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Stormwater Drainage Report 2-25-09
I I I I I I I I I I I I I I I I I I I STORMWATER DRAINAGE REPORT CITY OF CHANHASSEN RECE!VED FEB 2 6 2009 CHANHASSEN PLANNlNG DF-PT Subdivision Project (Plowe #08-1227) Chanhassen, MN ORIGINAL DATE: January 15, 2009 Rev #1: January 28, 2009 Rev #2: February 25, 2009 PLOWE ENGINEERING, INC. 6776 Lake Drive, Suite 110 Lino Lakes, Minnesota 55014 Office (651) 361-8210 Fax (651) 361-8701 I I I I I I I I I I I I I I I I I I I SUMMARY OF RESULTS GENERAL This 7 . I-acre parcel will be subdivided into 7 single-family lots. Approximately two-thirds of the existing site drains directly to Lake Susan; the remaining portion drains to a small wetland on the east side of the property. Proposed drainage from the street and most of the roof and driveways will be collected and routed toa new NURP stormwater pond to be constructed on Lot 1 Block 2. This pond, in turn, drains to the small wetland. The remainder of the site will follow existing drainage patters and directly to Lake Susan. For the wetland, it is assumed that the culverts between the wetland and the driveways actas equalizers, and thatthese areas would "botlllce"at thesame rate. It is also assumed that these areas act as a trapped basin, with no clearly defined outlet. It would appear from the contour information from the County that these areas would overflow south rather than north; namely, over the trail and to the existing catch basins in Waters Edge Drive. WATER QUALITY Water quality is provided via the use of aNURP pond, which collects most ofthe proposed hard surface (new street, roof and driveways). An analysis for dead storage (volume below NWL) for the 2.5-inch storm event follows: Area to Pond Average CN Runoff (2.5" event) = 124,121 sf = 74 = 0.61 in Required Dead Storage: Provided Dead Storage: 6,309 cf 9,348 sf [124,121 sf x 0.61 in x (1/12)] [From HydroCAD report] WATER QUANTITY A 6-inch orifice is used in the pond's outlet structure to contol all storm events. A comparison of existipg versus proposed rates is provided. An analysis of the 10" storm eventis inclUded to demonstrate capacity for the pond's overflow swale. I I I I I I I I I I I I I I I I I I I RATE COMPARISON TO LAKE SUSAN Rate Control STORM EVENT (Rate Control) 2-yr . 1 O-yr 100-yr 10-day Snomelt (cfs) (cfs) (cfs) lcfs) Existing (1) 2.33 8.32 18.25 3.19 Proposed (1) 2.36 7.93 16.97 2.85 TO WETLAND Rate Control STORM EVENT (Rate Control) 2-yr 10-yr 100-yr 10-day Snomelt (cfs) (cfs) (cfs) (cfs) Existing (2) 2.67 8.95 19.14 3.13 Proposed (Pond P + 2) 3.09 9.28 19.59 2.69 WETLAND HWL STORM EVENT HWL Comparison 10-day 100-yr 100-yr Snowmelt Back- to-Back . Existing 904.59 906.63 907.01 Proposed 904.96 906.84 907.11 I I I I I I I I I I I I I I I I I I I To Lake To Wetland ~Ub~ IReachl ~ ~ ~ Exist Wetland Drainage Diagram for 081227 Existing Prepared by Plowe Engineering, Inc., Printed 2/25/2009 HydroCAO@ 8.50 sIn 001574 @ 2007 HydroCAD Software Solutions LLC I 081227 Existing Prepared by Plowe Engineering, Inc. HvdroCAOO 8.50 sin 001574 @2oo7 HvdroCAD Software Solutions LLC Type II 24-hr 2-year (2.80') Rainfall=2.80" Printed 2/25/2009 Page 4 I Time span=0.00-200.00 hrs, dt=0.01 hrs, 20001 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method I Subcatchment 1: To Lake Runoff Area=295, 176 sl 9.26% Impervious Runoff Depth=0.42" Flow Length=625' Tc=18.3 min CN=65 Runoff=2.33 cIs 10,275 cl Subcatchment2: To Wetland Runoff Area=289,267 sl 10.84% Impervious Runoff Depth=0.45" Flow Length=300' Slope=0.0520 'f Tc=17.5 min CN=66 Runoff=2,67 cIs 10,908 cl I Pond ExW: Exist Wetland Peak Elev=902.55' Slorage=10,908 cl Inflow=2.67 cIs 10,908 cl Outflow=O.OO cIs 0 cf I Total Runoff Area = 584,443 sf Runoff Volume = 21,183 cf Average Runoff Depth = 0.43" 89.96% Pervious = 525,771 sf 10.04% Impervious = 58,672 sf I 1 I I 1 1 1 'I I I I I I I I 081227 Existing Prepared by Plowe Engineering, Inc. HvdroCAOO 8.50 sin 001574 @ 2007 HVdroCAD Software Solutions .lLC Type 1/ 24-hr 2-year (2. 80'? Rainfa//=2.80" Printed 2/25/2009 Pl'loe 5 I I Runoff Summary for Subcatchment 1: To Lake 2.33 cfs @ 12.14 hrs, Volume= 10,275 ef, Depth= 0.42" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs Type II 24-hr 2-year (2.80") Rainfall=2.80" I I Area (sf) 13,695 13,630 8,830 259,021 295,176 267,851 27,325 CN Description 98 Roof 98 Bituminous/Concrete Drive 85 Gravel Drive 61 >75% Grass cover, Good, HSG B 65 Weighted Average Pervious Area Impervious Area I Tc Length Slope Velocity Capacity Description (min) (feet) (ftlft) (ftlsec) (efs) 16.9 300 0.0567 0.30 Sheet Flow, Grass: Short n= 0.150 P2= 2.70" 1.4 325 0.0635 3.78 Shallow Concentrated Flow, Grassed Waterway Kv= 15.0 fps 18.3 625 Total I I Runoff Summary for Subcatchment 2: To Wetland 2.67 cfs @ 12.13 hrs, Volume= 10,908 ef, Depth= 0.45" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs Type II 24-hr 2-year (2.80") Rainfall=2.80" I I I Area (sf) 11,707 4,500 6,500 8,150 8,640 8,872 240,898 289,267 257,920 31,347 CN Description 98 Existing Roof 98 Existing Cone. Drive 98 Existing Bit. Drive 85 Existing Gravel Drive 98 Existing Bit. Trail 85 Wetland 61 >75% Grass cover, Good, HSG B 66 Weighted Average Pervious Area Impervious Area T c Length Slope Velocity Capacity Description (min) (feet) (ftlft) (ftlsec) (cfs) 17..5 300 0.0520 0.29 Sheet Flow, Grass: Short n= 0.150 P2= 2.70" I I Inflow Area = Inflow Outflow Primary Summary for Pond ExW: Exist Wetland 289,267 sf, 10.84% Impervious, 2.67 cfs @ 12.13 hrs, Volume= 0.00 cfs @ 0.00 hrs, Volume= 0.00 cfs @ 0.00 hrs, Volume= Inflow Depth = 0.45" for 2-year (2.80") event 10,908 cf o cf, Allen= 100%, Lag= 0.0 min o cf I Routing by Dyn-Stor-Ind method, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs Peak Elev= 902.55' @ 25.02 hrs Surf.Area= 11,390 sf Storage= 10,908 cf Plug-Flow detention time= (not calculated: initial storage excedes outflow) Center-of-Mass del. time= (not calculated: no outflow) I I I I Volume #1 Elevation (feet) 899.40 902.00 904.00 910.00 Device #1 Routing Device 2 Invert 899.40' Avail.Storage Storage Description 425,394 cf Custom Stage Data (Prismatic) Listed below (Recalc) #2 Primary Surf. Area (Sq-ft) o 4,954 28,500 100,000 Inc.Store (cubic-feet) o 6,440 33,454 385,500 Cum. Store (cubic-feet) o 6,440 39,894 425,394 Invert Outlet Devices 907.00' 10.0' long x 8.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.43 2.54 2.70 2.69 2.68 2.68 2.66 2.64 2.64 2.64 2.65 2.65 2.66 2.66 2.68 2.70 2.74 906.49' 2.00' x 3.00' Horiz. Orifice/Grate Limited to weir flow C= 0.600 Primary OutFlow Max=O.OO cfs @ 0.00 hrs HW=899.40' (Free Discharge) L2=Orifice/Grate (Controls 0.00 cfs) L1=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) I I 081227 Existing Prepared by Plowe Engineering, Inc. HydroCAOO 8.50 sin 001574 @2007 HydroCAD Software Solutions LLC Spillway 1-day 10-day 10-day Snowmelt Rainfall=7.20", AMC=4 Printed 2/25/2009 Page 6 I Time span=0.00-200.00 hrs, dt=0.01 hrs, 20001 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method I Subcatchment 1: To Lake Runoff Area=295, 176 sf 9.26% Impervious Runoff Depth>6.47" Flow Length=625' Te=18.3 min Adjusted CN=98 Runoff=3.19 efs 159,236 ef Subeatchment2: To Wetland Runoff Area=289,267 sf 10.84% Impervious Runoff Depth>6.47" Flow Lenglh=300' Slope=0.0520 'f Te=17.5 min Adjusted CN=98 Runoff=3.13 efs156,053 ef I Pond ExW: Exist Wetland Peak Ele\(=906.63' Storage=.156,052 ef Infiow=3.13 efs 156,053 cf OutfJow=O.OO efs 0 ef I Total Runoff Area = 584,443 sf Runoff Volume = 315,290 cf Average Runoff Depth = 6.47" 89.96% Pervious = 525,771 sf 10.04% Impervious = 58,672 sf I I I I I I I I I I I I I I I I 081227 Existing Prepared by Plowe Engineering, Inc. HvdroCAOO 8.50 sin 001574 @2007 HvdroCAD Software Solutions LLC Spillway 1-day 10-day 10-day Snowmelt