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Drainage Calculations 8-29-06
ABRA AUTOBODY 60 LAKE DRIVE EAST CITY OF CHANHASSEN, MN DRAINAGE CALCULATIONS PREPARED BY: ALLIANT ENGINEERING INC. FOR: ABRA AUTOBODY AUGUST 29, 2006 ALLIANT PROJECT NO. 060027 Existing Drainage Conditions The project site is currently operated as an automotive maintenance business consisting of a single story structure, paved surfaces and green space. The majority of the site runoff from the parking lot currently flows overland to the north entering an existing catch basin which discharges through a 4" PVC storm line to a trunk 33" storm sewer flowing easterly along State Highway No.5. An additional portion of the site runoff flows directly overland to an existing 15" apron in the Hwy. 5 south ditch that also discharges to the existing 33" trunk storm sewer. The south portion of the parking lot drains to a catch basin that discharges to a 12" RCP storm sewer line in the street and ultimately to the existing storm pond north of Lake Drive East. Smaller areas of the site drain overland to the existing street to the southeast, and the wetland in the southwest corner of the property. The overland flow to the street also ultimately discharges to the pond on the north side of Lake Drive East. An existing drainage area map is included herein. The property currently consists of 0.72 acres (38%) impervious surfaces (roofs and paved surfaces) and 1.17 acres (62%) green space. The wetland area is included in the green space area for purposes of the above calculation. Proposed Conditions The project consists of constructing a single story automotive repair and maintenance business and adjacent parking lot. The existing building will remain and will be connected to the proposed building addition. The entire parking lot will be reconstructed. In general, existing drainage patterns are being maintained under the proposed conditions. Runoff from the site for existing and proposed conditions was analyzed for the 2-year, 10-year and 1 DO-year events utilizing Hydrocad design software. Hydrocad input parameters and results are included herein. Runoff calculations were performed for the property as a whole, including those areas where improvements are not proposed. The north portion of the new parking lot will drain to a proposed catch basin located along the east side ofthe parking lot. The catch basin outlet pipe is sized as a 6" diameter PVC pipe to restrict outflow from the site and promote minimal ponding in the parking areas under large rainfall events prior to overtopping the back of curb and flowing onto adjacent property. The 6" pipe will discharge to the existing structure located on the north end ofthe existing parking lot. The tributary area to the pipe discharging to the 33" trunk line has been decreased from the existing condition. Runoff from the roof of the new building addition will discharge at grade and will be conveyed along the gutter line and ultimately discharge to the proposed on site treatment pond. The south segment of the parking lot will drain to two proposed curb cuts discharging to the on site treatment pond. The on site pond outlets to the catch basins in the adjacent street and ultimately into the pond located on the car wash site to the east. The pond characteristics are