 Mi.

Difference in elevation = 16.90(Ft.)
Slope along watercourse = 103.6376 Ft./Mi.

Average Manning's 'N' = 0.015
Lag time = 0.029 Hr.

Lag time = 1.73 Min.
25% of lag time = 0.43 Min.
40% of lag time = 0.69 Min.

Unit time = 5.00 Min.

Duration of storm = 24 Hour(s)
User Entered Base Flow = 0.00(CFS)
2 YEAR Area rainfall data:

Area(Ac.)[1] Rainfall(In)[2] Weighting[1*2]

7.00 1.80 12.60
100 YEAR Area rainfall data:

Area(Ac.)[1] Rainfall(In)[2] Weighting[1*2]

Area(Ac.) Runoff Index Impervious %

7.000 69.00 0.600
Total Area Entered = 7.00(Ac.)
RI RI Infil. Rate Impervious Adj. Infil. Rate Area% F AMC2 AMC-1 (In/Hr) (Dec.%) (In/Hr) (Dec.) (In/Hr)

69.0 49.8 0.574 0.600 0.264 1.000 0.264 Sum (F) = 0.264
Area averaged mean soil loss (F) (In/Hr) = 0.264
Minimum soil loss rate ((In/Hr)) = 0.132
(for 24 hour storm duration)
Soil low loss rate (decimal) = 0.420
--------------------------------------------------------------------- U n i t H y d r o g r a p h
VALLEY S-Curve
-------------------------------------------------------------------- Unit Hydrograph Data
--------------------------------------------------------------------- Unit time period Time % of lag Distribution Unit Hydrograph (hrs) Graph % (CFS) PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies PRO 2YR24HR Page 2 of 9
--------------------------------------------------------------------- 1 0.083 288.833 55.504 3.916 2 0.167 577.666 37.752 2.663 3 0.250 866.500 6.744 0.476 Sum = 100.000 Sum= 7.055
----------------------------------------------------------------------- The following loss rate calculations reflect use of the minimum calculated loss rate subtracted from the Storm Rain to produce the maximum Effective Rain value Unit Time Pattern Storm Rain Loss rate(In./Hr) Effective (Hr.) Percent (In/Hr) Max | Low (In/Hr) 1 0.08 0.07 0.014 ( 0.468) 0.006 0.008 2 0.17 0.07 0.014 ( 0.466) 0.006 0.008 3 0.25 0.07 0.014 ( 0.464) 0.006 0.008 4 0.33 0.10 0.022 ( 0.463) 0.009 0.013 5 0.42 0.10 0.022 ( 0.461) 0.009 0.013 6 0.50 0.10 0.022 ( 0.459) 0.009 0.013 7 0.58 0.10 0.022 ( 0.457) 0.009 0.013 8 0.67 0.10 0.022 ( 0.455) 0.009 0.013 9 0.75 0.10 0.022 ( 0.454) 0.009 0.013 10 0.83 0.13 0.029 ( 0.452) 0.012 0.017 11 0.92 0.13 0.029 ( 0.450) 0.012 0.017 12 1.00 0.13 0.029 ( 0.448) 0.012 0.017 13 1.08 0.10 0.022 ( 0.447) 0.009 0.013 14 1.17 0.10 0.022 ( 0.445) 0.009 0.013 15 1.25 0.10 0.022 ( 0.443) 0.009 0.013 16 1.33 0.10 0.022 ( 0.441) 0.009 0.013 17 1.42 0.10 0.022 ( 0.439) 0.009 0.013 18 1.50 0.10 0.022 ( 0.438) 0.009 0.013 19 1.58 0.10 0.022 ( 0.436) 0.009 0.013 20 1.67 0.10 0.022 ( 0.434) 0.009 0.013 21 1.75 0.10 0.022 ( 0.433) 0.009 0.013 22 1.83 0.13 0.029 ( 0.431) 0.012 0.017 23 1.92 0.13 0.029 ( 0.429) 0.012 0.017 24 2.00 0.13 0.029 ( 0.427) 0.012 0.017 25 2.08 0.13 0.029 ( 0.426) 0.012 0.017 26 2.17 0.13 0.029 ( 0.424) 0.012 0.017 27 2.25 0.13 0.029 ( 0.422) 0.012 0.017 28 2.33 0.13 0.029 ( 0.420) 0.012 0.017 29 2.42 0.13 0.029 ( 0.419) 0.012 0.017 30 2.50 0.13 0.029 ( 0.417) 0.012 0.017 31 2.58 0.17 0.036 ( 0.415) 0.015 0.021 32 2.67 0.17 0.036 ( 0.414) 0.015 0.021 33 2.75 0.17 0.036 ( 0.412) 0.015 0.021 34 2.83 0.17 0.036 ( 0.410) 0.015 0.021 35 2.92 0.17 0.036 ( 0.408) 0.015 0.021 36 3.00 0.17 0.036 ( 0.407) 0.015 0.021 37 3.08 0.17 0.036 ( 0.405) 0.015 0.021 38 3.17 0.17 0.036 ( 0.403) 0.015 0.021 39 3.25 0.17 0.036 ( 0.402) 0.015 0.021 40 3.33 0.17 0.036 ( 0.400) 0.015 0.021 41 3.42 0.17 0.036 ( 0.398) 0.015 0.021 42 3.50 0.17 0.036 ( 0.397) 0.015 0.021 43 3.58 0.17 0.036 ( 0.395) 0.015 0.021 44 3.67 0.17 0.036 ( 0.393) 0.015 0.021 45 3.75 0.17 0.036 ( 0.392) 0.015 0.021 46 3.83 0.20 0.043 ( 0.390) 0.018 0.025 47 3.92 0.20 0.043 ( 0.388) 0.018 0.025 48 4.00 0.20 0.043 ( 0.387) 0.018 0.025 49 4.08 0.20 0.043 ( 0.385) 0.018 0.025 50 4.17 0.20 0.043 ( 0.384) 0.018 0.025 51 4.25 0.20 0.043 ( 0.382) 0.018 0.025 52 4.33 0.23 0.050 ( 0.380) 0.021 0.029 53 4.42 0.23 0.050 ( 0.379) 0.021 0.029 54 4.50 0.23 0.050 ( 0.377) 0.021 0.029 55 4.58 0.23 0.050 ( 0.375) 0.021 0.029 56 4.67 0.23 0.050 ( 0.374) 0.021 0.029 57 4.75 0.23 0.050 ( 0.372) 0.021 0.029 58 4.83 0.27 0.058 ( 0.371) 0.024 0.033 59 4.92 0.27 0.058 ( 0.369) 0.024 0.033 60 5.00 0.27 0.058 ( 0.367) 0.024 0.033 61 5.08 0.20 0.043 ( 0.366) 0.018 0.025 62 5.17 0.20 0.043 ( 0.364) 0.018 0.025 63 5.25 0.20 0.043 ( 0.363) 0.018 0.025 64 5.33 0.23 0.050 ( 0.361) 0.021 0.029 65 5.42 0.23 0.050 ( 0.359) 0.021 0.029 66 5.50 0.23 0.050 ( 0.358) 0.021 0.029 67 5.58 0.27 0.058 ( 0.356) 0.024 0.033 68 5.67 0.27 0.058 ( 0.355) 0.024 0.033 69 5.75 0.27 0.058 ( 0.353) 0.024 0.033 70 5.83 0.27 0.058 ( 0.352) 0.024 0.033 71 5.92 0.27 0.058 ( 0.350) 0.024 0.033 72 6.00 0.27 0.058 ( 0.349) 0.024 0.033 73 6.08 0.30 0.065 ( 0.347) 0.027 0.038 PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies PRO 2YR24HR Page 3 of 9
74 6.17 0.30 0.065 ( 0.345) 0.027 0.038 75 6.25 0.30 0.065 ( 0.344) 0.027 0.038 76 6.33 0.30 0.065 ( 0.342) 0.027 0.038 77 6.42 0.30 0.065 ( 0.341) 0.027 0.038 78 6.50 0.30 0.065 ( 0.339) 0.027 0.038 79 6.58 0.33 0.072 ( 0.338) 0.030 0.042 80 6.67 0.33 0.072 ( 0.336) 0.030 0.042 81 6.75 0.33 0.072 ( 0.335) 0.030 0.042 82 6.83 0.33 0.072 ( 0.333) 0.030 0.042 83 6.92 0.33 0.072 ( 0.332) 0.030 0.042 84 7.00 0.33 0.072 ( 0.330) 0.030 0.042 85 7.08 0.33 0.072 ( 0.329) 0.030 0.042 86 7.17 0.33 0.072 ( 0.327) 0.030 0.042 87 7.25 0.33 0.072 ( 0.326) 0.030 0.042 88 7.33 0.37 0.079 ( 0.324) 0.033 0.046 89 7.42 0.37 0.079 ( 0.323) 0.033 0.046 90 7.50 0.37 0.079 ( 0.321) 0.033 0.046 91 7.58 0.40 0.086 ( 0.320) 0.036 0.050 92 7.67 0.40 0.086 ( 0.318) 0.036 0.050 93 7.75 0.40 0.086 ( 0.317) 0.036 0.050 94 7.83 0.43 0.094 ( 0.315) 0.039 0.054 95 7.92 0.43 0.094 ( 0.314) 0.039 0.054 96 8.00 0.43 0.094 ( 0.312) 0.039 0.054 97 8.08 0.50 0.108 ( 0.311) 0.045 0.063 98 8.17 0.50 0.108 ( 0.310) 0.045 0.063 99 8.25 0.50 0.108 ( 0.308) 0.045 0.063 100 8.33 0.50 0.108 ( 0.307) 0.045 0.063 101 8.42 0.50 0.108 ( 0.305) 0.045 0.063 102 8.50 0.50 0.108 ( 0.304) 0.045 0.063 103 8.58 0.53 0.115 ( 0.302) 0.048 0.067 104 8.67 0.53 0.115 ( 0.301) 0.048 0.067 105 8.75 0.53 0.115 ( 0.300) 0.048 0.067 106 8.83 0.57 0.122 ( 0.298) 0.051 0.071 107 8.92 0.57 0.122 ( 0.297) 0.051 0.071 108 9.00 0.57 0.122 ( 0.295) 0.051 0.071 109 9.08 0.63 0.137 ( 0.294) 0.057 0.079 110 9.17 0.63 0.137 ( 0.293) 0.057 0.079 111 9.25 0.63 0.137 ( 0.291) 0.057 0.079 112 9.33 0.67 0.144 ( 0.290) 0.060 0.084 113 9.42 0.67 0.144 ( 0.288) 0.060 0.084 114 9.50 0.67 0.144 ( 0.287) 0.060 0.084 115 9.58 0.70 0.151 ( 0.286) 0.064 0.088 116 9.67 0.70 0.151 ( 0.284) 0.064 0.088 117 9.75 0.70 0.151 ( 0.283) 0.064 0.088 118 9.83 0.73 0.158 ( 0.282) 0.067 0.092 119 9.92 0.73 0.158 ( 0.280) 0.067 0.092 120 10.00 0.73 0.158 ( 0.279) 0.067 0.092 121 10.08 0.50 0.108 ( 0.277) 0.045 0.063 122 10.17 0.50 0.108 ( 0.276) 0.045 0.063 123 10.25 0.50 0.108 ( 0.275) 0.045 0.063 124 10.33 0.50 0.108 ( 0.273) 0.045 0.063 125 10.42 0.50 0.108 ( 0.272) 0.045 0.063 126 10.50 0.50 0.108 ( 0.271) 0.045 0.063 127 10.58 0.67 0.144 ( 0.269) 0.060 0.084 128 10.67 0.67 0.144 ( 0.268) 0.060 0.084 129 10.75 0.67 0.144 ( 0.267) 0.060 0.084 130 10.83 0.67 0.144 ( 0.266) 0.060 0.084 131 10.92 0.67 0.144 ( 0.264) 0.060 0.084 132 11.00 0.67 0.144 ( 0.263) 0.060 0.084 133 11.08 0.63 0.137 ( 0.262) 0.057 0.079 134 11.17 0.63 0.137 ( 0.260) 0.057 0.079 135 11.25 0.63 0.137 ( 0.259) 0.057 0.079 136 11.33 0.63 0.137 ( 0.258) 0.057 0.079 137 11.42 0.63 0.137 ( 0.256) 0.057 0.079 138 11.50 0.63 0.137 ( 0.255) 0.057 0.079 139 11.58 0.57 0.122 ( 0.254) 0.051 0.071 140 11.67 0.57 0.122 ( 0.253) 0.051 0.071 141 11.75 0.57 0.122 ( 0.251) 0.051 0.071 142 11.83 0.60 0.130 ( 0.250) 0.054 0.075 143 11.92 0.60 0.130 ( 0.249) 0.054 0.075 144 12.00 0.60 0.130 ( 0.248) 0.054 0.075 145 12.08 0.83 0.180 ( 0.246) 0.076 0.104 146 12.17 0.83 0.180 ( 0.245) 0.076 0.104 147 12.25 0.83 0.180 ( 0.244) 0.076 0.104 148 12.33 0.87 0.187 ( 0.243) 0.079 0.109 149 12.42 0.87 0.187 ( 0.242) 0.079 0.109 150 12.50 0.87 0.187 ( 0.240) 0.079 0.109 151 12.58 0.93 0.202 ( 0.239) 0.085 0.117 152 12.67 0.93 0.202 ( 0.238) 0.085 0.117 153 12.75 0.93 0.202 ( 0.237) 0.085 0.117 154 12.83 0.97 0.209 ( 0.236) 0.088 0.121 155 12.92 0.97 0.209 ( 0.234) 0.088 0.121 156 13.00 0.97 0.209 ( 0.233) 0.088 0.121 157 13.08 1.13 0.245 ( 0.232) 0.103 0.142 158 13.17 1.13 0.245 ( 0.231) 0.103 0.142 159 13.25 1.13 0.245 ( 0.230) 0.103 0.142 PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies PRO 2YR24HR Page 4 of 9
