RUNOFF REDUCTION VOLUME, WATER QUALITY VOLUME AND STREAM CHANNEL PROTECTION SIZING CALCULATIONS

RUNOFF REDUCTION VOLUME, WATER QUALITY VOLUME AND STREAM CHANNEL PROTECTION SIZING CALCULATIONS UWMS 130 PINES BRIDGE ROAD TOWN OF NEW CASTLE WESTCHESTER COUNTY, NY JMC Project: 5043 Drawing Reference: DA-1, DA-2 Computed by: Checked by: SS DV Date Printed: 4/17/2012

Water Quality Volume (WQ v ) & Water Quality Peak Flow (Q p ) NEW YORK STATE DEPARTMENT OF ENVIRONMENTAL CONSERVATION JMC Project No: 5043 Unified Stormwater Sizing Criteria (See section 4.1,8.1b) Computed By: SS Project: UWMS MASJID & ISLAMIC CENTER Checked BY: DV Location: 130 PINES BRIDGE ROAD NEW CASTLE, NY Sheet: 1of 1 Date: 12/23/08 Dwg, Ref: DA-2 Revision Date: 04/16/12 D E S I G N P A R A M E T E R S FORM SYMBOL UNITS PDA-1A PDA-1B PDA-1C PDA-2A PDA-2B TOTAL DEVELOPED AREA MAST.tab A acres 4.71 0.86 0.35 1.893 0.51 EXISTING IMPERVIOUS AREA (only alternative practice) MAST.tab I E acres 0.40 0.00 0.00 0.00 0.38 PROPOSED IMPERVIOUS AREA MAST.tab I P acres 0.10 0.67 0.35 0.26 0.00 90% RAINFALL EVENT NUMBER (See Figure 4.1) MAST.tab P inches 1.30 1.30 1.30 1.30 1.30 PRO-TIME OF CONCENTRATION (Use TR-55 equations) MAST.tab T c hours 0.27 0.08 0.08 0.20 0.22 WQv STANDARD PRACTICE (only alternative practice) SP % 0% 0% 0% 0% 0% D E S I G N C A L C U L A T I O N S WATER QUALITY VOLUME CALCULATION (Section 4.1) PRACTICE NAME SEE ABOVE OTHER GROUP INFIL. BASIN INFIL. BASIN WET SWALE OTHER GROUP SMP SELECTION MATRICES (See above table) SEE ABOVE O-G I-2 I-2 O-2 O-G PERCENTAGE PERMANENT POOL SEE ABOVE PPP % 0% 0% 0% 0% 0% PERCENTAGE FOREBAY PRETREATMENT POOL SEE ABOVE PFP % 0% 25% ROOF 10% 0% TOTAL WATER QUALITY VOLUME WQ v =3630*P(0.05*A+0.9*I) WQ v acres-ft 0.035 0.070 0.036 0.036 0.003 TOTAL WATER QUALITY VOLUME WQ v =3630*P(0.05*A+0.9*I) WQ v cu. ft. 1,536 3,065 1,578 1,564 121 TOTAL WQv VOLUME PROVIDED EXDT.tab WQ v cu. ft. N/R 6,747 4,290 N/R PERMANENT POOL REQUIRED Vpool=WQv*PPP V pool cu. ft. 0 0 0 PERMANENT POOL VOLUME PROVIDED PV.tab V pool cu. ft. 0 0 3,273 FOREBAY PRETREATMENT REQUIRED Vpret=WQv*PFP V pret cu. ft. 766 0 156 FOREBAY PRETREATMENT PROVIDED PV.tab V pret cu. ft. 4,114 0 171 WATER QUALITY PEAK FLOW CALCULATION (Appendix B.2) RUNOFF VOLUME IN INCHES Q=WQ v /(A*3630) Q inches 0.98 1.24 0.23 CN=1000/(10+5*P+10*Q-10(Q 2 +1.25*Q*P) ½ ) CN 96.90 99.44 81.41 CN ROUNDED CN 97 99 81 CN < or = 98 CN 97 98 81 INITIAL ABSTRACTION I a =200/CN-2 I a inches 0.06 0.04 0.47 RATIO R=I a /P R 0.05 0.03 0.36 C 0 = A*R 2 +B*R +C C 0 2.47 2.47 2.35 C 1 = A*R 2 +B*R +C C 1-0.49-0.48-0.49 C 2 = A*R 2 +B*R +C C 2-0.18-0.19-0.12 UNIT PEAK DIS. qu=10^(c 0 +C 1 *Log(T c )+C 2 *(log(t c )) 2 ) q u cfs/mi 2 /in 616.02 591.53 423.73 WATER QUALITY PEAK FLOW Q p =qu*a*q/640 Q p cfs 0.81 0.40 0.29 ALTERNATIVE PRACTICE FOR PRETREATMENT (Chapter 9) WATER QUALITY PEAK TREATMENT FLOW PROVIDED Q p P cfs 1.10 N/R N/A WQ VOLUME PROVIDED WQp=640*3600*Q P P/qu WQ P cu. ft. 4,114 COMPANY CDS MODEL PRODUCT CDS2020 QUANTITY 1 APPROX. SIZE L' x W' or DIAMETER ft. 6

