HomeMy WebLinkAboutHMP 15-01; MARTIN RESIDENCE; SWMM MODELING FOR HYDROMODIFICATION COMPLIANCE; 2017-03-01RECORD COPY
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Initial Date
TECHNICAL MEMORANDUM:
SWMM Modeling for
Hydromodification Compliance of:
Martin Residence
Carlsbad, CA
Prepared for:
MAR 14 Z01
Caroline & Neil Martin CT'( OF CARLSBAD
March 1, 2017
No. 45005
Exp. 3-31-2018
0---~
1
~ v
R. Walker, R.C. E. 45005
President
TORY R.WALKER ENGINEERING
RELIABLE SOLUTIONS IN WATER RESOURCES
122 CIVIC CENTER DR, STE 206, VISTA, CA 92084 760-414-9212
p,o )q—o5
TORY R.WALKER ENGINEERING
RELIABLE SOLUTIONS IN WATER RESOURCES
TECHNICAL MEMORANDUM
TO: Caroline & Neil Martin
1878 Shadetree Drive
San Marcos, CA 92078
FROM: Tory Walker, PE, CFM, LEED GA
DATE: MARCH 1, 2017
RE: Summary of SWMM Modeling for Hydromodification Compliance of the Martin
Residence, City of Carlsbad, CA.
INTRODUCTION
This technical memorandum summarizes the approach used to model the proposed Martin Residence
project in the City of Carlsbad, CA, using the Environmental Protection Agency (EPA) Storm Water
Management Model 5.1 (SWMM). SWMM analyses were prepared for the pre- and post-developed
conditions at the project site to determine if the proposed underground storage vault meets
Hydromodification Management Plan (HMP) requirements. The San Diego Regional Water Quality
Control Board (SDRWQCB) established these requirements in the Model BMP Design Manual San Diego
Region' (BMPDM) for the County of San Diego Copermittees, which includes the City of Carlsbad.
SWMM MODEL DEVELOPMENT
The Martin Residence project proposes to develop an existing site, which is currently undeveloped,
located on Adams Street, east of its interception with Highland Drive, in the City of Carlsbad. Two (2)
SWMM scenarios were prepared for this study, one for the pre-developed and another for the post-
developed conditions. One Point of Compliance (POC-1) has been identified for the project site, as
shown on the exhibits in Attachment 5. For both SWMM scenarios, flow duration curves were prepared
for POC-1 to determine if the proposed underground vault is sufficient to meet the current HMP
requirements.
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 used 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 provided in the BMPDM. The
existing condition site was modeled with Type D hydrologic soil, as determined from the Natural
Resources Conservation Service (NRCS) Web Soil Survey. Type B soil has been assumed in post-
developed conditions to account for the anticipated fill soils onsite, as required by the BMPDM.
WATERSHED, FLOODPLAIN &STORM WATER MA NAG EMENT RIVER RESTORATION FLOOD FACILITIES DESIGN SEDIMENT & EROSION
122 Civic CENTER DRIVE, SUITE 206, VISTA CA 92084 760-414-9212 TRWENGINEERING.COM
liii..... I Martin Residence HMP Memo
______ November 30, 2016
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HMP MODELING
POC-1 is located along the southeastern project site boundary (see Site maps in Attachment 5). In
existing conditions, the undeveloped DMA 1 drains southerly to POC-1. In proposed conditions, the
developed area tributary to POC-1 is drained to underground vault (Hydromodification BMP). Once flow
is routed via the proposed BMP, the flow is then discharged to POC-1. Tables 1.1 and 1.2 summarize
data for the POC-1 DMAs.
The underground vault is responsible for handling hydromodification requirements for POC-1 and has
been designed with a maximum surface ponding depth of 4.00 feet. Flows will discharge from the basin
via orifice outlets and a weir within the ponding depth of the vault, to POC-1 at the project boundary.
An outlet structure will be constructed within the BMP with an emergency weir, such that peak flows
can be safely discharged to POC-1 (see dimensions in Tables 2 and 3 below).
TABLE 1.1 - SUMMARY OF EXISTING CONDITIONS FOR POC-1
DMA Tributary Area, A (ac) Impervious Percentage, Ip
DMA 1 0.1970 0.0%
TABLE 1.2 - SUMMARY OF DEVELOPED CONDITIONS FOR POC-1
DMA Tributary Area, A (ac) Impervious Percentage, Ip12
DMA 1 0.1852 79.1%
BY-PASS 1 0.0006 100.0%
TOTAL 0.1858* -
*Lower area total in the developed condition is the result of the self retaining pool area being removed from totals
General Considerations
The vault was modeled using the storage element within SWMM. The storage element can model the
vault 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.
Detailed water quality requirements are not discussed within this technical memo. For further
information regarding storm water quality requirements for the project, please refer to the site specific
Storm Water Quality Management Plan (SWQMP).
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BMP MODELING FOR HMP PURPOSES
Modeling HMP BMPs
An underground storage vault is proposed for hydromodification conformance for the project site.
Tables 2 and 3 illustrate the dimensions required for HMP compliance according to the SWMM models
that were undertaken for the project.
TABLE 2— SUMMARY OF HYDROMODIFICATION BMP: Storage Vault
BMP
BMP DIMENSIONS FOR POC-1
Vault Surface Area (ft2) 1 Vault Depth (if)
1 335 4
TABLE 3— SUMMARY OF HMP RISER SURFACE DISCHARGE STRUCTURES
OUTLET DIMENSIONS FOR POC-1
BMP LOWER ORIFICE UPPER ORIFICE EMERGENCY WEIR
Dimensions Dimensions
Inv. El. (if) Inv. El. (if) Inv. EI.(ft) Length (if) (# - diameter (in)) (# - diameter (in))
1 1-0.3125 0 1-0.25 3.5 3.75 4
FLOW DURATION CURVE COMPARISON
A Flow Duration Curve (FDC) was compared at the project's POC by exporting the hourly runoff time
series results from SWMM to a spreadsheet. The FDC was compared between 10% of the existing
condition 02 up to the existing condition Q. The 02 and O.io were determined with a partial duration
statistical analysis of the runoff time series in an Excel spreadsheet using the Cunnane plotting position
method (which is the preferred plotting methodology in the HMP Permit). As the SWMM Model
includes a statistical analysis based on the Weibull Plotting Position Method, the Weibull Method was
also used within the spreadsheet to ensure that the results were similar to those obtained by the
SWMM Model.
The range from 10% of Q2 up to 010 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 (Q 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 for POC-1 is illustrated in
Figure 1 in both normal and logarithmic scale.
As can be seen in Figure 1, the FDC for the proposed condition with the HMP facility is 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
10% 0.2 lower threshold. Additionally, the project will maintain peak flow rates between the Q2 and the
010, as shown in the graphics and also in the peak flow tables in Attachment 1.
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November 30, 2016
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SUMMARY
This study has demonstrated that the proposed underground vault provided within the Martin
Residence project is sufficient to meet the current HMP criteria if the cross-sectional area and volume
recommended within this technical memorandum, and the respective orifices and outlet structures, are
incorporated as specified within the proposed project site.
KEY ASSUMPTIONS
1. Type B soils are representative of the existing condition site per the NRCS Web Soil Survey.
4 Job #439-01
Martin Residence HMP Memo
November 30, 2016
Flow Duration Curve - Martin Residence (POC-1)
0131 -
-- E E E 011
0.10 f %...:_
09 f - - =_• ------------Existing -
- - - - Proposed
0.08 t
._0.07 - ..- - - - -- - - .- - .--
----------------
0.05 t
-
-
0.03f052--- --- - -- --__
0.02
0.015------f-
O.1j ------------------------------- -------- ----------------- ----------------
0.5))
0.081 0.01
Percentage of time exceeded (%)
Flow Duration Curve - Martin Residence (POC-1)
0.12
::--- -------------------------------:: : :::::: : ::: : : :::: :.:am Q7
0.10 -:.;--.:;: :- ;-:. ----------
- =
4 1
008
- LTT T T +T -0.06 - - Existing
----Proposed
---Qx
0.04 - - - •- - -------+ --- -
xz.: ----------------
0.02 o:3 ==-----------.. =f=—
'- I
0.04 -------- --.--------------+------ _. -- -_-_,_ ._-._-________
0 0.01 0.02 0.03
Percentage of time exceeded (%)
Figure 1. Flow Duration Curve Comparison for POC-1 (logarithmic and normal "x" scale).
5 Job #439-01
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November 30, 2016
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REFERENCES
[1] - "Model BMP Design Manual San Diego Region - For Permanent Site Design, Storm Water
Treatment, and Hydromodification Management", June 2015, Geosyntec Consultants & Rick
Engineering Company.
[21 - Order 119-2013-001, California Regional Water Quality Control Board San Diego Region
(SDRWQCB).
- "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.
- "Handbook of Hydrology", David R. Maidment, Editor in Chief. 1992, McGraw Hill.
ATTACHMENTS
Q2 to Q10 Comparison Tables
FDC Plots (log and natural "x" scale) and Flow Duration Tables.
