cc 2022 AR 11/15 camino largo residential development p21-0300 — Vista City Council, November 15, 2022 (part 6 of 8)

11 /15/2022 PH 1 Page 840 of 1307

POC-1
There is one (1) biofiltration basin which will outlet into an existing storm drain along -side North Santa Fe Avenue south of Camino Largo and discharge from the site at POC-1.

POC-2
There is one (1) biofiltration basin which outlets via a storm drain into a natural swale at POC-2.

Additional offsite areas along the easterly boundary and towards the northeast is diverted around the development via drainage channels and rip rap, to discharge as historically over Camino Largo and sheet flow into a natural swale.

DISP-1 and DMIN-1
Project frontage street improvements include North Santa Fe street widening delineated by DISP-1 and DMIN-1. North Santa Fe cross section is in a full superelevation cross section, 4% sloping away from the project frontage in a southeasterly direction. Therefore it is infeasible to provide any stormwater treatment or flow control without the ultimate street improvements being completed. However, the proposed sidewalk along the project frontage will be non-contiguous with the proposed curb and gutter, allowing impervious dispersion to occur effectively disconnecting the concrete sidewalk from directly draining offsite by routing runoff from the sidewalk onto the adjacent landscape areas.

Camino Largo
Project frontage street improvements include Camino Largo street widening delineated on the DMA Exhibit. Camino Largo will be improved to the centerline and another 12 feet to the south of the centerline, except where the crown of Camino Largo has been transition to the south 8 feet between Private Street — Lot F and the spillway to prevent street runoff from overflowing to the south and bypassing the BMP 2. A proposed 8 inch curb and gutter will be used between the previously mentioned crown transition to sufficiently convey street runoff into BMP 2.

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11 /15/2022 PH 1 Page 841 of 1307

FORM 6 — STORMWATER BMP MAINTENANCE MECHANISM

PROJECT IDENTIFICATION
Project Name: Camino Largo
Permit Application Number: P21-0300
Maintenance Requirements
A stormwater structural BMP operations and maintenance plan must be prepared for PDPs. A template plan is available at:
http://www.cityofvista.com/services/city-departments/community-development/building-planning- permits-applications/land-development-autocad-templates/storm-water-forms Has a stormwater structural BMP operations and maintenance plan been prepared? ❑X Yes, included with Attachment 3A
❑ No
bhA. Inc
land planning, civil engineering, surveying
5115 Avenida Encinas, Suite L
Carlsbad, CA 92008-4387
(760) 931-8700
[INSERT PREPARER'S TITLE/COMPANY]
All projects are required to maintain designed functionality of structural BMPs in perpetuity. Privately - owned projects must record a Storm Drain Maintenance Agreement with the County of San Diego Assessor's Office. A template Storm Drain Maintenance Agreement is available at:
http://www.cityofvista.com/services/city-departments/community-development/building-planning- permits-applications/land-development-autocad-templates/storm-water-forms Has a Storm Drain Maintenance Agreement been submitted to the County? ❑X Yes, copy included with Attachment 3B
❑ No
❑ Not Applicable (e.g., city -owned property/project)

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11 /15/2022 PH 1 Page 842 of 1307

Each of the attachments indicated below should be considered for inclusion with the SWQMP. Use this ATTACHMENT 1— POLLUTANT CONTROLS: SUPPORT DOCUMENT AND

CHECKLIST
checklist to indicate which attachments are included behind this coversheet.

Attachment
Contents
Checklist
Sequence
Attachment 1A
Drainage Management Area (DMA)
❑X Included
Exhibit
See DMA Exhibit Checklist on next page.

Attachment 1B
Tabular Summary of DMAs Showing
❑X Included on DMA Exhibit in Attachment 1A
DMA ID matching DMA Exhibit, DMA
Area, DMA Type, and BMPs*
❑ Included as Attachment 113
*Provide table in this Attachment OR on
DMA Exhibit in Attachment 1A
Attachment 1C
Harvest and Use Feasibility Screening
❑X Included
Checklist (Worksheet B.3-1)
❑ Not included because the entire project
Refer to Appendix B.3-1 of the BMP
will use Infiltration BMPs
Design Manual.

Attachment 1D
Categorization of Infiltration Feasibility
❑X Included
Condition (Worksheet C.4-1)
❑ Not included because the entire project
Refer to Appendices C and D of the BMP
will use Harvest and Use BMPs
Design Manual.

Attachment 1E
Pollutant Control BMP Design
❑X Included
Worksheets and Calculations
Refer to Appendices B and E of the BMP
Design Manual for structural pollutant
control BMP design guidelines

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11 /15/2022 PH 1 Page 843 of 1307

ATTACHMENT 1A — DMA EXHIBIT CHECKLIST
For Attachment 1A, provide map(s) for the project site, titled "DMA Exhibit." The checklist below identifies minimum elements that must be included with the DMA Exhibit. 0 Underlying hydrologic soil group
❑%� Approximate depth to groundwater
0 Existing natural hydrologic features (watercourses, seeps, springs, wetlands, etc.) 0 Critical coarse sediment yield areas to be protected
❑%� Existing topography and impervious areas
0 Existing and proposed site drainage network and storm drain structures 0 Proposed connections to offsite drainage
0 Proposed demolition
❑%� Proposed grading
0 Proposed impervious features
0 Proposed design features and surface treatments used to minimize imperviousness 0 Drainage management area (DMA) boundaries
DMA identification numbers (DMA ID)
0 DMA areas (square footage or acreage)
0 DMA type (Drains to BMP, Self -mitigating, De Minimis, or Self -retaining) 0 Potential pollutant source areas and corresponding required source controls (see Form 2 and Form 3 of SWQMP, BMP Design Manual Chapter 4 and Appendix E.1) 0 Proposed Structural BMPs (see Form 5 of SWQMP)

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11 /15/2022 PH 1 Page 844 of 1307

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TYPE G-2 CATCH BASIN
PER D-8

OUTFLOW
THREE (3) 12" RCP I I 1 1 1 1 1 I

OUTLET PIPES
30 ML

IMPERMEABLE
LINER* EXIST. GROUND
n
X
3" MULCH

DEEP ROUTED, DENSE,

DROUGHT TOLERANT

PLANTING SUITABLE FOR

WELL DRAINED SOIL
18" AMENDED SOIL MIN. INFILTRATION RATE 5"/HR
LEGEND
FREEBOARD = 12.00" (CONJUNCTIVE USE FACILITY)
O BASIN HEIGHT HMAX = 30.00"
' O3 PONDING DEPTH = 6.00"
— I
11'O RISER INVERT HTOP = 18.00"
_ 4" PEA GRAVEL
O5 *EMERGENCY WEIR INVERT = 18.00"
U R 7" GRAVEL LAYER O *LOWER SLOT INVERT = 6.00"
FOR V2 STORAGE 1 - 5" HIGH X 34" LONG OPENING
o _
7O *UPPER SLOT INVERT = 7.00"
6" PERFORATED PVC PIPE 1 - 4" HIGH X 10" LONG OPENING
III — i CONFORMING TO ASTM D PC POLLUTANT CONTROL WSEL = 6.00" 3034 OR EQUIVALENT
RESTRICTER CAP TO LIMIT FLOW 3" DEAD STORAGE HC HYDROMODIFICATION CONTROL WSEL = 13.92" OUT OF V2 STORAGE AREA, LID BELOW UNDERDRAIN
DRAIN DOWN HOLE, d = 4.00" FC FLOOD CONTROL WSEL = 18.00" BIOFILTRATION BASIN DETAIL, BMP 1

NOT TO SCALE
*30 MILLINER NOTE: 30-MIL IMPERMEABLE LINER FOR BIORETENTION CONFORM TO THE FOLLOWING SPECIFICATIONS: SPECIFIC GRAVITY (ASTM D792): 1.2 (G/CC, MIN.); TENSILE (ASTM D882): 73 (LB/IN-WIDTH, MIN); ELONGATION AT BREAK (ASTM D882): 380 (%, MIN); MODULUS (ASTM D882):
30 (LB/IN-WIDTH, MIN.); AND TEAR STRENGTH (ASTM D1004): 8 (LB/IN, MIN); SEAM SHEAR STRENGTH (ASTM D882) 58.4 (LB/IN, MIN); SEAM PEEL STRENGTH (ASTM D882) 15 (LB/IN, IN).

SEE COLORADO LINING INTERNATIONAL PVC 30
HTTP: //WWW.COLORADOLINING.COM/PRODUCTS/PVC.PDF) OR APPROVED EQUAL. 0 OUTFLOW
TWO (2) 12" RCP

OUTLET PIPES
30 ML

IMPERMEABLE
LINER*
TYPE G-1 CATCH BASIN
PER D-8

II III III
EXIST. GROUND
9 3" MULC

DEEP ROUTED, DENSE,

DROUGHT TOLERANT

PLANTING SUITABLE FOR

WELL DRAINED SOIL
18" AMENDED SOIL MIN. INFILTRATION RATE 5"/HR

RESTRICTER CAP TO LIMIT FLOW
OUT OF V2 STORAGE AREA, LID
DRAIN DOWN HOLE, d = 3.00"
W.
—I
144" PEA GRAVEL
=1
7" GRAVEL LAYER
FOR V2 STORAGE
I'
6" PERFORATED PVC PIPE
i CONFORMING TO ASTM D
3034 OR EQUIVALENT
3" DEAD STORAGE

BELOW UNDERDRAIN
BIOFILTRATION BASIN DETAIL, BMP 2

SEE COLORADO LINING INTERNATIONAL PVC 30
HTTP: //WWW.COLORADOLINING.COM/PRODUCTS/PVC.PDF) OR APPROVED EQUAL.

MALE NATIONAL PIPE THREAD

PVC ADAPTER CAST

IN SIDE OF RISER WALL
/- RISER WALL
*ELEVATION MEASURED FROM BASIN SURFACE
LEGEND
10 FREEBOARD =

12.00" (CONJUNCTIVE USE FACILITY)
O2 BASIN HEIGHT
HMAx = 30.00"
O3 PONDING DEPTH = 6.00"

O RISER INVERT
HTOP = 18.00"
O5 *EMERGENCY WEIR INVERT = 18.00"
O *LOWER SLOT
INVERT = 6.00"
1 - 3" HIGH
X 32" LONG OPENING
7O *UPPER SLOT
INVERT = 7.00"
1 - 2" HIGH
X 6" LONG OPENING
PC POLLUTANT CONTROL WSEL = 6.00"
HC HYDROMODIFICATION CONTROL WSEL = 6"
FC FLOOD CONTROL WSEL = 18.00"
*ELEVATION MEASURED FROM BASIN SURFACE
a rAB ORS LAYER
UNDERDRAIN ORIFICE a

THREADED FEMALE NATIONAL

PIPE THREAD PVC CAP
WITH DRILLED ORIFICE 6" FRENCH DRAIN,
PL IN IN IN -i _�)(ERFORATED PVC PIPE bhA,
inc,
d °QG Dafnd pDaPl�Whg, dA enghesdIngo surveyhg
III=1 I I i 11-1 11-
11 —III—III 5115 AVENIDA ENCINAS
SUITE "L"
BOTTOM OF BASIN CARLSBAD, CA. 92008-4387
(760) 931-8700
- d d
a
a
d d d a d C
a ° Q
a
a
d Q
6" PERFORATED PVC PIPEUNDERDRAIN ORIFICE d DMA EXHIBIT
THREADED FEMALE NATIONAL 'a °
PIPE THREAD PVC CAP a d a a CAMINO LARGO
WITH DRILLED ORIFICE a d
a
RESTRICTOR CAP DETAIL BMP 1 & 2

NOT TO SCALE
K:\Cililf\6ti�bg'�G\SWMP\DMA-TSM.dwg, 12/7/2021 11:44:58AM PH1 Page 846 of 1307

ATTACHMENT 1C — HARVEST AND USE FEASIBILITY SCREENING
CHECKLIST (WORKSHEET B.3-1)

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11 /15/2022 PH 1 Page 847 of 1307

Appendix B. Storm Water Pollutant Control Hydrologic Calculations and Sizing Methods Workshect B.3-1. Harvest and Use Feasibility Screening

1. Is there a demand for harvested water (check all that apply) at the project site that is reliably present during the wet season?
❑ Toilet and umal flushing
® Landscape irrigation
❑ Other:

2. If there is a demand, estimate the anticipated average wet season demand over a period of 36 hours.

Guidance for plarut ng level demand calculations for toilet/urinal flushing and landscape irrigation is provided in Section B.3.2.

Modified ETWU = 2.7 x [[(0.2 )<180,518)I0.9] x 0.015] = 1,625 cf Total Previous Area = 180,518 sf

3. Calculate the DCV using worksheet B-2,1,
DCV = 7,329+4,899=12,228 of
3a. Is the 36-hour demand
3b. Is the 36-hour demand greater
3c. Is the 36-hour
greater than or equal to the
than 0.25DCV but less than the full
demand less than
DCV?
DCV?

0.25DCV?
/ IVo a
/ ��
Yes
Yes
yes
Harvest and use appears to be
Harvest and use may be feasible.

Harvest and use is
feasible. Conduct more detailed
Conduct more detailed evaluation and
considered to be
evaluation and sizing
sizing calculations to deterniute
infeasible.
calculations to confirm that
feasibility. Harvest and use may only
DCV can be used at an adequate
be able to be used for a portion of the
rate to meet drawdown criteria,
site, or (optionally) the storage may
need to be upsizcd to meet long term
capture targets while draining in
longer than 36 hours.

B-11 February 2016

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11 /15/2022 PH 1 Page 848 of 1307

ATTACHMENT 113— CATEGORIZATION OF INFILTRATION FEASIBILITY J013 0 16-190.5
Storm Water5MP
a :; (;
Test Site Location-
Percolation Data
Camino Largo,
Vista
Intltratlon BMPType
Infiltration Basin
Test Method
Shallow Percolation Testing (Option 2)
Factor of Safety
FS=3
Drflf Date
08/10/16
Test Date
0&11I16
Equipment Type
B-31 Mobile Drill Using Said stem Auger
Tesl Bore Diameter
8' inch
Observation Bore Diameter
6' Inch
Groundwater Conditions
Groundwater Encountered 13' 5' In Deep B
Wcathar Conditions
Dry, Sunny, 813° to 90' F
Test No. I Depth ft
Percolation Rate rn 1 Infiltration Rate in hr
1 4'
2fl.00 0.16

BAISN A
la 4'

10.00 0.31
2 4'

15.00 0.23

BASIN G
2a 4'

12.U0 D.29
3 4'

30.00 0.104

BASIN B
3a 4'

34.00 0.101

BAISN A
Aywtiye = 15.00 mpi Average = 0.24 inlhr

BASIN G
Average = 13-60 mpi Average = 0,26 inlhr

BASIN B
Average = 32.00 mpi Average =0.103 inlhr
Infiltration Rales Vary 511ghtly Due to Actual Depth of Hole In Inches Depth k
Observation Dori 9 A 00016
No Groundwater Encaunrered
Clean Depth = 20' 1"
Da h ft
Observation Boring 8 0811012018
0 - 3' Tan Loamy Send

3.19, Brown Sandy Clay
End @ 19'
nule; See tied I Report
For USCS Soil Classifications
2460 Auto Park Way
Vlnje 8 Middleton Esoondida. CA 92029-1229
Vnje # 86�f
Engineering, Inc.
(7B0) 743-1214
1

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•2-S BASINS s.,.

Part 1 - Frill Infil[rrtiori Fcassbil�tt Scrcettiug (,t'itexia Wonitl mfdteation of the fall design votantc be feasible from a gthvsical perspective xkithova am undesirable consequences that cannot be.teasonalily mitigated? Ct terra .
_
Yes
No
Is the estimated reliableScLecning.Qucsuon
infiltration rate below proposed
facility locations greater than 0.5 inches per hour? The 1 response to this Screening Question shall be based on a X
comprehensive evaluation of the factors presented in .Appendix C.2 and Appendix D.

Provide basis: TEST DATA WAS COLLECTED FROM SIX S" INCH DIAMETER BORINGS DRILLED TO 4' FEET AND ONE 6" INCH BORING DRILLED TO 19' FEET WITHIN 50' FEET OF THE RESIDENTIAL STORM WATER DETENTION BASIN AREAS. SEE .-ATTACHED INFILTRATION RATE RESULTS AND TEST LOCATIONS. IL-kXINIU11,1 INFILTRATION RATES OF = 0.31 INCHES/FIOUR AND AIINDIUII INFILTRATION RATE = 0.10 1NCFIES/HOUR WERE RECORDED. AVERAGED TESTED INFILTRATION RATES = 0.24 IN/FIR IN BASIN A, 0.103 IN/HR IN BASIN B & 0.26 IN/HR IN BASIN G.

Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of srudv/data source applicability.

Can infiltration greater than 0.5 inches pet hour be allowed without increasing risk of geotechnical hazards (slope
2 stability, groundwater mounding, utilities, of other factors) that cannot be mitigated to an acceptable level? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.2.

Provide basis:

UNKNOW HAZARD POTENTIAL BASED ON COLLECTED FIELD DATA HAVING .AVERAGE INFILTRATION RATES EQUAL TO OR LESS THAN 0.31 INCHES/HOUR.

Surnrrtatize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability.

Template Date: March 29, 2016 Preparation Date:
08/16116
PDP SYI QMP - Attachments

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,. G
SC eeni1�,T-QLestion--,
C.au n1hltIation greater than 0.5 inches per hoar be allowed g
Tres NO
without increasing risk of groundwater contamination
3 (shallow water table, storm water pollutants or other factors) that cannot be mitigated to an acceptable level?'I'he response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.3.

Provide basis:

UNKNOW HAZARD POTENTIAL BASED ON COLLECTED FIELD DATA IL -WING AVERAGE INFILTRATION RATES EQUAL TO OR LESS THAN 0.31 INCHES/HOUR.

Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability.

Can infiltration greater than 0.5 inches per hour be allowed without causing potential water balance issues such as change 4 of seasonally or ephemeral streams or increased discharge of X
contaminated groundwater to surface watets? The response to this Scrccning Question shall be based on a comprehensive evaluation o€the factors prcsontedinA endixC.3.

Provide basin
UNY-NL OW H.1Z ARD POTENTL- IL BASED ON COLLECTED FIELD DATA HAVING AVERAGE INFILTRATION R.,VFES EQUAL TO OR LESS TFL-�N 0.31 INCHES/HOUR.

Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion o€study-/data source applicability.

If all answers to rows 1 - 4 are "Yes" a full infiltration design is potentially feasible.

The feasibility screening category is Full Infiltration PUt.t.

Part 1
INFILTRATION,?
Result*
Nally answer from row I-4 is "No", infiltration may be possible to some extent but NO
would not generally be feasible or desirable to achieve a "full infiltration" design.

Proceed to Part 2
Template Date: March 29, 2016 Preparation Date: %
08/16/16
PDP SVVQMP -Attachments

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Fart Partial Infiltration vs.'No Infiltration Feasibth1%� Screenin�_[:riicrii- Wooki infAiratioit of water in any appreciable amount be physically feasible cviclt4ut anv negative consequences that cannot be reasonably mitigated?
Cate is 5uee iitir Ycs No
Do suit and geologic conditions allow for infiltration in any 5 appreciable rate or volume? The response to tl- s Screening V
A
Question shall be based on a comprehensive evaluation of the factors reseuted in Appendix C.2 and Appendix D.

Provide basis: TEST DATA WAS COI.LF,CTED FROM SIX S" INCH DLUMETER BORINGS DRILLED TO 4' FEET AND ONE G" INCH BORING DRILLED TO 19' FEET WITHIN 50' FEET OF TIME RESIDENTLAL STORM WATER DETENTION BASIN AREAS. SEE ATTACHED INFILTRATION RATE RESULTS ,AND TEST LOCATIONS. 1%1AXIMUM INFILTRATION RATES OF = 0.31 INCHES/HOUR AND i%1INIMUNI INFILTiATION RATE = 0.10 INCHES/HOUR WERE RECORDED, AVERAGED TESTED INTFILTRATION RATES = 0.24 N/HR IN BASIN A, 0.103 IN/HR IN BASIN B & 0.26 IN/HR IN BASIN G.

Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability and why it was not feasible to mitigate low infiltration rates.

Can Infiltration in any appreciable quantity be allowed without increasing risk of geotechnical hazards (slope stability, 6 groundwatet mounding, utilities, or other factors) that cannot X
be mitigated to att acceptable level? The response to dtis Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.2.

Provide basis:

EXISTING OR PROPOSED EARTHEN SLOPES IN EXCESS OF Y FEET WILL NOT BE DOVN1 SLOPE OF THE PROPOSED RESIDENTIAL STORM AUA'1"ER BASINS. ALL OTHER FACTORS ALAY BE l-IITIGATED. INFILTRATION BASINS WILL BE IN CLOSE PROXID-IITY TO THE EXISTING UNDERGROUND UTILITIES. THESE UTILITIES MUST BE PROTECTED FROM DATH AGE POTENTLALLY CAUSED BY THE PROPOSED BASINS.

Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/ data source applicability and why it Nvas not feasible to mitigate loco infiltration rates.

Template Date: March 29, 2016 Preparation Date:
08/16/16
PDP SWQMP o Attachments

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11 /15/2022 PH 1 Page 852 of 1307

W AAA
Cx€tana SLTeertl g QUeSt1011•
Can Infiltration in any appreciable quantity be allowed without 7 posing significant risk for groundwater related concerns x
(shallow water table, storm water pollutants or other factors)? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.3.

Provide basis:

STABALIZED GROUNDWATER CONDIDTIONS WERE OBSERVED AT 13.42' FEET BELOW EMSTING GRADF, IN BORING B. PROPOSED BASIN DEPTH IS 4' FEET BELOW MKISTING GRADE.

IT APPEARS THAT A INIINI.IIUM OF 10' SEPARATION TO GROUNDWATER IS NOT FEASIBLE AT BASIN B. ADDITIONALY IT SI-IOULD BE NOTED THAT THIS IS THE DRY SEASON IN SEVERE DROUGHT CONDITIONS.

GROUNDWATER WAS NOT OBSERVED NEAR BASINS A & G, AND WILL MEET A I\-IININfUM 10' SEPARATION FROM BASIN BOTTObI TO STABALIZED GROUNDWATER ELEVATION.

Summarize fudings of studies; provide reference to studies, calculations, maps, data sources, ere. Provide narrative discussion of study/data source applicability and why it was not feasible to mitigate low infiltration rates.

Can infiltration be allowed without violating downstream 8 water rights? The response to this Screening Question shall he X
based on a comprehensive evaluation of the factors presented in Avveridix C.3.

Provide basis:

DOWNSTREAM WATER RIGI-ITS VIOLATIONS ARE EZPFCTED TO REhLMN UNCI-LINGED AND NON EXISTING.

If all answers from row 5-8 are yes then partial infiltration design is potentially feasible.

The feasibility screening category is Partial Infiltration.

Part 2
1 NO
Result*
If any answer from row 5-8 is no, then infiltration of any volume is considered to be infeasible widen the drainage area. The feasibility screening category is No

INFILTRATION
Infiltration.

Template Date: March 29, 2016
08/17/16
PDP SWQMP - Attachments

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Preparation Date. -
11 /15/2022 PH 1 Page 853 of 1307

The Geotechnical Engineer certifies they completed Form 1-5 except Criteria 4 & 9 (see Appendix C.4.3).

OOOOProfessional Geotechnical Engineers Printed Name:

RALPH MALCOLM VINJE
Professional Geotoc nical Enoneei Sgn sme:
��,t2�LGUtr�`
Date, - Hv.8S3
'1 f prF f' H41t�'p4
The Project Design Engineer certifies they completed Criteria 4 & 8 (see Appendix C.4.4).

Professional PrIecl Design Engineers Printed Name:

Professional Project Design Engineers Signed Name:

Date -
Template Date: March 29, 2016 Preparation Date:

OW6116
POP 5WQMP • Attachments

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11 /15/2022 PH 1 Page 854 of 1307

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ATTACHMENT 1E— POLLUTANT CONTROL BMP DESIGN WORKSHEETS

AND CALCULATIONS

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11 /15/2022 PH 1 Page 857 of 1307

Automated Work -sheet B.1: Calculation of Design Capture Volume (V2.0) 1 Drainagr Basiri Ill or Narnc
1 2
unilless
2 Kith Percentile 24• hr Storm Oepth

0.66 0.66
inches
3 Impervious Surfaces Nat Dirertrd to Dispersion Arra ((:-0.90) 119,767
79,102
sq-ft
4 5
Semi -Pervious Surfaces Not Serving as Dispension Area (C-0.30) E:igiineered Pervious Surfaces Not Serving as Dispersion Area (C=0.10) $5,241
57,922
sq-ft
sq-ft
6 7
Natural Type A Soil Not Serving as Dispersion Area (C=0.10) Natural Type B Soil Not Serving as DisPcxsion Ar (C=0.14) sq-ft
sq-ft
8 Natural Type C Soil Not Scrvingas DisPcxsion Urea (C=0.23) sq ft
9 Nalni-Al T'yl3e D Soil Not Sr. rvingrss I)isltrrson Arra (C=0.30) sq ft
10 1]nes Ttihutary Incorporate Dispersion, Tree Wells, and/or Rain Barrels.

No
No
o
o
o
o
o
\O
No
yes/no
11 1mpe.mo a Surfaces Directed to Dispersion Area per S I ) - B ((a�0.90) sq-ft
12 Semi -Pervious Surfaces Serving as Dispersion Area pet SD-13 (00.30) sq-ft
13 Eno}neeted Pervious Surfaces Sewing as Dispersion Area per SD-B (Ci=0.10) sq-ft
14 Natural Type A Soil Serving as Diapersion Area per SD-B (Ci=0.10) sq-ft
15 Natural Type B Soil Serving as Dispersion Area per SD-B (Ci=0.14) sq-fl
16 Natural Type C Soil Serving as Dispersiom Area 130r SD F3 (Ci =023) sq ft
17 NAlural T'ypr D Soil Serving as Disp ersirm Area pry S I ) B (C-1-0.30) scl tl
18 Number of Tree Wells Proposed per SO,A
i
19 Average Ivlaturc Tree Canopy Diameter
ft
20 Number of Rain Barrels Proposed pet SD-E
#
21 Average Rain Bartel Size
plal
22 Total Tributary Area
205,008
137,024
0 0
0 0
0 0
0 0
sq-ft
23 Ird tial Runoff Factor for Staridard Drainage Arras

0.65 0.65

0.00 0.00

0.00 0.()f)

0.00 0.00
1 0.00

0.00 unillcss
24 25
Triilial Rurioff Factor fox Dispetsed &,. Dislxrsion Arras Initial Wrightml litunoff Fac:ln

0.00 0.65
0,00

0.65 0.00

0.00 0.00
0-00

0.00 0.00

0.011

0.00 0.00
I1.00

0.00 0.00

0.00 0.00
urnitlegs
unttless
26 Initial Design (.:apture Volume
7,329
4,899
0 0
❑
0 0
0 0
0 cubic, feet
27 Total Impervious Area Dispersed to Pervious Surface
0 0
0 0
0 0
0 0
0 0
sq-ft
28 Total Pervious Dispersion Area
0 0
0 0
0 0
0 0
0 0
sq-ft
29 Ratio of Dispersed hnpetvious Area to Pervious Dispersion Are n/a
n/a
n/a
n/a
n/a
n/a
n/a
n/a
n/a
n/a
ratio
30 Adjustment Factor for Dispersed & Dispersion Areas

1.00 1.00

1.00 1.00
ratio
31 Rurtoff Factor Aflcr Dispersion Techniques

0.65 0.65
n/a
n/a
11/a
n/a
n/a
11/a
n/a
n/a
unitless
32 Design Captuxe Volume .After Dislersion Techniyut�
7,329
4,899
0 0
0 0
0 0
0 0
cubic -feet
33 Total Tree Well Vvhu e. Reduc horn
0 0
0 0
t]
0 0
0 !i
0 cubic -feet
34 Total Rain Barrel Volume Reduction
{1
❑
0 0
0 f]
0 0
nthir.-feet
35 Final Adjusted Runoff factor

0.65 0.65

0.00 0-00

0.00 0.00

0.00 000
junitless
36 Final Effective Tributary Area
133,255
89,066
0 ❑
0 U
0 0
0 0
sq-ft
37 Initial Design Capture Volume Retained by Site Design Elements ❑
1 0
0 ❑
0 U
1 0
0 1 ❑
1 0
cubiaiiect
38 Final Design Capture Volume Tributary to BMP
7,329
4,899
0 0
0 0
0 0
o
0 cubk-feet
No Warning Messages

Page 45 of 73 ends

11 /15/2022 PH 1 Page 858 of 1307

Automated Worksheet B.2: Retention Requirements (V2.0)
1 Draina?e Basin ID or Name
1 2uilitless
2 $$th Percentile Rainfall T]ep
0-06

9.(,6
inches
3 Predominant NRCS Soil Type Within BMP Location
D
D
unitless
4 is proposed BMP location Restricted or Unrestricted for lnWtrat on Activities Restricted
Restricted
unitless
5 Mature of Restriction
Groundwater
Groundwater
tlnitless
G
Do Minimum Retention Requirements Apply to this Project Yes
Yes
1-es
Yes
yes/no
•
Are. I IalN t3able Strumires Cs rea te.r Proposed? an 9 Ston es n]posed? No
yes/no
a
rz9y C.cotls:l-lniml Fnglnccr FerfonTi an Tn6ltrAtion Analysis �No
14Y
1 v-s
yes/no
9 DesIgn Infiltrxl.ion Rate l;MX)TTirricndr.d by Gcol.cclini(-Al Hnvneci No
No
in/hr
10 Design InfiltMEOIl Rate Used To Determine RLIcntion Requirements

0.000

0.000
in/hi
11 Percent of Average Annual Runoff that Must be Retained within DMA

1.5%

1.5%
percentage
12 Fraction of DCV Requiaing Retention

0.01 0.01
ratio
13 Required Retention Volume,73
49 cubic -feet
Nan WAnung MeugLp s

Page 46 of 73 ends

11 /15/2022 PH 1 Page 859 of 1307

Automated Worksheet 13,3: f3MP Performance (V2.0)
I
DriunaAe y fls1 M or NAme
1 2
-
-
-
S -ft
2 Dc..i i T.iFh Atinn Rare Rceotnmrndcd

0.000

0.000
-
-
-
in lhr
3 DE-siSp Capture Volume Ttibntiry to BMIP
7,191
5,010
-
-
rnhie-feet
4 Is BMP Vegetated or Unvc ctatcd?
Vc dared
Vc ctatcd
unitless
5 Is BMP hnpunricably Lined or Unliri :d?
Lined
Tined
imiitless
G
Dues I3MP Have: au Underdrain?
Undcrdram
Underdraui
unitless
7 Does BMP Utilize Standard or $ ecialized Media?
Standard
Standard
unitless
8 Provided Surface Area
6,132
8,300
a -ft
9 Provided Surface 1'on - L' cp LI,
6 6
arches
10 Provided Soil Media Thickness
18 18
itches
11 Provided Gravel Thickness(Total Thickness
7 7
inches
12 UndereIrain Clffset
3 3
inches
13 Diameter of Undenifain or T Tydtomod Orifice. Select Smallest 3-00

3.00 inches
14 S ecializcd Soil Media Filtration Rate•
in/fir
15 5 erialized Soil Media Pore Space for Retentirni
imiitless
16 S eriali-zed Svil Media Pure S ace for Bivfiltration unitlesa
17 $ ecialized Gravel Media Porc Sparc
ilniticAS
18 Volume; Infiltrated Over 6 Houx Stonn
0 0
0 t1
0 0
0 0
0 0
cubic• feet
19 PonduW, Pore 5 pace Available for Retention

0.00 0.00

1.00 1.00
1 1.00

1.00 1.00

1.00 unitless
20 Soil Media fore $ ace Available for Retention

0.05 0.05

0.05 0-05

0.05 0.05
0-05

0.05 unitless
21 Gravel Yore Space Available for Retention Above Underdraln

0.00 0.00

0.40 0.40

0.40 0.40
unitless
22 CInvel Pore Space I�vailahle for Retention Blow IJntie rAnni

0.40 0-40

0.40 0.40

0.40 0-40
CI-40
0AD
0-40
0-40
unitless
23 P.ffe.e,6ve Reu rrfivn D . th

2.10 2.10

0.00 0.00
0,00

0.00 0.00

0.00 inches
2-1
fraction of DCV Retained qI nde.pNicte.nt of I7r cln vn'fimel 0-15

0.29 0-00
0-00
0-00
0-00
0-00
000
0-00

0.00 ratio
25 Calmilated Retention Store r. Drawdown Time
120
120
0 0
n
n
0 i5
0 0
hours
26 E fficacy of Re ten lion Processes
0-17

0.30 0-00
RXI
n-nn
0-06
0-00
O ftfi
n-nn

0.00 ratio
?"
Volumc Retained hv B-NTP (Con aidenng T7rawdown Timr,)
1,229
1-493
0 it
n
n
0 0
0 0
rnhie-feet
28 De8iiyp Capture Volumc Renuining forBioliltration
5,962
i7
0 it
0 0
0 0
0 0
cubic fcxI
29 Max H dmmod Flow Ratr Chro Undcalmn

0.3512

0.3D ]?

0.0000

0.1ii1015
0-0000

0.0000
0-0000

0.0000

0.0000
cfs
30 Man Sent Filtration Rat. Allawcd by Undcrdrain O ificc 2-47

1.83 0-00

0.00 0-00
0-00
0-00

0.00 0-00

0.00 in/hr
31 Soil Media Filtration Rate per Specifications

5.00 5A0

5.00 5.00

5.00 5.00
in/hr
32 Soil Media FiWation Rate to he used forSizin.
2-47
1-83
0-00
0-00
0-00
0-00
0-00

0.00 1 0-00

0.00 in/hr
33 Depth Bioftltered Over 6 Hour Storm

14.85 10.97

0.00 0.00

0.00 0.00
itches
34 PondmA Pore Space Available fm Biofiltratirni
1-00

1.00 0.00

0.00 0.00

0.00 imiitless
35 Soil McdiaPorr. Space. Availahlt forBiofiltra.tion

0.20 0.20

0.20 020

0.20 0.20
020
020
020
020
unitless
36 Gravel Pore Space. Available for Riofiltration Above Undeidrain 0-40

0.40 0-40
6-40

0.40 0.40
0-40

0.40 0-40

0.40 imiitless
37 Effective Depth of Biofiltmtion StoraAc
1120
1120

0.00 0-00

0.00 0.00
0-00

0.00 0-00

0.00 inclics
38 Dtawdown Tiine for Surface: Puadin
2 3
0 0
0 0
0 0
0 0
hours
39 Dzawdown Tune; for Efrcc live Biolillration Depth
5 6
0 0
0 0
0 0
1 0
0 hours
40 Total Depth Bwfiltcred

26.05 22-17
0-00

0.00 0.00

0.00 0-00

0.00 inches
41 Option 1- Biofilter 1.50 DCV: TLtAet Volume
8,943
5,276
0 0
0 0
0 0
0 0
cubic -feet
42 Option 1- Provided Biofiltration Volume
8,943
5,276
0 0
0 0
0 0
0 0
cubic -feet
13 Option 2- Store 0.75 DCV: T t Volume
4,471
1 2,636
0 0
0 0
0 0
0 0
cubic -feet
44 0lion 2- Provided Store a Vohune.
4,471
2,63E
0 0
0 0
0 0
0 0
cubic -feet
15 Portion of Binfiltra.tion Performance Standard SA.tiS Sed

1.00 1.00
0-00

0.0i]

0.00 0.00
0-00

0.00 n-nn

0.0n
ratio
16 f--�
Do Site Desi a TUmne itF and WN ' atisfy Anlnla.l Retention R . im remen tn? Yes;
A e$
-
-
e.5/n
17 0vexall Portion of Perfonnarim Stand and $a tisficd MP Effirac Factor 1-00

1.00 0.00
0-00
0-00

0.i1f1
0-00

0.0f1
1 0-00

0.00 1 in do
1R
Deficit of I -.ffe otively Treated Storm water
U
0 n/a
n/a
rt/a
n/a
n/a
n/a
n1a
n/a
jrnbk4eet
No Warning Messages

Page 47 of 73 ends

11 /15/2022 PH 1 Page 860 of 1307

Page 48 of 73 ends

11 /15/2022 PH 1 Page 861 of 1307

ATTACHMENT 2 — HYDROMODIFICATION MANAGEMENT CONTROLS:

SUPPORT DOCUMENTATION & CHECKLIST
❑ Check this box if this attachment is empty because the project is exempt from PDP hydromodification management requirements.