RUNOFF REDUCTION VOLUME WORKSHEET JMC Project: 5043 Design Points: 1 & 2 UWMS Drainage Areas: 1B, 1C & 2A Total Water Quality Treatment Volume Initial Water Quality Volume WQ V 6,207 Adjusted Water Quality Volume WQ V 6,207 Minimum Runoff Reduction Volume Design Storm [90% Rainfall Event Number] or [1-yr Storm Depth] P 1.3 In Total Area of new Impervious Cover Aic 1.29 Ac Hydrologic Soil Group (HSG) Specific Reduction Factor S 0.33 Runoff Volume [0.05 + 0.009 x %I] R V 0.95 Impervious Cover targeted for Runoff Reduction [S x Aic] Ai 0.43 Ac TOTAL VOLUME Required [ = (P x R V x Ai) / 12] 1,908 Runoff Reduction Techniques (Volume) GREEN INFRASTRUCTURE PRACTICE / SMP SYMBOL VALUE UNITS Infiltration Basin #1B 11,466 Vegetated Swale #2A-1 137 Vegetated Swale #2A-2 184 TOTAL 11,787 Runoff Reduction Is Total > Adjusted WQ V? Is Total > Minimum? YES YES Date Printed: 4/17/2012

VEGETATED SWALE WORKSHEET Vegetated Swale #2A-1 JMC Project: 5043 Design Point: 2 Drainage Area: 2A-1 Site Data for Drainage Area to be Treated by Practice Design Storm [90% Rainfall Event Number] P 1.3 In Impervious Area I 0.20 Ac Area A 0.37 Ac Percent Impervious %I 52.66 % Runoff Volume [0.05 + 0.009 x %I] R V 0.52 TOTAL VOLUME Required [WQ V = (P x R V x A) / 12] WQ V 916 Design Storm [1-yr Storm Depth] P In TOTAL VOLUME Required (TMDL) [WQ V = 1-yr Storm Runoff] WQ V Design Parameters Water Quality Volume WQ V 916 Water Quality Flow Rate Q WQ 0.27 S 10 Year Storm Flow Rate Q 10 1.32 S Channel Design Given/Assumed Information Channel Longitudinal Slope S 4.00 % Channel Bottom Width W 4.00 Ft Channel Depth D 1.25 Ft Channel Side Slope (Hori./Verti.) z 3 Determine WQv Flow Depth & Velocity WQv Flow Depth Q WQ h 0.17 Ft Manning's Coefficeint (varying with flow depth see fig L.1) n 0.15 Water Quality Flow Rate in Channel Q 0.42 S Velocity of Q V=Q/(D*(z*D+W) V 0.04 FPS Determine Channel Length WQv Minimum Detention Time t 5 min. Length of Swale Required L=v*t*60 l 13 Ft Length of Swale Provided L 200 Ft Determine Q 10 Flow Depth & Velocity Peak Discharge Q 10 (TR-55 10 year storm) Q 10 1.32 S Peak Discharge Q 10 Depth Q 10 h 0.32 Ft Q 10 Free Board Provided f 0.93 Ft Minimum Depth of Swale Required h 0.82 Ft Total Depth of Swale Provided H 1.25 Ft Velocity of Q 10 V 10 =Q 10 /(Q 10 h*(z*q 10 h+w) V 10 0.82 FPS Runoff Reduction 20% Runoff Reduction of Required WQv in HSG A and B 183 10% Runoff Reduction of Required WQv in HSG C and D 92 15% Runoff Reduction of Required WQv in HSG C Modified* 137 12% Runoff Reduction of Required WQv in HSG D Modified* 110 *Modifications must be in accordance with Soil Restoration Standards Date Printed: 4/17/2012