List of the "n" largest Peaks: Pre-Developed and Post-Developed Conditions
Elevation vs. Area Curves and Elevation vs. Discharge Curves to be used in SWMM
Existing and Developed Condition Maps, Project plan and section sketches
SWMM Input Data in Input Format (Existing and Developed Models)
SWMM Screens and Explanation of Significant Variables
Soil Map
Summary files from the SWMM Model
6 Job It 439-01
ATTACHMENT 1
Q2 to Q10 Comparison Tables
Q to Q10 Comparison Table - POC-1
Return Period Existing Condition (cfs) Mitigated Condition (cfs) Reduction, Exist -
Mitigated (cfs)
2-year 0.064 0.034 0.030
3-year 0.079 0.046 0.033
4-year 0.094 0.068 0.027
5-year 0.099 0.073 0.026
6-year 0.102 0.074 0.028
7-year 0.110 0.090 0.019
8-year 0.113 0.091 0.022
9-year 0.116 0.095 0.021
10-year 0.120 0.107 0.014
ATTACHMENT 2
FDC Plots (log and natural "x" scale) and Flow Duration Table
ATTACHMENT 2
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, for each POC, the flow duration curve in post-
development conditions with the proposed BMPs is below the existing flow duration curve. The
flow duration curve table following the curve shows that if the interval 0.1002 - Qio is divided in
100 sub-intervals, then a) the post development divided by pre-development durations are
never larger than 110% (the permit allows up to 110%); and b) there are no more than 10
intervals in the range 101%-110% which would imply an excess over 10% of the length of the
curve (the permit allows less than 10% of excesses measured as 101-110%).
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 City of Encinitas 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 TRWE, not only the range of analysis is clearly depicted (10% of Q2 to Q10) but
also all intermediate flows are shown (02, Q3, 04, Os, Q6, Q, 08 and Q9) in order to demonstrate
compliance at any range Q - Q+1. One of the limitations of both the SWMM and SDHM
models is that the intermediate analysis is not performed (to obtain Qi from i = 2 to 10). IRWE
performed the analysis using the Cunnane Plotting position Method (the preferred method in
the HMP permit) 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 Qi with a
return period "i", from i=2 to 10. The 0 values are also added into the flow-duration plot.
Flow Duration Curve - Martin Residence (POC-1)
0.13
0.12
0.11
0.10
0.09 -
0.08
0.07
Cr
0.05
0.04
0.03
0.02
0.01
0.00
0.001 0.01
Percentage of time exceeded (%)
4G
% Ii— a~
-
Existing
- - - Proposed
- - a -
0.06 1%
-I I
-
--
_
O.1i _T flf f 1
Flow Duration Curve - Martin Residence (POC-1)
0.12
0.10 CIT _._._._.J._..._._._._._._._._._._._._._._._.L_.__._.L._.J.
All 0.08 -
.4- U ._._.%.._._._._
I
.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- -Q2
0.06 Existing
I --- Proposed
QX
0.04
:::
:: _ i.
J11TI::r:J. j::::
T-I
0 0.01 0.02 0.03
Percentage of time exceeded (%)
Flow Duration Curve Data for Martin Residence (POC-1), Carlsbad, CA
Q2 = 0.07 cfs Fraction 10%
Q10 = 012 cis
Step = 0.0012 cfs
Count = 497370 hours
56.74 years
Interval
Existing Condition Detention Optimized Pass or
Fail? Q (cfs) Hours > Q % time Hours>Q % time Post/Pre
1 0.007 134 2.69€-02 108 2.17E-02 81% Pass
2 0.008 131 2.63E-02 106 2.13E-02 81% Pass
3 0.009 130 2.61E-02 104 2.09E-02 80% Pass
4 0.010 129 2.59E-02 101 2.03E-02 78% Pass
5 0.011 125 2.51E-02 100 2.01E-02 80% Pass
6 0.012 123 2.47E-02 96 1.93E-02 78% Pass
7 0.014 122 2.45E-02 95 1.91E-02 78% Pass
8 0.015 120 2.41E-02 84 1.69E-02 70% Pass
9 0.016 120 2.41E-02 84 1.69E-02 70% Pass
10 0.017 118 2.37E-02 61 1.23E-02 52% Pass
11 0.018 117 2.35E-02 57 1.15E-02 49% Pass
12 0.019 112 2.25E-02 55 1.11E-02 49% Pass
13 0.021 105 2.11E-02 55 1.11E-02 52% Pass
14 0.022 105 2.11E-02 50 1.01E-02 48% Pass
15 0.023 102 2.05E-02 50 1.01E-02 49% Pass
16 0.024 97 1.95E-02 49 9.85E-03 51% Pass
17 0.025 96 1.93E-02 49 9.85E-03 51% Pass
18 0.026 96 1.93E-02 49 9.85E-03 51% Pass
19 0.028 93 1.87E-02 47 9.45E-03 51% Pass
20 0.029 92 1.85E-02 47 9.45E-03 51% Pass
21 0.030 89 1.79E-02 43 8.65E-03 48% Pass
22 0.031 85 1.71E-02 42 8.44E-03 49% Pass
23 0.032 84 1.69E-02 41 8.24E-03 49% Pass
24 0.033 84 1.69E-02 40 8.04E-03 48% Pass
25 0.035 83 1.67E-02 38 7.64E-03 46% Pass
26 0.036 83 1.67E-02 36 7.24E-03 43% Pass
27 0.037 81 1.63E-02 25 5.03E-03 31% Pass
28 0.038 71 1.43E-02 24 4.83E-03 34% Pass
29 0.039 58 1.17E-02 24 4.83E-03 41% Pass
30 0.040 58 1.17E-02 24 4.83E-03 41% Pass
31 0.042 57 1.15E-02 24 4.83E-03 42% Pass
32 0.043 57 1.15E-02 24 4.83E-03 42% Pass
33 0.044 57 1.15E-02 24 4.83E-03 42% Pass
34 0.045 53 1.07E-02 21 4.22E-03 40% Pass
35 0.046 53 1.07E-02 21 4.22E-03 40% Pass
36 0.047 51 1.03E-02 21 4.22E-03 41% Pass
37 0.049 51 1.03E-02 21 4.22E-03 41% Pass
Interval
ExistingCondition Detention Optimized Pass or
Fail? Q (cfs) Hours > Q % time Hours>Q % time Post/Pre
38 0.050 51 1.03E-02 21 4.22E-03 41% Pass
39 0.051 51 1.03E-02 20 4.02E-03 39% Pass
40 0.052 50 1.01E-02 19 3.82E-03 38% Pass
41 0.053 48 9.65E-03 18 3.62E-03 38% Pass
42 0.054 48 9.65E-03 17 3.42E-03 35% Pass
43 0.056 43 8.65E-03 17 3.42E-03 40% Pass
44 0.057 43 8.65E-03 17 3.42E-03 40% Pass
45 0.058 41 8.24E-03 17 3.42E-03 41% Pass
46 0.059 36 7.24E-03 16 3.22E-03 44% Pass
47 0.060 36 7.24E-03 16 3.22E-03 44% Pass
48 0.061 36 7.24E-03 16 3.22E-03 44% Pass
49 0.063 35 7.04E-03 16 3.22E-03 46% Pass
50 0.064 34 6.84E-03 16 3.22E-03 47% Pass
51 0.065 33 6.63E-03 16 3.22E-03 48% Pass
52 0.066 32 6.43E-03 15 3.02E-03 47% Pass
53 0.067 32 6.43E-03 15 3.02E-03 47% Pass
54 0.068 32 6.43E-03 14 2.81E-03 44% Pass
55 0.070 32 6.43E-03 13 2.61E-03 41% Pass
56 0.071 32 6.43E-03 13 2.61E-03 41% Pass
57 0.072 31 6.23E-03 13 2.61E-03 42% Pass
58 0.073 31 6.23E-03 11 2.21E-03 35% Pass
59 0.074 30 6.03E-03 10 2.01E-03 33% Pass
60 0.075 28 5.63E-03 10 2.01E-03 36% Pass
61 0.077 27 5.43E-03 10 2.01E-03 37% Pass
62 0.078 26 5.23E-03 10 2.01E-03 38% Pass
63 0.079 26 5.23E-03 10 2.01E-03 38% Pass
64 0.080 21 4.22E-03 10 2.01E-03 48% Pass
65 0.081 21 4.22E-03 10 2.01E-03 48% Pass
66 0.082 21 4.22E-03 10 2.01E-03 48% Pass
67 0.084 20 4.02E-03 10 2.01E-03 50% Pass
68 0.085 19 3.82E-03 10 2.01E-03 53% Pass
69 0.086 18 3.62E-03 10 2.01E-03 56% Pass
70 0.087 18 3.62E-03 10 2.01E-03 56% Pass
71 0.088 18 3.62E-03 10 2.01E-03 56% Pass
72 0.089 18 3.62E-03 10 2.01E-03 56% Pass
73 0.091 18 3.62E-03 10 2.01E-03 56% Pass
74 0.092 18 3.62E-03 8 1.61E-03 44% Pass
75 0.093 17 3.42E-03 7 1.41E-03 41% Pass
76 0.094 16 3.22E-03 7 1.41E-03 44% Pass
77 0.095 16 3.22E-03 7 1.41E-03 44% Pass
78 0.096 16 3.22E-03 7 1.41E-03 44% Pass
79 0.098 16 3.22E-03 7 1.41E-03 44% Pass
80 0.099 15 3.02E-03 7 1.41E-03 47% Pass
81 0.100 12 2.41E-03 7 1.41E-03 58% Pass
82 0.101 12 2.41E-03 7 1.41E-03 58% Pass
Interval
Existing Condition Detention Optimized Pass or
Fail? Q (cfs) Hours > Q % time Hours>Q % time Post/Pre
83 0.102 12 2.41E-03 7 1.41E-03 58% Pass
84 0.103 9 1.81E-03 7 1.41E-03 78% Pass
85 0.105 9 1.81E-03 7 1.41E-03 78% Pass
86 0.106 9 1.81E-03 7 1.41E-03 78% Pass
87 0.107 9 1.81E-03 7 1.41E-03 78% Pass
88 0.108 9 1.81E-03 7 1.41E-03 78% Pass
89 0.109 8 1.61E-03 7 1.41E-03 88% Pass
90 0.110 8 1.61E-03 7 1.41E-03 88% Pass
91 0.112 8 1.61E-03 7 1.41E-03 88% Pass
92 0.113 8 1.61E-03 7 1.41E-03 88% Pass
93 0.114 7 1.41E-03 6 1.21E-03 86% Pass
94 0.115 7 1.41E-03 6 1.21E-03 86% Pass
95 0.116 6 1.21E-03 6 1.21E-03 100% Pass
96 0.117 6 1.21E-03 6 1.21E-03 100% Pass
97 0.119 6 1.21E-03 6 1.21E-03 100% Pass
98 0.120 6 1.21E-03 6 1.21E-03 100% Pass
99 0.121 6 1.21E-03 6 1.21E-03 100% Pass
100 0.122 6 1.21E-03 6 1.21E-03 100% Pass
Peak Flows calculated with Cunnane Plotting Position
Return Period
(years) Pre-dev. Q (cfs) Post-Dev. 0
(cfs)
Reduction
(cfs)
10 0.122 0.110 0.012
9 0.118 0.097 0.021
8 0.114 0.091 0.023
7 0.111 0.091 0.020
6 0.103 0.075 0.028
5 0.100 0.073 0.027
4 0.095 0.067 0.029
3 0.080 0.036 0.044
2 0.065 0.018 0.047
ATTACHMENT 3
List of the "n" largest Peaks: Pre-Development
and Post-Development Conditions
ATTACHMENT 3
List of the "n" Largest Peaks: Pre & Post-Developed Conditions
Basic Probabilistic Equation:
R = 1/P R: Return period (years).
