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HomeMy WebLinkAboutStormwater Report - 815 CHESTNUT STREET 1/23/2006 May 8, 2007 Stephen E. Foster,VP/Poject Manager Dutton& Garfield, Inc. 43 Gigante Drive Hampstead,NH 03841 Re: Watts Industries North Andover,MA Dear Mr. Foster: As requested, Port Engineering has conducted a topographic survey of the enlarged detention basin adjacent to Flagship Drive and has has revised the grading of the proposed upper detention basin to avoid impacts to the recently discovered water service. Enclosed for your use are three sets of revised site plans and one set of hydrology calculations which have been revised to reflect the enlarged lower detention basin and the re-designed upper detention basin. Very truly yours, Port Engine Associates, Inc. David T. u ette,PE PORT ENGINEERING Civil Engineers& Land Surveyors One Harris Street Newburyport,MA 01950 (978)465-8594 i HYDROLOGIC STORM RUNOFF COMPUTATIONS WATTS INDUSTRIES—FLAGSHIP DRIVE,NO. ANDOVER 05/08/07 Per the Peak Stormwater Flow table on page 3 of the"Hydrologic Storm Runoff Computations and Storm Drainage System Design'' prepared by Port Engineering Associates, Inc. and dated July 14, 1994,the pre-construction peak stormwater flows to Flagship Drive were as follows: 100-Year Storm 10-Year Storm 2-Year Storm 9.7 cfs 5.4 cfs 2.3 cfs Based upon the newly enlarged Flagship Drive detention basin and construction of the proposed detention basin(see the enclosed"Grading and Drainage Plan" revised 04/20/07), post construction peak stormwater flows are anticipated to be as follows: 100-Year Storm 10-Year Storm 2-Year Storm 9.0 cfs 4.4 cfs 2.1 cfs PODT ENGINEEGING Civil Engineers& Land Surveyors One Harris Street Newburyport,MA 01950 (978)465-8594 P:iP17001DOCUMENTSIDutton-20070508.doc;10/12/00 Page 2 SC-P2 %,O"" C-pi 'NV 'NV LOW POND. HIGH POfQ SubCa Reaeh ort Llhk Drainage Diagram for2007HYDR03 Prepared by{enter your company name here} 4/12/2007 HydroCAD®6.00 s/n 000482 ©1986-2001 Applied Microcomputer Systems 2007HYDR 03 Type 11124-hr Rainfall=3.10" Prepared by{enter your company name here} Page 1 HydroCAD®6 00 s/n 000482 ©1986-2001 Applied Microcomputer Systems 411212007 Subcatchment SC-P2: (new node) Runoff = 3.00 cfs @ 12.09 hrs, Volume= 0.213 of Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt=0.01 hrs Type III 24-hr Rainfall=3.10" Area(ac) CN Description 0.350 70 Woods, Good, HSG C 0.260 74 >75% Grass cover, Good, HSG C 0.790 98 Paved parking & roofs 1.400 87 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, 2007HYDR03 Type 11124-hr Rainfall=3.10" Prepared by{enter your company name here} Page 1 HydroCAD®6 00 sin 000482 ©1986-2001 Applied Microcomputer Systems 411212007 Subcatchment SC-P2: (new node) Hydrograph Plot 3.00 cfs -Runoff 3 . --- 2 = = ----------- w 0 LL 1 - ----------- - 0 1 2 3 4 5 6 7 8 9 ' 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hours) 2007HYDR03 Type 11124-hr Rainfall=3.90" Prepared by(enter your company name here} Page 1 H droCADO 6.00 s/n 000482 ©1986-2001 Applied Microcomputer Systems 4/12/2007 Pond HIGH POND: PROPOSED UPPER BASIN Inflow = 3.00 cfs @ 12.09 hrs, Volume= 0.213 of Outflow = 0.21 cfs @ 13.71 hrs, Volume= 0.193 af, Atten= 93%, Lag= 97.1 min Primary - 0.21 efs @ 13.71 hrs, Volume= 0.193 of Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Peak Elev= 276.02' Storage=4,612 cf Plug-Flow detention time= 251.5 min calculated for 0.193 of(91% of inflow) Storage and wetted areas determined by Prismatic sections Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 272.00 0 0 0 274.00 1,230 1,230 1,230 276.00 2,080 3,310 4,540 278.00 4,650 6,730 11,270 Primary OutFlow (Free Discharge) 1-Culvert 2=Orifice/Grate L =Orifice/Grate 3=Orifice/Grate # Routing Invert Outlet Devices 1 Primary 270.00' 18.0" x 36.0' long Culvert RCP, groove end w/headwall, Ke=0.200 Outlet Invert= 269.64' S= 0.0100 '/' n= 0.011 Cc= 0.900 2 Device 1 272.00' 2.0"Vert.Orifice/Grate C= 0.600 3 Primary 276.00' 2.0"Vert.Orifice/Grate X 4.00 C= 0.600 4 Device 1 277:00'. 18.0" Horiz.Orifice/Grate Limited to weir flow C= 0.600 2007HYDR03 Type Ill 24-hr Rainfall=3.90" Prepared by{enter your company name here} Page 1 HydroCAD®6 00 s/n 000482 ©1986-2001 4plied Microcomputer Systems 4/12/2007 Pond HIGH POND: PROPOSED UPPER BASIN Hydrograph Plot --- 3.00 cfs Inflow Primary w o LL 1 ------------ 0.21 cfs Q 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hours) 2007HYDR03 Type 11124-hr Rainfall=3.10" Prepared by{enter your company name here} Page 1 HydroCAD®6 00 stn 000482 01986-2001 Applied Microcomputer Systems 4/12/2007 Subcatchment SC-P1: (new node) Runoff = 5.34 cfs @ 12.14 hrs, Volume= 0.435 of Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Type III 24-hr Rainfall=3.10" Area ac CN Description 0.020 70 Woods, Good, HSG C 1.010 74 >75% Grass cover, Good, HSG C 1.600 98 Paved parking &roofs 2.630 89 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, 2007HYDR03 Type 11124-hr Rainfall=3.10" Prepared by{enter your company name here} Page 1 HydroCAD®6.00 s/n 000482 ©1986-2001 Applied Microcomputer Systems 4/12/2007 Subcatchment SC-P1: (new node) Hydrograph Plot 5.34 cfs —Runoff 5 = ---------- ----- -- '-----;----;--------- ' w 0 2 - -- ----------- I----- 1 - - 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hours) 2007HYDR03 Type Ill 24-hr Rainfall=3.90" Prepared by{enter your company name here} Page 1 HydroCAD®6 00 s/n 000482 ©1986-2001 Applied Microcomputer Systems 4/12/2007 Pond LOW POND: LOWER BASIN Inflow = 5.51 cfs @ 12.14 hrs, Volume= 0.629 of Outflow = 2.06 cfs @ 12.49 hrs, Volume= 0.632 af, Atten=63%, Lag= 20.8 min Primary = 2.06 cfs @ 12.49 hrs, Volume= 0.632 of Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Starting Elev=264.30' Storage= 1,869 cf Peak Elev= 266.68' Storage= 6,629 cf (4,760 cf above starting storage) Flood Elev= 272.00' Storage= 24,729 cf (22,860 cf above starting storage) Plug-Flow detention time= 72.7 min calculated for 0.589 of(94% of inflow) Storage and wetted areas determined by Prismatic sections Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 263.00 1,175 0 0 264.00 1,480 1,328 1,328 266.00 2,127 3,607 4,935 268.00 2,854 4,981 9,916 270.00 3,675 6,529 16,445 272.00 4,609 8,284 24,729 Primary OutFlow (Free Discharge) '—Culvert 2=Culvert 3=Culvert # Routing Invert Outlet