HomeMy WebLinkAboutCT 02-17; FAIR OAKS VALLEY; SWMM MODELING; 2012-09-12TECHNICAL MEMORANDUM:
SWMM Modeling for
Hydromodification Compliance of:
Fair Oaks Valley
Prepared for:
Mr. Chuck Duvivier
September 12, 2012
Tory RJWalker, R.C.E. 45005
President
TORY R. WALKER ENGINEERING, INC.
WATER RESOURCES PLANNING & ENGINEERING
122 CIVIC CENTER DRIVE, SUITE 206, VISTA, CA 92084 PH:76a4l4-9212 WWW.TRWENGINEERING.COM
TORY R. WALKER ENGINEERING, INC.
WATER RESOURCES PLANNING & ENGINEERING
TECHNICAL MEMORANDUM
TO: Mr. Chuck Duvivier
FROM: Tory Walker, PE, CFM, LEED GA
Luis Parra, PhD, PE, CPSWa ToR, D.WRE.
DATE: September 12, 2012
RE: Summary of SWMM Modeling for Hydromodification Compliance for the Fair Oaks
Valley Project, Carlsbad, CA.
INTRODUCTION
This memorandum summarizes the approach used to model the proposed Fair Oaks Valley Project in
Carlsbad using the Environmental Protection Agency (EPA) Storm Water Management Model 5.0
(SWMM). SWMM models were prepared for the pre and post-developed conditions at the site in order
to determine if the proposed LID and detention facility has the sufficient volume to meet the current
Hydromodification Management Plan (HMP) requirements from the San Diego Regional Water Quality
Control Board (SDRWQCB).
SWMM MODEL DEVELOPMENT
Two (2) SWMM models were prepared for this study, one for the pre and another for the post
developed conditions, both discharging to a single Point of Compliance (POC-l) - the existing natural
channel located in the southern portion of the project site. 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). For both SWMM models, flow duration curves were prepared to determine if the proposed
HMP facility was sufficient to meet the current HMP requirements.
The inputs required to develop SWMM models include rainfall, watershed characteristics, and BMP
configurations. 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 among the three gages used for modeling
the characteristics of the County by the approved calculator (Lindbergh, Wohlford and Oceanside).
Evaporation for the site was modeled using average monthly values from the County hourly dataset.
The site was modeled with hydrologic soil Type D as determined from the County of San Diego
Hydrology Manual Soils Maps and site specific geotechnical investigation study from the USDA Web Soil
Survey. Soils have been assumed to be uncompacted in the natural existing condition while fully
compacted in the post developed conditions. Other SWMM inputs for the subareas are discussed in the
appendices to this document, where the selection of the parameters is explained in detail.
Regarding additional points of compliance, POC-2 does not change between pre and post-developed
conditions, so no modeling is required. POC-3 reduces in area and also remains the same land use
(natural). Therefore, no modeling is required.
1 22 Civic Center Drive, Suite 206, Vista, CA 92084 I Ph: 760.41 4,921 2 Fx: 760,41 4.9277 | www,Trwengineering,Com
Fair Oaks Valley SWMM Memo
September 12,2012
HMP MODELING
Storm water runoff from the developed project site is routed to a single POC - the existing natural
channel located in the southern portion of the project site (POC-l). Runoff from the project site is
conveyed via a single HMP bio-retention basin prior to discharging from the site.
It is assumed all storm water quality requirements for the project will be met by onsite BMPs and will
not be discussed within this document. For further information in regards to storm water quality
requirements for the project, please refer to the site specific Storm Water Management Plan (SWMP). it
should be noted however that 100% of the SS"* percentile volume has been accounted for within the
basin design such that all treatment volumes are contained within the bio-retention facility beneath the
initial above ground basin orifice.
In other words, the volume of voids of the facility beneath the invert of the lower surface orifices is
larger than the volume of runoff generated by the 85'^ percentile 24 hour storm event.
TABLE 1 - SUMMARY OF DEVELOPED CONDITIONS
DMA Tributary Area
(Ac)
impervious
Percentage'*' Slope
85"^ Percentile
Treatment
Volume (ft^)
1 25.31 49.1% 5.5% 33,855
(1): The impervious percentage includes the area of streets and sidewalks plus the impervious area of each lot,
conservatively assumed equal to 5,000 sq.ft. per lot.
TABLE 2 - SUMMARY OF POC TRIBUTARY AREAS
Point of Compliance Pre-Developed Conditions
(Ac)
Post-Developed Conditions
(Ac)
POC-l (Modeled) 24.07 (71.64-47.58) 25.31 (21.51+1.76+1.14+0.9)
POC-l (Not Modeled)'^' 47.58 47.58 (47.21+0.37)
POC-2 (Not Modeled)'^' 0.87 0.87
POC-3 (Not Modeled)'^' 8.80 7.56
TOTAL 81.32 81.32
(1) : Area and land use does not change {undisturbed natural areas). Therefore no modeling required.
(2) : 1.24 acres previously draining to POC-3 in pre-developed conditions have been diverted to POC-l due to
grading. Land use does not change, thus no modeling is required.
Flow from the proposed project site (inclusive of the proposed extension of Melrose Drive) will drain to
a single bio-retention basin located in the southern portion of the proposed site. In developed
conditions, the basin bottom elevation will be 382 feet, while the top elevation is 388 feet.
Flow will exit the basin via multiple orifices constructed into the side of the proposed riser structure. An
initial series of eight (8) 1.5-inch orifices will be located at an invert of 384 feet, with a secondary series
of eight (8) 6-inch orifices located at 386 feet. The riser structure will be built to a top elevation of 387
feet.
259-01
Fair Oaks Valley SWMM Memo
September 12,2012
Beneath the basin invert lies the proposed LID bio-retention portion of the drainage facility. This portion
of the basin comprises of a 24-inch layer of amended soil (a highly sandy, organic rich composite with a
drain time of at least 5 inches/hr) and a 24-inch layer of gravel for additional detention. A French drain
system is to be located beneath the bioretention layers to intercept treated storm water and convey
these flows to a single 3-inch outlet orifice. Detained flows will then discharge via a storm drain,
draining to the existing natural channel prior to leaving the project site.
It should be noted that detailed outlet structure location and elevations will be detailed on the
construction plans based on the recommendations of this study.
BMP MODELING FOR HMP PURPOSES
Modeling of dual purpose Water Quality/HMP BMPs
A single bio-retention basin is proposed for water quality treatment and hydromodifcation conformance
within the project site.
Table 3 illustrates the dimensions required for HMP compliance according to the SWMM model that was
undertaken for the project.
TABLE 3 - SUMMARY OF DUAL PURPOSE BMPS: Biorention witli Surface Ponding
DMA
Impervious
Tributary
Area (ft')
DIMENSIONS
DMA
Impervious
Tributary
Area (ft') Area
Gravel
Depth'",
(in)
Lower
Ortf.
D
(in)"'
Surf ace Orifice
(D, invert)'*'(in)
Total Surface
Depth'" (in)
Mser's
ipwifert"'
(in)
Riser's
length'^)
(ft)
1 541,317 10,410 24 3 8xl.5"@24"
8x6"@48" 72" 60" 12.57
Notes: (1): Area of amended soil equal to gravel depth
(2) : Gravel depth needed to comply with hydromodification purposes
(3) : Diameter of orifice in gravel layer w/ith invert at bottom of layer; tied with hydromod min threshold (0,102).
(4) : Diameter of surface orifice (N/A implies no orifice), and invert of orifice (measured from surface above).
(5) : Total depth of ponding at the surface (including free-board).
(6) : Invert elevation of riser (measured from above).
(7) : 12.57 ft equals to a 4 ft dia. riser pipe
FLOW DURATION CURVE COMPARISON
The Flow Duration Curve (FDC) for the site was compared at the single POC by exporting the hourly
runoff time series results from SWMM to a spreadsheet. FDC was compared between 10% of the
existing condition Q2 up to the existing condition QIQ. The Q2 and Qio were determined using 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
259-01
Fair Oaks Valley SWMM Memo
September 12, 2012
was also used within the spreadsheet to ensure that the results were similar to those obtained by the
SWMM Model.
The range between 10% of Cb and Qio 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 "\" 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 comparisons at the POC are illustrated in Figure 1 in both normal and logarithmic scale.
Attachment 7 provides a detailed drainage exhibit for the post-developed condition.
As can be seen in Figure 1, the FDC for the proposed condition with the HMP BMP is within 110% of the
curve for the existing condition in both peak flows and durations. The additional runoff volume
generated from developing the site will be released to the adjacent natural channel at a flow rate below
the 10% Q2 lower threshold. Additionally, the project will also not increase peak flow rates between the
Q2 and the Qio, as shown in the graphic and also in the peak flow table in Attachment 1.
SUMMARY
This study has demonstrated that the proposed HMP BMP provided within the Fair Oaks Valley
development are sufficient to meet the current HMP criteria if the cross-section areas and volumes
recommended within this technical memorandum are incorporated within the proposed project site.
KEY ASSUMPTIONS
1. Type D Soils are representative of the existing condition site.
ATTACHMENTS
1. CI2 to Qio 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. Elevation vs. Area Curves and Elevations vs. Discharge Curves to be used in SWMM
5. Pre & Post Development Maps, Project plan and section sketches
6. SWMM Input Data in Input Format (Existing and Proposed Models)
7. SWMM Screens and Explanation of Significant Variables
8. Justification of Soil Type D Conditions
9. Summary files from the SWMM Model
259-01
Fair Oaks Valley SWMM Memo
September 12, 2012
Fair Oaks Valley - Flow Duration Curve
1400
13 00
ITDO"
1100
1000
6,00
500
400
300
2 00
= = = = =: : : = - = = = =. = .= = = :•= = =;= =:: : = : =• ^ = = = = = : : = = = = = = 89 _J ,
-1 " &
w
Of
w — M4
w - -— ^ . _ .
• —
1
Qi V. .... _ _ _
,
Existing
Proposed
Qx
Existing
Proposed
Qx
).5<t, -. ,|
__
0.3Qj _ _ — _ ..LL - -0
— —^ r-in_ D.IO2 —r
-\
0001
Peicentage of time exceeded (%)
Fair Oaks Valley - Flow Duration Curve
17 00
1600
15 00
14 00
13 00
12 00
1100
1000
2 s
C 800
700
600
500
400
300
2 00
100
000
---7---1?
-h h
'"i
a. a.