Each of the attachments indicated below should be considered for inclusion with the SWAMP. Use this checklist to indicate which attachments are included behind this coversheet.

Attachment
Contents
Checklist
Sequence
Attachment 2A
Hydromodification
0 Included
Management Exhibit
See Hydromodification Management Exhibit
Checklist on the back of this Attachment cover
sheet.

Attachment 2B
Management of Critical Coarse
Z Exhibit showing project drainage boundaries
Sediment Yield Areas
marked on WMAA Critical Coarse Sediment Yield
See Section 6.2 of the BMP
Area Map
Design Manual.

Analyses, as applicable, for Critical Coarse Sediment
Yield Area Determination, per BMP Design Manual:
❑ 6.2.1 Verification of Geomorphic Landscape
Units Onsite
❑ 6.2.2 Downstream Systems Sensitivity to Coarse
Sediment
❑ 6.2.3 Optional Additional Analysis of Potential
Critical Coarse Sediment Yield Areas Onsite
Attachment 2C
Geomorphic Assessment of
❑ Not performed
Receiving Channels
0 Included
See Section 6.3.4 of the BMP
❑ Submitted as separate stand-alone document
Design Manual.

Attachment 2D
Flow Control Facility Design,
0 Included
including Structural BMP
❑Submitted as separate stand-alone document
Drawdown Calculations and
Overflow Design Summary
See Chapter 6 and Appendix G
of the BMP Design Manual
Attachment 2E
Vector Control Plan
❑ Included
Not required because BMPs will drain in less
than 96 hours

Page 49 of 73 ends

11 /15/2022 PH 1 Page 862 of 1307

ATTACHMENT 2A — HYDROMODIFICATION MANAGEMENT EXHIBIT
For Attachment 2A, provide map(s) for the project site, titled "Hydromodification Management Exhibit." The checklist below identifies minimum elements that must be included with the exhibit. 0 Underlying hydrologic soil group
0 Approximate depth to groundwater
❑%� Existing natural hydrologic features (watercourses, seeps, springs, wetlands, etc.) 0 Critical coarse sediment yield areas to be protected
0 Existing topography and impervious areas
0 Existing and proposed site drainage network and storm drain structures 0 Proposed connections to offsite drainage
0 Proposed demolition
0 Proposed grading
0 Proposed impervious features
0 Proposed design features and surface treatments used to minimize imperviousness 0 Points of Compliance for hydromodification management 0 Existing and proposed drainage boundary and drainage area to each Point of Compliance (when necessary, create separate exhibits for pre -development and post -project conditions) 0 Structural BMPs for hydromodification management (location, type, and size)

Page 50 of 73 ends

11 /15/2022 PH 1 Page 863 of 1307

HYDROMODIFICATION CALCULATIONS
ENVIRONMENTAL PROTECTION AGENCY (EPA) STORM WATER MANAGEMENT MODEL 5.1 (SWMM) CONTINUOUS SIMULATION

MODELS WERE PREPARED FOR THE PRE AND POST -DEVELOPED CONDITIONS AT THE SITE IN ORDER TO DETERMINE IF THE PROPOSED

DETENTION FACILITY HAS SUFFICIENT VOLUME TO MEET CURRENT HYDROMODIFICATION MANAGEMENT PLAN (HMP) REQUIREMENTS

FROM THE SAN DIEGO REGIONAL WATER QUALITY CONTROL BOARD (SDRWQCB), AS ESTABLISHED AT THE HMP DOCUMENT DATED MARCH 2O11, PREPARED BY BROWN AND CALDWELL. THE CONTINUOUS SIMULATION MODEL USES 58 YEARS OF RAINFALL DATA RECORDED BY THE OCEANSIDE RAIN GAUGE (RAINFALL DATA EXISTS FROM 8/28/1951 THROUGH 5/23/2008.

LOW FLOW THRESHOLD
A LOW FLOW THRESHOLD FOR 0.5Q2 VALUE WAS USED TO DETERMINE THE DIAMETER OF THE LOW FLOW ORIFICE.

SWMM DEVELOPMENT
STORMWATER RUNOFF FROM THE PROPOSED PROJECT SITE IS ROUTED TO TWO (2) POINTS OF COMPLIANCE. POC-1 IS LOCATED NEAR THE SOUTHWEST CORNER OF THE PROJECT SITE. POC-1 COLLECTS RUNOFF FROM ONE ONE BASIN. POC-2 LOCATED NEAR THE SOUTHEAST CORNER OF THE PROJECT SITE. POC-2 COLLECTS RUNOFF FROM ONE ONSITE BASIN AND ONE OFFSITE BASIN. THE INPUT DATA REQUIRED TO DEVELOP SWMM ANALYSES INCLUDE RAINFALL, WATERSHED CHARACTERISTICS, AND BMP CONFIGURATIONS.

THE OCEANSIDE GAUGE FROM THE PROJECT CLEAN WATER WEBSITE WAS USE FOR THIS STUDY, SINCE IT IS THE MOST REPRESENTATIVE OF THE SITE PRECIPITATION DUE TO ELEVATION AND PROXIMITY TO THE PROJECT SITE. EVAPORATION FOR THE SITE WAS MODELED USING AVERAGE MONTHLY VALUES FROM THE COUNTY HOURLY DATASET. THE SITE WAS MODELED WITH TYPE D HYDROLOGIC SOILS, SOILS ARE MOSTLY ASSUMED TO BE UNCOMPACTED IN EXISTING CONDITIONS. IN DEVELOPED CONDITIONS, SOILS WITHIN THE

DEVELOPED PORTION OF THE SITE ARE ASSUMED TO BE COMPACTED, WHILE SOILS IN UNDEVELOPED AREAS ARE ASSUMED TO REMAIN UNCOMPACTED. BASED ON THE HMP REVIEW AND AND ANALYSIS PREPARED FOR THE CITY OF VISTA, OTHER SWMM INPUTS FOR THE

SUBAREAS ARE DISCUSSED IN THE APPENDICES OF THE SWMM STUDY, WHERE THE SELECTION OF PARAMETERS IS EXPLAINED IN DETAIL.

HMP MODELING

PRE -DEVELOPED AND POST -DEVELOPED CONDITIONS
THE PRE -DEVELOPED SITE WAS MODELED AS ENTIRELY PERVIOUS, AS REQUIRED BY RWQCB ORDER NO. R9-2013-0001. STORM WATER

RUNOFF FROM THE IMPERVIOUS ROOF AND ROAD AREAS WILL INTERCEPTED BY CATCH BASINS IN THE STREET, AND CONVEYED VIA A STORM DRAIN SYSTEM TO BIOFILTRATION BASINS. TWO (2) BIOFILTRATION BASINS WITH NO INFILTRATION ARE LOCATED WITHIN THE PROJECT SITE AND ARE RESPONSIBLE FOR HANDLING WATER QUALITY REQUIREMENTS FOR POC-1 AND POC-2.

BIOFILTRATION BASINS 1 AND 2 (BMPS 1 AND 2) ARE 6 INCHES DEEP WITH AN INTERNAL OUTLET STRUCTURE (SEE DIMENSIONS IN TABLE 2). FLOWS WILL THEN DISCHARGE FROM THE BASIN VIA THE OUTLET STRUCTURE OR INFILTRATE THROUGH THE BASE OF THE FACILITIES TO THE RECEIVING AMENDED SOIL AND LOW FLOW ORIFICE. THE RISER STRUCTURE WILL ACT AS A SPILLWAY SUCH THAT PEAK FLOWS CAN BE SAFELY DISCHARGED TO THE RECEIVING STORM DRAIN SYSTEM. BENEATH THE BASIN'S INVERT LIES THE PROPOSED LID BIOFILTRATION PORTION OF THE DRAINAGE FACILITIES. THIS PORTION OF THE BASIN IS COMPRISED OF A 3-INCH LAYER OF MULCH, AN 18-INCH LAYER OF AMENDED SOIL (A HIGHLY SANDY, ORGANIC RICH COMPOSITE WITH AN INFILTRATION CAPACITY OF AT LEAST 5 INCHES/HR) AND A 7-INCH RESERVOIR LAYER OF GRAVEL. AN UNDERDRAIN PIPE WITH LOW FLOW ORIFICE OUTLET WILL BE PROVIDED WITHIN THE GRAVEL LAYER TO CARRY AWAY FILTERED RUNOFF TO THE RECEIVING STORM DRAIN SYSTEM. THE BASINS WILL ALSO INCLUDE A 3-INCH SATURATED STORAGE LAYER OF GRAVEL BELOW THE UNDERDRAIN PIPE. A RISER STRUCTURE WILL BE

CONSTRUCTED WITHIN THE BMPS WITH A LOW FLOW ORIFICE OUTLET AND AN EMERGENCY OVERFLOW, SUCH THAT PEAK FLOWS CAN BE SAFELY DISCHARGED TO THE RECEIVING STORM DRAIN SYSTEM (SEE DIMENSIONS IN TABLE 2 AND 3).

THE BIOFILTRATION BASIN WILL ALSO FULFILL WATER QUALITY REQUIREMENTS. THEREFORE, THE BASIN WILL BE DUAL PURPOSE TO

ACHIEVE THE FLOW -DURATION REQUIREMENTS SET FORTH IN THE COUNTY HMP, AS WELL AS ADDRESS THE STORM WATER QUALITY REQUIREMENTS SET FORTH IN THE MS4 PERMIT AS REGIONAL POST -CONSTRUCTION TREATMENT BMPS FOR THE DEVELOPED AREA.

FULL BIOFILTRATION OF THE DCV IS ACHIEVABLE BASED ON THE BASIN FOOTPRINT AND STORAGE PROVIDED ABOVE THE UNDERDRAIN - NAMELY THE SURFACE PONDING, MEDIA AND AGGREGATE STORAGE.

HYDROMODIFICATION & TREATMENT CONTROL BMPS

DEVELOPED CONDITIONS
STORMWATER RUNOFF FROM THE PROPOSED PROJECT SITE IS ROUTED TO TWO (2) POINTS OF COMPLIANCE, POC-1 LOCATED NEAR THE SOUTHWEST CORNER OF THE PROJECT SITE. POC-2 LOCATED NEAR THE SOUTHEAST CORNER OF THE PROJECT SITE. POC-2 COLLECTS RUNOFF FROM ONE ONSITE BASIN AND ONE OFFSITE BASIN.

PRIOR TO DISCHARGING FROM THE PROJECT SITE, DEVELOPED ON -SITE RUNOFF FROM DMA-1 AND DMA 2 IS DRAINED TO ONSITE RECEIVING BIOFILTRATION BASIN FACILITIES FOR POLLUTANT CONTROL, HYDROMODIFICATION AND FLOW DETENTION.

TABLE 1 - SUMMARY OF DMAS:

POC
DMA

TRIBUTARY

AREA (AC)

IMPERVIOUS
PERCENTAGE (%)
1 DMA 1

4.706

58.42%
BMP1

0.141

0.00%
2 DMA 2

3.146

57.73%
BMP 2

0.213

0.00%
BYPASS 2

1.696

0.00%

OFFSITE
SM 1

0.201

0.00%
S M 2

0.009

0.00%
S M 3

0.020

0.00%
S M 4

0.155

0.00%
DISP-1

0.155

60.05%
DMIN-1

0.124
100.00%

BMP MODELING FOR WATER QUALITY PURPOSES

MODELING OF BIOFILTRATION BASINS
TWO (2) BIOFILTRATION BASIN FACILITIES ARE PROPOSED FOR POLLUTANT CONTROL, HYDROMODIFICATION AND FLOW DETENTION. TABLE 2 ILLUSTRATES THE DIMENSIONS REQUIRED FOR HMP COMPLIANCE FOR THE BIOFILTRTION BASINS, BMP 1 AND BMP 2. TABLES 3 ILLUSTRATES THE ORIFICE DIMENSIONS REQUIRED FOR BIOFILTRATION BASIN.

TABLE 2 - SUMMARY OF DIMENSIONS FOR BIOFILTRATION BASINS BMPS:

Dimensions
Biofiltration
Tributary
BMP
Underdrain
Total
Riser
Min.

BMP
Area (Ac)
Area 1�1
Orifice, Djzr
Gravel
Invert
Total
ftZ
(in)
Depth")
EIev,
Surface
BMP 1

4.706
6,147

4.00 7
18 12
BMP 2

3.121
9,279

3.00 7
1 18
12 Notes: (1): Area of amended soi I = area of gravel = area of BMP. (2): Diameter of the orifice in gravel layer with invert at bottom of layer; tied with hydromod min threshold (50%Q2).
(3): Total depth of gravel including 3" of saturated storage located below (4): Depth from bottom of pond to invert of emergency overflow weir.

TABLE 3 - SUMMARY OF ORIFICE DIMENSION FOR BMPS:

Lower Slot Dimensions
Upper Slot Dimensions
Emergency Weir
Biofiltration
Invert
Invert
(#) -
Riser
Weir
Outlet
(#) - Width x
Outlet
BMP
Type`l�
Elev HL��
Height (in) i'i
Type (1)
Elev HL(2}
Width x
Invert
Perimeter
in
in
Height (in)
Elev,
Len th is)
BMP1
Slot
6 (2)-34x5
Slot
7 (1)-10x4
18 11.83
BMP 2
Slot
6 (2)-32x3l
Slot
1 7
(1) - 6 x 2
18 11.83
Notes: (1): Shape of orifice opening in riser structure. (2): Depth from bottom of pond to invert of lower slot or weir. (3): Number of slots and slot dimensions: For examplefor BMP 1: Two 29-inch wide by 3-inch high slots at 6-inches above bottom of basin and one 10-inch wide by 3-inch high slot at 7-inches above bottom of basin.
(4): Depth from bottom of pont to i nvert of emergency overflow weir. (5): Overflow length, the internal perimeter of the riser.

FLOW DURATION CURVE COMPARISION
TYPE G-2 CATCH BASIN
PER D-8

OUTFLOW
THREE (3) 12" RCP III

OUTLET PIPES
30 ML I'

IMPERMEABLE
LINER* EXIST. GROUND

FLOW DURATION CURVES (FDC) WERE COMPARED AT THE PROJECT'S POCS BY EXPORTING THE HOURLY RUNOFF TIME SERIES RESULTS FROM SWMM TO A SPREADSHEET. THE FLOW DURATION CURVES (FDC) FOR POC-1 AND POC-2 WERE COMPARED BETWEEN 10% OF -_ THE EXISTING CONDITION Q2 UP TO THE EXISTING CONDITION Q10. THE Q2 AND Q10 WERE DETERMINED WITH A PARTIAL DURATION STATISTICAL ANALYSIS OF THE RUNOFF TIME SERIES IN AN EXCEL SPREADSHEET USING THE WEIBULL PLOTTING POSITION METHOD.

THE RANGE FROM 10% OF Q2 UP TO Q10 WAS DIVIDED INTO 100 EQUAL TIME INTERVALS; THE NUMBER OF HOURS THAT EACH FLOW RATE WAS EXCEEDED WAS COUNTED FROM THE HOURLY SERIES. ADDITIONALLY, THE INTERMEDIATE PEAKS WITH A RETURN PERIOD "I" WERE OBTAINED (Qi WITH i-3 TO 9). FOR THE PURPOSE OF THE PLOT, THE VALUES ARE PRESENTED AS PERCENTAGE OF TIME EXCEEDED FOR EACH FLOW RATE. FDC COMPARISON FOR POC-1 ARE ILLUSTRATED IN FIGURE 1 AND FIGURE 2 IN BOTH NORMAL AND LOGARITHMIC SCALE IN THE HMP STUDY.

AS CAN BE SEEN IN TABLES 4 AND 5, THE FDC FOR THE PROPOSED CONDITION WITH THE HMP FACILITIES ARE WITHIN 110% OF THE CURVE FOR THE EXISTING CONDITION IN BOTH PEAK FLOW AND DURATION. THE ADDITIONAL RUNOFF VOLUME GENERATED FROM DEVELOPING THE SITE WILL BE RELEASED TO THE STORM DRAIN SYSTEM AT A FLOW RATE BELOW THE 50% Q2 LOWER THRESHOLD.

ADDITIONALLY, THE PROJECT WILL NOT INCREASE PEAK FLOW RATES BETWEEN THE Q2 AND THE Q10, AS SHOWN IN THE FDC PLOTS AND ALSO IN THE PEAK FLOW TABLES.

TABLE 4 - Q2 TO Q10 COMPARISON TABLE - POC-1
Return Period
(years)
Pre-Dev. Peal<
Flows (cfs)
Post-Dev.

Pea(cf Flows
Reduction
(cfs)
LF = 0.1xQ2

1.318

0.987

0.331
2-year

2.635

1.973

0.662
3-year

2.847

2.317

0.530
4-year

3.262

2.696

0.566
5-year

3.346

2.914

0.432
6-year

3.446

3.051

0.393
7-year

3.648

3.132

0.517
8-year

3.737

3.160

0.577
9-year

3.985

3.169

0.817
10-year

4.249

3.216

1.033
TABLE 5 - Q2 TO Q10 COMPARISON TABLE - POC-2
Return Period
(years)
Pre-Dev. Peal<
Flows (cfs)
Post-Dev.

Peal< Flows
(cfs)
Reduction
(cfs)
LF = 0.1xQ2

1.112

0.474

0.638
2-year

2.224

0.948

1.276
3-year

2.398

1.032

1.366
4-year

2.744

1.166

1.578
5-year

2.825

1.208

1.617
6-year

2.896

1.247

1.648
7-year

3.063

1.315

1.748
8-year

3.138

1.349

1.789
9-year

3.369

1.427

1.942
10-year

3.603

1.513

2.090
TYPE G-1 CATCH BASIN
PER D-8

DEEP ROUTED, DENSE,

DROUGHT TOLERANT

PLANTING SUITABLE FOR

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3" MULCH
18" AMENDED SOIL MIN. INFILTRATION RATE 5"/HR

RESTRICTER CAP TO LIMIT FLOW
OUT OF V2 STORAGE AREA, LID
DRAIN DOWN HOLE, d = 4.00"
ME-
LEGEND
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- -
-
O2 BASIN HEIGHT HMAX = 30.00"
_
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-
I
-
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4" PEA GRAVEL
_
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7" GRAVEL LAYER
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FOR V2 STORAGE
1 - 5" HIGH X 34" LONG OPENING
70 `UPPER SLOT INVERT = 7.00"
6" PERFORATED PVC PIPE
1 - 4" HIGH X 10" LONG OPENING

CONFORMING TO ASTM D
PC POLLUTANT CONTROL WSEL = 6.00"
3034 OR EQUIVALENT
3" DEAD STORAGE
HC HYDROMODIFICATION CONTROL WSEL = 13.92"

BELOW UNDERDRAIN
BIOFILTRATION BASIN DETAIL, BMP 1

SEE COLORADO LINING INTERNATIONAL PVC 30
HTTP: //WWW.COLORADOLINING.COM/PRODUCTS/PVC.PDF) OR APPROVED EQUAL.

DEEP ROUTED, DENSE,

DROUGHT TOLERANT

PLANTING SUITABLE FOR

WELL DRAINED SOIL
FC FLOOD CONTROL WSEL = 18.00"
*ELEVATION MEASURED FROM BASIN SURFACE
i= LEGEND
0FREEBOARD = 12.00" (CONJUNCTIVE USE FACILITY)
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- I
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OUT OF V2 STORAGE AREA, LID BELOW UNDERDRAIN
DRAIN DOWN HOLE, d = 3.00"
FC FLOOD CONTROL WSEL = 18.00"
BIOFILTRATION BASIN DETAIL, BMP 2 *ELEVATION MEASURED FROM BASIN SURFACE

NOT TO SCALE
0 OUTFLOW
PCI l 1 3" MULC
18" AMENDED SOIL MIN. INFILTRATION RATE 5"/HR
*30 MILLINER NOTE: 30-MIL IMPERMEABLE LINER FOR BIORETENTION CONFORM TO THE FOLLOWING SPECIFICATIONS: SPECIFIC GRAVITY (ASTM D792): 1.2 (G/CC, MIN.); TENSILE (ASTM D882): 73 (LB/IN-WIDTH, MIN); ELONGATION AT BREAK (ASTM D882): 380 (%, MIN); MODULUS (ASTM D882):
30 (LB/IN-WIDTH, MIN.); AND TEAR STRENGTH (ASTM D1004): 8 (LB/IN, MIN); SEAM SHEAR STRENGTH (ASTM D882) 58.4 (LB/IN, MIN); SEAM PEEL STRENGTH (ASTM D882) 15 (LB/IN, IN).

SEE COLORADO LINING INTERNATIONAL PVC 30
HTTP: //WWW.COLORADOLINING.COM/PRODUCTS/PVC.PDF) OR APPROVED EQUAL.

MALE NATIONAL PIPE THREAD

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5115 AVENIDA ENCINAS
SUITE 1"
CARLSBAD, CA. 92008-4387
(760) 931-8700

NOT TO SCALE
K:\Cililf\6)�b� G\SWMP\HMP_TSM.dwg, 12/7/2021 11:48:35 AM PH1 Page 865 of 1307

SUMMARY OF PRE -DEVELOPED

CONDITION DRAINAGE AREAS
0 DISCHARGE LOCATION (PO\ PRE -DEVELOPMENT AREA (AC)
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LEGEND

BASIN BOUNDARY

PROPERTY LINE - - - - -

FLOW LINE - -

SOIL TYPE BOUNDARY -
40' 20' 0' 40' 80' 120'
SCALE: 1 " = 40'
A,nc.

Dana pnhg, �(engineering, surveying
5115 AVENIDA ENCINAS
SUITE "L"
CARLSBAD, CA. 92008-4387
(760) 931-8700
K:\Cill f�\61nn 1 G\SWMP\EX_HMP_TSM.dwg, 8/25/2021 4:30:44 PM PH1

Page 866 of 1307 ends

ATTACHMENT 213— MANAGEMENT OF CRITICAL COARSE SEDIMENT

YIELD AREAS

Page 51 of 73 ends

11 /15/2022 PH 1 Page 867 of 1307

ATTACHMENT 2C— GEOMORPHIC ASSESSMENT

Page 53 of 73 ends

11 /15/2022 PH 1 Page 869 of 1307

HYDROMODIFICATION SCREENING
FOR

CAMINO LARGO
September 14, 2021
Will sign and stamp upon approval
Wayne W. Chang, MS, PE 46548
changwaullhilm
Civil Engineering - Hydrology - Hydraulics - Sedimentation P.O. Box 9496
Rancho Santa Fe, CA 92067
(858) 692-0760
11/15/2022 FOR REV►I ONLY Page 870 of 1307

-TABLE OF CONTENTS -
Introduction................................................................................................................................1 Domainof Analysis...................................................................................................................2 InitialDesktop Analysis.............................................................................................................5 FieldScreening..........................................................................................................................6 Conclusion...............................................................................................................................10 Figures......................................................................................................................................11

APPENDICES
A. SCCWRP Initial Desktop Analysis
B. SCCWRP Field Screening Data

MAP POCKET
Study Area Exhibit
11/15/2022 FOR REV►I ONLY Page 871 of 1307

INTRODUCTION
The city of Vista's June 2016, BMP Design Manual, outlines low flow thresholds for hydromodification analyses. The thresholds are based on a percentage of the pre -project 2-year flow (Q2), i.e., 0.1Q2 (low flow threshold and high susceptibility to erosion), 0.3Q2 (medium flow threshold and medium susceptibility to erosion), or 0.5Q2 (high flow threshold and low susceptibility to erosion). A flow threshold of O.1Q2 represents a natural downstream receiving conveyance system with a high susceptibility to bed and/or bank erosion. This is the default value used for hydromodification analyses and will result in the most conservative (largest) on -site facility sizing. A flow threshold of 0.3Q2 or 0.5Q2 represents downstream receiving conveyance systems with a medium or low susceptibility to erosion, respectively. In order to qualify for a medium or low erosion susceptibility rating, a project must perform a channel screening analysis based on the March 2010, Hydromodification Screening Tools: Field Manual for Assessing Channel Susceptibility, developed by the Southern California Coastal Water Research Project (SCCWRP). The SCCWRP results are compared with the critical shear stress calculator results from the County of San Diego's Critical Flow Calculator spreadsheet to establish the appropriate erosion susceptibility threshold of low, medium, or high.

T
This report provides a hydromodification screening analysis for the Camino Largo single-family residential project being designed by BHA, Inc. The 9.3-acre site currently supports a nursery and is located northeast of the intersection of North Santa Fe Avenue and Camino Largo in the city of Vista (see the Vicinity Map). The nursery will be redeveloped with 46 homes and private streets.

Under pre -project conditions, storm runoff within the project footprint generally sheet flows in a southerly direction towards Camino Largo, which is an unpaved private street. The runoff continues a short distance (100+ feet) south and enters an unnamed natural drainage course that 11 /15/2022 PH 1 Page 872 of 1307

flows in a westerly direction along the south side of Camino Largo (see the Study Area Exhibit in the map pocket). The unnamed natural drainage course crosses North Santa Fe Avenue in an arch culvert then continues northwest over 2.3 miles to a confluence with the San Luis Rey River.

Under post -project conditions, the project runoff will be treated by one of two biofiltration basins.

Runoff from the easterly half of the project will enter a biofiltration basin at the southeast corner of the site. A proposed storm drain will convey the treated runoff out of the biofiltration basin and discharge towards the unnamed natural drainage course. Runoff from the westerly half of the project will enter a biofiltration basin at the southwest corner of the site. A proposed storm drain will convey the treated runoff out of the biofiltration basin and to the North Santa Fe Avenue culvert. The post -project runoff from both halves of the project will ultimately be conveyed away from the site by the unnamed natural drainage course similar to existing conditions.

The SCCWRP screening tool requires both office and field work to establish the vertical and lateral susceptibility of a downstream receiving channel to erosion. The vertical and lateral assessments are performed independently of each other although the lateral results can be affected by the vertical rating. A screening analysis was performed to assess the low flow threshold for the project's two points of compliance (POC), which are the first locations where the project's runoff discharges to natural conveyances. The first POC, labeled POC A, is at the outlet of the proposed storm drain from the southeast biofiltration basin. The second POC, labeled POC B, is at the outlet of the North Santa Fe Avenue culvert.

The initial step in performing the SCCWRP screening analysis is to establish the domain of analysis and the study reaches within the domain. This is followed by office and field components of the screening tool along with the associated analyses and results. The following sections cover these procedures in sequence.

DOMAIN OF ANALYSIS
SCCWRP defines an upstream and downstream domain of analysis, which establish the study limits. The County of San Diego's HMP specifies the downstream domain of analysis based on the SCCWRP criteria. The HMP indicates that the downstream domain is the first point where one of these is reached:
• at least one reach downstream of the first grade control point • tidal backwater/lentic waterbody
• equal order tributary
• accumulation of 50 percent drainage area for stream systems or 100 percent drainage area for urban conveyance systems (storm drains, hardened channels, etc.).

The upstream limit is defined as:
2 11 /15/2022 PH 1 Page 873 of 1307

• proceed upstream for 20 channel top widths or to the first grade control point, whichever comes first. Identify hard points that can check headward migration and evidence of active headcutting.

SCCWRP defines the maximum spatial unit, or reach (a reach is circa 20 channel widths), for assigning a susceptibility rating within the domain of analysis to be 200 meters (656 feet). If the domain of analysis is greater than 200 meters, the study area can be subdivided into smaller reaches of less than 200 meters for analysis. Most of the units in the HMP's SCCWRP analysis are metric.

Metric units are used in this report only where given so in the HMP. Otherwise English units are used.

Downstream Domain o Analysis
The downstream domain of analysis location for each point of compliance (POC) was determined by assessing and comparing the four bullet items above. A POC represents the point below which a channel is natural and subject to hydromodification impacts. As discussed in the Introduction, storm runoff from the project will be treated by one of two biofiltration basins and then conveyed below the project by hardened, non -erodible storm drain pipes to natural conveyances. The two outlets into the natural conveyances are labeled POC A and POC B, respectively. A downstream domain of analysis location was selected below each POC as follows.

Per the first bullet item, the first permanent grade controls below POC A and POC B were identified during a site visit. The storm runoff from POC A flows a short distance to the unnamed natural drainage course and then continues west in the unnamed natural drainage course. The runoff reaches the North Santa Fe Avenue culvert approximately 1,000 feet downstream of POC A. The culvert is a non -erodible facility that provides a grade control for the upstream channel bed. i.e., it will prevent erosion of the upstream channel bed. This is the first permanent grade control below POC A.

The storm runoff from POC B discharges directly into the unnamed natural drainage course from the North Santa Fe Avenue culvert outlet. The runoff continues west in the unnamed natural drainage course a distance of 516 feet before reaching a road crossing with a culvert (see Figure 6). This culvert is the first permanent grade control reached below POC B.

The second bullet item criteria are based on reaching a lentic (standing or still water such as ponds, pools, marshes, lakes, lagoons, etc.) or tidal waterbody. The nearest such waterbody below POC A and POC B is the Upper Pond within Guajome Regional Park. The unnamed natural drainage course flows into the Upper Pond over 1.1 miles downstream of North Santa Fe Avenue. This lentic waterbody is further downstream from POC A and POC B than their first permanent grade controls, so the second bullet item will not govern over the first bullet item in establishing the downstream domain of analysis location for either POC.

The third bullet item is met when the natural watercourse below a POC confluences with a stream with an equal order or larger tributary area. The runoff from POC A flows 90 feet within a natural swale before confluencing with the unnamed natural drainage course. Topographic mapping indicates that the unnamed natural drainage course's watershed area at the confluence is much larger than the natural swale's watershed area. Therefore, the third bullet item criteria for POC A 11 /15/2022 PH 1 Page 874 of 1307

is met where the natural swale below POC A confluences with the unnamed natural drainage course. The confluence is closer to POC A than its downstream permanent grade control, so the third bullet item governs over the first in establishing the downstream domain of analysis location for POC A.

POC B is within the unnamed natural drainage course. Google Earth and a site visit reveal that the unnamed natural drainage course does not confluence with a larger stream between POC B and its first permanent grade control located 516 feet below POC B. Therefore, the third bullet item will not govern over the first in establishing the downstream domain of analysis location for POC B.

The fourth bullet item is met when the natural stream below a POC accumulates 50 or 100 percent drainage area for natural or urban drainage systems, respectively. Both streams below each POC are natural systems, so 50 percent applies. The Study Area Exhibit shows that the stream below POC A accumulates minor area (0.35 acres) between POC A and the confluence with the unnamed natural drainage course. The accumulated area is much less than 50 percent of the area tributary to POC A (3.29 acres). Therefore, fourth bullet item will not govern over the third in establishing the downstream domain of analysis location for POC A.

The Study Area Exhibit indicates that the unnamed natural drainage course below POC B accumulates minor area between POC B and its downstream permanent grade control. The accumulated area is much less than 50 percent of the area tributary to POC B. Therefore, the fourth bullet item will not govern over the first in establishing the downstream domain of analysis location for POC A.

Based on the above information, the downstream domain of analysis location is established by separate criteria for POC A and POC B. For POC A, the location is based on the third bullet item.

The natural swale below POC A confluences with the much larger unnamed natural drainage course 90 feet downstream of POC A. This location is closer to POC A than the locations determined by the other bullet item criteria.

For POC B, the downstream domain of analysis location is based on the first bullet item. A permanent grade control occurs where the unnamed natural drainage course enters a roadway culvert below POC B. This is the first downstream domain of analysis point reached from the four bullet criteria. Per the first bullet item, the downstream domain of analysis location should be set one reach (656 feet) below the grade control. Therefore, the downstream domain of analysis location for POC B is 650 feet below the grade control.

Upstream Domain ofAnalysis
The hardened, non -erodible drainage facilities leading to the POC A outlet into the uppermost end of the receiving natural swale. Since the natural swale does not extend upstream of POC A, the upstream domain of analysis location for POC A is at POC A.

The North Santa Fe Avenue culvert extends upstream of POC B. In addition, the project's topographic mapping shows a rock outcropping in the unnamed natural drainage course immediately upstream of the culvert. These culvert and rocks are hard points that check headward 4 11 /15/2022 PH 1 Page 875 of 1307

migration in the unnamed natural drainage course. Therefore, the upstream domain of analysis location for POC B is at POC B.

Study Reaches within Domain ofAnalysis
After the upstream and downstream domain of analysis locations are established for POC A and POC B, the study reaches associated with each POC are identified (see the Study Area Exhibit in the map pocket). For POC A, the entire domain of analysis extends from the upstream domain of analysis location at POC A to the downstream domain of analysis location at the confluence of the natural swale below POC A with the unnamed natural drainage course. This reach extends over 90 feet and is labeled Reach 1.

For POC B, the entire domain of analysis extends from the upstream domain of analysis location at POC B to the downstream domain of analysis location 656 feet below the permanent grade control created by a roadway culvert. The domain of analysis was analyzed as two study reaches, Reach 2 and Reach 3. Reach 2 extends 516 feet from the upstream domain of analysis location at POC B to the first permanent grade control below POC B. Reach 2 extends from the first permanent grade control to a point 656 feet below the grade control. All three study reaches are within the 656 foot (200 meters) maximum reach length recommended by SCCWRP.

INITIAL DESKTOP ANALYSIS
After the domain of analysis is established, SCCWRP requires an "initial desktop analysis" that involves office work. The initial desktop analysis establishes the watershed area, mean annual precipitation, valley slope, and valley width. These terms are defined in Form 1, which is included in Appendix A. SCCWRP recommends the use of National Elevation Data (NED) to determine the watershed areas, valley slopes, and valley widths. NED data is similar to USGS quadrangle mapping.

The Reach 1 watershed area is based on BHA, Inc's. proposed condition hydrology, which determined that 3.29 acres is tributary to POC A (see Appendix A for their Post -Development Hydrology exhibit). The Study Area Exhibit shows that an additional 0.35 acres is tributary to the natural swale below POC A, so the total Reach 1 watershed area covers 3.64 acres (0.0057 square miles).

The watershed areas associated with Reach 2 and 3 were delineated from the USGS' StreamStats program, which is based on their Digital Elevation Model and a digital representation of the stream network. The StreamStats results are included in Appendix A. The watershed delineations are consistent with current USGS quadrangle mapping. Streamstats shows that the watershed areas tributary to Reach 2 and 3 are 676.46 and 739.62 acres (1.0570 and 1.1557 square miles), respectively.

The mean annual precipitation was obtained from the rain gage closest to the site. This is the Western Regional Climate Center's Vista 2NNE gage (see Appendix A). The average annual rainfall measured at the Vista 2NNE gage for the period of record is 13.09 inches. 5 11 /15/2022 PH 1 Page 876 of 1307

The valley slope and valley width for Reach 1, 2, and 3 were obtained from 1-foot contour interval topographic mapping prepared for the project supplemented with SANGIS' 2014 2-foot contour interval topographic mapping. NED data was not used because it is not very accurate for these parameters. The valley slope is the longitudinal slope of the channel bed along the flow line, so it is determined by dividing the elevation difference within a study reach by the length of the flow line. The valley width is the valley bottom width dictated by breaks in the hillslope. The valley slope and valley width within Reach 1, 2, and 3 along with their watershed areas are included in Table 1.