P: Probability of a flow to be equaled or exceeded any given year (dimensionless)
Cunnane Equation: Weibull Equation:
P P=-- n+O.2 n+1
i: Position of the peak whose probability is desired (sorted from large to small)
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 from 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).
List of Peak events and Determination of Q2 and Q10 (Pre-Development)
Martin Residence (POC-1)
T
(Year)
Cunnane
(cfs)
Weibull
(cfs) Peaks (cfs)
Date Posit
Period of Return
(Years)
10 0.12 0.13 Weibull Cunnane
9 0.12 0.12 0.039 12/10/1965 57 1.02 1.01
8 0.11 0.12 0.039 3/8/1968 56 1.04 1.03
7 0.11 0.11 0.039 1/15/1978 55 1.05 1.05
6 0.10 0.10 0.039 1/6/1979 54 .07 - 1.07
5 0.10 0.10 0.039 1/11/1980 53 1.09 1.09
4 0.10 0.10 0.039 11/25/1988 52 1.12 1.11
3 0.08 0.08 0.039 12/24/1988 51 1.14 1.13
2 0.07 0.07 0.041 2/19/1958 50 1.16 1.15
Note:
Cunnane is the preferred
method by the HMP permit.
0.045 12/2/1961 49 1.18 1.18
0.045 2/22/1998 48 1.21 1.20
0.045 11/8/2002 47 1.23 1.23
0.045 2/12/2003 46 1.26 1.25
0.047 11/11/1985 45 1.29 1.28
0.047 12/31/2004 44 1.32 1.31
0.051 3/2/1980 43 1.35 1.34
0.053 1/18/1993 42 1.38 1.38
0.053 2/14/1998 41 1.41 1.41
0.055 2/12/1992 40 1.45 1.44
0.055 2/8/1993 39 1.49 1.48
0.057 3/1/1991 38 1.53 1.52
0.057 12/30/1991 37 1.57 1.56
0.059 1/16/1978 36 1.61 1.61
0.059 1/29/1980 35 1.66 1.65
0.059 2/15/1986 34 1.71 1.70
0.059 3/15/1986 33 1.76 1.75
0.062 3/11/1995 32 1.81 1.81
0.063 1/6/2008 31 1.87 1.87
0.064 1/27/2008 30 1.93 1.93
0.065 2/17/1998 29 2.00 2.00
0.071 2/23/1998 28 2.07 2.07
0.074 12/19/1970 27 2.15 2.15
0.075 1/29/1983 26 2.23 2.23
0.075 10/20/2004 25 2.32 2.33
0.076 2/16/1980 24 2.42 2.42
0.077 11/22/1965 23 2.52 2.53
0.079 2/10/1978 22 2.64 2.65
0.079 2/27/1983 21 2.76 2.78
0.079 2/3/1998 20 2.90 1 2.92
0.08 10/27/2004 19 3.05 3.08
0.084 1/16/1952 18 3.22 3.25
0.085 11/15/1952 17 3.41 3.45
0.092 10/29/2000 16 3.63 3.67
0.094 4/1/1958 15 3.87 3.92
0.099 3/1/1978 14 4.14 4.21
0.099 2/20/1980 13 4.46 4.54
0.099 3/17/1982 12 4.83 4.93
0.103 1/14/1993 11 5.27 5.40
0.103 2/18/2005 10 5.80 5.96
0.109 2/25/1969 9 6.44 6.65
0.113 2/4/1958 8 7.25 7.53
0.116 9/23/1986 7 8.29 8.67
0.123 2/25/2003 6 9.67 10.21
0.15 1/15/1979 5 11.60 12.43
0.151 1/4/1995 4 14.50 15.89
0.177 1/4/1978 3 19.33 22.00
0.178 10/1/1983 2 29.00 35.75
0.198 4/14/2003 1 58.00 95.33
List of Peak events and Determination of Q2 and Q10 (Post-Development)
Martin Residence (POC-1)
(Year)
Cunnane
(cfs)
Weibull
(cfs) Peaks (cfs)
Date Posit
Period of Return
(Years)
10 0.11 0.12 Weibull Cunnane
9 0.10 0.10 0.006 2/4/1958 57 1.02 1.01
8 0.09 0.09 0.006 2/4/1958 56 1.04 1.03
7 0.09 0.09 0.006 2/4/1958 55 1.05 1.05
6 0.08 0.08 0.006 2/4/1958 54 1.07 1.07
5 0.07 0.07 0.006 2/4/1958 53 1.09 1.09
4 0.07 0.07 0.006 2/4/1958 52 1.12 1.11
3 0.04 0.04 0.006 2/4/1958 51 1.14 1.13
2 0.02 0.02 0.006 1/15/1978 50 1.16 1.15
Note:
Cunnane is the preferred
method by the HMP permit.
0.006 1/15/1978 49 1.18 1.18
0.006 1/15/1978 48 1.21 1.20
0.006 1/15/1978 47 1.23 1.23
0.006 1/15/1979 46 1.26 1.25
0.006 1/15/1979 45 1.29 1.28
0.006 1/15/1979 44 1.32 1.31
0.006 1/15/1979 43 1.35 1.34
0.006 1/15/1979 42 1.38 1.38
0.006 1/15/1979 41 1.41 1.41
0.006 3/2/1983 40 1.45 1.44
0.006 3/2/1983 39 1.49 1.48
0.006 10/27/2004 38 1.53 1.52
0.006 10/27/2004 37 1.57 1.56
0.006 10/27/2004 36 1.61 1.61
0.006 10/27/2004 35 1.66 1.65
0.006 10/27/2004 34 1.71 1.70
0.006 10/27/2004 33 1.76 1.75
0.01 2/23/1998 32 1.81 1.81
0.013 12/5/1966 31 1.87 1.87
0.018 1/4/1978 30 1.93 1.93
0.018 1/12/1980 29 2.00 2.00
0.018 1/12/1980 28 2.07 2.07
0.023 1/25/1969 27 2.15 2.15
0.034 11/22/1965 26 2.23 2.23
0.035 2/15/1986 25 2.32 2.33
0.035 2/22/2008 24 2.42 2.42
0.036 1/18/1952 23 2.52 2.53
0.036 1/11/1980 22 2.64 2.65
0.036 1/11/1980 21 2.76 2.78
0.036 1/11/1980 20 2.90 2.92
0.036 2/18/1980 19 3.05 3.08
0.044 1/18/1993 18 3.22 3.25
0.05 11/22/1996 17 3.41 3.45
0.054 3/3/1983 16 3.63 3.67
0.066 1/16/1993 15 3.87 3.92
0.068 3/8/1968 14 4.14 4.21
0.069 1/9/2005 13 4.46 4.54
0.073 1/6/1979 12 4.83 4.93
0.073 2/23/2005 11 5.27 5.40
0.074 1/11/2005 10 5.80 5.96
0.091 1/29/1980 9 6.44 6.65
0.091 3/1/1991 8 7.25 7.53
0.092 1/16/1978 7 8.29 8.67
0.113 3/17/1982 6 9.67 10.21
0.129 3/1/1978 5 11.60 12.43
0.129 2/20/1980 4 14.50 15.89
0.139 2/25/1969 3 19.33 22.00
0.177 1/4/1995 2 29.00 35.75
0.221 4/14/2003 1 58.00 95.33
ATTACHMENT 4
Elevation vs. Area Curves and Elevation vs. Discharge Curves
to be used in SWMM
ATTACHMENT 4
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 for 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 orifice sizes have been selected to maximize their size while still restricting flows to
conform with the required 10% of the 02 event flow as mandated in the Final
Hydromodification Management Plan by Brown & Caldwell, dated March 2011. While TRWE
acknowledges that these orifices are 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 orifices, regular maintenance of the riser
and orifices must be performed to ensure potential blockages are minimized. A detail of the
orifice and riser structures is provided in Attachment 5 of this memorandum.