Devices 1 Primary 263.87' 7.0" x 13.0' long Culvert RCP, sq.cut end projecting, Ke= 0.500 Outlet Invert=263.87' S=0.0000'/' n= 0.011 Cc= 0.900 2 Primary 266.61' 8.0" x 10.0'long Culvert RCP, sq.cut end projecting, Ke= 0.500 Outlet Invert=266.51' S= 0.0100'1' n= 0.011 Cc= 0.900 3 Primary 269.11' 10.0" x 8.0' long Culvert RCP, sq.cut end projecting, Ke= 0.500 Outlet Invert= 268.95' S= 0.0200'P n= 0.011 Cc= 0.900 2007HYDR03 Type 11124-hr Rainfall=3.10" Prepared by{enter your company name here) Page 1 HydroCAD®6 00 s/n 000482 ©1986-2001 Applied Microcomputer Systems 4/12/2007 Pond LOW POND: LOWER BASIN Hydrograph Plot 6 ----- - - - ; s 5.51 cfs Inflow —Primary 5 - ---- ---- w 0 2.06 cfs 0 .. :. ..:.. .:.. 1 ... ....; . .; . .; 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hours) 2007HYDR®3 Type 11124-hr Rainfall=4.80° Page 1 Prepared by{enter your Company name here} 4/12/2007 H droCAM 6.00 s/n 000482 ©1986-2001 Applied Microcomputer Systems Subcatchment SC-P2: (new node) Runoff = 5.46 cfs @ 12.09 hrs, Volume= 0.394 of Runoff by SCS TR-20 method, UH=SCS,Time Span=0.00-24.00 hrs, dt=0.01 hrs Type III 24-hr Rainfall=4.80" Area ac CN Description 0.350 70 Woods, Good, HSG C 0.260 74 >75% Grass cover, Good, HSG C 0.790 98 Paved parking&roofs 1.400 87 Weighted Average Tc Length Slope Velocity Capacity Description min feet ft/ft ft/sec cfs 6.0 Direct Entry, 2007HYDR03 Type 11124-hr Rainfall=4.80" Prepared by{enter your company name here} Page 1 HydroCADO 6.00 s/n 000482 ©1986-2001 Applied Microcomputer Systems 4/12/2007 Subcatchment S0-P2: (new node) Hydrograph Plot 6 --- ---- ---- ----- ; 5.46 cfs --Runoff 5 --- 4 --- w 0 2 , 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hours) 2007HYDR03 Type 11124-hr Rainfall=4.80" Prepared by{enter your company name here} Page 1 HydroCADO 6.00 s/n 000482 ©1986-2001 Applied Microcomputer Systems 4/12/2007 Pond HIGH POND: PROPOSED UPPER BASIN Inflow = 5.46 cfs @ 12.09 hrs, Volume= 0.394 of Outflow = 0.77 cfs @ 12.61 hrs, Volume= 0.346 af, Atten= 86%, Lag= 31.2 min Primary = 0.77 cfs @ 12.61 hrs, Volume= 0.346 of Routing by Stor-Ind method,Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Peak Elev= 277.04' Storage= 8,041 cf Plug-Flow detention time= 202.0 min calculated for 0.346 of(88% of inflow) Storage and wetted areas determined by Prismatic sections Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 272.00 0 0 0 274.00 1,230 1,230 1,230 276.00 2,080 3,310 4,540 278.00 4,650 6,730 11,270 Primary OutFlow (Free Discharge) 1-Culvert 2=Orifice/Grate LOrif= ice/Grate 3=Orifice/Grate # Routing Invert Outlet Devices 1 Primary 270.00' 18.0" x 36.0' long Culvert RCP, groove end w/headwall, Ke= 0.200 Outlet Invert= 269.64' S=0.0100'P n= 0.011 Cc= 0.900 2 Device 1 272.00' 2.0"Vert.Orifice/Grate C=0.600 3 Primary 276.00' 2.0"Vert. Orifice/Grate X 4.00 C= 0.600 4 Device 1 277.00' 18.0" Horiz.Orifice/Grate Limited to weir flow C= 0.600 2007HYDRO3 Type !1124-hr Rainfall=4.80" Page 1 Prepared by (enter your company name here) 4/12/2007 H droCAD®6.00 s/n 000482 ©1986-2001 lied Microcom uter Systems Pond HIGH POND: PROPOSED UPPER BASIN Hydrograph Plot g -°------------------------ --- 5.46 