Reach Tributary Watershed Valley Slope, Valley Width,
Area, sq. mi. m/m In
F 1 7 0.0057 0.0722 2.44

1.0570 0.0099 9.14
3 1.1557 0.0136 9.14
Table 1. Summary of Watershed Area, Valley Slope, and Valley Width The above described values were input to a spreadsheet to calculate the simulated peak flow, screening index, and valley width index outlined in Form 1. The input data and results are tabulated in Appendix A. This completes the initial desktop analysis.

FIELD SCREENING
After the initial desktop analysis is complete, a field assessment must be performed. The field assessment is used to establish a natural channel's vertical and lateral susceptibility to erosion.

SCCWRP states that although they are admittedly linked, vertical and lateral susceptibility are assessed separately for several reasons. First, vertical and lateral responses are primarily controlled by different types of resistance, which, when assessed separately, may improve ease of use and lead to increased repeatability compared to an integrated, cross -dimensional assessment. Second, the mechanistic differences between vertical and lateral responses point to different modeling tools and potentially different management strategies. Having separate screening ratings may better direct users and managers to the most appropriate tools for subsequent analyses.

The field screening tool uses combinations of decision trees and checklists. Decision trees are typically used when a question can be answered fairly definitively and/or quantitatively (e.g., d50 < 16 mm). Checklists are used where answers are relatively qualitative (e.g., the condition of a grade control). Low, medium, high, and very high ratings are applied separately to the vertical and lateral analyses. When the vertical and lateral analyses return divergent values, the most conservative value shall be selected as the flow threshold for the hydromodification analyses.

Vertical Stability
The purpose of the vertical stability decision tree (Figure 6-4 in the County of San Diego HMP) is to assess the state of the channel bed with a particular focus on the risk of incision (i.e., down 6 11/15/2022 PH1 Page 877 of 1307

cutting). The decision tree is included in Figure 10. The first step is to assess the channel bed resistance. There are three categories defined as follows:

1. Labile Bed — sand -dominated bed, little resistant substrate.

2. Transitional/Intermediate Bed — bed typically characterized by gravel/small cobble, Intermediate level of resistance of the substrate and uncertain potential for armoring.

3. Threshold Bed (Coarse/Armored Bed) — armored with large cobbles or larger bed material or highly -resistant bed substrate (i.e., bedrock).

Based on the photographs and site investigation, the bed material and resistance is generally within the transitional/intermediate bed category. There was no evidence of a threshold bed condition.

However, some bed areas contained smaller grain sizes typically found in a labile bed.

In addition to the material size and compaction, there are several factors that establish the erodibility of a channel such as the flow rate (i.e., size of the tributary area), grade controls, channel slope, vegetative cover, channel planform, etc. The Introduction of the SCCWRP Hydromodification Screening Tools: Field Manual identifies several of these factors. When multiple factors influence erodibility, it is appropriate to perform the more detailed SCCWRP analysis, which is to analyze a channel according to SCCWRP's transitional/intermediate bed procedure. This requires the most rigorous steps and will generate the appropriate results given the range of factors that define erodibility. The transitional/intermediate bed procedure takes into account that bed material may fall within the labile category (the bed material size is used in SCCWRP's Form 3 Figure 4), but other factors may trend towards a less erodible condition. Dr.

Eric Stein from SCCWRP, who co-authored the Hydromodification Screening Tools: Field Manual in the Final Hydromodification Management Plan (HMP), indicated that it would be appropriate to analyze channels with multiple factors that impact erodibility using the transitional/intermediate bed procedure. Consequently, this procedure was used to produce more accurate results.

Transitional/intermediate beds cover a wide susceptibility/potential response range and need to be assessed in greater detail to develop a weight of evidence for the appropriate screening rating. The three primary risk factors used to assess vertical susceptibility for channels with transitional/intermediate bed materials are:

1. Armoring potential — three states (Checklist 1)

2. Grade control — three states (Checklist 2)

3. Proximity to regionally -calibrated incision/braiding threshold (Mobility Index Threshold — Probability Diagram)
These three risk factors are assessed using checklists and a diagram (see Appendix B), and the results of each are combined to provide a final vertical susceptibility rating for the intermediate/transitional bed -material group. Each checklist and diagram contains a Category A, 7 11 /15/2022 PH 1 Page 878 of 1307

B, or C rating. Category A is the most resistant to vertical changes while Category C is the most susceptible.

Checklist 1 determines armoring potential of the channel bed. The channel bed along each of the three study reaches is within Category B, which represents intermediate bed material of unknown resistance or unknown armoring potential due to a surface veneer such as vegetation. The soil was probed and penetration was relatively difficult through the underlying layer. The dense, mature vegetative growth along the channel of Reach 1, 2, and 3 serve to armor the channel bed and resist vertical erosion.

Checklist 2 determines grade control characteristics of the channel bed. This is established by the spacing of the grade controls along the channel. Category B on Checklist 2 is based on a spacing of 2/Sv or 4/5,, where Sv is the channel slope. The Sv value of Reach 1, 2, and 3 are included in Form 1 results in Appendix A and summarized in Table 2. Table 2 also summarizes the 2/Sv or 4/Sv of each reach along with the length. Reach 1 and Reach 2 are both shorter than their 2/Sv values, so are in Category A on Checklist 2. On the other hand, Reach 3 is between its 2/Sv and 4/Sv, so is in Category B.

Reach FS,, ft/ft I 2/S,, feet I 4/S,, feet I Length, feet Category

0.0722 1 91 182 1 90

0.0099 1 664 F 1,328 1 516

0.0136
1 484
F 967
1 656
Table 2. Checklist 2 Summary
The Screening Index Threshold is a probability diagram that depicts the risk of incising or braiding based on the potential stream power of the valley relative to the median particle diameter. The threshold is based on regional data from Dr. Howard Chang of Chang Consultants and others. The probability diagram is based on dso as well as the screening index (INDEX) value determined in the initial desktop analysis (see Appendix A). The Form 1 results in Appendix A determined an INDEX of 0.0147 and 0.0196 for Reach 1 and Reach 2, respectively. SCCWRP specifies use of a US SAH-97 half -phi template gravelometer to determine dso in a natural channel. This gravelometer allows a minimum dso measurement of 2 millimeters. The Screening Index Threshold diagram shows that the probability of incising or braiding is less than 50 percent for a dso of 2 millimeters if the INDEX value is 0.022 or less. Since the Reach 1 and Reach 2 Screening Index values are both less than the 50 percent INDEX value, Reach 1 and Reach 2 are both within Category A.

For Reach 3, dso had to be determined to assess the Screening Index Threshold. dso can be derived from a pebble count in which a minimum of 100 particles are obtained along transects at the site.

SCCRWP states that if fines less than 1/2-inch thick are at a sample point, it is appropriate to sample the coarser buried substrate. The dso value is the particle size in which 50 percent of the particles are smaller and 50 percent are larger. The pebble count results for Reach 3 are included in Appendix B. The results show a dso of 8 millimeters. Plotting the dso and screening index value on 8 11/15/2022 PH1 Page 879 of 1307

the Mobility Index Threshold diagram shows Reach 3 has a less than 50 percent probability of incising or braiding, which falls within Category A.

The overall vertical rating is determined from the Checklist 1, Checklist 2, and Mobility Index Threshold results. The scoring is based on the following values:

Category A = 3, Category B = 6, Category C = 9
The vertical rating score is based on these values and the equation:

Vertical Rating = [(armoring X grade control)112 X screening index scoref2 Table 3 summarizes the Checklist 1, 2, and 3 values for each reach as well as their vertical rating.

The results show the vertical rating for all three study reaches is less than 4.5, so these reaches have a low threshold for vertical susceptibility.

Reach Checklist 1 Checklist 2 Checklist 3 Vertical
(armoring) (grade control) (screening index) i Rating
6 3 F-- 3 3.6
2 6 3 3 3.6
3 6 6 3 4.2
Table 3. Overall Vertical Rating
Lateral Stability
The purpose of the lateral decision tree (Figure 6-5 from County of San Diego HMP included in Figure 11) is to assess the state of the channel banks with a focus on the risk of widening. Channels can widen from either bank failure or through fluvial processes such as chute cutoffs, avulsions, and braiding. Widening through fluvial avulsions/active braiding is a relatively straightforward observation. If braiding is not already occurring, the next logical step is to assess the condition of the banks. Banks fail through a variety of mechanisms; however, one of the most important distinctions is whether they fail in mass (as many particles) or by fluvial detachment of individual particles. Although much research is dedicated to the combined effects of weakening, fluvial erosion, and mass failure, SCCWRP found it valuable to segregate bank types based on the inference of the dominant failure mechanism (as the management approach may vary based on the dominant failure mechanism). A decision tree (Form 4 in Appendix B) is used in conducting the lateral susceptibility assessment. Definitions and photographic examples are also provided below for terms used in the lateral susceptibility assessment.

The first step in the decision tree is to determine if lateral adjustments are occurring. The adjustments can take the form of extensive mass wasting (greater than 50 percent of the banks are exhibiting planar, slab, or rotational failures and/or scalloping, undermining, and/or tension cracks). The adjustments can also involve extensive fluvial erosion (significant and frequent bank cuts on over 50 percent of the banks). Neither mass wasting nor extensive fluvial erosion was evident within either of the three reaches during a field investigation. As seen in the figures and 9 11 /15/2022 PH 1 Page 880 of 1307

topographic mapping, the channel banks are mostly gentle and heavily vegetated confirming that mass wasting and extensive fluvial erosion has not occurred.

The next step in the Form 4 decision tree is to assess the consolidation of the bank material. The banks in Reach 1, 2, and 3 were moderate to well -consolidated. This determination was made because the ground surface was difficult to penetrate with a probe. The banks were densely vegetated and/or relatively level and stable as seen in the figures. In addition, the banks showed little evidence of crumbling and were composed of relatively well -packed particles.

Form 6 (see Appendix B) is used to assess the probability of mass wasting. Form 6 identifies a 10, 50, and 90 percent probability based on the bank angle and bank height. From the topographic mapping and site investigation, the average bank angles in all three reaches are 2:1 (26.6 degrees) or flatter. Form 6 shows that the probably of mass wasting and bank failure has less than 10 percent risk for a 26.6 degree bank angle or less regardless of the bank height.

The final two steps in the Form 4 decision tree are based on the braiding risk determined from the vertical rating as well as the Valley Width Index (VWI) calculated in Appendix A. If the vertical rating is high, the braiding risk is considered to be greater than 50 percent. Excessive braiding can lead to lateral bank failure. For Reach 1, 2, and 3 the vertical rating is low, so the braiding risk is less than 50 percent. Furthermore, a VWI greater than 2 represents channels unconfined by bedrock or hillslope and, hence, subject to lateral migration. The VWI calculations in the spreadsheet in Appendix A show that VWI for Reach 1, 2, and 3 are 1.40, 0.72, and 0.70, respectively, which are all less than 2.

From the above steps, the lateral susceptibility rating is low for Reach 1, 2, and 3 (colored circles are included on the Form 4: Lateral Susceptibility Field Sheet decision tree in Appendix B showing the decision path).

CONCLUSION
The SCCWRP channel screening tools were used to assess the downstream channel susceptibility for the Camino Largo single-family residential project being designed by BHA, Inc. Storm runoff from the project will be collected by proposed on -site drainage systems, treated by one of two on - site BMPs, and conveyed off -site by storm drain pipes. A channel assessment was performed for the natural streams below each POC based on office analyses and field work. The results indicate a low threshold for vertical and lateral susceptibilities for Reach 1, 2, and 3.

The HMP requires that these results be compared with the critical stress calculator results outlined in the County of San Diego HMP. The critical stress results are included in Appendix B for the study reach using the spreadsheet provided by the County. The channel dimensions were estimated from topographic mapping and Google Earth. Based on these values, the critical stress results returned a low threshold consistent with the SCCWRP channel screening results. Therefore, the SCCWRP analyses and critical stress calculator demonstrate that a low overall threshold is applicable to the project (i.e., 0.5Q2).
10 11 /15/2022 PH 1 Page 881 of 1307

Figure 1. Looking Downstream towards Reach 1 from Upper End near Future POC A Figure 2. North Santa Fe Avenue Culvert Outlet at POC B 11 11 /15/2022 PH 1 Page 882 of 1307

Figure 3. Looking Downstream towards Reach 2 from Upper End at POC B Figure 4. Dense Vegetation within Middle of Reach 2
12 11 /15/2022 PH 1 Page 883 of 1307

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Figure 10. SCCWRP Vertical Channel Susceptibility Matrix 16 11 /15/2022 PH 1 Page 887 of 1307

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Figure 11. SCCWRP Lateral Channel Susceptibility Matrix 17 11 /15/2022 PH 1 Page 888 of 1307

APPENDIX A

SCCWRP INITIAL DESKTOP ANALYSIS
11 /15/2022 PH 1 Page 889 of 1307

FORM 1: INITIAL DESKTOP ANALYSIS
Complete all shaded sections.

IF required at multiple locations, circle one of the following site types:

Applicant Site / Upstream Extent / Downstream Extent
Location: Latitude:

Description (river name, crossing streets, etc.):

Longitude:

GIS Parameters: The International System of Units (SI) is used throughout the assessment as the field standard and for consistency with the broader scientific community. However, as the singular exception, US Customary units are used for contributing drainage area (A) and mean annual precipitation (P) to apply regional flow equations after the USGS. See SCCWRP Technical Report 607 for example measurements and "Screening Tool Data Entry.xls" for automated calculations.

Form 1 Table 1. Initial desktop analysis in GIS.

Symbol Variable Description and Source Value
A Area Contributing drainage area to screening location via published (mi) Hydrologic Unit Codes (HUCs) and/or <_ 30 m National Elevation Data F (NED), USGS seamless server
m a.
o P Mean annual Area -weighted annual precipitation via USGS delineated polygons using w CL precipitation records from 1900 to 1960 (which was more significant in hydrologic (in) models than polygons delineated from shorter record lengths) S Valley slope Valley slope at site via NED, measured over a relatively homogenous (m/m) valley segment as dictated by hillslope configuration, tributary a confluences, etc., over a distance of up to —500 m or 10% of the main - channel length from site to drainage divide
o
a _ W Valley width Valley bottom width at site between natural valley walls as dictated by a? (m) clear breaks in hillslope on NED raster, irrespective of potential i) armoring from floodplain encroachment, levees, etc. (imprecise measurements have negligible effect on rating in wide valleys where VWI is» 2, as defined in lateral decision tree)
Form 1 Tabl a 2. Simplif ied peak flo w, screening index, and valley width index. Values for this table should be calculated in the sequence shown in this table, using values from Form 1 Table 1.

Symbol Dependent Variable Equation Required Units Value Q10cfs 10-yr peak flow (ft3/s) Qlocfs = 18.2 * A 0.87 * P 0.77 A (mi) P (in)
Q10 10-yr peak flow (m3/S) Q10 = 0.0283 * Q1ocfs Qlocfs (ft3/s) INDEX 10-yr screening index (m1.5/s .5) INDEX = Sv*Q10 0.5 Q1 ( M3/o (m S) Wref Reference width (m) Wref = 6.99 * Q10 0.438 Q10 (m3/s) VWI Valley width index (m/m) VWI = W /Wref W, (m)
Wref (m)
(Sheet 1 of 1)
B - 3
11 /15/2022 PH 1 Page 890 of 1307

SCCWRP FORM 1 ANALYSES
Reach
1 2
3 Reach
1 2
3 Area
Mean Annual Precip.

Valley Slope
Valley Width
10-Year Flow
10-Year Flow
A, sq. mi.

P, inches
Sv, m/m
Wv, m
Q10cfs, cfs
Q10, cros

0.0057

13.09 0.0722

2.44 1.5

0.04 1.0570

13.09 0.0099

9.14 138.4

3.92 1.1557

13.09 0.0136

9.14 149.5

4.23 10-Year Screening Index
INDEX

0.015

0.020

0.028
Reference Width
Wref, m

1.74 12.71

13.15 Valley Width Index
VWI, m/m

1.40 0.72

0.70 11/15/2022 PH1 Page 891 of 1307

StreamStats Report
Region ID: CA
Workspace ID: CA20210804003918730000
Clicked Point (Latitude, Longitude): 33.23230, -117.25114 Time: 2021-08-03 17:39:35 -0700
plo
ome
by Pa rk
L - U
St
Basin Characteristics
Parameter Code Parameter Description
DRNAREA Area that drains to a point on a stream
General Disclaimers
Value Unit

1.0570 square miles
11/15/2022 PH Page 893 of 1307

StreamStats Report
Region ID: CA
Workspace ID: CA20210804003221740000
Clicked Point (Latitude, Longitude): 33.23239,-117.25345 Time: 2021-08-03 17:32:38 -0700
"wAw
1�x
s�
— -I! JL -
FarsLy St
xl C8{I13l'JEI ��Orgo
m
a
Basin Characteristics
Parameter Code Parameter Description
DRNAREA Area that drains to a point on a stream
General Disclaimers
Tr i
AiPCgh1r
Value Unit

1.1557 square miles
11 /15/2022 PH 1 Page 894 of 1307

? ua )CN17@
Park
1 ,1
� 4000
Vista
AV\ C;4�v 4
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11 /15/2022 PH 1 Page 895 of 1307

VISTA 2 NNE, CALIFORNIA (049378)
Period of Record Monthly Climate Summary
Period of Record : 08/01/1957 to 05/12/2016
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual
Average Max. Temperature (F) 67.4 67.8 68.2 70.8 72.9 76.3 81.3 83.0 82.2 77.9 72.3 67.4 74.0 Average Min. Temperature (F) 44.0 45.0 46.3 48.5 53.5 56.6 60.3 61.6 60.0 55.0 48.3 44.0 51.9 Average Total Precipitation 2.76 2.55 2.24 1.05 0.22 0.11 0.06 0.07 0.25 0.54 1.40 1.83 13.09 (in.)
Average Total SnowFall (in.) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Average Snow Depth (in.) 0 0 0 0 0 0 0 0
Percent of possible observations for period of record.

Max. Temp.: 86.6% Min. Temp.: 87% Precipitation: 87.6% Snowfall: 87.7% Snow Depth: 87.3% Check Station Metadata or Metadata graphics for more detail about data completeness.

Western Regional Climate Center, iLrcc@&ri.edu

0.0 0.0 0.0 0.0 0.1
0 0 0 0 0
11 /15/2022 PH 1 Page 896 of 1307

APPENDIX B

SCCWRP FIELD SCREENING DATA
11 /15/2022 PH 1 Page 897 of 1307

Form 3 Support Materials
Form 3 Checklists 1 and 2, along with information recording in Form 3 Table 1, are intended to support the decisions pathways illustrated in Form 3 Overall Vertical Rating for Intermediate/Transitional Bed.

Form 3 Checklist 1: Armoring Potential
❑ A A mix of coarse gravels and cobbles that are tightly packed with 25% surface material of diameter <2 mm
Form 3 Figure 2. Armoring potential photographic supplement for assessing intermediate beds (16 < d50 < 128 mm) to be used in conjunction with Form 3 Checklist 1. (Sheet 2 of 4)
REACH 1, 29 AND 3 RESULTS
B - 7
11 /15/2022 PH 1 Page 898 of 1307

Form 3 Checklist 2: Grade Control
❑ A Grade control is present with spacing 30 cm), no
active mass wasting (analyst cannot say grade control sufficient if mass - wasting checklist indicates presence of bank failure), no exposed bridge pilings, no culverts/structures undermined
• Hard points in serviceable condition at decadal time scale, e.g., no apparent undermining, flanking, failing grout
• If geologic grade control, rock should be resistant igneous and/or metamorphic; For sedimentary/hardpan to be classified as `grade control', it should be of demonstrable strength as indicated by field testing such as hammer test/borings and/or inspected by appropriate stakeholder ❑ B Intermediate to A and C — artificial or geologic grade control present but spaced 2/Sv m to 4/Sv m or potential evidence of failure or hardpan of uncertain resistance
❑ C Grade control absent, spaced >100 m or >4/Sv m, or clear evidence of ineffectiveness
Form 3 Figure 3. Grade -control (condition) photographic supplement for assessing intermediate beds (16 < d50 < 128 mm) to be used in conjunction with Form 3 Checklist 2. (Sheet 3 of 4)
B - 8
11 /15/2022 PH 1 Page 899 of 1307

Regionally -Calibrated Screening Index Threshold for Incising/Braiding For transitional bed channels (d5o between 16 and 128 mm) or labile beds (channel not incised past critical bank height), use Form 3 Figure 3 to determine Screening Index Score and complete Form 3 Table 1.
1 -
o, I
E a' - c128 0.145
Z o 0 96 0.125
o 0.01 � E 80 0.114
UJ m
� 64 0.101
U Al

0.001 y 48 0.087

0.1 1 d5n (mm) 10 100 0 32 0.070
16 0.049
• Stable Braided -F Incising 8 0.031
10% risk 50% risk 90% risk 6 E
� E 4 0.026
-• f • - ••- `L) `9
2 0.022
V
Field -derived: r • 00•-•• - • o 1 0.018

0.5 0.015
Form 3 Figure 4. Probability of incising/braiding based on logistic regression of Screening Index and d5o to be used in conjunction with Form 3 Table 1.

Form 3 Table 1. Values for Screening Index Threshold (probability of incising/braiding) to be used in conjunction with Form 3 Figure 4 (above) to complete Form 3 Overall Vertical Rating for Intermediate/Transitional Bed (below).. Screening Index Score: A = 50% probability of incising/braiding for current Q10, valley slope, and d50- d50 (mm) SV*Q100.5 (m1.5/50.5) o Sv*Q100.5 (m1.5/s0.5) Screening Index Score From Form 2 From Form 1 50/ risk of incising/braiding (A, B, C) from table in Form 3 Figure 3 above
Overall Vertical Rating for Intermediate/Transitional Bed Calculate the overall Vertical Rating for Transitional Bed channels using the formula below.

Numeric values for responses to Form 3 Checklists and Table 1 as follows: A = 3, B = 6, C = 9.

Vertical RtttInarmoring „ grade controi x screening index score Vertical Susceptibility based on Vertical Rating: 7 = HIGH. (Sheet 4 of 4)
B - 9
11/15/2022 PH1 Page 900 of 1307

PEBBLE COUNT
1 2
3 4
5 6
7 8
9 10
11 12
13 14
15 16
17 18
19 20
21 22
23 24
25 26
27 28
29 30
31 32
33 34
35 36
37 38
39 40
41 42
43 Reach 3
Diameter, mm
2 2
2 2
2 2
2 2

2.8 2.8

2.8 2.8
4 4
4 4
4 4
4 4
4 4
4 4
4 4
4 4
4 4
4 4

5.6 5.6

5.6 11 /15/2022 PH 1 Page 901 of 1307

44 45
46 47
48 49
50 51
52 53
54 55
56 57
58 59
60 61
62 63
64 65
66 67
68 69
70 71
72 73
74 75
76 77
78 79
80 81
82 83
84 85
86 87
88 Reach 3
Diameter, mm

5.6 5.6

5.6 8
8 8
8 8
8 8
8 8
8 8
8 8
8 8
8 8
8 8
8 8
8 8
8 8
8 8
8 11
11 11
11 11
11 11
11 11
11 11
11 11 /15/2022 PH 1 Page 902 of 1307

Reach 3
#
Diameter, mm
89 11
90 11
91 11
92 11
93 11
94 16
95 16
96 16
97 16
98 16
99 16
100
16 11 /15/2022 PH 1 Page 903 of 1307

LATERALLY ADJUSTABLE?
no yes IF
LOW
•Fullyarmored 1 Are lateral adjustments occurring?
bedrock bank no yes
stabilization in good
condition
-No evidence Of None, or fluvial only limited to bends and constrictions Mass wasting or extensive fluvial chute formation ! erosion or chute cutoff formation
avulsions
-Fully confined, directly All bank strata consolidated including toe?

HIGH VERY HIGH
coni ected to hillslope, yes n VUVI 2
D ed
Bank
10% logistic 10% logistic risk Coarse ! Fine Fine
risk for angle risk for angle for angle, AND resistant toe, unconsolidated unconsolidated AND VWI 5 2 VWI > 2 d > 54 mm AND VVVI 5 2 AND VWI > 2
Vertical Vertical MED HIGH HIGH VERY Vertical Vertical MEN HIGH HIGH VERY rating rating Vert. Vertical Vertical HIGH rating rating Vert. Vertical Vertical HIGH _ high _ high high high _ high �! high
LOW 11 MEN AREA HIGH LOW MEG MEN HIGH
VW 5 2 VW > 2 VWI 5 2 VW > 2 VWI 5 2 VW > 2 VW s 2 VW > 2

FORM 6: PROBABILITY OF MASS WASTING BANK FAILURE
If mass wasting is not currently extensive and the banks are moderately- to well -consolidated, measure bank height and angle at several locations (i.e., at least three locations that capture the range of conditions present in the study reach) to estimate representative values for the reach. Use Form 6 Figure 1 below to determine if risk of bank failure is >10% and complete Form 6 Table 1. Support your results with photographs that include a protractor/rod/tape/person for scale.

Bank Angle
Bank Height
Corresponding Bank Height for
Bank Failure Risk
(degrees)
(m)
10% Risk of Mass Wasting (m)
( 10% Risk)
Left Bank
Right Bank
O Stable - 10%Risk 50%Risk
4 1 x
l0
IL
5 x
G
� 4
y 2 0 • it
D0 D XX
o 00 O X
v 0o on
aco 00 o a° v
0 30 40
30 7.6
90% Risk x
Unstable
35 4.7
40 3,7
45 2.1
x
X
so

1.5 x
55 1.1
x
60 0.85
X
65 0.66
�c x
x
70 0.52
� x
X
s0

0.34 90

0.24 50 60 70 80 90
Bank Angle (degrees)
Form 6 Figure 1. Probability Mass Wasting diagram, Bank Angle:Height/% Risk table, and Band Height:Angle schematic.
(Sheet 1 of 1)
B-12
11 /15/2022 PH 1 Page 905 of 1307

Critical Flow Calculator
enter all values in green cells
and drop down boxes
Inputs
a) Receiving channel width at top of
bank (ft) - see figure on right
b) Channel width at bed (ft)
c) Bank height at top of bank (ft)
Channel gradient (ft/ft)
Receiving channel roughness
Reach 1
a
c
b
Same as above, but more stones and weeds n=0.035
Channel materials (use weakest of unconsolidated sandy loam 0.035 lb/sq ft bed or banks). If materials are varied alluvial silt (non coloidal) 0.045 lb/sq ft use weakest material covering more medium gravel 0.12 lb/sq ft than 20% of channel. alluvial silt/clay 0.26 lb/sq ft
�2.5 inch cobble 1.1 lb/sq ft
enter own d50 (variable)
veqetation bed and banks 0.6 lb/sq ft
Select method of calculating Q2
Input own Q2
[calculate Q2 using
USGS regression
Receiving water watershed annual

13.09 Receiving water watershed

0.0057
precip (inches)
area at PoC (sq mi)
Project watershed annual

13.09 Project watershed area

0.0057
precipitation (inches)
draining to PoC (sq mi)
Outputs - Flow control range
Point of Compliance low
Receiving water Q2 0.2 flow rate (cfs) 0.1
Project site Q2 0.2 Low flow class 0.5Q2
Channel vulnerability
11 /15/2022 PH 1 Page 906 of 1307

38.0 30.0

2.0 0.0099
Reach 2
a
c
b
Same as above, but more stones and weeds n=0.035
Channel materials (use weakest of unconsolidated sandy loam 0.035 lb/sq ft bed or banks). If materials are varied alluvial silt (non coloidal) 0.045 lb/sq ft use weakest material covering more medium gravel 0.12 lb/sq ft than 20% of channel. alluvial silt/clay 0.26 lb/sq ft
�2.5 inch cobble 1.1 lb/sq ft
enter own d50 (variable)
veqetation bed and banks 0.6 lb/sq ft
Select method of calculating Q2
Input own Q2
[calculate Q2 using
USGS regression
Receiving water watershed annual

13.09 Receiving water watershed

1.0570
precip (inches)
area at PoC (sq mi)
Project watershed annual

13.09 Project watershed area

1.0570
precipitation (inches)
draining to PoC (sq mi)
Outputs - Flow control range
Point of Compliance low
Receiving water Q2 9.4 flow rate (cfs) 4.7
Project site Q2 9.4 Low flow class 0.502
Channel vulnerability •
11 /15/2022 PH 1 Page 907 of 1307

38.0 30.0

2.0 0.0136
Reach 3
a
c
b
Same as above, but more stones and weeds n=0.035
Channel materials (use weakest of unconsolidated sandy loam 0.035 lb/sq ft bed or banks). If materials are varied alluvial silt (non coloidal) 0.045 lb/sq ft use weakest material covering more medium gravel 0.12 lb/sq ft than 20% of channel. alluvial silt/clay 0.26 lb/sq ft
�2.5 inch cobble 1.1 lb/sq ft
enter own d50 (variable)
veqetation bed and banks 0.6 lb/sq ft
Select method of calculating Q2
Input own Q2
[calculate Q2 using
USGS regression
Receiving water watershed annual

13.09 Receiving water watershed

1.1557
precip (inches)
area at PoC (sq mi)
Project watershed annual

13.09 Project watershed area

1.1557
precipitation (inches)
draining to PoC (sq mi)
Outputs - Flow control range
Point of Compliance low
Receiving water Q2 10.0 flow rate (cfs) 5.0
Project site Q2 10.0 Low flow class 0.5Q2
Channel vulnerability
11 /15/2022 PH 1 Page 908 of 1307

GRAPHIC SCALE
100 0 50 100 200
1 INCH = 100 FEET
MEN-
7 29i.

PE 334.5
334.E
PE *5
KIM
�� 6
`-'__PROPOSED STORM DRAIN
FROM PROJECT -_. _• �t
PE
LEGEND:

DOWNSTREAM DOMAIN OF ANALYSIS J
��OCATION FOR REACH 1 AT CONFLUEN
vOF NATURAL SWALE WITH UNNAMED
%NATURAL � DRAINAGE COURS it
DRAINAGE BASIN BOUNDARY TRIBUTARY TO REACH 1

3.29 AC DRAINAGE BASIN AREA

PROPOSED PROJECT

PROPOSED DRAINAGE FACILITY

EXISTING DRAINAGE FACILITY

STUDY REACH

CAMINO LARGO

STUDY AREA EXHIBIT
11/15/2022 PH1 Page 909 of 1307

ATTACHMENT 2D— FLOW CONTROL FACILITY DESIGN

Page 54 of 73 ends

11 /15/2022 PH 1 Page 910 of 1307

HYDROMODIFICATION MANAGEMENT PLAN (HMP)
SWMM Modeling for Hydromodification Compliance of:

CAMINO LARGO
2123 N. Santa Fe Ave
Vista, CA 92084
APN: 159-240-07
Prepared For:

Kyun Tae Kim
Frank Sohaei, Trustee of the Falor Family Trust
2359 Pio Pico Drive
Carlsbad, CA 92008
(760) 420-1267
December 6, 2021
Prepared By:

Bruce Rice, R.C.E. 60676 Expires 12/31 /22
9910VEssrov�
Date C 60676�
Ui ;U
bhA. Inc
land planning, civil engineering, surveying
5115 Avenida Encinas, Suite L
Carlsbad, CA 92008-4387
(760) 931-8700
W.O. 944-1154-401
STgr�OF CAL
1 11 /15/2022 PH 1

Page 911 of 1307 ends

HYDROMODIFICATION MANAGEMENT PLAN (HMP)
SWMM Modeling for Hydromodification Compliance of:

Camino Largo Project, City of Vista, CA

INTRODUCTION
This document summarizes the approach used to model the proposed Camino Largo project site in the City of Vista using the Environmental Protection Agency (EPA) Storm Water Management Model 5.1 (SWMM). SWMM simulations were prepared for the pre and post -development conditions at the site in order to determine if the proposed LID biofiltration facilities have sufficient volume to meet the current Hydromodification Management Plan (HMP) requirements from the San Diego Regional Water Quality Control Board (SDRWQCB), as established in the Model BMP Design Manual San Diego Region (BMPDM) for the County of San Diego Copermittees, which includes the City of Vista.

SWMM MODEL DEVELOPMENT
The Camino Largo Project proposes the development of a forty six (46) lot residential subdivision, with individual level building pads, driveways and landscaping areas on 8.86 gross acres. The project also proposes the minor widening and improvement of the Camino Largo private drive, which will include paving, sidewalks with curb and gutter. Approximately 53% of the property will be impervious. Biofiltration basins are proposed for the two main drainage basins for POC-1 and POC-2. Proposed grading has been minimized as much as possible to maintain existing slope and drainage patterns.

POC-1
There is one (1) biofiltration basin proposed, which will outlet into an existing storm drain along -side North Santa Fe Avenue south of Camino Largo and discharge from the site at POC-1.

POC-2
There is one (1) proposed biofiltration basin, which outlets via a storm drain into a natural swale at POC-2.

Two (2) SWMM simulations were prepared for each POC in the study: the first for pre -development and the second for the post -developed conditions.

The development drainage patterns reflected on the DMA Exhibit will remain approximately the same acreage draining to the southwest corner (POC-1), while acreage is increased in the post -development condition in the southeast corner (POC-2). Both POCs include impervious contributing area and require SWMM continuous simulation analysis to prove compliance with HMP requirements. 11 /15/2022 PH 1 Page 912 of 1307

TABLE 1—CONTRIBUTING AREA —PRE-DEVELOPMENT VS. POST -DEVELOPMENT POC ID
Pre-Dev Area (Ac)
Post-Dev Area (Ac)
Difference
POC 1

4.952

4.847
-0.104
POC 2

4.153

5.055

0.902
The SWMM was used since we have found it to be more comparable to San Diego area watersheds than the alternative San Diego Hydrology Model (SDHM) and also because it is a non-proprietary model approved by the HMP document. For both SWMM simulations, flow duration curves were prepared to determine if the proposed HMP facilities are sufficient to meet the current HMP requirements.

The inputs required to develop SWMM simulations include rainfall, watershed characteristics, and BMP configuration. The Oceanside Gage from the Project Clean Water website was used for this study, since it is the most representative of the project site precipitation due to elevation and proximity to the project site.

Per the California Irrigation Management Information System "Reference Evaporation Zones" (CIMIS ETo Zone Map), the project site is located within the Zone 4 Evapotranspiration Area. Thus evapotranspiration values for the site were modeled using Zone 4 monthly values from Table G.1-1 from the City of Vista BMP Design Manual.

The on -site soil classification is Type C and Type D from USDA Web Soil Survey. Type D soils will be used in POC-1 and POC-2 because it is the main soils type in each DMA (see References).

Onsite soil areas have been assumed to be non -compacted in the existing condition to represent the current condition of the site and fully compacted in the post development conditions. Other SWMM inputs for subareas are discussed in the appendices to this document, where the selection of the parameters is explained in detail.

HMP MODELING
POC-1
DMA 1 will drain into a biofiltration basin which will outlet into an existing storm drain along -side North Santa Fe Avenue south of Camino Largo and discharge from the site at POC-1. Once flows are routed via the proposed BMP, the flow is then conveyed via storm drain to the aforementioned POC. Tables 2.1 and 2.2 summarize data for the POC-1 DMAs.