Rainfal/=7.20", AMC=4 Printed 2/25/2009 Page 7 I Runoff Summary for Subcatchment 1: To Lake 3.19 cls@ 121.49 hrs, Volume= 159,236 cI, Depth> 6.47" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs Spillway 1-day 10-day 10-day Snowmelt Rainfall=7.20", AMC=4 I I Area (sf) 13,695 13,630 8,830 259,021 295,176 267,851 27,325 CN Description 98 Roof 98 Bituminous/Concrete Drive 85 Gravel Drive 61 >75% Grass cover, Good, HSG B 65 Weighted Average, Adjusted for AMC to CN = 98 Pervious Area Impervious Area I Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 16.9 300 0.0567 0.30 Sheet Flow, Grass: Short n= 0.150 P2= 2.70" 1.4 325 0.0635 3.78 Shallow Concentrated Flow, Grassed Waterway Kv= 15.0 fps 18.3 625 Total I I Runoff Summary for Subcatchment 2: To Wetland 3.13 cfs@ 121.47 hrs, Volume= 156,053 cf, Depth> 6.47" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs Spillway 1-day 10-day 10-day Snowmelt Rainfall=7.20", AMC=4 I I I Area (sf) 11,707 4,500 6,500 8,150 8,640 8,872 240,898 289,267 257,920 31,347 CN Description 98 Existing Roof 98 Existing Cone. Drive 98 Existing Bit. Drive 85 Existing Gravel Drive 98 Existing Bit. Trail 85 Wetland 61 >75% Grass cover, Good, HSG B 66 Weighted Average, Adjusted for AMC to CN = 98 Pervious Area Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 17.5 300 0.0520 0.29 Sheet Flow, Grass: Short n= 0.150 P2= 2.70" I I Inflow Area = Inflow Outflow Primary Summary for Pond ExW: Exist Wetland 289,267 sf, 10.84% Impervious, 3.13 cfs @ 121.47 hrs, Volume= 0.00 cis @ 0.00 hrs, Volume= 0.00 cis @ 0.00 hrs, Volume= Inflow Depth> 6.47" for 10-day Snowmelt event 156,053 cf o cf, Allen= 100%, Lag= 0.0 min o cf I Routing by Dyn-Stor-Ind method, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs Peak Elev= 906.63' @ 200.00 hrs Surf.Area= 59,839 sf Storage= 156,052 cf Plug-Flow detention time= (not calculated: initial storage excedes outflow) Center-of-Mass det. time= (not calculated: no outflow) I I I I Volume #1 Elevation (feet) 899.40 902.00 904.00 910.00 Device #1 RoutinQ Device 2 Invert 899.40' Avail.StoraQe StoraQe Description 425,394 cf Custom Stage Data (Prismatic) Listed below (Recalc) #2 Primary Surf.Area (sQ-ft) o 4,954 28,500 100,000 Cum.Store (cubic-feet) o 6,440 39,894 425,394 Inc. Store (cubic-feet) o 6,440 33,454 385,500 Invert Outlet Devices 907.00' 10.0' long x 8.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coet. (English) 2.43 2.54 2.70 2.69 2.68 2.68 2.66 2.64 2.64 2.64 2.65 2.65 2.66 2.66 2.68 2.70 2.74 906.49' 2.00' x 3.00' Horiz. Orifice/Grate Limited to weir flow C= 0.600 Primary OutFlow Max=O.OO cis @ 0.00 hrs HW=899.40' (Free Discharge) L2=Orifice/Grate (Controls 0.00 cfs) L1=Broad-Crested Rectangular Weir ( Controls 0.00 cts) I I I 081227 Existing Prepared by Plowe Engineering, Inc. HydroCAOO8.50 sin 001574 @2007 HydroCAD Software Solutions LLC Type /I 24-hr 10-year (4.20'? Rainfal/=4.20" Printed 2/25/2009 Page 8 Time span=0.00-200.00 hrs, dt=0.01 hrs, 20001 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method I Subcatchment1: To Lake. Runoff Area=295,176 sf 9.26% Impervious Runoff Depth=1.15" Flow Length=625' Tc=16.3 min CN=65 Runoff=6.32 cfs 26,200 cf Subcatchment2: To Wetland Runoff Area=289,267sf 10.84% Impervious Runoff Depth=1.21" Flow Length=300' Slope=0.0520 'f Tc=17.5 min CN=66 Runoff=8.95 cfs 29,105 cf I Pond ExW: Exist Wetland Peak Elev=903.59' 810rage.=29,105 cf Inflow=8.95 cfs 29,1050f Outflow=O.OO cfs 0 cf I Total Runoff Area = 584,443 sf Runoff Volume = 57,305 cf Average Runoff Depth = 1.18" 89.96% Pervious = 525,771 sf 10.04% Impervious = 58,672 sf I I I I I I I I I I I I I I I I 081227 Existing Prepared by Plowe Engineering, Inc. HvdroCAD@8:50 sin 001574 @2oo7 HvdroCAD Software Solutions LLC Type /I 24-hr 10-year (4.20'; Rainfal/=4.20" Printed 2/25/2009 Page 9 I Runoff Summary for Subcatchment 1: To Lake 8.32 cfs @ 12.12 hrs, Volume= 28,200 cf, Depth= 1.15" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs Type II 24-hr 1 O-year (4.20") Rainfall=4.20" I I Area (sf) 13,695 13,630 8,830 259,021 295,176 267,851 27,325 CN Description 98 Roof 98 Bituminous/Concrete Drive 85 Gravel Drive 61 >75% Grass cover, Good, HSG B 65 Weighted Average Pervious Area Impervious Area I Tc Length Slope Velocity Capacity Description (min) (feet) (fUfl) (fUsee) (cfs) 16.9 300 0.0567 0.30 Sheet Flow, Grass: Short n= 0.150 P2= 2.70" 1.4 325 0.0635 3.78 Shallow Concentrated Flow, Grassed Waterway Kv= 15.0 fps 18.3 625 Total I I Runoff Summary for Subcatchment 2: To Wetland 8.95 cfs @ 12.11 hrs, Volume= 29,105cf, Depth= 1.21" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs Type II 24-hr 10-year (4.20") Rainfall=4.20" I I I Area (sf) 11,707 4,500 6,500 8,150 8,640 8,872 240,898 289,267 257,920 31,347 CN Description 98 Existing Roof 98 Existing Cone. Drive 98 Existing Bit. Drive 85 Existing Gravel Drive 98 Existing Bit. Trail 85 Wetland 61 >75% Grass cover, Good, HSG B 66 Weighted Average Pervious Area Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (fUfl) (fUsee) (cfs) 17.5 300 0.0520 0.29 Sheet Flow, Grass: Short n= 0.150 P2= 2.70" I I Inflow Area = Inflow Outflow Primary Summary for Pond ExW: Exist Wetland 289,267 sf, 10.84% Impervious, 8.95 cfs @ 12.11 hrs, Volume= 0.00 cfs @ 0.00 hrs, Volume= 0.00 cfs @ 0.00 hrs, Volume= Inflow Depth = 1.21" for 10-year (4.20") event 29,105 cf o cf, Allen= 100%, Lag= 0.0 min o cf I Routing by Dyn-Stor-Ind method, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs Peak Elev= 903.59' @ 25.02 hrs Surf.Area= 23,626 sf Storage= 29,105 cf Plug-Flow detention time= (not calculated: initial storage excedes outflow) Center-of-Mass det. time= (not calculated: no outflow) I I I I Volume #1 Elevation (feet) 899.40 902.00 904.00 910.00 Device #1 RoutinQ Device 2 Invert 899.40' Avail.StoraQe StoraQe Description 425,394 cf Custom Stage Data (Prismatic) Listed below (Recalc) #2 Primary Surf.Area (sQ-fl) o 4,954 28,500 100,000 Inc. Store (cubic-feet) o 6,440 33,454 385,500 Cum.Store (cubic-feet) o 6,440 39,894 425,394 Invert 907.00' Outlet Devices 10.0' long x 8.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coet. (English) 2.43 2.54 2.70 2.69 2.68 2.68 2.66 2.64 2.64 2.64 2.65 2.65 2.66 2.66 2.68 2.70 2.74 2.00' x 3.00' Horiz. Orifice/Grate Limited to weir flow C= 0.600 906.49' Primary OutFlow Max=O.OO cfs @ 0.00 hrs HW=899.40' (Free Discharge) 't..-t.Orifice/Grate (Controls 0.00 cfs) 1=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) I I I 081227 Existing Prepared by Plowe Engineering, Inc. HydroCA()@8.50 sin 001574 @2007 HydroCAD Software Solutions LLC Type II 24-hr 1 DO-year (6. DO'? Rainfa/J=6.00" Printed 2/25/2009 Page 1 0 I Subcatchment 1: To Lake Subcatchment 2: To Wetland I Pond ExW: Exist Wetland I I I I I I I I I I I I I I I Time span=0.00-200.00 hrs, dt=0.01 hrs, 20001 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method Runoff Area=295, 176 sf 9.26% Impervious Runoff Depth=2.35" Flow Lenglh=625' Tc=18.3 min CN=65 Runoff=18.25 cfs 57,838 cf Runoff Area=289,267.sf. 10.84% Impervious Runoff Depth=2.44" Flow Length=300' Slope=O.0520 'f Tc=17.5 min CN=66 Runoff=19.14 cfs 58,823 cf Peak Elev=904.59' Slorage=58,823 cf Inflow=19.14 cfs 58,823 cf Outflow=O.OO cfs 0 cf Total Runoff Area = 584,443 sf Runoff Volume = 116,660 cf Average Runoff Depth = 2.40" 89.96% Pervious = 525,771 sf 10.04% Impervious = 58,672 sf I I 081227 Existing Prepared by Plowe Engineering, Inc. HvdroCAOO 8.50 sin 001574@ 2007 HvdroCAD Software Solutions LLC Type 1/24-hr 100-year (6.00" Rainfal/=6.00" Printed 2/25/2009 PagA 11 I Runoff Summary for Subcatchment 1: To Lake 18.25 cfs @ 12.12 hrs, Volume= 57,838 cf, Depth= 2.35" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs Type II 24-hr 100-year (6.00") Rainfall=6.00" . I I Area (sf) 13,695 13,630 8,830 259.021 295,176 267,851 27,325 CN Description 98 Roof 98 