VEGETATED SWALE WORKSHEET Vegetated Swale #2A-2 JMC Project: 5043 Design Point: 2 Drainage Area: 2A-2 Site Data for Drainage Area to be Treated by Practice Design Storm [90% Rainfall Event Number] P 1.3 In Impervious Area I 0.18 Ac Area A 0.63 Ac Percent Impervious %I 28.68 % Runoff Volume [0.05 + 0.009 x %I] R V 0.31 TOTAL VOLUME Required [WQ V = (P x R V x A) / 12] WQ V 919 Design Storm [1-yr Storm Depth] P In TOTAL VOLUME Required (TMDL) [WQ V = 1-yr Storm Runoff] WQ V Design Parameters Water Quality Volume WQ V 919 Water Quality Flow Rate Q WQ 0.21 S 10 Year Storm Flow Rate Q 10 0.91 S Channel Design Given/Assumed Information Channel Longitudinal Slope S 3.50 % Channel Bottom Width W 4.00 Ft Channel Depth D 1.25 Ft Channel Side Slope (Hori./Verti.) z 3 Determine WQv Flow Depth & Velocity WQv Flow Depth Q WQ h 0.17 Ft Manning's Coefficeint (varying with flow depth see fig L.1) n 0.15 Water Quality Flow Rate in Channel Q 0.39 S Velocity of Q V=Q/(D*(z*D+W) V 0.04 FPS Determine Channel Length WQv Minimum Detention Time t 5 min. Length of Swale Required L=v*t*60 l 12 Ft Length of Swale Provided L 110 Ft Determine Q 10 Flow Depth & Velocity Peak Discharge Q 10 (TR-55 10 year storm) Q 10 0.91 S Peak Discharge Q 10 Depth Q 10 h 0.27 Ft Q 10 Free Board Provided f 0.98 Ft Minimum Depth of Swale Required h 0.77 Ft Total Depth of Swale Provided H 1.25 Ft Velocity of Q 10 V 10 =Q 10 /(Q 10 h*(z*q 10 h+w) V 10 0.69 FPS Runoff Reduction 20% Runoff Reduction of Required WQv in HSG A and B 184 10% Runoff Reduction of Required WQv in HSG C and D 92 15% Runoff Reduction of Required WQv in HSG C Modified* 138 12% Runoff Reduction of Required WQv in HSG D Modified* 110 *Modifications must be in accordance with Soil Restoration Standards Date Printed: 4/17/2012

INFILTRATION WORKSHEET Site Data for Drainage Area to be Treated by Practice JMC Project: 5043 Design Point: 1 Infiltration Basin #1B Drainage Areas: 1B &1C Design Storm [90% Rainfall Event Number] P 1.3 In Impervious Area I 1.03 Ac Area A 1.21 Ac Percent Impervious %I 84.65 % Runoff Volume [0.05 + 0.009 x %I] R V 0.81 TOTAL VOLUME Required [WQ V = (P x R V x A) / 12] WQ V 4,643 Design Storm [1-yr Storm Depth] P In TOTAL VOLUME Required (TMDL) [WQ V = 1-yr Storm Runoff] WQ V Water Quality Volume Provided 2 Year Storm Entering System from PDA-1B & PDA-1C Q 2 IN 12,740 2 Year Storm Exiting System Q 2 OUT 0 Runoff Volume Infiltrated 12,740 Runoff Reduction 90% of WQ V Infiltrated 11,466 Date Printed: 4/17/2012

