HomeMy WebLinkAboutCT 14-08; LOT 9 WESTIN HOTEL AND TIMESHARE; ADDENDUM TO STORM WATER QUALITY MANAGEMENT PLAN (SWQMP) AND DRAINAGE STUDY; 2017-04-17Addendum to Storm Water Quality Management Plan (SWQMP)
and Drainage Study due to Construction Plans Revision No. 2
FOR
LOT 9 DEVELOPMENT, WESTIN HOTEL AND TIMESHARE
CT 14-08
ECE VE
2
DWG 496-2A
SWQMP NO. 16-29
ENGINEER OF WORK:
ROBERT D. DENTINO
RCE 45629
PREPARED FOR:
GRAND PACIFIC DEVELOPMENT, INC.
5900 PASTEUR CT. SUITE 200
CARLSBAD, CA92008
(760)431-8500
PREPARED BY:
ltl!~I
ENGINEERING
EXCEL ENGINEERING
440 STATE PLACE
ESCONDIDO, CA 92029
(760)745-8118
DATE:
April 17, 2017
LAND DEVELOPMENT
ENCi ': -~ING
RECORD COPY
Jl}f--(.pl '2.~J '7
Initial Date
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Declaration of Responsible Charge
I hereby declare that I am the engineer of work for this project. That I have exercised responsible charge
over the design of the project as defined in section 6703 of the business and professions codes, and that
the design is consistent with current design. I understand that the check of the project drawings and
specifications by the City of Carlsbad is confined to a review only and does not relieve me, as engineer of
work, of my responsibilities for project design.
ENGINEER OF WORK
Excel Engineering
440 State Place
Escondido, CA 92029
Tel -(760)745-8118
Fax-(760)745-1890
Project Number: 13-070
Robert ~ntino, RCE 45629
Registration Expire: December 31, 2018
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Introduction:
On October 26, 2016, Excel Engineering submitted the SWQMP and Drainage Study for the Lot 9 Westin
Hotel and Timeshare project. Since then, there have been changes in the Grading Plans (Revision 2 of
DWG 496-2A} that have modified both aforementioned reports; this addendum addresses the affected
calculations.
SWQMP Summary of Changes:
1.} BMP-2 is a biofilter with an impermeable liner (BF-1} that drains to Outfall POC-D (see Attachment
A). Previously, the gravel layer for BMP-2 was 18 inches, with a 3 inch gravel layer below the perforated
pipe. To resolve a conflict between the perforated pipe and outlet pipe inverts, the gravel layer was
revised to 15 inches with a 3 inch later below the perforated pipe (see dimension "D" on Attachment B)
and the perforated pipe invert was raised to 236.50 (see BMP-2 detail on Attachment C). These
adjustments had the following updates to the SWQMP:
POC-D Flow Duration Curves (see Attachment D):
Flow Duration Pre-Dev.= 365 days x 24 hr/day x 0.204% = 17.9 hours
Flow Duration Mitigated Post-Dev. (revised 18" storage)= 365 days x 24 hr/day x 0.091%=8.0 hours
Flow Duration Mitigated Post-Dev. (previous 21" storage)= 365 days x 24 hr/day x 0.090%=7.8 hours
From the results above, we can see that the flow duration, with the revised 18 inch gravel storage, has
increased slightly compared to the previous 21 inch gravel depth, however, it is less than the duration of
the Pre-Development. Therefore, this gravel depth change is acceptable.
SWMM Calculations (see Attachment E):
For Outfall D (POC D), the gravel depth was revised from 21 inches (including 3" invert elevation offset)
to 18 inches (including 3" elevation offset). This change does not increase the outflow, and the flow
duration and peak return period are still within the range of passing criteria.
Worksheet 8.5-1 (see Attachment F):
The "Aggregate storage above underdrain invert" (Row 13} for BMP-2 shows the correct 15" layer.
2.) Per the previously submitted Drainage Study, BMP-2 has two (2) upper orifices at an elevation of
239.75 and a bottom pond elevation of 239.25, resulting in 6" above the biofilter surface (see
Attachment G, taken from the approved Drainage Study). In the previous SWMM calculations, the
surface ponding is the "berm height' and the correct 6" was used. However, the Grading Plans had an
incorrect value of 4.2" and has since been revised to match the calculations (see dimension "B" on
Attachment B). The "Surface Ponding" (Row 11) for BMP-2 on Worksheet B.5-1 (see Attachment F) has
also been corrected.