DISCHARGE EQUATIONS
Weir:
Qw= Cw LH3''2 (1)
Slot:
As an orifice: Q5 = B5 h5 c9 \J2g (H
-
(2.a)
As a weir: Q = C, B H312 (2.b)
For H > h5 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: Q0 = 0.25 . irD2 c9 j2g (H
-
(3.a)
As a weir: Critical depth and geometric family of circular sector must be solved to determined 0 as a function of
H:
Q02 A
- - -
Acr Tcr = 2Jy(D - Ycr) Acr = [acr - sin(acr)]; - p H=y
9 T. 2 + ' T
Ycr =
D [1 - sin(0.5 a)] (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:
Q, Os, Qo = Discharge of weir, slot or orifice (cfs)
Cw, C9 : Coefficients of discharge of weir (typically 3.1) and orifice (0.61 to 0.62)
L, B, 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 (ft2), top width (ft), critical depth (ft), and angle to the center,
respectively.
Stage-Storage for Underground Storage 1-1
Facility Type: Vault
0.00
4.00
Outlet structure for Discharge of DMA 1-1
Discharge vs Elevation Table
Low orifice 0.3125 Lower slot Lower Weir
Number of orif: 1 Number of slots: 0 Number of weirs: 0
Cg-low: 0.62 Invert: 3.75 ft Invert: 3.63
B 0.02 ft B: 0.50
Middle orifice 0.250 h510 0.021 ft
Number of orif: 1
Cg-middle: 0.62 Upper slot Emergency weir
invert elev: 3.500 ft Number of slots: 0 Invert: 3.75 ft
Invert: 0.00 ft B: 4.00 ft
*Note. h = head above the invert of the B: 0.00 ft
lowest surface discharge opening. ~jot 0.083 ft
h*
(ft)
H/D-tow
-
H/D-mid
-
Qiow-orif
(cfs)
Qiow-weir
(cfs)
Qtot-low
(cfs)
Qmid-orif
(cfs)
Qmid-weir
(cfs)
Qtot-med
(cfs)
Qslot-low
(cfs)
Qslot-upp
(cfs)
Qweir
(cfs)
Qemerg
(cfs)
Qtot
(cfs)
0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
0.042 1.600 0.000 0.000 0.001 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
0.083 3.200 0.000 0.001 1 0.001 0.001 1 0.000 0.000 0.000 0.000 0.000 0.000 1 0.000 0.001
0.125 4.800 0.000 0.001 0.004 0.001 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.001
0.167 6.400 0.000 0.001 0.010 0.001 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.001
0.208 8.000 0.000 0.001 0.012 0.001 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.001
0.250 9.600 0.000 0.001 0.013 0.001 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.001
0.292 11.200 0.000 0.001 0.014 0.001 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.001
0.333 12.800 0.000 0.001 0.015 0.001 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.001
0.375 14.400 0.000 0.002 0.016 0.002 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.002
0.417 16.000 0.000 0.002 0.017 0.002 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.002
0.458 17.600 0.000 0.002 0.018 0.002 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.002
0.500 19.200 0.000 0.002 0.018 0.002 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.002
0.542 20.800 0.000 0.002 0.019 0.002 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.002
0.583 22.400 0.000 0.002 0.020 0.002 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.002
0.625 24.000 0.000 0.002 0.021 0.002 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.002
0.667 25.600 0.000 0.002 0.021 0.002 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.002
0.708 1 27.200 0.000 0.002 0.022 0.002 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.002
0.750 28.800 0.000 0.002 0.023 0.002 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.002
0.792 30.400 0.000 0.002 0.023 0.002 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.002
0.833 32.000 0.000 0.002 0.024 0.002 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.002
0.875 33.600 0.000 0.002 0.025 0.002 0.000 0.000 0.000 0.000 0.000 1 0.000 0.000 0.002
0.917 1 35.200 0.000 0.003 0.025 0.003 0.000 0.000 0.000 0.000 0.000 1 0.000 0.000 0.003
h* H/D-low H/D-mid Qiow-orif
(cfs)
Qiow-weir
(cfs)
Qtot-IOW
(cfs)
Qmid-orif
(cfs)
Qmld-weir
(cfs)
Qtot-med
(cfs)
Qslot-low
(cfs)
Qslot-upp
(cfs)
Qweir
(cfs)
Qemerg
(cfs)
Qtot
(cfs)
0.958 36.800 0.000 0.003 0.026 0.003 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.003
1.000 38.400 0.000 0.003 0.026 0.003 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.003
1.042 1 40.000 0.000 0.003 1 0.027 0.003 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.003
1.083 41.600 0.000 0.003 0.027 0.003 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.003
1.125 43.200 0.000 0.003 0.028 0.003 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.003
1.167 44.800 0.000 0.003 0.028 0.003 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.003
1.208 46.400 0.000 0.003 0.029 0.003 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.003
1.250 48.000 0.000 0.003 1 0.029 0.003 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.003
1.292 49.600 0.000 0.003 0.030 0.003 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.003
1.333 51.200 0.000 0.003 0.030 0.003 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.003
1.375 52.800 0.000 0.003 0.031 0.003 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.003
1.417 54.400 0.000 0.003 0.031 0.003 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.003
1.458 56.000 0.000 0.003 0.032 0.003 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.003
1.500 57.600 0.000 0.003 0.032 0.003 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.003
1.542 59.200 0.000 0.003 0.033 0.003 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.003
1.583 60.800 0.000 0.003 0.033 0.003 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.003
1.625 62.400 0.000 0.003 0.034 0.003 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.003
1.667 64.000 0.000 0.003 0.034 0.003 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.003
1.708 65.600 0.000 0.003 0.035 0.003 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.003
1.750 67.200 0.000 0.003 0.035 0.003 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.003
1.792 68.800 0.000 0.004 0.035 0.004 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.004
1.833 70.400 0.000 0.004 0.036 0.004 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.004
1.875 72.000 0.000 0.004 0.036 0.004 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.004
1.917 73.600 0.000 0.004 0.037 0.004 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.004
1.958 75.200 0.000 0.004 0.037 0.004 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.004
2.000 76.800 0.000 0.004 0.037 0.004 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.004
2.042 78.400 0.000 0.004 0.038 0.004 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.004
2.083 80.000 0.000 0.004 0.038 0.004 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.004
2.125 81.600 0.000 0.004 0.039 0.004 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.004
2.167 83.200 0.000 0.004 0.039 0.004 0.000 0.000 0.000 0.000 1 0.000 0.000 0.000 0.004
2.208 84.800 0.000 0.004 0.039 0.004 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.004
2.250 86.400 0.000 0.004 0.040 0.004 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.004
2.292 88.000 0.000 0.004 0.040 0.004 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.004
2.333 89.600 0.000 0.004 0.040 0.004 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.004
2.375 91.200 0.000 0.004 0.041 0.004 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.004
2.417 92.800 0.000 0.004 0.041 0.004 0.000 0.000 0.000 0.000 0.000
1
0.000 0.000 0.004
2.458 94.400 0.000 0.004 0.041 0.004 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.004
ht
(ft)
H/D-low
-
H/D-mid
-
Qiow-orif
(cfs)
Qiow-weir
(cfs)
Qtot-low
(cfs)
Qmid-orif
(cfs)
Qmid-weir
(cfs)
Qtot-med
(cfs)
Qslot-low
(cfs)
Qslot-upp
(cfs)
Qweir
(cfs)
Qemerg
(cfs)
Qtot
(cfs)
2.500 96.000 0.000 0.004 0.042 0.004 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.004
2.542 97.600 0.000 0.004 0.042 0.004 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.004
2.583 99.200 0.000 0.004 1 0.042 0.004 0.000 0.000 0.000 0.000 0.000 0.000 1 0.000 0.004
2.625 100.800 0.000 0.004 0.043 0.004 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.004
2.667 102.400 0.000 0.004 0.043 0.004 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.004
2.708 104.000 0.000 0.004 0.044 0.004 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.004
2.750 105.600 0.000 0.004 0.044 0.004 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.004
2.792 107.200 0.000 0.004 0.044 0.004 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.004
2.833 108.800 0.000 0.004 0.045 0.004 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.004
2.875 110.400 0.000 0.004 0.045 0.004 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.004
2.917 112.000 0.000 0.005 0.045 0.005 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.005
2.958 113.600 0.000 0.005 0.045 0.005 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.005
3.000 115.200 0.000 0.005 0.046 0.005 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.005
3.042 116.800 0.000 0.005 0.046 0.005 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.005
3.083 118.400 0.000 0.005 0.046 0.005 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.005
3.125 120.000 0.000 0.005 0.047 0.005 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.005
3.167 121.600 0.000 0.005 0.047 0.005 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.005
3.208 123.200 0.000 0.005 0.047 0.005 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.005
3.250 124.800 0.000 0.005 0.048 0.005 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.005
3.292 126.400 0.000 0.005 0.048 0.005 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.005
3.333 128.000 0.000 0.005 0.048 0.005 1 0.000 0.000 0.000 0.000 0.000 1 0.000 0.000 0.005
3.375 129.600 0.000 0.005 0.049 0.005 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.005
3.417 131.200 0.000 0.005 0.049 0.005 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.005
3.458 132.800 0.000 0.005 0.049 0.005 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.005
3.500 134.400 0.000 0.005 0.049 0.005 0.000 0.000 0.000 0.000 0.000 0.000 1 0.000 0.005
3.542 136.000 2.000 0.005 0.050 0.005 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.005
_3.583 137.600 4.000 0.005 0.050 0.005 0.000 0.001 0.000 0.000 0.000 0.000 0.000 0.005
3.625 139.200 6.000 0.005 0.050 0.005 0.001 0.011 0.001 0.000 0.000 0.000 0.000 0.006
3.667 140.800 8.000 0.005 0.051 0.005 0.001 0.070 0.001 0.000 0.000 0.000 0.000 0.006
3.708 142.400 10.000 0.005 0.051 0.005 0.001 0.268 0.001 0.000 0.000 0.000 0.000 0.006
3.750 144.000 12.000 0.005 0.051 0.005 0.001 0.761 0.001 0.000 0.000 0.000 0.000 0.006
3.792 145.600 14.000 0.005 0.052 0.005 0.001 1.795 0.001 0.000 0.000 0.000 0.105 0.112
3.833 147.200 16.000 0.005 0.052 0.005 0.001 3.723 0.001 0.000 0.000 0.000 0.298 0.304
3.875 148.800 18.000 0.005 0.052 0.005 0.001 7.022 0.001 0.000 0.000 0.000 0.548 0.554
3.917 150.400 20.000 0.005 0.052 0.005 0.001 12.318 0.001 0.000 0.000 0.000 0.844 0.850
3.958 152.000 22.000 0.005 0.053 0.005 0.001 20.398 0.001 0.000 0.000 0.000 1.179 1.186
4.000 153.600 24.000 0.005 0.053 0.005 0.001 32.236 0.001 0.000 0.000 0.000 1.550 1.556
TORY R.WALKER ENGINEERING
RELIABLE SOLUTIONS IN WATER RESOURCES
Project Name Martin Residence
Project No 439-01
Date ....................... .3/1/2017
Drawdown Calculation for IMP 1
I Total Drawdown Time: 140.8 hours I Note: Though drowdown time exceeds the 96 hour
requirement for vector control, a vector control plan is
not recommended, as the detention system is entirely
underground, and is not susceptible to typical vector
control issues.