Bituminous/Concrete Drive 85 Gravel Drive 61 >75% Grass cover, Good. HSG B 65 Weighted Average Pervious Area Impervious Area I Tc Length Slope Velocity Capacity Description (min) (feet) (fUft) (fUsee) (cfs) 16.9 300 0.0567 0.30 Sheet Flow, Grass: Short n= 0.150 P2= 2.70" 1.4 325 0.0635 3.78 Shallow Concentrated Flow, Grassed Waterway Kv= 15.0 fps 18.3 625 Total I I Runoff Summary for Subcatchment 2: To Wetland 19.14 cfs @ 12.11 hrs, Volume= 58,823 cf, Depth= 2.44" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs Type II 24-hr 100-year (6.00") Rainfall=6.00" I I I Area (sf) 11,707 4,500 6,500 8,150 8,640 8,872 240,898 289,267 257,920 31,347 CN Description 98 Existing Roof 98 Existing Cone. Drive 98 Existing Bil. Drive 85 Existing Gravel Drive 98 Existing Bil. Trail 85 Wetland 61 >75% Grass cover, Good, HSG B 66 Weighted Average Pervious Area Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (fUft) (fUsee) (cts) 17.5 300 0.0520 0.29 Sheet Flow, Grass: Short n= 0.150 P2= 2.70" I I Inflow Area = Inflow Outflow Primary Summary for Pond ExW: Exist Wetland 289,267 st, 10.84% Impervious, 19.14 cts @ 12.11 hrs, Volume= 0.00 cts @ 0.00 hrs, Volume= 0.00 cts @ 0.00 hrs, Volume= Inflow Depth = 2.44" tor 100-year (6.00") event 58,823 cf o cf, Allen= 100%, Lag= 0.0 min Oct I Routing by Dyn-Stor-Ind method, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs Peak Elev= 904.59' @ 25.02 hrs Surf.Area= 35,544 st Storage= 58,823 ct Plug-Flow detention time= (not calculated: initial storage excedes outflow) Center-ot-Mass del. time= (not calculated: no outflow) I I I I Volume #1 Elevation (teet) 899.40 902.00 904.00 910.00 Device #1 RoutinQ Device 2 Invert 899.40' Avail.StoraQe StoraQe Description 425,394 cf Custom Stage Data (Prismatic) Listed below (Recalc) #2 Primary Surf.Area (Sq-ft) o 4,954 28,500 100,000 Inc. Store ( cubic-teet) o 6,440 33,454 385,500 Cum. Store (cubic-teet) o 6,440 39,894 425,394 Invert Outlet Devices 907.00' 10.0' long x 8.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coet. (English) 2.43 2.54 2.70 2.69 2.68 2.68 2.66 2.64 2.64 2.64 2.65 2.65 2.66 2.66 2.68 2.70 2.74 906.49' 2.00' x 3.00' Horiz. Orifice/Grate Limited to weir flow C= 0.600 Primary OutFlow Max=O.OO cts @ 0.00 hrs HW=899.40' (Free Discharge) L2=Orifice/Grate (Controls 0.00 cts) L1=Broad-Crested Rectangular Weir ( Controls 0.00 cts) I I 081227 Existing Prepared by Plowe Engineering, Inc. HvdroCAOO 8.50 sin 001574 @2007 HvdroCAD Software Solutions LLC Type 1/24-hr 100-yr Back-la-Back Rainfal/=6.00" x 2 Printed 2/25/2009 Page 12 I Time span=0.00-200.00 hrs, dt=0.01 hrs, 20001 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method I Subcatchment 1: To Lake Runoff Area=295,176 sl 9.26% Impervious Runoff Depth=7.32" Flow Length=625' Tc=18.3 min CN=65 Runoff=33.57 cis 179,969 cf Subcatchment 2: To Wetland Runoff Area=289,267 sl 10.84% Impervious Runoff Depth=7.46" Flow Length=300' Slope=0.0520 'f Tc=17.5 min CN=66 Runoff=33.97 cis 179,932 cl I Pond ExW: Exist Wetland Peak Elev=907.01' Storage=179,859 cl Inflow=33.97 cis 179,932 cf Outflow=0.04 cis 913 cl I Total Runoff Area = 584,443 sf Runoff Volume = 359,901 cf Average Runoff Depth =7.39" 89.96% Pervious = 525,771 sf 10.04% Impervious = 58,672 sf I I I I I I I I I I I I I I I 081227 Existing Prepared by Plowe Engineering, Inc. HvdroCAOO'S.50 sin 001574 @2007 HvdroCAD Software Solutions LLC Type" 24-hr 100~yr Back-fa-Back Rainfal/=6.00" x 2 Printed 2/25/2009 PallA 13 I I Runoff ~ummary for Subcatchment 1: To Lake Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs Type II 24-hr 100-yr Back-to-Back Rainfall=6.00" x 2 33.57 cfs @ 36.09 hrs, Volume= 179,969 cf, Depth= 7.32" I I Area (sf) 13,695 13,630 8,830 259,021 295,176 267,851 27,325 CN Description 98 Roof 98 Bituminous/Concrete Drive 85 Gravel Drive 61 >75% Grass cover, Good, HSG B 65 Weighted Average Pervious Area Impervious Area I Tc Length Slope Velocity Capacity Description (min) (feet) (ftlfl) (ft/sec) (cfs) 16.9 300 0.0567 0.30 Sheet Flow, Grass: Short n= 0.150 P2= 2.70" 1.4 325 0.0635 3.78 Shallow Concentrated Flow, Grassed Waterway Kv= 15.0 fps 18.3 625 Total I I Runoff Summary for Subcatchment 2: To Wetland 33.97 cfs @ 36.09 hrs, Volume= 179,932 cf, Depth= 7.46" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs Type II 24-hr 100-yr Back-to-Back Rainfall=6.00" x 2 I I I Area (sf) 11,707 4,500 6,500 8,150 8,640 8,872 240,898 289,267 257,920 31,347 CN Description 98 Existing Roof 98 Existing Cone. Drive 98 Existing Bil. Drive 85 Existing Gravel Drive 98 Existing Bil. Trail 85 Wetland 61 >75% Grass cover. Good. HSG B 66 Weighted Average Pervious Area Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ftlfl) (ft/sec) (cfs) 17.5 300 0.0520 0.29 Sheet Flow, Grass: Short n= 0.150 P2= 2.70" I I Inflow Area = Inflow Outflow Primary Summary for Pond ExW: Exist Wetland 289,267 sf, 10.84% Impervious, 33.97 cfs @ 36.09 hrs, Volume= 0.04 cfs @ 48.45 hrs, Volume= 0.04 cfs @ 48.45 hrs, Volume= Inflow Depth = 7.46" for 100-yr Back-to-Back event 179,932 cf 913 cf, Allen= 100%, Lag= 741.7 min 913 cf I Routing by Dyn-Stor-Ind method, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs Peak Elev= 907.01'@48.45hrs Surf.Area= 64,406 sf Storage= 179,859 cf Plug-Flow detention time= 2,882.6 min calculated for 913 cf (1 % of inflow) Center-of-Mass del. time= 1,796.8 min (3,545.5 - 1,748.7) I I I I Volume #1 Elevation (feet) 899.40 902.00 904.00 910.00 Device #1 RoutinlJ Device 2 Invert 899.40' Avail.StoralJe StoralJe Description 425,394 cf Custom Stage Data (Prismatic) Listed below (Recalc) #2 Primary Surf.Area (sq-fl) o 4,954 28,500 100,000 Cum. Store (cubic-feet) o 6,440 39,894 425,394 I nc. Store (cubic-feet) o 6,440 33,454 385,500 Invert Outlet Devices 907.00' 10.0' long x 8.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0,60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coet. (English) 2.43 2.54 2.70 2.69 2.68 2.68 2.66 2.64 2.64 2.64 2.65 2.65 2.66 2.66 2.68 2.70 2.74 906.49' 2.00' x 3.00' Horiz. Orifice/Grate Limited to weir flow C= 0.600 Primary OutFlow Max=0.04 cfs @ 48.45 hrs HW=907.01' (Free Discharge) L2=Orifice/Grate (Passes 0.04 cfs of 12.37 cfs potential flow) L1=Broad-Crested Rectangular Weir (Weir Controls 0.04 cfs @ 0.28 fps) I I I I I I I I I I I I I I I I I I I I <1) Direct to Lake @ ~~ ~~~ ~.....................................;.... ~ To Pond Pond Exist Wetland To Wetland ~u~c~ B A ~ Drainage Diagram for 081227 Proposed REV#2 (Pond on L282) Prepared by Plowe Engineering, Inc., Printed 2/25/2009 HydroCAD@ 8.50 sIn 001574 @ 2007 HydroCAD Software Solutions LLC I 081227 Proposed REV#2 (Pond on L2B2) Prepared by Plowe Engineering, Inc. HydroCA[)@8.50 sin 001574 @2007 HydroCAD Software Solutions LLC Type /I 24-hr 2-year (2.80'? Rainfal/=2.80" Printed 2/25/2009 Page 2 I Time span=0.00-200.00 hrs, dt=0.01 hrs, 20001 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method I Subcatchment 1: Direct to Lake Runoff Area=263,439 sf 14.42% Impervious Runoff Depth=0.45" Flow Length=625' Te=18.3 min CN=66 Runoff=2.36 efs 9.934 ef Subcatchment 2: To Wetland Runoff Area=196,729 sf 11.76% Impervious Runoff Depth=0.45" Flow Length=255' Te=8.0 min CN=66 Runoff=2.81 efs 7,418 ef I Subcatchment3: To Pond Runoff Area=124,121 sf 35.04% Impervious Runoff Depth=0.78" Te=7.0 min CN=74 Runoff=3.74 efs 8,109 ef I Pond ExW: Exist Wetland Peak Elev=902.89' Storage=15,515 ef Inflow=3.15 efs 15,515 ef Outflow=O.OO efs 0 ef Pond P: Pond Peak Elev=906.54' Slorage=12,186 ef Inflow=3.74 efs 8,109 cf Outflow=0.51 efs 8,097 ef I Total Runoff Area = 584,289 sf Runoff Volume = 25,461 cf Average Runoff Depth = 0.52" 82.09% Pervious = 479,670 sf 17.91% Impervious = 104,619 sf I I I I I I I I I I I I I I I 081227 Proposed REV#2 (Pond on L282) Prepared by Plowe Engineering, Inc. HvdroCAOO 8.50 sin 001574 @2007 HvdroCAD Software Solutions LLC