3.) The "Aggregate storage above underdrain invert" (Row 13} of Worksheet B.5-1 (see Attachment F)
has been revised to for BMP-1, BMP-3, BMP-4 and BMP-5 to match the correct "D" values from
Attachment B. BMP-1, BMP-3 and BMP-4 values were corrected from 15 inches to 18 inches, and BMP-
5 from 6 inches to 9 inches.
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4.) In the SWMM calculations, the parameters below are already correct. In the LID editor, the gravel
depths are the same as the "D" values from Attachment B, plus 3 inches. Offset height was set to 3
inches in the LID editor under "drain" section for all biofilters. The following table summarizes the
underdrain coefficients used for each of the BMP units and translates the C factor coefficient to an
equivalent round orifice diameter based on 1/16th inch increments:
* 'iii
GI * ·5 ;§ E * '.; ..... * "' C:-.:-Ill ::: 0 * * I C: -.:-C: C: z GI o-tl ~ I * 3: :5. 3: 3: :5. 3: .., u Ill ~ ~ 0 GI 0 0 GI 0 Ill e ~ GI C: J!! ~ "C u "C "C "" "C u c.. <( u iD u 't: ·5 ~ ·5 i ~ £ ~ .:-3: Ill ~ .:' .Q 0 ~ ,-t ::, ~ ~ c5 ::, 0 ~ :a 0 VI VI ... ::, "' :::::; :::::; ::::i I-I-I-C: GI Q VI 0 :5. 0 t;; 0 :5.
BMP-2 BMP-2 374.01 8 0.223 6 18 18 0.4 0.67 4.5 6.7 13.9 25.1
BMP-4 BMP-4 763 8 0.109 10.8 18 21 0.4 0.67 15.4 12.9 31.2 59.5
BMP-1 BMP-1 908.01 8 0.089 9.6 18 21 0.4 0.67 16.9 15.8 38.3 71
The character* in the column heading indicates that the values was read directly from the SWMM inp file.
Assume: orifice coefficient Co= 0.60, void ratio for surface= 1.0, centroid of underdrain orifice is located at h=O
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C
111111
'
1111 -
Drainage Study Summary of Changes:
PRIVATE STORM DRAIN LINE A
Stormdrain Line A is located southwest of the center of the proposed Westin Hotel Courtyard. Line A
conveys stormwater from the central courtyard through area drains and BMP-1, and then drains south
and then east around Villa 80 to the final outfall Dor POC-D. Portions of Line A were relocated to have
the entire storm drain line north of the property line.
PRIVATE STORM DRAIN LINE B
Stormdrain Line Bis located east of Villa 80, close to the east entrance. Line B conveys stormwater from
the central courtyard through area drains and BMP-1, and then to the east and confluence with Line A
to outfall D. The revision includes replacing the existing 24" pipe with new pipe. This was done to
accommodate the removal required to rebuild the easterly slope in conjunction with the construction of
the Keystone walls. In addition, a concrete encasement will be provided around the 30° vertical bend
fitting of the new 24" pipe to mitigate the velocity due to the pipe's steep slope.
PRIVATE STORM DRAIN LINE E
Stormdrain Line E is located south of the proposed Villa 80, adjacent to the building entrance from the
cul-de-sac to Villa 80. Line E conveys stormwater from the Villa 80 roof drain system, per architectural
plans, to a detention pipe, to BMP-3 and then to the outfall C. The changes include extending
stormdrain Line E-7 so that Line E-8 is not in conflict with the landscaping tree roots at the parking stall
island.
PRIVATE STORM DRAIN LINE F
Stormdrain Line Fis located southwest of the proposed Westin Hotel. Line F conveys flow from biofilter
basin BMP-5 and its overflow. The Grading Plans previously incorrectly showed 18" HDPE detention pipe
for SD Lines F-4 and F-5. According to the previous SWMM calculations, this detention pipe needs to be
42" with a specific flow control plate installed inside the cleanout box to detain the flow for
hydromodification purposes. A detail of this orifice plate is provided in the revised grading plans.