cis inflow —Primary ----- ----- ----------- w 0 tL ---- 1 077 - -- - - -------------- -- -----_- ? cfs 1 • 1' 1' 1 1 1 1' 1 i 1 1 i 1 0 0 1 2 3 4 5 6 7 8 9 10 1(hours)13 14 15 16 17 18 Time 19 20 21 22 23 24 2007HYDR03 Type 11124-hr Rainfall=4.80" Prepared by{enter your company name here} Page 1 HydroCAD®6.00 sin 000482 ©1986-2001 Applied Microcomputer Systems 4/12/2007 Subcatchment SC-P1: (neon node) Runoff = 9.41 cfs @ 12.14 hrs, Volume= 0.783 of Runoff by SCS TR-20 method, UH=SCS,Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Type III 24-hr Rainfall=4.80" Area (ac) CN Description 0.020 70 Woods, Good, HSG C 1.010 74 >75% Grass cover, Good, HSG C 1.600 98 Paved parking &roofs 2.630 89 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, 2007HYDR03 Type 11124-hr Rainfall=4.80" Prepared by{enter your company name here) Page 1 HydroCAD®6 00 s/n 000482 ©1986-2001 Applied Microcomputer Systems 4/12/2007 Subcatchment SC-P1: (new node) Hydrograph Plot 10 ----- --- ---- ---- - 9.41 cfs i Runoff 9 - - 8 ------------------------ 3 5 - --- ---- ---------------------- ---- ----- - 0 LL 3 - 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hours) 2007HYDR03 Type ///24-hr Rainfall=4.80" Prepared by{enter your company name here} Page 1 HydroCADD 6.00 s/n 000482 ©1986-2001 Applied Microcomputer Systems 4/12/2007 Pond LOW POND: LOUVER BASIN Inflow = 9.84 cfs @ 12.14 hrs, Volume= 1.130 of Outflow = 4.45 cfs @ 12.42 hrs, Volume= 1.130 af, Atten= 55%, Lag= 17.1 min Primary = 4.45 cfs @ 12.42 hrs, Volume= 1.130 of Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Starting Elev= 264.30' Storage= 1,869 cf Peak Elev=268.18' Storage= 10,501 cf (8,632 cf above starting storage) Flood Elev=272.00' Storage=24,729 cf (22,860 cf above starting storage) Plug-Flow detention time= 57.9 min calculated for 1.087 of(96% of inflow) Storage and wetted areas determined by Prismatic sections Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 263.00 1,175 0 0 264.00 1,480 1,328 1,328 266.00 2,127 3,607 4,935 268.00 2,854 4,981 9,916 270.00 3,675 6,529 16,445 272.00 4,609 8,284 24,729 Primary OutFlow (Free Discharge) 1=Culvert 2=Culvert 3=Culvert # Routing Invert Outlet Devices 1 Primary 263.87' 7.0" x 13.0' long Culvert RCP, sq.cut end projecting, Ke= 0.500 Outlet Invert=263.87' S= 0.0000 '/' n= 0.011 Cc= 0.900 2 Primary 266.61' 8.0" x 10.0'long Culvert RCP, sq.cut end projecting, Ke= 0.500 Outlet Invert=266.51' S= 0.0100 '1' n= 0.011 Cc= 0.900 3 Primary 269.11' 1.0.0" x 8.0' long Culvert RCP, sq.cut end projecting, Ke= 0.500 Outlet Invert=268.95' S= 0.0200 '/' n= 0.011 Cc= 0.900 2007HYDR03 Type 11124-hr Rainfall=4.80" Page 1 Prepared by{enter your company name here) 4/12/2007 H droCADO 6.00 s/n 000482 ©1986-2001 Applied Microcomputer Sy stems Pond LOW POND: LOWER BASIN Hydrograph Plot 11 ; —inflow ' -- ---- — ` ' 9.84 cis 10 ? Primary ---- ---- ---- -- 8 ---- -------- .