TABLE 2.1—SUMMARY OF EXISTING CONDITIONS FOR POC-1
Impervious
DMA
Tributary Area, A (Ac)
Percentage, Ip
DMA 1

4.952

0.00%
TOTAL

4.952
-
11 /15/2022 PH 1 Page 913 of 1307

TABLE 2.2 —SUMMARY OF DEVELOPED CONDITIONS FOR POC-1
DMA
Tributary Area, A (Ac)
Impervious
Percentage, Ip
DMA 1

4.706

58.42%
BMP 1

0.141

0.00%
TOTAL

4.847
-
(1) BMP Areas are separate from the overall DMA to ensure areas are not double counted.

POC-2
There is one (1) proposed biofiltration basin, which outlets via a storm drain into a natural swale at POC-2.

Once flows are routed via the proposed BMPs, flows are then conveyed via storm drain to the aforementioned POC.

Tables 2.3 and 2.4 summarize data for the POC-2 DMAs.

TABLE 2.3 —SUMMARY OF EXISTING CONDITIONS FOR POC-2
DMA
Tributary Area, A (Ac)
Impervious
Percentage, Ip
DMA 2

3.121

0.00%
BYPASS 1

1.031

0.00%
TOTAL

4.153
-
TABLE 2.4—SUMMARY OF DEVELOPED CONDITIONS FOR POC-2
DMA
Tributary Area, A (Ac)
Impervious
Percentage, Ip
DMA 2

3.146

57.73%
BMP 2

0.213

0.00%
BYPASS 2

1.696

0.00%
TOTAL

5.055
-
(1) BMP Areas are separate from the overall DMA to ensure areas are not double counted.

Biofiltration basins in 1 and 2 are responsible for handling hydromodification requirements for POC-1 and POC-2.

Basins 1 and Basin 2 will have a ponding depth of 6 inches. BMPs are comprised of an 18-inch layer of amended soil (a highly sandy, organic rich compost with an infiltration capacity of at least 5 in/hr), and a 7-inch reservoir layer of gravel for additional detention, and to accommodate the French drain system. Below the reservoir layer, the basins will include 3 inches of saturated storage. Flows will discharge from the basin via a low -flow orifice outlet within the gravel layer to the receiving storm drain system. A riser structure will be constructed within the BMP with multiple low -flow orifices and an emergency overflow, such that peak flows can be safely discharged to the storm drain system (see dimensions in Table 3 and 4).
11 /15/2022 PH 1 Page 914 of 1307

General Considerations
The biofiltration basins (BMP 1 and BMP 2) were modeled using the biofiltration LID module within SWMM. The biofiltration module can model the underground gravel storage layer, underdrain with orifice plate, amended soil layer, and a surface storage pond up to the elevation of the invert of the lowest surface discharge opening in the basin riser structure. Ponding above the invert of the lowest surface discharge opening in the basin riser structure is modeled as a detention basin: elevation vs. area, and elevation vs. discharge tables, are needed by SWMM for Modified Puls routing purposes. Detailed outlet structure location and elevations should be shown on the construction plans based on the recommendations of this study.

BMP MODELING FOR HMP PURPOSES
Modeling of dual purpose Water Quality/HMP IMP
HMP-BMP biofiltration basins are proposed for hydromodification conformance and flood control for the project site. Tables 3 and 4 illustrate the dimensions required for HMP compliance according to the SWMM model that was undertaken for the project. Flood control is discussed within the Drainage Report prepared by BHA for this project.

TABLE 3 —SUMMARY OF DUAL PURPOSE BMP: Biofiltration with Surface Ponding Dimensions
Biofiltration
Tributary
BMP
Underdrain
Total
Riser
Min.

BMP
Area (Ac)
Area(l)
Orifice, D(�)
Gravel
Invert
Total
ft2
in
De th(3)
Elev,
Surface
BMP 1

4.706
6,147

4.00 7
18 12
BMP 2

3.121
1 9,279

3.00 7
18 12
Notes: (1):Area of amended soil =area of gravel =area of BMP. (2): Diameter of the orifice in gravel layer with invert at bottom of layer; tied with hydromod min threshold (50%Q2).
(3): Total depth of gravel including 3" of saturated storage located below (4): Depth from bottom of pond to invert of emergency overflow weir.

TABLE 4—SUMMARY HMP RISER SURFACE DISCHARGE STRUCTURES
Lower Slot Dimensions
Upper Slot Dimensions
Emergency Weir
Biofiltration
Invert
Invert
(#) - Width
Riser
Weir
Outlet
(#) - Width x
Outlet
BMP
(1)
Elev, HL(Z)
(3i
(11
Elev, HL(�)
x Height
Invert
Perimeter
Type
(in)
Height (in)
Type
(in)
(3)
(in)
Elev,
Length (s)
BMP 1
Slot
6 (1) - 34 x 5
Slot
7 (1) - 10 x 4
18 11.83
BMP 2
Slot
6 (1) - 32 x 3
Slot
7 (1) - 6 x 2
18 11.83
Notes: (1): Shape of orifice opening in riser structure. (2): Depth from bottom of pond to invert of lower slot or weir. (3): Number of slots and slot dimensions: For example for BMP 1: Two 29-inch wide by 3-inch high slots at 6-inches above bottom of basin and one 10-inch wide by 3-inch high slot at 7-inches above bottom of basin.
(4): Depth from bottom of pont to invert of emergency overflow weir. (5): Overflow length, the internal perimeter of the riser. 11 /15/2022 PH 1 Page 915 of 1307

FLOW DURATION CURVE COMPARISON
The Flow Duration Curve (FDC) for the site was compared at POC-1 and POC-2 by exporting the hourly runoff time series results from SWMM to a spreadsheet. At both POCs, the FDC was compared between 10% of the existing condition Q2 up to the existing condition Q1o. The Q2 and Q10 were determined using a partial duration statistical analysis of the runoff time series in an Excel spreadsheet using the Weibull plotting position method.

The range between 10% of Q2 and Q10 was divided into 100 equal time intervals; the number of hours that each flow rate was exceeded was counted from the hourly series. Additionally, the intermediate peaks with a return period "I" were obtained (Qi with i=3 to 9). For the purpose of the plot, the values were presented as percentage of time exceeded for each flow rate. FDC comparison at POC-1 and POC-2 is illustrated in Figure 1 and Figure 2, respectively, in both normal and logarithmic scale.

As can be seen in Figure 1 and Figure 2, the FDCs for the proposed condition with the HMP facilities is within 110% of the curve for the existing condition in both peak and duration. The additional runoff volume generated from developing the site will be released to the existing point of discharge at a flow rate below the 10% Q2 lower threshold. Additionally, the project will also not increase peak flow rates between the pre -development Q2 and the Qio, as shown in the graphic and also in the peak flow tables listed in Attachment 1.

Discussion of the Manning's coefficient (Pervious Areas) for Pre and Post -Development Conditions Typically the Manning's coefficient is selected as n = 0.15 for pervious areas and n = 0.012 for impervious areas (as consistent with the BMP Design Manual). However, due to the impact that n has in the continuous simulation a more accurate value of the Manning's coefficient has been chosen for pervious areas. Taken into consideration the study prepared by Tory R. Walker Engineering (Reference [6]) a value of n = 0.08 has been selected (see Table 1 of Reference [6] included in Attachment 7). The existing condition site includes paved driveways and impervious accessory buildings. Existing impervious areas are assumed to be pervious areas consisting of the bare soil underlying the impervious surfaces. Therefore the existing condition site is primarily a mix of bare dirt and shrubs.

Based on these existing site observations, the N value was conservatively selected as 0.08, which is consistent per the reference cited. The BMP Design Manual default value of n = 0.10 was used for the developed portions of the project, as the developed site is assumed to include dense landscaping.

DRAWDOWN TIME
To ensure compliance with the 24 hour and 96 hour drawdown requirements (per Section 6.3.7 of the BMP Design Manual); drawdown calculations are provided in Attachment 10 of this report.

SUMMARY
This study has demonstrated that the proposed biofiltration basins provided for the Camino Largo Project site are sufficient to meet current HMP criteria if the cross-section areas and volumes recommended within this document, and the respective orifice and outlet structures are incorporated as specified within the proposed project site. 11 /15/2022 PH 1 Page 916 of 1307

KEY ASSUMPTIONS

1. No infiltration test were performed. Infiltration for the site is considered low and within the range of Type D soils.

2. The biofiltration basins will be lined with an impermeable liner (no infiltration).

ATTACHMENTS

1. Qz to Q10 Comparison Tables

2. FDC Plots (log and natural "x" scale) and Flow Duration Table

3. List of the "n" largest Peaks: Pre -Development and Post -Development Conditions

4. Elevations vs. Discharge & Stage- Storage Curves to be used in SWMM

5. Basin Outlet Structure Details

6. SWMM Input Data in Input Format (Existing and Proposed Models)

7. SWMM Screens and Explanation of Significant Variables

8. Geotechnical Documentation

9. Summary files from the SWMM Model

10. Drawdown calculations
11 /15/2022 PH 1 Page 917 of 1307

REFERENCES
[1] — "City of Vista BMP Design Manual", June 2016, City of Vista. [2] — "Final Hydromodification Management Plan (HMP) prepared for the County of San Diego", March 2011, Brown and Caldwell.
[3] — Order R9-2013-001, California Regional Water Quality Control Board San Diego Region (SDRWQCB). [4] — "Review and Analysis of San Diego County Hydromodification Management Plan (HMP): Assumptions, Criteria, Methods, & Modeling Tools — Prepared for the Cities of San Marcos, Oceanside & Vista", May 2012, Tory R. Walker Engineering.
[5] — "San Diego County Hydraulic Design Manual', September 2014, County of San Diego Department of Public Works Flood Control Section.
[6] — "Improving Accuracy in Continuous Hydrologic Modeling: Guidance for Selecting Pervious Overland Flow Manning's n Value in the San Diego Region", Tory R. Walker Engineering, 2016. [7] — "Priority Development Project (PDP) Storm Water Quality Management Plan (SWAMP) for 1017 Sycamore Avenue", March 18, 2020, BHA, Inc.
11 /15/2022 PH 1 Page 918 of 1307

Figure 1a and 1b. POC-1 Flow Duration Curve Comparison (logarithmic and normal "x" scale) Camino Largo, Vista, Ca - POC-1 Flow Duration Curve

5.000

4.500

4.000

3.500
'
-
- -

3.000
0 2.500

2.000

1.500

1.000
-

0.500
- - - Pre -project Q
- Post -project (Mitigated) Q

0.000

1.0E-06 1.0E-05 1.0E-04 1.0E-03
%Time Exceeding

5.000

4.500

4.000

3.500
L

3.000
3 0

2.500

2.000

1.500

1.000

0.500

0.000

1.0E-06
11 /15/2022
Camino Largo, Vista, Ca - POC-1 Flow Duration Curve

1.0E-05 1.0E-04 1.0E-03
%Time Exceeding
PH 1 Page 919 of 1307

Figure 2a and 2b. PCIC-2 Flow Duration Curve Comparison (logarithmic and normal "x" scale) Camino Largo, Vista, Ca - POC-2 Flow Duration Curve

3.500

3.000

2.500
3 2.000

1.500

1.000

0.500
- - -
Pre-projectQ
-Post-project (Mitigated) Q

0.000

1.0E-06 1.0E-05 1.0E-04 1.0E-03
%Time Exceeding

8.000

7.000

6.000

5.000
Y^
3 0
W 4.000

3.000

2.000

1.000

0.000

3.0E-08
11 /15/2022
Camino Largo, Vista, Ca - POC-2 Flow Duration Curve

3.1E-04 6.2E-04 9.3E-04 1.2E-03
%Time Exceeding
PH1

1.6E-03 1.9E-03

Page 920 of 1307 ends

ATTACHMENT 1
Q2 to Qso Comparison Tables
11 /15/2022 Pik 1 Page 921 of 1307

Peak Flow Frequency Summary - POC-1
Q2 to Qlo Comparison Table - POC-1
Return Period
Existing Condition (cfs)
Mitigated Condition
(cfs)
Reduction, Exist -
Mitigated (cfs)
LF = 0.1xQ2

1.318

0.987

0.331
2-year

2.635

1.973

0.662
3-year

2.847

2.317

0.530
4-year

3.262

2.696

0.566
5-year

3.346

2.914

0.432
6-year

3.446

3.051

0.395
7-year

3.648

3.132

0.517
8-year

3.737

3.160

0.577
9-year

3.985

3.169

0.817
10-year

4.249

3.216

1.033
Peak Flow Frequency Summary - POC-2
Q2 to Qlo Comparison Table - POC-2
Return Period
Existing Condition (cfs)
Mitigated Condition
(cfs)
Reduction, Exist -
Mitigated (cfs)
LF = 0.1xQ2

1.112

0.474

0.638
2-year

2.224

0.948

1.276
3-year

2.398

1.032

1.366
4-year

2.744

1.166

1.578
5-year

2.825

1.208

1.617
6-year

2.896

1.247

1.648
7-year

3.063

1.315

1.748
8-year

3.138

1.349

1.789
9-year

3.369

1.427

1.942
10-year

3.603

1.513

2.090
11 /15/2022 PH 1 Page 922 of 1307

ATTACHMENT 2
FDC Plots (log and natural 'Y' scale) and Flow Duration Table 11 /15/2022 PH 1 Page 923 of 1307

Flow Duration Curve Analysis
1) Flow duration curve shall not exceed the existing conditions by more than 10%, neither in peak flow nor duration.

The figures on the following pages illustrate that the flow duration curve in post -development conditions after the proposed BMP is below the existing flow duration curve. The flow duration curve table following the curve shows that if the interval 0.1Q2 — Qio is divided into 100 sub intervals, the post development divided by pre -development durations is never larger than 110% (the permit allows up to 110%) Consequently, the design passes the hydromodification test.

It is important to note that the flow duration curve can be expressed in the "x" axis as percentage of time, hours per year, total number of hours, or any other similar time variable. As those variables only differ by a multiplying constant, their plot in logarithmic scale is going to look exactly the same, and compliance can be observed regardless of the variable selected. However, in order to satisfy the County of San Diego HMP example, % of time exceeded is the variable of choice in the flow duration curve. The selection of a logarithmic scale in lieu of the normal scale is preferred, as differences between the pre -development and post -development curves can be seen more clearly in the entire range of analysis. Both graphics are presented just to prove the difference.

In terms of the "y" axis, the peak flow value is the variable of choice. As an additional analysis performed by BHA, not only the range of analysis is clearly depicted (50% of Q2 to Qlo) but also all intermediate flows are shown (Q2, Q3, Q4, Qs, Q6, Q7, Qs, and Q9) in order to demonstrate compliance at any range Qx — Q,1.

It must be pointed out that one of the limitations of both the SWMM and SDHM models is that the intermediate analysis is not performed (to obtain Q; from i = 2 to 10). BHA performed the analysis using the Weibull Plotting positon Method from the "n" largest independent peak flows obtained from the continuous time series.

The largest "n" peak flows are attached in this appendix, as well as the values of Q; with a return period "i", from i = 2 to 10. The Q, values are also added into the flow -duration plot. 11 /15/2022 PH 1 Page 924 of 1307

Flow Duration Curve Data for Camino Largo POC-1, Vista, CA Low Flow Threshold: 50%

0.1xQ2 (Pre): 1.318 cfs
Q10 (Pre): 4.249 cfs
# of Ordinates: 100
Incremental Q(Pre): 0.02931 cfs
Total Hourly Data: 497370 hours
The proposed BMP: PASSED
Interval
Pre -project
Flow (cfs)
Pre -project
Hours
Pre -project
% Time
Exceeding
Post -project
Hours
Post -project
% Time
Exceeding
Percentage
Pass/Fail
0 1.318
145

2.92E-04
79 1.59E-04
54%
Pass
1 1.347
134

2.69E-04
72 1.45E-04
54%
Pass
2 1.376
126

2.53E-04
68 1.37E-04
54%
Pass
3 1.405
126

2.53E-04
64 1.29E-04
51%
Pass
4 1.435
120

2.41E-04
61 1.23E-04
51%
Pass
5 1.464
117

2.35E-04
58 1.17E-04
50%
Pass
6 1.493
116

2.33E-04
55 1.11E-04
47%
Pass
7 1.523
113

2.27E-04
54 1.09E-04
48%
Pass
8 1.552
111

2.23E-04
54 1.09E-04
49%
Pass
9 1.581
110

2.21E-04
54 1.09E-04
49%
Pass
10 1.611
103

2.07E-04
54 1.09E-04
52%
Pass
11 1.640
98 1.97E-04
54 1.09E-04
55%
Pass
12 1.669
93 1.87E-04
52 1.05E-04
56%
Pass
13 1.699
89 1.79E-04
48 9.65E-05
54%
Pass
14 1.728
83 1.67E-04
46 9.25E-05
55%
Pass
15 1.757
81 1.63E-04
45 9.05E-05
56%
Pass
16 1.786
75 1.51E-04
44 8.85E-05
59%
Pass
17 1.816
71 1.43E-04
42 8.44E-05
59%
Pass
18 1.845
65 1.31E-04
41 8.24E-05
63%
Pass
19 1.874
64 1.29E-04
38 7.64E-05
59%
Pass
20 1.904
62 1.25E-04
36 7.24E-05
58%
Pass
21 1.933
62 1.25E-04
36 7.24E-05
58%
Pass
22 1.962
61 1.23E-04
36 7.24E-05
59%
Pass
23 1.992
58 1.17E-04
35 7.04E-05
60%
Pass
24 2.021
57 1.15E-04
34 6.84E-05
60%
Pass
25 2.050
54 1.09E-04
33 6.63E-05
61%
Pass
26 2.080
1 52

1.05E-04
j 31
j 6.23E-05
j 60%
j Pass
27 2.109
1 49

9.85E-05
1 31
1 6.23E-05
1 63%
Pass
11 /15/2022 PH 1 Page 925 of 1307

28 2.138
48 9.65E-05
30 6.03E-05
63%
Pass
29 2.168
48 9.65E-05
30 6.03E-05
63%
Pass
30 2.197
46 9.25E-05
27 5.43E-05
59%
Pass
31 2.226
44 8.85E-05
24 4.83E-05
55%
Pass
32 2.255
42 8.44E-05
22 4.42E-05
52%
Pass
33 2.285
42 8.44E-05
21 4.22E-05
50%
Pass
34 2.314
41 8.24E-05
21 4.22E-05
51%
Pass
35 2.343
41 8.24E-05
20 4.02E-05
49%
Pass
36 2.373
40 8.04E-05
19 3.82E-05
48%
Pass
37 2.402
39 7.84E-05
19 3.82E-05
49%
Pass
38 2.431
39 7.84E-05
19 3.82E-05
49%
Pass
39 2.461
39 7.84E-05
19 3.82E-05
49%
Pass
40 2.490
37 7.44E-05
19 3.82E-05
51%
Pass
41 2.519
35 7.04E-05
18 3.62E-05
51%
Pass
42 2.549
33 6.63E-05
18 3.62E-05
55%
Pass
43 2.578
33 6.63E-05
17 3.42E-05
52%
Pass
44 2.607
33 6.63E-05
17 3.42E-05
52%
Pass
45 2.637
32 6.43E-05
17 3.42E-05
53%
Pass
46 2.666
31 6.23E-05
17 3.42E-05
55%
Pass
47 2.695
31 6.23E-05
16 3.22E-05
52%
Pass
48 2.724
30 6.03E-05
15 3.02E-05
50%
Pass
49 2.754
29 5.83E-05
15 3.02E-05
52%
Pass
50 2.783
25 5.03E-05
15 3.02E-05
60%
Pass
51 2.812
22 4.42E-05
15 3.02E-05
68%
Pass
52 2.842
22 4.42E-05
15 3.02E-05
68%
Pass
53 2.871
21 4.22E-05
14 2.81E-05
67%
Pass
54 2.900
21 4.22E-05
13 2.61E-05
62%
Pass
55 2.930
21 4.22E-05
13 2.61E-05
62%
Pass
56 2.959
21 4.22E-05
13 2.61E-05
62%
Pass
57 2.988
21 4.22E-05
12 2.41E-05
57%
Pass
58 3.018
21 4.22E-05
12 2.41E-05
57%
Pass
59 3.047
21 4.22E-05
11 2.21E-05
52%
Pass
60 3.076
21 4.22E-05
11 2.21E-05
52%
Pass
61 3.106
20 4.02E-05
11 2.21E-05
55%
Pass
62 3.135
20 4.02E-05
10 2.01E-05
50%
Pass
63 3.164
20 4.02E-05
8 1.61E-05
40%
Pass
64 3.193
19 3.82E-05
6 1.21E-05
32%
Pass
65 3.223
18 3.62E-05
6 1.21E-05
33%
Pass
66 3.252
15 3.02E-05
6 1.21E-05
40%
Pass
67 3.281
15 3.02E-05
6 1.21E-05
40%
Pass
68 3.311
13 2.61E-05
6 1.21E-05
46%
Pass
69 3.340
11 2.21E-05
6 1.21E-05
55%
Pass
70 3.369
10 2.01E-05
6 1.21E-05
60%
Pass
11 /15/2022 PH 1 Page 926 of 1307

71 3.399
9 1.81E-05
6 1.21E-05
67%
Pass
72 3.428
9 1.81E-05
5 1.01E-05
56%
Pass
73 3.457
9 1.81E-05
4 8.04E-06
44%
Pass
74 3.487
9 1.81E-05
4 8.04E-06
44%
Pass
75 3.516
9 1.81E-05
4 8.04E-06
44%
Pass
76 3.545
9 1.81E-05
4 8.04E-06
44%
Pass
77 3.575
9 1.81E-05
4 8.04E-06
44%
Pass
78 3.604
8 1.61E-05
4 8.04E-06
50%
Pass
79 3.633
8 1.61E-05
4 8.04E-06
50%
Pass
80 3.662
8 1.61E-05
4 8.04E-06
50%
Pass
81 3.692
7 1.41E-05
4 8.04E-06
57%
Pass
82 3.721
7 1.41E-05
4 8.04E-06
57%
Pass
83 3.750
7 1.41E-05
4 8.04E-06
57%
Pass
84 3.780
6 1.21E-05
4 8.04E-06
67%
Pass
85 3.809
6 1.21E-05
4 8.04E-06
67%
Pass
86 3.838
6 1.21E-05
4 8.04E-06
67%
Pass
87 3.868
6 1.21E-05
4 8.04E-06
67%
Pass
88 3.897
6 1.21E-05
4 8.04E-06
67%
Pass
89 3.926
6 1.21E-05
4 8.04E-06
67%
Pass
90 3.956
6 1.21E-05
4 8.04E-06
67%
Pass
91 3.985
6 1.21E-05
4 8.04E-06
67%
Pass
92 4.014
6 1.21E-05
4 8.04E-06
67%
Pass
93 4.044
6 1.21E-05
4 8.04E-06
67%
Pass
94 4.073
6 1.21E-05
4 8.04E-06
67%
Pass
95 4.102
6 1.21E-05
4 8.04E-06
67%
Pass
96 4.131
6 1.21E-05
4 8.04E-06
67%
Pass
97 4.161
6 1.21E-05
4 8.04E-06
67%
Pass
98 4.190
6 1.21E-05
4 8.04E-06
67%
Pass
99 4.219
5 1.01E-05
4 8.04E-06
80%
Pass
100

4.249
5 1.01E-05
4 8.04E-06
80%
Pas--1
11 /15/2022 PH 1 Page 927 of 1307

Peak flows calculated with the Weibull Plotting Position Return Period
(years)
Pre-Dev. Peak
Flows (cfs)
Post-Dev.

Peak Flows(cfs)
Reduction
(cfs)
LF = 0.1xQ2

1.318

0.987

0.331
2-year

2.635

1.973

0.662
3-year

2.847

2.317

0.530
4-year

3.262

2.696

0.566
5-year

3.346

2.914

0.432
6-year

3.446

3.051

0.395
7-year

3.648

3.132

0.517
8-year

3.737

3.160

0.577
9-year

3.985

3.169

0.817
10-year

4.249

3.216

1.033
11 /15/2022 PH 1 Page 928 of 1307

Flow Duration Curve Data for Camino Largo POC-2, Vista, CA Low Flow Threshold: 50%

0.1xQ2 (Pre): 1.112 cfs
Q10 (Pre): 3.603 cfs
# of Ordinates: 100
Incremental Q(Pre): 0.02491 cfs
Total Hourly Data: 497370 hours
The proposed BMP: PASSED
Interval
Pre -project
Flow (cfs)
Pre -project
Hours
Pre -project
% Time
Exceeding
Post -project
Hours
Post -project
% Time
Exceeding
Percentage
Pass/Fail
0 1.112
149

3.00E-04
21 4.22E-05
14%
Pass
1 1.137
139

2.79E-04
18 3.62E-05
13%
Pass
2 1.162
130

2.61E-04
16 3.22E-05
12%
Pass
3 1.187
127

2.55E-04
14 2.81E-05
11%
Pass
4 1.212
123

2.47E-04
11 2.21E-05
9%
Pass
5 1.237
120

2.41E-04
9 1.81E-05
8%
Pass
6 1.261
117

2.35E-04
9 1.81E-05
8%
Pass
7 1.286
116

2.33E-04
9 1.81E-05
8%
Pass
8 1.311
113

2.27E-04
8 1.61E-05
7%
Pass
9 1.336
110

2.21E-04
7 1.41E-05
6%
Pass
10 1.361
106

2.13E-04
6 1.21E-05
6%
Pass
11 1.386
100

2.01E-04
6 1.21E-05
6%
Pass
12 1.411
94 1.89E-04
6 1.21E-05
6%
Pass
13 1.436
90 1.81E-04
6 1.21E-05
7%
Pass
14 1.461
86 1.73E-04
6 1.21E-05
7%
Pass
15 1.486
80 1.61E-04
6 1.21E-05
8%
Pass
16 1.511
74 1.49E-04
5 1.01E-05
7%
Pass
17 1.535
71 1.43E-04
5 1.01E-05
7%
Pass
18 1.560
67 1.35E-04
5 1.01E-05
7%
Pass
19 1.585
66 1.33E-04
5 1.01E-05
8%
Pass
20 1.610
65 1.31E-04
5 1.01E-05
8%
Pass
21 1.635
62 1.25E-04
4 8.04E-06
6%
Pass
22 1.660
62 1.25E-04
4 8.04E-06
6%
Pass
23 1.685
59 1.19E-04
4 8.04E-06
7%
Pass
24 1.710
57 1.15E-04
3 6.03E-06
5%
Pass
25 1.735
54 1.09E-04
2 4.02E-06
4%
Pass
26 1.760
50 1.01E-04
2 4.02E-06
4%
Pass
27 1.785
50 1.01E-04
2 4.02E-06
4%
Pass
11 /15/2022 PH 1 Page 929 of 1307

28 1.809
49 9.85E-05
2 4.02E-06
4%
Pass
29 1.834
48 9.65E-05
2 4.02E-06
4%
Pass
30 1.859
46 9.25E-05
1 2.01E-06
2%
Pass
31 1.884
44 8.85E-05
1 2.01E-06
2%
Pass
32 1.909
43 8.65E-05
1 2.01E-06
2%
Pass
33 1.934
42 8.44E-05
0 0.00E+00
0%
Pass
34 1.959
41 8.24E-05
0 0.00E+00
0%
Pass
35 1.984
41 8.24E-05
0 0.00E+00
0%
Pass
36 2.009
40 8.04E-05
0 0.00E+00
0%
Pass
37 2.034
39 7.84E-05
0 0.00E+00
0%
Pass
38 2.059
39 7.84E-05
0 0.00E+00
0%
Pass
39 2.083
39 7.84E-05
0 0.00E+00
0%
Pass
40 2.108
37 7.44E-05
0 0.00E+00
0%
Pass
41 2.133
35 7.04E-05
0 0.00E+00
0%
Pass
42 2.158
33 6.63E-05
0 0.00E+00
0%
Pass
43 2.183
33 6.63E-05
0 0.00E+00
0%
Pass
44 2.208
33 6.63E-05
0 0.00E+00
0%
Pass
45 2.233
32 6.43E-05
0 0.00E+00
0%
Pass
46 2.258
31 6.23E-05
0 0.00E+00
0%
Pass
47 2.283
31 6.23E-05
0 0.00E+00
0%
Pass
48 2.308
29 5.83E-05
0 0.00E+00
0%
Pass
49 2.333
29 5.83E-05
0 0.00E+00
0%
Pass
50 2.357
22 4.42E-05
0 0.00E+00
0%
Pass
51 2.382
22 4.42E-05
0 0.00E+00
0%
Pass
52 2.407
22 4.42E-05
0 0.00E+00
0%
Pass
53 2.432
21 4.22E-05
0 0.00E+00
0%
Pass
54 2.457
21 4.22E-05
0 0.00E+00
0%
Pass
55 2.482
21 4.22E-05
0 0.00E+00
0%
Pass
56 2.507
21 4.22E-05
0 0.00E+00
0%
Pass
57 2.532
21 4.22E-05
0 0.00E+00
0%
Pass
58 2.557
21 4.22E-05
0 0.00E+00
0%
Pass
59 2.582
21 4.22E-05
0 0.00E+00
0%
Pass
60 2.607
21 4.22E-05
0 0.00E+00
0%
Pass
61 2.631
20 4.02E-05
0 0.00E+00
0%
Pass
62 2.656
20 4.02E-05
0 0.00E+00
0%
Pass
63 2.681
19 3.82E-05
0 0.00E+00
0%
Pass
64 2.706
18 3.62E-05
0 0.00E+00
0%
Pass
65 2.731
15 3.02E-05
0 0.00E+00
0%
Pass
66 2.756
15 3.02E-05
0 0.00E+00
0%
Pass
67 2.781
13 2.61E-05
0 0.00E+00
0%
Pass
68 2.806
12 2.41E-05
0 0.00E+00
0%
Pass
69 2.831
11 2.21E-05
0 0.00E+00
0%
Pass
70 2.856
9 1.81E-05
0 0.00E+00
0%
Pass
11/15/2022 PH1 Page 930 of 1307

71 2.881
9 1.81E-05
0 0.00E+00
0%
Pass
72 2.905
9 1.81E-05
0 0.00E+00
0%
Pass
73 2.930
9 1.81E-05
0 0.00E+00
0%
Pass
74 2.955
9 1.81E-05
0 0.00E+00
0%
Pass
75 2.980
9 1.81E-05
0 0.00E+00
0%
Pass
76 3.005
9 1.81E-05
0 0.00E+00
0%
Pass
77 3.030
8 1.61E-05
0 0.00E+00
0%
Pass
78 3.055
8 1.61E-05
0 0.00E+00
0%
Pass
79 3.080
8 1.61E-05
0 0.00E+00
0%
Pass
80 3.105
7 1.41E-05
0 0.00E+00
0%
Pass
81 3.130
7 1.41E-05
0 0.00E+00
0%
Pass
82 3.155
7 1.41E-05
0 0.00E+00
0%
Pass
83 3.179
6 1.21E-05
0 0.00E+00
0%
Pass
84 3.204
6 1.21E-05
0 0.00E+00
0%
Pass
85 3.229
6 1.21E-05
0 0.00E+00
0%
Pass
86 3.254
6 1.21E-05
0 0.00E+00
0%
Pass
87 3.279
6 1.21E-05
0 0.00E+00
0%
Pass
88 3.304
6 1.21E-05
0 0.00E+00
0%
Pass
89 3.329
6 1.21E-05
0 0.00E+00
0%
Pass
90 3.354
6 1.21E-05
0 0.00E+00
0%
Pass
91 3.379
6 1.21E-05
0 0.00E+00
0%
Pass
92 3.404
6 1.21E-05
0 0.00E+00
0%
Pass
93 3.429
6 1.21E-05
0 0.00E+00
0%
Pass
94 3.453
6 1.21E-05
0 0.00E+00
0%
Pass
95 3.478
6 1.21E-05
0 0.00E+00
0%
Pass
96 3.503
6 1.21E-05
0 0.00E+00
0%
Pass
97 3.528
6 1.21E-05
0 0.00E+00
0%
Pass
98 3.553
6 1.21E-05
0 0.00E+00
0%
Pass
99 3.578
5 1.01E-05
0 0.00E+00
0%
Pass
100
j 3.603
j 5
j 1.01E-05
j 0
j 0.00E+00
j 0%
j Pass
11/15/2022 PH1 Page 931 of 1307

Peak flows calculated with the Weibull Plotting Position Return Period
(years)
Pre-Dev. Peak
Flows (cfs)
Post-Dev.

Peak Flows(cfs)
Reduction
(cfs)
LF = 0.1xQ2

1.112

0.474

0.638
2-year

2.224

0.948

1.276
3-year

2.398

1.032

1.366
4-year

2.744

1.166

1.578
5-year

2.825

1.208

1.617
6-year

2.896

1.247

1.648
7-year

3.063

1.315

1.748
8-year

3.138

1.349

1.789
9-year

3.369

1.427

1.942
10-year

3.603

1.513

2.090
11 /15/2022 PH 1 Page 932 of 1307

ATTACHMENT 3
List of the "n" largest Peaks: Pre -Development and Post -Development Conditions
11/15/2022 PH1 Page 933 of 1307

List of the "n" Largest Peaks: Pre & Post -Developed Conditions • Basic Probabilistic Equation: R = P
where,
R = Return period in years; and
P = Probability of a flow to be equaled or exceeded any given year (dimensionless). • Weibull Equation: P = i n
where,
i = Position of the peak whose probability is desired (sorted from large to small); and n = number of years analyzed.