160 13.33 1.13 0.245 ( 0.228) 0.103 0.142 161 13.42 1.13 0.245 ( 0.227) 0.103 0.142 162 13.50 1.13 0.245 ( 0.226) 0.103 0.142 163 13.58 0.77 0.166 ( 0.225) 0.070 0.096 164 13.67 0.77 0.166 ( 0.224) 0.070 0.096 165 13.75 0.77 0.166 ( 0.223) 0.070 0.096 166 13.83 0.77 0.166 ( 0.222) 0.070 0.096 167 13.92 0.77 0.166 ( 0.220) 0.070 0.096 168 14.00 0.77 0.166 ( 0.219) 0.070 0.096 169 14.08 0.90 0.194 ( 0.218) 0.082 0.113 170 14.17 0.90 0.194 ( 0.217) 0.082 0.113 171 14.25 0.90 0.194 ( 0.216) 0.082 0.113 172 14.33 0.87 0.187 ( 0.215) 0.079 0.109 173 14.42 0.87 0.187 ( 0.214) 0.079 0.109 174 14.50 0.87 0.187 ( 0.213) 0.079 0.109 175 14.58 0.87 0.187 ( 0.212) 0.079 0.109 176 14.67 0.87 0.187 ( 0.210) 0.079 0.109 177 14.75 0.87 0.187 ( 0.209) 0.079 0.109 178 14.83 0.83 0.180 ( 0.208) 0.076 0.104 179 14.92 0.83 0.180 ( 0.207) 0.076 0.104 180 15.00 0.83 0.180 ( 0.206) 0.076 0.104 181 15.08 0.80 0.173 ( 0.205) 0.073 0.100 182 15.17 0.80 0.173 ( 0.204) 0.073 0.100 183 15.25 0.80 0.173 ( 0.203) 0.073 0.100 184 15.33 0.77 0.166 ( 0.202) 0.070 0.096 185 15.42 0.77 0.166 ( 0.201) 0.070 0.096 186 15.50 0.77 0.166 ( 0.200) 0.070 0.096 187 15.58 0.63 0.137 ( 0.199) 0.057 0.079 188 15.67 0.63 0.137 ( 0.198) 0.057 0.079 189 15.75 0.63 0.137 ( 0.197) 0.057 0.079 190 15.83 0.63 0.137 ( 0.196) 0.057 0.079 191 15.92 0.63 0.137 ( 0.195) 0.057 0.079 192 16.00 0.63 0.137 ( 0.194) 0.057 0.079 193 16.08 0.13 0.029 ( 0.193) 0.012 0.017 194 16.17 0.13 0.029 ( 0.192) 0.012 0.017 195 16.25 0.13 0.029 ( 0.191) 0.012 0.017 196 16.33 0.13 0.029 ( 0.190) 0.012 0.017 197 16.42 0.13 0.029 ( 0.189) 0.012 0.017 198 16.50 0.13 0.029 ( 0.188) 0.012 0.017 199 16.58 0.10 0.022 ( 0.187) 0.009 0.013 200 16.67 0.10 0.022 ( 0.186) 0.009 0.013 201 16.75 0.10 0.022 ( 0.185) 0.009 0.013 202 16.83 0.10 0.022 ( 0.184) 0.009 0.013 203 16.92 0.10 0.022 ( 0.183) 0.009 0.013 204 17.00 0.10 0.022 ( 0.182) 0.009 0.013 205 17.08 0.17 0.036 ( 0.181) 0.015 0.021 206 17.17 0.17 0.036 ( 0.181) 0.015 0.021 207 17.25 0.17 0.036 ( 0.180) 0.015 0.021 208 17.33 0.17 0.036 ( 0.179) 0.015 0.021 209 17.42 0.17 0.036 ( 0.178) 0.015 0.021 210 17.50 0.17 0.036 ( 0.177) 0.015 0.021 211 17.58 0.17 0.036 ( 0.176) 0.015 0.021 212 17.67 0.17 0.036 ( 0.175) 0.015 0.021 213 17.75 0.17 0.036 ( 0.174) 0.015 0.021 214 17.83 0.13 0.029 ( 0.173) 0.012 0.017 215 17.92 0.13 0.029 ( 0.173) 0.012 0.017 216 18.00 0.13 0.029 ( 0.172) 0.012 0.017 217 18.08 0.13 0.029 ( 0.171) 0.012 0.017 218 18.17 0.13 0.029 ( 0.170) 0.012 0.017 219 18.25 0.13 0.029 ( 0.169) 0.012 0.017 220 18.33 0.13 0.029 ( 0.168) 0.012 0.017 221 18.42 0.13 0.029 ( 0.168) 0.012 0.017 222 18.50 0.13 0.029 ( 0.167) 0.012 0.017 223 18.58 0.10 0.022 ( 0.166) 0.009 0.013 224 18.67 0.10 0.022 ( 0.165) 0.009 0.013 225 18.75 0.10 0.022 ( 0.164) 0.009 0.013 226 18.83 0.07 0.014 ( 0.164) 0.006 0.008 227 18.92 0.07 0.014 ( 0.163) 0.006 0.008 228 19.00 0.07 0.014 ( 0.162) 0.006 0.008 229 19.08 0.10 0.022 ( 0.161) 0.009 0.013 230 19.17 0.10 0.022 ( 0.160) 0.009 0.013 231 19.25 0.10 0.022 ( 0.160) 0.009 0.013 232 19.33 0.13 0.029 ( 0.159) 0.012 0.017 233 19.42 0.13 0.029 ( 0.158) 0.012 0.017 234 19.50 0.13 0.029 ( 0.158) 0.012 0.017 235 19.58 0.10 0.022 ( 0.157) 0.009 0.013 236 19.67 0.10 0.022 ( 0.156) 0.009 0.013 237 19.75 0.10 0.022 ( 0.155) 0.009 0.013 238 19.83 0.07 0.014 ( 0.155) 0.006 0.008 239 19.92 0.07 0.014 ( 0.154) 0.006 0.008 240 20.00 0.07 0.014 ( 0.153) 0.006 0.008 241 20.08 0.10 0.022 ( 0.153) 0.009 0.013 242 20.17 0.10 0.022 ( 0.152) 0.009 0.013 243 20.25 0.10 0.022 ( 0.151) 0.009 0.013 244 20.33 0.10 0.022 ( 0.151) 0.009 0.013 245 20.42 0.10 0.022 ( 0.150) 0.009 0.013 PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies PRO 2YR24HR Page 5 of 9
246 20.50 0.10 0.022 ( 0.149) 0.009 0.013 247 20.58 0.10 0.022 ( 0.149) 0.009 0.013 248 20.67 0.10 0.022 ( 0.148) 0.009 0.013 249 20.75 0.10 0.022 ( 0.148) 0.009 0.013 250 20.83 0.07 0.014 ( 0.147) 0.006 0.008 251 20.92 0.07 0.014 ( 0.146) 0.006 0.008 252 21.00 0.07 0.014 ( 0.146) 0.006 0.008 253 21.08 0.10 0.022 ( 0.145) 0.009 0.013 254 21.17 0.10 0.022 ( 0.145) 0.009 0.013 255 21.25 0.10 0.022 ( 0.144) 0.009 0.013 256 21.33 0.07 0.014 ( 0.143) 0.006 0.008 257 21.42 0.07 0.014 ( 0.143) 0.006 0.008 258 21.50 0.07 0.014 ( 0.142) 0.006 0.008 259 21.58 0.10 0.022 ( 0.142) 0.009 0.013 260 21.67 0.10 0.022 ( 0.141) 0.009 0.013 261 21.75 0.10 0.022 ( 0.141) 0.009 0.013 262 21.83 0.07 0.014 ( 0.140) 0.006 0.008 263 21.92 0.07 0.014 ( 0.140) 0.006 0.008 264 22.00 0.07 0.014 ( 0.139) 0.006 0.008 265 22.08 0.10 0.022 ( 0.139) 0.009 0.013 266 22.17 0.10 0.022 ( 0.138) 0.009 0.013 267 22.25 0.10 0.022 ( 0.138) 0.009 0.013 268 22.33 0.07 0.014 ( 0.138) 0.006 0.008 269 22.42 0.07 0.014 ( 0.137) 0.006 0.008 270 22.50 0.07 0.014 ( 0.137) 0.006 0.008 271 22.58 0.07 0.014 ( 0.136) 0.006 0.008 272 22.67 0.07 0.014 ( 0.136) 0.006 0.008 273 22.75 0.07 0.014 ( 0.136) 0.006 0.008 274 22.83 0.07 0.014 ( 0.135) 0.006 0.008 275 22.92 0.07 0.014 ( 0.135) 0.006 0.008 276 23.00 0.07 0.014 ( 0.135) 0.006 0.008 277 23.08 0.07 0.014 ( 0.134) 0.006 0.008 278 23.17 0.07 0.014 ( 0.134) 0.006 0.008 279 23.25 0.07 0.014 ( 0.134) 0.006 0.008 280 23.33 0.07 0.014 ( 0.133) 0.006 0.008 281 23.42 0.07 0.014 ( 0.133) 0.006 0.008 282 23.50 0.07 0.014 ( 0.133) 0.006 0.008 283 23.58 0.07 0.014 ( 0.133) 0.006 0.008 284 23.67 0.07 0.014 ( 0.133) 0.006 0.008 285 23.75 0.07 0.014 ( 0.132) 0.006 0.008 286 23.83 0.07 0.014 ( 0.132) 0.006 0.008 287 23.92 0.07 0.014 ( 0.132) 0.006 0.008 288 24.00 0.07 0.014 ( 0.132) 0.006 0.008 (Loss Rate Not Used)
Sum = 100.0 Sum = 12.5 Flood volume = Effective rainfall 1.04(In)
times area 7.0(Ac.)/[(In)/(Ft.)] = 0.6(Ac.Ft) Total soil loss = 0.76(In)
Total soil loss = 0.441(Ac.Ft)
Total rainfall = 1.80(In)
Flood volume = 26527.7 Cubic Feet
Total soil loss = 19209.7 Cubic Feet
-------------------------------------------------------------------- Peak flow rate of this hydrograph = 1.002(CFS)
-------------------------------------------------------------------- ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 24 - H O U R S T O R M
R u n o f f H y d r o g r a p h
-------------------------------------------------------------------- Hydrograph in 5 Minute intervals ((CFS))
-------------------------------------------------------------------- Time(h+m) Volume Ac.Ft Q(CFS) 0 2.5 5.0 7.5 10.0 ----------------------------------------------------------------------- 0+ 5 0.0002 0.03 Q | | | | 0+10 0.0006 0.05 Q | | | | 0+15 0.0010 0.06 Q | | | | 0+20 0.0015 0.08 Q | | | | 0+25 0.0021 0.09 Q | | | | 0+30 0.0027 0.09 Q | | | | 0+35 0.0033 0.09 Q | | | | 0+40 0.0040 0.09 Q | | | | 0+45 0.0046 0.09 Q | | | | 0+50 0.0053 0.10 Q | | | | 0+55 0.0061 0.12 Q | | | | 1+ 0 0.0069 0.12 Q | | | | 1+ 5 0.0076 0.10 Q | | | | 1+10 0.0082 0.09 Q | | | | 1+15 0.0088 0.09 Q | | | | 1+20 0.0094 0.09 Q | | | | 1+25 0.0100 0.09 Q | | | | 1+30 0.0106 0.09 Q | | | | 1+35 0.0113 0.09 Q | | | | 1+40 0.0119 0.09 Q | | | | 1+45 0.0125 0.09 Q | | | | 1+50 0.0132 0.10 Q | | | | PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies PRO 2YR24HR Page 6 of 9