Water Quality Volume (WQ v ) & Water Quality Peak Flow (Q p ) for Vegetated Swale Calculations NEW YORK STATE DEPARTMENT OF ENVIRONMENTAL CONSERVATION Unified Stormwater Sizing Criteria (See section 4.1) RAINFALL DISTRIBUTION TYPE III (R=I a /P) C i =A*R 2 +B*R+C A B C Coefficients for the equation unit peak C 0-1.774 0.3301 2.4577 " Coefficients for the equation unit peak C 1 1.8622-0.7397-0.4627 Coefficients for the equation unit peak C 2-0.0648 0.2276-0.1932 D E S I G N P A R A M E T E R S SYMBOL UNITS PDA-2A-1 PDA-2A-2 TOTAL DRAINAGE AREA A acres 0.37 0.63 EXISTING IMPERVIOUS AREA (only alternative practice) I E acres 0.00 0.00 PROPOSED IMPERVIOUS AREA I P acres 0.20 0.18 90% RAINFALL EVENT NUMBER (See Figure 4.1) P inches 1.30 1.30 PRO-TIME OF CONCENTRATION (Use TR-55 equations) T c hours 0.08 0.24 D E S I G N C A L C U L A T I O N S WATER QUALITY VOLUME CALCULATION (Section 4.1) TOTAL WATER QUALITY VOLUME WQ v =3630*P(0.05*A+0.9*I) WQ v cu. ft. 915 918 WATER QUALITY PEAK FLOW CALCULATION (Appendix B.2) RUNOFF VOLUME IN INCHES Q=WQ v /(A*3630) Q inches 0.68 0.40 CN=1000/(10+5*P+10*Q-10(Q 2 +1.25*Q*P) ½ ) CN 92.79 86.96 CN ROUNDED CN 93 87 CN < or = 98 CN 93 87 INITIAL ABSTRACTION I a =200/CN-2 I a inches 0.15 0.30 RATIO R=I a /P R 0.12 0.23 C 0 = A*R 2 +B*R +C C 0 2.47 2.44 C 1 = A*R 2 +B*R +C C 1-0.52-0.53 C 2 = A*R 2 +B*R +C C 2-0.17-0.14 UNIT PEAK DIS. qu=10^(c 0 +C 1 *Log(T c )+C 2 *(log(t c )) 2 ) q u cfs/mi 2 /in 694.45 520.18 WATER QUALITY PEAK FLOW Q p =qu*a*q/640 Q p cfs 0.27 0.21

Type... Master Network Summary Page 2.01 Name... Watershed File... S:\2005\5043\PONDPACK\2012-04-16_SS\5043-PDA-VEGETATED SWALES.ppw MASTER DESIGN STORM SUMMARY Network Storm Collection: Westchester Coun Total Depth Rainfall Return Event in Type RNF ID ------------ ------ ---------------- ---------------- 10 5.0000 Synthetic Curve TypeIII 24hr MASTER NETWORK SUMMARY SCS Unit Hydrograph Method (*Node=Outfall; +Node=Diversion;) (Trun= HYG Truncation: Blank=None; L=Left; R=Rt; LR=Left&Rt) Max Return HYG Vol Qpeak Qpeak Max WSEL Pond Storage Node ID Type Event cu.ft Trun hrs cfs ft cu.ft ----------------- ---- ------ ---------- -- --------- -------- -------- ------------ PDA-2A-1 AREA 10 4790 12.1000 1.32 PDA-2A-2 AREA 10 3884 12.2000.91 *WET SWALE JCT 10 8675 12.1000 2.14 S/N: Bentley Systems, Inc. Bentley PondPack (10.01.04.00) 9:40 AM 4/18/2012