— ----- --------- ----, 0 5 4.45 cfs a ; 2 ----- 0 0 1 2 3 4 5 6 7 8 9 10 14 15 16 17 18 19 20 21 22 23 24 Time (hours) 2007HYDR03 Type Ill 24-hr Rainfall=7.00" Prepared by{enter your company name here} Page 1 HydroCAD®6 00 s/n 000482 ©1986-2001 /Applied Microcomputer Systems 4/12/2007 Subcatchment SC-P2: (new node) Runoff = 8.65 cfs @ 12.08 hrs, Volume= 0.639 of Runoff by SCS TR-20 method, UH=SCS,Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Type III 24-hr Rainfall=7.00" Area (ac) CN Description 0.350 70 Woods, Good, HSG C 0.260 74 >75% Grass cover, Good, HSG C 0.790 98 Paved parking & roofs 1.400 87 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, 2007HYDR03 Type III 24-hr Rainfall=7.00" Prepared by{enter your company name here} Page 1 HydroCAD®6 00 s/n 000482 ©1986-2001 Applied Microcomputer Systems 4/12/2007 Subcatchrnent SC-P2: (nevi node) Hydrograph Plot 9 ----------I------t =-----= -'8.65 ---s Runoff 6 -- ----- ----------------------- --- ---- ---- ---- ---- 0 U- 4 ----------------------I------I ---- -- - ---- ---- --- ---- 3 : - ---- --- ---- ---- ----- 2 I----- -- ----- 0 ° R °. ..;. . ,. 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hours) 2007HYDR03 Type Ill 24-hr Rainfall=7.00" Prepared by{enter your company name here} Page 1 H droCPbO 6.00 s/n 000482 ©1986-2001 Applied Microcom uter Systems 4112/2007 Pond HIGH POND: PROPOSED UPPER BASIN Inflow = 8.65 cfs @ 12.08 hrs, Volume= 0.639 of Outflow = 5.57 cfs @ 12.18 hrs, Volume= 0.569 af, Atten= 36 Lag= 5.6 min Primary = 5.57 cfs @ 12.18 hrs, Volume= 0.569 of Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Peak Elev= 277.46' Storage=9,458 cf Plug-Flow detention time= 145.4 min calculated for 0.569 of(89% of inflow) Storage and wetted areas determined by Prismatic sections Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 272.00 0 0 0 274.00 1,230 1,230 1,230 276.00 2,080 3,310 4,540 278.00 4,650 6,730 11,270 Primary OutFlow (Free Discharge) T-1=Culvert '[: 2=Orifice/G L =Orifice/Grate 3=Orifice/Grate # Routing Invert Outlet Devices 1 Primary 270.00' 18.0" x 36.0' long Culvert RCP, groove end w/headwall, Ke=0.200 Outlet Invert= 269.64' S= 0.0100'P n= 0.011 Cc-- 0.900 2 Device 1 272.00' 2.0"Vert.Orifice/Grate C=0.600 3 Primary 276.00' 2.0"Vert. Orifice/Grate X 4.00 C= 0.600 4 Device 1 277.00' 18.0" Horiz. Orifice/Grate Limited to weir flow C= 0.600 2007HYDR03 Type 11124-hr Rainfall=7.00" Prepared by{enter your company name here} Page I HydroCAM 6.00 s/n 000482 ©1986-2001 Applied Microcomputer Systems 4112/2007 Pond HIGH POND: PROPOSED UPPER BASIN Hydrograph Plot Inflow —-- I 865 --- ----------------------------------- 9 ---------------- ---------------- ---------- ---------- 8' ----------- ----- ---------- ----- ----- ------ - ---------------------- 7 ---------------------------------------------------- ------ . . . . . 5. --- ----- ----- 6 ------: ----------------- ---------- 5 ---- I------ ----- --- ---------- ---------------------- LL ----- ---------- 4- ------------------ ---------- ----- --- 3- ------------------------------------ ---------- ----------- ----- ---------- ------I 0 7 8 9 1 1 0 11 12 13 14 1,5 16 1 1 7 18 19 20 21 22 23 24 Time (hours) 2007HYDR03 Type 11124-hr Rainfall=7.00° Prepared by{enter your company name here} Page 1 HydroCAD®6 00 s/n 000482 01986-2001 Applied Microcomputer Systems 4/12/2007 Subcatchment SC-P1: (new node) Runoff = 14.66 cfs @ 12.14 hrs, Volume= 1.249 of Runoff