Existing
Proposed
Clx
Existing
Proposed
Clx
n If ---- ft ro 0.1'
0.15
Percentage of time exceeded (H)
Figure la and lb. Flow Duration Curve Comparison (logarithmic and normal "x" scale)
259-01
Fair Oaks Valley SWMM Memo
September 12, 2012
ATTACHMENT 1.
Q2 to Qio Comparison Table - POC
Return Period Existing Condition (cfs) Mitigated Condition (cfs) Reduction, Exist -
IVIitigated (cfs)
2-year 10.818 6.443 4.375
3-Year 12.718 7.530 5.189
4-year 13.914 7.825 6.089
5-year 14.801 8.044 6.756
6-year 15.125 8.372 6.754
7-year 16.444 11.035 5.409
8-year 16.704 11.807 4.897
9-year 16.846 12.651 4.195
lO-year 17.170 14.779 2.391
259-01
ATTACHMENT 2
FLOW DURATION CURVE ANALYSIS
1) Fiow duration curve shall not exceed the existing conditions by more than 10%, neither in
peak flow nor duration.
The figure on the following page illustrates 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 O.IOCI2 - 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 Carlsbad 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 Cb to Qio) but
also all intermediate flows are shown (30% of Q2, 50% of Q2, Q2, Q3, Q4, Qs, Qe, Q?, Qs and Qg) in
order to demonstrate compliance at any range Qx - Qx+i- 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 Qj from i = 2 to 10). TRWE 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 Qi values are also added into the flow-duration plot.
Fair Oaks Valley - Flow Duration Curve
17.00
16.00
15.00
14.00
13.00
12.00
11.00
10.00
— 9.00
O 8.00
7.00
6.00
5.00
4.00
3.00
2.00
0.00
ii ;j =: 3 : : = : =5 : =:: :: = =|:t : = : = : = : = : = : : = : = ^ = : ^ : 1= : =|: 4: :| = : = : = : = ii
Of
U4
Existing
^—^ Proposed
Qx
Existing
^—^ Proposed
Qx
•-
.i^Si2
. —• CIQ2 01^2 CIQ2
0.001 0.01 0.1
Percentage of time exceeded (%)
Fair Oaks Valley - Flow Duration Curve
17.00
16.00
15.00
14.00
13.00
12.00
11.00
10.00
8.00
7.00
6.00
5.00
4.00
3.00
2.00
1.00
0.00
•<7
rv-
——1
ar
.
^2
1
• Existing
• Proposed
•Qx
• Existing
• Proposed
•Qx
—%—'"v—
0.5tl2 V ^ 5Q2
—%—'"v—
0.5tl2 V ^ 5Q2
w 1
1 1
0.05 0.1 0.15 0.2
Percentage of time exceeded (%)
0.25 0.3
Flow Duration Curve Data for Fair Oaks Valley, Carlsbad CA
02 =
010 =
Step =
Count:
10.82 cfs
17.17 cfs
0.1625 cfs
499680 hours
57.00 years
Fraction 10 %
Interval
Existing Condition Underground Detention 0 atimized Pass or
Fail? Interval Q(cfs) Hours > Q %tlme Hours>Q Ktime Post/Pre
Pass or
Fail?
1 1.082 927 1.86E-01 488 9.77E-02 53% Pass
2 1.244 850 1.70E-01 439 8.79E-02 52% Pass
3 1.407 780 1.56E-01 400 8.01E-02 51% Pass
4 1.569 716 1.43E-01 367 7.34E-02 51% Pass
5 1.732 658 1.32E-01 340 6.80E-02 52% Pass
6 1.894 609 1.22E-01 314 6.28E-02 52% Pass
7 2.057 557 l.llE-01 294 5.88E-02 53% Pass
8 2.219 520 1.04E-01 267 5.34E-02 51% Pass
9 2.382 480 9.61E-02 247 4.94E-02 51% Pass
10 2.544 448 8.97E-02 235 4.70E-02 52% Pass
11 2.707 422 8.45 E-02 218 4.36E-02 52% Pass
12 2.869 391 7.83E-02 204 4.08E-02 52% Pass
13 3.032 358 7.16E-02 193 3.86E-02 54% Pass
14 3.194 330 6.60E-02 179 3.58E-02 54% Pass
15 3.357 310 6.20E-02 165 3.30E-02 53% Pass
16 3.519 288 5.76E-02 159 3.18E-02 55% Pass
17 3.682 280 5.60E-02 151 3.02E-02 54% Pass
18 3.845 266 5.32E-02 144 2.88E-02 54% Pass
19 4.007 244 4.88E-02 139 2.78E-02 57% Pass
20 4.170 226 4.52E-02 130 2.60E-02 58% Pass
21 4.332 212 4.24E-02 125 2.50E-02 59% Pass
22 4.495 203 4.06E-02 116 2.32E-02 57% Pass
23 4.657 191 3.82E-02 113 2.26E-02 59% Pass
24 4.820 182 3.64E-02 106 2.12E-02 58% Pass
25 4.982 174 3.48E-02 101 2.02E-02 58% Pass
26 5.145 164 3.28E-02 94 1.88E-02 57% Pass
27 5.307 151 3.02E-02 90 1.80E-02 60% Pass
28 5.470 142 2.84E-02 85 1.70E-02 60% Pass
29 5.632 131 2.62E-02 81 1.62E-02 62% Pass
30 5.795 118 2.36E-02 77 1.54E-02 65% Pass
31 5.957 114 2.28E-02 74 1.48E-02 65% Pass
32 6.120 110 2.20E-02 70 1.40E-02 64% Pass
33 6.282 102 2.04E-02 60 1.20E-02 59% Pass
34 6.445 97 1.94E-02 53 1.06E-02 55% Pass
35 6.607 93 1.86E-02 49 9.81E-03 53% Pass
36 6.770 89 1.78E-02 46 9.21E-03 52% Pass
Existing Condition Underground Detention Optimized Pass or
Fail? Interval Q(efs) Hours > Q %time Hours>Q %tlme Post/Pre
Pass or
Fail?
37 6.932 87 1.74E-02 38 7.60E-03 44% Pass
38 7.095 86 1.72E-02 35 7.00E-03 41% Pass
39 7.257 81 1.62E-02 34 6.80E-03 42% Pass
40 7.420 77 1.54E-02 33 6.60E-03 43% Pass
41 7.582 72 1.44E-02 28 5.60E-03 39% Pass
42 7.745 69 1.38E-02 21 4.20E-03 30% Pass
43 7.907 63 1.26E-02 20 4.00E-03 32% Pass
44 8.070 61 1.22E-02 16 3.20E-03 26% Pass
45 8.232 58 1.16E-02 13 2.60E-03 22% Pass
46 8.395 55 l.lOE-02 12 2.40E-03 22% Pass
47 8.557 55 l.lOE-02 11 2.20E-03 20% Pass
48 8.720 51 1.02E-02 11 2.20E-03 22% Pass
49 8.882 48 9.61E-03 11 2.20E-03 23% Pass
50 9.045 48 9.61E-03 11 2.20E-03 23% Pass
51 9.207 44 8.81E-03 11 2.20E-03 25% Pass
52 9.370 43 8.61E-03 11 2.20E-03 26% Pass
53 9.532 40 8.01E-03 11 2.20E-03 28% Pass
54 9.695 39 7.80E-03 11 2.20E-03 28% Pass
55 9.857 39 7.80E-03 11 2.20E-03 28% Pass
56 10.020 38 7.60E-03 11 2.20E-03 29% Pass
57 10.182 36 7.20E-03 11 2.20E-03 31% Pass
58 10.345 35 7.00E-03 11 2.20E-03 31% Pass
59 10.507 34 6.80E-03 11 2.20E-03 32% Pass
60 10.670 33 6.60E-03 10 2.00E-03 30% Pass
61 10.833 32 6.40E-03 10 2.00E-03 31% Pass
62 10.995 32 6.40E-03 10 2.00E-03 31% Pass
63 11.158 32 6.40E-03 10 2.00E-03 31% Pass
64 11.320 31 6.20E-03 10 2.00E-03 32% Pass
65 11.483 28 5.60E-03 10 2.00E-03 36% Pass
66 11.645 28 5.60E-03 9 1.80E-03 32% Pass
67 11.808 28 5.60E-03 8 1.60E-03 29% Pass
68 11.970 26 5.20E-03 7 1.40E-03 27% Pass
69 12.133 26 5.20E-03 7 1.40E-03 27% Pass
70 12.295 26 5.20E-03 7 1.40E-03 27% Pass
71 12.458 22 4.40E-03 7 1.40E-03 32% Pass
72 12.620 21 4.20E-03 7 1.40E-03 33% Pass
73 12.783 21 4.20E-03 7 1.40E-03 33% Pass
74 12.945 21 4.20E-03 7 1.40E-03 33% Pass
75 13.108 20 4.00E-03 7 1.40E-03 35% Pass
76 13.270 20 4.00E-03 7 1.40E-03 35% Pass
77 13.433 19 3.80E-03 7 1.40E-03 37% Pass
78 13.595 17 3.40E-03 7 1.40E-03 41% Pass
79 13.758 16 3.20E-03 7 1.40E-03 44% Pass
80 13.920 16 3.20E-03 7 1.40E-03 44% Pass
81 14.083 16 3.20E-03 7 1.40E-03 44% Pass
Interval
Existing Cond tton Underground Detention 0| itimized Pass or
Fail? Interval Q(cfs) Hours > Q % time Hours>Q %tlme Post/Pre
Pass or
Fail?