Surface Depth (ft) Volume (cu-ft) Q,jce (cfs) AT (hr) Total lime (hr)
4.00 1340 1.556 0.000 0.0
3.96 1326 1.186 0.003 0.0
3.92 1312 0.850 0.004 0.0
3.87 1298 0.554 0.006 0.0
3.83 1284 0.304 0.009 0.0
3.79 1270 0.112 0.019 0.0
3.75 1256 0.006 0.066 0.1
3.71 1242 0.006 0.657 0.8
3.67 1228 0.006 0.669 1.4
3.63 1214 0.006 0.683 2.1
3.58 1200 0.005 0.700 2.8
3.54 1186 0.005 0.722 3.5
3.50 1173 0.005 0.758 4.3
3.46 1159 0.005 0.786 5.1
3.42 1145 0.005 0.791 5.9
3.38 1131 0.005 0.795 6.7
3.33 1117 0.005 0.800 7.5
3.29 1103 0.005 0.805 8.3
3.25 1089 0.005 0.811 9.1
3.21 1075 0.005 0.816 9.9
3.17 1061 0.005 0.821 10.7
3.13 1047 0.005 0.827 11.5
3.08 1033 0.005 0.832 12.4
3.04 1019 0.005 0.838 13.2
3.00 1005 0,005 0.844 14.1
2.96 991 0.005 0.850 14.9
2.92 977 0.005 0.856 15.8
2.88 963 0.004 0.862 16.6
2.83 949 0.004 0.868 17.5
2.79 935 0.004 0.874 18.4
2.75 921 0.004 0.881 19.3
2.71 907 0.004 0.888 20.1
2.67 893 0.004 0.895 21.0
2.63 879 0.004 0.902 21.9
2.58 865 0.004 0.909 22.8
2.54 851 0.004 0.916 23.8
2.50 838 0.004 0.924 24.7
2.46 824 0.004 0.932 25.6
2.42 810 0.004 0.940 26.6
2.38 796 0.004 0.948 27.5
2.33 782 0.004 0.956 28.5
2.29 768 0.004 0.965 29.4
2.25 754 0.004 0.974 30.4
2.21 740 0.004 0.983 31.4
2.17 726 0.004 0.992 32.4
2.13 712 0.004 1.002 33.4
2.08 698 0.004 1.012 34.4
2.04 684 0.004 1.022 35.4
2.00 670 0.004 1.033 36.4
Surface Depth (ft) Volume (cu-ft) Qfice (cfs) AT (hr) Total Time (hr)
1.96 656 0.004 1.043 37.5
1.92 642 0.004 1.055 38.5
1.88 628 0.004 1.066 39.6
1.83 614 0.004 1.078 40.7
1.79 600 0.004 1.091 41.8
1.75 586 0.003 1.104 42.9
1.71 572 0.003 1.117 44.0
1.67 558 0.003 1.131 45.1
1.63 544 0.003 1.145 46.3
1.58 530 0.003 1.160 47.4
1.54 516 0.003 1.175 48.6
1.50 503 0.003 1.192 49.8
1.46 489 0.003 1.208 51.0
1.42 475 0.003 1.226 52.2
1.38 461 0.003 1.244 53.5
1.33 447 0.003 1.263 54.7
1.29 433 0.003 1.284 56.0
1.25 419 0.003 1.305 57.3
1.21 405 0.003 1.327 58.7
1.17 391 0.003 1.350 60.0
1.13 377 0.003 1.375 61.4
1.08 363 0.003 1.401 62.8
1.04 349 0.003 1.428 64.2
1.00 335 0.003 1.457 65.7
0.96 321 0.003 1.489 67.2
0.92 307 0.003 1.522 68.7
0.88 293 0.002 1.557 70.2
0.83 279 0.002 1.595 71.8
0.79 265 0.002 1.636 73.5
0.75 251 0.002 1.681 75.1
0.71 237 0.002 1.729 76.9
0.67 223 0.002 1.782 78.7
0.63 209 0.002 1.839 80.5
0.58 195 0.002 1.903 82.4
0.54 181 0.002 1.974 84.4
0.50 168 0.002 2.054 86.4
0.46 154 0.002 2.143 88.6
0.42 140 0.002 2.246 1 90.8
0.38 126 0.002 2.366 93.2
0.33 112 0.001 2.506 95.7
0.29 98 0.001 2.675 98.4
0.25 84 0.001 2.884 101.2
0.21 70 0.001 3.151 104.4
0.17 56 0.001 3.509 107.9
0.13 42 0.001 4.027 111.9
0.08 28 0.001 4.879 116.8
0.041 14 0.000 6.736 123.5
0.001 0 0.000 17.289 140.8
ATTACHMENT 5
Point of Compliance Exhibit, Existing and Developed DMA Maps,
Project Plan and Detention Section Sketches
Martin Residence Project Site
Project Vicinity Map N
Martin Residence A
Carlsbad, California 1 in = 750 ft
&I
Adams St
1*0
Ie.m.
•-•]-:_
&
Existing Condition
DMA Map
Martin Residence
A
1 in = 25 ft
54 SF PERVIOUS
DMA ii
DRAINS TO IMP 1
616 SF
100% IMPERVIOUS
DMA 2
DRAINS TO IMP 2
535 SF
IMP
100% IMPERVIOUS
BIOFIL TRA TION BASIN
21 SF
IMP 1
B/OF/I IRA TION BASIN
44 SF
DMA 3
DRAINS TO IMP 3
1,483 SF
1,373 SF IMPERVIOUS
110 SF PER VIOUS
BIOFIL IRA TION BASIN
55 SF
SELF RETAINING
501 SF
BY-PASS 1-1
0.0006 Acres (28 SF)
Poc-1 I/I
DIVA /
SELF MITIGATING /
7,887 SF
/
/
7
IMP 5
BIOFIL TRA RON BASIN
38 SF
IMP 4
BIOFIL IRA TION BASIN
DMA 4 126 SF DMA 5 DMA 6
DRAINS TO IMP 4 SELF MITIGATING DRAINS TO IMP 5 DMA 5 3,732 SF 277 SF 1,086 SF
1007. /MPERWOUS 1007. IMPERVIOUS
x< Awk
CO
4332
I' I
7/ J
DMA)f /1
I
N. T. S.
DMA 1-1 Imp (f) Pen, (f) Total (f)
DMA 1 616 0 616
IMP 0 44 44
DMA 535 0 535
IMP 0 21 21
DMA 3 1373 110 1483
IMP 0 55 55
DMA 2769 963 3732
IMP 0 126 126
DMA 5 0 277 277
IMPS 0 38 38
DMA 1086 0 1086
POOL EQUIP 0 54 54
Total 6379 1688 8067
10. 1852 Ad
ii
-TRWE
Proposed Condition
DMA Map
Martin Residence
SLE 9E 1 9 SE I SZO X T 00 SZIE0 X
(Id)H (NO za I (NO Ia (IM n]1] vivia/# UJ) A313 vivia/# A1flDV
9VUO1S thJM MO1d1JAO ]DLJIUO 310GIVY JDkIIUO 113M01
37Y7S 01 ION
(VOL 03S - 71V13C 77VM 8/344
.L71WA 01
N. . .. - p . .. . •... .'• .
7V1HDll8YM
:•.