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E
ATTACHMENTS
-ATTACHMENT A
-·~
- ------------
.-
POC-0
·"·· •• '!" .. ,.· • .. ,.• / ·. ,• . .. . . . .. .
'
Fig.3c. -SWM M Post-Developmellt w ith Mitigation Model for POC D
Oceao5"idlo-SI067
lg
-RI --- - --m;;;I ----ATIACHMENT B
I r Pie cu,w a;, w/
SUi'FA(I l1JO!Pli'Nl Ali'£A I
r ltN. f1f« [N() CAP SEE f't.AN l1EW APli'CW FC¥i' ~r
as51!'AllW
l!N;NC £l)(;[' ANCIKR PO? ~ 0£TM 8ElOW
~ ~ L _J
_}, ~l7IN£ABI£ I.JNCN ()(k:..~ A/If. PCIM) lAflf)
......_fliw. SPCCFICATW ar LINER ffR sae
ENCINIIRS N£Ca41'MNDA lla'IS I
l)(S!M'CE ~ ,er (Y I ( sa;r1·~r QVERFlOW s":;::l:!l()V) E,rp (Y(? Afl'i\'.lll "bf ~~!'&I SI.OP£ !IJ LINEii \ r.:tl. AMI Jl/11/V!ENANCE BASIN ENEJrr;Y Pl.AN ~ ~ ACCESS !KSSIPA TCW
[a;~~ FS EI£Y PUN ~ I ~1c ffli' RANI \. + l:c j3 "'
"I .. ..... I~ . . L )fflQaf,,Bn9klfflW:ftliRril~
,--· ~ ~fl{ JIW. s /4
. JVIIR fll.lNAllOti·
•RA,C·,
"· -r oo::io fllOtll Ct¥rB Ct/! f()
f)f£S1CIV£ f'tf'£ 600f cw cOIAVAl.£/VT ro ScAL PYl'c ff'Nt"fRA!ION
flfKOll6H MlfflUfOIIS
UV£N
I ~ l Q/UlfZ SHWA~ 1
1· PEA Ql'A ifZ fK. !ER
~
BUP ./
BMP -1
BMP -2
BMP -J
BMP -4
BMP -5
I
I t! ______ _
ENSVRE A !IGH f SEAL
B£!11£EN LJNOl AA'O
OITT?lFO#' Sl1?//C!l/lr£
SVRFAC£
FOOTPRINT
(SOFT)
9.Jl. 0
374.0
1955.0
75J.O
2f6.0
A1 A2
(INCH) {INCH}
16.0 18.0
1ao 120
21.2 JO.O
16.0 18.0
,ao 120
~
o
0
o
0
obo
0
o
0
o
lOttEli' IJl?IIJC£
PU!£
-POV'ONA !£0 Pff FIOI/Lfo£
LA t(li'. aASS 2 -(
1'£/r!,1£Aa.£ P£R ~ .WAN.S' S1'£C 64-1.25
J• "1N Ql'Al{l ~ JlfN/JIUII ,t" OIAll£ffR 8£1.()#l l'tJff/JKA Tl:O '-80lll:l,/ (Y
Prl?f7:RA!Ell Plff COIJPACIIIJ sot BASIN 1./NOcli'OR /IIIV
CATCHBASIN ANO BIOFll.!NAllON BASIN [)(TA/£
N()T fO SCAlE
BOX RISER / ORIFICES SIZES
8 C D OVERROW
STRUCTURE (INCH} (INCH) {INCH) DIA/JETER SIZE LOltf:R UPP£R (INCHES) (INCH)
_!.6_ -18.0 _ tRI'> _ J6xJ6 (2) AT 6# 0.500 , y ,( "
6.0 18.0 ~ 15.0 /A-1 J6xJ6 (2) AT 1r 0.500 ,_. 1.8 -..... T (2) AT 6H 18.0 ll!.U J6xJ6 0.500
,o.o 18.0 18.0 J6x.Jo (2) AT 8~ 0.500
4.9 18.0 9.0 J6x36 (2) AT 12~ 0.500
/J.IPERJ.IEABLE
l/NER?