82 14.245 16 3.20E-03 7 1.40E-03 44% Pass
83 14.408 16 3.20E-03 7 1.40E-03 44% Pass
84 14.570 15 3.00E-03 7 1.40E-03 47% Pass
85 14.733 14 2.80E-03 7 1.40E-03 50% Pass
86 14.895 13 2.60E-03 7 1.40E-03 54% Pass
87 15.058 11 2.20E-03 7 1.40E-03 64% Pass
88 15.220 11 2.20E-03 7 1.40E-03 64% Pass
89 15.383 11 2.20E-03 6 1.20E-03 55% Pass
90 15.545 11 2.20E-03 6 1.20E-03 55% Pass
91 15.708 10 2.00E-03 6 1.20E-03 60% Pass
92 15.870 10 2.00E-03 6 1.20E-03 60% Pass
93 16.033 9 1.80E-03 6 1.20E-03 67% Pass
94 16.195 9 1.80E-03 6 1.20E-03 67% Pass
95 16.358 8 1.60E-03 5 l.OOE-03 63% Pass
96 16.520 8 1.60E-03 5 l.OOE-03 63% Pass
97 16.683 7 1.40E-03 5 l.OOE-03 71% Pass
98 16.845 6 1.20E-03 5 l.OOE-03 83% Pass
99 17.008 6 1.20E-03 5 l.OOE-03 83% Pass
100 17.170 6 1.20E-03 4 8.01E-04 67% Pass
Peak Flows calculated with Cunnane Plotting Position
Return Period
Pre-dev. Q Post-Deiv. Q Reduction
10 17.170 14.779 2.391
9 16.846 12.651 4.195
8 16.704 11.807 4.897
7 16.444 11.035 5.409
6 15.125 8.372 6.754
5 14.801 8.044 6.756
4 13.914 7.825 6.089
3 12.718 7.530 5.189
2 10.818 6.443 4.375
ATTACHiVIENT3
List of the ''n'' Largest Peaks: Pre & Post-Developed Conditions
Ust of Peak events and Determination of P2 and PIO (Post-Development)
T Cunnane Weibull Period of Return
10 14.78 15.41 Peaks Date Posit Weibull Cunnane
9 12.65 13.65 4.381 12/18/1967 57 1.02 1.01
8 11.81 11.88 4.403 11/29/1985 56 1.04 1.03
7 11.04 11.36 4.566 1/18/1952 55 1.05 1.05
6 8.37 8.96 4.592 2/2/1960 54 1.07 1.07
5 8.04 8.08 4.74 4/1/1958 53 1.09 1.09
4 7.82 7.87 4.832 3/1/1983 52 1.12 1.11
3 7.53 7.54 4.946 10/29/2000 51 1.14 1.13
2 6.44 6.44 5.021 3/2/1980 50 1.16 1.15
5.071 1/22/1967 49 1.18 1.18
5.281 1/13/1957 48 1.21 1.20
Note: 5.295 1/16/1972 47 1.23 1.23
Cunnane is the preferred 5.369 11/30/2007 46 1.26 1.25
method by the HMP permit. 5.377 12/24/1971 45 1.29 1.28
5.461 1/25/1969 44 1.32 1.31
5.58 1/13/1997 43 1.35 1.34
5.682 2/26/2004 42 1.38 1.38
5.746 2/17/1998 41 1.41 1.41
5.848 8/17/1977 40 1.45 1.44
6.022 1/14/1993 39 1.49 1.48
6.036 3/5/1995 38 1.53 1.52
6.161 3/11/1995 37 1.57 1.56
6.18 9/24/1986 36 1.61 1.61
6.214 2/18/1980 35 1.66 1.65
6.27 1/15/1978 34 1.71 1.70
6.315 12/30/1991 33 1.76 1.75
6.37 1/9/2005 32 1.81 1.81
6.39 1/16/1993 31 1.87 1.87
6.434 12/5/1966 30 1.93 1.93
6.443 2/3/1998 29 2.00 2.00
6.455 11/22/1996 28 2.07 2.07
6.544 1/11/1980 27 2.15 2.15
6.572 12/25/1983 26 2.23 2.23
6.832 2/20/1980 25 2.32 2.33
6.854 2/23/2005 24 2.42 2.42
7.032 2/18/2005 23 2.52 2.53
7.409 2/23/1998 22 2.64 2.65
7.42 1/16/1978 21 2.76 2.78
7.472 2/15/1986 20 2.90 2.92
7.583 2/10/1978 19 3.05 3.08
7.621 1/20/1962 18 3.22 3.25
7.627 10/27/2004 17 3.41 3.45
7.729 1/16/1952 16 3.63 3.67
7.767 3/8/1968 15 3.87 3.92
7.97 1/6/1979 14 4.14 4.21
8.015 11/22/1965 13 4.46 4.54
8.019 3/17/1982 12 4.83 4.93
8.19 2/4/1958 11 5.27 5.40
8.23 2/25/2003 10 5.80 5.96
10.587 2/22/2008 9 6.44 6.65
11.711 1/29/1980 8 7.25 7.53
11.942 3/1/1978 7 8.29 8.67
15.235 10/1/1983 6 9.67 10.21
16.221 2/25/1969 5 11.60 12.43
17.258 1/4/1978 4 14.50 15.89
23.008 1/15/1979 3 19.33 22.00
23.388 1/4/1995 2 29.00 35.75
27.273 4/14/2003 1 58.00 95.33
List of Peak events and Determination of P2 and PIO (Pre-Development)
T Cunnane Weibull Period of Return
10 17.17 18.00 Peaks Date Posit Weibull Cunnane
9 16.85 17.00 7.802 2/18/1980 57 1.02 1.01
8 16.70 16.72 7.812 1/6/1979 56 1.04 1.03
7 16.44 16.56 7.852 12/24/1988 55 1.05 1.05
6 15.13 15.44 7.948 2/23/2005 54 1.07 1.07
5 14.80 14.86 8.127 2/12/2003 53 1.09 1.09
4 13.91 14.05 8.132 3/1/1983 52 1.12 1.11
3 12.72 12.79 8.211 3/11/1995 51 1.14 1.13
2 10.82 10.82 8.318 3/17/1963 50 1.16 1.15
8.327 3/15/1986 49 1.18 1.18
8.348 1/11/2005 48 1.21 1.20
Note: 8.594 8/17/1977 47 1.23 1.23
Cunnane Is the preferred 8.639 2/22/1998 46 1.26 1.25
method by the HMP permit. 8.699 1/18/1993 45 1.29 1.28
8.75 2/18/1993 44 1.32 1.31
8.848 2/4/1994 43 1.35 1.34
8.865 4/27/1960 42 1.38 1.38
9.106 1/16/1972 41 1.41 1.41
9.121 1/6/2008 40 1.45 1.44
9.131 11/11/1985 39 1.49 1.48
9.314 2/15/1986 38 1.53 1.52
9.428 2/22/2008 37 1.57 1.56
9.429 11/15/1952 36 1.61 1.61
9.529 10/20/2004 35 1.66 1.65
9.636 2/14/1998 34 1.71 1.70
10.111 2/16/1980 33 1.76 1.75
10.28 12/2/1961 32 1.81 1.81
10.422 1/27/2008 31 1.87 1.87
10.543 1/29/1980 30 1.93 1.93
10.818 1/16/1978 29 2.00 2.00
11.171 2/17/1998 28 2.07 2.07
11.339 12/19/1970 27 2.15 2.15
11.399 2/27/1983 26 2.23 2.23
11.409 1/29/1983 25 2.32 2.33
11.915 3/2/1980 24 2.42 2.42
11.941 2/23/1998 23 2.52 2.53
12.419 2/3/1998 22 2.64 2.65
12.433 12/30/1991 21 2.76 2.78
12.442 11/22/1965 20 2.90 2.92
12.973 2/10/1978 19 3.05 3.08
13.299 4/1/1958 18 3.22 3.25
13.564 10/29/2000 17 3.41 3.45
13.565 3/17/1982 16 3.63 3.67
13.711 1/14/1993 15 3.87 3.92
14.421 3/1/1978 14 4.14 4.21
14.623 1/16/1952 13 4.46 4.54
14.762 2/18/2005 12 4.83 4.93
15.023 2/20/1980 11 5.27 5.40
15.051 10/27/2004 10 5.80 5.96
16.289 9/23/1986 9 6.44 6.65
16.679 2/25/1969 8 7.25 7.53
16.738 2/4/1958 7 8.29 8.67
17.24 2/25/2003 6 9.67 10.21
21.673 1/4/1995 5 11.60 12.43
22.329 1/15/1979 4 14.50 15.89
22.979 1/4/1978 3 19.33 22.00
23.341 10/1/1983 2 29.00 35.75
26.1 4/14/2003 1 58.00 95.33
ATTACHMENT 4
AREA VS ELEVATION
The area vs. elevation curve in the model is calculated in Excel and imported into the model. A
table of the stage-area input used for this SWMM model is provided on the following page.
DISCHARGE VS ELEVATION
The total discharge peak flow is imported from an Excel spreadsheet that calculates the
discharge vs. elevation of the multiple outlet systems.
The orifices have been selected to maximize their size while still restricting flows to conform
with the required 10% of the Q2 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 conformance with
HMP requirements.
In order to further reduce the risk of blockage of the orifices, a debris screen will be fitted to
the base invert of the orifices located within the detention basins. Regular maintenance of the
riser and orifices must be performed to ensure potential blockages are minimized. A detail of
the orifice and riser structure is provided in Attachment 5 of this memorandum.
The stage-storage and stage-discharge calculations have been provided on the following pages.