described below. Smaller areas of the southerly portion of the site will continue to flow overland to the street to the southeast and to the wetland in the southwest comer. The street runoff discharges to existing catch basins located along the entrance road and ultimately drains to the pond north of Lake Drive East. The proposed improvements result in 1.15 acres (61 %) impervious surfaces and 0.74 acres (39%) green space within the property. The existing wetland is included in the green space area. Comparison of Existing and Proposed Conditions The proposed project will result in an increase of 0.43 acres of impervious surface while decreasing the nmoffrates from the site to the Hwy. 5 ROWand the existing pond north of Lake Drive East. On the north end of the project site, the proposed 6" PVC outlet from the catch basin and the runoff entering the 15" apron in the Hwy. 5 ditch discharge to the trunk 33" storm pipe in the Hwy. 5 ROW. The discharge to the pipe is decreased slightly from the existing condition after the revised grading and restriction of the 6" outlet pipe. The proposed 100-year runoff rate to the 33" tmnk storm sewer would be decreased by 0.21 cfs. On the south end of the project site, a pond is proposed to treat runoff and provide live storage volume for rate control. The proximity to the existing wetland will not allow adequate room to provide a 4' deep wet pond. The westerly portion of the pond will be 3.5' deep from NWL to bottom and the east side will be 2.5' deep. Per an 8/29/06 conversation with City engineering staff, the reduced pond depth will be acceptable if other pond design parameters are met. The City is requiring dead storage be provided to treat mnoff from the increase in impervious surface. The permanent pool provided substantially exceeds that requirement due to over excavation to provide rate control volume. The pond outlet structure will be located at the south end of the pond away from the inlet flumes. The outlet structure will consist of a submerged pipe inlet to provide skimming, a concrete manhole with weir wall and a 6" orifice outlet. An outlet pipe will be routed to tie into the existing storm sewer in the adjacent street. The outlet is set at the observed elevation of the adjacent wetland. An equalizer pipe is proposed to be constructed between the pond and the wetland at an elevation above the pond normal water elevation to charge the wetland in larger events and to achieve additional rate control volume within the wetland during large storm events. Smaller storm events will be contained in the treatment pond and released without discharge to the wetland. The sides and bottom of the pond will be planted with seed mix to allow for plant growth types adapting to the varying degrees of wetness. Site soils are anticipated to be mostly loams per the Carver County Soils Survey information. The proposed runoffto the wetland and offsite overland to the street to the southeast will be slightly reduced by the proposed improvements. Existing and proposed peak runoff rates and volumes are depicted in table 1 for comparison. Table 1: Peak Runoff Rates and Volumes Peak Runoff [cfs] Runoff Volume [ac-ft] DRAINAGE AREA 2-yr 10-yr 100-yr 2-yr 10-yr 100-yr 0-1 0.23 0.82 1.78 0.014 0.040 0.084 0-2 0.07 0.37 0.89 0.006 0.019 0.044 E-1 1.87 