YES
YES
YES
YES
YES
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ATTACHMENT C
BMP-2
\\
SI) LINE A
SEE SHEET /0
--\ ~ \ -
' ' ' ' '\. '-1. ',
TOP OF BASIN ELEV. = 240.25 rs OF BASIN ELEV. = 239.25 ' I .,., .........._
I I • .,.
--/
- -ATTACHMENT D
0.8
0.6 -J!?
.!:. 0.4
Q) -n,
0::
~ 0 .2
0
LL
o.o
-0.2
- - - - -- - - -- - -
POC-D
Flow Duration Curves
--Pre Developmenl
T 010 (0.856cfs)
Post Development Mitigated
-,IE-Qlf (0.0636c(S)
. . . . . . . . . . . . . . . ~ . .. . . . . . . . . . .
-0) q
0
Flow Duration Pre0evelopmenr-365(days)x.24(hr/day)x0 204(%),.17 .9(hours/year)
Flow Duration M1uoated Post Devetopmem::365(days)x24{hr/day)x0.091(%):r.8.0(hours/year)
0.00 0 .05 0.1 0
(o/o) Percent Time Exceedance
~ ......... .
0 .15
-.:t 0 "' 0
0.20
-
r·"t •• r,
ATTACHMENT E .. .. .. -..
[TITLE:]
;; POC D -POST-DEVELOPMENT WITH MITIGATION
[OPTIONS]
; ;Option Value
FLOW_UNITS CFS
INFILTRATION GREEN_AMPT
FLOW_ROUTING KINWAVE
LINK_OFFSE:TS DEPTH
MIN_SLOPE 0
ALLOW_PONDING YES
SKIP_STE:ADY_STATE: NO
START_DATE: 08/01/1951
START_TIME 16:00:00
REPORT_START_DATE 08/01/1951
REPORT_START_TIME: 16:00:00
END_DATE 05/23/2008
END_TIME 23:00:00
SWEEP_START 01/01
SWE:EP_E:ND 12/31
DRY_DAYS 0
REPORT_STEP 01:00:00
WET_STEP 01:00:00
DRY_STEP 01:00:00
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 12.557
MAX_TRIALS 8
HEAD_TOLERANCE 0.005
SYS_FLOW_TOL 5
LAT_FLOW_TOL 5
MINIMUM_STEP 0.5
THREADS 1
[EVAPORATION]
; ; Data Source Parameters
MONTHLY
DRY_ONLY
0.06
NO
0.08 0.11 0.15
[RAINGAGES]
; ;Name Format Interval SCF
0.17 0.19
Source
-..
0.19 0.18
-------
0.15 0 .11 0.08 0.06
INPUT FILE -POC-D POST-DEVELOPMENT WITH HYDROMODIFICATION MITIGATION
WESTIN LOT9
Page 1 of4
-F""I
r, F'''W .. r, r·1
Oceanside-SID67 INTENSITY 1:00
Oceanside IN
[ SUBCATCHMENTS]
; ;Name Rain Gage
--..
1. 0 FILE
Outlet Area
---------
"R: \SWMM model \Rain gage dat \ALERT station at Oceanside (Sensor ID 6 7) . dat"
%Imperv Width %Slope CurbLen SnowPack
;;------------------------------------------------------ --------------------------------
BMP-2 Oceanside-SID67 POC-D 0.008586 0 24.08 0.5 0
BMP-4 Oceanside-SID67 POC-D 0.017516 0 17.42 0.5 0
BMP-1 Oceanside-SID67 POC-D 0.020845 0 28.83 0.5 0
DMA-2.1 Oceanside-SID67 BMP-2 0.1265 77 217.4 2 0
DMA-2.2 Oceanside-SID67 BMP-2 0.02785 100 25.54 2 0
DMA-2.3 Oceanside-SID67 BMP-2 0.07775 77 141.7 2 0
DMA-4.4 Oceanside-SID67 BMP-4 0.13 100 159.5 2 0
DMA-4.3 Oceanside-SID67 BMP-4 0.190356 100 180 2 0
DMA-4.2 Oceanside-SID67 BMP-4 0.0975 37.35 193 2 0
DMA-4.1 Oceanside-SID67 BMP-4 0.039 46.4 170 2 0
DMA-1.1 Oceanside-SID67 DMA-1.2 0.011846 100 23.45 2 0
DMA-1. 2 Oceanside-SID67 BMP-1 0.0769 39.15 159.6 2 0