L/0 3O7
YO07d17f?M
0
A373
37CC/fl'
H
)
77VM 17/WA
01 1708
371J/80 37CC/#Y
/3H M07i80
37V9S 0.1 ION
7/VI3CI 7/71721
13flO 17/WA 1
(iL V7S 7VL3Y C3Z/NYA 7YD)
p /77Y41L//3$4
(77YM 30 aol) bum
T07T
17/WA 313YONOO
ATTACHMENT 6
SWMM Input Data in Input Format
(Existing & Proposed Models)
Pre-Dev Input (POc-1)
[TITLE]
;Project Title/Notes
439-01 Martin Residence- Pre Development condition Model
[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
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 0.030 0.050 0.080 0.110 0.130 0.150 0.150 0.130 0.110 0.080 0.040 0.020
SWMM 5.1 Page 1
Pre-Dev Input (Poc-1)
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_i OCEANSIDE POC-i 0.197 0 69 25 0
[SUBAREAS]
;;Subcatchment N-Impery N-Pery S-Impery S-Pery PctZero RouteTo PctRouted
,,
DMA_i 0.012 .06 0.05 0.1 25 OUTLET
[INFILTRATION]
;;Subcatchment Suction Ksat IMD
DMA_i 3 0.2 0.32
[OUTFALLS]
;;Name Elevation Type Stage Data Gated Route To
,,
POC-1 0 FREE NO
[TIMEsERIES]
;;Name Date Time Value
OCEANSIDE FILE "X:\ENGR\HMP\Rain Gages\Oceanside\Oside_HOURLY.prn"
[REPORT]
;;Reporting Options
INPUT NO
CONTROLS NO
SUBCATCHMENTS ALL
NODES ALL
LINKS ALL
[TAGS]
[MAP]
DIMENSIONS 2182.681359 6021.851375 2183.279716 6040.229030
Units Degrees
SWMM 5.1 Page 2
Pre-Dev Input (POC-1)
[COORDINATES]
Node
C-1
[VERTICES]
;Link
, ,
[Polygons]
;subcatchment
,,
DMA_i
[SYMBOLS]
;Gage
,,
OCEANSIDE
X-Coord Y-Coord
2182.903000 6028.978143
X-Coord Y-Coord
X-Coord Y-Coord
2182.902773 6036.961572
X-Coord Y-Coord
2182.903000 6039.000000
SWMM 5.1 Page 3
Post-Dev Input (Poc-1)
[TITLE]
;Project Title/Notes
439-01 Martin Residence- Post Development condition Model
[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
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 0.030 0.050 0.080 0.110 0.130 0.150 0.150 0.130 0.110 0.080 0.040 0.020
SWMM 5.1 Page 1
Post-Dev Input (POC-1)
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_i-i OCEANSIDE STOR_1-1 .1852 79.1 504 15 0
BY-PASS-1-1 OCEANSIDE POC-i .0006 100 4 0 0
[SUBAREAS]
;;subcatchment N-Impery N-Pery S-Impery S-Pery PctZero RouteTo PctRouted
DMA_i-i 0.012 .08 0.05 0.1 25 OUTLET
BY-PASS-1-1 0.012 .08 0.05 0.1 25 OUTLET
[INFILTRATION]
;;Subcatchment Suction Ksat IMD
DMA_i-i 9 .01875 0.3
BY-PASS-1-1 9 .01875 0.3
[OUTFALLS]
;;Name Elevation Type Stage Data Gated Route To
POC-1 0 FREE NO
[STORAGE]
;;Name Elev. MaxDepth InitDepth Shape Curve Name/Params N/A Fevap Psi
Ksat IMD
,,
STOR_1-1 0 4 0 TABULAR SURF-1 0 0
[OUTLETS]
;;Name From Node To Node Offset Type QTable/Qcoeff Qexpon Gated
i STOR_1-1 POC-1 0 TABULAR/DEPTH OUT-1 NO
[CURVES]
;;Name Type x-value Y-Value
,,
SWMM 5.1 Page 2
Post-Dev Input (POc-1)
OUT-1 Rating 0.000 0.000
OUT-1 0.042 0.001
OUT-1 0.083 0.001
OUT-1 0.125 0.001
OUT-1 0.167 0.001
OUT-1 0.208 0.001
OUT-1 0.250 0.001
OUT-1 0.292 0.001
OUT-1 0.333 0.001
OUT-1 0.375 0.002
OUT-1 0.417 0.002
OUT-1 0.458 0.002
OUT-1 0.500 0.002
OUT-1 0.542 0.002
OUT-1 0.583 0.002
OUT-1 0.625 0.002
OUT-1 0.667 0.002
OUT-1 0.708 0.002
OUT-1 0.750 0.002
OUT-1 0.792 0.002
OUT-1 0.833 0.002
OUT-1 0.875 0.002
OUT-1 0.917 0.003
OUT-1 0.958 0.003
OUT-1 1.000 0.003
OUT-1 1.042 0.003
OUT-1 1.083 0.003
OUT-1 1.125 0.003
OUT-1 1.167 0.003
OUT-1 1.208 0.003
OUT-1 1.250 0.003
OUT-1 1.292 0.003
OUT-1 1.333 0.003
OUT-1 1.375 0.003
OUT-1 1.417 0.003
OUT-1 1.458 0.003
OUT-1 1.500 0.003
OUT-1 1.542 0.003
OUT-1 1.583 0.003
OUT-1 1.625 0.003
OUT-1 1.667 0.003
OUT_i 1.708 0.003
OUT-1 1.750 0.003
OUT-1 1.792 0.004
OUT-1 1.833 0.004
SWMM 5.1 Page 3
Post-Dev Input (poc-1)
OUT-1 1.875 0.004
OUT-1 1.917 0.004
OUT-1 1.958 0.004
OUT-1 2.000 0.004
OUT-1 2.042 0.004
OUT-1 2.083 0.004
OUT-1 2.125 0.004
OUT-1 2.167 0.004
OUT-1 2.208 0.004
OUT-1 2.250 0.004
OUT-1 2.292 0.004
OUT-1 2.333 0.004
OUT-1 2.375 0.004
OUT-1 2.417 0.004
OUT-1 2.458 0.004
OUT-1 2.500 0.004
OUT-1 2.542 0.004
OUT-1 2.583 0.004
OUT-1 2.625 0.004
OUT-1 2.667 0.004
OUT-1 2.708 0.004
OUT-1 2.750 0.004
OUT-1 2.792 0.004
OUT-1 2.833 0.004
OUT-1 2.875 0.004
OUT-1 2.917 0.005
OUT-1 2.958 0.005
OUT-1 3.000 0.005
OUT-1 3.042 0.005
OUT-1 3.083 0.005
OUT-1 3.125 0.005
OUT-1 3.167 0.005
OUT-1 3.208 0.005
OUT-1 3.250 0.005
OUT-1 3.292 0.005
OUT-1 3.333 0.006
OUT-1 3.375 0.006
OUT-1 3.417 0.006
OUT-1 3.458 0.006
OUT-1 3.500 0.006
OUT-1 3.542 0.006
OUT-1 3.583 0.006
OUT-1 3.625 0.006
OUT-1 3.667 0.006
OUT-1 3.708 0.006
SWMM 5.1 Page 4
Post-Dev Input (Poc-1)
OUT-1 3.750 0.006
OUT-1 3.792 0.112
OUT-1 3.833 0.305
OUT-1 3.875 0.555
OUT-1 3.917 0.850
OUT-1 3.958 1.186
4.000 1.557
SURF-1 Storage 0 325
SURF-1 4 325
[TIMESERIES]
;;Name Date Time Value
OCEANSIDE FILE "x:\ENGR\HMP\Rain Gages\Oceanside\Oside_HOURLY. pm"
[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-i 597.451 5027.622
STOR_1-1 597.451 5362.131
[VERTICES]
;;Link X-Coord Y-Coord
[Polygons]
;;Subcatchment X-coord y-Coord
DMA_i-i 597.451 5525.460
DMA-1-1 597.451 5525.460
SWMM 5.1 Page 5
Post-Dev Input (Poc-1)
BY-PASS-1-1 749.786 5362.131
BY-PASS-1-1 749.786 5362.131
BY-PASS-1-1 749.786 5362.131
BY-PASS-1-1 749.786 5362.131
BY-PASS-1-1 749.786 5362.131
[SYMBOLS]
;;Gage X-Coord Y-Coord
OCEANSIDE 597.451 5629.110
SWMM 5.1 Page 6
ATTACHMENT 7
SWMM Screens and Explanation of Significant Variables
ATTACHMENT
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 Soil Survey.
Some values incorporated within the SWMM model have been determined from the
professional experience of TRWE 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.