Outlet structure for Discharge of Bio-Retention Basin Al
Discharge vs Elevation Table
Low orifice: 1.5 " Lower weir:
Number: 8 Invert: 3.00 ft
Cg-low: 0.61 B 12.57 ft
Middle orifice: 6 "
number of orif: 8 Emergency weir:
Cg-middle: 0.61 Invert: 0.00 ft
Invert elev: 2.00 ft B: 0 ft
h H/D-low H/D-mid Qlow-orif Qlow-weir Qtot-low QmldK>rif Qmid-weir Qtot-med Qweir Qemerg Qtot
(ft) --(cfs) (cfs) (cfs) (cfs) (cfs) (cfs) (cfs) (cfs) (cfs)
0 0 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
0.05 0.4 0.000 0.000 0.022 0.022 0.000 0.000 0.000 0.000 0.000 0.022
0.1 0.8 0.000 0.093 0.079 0.079 0.000 0.000 0.000 0.000 0.000 0.079
0.15 1.2 0.000 0.142 0.152 0.142 0.000 0.000 0.000 0.000 0.000 0.142
0.2 1.6 0.000 0.178 0.223 0.178 0.000 0.000 0.000 0.000 0.000 0.178
0.25 2 0.000 0.208 0.276 0.208 0.000 0.000 0.000 0.000 0.000 0.208
0.3 2.4 0.000 0.234 0.304 0.234 0.000 0.000 0.000 0.000 0.000 0.234
0.35 2.8 0.000 0.258 0.311 0.258 0.000 0.000 0.000 0.000 0.000 0.258
0.4 3.2 0.000 0.279 0.317 0.279 0.000 0.000 0.000 0.000 0.000 0.279
0.45 3.6 0.000 0.299 0.365 0.299 0.000 0.000 0.000 0.000 0.000 0.299
0.5 4 0.000 0.318 0.522 0.318 0.000 0.000 0.000 0.000 0.000 0.318
0.55 4.4 0.000 0.336 0.883 0.336 0.000 0.000 0.000 0.000 0.000 0.336
0.6 4.8 0.000 0.352 1.579 0.352 0.000 0.000 0.000 0.000 0.000 0.352
0.65 5.2 0.000 0.368 2.779 0.368 0.000 0.000 0.000 0.000 0.000 0.368
0.7 5.6 0.000 0.384 4.692 0.384 0.000 0.000 0.000 0.000 0.000 0.384
0.75 6 0.000 0.398 7.578 0.398 0.000 0.000 0.000 0.000 0.000 0.398
0.8 6.4 0.000 0.413 11.745 0.413 0.000 0.000 0.000 0.000 0.000 0.413
0.85 6.8 0.000 0.426 17.558 0.426 0.000 0.000 0.000 0.000 0.000 0.426
0.9 7.2 0.000 0.440 25.442 0.440 0.000 0.000 0.000 0.000 0.000 0.440
0.95 7.6 0.000 0.453 35.885 0.453 0.000 0.000 0.000 0.000 0.000 0.453
1 8 0.000 0.465 49.445 0.465 0.000 0.000 0.000 0.000 0.000 0.465
1.05 8.4 0.000 0.478 66.752 0.478 0.000 0.000 0.000 0.000 0.000 0.478
1.1 8.8 0.000 0.490 88.515 0.490 0.000 0.000 0.000 0.000 0.000 0.490
1.15 9.2 0.000 0.501 115.523 0.501 0.000 0.000 0.000 0.000 0.000 0.501
1.2 9.6 0.000 0.513 148.651 0.513 0.000 0.000 0.000 0.000 0.000 0.513
1.25 10 0.000 0.524 188.866 0.524 0.000 0.000 0.000 0.000 0.000 0.524
1.3 10.4 0.000 0.535 237.228 0.535 0.000 0.000 0.000 0.000 0.000 0.535
1.35 10.8 0.000 0.545 294.896 0.545 0.000 0.000 0.000 0.000 0.000 0.545
1.4 11.2 0.000 0.556 363.135 0.556 0.000 0.000 0.000 0.000 0.000 0.556
1.45 11.6 0.000 0.566 443.314 0.566 0.000 0.000 0.000 0.000 0.000 0.566
1.5 12 0.000 0.576 536.918 0.576 0.000 0.000 0.000 0.000 0.000 0.576
1.55 12.4 0.000 0.586 645.545 0.586 0.000 0.000 0.000 0.000 0.000 0.586
1.6 12.8 0.000 0.596 770.915 0.596 0.000 0.000 0.000 0.000 0.000 0.596
1.65 13.2 0.000 0.606 914.875 0.606 0.000 0.000 0.000 0.000 0.000 0.606
1.7 13.6 0.000 0.615 1079.400 0.615 0.000 0.000 0.000 0.000 0.000 0.615
1.75 14 0.000 0.624 1266.597 0.624 0.000 0.000 0.000 0.000 0.000 0.624
1.8 14.4 0.000 0.633 1478.715 0.633 0.000 0.000 0.000 0.000 0.000 0.633
1.85 14.8 0.000 0.643 1718.143 0.643 0.000 0.000 0.000 0.000 0.000 0.643
1.9 15.2 0.000 0.651 1987.417 0.651 0.000 0.000 0.000 0.000 0.000 0.651
1.95 15.6 0.000 0.660 2289.225 0.660 0.000 0.000 0.000 0.000 0.000 0.660
2 16 0.000 0.669 2626.411 0.669 0.000 0.000 0.000 0.000 0.000 0.669
2.05 16.4 0.100 0.678 3001.978 0.678 0.000 0.049 0.049 0.000 0.000 0.726
2.1 16.8 0.200 0.686 3419.093 0.686 0.000 0.188 0.188 0.000 0.000 0.874
2.15 17.2 0.300 0.694 3881.093 0.694 0.000 0.412 0.412 0.000 0.000 1.106
2.2 17.6 0.400 0.703 4391.487 0,703 0.000 0.713 0.713 0.000 0.000 1.416
2.25 18 0.500 0.711 4953.961 0.711 0.000 1.084 1.084 0.000 0.000 1.795
2.3 18.4 0.600 0.719 5572.384 0.719 1.719 1.516 1.516 0.000 0.000 2.235
2.35 18.8 0.700 0.727 6250.810 0,727 2.432 2.001 2.001 0.000 0.000 2.728
2.4 19.2 0.800 0.735 6993.485 0.735 2.978 2.528 2.528 0.000 0.000 3.263
2.45 19.6 0.900 0.743 7804.846 0.743 3.439 3.089 3.089 0.000 0.000 3.832
2.5 20 1.000 0.750 8689.533 0.750 3.845 3.673 3.673 0.000 0.000 4.424
2.55 20.4 1.100 0.758 9652.388 0.758 4.212 4.271 4.212 0.000 0.000 4.970
2.6 20.8 1.200 0.766 10698.460 0.766 4.549 4.873 4.549 0.000 0.000 5.315
2.65 21.2 1.300 0.773 11833.011 0.773 4.863 5.470 4.863 0.000 0.000 5.636
2.7 21.6 1.400 0.780 13061.520 0.780 5.158 6.052 5.158 0.000 0.000 5.939
2.75 22 1.500 0.788 14389.686 0.788 5.437 6.613 5.437 0.000 0.000 6.225
2.8 22.4 1.600 0.795 15823.432 0.795 5.703 7.143 5.703 0.000 0.000 6.498
2.85 22.8 1.700 0.802 17368.913 0.802 5.956 7.637 5.956 0.000 0.000 6.759
2.9 23.2 1.800 0.810 19032.517 0.810 6.199 8.088 6.199 0.000 0.000 7.009
2.95 23.6 1.900 0.817 20820.869 0.817 6.433 8.491 6.433 0.000 0.000 7.250
3 24 2.000 0.824 22740.837 0.824 6.659 8.844 6.659 0.000 0.000 7.483
3.05 24.4 2.100 0.831 24799.538 0.831 6.878 9.144 6.878 0.436 0.000 8.144
3.1 24.8 2.200 0.838 27004.337 0.838 7.089 9.391 7.089 1.232 0.000 9.159
3.15 25.2 2.300 0.844 29362.857 0.844 7.295 9.586 7.295 2.263 0.000 10.402
3.2 25.6 2.400 0.851 31882.981 0.851 7.495 9.731 7.495 3.484 0.000 11.830
3.25 26 2.500 0.858 34572.853 0.858 7.689 9.831 7.689 4.869 0.000 13.417
3.3 26.4 2.600 0.865 37440.891 0.865 7.879 9.894 7.879 6.401 0.000 15.145
3.35 26.8 2.700 0.871 40495.781 0.871 8.065 9.927 8.065 8.066 0.000 17.002
3.4 27.2 2.800 0.878 43746.490 0.878 8.246 9.944 8.246 9.855 0.000 18.979
3.45 27.6 2.900 0.885 47202.264 0.885 8.423 9.957 8.423 11.760 0.000 21.067
3.5 28 3.000 0.891 50872.636 0.891 8.597 9.983 8.597 13.773 0.000 23.261
3.55 28.4 3.100 0.897 54767.431 0.897 8.767 10.041 8.767 15.890 0.000 25.554
3.6 28.8 3.200 0.904 58896.767 0.904 8.934 10.153 8.934 18.105 0.000 27.943
3.65 29.2 3.300 0.910 63271.060 0.910 9.098 10.344 9.098 20.415 0.000 30.423
3.7 29.6 3.400 0.917 67901.032 0.917 9.259 10.642 9.259 22.815 0.000 32.991
3.75 30 3.500 0.923 72797.711 0.923 9.418 11.079 9.418 25.303 0.000 35.643
3.8 30.4 3.600 0.929 77972.439 0.929 9.573 11.691 9.573 27.874 0.000 38.377
3.85 30.8 3.700 0.935 83436.872 0.935 9.726 12.514 9.726 30.528 0.000 41.190
3.9 31.2 3.800 0.941 89202.988 0.941 9.877 13.591 9.877 33.261 0.000 44.080
3.95 31.6 3.900 0.948 95283.092 0.948 10.026 14.969 10.026 36.071 0.000 47.044
4 32 4.000 0.954 101689.814 0.954 10.172 16.697 10.172 38.956 0.000 50.082
BASIN Al - STAGE STORAGE
Elev AreaCff^Z) Volume (ff^S)
0 8582 0
1 9474 9028
2 10410 18970
3 11393 29871.5
4 12417 41776.5
5 13480 54725
6 14572 68751
ATTACHMENTS
Pre & Post-Developed Maps, Project Plan and Detention
Section Sketches
ONSITE PRE DEVELOPEMNET DRAINAGE AREA EXHIBIT FOR
"FAIR OAKS VALLEY" CARLSBAD, CA
GRAPHIC SCALE
DATE PREPARED
JULYS, 2012
PASCO LARET SUITER
^^^^maam & ASSOCIATES
CIVIL ENQINEERINB + UND PLANNINQ * LAND SURVEYING
535 N Gout Hlghwaj' 101 Stc A Solut Beach, CA 92075
ph B5B.259.«212 | fx B58.259.4B12 | plMenglneerlng.com
ONSITE POST DEVELOPEMNET DRAINAGE AREA EXHIBTT FOR:
"FAIR OAKS VALLEY" CARLSBAD, CA
P0C.2
(NOT MODELED)
MODELED)
(NOT MODELED)
DATE PREPARED
JULYS, 2012
3RAPHIC SCALE 1=100
100 200 300
PASCO LARET SUITER
wa^m^^^m & ASSOCIATES
CIVIL ENQINEERINB * LAND PLANNINQ + LAND SURVEYING
535 N Coiit HIghwar 101 Ste A Soiana Beach. CA 92075
ph g5B.259.B212 | fx B5B.259.4B12 | pUaenglneerlng.com
IMPERMEABLE LINER
24 GRA VEL LA YER
RISER OUTLET STRUCTURE
24" AMENDED SOIL
MIN. INFILTRATION
RA TE 5"/HR.