3.10 4.66 0.096 0.164 2.530 Cl E-2 0.68 1.17 1.80 0.029 0.053 0.084 s::: .. W-1 0.83 1.55 2.50 0.039 0.075 0.124 en 'x TOTAL 2.53 4.62 7.64 0.184 0.351 0.588 w MnDOT 1.08 1.69* 2.68 0.110 0.204 0.337 CAR WASH POND 0.70 1.46 2.57 0.035 0.072 0.127 WETLAND 0.83 1.55 2.50 0.039 0.075 0.124 0-1 0.04 0.22 0.55 0.004 0.015 0.034 0-2 0.03 0.13 0.31 0.002 0.007 0.015 P-1 1.08 1.66 2.41 0.050 0.079 0.117 "C P-2 3.44 5.32 7.71 0.183 0.291 0.430 ell en P-3 0.64 1.14 1.79 0.028 0.051 0.082 0 Co W-1 0.56 0.98 1.51 0.026 0.046 0.073 0 ... 0- TOTAL 2.04 3.31 4.95 0.292 0.488 0.750 MnDOT 1.07 1.71 * 2.47 0.054 0.094 0.150 CAR WASH POND 0.56 0.77 1.07 0.213 0.348 0.527 WETLAND 0.56 0.98 1.51 0.026 0.046 0.073 Note: * - negligible rate increase during 1 O-year event. 2-year and 100-year events are decreased. z:::~- <::>~ // ))---))-;:::::::~"--~/ - __~2_~:b'--' -- -,--,-' --..--- ~~ ,,:--- / -~ -- ,,' -,----- -, -// // .- -,.-' . . ------ , ////// ,A'/ -'? 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NO: ABR:XISTING DRAINAGE AUTO BODY 40 LAKE DRIVE ~:l.ASS CHANHASSEN,UN ~ AUTO BODY & GlASS ~~a~~RnN rn,f.T n<<s ~:L'f UCE:~ti ~~ SU~Sl:SAN~AREO BY "'NT :::':' STA" rY :':,~~.:'"'N'ER .:~ ';: SlCNE:O: <E-1) ~Ah North Sub 4" outlet <E-Z) ~M South Sub 48"CB <0-2) ~~ Offsite SE Car Wash Pond ~UbC1 IR~~~~1 A ~ <0-1) Offs te N ~8] <W-1) Wetland ~ ~ Total Drainage Diagram for existing Prepared by Alliant Engineering, Inc. 8/30/2006 HydroCAD@7.10 sin 001427 @2005HydroCAD Software Solutions LLC existing Prepared by Alliant Engineering, Inc. HydroCAD@ 7.10 sIn 001427 @ 2005 HydroCAD Software Solutions LLC Type /I 24-hr 2-yr Rainfal/=2.70" Page 2 8/30/2006 Time span=0.00-25.00 hrs, dt=0.01 hrs, 2501 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+ Trans method - Pond routing by Stor-Ind method Subcatchment E-1: North Sub Runoff Area=26,625 sf Runoff Depth=1.88" Flow Length=139' Tc=7.5 min CN=92 Runoff=1.87 cfs 0.096 af Subcatchment E-2: South Sub Runoff Area=9,425 sf Runoff Depth=1.63" Flow Length=75' Tc=3.5 min CN=89 Runoff=0.68 cfs 0.029 af Subcatchment 0-1: Offsite N Runoff Area=19,308 sf Runoff Depth=0.38" Flow Length=141' Tc=6.4 min CN=65 Runoff=0.23 cfs 0.014 af Subcatchment 0-2: Offsite SE Runoff Area=11 ,737 sf Runoff Depth=0.26" Flow Length=88' Tc=6.9 min CN=61 Runoff=0.07 cfs 0.006 af Subcatchment W-1: Wetland Runoff Area=15,386 sf Runoff Depth=1.34" Flow Length=60' Tc=6.4 min CN=85 Runoff=0.83 cfs 0.039 af Pond E1: 4" outlet Peak Elev=934.54' Storage=569 cf Inflow=1.87 cfs 0.096 af 4.0" x 8.0' Culvert Outflow=0.85 cfs 0.096 af Pond E2: 48" CB Peak Elev=934.03' Storage=5 cf Inflow=0.68 cfs 0.029 af 12.0" x 91.0' Culvert Outflow=0.68 cfs 0.029 af Link 1 L: MnDOT Ditch Inflow=1.08 cfs 0.110 af Primary=1.08 cfs 0.110 af Link 2L: Car Wash Pond Inflow=0.70 cfs 0.035 af Primary=0.70 cfs 0.035 af Link 3L: Total Inflow=2.53 cfs 0.184 af Primary=2.53 cfs 0.184 af Total Runoff Area = 1.894 ac Runoff Volume = 0.184 af Average Runoff Depth = 1.17" existing Prepared by Alliant Engineering, Inc. HydroCAD@ 7.10 sIn 001427 @ 2005 HydroCAD Software Solutions LLC Type II 24-hr 2-yr Rainfal/=2.70" Page 3 8/30/2006 Runoff = Subcatchment E-1: North Sub 1.87 cfs @ 11.99 hrs, Volume= 0.096 af, Depth= 1.88" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-25.00 hrs, dt= 0.01 hrs Type II 24-hr 2-yr