by SCS TR-20 method, UH=SCS,Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Type III 24-hr Rainfall=7.00" Area(ac) CN Description 0.020 70 Woods, Good, HSG C 1.010 74 >75% Grass cover, Good, HSG C 1.600 98 Paved parking & roofs 2.630 89 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, 2007HYDR03 Type 111 24-hr Rainfall=7.00" Prepared by{enter your company name here} Page 1 HydroCAD®6.00 sin 000482 ©1986-2001 Applied Microcomputer Systems 4/12/2007 Subcatchment SC-P1: (new node) Hydrograph Plot 16 , 15 — ---- ----- 14.66 cfs -- - - - ----- ---- —Runoff 14 --------------- - ------ 13 , --- ---- --- ---- ---- ---- --- --- ---- --- ---- --- 12 --- ----- --- ----- ----------- 10 = ------= --------------- h 9 - ---- ------------ 8 ;, 0 IC 7 - ---- ---- --- ---- 3-- ------------------------------ ------------ ----I------ --- ----- 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hours) 2007HYDR03 Type 11124-hr Rainfall=7.00" Prepared by{enter your company name here} Page 1 HydroCAD®6.00 s/n 000482 ©1986-2001 Applied Microcomputer Systems 4/12/2007 Pond LOW POND: LOWER BASIN [79] Warning: Submerged Pond HIGH POND Primary device# 1 INLET by 0.53' Inflow = 19.80 cfs @ 12.15 hrs, Volume= 1.819 of Outflow = 9.05 cfs @ 12.42 hrs, Volume= 1.816 af, ,ktten= 54%, Lag= 16.0 min Primary = 9.05 cfs @ 12.42 hrs, Volume= 1.816 of Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs, Starting Elev= 264.30' Storage= 1,869 cf Peak Elev= 270.53' Storage= 18,624 cf (16,755 cf above starting storage) Flood Elev=272.00' Storage=24,729 cf (22,860 cf above starting storage) Plug-Flow detention time=50.0 min calculated for 1.773 of(97% of inflow) Storage and wetted areas determined by Prismatic sections Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 263.00 1,175 0 0 264.00 1,480 1,328 1,328 266.00 2,127 3,607 4,935 268.00 2,854 4,981 9,916 270.00 3,675 6,529 16,445 272.00 4,609 8,284 24,729 Primary OutFlow (Free Discharge) r1=Culvert 2=Culvert 3 Culvert # Routing Invert Outlet Devices 1 Primary 263.87' 7.0" x 13.0' long Culvert RCP, sq.cut end projecting, Ke=0.500 Outlet Invert=263.87' S= 0.0000'/' n= 0.011_ Cc= 0.900 2 Primary 266.61' 8.0" x 10.0' long Culvert RCP, sq.cut end projecting, Ke= 0.500 Outlet Invert=266.51' S= 0.0100'P n= 0.011 Cc= 0.900 3 Primary 269.11' 10.0" x 8.0' long Culvert RCP, sq.cut end projecting, Ke=0.500 Outlet Invert=268.95' S= 0.02007' n= 0.011 Cc= 0.900 2007HYDR03 Type 111 24-hr Rainfall=7.00" Prepared by{enter your company name here} Page 1 HydroCAD®6.00 s/n 000482 ©1986-2001 Applied Microcomputer Systems 4/12/2007 Pond LOW POND: LOWER BASIN y ogra H dr h Plot p 22 - 21 -----------------------20-- -; ;---- ----;--- ;--- ---- ---- 19.80 - - ----- --- - ----------- - 19 --------------- - - .80 cfs 19 Inflow Primary 18 -- 17 - ---- --- ----- ---- 16 - 15 t 14 ; 13 ------------------ .. 12 : 3 11 = =----------- ----- - - 0 10 ---------- A a05 cfs = LL ; ----- ----- 9 ; ? i i 8 ; _; ! ? i 7 i i i i i i -- --- 6 5 4 ; ---- -- - -- 3 --------- -- --- --- ---- 2- - ----=----,---- = _ - - ;----=---- ---- -- -------- - , 0 ..,.:....,. ;...., .. ; 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hours)