^ BASIN TOP ELEV
BASIN INVERT
LID INVERT
LID ORIFICE
EXIST. GROUND BIORETENTION AREA
BIORETENTION AREA CROSS SECTION (TYP)
NOT TO SCALE
RISER WALL
PVC PlPe-
INLET DEBRIS SCREEN-
MULCH LA YER
: ^ RESTRICTOR PLA TE
t
RISER WALL
FRENCH DRAIN 6"
-ORIFICE
GRA VEL STORAGE LA YER
D ^ RESTRICTOR PLA TE
-ORIFICE
RISER ORIFICE DETAIL LID ORIFICE DETAIL
NOT TO SCALE NOT TO SCALE
TO flf fHJkCEO
ON TOP
MIDDLE ORIFICES
UM/EH ORtnCES
(ORIflCE /VUMSeWS" ANO Ei£V.
POf TABLE ATTACHED. ALL
OfTff^CtS TO BE imiFORkUL Y
D/SmaUTED ALONG ALL FACES
OF RISER STRUCTURE.)
OUTLETSmUCTURE DETAIL (TYP)
NOT TO SCALE
o o o
h
n n
/
LOW
ELEV
OUTLET STRUCTURE DETAIL - SECTION (TYP)
NOT TO SCALE
GRATED TOP tllOltff'
OUTLET STRUCTURE DETAIL -PLAN (TYP)
NOT TO SCALE
BASIN LOW ORIFICE MID ORIFICE SPILLWAY
NUMBER #/DIAM ELEV (FT) #/DIAM ELEV (FT) B(FT) h(FT) H(FT)
1 8X1.5" 1 2 8X6" 4 3.1 1 5 6
ATTACHMENTS
SWMM Input Data in Input Format (Existing & Proposed Models)
[TITLE]
INPUT-Post Dev Al A2 A3 A4
[OPTIONS]
FLOW_UNITS
INFILTRATION
FLOW_ROUTING
START_DATE
START_TIME
REPORT_START_DATE
REPORT_START_TIME
END_DATE
END_TIME
SWEEP_START
SWEEP_END
DRY_DAYS
REPORT_STEP
WET_STEP
DRY_STEP
ROUTING_STEP
ALLOW_PONDING
INERTIAL_DAMPING
VARIABLE_STEP
LENGTHENING_STEP
MIN_SURFAREA
NORMAL_FLOW_LIMITED
SKIP_STEADY_STATE
FORCE_MAIN_EQUATION
LINK_OFFSETS
MIN SLOPE
CFS
GREEN_AMPT
KINWAVE
10/01/1951
00:00:00
10/01/1951
00:00:00
09/30/2008
23:00:00
01/01
12/31
0
01:00:00
00:15:00
04:00:00
0:01:00
NO
PARTIAL
0.75
0
0
BOTH
NO
H-W
DEPTH
0
[EVAPORATION]
;;Type Parameters
MONTHLY
DRY ONLY
0.041 0.076 o.iie
NO
0.192 0.237 0.318 0.308 0.286 0.217 0.14 0.067 0.041
[RAINGAGES]
Name
Oceanside
[SUBCATCHMENTS]
Name
Rain
Type
Time Snow Data
Intrvl Catch Source
INTENSITY 1:00 1.0 TIMESERIES OCEANSIDE
Raingage Outlet
Total
Area
Pent. Pent. Curb Snow
Imperv Width Slope Length Pack
Al
LID Al
Oceanside
Oceanside
LID_A1
DIVAl
25.07 49.1
0.238980716 0
580.6
10
5.45 0
0 0
[SUBAREAS]
;;Subcatchment N-Imperv N-Perv S-Imperv S-Perv PctRouted
Al
LID Al
0.012
0.012
0.05
0.05
0.02
0.02
0.1
0.1
25
25
OUTLET
OUTLET
[INFILTRATION]
;;Subcatchment Suction HydCon
Al
LID Al
0.01875 0.3
0.01875 0.3
[LID CONTROLS]
LID_A1
LID_A1
LID_A1
LID_A1
LID Al
Type/Layer Parameters
BC
SURFACE
SOIL
STORAGE
DRAIN
21.9
24
24
0.2879
4
67
5
0
0.2
0.01875
0
0.1
0.1
0
6
1.5
[LID USAGE]
INPUT-Post Dev Al A2 A3 A4
LID Process
LID Al
;;Subcatchment
LID_A1
[OUTFALLS]
;;Name
OUT_TOTAL
[DIVIDERS]
;;Name
DIVAl 0
[STORAGE]
;; Invert
;;Name Elev.
Infiltration Parameters
Number Area
1 10410
Width
0
InitSatur Fromlmprv ToPerv Report File
Invert
Elev.
Outfall
Type
Stage/Table
Time Series
Invert
Elev.
FREE
Diverted
Link
Divider
Type
BY Al
Max.
Depth
Tide
Gate
NO
Parameters
.32106 0
Init.
Depth
Storage
Curve
Curve
Params
100
Ponded Evap.
Area Frac.
BAS_A1
[CONDUITS]
Max.
; ; Name
Flow
Inlet
Node
Outlet
Node
TABULAR BASINl
Manning
Length N
Inlet
Offset
Outlet
Offset
Init.
Flow
DUM_A1
BY Al
[OUTLETS]
Flap
;;Name
Gate
DIVAl
DIVAl
Inlet
Node
OUT_TOTAL
BAS Al
Outlet
Node
Outflow
Height
0.01
0.01
Outlet
Type
Qcoeff/
QTable Qexpon
OR Al BAS Al OUT TOTAL TABULAR/DEPTH ORIFICEl NO
[XSECTIONS]
;;Link Shape Geoml Geom2 Geom3 Geom 4 Barrels
DUM_A1
BY Al
DUMMY
DUMMY
[LOSSES]
;;Link Inlet Outlet Average Flap Gate
[CURVES]
;;Name Type X--Value Y--Vail
0RIFICE3 Rating 0 0 000
ORIFICES 0 05 0 020
0RIFICE3 0 1 0 073
0RIFICE3 0 15 0 149
0RIFICE3 0 2 0 219
0RIFICE3 0 25 0 262
0RIFICE3 0 3 0 298
0RIFICE3 0 35 0 331
0RIFICE3 0 4 0 361
0RIFICE3 0 45 0 388
0RIFICE3 0 5 0 414
0RIFICE3 0 55 0 438
0RIFICE3 0 6 0 461
ORIFICES 0 65 0 482
0RIFICE3 0 7 0 503
INPUT-Post Dev Al A2 A3 A4
ORIFICES 0 75 0.523
ORIFICES 0 8 0.542
ORIFICES 0 85 0.838
ORIFICES 0 9 1.363
ORIFICES 0 95 2.037
ORIFICES 1 2.8S2
ORIFICEl Rating 0 0.000
ORIFICEl 0 05 0.022
ORIFICEl 0 1 0.079
ORIFICEl 0 15 0.142
ORIFICEl 0 2 0.178
ORIFICEl 0 25 0.208
ORIFICEl 0 3 0.234
ORIFICEl 0 35 0.258
ORIFICEl 0 4 0.279
ORIFICEl 0 45 0.299
ORIFICEl 0 5 0.318
ORIFICEl 0 55 0.336
ORIFICEl 0 6 0.S52
ORIFICEl 0 65 0.S68
ORIFICEl 0 7 0.384
ORIFICEl 0 75 0.398
ORIFICEl 0 8 0.413
ORIFICEl 0 85 0.426
ORIFICEl 0 9 0.440
ORIFICEl 0 95 0.453
ORIFICEl 1 0.465
ORIFICEl 1 05 0.478
ORIFICEl 1 1 0.490
ORIFICEl 1 15 0.501
ORIFICEl 1 2 0.513
ORIFICEl 1 25 0.524
ORIFICEl 1 S 0.535
ORIFICEl 1 35 0.545
ORIFICEl 1 4 0.556
ORIFICEl 1 45 0.566
ORIFICEl 1 5 0.576
ORIFICEl 1 55 0.586
ORIFICEl 1 6 0.596
ORIFICEl 1 65 0.606
ORIFICEl 1 7 0.615
ORIFICEl 1 75 0.62 4
ORIFICEl 1 8 0.633
ORIFICEl 1 85 0.64S
ORIFICEl 1 9 0.651
ORIFICEl 1 95 0.660
ORIFICEl 2 0.669
ORIFICEl 2 05 0.726
ORIFICEl 2 1 0.874
ORIFICEl 2 15 1.106
ORIFICEl 2 2 1. 416
ORIFICEl 2 25 1.795
ORIFICEl 2 3 2.235
ORIFICEl 2 35 2.728
ORIFICEl 2 4 S.263
ORIFICEl 2 45 S.8S2
ORIFICEl 2 5 4.424
ORIFICEl 2 55 4.970
ORIFICEl 2 6 5.315
ORIFICEl 2 65 5.636
ORIFICEl 2 7 5.939
ORIFICEl 2 75 6.225
ORIFICEl 2 8 6.498
ORIFICEl 2 85 6.759
ORIFICEl 2 9 7.009
ORIFICEl 2 95 7 .250
ORIFICEl 3 7 . 483
ORIFICEl 3 05 8.144
ORIFICEl 3 1 9.159
ORIFICEl 3 15 10.402
INPUT-Post Dev Al A2 A3 A4
ORIFICEl 3 2 11 8S0
ORIFICEl 3 25 13 417
ORIFICEl 3 3 15 145
ORIFICEl 3 35 17 002
ORIFICEl S 4 18 979
ORIFICEl 3 45 21 067
ORIFICEl 3 5 23 261
ORIFICEl 3 55 25 554
ORIFICEl 3 6 27 943
ORIFICEl 3 65 SO 423
ORIFICEl 3 7 S2 991
ORIFICEl 3 75 35 643
ORIFICEl 3 8 38 377
ORIFICEl S 85 41 190
ORIFICEl 3 9 44 080
ORIFICEl 3 95 47 044
ORIFICEl 4 50 082
0RIFICE2 Rating 0 0 000
0RIFICE2 0 05 0 026
0RIFICE2 0 1 0 097
0RIFICE2 0 15 0 198
0RIFICE2 0 2 0 292
0RIFICE2 0 25 0 349
0RIFICE2 0 3 0 398
0RIFICE2 0 35 0 441
0RIFICE2 0 4 0 481
0RIFICE2 0 45 0 517
0RIFICE2 0 5 0 551
0RIFICE2 0 55 0 584
0RIFICE2 0 6 0 614
0RIFICE2 0 65 0 643
0RIFICE2 0 7 0 671
0RIFICE2 0 75 0 698
0RIFICE2 0 8 0 723
0RIFICE2 0 85 0 911
0RIFICE2 0 9 1 234
0RIFICE2 0 95 1 644
0RIFICE2 1 2 125
0RIFICE4 Rating 0 0 000
0RIFICE4 0 05 0 033
0RIFICE4 0 1 0 126
0RIFICE4 0 15 0 268
0RIFICE4 0 2 0 447
0RIFICE4 0 25 0 649
0RIFICE4 0 S 0 804
0RIFICE4 0 35 0 912
0RIFICE4 0 4 1 008
0RIFICE4 0 45 1 259
0RIFICE4 0 S 1 639
0RIFICE4 0 55 2 102
0RIFICE4 0 6 2 631
ORIFICES Rating 0 0 000
0RIFICE5 0 OS 0 033
0RIFICE5 0 1 0 126
0RIFICE5 0 15 0 268
ORIFICES 0 2 0 447
ORIFICES 0 25 0 649
ORIFICES 0 3 0 804
ORIFICES 0 35 0 912
ORIFICES 0 4 1 008
ORIFICES 0 45 1 096
ORIFICES 0 S 1 177
ORIFICES 0 55 1 253
ORIFICES 0 6 1 325
ORIFICES 0 65 1 393