Rainfall=2.70" Area (sf) 22,245 4,380 26,625 CN Description 98 Paved parking & roofs 61 >75% Grass cover, Good, HSG B 92 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (fUft) (fUsec) (cfs) 7.1 70 0.0270 0.2 Sheet Flow, Grass: Short n= 0.150 P2= 2.70" 0.4 69 0.0220 3.0 Shallow Concentrated Flow, Paved Kv= 20.3 fps 7.5 139 Total Runoff = Subcatchment E-2: South Sub 0.68 cfs @ 11.94 hrs, Volume= 0.029 af, Depth= 1.63" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-25.00 hrs, dt= 0.01 hrs Type II 24-hr 2-yr Rainfall=2.70" Area (sf) 7,200 2,225 9,425 CN Description 98 Paved parking & roofs 61 >75% Grass cover, Good, HSG B 89 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (fUft) (fUsec) (cfs) 3.3 36 0.0495 0.2 Sheet Flow, Grass: Short n= 0.150 P2= 2.70" 0.2 39 0.0267 3.3 Shallow Concentrated Flow, Paved Kv= 20.3 fps 3.5 75 Total Runoff = Subcatchment 0-1: Offsite N 0.23 cfs @ 12.00 hrs, Volume= 0.014 af, Depth= 0.38" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-25.00 hrs, dt= 0.01 hrs Type II 24-hr 2-yr Rainfall=2.70" existing Prepared by Alliant Engineering, Inc. HydroCAO@7.10 sin 001427 @2005 HydroCAO Software Solutions LLC Type II 24-hr 2-yr Rainfal/=2.70" Page 4 8/30/2006 Area (sf) 17,296 2,012 19,308 CN Description 61 >75% Grass cover, Good, HSG B 98 Paved parkinq & roofs 65 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (fUft) (ftlsec) (cfs) 6.4 141 0.0250 0.4 Lag/eN Method, Runoff = Subcatchment 0-2: Offsite SE 0.07 cfs @ 12.02 hrs, Volume= 0.006 af, Depth= 0.26" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-25.00 hrs, dt= 0.01 hrs Type II 24-hr 2-yr Rainfall=2.70" Area (sf) 11,737 CN Description 61 >75% Grass cover, Good, HSG B Tc Length Slope Velocity Capacity Description (min) (feet) (ftlft) (fUsec) (cfs) 6.9 88 0.0462 0.2 Sheet Flow, Grass: Short n= 0.150 P2= 2.70" Runoff = Subcatchment W-1 : Wetland 0.83 cfs @ 11.98 hrs, Volume= 0.039 af, Depth= 1.34" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-25.00 hrs, dt= 0.01 hrs Type II 24-hr 2-yr Rainfall=2.70" Area (sf) 5,781 9,605 15,386 CN Description 61 >75% Grass cover, Good, HSG B 100 Wetland Edqe 85 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ftlft) (ftlsec) (cfs) 6.4 60 0.0655 0.2 Sheet Flow, Grass: Dense n= 0.240 P2= 2.70" Inflow Area = Inflow = Outflow = Primary = Pond E1: 4" outlet 0.611 ac, Inflow Depth = 1.88" 1.87 cfs @ 11.99 hrs, Volume= 0.85 cfs @ 12.09 hrs, Volume= 0.85 cfs @ 12.09 hrs, Volume= for 2-yr event 0.096 af 0.096 af, Atten= 54%, Lag= 6.4 min 0.096 af Routing by Stor-Ind method, Time Span= 0.00-25.00 hrs, dt= 0.01 hrs existing Prepared by Alliant Engineering, Inc. HydroCAD@ 7.10 sIn 001427 @ 2005 HydroCAD Software Solutions LLC Type /I 24-hr 2-yr Rainfal/=2.70" Page 5 8/30/2006 Peak Elev= 934.54' @ 12.09 hrs Surf.Area= 1,785 sf Storage= 569 cf Plug-Flow detention time= 2.7 min calculated for 0.096 af (100% of inflow) Center-of-Mass del. time= 2.7 min ( 805.0 - 802.3 ) Volume #1 Elevation (feet) 930.24 933.00 934.00 934.10 934.20 934.30 934.40 934.50 934.60 934.70 934.80 934.90 935.00 935.50 Device #1 Invert 930.24' Avail.Storage Storage Description 3,646 cf Custom Stage Data (Prismatic) Listed below (Recalc) Surf.Area (sq-ft) 6 6 85 399 712 1,026 1,339 1,653 1,966 2,280 2,593 2,907 3,220 4,505 Inc.Store ( cubic-feet) o 17 46 24 56 87 118 150 181 212 244 275 306 1,931 Cum.Store ( cubic-feet) o 17 62 86 142 229 347 497 678 890 1,133 1 ,408 1,715 3,646 Routing Primary Invert Outlet Devices 930.24' 4.0" x 8.0' long Culvert RCP, sq. cut end projecting, Ke= 0.500 Outlet Invert= 929.97' S= 0.0337 'I' Cc= 0.900 n= 0.010 PVC, smooth interior Primary OutFlow Max=0.85 cfs @ 12.09 hrs HW=934.54' (Free Discharge) "t..