STREAM CHANNEL PROTECTION VOLUME Cp v NEW YORK STATE DEPARTMENT OF ENVIRONMENTAL CONSERVATION Unified Stormwater Sizing Criteria (See Section 4.4 & Appendix B.2) RAINFALL DISTRIBUTION TYPE III (R=I a /P) C i =A*R 2 +B*R+C A B C Coefficients for the equation unit peak C 0-1.774 0.3301 2.4577 Coefficients for the equation unit peak C 1 1.8622-0.7397-0.4627 Coefficients for the equation unit peak C 2-0.0648 0.2276-0.1932 D E S I G N P A R A M E T E R S SYMBOL UNITS PDA-1B & 1C PDA-2A TOTAL DEVELOPED AREA A acres 1.21 1.89 RAINFALL EVENT (1-year recurrence, 24-hr. duration) P 1 inches 2.80 2.80 RUNOFF CURVE NUMBER (proposed) CN 94.00 70.00 TIME OF CONCENTRATION (Use TR-55 equations) T c hours 0.08 0.24 D E S I G N C A L C U L A T I O N S CHANNEL PROTECTION VOLUME, (Cp v ) ((see Section 4.4 and Appendix B) INITIAL ABSTRACTION I a =(200/CN)-2 I a inches 0.128 0.857 RATIO R=I a /P 1 R 0.05 0.31 C 0 = A*R 2 +B*R +C C 0 2.47 2.39 C 1 = A*R 2 +B*R +C C 1-0.49-0.51 C 2 = A*R 2 +B*R +C C 2-0.18-0.13 UNIT PEAK DIS. q u =10^(C 0 +C 1 *Log(T c )+C 2 *(log(t c )) 2 ) q u cfs/mi 2 /in 613.11 459.48 RUNOFF (TR-55) Q=((P 1 -I a )^2)/(P 1 +4*I a ) Q inches 2.16 0.61 PEAK DISCHARGE Q p1 =q u *A*Q (TR-5 1 year storm) Q p1 cfs 2.50 0.82 RATIO of out/in flow (q o /q i )=14.121*q u^(-0.9703) (q o /q i ) 0.03 0.04 (V s /V r )=0.682-1.43*(q o /q i )+1.64*(qo/qi) 2-0.804*(qo/qi) 3 (V s /V r ) 0.64 0.63 HYG RUNOFF VOLUME V r =Q*A*3630 (TR-55 1year) V r cu. ft. 9,490 4,164 acres-ft 0.22 0.10 REQUIRED STORAGE VOLUME Vs=(Vs/Vr)*V r (Cpv) Vs cu. ft. 6,106 2,630 acres-ft 0.14 0.06 Provided Runoff Reduction Volume RRv 11,787 0 Net Channel Protection Volume Required 0 2,630 STORAGE VOLUME PROVIDED EXDT.tab (Cp v ) cu. ft. 0 2,902 AVERAGE RELEASE Q avg =V s /(24hr*3600sec) Q avg cfs 0.07 0.03 MAXIMUM RELEASE Q max =2*Q avg Q max cfs 0.14 0.06 *According to Section 4.4 of NYS Stormwater Management Design Manual, the CPv requirement does not apply if the reduction of the entire CPv is achieved through green infrastructure or infiltration systems. The infiltration system infiltrates enough runoff into the ground to meet the entire CPv requirement for the site, however the wet swale outlet control structure is also designed to provide CPv.

DESIGN OF OUTLET CONTROL STRUCTURE ORIFII FOR EXTENDED DETENTION OF WATER JMC Project No: 5043 QUALITY & STREAM CHANNEL PROTECTION VOLUMES Computed By: SS Checked BY: DV Project: UWMS Dwg, Ref: DA-1, DA-2 DESIGN PARAMETERS SYMBOL UNITS SUB AREA NAME PDA-2A DRAINAGE AREA A acres PRACTICE DESIGNATION O-2 PRACTICE NAME Wet Swale PERCENTAGE PERMANENT POOL REQUIRED PPR % 50% PERCENTAGE PERMANENT POOL PROVIDED PPP 100% PERCENTAGE FOREBAY PRETREATMENT POOL PFR % 10% PERCENTAGE FOREBAY PRETREATMENT POOL PROVIDED PFP 0% TOTAL WATER QUALITY VOLUME REQUIRED WQvr cu. ft. 1,564 PERMANENT POOL REQUIRED Vpool=WQv*PPP VR pool