ORIFICES 0 7 1 458
ORIFICES 0 75 1 520
ORIFICES 0 8 2 134
INPUT-Post Dev Al A2 A3 A4
ORIFICES 0 85 3.205
ORIFICES 0 9 4.574
ORIFICES 0 95 6.182
ORIFICES 1 7.998
OR A7 Rating 0 0.000
OR A7 0 05 0.033
0R_A7 0 1 0.126
0R_A7 0 15 0.268
0R_A7 0 2 0.447
OR A7 0 25 0.649
0R_A7 0 3 0.804
OR A7 0 35 0.912
0R_A7 0 4 1.008
OR A7 0 45 1.096
0R_A7 0 5 1.177
0R_A7 0 55 1.253
0R_A7 0 6 1.325
OR A7 0 65 1.393
0R_A7 0 7 1.458
0R_A7 0 75 1.520
0R_A7 0 8 1.579
0R_A7 0 85 1.855
0R_A7 0 9 2.308
0R_A7 0 95 2.878
0R_A7 1 3.540
0R_A6 Rating 0 0.000
0R_A6 0 05 0.033
OR A6 0 1 0.126
0R_A6 0 IS 0.268
OR A6 0 2 0.447
0R_A6 0 25 0.649
0R_A6 0 3 0.804
0R_A6 0 35 0.912
OR A6 0 4 1.008
0R_A6 0 45 1. 096
0R_A6 0 5 1.177
OR A6 0 55 1.253
OR A6 0 6 1.325
0R_A6 0 65 1.393
0R_A6 0 7 1.458
0R_A6 0 75 1.520
OR A6 0 8 1.797
0R_A6 0 85 2.253
OR A6 0 9 2.824
0R_A6 0 95 3.488
OR A6 1 4.233
BASINl Storage 0 10414.5
BASINl 0 25 10655.4
BASINl 0 5 10899.0
BASINl 0 75 11145.0
BASINl 1 11393.6
BASINl 1 25 11644.8
BASINl 1 5 11898.6
BASINl 1 75 12154.8
BASINl 2 12413.7
BASINl 2 25 12675.1
BASINl 2 5 12939.0
BASINl 2 75 13205.5
BASINl 3 13474.6
BASINl 3 25 13746.2
BASINl 3 S 14020.4
BASINl 3 75 14297.1
BASINl 4 14576.4
BASIN3 Storage 0 921. 4
BAS IN 3 0 25 1059.1
BASIN3 0 5 1199.2
BASIN3 0 75 1341.9
INPUT-Post Dev Al A2 A3 A4
BASIN3 1 1487.0
BASIN 2 Storage 0 1542
BASIN_2 0 25 1939
BASIN_2 0 5 2336
BASIN_2 0 75 2733
BASIN_2 1 3130
BASIN4 Storage 0 1373.6
BASIN4 0 1 1544.5
BASIN4 0 2 1715.4
BASIN4 0 3 1886.3
BASIN4 0 4 2057.2
BASIN4 0 5 2228.1
BASIN4 0 6 2399
BASINS Storage 0 690
BASINS 0 25 1117.25
BASINS 0 5 1544.5
BASINS 0 7S 1971.75
BASINS 1 2399
BASIN6 Storage 0 1376.8
BASIN6 0 25 1435.5
BASIN6 0 5 1495.0
BASIN6 0 75 1555.4
BASIN6 1 1616.7
BASIN7 Storage 0 1413.9
BASIN7 0 25 1475.8
BASIN7 0 5 1538.6
BASIN7 0 75 1602.1
BASIN7 1 1666.5
[TIMESERIES]
;;Name Date Time Value
OCEANSIDE FILE "OsideRain.prn"
[REPORT]
INPUT NO
CONTROLS NO
SUBCATCHMENTS ALL
NODES ALL
LINKS ALL
[TAGS]
[MAP]
DIMENSIONS 0.000 0.000 10000.000 10000.000
Units None
[COORDINATES]
;;Node X-Coord Y-Coord
OUT_T0TAL
DIVAl
BAS_A1
5126.235
630.435
-336.957
2678.375
6978.261
6152.174
[VERTICES]
;;Link X-Coord Y-Coord
[Polygons]
;;Subcatchment X-Coord Y-Coord
Al
LID Al
619.565
630.435
8456.522
7641.304
[SYMBOLS]
;;Gage X-Coord Y-Coord
INPUT-Post Dev Al A2 A3 A4
Oceanside 7532.609 7119.565
[TITLE]
INPUT-Pre Dev Al A2 A3 A4
[OPTIONS]
FLOW_UNITS
INFILTRATION
FLOW_ROUTING
START_DATE
START_TIME
REPORT_START_DATE
REPORT_START_TIME
END_DATE
END_TIME
SWEEP_START
SWEEP_END
DRY_DAYS
REPORT_STEP
WET_STEP
DRY_STEP
ROUTING_STEP
ALLOW_PONDING
INERTIAL_DAMPING
VARIABLE_STEP
LENGTHENING_STEP
MIN_SURFAREA
NORMAL_FLOW_LIMITED
SKIP_STEADY_STATE
FORCE_MAIN_EQUATION
LINK_OFrSETS
MIN SLOPE
CFS
GREEN_AMPT
KINWAVE
10/01/1951
00:00:00
10/01/1951
00:00:00
09/30/2008
23:00:00
01/01
12/31
0
01:00:00
00:15:00
04:00:00
0:01:00
NO
PARTIAL
0.75
0
0
BOTH
NO
H-W
DEPTH
0
[EVAPORATION]
;;Type Parameters
MONTHLY 0.041 0.076 0.118 0.192 0.237 0.318 0.308 0.286 0.217 0.14 0.067 0.041
DRY ONLY NO
[RAINGAGES]
; ; Name
Oceanside
[SUBCATCHMENTS]
;;Name
Rain
Type
Time Snow Data
Intrvl Catch Source
INTENSITY 1:00 1.0 TIMESERIES OCEANSIDE
Raingage Outlet
Total
Area
Pent.
Imperv Width
Pent.
Slope
Curb Snow
Length Pack
Al Oceanside OUT TOTAL 24 . 07 582 10
[SUBAREAS]
;;Subcatchment N-Imperv N-Perv S-Imperv S-Perv PetZero RouteTo PctRouted
Al 0.012 0.05 0.02 0.1 25
[INFILTRATION]
;;Subcatchment Suction HydCon
Al
[OUTFALLS]
;;Name
Invert
Elev.
0.025
Outfall
Type
IMDmax
0.3
Stage/Table
Time Series
Tide
Gate
INPUT-Pre Dev Al A2 A3 A4
OUT_TOTAL 0 FREE NO
[TIMESERIES]
;;Name Date Time Value
OCEANSIDE FILE "OsideRain.prn"
[REPORT]
INPUT NO
CONTROLS NO
SUBCATCHMENTS ALL
NODES ALL
LINKS ALL
[TAGS]
[MAP]
DIMENSIONS 0.000 0.000 10000.000 10000.000
Units None
[COORDINATES]
;;Node X-Coord Y-Coord
OUT_TOTAL 5982.437 3095.499
[VERTICES]
;;Link X-Coord Y-Coord
[Polygons]
;/Subcatchment X-Coord Y-Coord
Al 663.043 7391.304
[SYMBOLS]
;;Gage X-Coord Y-Coord
Oceanside 7532.609 7119.565
ATTACHMENT 7
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,
outfalls, storage units, weir 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 typical values found in technical literature (such as Maidment's Handbook of
Hydrology). Recommended values for the SWMM model have been obtained from the
"Review and Analysis of Dan Diego County Hydromodification Management Plan (HMP):
Assumptions, Criteria, Methods, & Modeling Tools, May 2012" prepared by TRWE for the Cities
of San Marcos, Oceanside and Vista, and also used as guidance for other North County Cities
(Poway, Escondido, Encinitas and Carlsbad). The document follows initial analyses laid out by
Orange County criteria established for their SWMM calibration plus additional regional
analyses. Currently, no recommended values have been established by the San Diego County
HMP Permit for the SWMM Model.
Soil characteristics of the existing soils were determined from the site specific geotechnical
report or USDA Survey Analysis. 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
Ht Edt Vmm Prafvct Ibport Took WMBW IWp
""SI
TiUe>fJot«
Opium
Cfmatdogy
•: Hydi«iicE
L- Curva*
Time Patterns
MepLabeb
Zoom Level: 10(K ^ X.Y: 379.583.10142,700
Ran Gage Oceanside Q
Propetty lvalue
Name |(Ilceanside
X-Cootdinate
Y-Coordinate 7111565
Description
Tag
Rain Format ilNTENSITY
Time Interval Il:0O
Snow Catch Facto/1.0
Data Source TIMESERIES
TIME SERIES:
- Series Name j OCEANSIDE
D.",TAFILE:
- File Name
• Station ID
- Rain Units IN
User-assigned name of rain gage
Outfol OUT TOTAL
Property Value
Name OUT_TOTAL
X-Coordinate 598Z437
Y-Coordinate 3095.4»
Description
Tag
Inflows NO
Treatment NO
Invert El. 0
Tide Gate NO
Type FREE
1 Fixed Outfall
Fixed Stage 0
1 Tidal Ouifall
Curve Name »
1 Time Series; OuHair
Series Name *
User-assigned name of outfall
Sui
Property Value
Name Al
X-Coordinate ^3.043
Y-Coordinate 7331T304
Description
Tag
Rain Gage Oceanside
Outlet OUrfOTAL
Area 2407
Width 582
% Slope 10
% Imperv 0
N-Imperv 0.012
N-Perv 005
Dstore-I mperv 0.02
Dstote-Perv 0.1
^ero-l mperv
Subarea Routing OUTLET
Percent Routed 100
Infiltration 6REEN_AMPT
Groundwater NO
Snow Pack
LID Controls io
i Land Uses
Initial Buildup INONE
Curb Length 0
U set-assigned name of subcatchment
, ....... . .. .... ...