1+55 0.0140 0.12 Q | | | | 2+ 0 0.0148 0.12 Q | | | | 2+ 5 0.0156 0.12 QV | | | | 2+10 0.0164 0.12 QV | | | | 2+15 0.0172 0.12 QV | | | | 2+20 0.0181 0.12 QV | | | | 2+25 0.0189 0.12 QV | | | | 2+30 0.0197 0.12 QV | | | | 2+35 0.0206 0.13 QV | | | | 2+40 0.0216 0.15 QV | | | | 2+45 0.0226 0.15 QV | | | | 2+50 0.0236 0.15 QV | | | | 2+55 0.0247 0.15 QV | | | | 3+ 0 0.0257 0.15 QV | | | | 3+ 5 0.0267 0.15 QV | | | | 3+10 0.0277 0.15 QV | | | | 3+15 0.0287 0.15 QV | | | | 3+20 0.0297 0.15 QV | | | | 3+25 0.0307 0.15 Q V | | | | 3+30 0.0318 0.15 Q V | | | | 3+35 0.0328 0.15 Q V | | | | 3+40 0.0338 0.15 Q V | | | | 3+45 0.0348 0.15 Q V | | | | 3+50 0.0359 0.16 Q V | | | | 3+55 0.0371 0.17 Q V | | | | 4+ 0 0.0384 0.18 Q V | | | | 4+ 5 0.0396 0.18 Q V | | | | 4+10 0.0408 0.18 Q V | | | | 4+15 0.0420 0.18 Q V | | | | 4+20 0.0433 0.19 Q V | | | | 4+25 0.0447 0.20 Q V | | | | 4+30 0.0462 0.21 Q V | | | | 4+35 0.0476 0.21 Q V | | | | 4+40 0.0490 0.21 Q V | | | | 4+45 0.0504 0.21 Q V | | | | 4+50 0.0520 0.22 Q V | | | | 4+55 0.0536 0.23 Q V | | | | 5+ 0 0.0552 0.24 Q V | | | | 5+ 5 0.0566 0.20 Q V | | | | 5+10 0.0578 0.18 Q V | | | | 5+15 0.0591 0.18 Q V | | | | 5+20 0.0604 0.19 Q V | | | | 5+25 0.0618 0.20 Q V | | | | 5+30 0.0632 0.21 Q V | | | | 5+35 0.0647 0.22 Q V | | | | 5+40 0.0664 0.23 Q V | | | | 5+45 0.0680 0.24 Q V | | | | 5+50 0.0696 0.24 Q V | | | | 5+55 0.0712 0.24 Q V | | | | 6+ 0 0.0729 0.24 Q V | | | | 6+ 5 0.0746 0.25 |Q V | | | | 6+10 0.0764 0.26 |Q V | | | | 6+15 0.0782 0.27 |Q V | | | | 6+20 0.0801 0.27 |Q V | | | | 6+25 0.0819 0.27 |Q V | | | | 6+30 0.0837 0.27 |Q V | | | | 6+35 0.0857 0.28 |Q V | | | | 6+40 0.0877 0.29 |Q V | | | | 6+45 0.0897 0.29 |Q V | | | | 6+50 0.0917 0.29 |Q V | | | | 6+55 0.0938 0.29 |Q V | | | | 7+ 0 0.0958 0.29 |Q V | | | | 7+ 5 0.0978 0.29 |Q V | | | | 7+10 0.0998 0.29 |Q V | | | | 7+15 0.1019 0.29 |Q V | | | | 7+20 0.1040 0.31 |Q V | | | | 7+25 0.1062 0.32 |Q V | | | | 7+30 0.1085 0.32 |Q V | | | | 7+35 0.1108 0.34 |Q V | | | | 7+40 0.1132 0.35 |Q V | | | | 7+45 0.1157 0.35 |Q V | | | | 7+50 0.1182 0.37 |Q V | | | | 7+55 0.1209 0.38 |Q V | | | | 8+ 0 0.1235 0.38 |Q V | | | | 8+ 5 0.1264 0.42 |Q V | | | | 8+10 0.1294 0.44 |Q V | | | | 8+15 0.1324 0.44 |Q V | | | | 8+20 0.1355 0.44 |Q V | | | | 8+25 0.1385 0.44 |Q V| | | | 8+30 0.1416 0.44 |Q V| | | | 8+35 0.1447 0.46 |Q V| | | | 8+40 0.1479 0.47 |Q V| | | | 8+45 0.1512 0.47 |Q V| | | | 8+50 0.1546 0.49 |Q V | | | 8+55 0.1580 0.50 |Q V | | | 9+ 0 0.1614 0.50 | Q V | | | PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies PRO 2YR24HR Page 7 of 9
9+ 5 0.1651 0.53 | Q V | | | 9+10 0.1689 0.56 | Q |V | | | 9+15 0.1728 0.56 | Q |V | | | 9+20 0.1768 0.58 | Q |V | | | 9+25 0.1808 0.59 | Q |V | | | 9+30 0.1849 0.59 | Q | V | | | 9+35 0.1891 0.61 | Q | V | | | 9+40 0.1933 0.62 | Q | V | | | 9+45 0.1976 0.62 | Q | V | | | 9+50 0.2019 0.64 | Q | V | | | 9+55 0.2064 0.65 | Q | V | | | 10+ 0 0.2109 0.65 | Q | V | | | 10+ 5 0.2145 0.53 | Q | V | | | 10+10 0.2177 0.46 |Q | V | | | 10+15 0.2207 0.44 |Q | V | | | 10+20 0.2238 0.44 |Q | V | | | 10+25 0.2268 0.44 |Q | V | | | 10+30 0.2299 0.44 |Q | V | | | 10+35 0.2335 0.52 | Q | V | | | 10+40 0.2375 0.58 | Q | V | | | 10+45 0.2415 0.59 | Q | V | | | 10+50 0.2456 0.59 | Q | V | | | 10+55 0.2496 0.59 | Q | V | | | 11+ 0 0.2537 0.59 | Q | V | | | 11+ 5 0.2576 0.57 | Q | V | | | 11+10 0.2615 0.56 | Q | V | | | 11+15 0.2654 0.56 | Q | V | | | 11+20 0.2692 0.56 | Q | V | | | 11+25 0.2731 0.56 | Q | V | | | 11+30 0.2769 0.56 | Q | V | | | 11+35 0.2806 0.53 | Q | V | | | 11+40 0.2841 0.51 | Q | V | | | 11+45 0.2875 0.50 | Q | V | | | 11+50 0.2911 0.52 | Q | V| | | 11+55 0.2947 0.53 | Q | V| | | 12+ 0 0.2984 0.53 | Q | V| | | 12+ 5 0.3028 0.65 | Q | V| | | 12+10 0.3078 0.72 | Q | V | | 12+15 0.3129 0.74 | Q | V | | 12+20 0.3180 0.75 | Q | V | | 12+25 0.3233 0.76 | Q | |V | | 12+30 0.3286 0.77 | Q | |V | | 12+35 0.3341 0.80 | Q | |V | | 12+40 0.3397 0.82 | Q | | V | | 12+45 0.3454 0.83 | Q | | V | | 12+50 0.3512 0.84 | Q | | V | | 12+55 0.3571 0.85 | Q | | V | | 13+ 0 0.3630 0.85 | Q | | V | | 13+ 5 0.3694 0.94 | Q | | V | | 13+10 0.3763 0.99 | Q | | V | | 13+15 0.3832 1.00 | Q | | V | | 13+20 0.3901 1.00 | Q | | V | | 13+25 0.3970 1.00 | Q | | V | | 13+30 0.4039 1.00 | Q | | V | | 13+35 0.4095 0.82 | Q | | V | | 13+40 0.4144 0.70 | Q | | V | | 13+45 0.4190 0.68 | Q | | V | | 13+50 0.4237 0.68 | Q | | V | | 13+55 0.4284 0.68 | Q | | V | | 14+ 0 0.4330 0.68 | Q | | V | | 14+ 5 0.4382 0.74 | Q | | V | | 14+10 0.4436 0.79 | Q | | V| | 14+15 0.4491 0.80 | Q | | V| | 14+20 0.4544 0.78 | Q | | V| | 14+25 0.4597 0.77 | Q | | V | 14+30 0.4650 0.77 | Q | | V | 14+35 0.4703 0.77 | Q | | V | 14+40 0.4756 0.77 | Q | | |V | 14+45 0.4808 0.77 | Q | | |V | 14+50 0.4860 0.75 | Q | | |V | 14+55 0.4911 0.74 | Q | | | V | 15+ 0 0.4962 0.74 | Q | | | V | 15+ 5 0.5011 0.72 | Q | | | V | 15+10 0.5060 0.71 | Q | | | V | 15+15 0.5109 0.71 | Q | | | V | 15+20 0.5156 0.69 | Q | | | V | 15+25 0.5203 0.68 | Q | | | V | 15+30 0.5250 0.68 | Q | | | V | 15+35 0.5292 0.61 | Q | | | V | 15+40 0.5331 0.57 | Q | | | V | 15+45 0.5370 0.56 | Q | | | V | 15+50 0.5408 0.56 | Q | | | V | 15+55 0.5447 0.56 | Q | | | V | 16+ 0 0.5486 0.56 | Q | | | V | 16+ 5 0.5507 0.31 |Q | | | V | 16+10 0.5517 0.15 Q | | | V | PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies PRO 2YR24HR Page 8 of 9
16+15 0.5525 0.12 Q | | | V | 16+20 0.5534 0.12 Q | | | V | 16+25 0.5542 0.12 Q | | | V | 16+30 0.5550 0.12 Q | | | V | 16+35 0.5557 0.10 Q | | | V | 16+40 0.5563 0.09 Q | | | V | 16+45 0.5569 0.09 Q | | | V | 16+50 0.5575 0.09 Q | | | V | 16+55 0.5581 0.09 Q | | | V | 17+ 0 0.5587 0.09 Q | | | V | 17+ 5 0.5596 0.12 Q | | | V | 17+10 0.5606 0.14 Q | | | V | 17+15 0.5616 0.15 Q | | | V | 17+20 0.5626 0.15 Q | | | V | 17+25 0.5636 0.15 Q | | | V | 17+30 0.5646 0.15 Q | | | V | 17+35 0.5656 0.15 Q | | | V | 17+40 0.5667 0.15 Q | | | V | 17+45 0.5677 0.15 Q | | | V | 17+50 0.5686 0.13 Q | | | V | 17+55 0.5694 0.12 Q | | | V | 18+ 0 0.5702 0.12 Q | | | V | 18+ 5 0.5710 0.12 Q | | | V | 18+10 0.5718 0.12 Q | | | V | 18+15 0.5726 0.12 Q | | | V | 18+20 0.5735 0.12 Q | | | V | 18+25 0.5743 0.12 Q | | | V | 18+30 0.5751 0.12 Q | | | V | 18+35 0.5758 0.10 Q | | | V | 18+40 0.5764 0.09 Q | | | V | 18+45 0.5770 0.09 Q | | | V | 18+50 0.5775 0.07 Q | | | V | 18+55 0.5779 0.06 Q | | | V | 19+ 0 0.5783 0.06 Q | | | V | 19+ 5 0.5789 0.08 Q | | | V | 19+10 0.5794 0.09 Q | | | V | 19+15 0.5801 0.09 Q | | | V | 19+20 0.5808 0.10 Q | | | V | 19+25 0.5816 0.12 Q | | | V | 19+30 0.5824 0.12 Q | | | V | 19+35 0.5831 0.10 Q | | | V | 19+40 0.5837 0.09 Q | | | V | 19+45 0.5843 0.09 Q | | | V | 19+50 0.5848 0.07 Q | | | V | 19+55 0.5852 0.06 Q | | | V | 20+ 0 0.5856 0.06 Q | | | V | 20+ 5 0.5862 0.08 Q | | | V | 20+10 0.5868 0.09 Q | | | V | 20+15 0.5874 0.09 Q | | | V | 20+20 0.5880 0.09 Q | | | V | 20+25 0.5886 0.09 Q | | | V | 20+30 0.5892 0.09 Q | | | V | 20+35 0.5898 0.09 Q | | | V | 20+40 0.5904 0.09 Q | | | V | 20+45 0.5910 0.09 Q | | | V | 20+50 0.5915 0.07 Q | | | V | 20+55 0.5919 0.06 Q | | | V | 21+ 0 0.5923 0.06 Q | | | V | 21+ 5 0.5929 0.08 Q | | | V | 21+10 0.5935 0.09 Q | | | V | 21+15 0.5941 0.09 Q | | | V| 21+20 0.5946 0.07 Q | | | V| 21+25 0.5950 0.06 Q | | | V| 21+30 0.5954 0.06 Q | | | V| 21+35 0.5959 0.08 Q | | | V| 21+40 0.5965 0.09 Q | | | V| 21+45 0.5971 0.09 Q | | | V| 21+50 0.5976 0.07 Q | | | V| 21+55 0.5980 0.06 Q | | | V| 22+ 0 0.5984 0.06 Q | | | V| 22+ 5 0.5989 0.08 Q | | | V| 22+10 0.5995 0.09 Q | | | V| 22+15 0.6002 0.09 Q | | | V| 22+20 0.6007 0.07 Q | | | V| 22+25 0.6011 0.06 Q | | | V| 22+30 0.6015 0.06 Q | | | V| 22+35 0.6019 0.06 Q | | | V| 22+40 0.6023 0.06 Q | | | V| 22+45 0.6027 0.06 Q | | | V| 22+50 0.6031 0.06 Q | | | V| 22+55 0.6035 0.06 Q | | | V| 23+ 0 0.6039 0.06 Q | | | V| 23+ 5 0.6043 0.06 Q | | | V| 23+10 0.6047 0.06 Q | | | V| 23+15 0.6051 0.06 Q | | | V| 23+20 0.6055 0.06 Q | | | V| PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies PRO 2YR24HR Page 9 of 9
23+25 0.6059 0.06 Q | | | V| 23+30 0.6063 0.06 Q | | | V| 23+35 0.6068 0.06 Q | | | V| 23+40 0.6072 0.06 Q | | | V| 23+45 0.6076 0.06 Q | | | V| 23+50 0.6080 0.06 Q | | | V| 23+55 0.6084 0.06 Q | | | V| 24+ 0 0.6088 0.06 Q | | | V| 24+ 5 0.6090 0.03 Q | | | V| 24+10 0.6090 0.00 Q | | | V| ----------------------------------------------------------------------- PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies - 34 -