PRE-DEVELOPED CONDITION (POC-1)
SWMM 5.1 - PREDEV_P0C-1np - iStdy Area Map
File Edit View Eroject Report loots findow Help x] -
Project Map
4Titie/Notes
Options
Climatology
Hydrology
Hydraulics OCEANSIDE
Quality
Curves
Time Series
Time Patterns DMA_i
Map Labels I
439-01 Martin Residence- Pre
Development Condition Model
Auto-Length: Off Offsets: Depth j Flow Units: CFS
-
L7 I
Zoom Level 100% 1 X,V: 2112540962, 6043130165 dog
Rain Gage OCEANSIDE
Property IValue
Name OCEANSIDE
X-Coordinate 2182903
V-Coordinate 6039000
Description
Tag
Rain Format INTENSITY
Time Interval 1:00
Snow Catch Fa1.0
Data Source JMESERIES
TIME SERIES-
Series NamOCEANSIDE
DATA FILE:
File
- Station ID
- Rain Units IN
Name of rainfall data file
Outfall POC-1
liProperty 1tt
Name POC1
X-C oordinate 1218203
V-CoordinateJ2&978
Description f
Tag
Inflows NO
Treatment NO
Invert El. 0
Tide Gate NO
Route To
Type FREE
Fixed Outfall -
Fixed _Stage
,
j]
Tidal Outfall
Curve Name
Time Series Ou
Series
User-assigned name of outfall
Subcatchrnent DMA-1 []
Property Value
Name DMA-1
X-Coordinatel218223
V-Coordinate f636-%2
Description
Tag
Rain Gage JOCEANSIDE
Outlet PO C-1
Area 0.197
Width 69
- --------
% Slope 125
%Impery 0
N-Impery 0.012
N-Pen, .06
Dstore-ImpervT0.D5
Dstore-Pery 0.1
%Zero-ImperI25
Subarea Routin OUTLET
Percent RoutealOC
Infiltration JREEN_AMPT
Groundwater NO
Snow Pack
LID Controls 0
Land Uses 0
Initial Buildup NONE
Curb Length 0
Mannings N for pervious area
Infiltration Editor I_______
Infiltration Method f GREEN_AMPT I
Property I Value
Suction Head
Conductivity
Initial Deficit
POST-DEVELOPED CONDITION (POC-1)
SWMMS.1-POSTj)EV_POCWnp- [Study Area Map] -- - - ' 4t 13
File Edit View Project Report lools Window Help
Q 0 V 0 Fai ti T
Project Map i
iTitlefNotes} OCEANSIDE
Options
Climatology
Hydrology
Hydraulics DMA 1-1 Quality -
D. Curves
Time Series
Time Patterns
Map Labels
STOR_i-1 BY-PASS 1-1
U
439-01 Martin Residence- Post
Development Condition Model
Auto-Length: Off Offsetv Depth Flow Unitsr CFS Zoom Level: 100% 1 XV: 283.088, 5115.110
Rain Gage OCEANSIDE
Property Value
NameName OCEANSIDE
X-Coordinate 597.4.51
V-Coordinate 5629110
Description!
Tag
Rain Format INTENSITY
Time Interva 100
Snow Catch Fa 1.0
Data Source
,
JTIMESERIES
TIME SERIES:-
Series N!~:e[OCEANSIDE
DATA FILE:
- File Name
- Station ID *
- Rain Units IN
User-assigned name of rain gage
Outfall POC-1
IPropey 1vtte H
Name IPOC-1
1597.451
V-CoordinateJO27.622
Description
Tag
Inflows NO
Treatment NO
Invert El. 0
NO Tide Gate
Route To
Type FREE
Fixed Outfall
Fixed StaglTO
Tidal Outfall
Curve Nam]
Time Series Ou
Series
User-assigned name of outfall
Subcatchment DMA-1-1
I Property
Name DMA_i-i
X-Coordinate
V-Coordirate
4
5525460,
Description I
-
Tag
OCEANSIDE Rain Gage
Outlet TSTORII
Area .1852
Width 504
%Slope 15
% Impery 79.1
N-Impery 0.012
N-Pery 08
Dstore-ImpervJ0.05
Dstore-Pery 0.1
%Zero-Impery 25
OUTLET Subarea Routin
Percent Routei00
Infiltration GREEN_AMPT
Groundwater NO
Snow Pack
LID Control's 0
Land Uses 0
Initial Buildup NONE
Curb Length 0
User-assigned name of subcatchment
Subcatchment BY-PASS-1-1
Property Value
Name ::BY-PASS 1-1
1749.786
V-Coordinate inatJ362.131
Description
Tag
OCEANSIDE Rain Gage
Outlet POC-1
Area .0006
Width 4
% Slope io
-
N-Impery 0.012
-
N-Pery 08
.05 Dstore-Imperv10
Dstore-Pery Jo.i
%Zero-Impe25
Subarea Routin OUTLET
Percent RouteJ100
Infiltration. GREEN_AMPT
Groundwater NO
Snow Pack
LID Controls 0
Land Uses 0
Initial Buildup NONE
Curb Length 10
User-assigned name of subcatchment
Infiltration Editor I 23J Infiltration Editor
Infiltration Method REEN_AMPT I
Property lValue
Suction Head
Conductivity
j:gl
j0.01875
Initial Deficit j03
Infiltration Method GREEN_AMPT
Property IValue
Suction Head i
0,025 Conductivity
Initial Deficit 103
EXPLANATION OF SELECTED VARIABLES
Sub Catchment Areas:
Please refer to the attached diagrams that indicate the DMA and biofiltration BMP sub-areas modeled
within the project site at both the pre and post developed conditions draining to the POC.
Parameters for the pre-developed model include soils type 0 as determined from the NRCS Web Soil
Survey (see Attachment 8). Suction head, conductivity and initial deficit correspond to average values
expected for this soil type, according to the Model BMP Design Manual San Diego Region (BMPDM).
Type D soil has been assumed in post-developed conditions to account for the anticipated fill soils
onsite, as required by the BMPDM.
In the pre-developed condition, the pervious overland flow roughness value (N-perv) was selected to
reflect the predominantly barren pervious surface (up to a height of 0.1 feet), which includes surfaces
currently covered by existing impervious surfaces (which are assumed not to exist under the 2013 MS4
Permit), as documented in the existing conditions DMA exhibit. Existing vegetation is highly sparse and
areas currently covered by existing impervious surfaces are barren; therefore, to provide documentation
consistent with Table G.1-4 of the BMP Design Manual, we referenced Colorado State University's
"Influence of Simplifications in Watershed Geometry in Simulation of Surface Runoff" (Lane, Woolhiser,
and Yevjevich, 1975) to assign a conservative value of 0.06 to represent a sparsely vegetated surface
(ranges from 0.053 to 0.13), although the site is predominantly bare soil (ranges from 0.012 to 0.033). In
the post-developed condition, the pervious overland flow roughness value was selected to reflect the
pervious vegetated surfaces typical of urban residential landscaped features, such as grass lawns (turf)
and mulch layers for other landscaped areas. Therefore, the conservative BMPDM default value of 0.15
was assigned.
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 than the precise routing in a system where the time of concentration is
much smaller than 1 hour.
Storage Vault and Discharge for STOR_1-1
Storage Unit STOR_1-1
Property Value H
Name :::STORi-1
X-Coordinate 597.451
V-Coordinate 5362.131
Description
Tag
Inflows NO
Treatment NO
Invert El. 0
Max.. Depth 4
Initial'. Depth 10
Ponded ArjO
Evap. Factor
Seepage Loss NO
Storage Curve JTABULAR
Functional Cur
Coefficient 1000
Exponent Exponent T0
Constant
Tabular Curve
Curve Name
User-assigned name of storage unit
Storage Curve Editor
Curve Name
SURF-1
Description
view... 1
Load...
[oK
[ Cancel
eip
Depth
(ft)
Area
(ff2) fl
1 0 - 335.
335 -
- -.
-
1
--
2 4
10
3
4
5
6
7
8
9
ii
Outlet 1
Property Value
Name 1
Inlet Node STOR_1-1
Outlet Node POC-1
Description
Tag
In let Offset 0
Flap Gate NO
Rating Curve
Functional Cur
Coefficient 110.0
Bzponent 05
Tabular Curve
Curve NameJOUTi
User-assigned name of outlet
Rating Curve Editor
Curve Name
OUTI
Description
Load...
[Sa...] ve
OK
Cancel
-
-
Head
ft
Outflow
CFS _ E
1
2
0.00
0.042 _[ooi
0,083 J
4 0.125
- 01.167 0.001 -
6 0.208 0.001 -.
7 0.250 0.001
0.22 0.0011 --
0000
oocI - - 3
9 0,333 .j0.001
10 0.315 0.002
- 11 0.417 0.002
ATTACHMENT 8
Soil Map
469300 469402 469500 469900 469702 469802 469900 47ODDO 470102
Hydrologic Soil Group—San Diego County Area. California
33 54'N
44;I1 469300 469400 469500 469600 469702 469800 46990(1 470000 470100
MIN
\
c
4
e 8 N4 N
C
04
0
1/23/2014
Page 1 of 4
Map S: x8.5)sheet.
=Meters N 0 50 100 200 300
A Feet 0 200 400 800 1200
Map projection: Web Mercator Corner coordirrat. WGSB4 Edge tics: UTM Zone uN WGS84
Natural Resources Web Soil Survey
Conservation Service National Cooperative Soil Survey
Hydrologic Soil Group—San Diego County Area, California
MAP LEGEND MAP INFORMATION
DC
CID
0
Not rated or not available
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Background
alv. Aerial Photography
Area of interest (AOl)
Area of Interest A01)
Soils
Soil Rating Polygons
AID
B/D
CID
Li Not rated or not available
Soil Rating Lines
. A
AID
B
B/D
C
., CID
- D
Not rated or not available
Soil Rating Points
o A
o AID
• B
• BID
The soil surveys that comprise your AOl were mapped at 1 '24 000
Warning Soil Map may not be valid at this scale
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil line
placement. The maps do not show the small areas of contrasting
soils that could have been shown at a more detailed scale.