DMA-1.3 Oceanside-SID67 BMP-1 0.2625 100 197 2 0
DMA-1. 4 Oceanside-SID67 BMP-1 0.04899 74.6 147 2 0
[SUBAREAS]
;;Subcatchment N-Imperv N-Perv S-Imperv S-Perv Pct Zero RouteTo PctRouted
;;---------------------------------- -------------------- ------------------------------
BMP-2 0.012 0.1
BMP-4 0.012 0.1
BMP-1 0.012 0.1
DMA-2.1 0.012 0.1
DMA-2.2 0.012 0.1
DMA-2.3 0.012 0.1
DMA-4.4 0.012 0.1
DMA-4.3 0.012 0.1
DMA-4.2 0.012 0.1
DMA-4.1 0.012 0.1
DMA-1.1 0.012 0.1
DMA-1.2 0.012 0.1
DMA-1.3 0.012 0 .1
DMA-1.4 0.012 0 .1
[INFILTRATION]
;;Subcatchment Suction Ksat
'' BMP-2 9 0.01875
BMP-4 9 0.01875
BMP-1 3.0 0.15
DMA-2.1 9 0.01875
DMA-2.2 9 0.01875
DMA-2.3 9 0.01875
DMA-4.4 3.0 0.15
DMA-4.3 9 0.01875
0.05 0.1
0.05 0.1
0.05 0.1
0.05 0.1
0.05 0.1
0.05 0.1
0.05 0.1
0.05 0.1
0.05 0.1
0.05 0.1
0.05 0.1
0.05 0.1
0.05 0.1
0.05 0.1
IMD
0.33
0.33
0.31
0.33
0.33
0.33
0.31
0.33
25
25
25
25
25
25
25
25
25
25
25
25
25
25
OUTLET
OUTLET
OUTLET
OUTLET
OUTLET
OUTLET
OUTLET
OUTLET
OUTLET
OUTLET
OUTLET
OUTLET
OUTLET
OUTLET
INPUT FILE -POC-D POST-DEVELOPMENT WITH HYDROMODIFICATION MITIGATION
WESTIN LOT9
Page 2 of4
IP'I r-1
. .,, P'I P'II
DMA-4.2
DMA-4.1
DMA-1.1
DMA-1.2
DMA-1. 3
DMA-1.4
[LID_CONTROLS]
; ;Name
BMP-1
BMP-1
BMP-1
BMP-1
BMP-1
BMP-2
BMP-2
BMP-2
BMP-2
BMP-2
BMP-4
BMP-4
BMP-4
BMP-4
BMP-4
., .. ~
9 0.01875
9 0.01875
9 0.01875
3.0 0.15
3.0 0.15
3.0 0.15
Type/Layer Parameters
--------
BC
SURFACE 9.6
SOIL 18
STORAGE 21
DRAIN 0.089
BC
SURFACE 6
SOIL 18
STORAGE 18
DRAIN 0.223
BC
SURFACE 10.8
SOIL 18
STORAGE 21
DRAIN 0.109
-
0.33
0.33
0.33
0. 31
0. 31
0. 31
0
0.4
0.67
0.5
0.0
0.4
0.67
0.5
0.0
0.4
0. 67
0.5
[LID_USAGE]
;;Subcatchment LID Process Number Area
BMP-2
BMP-4
BMP-1
BMP-2
BMP-4
BMP-1
[OUTFALLS]
; ;Name Elevation Type
POC-D 0
[REPORT]
;;Reporting Options
INPUT NO
CONTROLS NO
SUBCATCHMENTS ALL
NODES ALL
LINKS ALL
[TAGS]
FREE
1
1
1
374.01
763.00
908.01
Stage Data
--
0 0
0.2 0.1
0 0
3 6
0 0
0.2 0 .1
0 0
3 6
0 0
0.2 0.1
0 0
3 6
Width
0
0
0
Gated
NO
-
InitSat
0
0
0
5
5
5
5
5
5
Route To
-------
5 1. 5
5 1. 5
5 1. 5
Fromlmp ToPerv RptFile DrainTo
0
0
0
0
0
0
INPUT FILE -POC-D POST-DEVELOPMENT WITH HYDROMODIFICATION MITIGATION
WESTIN LOT9
Page 3 of4
.. I'' 1
r·1 r,
[MAP]
-lllci • r, r~, r. .. -
DIMENSIONS 6237542.230 1992281.828 6238164.250 1992642.002
Uni ts Feet
[SYMBOLS]
; ;Gage X-Coord
Oceanside-SID67 6238037.879
[BACKDROP]
Y-Coord
1992601. 214
.. --------
FILE "Q:\13\13070\gpip\gp2\Storm\SWMM\swmrn calcs\OUTFALL C\Background2.jpg"
DIMENSIONS 6237666.773 1992317.518 6238030.238 1992677.692
INPUT FILE -POC-D POST-DEVELOPMENT WITH HYDROMODIFICATION MITIGATION
WESTIN LOT9
Page 4 of 4
-..