Appendix 8: Source Control
Pollutant Sources/Source Control Checklist

PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies

STORMWATER POLLUTANT SOURCES/SOURCE CONTROL CHECKLIST

How to use this worksheet (also see instructions in Section G of the WQMP Template):

1. Review Column 1 and identify which of these potential sources of stormwater pollutants apply to your site. Check each box that applies.

2. Review Column 2 and incorporate all of the corresponding applicable BMPs in your WQMP Exhibit.

3. Review Columns 3 and 4 and incorporate all of the corresponding applicable permanent controls and operational BMPs in your WQMP. Use the format shown in Table G.1on page 23 of this WQMP Template. Describe your specific BMPs in an accompanying narrative, and explain any special conditions or situations that required omitting BMPs or substituting alternative BMPs for those shown here.




Maintain and periodically repaint or
replace inlet markings.

Provide stormwater pollution
prevention information to new site
owners, lessees, or operators.

See applicable operational 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.”
 B. Interior floor drains
and elevator shaft sump
pumps
 State that interior floor drains and
elevator shaft sump pumps will be
plumbed to sanitary sewer.
 Inspect and maintain drains to prevent
blockages and overflow.
 C. Interior parking
garages
 State that parking garage floor
drains will be plumbed to the
sanitary sewer.
 Inspect and maintain drains to prevent
blockages and overflow.

PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies

STORMWATER POLLUTANT SOURCES/SOURCE CONTROL CHECKLIST




Show locations of native trees or
areas of shrubs and ground cover to
be undisturbed and retained.

Show self-retaining landscape
areas, if any.

Show stormwater treatment and
hydrograph modification
management BMPs. (See
instructions in Chapter 3, Step 5
and guidance in Chapter 5.)



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 of 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,
ecological consistency, and plant
interactions.





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/
Error!
Hyperlink reference not valid.

Provide IPM information to new
owners, lessees and operators.

PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies

STORMWATER POLLUTANT SOURCES/SOURCE CONTROL CHECKLIST


For restaurants, grocery stores, and
other food service operations, show
location (indoors or in a covered
area outdoors) of a floor sink or
other area for cleaning floor mats,
containers, and equipment.

On the drawing, show a note that
this drain will be connected to a
grease interceptor before
discharging to the sanitary sewer.



Describe the location and features
of the designated cleaning area.

Describe the items to be cleaned in
this facility and how it has been
sized to insure that the largest
items can be accommodated.

 See the brochure, “The Food Service
Industry Best Management Practices for:

Restaurants, Grocery Stores,
Delicatessens and Bakeries” at
http://rcflood.org/stormwater/
Provide this brochure to new site
owners, lessees, and operators.
 G. Refuse areas 




Show where site refuse and
recycled materials will be handled
and stored for pickup. See local
municipal requirements for sizes
and other details of refuse areas.

If dumpsters or other receptacles
are outdoors, show how the
designated area will be covered,
graded, and paved to prevent run-
on and show locations of berms to
prevent runoff from the area.

Any drains from dumpsters,
compactors, and tallow bin areas
shall be connected to a grease
removal device before discharge to
sanitary sewer.



State how site refuse will be
handled and provide supporting
detail to what is shown on plans.

State that signs will be posted on or
near dumpsters with the words “Do
not dump hazardous materials
here” or similar.
 State how the following will be
implemented:

Provide adequate number of
receptacles. Inspect receptacles
regularly; repair or replace leaky
receptacles. Keep receptacles covered.

Prohibit/prevent dumping of liquid or
hazardous wastes. Post “no hazardous
materials” signs. Inspect and pick up
litter daily and clean up spills
immediately. Keep spill control
materials available on-site. See Fact
Sheet SC-34, “Waste Handling and
Disposal” in the CASQA Stormwater
Quality Handbooks at
www.cabmphandbooks.com
PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies

STORMWATER POLLUTANT SOURCES/SOURCE CONTROL CHECKLIST

No processes to drain to exterior or
to storm drain system.”
 See Fact Sheet SC-10, “Non-
Stormwater Discharges” in the
CASQA Stormwater Quality
Handbooks at
www.cabmphandbooks.com
See the brochure “Industrial &
Commercial Facilities Best Management
Practices for: Industrial, Commercial
Facilities” at
http://rcflood.org/stormwater/
PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies

STORMWATER POLLUTANT SOURCES/SOURCE CONTROL CHECKLIST



Show any outdoor storage areas,
including how materials will be
covered. Show how areas will be
graded and bermed to prevent run-
on or run-off from area.

Storage of non-hazardous liquids
shall be covered by a roof and/or
drain to the sanitary sewer system,
and be contained by berms, dikes,
liners, or vaults.

Storage of hazardous materials and
wastes must be in compliance with
the local hazardous materials
ordinance and a Hazardous
Materials Management Plan for the
site.

Include a detailed description of
materials to be stored, storage
areas, and structural features to
prevent pollutants from entering
storm drains.

Where appropriate, reference
documentation of compliance with
the requirements of Hazardous
Materials Programs for:
 Hazardous Waste Generation
 Hazardous Materials Release
Response and Inventory
 California Accidental Release
(CalARP)
 Aboveground Storage Tank
 Uniform Fire Code Article 80
Section 103(b) & (c) 1991
 Underground Storage Tank
www.cchealth.org/groups/hazmat
/

 See the Fact Sheets SC-31, “Outdoor
Liquid Container Storage” and SC-33,
“Outdoor Storage of Raw Materials ”
in the CASQA Stormwater Quality
Handbooks at
www.cabmphandbooks.com
PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies

STORMWATER POLLUTANT SOURCES/SOURCE CONTROL CHECKLIST

IF THESE SOURCES WILL BE
ON THE PROJECT SITE … … THEN YOUR WQMP SHOULD INCLUDE THESE SOURCE CONTROL BMPs, AS APPLICABLE 1 Potential Sources of
Runoff Pollutants
2 Permanent Controls—Show on
WQMP Drawings
3 Permanent Controls—List in WQMP
Table and Narrative
4 Operational BMPs—Include in WQMP
Table and Narrative
 J. Vehicle and
Equipment Cleaning
 Show on drawings as appropriate:
(1) Commercial/industrial facilities
having vehicle/equipment cleaning
needs shall either provide a
covered, bermed area for washing
activities or discourage
vehicle/equipment washing by
removing hose bibs and installing
signs prohibiting such uses.
(2) Multi-dwelling complexes shall
have a paved, bermed, and covered
car wash area (unless car washing
is prohibited on-site and hoses are
provided with an automatic shut-
off to discourage such use).
(3) Washing areas for cars, vehicles,
and equipment shall be paved,
designed to prevent run-on to or
runoff from the area, and plumbed
to drain to the sanitary sewer.
(4) Commercial car wash facilities
shall be designed such that no
runoff from the facility is
discharged to the storm drain
system. Wastewater from the
facility shall discharge to the
sanitary sewer, or a wastewater
reclamation system shall be
installed.
 If a car wash area is not provided,
describe any measures taken to
discourage on-site car washing and
explain how these will be enforced.



Describe operational measures to
implement the following (if
applicable):

Washwater from vehicle and
equipment washing operations shall
not be discharged to the storm drain
system. Refer to “Outdoor Cleaning
Activities and Professional Mobile Service
Providers” for many of the Potential
Sources of Runoff Pollutants categories
below. Brochure can be found at
http://rcflood.org/stormwater/
Car dealerships and similar may
rinse cars with water only.

PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies

STORMWATER POLLUTANT SOURCES/SOURCE CONTROL CHECKLIST



Accommodate all vehicle
equipment repair and maintenance
indoors. Or designate an outdoor
work area and design the area to
prevent run-on and runoff of
stormwater.

Show secondary containment for
exterior work areas where motor
oil, brake fluid, gasoline, diesel
fuel, radiator fluid, acid-containing
batteries or other hazardous
materials or hazardous wastes are
used or stored. Drains shall not be
installed within the secondary
containment areas.

Add a note on the plans that states
either (1) there are no floor drains,
or (2) floor drains are connected to
wastewater pretreatment systems
prior to discharge to the sanitary
sewer and an industrial waste
discharge permit will be obtained.





State that no vehicle repair or
maintenance will be done outdoors,
or else describe the required
features of the outdoor work area.

State that there are no floor drains
or if there are floor drains, note the
agency from which an industrial
waste discharge permit will be
obtained and that the design meets
that agency’s requirements.

State that there are no tanks,
containers or sinks to be used for
parts cleaning or rinsing or, if there
are, note the agency from which an
industrial waste discharge permit
will be obtained and that the
design meets that agency’s
requirements.




In the Stormwater Control Plan, note
that all of the following restrictions
apply to use the site:

No person shall dispose of, nor permit
the disposal, directly or indir
ectly of
vehicle fluids, hazardous materials, or
rinsewater from parts cleaning into
storm drains.

No vehicle fluid removal shall be
performed outside a building, nor on
asphalt or ground surfaces, whether
inside or outside a building, except in
such a manner as to ensure that any
spilled fluid will be in an area of
secondary containment. Leaking
vehicle fluids shall be contained or
drained from the vehicle immediately.

No person shall leave unattended drip
parts or other open containers
containing vehicle fluid, unless such
containers are in use or in an area of
secondary containment.

Refer to “Automotive Maintenance & Car
Care Best Management Practices for Auto
Body Shops, Auto Repair Shops, Car
Dealerships, Gas Stations and Fleet
Service Operations”. Brochure can be
found at http://rcflood.org/stormwater/
Refer to Outdoor Cleaning Activities and
Professional Mobile Service Providers for
many of the Potential Sources of
Runoff Pollutants categories below.

Brochure can be found at
http://rcflood.org/stormwater/
PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies

STORMWATER POLLUTANT SOURCES/SOURCE CONTROL CHECKLIST


Fueling areas6 shall have
impermeable floors (i.e., portland
cement concrete or equivalent
smooth impervious surface) that
are: a) graded at the minimum
slope necessary to prevent ponding;
and b) separated from the rest of
the site by a grade break that
prevents run-on of stormwater to
the maximum extent practicable.

Fueling areas shall be covered by a
canopy that extends a minimum of
ten feet in each direction from each
pump. [Alternative: The fueling
area must be covered and the
cover’s minimum dimensions must
be equal to or greater than the area
within the grade break or fuel
dispensing area

1.] The canopy [or
cover] shall not drain onto the
fueling area.



The property owner shall dry sweep
the fueling area routinely.

See the Fact Sheet SD-30 , “Fueling
Areas” in the CASQA Stormwater
Quality Handbooks at
www.cabmphandbooks.com

6 The fueling area shall be defined as the area extending a minimum of 6.5 feet from the corner of each fuel dispenser or the length at which the hose and nozzle assembly may be operated plus a minimum of one foot, whichever is greater.

PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies

STORMWATER POLLUTANT SOURCES/SOURCE CONTROL CHECKLIST




Show a preliminary design for the
loading dock area, including
roofing and drainage. Loading
docks shall be covered and/or
graded to minimize run-on to and
runoff from the loading area. Roof
downspouts shall be positioned to
direct stormwater away from the
loading area. Water from loading
dock areas shall be drained to the
sanitary sewer, or diverted and
collected for ultimate discharge to
the sanitary sewer.

Loading dock areas draining
directly to the sanitary sewer shall
be equipped with a spill control
valve or equivalent device, which
shall be kept closed during periods
of operation.

Provide a roof overhang over the
loading area or install door skirts
(cowling) at each bay that enclose
the end of the trailer.



Move loaded and unloaded items
indoors as soon as possible.

See Fact Sheet SC-30, “Outdoor
Loading and Unloading,” in the
CASQA Stormwater Quality
Handbooks at
www.cabmphandbooks.com
PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies

STORMWATER POLLUTANT SOURCES/SOURCE CONTROL CHECKLIST








O. Miscellaneous Drain
or Wash Water or Other
Sources
Boiler drain lines
Condensate drain lines
Rooftop equipment
Drainage sumps
Roofing, gutters, and
trim.

Other sources





Boiler drain lines shall be directly
or indirectly connected to the
sanitary sewer system and may not
discharge to the storm drain
system.

Condensate drain lines may
discharge to landscaped areas if the
flow is small enough that runoff
will not occur. Condensate drain
lines may not discharge to the
storm drain system.

Rooftop equipment with potential
to produce pollutants shall be
roofed and/or have secondary
containment.

Any drainage sumps on-site shall
feature a sediment sump to reduce
the quantity of sediment in
pumped water.

Avoid roofing, gutters, and trim
made of copper or other
unprotected metals that may leach
into runoff.

Include controls for other sources
as specified by local reviewer.

PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies

STORMWATER POLLUTANT SOURCES/SOURCE CONTROL CHECKLIST

PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies - 35 -

Appendix 9: O&M
Operation and Maintenance Plan and Documentation of Finance, Maintenance and Recording Mechanisms

PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies Water Quality Management Plan (WQMP)
River Pointe
Riverside

Property Owner
Beazer Homes, 310 Commerce Street Irvine, CA 92602 – (949) 333-9592 Operations & Maintenance Responsibility for Treatment Control BMP’s

BMP Required
Maintenance
Frequency Maintenance Requirements Responsibility
Trash Weekly Empty Dumpsters Property Owner
Roof Drains/
Gutters
Before wet
season, or
significant rain
event, or when
needed
Roof Gutters shall be visually inspected for defects and possible leakage. Damage or defects found shall be
corrected as soon as possible.