Type //24-hr 2-year (2.80'? Rainfal/=2.80" Printed 2/25/2009 Page 3 Runoff I Summary for Subcatchment 1: Direct to Lake 2.36 cfs @ 12.14 hrs, Volume= 9,934 cf, Depth= 0.45" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs Type II 24-hr 2-year (2.80") Rainfall=2.80" Tc Length Slope Velocity Capacity Description (min) (feet) (fUft) (fUsee) (cfs) 16.9 300 0.0567 0.30 Sheet Flow, Grass: Short n= 0.150 P2= 2.70" 1.4 325 0.0635 3.78 Shallow Concentrated Flow, Grassed Waterway Kv= 15.0 fps 18.3 625 Total I Area (sf) 4,276 2,250 9,980 8,631 12,849 225,453 263,439 225,453 37,986 I I I I Runoff CN Description 98 Existing Roof 98 Existing Cone. Drive 98 Existing Bit. Drive 98 Proposed Drive 98 Proposed Roof 61 >75% Grass cover. Good, HSG B 66 Weighted Average Pervious Area Impervious Area Summary for Subcatchment 2: To Wetland 2.81 cfs @ 12.02 hrs, Volume= 7,418 ct, Depth= 0.45" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs Type II 24-hr 2-year (2.80") Rainfall=2.80" I Area (sf) 7,500 4,500 6,500 4,640 8,872 164,717 196,729 173,589 23,140 I I CN Description 98 Existing Roof 98 Existing Cone. Drive 98 Existing Bit. Drive 98 Existing Bit. Trail 85 Existing Wetland 61 >75% Grass cover. Good, HSG B 66 Weighted Average Pervious Area Impervious Area I Tc Length Slope Velocity Capacity Description (min) (feet) (fUft) (fUsee) (cfs) 7.3 125 0.0800 0.28 Sheet Flow, Grass: Short n= 0.150 P2= 2.70" 0.7 130 0.0384 2.94 Shallow Concentrated Flow, Grassed Waterway Kv= 15.0 fps 8.0 255 Total I Runoff Summary for Subcatchment 3: To Pond 3.74 cfs @ 11.99 hrs, Volume= 8,109 cf, Depth= 0.78" I Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs Type II 24-hr 2-year (2.80") Rainfall=2.80" I Area (sf) 17,950 9,000 4,800 3,000 4,000 4,743 80.628 124,121 80,628 43,493 I I T c Length (min) (feet) 7.0 I Inflow Area = Inflow Outflow Primary I CN Description 98 Proposed Road 98 Proposed Roof 98 Proposed Drive 98 Existing Roof 98 Exisitng Bit. Trail 100 Pond NWL 61 >75% Grass cover, Good. HSG B 74 Weighted Average Pervious Area Impervious Area Slope Velocity Capacity Description (fUft) (fUsee) (cfs) Direct Entry, Summary for Pond ExW: Exist Wetland 320,850 sf, 20.77% Impervious, 3.15 cfs @ 12.02 hrs, Volume= 0.00 cfs @ 0.00 hrs, Volume= 0.00 cfs @ 0.00 hrs, Volume= Inflow Depth = 0.58" for 2-year (2.80") event 15,515 cf o cf, Allen= 100%, Lag= 0.0 min o cf I Type 1/24-hr 2-year (2.80'? Rainfal/=2.80" Printed 2/25/2009 Page 4 081227 Proposed REV#2 (Pond on L282) Prepared by Plowe Engineering, Inc. HvdroCAOO 8.50 sin 001574 @ 2007 HVdroCAD Software Solutions LLC I Routing by Dyn-Stor-Ind method, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs Peak Elev= 902.89' @ 200'.00 hrs Surf.Area= 15,435 sf Storage= 15,515 cf I Plug-Flow detention time= (not calculated; initial storage excedes outflow) Center-of-Mass del. time= (not calculated; no outflow) Volume #1 Invert 899.40' Avail.StoraQe StoraQe Description 425,394 cf Custom Stage Data (Prismatic) Listed below (Recalc) I Elevation (feet) 899.40 902.00 904.00 910.00 Surf. Area (SQ-ft) o 4,954 28,500 100,000 Inc. Store (cubic-feet) o 6,440 33,454 385,500 Cum. Store (cubic-feet) o 6,440 39,894 425,394 I Device #1 Routino Device 2 Invert Outlet Devices 907.00' 10.0' long x 8.0' breadth Broad-Crested Rectangular Weir . Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.43 2.54 2.70 2.69 2.68 2.68 2.66 2.64 2.64 2.64 2.65 2.65 2.66 2.66 2.68 2.70 2.74 906.49' 2.00' x 3.00' Horiz. Orifice/Grate Limited to weir flow C= 0.600 I #2 Primary Primary OutFlow Max=O.OO cfs @ 0.00 hrs HW=899.40' (Free Discharge) Lt.orifice/Grate (Controls 0.00 cfs) 1=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) I Summary for Pond P: Pond I 124,121 sf, 35.04% Impervious, 3.74cfs@ 11.99hrs, Volume= 0.51 cfs @ 12.39 hrs, Volume= 0.51 cfs @ 12.39 hrs, Volume= Inflow Area = Inflow Outflow Primary Inflow Depth = 0.78" for 2-year (2.80") event 8,109 cf 8,097 cf, Alten= 86%, Lag= 23.7 min 8,097 cf I Routing by Dyn-Stor-Ind method, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs Starting Elev= 906.00' Surf.Area= 4,911 sf Storage= 9,348 cf Peak Elev= 906.54' @ 12.39 hrs Surf.Area= 5,572 sf Storage= 12,186 cf (2,838 cf above start) I Plug-Flow detention time= (not calculated; initial storage excedes outflow) Center-of-Mass del. time= 161.5 min ( 1,030.2 - 868.7) Avail.Storaoe Storaoe Description 34,188 cf Custom Stage Data (Prismatic) Listed below (Recalc) Volume #1 Invert 901.00' I Elevation (feet) 901.00 903.00 905.00 906.00 908.00 909.00 909.50 Surf.Area (SQ-ft) 573 1,359 2,401 4,911 7,352 8,720 9,442 Inc. Store (cubic-feet) o 1,932 3,760 3,656 12,263 8,036 4,541 Cum. Store (cubic-feet) o 1,932 5,692 9,348 21,611 29,647 34,188 I I Outlet Devices 6.0" Vert. Orifice/Grate C= 0.600 15.0" x 21.0' long Culvert Ke= 0.500 Outlet Invert= 904.00' S= 0.0119 '/' Cc= 0,900 n= 0.012 10.0' long x 5.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.34 2.50 2.70 2.68 2.68 2.66 2.65 2.65 2.65 2.65 2.67 2.66 2.68 2.70 2.74 2.79 2.88 Primary OutFlow Max=0.51 cfs@ 12.39 hrs HW=906.54' TW=901.22' (Dynamic Tailwater) t2=culvert (Passes 0.51 cfs of 7.63 cfs potential flow) L1=Orifice/Grate (Orifice Controls 0.51 cfs @ 2.60 fps) 3=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Device #1 #2 #3 Routino Device 2 Primary Primary Invert 906.00' 904.25' 908.50' I I I I I I I 081227 Proposed REV#2 (Pond on L282) Prepared by Plowe Engineering, Inc. HvdroCA[)@8.50 sin 001574 @ 2007 HvdroCAD Software Solutions LLC Type 1/ 24-hr 10"Event Rainfal/=10.00" Printed 2/25/2009 P"IlA 5 I Time span=0.00-200.00 hrs, dt=0.01 hrs, 20001 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method I Subcatchment 1: Direct to Lake Runoff Area=263,439 sf 14.42% Impervious Runoff Depth=5.70" Flow Length=62S' Tc=18.3 min CN=66 Runoff=40.34 cfs 125,078 cf Subcatchment2: To Wetland RurlOff Area=196,729 sf 11.76% Impervious Runoff Depth=5.70" Flow Length=255' Tc=8.0 minCN=66 Runoff=42.39 cfs 93,40S cf I Subcatchment3: To Pond Runoff Area=124,121 sf 35.04% Impervious Runoff Deplh=6.75" Tc=7.0 mln CN=74 Runoff=32.06 cfs 69,791 cf I Pond ExW: Exist Wetland Peak Eiev=906.69' Storage=159,565 cf Inftow=61.04 cfs 159,565 cf Ouffiow=O.OO cfs 0 cf Pond P: Pond Peak Etev=909.34' Slorage=32,657 cf Inftow=32.06 cfs 69,791 cf Ouffiow=22.14 cfs 66,159 cf I Total Runoff Area = 584,289 sf Runoff Volume = 288,275 cf Average Runoff Depth = 5.92" 82.09% Pervious = 479,670 sf 17.91% Impervious = 104,619 sf I I I I I I I I I I I I I I 081227 Proposed REV#2 (Pond on L2B2) Prepared byPlowe Engineering, Inc. HydroCA[)@8,50 sin 001574 @2007 HydroCAD Softwar~ Solutions LLC Type /I 24-hr 10" Event Rainfal/=10.00" Printed 2/25/2009 Page 6 I Runoff I Summary for Subcatchment 1: Direct to Lake 40.34 cfs @ 12.1 () hrs, Volume= 125,078 cf, Depth= 5.70" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs,dt= 0.01 hrs Type II 24-hr 10" Event Rainfall=10.00" Tc Length Slope Velocity Capacity. Description (min) (feetl (ft/ft) (ft/sec) (cfs) 16.9 300 0.0567 0.30 Sheet Flow, Grass: Short n= 0.150 P2= 2.70" 1.4 325 0.0635 3.78 Shallow Concentrated Flow, Grassed Waterway Kv= 15.0 fps 18.3 625 Total I Area (sf) 4,276 2,250 9,980 8,631 12,849 225.453 263.439 225,453 37,986 I I I I Runoff CN Description 98 Existing Roof 98 Existing Cone. Drive 98 Existing Bit. Drive 98 Proposed Drive 98 Proposed Roof 61 >75% Grass cover, Good, HSG B 66 Weighted Average Pervious Area Impervious Area Summary for Subcatchment 2: To Wetland 42.39 cfs @ 11.99 hrs, Volume= 93,405 cf, Depth= 5.70" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs Type II 24-hr 10" Event Rainfall=10.00" I Area (sf) 7,500 4,500 6,500 4,640 8,872 164,717 196,729 173,589 23,140 I I CN Description 98 Existing Roof 98 Existing Cone. Drive 98 Existing Bit. Drive 98 Existing Bit. Trail 85 Existing Wetland 61 >75% Grass cover. Good, HSG