Explanation of Variables for the Tables in this Attachment • Peak: Refers to the peak flow at the date given, taken from the continuous simulation hourly results of the n year analyzed.
• Posit: If all peaks are sorted from large to small, the position of the peak in a sorting analysis is included under the variable Posit.
• Date: Date of the occurrence of the peak at the outlet form the continuous simulation. • Note: All peaks are not annual maxima; instead they are defined as event maxima, with a threshold to separate peaks of at least 12 hours. In other words, any peak P in a time series is defined as a value where dP/dt=0, and the peak is the largest value in 25 hours (12 hours before the hour of occurrence and 12 hours after the occurrence, so it is in essence a daily peak).
11 /15/2022 PH 1 Page 934 of 1307

Pre -Project Flow Frequency for POC-1- Long-term Simulation Camino Largo, Vista, CA, Pre -Developed Runoff Condition, POC-1 Statistics - Node POC-1 Total Inflow
Rank
Start Date
Event
Duration
(hours)
Event
Peak
(CFS)
Exceedance
Frequency
(percent)
Return
Period
(years)
1 4/14/2003
8 5.563

0.28 58
2 1/4/1978
3 5.189

0.55 29
3 10/1/1983
3 4.985

0.83 19.33
4 1/15/1979
4 4.679

1.11 14.5
5 1/4/1995
7 4.509

1.39 11.6
6 9/23/1986
1 4.195

1.66 9.67
7 2/25/2003
6 3.763

1.94 8.29
8 2/3/1958
31 3.67

2.22 7.25
9 2/24/1969
45 3.6

2.49 6.44
10 10/27/2004
8 3.376

2.77 5.8
11 1/13/1993
10 3.358

3.05 5.27
12 10/29/2000
2 3.339

3.32 4.83
13 2/18/2005
19 3.325

3.6 4.46
14 2/20/1980
13 3.284

3.88 4.14
15 3/ 17/ 1982
17 3.241

4.16 3.87
16 1/16/1952
8 3.226

4.43 3.63
17 2/28/1978
16 3.199

4.71 3.41
18 4/1/1958
9 3.184

4.99 3.22
19 3/2/1980
14 2.87

5.26 3.05
20 2/ 10/ 1978
4 2.802

5.54 2.9
21 12/29/1991
13 2.793

5.82 2.76
22 11/22/1965
25 2.79

6.09 2.64
23 2/27/1983
4 2.779

6.37 2.52
24 1/29/1983
4 2.777

6.65 2.42
25 2/3/1998
7 2.776

6.93 2.32
26 12/19/1970
20 2.725

7.2 2.23
27 1/27/2008
21 2.698

7.48 2.15
28 2/22/1998
34 2.646

7.76 2.07
29 2/16/1980
3 2.635

8.03 2
30 10/20/2004
6 2.527

8.31 1.93
31 11/15/1952
2 2.526

8.59 1.87
32 2/16/1998
31 2.495

8.86 1.81
33 11/11/1985
5 2.495

9.14 1.76
34 2/ 18/ 1993
1 2.474

9.42 1.71
35 12/ 1/ 1961
19 2.473

9.7 1.66
36 2/3/1994
12 2.384

9.97 1.61
11/15/2022 PH1 Page 935 of 1307

37 1/15/1993
76 2.349

10.25 1.57
38 1/16/1978
9 2.31

10.53 1.53
39 3/11/1995
23 2.249

10.8 1.49
40 1/5/2008
45 2.244

11.08 1.45
41 2/14/1986
7 2.225

11.36 1.41
42 1/28/1980
26 2.217

11.63 1.38
43 2/14/1998
9 2.193

11.91 1.35
44 3/ 17/ 1963
3 2.177

12.19 1.32
45 3/15/1986
22 2.136

12.47 1.29
46 2/12/1992
15 2.103

12.74 1.26
47 2/22/2008
8 2.066

13.02 1.23
48 1/ 16/ 1972
3 2.058

13.3 1.21
49 2/27/1991
41 2.049

13.57 1.18
50 3/19/1981
2 2.036

13.85 1.16
51 4/27/1960
4 2.027

14.13 1.14
52 12/ 22/ 1982
1 1.999

14.4 1.12
53 2/8/1993
10 1.977

14.68 1.09
54 2/11/2003
27 1.937

14.96 1.07
55 2/6/1969
9 1.878

15.24 1.05
56 8/ 17/ 1977
2 1.873

15.51 1.04
57 1/11/2005
9 1.842

15.79 1.02
58 4/28/2005
1 1.832

16.07 1
Pre -project
10-year Q: cfs
5-year Q:121
cfs
2-year Q:cfs
Lower Flow Threshold 50%

0.1xQ2 (Pre): 1.318 cfs
11/15/2022 PH1 Page 936 of 1307

Pre -Project Flow Frequency for POC-2 - Long-term Simulation Camino Largo, Vista, CA, Pre -Developed Runoff Condition, POC 2 Statistics - Node POC-2 Total Inflow
Rank
Start Date
Event
Duration
(hours)
Event
Peak
(CFS)
Exceedance
Frequency
(percent)
Return
Period
(years)
1 4/14/2003
8 4.668

0.27 58
2 1/4/1978
3 4.361

0.55 29
3 10/1/1983
3 4.183

0.82 19.33
4 1/15/1979
4 3.925

1.1 14.5
5 1/4/1995
6 3.782

1.37 11.6
6 9/23/1986
1 3.566

1.64 9.67
7 2/25/2003
6 3.16

1.92 8.29
8 2/3/1958
31 3.081

2.19 7.25
9 2/24/1969
45 3.022

2.47 6.44
10 10/27/2004
7 2.838

2.74 5.8
11 1/13/1993
10 2.834

3.01 5.27
12 10/29/2000
2 2.82

3.29 4.83
13 2/18/2005
19 2.794

3.56 4.46
14 2/20/1980
13 2.757

3.84 4.14
15 3/17/1982
17 2.731

4.11 3.87
16 1/16/1952
8 2.71

4.38 3.63
17 2/28/1978
16 2.688

4.66 3.41
18 4/1/1958
9 2.68

4.93 3.22
19 3/2/1980
14 2.421

5.21 3.05
20 2/10/1978
4 2.352

5.48 2.9
21 12/29/1991
13 2.347

5.75 2.76
22 11/22/1965
25 2.346

6.03 2.64
23 2/27/1983
4 2.344

6.3 2.52
24 1/29/1983
4 2.343

6.58 2.42
25 2/3/1998
7 2.333

6.85 2.32
26 12/19/1970
20 2.298

7.12 2.23
27 1/27/2008
21 2.289

7.4 2.15
28 2/16/1980
3 2.236

7.67 2.07
29 2/22/1998
34 2.224

7.95 2
30 11/15/1952
2 2.15

8.22 1.93
31 10/20/2004
6 2.148

8.49 1.87
32 11/11/1985
5 2.133

8.77 1.81
33 2/18/1993
1 2.126

9.04 1.76
34 2/16/1998
31 2.097

9.32 1.71
35 12/1/1961
20 2.088

9.59 1.66
36 2/3/1994
12 2.031

9.86 1.61
11/15/2022 PH1 Page 937 of 1307

37 1/15/1993
76 2.002

10.14 1.57
38 1/16/1978
9 1.939

10.41 1.53
39 3/11/1995
23 1.92

10.68 1.49
40 1/5/2008
45 1.894

10.96 1.45
41 2/14/1986
7 1.875

11.23 1.41
42 1/28/1980
26 1.86

11.51 1.38
43 3/17/1963
3 1.848

11.78 1.35
44 2/14/1998
9 1.845

12.05 1.32
45 3/15/1986
22 1.809

12.33 1.29
46 2/12/1992
15 1.795

12.6 1.26
47 2/27/1991
41 1.753

12.88 1.23
48 2/22/2008
8 1.737

13.15 1.21
49 12/22/1982
1 1.732

13.42 1.18
50 1/ 16/ 1972
3 1.731

13.7 1.16
51 3/19/1981
2 1.727

13.97 1.14
52 4/27/1960
4 1.704

14.25 1.12
53 2/8/1993
10 1.677

14.52 1.09
54 2/11/2003
27 1.632

14.79 1.07
55 4/28/2005
1 1.622

15.07 1.05
56 2/6/1969
9 1.616

15.34 1.04
57 8/17/1977
2 1.574

15.62 1.02
58 1/11/2005
9 1.548

15.89 1
Pre -project
10-year Q: 3.603 cfs
5-year Q: 2.825 cfs
2-year Q: 2.224 cfs
Lower Flow Threshold 50%

0.1xQ2 (Pre): 1.112 cfs
11/15/2022 PH1 Page 938 of 1307

Post -Project (Mitigated) Flow Frequency for POC-1- Long-term Simulation Camino Largo, Vista, CA Post -Developed Mitigated Runoff Condition - POC-1 Statistics - Node POC-1 Total Inflow
Rank
Start Date
Event
Duration
(hours)
Event
Peak
(CFS)
Exceedance
Frequency
(percent)
Return
Period
(years)
1 4/14/2003
38 5.217

0.11 58
2 9/29/1983
50 4.79

0.22 29
3 1/3/1995
45 4.515

0.34 19.33
4 1/14/1979
33 4.504

0.45 14.5
5 1/3/1978
74 3.443

0.56 11.6
6 2/25/2003
68 3.169

0.67 9.67
7 9/23/1986
35 3.168

0.78 8.29
8 10/27/2004
34 3.138

0.9 7.25
9 2/23/1969
55 3.117

1.01 6.44
10 2/27/1978
142

3.021

1.12 5.8
11 2/3/1958
38 2.967

1.23 5.27
12 2/ 13/ 1980
190

2.881

1.35 4.83
13 1/16/1952
53 2.857

1.46 4.46
14 2/5/1978
209

2.721

1.57 4.14
15 3/2/1980
22 2.672

1.68 3.87
16 2/18/2005
33 2.558

1.79 3.63
17 3/17/1982
45 2.502

1.91 3.41
18 1/16/1978
14 2.354

2.02 3.22
19 1/27/1980
67 2.337

2.13 3.05
20 11/22/1965
29 2.277

2.24 2.9
21 8/16/1977
30 2.226

2.35 2.76
22 2/20/2008
54 2.21

2.47 2.64
23 2/3/1998
40 2.203

2.58 2.52
24 1/16/1972
15 2.193

2.69 2.42
25 10/29/2000
28 2.183

2.8 2.32
26 12/16/1970
75 2.114

2.91 2.23
27 12/29/1991
15 2.032

3.03 2.15
28 1/12/1993
151

2.005

3.14 2.07
29 2/22/1998
69 1.973

3.25 2
30 3/31/1958
107

1.88 3.36

1.93 31
2/ 14/ 1986
14 1.877

3.48 1.87
32 1/5/1979
33 1.849

3.59 1.81
33 1/14/1978
19 1.848

3.7 1.76
34 3/7/1968
18 1.811

3.81 1.71
35 1/20/1962
59 1.792

3.92 1.66
36 4/27/1960
11 1.775

4.04 1.61
11 /15/2022 PH 1 Page 939 of 1307

37 2/ 16/ 1998
43 1.716

4.15 1.57
38 1/7/2005
119

1.702

4.26 1.53
39 11/11/1985
29 1.693

4.37 1.49
40 12/28/2004
53 1.692

4.48 1.45
41 11/17/1986
18 1.686

4.6 1.41
42 11/14/1952
45 1.676

4.71 1.38
43 3/24/1994
25 1.651

4.82 1.35
44 3/16/1963
24 1.649

4.93 1.32
45 2/26/1983
165

1.478

5.04 1.29
46 3/11/1995
27 1.46

5.16 1.26
47 12/24/1988
9 1.451

5.27 1.23
48 2/26/2004
13 1.426

5.38 1.21
49 2/1/1960
11 1.412

5.49 1.18
50 12/3/1966
93 1.408

5.61 1.16
51 12/18/1967
44 1.39

5.72 1.14
52 1/12/1960
10 1.387

5.83 1.12
53 1/3/2005
55 1.38

5.94 1.09
54 1/28/1983
15 1.35

6.05 1.07
55 9/17/1963
44 1.342

6.17 1.05
56 1/13/1957
12 1.332

6.28 1.04
57 1/5/2008
54 1.28

6.39 1.02
58 11/21/1996
18 1.243

6.5 1
Post -project (Mitigated)
10-year Q: 3.216 cfs
5-year Q: 2.914 cfs
2-year Q: 1.973 cfs
Lower Flow Threshold 50%

0.1xQ2 (Pre): 0.987 cfs
11 /15/2022 PH 1 Page 940 of 1307

Post -Protect (Mitigated) Flow Frequency for POC-2 - Long-term Simulation Camino Largo, Vista, CA Post -Developed Mitigated Runoff Condition - POC 2 Statistics - Node POC-1 Total Inflow
Rank
Start Date
Event
Duration
(hours)
Event
Peak
(CFS)
Exceedance
Frequency
(percent)
Return
Period
(years)
1 4/14/2003
5 1.912

0.3 58
2 1/4/1978
3 1.852

0.61 29
3 10/1/1983
2 1.714

0.91 19.33
4 1/15/1979
4 1.693

1.22 14.5
5 1/4/1995
6 1.618

1.52 11.6
6 9/23/1986
1 1.491

1.83 9.67
7 2/25/2003
4 1.359

2.13 8.29
8 2/3/1958
30 1.322

2.44 7.25
9 2/24/1969
44 1.299

2.74 6.44
10 1/13/1993
9 1.224

3.05 5.8
11 10/27/2004
7 1.219

3.35 5.27
12 2/18/2005
3 1.201

3.66 4.83
13 2/20/1980
12 1.188

3.96 4.46
14 10/29/2000
2 1.166

4.27 4.14
15 1/16/1952
7 1.166

4.57 3.87
16 2/28/1978
14 1.162

4.88 3.63
17 4/1/1958
6 1.154

5.18 3.41
18 3/17/1982
17 1.123

5.49 3.22
19 3/2/1980
14 1.037

5.79 3.05
20 2/10/1978
4 1.023

6.1 2.9
21 2/27/1983
1 1.017

6.4 2.76
22 1/29/1983
4 1.015

6.71 2.64
23 11/22/1965
20 1.013

7.01 2.52
24 2/3/1998
4 1.008

7.32 2.42
25 1/27/2008
20 1

7.62 2.32
26 2/16/1980
3 0.98

7.93 2.23
27 12/29/1991
10 0.964

8.23 2.15
28 2/22/1998
28 0.963

8.54 2.07
29 12/19/1970
1 0.948

8.84 2
30 2/16/1998
26 0.91

9.15 1.93
31 2/18/1993
1 0.906

9.45 1.87
32 11/ 15/ 1952
1 0.901

9.76 1.81
33 11/11/1985
3 0.901

10.06 1.76
34 10/20/2004
6 0.898

10.37 1.71
35 1/18/1993
6 0.885

10.67 1.66
36 12/2/1961
14 0.863

10.98 1.61
11 /15/2022 PH 1 Page 941 of 1307

37 1/28/1980
27 0.862

11.28 1.57
38 3/11/1995
22 0.852

11.59 1.53
39 2/3/1994
12 0.851

11.89 1.49
40 3/ 15/ 1986
23 0.848

12.2 1.45
41 1/16/1978
5 0.847

12.5 1.41
42 1/5/2008
43 0.83

12.8 1.38
43 2/14/1986
7 0.818

13.11 1.35
44 2/14/1998
4 0.803

13.41 1.32
45 2/12/1992
14 0.797

13.72 1.29
46 2/27/1991
41 0.781

14.02 1.26
47 3/17/1963
3 0.771

14.33 1.23
48 2/22/2008
7 0.765

14.63 1.21
49 1/16/1972
2 0.765

14.94 1.18
50 12/22/1982
1 0.749

15.24 1.16
51 2/8/1993
10 0.743

15.55 1.14
52 2/6/1969
7 0.731

15.85 1.12
53 4/28/2005
1 0.727

16.16 1.09
54 3/ 19/ 1981
1 0.72

16.46 1.07
55 4/27/1960
2 0.7

16.77 1.05
56 12/31/2004
2 0.69

17.07 1.04
57 1/11/2005
7 0.682

17.38 1.02
58 3/1/1983
65 0.676

17.68 1
Post-proiect (Mitigated)
10-year Q: 1.513 cfs
5-year Q: 1.208 cfs
2-year Q: 0.948 cfs
Lower Flow Threshold 50%

0.1xQ2 (Pre): 0.474 cfs
11 /15/2022 PH 1 Page 942 of 1307

ATTACHMENT 4
Elevation vs. Area Curves and Elevation vs. Discharge Curves to be used in SWMM
11 /15/2022 PH 1 Page 943 of 1307

Elevation vs. Area
The elevation vs. area curves in the model are calculated in Excel and imported into the model. The summary of elevation vs. area for each BMP has been provided on the following pages.

The LID surface storage depth beneath the lowest surface discharge structure is accounted for in the LID module as illustrated in Attachment 7.

Elevation vs. Discharge
The total elevation vs. discharge curve is imported from an Excel spreadsheet that calculates the elevation vs. discharge of the outlet system. Elevation vs. discharge relationships are provided in the surface discharge of the biofiltration basin as this is where a Modified Puls routing procedure will be applied in the continuous simulation model.

The low -flow orifice size has been selected to maximum its size while still restricting flows to conform with the required 50% of the Qz event flow as mandated in the Final Hydromodification Management Plan by Brown & Caldwell, dated March 2011. While BHA acknowledges that this orifice is small, to increase the size of these outlets would impact the basin's ability to restrict flows beneath the HMP thresholds, thus preventing the BMP from conforming with HMP requirements.

In order to further reduce the risk of blockage of the orifice, regular maintenance of the riser and orifice must be performed to ensure potential blockages are minimized. A detail of the orifice and riser structures are provided in Attachment 5 of this memorandum. 11 /15/2022 PH 1 Page 944 of 1307

Discharge Equations
The following equations are based on the San Diego County Hydraulic Design Manual (September 2014):
• Weir:

QW=Cw*L*H3/2
• Slot:

As an orifice: Qs = Bs * hs * cg * 2g(H — ZS)
Asa weir: QS = CW * BS * H3/2
(1)
(2.a)
(2.b)
For H > hs slot works as weir until orifice equation provides a smaller discharge. The elevation such that equation (2.a) = equation (2.b) is the elevation at which the behavior changes from weir to orifice.

Vertical Orifices:

As an orifice: Qo = 0.25 * 7TD2 * cg * 2g(H - D)
(3.a)
Asa weir: Critical depth and geometric family of circular sector must be solved to determine Q as a function of H:

Eo — —cr . H = Ycr + Acr ; Tcr = 2 Ycr(D — Ycr); Acr — DZ [acr — sin(acr)]; 9 Tcr 2 *Tcr 8
Ycr = D [1 — sin(0.5 * acr)] (3.b.1, 3.b.2, 3.b.3, 3.b.4 and 3.b.5) There is a value of H (approximately H=110%D) from which orifices no longer work as weirs as critical depth is not possible at the entrance of the orifice. This value of H is obtained equaling the discharge using critical equations and equations (3.b).

A mathematical model is prepared with the previous equations depending on the type of discharge.

The following are the variables used above:

Qw, Q, Qo : Discharge of weir, slot or orifice (cfs)
Cw, cg: Coefficients of discharge of weir (typically 3.1) and orifice (0.61 to 0.62) L, BS, D, hs: Length of weir, width of slot, diameter of orifice and height of slot, respectively; (ft) H: Level of water in the pond over the invert of slot, weir or orifice (ft) Acr, Tcr. Ycr. acr: Critical variables for circular sector: area (sq-ft), top width (ft), critical depth (ft), and angle to the center, respectively.
11 /15/2022 PH 1 Page 945 of 1307

Stage -Area for Basin 1
Elevation vs. Area Tables
Depth (ft)
Area (ft 2)
Volume (ft)

0.000
6147
0 0.083
6173
514

0.167
6199
1033

0.250
6225
1556

0.333
6250
2083

0.417
6276
2615

0.500
6302
3151

0.583
6328
3691

0.667
6354
4236

0.750
6380
4785

0.833
6405
5338

0.917
6431
5895

1.000
6457
6457

1.083
6483
7023

1.167
6509
7593

1.250
6535
8168

1.333
6560
8747

1.417
6586
9330

1.500
6612
9918

1.583
6638
10510

1.667
6664
11106

1.750
6690
11707

1.833
6715
12311

1.917
6741
12921

2.000
6767
13534
SUB SURFACE STORAGE BASIN 1
Elevation (ft)
Area (ft)
Volume (ft)
-1.50
6147
1844
-2.08
6147
1434
Gravel &Amended Soil TOTAL=
Surface Total TOTAL=
BMP TOTAL=
3278
4236
7514
Amended Soil Base (0.2voids)
Gravel Base (0.4voids)
(ft 3)
(ft)
(ft)
(1):The area at this surface elevation corresponds to the area of gravel and amended soil (biofiltration layer) (2): Volumeat this elevation cores ponds with surface volume for WQ purposes (invert of lowest surface outlet) 11 /15/2022 PH 1 Page 946 of 1307

Outlet Structure for Discharge of Basin 1
Elevation vs. Discharge Table
Outlet Structure for Discharge of BMP 1
Discharge vs. Elevation Table
Lower orifice
No. of orif:

Dia:

I nvert:

Area:

Cg-I ow:

Middle orifice
No. of orif:

Dia:

I nvert:

Area:

Cg-I ow:
0 3 in

0.000 ft

0.049 sf

0.62 0
4in

0.417 ft

0.000 sf

0.62 Lower Slot
No. of slots;
Invert:

B (width):

Area:
hsiot (height)
Cg-I ow:

Upper slot
No. of slots:

Invert:

B (width):

Area:
hsiot(height)
Cg-I ow:
1 0.000 ft

2.833 ft

1.181 sf

0.417 ft

0.62 1

0.583 ft

0.833 ft

0.275 sf

0.330 ft

0.62 *Note: h = head above the invert of the lowest surface discharge opening.

USE
Emergency Weir
I nvert:

V-Notch Angle

1.250 ft

20.000 ft
0 Basin Elev.
(ft)
H
(ft)
h*
(ft)
Qorifice-low
(cfs)
Qorifice-upper
(cfs)
Qslot-low
(cfs)
Qslot-upper
(cfs)
Qemerg
(cfs)
Qtot
(cfs)
308.900

0.500

0.000

0.000
308.983

0.583

0.083

0.000

1.193

0.000

1.193
309.067

0.667

0.167

0.000

1.687

0.278

0.000

1.965
309.150

0.750

0.250

0.000

2.066

0.393

0.000

2.459
309.233

0.833

0.333

0.000

2.077

0.481

0.000

2.558
309.317

0.917

0.417

0.000

2.681

0.556

0.000

3.237
309.400

1.000

0.500

0.000

3.172

0.686

0.000

3.859
309.483

1.083

0.583

0.000

3.597

0.792

0.000

4.389
309.567

1.167

0.667

0.000

3.977

0.885

0.000

4.862
309.650

1.250

0.750

0.000

4.323

0.969

0.000

5.292
309.733

1.333

0.833

0.000

4.644

1.047

0.000

5.690
309.817

1.417

0.917

0.000

4.944

1.119

0.000

6.062
309.900

1.500

1.000

0.000

5.226

1.186

0.000

6.413
309.983
1 1.583

1.083

0.000

5.494

1.250

0.000

6.745
310.067

1.667

1.167

0.000

5.750

1.311

0.000

7.061
310.150

1.750

1.250

0.000

5.995

1.369

0.000

7.364
310.233

1.833

1.333

0.000

6.230

1.425

1.491

9.147
310.317

1.917

1.417

0.000

6.457

1.479

4.219

12.154
310.400

2.000

1.500

0.000

6.676

1.531

7.750

15.956
310.483

2.083

1.583

0.000

6.888

1.581

11.932

20.400
310.567

2.167

1.667

0.000

7.093

1.630

16.675

25.398
310.650

2.250

1.750

0.000

7.293

1.677

21.920

30.890
11/15/2022 PH Page 947 of 1307

Camino Largo
BMP 1
Bio-Retention Cell LID
PARAMETER ABBREV. BMP
Ponding Depth PD 6 in
Bioretention Soil Layer S 18 in
Gravel Layer G 7 in
TOTAL
Orifice Coefficient
Low Flow Orifice Diameter
Drain exponent
Flow Rate (volumetric)
Ponding Depth Surface Area
Bioretention Surface Area
Porosity of Bioretention Soil
Flow Rate (per unit area)
Effective Ponding Depth
Flow Coefficient

2.58 ft
31 in
Cg 0.6 --
D 4.00 in
n 0.5 --
9 APD
As, AG
As, AG
rl
q
P Deff
C
Ponding Depth @ VWQ required PDorificeFL
Cutoff Flow Qcutoff

0.653
ft3/s
6225
ft2
6147
ft2

0.141
ac

0.40 --

11.477
in/hr

6.04 in

0.8596 --
6 in

0.65321 cfs
11 /15/2022 PH 1 Page 948 of 1307

Stage -Area for Basin 2
Elevation vs. Area Tables
Depth (ft)
Area (ft2)
Volume (ft)

0.000
9279
0 0.083
9318
783

0.167
9358
1586

0.250
9397
2408

0.333
9436
3250

0.417
9475
4112

0.500
9515
4993

0.583
9554
5894

0.667
9593
6814

0.750
9632
7754

0.833
9672
8714

0.917
9711
9693

1.000
9750
10692

1.083
9789
11711

1.167
9829
12749

1.250
9868
13807

1.333
9907
14884

1.417
9946
15981

1.500
9986
17098

1.583
10025
18234

1.667
10064
19390

1.750
10103
20566

1.833
10143
21761

1.917
10182
22976

2.000
10221
24210
11 /15/2022 PH 1 Page 949 of 1307

SUBSURFACE STORAGE BASIN 2
Elevation (ft)
Area (ft')
Volume (ft)
-1.50
9279
2784
-2.50
9279
3712
Gravel &Amended Soil
Surface Total
BMP
TOTAL=
TOTAL=
TOTAL=
6495
6814
13309
Amended Soil Base (0.2voids)
Gravel Base (0.4voids)
(ft)
(ft)
(ft)
(1):The area at this surface elevation corresponds to the area of gravel and amended soil (biofiltration layer) (2):Vol umeat this elevation cores ponds with surface volume for WQpurposes (invert of Iowestsurface outlet) Effective Depth: 6.08 in
11 /15/2022 PH 1 Page 950 of 1307

Outlet Structure for Discharge of Basin 2
Elevation vs. Discharge Table
Outlet Structure for Discharge of BMP 2
Discharge vs. Elevation Table
Lower orifice
No. of orif:

Di a:

I nvert:

Area:

Cg-I ow:

Middle orifice
No. of orif:

Di a:

I nvert:

Area:

Cg-I ow:
0 3 in

0.000 ft

0.049 sf

0.62 0
4in

0.417 ft

0.000 sf

0.62 Lower Slot
No. of slots:

Invert:

B (width):

Area:
h,lot(height):

Cg-I ow:

Uoaer slot
No. of slots:

Invert:

B (width):

Area:
hslot (height):

Cg-I ow:
1 0.000 ft

2.670 ft

0.668 sf

0.250 ft

0.62 1

0.583 ft

0.500 ft

0.083 sf

0.167 ft

0.62 *Note: h = head above the invert of the lowest surface discharge opening.

USE
Emergency Weir
I nvert:

V-Notch Angle

1.000 ft

11.830 ft
0 Basin Elev.
(ft)
H
(ft)
h*
(ft)
Qorifice-low
(cfs)
Qorifice-upper
(cfs)
Qslot-low
(cfs)
Qslot-upper
(cfs)
Qemerg
(cfs)
Qtot
(cfs)
308.900

0.500

0.000

0.000
308.983

0.583

0.083

0.000

0.674

0.000

0.674
309.067

0.667

0.167

0.000

0.954

0.084

0.000

1.038
309.150

0.750

0.250

0.000

1.168

0.119

0.000

1.287
309.233

0.833

0.333

0.000

1.516

0.204

0.000

1.720
309.317

0.917

0.417

0.000

1.794

0.207

0.000

2.001
309.400

1.000

0.500

0.000

2.034

0.239

0.000

2.273
309.483

1.083

0.583

0.000

2.248

0.268

0.000

2.516
309.567

1.167

0.667

0.000

2.444

0.293

0.000

2.737
309.650

1.250

0.750

0.000

2.626

0.317

0.000

2.942
309.733

1.333

0.833

0.000

2.795

0.339

0.000

3.134
309.817

1.417

0.917

0.000

2.955

0.359

0.000

3.314
309.900

1.500

1.000

0.000

0.000
1 3.107

0.378

0.000

3.485
309.983

1.583

1.083

0.000

3.251

0.397

0.882

4.530
310.067

1.667

1.167

0.000

3.390

0.415

2.495

6.300
310.150

1.750

1.250

0.000

3.523

0.432

4.584

8.538
310.233

1.833

1.333

0.000

3.651

0.448

7.058

11.156
310.317

1.917

1.417

0.000

3.775

0.464

9.863

14.102
310.400

2.000

1.500

0.000

3.894

0.479

12.966

17.339
310.483

2.083

1.583

0.000

4.011

0.494

16.339

20.843
310.567

2.167

1.667

0.000

4.124

0.508

19.962

24.594
310.650

2.250

1.750

0.000

4.234

0.522

23.820

28.575
11 /15/2022 PH 1 Page 951 of 1307

Camino Largo
BMP2
Bio-Retention Cell LID
PARAMETER ABBREV. BMP
Ponding Depth PD 6 in
Bioretention Soil Layer S 18 in
Gravel Layer G 7 in
TOTAL
Orifice Coefficient
Low Flow Orifice Diameter
Drain exponent
Flow Rate (volumetric)
Ponding Depth Surface Area
Bioretention Surface Area
Porosity of Bioretention Soil
Flow Rate (per unit area)
Effective Ponding Depth
Flow Coefficient

2.5833333 ft
31 in
Cg 0.6 --
D 3.00 in
n 0.5 --
0 APD
As, AG
As, AG
n
q
P Deff
C
Ponding Depth @ VWQ, required PDorificeFL
Cutoff Flow Qcutoff

0.371
ft3/s
9515
ft2
9279
ft2

0.213
ac

0.40 --

4.313
in/hr

6.08 in

0.3203 --
6 in

0.37058 cfs
11 /15/2022 PH 1 Page 952 of 1307

ATTACHMENT 5
Basin Outlet Details
11 /15/2022 PH 1 Page 953 of 1307

f
B
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a
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§
2 \_
)
In�
§
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;2
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X 2 4
?SSSGSSS73®
22 )\
k2
�$
§z
�§
11/15 2022 PIMq Page 954 of1307

\
�
ul
§
§}
2 /
/
&
\§
§ 2
§
z
§
gA3SS9A232v
11/15 2022 PIHq Page 955 of1307

MALE NATIONAL PIPE THREAD

PVC ADAPTER CAST

IN SIDE OF RISER WALL---,
• a

UNDERDRAIN ORIFICE

THREADED FEMALE NATIONAL

PIPE THREAD PVC CAP
WITH DRILLED ORIFICE _
F.14 I"a"Alll
6' I FROVCH DRAW,
} PERFORA7ED PVC PIPE
@OTTOfII OF BASBW
6' PERFORA 70 PVC PIPE

UNDERDRAIN ORIFICE

THREADED FEMALE NATIONAL
PIPE THREAD PVC CAP z n
WITH DRILLED ORIFICE °
RESTRICTCR CAP DETAIL BMP 1 & 2

NOT TO SCALE
_ OUTLET STRUCTURE
r `�
UPPER
INVERT

LOWER SLOT
INVERT

PONDING DEPV

BASIN BOTTOM
RISER
INVERT
_EV

UPPER SLOT OPENING IN

RISER STRUCTURE
P

LOWER SLOT OPENING IN

RISER STRUCTURE
CUTLET STRUCTURE DETAIL BMP 1 & 2

NOT TO SCALE
11 /15/2022 PH 1 Page 956 of 1307

ATTACHMENT 6
SWMM Input Data in Input Format
(Existing and Proposed Models)
11 /15/2022 PH 1 Page 957 of 1307

POC-1

PRE -DEVELOPED RUNOFF CONDITION INPUT FILE
[TITLE]
;;Project Title/Notes
Camino Largo, Vista, CA, Pre -Developed Runoff Condition, POC-1 [OPTIONS]
;;Option
Value
FLOW_UNITS
CFS

INFILTRATION
GREEN_AMPT
FLOW_ROUTING

KINWAVE

LINK OFFSETS
DEPTH
MIN_SLOPE
0 ALLOW_PONDING
NO

SKIP STEADY STATE
NO
START_DATE
08/28/1951
START_TIME
05:00:00

REPORT START DATE
08/28/1951

REPORT START TIME
05:00:00
END
05/23/2008
—DATE

END TIME
23:00:00

SWEEP START
01/01

SWEEP END
12/31

DRY DAYS
0 REPORT STEP
01:00:00
WET
00:15:00
—STEP

DRY STEP
04:00:00

ROUTING STEP
0:01:00
INERTIAL_DAMPING

PARTIAL

NORMAL FLOW LIMITED
BOTH

FORCE MAIN EQUATION
H-W

VARIABLE STEP

0.75 LENGTHENING_STEP
0 MIN_SURFAREA
0 MAX TRIALS
0 HEAD TOLERANCE
0 SYS FLOW TOL
5 LAT FLOW TOL
5 MINIMUM STEP

0.5 THREADS
1 11/15/2022 P441 Page 958 of 1307

[EVAPORATION]
;;Data Source Parameters
..-------------- ----------------
MONTHLY 0.03 0.05 0.08 0.11 0.13 0.15 0.15 0.13 0.11 0.08 0.04 0.02

DRY ONLY NO
[RAINGAGES]
;;Name Format Interval SCF Source
..----------------------- ------ ----------------
OCEANSIDE INTENSITY 1:00 1.0 TIMESERIES OCEANSIDE
[SUBCATCHMENTS]
;;Name Rain Gage Outlet Area %Impery Width %Slope CurbLen SnowPack ..-------------------------------------------------------------------------------------- ---------------- DMA-1 OCEANSIDE POC-1 4.952 0 890 7.10 0
[SUBAREAS]
;;Subcatchment N-Impery N-Pery S-Impery S-Pery PctZero RouteTo PctRouted DMA-1 0.012 0.10 0.05 0.1 25 OUTLET
[INFILTRATION]
;;Subcatchment Suction Ksat IMD
..--------------------------------------------
DMA-1 9 0.025 0.30
[OUTFALLS]
;;Name Elevation Type Stage Data Gated Route To
..---------------------------------------------------------- ---------------- POC-1 0 FREE NO
[TIMESERIES]
;;Name Date Time Value
..--------------------------------------------
OCEANSIDE FILE "K:\Library\Stormwater\SWMM\RAIN GAGES\Oceanside Rain Data.dat" [REPORT]
;;Reporting Options

INPUT NO

CONTROLS NO

SUBCATCHMENTS ALL

NODES ALL

LINKS ALL
11 /15/2022 PH 1 Page 959 of 1307

[TAGS]
[MAP]
DIMENSIONS 191.920 4920.830 1021.827 5718.627
Units None
[COORDINATES]
;;Node X-Coord Y-Coord
..-------------------------------- ------------------
POC-1 757.069 4959.747
[VERTICES]
;;Link X-Coord Y-Coord
..--------------------------------------------------
[Polygons]
;;Subcatchment X-Coord Y-Coord
..-------------------------------- ------------------
DMA-1 706.040 5124.523
[SYMBOLS]
;;Gage X-Coord Y-Coord
..-------------------------------- ------------------
OCEANSIDE 757.548 5779.526
11 /15/2022 PH 1 Page 960 of 1307

POC-1

POST -DEVELOPED RUNOFF CONDITION INPUT FILE
[TITLE]
;;Project Title/Notes
Camino Largo, Vista, CA Post -Developed Mitigated Runoff Condition - POC-1 [OPTIONS]
;;Option
Value

FLOW UNITS
CFS

INFILTRATION
GREEN_AMPT

FLOW ROUTING

KINWAVE

LINK OFFSETS
DEPTH

MIN SLOPE
0 ALLOW_PONDING
NO

SKIP STEADY STATE
NO
START_DATE
08/28/1951
START_TIME
05:00:00

REPORT START DATE
08/28/1951

REPORT START TIME
05:00:00

END DATE
05/23/2008

END TIME
23:00:00

SWEEP START
01/01

SWEEP END
12/31

DRY DAYS
0 REPORT STEP
01:00:00
WET
00:15:00
—STEP

DRY STEP
04:00:00

ROUTING STEP
0:01:00
INERTIAL_DAMPING

PARTIAL

NORMAL FLOW LIMITED
BOTH

FORCE MAIN EQUATION
H-W

VARIABLE STEP

0.75 LENGTHENING_STEP
0 MIN_SURFAREA
0 MAX TRIALS
0 HEAD TOLERANCE
0 SYS FLOW TOL
5 LAT FLOW TOL
5 MINIMUM STEP

0.5 THREADS
1 11 /15/2022 PH 1 Page 961 of 1307

[EVAPORATION]
;;Data Source Parameters
MONTHLY 0.03 0.05 0.08 0.11 0.13 0.15 0.15 0.13 0.11 0.08 0.04 0.02

DRY ONLY NO
[RAINGAGES]
;;Name Format Interval SCF Source
OCEANSIDE INTENSITY 1:00 1.0 TIMESERIES OCEANSIDE
[SUBCATCHMENTS]
;;Name Rain Gage Outlet Area %Impery Width %Slope CurbLen SnowPack ..-------------------------------------------------------------------------------------- ---------------- DMA-1 OCEANSIDE BMP-1 4.706 58.42 993 8.30 0
BMP-1 OCEANSIDE DIV-1 0.141 0 30 0 0
[SUBAREAS]
;;Subcatchment N-Impery N-Pery S-Impery S-Pery PctZero RouteTo PctRouted ..------------------------------------------------------------------------------------ DMA-1 0.012 0.10 0.05 0.10 25 OUTLET
BMP-1 0.012 0.10 0.05 0.10 25 OUTLET
[INFILTRATION]
;;Subcatchment
..--------------
Suction
----------
Ksat
----------
IMD
----------
DMA-1
9 0.01875