Owners should avoid use of gutters, roofing, and trim made of copper so as to prevent the metal from leaching into runoff.

Property Owner

INFILTRATION
BASIN

Bi-Weekly

Semi-Annual

Annually

As Needed
Mow, weed, trim and remove accumulation of trash debris and/or sediment. Routine inspections for areas of standing water within the BMP and corrective measures to restore proper infiltration rates are necessary.

Trim Vegetation at the beginning and end of the wet season to prevent establishment of woody vegetation. Replant
eroded or barren spots to prevent erosion and accumulation of sediment.

Per Condition of Approval 90.FLOODRI all BMPs are to
be inspected, and if required, cleaned no later than October 15 each year

Stabilize eroded banks, repair undercut and eroded areas at inflow and outflow areas, maintain access to the basin for regular maintenance, mow as appropriate for vegetative
cover species, monitor health of vegetation and replace as necessary, control mosquitos as necessary, remove liter and debris. Mulch replacement may be necessary on an
occasional basis to fill in voids, mulching should be done prior to the wet season. Unclog underdrain, and regulate soil pH.

For additional maintenance information please see
Appendix 10 of the WQMP
Grading Plans and BMP Map provided in WQMP
document provide additional information on location of
Bio-retention facility and tributary areas.

Home Owners
Association

Self-Retaining/
Landscape Areas
Bi-Weekly Mow, weed, trim and remove accumulation of trash deb ris
and/or sediment. Retaining areas should be mowed at 4-6 inches in height if grass is proposed.

Maintain landscaping using minimal pesticides

Home Owners
Association
BMP's should start and be inspected prior to forecast rain, daily during extended rain events, after rain events, weekly during the rainy season, and at two-week intervals during the non-rainy season.

PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies Water Quality Management Plan (WQMP)
River Pointe
Riverside

Property Owner
Beazer Homes, 310 Commerce Street Irvine, CA 92602 – (949) 333-9592 Funding
Funding for Ongoing Maintenance will be provided by the Home Owner’s Association.

PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies Water Quality Management Plan (WQMP)
River Pointe
Riverside

Property Owner
Beazer Homes, 310 Commerce Street Irvine, CA 92602 – (949) 333-9592 Basin Site Maintenance Summary Form
Date: Inspector Name: Basin:

Maintenance Performed:

Date: Inspector Name: Basin:

Maintenance Performed:

Date: Inspector Name: Basin:

Maintenance Performed:

Date: Inspector Name: Basin:

Maintenance Performed:

Date: Inspector Name: Basin:

Maintenance Performed:

Date: Inspector Name: Basin:

Maintenance Performed:

Date: Inspector Name: Basin:

Maintenance Performed:

Date: Inspector Name: Basin:

Maintenance Performed:

Date: Inspector Name: Basin:

Maintenance Performed:

Date: Inspector Name: Basin:

Maintenance Performed:

Date: Inspector Name: Basin:

Maintenance Performed:

Date: Inspector Name: Basin:

Maintenance Performed:

Date: Inspector Name: Basin:

Maintenance Performed:

Date: Inspector Name: Basin:

Maintenance Performed:

PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies WHEN RECORDED MAIL TO:

City Clerk
City of Riverside
City Hall, 3900 Main Street
Riverside, CA 92522

Planning Case: P__-____

For Recorder’s Office Use Only

COVENANT AND AGREEMENT

ESTABLISHING NOTIFICATION PROCESS AND RESPONSIBILITY FOR

WATER QUALITY MANAGEMENT PLAN IMPLEMENTATION AND MAINTENANCE

THIS COVENANT AND AGREEMENT FOR WATER QUALITY
MANAGE
MENT PLAN IMPLEMENTATION AND MAINTENANCE is made and entered into this ______ day of __________________, 20__, by _____ {Insert Name of Owner} ______ _____________________________(“Declarant”), with reference to the following facts:

A. Declarant is the fee owner of the re al property (the "Pr operty") situated in
the City of Riverside, County of Riverside, State of California, and legally described in Exhibit “A”, which is attached hereto and incorporated within by reference.

B. Declarant has applied to the C ity of Riverside (“City”) for ____________ _________{Insert Project Description for Above Referenced Planning Case} ________________
________________________________________________________________________.

C. As a condition of approval and p
rior to the map recordation and/or
issuance of any permits, the City is requiring Declarant to ex ecute and record an agreement stating that the future property owners shall be informed of the requirements to implement and maintain the Best Management Practices (“BMPs”) as described in the approved project specific Water Quality Management Plan.

D. Declarant intends by this docum
ent to comply with the conditions imposed
by the City and to impose upon the Property mutu ally beneficial restrictions, conditions, covenants and agreements for the benefit of Property.

NOW, THEREFORE, for the purposes of com
plying with the conditions imposed
by the City of Riverside for the approval of Planning Case P__-____, Declarant hereby declares that the Property is and hereafter shall be held, conveyed, transferred, mortgaged, encumbered, leased, rented, used, occupied, sold and im proved subject to the following declarations, limitations, covenants, conditions, restrictions and easements, all of which are imposed as PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies

equitable servitudes pursuant to a general plan for the developm ent of the Property for the purpose of enhancing and protecting the value and attractiveness of the Property, and each Parcel thereof, in accordance with the plan for the improvement of the Property, and to comply with certain conditions imposed by th e City for the approval of P __-____, and shall be binding and inure to the benefit of each successor and assignee in interest of each such party. Any conveyance, transfer, sale, assignment, lease or sublease made by Declarant of a Parcel of the Property shall be and hereby is d eemed to incorporate by reference all the provisions of the Covenant and Agreement including, but not limited to, all the covenants, conditions, restrictions, limitations, grants of easement, rights, rights-of-way, and equitable servitude contained herein.

1. This Covenant and Agreement he re
by establishes a notification process
for future individual property owners to ensure they are subject to and adhere to the Water Quality Management Plan implementation measures and that it shall be the responsibility of the Declarant, its heirs, successors and assigns to implement and maintain all Best Management Practices (BMPs) in good working order.

2. Declarant shall use its best efforts to dilig
ently implement and maintain all
BMPs in a manner assuring peak performance at all times. All reasonable precautions shall be exercised by Declarant, its heirs, successors a nd assigns, in the removal and extraction of any material(s) from the BMPs and the ultimate disposal of the material(s) in a manner consistent with all relevant laws and regulations in effect at the time. As may be requested from time to time by the City, Declarant, its heirs, success ors and assigns shall pr ovide the City with documentation identifying the material(s) removed, the quantity, and disposal destination.

3. In the event Declarant, or its heirs, successors or assign s, fails to undertake
the maintenance contemplated by this Covenant and Agreement within twenty-one (21) days of being given written notice by the City, or fails to complete any maintenance contemplated by this Covenant and Agreement with reasonable diligen ce, the City is hereby authorized to cause any maintenance necessary to be completed and charge the entire cost and expense to the Declarant or Declarant’s successors or assigns, including administrative costs, reasonable attorneys fees and interest thereon at the maximum rate author ized by the Civil Code from the date of the notice of expense until paid in full. As an additional remedy, the Public Works Director may withdraw any previous urban runoff-related approval with re spect to the Property on which BMPs have been installed and/or implemented un til such time as Declarant, its heirs, successors or assigns, repays to City its reasonable costs incurred in accordance with this paragraph.

4. Any person who now or hereafter owns or acquires any right, title or inte
rest in or to any parcel of the Property shall be deemed to have consented and agreed to every covenant, condition, restriction and easement contained herein.

5. In addition, each of the provision s hereof shall operate as covenants running with the land for the benefit of the Property and each Parcel thereof and shall inure to the
benefit of all owners of the Parcels thereof, th eir successors and assigns in interest, and shall apply to and bind each successive owner of each Parcel, their successors and assigns in interest.

PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies

6. The terms of this Covenant and Agreem ent may be enforced by the City, its successors or assigns, and by any owner, lessee or tenant of the Parcels of the Property.

Should the City or any owner, lessee or tenant bri ng an action to enforce any of the terms of this Covenant and Agreement, the prevailing party sh all be entitled to costs of suit including reasonable attorneys’ fees.

7. Subject to the prior written appr ov
al of the City by its Public Works
Director, any provision contained herein may be terminated, modified or amended as to all of the Property or any portion thereof. No such te rmination, modification or amendment shall be effective until there shall have been executed, acknowledged and re corded in the Office of the Recorder of Riverside County, Ca lifornia, an appropriate inst rument evidencing the same including the consent thereto by the City.

IN WITNESS WHEREOF, Declarant has caused this Covenant and Agreem ent to
be executed as of the day and year first written above.

___________{Insert_Name_of_Owner}__________

________________________________
Name:

Title:

___________________________________________
Name:

Title:

APPROVED AS TO FORM: APPROVED AS TO CONTENT

________________________________ _______________________________ N a m e : N a m e :

Deputy City Attorney Public Works Department:

PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies

STATE OF )
)

C O U N T Y O F )

On _____________________________, before me, ____________________________, Notary Public, personally appeared _______________________________________________, who proved to m
e on the basis of satisfactory eviden ce, to be the person(s) whose name(s) is/are subscribed to the within instrument and acknowle dged to me that he/she/they executed the same in his/her/their authorized capaci ty(ies), and that by his/her/thei r signature(s) on the instrument the person(s), or the entity upon behalf of which the person(s) acted, executed the instrument.

I certify under PENALTY OF PERJURY under the laws of the State of ______________ that the foregoing paragraph is true and correct.

WITNESS my hand and official seal.

(SEAL)
Notary Public Signature

STATE OF )
)

C O U N T Y O F )

I certify under PENALTY OF PERJURY under the laws of the State of ______________ that the foregoing paragraph is true and correct.

WITNESS my hand and official seal.

(SEAL)
Notary Public Signature

PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies

EXHIBIT A
(Legal Description)
PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies

EXHIBIT B
(Map/Illustration)
PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies - 36 -

Appendix 10: Educational Materials
BMP Fact Sheets, Maintenance Guidelines and Other End-User BMP Information PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies Infiltration Basin TC-11
June 2021 California Stormwater BMP Handbook 5-89
Development
www.casqa.org

Description
An infiltration basin is a relatively large impoundment that is designed to infiltrate stormwater. Infiltration basins use the natural filtering ability of the soil to remove pollutants in stormwater runoff. Infiltration facilities store runoff until it gradually exfiltrates through the soil and eventually into the water table. This practice removes surface flow and associated pollutants through infiltration and can also help recharge groundwater, thus helping to maintain low flows in stream systems. Infiltration basins can be challenging to apply on many sites, however, because of soils requirements. In addition, some studies have shown relatively high failure rates compared with other management practices.

California Experience
Infiltration basins have a long history of use in California, especially in the Central Valley.

Basins located in Fresno were among those initially evaluated in the National Urban Runoff Program and were found to be effective at reducing the volume of runoff, while posing little long-term threat to groundwater quality (EPA, 1983; Schroeder, 1995). Proper siting of these devices is crucial as underscored by the experience of Caltrans in siting two basins in Southern California. The basin with marginal separation from groundwater and soil permeability failed immediately and could never be rehabilitated. The Water Augmentatoin Study (LASGRWC 2010) perfomred in the Los Angeles region showed no negative impact to ground water from infiltrating stormwater through infiltration practices treating stormwater from sites ranging from 0.5 acres to 7.4 acres.

Infiltration basins have been shown to be effective at reducing many of the pollutants regulated by the State and Regional Water Boards. Additionally, the Water Boards have determined that Design Considerations
 Soil for Infiltration
 Slope
 Aesthetics
Targeted
Constituent Removal
Sediment High
Nutrients High
Trash High
Metals High
Bacteria High
Oil and Grease High
Organics High
Flow Control High
PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies Infiltration Basin TC-11
June 2021 California Stormwater BMP Handbook 5-90
Development
www.casqa.org
infiltration basins can qualify as a ”Full Capture System (FCS)1” for trash. Accordingly, in addition to providing general specifications, this fact sheet includes trash-specific information to assist with upgrading either an existing BMP or the design of a planned BMP to meet the FCS definition. See the “Full Trash Capture Compliance” section and “Trash FCS” subsections in this fact sheet for more information.

Advantages
 Provides stormwater treatment and can be designed to meet hydromodification management requirements and the full capture system definition for trash control.  100% reduction in the load discharged to surface waters.  Can achieve pre-development hydrology by infiltrating a significant portion of the average annual rainfall runoff.

Limitations
 Have a high failure rate if soil and subsurface conditions are not suitable.  May not be appropriate for industrial sites or locations where spills may occur.  Infiltration basins require a minimum soil infiltration rate of 0.5 inches/hour, not appropriate at sites with Hydrologic Soil Types C or D.