- - -
c:1 - - --- -- -ATTACHMENT F
EYAl,UATION Of SOIL INFILTRATION RATE RESTRICTED BY LOWER ORIFICE ---·1 IM,-2 -·3 --4 IM,-s
l Pondin1 --ht (in) 9.6 6.0 7.8 10.8 4.9
2 Bk>retentlon Soil Layer (In, 18 18 18 18 18
3 Grovel • -r lin) 21 18 21 21 12
4 TOTAi. (Unel+Une2+Une31 {In) 49 42 47 so 35
5 TOTAi. ((Line 4)/12) (It) 4.1 3.5 3.9 4.2 2.9 --6 Orifice Coefficient (<al 0.60 0.60 0.60 0.60 0.60
7 Low Fk>w Orifice Oiilmeter (in) I o.so I o.so I o.so o.so I o.so I
8 Drain el(J)onent 0.5 I 0.5 I 0.5 I 0.5 I 0.5 --9(Flow lute (volumetric) (cfs) I 0.013 I 0.012 o.013 I 0.013 I 0.011
Undonlrlin Flow llou ,_, Unit ArH
10 Pondina Oeoth Surface Area (sqlt) 760.86 431.66 939.92 361.06 86.78
11 8ioretention Surface Acea lsaltl 937.00 374.00 1956.00 763.00 216.00
12 Bioretention Surface Area ((Une 11)/(4356011 lac! 0.0215106 0.008S8S9 0.0449036 0.0175161 0.0049587
13 Porosity of Bk>retentlon Soll 0.40 0.40 0.40 0.40 0.40
14 Flow Rate•-unit areal HUne 91 / tune 13 • Une 11 • 12 • 360011 fin/hr) 1.5189846 35363183 0.7139794 1.8883914 5.5797904
15 Effective Pondln, Oeoth fin) 8.70 6.46 5.77 7.96 3.45
16 Pondi111 Oepth • Vwo,-(ln) 9.6 6.00 7.80 10.80 4.92
17 OJtoff Flow (cfs) 0.01318 0.01225 0.01293 0.01334 0.01116
18 filtration rote lin/hrl 0.61 1.41 0.29 0.76 2.23
RECAI.CUlATE WORKSHEET 1.5-1: IIASEO ON LOWER ORIFICE FLOW RATE Slmple.....,._lor ___ 8MP·l BMP-2 8MP·3 BMP-4 BMP-5
I Remainina OCV alter lrnolementini retention BMPs (cubic feet) 759 373 11196 753 288 ---2 Infiltration rate from Worksheet 0.5-1 If panlal infiltratk>n Is feasible (In/hr) 0.00 0.00 0.00 0.00 0.00
3 ADowable drawdown time fOf au.rH.ate st~e below the underdrain (hrs~ 36 36 36 36 36
4 IDooth of runaff that can be inroltrated (Une2J<Uno3) (in) 0.00 0.00 0.00 0.00 0.00
S IA.uregate pore space 0.4 0.4 0.4 0.4 0.4
6 Required depth of 2ravel below the underdraln (Une4/Une5) (In) 0 0 0 0 0
7 Assumed surface area of biomentlon 8MP (sa·lt) 582 316 716 185 47
8 Media ret>ined pare Sl)ace (in/in) 0.1 0.1 0.1 0.1 0.1
9 Volume retained by 8MP (Une4+(Llne12xUne8)1/12'Llne7 (cubic feet) 87 47 107 28 7
10 OCV that requires biofttention (Linel-Unt9) (cubic feet) 671 326 1788 725 281
-PARAMETIIIS
11 Surface Pondinc ( 6° min / 12" max) 9.6 6 7.8 10.8 4.9
12 Media Thickness (18 Inches minimum( 18 18 18 18 18
13 l.u•re,iate stor11e above undetdrain invert (12" tvo!ul) 1, : IE
14 medio avallablo pare Sl)OCO (in/lnl 0.2 0.2 0.2 0.2 0.2
15 Medi, filtration rate (in/hr) 5.00 5.00 5.00 5.00 5.00
!Sa MOOIFIEO -nitration based on lower orifice (ln/hrl 0.61 1.41 0.29 0.76 2.23
!Sb Filtrotlon rate to be used for sllin& (•Min(line lS, line lSa)) (in/hr) 0.61 1.41 0.29 0.76 2.23 ......... ~