-1=Culvert (Inlet Controls 0.85 cfs @ 9.8 fps) Inflow Area = Inflow = Outflow = Primary = Pond E2: 48" CB 0.216 ac, Inflow Depth = 1.63" 0.68 cfs @ 11.94 hrs, Volume= 0.68 cfs @ 11.94 hrs, Volume= 0.68 cfs @ 11.94 hrs, Volume= for 2-yr event 0.029 af 0.029 af, Atten= 0%, Lag= 0.1 min 0.029 af Routing by Stor-Ind method, Time Span= 0.00-25.00 hrs, dt= 0.01 hrs Peak Elev= 934.03' @ 11.94 hrs Surf.Area= 13 sf Storage= 5 cf Plug-Flow detention time= 0.5 min calculated for 0.029 af (100% of inflow) Center-of-Mass del. time= 0.5 min (813.2 - 812.6 ) Volume #1 Invert 933.61' Avail. Storage Storage Description 701 cf Custom Stage Data (Prismatic) Listed below (Recalc) existing Prepared by Alliant Engineering, Inc. HydroCAD@ 7.10 sin 001427 @ 2005 HydroCAD Software Solutions LLC Type /I 24-hr 2-yr Rainfal/=2.70" Page 6 8/30/2006 Elevation (feet) 933.61 935.90 936.00 936.10 936.20 936.30 936.40 936.50 936.60 936.70 936.80 936.90 937.00 Device Routin~ #1 Primary Surf.Area (sq-ft) 13 13 40 93 162 251 359 489 673 915 1,193 1,514 2,040 Inc.Store ( cubic-feet) o 30 3 7 13 21 31 42 58 79 105 135 178 Cum.Store ( cubic-feet) o 30 32 39 52 72 103 145 203 283 388 524 701 Invert Outlet Devices 933.61' 12.0" x 91.0' long Culvert RCP, sq.cut end projecting, Ke= 0.500 Outlet Invert= 931.88' S= 0.0190 'J' Cc= 0.900 n= 0.013 Concrete sewer w/manholes & inlets Primary OutFlow Max=0.67 cfs @ 11.94 hrs HW=934.02' (Free Discharge) L1=Culvert (Inlet Controls 0.67 cfs @ 2.2 fps) Inflow Area = Inflow = Primary = Link 1 L: MnDOT Ditch 1.054 ac, Inflow Depth = 1.25" for 2-yr event 1.08 cfs @ 12.01 hrs, Volume= 0.110 af 1.08 cfs @ 12.01 hrs, Volume= 0.110 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-25.00 hrs, dt= 0.01 hrs I nflow Area = Inflow = Primary = Link 2L: Car Wash Pond 0.486 ac, Inflow Depth = 0.87" for 2-yr event 0.70 cfs @ 11.95 hrs, Volume= 0.035 af 0.70 cfs @ 11.95 hrs, Volume= 0.035 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-25.00 hrs, dt= 0.01 hrs Inflow Area = Inflow = Primary = Link 3L: Total 1.894 ac, Inflow Depth = 1.17" for 2-yr event 2.53 cfs @ 11.97 hrs, Volume= 0.184 af 2.53cfs@ 11.97hrs, Volume= 0.184af, Atten=O%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-25.00 hrs, dt= 0.01 hrs existing Prepared by Alliant Engineering, Inc. HydroCAD@ 7.10 sin 001427 @ 2005 HydroCAD Software Solutions LLC Type /I 24-hr 10-yr Rainfal/=4.10" Page 7 8/30/2006 Time span=0.00-25.00 hrs, dt=0.01 hrs, 2501 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-lnd+Trans method - Pond routing by Stor-Ind method Subcatchment E-1: North Sub Runoff Area=26,625 sf Runoff Depth=3.21" Flow Length=139' Tc=7.5 min CN=92 Runoff=3.10 cfs 0.164 af Subcatchment E-2: South Sub Runoff Area=9,425 sf Runoff Depth=2.92" Flow Length=75' Tc=3.5 min CN=89 Runoff=1.17 cfs 0.053 af Subcatchment 0-1: Offsite N Runoff Area=19,308 sf Runoff Depth=1.09" Flow Length=141' Tc=6.4 min CN=65 Runoff=0.82 cfs 0.040 af Subcatchment 0-2: Offsite