Performance
As water migrates through porous soil and rock, pollutant attenuation mechanisms include precipitation, sorption, physical filtration, and bacterial degradation (Table 1). Vegetation establishment may improve water quality performance and decrease residence time (i.e., increase water losses). If functioning properly, this approach is presumed to have high removal efficiencies for particulate pollutants and moderate removal of soluble pollutants. Actual pollutant removal in the subsurface would be expected to vary depending upon site-specific soil types. This technology eliminates discharge to surface waters except for the very largest storms; consequently, complete removal of all stormwater constituents can be assumed.

Table 1. Typical pollutant removal for constituents and removal processes Pollutant Typical
Removal
Median Effluent
Concentration1 Removal Processes Treatment
Depth References
Sediment High (90%) 9.9 mg/l Settling, filtration and
sedimentation in top 2
to 8 inches of media.

1.5 feet Geosyntec Consultants and
Wright Water Engineering 2012;
Hatt et al. 2008; Hunt et al.
2012; Li and Davis 2008;
Stander and Borst 2010;
Maniquiz, 2010; Scholes, 2007

1 Full Capture System (FCS): A treatment control, or series of treatment controls, including but not limited to, a multi-benefit projector a low impact development control that traps all particles that are 5 mm or greater, and has a design treatment capacity that is either: a) of not less than the peak flow rate, Q, resulting from a one-year, one-hour, storm in the subdrainage area, or b) appropriately sized to, and designed to carry at least the same flows as, the corresponding storm drain.

PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies Infiltration Basin TC-11
June 2021 California Stormwater BMP Handbook 5-91
Development
www.casqa.org
Pollutant Typical
Removal
Median Effluent
Concentration1 Removal Processes Treatment
Depth References
Metals High TCd: 0.07 µg/L,
TCr: 0.35 µg/L,
TCu: 5.33 µg/L,
TFe: 1027 µg/L,
TPb: 0.19 µg/L,
TNi: 4.53 µg/L,
TZn: 12.0 µg/L
Settling with sediment
and sorption to organic
matter and clay in
media.
2 feet
Geosyntec Consultants and
Wright Water Engineering 2012;
Hsieh and Davis 2005; Hunt et al.
2012; Maniquiz, 2010
Hydro-
carbons
High (90-
97%)
N/A Volatilization, sorption,
and degradation in
mulch layer.
1 foot Hong et al. 2006; Hunt et al.
2012; Barraud et al 1999;
Dierkes and Geiger, 1999;
Mikkelsen et al. 1997; Hong et
al. 2006. Hsieh and Davis 2005;
Pitt et al. 1999
Total
phosphorus
High
(-240% to
99%)

0.240 mg/l Settling with sediment,
sorption to organic
matter and clay in
media, and plant
uptake. Poor removal
efficiency can result
from media containing
high organic matter or
with high background
concentrations of
phosphorus.
2 feet Clark and Pitt 2009; Davis 2007;
Geosyntec Consultants and
Wright Water Engineering 2012;
Hsieh and Davis 2005; Hunt et
al. 2006; Hunt and Lord 2006; Li
et al. 2010; Maniquiz 2010
Total
nitrogen
High (TKN:
-5% to
64%,
Nitrate: 1%
to 80%)
TN: 0.92 mg/l,
TKN: 1.34 mg/l,
NO2,3-N: 0.37
mg/l
Sorption and settling
(TKN), denitrification in
IWS (nitrate), and
plant uptake. Poor
removal efficiency can
result from media
containing high
organic matter.
3 feet Barrett et al. 2013; Clark and Pitt
2009; Geosyntec Consultants
and Wright Water Engineering
2012; Hunt et al. 2006; Hunt et
al. 2012; Kim et al. 2003; Li et al.
2010; Passeport et al. 2009;
Maniquiz, 2010; Winiarski et al.
2006
PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies Infiltration Basin TC-11
June 2021 California Stormwater BMP Handbook 5-92
Development
www.casqa.org
Pollutant Typical
Removal
Median Effluent
Concentration1 Removal Processes Treatment
Depth References
Bacteria High Enterococcus:
235 MPN/ 100
mL, E.coli: 101
MPN/100 mL
Sedimentation,
filtration, sorption,
desiccation, predation,
and photolysis in
mulch layer and
media.
2 feet Geosyntec Consultants and
Wright Water Engineering 2012;
Hathaway et al. 2009; Hathaway
et al. 2011; Hunt and Lord 2006;
Hunt et al. 2008; Hunt et al.
2012; Jones and Hunt 2010
Trash High N/A Filtration 1.5 feet of
media
Barrett et al. 2013
1 Concentrations are based on bioretention performance data. Underlined effluent concentrations were (statistically) significantly lower than influent concentrations, as determined by statistical hypothesis testing on the available sampled data. Effluent concentrations displayed in italics were (statistically) significantly higher than influent concentrations.

Groundwater contamination concerns exists for infiltration basins (Lind and Karro, 1995; Datry et al., 2004; Pitt, 1999) but pollutant concentrations in the soil column have been shown to decrease rapidly with depth (within the first 6 to 18 inches) (Dechesne, M. et al., 2004; Dierkes and Geiger, 1999; Mikkelsen et al., 1997; Datry et al., 2004). However, pollutant concentrations can be of concern as deep as 10 feet, preferential flow pathways are suspected as the means of transport in some geologic settings (Winiarski et al. 2006). These observations warrant a 10 foot minimum between infiltration basin bottom and seasonal high water table.

Trash FCS
The Trash Amendments adopted by the State Water Board in April 2015 provide a performance standard for treatment of stormwater for trash in the form of the definition of FCS, which infiltration basin meets (see Section 5.6.1 for FCS details).

Suitability and Design
The use of infiltration basins may be limited by a number of factors, including type of native soils, climate, and location of groundwater table. Site characteristics, such as excessive slope of the drainage area, fine-grained soil types, and proximate location of the water table and bedrock, can also preclude the use of infiltration basins. The constraints of each site dictate the appropriate siting and footprint. Fundamental infiltration basin design components are as follows:
 Infiltration rate assessed on-site by a licensed geotechnical engineer or soil scientist.  Unsuitable if known soil contamination is present, or if upstream drainage area uses or store chemicals or hazardous materials that could drain to the basin.  10 feet of separation between bottom of the basin and seasonal high water table.

PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies Infiltration Basin TC-11
June 2021 California Stormwater BMP Handbook 5-93
Development
www.casqa.org
 Drainage area that has been fully stabilized, plus use of a pretreatment BMP (e.g. grassed swales, gravity separator) at the entry point to ensure longevity.  10-ft setback from foundations, 100-ft from septic fields and water supply wells, and 50-ft from steep slopes.

Basin design is highly dependent on the constraints of the considered site. Costs will vary in accordance with the design. Table 2 details a number of core construction components and corresponding design considerations.

Table 2. Cost of design components and associated considerations Component Cost Design Consideration
Excavation Requires infiltration rate > 0.5 in/hr. When excavating ensure that subgrade compaction is minimized. Design
for 6 to 18 inches average ponding depth. Basin should
contain entire upstream WQV. After final grading, till the infiltration surface deeply
Without underdrains $2.75–$5.00/ft2
With underdrains $3.90–$6.15/ft2
Soil Media 1.5–4 feet (deeper for better pollutant removal, hydrologic benefits, and rooting depths) at minimum 5
in/hr infiltration. Total phosphorus < 15 ppm, pH 6–8,
CEC > 5 meq/100 g soil. Organic Matter Content < 5%
by weight. 65% sand, 20% sandy loam, and 15%
compost (from vegetation-based feedstock) by volume.

Recommended mix $2.90–$4.30/ft2
With engineered media $3.60–$5.40/ft2
Soil Media Barrier
When incorporating an underdrain, separate media from
native soil with a geotextile layer, 2 to 4 inches of
washed sand (ASTM C-33), followed by 2 inches of
choking stone (ASTM No. 8) over a 1.5 ft envelope of
ASTM No. 57 stone.

Geotextile $0.45/ft2
Washed sand (2-inch layer) $0.20/ft2
No. 8 aggregate (min 2 inches thick) $0.28/ft2
No. 57 stone (1.5 + feet) $2.49/ft2
Hydraulic Restriction Layer
May use hydraulic restriction layer on vertical surfaces to restrict lateral flows to adjacent subgrades, foundations, or utilities.

Filter fabric $0.45/ft2
Clay $0.65/ft2
30-mil liner $0.35/ft2
Concrete barrier $12.00/ft2
PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies Infiltration Basin TC-11
June 2021 California Stormwater BMP Handbook 5-94
Development
www.casqa.org
Subsurface Option (Figure 1)
Excavation, Installation, and Backfill
Concrete Unit

$9.20/ft2
$59.93/ft2
Constructing a subsurface facility includes excavating to depth, installing concrete unit, overdig, and backfill.

Concrete unit height assumed here: 11' 4". Requires
pretreatment BMP to capture trash and debris.

Landscape $0.20–$3.50/ft2
Armor surface with cobble or vegetation. If planted
(optional), install native, deep rooting, and drought
tolerant plants.

Ensure that adequate head is available to operate flow splitter structures (to allow the basin to be offline) without ponding in the splitter structure or creating backwater upstream of the splitter.

Basin invert area should be determined by the equation. Where:

A = Basin invert area (m2)
WQV = water quality volume (m3)
k = 0.5 times the lowest field-measured hydraulic
Conductivity (m/hr)
t = drawdown time (48 hr)
Design Variations
When traditional surface basins are
infeasible because of land
constraints, subsurface extended
detention basin are ideal (Figure 1).

Open space parks (e.g., baseball
fields, etc.) are an example of where
a subsurface infiltration basin is
ideal because the park’s purpose as
a recreational area is not
compromised. Additionally,
recreational areas typical lack large
structures, therefore the issue of
overhead weight over the subsurface
unit is not a concern.

kt
WQVA=
Figure 1. Subsurface design of an infiltration basin, mid-construction.

PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies Infiltration Basin TC-11
June 2021 California Stormwater BMP Handbook 5-95
Development
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Full Trash Capture Compliance
This section provides trash-specific information to assist with upgrading either an existing BMP or the design of a planned BMP to meet the FCS definition. In addition to developing and adopting the Trash Amendments, the State Water Board provides implementation information on its Trash Implementation web page:
https://www.waterboards.ca.gov/water_issues/programs/stormwater/trash_implementation.h tml.

The web page includes information on best management practices or Full Capture Systems, including lists of State-certified Multi-Benefit Trash Treatment Systems. So, when selecting BMPs for trash control, fact sheet users should refer to both this BMP fact sheet and the State Water Board’s Trash Implementation web page.

Design Modifications to Prevent Trash Migration, Sustain Capacity, and Prevent Reduced Functionality
The infiltration basin must be configured to allow trash to enter the system and for trash to remain in the basin until it can be collected and removed. To meet the requirement, inlets must be designed to pass the peak flow produced by the one-year, one-hour design storm or the same flows as the capacity of the inlet storm drain and solids that would be retained by a 5 mm screen or mesh, must remain in the system.

Inlets
There are a multitude of inlet configurations that will allow trash to enter and be captured in an infiltration basin. An open inlet with a forebay is recommended.

Pretreatment
Pretreatment is beneficial to
increase and consolidate trash
capture while managing
maintenance requirements. A
forebay with mortared cobble is one
example of incorporating
pretreatment in the inlet (Figure 2).

This configuration can slow flow
and allow trash and gross solids to
settle out while consolidating at the
edge of the infiltration basin to
make it easier for maintenance
crews to collect and remove.

Figure 2. Example of a forebay as pretreatment for an infiltration basin.

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Trash Containment
Once trash has been captured in an infiltration basin it must be contained so trash does not escape the infiltration basin.

Containment may be provided by
one or more of these features:
 an external design feature or up-
gradient structure designed to
bypass flows exceeding the
region-specific one-year, one-
hour storm event; or
 the BMP having sufficient
capacity to trap particles from
flows exceeding those generated
by the one-year, one-hour storm
event; or
 the BMP having sufficient
capacity to treat either the
design flows or volumes through media filtration or infiltration into native or amended soils; or
 use of a maximum 5 mm mesh screen on all outlets.

Maintenance
A considerable cost concern associated with infiltration practices is the maintenance burden and longevity. If improperly maintained, infiltration basins have a high failure rate. Thus, it may be necessary to replace the basin with a different technology after a relatively short period of time.

To mitigate failure, ensure particulate loading of the stormwater is minimal, or is reduced with an adjacent pretreatment (i.e. vegetated buffer strip). Reducing the particulate loading enables the soils infiltrative capacity to stay high and functional.

Clogged infiltration basins reduced water quality performance but can also enable standing water to become a nuisance due to mosquito breeding. If the basin takes more than 48 hours to drain, then the rock fill should be removed and all dimensions of the basin should be increased by 2 inches to provide a fresh surface for infiltration. To mitigate failure, ensure particulate loading of the stormwater is minimal, or is reduced with an adjacent pretreatment (Figure 2).

Reducing particulate loading enables the soil’s infiltrative capacity to remain high and functional. Table 3 provides maintenance activity details, frequency, and costs.

Table 3. Typical maintenance activities and associated costs and frequency Frequency Cost Activity
Routine Maintenance (required monthly to every 2 years) Remove excess sediment, trash, and debris across the surface, inlet, and outlet. Check for and
stabilize erosion. Pruning and mowing overgrown Routine (small) $7.62/ft2 Figure 3. Example of an outlet with 5 mm screen.

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Frequency Cost Activity
Routine (medium) $1.91/ft2 vegetation that interferes with access, or safety (if applicable).