0.3 BMP-1
9 0.025

0.3 [LID_CONTROLS]
;;Name
..--------------
Type/Layer
----------
Parameters
----------
BMP--
BC
BMP-1

SURFACE

6.04 0.0
0 0
BMP-1
SOIL
18 0.4

0.2 0.1
BMP-1

STORAGE
7 0.67
0 0
BMP-1
DRAIN

0.8596

0.5 3
6 5
5 5 1.5
[LID USAGE]
;;Subcatchment LID Process Number Area Width InitSat FromImp ToPery RptFile DrainTo
-- ----------------
BMP-- BMP-1 1 6141.96 0 0 100 0
11 /15/2022 PH 1 Page 962 of 1307

[OUTFALLS]
;;Name Elevation Type Stage Data Gated Route To
POC-1 0 FREE NO
[DIVIDERS]
;;Name Elevation Diverted Link Type Parameters
DIV-1 0 BYPASS-1 CUTOFF 0.65321 0 0 0 0
[STORAGE]
;;Name Elev. MaxDepth InitDepth Shape Curve Name/Params N/A Fevap Psi Ksat IMD
..------------------------------------------------------------------------------------------------- --- STOR-1 0 1.50 0 TABULAR STORAGE-lB 0 0
[CONDUITS]
;;Name From Node To Node Length Roughness InOffset OutOffset InitFlow MaxFlow ..---------------------------------------------------------------------------------------------------------- BYPASS-1 DIV-1 STOR-1 10 0.01 0 0 0 0
DUM 1 DIV-1 POC-1 10 0.01 0 0 0 0
[OUTLETS]
;;Name From Node To Node Offset Type QTable/Qcoeff Qexpon Gated ..--------------------------------------------------------------------------------------------------------- STOR-I-ORIFICE STOR-1 POC-1 0 TABULAR/DEPTH STOR-1BORIFICE NO [XSECTIONS]
;;Link Shape Geoml Geom2 Geom3 Geom4 Barrels Culvert
..-------------------------------------------------------------------------------------------- BYPASS-1 DUMMY 0 0 0 0 1
DUM 1 DUMMY 0 0 0 0 1
[CURVES]
;;Name Type
..------------------------
X-Value
----------
Y-Value
----------
STOR-1BORIFICE Rating

0.000

0.000
STOR-1BORIFICE

0.083

1.193
STOR-1BORIFICE

0.167

1.965
STOR-1BORIFICE

0.250

2.459
STOR-1BORIFICE

0.333

2.558
STOR-1BORIFICE

0.417

3.237
STOR-1BORIFICE

0.500

3.859
STOR-1BORIFICE

0.583

4.389
11 /15/2022 PH 1 Page 963 of 1307

STOR-1BORIFICE

0.667

4.862
STOR-1BORIFICE

0.750

5.292
STOR-1BORIFICE

0.833

5.690
STOR-1BORIFICE

0.917

6.062
STOR-1BORIFICE

1.000

6.413
STOR-1BORIFICE

1.083

6.745
STOR-1BORIFICE

1.167

7.061
STOR-1BORIFICE

1.250

7.364
STOR-1BORIFICE

1.333

9.147
STOR-1BORIFICE

1.417

12.154
STOR-1BORIFICE

1.500

15.956
STOR-1BORIFICE

1.583

20.400
STOR-1BORIFICE

1.667

25.398
STOR-1BORIFICE

1.750

30.890
STORAGE-1B
Storage 0.00
6302
STORAGE-1B

0.08 6328
STORAGE-1B

0.17 6354
STORAGE-1B

0.25 6380
STORAGE-lB

0.33 6405
STORAGE-1B

0.42 6431
STORAGE-lB

0.50 6457
STORAGE-lB

0.58 6483
STORAGE-1B

0.67 6509
STORAGE-lB

0.75 6535
STORAGE-1B

0.83 6560
STORAGE-lB

0.92 6586
STORAGE-1B

1.00 6612
STORAGE-1B

1.08 6638
STORAGE-1B

1.17 6664
STORAGE-1B

1.25 6690
STORAGE-1B

1.33 6715
STORAGE-1B

1.42 6741
STORAGE-1B

1.50 6767
[TIMESERIES]
;;Name
..--------------
Date Time
Value

OCEANSIDE
--------------------
FILE "K:\Library\Stormwater\SWMM\RAIN
----------
GAGES\Oceanside Rain Data.dat"
[REPORT]
;;Reporting Options

INPUT NO

CONTROLS NO

SUBCATCHMENTS ALL
11 /15/2022 PH 1 Page 964 of 1307

NODES ALL

LINKS ALL
[TAGS]
[MAP]
DIMENSIONS 191.920 4920.830 1021.827 5718.627
Units None
[COORDINATES]
;;Node
..--------------
X-Coord
Y-Coord
POC-1
------------------
717.654
------------------
5272.826
DIV-1
413.901
5274.612
STOR-1
416.581
5123.629
[VERTICES]
;;Link X-Coord Y-Coord
..--------------------------------------------------
[Polygons]
;;Subcatchment X-Coord Y-Coord
..-------------------------------- ------------------
DMA-1 159.285 5271.932
BMP-1 277.213 5270.145
[SYMBOLS]
;;Gage X-Coord Y-Coord
..-------------------------------- ------------------
OCEANSIDE 546.123 5415.768
11 /15/2022 PH 1 Page 965 of 1307

POC-2

PRE -DEVELOPED RUNOFF CONDITION INPUT FILE
[TITLE]
;;Project Title/Notes
Camino Largo, Vista, CA, Pre -Developed Runoff Condition, POC 2 [OPTIONS]
;;Option
Value

FLOW UNITS
CFS

INFILTRATION
GREEN_AMPT

FLOW ROUTING

KINWAVE

LINK OFFSETS
DEPTH
MIN_SLOPE
0 ALLOW_PONDING
NO

SKIP STEADY STATE
NO
START_DATE
08/28/1951
START_TIME
05:00:00

REPORT START DATE
08/28/1951

REPORT START TIME
05:00:00

END DATE
05/23/2008

END TIME
23:00:00

SWEEP START
01/01

SWEEP END
12/31

DRY DAYS
0 REPORT STEP
01:00:00
WET —STEP
00:15:00

DRY STEP
04:00:00

ROUTING STEP
0:01:00
INERTIAL_DAMPING

PARTIAL

NORMAL FLOW LIMITED
BOTH

FORCE MAIN EQUATION
H-W

VARIABLE STEP

0.75 LENGTHENING STEP
0 11 /15/2022 PH 1 Page 966 of 1307

MIN_SURFAREA
0 MAX TRIALS
0 HEAD TOLERANCE
0 SYS_FLOW _TOL
5 LAT FLOW TOL
5 MINIMUM STEP

0.5 THREADS
1 [EVAPORATION]
;;Data Source Parameters
..-------------- ----------------
MONTHLY 0.03 0.05 0.08 0.11 0.13 0.15 0.15 0.13 0.11 0.08 0.04 0.02

DRY ONLY NO
[RAINGAGES]
;;Name Format Interval SCF Source
..----------------------- ------ ----------------
OCEANSIDE INTENSITY 1:00 1.0 TIMESERIES OCEANSIDE
[SUBCATCHMENTS]
;;Name Rain Gage Outlet Area %Impery Width %Slope CurbLen SnowPack ..-------------------------------------------------------------------------------------- ---------------- DMA-1 OCEANSIDE POC-1 3.121 0 507 10.10 0
BYPASS2 OCEANSIDE POC-1 1.031 0 785 11.2 0
[SUBAREAS]
;;Subcatchment N-Impery N-Pery S-Impery S-Pery PctZero RouteTo PctRouted ..------------------------------------------------------------------------------------ DMA-1 0.012 0.10 0.05 0.1 25 OUTLET
BYPASS2 0.012 0.10 0.05 0.10 25 OUTLET
[INFILTRATION]
;;Subcatchment Suction Ksat IMD
..--------------------------------------------
DMA-1 9 0.025 0.30
BYPASS2 9 0.025 0.30
[OUTFALLS]
;;Name Elevation Type Stage Data Gated Route To
..---------------------------------------------------------- ---------------- POC-1 0 FREE NO
[TIMESERIES]
;;Name Date Time Value
..--------------------------------------------
11 /15/2022 PH 1 Page 967 of 1307

OCEANSIDE FILE "K:\Library\Stormwater\SWMM\RAIN GAGES\Oceanside Rain Data.dat" [REPORT]
;;Reporting Options

INPUT NO

CONTROLS NO

SUBCATCHMENTS ALL

NODES ALL

LINKS ALL
[TAGS]
[MAP]
DIMENSIONS 191.920 4920.830 1021.827 5718.627
Units None
[COORDINATES]
;;Node X-Coord Y-Coord
..-------------------------------- ------------------
POC-1 757.069 4959.747
[VERTICES]
;;Link X-Coord Y-Coord
..-------------------------------- ------------------
[Polygons]
;;Subcatchment X-Coord Y-Coord
..-------------------------------- ------------------
DMA-1 706.040 5124.523
BYPASS2 804.759 5127.873
[SYMBOLS]
;;Gage X-Coord Y-Coord
..-------------------------------- ------------------
OCEANSIDE 757.548 5779.526
11 /15/2022 PH 1 Page 968 of 1307

POC-2

POST -DEVELOPED RUNOFF CONDITION INPUT FILE
[TITLE]
;;Project Title/Notes
Camino Largo, Vista, CA Post -Developed Mitigated Runoff Condition - POC 2 [OPTIONS]
;;Option
Value

FLOW UNITS
CFS

INFILTRATION
GREEN_AMPT

FLOW ROUTING

KINWAVE

LINK OFFSETS
DEPTH
MIN_SLOPE
0 ALLOW_PONDING
NO

SKIP STEADY STATE
NO
START_DATE
08/28/1951
START_TIME
05:00:00

REPORT START DATE
08/28/1951

REPORT START TIME
05:00:00

END DATE
05/23/2008

END TIME
23:00:00

SWEEP START
01/01

SWEEP END
12/31

DRY DAYS
0 REPORT STEP
01:00:00
WET —STEP
00:15:00

DRY STEP
04:00:00

ROUTING STEP
0:01:00
INERTIAL_DAMPING

PARTIAL

NORMAL FLOW LIMITED
BOTH

FORCE MAIN EQUATION
H-W

VARIABLE STEP

0.75 LENGTHENING STEP
0 11 /15/2022 PH 1 Page 969 of 1307

MIN_SURFAREA
0 MAX TRIALS
0 HEAD TOLERANCE
0 SYS_FLOW _TOL
5 LAT FLOW TOL
5 MINIMUM STEP

0.5 THREADS
1 [EVAPORATION]
;;Data Source Parameters
..-------------- ----------------
MONTHLY 0.03 0.05 0.08 0.11 0.13 0.15 0.15 0.13 0.11 0.08 0.04 0.02

DRY ONLY NO
[RAINGAGES]
;;Name
..--------------
Format
---------
Interval SCF
------ ----------------
Source

OCEANSIDE

INTENSITY
1:00 1.0

TIMESERIES

OCEANSIDE
[SUBCATCHMENTS]
;;Name
..--------------
Rain Gage
----------------
Outlet
----------------
Area
--------
%Impery
--------
Width
--------
%Slope
--------
CurbLen SnowPack
-------- ----------------
DMA-2

OCEANSIDE
BMP-2

3.146

57.73 818

4.50 0
BMP-2

OCEANSIDE
DIV-2

0.213
0 20
0 0
BYPASS2

OCEANSIDE
POC-1

1.699
0 785

11.20 0
[SUBAREAS]
;;Subcatchment
..--------------
N-Impery
----------
N-Pery
----------
S-Impery
----------
S-Pery
----------
PctZero
----------
RouteTo PctRouted
--------------------
DMA-2

0.012

0.10 0.05

0.10 25
OUTLET
BMP-2

0.012

0.10 0.05

0.10 25
OUTLET
BYPASS2

0.012

0.10 0.05

0.10 25
OUTLET
[INFILTRATION]
;;Subcatchment
..--------------
Suction
----------
Ksat
----------
IMD
----------
DMA-2
9 0.01875

0.3 BMP-2
9 0.025

0.3 BYPASS2
9 0.025

0.3 [LID CONTROLS]
;;Name
..--------------
Type/Layer
----------
Parameters
----------
BMP-2
BC
BMP-2

SURFACE

6.08 0.0 0.1 0 5
11/15/2022 PH1 Page 970 of 1307

BMP-2 SOIL 18 0.4 0.2 0.1 5 5 1.5
BMP-2 STORAGE 7 0.67 0 0
BMP-2 DRAIN 0.3203 0.5 3 6
[LID USAGE]
;;Subcatchment LID Process Number Area Width InitSat FromImp ToPery RptFile DrainTo
-- ----------------
BMP-2 BMP-2 1 8319.96 0 0 100 0
[OUTFALLS]
;;Name Elevation Type Stage Data Gated Route To
..---------------------------------------------------------- ---------------- POC-1 0 FREE NO
[DIVIDERS]
;;Name Elevation Diverted Link Type Parameters
..------------------------------------------------------------ DIV-2 0 BYPASS-2 CUTOFF 0.37058 0 0 0 0
[STORAGE]
;;Name Elev. MaxDepth InitDepth Shape Curve Name/Params N/A Fevap Psi Ksat IMD
..------------------------------------------------------------------------------------------------- --- STOR-2 0 1.50 0 TABULAR STORAGE-1B 0 0
[CONDUITS]
;;Name
..--------------
From Node
----------------
To Node
----------------
Length
----------
Roughness InOffset OutOffset
------------------------------
InitFlow
----------
MaxFlow
----------
BYPASS-2
DIV-2
STOR-2
10 0.01 0
0 0
0 DUM 2
DIV-2
POC-1
10 0.01 0
0 0
0 [OUTLETS]
;;Name
..--------------
From Node
To Node
Offset
Type
QTable/Qcoeff
Qexpon
Gated
STOR-2-ORIFICE
----------------
STOR-2
----------------
POC-1
----------
0 ---------------

TABULAR/DEPTH
----------------
STOR-1BORIFICE
----------
--------
NO
[XSECTIONS]
;;Link
..--------------
Shape
------------
Geoml
----------------
Geom2
----------
Geom3 Geom4
--------------------
Barrels Culvert
--------------------
BYPASS-2
DUMMY
0 0
0 0
1 DUM 2
DUMMY
0 0
0 0
1 11/15/2022 PH1 Page 971 of 1307

[CURVES]
;;Name
Type
X-Value
Y-Value
STOR-1BORIFICE
Rating

0.000

0.000
STOR-1BORIFICE

0.083

0.674
STOR-1BORIFICE

0.167

1.038
STOR-1BORIFICE

0.250

1.287
STOR-1BORIFICE

0.333

1.720
STOR-1BORIFICE

0.417

2.001
STOR-1BORIFICE

0.500

2.273
STOR-1BORIFICE

0.583

2.516
STOR-1BORIFICE

0.667

2.737
STOR-1BORIFICE

0.750

2.942
STOR-1BORIFICE

0.833

3.134
STOR-1BORIFICE

0.917

3.314
STOR-1BORIFICE

1.000

3.485
STOR-1BORIFICE

1.083

4.530
STOR-1BORIFICE

1.167

6.300
STOR-1BORIFICE

1.250

8.538
STOR-1BORIFICE

1.333

11.156
STOR-1BORIFICE

1.417

14.102
STOR-1BORIFICE

1.500

17.339
STOR-1BORIFICE

1.583

20.843
STOR-1BORIFICE

1.667

24.594
STOR-1BORIFICE

1.750

28.575
STORAGE-lB
Storage

0.00 9515
STORAGE-lB

0.08 9554
STORAGE-1B

0.17 9593
STORAGE-lB

0.25 9632
STORAGE-1B

0.33 9672
STORAGE-lB

0.42 9711
STORAGE-lB

0.50 9750
STORAGE-1B

0.58 9789
STORAGE-lB

0.67 9829
STORAGE-1B

0.75 9868
STORAGE-lB

0.83 9907
STORAGE-1B

0.92 9946
STORAGE-lB

1.00 9986
STORAGE-1B

1.08 10025
STORAGE-lB

1.17 10064
STORAGE-1B

1.25 10103
STORAGE-lB

1.33 10143
STORAGE-1B

1.42 10182
STORAGE-lB

1.50 10221
11 /15/2022 PH 1 Page 972 of 1307

[TIMESERIES]
;;Name Date Time Value
..--------------------------------------------
OCEANSIDE FILE "K:\Library\Stormwater\SWMM\RAIN GAGES\Oceanside Rain Data.dat" [REPORT]
;;Reporting Options

INPUT NO

CONTROLS NO

SUBCATCHMENTS ALL

NODES ALL

LINKS ALL
[TAGS]
[MAP]
DIMENSIONS 191.920 4920.830 1021.827 5718.627
Units None
[COORDINATES]
;;Node
..--------------
X-Coord
------------------
Y-Coord
------------------
POC-1
717.654
5272.826
DIV-2
413.901
5272.826
STOR-2
419.262
5124.523
[VERTICES]
;;Link X-Coord Y-Coord
..--------------------------------------------------
[Polygons]
;;Subcatchment
..--------------
X-Coord
------------------
Y-Coord
------------------
DMA-2
159.285
5271.932
BMP-2
278.999
5270.145
BYPASS2
722.121
5432.742
[SYMBOLS]
;;Gage
..--------------
X-Coord
------------------
Y-Coord
------------------

OCEANSIDE
546.123
5415.768
11/15/2022 PH1 Page 973 of 1307

11 /15/2022 PH 1 Page 974 of 1307

ATTACHMENT 7
SWMM Screens and Explanation of Significant Variables
11 /15/2022 P(H1 Page 975 of 1307

EPA SWMM Figures and Explanations
Per the attached, the reader can see the screens associated with the EPA-SWMM Model in both pre - development and post -development conditions. Each portion, i.e., sub -catchments, storage units, weirs and orifices as a discharge, and outfalls (point of compliance), are also shown.

Variables for modeling are associated with typical recommended values by the EPA-SWMM model and the Model BMP Design Manual San Diego Region.

Soil characteristics of the existing soils were determined from the site specific NRCS Web Soil Survey.

Some values incorporated within the SWMM model have been determined from the professional experience of BHA using conservative assumptions that have a tendency to increase the size of the needed BMP and also generate a long-term runoff as a percentage of rainfall similar to those measured in gage stations in Southern California by the USGS.
11/15/2022 PH1 Page 976 of 1307

PRE -DEVELOPED CONDITION (POC-1)
11 /15/2022 PH 1 Page 977 of 1307

POST -DEVELOPED CONDITION (POC-1)
DMA-1 BMP-1
■--------------------- ■---•-------------------

BYPASS-
STOR-1
wir

OCEANSIDE
El
1UL• I
11/15/2022 PH Page 978 of 1307

PRE -DEVELOPED CONDITION (POC-2)
DMA-1 BYPASS2
POD-1
i
11/15/2022 PH1 Page 979 of 1307

POST -DEVELOPED CONDITION (POC-2)
DMA-2 BMP-2
-

BYPASS-
DIV-2
STAR-2
lit-

OCEANSIDE
0 num
B Y PAS S2
POC-1
11/15/2022 Ptd1 Page 980 of 1307

Explanation of Selected Variables
• Sub Catchment Areas: Please refer to the attached diagram that indicates the DMA and biofiltration BMP sub -areas modeled within the project site at both the pre and post - developed conditions draining to the project's POCs.

Parameters for the pre -developed model include soils Type C and D as determined from the NRCS Web Soils Survey and ArcGIS BMP Sizing Calculator (see Attachment 8). For the purpose of this report, the entire project site will be modeled with Type D soils. Suction head, conductivity and initial deficit correspond to average values expected for this soil type, according to the BMP Design Manual (BMPDM).
• Selection of a Kinematic Approach: As the continuous model is based on hourly rainfall, and the time of concentration for the pre -development and post -development conditions is significantly smaller than 60 minutes, precise routing of the flows through the impervious surfaces, the underdrain pipe system, and the discharge pipe was considered unnecessary.

The truncation error of the precipitation into hourly steps is much more significant that the precious routing in a system where the time of concentration is much smaller than 1 hour. • Sub Catchment BMP: The subcatchment BMP is assigned the area of biofiltration, which is equal to the area of amended soil. At least five (5) decimal places were given regarding the area of the biofiltration to insure that the area used by the program for the LID subroutine corresponds exactly with the actual biofiltration area.

LID Control Editor: Explanation of Significant Variables • Storage Depth: The storage depth variable within the SWMM model is representative of the storage volume provided beneath the lowest surface outlet within the biofiltration basin.

This is the volume that can only discharge from the facility via the LID portion of the basin.

In those cases where the surface storage has a variable area that is also different to the area of the gravel and amended soil, the SWMM model needs to be calibrated as the LID module will use the storage depth multiplied by the BMP area as the amount of volume stored at the surface.

Let ABMP be the area of the BMP (area of amended soil and area of gravel). The proper value of the storage depth SD to be included in the LID module can be calculated by using geometric properties of the surface volume. Let Ao be the surface area at the bottom of the surface 11 /15/2022 PH 1 Page 981 of 1307

pond, and let A; be the surface area at the elevation of the invert of the first row of orifices (or at the invert of the riser if not surface orifices are included). Finally, let h; be the difference in elevation between Ao and A;. By volumetric definition:

ABMP * SD — (AO Ai) hi
(1)
Equation (1) allows the determination of SD to be included as Storage Depth in the LID module.
• Porosity: A porosity value of 0.4 has been selected for the model. The amended soil is to be highly sandy in content in order to have a saturated hydraulic conductivity of approximately 5 in/hr.

BHA considers such a value to be slightly high; however, in order to comply with the BMPDM, the value recommended by the Copermittees for the porosity of amended soil is 0.4, per Appendix G of the BMPDM. Such porosity is equal to the porosity of the gravel per the same manual.
• Porosity: The ratio of the void volume divided by the soil volume is directly related to porosity.

Note, by definition, Porosity = Void Ratio _ (1 + Void Ratio). As the underdrain layer is composed of gravel, a porosity value of 0.4 has been selected (also per Appendix G of the BMPDM), which results in a void ratio of 0.4/(1+0.4) = 0.67 for the gravel detention layer. • Conductivity: Due to the preliminary nature of this study, infiltration may not be a viable addition to the LID design. Even when soil types C and D are present, which generally have low infiltration rates, the possibility that a very low infiltration rate could be determined at design level must be considered. The range of potential infiltration rates to be studied when a site -specific geotechnical investigation has not been completed is shown in Table G.1-5 of the BMP Design Manual. Based on the infiltration rates shown, a conservative low infiltration rate of 0 inches per hour was selected for soil Type D. Therefore, as the BMPs are designed without infiltration, the conductivity value was set to 0 to represent zero infiltration. • Clogging factor: A clogging factor was not used (0 indicates that there is not clogging assumed within the model). The reason for this is related to the fairness of a comparison with the SDHM model and the HMP sizing tables: a clogging factor was not considered. • Drain (Flow) coefficient: The flow coefficient in the SWMM Model is the coefficient needed to transform the orifice equation into a general power law equation of the form:
11 /15/2022 PH 1 Page 982 of 1307

q = C(H — HD)n
where,
q is the peak flow in in/hr;
(2)
n is exponent (typically 0.5 for orifice equation);
Ho is the elevation of the centroid of the orifice in inches (assumed equal to the invert of the orifice for small orifices and in our design equal to 0); and H is the depth of the water in inches.

The general orifice equation can be expressed as:
_ Tr DZT2g
(H—HD) (3)
Q 4 C9 144 12
where,
Q is the peak flow in cfs;
D is the underdrain orifice diameter in inches;
cg is the typical discharge coefficient for orifices (0.60-0.65 for thin walls and 0.75-0.80 for thick walls);
g is the gravitational constant (32.2 ft/S2); and
H and Ho are defined above are also used in inches in Equation (3).

It is clear that:
_ (in ABMP _
q hr 12*3600 — Q(CfS)
H
The flow coefficient used in the SWMM Model characterizes the rate of discharge to the outlet as a function of the height of water stored in the biofiltration cell. The flow coefficient, as presented in the BMPDM, can be determined by the following equation:
605 7rD2 g
C=C —
9 Alid ( 8 ) 6
where,
(5)
cg is the orifice discharge coefficient (0.60-0.65 for thin walls and 0.75-0.80 for thick walls);
Ai;d is the cumulative footprint area (ft2) of all LID controls; D is the underdrain orifice diameter in inches; and
g is the gravitational constant (32.2 ft/S2);
11 /15/2022 PH 1 Page 983 of 1307

• Cut -Off Flow: The cut-off flow represents the maximum flow rate leaving the "low flow" outlet. The low -flow restrictor is typically more restrictive (i.e. smaller flow rate) than the percolation rate through the engineered soil; therefore, the orifice equation is used to calculate the cutoff flow when H is maximum.
11 /15/2022 PH 1 Page 984 of 1307

ATTACHMENT 8
Geotechnical Documentation
(See Attachment 5 in SWQMP)
11 /15/2022 PH 1 Page 985 of 1307

ATTACHMENT 9
Summary Files from the SWMM Model
11 /15/2022 PH 1 Page 986 of 1307

PRE -DEVELOPED RUNOFF CONDITION (POC-1) OUTPUT FILE
EPA STORM WATER MANAGEMENT MODEL - VERSION 5.1 (Build 5.1.012) -------------------------------------------------------------- Camino Largo, Vista, CA, Pre -Developed Runoff Condition, POC-1 ********************************************************* NOTE: The summary statistics displayed in this report are based on results found at every computational time step, not just on results from each reporting time step.
********************************************************* ****************
Analysis Options
****************
Flow Units ...............

CFS
Process Models:

Rainfall/Runoff ........

YES
RDII ...................

NO
Snowmelt ...............

NO
Groundwater ............

NO
Flow Routing ...........

NO
Water Quality ..........

NO
Infiltration Method ......

GREEN_AMPT
Starting Date ............
08/28/1951 05:00:00
Ending Date ..............
05/23/2008 23:00:00
Antecedent Dry Days ......

0.0 Report Time Step .........
01:00:00
Wet Time Step ............
00:15:00
Dry Time Step ............
04:00:00
**************************
Volume
Depth
Runoff Quantity Continuity
**************************
acre-feet
---------
inches
-------
Total Precipitation ......
278.595
675.110
Evaporation Loss .........

6.647

16.107
Infiltration Loss ........
213.620
517.658
Surface Runoff ...........

62.281
150.923
Final Storage ............

0.000

0.000
Continuity Error (o) .....
-1.419
11 /15/2022 PH 1 Page 987 of 1307

**************************
Volume
Volume
Flow Routing Continuity
**************************
acre-feet
10^6 gal
Dry Weather Inflow .......
---------

0.000
---------

0.000
Wet Weather Inflow .......

62.281

20.295
Groundwater Inflow .......

0.000

0.000
RDII Inflow ..............

0.000

0.000
External Inflow ..........

0.000

0.000
External Outflow .........

62.281

20.295
Flooding Loss ............

0.000

0.000
Evaporation Loss .........

0.000

0.000
Exfiltration Loss ........

0.000

0.000
Initial Stored Volume ....

0.000

0.000
Final Stored Volume ......

0.000

0.000
Continuity Error (o) .....

0.000
***************************
Subcatchment Runoff Summary
***************************
-------------------------------------------------------------------------------------------------------- Total
Total
Total
Total
Total
Total
Peak Runoff
Precip
Runon
Evap
Infil
Runoff
Runoff
Runoff Coeff
Subcatchment in
in
in
in
in
10^6 gal
CFS
-------------------------------------------------------------------------------------------------------- DMA-1 675.11

0.00 16.11
517.66
150.92

20.29 5.56 0.224
Analysis begun on: Sat Aug 14 14:13:46 2021
Analysis ended on: Sat Aug 14 14:14:22 2021
Total elapsed time: 00:00:36
11 /15/2022 PH 1 Page 988 of 1307

POST -DEVELOPED RUNOFF CONDITION (POC-1) OUTPUT FILE
EPA STORM WATER MANAGEMENT MODEL - VERSION 5.1 (Build 5.1.012) -------------------------------------------------------------- Camino Largo, Vista, CA Post -Developed Mitigated Runoff Condition - POC-1 WARNING 04: minimum elevation drop used for Conduit BYPASS-1 WARNING 04: minimum elevation drop used for Conduit DUM 1 ********************************************************* NOTE: The summary statistics displayed in this report are based on results found at every computational time step, not just on results from each reporting time step.
********************************************************* Analysis Options
Flow Units ...............

Process Models:

Rainfall/Runoff ........

RDII ...................

Snowmelt ...............

Groundwater ............

Flow Routing ...........

Ponding Allowed ........

Water Quality ..........

Infiltration Method ......

Flow Routing Method ......

Starting Date ............

Ending Date ..............

Antecedent Dry Days ......

Report Time Step .........

Wet Time Step ............

Dry Time Step ............

Routing Time Step ........
**************************
CFS
YES
NO
NO
NO
YES
NO
NO
GREEN_AMPT

KINWAVE
08/28/1951 05:00:00
05/23/2008 23:00:00

0.0 01:00:00
00:15:00
04:00:00

60.00 sec
Volume Depth
11 /15/2022 PH 1 Page 989 of 1307

Runoff Quantity Continuity
**************************
acre-feet
inches
Initial LID Storage ......
---------

0.021
-------

0.052
Total Precipitation ......
272.688
675.110
Evaporation Loss .........

30.080

74.470
Infiltration Loss ........

77.561
192.022
Surface Runoff ...........

13.864

34.325
LID Drainage .............
154.588
382.722
Final Storage ............

0.040

0.100
Continuity Error (%) .....
-1.255
**************************
Volume
Volume
Flow Routing Continuity
**************************
acre-feet
---------
10^6 gal
---------
Dry Weather Inflow .......

0.000

0.000
Wet Weather Inflow .......
168.453

54.893
Groundwater Inflow .......

0.000

0.000
RDII Inflow ..............

0.000

0.000
External Inflow ..........

0.000

0.000
External Outflow .........
168.461

54.895
Flooding Loss ............

0.000

0.000
Evaporation Loss .........

0.000

0.000
Exfiltration Loss ........

0.000

0.000
Initial Stored Volume ....

0.000

0.000
Final Stored Volume ......

0.000

0.000
Continuity Error (%) .....
-0.005
********************************
Highest Flow Instability Indexes
********************************
All links are stable.
*************************
Routing Time Step Summary
*************************
Minimum
Time Step

60.00 sec
Average
Time Step

60.00 sec
Maximum
Time Step

60.00 sec
Percent
in Steady State

0.00 Average
Iterations per Step

1.00 Percent
Not Converging

0.00 11 /15/2022 PH 1 Page 990 of 1307

***************************
Subcatchment Runoff Summary
***************************
-------------------------------------------------------------------------------------------------------- Total
Total
Total
Total
Total
Total
Peak
Runoff
Precip
Runon
Evap
Infil
Runoff
Runoff
Runoff
Coeff
Subcatchment in
in
in
in
in
10^6 gal
CFS
-------------------------------------------------------------------------------------------------------- DMA-1 675.11

0.00 53.04
197.78
433.01

55.33 5.55

0.641
BMP-1 675.11
14452.06
789.58

0.00 14336.36

54.89 5.72

0.948
LID Performance Summary
***********************
-------------------------------------------------------------------------------------------------------------------- Total
Evap
Infil
Surface
Drain
Initial
Final Continuity
Inflow
Loss
Loss
Outflow
Outflow
Storage
Storage Error
Subcatchment LID Control in
in
in
in
in
in
in o
-------------------------------------------------------------------------------------------------------------------- BMP-1 BMP-1 15127.17
789.61

0.00 1179.99
13156.89

1.80 2.61 -0.00
******************
Node Depth Summary
--------------------------------------------------------------------------------- Average
Maximum
Maximum
Time of Max
Reported
Depth
Depth
HGL
Occurrence
Max Depth
Node
Type
Feet
Feet
Feet
days hr:min
Feet
--------------------------------------------------------------------------------- POC-1

OUTFALL

0.00 0.00

0.00 0 00:00

0.00 DIV-1

DIVIDER

0.00 0.00

0.00 0 00:00

0.00 STOR-1

STORAGE

0.00 0.66

0.66 18857 12:17

0.61 *******************
Node Inflow Summary
*******************
------------------------------------------------------------------------------------------------- Maximum Maximum Lateral Total Flow
11/15/2022 PH1 Page 991 of 1307

Lateral
Total
Time of Max
Inflow
Inflow
Balance
Inflow
Inflow
Occurrence
Volume
Volume
Error
Node
Type
CFS
CFS
days hr:min
10^6 gal
10^6 gal
Percent
------------------------------------------------------------------------------------------------- POC-1

OUTFALL

0.00 5.47
18857 12:17
0 54.9

0.000
DIV-1

DIVIDER

5.72 5.72
18857 12:01

54.9 54.9

0.000
STOR-1

STORAGE

0.00 5.07
18857 12:01
0 4.17
-0.060
*********************
Node Flooding Summary
*********************
No nodes were flooded.
**********************
Storage Volume Summary
**********************
-------------------------------------------------------------------------------------------------- Average
Avg
Evap
Exfil
Maximum
Max
Time of Max
Maximum
Volume
Pcnt
Pcnt
Pcnt
Volume
Pcnt
Occurrence
Outflow
Storage Unit 1000 ft3
Full
Loss
Loss
1000 ft3
Full
days hr:min
CFS
-------------------------------------------------------------------------------------------------- STOR-1 0.001
0 0
0 4.226
43 18857 12:16

4.82 Outfall Loading Summary
***********************
----------------------------------------------------------- Flow
Avg
Max
Total
Freq
Flow
Flow
Volume
Outfall Node Pcnt
CFS
CFS
10^6 gal
----------------------------------------------------------- POC-1 2.11

0.19 5.47

54.891
----------------------------------------------------------- System 2.11

0.19 5.47

54.891
Link Flow Summary
11 /15/2022 PH 1 Page 992 of 1307

----------------------------------------------------------------------------- Maximum
Time of Max
Maximum
Max/
Max/
IFlowl
Occurrence
IVelocl
Full
Full
Link Type CFS
----------------------------------------------------------------------------- days hr:min
ft/sec
Flow
Depth
BYPASS-1 DUMMY
DUM_1 DUMMY

STOR-I-ORIFICE DUMMY
*************************
Conduit Surcharge Summary
*************************
No conduits were surcharged.