Infiltration Editor
Infiltration Method i GREEN.AtvlPT
Property lvalue
Suction Head
Conductivitii 0.025
Initial Deficit 0.3
Soil capillary suction head (inches or mm)
-
POST-DEVELOPED CONDITION
File Edit Wcw PniKt Report Tools Window Hdf
-- Title/Nolet
Opbont I
•matolois' jl
'J Hydn^ |!
Ram Gages i
Subcalchmerts f
. Aqufets
•- Snow Packs |
: Un« Hydogtaphs I
• LIDContFok I
^ Hydraulics |
• i^t Nodes I
Drvidefs I
Stoiage Units i
. S Lnkt j
' Conhob !
LV Qualty I
TmSefW)
Time Patterns |
:-'MapLabels |
H
Flow Units. CFS ZoomLevetlOOS X.Y: 8441,273.9879,254
OutfeH OUT.TOTAL
Property lvalue
Name |OUT_TOTAL
X-Coordinate
Y-Coordinate 2678.375
Description
Tag
llnflows NO
Treatment NO
i Invert El, :o
Tide Gate NO
Type FREE
Fi;-:ed Outfall
Fixed Stage 0
Tidal Ouffall
Curve Name
Time Series Oulfall
Series Name
User-assigned name of outfall
R«n Gage Oceanside
Property Value
Name Oceanside
X-Coordinate 7532.609
Y-Coordinate 7119.565
Description
Tag
Rain Format INTENSITY
Time Interval 1:00
Snow Catch Factor 1 -0
Data Source TIMESERIES
TIME SERIES;
- Series Name OCEANSIDE
DATA FILE:
- File Name
• Station ID
• Rain Units IN
User-assigned name of rain gage
Subcatehment Al B|
Property Value
Name All
X-Cootdinate
Y-Coordinate 8456,522
Descri|3tion
Tag
Rain Gage Oceanside
Outlet LID_A1 ,
Area 25,07'
Width 580,G
1 % Slope 5,45
Z Imperv 49.1
N-Imperv dm 2
N-Perv Vi.m
Dstore-I mperv 0.02
Dstore-Perv 01
XZero-l mperv
Subarea Routingj OUTLET
Percent Routed iS
Infiltration GREEN_AMPT
Groundwater NO
. Snow Pack
LID Controls |o
Land Uses jo
Initial Buildup INONE
Curb Length [o"
f User-assigned name of subcatchment
Subcatchment UD Al
Property Value
Name iUD Al
X-Coordinate B30.435
Y-Coordinate 7641.304
Description
Tag
Rain Gage Oceanside
Outlet DIVAl
Area 0.238980716
Width 10
X Slope 0
% Imperv 0
N-Imperv OOl 2
N-Perv 0.05
Dstote-I mperv 0.02
Dstore-Perv 0.1
^ero-l mperv ^25'
Subarea Routing OUTLET
Percent Routed KM
Infiltration GREEN^AMPT
Groundwater NO
Snow Pack
LID Controls
Land Uses 0
Initial Buildup 'NONE
Curb Length
User-assigned name of subcatchment
Infilmtion Editor
Infiltration Method !6REEN_AMPT
Property Value
Suction Head 9
Conductivity
Initial Deficit 03
EXPLANATION OF SELECTED VARIABLES
Sub Catchment Areas:
Please refer to the attached diagrams that indicate the DMA and Bio-Retention (BR) sub areas modeled
within the project site at both the pre and post developed conditions draining to the POC.
Parameters for the pre- and post-developed models include soil type D in accordance with the
geotechnical investigation undertaken for the project site (attached at the end of this appendix).
Suction head, conductivity and initial deficit corresponds to average values expected for soils type D,
according to sources consulted, professional experience, and approximate values obtained by the
interim Orange County modeling approach.
TRWE selected infiltration values, such that the percentage of total precipitation that becomes runoff, is
realistic for soil type D and slightly smaller than measured values for Southern California watersheds.
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.
Sub-catchment BR:
The area of bio-retention must be equal to the area of the development tributary to the bio-retention
facility (area that drains into the bio-retention, equal external area plus bio-retention itself). Five (5)
decimal places were given regarding the areas of the bio-retention to insure that the area used by the
program for the LID subroutine corresponds exactly with this tributary.
UD Usage Editor
Control Name
Number of Replicate Units
Area of Each Unit (sq ft or sq m)
X of Subcatchment Occupied
Top Width of Overland Flow
Surface of Each Unit (ft or m)
% Initially Saturated
X of Impervious Area Treated
10410
100.0
0 "
100
DMA LIDS
liD Control Editor .. . .
^ :
Control Name.
LID Type: Bio-Retention Cel
Process Layers:
Surface Soil j Storage Underdrain]
Storage Depth
(in. or mm)
21.9
Vegetatbn Volume
Fraction
0
Surface Roughness
(Mannings n)
0
Surface Slope
(percent)
UD Control Editor
Control Name:
LID Type:
Process Layers:
Bio-RetentipnCell
OK Cancel
Surface j SoU Storage Underdrair)]
Height
(in. or mm)
24^'"^^^
Void Ratio
(VoidsSolids
0^67
Conductivity
(in/hr or mm/hr)
Clogging Factor
Note: use a Conductivity of 0 if the LID
unit has an impermeable bottom.
LiD Control Editor
Control Name:
LID Type:
Process Layers:
Biofletention Cel
Surface Soil Storage | Underdrain |
Thickness 24
(in. or mm)
Porosity
(volume fraction)
Field Capacity
(volume fraction)
Wilting Point
(volume fraction)
Conductivity
(in/hr or mm/hr)
Conductivity Slope
Suction Head
(in. or mm)
0.4
UD Control Editor
Control Name:
UD Type:
Process Layers:
Bio-Retention Cell
Surface | Soil | Storage |L)nderdrain
0^79
0.5
Drain Coefficient
(in/hr or mm/hr)
Drain Exponent
Drain Offset Height
(in. or mm)
Note: use a Drain Coefficient of 0 if the
LID unit has no underdrain.
OK Cancel
LID Control Editor: Explanation of Significant Variables
Storage Deptti:
The storage depth variable within the SWMM model is representative of the storage volume
provided beneath the engineered soil and mulch components of the bioretention facility.
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.
TRWE considers such a value to be slightly high; however, in order to comply with the HMP
Permit, the value recommended by the Copermittees for the porosity of amended soil is 0.4,
per Appendix A of the Final Hydromodification Management Plan by Brown & Caldwell, dated
March 2011. Such porosity is equal to the porosity of the gravel per the same document.
Void Ratio: The ratio of the void volume divided by the soil volume is directly related to
porosity as n/(l-n). As the underdrain layer is composed of gravel, a porosity value of 0.4 has
been selected (also per Appendix A of the Final HMP document), which results in a void ratio of
0.4/(1-0.4) = 0.67 for the gravel detention layer.
Cloaaing 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, and instead, a
conservative value of infiltration was recommended.
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:
q = CiH- (1)
where q is the peak flow in in/hr, n is the exponent (typically 0.5 for orifice equation), Hp 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:
Q=lLr£L 2g^JlzIlol (2)
^ 4 5 144 12 ^ '
where Q is the peak flow in cfs, D is the diameter in inches, Cg is the typical discharge coefficient
for orifices (0.61-0.63 for thin walls and around 0.75-0.8 for thick walls), g is the acceleration of
gravity in ft/s^ and H and HD are defined above and are also used in inches in Equation (2).
Divider CXVAl
Property Value
Name DIVAl
X-Coordinate 830.435
Y-Cootdinate G978.261
Description
Tag
Inflows NO
Treatment NO
Invert El. 0
Max. Depth 0
Initial Depth 0
Surcharge Depth 0
Ponded Area 0
Diverted Link BY_A1
Type CUTOF
Cutoff Divider
Cutoff Flow .32106
Tabular Divider
Curve Name |"
Vv'eir Divider
Min. Flow 0
Max. Depth 0
Coefficient
Discharge coefficient for a WEIR divider
Cutoff Flow: This is the only significant variable in the diversion, as the type of diversion is
defined by this value. Any excess of flow over this value will be diverted into a pond subroutine
(the surface stage of the bio-retention basin) and routed there. The determination of this value
equates to the value obtained with equation (2) (displayed in the Drain Coefficient section of
this attachment) plus 1%, when H = depth of gravel layer and Hp = 0 (orifice situated at the
datum). Thus, once flows exceed the maximum discharge the LID orifice experiences when soils
are saturated (the storage depth full), ponding occurs within the bioretention basin, routing
these additional flows via the pond riser.
Note: The complete storage and rating curves and the respective explanation is shown at the end of this
appendix. A variable area vs. elevation storage curve was used for the final model, and a discharge that is a
function of the outlet structure in the surface was used also.
Storage tint BAS.Al
Property [Value
Name iBAS_A1
X-Coordinate ;-336.357
Y-Coordinate '6152.174
Description
Tag
Inflows iNO
Treatment INO
Invert El.