SE Runoff Area=11, 737 sf Runoff Depth=0.86" Flow Length=88' Tc=6.9 min CN=61 Runoff=0.37 cfs 0.019 af Subcatchment W-1: Wetland Runoff Area=15,386 sf Runoff Depth=2.55" Flow Length=60' Tc=6.4 min CN=85 Runoff=1.55 cfs 0.075 af Pond E1: 4" outlet Peak Elev=934.95' Storage=1,554 cf Inflow=3.10 cfs 0.164 af 4.0" x 8.0' Culvert Outflow=0.90 cfs 0.164 af Pond E2: 48" CB Peak Elev=934.17' Storage=7 cf Inflow=1.17 cfs 0.053 af 12.0" x 91.0' Culvert Outflow=1.17 cfs 0.053 af Link 1L: MnDOT Ditch Inflow=1.69 cfs 0.204 af Primary=1.69 cfs 0.204 af Link 2L: Car Wash Pond Inflow=1.46 cfs 0.072 af Primary=1.46 cfs 0.072 af Link 3L: Total Inflow=4.62 cfs 0.351 af Primary=4.62 cfs 0.351 af Total Runoff Area = 1.894 ac Runoff Volume = 0.351 af Average Runoff Depth = 2.22" existing Prepared by Alliant Engineering, Inc. HydroCAD@ 7.10 sin 001427 @2005 HydroCAD Software Solutions LLC Type 1/24-hr 10-yr Rainfal/=4.10" Page 8 8/30/2006 Runoff = Subcatchment E-1: North Sub 3.10 cfs @ 11.99 hrs, Volume= 0.164 af, Depth= 3.21" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-25.00 hrs, dt= 0.01 hrs Type II 24-hr 10-yr Rainfall=4.10" Area (sf) 22,245 4,380 26,625 CN Description 98 Paved parking & roofs 61 >75% Grass cover, Good, HSG B 92 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ftIft) (ftlsec) (ds) 7.1 70 0.0270 0.2 Sheet Flow, Grass: Short n= 0.150 P2= 2.70" 0.4 69 0.0220 3.0 Shallow Concentrated Flow, Paved Kv= 20.3 fps 7.5 139 Total Runoff = Subcatchment E-2: South Sub 1.17cfs@ 11.94hrs, Volume= 0.053 af, Depth= 2.92" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-25.00 hrs, dt= 0.01 hrs Type II 24-hr 10-yr Rainfall=4.10" Area (sf) 7,200 2,225 9,425 CN Description 98 Paved parking & roofs 61 >75% Grass cover, Good, HSG B 89 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ftIft) (ftIsec) (cfs) 3.3 36 0.0495 0.2 Sheet Flow, Grass: Short n= 0.150 P2= 2.70" 0.2 39 0.0267 3.3 Shallow Concentrated Flow, Paved Kv= 20.3 fps 3.5 75 Total Runoff Subcatchment 0-1: Offsite N = 0.82 cfs @ 11.99 hrs, Volume= 0.040 af, Depth= 1.09" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-25.00 hrs, dt= 0.01 hrs Type II 24-hr 10-yr Rainfall=4.10" existing Prepared by Alliant Engineering, Inc. HydroCAD@7.10 sIn 001427 @2005 HydroCAD Software Solutions LLC Type /I 24-hr 10-yr Rainfal/=4.10" Page 9 8/30/2006 Area (sf) 17,296 2,012 19,308 CN Description 61 >75% Grass cover, Good, HSG B 98 Paved parkin~ & roofs 65 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.4 141 0.0250 0.4 Lag/eN Method, Runoff = Subcatchment 0-2: Offsite SE 0.37 cfs @ 12.00 hrs, Volume= 0.019 af, Depth= 0.86" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-25.00 hrs, dt= 0.01 hrs Type II 24-hr 10-yr Rainfall=4.10" Area (sf) 11,737 CN Description 61 >75% Grass cover, Good, HSG B Tc Length Slope Velocity Capacity Description (min) (feet) (fUft) (ft/sec) (cfs) 6.9 88 0.0462 0.2 Sheet Flow, Grass: Short n= 0.150 P2= 2.70" Runoff = Subcatchment W-1 : Wetland 1.55 cfs @ 11.98 hrs, Volume= 0.075 af, Depth= 2.55" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-25.00 hrs, dt= 0.01 hrs Type II 24-hr 10-yr Rainfall=4.10" Area (sf) 5,781 9,605 15,386 CN Description 61 >75% Grass cover, Good, HSG B 100 Wetland Ed~e 85 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (fUft) (ft/sec) (cfs) 6.4 60 0.0655 