16 Alowa~e Routina Time for sitlna (hours} 6 6 6 6 6
17 Oepth filtered durin& the storm (line 15b x line 16((1nches) 4 8 2 5 13
18 Oepth of Oetention Stor,,ce (line ll+(line 12ldine14)+Cline 13JCline5)1 20 16 19 22 12
19 Total depth treated (line 17+tine 18) 24.05 24.09 20.31 26.13 25.51
OPTION 1-IIIOA£T(N'fl()N 1.5 TIMES THE DCV
20 Required biorottered volume (1.5xline10) (cubic feet) 1007 489 2682 1088 422
21 Required fooq,rint (line 20/line 191•12 (square feet) S03 243 1585 500 198
OPTION-2-5tan 0.75of-DCV In_ and__,.
22 Required Storaae (surfac.,pores) volume (0.75xline101 (cubic·leet) 504 244 1341 544 211
23 Required footprint (line 22/line 18)x12 296 188 865 302 209
FOOTPfllNT OF TIil mwi,
24 Area dralnln1 to the 8MP (sq·ltl 17404 10110 53174 19986 11705
25 Adjusted Runaff Factor for dra.,..e area (Refer to Appedix 8.1 and 8.2) 0.87 0.74 0.71 0.75 0.49
26 Minimum BMP Footprint (Line 24xLlne 2Sx0.03] 455 224 1137 452 173
27 Footprint of the 8MP • Maximum (Minlmum(llne 21, Line 23), Line 26) 455.2 223.9 1137.3 451.8 198.4
28 8MP area provided in th~ project 937.00 374.00 1956.00 7'3.00 216.00
CN<lllotY--1--lorNo--l
29 calculate the fraction of the OCV retained by the 8MP (Line 9 / Une l] N/A N/A N/A N/A N/A
30 Minimum required fraction of DCV retained for Dirtia, Infiltration condition 0.375 0.375 0.375 0.375 0.375
31 Is the retained OCV > 0.375? ~ tho answer is "NO" Increase Line 26 until "YES" N/A N/A N/A N/A N/A
I
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ATIACHMENTG
Pond No 4 BMP 2 -. M-,,-1 ;N-..i.~i~hE~•r;-e.,•:,,!. • ., .... :.o : ... !J~ 4:.·~o • .:..i:.::<••· . . . c~. ;..i~ :J ,.. . .... / IJ ~ ~ a ti:. R ci.1.~-,.m1t~
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Pond No. 4 • BMP 2
Pond Data
Pond 1torA9" l1 .,.,.d on u:sw-deflnttd v•lues
Stage I Storage Table
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2~025
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(A) (BJ
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Span (In) = 1200 000
No 8•"e4• • 1 0
lnYM1 El fftj 23• 10 000
L111t¢,Cft} ~ 66 00 000
~rr.l -oso 000
N-Val ... • 013 013
Onfice Codi. • 060 060
Multl-S1ate • n,·a Ht!
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Stage f Storage I Diacharge Table
SLOJ119' Elev.«lon Clv A
wft ft d.J
0.00
(CJ [PrfRsr)
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12 00 000 CrHLl:L(n)
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1 00
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0.00
104.:
0.00
412
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• 333 3 3)
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