cu. ft. 782 PERMANENT POOL VOLUME PROVIDED VP pool cu. ft. 4,290 PRETREATMENT REQUIRED Vpret=WQv*PFP VR pret cu. ft. 156 PRETREATMENT PROVIDED BY VEGETATED SWALES VP pret cu. ft. 321 ELEVATION PERMANENT POOL (orifice inv. above permanent pool) E 1 (ft.) 578.62 Elev. Ext. Det. for rest of WQv (Use E-Q-V from PondPack at Volume WQVR) E 2 (ft.) 578.62 EXTENDED DETENTION ELEV. PROVIDED (rounded UP) E 2P (ft.) 578.62 DESIGN WATER QUALITY ORIFICE (See Section 8.2 Step 6.) VERIFY IF IS ENOUGH PERMANENT POOL PROVIDED OKAY VERIFY IF IS ENOUGH FOREBAY POOL PROVIDED OKAY EXTENDED DETENTION VOLUME REQUIRED EDvr=WQvr-VRpool-VRpret ED VR (cfs) 626 EXTENDED DETENTION VOLUME PROVIDED (to be) EDvp=WQvp-VPpool EDvp cu. ft. 0 AVERAGE DISCHARGE (to be release in 24 hr) Q 0 =ED VP /(24hr*3600sec) Q 0 (cfs) 0.00000 AVERAGE HEAD WATER QUALITY H 0 =(E 2 -E 1 )/2 H 0 (ft.) 0.00 ORIFICE DIAMETER CALCULATION D 0 =6.166*Q 0.5 0.25 0 /H 0 D 0 (in.) 0 ORIFICE DIAMETER ROUNDDOWN @ 1/8) D W (in.) 0 ORIFICE DIAMETER PROVIDED (suggested less than calculated) D W (in.) 1 3/8 AVERAGE HEAD PROVIDED H W =(Q 0 /(C*π*D 2 W /4)) 2 =(Q 0 /(0.02626*D 2 W )) 2 H W (ft.) 0.000000 EXTENDED DETENTION ORIFICE ELEV. PROVIDED E 2P =E 1 +Dw/(2*12)+2*Hw E 2P (ft.) 578.62 WATER QUALITY VOLUME PROVIDED WQ VP Use E-Q-V from PondPack at E 2P WQvp (cfs) 4,290 VERIFY IF ENOUGH WATER QUALITY IS PROVIDED OKAY DESIGN CHANNEL PROTECTION ORIFICE (See Section 8.2 Step 7.) CHANNEL PROTECTION VOLUME REQUIRED CP VR (cu. ft.) 2,630 PERMANENT POOL VOLUME PROVIDED VP pool (cu. ft.) 4,290 TOTAL CHANNEL PROTECTION VOLUME REQUIRED TCP VR =CP VR +VP pool TCP VR (cu. ft.) 6,920 ELEVATION PERMANENT POOL (orifice invert above permanent pool) see above E 1 (ft.) 578.62 EXTENDED DETENTION ELEV. PROVIDED (rounded,1) see above E 2P (ft.) 578.62 EXTENDED DETENTION C PV ELEVATION Use E-Q-V from PondPack at Volume CPv E 3 (ft.) 579.35 AVERAGE HEAD WATER QUALITY H 0 =(E 3 -E 1 )/2 H 0 (ft.) 0.37 AVERAGE HEAD CHANNEL PROTECTION H 1 =(E 3 -E 2P )/2 H 1 (ft.) 0.37 AVERAGE DISCHARGE (release rate in 24 hr) Q 0C =CP VR /(24hr*3600sec) Q 0C (cfs) 0.0304 AVERAGE DISCHARGE (calculated at WQ orifice ) Q W =0.02626*D 2 W *Hw 0.5 Q W (cfs) 0.00 DISCHARGE CHANNEL PROTECTION Q 1C =Q 0C -Q W Q 1C (cfs) 0.0304 ORIFICE DIAMETER CALCULATION D 1C =6.166*Q 0.5 0.25 1C /H 1 D 1C (in.) 1.384 ORIFICE DIAMETER ROUNDDOWN @ 1/8) D 1C (in.) 1 3/8 ORIFICE DIAMETER PROVIDED D CP (in.) 1 3/8 AVERAGE HEAD PROVIDED H W =(Q 1C /(C*π*D CP /4)) 2 =(Q 1C /(0.02626*D 2 CP )) 2 H CP (ft.) 0.38 EXTENDED DETENTION ELEV. PROVIDED E 2CP =E 2P +Dcp/(2*12)+2*Hcp E 2CP (ft.) 579.43 TOTAL CHANNEL PROTECTION VOLUME PROVIDED Use E-Q-V from PondPack at E 2CP CPvp (cu. ft.) 7,192 NET CHANNEL PROTECTION VOLUME PROVIDED CP V =CP VP -VPpool (cu. ft.) 2,902 VERIFY IF ENOUGH CHANNEL PROTECTION VOLUME IS PROVIDED OKAY