Max. Depth 14 •
Initial Depth io" '
Ponded Area
Evap. Factor
Infiltration |NO
Storage Curve ifASULAR
Functional Curve^
Coefficient 1000
Exponent 0
Constant iO
Tabular Curve
Curve Name iBASINI
User-assigned name of storage unit
Outlet OR.Al gj
Property lvalue
Name iOR Al
i —
Inlet Node ;BAS_A1
Outlet Node i0UT_T0TAL
Description
Tag
Inlet Offset io
Flap Gate :N0
Rating Curve TABUUliR/'DEPTH
Functional Curve 1
Coefficient '10.0
Exponent jo.5
Tabular Curve |
Curve Name ORIFICEl
Storage Curve Editor
Curve Name
BASINl
Description
:
Rating Curve Editor
Curve Name
ORIFICE 1
Description
Head
m
Outflow
(CFS)
1 0 0.000
2 0.05 0.022
3 0.1 0.073
4 0.15 0,142
5 0.2 0.178
6 0.25 0.208
7 03 0.234
8 0.35 0258
9 0.4 0.279
Depth
(ft)
Area
[ft2) • -
1 0 10414.5
2 0.25 10655.4
3 0.5 10899i0 -
4 0.75 11145.0 '
5 1 11393^6 " i
6 1.25 11644.8 j
7 1.5 11898.6
8 1.75 12154.8
9 2 12413.7 -
Al
LID Al
BAS AI
OR Al
OUT TOTAL
Al
OUT_TOTAL
ATTACHMENTS
Geotechnical Justification of Soil Type D Conditions
i 400 •iet.otvQ
OZ o cu
"I
o o-
CO
< W
fD =
2.'<
c
3
CD
o o
117- 13' 19"
2
3660600
n
o
w g
O
S
01 =>
™ o
>
o
8 117" 12-50"
Hydrologic Soil Group-San Diego County Area, California
(Fair Oaks Valley)
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Map Units
Soil Ratings
• A
• A/D
• B
• BID
• C
• CIO
• D
Not rated or not available
Political Features
0 Cities
Water Features
Streams and Canals
Transportation
-HM- Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Map Scale: 1 ;4,760 if printed on A size (8.5" "11") sheet.
The soil surveys that comprise your AOI 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 accurate map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL: http://websoilsurvey.nrcs.usda.gov
Coordinate System: UTM Zone 11N NAD83
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
Sun/ey Area Data: Version 6, Dec 17, 2007
Date(s) aerial images were photographed: 6/7/2005
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.
USDA Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
8/23/2012
Page 2 of 4
Hydrologic Soil Group-San Diego County Area, California Fair Oaks Valley
Hydrologic Soil Group
Hydrologic Soil Group— Summary by Map Unit — San Diego County Area, Califomia (CA638)
Map unit symbol Map unit name Rating Acres in AOI Percent of AOI
AwC Auld clay, 5 to 9 percent slopes D 4.2 5.3%
ExG Exchequer rocky silt loam, 30 to 70
percent slopes
D 3.2 4.0%
SnG San Miguel-Exchequer rocky silt
loams, 9 to 70 percent slopes
D 72.2 90.6%
Totals for Area of Interest 79.6 100.0%
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 (A/D, BID, and CID). 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 (A/D, BID, or CID), 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 H/lethod: Dominant Condition
USDA Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
8/23/2012
Page 3 of 4
Hydrologic Soil Group-San Diego County Area, Califomia Fair Oaks Valley
Component Percent Cutoff: None Specified
Tie-break Rule: Higher
Natural Ftesourcss Web Soil Survey 8/23/2012
Conservation Service National Cooperative Soil Survey Page 4 of 4
ATTACHMENTS
Summary Files from the SWMM Model
Pre Dev Al A2 A3 A4
EPA STORM WATER MANAGEMENT MODEL - VERSION 5.0 (Build 5.0.022)
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
Snowmelt NO
Groundwater NO
Flow Routing NO
Water Quality NO
Infiltration Method GREEN_AMPT
Starting Date OCT-01-1951 00:00:00
Ending Date SEP-30-2008 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
**************************
Runoff Quantity Continuity
**************************
Total Precipitation
Evaporation Loss
Infiltration Loss
Surface Runoff
Final Surface Storage ....
Continuity Error (%)
**************************
Flow Routing Continuity
**************************
Dry Weather Inflow
Wet Weather Inflow
Groundwater Inflow
RDII Inflow
External Inflow
External Outflow
Internal Outflow
Storage Losses
Initial Stored Volume ....
Final Stored Volume
Continuity Error (%)
Volume
acre-feet
Depth
inches
1352 .654 674 360
50 . 361 25 107
1054 .901 525 916
270 .630 134 921
0 .000 0 000
-1 .718
Volume Volume
acre-feet 10^6 gal
0 000 0 000
270 630 88 189
0 000 0 000
0 000 0 000
0 000 0 000
270 630 88 189
0 000 0 000
0 000 0 000
0 000 0 000
0 000 0 000
0 000
Subcatchment Runoff Summary
Pre_Dev_Al_A2_A3_A4
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
Al 674.36 0.00 25.11 525.92 134.92 88.18 26.10 0.200
Analysis begun on: Thu Sep 13 12:15:54 2012
Analysis ended on; Thu Sep 13 12:16:07 2012
Total elapsed time: 00:00:13
Post Dev Al A2 A3 A4
EPA STORM WATER MANAGEMENT MODEL - VERSION 5.0 (Build 5.0.022)
t************* t******************
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.
**************************************************^ Ir ***** *
****************
Analysis Options
****************
Flow Units CFS
Process Models:
Rainfall/Runoff YES
Snowmelt NO
Groundwater NO
Flow Routing YES
Ponding Allowed NO
Water Quality NO
Infiltration Method GREEN_AMPT
Flow Routing Method KINWAVE
Starting Date OCT-01-1951 00:00:00
Ending Date SEP-30-2008 23:00:00
Antecedent Dry Days 0.0
Report Time Step 01: 00 00
Wet Time Step 00: 15 00
04: 00 00
Routing Time Step 60. 00 sec
WARNING 04: minimum elevation drop used for Conduit DUM_A1
WARNING 04: minimum elevation drop used for Conduit BY Al
**************************
Runoff Quantity Continuity **************************
Total Precipitation
Evaporation Loss
Infiltration Loss
Surface Runoff
Final Surface Storage ....
Continuity Error (%)
Flow Routing Continuity **************************
Dry Weather Inflow
Wet Weather Inflow
Groundwater Inflow
RDII Inflow
External Inflow
External Outflow
Internal Outflow
Storage Losses
Initial Stored Volume ....
Final Stored Voliame
Continuity Error (%)
Volume
acre-feet
Depth
inches
1422 .280 674 360
128 .384 60 872
529 .525 251 069
776 .634 368 233
0 .000 0 000
-0 .8 62
Volume Volume
acre-feet 10^6 gal
0 000 0 000
776 607 253 069
0 000 0 000
0 000 0 000
0 000 0 000
775 038 252 558
0 000 0 000
1 375 0 448
0 000 0 000
0 000 0 000
0 025
Post Dev Al A2 A3 A4
**********************************
Highest Flow Instability Indexes
*** + *** + ***********•**•**•*•***•****•
All links are stable.
IT**********
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
***************************
Subcatchment Runoff Summary
t********* t ***** *
Subcatchment
Total
Precip
in
Total
Runon
in
Total
Evap
in
Total
Infil
in
Total
Runoff
in
Total
Runoff
10^6 gal
Peak Runoff
Runoff Coeff
CFS
Al
LID Al
674.36
674.36
0.00
39772.77
51.23
1072.84
248.29
542.58
379.14
38997.32
258.09 29.13 0.562
253.06 29.09 0.964
^************* *********
LID Performance Summary *r******il
Pent.
Error
Subcatchment LID Control
Total
Inflow
in
Evap Infil Surface Drain Init. Final
Loss Loss Outflow Outflow Storage Storage
in
LID_A1
-0.41
LID Al 40447.13 1072.88 542.60 12712.34 26286.41
******************
Node Depth Summary ******************
Average Maximum Maximum Time of Max
Depth Depth HGL Occurrence
Node Type Feet Feet Feet days hr:min
OUT_TOTAL OUTFALL 0.00 0.00 0.00 0 00:00
DIVAl DIVIDER 0.00 0.00 0.00 0 00:00
BAS_A1 STORAGE 0.01 3.61 3.61 18823 17:16
Post Dev Al A2 A3 A4
Node Inflow Summary *******************
Maximum Maximum Lateral Total
Lateral Total Time of Max Inflow Inflow
Inflow Inflow Occurrence Volume Volume
Node Type CFS CFS days hr:min 10^6 gal 10"6 gal
OUT_TOTAL OUTFALL 0.00 28 . 90 18823 17:16 0.000 252.539
DIVAl DIVIDER 29.09 29.09 18823 17:15 253.050 253.050
BAS_A1 STORAGE 0.00 28.77 18823 17:15 0.000 85.979
**********************
Node Surcharge Summary **********************
Surcharging occurs when water rises above the top of the highest conduit.
Node Type
Max. Height Min. Depth
Hours Above Crown Below Rim
Surcharged Feet Feet
DIVAl
BAS Al
DIVIDER
STORAGE
499679.02
499679.02
0.000
3.613
0.000
0.887
*r********
Node Flooding Summary
*******^ *******
No nodes were flooded.
******** *r*********
Storage Volume Summary
******** ***********
Storage Unit
BAS Al
Average
Volume
1000 ft3
Avg ESI
Pent Pent
Full Loss
Maximum
Volume
1000 ft3
Max
Pent
Full
Time of Max
Occurrence
days hr:min
Maximum
Outflow
CFS
0.103 44.212 18823 17:15 28.57
***************^
Outfall Loading Summary
********** 1:********
Outfall Node
OUT_TOTAL
System
Flow
Freq.
Pent.
Avg.
Flow
CFS
Max.
Flow
CFS
Total
Volume
10"6 gal
5.96
5.96
0.32
0.32
28 . 90
28 .90
252.539
252.539
Link Flow Summary **********************
Post Dev Al A2 A3 A4
Link Type
Maximum Time of Max Maximum Max/ Max/
I Flow I Occurrence |Veloc| Full Full
CFS days hr:min ft/see Flow Depth
DUM_A1
BY_A1
OR Al
DUMMY 0.32 90 03:27
DUMMY 28.77 18823 17:15
DUMMY 28.57 18823 17:16
******** t*********
Conduit Surcharge Summary *************************
Conduit
Hours Full
Both Ends Upstream Dnstream
Hours Hours
Above Full Capacity
Normal Flow Limited
DUM_A1
BY Al
0.01
0.01
0.01
0.01
0.01 499679.02
0.01 499679.02
0.01
0.01
Analysis begun on:
Analysis ended on:
Total elapsed time:
Tue Sep 11 15:22:57 2012
Tue Sep 11 15:23:23 2012
00:00:26