Please rely on the bar scale on each map sheet for map
measurements.
Source of Map Natural Resources Conservation Service
Web Soil Survey URL' http://websoilsurvey.nrcs.usda.gov
Coordinate System. Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator
projection. which preserves direction and shape but distorts
distance and area. A projection that preserves area, such as the
Albers equal-area conic projection, should be used if more accurate
calculations of distance or area are required.
This product is generated from the USDA-NRCS certified data as of
the version date(s) listed below.
Soil Survey Area San Diego County Area, California
Survey Area Data: Version 7. Nov 15, 2013
Soil map units are labeled (as space allows) for map scales 1:50,000
or larger.
Date(s) aerial images were photographed: May 3.2010—Jun 19.
2010
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps As a result, some minor shifting
of map unit boundaries may be evident.
i'Sl Natural Resources Web Soil Survey 1/23/2014
Conservation Service National Cooperative Soil Survey Page 2 of 4
Hydrologic Soil Group—San Diego County Area, California
Hydrologic Soil Group
Hydrologic Soil Group.—. Summary by Map Unit - San Diego County Area, California (CA638)
Map unit symbol Map unit name Rating } Acres in AOl Percent of AOl
CbC Carlsbad gravelly loamy B I 5.7 5.4% sand, 5 t 9 percent - I
-
slopes
CbD Carlsbad gravelly loamy B I 7.4 sand, 9 to 15 percent
slopes
GaF Gaviota fine sandy loam, 0 11.6 30 to 50 percent
slopes
LfC Las Flores-Urban land 0 18.6
complex, 2 to 9
percent slopes
F-W Lagoon water 30.4
3 Loamy alluvial land- D 4.3
Huerhuero complex, 9
to 50 percent slopes,
severely eroded
MIE Marina loamy coarse B 27.3 sand, 9 to 30 percent I
slopes
Totals for Area of Interest 105.2
7.0%
11.0%
17.6%
28.9%1
4.1%
_10!o
usDA Natural Resources Web Soil Survey 1/23/2014 Conservation Service National Cooperative Soil Survey Page 3 of 4
Hydrologic Soil Group—San Diego County Area, California
Description
Hydrologic soil groups are based on estimates of runoff potential. Soils are
assigned to one of four groups according to the rate of water infiltration when the
soils are not protected by vegetation, are thoroughly wet, and receive precipitation
from long-duration storms.
The soils in the United States are assigned to four groups (A, B, C, and D) and
three dual classes (ND, BID, and C/D). The groups are defined as follows:
Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly
wet. These consist mainly of deep, well drained to excessively drained sands or
gravelly sands. These soils have a high rate of water transmission.
Group B. Soils having a moderate infiltration rate when thoroughly wet. These
consist chiefly of moderately deep or deep, moderately well drained or well drained
soils that have moderately fine texture to moderately coarse texture. These soils
have a moderate rate of water transmission.
Group C. Soils having a slow infiltration rate when thoroughly wet. These consist
chiefly of soils having a layer that impedes the downward movement of water or
soils of moderately fine texture or fine texture. These soils have a slow rate of water
transmission.
Group D. Soils having a very slow infiltration rate (high runoff potential) when
thoroughly wet. These consist chiefly of clays that have a high shrink-swell
potential, soils that have a high water table, soils that have a claypan or clay layer
at or near the surface, and soils that are shallow over nearly impervious material.
These soils have a very slow rate of water transmission.
If a soil is assigned to a dual hydrologic group (AID, B/D, or C/D), the first letter is
for drained areas and the second is for undrained areas. Only the soils that in their
natural condition are in group D are assigned to dual classes.
Rating Options
Aggregation Method: Dominant Condition
Component Percent Cutoff. None Specified
Tie-break Rule: Higher
USDA Natural Resources Web Soil Survey 1/23/2014 Conservation Service National Cooperative Soil Survey Page 4 of 4
ATTACHMENT 9
Summary Files from the SWMM Model
Pre-Dev Output (POC-1)
EPA STORM WATER MANAGEMENT MODEL - VERSION 5.1 (Build 5.1.010) --------------------------------------------------------------
439-01 Martin Residence- Pre Development Condition Model
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
P.DII ...................NO
Snowmelt ...............NO
Groundwater ............NO
Flow Routing ...........NO
Water Quality ..........NO
Infiltration Method ......GREEN M4PT
Starting Date ............ AUG-28-1951 05:00:00
Ending Date ..............MAY-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 11.085 675.250
Evaporation Loss 0.020 1.202
Infiltration Loss 10.707 652.208
Surface Runoff 0.404 24.601
Final Storage 0.000 0.000
Continuity Error (%) -0.409
SWMM5.1 Page 1
Pre-Dev Output (POC-1)
* * * * * * * * * * * * * * * * * * * * * * * * * * Volume Volume
Flow Routing Continuity acre-feet 106 gal
**************************
Dry Weather Inflow 0.000 0.000
Wet Weather Inflow 0.404 0.132
Groundwater Inflow 0.000 0.000
RDII Inflow ..............0.000 0.000
External Inflow 0.000 0.000
External Outflow 0.404 0.132
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 (%) 0.000
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 106 gal CFS
DMA1 675.25 0.00
--------------------------------------------------------------------------------------------------------
1.20 652.21 24.60 0.13 0.20 0.036
Analysis begun on: Thu Nov 17 12:00:38 2016
Analysis ended on: Thu Nov 17 12:00:52 2016
Total elapsed time: 00:00:14
SWMM5.1 Page 2
Post-Dev Output (POC-1)
EPA STORM WATER MANAGEMENT MODEL - VERSION 5.1 (Build 5.1.010) --------------------------------------------------------------
439-01 Martin Residence- Post Development Condition Model
** * **** * **** * **** **** * ************* * *
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 ............AUG-28-1951 05:00:00
Ending Date ..............MAY-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
** **** ******** **** ** * * ** ** Volume Depth
Runoff Quantity Continuity acre-feet inches
**************************
Total Precipitation 10.455 675.250
Evaporation Loss 1.043 67.382
Infiltration Loss 1.528 98.698
Surface Runoff 8.102 523.261
Final Storage 0.001 0.032
SWMM5.1 Page 1
Post-Dev Output (POC-1)
Continuity Error (%) -2.092
* * * * * * * * * * * * * * * * * * * * * * * * * * Volume Volume
Flow Routing Continuity acre-feet 10"6 gal
** **** * *** ** *** ********** *
Dry Weather Inflow 0.000 0.000
Wet Weather Inflow 8.102 2.640
Groundwater Inflow 0.000 0.000
RDII Inflow ............. 0.000 0.000
External Inflow 0.000 0.000
External Outflow 8.101 2.640
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 (%) 0.010
********************************
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
Subcatchment Runoff Summary
** * * ******** * ** * * *******
--------------------------------------------------------------------------------------------------------
Total Total Total Total Total Total Peak Runoff
- SWMM5.1 Page 2
Post-Dev Output (POC-1)
Precip Runon Evap Infil Runoff Runoff Runoff Coeff
Subcatchment in in in in in 10'6 gal CFS
DMA 1-1 675.25 0.00
--------------------------------------------------------------------------------------------------------
65.41 99.02 524.96 2.64 0.22 0.777
BY-PASS-1-1 675.25 0.00 674.69 0.00 0.00 0.00 0.00 0.000
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
STOR1-1 STORAGE 0.07 3.82 3.82 18857 11:50 3.82
** ** * * * * * * * * ***** **
Node Inflow Summary
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 106 gal 10"6 gal Percent
POC-1 OUTFALL 0.00
-------------------------------------------------------------------------------------------------
0.22 18857 11:50 0 2.64 0.000
STOR1-1 STORAGE 0.22 0.22 18857 12:01 2.64 2.64 0.010
**********************
Node Surcharge Summary
**********************
Surcharging occurs when water rises above the top of the highest conduit. ---------------------------------------------------------------------
Max. Height Mm. Depth
Hours Above Crown Below Rim
Node Type Surcharged Feet Feet
SWMM5.1 Page 3
Post-Dev Output (POC-1)
---------------------------------------------------------------------
STOR1-1 STORAGE 497370.00 3.816 0.184
* ** *** * ******* **** * **
Node Flooding Summary
*********************
No nodes were flooded.
Storage Volume Summary
--------------------------------------------------------------------------------------------------
Average Avg Evap Exf ii 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
STOR1-1 0.023 2 0 0 1.279 95 18857 11:49 0.22
***********************
Outfall Loading Summary
* ********** *** * * ****
-----------------------------------------------------------
Flow Avg Max Total
Freq Flow Flow Volume
Outfall Node Pcnt CFS CFS 10''6 gal -----------------------------------------------------------
FOC-1 9.44 0.00 0.22 2.640 -----------------------------------------------------------
System 9.44 0.00 0.22 2.640
Link Flow Summary
-----------------------------------------------------------------------------
Maximum Time of Max Maximum Max! Max!
SWMM5.1 Page 4
Post-Dev Output (POC-1)
IFlowl Occurrence lVelocl Full Full
Link Type CFS days hr:min ft/sec Flow Depth -----------------------------------------------------------------------------
1 DUMMY 0.22 18857 11:50
Conduit Surcharge Summary
No conduits were surcharged.
Analysis begun on: Thu Nov 17 14:17:55 2016
Analysis ended on: Thu Nov 17 14:18:21 2016
Total elapsed time: 00:00:26
SWMM 5.1 Page 5