PROPRIETARY PRACTICE WORKSHEET Continuous Deflective Separation Unit JMC Project: 5043 Design Point: 1 Drainage Area: 1B Coefficients for the equation unit peak [R = I a / P] [C i = A x R 2 + B x R + C] Rainfall Distribution Type: III A B C C 0-1.774 0.3301 2.4577 C 1 1.8622-0.7397-0.4627 C 2-0.0648 0.2276-0.1932 Site Data for Drainage Area to be Treated by Practice DESCRIPTION Design Storm [90% Rainfall Event Number] Impervious Area Area Percent Impervious Runoff Volume [0.05 + 0.009 x %I] TOTAL VOLUME Required [WQ V = (P x R V x A) / 12] Pretreatment Required for Infiltration System is 50% WQ V SYMBOL VALUE UNITS P 1.3 In I 0.67 Ac A 0.86 Ac %I 78.10 % R V 0.75 WQ V 3,066 Pre WQ V 1,533 Water Quality Peak Flow Calculation DESCRIPTION Required Pretreatment Water Quality Volume Design Storm [90% Rainfall Event Number] or [1-yr Storm Depth] Time of Concentration Runoff Volume [Q = WQ V / (A x 3630)] Curve Number [CN = 1000 / (10 + 5P + 10Q - 10 x (Q 2 + 1.25 QP) ½ ] Curve Number Initial Abstraction [I a = 200 / CN - 2] Ratio [R = I a / P] C 0 = A x R 2 + B x R + C C 1 = A x R2 + B x R + C C 2 = A x R2 + B x R + C Unit Peak Discharge Peak Discharge [Q p = q u x A x Q / 640] SYMBOL VALUE UNITS WQ V 1,533 P 1.3 In t c 0.0833 Hr Q 0.49 In CN 89.11 CN 89 I a 0.24 In R 0.19 C 0 2.46 C 1-0.54 C 2-0.15 q u 720.45 cfs/mi 2 /in Q p 0.48 cfs Proposed Device DESCRIPTION Water Quality Peak Flow Provided Water Quality Volume Provided [WQ V = 640 x 3600 x Q P x P / q u ] Model Designation Quantity SYMBOL VALUE UNITS Q p 0.7 cfs WQ V 2,239 Contech CDS2015-4 1 Date Printed: 4/17/2012

Available Models Precast** Cast In Place Inline Offline Offline 1. Structure diameter represents the typical inside dimension of the concrete structure. Offline systems will require additional concrete diversion components. 2. Depth Below Pipe and Sump Capacities can vary to accommodate specific site design. 3. Water Quality Flow is based on 80% removal of a Particle Size Distribution (PSD) having a mean particle size: d50=125-µm, which is a typical PSD gradation characterizing particulate matter (TSS/SSC) in urban rainfall runoff. Water Quality Flow, Particle Size & Performance Notes: 80% removal (Re=80%) performance forecasts of the PSD having a d50=125-µm is derived from controlled tests of a unit equipped with 2400-µm screen. Performance forecasts for specific particle size gradations or d50s=50, 75, 125, 150 & 200-µm are also available. Removal forecasts based on unit evaluations conducted in accordance with the Technology Assessment