B 66 Weighted Average Pervious Area Impervious Area I Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.3 125 0.0800 0.28 Sheet Flow, Grass: Short n= 0.150 P2= 2.70" 0.7 130 0.0384 2.94 Shallow Concentrated Flow, Grassed Waterway Kv= 15.0 fps 8.0 255 Total I Runoff Summary for Subcatchment 3: To Pond 32.06 cfs @ 11.98 hrs, Volume= 69,791 cf, Depth= 6.75" I Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs Type II 24-hr 10" Event Rainfall=10.00" I Area (sf) 17,950 9,000 4,800 3,000 4,000 4,743 80,628 124,121 80,628 43.493 I I T c Length (min) (feet) 7.0 I CN Description 98 Proposed Road 98 Proposed Roof 98 Proposed Drive 98 Existing Roof 98 Exisitng Bit. Trail 100 Pond NWL 61 >75% Grass cover. Good, HSG B 74 Weighted Average Pervious Area Impervious Area Slope Velocity Capacity Description (ft/ft) (ft/sec) (cfs) Direct Entry, [80] Warning: Exceeded Pond P by 0.01' @ 199.99 hrs (0.08 cfs 35,133 cf) Summary for Pond ExW: Exist Wetland I I Type 1/24-hr 10" Event Rainfal/=10.00" Printed 2/25/2009 PaoP. 7 081227 Proposed REV#2 (Pond on L2B2) Prepared by Plowe Engineering, Inc. HydroCAD@8.50 sin 001574 @2007 HydroCAD Software Solutions LLC I Inflow Depth = 5.97" for 10" Event event 159,565 cf o d, Atten= 100%, Lag= 0.0 min o cf 320,850 sf, 20.77% Impervious, 61.04 cfs@ 12.02 hrs, Volume= 0.00 cfs @ 0.00 hrs, Volume= 0.00 cfs @ 0.00 hrs, Volume= Inflow Area = Inflow Outflow Primary I Routing by Dyn-Stor-Ind method, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs Peak Elev= 906.69' @ 200.00 hrs Surf.Area= 60,534 sf Storage= 159,565 cf Plug-Flow detention time= (not calculated: initial storage excedes outflow) Center-of-Mass del. time= (not calculated: no outflow) I Avail.Storage Storage Description 425,394 cf Custom Stage Data (Prismatic) Listed below (Recalc) Invert 899.40' Volume #1 I Cum. Store (cubic-feet) o 6,440 39,894 425,394 Inc. Store (cubic-feet) o 6,440 33,454 385,500 Surf.Area (sQ-ft) o 4,954 28,500 100,000 Elevation (feet) 899.40 902.00 904.00 910.00 I Outlet Devices 10.0' long x 8.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1,20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.43 2.54 2.70 2.69 2.68 2.68 2.66 2.64 2.64 2.64 2.65 2.65 2.66 2.66 2.68 2.70 2.74 2.00' x 3.00' Horiz. Orifice/Grate Limited to weir flow C= 0.600 Invert 907.00' Routing Device 2 Device #1 I 906.49' Primary #2 Primary OutFlow Max=O.OO cfs @ 0.00 hrs HW=899.40' (Free Discharge) L2=Orifice/Grate (Controls 0.00 cfs) L1=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) I Summary for Pond P: Pond I Inflow Depth = 6.75" for 10" Event event 69,791 cf 66,159 cf, Alten= 31%, Lag= 4.1 min 66,159 cf 124,121 sf, 35.04% Impervious, 32.06 cfs @ 11.98 hrs, Volume= 22.14 ds @ 12.05 hrs, Volume= 22.14cfs@ 12.05hrs, Volume= Inflow Area = Inflow Outflow Primary I Routing by Dyn-Stor-Ind method, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs Starting Elev= 906.00' Surf.Area= 4,911 sf Storage= 9,348 cf Peak Elev= 909.34'@ 12.05 hrs Surf.Area= 9,205 sf Storage= 32.657 cf (23,309 cfabove start) Plug-Flow detention time= 189.8 min calculated for 56,811 cf (81% of inflow) Center-of-Mass del. time= 78.7 min (883.9 - 805.2) I Avail.Storage Storage Description 34,188 cf Custom Stage Data (Prismatic) Listed below (Recalc) Volume #1 Invert 901.00' I Cum.Store (cubic-feet) o 1,932 5,692 9,348 21,611 29,647 34,188 Surf.Area (sQcft) 573 . 1,359 2,401 4,911 7,352 8,720 9,442 Inc. Store (cubic-feet) o 1,932 3,760 3,656 12,263 8,036 4,541 Elevation (feet) 901.00 903.00 905.00 906.00 908.00 909.00 909.50 I I Invert Outlet Devices 906.00' 6.0" Vert. Orifice/Grate C= 0.600 904.25' 15.0" x 21.0' long Culvert Ke= 0.500 Outlet Invert= 904.00' S= 0.0119 'f' Cc= 0.900 n= 0.012 908.50' 10.0' long x 5.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.34 2.50 2.70 2.68 2.68 2.66 2.65 2.65 2.65 2.65 2.67 2.66 2.68 2.70 2.74 2.79 2.88 Primary OutFlow Max=22.14 cfs @ 12.05 hrs HW=909.34' TW=904.35' (Dynamic Tailwater) t2=culvert (Passes 1.66 cfs of 12.48 cfs potential flow) L1=Orifice/Grate (Orifice Controls 1.66 cfs @ 8.46 fps) 3=Broad-Crested Rectangular Weir (Weir Controls 20.48 cfs @ 2.45 fps) Routing Device 2 Primary Primary Device #1 #2 #3 I I I I I I 081227 Proposed REV#2 (Pond on L282) Prepared by Plowe Engineering, Inc. HvdroCA[)@8.50 sIn 001574 @2007 HvdroCAD Software Solutions llC Spillway 1-day 10-day 10cday Snowmelt Rainfall=7.20",AMC=4 Printed 2/25/2009 Page 8 I I Subcatchment 1: Direct to Lake Subcatchment2: To Wetland I Subcatchment3: To Pond I Pond ExW: Exist Wetland Pond P: Pond I I I I I I I I I I I I I I Time span=0.00-200.00 hrs, dt=0.01 hrs, 20001 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method Runoff Area=263,439 sf 14.42% Impervious Runoff Depth>6.47" Flow length=625' . Tc=18.3 min Adjusted CN=98 Runoff=2.85 cfs 142,116 cf Runoff Area=196,729 sf 11.76% Impervious Runoff Depth>6.48" Flow length=255' Tc=8.0 min Adjusted CN=98 Runoff=2.16 cts 106,169 ct Runoff Area=124,121 sf 35,04% Impervious Runoff Depth>6.48" . Tc=7.0 min Adjusted CN=98 Runoff=1.37 cts 66,987 cf Peak Elev=906.84' Storage~168,616 ct Inflow=2.92 cfs 168,618 ct OutfJow=O.OO cts (j ct Peak Elev=907.11' Storage=15,547 ct Inflow=1.37 cfs 66.987 ct OutfJow=0.88 cts 62,449 cf Total Runoff Area = 584,289 sf Runoff Volume = 315,271 cf Average Runoff Depth = 6.47" 82.09% Pervious = 479,670 sf 17.91% Impervious = 104,619 sf I I 081227 Proposed REV#2 (Pond on L2B2) Prepared by Plowe Engineering, Inc. HydroCAOO 8:50 sin 001574 @2007 HydroCAD Software Solutions LLC Spillway 1-day 10-day 10-day Snowmelt Rainfal/=7.20", AMC=4 Printed 2/25/2009 PaQe 9 Runoff I Summary for Subcatchment 1: Direct to Lake 2.85 cfs @ 121.49 hrs, Volume= 142,116 ct, Depth> 6.47" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs Spillway 1-day 10-day 10-day Snowmelt Raintall=7.20", AMC=4 Ie Length Slope Velocity Capacity Description . (min) (feet) (ft/ft) (ft/sec ) (cfs) 16.9 300 0.0567 0.30 Sheet Flow, Grass: Short n= 0.150 P2= 2.70" 1.4 325 0.0635 3.78 Shallow Concentrated Flow, Grassed Waterway Kv= 15.0 fps 18.3 625 Total I Area (sf) 4,276 2,250 9,980 8,631 12,849 225.453 263,439 225.453 37,986 I I I I Runoff CN Description 98 Existing Roof 98 Existing Cone. Drive 98 Existing Bit. Drive 98 Proposed Drive 98 Proposed Roof 61 >75% Grass cover, Good, HSG B 66 Weighted Average, Adjusted for AMC to CN = 98 Pervious Area Impervious Area Summary for Subcatchment 2: To Wetland 2.16 cfs@ 121.34 hrs, Volume= 106,169 cf, Depth> 6.48" I Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs Spillway 1-day 10-day 10-day Snowmelt Rainfall=7.20", AMC=4 I Area (sf) 7,500 4,500 6,500 4,640 8,872 164,717 196,729 173,589 23,140 I CN Description 98 Existing Roof 98 Existing Cone. Drive 98 Existing Bit. Drive 98 Existing Bit. Trail 85 Existing Wetland 61 >75% Grass cover, Good, HSG B 66 Weighted Average, Adjusted for AMC to CN = 98 Pervious Area Impervious Area I Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.3 125 0.0800 0.28 Sheet Flow, Grass: Short n= 0.150 P2= 2.70" 0.7 130 0.0384 2.94 Shallow Concentrated Flow, Grassed Waterway Kv= 15.0 fps 8.0 255 Total I Runoff I Summary for Subcatchment 3: To Pond 1.37 cfs@ 121.31 hrs, Volume= 66,987 ct, Depth> 6.48" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs Spillway 1-day 10-day 10-day Snowmelt Rainfall=7.20", AMC=4 I Area (sf) 17,950 9,000 4,800 3,000 4,000 4,743 80,628 124,121 80,628 43,493 I I Tc Length (min) (feet) 7.0 I Inflow Area = Inflow Outflow Primary I CN Description 98 Proposed Road 98 Proposed Roof 98 Proposed Drive 98 Existing Roof 98 Exisitng Bit. Trail 100 Pond NWL 61 >75% Grass cover, Good. HSG B 74 Weighted Average, Adjusted for AMC to CN = 98 Pervious Area . Impervious Area Slope Velocity Capacity Description (ft/ft) (ft/sec) (cfs) Direct Entry, Summary for Pond ExW: Exist Wetland 320,850 sf, 20.77% Impervious, 2.92 cfs@ 121.36 hrs, Volume= 0.00 cfs @ 0.00 hrs, Volume= 0.00 cts @ 0.00 hrs, Volume= Inflow Depth> 6.31" for 10-day Snowmelt event 168,618 cf o cf, Allen= 100%, Lag= 0.0 min o cf I Spillway 1-day 10-day 10-day Snowmelt RainfaJ/=7.20': AMC=4 Printed 2/25/2009 Page 10 081227 Proposed REV#2 (Pond on L2B2) Prepared by Plowe Engineering, Inc. HydroCA[)@'8.50 sin 001574 @2007 HydroCAD Software Solutions LLC I Routing by Dyn-Stor-Ind method, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs Peak Elev= 906.84' @ 200.00 hrs Surf.Area= 62,291 sf Storage= 168,616 cf I Plug-Flow detention time= (not calculated: initial storage excedes outflow) Center-of-Mass del. time= (not calculated: no outflow) Avail.StoraQe StoraQe Description 425,394 cf Custom Stage Data (Prismatic) Listed below (Recalc) Invert 899.40' Volume #1 I Cum.Store ( cubic-feet) o 6,440 39,894 425,394 Inc. Store (cubic-feet) o 6,440 33,454 385,500 Surf. Area (sq-ft) o 4,954 28,500 100,000 Elevation (feet) 899.40 902.00 904.00 910.00 I Outlet Devices 10.0' long x 8.