5.07 18857 12:01

0.65 141 06:38

4.82 18857 12:17
Analysis begun on: Fri Dec 03 13:51:33 2021
Analysis ended on: Fri Dec 03 13:52:29 2021
Total elapsed time: 00:00:56
11 /15/2022 PH 1 Page 993 of 1307

PRE -DEVELOPED RUNOFF CONDITION (POC-2) OUTPUT FILE
[TITLE]
;;Project Title/Notes
Camino Largo, Vista, CA, Pre -Developed Runoff Condition, POC 2 [OPTIONS]
;;Option
Value
FLOW_UNITS
CFS

INFILTRATION
GREEN_AMPT
FLOW_ROUTING

KINWAVE

LINK OFFSETS
DEPTH
MIN_SLOPE
0 ALLOW_PONDING
NO

SKIP STEADY STATE
NO
START_DATE
08/28/1951
START_TIME
05:00:00

REPORT START DATE
08/28/1951

REPORT START TIME
05:00:00
END
05/23/2008
—DATE
END_TIME
23:00:00

SWEEP START
01/01

SWEEP END
12/31

DRY DAYS
0 REPORT STEP
01:00:00
WET
00:15:00
—STEP

DRY STEP
04:00:00

ROUTING STEP
0:01:00
INERTIAL_DAMPING

PARTIAL

NORMAL FLOW LIMITED
BOTH

FORCE MAIN EQUATION
H-W
VARIABLE_STEP

0.75 LENGTHENING_STEP
0 MIN_SURFAREA
0 MAX TRIALS
0 HEAD TOLERANCE
0 SYS_FLOW _TOL
5 LAT FLOW TOL
5 MINIMUM STEP

0.5 THREADS
1 [EVAPORATION]
;;Data Source Parameters
11 /15/2022 P841 Page 994 of 1307

MONTHLY 0.03 0.05 0.08 0.11 0.13 0.15 0.15 0.13 0.11 0.08 0.04 0.02

DRY ONLY NO
[RAINGAGES]
;;Name Format Interval SCF Source
..----------------------- ------ ----------------
OCEANSIDE INTENSITY 1:00 1.0 TIMESERIES OCEANSIDE
[SUBCATCHMENTS]
;;Name Rain Gage Outlet Area %Impery Width %Slope CurbLen SnowPack ..-------------------------------------------------------------------------------------- ---------------- DMA-1 OCEANSIDE POC-1 3.121 0 507 10.10 0
BYPASS2 OCEANSIDE POC-1 1.031 0 785 11.2 0
[SUBAREAS]
;;Subcatchment N-Impery N-Pery S-Impery S-Pery PctZero RouteTo PctRouted ..------------------------------------------------------------------------------------ DMA-1 0.012 0.10 0.05 0.1 25 OUTLET
BYPASS2 0.012 0.10 0.05 0.10 25 OUTLET
[INFILTRATION]
;;Subcatchment Suction Ksat IMD
..--------------------------------------------
DMA-1 9 0.025 0.30
BYPASS2 9 0.025 0.30
[OUTFALLS]
;;Name Elevation Type Stage Data Gated Route To
..---------------------------------------------------------- ---------------- POC-1 0 FREE NO
[TIMESERIES]
;;Name Date Time Value
..--------------------------------------------
OCEANSIDE FILE "K:\Library\Stormwater\SWMM\RAIN GAGES\Oceanside Rain Data.dat" [REPORT]
;;Reporting Options

INPUT NO

CONTROLS NO

SUBCATCHMENTS ALL

NODES ALL

LINKS ALL
11 /15/2022 PH 1 Page 995 of 1307

[TAGS]
[MAP]
DIMENSIONS 191.920 4920.830 1021.827 5718.627
Units None
[COORDINATES]
;;Node X-Coord Y-Coord
..-------------------------------- ------------------
POC-1 757.069 4959.747
[VERTICES]
;;Link X-Coord Y-Coord
..--------------------------------------------------
[Polygons]
;;Subcatchment X-Coord Y-Coord
..-------------------------------- ------------------
DMA-1 706.040 5124.523
BYPASS2 804.759 5127.873
[SYMBOLS]
;;Gage X-Coord Y-Coord
..-------------------------------- ------------------
OCEANSIDE 757.548 5779.526
11 /15/2022 PH 1 Page 996 of 1307

POST -DEVELOPED RUNOFF CONDITION (POC-2) OUTPUT FILE
EPA STORM WATER MANAGEMENT MODEL - VERSION 5.1 (Build 5.1.012) -------------------------------------------------------------- Camino Largo, Vista, CA Post -Developed Mitigated Runoff Condition - POC 2 WARNING 04: minimum elevation drop used for Conduit BYPASS-2 WARNING 04: minimum elevation drop used for Conduit DUM 2 NOTE: The summary statistics displayed in this report are based on results found at every computational time step, not just on results from each reporting time step.

Analysis Options
Flow Units ...............

CFS
Process Models:

Rainfall/Runoff ........

YES
RDII ...................

NO
Snowmelt ...............

NO
Groundwater ............

NO
Flow Routing ...........

YES
Ponding Allowed ........

NO
Water Quality ..........

NO
Infiltration Method ......

GREEN_AMPT
Flow Routing Method ......

KINWAVE
Starting Date ............
08/28/1951 05:00:00
Ending Date ..............
05/23/2008 23:00:00
Antecedent Dry Days ......

0.0 Report Time Step .........
01:00:00
Wet Time Step ............
00:15:00
Dry Time Step ............
04:00:00
Routing Time Step ........

60.00 sec
11 /15/2022 PH 1 Page 997 of 1307

**************************
Volume
Depth
Runoff Quantity Continuity
**************************
acre-feet
inches
Initial LID Storage ......
---------

0.029
-------

0.068
Total Precipitation ......
284.559
675.110
Evaporation Loss .........

26.243

62.262
Infiltration Loss ........
160.973
381.906
Surface Runoff ...........

22.730

53.926
LID Drainage .............

3.397

8.058
Final Storage ............

74.291
176.254
Continuity Error (o) .....
-1.070
**************************
Volume
Volume
Flow Routing Continuity
**************************
acre-feet
---------
10^6 gal
---------
Dry Weather Inflow .......

0.000

0.000
Wet Weather Inflow .......

26.126

8.514
Groundwater Inflow .......

0.000

0.000
RDII Inflow ..............

0.000

0.000
External Inflow ..........

0.000

0.000
External Outflow .........

26.126

8.514
Flooding Loss ............

0.000

0.000
Evaporation Loss .........

0.000

0.000
Exfiltration Loss ........

0.000

0.000
Initial Stored Volume ....

0.000

0.000
Final Stored Volume ......

0.000

0.000
Continuity Error (o) .....

0.000
********************************
Highest Flow Instability Indexes
********************************
All links are stable.
*************************
Routing Time Step Summary
*************************
Minimum
Time Step

60.00 sec
Average
Time Step

60.00 sec
Maximum
Time Step

60.00 sec
Percent
in Steady State

0.00 Average
Iterations per Step

1.00 11 /15/2022 PH 1 Page 998 of 1307

Percent Not Converging 0.00
***************************
Subcatchment Runoff Summary
***************************
-------------------------------------------------------------------------------------------------------- Total
Total
Total
Total
Total
Total
Peak
Runoff
Precip
Runon
Evap
Infil
Runoff
Runoff
Runoff
Coeff
Subcatchment
in
in
in
in
in
10^6 gal
CFS
-------------------------------------------------------------------------------------------------------- DMA-2
675.11

0.00 52.68
201.79
429.22

36.67 3.71

0.636
BMP-2
675.11
6339.49
606.44
2033.37
191.36

1.11 0.10

0.027
BYPASS2
675.11

0.00 11.78
508.39
160.54

7.41 1.91

0.238
***********************
LID Performance Summary
-------------------------------------------------------------------------------------------------------------------- Total
Evap
Infil
Surface
Drain
Initial
Final Continuity
Inflow
Loss
Loss
Outflow
Outflow
Storage
Storage Error
Subcatchment LID Control in
in
in
in
in
in
in o
-------------------------------------------------------------------------------------------------------------------- BMP-2 BMP-2 675.11
461.60

0.00 0.00
213.41

1.80 1.89 0.00
Node Depth Summary
******************
--------------------------------------------------------------------------------- Average
Maximum
Maximum
Time
of Max
Reported
Depth
Depth
HGL
Occurrence
Max Depth
Node
Type
Feet
Feet
Feet
days
hr:min
Feet
--------------------------------------------------------------------------------- POC-1

OUTFALL

0.00 0.00

0.00 0
00:00

0.00 DIV-2

DIVIDER

0.00 0.00

0.00 0
00:00

0.00 STOR-2

STORAGE

0.00 0.00

0.00 0
00:00

0.00 Node Inflow Summary
11 /15/2022 PH 1 Page 999 of 1307

------------------------------------------------------------------------------------------------- Maximum
Maximum
Lateral
Total
Flow
Lateral
Total
Time of Max
Inflow
Inflow
Balance
Inflow
Inflow
Occurrence
Volume
Volume
Error
Node
Type
CFS
CFS
days hr:min
10^6 gal
10^6 gal
Percent
------------------------------------------------------------------------------------------------- POC-1

OUTFALL

1.91 1.91
18857 12:01

7.41 8.51

0.000
DIV-2

DIVIDER

0.10 0.10
10002 09:31

1.11 1.11

0.000
STOR-2

STORAGE

0.00 0.00
0 00:00
0 0

0.000 gal
Node Flooding Summary
*********************
No nodes were flooded.
**********************
Storage Volume Summary
-------------------------------------------------------------------------------------------------- Average
Avg
Evap
Exfil
Maximum
Max
Time of Max
Maximum
Volume
Pcnt
Pcnt
Pcnt
Volume
Pcnt
Occurrence
Outflow
Storage Unit 1000 ft3
Full
Loss
Loss
1000 ft3
Full
days hr:min
CFS
-------------------------------------------------------------------------------------------------- STOR-2 0.000
0 0
0 0.000
0 0 00:00

0.00 ***********************
Outfall Loading Summary
***********************
----------------------------------------------------------- Flow
Avg
Max
Total
Freq
Flow
Flow
Volume
Outfall Node Pcnt
CFS
CFS
10^6 gal
----------------------------------------------------------- POC-1 0.66

0.10 1.91

8.513
----------------------------------------------------------- System 0.66

0.10 1.91

8.513
11 /15/2022 PH 1 Page 1000 of 1307

********************
Link Flow Summary
----------------------------------------------------------------------------- Maximum
Time of Max Maximum Max/ Max/
IFlowl
Occurrence IVelocl Full Full
Link
Type
CFS
days hr:min ft/sec Flow Depth
----------------------------------------------------------------------------- BYPASS-2
DUMMY

0.00 0 00:00
DUM_2
DUMMY

0.10 10002 09:31
STOR-2-ORIFICE
DUMMY

0.00 0 00:00
Conduit Surcharge Summary
*************************
No conduits were surcharged.

Analysis begun on: Fri Dec 03 17:24:45 2021
Analysis ended on: Fri Dec 03 17:25:39 2021
Total elapsed time: 00:00:54
11 /15/2022 PH 1 Page 1001 of 1307

ATTACHMENT 10
Drawdown Calculations
11 /15/2022 P� 1 Page 1002 of 1307

Drawdown Calculations
Note: Drawdown calculations are from invert of lowest surface discharge opening in riser structure to the surface bottom of the basin. Therefore, discharge occurs only through the underdrain orifice.

Drawdown Calculations for BMP 1

ORIFICE FLOW
Surface Ponding Depth:

PD
6 in
Ponding Depth Surface Area:

APp
6147
ft2
Surface Ponding Volume:

VPo
2408
ft3
Low Flow Orifice Diameter:

4.00 in
Flow Rate (volumetric):

0.371
ft3/s
Drawdown Time:

1.81 hrs
INFILTRATION CONTROLS✓
Surface Ponding Depth:

PD
6 in
Ponding Depth Surface Area:

APo
6147
ft2
Surface Ponding Volume:

VPp
2408
ft3

INFILTRATION RATE
1 5.00
in/hr
Flow Rate (volumetric):

0.711
ft3/s
Drawdown Time:

0.94 hrs
11 /15/2022 PH 1 Page 1003 of 1307

Drawdown Calculations for BMP 2

ORIFICE FLOW
Surface Ponding Depth:

PD
6 in
Ponding Depth Surface Area:

APp
9279
ft'
Surface Ponding Volume:

VPp
2408
ft3
Low Flow Orifice Diameter:

3.00 in
Flow Rate (volumetric):

0.371
ft3/s
Drawdown Time:

1.81 hrs
INFILTRATION CONTROLS✓
Surface Ponding Depth:

PD
6 in
Ponding Depth Surface Area:

APp
9279
ft2
Surface Ponding Volume:

VPp
2408
ft3

INFILTRATION RATE
1 5.00
in/hr
Flow Rate (volumetric):

1.074
ft3/s
Drawdown Time:

0.62 hrs
11 /15/2022 PH 1 Page 1004 of 1307

ATTACHMENT 3 - BMP MAINTENANCE INFORMATION
Each of the attachments indicated below should be considered for inclusion with the SWAMP. Use this checklist to indicate which attachments are included behind this coversheet.

Attachment
Sequence
Contents
Checklist
Attachment 3A
Structural BMP Operations
❑X Included
and Maintenance Plan
See Structural BMP Maintenance Information
Checklist on the back of this Attachment cover sheet.

Attachment 3B
Draft Maintenance
0 Included
Agreement
❑ Not Applicable

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11 /15/2022 PH 1 Page 1005 of 1307

ATTACHMENT 3A — MAINTENANCE PLAN REQUIREMENTS
For Attachment 3A, provide a BMP operation and maintenance plan (0&M Plan). The checklist below identifies minimum elements to be included with the 0&M Plan. An 0&M Plan template is available at:
http://www.citVofvista.com/services/city-departments/community-development/building-planning- permits-applications/land-development-autocad-templates/storm-water-forms ❑X Specific maintenance indicators and actions for proposed structural BMP(s). This shall be based on Section 7.7 of the BMP Design Manual and enhanced to reflect actual proposed components of the structural BMP(s)
0 Use of 0&M Plan template, or plan of equivalent content

Page 56 of 73 ends

11 /15/2022 PH 1 Page 1006 of 1307

BF-1
Biofiltration

BMP MAINTENANCE FACT SHEET
FOR
STRUCTURAL BMP BF-1 BI OFI LTRATION
Biofiltration facilities are vegetated surface water systems that filter water through vegetation, and soil or engineered media prior to discharge via underdrain or overflow to the downstream conveyance system.

Biofiltration facilities have limited or no infiltration_ They are typically designed to provide enough hydraulic head to move flows through the underdrain connection to the storm drain system. Typical Biofiltration components include:
■ Inflow distribution mechanisms (e.g, perimeter flow spreader or filter strips) • Energy dissipation mechanism for concentrated inflows (e.g., splash blocks or riprap) ■ Shallow surface ponding far captured flows
• Side slope and basin bottom vegetation selected based on climate and ponding depth • Non -floating mulch layer
■ Media layer (planting mix or engineered media) capable of supportingvegetation growth • Filter course layer consisting of aggregate to prevent the migration of fines into uncompacted native soils or the aggregate storage layer
■ Aggregate storage layer with underdraIn(s)
• Impermeable liner or uncompacted native soils at the bottom of the facility ■ Overflow structure
Normal Expected Maintenance
Biofiltration requires routine maintenance to: remove accumulated materials such as sediment, trash or debris; maintain vegetation health; maintain infiltration capacity of the media layer, replenish mulch; and maintain Integrity of side slopes, inlets, energy dissipators, and outlets. A summary table of standard inspection and maintenance indicators is provided within this Fact Sheet.

Non -Standard Maintenance or BMP Failure
If any of the following scenarios are observed, the BMP is not performing as intended to protect downstream waterways from pollution and/or erosion. Corrective maintenance, increased inspection and maintenance, BMP replacement, ar a different BMP type will be required.

The BMP is not drained between storm events. Surface ponding longer than approximately 24 hours following a storm event may be detrimental to vegetation health, and surface ponding longer than approximately 96 hours foIlowing a storm event poses a risk of vector (mosquito) breeding. Poor drainage can result from clogging of the media layer, filter course, aggregate storage layer, underdrain, or outlet structure. The specific cause of the drainage issue must be determined and corrected.

Sediment, trash, or debris accumulation greater than 25% of the surface ponding volume within one month. This means the load from the tributary drainage area is too high, reducing BMP function or clogging the BMP. This would require pretreatment measures within the tributary area draining to the BMP to intercept the materials. Pretreatment components, especially for sediment, will axtend the life of components that are more expensive to replace such as media, filter course, and aggregate layers.

Erosion due to concentrated storm water runoff flow that is not readily corrected by adding erosion control blankets, adding stone at flow entry points, or minor re -grading to restore proper drainage according to the original plan. If the issue is not corrected by restoring the BMP to the original plan and grade, the [City Engineer] shall be contacted prior to any additional repairs or reconstruction.

BF-1 Page 1 of 11
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BF-1
Biofiltration
Other Spode Corrsiderations
Biofiltration is a vegetated structural BMP. Vegetated structural BMP& that are constructed in the vicinity of, or connected to, an existingjurisdictionaI water or wetland could inadvertently result in creation of expanded waters or wetlands. As such, vegetated structural BM Ps have the potential to come under the jurisdiction of the United States Army Corps of Engineers, SIDRWQCB, California Department of Fish and Wildlife, or the United States Fish and Wildlife Service. This could result in the need for specific resource agency permits and costly mitigation to perform maintenance of the structural BMP. Along with proper placement of a structural BMP, routine maintenance is key to preventingthis scenario.

BF-1 Page 2 of 11
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BF-1
Biofiltration
SUMMARY OF STANDARD INSPECTION AND MAINTENANCE FOR BF-1 BIOFI LTRAT ION The property owner is responsible to ensure inspection, operation and maintenance of permanent BMPs on their property unless res po n si h i lity has heen formal lytransferred to a n age n cy, com m u n ity faci I it ies d istrict, homeowners associat bo n, p ro pe rty ow n e rs a sso ci at i o n, o r of h er s pecia I d ist rict.

MaIntenancefrequencies listed in this table are a ve rageAypi ca I frequencies. Actual maintenance needs are site -specific, and maintenance may be required more frequently.

Maintenance must he performed whenever needed, ha sed on maintenance indicators presented in this table. The B M P owner is responsible for conducting regular inspections to see when maintenance is needed based an the maintenance indicators. Du ring the first year of operation of a structural BMP, inspection is recommended at least once prior to August 31 and then monthly from September through May. Inspection during a storm ere nt is also recommended. After the initial period of frequent inspections, the minimum inspection and maintenance frequency can be determined based an the results of the first year inspections.

ThresholdlIndkator
MaintenanceAct ion
Typical Maintenance Frequency
Accumulation of sediment, litter, or debris
Remove and properly dispose of accumulated materials,
• Inspect monthly. If the BMP is 25% full' or more in
without damage to the vegetation or compaction of the
one month, increase inspection frequency to monthly
media layer.
plusafter every 0.1-inch or Iargerstorm event.
• Remove any accumulated materials found at each
inspection.

Obstructed inlet or outlet structure
Clear blockage.
• Inspect monthly and after every 0.5-inch or larger
storm event.
• Remove any accumulated materials found at each
inspection.

Damage to structural components such as weirs, inlet or Repair or replace as applicable
• Inspect annually.
outlet structures
• Maintenance when needed.

Poor vegetation establishment
Re -seed, re -plant, or re-establish vegetation per original • Inspect monthly.
plans.
• Maintenance when needed.

Dead or diseased vegetation
Remove dead or diseased vegetation, re -seed, re -plant, • Inspect monthly.
or re-establish vegetation per original plans.
• Maintenance when needed.

Overgrown vegetation
Mow or trim as appropriate.
• Inspect monthly.
• Maintenance when needed.
2/3 of mulch has decomposed, or mulch has been
Remove decomposed fraction and top off with fresh
Inspect monthly.
removed
mulch to a total depth of 3 inches.
• Replenish mulch annually, or more frequently when
needed based on inspection.
•"25%fuII' is defined as 34 of the depth from the design bottom elevation to the crest of the outflow structure (e.g., if the height to the a utf low o pen i ng is 12 inches from the bottom elevation, then the materials must be removed when there is 3 inches of accumulation —this should he marked on the outflow structure).

BF-1 Page 3 of 11
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11 /15/2022 PH 1 Page 1009 of 1307

BF-1
Biofiltration
SUMMARY OF STANDARD INSPECTION AND MAINTENANCE FOR BF-1 81ORLTRATI0N [Continued from previous page] Thresholdlinclkator
Maintenance Action
Typical Maintenance Frequency
Erosion due to concentrated irrigation flaw
Repair/re-seed/re-plant eroded areas and adjust the
• Inspect monthly.
irrigation system.
• Maintenance when needed.

Erosion due to concentrated storm water runoff flow
Repairlre -se edlre-plant eroded areas, and make
• Inspect after every 0.5-inch or larger storm event. if appropriate corrective measures such as adding erosion
erosion due to storm water flow has been Observed,
control blankets, adding stone at flow entry points, or increase inspection frequency to after every 0-1-inch
minor regrading to restore proper drainage according
or larger storm event.
to the original plan. If the issue is not corrected by
. Maintenance when needed. If the issue is not
restoring the BMP to the original plan and grade, the
corrected by restoring the BMP to the original plan
[City Engineer] shall be contacted prior to any additional and grade, the [City Engineer] shall be contacted prior repairs or reconstruction.
to any additional repairs or reconstruction.

Standing water in BMP for longer than 24 hours
Make appropriate corrective measures such as adjusting
• Inspect monthly and after every 0.5-inch or larger
fallowing a storm event
irrigation system, removing obstructions of debris or
storm event. If standing water is observed, increase
Surface ponding longer than approximately 24 hours
invasive vegetation, clearing underdrains, or
inspection frequency to after every 0-1-inch or larger
repairingfreplacingclogged or compacted soils.
storm event.
following a storm event may be detrimental to
• Maintenance when needed.
vegetation health
Presence of mosquitos larvae
If mosquitosilarvae are observed: first, immediately
• Inspect monthly and after every 0.5-inch or larger
remove any standing water by dispersing to nearby
storm event. If mosquitos are observed, increase
For images of egg rafts, larva, pupa, and adult
landscaping; second, make corrective measures as
inspection frequency to after every 0.1-inch or larger
mosquitos, see
applicable to restore BMP drainage to prevent standing
storm event.
htto:ll www.mosguito.orelbioloey
water.
• Maintenance when needed.

If mosquitos persist fallowing corrective measures to
remove standing water, or if the BMP design does not
meet the 95-hour drawdown criteria due to release
rates controlled by an orifice installed on the
underdrain, the [City Engineer] shall be contacted to
determine a solution. A different BMP type, or a Vector Management Plan prepared with concu rrence fro m the
County of San Diego Department of Environmental
Heakh, may be required.

Underdrain clogged
Clear blockage.
• Inspect if standing water is observed for longer than 2 4-9 5 hours foIIowinga storm event.
• Maintenance when needed.

BF-1 Page 4 of 11
January 12, 2017

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11 /15/2022 PH 1 Page 1010 of 1307

BF-1
Biofiltration
References
American Mosquito Control Association.
http ://www. m osq u [to-or�j
California Storm Water Quality Association (CASQ4). 2003. Municipal B M P Handbook. httos:// www.casoa.orOresources/bmo-handbookslmunicioaI-bmp-hand book County of San Diego. 2014. Low Impact Development Handbook. h tto 7//www.sa nd ieeocounty. epV /opnte nt/sd c/d o w/wa tersh e d s/su sm pA id. htm I San Diego County Copermittees. 2016. Model BMP Design Manual, Appendix E, Fact Sheet BF-1- http-:// www.proiectcleanwater.org(Index.php?option=com content&view=article&id=250&ltemid=220 BF-1 Page 5 of 11
January 12, 2017

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Page Intentionally Blank for Double -Sided Printing
BF-1 Page 5of 11
January 12, 2017

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BF-1
Bidiltration
11/15/2022 PH1 Page 1012 of 1307

BF-1
Biofiltration
Date:

Inspector: BMP ID No.:

Permit No.:

APN(s):

Property/ Development Name,
Responsible Party Name and Phone Number,
Pro perty Ad d ress of BMP:

Responsible PartyAddress:

INISPECTIC, N AND MAINTENANCE CHECKLIST FOR BF-1 BIO FI LTRATIO N PAGE 1 of 5 Threshold/Indicator
MaiMenanee Recommendation
Date
Description of Maintenance ConduRed
Accumulation of sediment, litter, or debris
LJ Remove and properly dispose of
Maintenance Needed?
accumulated materials, without damage
tothe vegetation
❑ YES
I I NO
LJ If sediment, litter, or debris accumulation
exceeds 25'%of the surface ponding

I I NIA
volume within one month (25%full'),
add a fo re bay o r other pre-treatment
measures within the tributary area
draining to the BMP to intercept the
materials.

I I other/Comments:

Poor vegetation establishment
Fl Re seed, re -plant, or re-estah Iish
Maintenance Needed?
vegetation peroriginal plans
Fl YES
❑ other/Comments:
❑ NO
❑ NIA
* "25%full" is defined as 34 of the depth from the design bottom elevation to the crest of the outflow structure (e.g., if the height to the a utf low o pen i ng is 12 inches from the bottom elevation, then the materials must he removed when there is 3 inches of accumulation —this should he marked on the outflow structure).

BF-1 Page 7 of 11
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11 /15/2022 PH 1 Page 1013 of 1307

BF-1
Biofiltration
Date: Inspector: BMP ID No.:

Permit No.: APNtsj:

INSPECTION AND MAINTENANCE CHECKLIST FOR BF-1 BI 0 FI LTRATIO N PAGE 2 of 5 Threshold/Indicator
Maintenance Recommendation
Date
Description of Maintenance Conducted
Dead or diseased vegetation
LJ Remove dead or diseased vegetation, re -
Maintenance Needed?
seed, re -plant, or re-establish vegetation
per original plans
LJ YES
I 1 other/Comments:

Fl No
Fl N/A
overgrown vegetation
❑ Mow or trim as appropriate
Maintenance Needed?
❑ Other/Comments:
❑ YE5
❑ NO

I I N/A
2/3 of mulch has decomposed, or mulch has
❑ Remove decomposed fraction and top off
been removed
with fresh mulch to a total depth of 3
Maintenance Needed?
inches
❑ YE5
❑ Othe r / Comments:
❑ NO
❑ N/A
BF-1 Page 8 of 11
January 12, 2017

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11 /15/2022 PH 1 Page 1014 of 1307

BF-1
Biofiltration
Date: Inspector: BMP ID No.:

Permit No.: APN(s):

INSPECTION AND MAINTENANCE CHECKLIST FOR BF-1 BI 0 FI LTRATIO N PAGE 3 of 5 Threshold/Indicator
Maintenance Recommendation
Date
Description of Maintenance Conducted
Erasion due to concentrated irrigation flow
LJ Repair/re-seed/re-plant eroded areas and
Maintenance Needed?
adjust the irrigation system
LJ YES
I-1 Other/Comments:
rl NO
rl N/A
Erosion due to concentrated storm water runoff
LJ Repair/re-seed/re-plant eroded areas,
flow
and make appropriate corrective
Maintenance Needed?
measures such as adding erosion
control blankets, adding stone at flow
❑ yE5
entry points, or minor re-gradingto
I I No
restore properdrainageaccordingta
❑ NIA
the original plan

1. 1 If the issue is not corrected by restoring
the BMP to the original plan and grade,
the [City Engineer] shall be contacted
prior to any additional repairs or
reconstruction
Fl Other / Comm ents:

BF-1 Page 9 of 11
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BF-1
Biofiltration
Date: Inspector: BMP ID No.:

Permit No.: APN(s):

INSPECTION AND MAINTENANCE CHECKLIST FOR BF-1 BI0FILTRATION PAGE 4 of 5 Threshold/Indicator
Maintenance Recommendation
Date
Description of Maintenance Conducted
Obstructed inlet or outlet structure
❑ Clear blockage
Maintenance Needed?
❑ other/Comments:

LJ YES
Fl No
Fl N/A
underdrain clogged (inspect underdrain it
LJ Clear blockage
standing water is observed for longer than 24-96
hours foIlowinga storm event)
❑ Other/Comments:

Maintenance Needed?
❑ YES
LJ NO
❑ N/A
Damage to structural components such as weirs,
Fl Repair or replace as applicable
inlet or outlet structures
❑ Other/Comments:

Maintenance Needed?

I I YES
❑ NO
Fl N/A
BF-1 Page 10 of 11
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11 /15/2022 PH 1 Page 1016 of 1307

BF-1
Biofiltration
Date: Inspector: BMP €D No.:

Permit No.: APNtsj:

INSPECTION AND MAINTENANCE CHECKLIST FOR BF-1 BI 0 FI LTRATIO N PAGE 5 of 5 Threshold/Indicator
Maintenance Recommendation
Date
Description of Maintenance Conducted
Standing water in BMP for longer than 24-96
LJ Make appropriate corrective measures
hours foIlowinga storm event'
such as adjusting irrigation system,
Surface ponding longer than approximately 24
removing obstructionsof dehris or
hours following storm event may he
invasive vegetation, clearing
detrimental to vegett ation heahh
underdrains, or repairingJreplacing
clogged or compacted sails
Maintenance Needed?
n Other JComm errts:
❑ YES
IINO
I 1 N/A
Presence of mosquitos/larvae
I I Apply corrective measuresto remove
standing water in BMP when standing
For images of egg rafts, larva, pupa, and adult
wate r occu rs fo r longer t h a n 24-96
mosquitos, see
hoursfollowing a storm event.—
Other/Comments-
Maintenance Needed?

I I YES
n NO
n N/A
•Surface pond ing longer than a pp roximate ly 24 hou rs fo I lowi n g a storm event may be detrimental to vegetation health, and surface ponding longer than approximately 96 hours following a storm event poses a risk of vector [mosquito} breeding. Poor drainage can result from clogging of the media layer, filter course, aggregate storage layer, underdrain, or outlet structure. The spec6ccause of the drainage issue must be determined and corrected. —If mosquitos persist fallowing corrective measures to remove standing water, or if the BMP design does not meet the 96-hour drawdown criteria due to release rates controlled by an orifice installed on the underdrain, the [City Engineer] shall be contacted to determine a solution. A different BMP type, or a Vector Management Plan prepared with concu rrence from the County of San Diego Department of Environmental Health, may be required.

BF-1 Page 11 of 11
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ATTACHMENT 3B — MAINTENANCE AGREEMENT
All projects are required to maintain designed functionality of structural BMPs in perpetuity. Privately - owned projects must record a Storm Drain Maintenance Agreement with the County of San Diego Assessor's Office. A template Storm Drain Maintenance Agreement is available at:

I. Purpose and Scope
This section was prepared based on the Chapter 7 of the City of Vista BMP Design Manual. The goal is to insure that the Project proponent accepts responsibility for all facilities maintenance, repair, and replacement from the time they are constructed until the ownership and maintenance responsibilities is formally transferred to the new owner. Facilities shall be maintained in perpetuity and comply with the City's self -inspection, reporting, and verification requirements.

II. Inspection, Maintenance Log and Self -Verification Forms Fill the forms in the Structural BMP Maintenance Plan (Attachment 3a) for each BMP using the maintenance schedule and the inspection -maintenance checklists. These forms shall be signed by the responsible party and retained for at least (5) years. Use the DMA Exhibit for the location of BMPs. (Make duplicate copies of these forms and fill out those, not the original ones.)
III. Updates, Revisions and Errata
This maintenance plan is a living document and based on the changes made by maintenance personnel, such as replacement of mechanical equipment, addition maintenance procedure shall be added and maintenance plan shall be kept up to date.

Please add the revisions and updates to the maintenance plan to this section if any, these revisions maybe transmitted to the City at any time. However, at a minimum, updates to the maintenance plan must accompany the annual inspection report.

IV. Introduction
The Camino Largo Project proposes the development of a forty six (46) lot residential subdivision, with individual level building pads on 8.86 gross acres. The project also proposes the minor widening and improvement of the Camino Largo private drive, which will include paving, sidewalks with curb and gutter.

The graded site will include forty six (46) new residential lots with driveways and landscaping areas along five (5) streets north of Camino Largo. Approximately 53% of the property will be impervious. Biofiltration basins are proposed for the two main drainage basins for POC-1 and POC-2. Proposed grading has been minimized as much as possible to maintain existing slope and drainage patterns.

V. Responsibility for Maintenance
A. General
Kyun Tae Kim and Frank Sohaei, Trustee of the Falor Family Trust will enter into a Stormwater Facilities Maintenance Agreement (SWFMA) with the City of Vista to maintain designated facilities herein this section for the Camino Largo Project.

The SWFMA will serve as the mechanism to ensure that proper inspection and maintenance is done in an efficient and timely manner.

Responsible Party
Kyun Tae Kim
Frank Sohaei, Trustee of the Falor Family Trust
2359 Pio Pico Drive
Carlsbad, CA 92008

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11 /15/2022 PH 1 Page 1019 of 1307

POC-1
There is one (1) biofiltration basin which will outlet into an existing storm drain along -side North Santa Fe Avenue south of Camino Largo and discharge from the site at POC-1.

POC-2
(760) 420-1267
Kyun Tae Kim and Frank Sohaei, Trustee of the Falor Family will have the direct responsibility for maintenance of Stormwater controls. Funding for the maintenance activities shall be provided by Camino Largo Project or other mechanism to the satisfaction of the City.

Whenever the property is sold and whenever designated individual change, immediately the updated contact information must be provided to the City of Vista.

The Camino Largo Project falls within the "Second Category" of the City of Vista (City) Maintenance Mechanism because the use of biofiltration basins are Best Management Practices (BMPs). The developer would provide the City with security to substantiate the maintenance agreement, which would remain in place for 5 years. The amount of the security would equal the estimated cost of 2 years of maintenance activities.

The security can be a cash deposit, letter of credit, or other form acceptable to the City. If a stormwater utility or other permanent mechanism is put into place, it could assume either a primary or backup maintenance role.

B. Staff Training Program
Staff training and education program shall be carried out twice a year, once prior to the rainy season (October 1 St) and once during the early dry season (April 3011) The inspection and maintenance training program consists of the operation and function of the biofiltration basins. Please refer to the Structural BMP Maintenance Plan (Attachment 3a) for fact sheets and checklists.

It is the responsibility of 1017 Sycamore Avenue to convey the maintenance and inspection information to the employees. Maintenance personnel must be qualified to properly maintain stormwater management facilities.

Inadequately trained personnel can cause additional problems resulting in additional maintenance costs.

C. Records
Kyun Tae Kim and Frank Sohaei, Trustee of the Falor Family Trust shall retain education, inspection, and maintenance forms and documents for at least five (5) years.

D. Safety
Keep safety considerations at the forefront of inspection procedures at all times. Likely hazards should be anticipated and avoided. Never enter a confined space (outlet structure, manhole, etc.) without proper training or equipment. A confined space should never be entered without at least one additional person present.

If a toxic or flammable substance is discovered, leave the immediate area and contact the local Sheriff at 911.

Potentially dangerous (e.g., fuel, chemicals, hazardous materials) substances found in the areas must be referred to the local Sheriff's Office immediately for response by the Hazardous Materials Unit. The emergency contact number is 911.

VI. Summary of Drainage Areas and Stormwater Facilities A. Drainage Areas
POC-1
DMA 1 will drain into a biofiltration basin which will outlet into an existing storm drain along -side North Santa Fe Avenue south of Camino Largo and discharge from the site at POC-1.

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POC-2
DMA 2 will drain into a biofiltration basin, which outlets via a storm drain into a natural swale at POC-2.

B. Treatment and Flow -Control Facilities
The BMP biofiltration basins in DMA 1 and DMA 2 are responsible for handling hydromodification requirements for POC-1 and POC-2. Basins 1 and Basin 2 will have a ponding depth of 6 inches. BMPs are comprised of an 18-inch layer of amended soil (a highly sandy, organic rich compost with an infiltration capacity of at least 5 in/hr), and a 7-inch reservoir layer of gravel for additional detention, and to accommodate the French drain system. Below the reservoir layer, the basins will include 3 inches of saturated storage.

Flows will discharge from the basin via a low -flow orifice outlet within the gravel layer to the receiving storm drain system. A riser structure will be constructed within the BMP with multiple low -flow orifices and an emergency overflow, such that peak flows can be safely discharged to the storm drain system.

VII. Facility Documentation
Please see Structural BMP Maintenance Plan (Attachment 3a) regarding BMPs details and maintenance fact sheets.