Routine (large) $1.91/ft2
End of Life Replacement (service life of 20 years) Excavate to the depth of soil media. Test soil for excessive soil contamination of common
stormwater pollutants (e.g. metals, nutrients).

Continue to remove underlying soil if pollutants
exceed standard for contaminated soil. Replace
with clean soil.

Replacement (small) $10.52/ft2
Replacement (medium) $10.17/ft2
Replacement (large) $10.11/ft2
Note: Small System = 500 ft2; Medium System = 2000 ft2; Large System = 4000 ft2 Underlined statement indicates that the activity may be required more frequently than shown in the table to meet the State Water Board maintenance criteria for Multi-Benefit Treatment Systems to be qualified as Full Capture Systems.

Trash FCS
Maintenance to Prevent Trash Migration, Sustain Capacity, and Prevent Reduced Functionality
For Multi-Benefit Treatment Systems to be qualified as Full Capture Systems, the State Water Board requires regular maintenance to maintain adequate trash capture capacity and to ensure that trapped trash does not migrate offsite. Additionally, the State Water Board requires the BMP owner to establish a maintenance schedule based on site-specific factors, including the design trash capacity of the Infiltration Basin Multi-Benefit Trash Treatment System, storm frequency, and estimated or measured trash loading from the drainage area. To meet those criteria, it is likely that the frequency of trash and debris removal will have to be increased above the recommended monthly interval during the wet season to prevent trash from being blown from the BMP or being washed out of the infiltration basin in the subsequent rain events (see Table 3). Depending on the frequency and size of storms, and upstream pollutant characteristics, trash and debris removal can be as frequent as before and after every wet weather event. The optimum maintenance frequency is best determined by site observation over an average water year.

Trash maintenance not only plays a role in the functionality of the infiltration basin but also in the aesthetics and public perception of the infiltration basin (and of all BMPs). Part of maintaining positive perception among the public is the visibility of a well-maintained BMP.

This positive perception can self-perpetuate further support for integrated stormwater management practices and therefore further investment in regular maintenance.

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Schematic

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References and Sources of Additional Information
Brown, W., and T. Schueler. 1997. The Economics of Stormwater BMPs in the Mid-Atlantic Region. Prepared for the Chesapeake Research Consortium, Edgewater, MD, by the Center for Watershed Protection, Ellicott City, MD.

Clark, S.E., and R. Pitt. 2009. Storm-water filter media pollutant retention under aerobic versus anaerobic conditions. Journal of Environmental Engineering 135(5):367–371.

Caltrans, 2002, BMP Retrofit Pilot Program Proposed Final Report, Rpt. CTSW-RT-01-050, California Dept. of Transportation, Sacramento, CA.

Datry, T., F. Malard, J. Gibert. 2004. Dynamics of solutes and dissolved oxygen in shallow urban groundwater below a stormwater infiltration basin. Science of the Total Environment 329: 215– 229.

Davis, A.P. 2007. Field performance of bioretention: Water quality. Environmental Engineering Science 24(8):1048–1063.

Dechesne, M., S. Barraud, J. Bardin. 2004. Spatial distribution of pollution in an urban stormwater infiltration basin Journal of Contaminant Hydrology 72: 189– 205.

Dierkes, C., W. Geiger. 1999. Pollution retention capabilities of roadside soils Water Science & Technology 39: 201-208.

Dorman, T., M. Frey, J. Wright, B. Wardynski, J. Smith, B. Tucker, J. Riverson, A. Teague, and K. Bishop. 2013. San Antonio River Basin Low Impact Development Technical Design Guidance Manual, v1. San Antonio River Authority. San Antonio, TX.

Galli, J. 1992. Analysis of Urban BMP Performance and Longevity in Prince George's County, Maryland. Metropolitan Washington Council of Governments, Washington, DC.

Geosyntec Consultants and Wright Water Engineering. 2012. International Storm Water BMP Database Pollutant Category Summary Statistical Addendum: TSS, Bacteria, Nutrients, and Metals. 2012. International Storm Water BMP Database. http://www.bmpdatabase.org/

Hathaway, J.M., W.F. Hunt, and S.J. Jadlocki. 2009. Indicator bacteria removal in stormwater best management practices in Charlotte, North Carolina. Journal of Environmental Engineering 135(12):1275–1285.

Hathaway, J.M., W.F. Hunt, A.K. Graves, and J.D. Wright. 2011. Field evaluation of bioretention indicator bacteria sequestration in Wilmington, NC. Journal of Environmental Engineering 137(12):1103–1113.

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Hilding, K. 1996. Longevity of infiltration basins assessed in Puget Sound. Watershed Protection Techniques 1(3):124–125.

Hong, E., M. Seagren, and A.P. Davis. 2006. Sustainable oil and grease removal from synthetic stormwater runoff using bench-scale bioretention studies. Water Environment Research. 78(2):141-155.

Hsieh, C.H., and A.P. Davis. 2005. Evaluation and optimization of bioretention media for treatment of urban stormwater runoff. Journal of Environmental Engineering 131(11):1521– 1531.

Hunt, W.F., and W.G. Lord. 2006. Bioretention Performance, Design, Construction, and Maintenance. North Carolina Cooperative Extension, Raleigh, NC.

Hunt, W.F., A.R. Jarrett, J.T. Smith, and L.J. Sharkey. 2006. Evaluating bioretention hydrology and nutrient removal at three field sites in North Carolina. Journal of Irrigation and Drainage Engineering 132(6):600–608.

Hunt, W.F., A.P. Davis, and R.G. Traver. 2012. Meeting hydrologic and water quality goals through targeted bioretention design. Journal of Environmental Engineering 138(6):698–707.

Jones, M.P., and W.F. Hunt. 2010. Effect of stormwater wetlands and wet ponds on runoff temperature in trout sensitive waters. Journal of Irrigation and Drainage Engineering 136(9):656–661.

Kim, H., E.A. Seagren, and A.P. Davis. 2003. Engineered bioretention for removal of nitrate from stormwater runoff. Water Environment Research 75(4):355–367.

Li, M.-H., C.Y. Sung, M.H. Kim, and K.-H. Chu. 2010. Bioretention for Stormwater Quality Improvements in Texas: Pilot Experiments. Texas A&M University in cooperation with Texas Department of Transportation and the Federal Highway Administration.

Li, H., and A.P. Davis. 2008. Urban particle capture in bioretention media. I: Laboratory and field studies. Journal of Environmental Engineering 143(6):409–418.

Lind, B. B., Karro, E. 1995. “Stormwater infiltration and accumulation of heavy metals in roadside green areas in Göteborg, Sweden,” Ecological Engineering, 5, 533-539.

Maniquiz, M., S. Lee, L. Kim. 2010. Long-Term Monitoring Of Infiltration for Nonpoint Source Pollution Control. Water, Air, & Soil Pollution. 212(1):13-26 Maryland Department of the Environment (MDE). 2000. Maryland Stormwater Design Manual. http://www.mde.state.md.us/environment/wma/stormwatermanual . Accessed May
22, 2002.

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Mikkelsen, P., Häfliger, M., Ochs, M., Jacobsen, P., Tjell, J. 1997. Pollution of soil and groundwater from infiltration of highly contaminated stormwater-a case study. Water Science & Technology, 36, 325-330.

Nightingale, H.I., 1975, “Lead, Zinc, and Copper in Soils of Urban Storm-Runoff Retention Basins,” American Water Works Assoc. Journal. Vol. 67, p. 443-446.

Nightingale, H.I., 1987a, “Water Quality beneath Urban Runoff Water Management Basins,” Water Resources Bulletin, Vol. 23, p. 197-205.

Nightingale, H.I., 1987b, “Accumulation of As, Ni, Cu, and Pb in Retention and Recharge Basin Soils from Urban Runoff,” Water Resources Bulletin, Vol. 23, p. 663-672.

Nightingale, H.I., 1987c, “Organic Pollutants in Soils of Retention/Recharge Basins Receiving Urban Runoff Water,” Soil Science Vol. 148, pp. 39-45.

Nightingale, H.I., Harrison, D., and Salo, J.E., 1985, “An Evaluation Technique for Ground- water Quality Beneath Urban Runoff Retention and Percolation Basins,” Ground Water Monitoring Review, Vol. 5, No. 1, pp. 43-50.

Oberts, G. 1994. Performance of Stormwater Ponds and Wetlands in Winter. Watershed Protection Techniques 1(2): 64–68.

Passeport, E., W.F. Hunt, D.E. Line, R.A. Smith, and R.A. Brown. 2009. Field study of the ability of two grassed bioretention cells to reduce stormwater runoff pollution. Journal of Irrigation and Drainage Engineering 135(4):505–510. Ramsey, C.G. & H. R. Sleeper. 1988. Architectural Graphic Standards (Eighth Ed.), Somerset, NJ: John Wiley & Sons.

Pitt, R., Clark, S., Field, R. 1999. Groundwater contamination potential from stormwater infiltration practices. Urban Water, 1:217-236
Scholes, L. M. Revitt, J. Ellis. 2007. A systematic approach for the comparative assessment of stormwater pollutant removal potentials. Journal of Environmental Management, 88(2008):
467–478.

Schueler, T. 1987. Controlling Urban Runoff: A Practical Manual for Planning and Designing Urban BMPs. Metropolitan Washington Council of Governments, Washington, DC.

Schroeder, R.A., 1995, Potential For Chemical Transport Beneath a Storm-Runoff Recharge (Retention) Basin for an Industrial Catchment in Fresno, CA, USGS Water-Resource Investigations Report 93-4140.

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Southeastern Wisconsin Regional Planning Commission (SWRPC). 1991. Costs of Urban Nonpoint Source Water Pollution Control Measures. Southeastern Wisconsin Regional Planning Commission, Waukesha, WI.

Tetra Tech (Tetra Tech, Inc.). 2014. Low Impact Development Handbook Stormwater Management Strategies County of San Diego Department of Public Works by Tetra Tech, Inc., San Diego, CA.

U.S. EPA, 1983, Results of the Nationwide Urban Runoff Program: Volume 1 – Final Report, WH-554, Water Planning Division, Washington, DC.

Watershed Management Institute (WMI). 1997. Operation, Maintenance, and Management of Stormwater Management Systems. Prepared for U.S. Environmental Protection Agency Office of Water, Washington, DC.

Winer, R. 2000. National Pollutant Removal Database for Stormwater Treatment Practices (2 nd
edition). Ellicott City: Center for Watershed Protection.

Winiarski, T., J. Bedell, C. Delolme, Y. Perrodin. 2006. The impact of stormwater on a soil profile in an infiltration basin. Hydrogeology Journal 14: 1244–1251.

Information Resources
Center for Watershed Protection (CWP). 1997. Stormwater BMP Design Supplement for Cold Climates. Prepared for U.S. Environmental Protection Agency Office of Wetlands, Oceans and Watersheds. Washington, DC.

Ferguson, B.K., 1994. Stormwater Infiltration. CRC Press, Ann Arbor, MI.

Los Angeles and San Gabriel Rivers Watershed Council (LASGRWC). 2010. Water Augmentation Study, Research, Strategy, and implementation Report. http://lasgrwc2.org/dataandreference/Document.aspx?search=48 USEPA. 1993. Guidance to Specify Management Measures for Sources of Nonpoint Pollution in Coastal Waters. EPA-840-B-92-002. U.S. Environmental Protection Agency, Office of Water, Washington, DC.

PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies Site Design & Landscape Planning SD-10
Description
Design Objectives
@ Maximize Infiltration
@ Provide Retention
@ Slow Runoff
@ Minimize Impervious Land
Coverage
Prohibit Dumping of Improper
Materials
Contain Pollutants
Collect and Convey
Each project site possesses unique topographic, hydrologic, and vegetative features, some of which are more suitable for development than others. Integrating and incorporating appropriate landscape planning methodologies into the project design is the most effective action that can be done to minimize surface and groundwater contamination from stormwater.

Approach
Landscape planning should couple consideration of land suitability for urban uses with consideration of community goals and projected growth. Project plan designs should conserve natural areas to the extent possible, maximize natural water storage and infiltration opportunities, and protect slopes and channels.

Suitable Applications
Appropriate applications include residential, commercial and industrial areas planned for development or redevelopment.

Design Considerations
Design requirements for site design and landscapes planning should conform to applicable standards and specifications of agencies with jurisdiction and be consistent with applicable General Plan and Local Area Plan policies.

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Designing New Installations
Begin the development of a plan for the landscape unit with attention to the following general principles:
■ Formulate the plan on the basis of clearly articulated community goals. Carefully identify conflicts and choices between retaining and protecting desired resources and community growth.
■ Map and assess land suitability for urban uses. Include the following landscape features in the assessment: wooded land, open unwooded land, steep slopes, erosion-prone soils, foundation suitability, soil suitability for waste disposal, aquifers, aquifer recharge areas, wetlands, floodplains, surface waters, agricultural lands, and various categories of urban land use. When appropriate, the assessment can highlight outstanding local or regional resources that the community determines should be protected (e.g., a scenic area, recreational area, threatened species habitat, farmland, fish run). Mapping and assessment should recognize not only these resources but also additional areas needed for their sustenance.

Project plan designs should conserve natural areas to the extent possible, maximize natural water storage and infiltration opportunities, and protect slopes and channels.