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.504.00 4.50 5.00 5.50 Coef. (English) 2.43 2.54 2.70 2.69 2.68 2.68 2.66 2.64 2.64 2.64 2.65 2.65 2.66 2.66 2.68 2.70 2.74 2.00' x 3.00' Horiz. Orifice/Grate Limited to weir flow C= 0.600 RoutinQ Device 2 Invert 907.00' Device #1 I 906.49' #2 Primary Primary OutFlow Max=O.OOcfs @ 0.00 hrs HW=899.40' (Free Discharge) "L.t.Orifice/Grate (Controls 0.00 cfs) 1=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) I Summary for Pond P: Pond I [87] Warning: Oscillations may require Finer Routing or smaller dt Inflow Depth> 6.48" for 10-daySnowmelt event 66,987 cf 62,449 cf, Allen= 36%, Lag= 78.6 min 62,449 cf 124,121 sf, 35.04% Impervious, 1.37 cfs @ 121.31 hrs, Volume= 0.88 cfs @ 122.62 hrs, Volume= 0.88 cfs @ 122.62 hrs, Volume= Inflow Area = Inflow Outflow Primary I Routing by Dyn-Stor-Ind method, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs Starting Elev= 906.00' Surf.Area= 4,911 sf Storage= 9,348 cf Peak Elev= 907.11' @ 122.62 hrs Surf.Area= 6,265 sf Storage= 15,547 cf (6,199 cf above start) I Plug-Flow detention time= 1,413.7 min calculated for 53,101 cf (79% of inflow) Center-of-Mass del. time= (not calculated: outflow precedes inflow) I Avail.StoraQe StoraQe Description 34,188 cf Custom Stage Data (Prismatic) Listed below (Recalc) Invert 901.00' Volume #1 Cum. Store (cubic-feet) o 1,932 5,692 9,348 21,611 29,647 34,188 Inc. Store (cubic-feet) o 1,932 J,760 3,656 12,263 8,036 4,541 Surf.Area (Sq-ft) 573 1,359 2,401 4,911 7,352 8,720 9,442 Elevation (feet) 901.00 903.00 905.00 906.00 908.00 909.00 909.50 I I Outlet Devices 6.0" Vert. Orifice/Grate C= 0.600 15.0" x 21.0' long Culvert Ke= 0.500 Outlet Invert= 904.00' S= 0.0119 '/' Cc= 0.900 n= 0.012 10.0' long x 5.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.34 2.50 2.70 2.68 2.68 2.66 2.65 2.65 2.65 2.65 2.67 2.66 2.68 2.70 2.74 2.79 2.88 Primary OutFlow Max=0.88 cfs @ 122.62 hrs HW=907.11' TW=905.49' (Dynamic Tailwater) tt.culvert (Passes 0.88 cfs of 7.51 cfs potential flow) 1=Orifice/Grate (Orifice Controls 0.88 cfs @ 4.46 fps) 3=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Invert 906.00' 904.25' 908.50' Device #1 #2 #3 RoutinQ Device 2 Primary Primary I I I I I I I I 081227 Proposed REV#2 (Pond on L282) Prepared by Plowe Engineering, Inc. HydroCAD@8.50 sin 001574 @2007 HydroCAD Software Solutions LLC Type 1/24-hr to-year (4.20'; Rainfal/=4.20" Printed 2/25/2009 Page 11 Time span=0.00-200.00 hrs, dt=0.01 hrs, 20001 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method I Subcatchment 1: Direct to Lake Runoff Area=263,439 Sf 14.42% Impervious Runoff Depth=1.21" Flow Length=625' Tc=18.3 min CN=66 Runoff=7.93 cfs 26,506 cf Subcatchment 2: To Wetland Runoff Area=196,729 sf 11.76% Impervious Runoff Depth=1.21" Flow Lenglh=255' Tc=8.0 min CN=66 Runoff=8.79 cfs 19,794 cf I Subcatchment3: To Pond Runoff Area=124, 121 sf 35.04% Impervious Runoff Depth=1.74" Tc=7.0 min CN=74 Runoff=8.58 cfs 18,045 cf I Pond ExW: Exist Wetland Peak Elev=903.93' Storage=37,827 cf Inflow=9.58 cfs 37,827 cf Outflow=O.OO cfs 0 cf Pond P: Pond Peak Elev=907.32' Storage=16,879 cf Inflow=8.58 cfs 18,045 cf Outflow=0.98 cfs 18,033 cf I Total Runoff Area = 584,289 sf Runoff Volume = 64,345 cf Average Runoff Depth = 1.32" 82.09% Pervious = 479,670 sf 17.91% Impervious = 104,619 sf I I I I I I I I I I I I I I 081227 Proposed REV#2 (Pond on L282) Prepared by Plowe Engineering, Inc. HydroCA0@8.50 sin 001574 @2007 HydroCAD Software Solutions LLC Type /I 24-hr to-year (4.20'? RainfaJ/=4.20" Printed 2/25/2009 P"'Qe 1? I Runoff I Summary for Subcatchment 1: Direct to Lake 7.93 cfs @ 12.12 hrs, Volume= 26,506 ct, Depth= 1.21" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt=0.01 hrs Type II 24-hr 10-year (4.20") Rainfall=4.20" Tc Length Slope Velocity Capacity Description (min) (feet) (ftlft) (ftlsec) (cts) 16.9 300 0.0567 0.30 Sheet Flow, Grass: Short n= 0.150 P2= 2.70" 1.4 325 0.0635 3.78 Shallow Concentrated Flow, Grassed Waterway Kv= 15.0 fps 18.3 625 Total I Area (sf) 4,276 2,250 9,980 8,631 12,849 225.453 263,439 225,453 37,986 I I I I Runoff CN Description 98 Existing Roof 98 Existing Cone. Drive 98 Existing Bit. Drive 98 Proposed Drive 98 Proposed Roof 61 >75% Grass cover. Good. HSG B 66 Weighted Average Pervious Area Impervious Area Summary for Subcatchment 2: To Wetland 8.79 cts @ 12.01 hrs, Volume= 19,794 ct, Depth= 1.21" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs Type II 24-hr 10-year (4.20") Rainfall=4.20" Tc Length Slope Velocity Capacity Description (min) (feet) (ftlft) (ftlsec) (cfs) 7.3 125 0.0800 0.28 Sheet Flow, Grass: Short n= 0.150 P2= 2.70" 0.7 130 0.0384 2.94 Shallow Concentrated Flow, Grassed Waterway Kv= 15.0 fps 8.0 255 Total I Area (sf) 7,500 4,500 6,500 4.640 8,872 164,717 196,729 173,589 23,140 I I I I Runoff CN Description 98 Existing Roof 98 Existing Cone. Drive 98 Existing Bit. Drive 98 Existing Bit. Trail 85 Existing Wetland 61 >75% Grass cover. Good, HSG B 66 Weighted Average Pervious Area Impervious Area Summary for Subcatchment 3: To Pond 8.58 cfs @ 11.99 hrs, Volume= 18,045 cf, Depth= 1.74" I Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs Type II 24-hr 10-year (4.20") Rainfall=4.20" I Area (sf) 17,950 9,000 4,800 3,000 4,000 4,743 80.628 124,121 80,628 43,493 I I Tc Length (min) (feet) 7.0 I Inflow Area = Inflow Outflow Primary I CN Description 98 Proposed Road 98 Proposed Roof 98 Proposed Drive 98 Existing Roof 98 Exisitng Bit. Trail 100 Pond NWL 61 >75% Grass cover. Good, HSG B 74 Weighted Average Pervious Area Impervious Area Slope Velocity Capacity Description (ftlft) (ftlsec) (cfs) Direct Entry, Summary for Pond ExW: Exist Wetland 320,850 sf, 20.77% Impervious, 9.58 cts @ 12.01 hrs, Volume= 0.00 cfs @ 0.00 hrs, Volume= 0.00 cfs @ 0.00 hrs, Volume= Inflow Depth = 1.41" for 10-year (4.20") event 37,827 cf o cf, Atten= 100%, Lag= 0.0 min oct I Type 1/24-hr to-year (4.20'1 Rainfal/=4.20" Printed 2/25/2009 P~ge 13 081227 Proposed REV#2 (Pond on L282) Prepared by Plowe Engineering, Inc. HvdroCAOO 8.50 sin 001574 @2007 HvdroCAD Software Solutions LLC I. Routing by Dyn-Stor-Ind method, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs Peak Elev= 903.93' @ 200.00 hrs Surf.Area= 27.633 sf Storage= 37,827 cf I Plug-Flow detention time= (not calculated: initial storage excedes outflow) Center-of-Mass del. time= (not calculated: no outflow) Avail.StoraQe StoraQe Description 425,394 cf Custom Stage Data (Prismatic) Listed below (Recalc) Volume #1 Invert 899.40' I Inc. Store (cubic-feet) o 6,440 33,454 385,500 Cum. Store (cubic-feet) o 6,440 39,894 425,394 Elevation (feet) 899.40 902.00 904.00 910.00 Surf. Area (Sq-ft) o 4,954 28,500 100,000 I Invert Outlet Devices 907.00' 10.0' long x 8.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.201.401.