Vill. Maintenance Schedule and Checklist
Fill out the Checklists in the Structural BMP Maintenance Plan (Attachment 3a) for each BMP. The required maintenance activities are at the end of the section. At the discretion of the project proponent, a qualified stormwater company may be hired to perform the required inspection and maintenance and provide necessary reports.

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EXHIBIT: STORM WATER BMP SHEET

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-1.111970 WE,
- - - - - - - - - -
WWAM
OrNOS

MAINTENANCE INDICATORS AND ACTIONS FOR

BIOFILTRATION BMPS

TYPICAL MAINTENANCE INDICATORS

TYPICAL MAINTENANCE ACTIONS
ACCUMULATION OF SEDIMENT (OVER 2

REMOVE AND PROPERLY DISPOSE OF

INCHES DEEP OR COVERS VEGETATION),

ACCUMULATED MATERIALS WITHOUT

LITTER, OR DEBRIS
DAMAGE TO THE VEGETATION. CONFIRM

THAT SOIL IS NOT CLOGGING AND THAT THE
AREA DRAINS AFTER STORM EVENT. TILL OR
REPLACE SOIL AS NECESSARY.

POOR VEGETATION ESTABLISHMENT

ENSURE VEGETATION IS HEALTHY AND

DENSE ENOUGH TO PROVIDE FILTERING AND
TO PROTECT SOILS FROM EROSION.

REPLENISH MULCH AS NECESSARY (IF LESS
THAN 3 INCHES DEEP), REMOVE FALLEN

LEAVES AND DEBRIS, PRUNE LARGE SHRUBS
OR TREES, AND MOW TURF AREAS.

OVERGROWN VEGETATION -WOODY

MOW OR TRIM AS APPROPRIATE, BUT NOT

VEGETATION NOT PART OF DESIGN IS

LESS THAN THE DESIGN HEIGHT OF THE

PRESENT AND GRASS EXCESSIVELY TALL
VEGETATION (TYPICALLY 4-6 INCHES FOR
(GREATER THAN 10 INCHES)
GRASS). CONFIRM THAT IRRIGATION IS

ADEQUATE AND NOT EXCESSIVE AND THAT

SPRAYS DO NOT DIRECTLY ENTER
OVERFLOW GRATES. REPLACE DEAD PLANTS

AND REMOVE NOXIOUS AND INVASIVE
WEEDS.

EROSION DUE TO CONCENTRATED

REPAIR/RE-SEED ERODED AREAS AND

IRRIGATION FLOW
ADJUST THE IRRIGATION.

EROSION DUE TO CONCENTRATED

REPAIR/RE-SEED ERODED AREAS AND MAKE

STORMWATER RUNOFF FLOW

APPROPRIATE CORRECTIVE MEASURES SUCH

AS ADDING EROSION CONTROL BLANKETS,

ADDING STONE AT ENTRY POINTS, OR
RE -GRADING WHERE NECESSARY. REMOVE

OBSTRUCTIONS AND SEDIMENT
ACCUMULATIONS SO WATER DISPERSES.

STANDING WATER (BMP NOT DRAINING). IF

WHERE THERE IS AN UNDERDRAIN, SUCH AS

MOSQUITO LARVAE ARE PRESENT AND

IN PLANTER BOXES AND MANUFACTURED

PERSISTENT, CONTACT THE SAN DIEGO

BIDFILTERS, CHECK THE UNDERDRAIN PIPING
VECTOR CONTROL PROGRAM AT (858)

TO MAKE SURE IT IS INTACT AND
694-2888. MOSQUITO LARVICIDES SHOULD
UNOBSTRUCTED. ABATE ANY POTENTIAL

BE APPLIED ONLY WHEN ABSOLUTELY

VECTORS BY FILLING HOLES IN THE GROUND

NECESSARY AND THEN ONLY BY A LICENSED

IN AND AROUND THE BIOFILTER FACILITY
INDIVIDUAL CONTRACTOR.

AND BY INSURING THAT THERE ARE NO

AREAS WHERE WATER STANDS LONGER
THAN 96 HOURS FOLLOWING A STORM.

OUTLET INLET OR OUTLET STRUCTURE
CLEAR OBSTRUCTIONS.

DAMAGE TO STRUCTURAL COMPONENTS
REPAIR OR REPLACE AS APPLICABLE.

SUCH AS WEIRS, INLET, OR OUTLET

STRUCTURES

BEFORE THE WET SEASON AND AFTER RAIN

WHERE CISTERNS ARE PART OF THE SYSTEM
EVENTS: REMOVE SEDIMENT AND DEBRIS

FROM SCREENS AND OVERFLOW DRAINS
AND DOWNSPOUTS: ENSURE PUMPS ARE
FUNCTIONING, WHERE APPLICABLE; CHECK
INTEGRITY OF MOSQUITO SCREENS; AND;

CHECK THAT COVERS ARE PROPERLY SEALED
AND LOCKED.

TYPE G-2 CATCH BASIN
PER D-8

OUTFLOW
THREE (3) 12" RCP �.

OUTLET PIPES
30 ML

IMPERMEABLE
LINER* EXIST. GROUND
n
E
3" MULCH

DEEP ROUTED, DENSE,

DROUGHT TOLERANT

PLANTING SUITABLE FOR

WELL DRAINED SOIL
18" AMENDED SOIL MIN. INFILTRATION RATE 5"/HR
LEGEND
FREEBOARD = 12.00" (CONJUNCTIVE USE FACILITY)
O BASIN HEIGHT HMAx = 30.00"
' O3 PONDING DEPTH = 6.00"
I
O RISER INVERT HTOP = 18.00"
_ 4" PEA GRAVEL
I O5 *EMERGENCY WEIR INVERT = 18.00"
U R 7" GRAVEL LAYER O *LOWER SLOT INVERT = 6.00"
FOR V2 STORAGE 1 — 5" HIGH X 34" LONG OPENING
7O *UPPER SLOT INVERT = 7.00"
6" PERFORATED PVC PIPE 1 — 4" HIGH X 10" LONG OPENING
III — i CONFORMING TO ASTM D PC POLLUTANT CONTROL WSEL = 6.00" 3034 OR EQUIVALENT
RESTRICTER CAP TO LIMIT FLOW 3" DEAD STORAGE HC HYDROMODIFICATION CONTROL WSEL = 13.92" OUT OF V2 STORAGE AREA, LID BELOW UNDERDRAIN
DRAIN DOWN HOLE, d = 4.00" FC FLOOD CONTROL WSEL = 18.00" BIOFILTRATION BASIN DETAIL, BMP 1

NOT TO SCALE
*30 MILLINER NOTE: 30—MIL IMPERMEABLE LINER FOR BIORETENTION CONFORM TO THE FOLLOWING SPECIFICATIONS: SPECIFIC GRAVITY (ASTM D792): 1.2 (G/CC, MIN.); TENSILE (ASTM D882): 73 (LB/IN—WIDTH, MIN); ELONGATION AT BREAK (ASTM D882): 380 (%, MIN); MODULUS (ASTM D882):
30 (LB/IN—WIDTH, MIN.); AND TEAR STRENGTH (ASTM D1004): 8 (LB/IN, MIN); SEAM SHEAR STRENGTH (ASTM D882) 58.4 (LB/IN, MIN); SEAM PEEL STRENGTH (ASTM D882) 15 (LB/IN, IN).

SEE COLORADO LINING INTERNATIONAL PVC 30
HTTP: //WWW.COLORADOLINING.COM/PRODUCTS/PVC.PDF) OR APPROVED EQUAL. 0 OUTFLOW
TWO (2) 12" RCP

OUTLET PIPES
30 ML

IMPERMEABLE
LINER*
ljj_�
EXIST. GROUND
TYPE G-1 CATCH BASIN
PER D-8
9 3" MULC

DEEP ROUTED, DENSE,

DROUGHT TOLERANT

PLANTING SUITABLE FOR

WELL DRAINED SOIL
18" AMENDED SOIL MIN. INFILTRATION RATE 5"/HR

RESTRICTER CAP TO LIMIT FLOW
OUT OF V2 STORAGE AREA, LID
DRAIN DOWN HOLE, d = 3.00"
=I
144" PEA GRAVEL
=I I
7" GRAVEL LAYER
FOR V2 STORAGE
6" PERFORATED PVC PIPE
i CONFORMING TO ASTM D
3034 OR EQUIVALENT
'-3" DEAD STORAGE

BELOW UNDERDRAIN
BIOFILTRATION BASIN DETAIL, BMP 2

SEE COLORADO LINING INTERNATIONAL PVC 30
HTTP: //WWW.COLORADOLINING.COM/PRODUCTS/PVC.PDF) OR APPROVED EQUAL.

MALE NATIONAL PIPE THREAD

PVC ADAPTER CAST

IN SIDE OF RISER WALL
/— RISER WALL
*ELEVATION MEASURED FROM BASIN SURFACE
LEGEND
10 FREEBOARD =

12.00" (CONJUNCTIVE USE FACILITY)
O2 BASIN HEIGHT
HMAx = 30.00"
O3 PONDING DEPTH = 6.00"

THREADED FEMALE NATIONAL

PIPE THREAD PVC CAP
WITH DRILLED ORIFICE 6" FRENCH DRAIN,
L _jPERFORATED PVC PIPE b h A i
n c ,
d °QG Dafnd p0annhg0 dA enghec dingo surveyhg
III=1 I I i 11-1 11-
11 —III—III 5115 AVENIDA ENCINAS
SUITE 1"
BOTTOM OF BASIN CARLSBAD, CA. 92008-4387
(760) 931-8700
- d d
a
a
d d d a d C
a ° Q
a
a
d Q
6" PERFORATED PVC PIPEUNDERDRAIN ORIFICE d BMP EXHIBIT
THREADED FEMALE NATIONAL 'a °
PIPE THREAD PVC CAP a d a a CAMINO LARGO
WITH DRILLED ORIFICE a d
a
RESTRICTOR CAP DETAIL BMP 1 & 2

NOT TO SCALE
K:\Cililf\6��bg'� G\SWMP\BMP-TSM.dwg, 12/7/2021 11:47:08 AM PH 1 Page 1024 of 1307

ATTACHMENT 4 - REQUIREMENTS FOR CONSTRUCTION PLANS
Section 8.2.2 of the BMP Design Manual identifies minimum requirements for storm drain construction plan sheets. Use this checklist to ensure project construction plans submitted for review include necessary information for storm drain improvements. Construction plans must include the following:
0 All items identified in Section 8.2.2 of the BMP Design Manual.

Page 73 of 73 ends

11 /15/2022 PH 1 Page 1025 of 1307

VISTA

IRRIGATION

VIDDISTRICT

CAMINOLARGO WATER SUPPLYSTUDY
LN 2021-038
November 15, 2021
Prepared By: Robert Scholl, P.E.

Approvals: 9t_

GENERAL POLICY STATEMENT
This water supply study is based on current criteria. It is not a representation, expressed or implied, that the Vista Irrigation District (District) will furnish water at a future date. Applications for service are governed by separate rules and regulations, and are the subject of separate District proceedings, apart from this water supply study.

The location of existing improvements and the recommendations of this hydraulic analysis are presented in schematic form only. It is the responsibility of the Developer/Engineer to design the final improvements, including independent investigation of existing conditions.

This Study is based on the current adopted land use utilized in the City of Vista's General Plan 2030 (General Plan). The study addresses the incremental facility impacts of this Project only and does not include or consider any additional projects within District's service area that have deviated from General Plan land uses. Any land use changes within the vicinity of the Study area may necessitate a revision to the Study. The District shall determine if and when revisions to the Study are necessary. Costs for revising this Study shall be borne by the Developer.

INTRODUCTION AND PURPOSE
The proposed development on the north side of Camino Largo (Project) is a single-family subdivision consisting of 46 dwelling units on approximately 9.3 acres (APN 159-240-07). The property is located adjacent to and east of N. Santa Fe Drive and was within the unincorporated County of San Diego and its North County Metro subplan; however, on October 1, 2018, the San Diego Local Agency Formation Commission approved the annexation of the property into the City of Vista. The Project is also located within the District's Sphere of Influence and water service boundary.

The purpose of this study is to serve as a nexus document for setting development conditions. It evaluates the configuration of the proposed water system, District service rights, and the ability of the existing water distribution system to serve the Project during peak hour and maximum day plus fire flow demand conditions. Evaluation includes:
➢ Water distribution system; including the need to upsize or install new pipelines and appurtenances.
11/15/2022 PH1 Page 1026 of 1307

Camino Largo Water Supply Study
October 28, 2021

Page 2 of 7 ends

➢ Access and utility easements; including evaluation of the adequacy of existing easements, and the need for new easements.

SOURCE OF WATER, PROPOSED FACILITIES, AND EASEMENTS
The proposed Project lies completely within the District's 565 Pressure Zone, which is supplied from the 3.1 million gallon (MG) San Luis Rey Reservoir, the 0.6 MG E-1 Reservoir and multiple pressure regulating stations. Figures 1 through 3 show the development's location, existing water infrastructure within the vicinity of the development, and proposed facilities.

The site supported agricultural uses and is served by a 2-inch meter (account #9995-0950) that is connected to the District's 10-inch pipeline within N. Santa Fe Avenue. Based on the Tentative Subdivision Map provided by the Developer, a public water system is proposed through the project; the water system would connect to the District's existing system within N. Santa Fe Avenue along the western end of the Project. The District reviewed this configuration and finds it suitable for a single-family residential development of this size. The District will require full width (curb to curb) access and utility easements over all private roads within the development.

WATER FLOW PROJECTIONS AND DESIGN CRITERIA
The Project's land use designation by the City of Vista's General Plan 2030 is Rural Residential, which allows up to one dwelling unit per acre. The Project developer is proposing to build 46 single-family residences on 9.3 acres, which equates to approximately five dwelling units per acre.

To meet the new density requirements, the developer is proposing a General Plan Amendment to adjust the land use to Medium Density Residential, which would allow up to ten dwelling units per acre.

Based on the unit demand factor of 1,100 gallons per day (gpd)/acre developed in the Master Plan for single-family residential land use and site size of 9.3 acres, the projected average annual water demand for the Project is 10,230 gpd.

The Master Plan outlines the District's water system design criteria, which are as follows:

Peaking Factors
➢ Maximum day demands:
➢ Peak hour demands:

System Pressure
➢ Peak hour demand conditions:
➢ Maximum day demand plus fire flow
➢ Static:

Fire Flow
200% of average annual demands
300% of average annual demands
40 pounds per square inch (psi) minimum
20 psi minimum
150 psi maximum
➢ The City of Vista Fire Marshal has set the required fire demand at 1,500 gallons per minute (gpm) for the Project.
11/15/2022 PH1 Page 1027 of 1307

Camino Largo Water Supply Study
October 28, 2021

Page 3 of 7 ends

Pipeline Fluid Velocity
➢ Peak hour demand conditions:
➢ Maximum day demand plus fire flow
Pipeline Diameter
➢ Short dead-end, no hydrants:
➢ Feeding hydrants:

HYDRAULIC ANALYSES
8 feet per second (fps) maximum
16 fps maximum
4-inch diameter minimum
8-inch diameter minimum
A hydraulic analysis was performed on the District's distribution system with the proposed Project's water demands and facilities incorporated. The Project proposes a 2,400-foot, 8-inch diameter water system extension within the development, connecting to the District's 10-inch pipeline within N. Santa Fe Avenue as shown in the Tentative Subdivision Map and Figure 3. Two fire hydrants are proposed within the development on Camino Largo to provide fire protection.

The analysis was carried out using the District's InfoWater® 02.4 water distribution computer model. The modeled pressure results at each of the two proposed fire hydrants to be installed and the high point within the development are summarized in the table below.

Hydraulic Modeling Results
Elevation Static Peak Hour Max Day +
Node Location (ft) Pressure Pressure FF Pressure
(psi) (psi) (psi)*
VID Pipe @ Fire 300 115 107 97
Hydrant #1
VID Pipe @ Fire 316 108 100 82
Hydrant #2
VID Pipe @ High 345 95 88 N/A
Point of Development
*Simulated fire flows are within the distribution system water mains, analyses do not represent actual flow available through a fire hydrant assembly or fire sprinkler system.

No existing system deficiencies were identified in any pipe segments within the Project limits or in the vicinity of the development during any scenario. Results from the analysis show that the required fire flow demand of 1,500 gpm can be met at both proposed fire hydrants on Camino Largo.

The District makes no guarantee that the available fire flow and pressures are presently available, nor guarantee that the flow and pressure will be available in the future due to continued growth that places additional demands for water on the water distribution system. Availability of flow and pressure is also subject to shutdowns and variations required by the operation of the District's distribution system.
11/15/2022 PH1 Page 1028 of 1307

Camino Largo Water Supply Study
October 28, 2021

Page 4 of 7 ends

CONCLUSION AND CONDITIONS
The proposed Project is proposing a General Plan Amendment to adjust the land use to allow up to ten dwelling units per acre. Based on the unit demand factor of 1,100 gpd/acre for single-family residential land use and a site size of 9.3 acres, the projected average annual water demand for the Project is 10,230 gpd.

The Study did not identify any existing system deficiencies within the Project limits or in the vicinity of the development during peak hour demand or maximum day plus fire flow demand scenarios. The following improvements were assumed to be constructed as part of this development:
➢ The installation of approximately 2,400-feet of public 8-inch pipeline within the Project that will connect to the District's existing 10-inch water main in N. Santa Fe Drive. 11 /15/2022 PH 1 Page 1029 of 1307

Camino Largo Water Supply Study
October 28, 2021

Page 5 of 7 ends

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11 /15/2022 PH 1 Page 1030 of 1307

Camino Largo Water Supply Study
October 28, 2021

Page 6 of 7 ends

11 /15/2022 PH 1 Page 1031 of 1307

Camino Largo Water Supply Study
October 28, 2021

Page 7 of 7 ends

11 /15/2022 PH 1 Page 1032 of 1307

IS/MND Appendix G
Noise Assessment Study
11 /15/2022 PH 1 Page 1033 of 1307

11 /15/2022
HELIX
Environmental Planning
Camino Largo Residential
Project
Noise Assessment Study
December 2021 1 02951.00013.001
Submitted to:

City of Vista
Community Development Department
200 Civic Center Drive
Vista, CA 92084-6275
Prepared for:

California West Communities
5927 Priestly Drive, Suite 110
Carlsbad, CA 92008
Prepared by:

HELIX Environmental Planning, Inc.
7578 El Cajon Boulevard
La Mesa, CA 91942
PH1 Page 1034 of 1307

TABLE OF CONTENTS
Section Page
EXECUTIVE SUMMARY............................................................................................................................. ES-1

1.0 INTRODUCTION................................................................................................................................1

1.1 Purpose of the Report.........................................................................................................1

1.2 Project Location..................................................................................................................1

1.3 Project Description.............................................................................................................1

1.4 Noise and Sound Level Descriptors and Terminology........................................................1

1.4.1 Descriptors.............................................................................................................1

1.4.2 Terminology...........................................................................................................2

1.5 Noise and vibration -Sensitive Land Uses............................................................................3

1.6 Regulatory Framework.......................................................................................................3

1.6.1 California Noise Control Act...................................................................................3

1.6.2 City of Vista General Plan, Noise Element.............................................................3

1.6.3 City of Vista Noise Ordinance (Municipal Code, Chapter 8.32, Noise Control) ..... 4 2.0 ENVIRONMENTAL SETTING..............................................................................................................6

2.1 Surrounding Land Uses.......................................................................................................6

2.2 Existing Noise Environment................................................................................................6

2.2.1 Ambient Noise Survey............................................................................................6

3.0 ANALYSIS, METHODOLOGY, AND ASSUMPTIONS............................................................................7

3.1 Methodology.......................................................................................................................7

3.1.1 Ambient Noise Survey............................................................................................ 7 3.1.2 Noise Modeling Software......................................................................................8

3.2 Assumptions........................................................................................................................8

3.2.1 Construction..........................................................................................................8

3.2.2 Operations.............................................................................................................9

3.3 Guidelines for the Determination of Significance.............................................................10

4.0 1 M PACTS.........................................................................................................................................11

4.1 Issue 1: Excessive Noise Levels.........................................................................................11

4.1.1 Operational On -site Noise Generation................................................................11

4.1.2 Operational Off -site Transportation Noise Generation.......................................11

4.1.3 On -site Construction Noise Generation...............................................................12

4.1.4 Construction Traffic Noise...................................................................................15

4.2 Issue 2: Excessive Vibration..............................................................................................15

4.2.1 Construction Vibration.........................................................................................15

4.2.2 Operational Vibration..........................................................................................15

4.3 Issue 3: Airport Noise Exposure........................................................................................16

4.3.1 Aircraft Noise.......................................................................................................16 i
11 /15/2022 PH 1 Page 1035 of 1307

TABLE OF CONTENTS (cont.

Section Page

4.4 Issue 4: Noise Compliance for New Uses..........................................................................16

4.4.1 Exterior Noise Levels............................................................................................16

4.4.2 Interior Noise Levels............................................................................................17

5.0 LIST OF PREPARERS........................................................................................................................17

6.0 REFERENCES...................................................................................................................................18

LIST OF APPENDICES
A Carrier 38HDR060 Split System Condenser
B Construction Noise Modeling Outputs

LIST OF FIGURES
No. Title Follows Page
1 Regional Location.............................................................................................................................2 2 Project Vicinity................................................................................................................................. 2 3 Site Plan........................................................................................................................................... 2

LIST OF TABLES
No.

Title
Page
1 Interior and Exterior Noise Guidelines............................................................................................4 2 Applicable Exterior Property Line Noise Limits
................................................................................ 5 3 Maximum Sound Levels (Impulsive)................................................................................................ 6 4
Noise Measurement Results............................................................................................................7 5 Recorded Traffic Volume and Vehicle Mix....................................................................................... 7 6
Carrier HDR060 Condenser Noise.................................................................................................... 9 7
Existing Plus Project Traffic Volumes............................................................................................... 9 8
Off -site Traffic Noise Levels........................................................................................................... 12 9
Construction Equipment Noise Levels...........................................................................................13 ii
11 /15/2022 PH 1 Page 1036 of 1307

ACRONYMS AND ABBREVIATIONS
ADT
average daily traffic
ANSI
American National Standards Institute
APN
Assessor's Parcel Number
Caltrans
California Department of Transportation
CEQA
California Environmental Quality Act
City
City of Vista
CNEL
Community Noise Equivalent Level
CY
cubic yard
dB
decibel
dBA
A -weighted decibel
HVAC
heating, ventilation, and air conditioning
Hz
Hertz
kHz kilohertz
LDN
Day -Night level
LEQ
equivalent sound level
LLG
Linscott, Law and Greenspan, Engineers
LMAX
maximum noise level
mPa micro -Pascals
mph miles per hour
NSLU noise -sensitive land use
PPV
peak particle velocity
RCNM
Roadway Construction Noise Model
SPL
sound pressure level
STC
Sound Transmission Class
SwL
sound power level
TNM
Traffic Noise Model
USDOT
U.S. Department of Transportation
iii
11 /15/2022 PH 1 Page 1037 of 1307

This page intentionally left blank
iv
11 /15/2022 PH 1 Page 1038 of 1307

Camino Largo Residential Project Noise Assessment Study I December 2021

EXECUTIVE SUMMARY
This report presents an assessment of potential noise impacts associated with the proposed Camino Largo Residential Project (project). The project is located on a 9.3-acre project site in the City of Vista.

The project site is located at the northeast corner of North Santa Fe Avenue and Camino Largo. The project involves removal of structures associated with an existing nursery and the construction of 46 two-story single-family residential units.

Anticipated construction activities would generate temporary elevated noise levels for nearby residences to the west and south. Although the use of construction equipment is not anticipated to exceed City noise ordinance limits, construction noise may exceed ambient conditions by 10 dBA.

Mitigation measure NOI-1 would reduce noise impacts to less than significant levels. Construction would not generate substantial vibration.

Operational noise impacts would be less than significant. The project's heating, ventilation, and air conditioning (HVAC) systems would not exceed allowable City limits within the noise ordinance at the nearest property lines. The project would add traffic to nearby roadways, but transportation noise impacts to off -site land uses would be less than significant.

The backyard exterior use areas of the proposed residences at Lots 1 and 2 would be exposed to noise from vehicular traffic along North Santa Fe Avenue that would exceed the applicable 65 Community Noise Equivalent Level (CNEL) limit set forth in the City of Vista's General Plan Noise Element. Mitigation measure NOI-2 would be required to construct barriers and reduce noise levels to the 65 CNEL exterior limit at these locations. Through incorporation of mitigation measure N0I-3, which relates to exterior wall and window construction, interior noise levels at Lots 1 and 2 would not exceed the applicable interior 45 CNEL limit for residential uses.

HELIX
Environmental Planning
11 /15/2022
PH1

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Camino Largo Residential Project Noise Assessment Study I December 2021 HELIX
Environmental Planning
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Camino Largo Residential Project Noise Assessment Study I December 2021

1.0 INTRODUCTION

1.1 PURPOSE OF THE REPORT
This report analyzes potential noise and vibration impacts associated with the proposed Camino Largo Residential Project (project). The analysis includes a description of existing conditions in the project vicinity and an assessment of potential impacts associated with project implementation. Analysis within this report addresses the relevant issues listed in the Noise and Land Use sections of Appendix G of the California Environmental Quality Act (CEQA) Guidelines.

1.2 PROJECT LOCATION
The 9.3-acre project site (Assessor's Parcel Number [APN] 159-240-07) is located northeast of the intersection of North Santa Fe Avenue and Camino Largo in the City of Vista (City), south of the City's boundary with the County of San Diego. Guajome Adobe Park is located to the west and rural single- family residences and undeveloped land are to the south and east. See Figure 1, Regional Location, and Figure 2, Project Vicinity.

The existing site contains remnants of the former nursery, including hoop frames of the former greenhouses, palm trees in box planters, and piles of green waste. There is a structure that is associated with the former nursery operations located in the south-central portion of the site and trucks and machinery scattered throughout the site.

1.3 PROJECT DESCRIPTION
The project would construct 46 two-story single-family residential units. Access would be provided by four private drives extending north from Camino Largo. Resident parking would be provided via two -car garages and individual driveways, with additional parking provided along one side of each private drive.

The project would provide two water quality/retention basins onsite. One is located on the southwest corner of the site and another at the southeast edge of the site. See Figure 3, Site Plan.

The project site is currently occupied by an active palm nursery. The project would involve the demolition of existing structures which includes a greenhouse and shed. The project would require an amendment to the City General Plan from Rural Residential (R-R) to Medium Density Residential (MDR) and a zone change from A-1 to R-113.

1.4 NOISE AND SOUND LEVEL DESCRIPTORS AND TERMINOLOGY

1.4.1 Descriptors
All noise level or sound level values presented herein are expressed in terms of decibels (dB), with A -weighting (dBA) to approximate the hearing sensitivity of humans. Time -averaged noise levels are expressed by the symbol LEQ, with a specified duration. The Community Noise Equivalent Level (CNEL) is a 24-hour average, where noise levels during the evening hours of 7:00 p.m. to 10:00 p.m. have an added 5 dBA weighting, and noise levels during the nighttime hours of 10:00 p.m. to 7:00 a.m. have an added 10 dBA weighting. This is similar to the Day Night sound level (LDN), which is a 24-hour average with an added 10 dBA weighting on the same nighttime hours but no added weighting on the evening HELIX
Environmental Planning
11 /15/2022
PH1

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Camino Largo Residential Project Noise Assessment Study I December 2021 hours. Sound levels expressed in CNEL are always based on dBA. These metrics are used to express noise levels for both measurement and municipal regulations, as well as for land use guidelines and enforcement of noise ordinances

1.4.2 Terminology

1.4.2.1 Sound, Noise, and Acoustics
Sound can be described as the mechanical energy of a vibrating object transmitted by pressure waves through a liquid or gaseous medium (e.g., air) to a hearing organ, such as a human ear. Noise is defined as loud, unexpected, or annoying sound.

In the science of acoustics, the fundamental model consists of a sound (or noise) source, a receiver, and the propagation path between the two. The loudness of the noise source and obstructions or atmospheric factors affecting the propagation path to the receiver determines the sound level and characteristics of the noise perceived by the receiver. The field of acoustics deals primarily with the propagation and control of sound.

1.4.2.2 Frequency
Continuous sound can be described by frequency (pitch) and amplitude (loudness). A low -frequency sound is perceived as low in pitch. Frequency is expressed in terms of cycles per second, or Hertz (Hz) (e.g., a frequency of 250 cycles per second is referred to as 250 Hz). High frequencies are sometimes more conveniently expressed in kilohertz (kHz), or thousands of Hertz. The audible frequency range for humans is generally between 20 Hz and 20,000 Hz.

Sound Pressure Levels and Decibels
The amplitude of pressure waves generated by a sound source determines the loudness of that source.

Sound pressure amplitude is measured in micro -Pascals (mPa). One mPa is approximately one hundred billionth (0.00000000001) of normal atmospheric pressure. Sound pressure amplitudes for different kinds of noise environments can range from less than 100 to 100,000,000 mPa. Because of this wide range of values, sound is rarely expressed in terms of mPa. Instead, a logarithmic scale is used to describe sound pressure level (SPL) in terms of dBA. The threshold of hearing for the human ear is about 0 dBA, which corresponds to 20 mPa.

1.4.2.3 Addition of Decibels
Because decibels are logarithmic units, SPL cannot be added or subtracted through standard arithmetic.

Under the decibel scale, a doubling of sound energy corresponds to a 3 dBA increase. In other words, when two identical sources are each producing sound of the same loudness, the resulting sound level at a given distance would be 3 dBA higher than from one source under the same conditions. For example, if one automobile produces an SPL of 70 dB when it passes an observer, two cars passing simultaneously would not produce 140 dBA—rather, they would combine to produce 73 dBA. Under the decibel scale, three sources of equal loudness together produce a sound level 5 dBA louder than one source.

Under controlled conditions in an acoustical laboratory, the trained, healthy human ear is able to discern 1 dBA changes in sound levels, when exposed to steady, single -frequency ("pure -tone") signals in the mid -frequency (1,000 Hz to 8,000 Hz) range. In typical noisy environments, changes in noise of HELIX
Environmental Planning
11 /15/2022
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RIVERSIDE
COUNTY

ORANGE SAN DIEGO

COUNTY COUNTY
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Environmental Planning
11 /15/2022 PH 1 Page 1043 of 130jigure 1

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Environmental Planning
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Site Plan

Page 1045 of 130 ends

Camino Largo Residential Project Noise Assessment Study I December 2021 1 to 2 dBA are generally not perceptible. It is widely accepted, however, that people begin to detect sound level increases of 3 dB in typical noisy environments. Further, a 5 dBA increase is generally perceived as a distinctly noticeable increase, and a 10 dBA increase is generally perceived as a doubling of loudness.

No known studies have directly correlated the ability of a healthy human ear to discern specific levels of change in traffic noise over a 24-hour period. Many ordinances, however, specify a change of 3 CNEL as the significant impact threshold. This is based on the concept of a doubling in noise energy resulting in a 3 dBA change in noise, which is the amount of change in noise necessary for the increase to be perceptible to the average healthy human ear.

1.5 NOISE AND VIBRATION -SENSITIVE LAND USES
Noise -sensitive land uses (NSLUs) are land uses that may be subject to stress and/or interference from excessive noise, including residences, hospitals, schools, hotels, resorts, libraries, sensitive wildlife habitat, or similar facilities where quiet is an important attribute of the environment. Noise receptors are individual locations that may be affected by noise. NSLUs in the project vicinity include single-family residences to the north, south, and east.

Land uses in which ground -borne vibration could potentially interfere with operations or equipment, such as research, manufacturing, hospitals, and university research operations (Federal Transit Administration [FTA] 2018) are considered "vibration -sensitive." The degree of sensitivity depends on the specific equipment that would be affected by the ground -borne vibration. In addition, excessive levels of ground -borne vibration of either a regular or an intermittent nature can result in annoyance to residential uses or schools. Vibration -sensitive land uses in the project area include the nearby single- family residences.

1.6 REGULATORY FRAMEWORK

1.6.1 California Noise Control Act
The California Noise Control Act is a section within the California Health and Safety Code that describes excessive noise as a serious hazard to the public health and welfare and that exposure to certain levels of noise can result in physiological, psychological, and economic damage. It also finds that there is a continuous and increasing bombardment of noise in the urban, suburban, and rural areas. The California Noise Control Act declares that the State of California has a responsibility to protect the health and welfare of its citizens by the control, prevention, and abatement of noise. It is the policy of the State to provide an environment for all Californians free from noise that jeopardizes their health or welfare.

1.6.2 City of Vista General Plan, Noise Element
The Noise Element of the City's General Plan includes a noise/land use compatibility matrix for assessing the suitability of different categories of planned land uses based on exterior noise level exposure (Table NE-3 from the City General Plan; City 2012). For the project's land use (Single Family Residential), the Noise Element specifies exterior noise levels up to 60 CNEL as normally acceptable and up to 70 CNEL is conditionally acceptable. Noise levels exceeding 70 CNEL are generally unacceptable for single-family residential uses.

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Camino Largo Residential Project Noise Assessment Study I December 2021 In addition, the City defines specific maximum noise levels that shall not be exceeded for both interior and exterior use areas. A proposed project shall not generate noise levels that exceed these standards.

The City limits interior noise levels to 45 CNEL for single-family residential development. Table 1, Interior and Exterior Noise Guidelines, provides limits for various types of land uses.

Table 1

INTERIOR AND EXTERIOR NOISE GUIDELINES
Land Use
Maximum Noise Level
(LDN or CNEL, dBA)
interiorl,Z
Maximum Noise Level
(Lon, or CNEL, dBA)
Exterior
Residential —Single Family, Multi -family, Duplex
45 653
Residential — Nursing Homes, Hospital
45 653
Private Offices, Church Sanctuaries, Libraries, Board
Rooms, Conference Rooms, Theaters, Auditoriums,
Concert Halls, Meeting Halls, etc.
45 -
Schools
45 654
General Offices, Reception, Clerical, etc.
50 -
Bank Lobby, Retail Store, Restaurant, Typing Pool, etc. 60 Manufacturing, Kitchen, Warehousing, etc.
65 -
Parks, Playgrounds, etc.
-
654
Golf Courses, Outdoor Spectator Sports, Amusement
Parks, etc.
70 4
Source: City 2012
1 Noise standard with windows closed. Mechanical ventilation shall be provided per UBC requirements to provide a habitable environment.
z Indoor environment excluding bathrooms, toilets, closets, and corridors. 3 Outdoor environment limited to rear yard of single-family homes, multi -family patios and balconies (with a depth of 6 feet or more) and common recreation areas.
4 Outdoor environment limited to playground areas, picnic areas, and other areas of frequent human use.

LDN=Day-Night Level; CNEL=Community Noise Equivalent Level; dBA=A-weighted decibel

1.6.3 City of Vista Noise Ordinance (Municipal Code, Chapter 8.32, Noise Control)
Sections 8.32.010 through 8.32.060 of the City of Vista Municipal Code pertain to City noise requirements and enforcement of violations. The City has adopted the County of San Diego Noise Ordinance for the purpose of controlling excessive noise levels, including noise from construction activities.

Table 2, Applicable Exterior Property Line Noise Limits, lists the applicable exterior property line noise limits. This table is specific to the City of Vista and replaces the table in Section 36.404 of the County of San Diego noise ordinance. It is unlawful for any person to cause or allow the creation of any noise to the extent that the one -hour average sound level at any point on or beyond the boundaries of the property exceeds these limits. The sound level limit at a location on a boundary between two zones is the arithmetic mean of the respective limits for the two zones.

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Vista City CouncilNovember 15, 2022

Vista City Council
November 15, 2022