Conserve Natural Areas during Landscape Planning
If applicable, the following items are required and must be implemented in the site layout during the subdivision design and approval process, consistent with applicable General Plan and Local Area Plan policies:
■ Cluster development on least-sensitive portions of a site while leaving the remaining land in a natural undisturbed condition.
■ Limit clearing and grading of native vegetation at a site to the minimum amount needed to build lots, allow access, and provide fire protection.
■ Maximize trees and other vegetation at each site by planting additional vegetation, clustering tree areas, and promoting the use of native and/ or drought tolerant plants. ■ Promote natural vegetation by using parking lot islands and other landscaped areas. ■ Preserve riparian areas and wetlands.

Maximize Natural Water Storage and Infiltration Opportunities Within the Landscape Unit ■ Promote the conservation of forest cover. Building on land that is already deforested affects basin hydrology to a lesser extent than converting forested land. Loss of forest cover reduces interception storage, detention in the organic forest floor layer, and water losses by evapotranspiration, resulting in large peak runoff increases and either their negative effects or the expense of countering them with structural solutions. ■ Maintain natural storage reservoirs and drainage corridors, including depressions, areas of permeable soils, swales, and intermittent streams. Develop and implement policies and 2 of 4 California Stormwater BMP Handbook
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PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies Site Design & Landscape Planning SD-10
regulations to discourage the clearing, filling, and channelization of these features. Utilize them in drainage networks in preference to pipes, culverts, and engineered ditches. ■ Evaluating infiltration opportunities by referring to the stormwater management manual for the jurisdiction and pay particular attention to the selection criteria for avoiding groundwater contamination, poor soils, and hydrogeological conditions that cause these facilities to fail. If necessary, locate developments with large amounts of impervious surfaces or a potential to produce relatively contaminated runoff away from groundwater recharge areas.

Protection of Slopes and Channels during Landscape Design ■ Convey runoff safely from the tops of slopes.
■ Avoid disturbing steep or unstable slopes.
■ Avoid disturbing natural channels.
■ Stabilize disturbed slopes as quickly as possible.
■ Vegetate slopes with native or drought tolerant vegetation. ■ Control and treat flows in landscaping and/ or other controls prior to reaching existing natural drainage systems.
■ Stabilize temporary and permanent channel crossings as quickly as possible, and ensure that increases in run-off velocity and frequency caused by the project do not erode the channel. ■ Install energy dissipaters, such as riprap, at the outlets of new storm drains, culverts, conduits, or channels that enter unlined channels in accordance with applicable specifications to minimize erosion. Energy dissipaters shall be installed in such a way as to minimize impacts to receiving waters.
■ Line on-site conveyance channels where appropriate, to reduce erosion caused by increased flow velocity due to increases in tributary impervious area. The first choice for linings should be grass or some other vegetative surface, since these materials not only reduce runoff velocities, but also provide water quality benefits from filtration and infiltration. If velocities in the channel are high enough to erode grass or other vegetative linings, riprap, concrete, soil cement, or geo-grid stabilization are other alternatives. ■ Consider other design principles that are comparable and equally effective.

Redeveloping Existing Installations
Various jurisdictional stormwater management and mitigation plans (SUSMP, WQMP, etc.) define "redevelopment" in terms of amounts of additional impervious area, increases in gross floor area and/ or exterior construction, and land disturbing activities with structural or impervious surfaces. The definition of" redevelopment" must be consulted to determine whether or not the requirements for new development apply to areas intended for redevelopment. If the definition applies, the steps outlined under "designing new installations" above should be followed.

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PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies SD-10 Site Design & Landscape Planning
Redevelopment may present significant opportunity to add features which had not previously been implemented. Examples include incorporation of depressions, areas of permeable soils, and swales in newly redeveloped areas. While some site constraints may exist due to the status of already existing infrastructure, opportunities should not be missed to maximize infiltration, slow runoff, reduce impervious areas, disconnect directly connected impervious areas.

Other Resources
A Manual for the Standard Urban Stormwater Mitigation Plan (SUSMP), Los Angeles County Department of Public Works, May 2002.

Stormwater Management Manual for Western Washington, Washington State Department of Ecology, August 2001.

Model Standard Urban Storm Water Mitigation Plan (SUSMP) for San Diego County, Port of San Diego, and Cities in San Diego County, February 14, 2002.

Model Water Quality Management Plan (WQMP) for County of Orange, Orange County Flood Control District, and the Incorporated Cities of Orange County, Draft February 2003.

Ventura Countywide Technical Guidance Manual for Stormwater Quality Control Measures, July 2002.
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PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies Roof Runoff Controls
Rain Garden
Description
Various roof runoff controls are available to address stormwater SD-11
Design Objectives
0 Maximize Infiltration
0 Provide Retention
0 Slow Runoff
Minimize Impervious Land
Coverage
Prohibit Dumping of Improper
Materials
0 Contain Pollutants
Collect and Convey
that drains off rooftops. The objective is to reduce the total volume and rate of runoff from individual lots, and retain the pollutants on site that may be picked up from roofing materials and atmospheric deposition. Roof runoff controls consist of directing the roof runoff away from paved areas and mitigating flow to the storm drain system through one of several general approaches: cisterns or rain barrels; dry wells or infiltration trenches; pop-up emitters, and foundation planting. The first three approaches require the roof runoff to be contained in a gutter and downspout system. Foundation planting provides a vegetated strip under the drip line of the roof.

Approach
Design of individual lots for single-family homes as well as lots for higher density residential and commercial structures should consider site design provisions for containing and infiltrating roof runoff or directing roof runoff to vegetative swales or buffer areas. Retained water can be reused for watering gardens, lawns, and trees. Benefits to the environment include reduced demand for potable water used for irrigation, improved stormwater quality, increased groundwater recharge, decreased runoff volume and peak flows, and decreased flooding potential.

Suitable Applications
Appropriate applications include residential, commercial and industrial areas planned for development or redevelopment.

Design Considerations
Designing New Installations
Cisterns or Rain Barrels
One method of addressing roof runoff is to direct roof downspouts to cisterns or rain barrels. A cistern is an above ground storage vessel with either a manually operated valve or a permanently open outlet. Roof runoff is temporarily stored and then released for irrigation or infiltration between storms. The number of rain January 2003 California Stormwater BMP Handbook
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PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies SD-11 Roof Runoff Controls
barrels needed is a function of the rooftop area. Some low impact developers recommend that every house have at least 2 rain barrels, with a minimum storage capacity of 1000 liters. Roof barrels serve several purposes including mitigating the first flush from the roof which has a high volume, amount of contaminants, and thermal load. Several types of rain barrels are commercially available. Consideration must be given to selecting rain barrels that are vector proof and childproof. In addition, some barrels are designed with a bypass valve that filters out grit and other contaminants and routes overflow to a soak-away pit or rain garden.

If the cistern has an operable valve, the valve can be closed to store stormwater for irrigation or infiltration between storms. This system requires continual monitoring by the resident or grounds crews, but provides greater flexibility in water storage and metering. If a cistern is provided with an operable valve and water is stored inside for long periods, the cistern must be covered to prevent mosquitoes from breeding.

A cistern system with a permanently open outlet can also provide for metering stormwater runoff. If the cistern outlet is significantly smaller than the size of the downspout inlet (say ¼ to ½ inch diameter), runoff will build up inside the cistern during storms, and will empty out slowly after peak intensities subside. This is a feasible way to mitigate the peak flow increases caused by rooftop impervious land coverage, especially for the frequent, small storms.

Dry wells and Infiltration Trenches
Roof downspouts can be directed to dry wells or infiltration trenches. A dry well is constructed by excavating a hole in the ground and filling it with an open graded aggregate, and allowing the water to fill the dry well and infiltrate after the storm event. An underground connection from the downspout conveys water into the dry well, allowing it to be stored in the voids. To minimize sedimentation from lateral soil movement, the sides and top of the stone storage matrix can be wrapped in a permeable filter fabric, though the bottom may remain open. A perforated observation pipe can be inserted vertically into the dry well to allow for inspection and maintenance.

In practice, dry wells receiving runoff from single roof downspouts have been successful over long periods because they contain very little sediment. They must be sized according to the amount of rooftop runoff received, but are typically 4 to 5 feet square, and 2 to 3 feet deep, with a minimum of 1-foot soil cover over the top (maximum depth of 10 feet).

To protect the foundation, dry wells must be set away from the building at least 10 feet. They must be installed in solids that accommodate infiltration. In poorly drained soils, dry wells have very limited feasibility.

Infiltration trenches function in a similar manner and would be particularly effective for larger roof areas. An infiltration trench is a long, narrow, rock-filled trench with no outlet that receives stormwater runoff. These are described under Treatment Controls.

Pop-up Drainage Emitter
Roof downspouts can be directed to an underground pipe that daylights some distance from the building foundation, releasing the roof runoff through a pop-up emitter. Similar to a pop-up irrigation head, the emitter only opens when there is flow from the roof. The emitter remains flush to the ground during dry periods, for ease of lawn or landscape maintenance. 2 of 3 California Stormwater BMP Handbook
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PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies Roof Runoff Controls SD-11
Foundation Planting
Landscape planting can be provided around the base to allow increased opportunities for stormwater infiltration and protect the soil from erosion caused by concentrated sheet flow coming off the roof. Foundation plantings can reduce the physical impact of water on the soil and provide a subsurface matrix of roots that encourage infiltration . These plantings must be sturdy enough to tolerate the heavy runoff sheet flows, and periodic soil saturation.

Redeveloping Existing Installations
Various jurisdictional stormwater management and mitigation plans (SUSMP, WQMP, etc.) define "redevelopment" in terms of amounts of additional impervious area, increases in gross floor area and/ or exterior construction, and land disturbing activities with structural or impervious surfaces. The definition of" redevelopment" must be consulted to determine whether or not the requirements for new development apply to areas intended for redevelopment . If the definition applies, the steps outlined under "designing new installations" above should be followed.

Supplemental Information
Examples
■ City of Ottawa's Water Links Surface -Water Quality Protection Program ■ City of Toronto Downspout Disconnection Program
■ City of Boston, MA, Rain Barrel Demonstration Program Other Resources
Hager, Marty Catherine, Stormwater, "Low-Impact Development", January/February 2003 . www.stormh2o .com
Low Impact Urban Design Tools, Low Impact Development Design Center, Beltsville, MD. www.lid-stormwater.net
Start at the Source, Bay Area Stormwater Management Agencies Association, 1999 Edition January 2003 California Stormwater BMP Handbook
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PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies Efficient Irrigation SD-12
Design Objectives
0 Maximize Infiltration
0 Provide Retention
0 Slow Runoff
Minimize Impervious Land
Coverage
Prohibit Dumping of Improper
Materials
Description
Contain Pollutants
Collect and Convey
Irrigation water provided to landscaped areas may result in excess irrigation water being conveyed into stormwater drainage systems.

Approach
Project plan designs for development and redevelopment should include application methods of irrigation water that minimize runoff of excess irrigation water into the stormwater conveyance system.

Suitable Applications
Appropriate applications include residential, commercial and industrial areas planned for development or redevelopment. (Detached residential single-family homes are typically excluded from this requirement.)
Design Considerations
Designing New Installations
The following methods to reduce excessive irrigation runoff should be considered, and incorporated and implemented where determined applicable and feasible by the Permittee:
■ Employ rain-triggered shutoff devices to prevent irrigation after precipitation. ■ Design irrigation systems to each landscape area's specific water requirements. ■ Include design featuring flow reducers or shutoff valves triggered by a pressure drop to control water loss in the event of broken sprinkler heads or lines.
■ Implement landscape plans consistent with County or City water conservation resolutions, which may include provision of water sensors, programmable irrigation times (for short cycles), etc.

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PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies SD-12 Efficient Irrigation
■ Design timing and application methods of irrigation water to minimize the runoff of excess irrigation water into the storm water drainage system.
■ Group plants with similar water requirements in order to reduce excess irrigation runoff and promote surface filtration. Choose plants with low irrigation requirements (for example, native or drought tolerant species). Consider design features such as:

Using mulches (such as wood chips or bar) in planter areas without ground cover to minimize sediment in runoff
Installing appropriate plant materials for the location, in accordance with amount of sunlight and climate, and use native plant materials where possible and/ or as recommended by the landscape architect
Leaving a vegetative barrier along the property boundary and interior watercourses, to act as a pollutant filter, where appropriate and feasible Choosing plants that minimize or eliminate the use of fertilizer or pesticides to sustain growth
■ Employ other comparable, equally effective methods to reduce irrigation water runoff.

Other Resources
A Manual for the Standard Urban Stormwater Mitigation Plan (SUSMP), Los Angeles County Department of Public Works, May 2002.

Model Standard Urban Storm Water Mitigation Plan (SUSMP) for San Diego County, Port of San Diego, and Cities in San Diego County, February 14, 2002.

Model Water Quality Management Plan (WQMP) for County of Orange, Orange County Flood Control District, and the Incorporated Cities of Orange County, Draft February 2003.

Ventura Countywide Technical Guidance Manual for Stormwater Quality Control Measures, July 2002.
2 of 2 California Stormwater BMP Handbook
New Development and Redevelopment
www.cabmphandbooks.com
January 2003
PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies

Riverside City CouncilApril 22, 2025

Riverside City Council
April 22, 2025