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.43 2.54 2.70 2.69 2.68 2.68 2.66 2.64 2.64 2.64 2.65 2.65 2.66 2.66 2.68 2.70 2.74 906.49' 2.00' x 3.00' Horiz. Orifice/Grate Limited to weir flow C= 0.600 Device #1 RoutinQ Device 2 I #2 Primary Primary OutFlow Max=O.OO cfs @ 0.00 hrs HW=899.40' (Free Discharge) L2=Orifice/Grate (Controls 0.00 cfs) L1=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) I Summary for Pond P: Pond I Inflow Depth = 1.74" for 10-year (4.20") event 18,045 cf 18,033 cf, Atten= 89%, Lag= 26.5 min 18,033 cf 124,121 sf, 35.04% Impervious, 8.58 cfs @ 11.99 hrs, Volume= 0.98 cfs @ 12.43 hrs, Volume= 0.98 cfs @ 12.43 hrs, Volume= Inflow Area = Inflow Outflow Primary I Routing by Dyn-Stor-Ind method, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs Starting Elev= 906.00' Surf.Area= 4,911 sf Storage= 9,348 cf Peak Elev= 907.32' @ 12.43 hrs Surf.Area= 6,519 sf Storage= 16,879 cf (7,531 cf above start) I Plug-Flow detention time= 457.9 min calculated for 8,685 cf (48% of inflow) Center-of-Mass del. time= 133.9 min ( 977.9 - 844.0) Avail.StoraQe StoraQe Description 34,188 cf Custom Stage Data (Prismatic) Listed below (Recalc) Volume #1 Invert 901.00' I Cum. Store ( cubic-feet) o 1,932 5,692 9,348 21,611 29,647 34,188 Inc. Store (cubic-feet) o 1,932 3,760 3,656 12,263 8,036 4,541 Elevation (feet) 901.00 903.00 905.00 906.00 908.00 909.00 909.50 Surf. Area (Sq-ft) 573 1,359 2,401 4,911 7,352 8,720 9,442 I I Invert Outlet Devices 906.00' 6.0" Vert. Orifice/Grate C= 0.600 904.25' 15.0" x 21.0' long Culvert Ke= 0.500 Outlet Invert= 904.00' S= 0.0119 '/' Cc= 0.900 n= 0.012 908.50' 10.0' long x 5.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.801.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.34 2.50 2.70 2.68 2.68 2.66 2.65 2.65 2.65 2.65 2.67 2.66 2.68 2.70 2.74 2.79 2.88 Primary OutFlow Max=0.98 cfs @ 12.43 hrs HW=907.32' TW=902.54' (Dynamic Tailwater) tt.culvert (Passes 0.98 cfs of 9.24 cfs potential flow) 1=Orifice/Grate (Orifice Controls 0.98 cfs @4.98 fps) 3=Broad-Crested Rectangular Weir (Controls 0.00 cfs) Device #1 #2 #3 RoutinQ Device 2 Primary Primary I I I I I I I 081227 Proposed REV#2 (Pond on L282) Prepared by Plowe Engineering, Inc. HvdroCAD<6> 8.50 sin 001574 @2007 HvdroCAD Software Solutions LLC Type II 24,hr 1 DO-year (6.00") Rainfal/=6.00" Printed 2/25/2009 Page 14 I Time span=0.00-200.00 hrs, dt=0.01 hrs, 20001 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method I Subcatchment 1: Direct to Lake Runoff Area=263,439 sl 14.42% Impervious Runoff Depth=2.44" Flow Length=625' .Tc=18.3 min CN=66 Runoff=16.97 cfs 53,571 cl Subcatchment 2: To Wetland Runoff Area=196,729 sl 11.76% Impervious Runoff Depth=2.44" Flow Length=255' Tc=8.0 min CN=66 Runoff=18.28 cIs 40,005 cl I Subcatchment 3: To Pond RunoffArea=124,121 sl 35.04% Impervious RunoffDepth=3.18" Tc=7.0 min CN=74 Runoff=15.57 cfs 32,943 cl I Pond ExW: Exist Wetland Peak Elev=904.96' Storage=72,936 cl Inflow=19.43 cIs 72,936 cl Oulflow=O.OO cfs 0 cl Pond P: Pond Peak Elev=908.40' Storage=24,648 cl Inflow=15.57 cIs 32,943 cl Oulflow=1.39 cIs 32,931 cl I Total Runoff Area = 584,289 sf Runoff Volume = 126,518 cf Average Runoff Depth = 2.60" 82.09% Pervious = 479,670 sf 17.91% Impervious = 104,619 sf I I I I I I I I I I I I I I 081227 Proposed REV#2 (Pond on L2B2) Prepared by Plowe Engineering, Inc. HvdroCA()@8.50s/n001574 @2007 HvdroCAD Software Solutions LLC Type" 24-hr tOO-year (6.00'? Rainfal/=6.00" Printed 2/25/2009 Page 15 I Runoff I Summary for Subcatchment 1: DirecUo Lake 16.97 cfs @ 12.12 hrs, Volume= 53,571 cf, Depth= 2.44" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs Type II 24-hr 100-year (6.00") Rainfall=6.00" Tc Length Slope Velocity Capacity Description (min) (feet) (fUft) (fUsee) (cfs) 16.9 300 0.0567 0.30 Sheet Flow, Grass: Short n= 0.150 P2= 2.70" 1.4 325 0.0635 3.78 Shallow Concentrated Flow, Grassed Waterway Kv= 15.0 fps 18.3 625 Total I Area (sf) 4,276 2,250 9,980 8,631 12,849 225.453 263.439 225.453 37,986 * . I I I I Runoff CN Description 98 Existing Roof 98 Existing Cone. Drive 98 Existing Bit. Drive 98 Proposed Drive 98 Proposed Roof 61 >75% Grass cover, Good, HSG B 66 Weighted Average Pervious Area Impervious Area Summary for Subcatchment 2: To Wetland 18.28 cts @ 12.00 hrs, Volume= 40,005 cf, Depth= 2.44" I Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs Type II 24-hr 100-year (6.00") Rainfall=6.00" I Area (sf) 7,500 4,500 6,500 4,640 8,872 164,717 196,729 173,589 23,140 I CN Description 98 Existing Roof 98 Existing Cone. Drive 98 Existing Bit. Drive 98 Existing Bit. Trail 85 Existing Wetland 61 >75% Grass cover, Good, HSG B 66 Weighted Average Pervious Area Impervious Area I Tc Length Slope Velocity Capacity Description (min) (feet) (fUft) (fUsee) (cfs) 7.3 125 0.0800 0.28 Sheet Flow, Grass: Short n= 0.150 P2= 2.70" 0.7 130 0.0384 2.94 Shallow Concentrated Flow, Grassed Waterway Kv= 15.0 fps 8.0 255 Total I Runoff I Summary for Subcatchment 3: To Pond 15.57 cfs@ 11.99 hrs, Volume= 32,943 cf, Depth= 3.18" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs Type II 24-hr 100-year (6.00") Rainfall=6.00" I Area (sf) 17,950 9,000 4,800 3,000 4,000 4,743 80,628 124,121 80,628 43.493 I I Tc Length (min) (feet) 7.0 I Inflow Area = Inflow Outflow Primary I CN Description 98 Proposed Road 98 Proposed Roof 98 Proposed Drive 98 Existing Roof 98 Exisitng Bit. Trail 100 Pond NWL 61 >75% Grass cover, Good, HSG B 74 Weighted Average Pervious Area Impervious Area Slope Velocity Capacity Description (fUft) (fUsee) (cfs) Direct Entry, Summary for Pond ExW: Exist Wetland 320,850 sf, 20.77% Impervious, 19.43 cfs @ 12.00 hrs, Volume= 0.00 cfs @ 0.00 hrs, Volume= 0.00 cfs @ 0.00 hrs, Volume= Inflow Depth = 2.73" for 100-year (6.00") event 72,936 cf o cf, Allen= 100%, Lag= 0.0 min oct I Type 1/ 24-hr tOO-year (6.00") Rainfal/=6.00" Printed 2/25/2009 Page16 081227 Proposed REV#2 (Pond on L282) Prepared by Plowe Engineering, Inc. HvdroCA[)@8.50 sin 001574 @2007 HvdroCAD Software Solutions LLC I Routing by Dyn-Stor-Ind method, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs Peak Elev= 904.96' @ 200.00 hrs Surf.Area= 39,997 st Storage= 72,936 cf I Plug-Flow detention time=(not calculated: initial storage excedes outflow) Center-ot-Mass del. time= (not calculated: no outflow) Invert 899.40' Avail.StoraQe StoraQe DescriPtion 425,394 ct Custom Stage Data (Prismatic) Listed below (Recalc) Volume #1 I Cum.Store (cubic-teet) o 6,440 39,894 425,394 Elevation (feet) 899.40 902.00 904.00 910.00 Surf. Area (Sq-ft) o 4,954 28,500 100,000 Inc. Store (cubic-feet) o 6,440 33,454 385,500 I Device #1 Routinq Device 2 Invert Outlet Devices 907.00' 10.0' long x 8.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00.1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coet. (English) 2.43 2.54 2.70 2.69 2.68 2.68 2.66 2.64 2.642.64 2.65 2.65 2.66 2.66 2.68 2.70 2.74 906.49' 2.00' x 3.00' Horiz. Orifice/Grate Limited to weir flow C= 0.600 I #2 Primary Primary OutFlow Max=O.OO cfs @ 0.00 hrs HW=899.40' (Free Discharge) Lt.Oi'ifiCeIGrate (Controls 0.00 cfs) 1=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) I Summary for Pond P: Pond I 124,121 sf, 35.04% Impervious, 15.57 cfs @ 11.99 hrs, Volume= 1.39 cfs @ 12.53 hrs, Volume= 1.39 cfs @ 12.53 hrs, Volume= Inflow Area = Inflow Outflow Primary Inflow Depth = 3.18" for 1 OO-year (6.00") event 32,943 cf 32,931 cf, Allen= 91%, Lag= 32.4 min 32,931 cf I Routing by Dyri-Storclnd method, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs Starting Elev= 906.00' Surf.Area= 4,911 sf Storage= 9,348 cf Peak Elev= 908.40' @ 12.53 hrs Surf.Area= 7,897 sf Storage= 24,648 cf (15,300 ct above start) I Plug-Flow detention time= 336.7 min calculated for 23,582 cf (72% of inflow) Center-at-Mass del. time= 149.5 min ( 976.1 - 826.6 ) Avail.Storaqe Storaqe Description 34,188 cf Custom Stage Data (Prismatic) Listed below (Recalc) Volume #1 Invert 901.00' I Elevation (feet) 901.00 903.00 905.00 906.00 908.00 909.00 909.50 Surf. Area (sq-ft) 573 1,359 2,401 4,911 7,352 8,720 9,442 Cum. Store (cubic-feet) o 1,932 5,692 9,348 21,611 29,647 34,188 Inc. Store (cubic-feet) o 1,932 3,760 3,656 12,263 8,036 4,541 I I Invert Outlet Devices 906.00' 6.0" Vert. OrificelGrate C= 0.600 904.25' 15.0" x21.0'long Culvert Ke= 0.500 Outlet Invert= 904.00' S= 0.0119 'I' Cc= 0.900 n= 0.012 908.50' 10.0' long x 5.