Protocol - Ecology (TAPE) protocols, Washington Department of Ecology (WASDOE). Units can be sized to achieve specific Re performance for peak flow rates for specific Water Quality Flows, over the hydrograph of a Water Quality Storm Event or sized to meet a specific removal on an average basis using accepted probabilistic methods. When sizing based on a specific water quality flow rate, the required flow to be treated should be equal to or less than the listed water quality flow for the selected system. Contact our support staff for the most cost effective sizing for your area. page 6 Typical Internal MH Diameter or Typical Depth 2 Below Water Quality Flow 3 Screen Typical Equivalent ID 1 Pipe Invert 125 µm Diameter/Height Sump Capacity CDS Model ft m ft m cfs L/s ft m yd 3 m 3 CDS2015-4 4 1.2 3.5 1.1 0.7 19.8 2.0/1.5 0.6/0.5 0.5 0.4 CDS2015 5 1.5 5.2 1.6 0.7 19.8 2.0/1.5 0.6/0.5 1.3 1.0 CDS2020 5 1.5 5.7 1.7 1.1 31.2 2.0/2.0 0.6/0.6 1.3 1.0 CDS2025 5 1.5 6.0 1.8 1.6 45.3 2.0/2.5 0.6/0.8 1.3 1.0 CDS3020 6 1.8 6.2 1.9 2.0 56.6 3.0/2.0 0.9/0.6 2.1 1.6 CDS3030 6 1.8 7.1 2.2 3.0 85.0 3.0/3.0 0.9/0.9 2.1 1.6 CDS3035 6 1.8 7.6 2.3 3.8 106.2 3.0/3.5 0.9/1.1 2.1 1.6 CDS4030 8 2.4 8.6 2.6 4.5 127.4 4.0/3.0 1.2/0.9 5.6 4.3 CDS4040 8 2.4 9.7 3.0 6.0 169.9 4.0/4.0 1.2/1.2 5.6 4.3 CDS4045 8 2.4 10.3 3.1 7.5 212.4 4.0/4.5 1.2/1.4 5.6 4.3 CDS3020-D 6 1.8 6.2 1.9 2.0 56.6 3.0/2.0 0.9/0.6 2.1 1.6 CDS3030-DV 6 1.8 6.9 2.1 3.0 85.0 3.0/3.0 0.9/0.9 2.1 1.6 CDS3030-D 6 1.8 7.1 2.2 3.0 85.0 3.0/3.0 0.9/0.9 2.1 1.6 CDS3035-D 6 1.8 8.7 2.6 3.8 106.2 3.0/3.5 0.9/1.1 2.1 1.6 CDS4030-D 7 2.1 8.6 2.6 4.5 127.4 4.0/3.0 1.2/0.9 4.3 3.3 CDS4040-D 7 2.1 9.6 2.9 6.0 169.9 4.0/4.0 1.2/1.2 4.3 3.3 CDS4045-D 7 2.1 10.1 3.1 7.5 212.4 4.0/4.5 1.2/1.4 4.3 3.3 CDS5042-DV 9.5 2.9 9.6 2.9 9.0 254.9 5.0/4.2 1.5/1.3 1.9 1.5 CDS5640-D 8 2.4 9.5 2.9 9.0 254.9 5.6/4.0 1.7/1.2 5.6 4.3 CDS5050-DV 9.5 2.9 10.3 3.1 11 311.5 5.0/5.0 1.5/1.5 1.9 1.5 CDS5653-D 8 2.4 10.9 3.3 14 396.5 5.6/5.3 1.7/1.6 5.6 4.3 CDS5668-D 8 2.4 12.4 3.8 19 538.1 5.6/6.8 1.7/2.1 5.6 4.3 CDS5678-D 8 2.4 13.4 4.1 25 708.0 5.6/7.8 1.7/2.4 5.6 4.3 CDS7070-DV 12 3.7 14 4.3 26 736.3 7.0/7.0 2.1/2.1 3.3 2.5 CDS10060-DV 17.5 5.3 12 3.7 30 849.6 10.0/6.0 3.0/1.8 5.0 or 10.2 3.8 or 7.8 CDS10080-DV 17.5 5.3 14 4.3 50 1416.0 10.0/8.0 3.0/2.4 5.0 or 10.2 3.8 or 7.8 CDS100100-DV 17.5 5.3 16 4.9 64 1812.5 10.0/10.0 3.0/3.0 5.0 or 10.2 3.8 or 7.8 CDS150134-DC 22 6.7** 22 6.7** 148 4191.4 15.0/13.4 4.6/4.1 20.4 15.6 CDS200164-DC 26 7.9** 26 7.9** 270 7646.6 20.0/16.4 6.1/5.0 20.4 15.6 CDS240160-DC 32 9.8** 25 7.6** 300 8496.2 24.0/16.0 7.3/4.9 20.4 15.6 **Sump Capacities and Depth Below Pipe Invert can vary due to specific site design