0.2 Sheet Flow, Grass: Dense n= 0.240 P2= 2.70" Inflow Area = Inflow = Outflow = Primary = Pond E1: 4" outlet 0.611 ac, Inflow Depth = 3.21" 3.10 cfs @ 11.99 hrs, Volume= 0.90 cfs @ 12.13 hrs, Volume= 0.90 cfs @ 12.13 hrs, Volume= for 10-yr event 0.164 af 0.164 af, Atten= 71 %, Lag= 8.8 min 0.164af Routing by Stor-Ind method, Time Span= 0.00-25.00 hrs, dt= 0.01 hrs existing Prepared by Alliant Engineering, Inc. HydroCAD@ 7.10 sIn 001427 @ 2005 HydroCAD Software Solutions LLC Type 1/24-hr 10-yr Rainfal/=4.10" Page 1 0 8/30/2006 Peak Elev= 934.95' @ 12.13 hrs Surf.Area= 3,060 sf Storage= 1,554 cf Plug-Flow detention time= 8.1 min calculated for 0.164 af (100% of inflow) Center-of-Mass det. time= 8.1 min ( 795.4 - 787.3 ) Volume #1 Elevation (feet) 930.24 933.00 934.00 934.10 934.20 934.30 934.40 934.50 934.60 934.70 934.80 934.90 935.00 935.50 Device #1 Invert 930.24' Avail. Storage Storage Description 3,646 cf Custom Stage Data (Prismatic) Listed below (Recalc) Surf.Area (sq-ft) 6 6 85 399 712 1,026 1,339 1,653 1,966 2,280 2,593 2,907 3,220 4,505 Inc.Store (cubic-feet) o 17 46 24 56 87 118 150 181 212 244 275 306 1,931 Cum.Store ( cubic-feet) o 17 62 86 142 229 347 497 678 890 1,133 1 ,408 1,715 3,646 Routing Primary Invert Outlet Devices 930.24' 4.0" x 8.0' long Culvert RCP, sq.cut end projecting, Ke= 0.500 Outlet Invert= 929.97' S= 0.0337 'I' Cc= 0.900 n= 0.010 PVC, smooth interior Primary OutFlow Max=0.90 cfs @ 12.13 hrs HW=934.95' (Free Discharge) L1=Culvert (Inlet Controls 0.90 cfs @ 10.3 fps) Inflow Area = Inflow = Outflow = Primary = Pond E2: 48" CB 0.216 ac, Inflow Depth = 2.92" 1.17cfs@ 11.94hrs, Volume= 1.17 cfs @ 11.94 hrs, Volume= 1.17 cfs @ 11.94 hrs, Volume= for 10-yr event 0.053 af 0.053 af, Atten= 0%, Lag= 0.1 min 0.053 af Routing by Stor-Ind method, Time Span= 0.00-25.00 hrs, dt= 0.01 hrs Peak Elev= 934.17' @ 11.94 hrs Surf.Area= 13 sf Storage= 7 cf Plug-Flow detention time= 0.4 min calculated for 0.053 af (100% of inflow) Center-of-Mass det. time= 0.4 min ( 796.5 - 796.1 ) Volume #1 Invert 933.61' Avail.Storage Storage Description 701 cf Custom Stage Data (Prismatic) Listed below (Recalc) existing Prepared by Alliant Engineering, Inc. HydroCAD@ 7.10 sIn 001427 @ 2005 HydroCAD Software Solutions LLC Type /I 24-hr 10-yr Rainfal/=4.10" Page 11 8/30/2006 Elevation (feet) 933.61 935.90 936.00 936.10 936.20 936.30 936.40 936.50 936.60 936.70 936.80 936.90 937.00 Device #1 Routin~ Primary Surf.Area ( sq-ft) 13 13 40 93 162 251 359 489 673 915 1,193 1,514 2,040 Inc.Store ( cubic-feet) o 30 3 7 13 21 31 42 58 79 105 135 178 Cum.Store ( cubic-feet) o 30 32 39 52 72 103 145 203 283 388 524 701 Invert Outlet Devices 933.61' 12.0" x 91.0' long Culvert RCP, sq.cut end projecting, Ke= 0.500 Outlet Invert= 931.88' S= 0.0190 'J' Cc= 0.900 n= 0.013 Concrete sewer w/manholes & inlets Primary OutFlow Max=1.17 cfs @ 11.94 hrs HW=934.17' (Free Discharge) L1=Culvert (Inlet Controls 1.17 cfs @ 2.6 fps) Inflow Area = Inflow = Primary = Link 1 L: MnDOT Ditch 1.054 ac, Inflow Depth = 2.32" for 10-yr event 1.69 cfs @ 11.99 hrs, Volume= 0.204 af 1.69 cfs @ 11.99 hrs, Volume= 0.204 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-25.00 hrs, dt= 0.01 hrs I nflow Area = Inflow = Primary = Link 2L: Car Wash Pond 0.486 ac, Inflow Depth = 1.78" for 10-yr event 1.46 cfs @ 11.95 