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 DAD 0.60 0.80 1.00 1.20.1040 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.34 2.50 2.70 2.68 2.68 2.66 2.65 2.65 2.65 2.65 2.67 2.66 2.68 2.70 2.74 2.79 2.88 Primary OutFlow Max=1.39 cfs@ 12.53 hrs HW=908.40' TW=903A2' (Dynamic Tailwater) tt.culvert (passes 1.39 cfs of 11.09 cfs potential flow) 1=Orifice/Grate (Orifice Controls 1.39 cfs @ 7.06 fps) 3=Broad-Crested Rectangular Weir (Controls 0.00 cfs) Device #1 #2 #3 Routinq Device 2 Primary Primary I I I I I I I 081227 Proposed REV#2 (Pond on L282) Prepared by Plowe Engineering, Inc. HVdroCA[)@8.50 sin 001574 @2007 HvdroCAD Software Solutions LLC Type /I 24-hr 100-yr Back-ta-Back Rainfal/=6. 00" x 2 Printed 2/25/2009 Page 17 I Time span=0.00-200.00 hrs, dt=0.01 hrs, 20001 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method I Subcatchment 1: Direct to Lake Runoff Area=263,439 st .14.42% Impervious Runoff Depth=7.46" Fiow Length=625' Tc=18.3 min CN=66 Runoff=30.31 cts 163,867 ct Subcatchment 2: To Wetland Runoff Area=196,729st11.76% Impervious Runoff Depth=7.46" Flow Length=255' Tc=8.0 min CN=66 Runoff=30.94 cts 122,371 ct I Subcatchment 3: To Pond Runoff Area=124, 121 st 35.04% Impervious Runoff Depth=8.62" Tc=7.0 min CN=74 Runoff=21.66 cts 89,132 ct I Pond ExW: Exist Wetland Peak Elev=907.11: ~tor<lge=186,281 ct Inflow=37.04 cts 205,992 ct Outflow=0.91 cts 26,962 ct Pond P: Pond Peak Elev=909.01' Storage=29,770 ct Inflow=21.66 cts 89,132 ct . Outflow=11.20 cts 83,621 ct I Total Runoff Area = 584,289 sf Runoff Volume = 375,370 cf Average Runoff Depth = 7.71" 82.09% Pervious = 479,670 sf 17.91% Impervious = 104,619 sf I I I I I I I I I I I I I I 081227 Proposed REV#2 (Pond on L2B2) Prepared by Plowe Engineering, Inc. HvdroCAOO 8.50 sin 001574 @ 2007 HvdroCAD Software Solutions LLC Type 1/24-hr 100-yr Back-fo-Back Rainfal/=6.00" x 2 Printed 2/25/2009 Page 18 I Runoff I Summary for Subcatchment 1: Direct to Lake 30.31 cfs @ 36.09 hrs, Volume= 163,867 cf, Depth= 7.46" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs Type II 24-hr 100-yr Back-to-Back Rainfall=6.00" x 2 Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 16.9 300 0.0567 0.30 Sheet Flow, Grass: Short n= 0.150 P2= 2.70" 1.4 325 0.0635 3.78 Shallow Concentrated Flow, Grassed Waterway Kv= 15.0 fps 18.3 625 Total I Area (sf) 4,276 2,250 9,980 8,631 12,849 225,453 263,439 225,453 37,986 I I I I Runoff CN Description 98 Existing Roof 98 Existing Cone. Drive 98 Existing Bit. Drive 98 Proposed Drive 98 Proposed Roof 61 >75% Grass cover, Good. HSG B 66 Weighted Average Pervious Area Impervious Area Summary for Subcatchment 2: To Wetland 30.94 cfs @ 35.99 hrs, Volume= 122,371 cf, Depth= 7.46" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs Type II 24-hr 100-yr Back-to-Back Rainfall=6.00" x 2 Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.3 125 0.0800 0.28 Sheet Flow, Grass: Short n= 0.150 P2= 2.70" 0.7 130 0.0384 2.94 Shallow Concentrated Flow, Grassed Waterway Kv= 15.0 fps 8.0 255 Total I Area (sf) 7,500 4,500 6,500 4,640 8,872 164.717 196,729 173,589 23,140 I I I I Runoff CN Description 98 Existing Roof 98 Existing Cone. Drive 98 Existing Bit. Drive 98 Existing Bit. Trail 85 Existing Wetland 61 >75% Grass cover. Good, HSG B 66 Weighted Average Pervious Area Impervious Area Summary for Subcatchment 3: To Pond 21.66 cfs @ 35.98 hrs, Volume= 89,132 cf, Depth= 8.62" I Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs Type II 24-hr 100-yr Back-to-Back Rainfall=6.00" x 2 I Area (sf) 17,950 9,000 4,800 3,000 4,000 4,743 80,628 124,121 80,628 43,493 I I T c Length (min) (feet) 7.0 I Inflow Area = Inflow Outflow Primary I CN Description 98 Proposed Road 98 Proposed Roof 98 Proposed Drive 98 Existing Roof 98 Exisitng Bit. Trail 100 Pond NWL 61 >75% Grass cover, Good, HSG B 74 Weighted Average Pervious Area Impervious Area Slope Velocity Capacity Description (ft/ft) (ft/sec) (cfs) Direct Entry, Summary for Pond ExW: Exist Wetland 320,850 sf, 20.77% Impervious, 37.04 cfs @ 36.02 hrs, Volume= 0.91 cfs @ 42.61 hrs, Volume= 0.91 cfs @ 42.61 hrs, Volume= Inflow Depth = 7.70" for 100-yr Back-to-Back event 205,992 cf 26,962 cf, Allen= 98%, Lag= 395.3 min 26,962 cf I Type 1l24-hr 100-yr Back-ta-Back Rainfal/=6.00" x 2 Printed 2/25/2009 Pall'" 19 081227 Proposed REV#2 (Pond on L2B2) Prepared byPlowe Engineering, Inc. HvdroCAD@8.50 sin 001574 @2007 HvdroCAD Software Solutions LLC I Routing by Dyn-Stor-Ind method, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs Peak Elev= 907.11' @ 42.61 hrs Surf.Area= 65,583 sf Storage= 186,281 cf Plug-Flow detention time= 2,037.3 min calculated for 26,961 cf (13% of inflow) Center-of-Mass del. time= 1,013.9 min (2,759.1 -1,745.1) I Avail.StoraQe StoraQe Description 425,394 cf Custom Stage Data (Prismatic) Listed below (Recalc) Invert 899.40' Volume #1 I Cum. Store (cubic-feet) o 6,440 39,894 425,394 Inc. Store (cubic-feet) o 6,440 33,454 385,500 Surf.Area (sq-ftl o 4,954 28,500 100,000 Elevation (feet) 899.40 902.00 904.00 910.00 I Invert Outlet Devices 907.00' 10.0'long x 8.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.504.00 4.50 5.00 5.50 Coet. (English) 2.43 2.54 2.70 2.69 2.68 2.68 2.66 2.64 2;64 2.64 2.65 2.65 2.66 2.66 2.68 2.70 2.74 906.49' 2.00' x 3.00' Horiz. Orifice/Grate Limited to weir flow C= 0.600 RoutinQ Device 2 Device #1 I Primary #2 Primary OutFlow Max=0.9fcfs @ 42.61 hrs HW=907.11' (Free Discharge) LtOrifice/Grate (Passes 0.91 cfs of 16.04 cfs potential flow) 1=Broad-Crested Rectangular Weir (Weir Controls 0.91 cfs @ 0.81 fps) I Summary for Pond P: Pond I Inflow Depth = 8.62" for 100-yr Back-to-Back event 89,132 cf 83,621 cf, Allen= 48%, Lag= 5.6 min 83,621 cf 124,121 sf, 35.04% Impervious, 21.66 cfs @ 35.98 hrs, Volume= 11.20 cfs@ 36.07 hrs, Volume= 11.20 cfs@ 36.07 hrs, Volume= Inflow Area = Inflow Outflow Primary I Routing by Dyn-Stor-Ind method, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs Starting Elev= 906.00' Surf.Area= 4,911 sf Storage= 9,348 cf Peak Elev= 909.01' @ 36.07 hrs Surf.Area= 8,740 sf Storage= 29,770 cf (20,422 cf above start) Plug-Flow detention time= 359.2 min calculated for 74,273 cf (83% of inflow) Center-of-Mass del. time= 80.2 min ( 1,752.8 - 1,672.6) I Avail.StoraQe StoraQe Description 34,188 cf Custom Stage Data (Prismatic) Listed below (Recalc) Invert 901.00' Volume #1 I Inc. Store (cubic-feet) o 1,932 3,760 3,656 12,263 8,036 4,541 Cum. Store (cubic-feet) o 1,932 5,692 9,348 21,611 29,647 34,188 Surf.Area (sq-ftl 573 1,359 2,401 4,911 7,352 8,720 9,442 Elevation (feet) 901.00 903.00 905.00 906.00 908.00 909.00 909.50 I I Outlet Devices 6.0" Vert. Orifice/Grate C= 0.600 15.0" x 21.0' long Culvert Ke= 0.500 Outlet Invert= 904.00' S= 0.0119 'f' Cc= 0.900 n= 0.012 10.0' long x 5.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coet. (English) 2.34 2.50 2.70 2.68 2.68 2.66 2.65 2.65 2.65 2.65 2.67 2.66 2.68 2.70 2.74 2.79 2.88 Primary OutFlow Max=11.18 cfs @ 36.07 hrs HW=909.01' TW=906.29' (Dynamic Tailwater) tt.culvert (Passes 1.56 cfs of 9.75 cfs potential flow) 1=Orifice/Grate (Orifice Controls 1.56 cfs @ 7.94 fps) 3=Broad-Crested Rectangular Weir (Weir Controls 9.62 cfs @ 1.87 fps) RoutinQ Device 2 Primary Primary Invert 906.00' 904.25' 908.50' Device #1 #2 #3 I I I I I I