hrs, Volume= 0.072 af 1.46 cfs @ 11.95 hrs, Volume= 0.072 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-25.00 hrs, dt= 0.01 hrs I nflow Area = Inflow = Primary = Link 3L: Total 1.894 ac, Inflow Depth = 2.22" for 10-yr event 4.62 cfs @ 11.97 hrs, Volume= 0.351 af 4.62 cfs @ 11.97 hrs, Volume= 0.351 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-25.00 hrs, dt= 0.01 hrs existing Prepared by Alliant Engineering, Inc. HydroCAD@ 7.10 sIn 001427 @ 2005 HydroCAD Software Solutions LLC Type /I 24-hr 100-yr Rainfal/=5.90" Page 12 8/30/2006 Time span=0.00-25.00 hrs, dt=0.01 hrs, 2501 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+ Trans method - Pond routing by Stor-Ind method Subcatchment E-1: North Sub Runoff Area=26,625 sf Runoff Depth=4.97" Flow Length=139' Tc=7.5 min CN=92 Runoff=4.66 cfs 0.253 af Subcatchment E-2: South Sub Runoff Area=9,425 sf Runoff Depth=4.64" Flow Length=75' Tc=3.5 min CN=89 Runoff=1.80 cfs 0.084 af Subcatchment 0-1: Offsite N Runoff Area=19,308 sf Runoff Depth=2.28" Flow Length=141' Tc=6.4 min CN=65 Runoff=1.78 cfs 0.084 af Subcatchment 0-2: Offsite SE Runoff Area=11 ,737 sf Runoff Depth=1.94" Flow Length=88' Tc=6.9 min CN=61 Runoff=0.89 cfs 0.044 af Subcatchment W-1: Wetland Runoff Area=15,386 sf Runoff Depth=4.21" Flow Length=60' Tc=6.4 min CN=85 Runoff=2.50 cfs 0.124 af Pond E1: 4" outlet Peak Elev=935.35' Storage=3,013 cf Inflow=4.66 cfs 0.253 af 4.0" x 8.0' Culvert Outflow=0.93 cfs 0.253 af Pond E2: 48" CB Peak Elev=934.34' Storage=10 cf Inflow=1.80 cfs 0.084 af 12.0" x 91.0' Culvert Outflow=1.80 cfs 0.084 af Link 1 L: MnDOT Ditch Inflow=2.68 cfs 0.337 af Primary=2.68 cfs 0.337 af Link 2L: Car Wash Pond Inflow=2.57 cfs 0.127 af Primary=2.57 cfs 0.127 af Link 3L: Total Inflow=7.64 cfs 0.588 af Primary=7.64 cfs 0.588 af Total Runoff Area = 1.894 ac Runoff Volume = 0.588 af Average Runoff Depth = 3.73" existing Prepared by Alliant Engineering, Inc. HydroCAO@ 7.10 sIn 001427 @ 2005 HydroCAO Software Solutions LLC Type /I 24-hr 100-yr Rainfal/=5.90" Page 13 8/30/2006 Runoff = Subcatchment E-1: North Sub 4.66 cfs @ 11.98 hrs, Volume= 0.253 af, Depth= 4.97" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-25.00 hrs, dt= 0.01 hrs Type II 24-hr 100-yr Rainfall=5.90" Area (sf) 22,245 4,380 26,625 CN Description 98 Paved parking & roofs 61 >75% Grass cover, Good, HSG B 92 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.1 70 0.0270 0.2 Sheet Flow, Grass: Short n= 0.150 P2= 2.70" 0.4 69 0.0220 3.0 Shallow Concentrated Flow, Paved Kv= 20.3 fps 7.5 139 Total Runoff = Subcatchment E-2: South Sub 1.80 cfs @ 11.94 hrs, Volume= 0.084 af, Depth= 4.64" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-25.00 hrs, dt= 0.01 hrs Type II 24-hr 100-yr Rainfall=5.90" Area (sf) 7,200 2,225 9,425 CN Description 98 Paved parking & roofs 61 >75% Grass cover, Good, HSG B 89 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ftIft) (fUsee) (cfs) 3.3 36 0.0495 0.2 Sheet Flow, Grass: Short n= 0.150 P2= 2.70" 0.2 39 0.0267 3.3 Shallow Concentrated Flow, Paved Kv= 20.3 fps 3.5 75 Total Runoff = Subcatchment 0-1: Offsite N 1.78 cfs @ 11.98 hrs, Volume= 0.084 af, Depth= 2.28" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-25.00 hrs, dt= 0.01 hrs Type II 24-hr 100-yr Rainfall=5.90" existing Prepared by Alliant Engineering, Inc. HydroCAO@7.10 sin 001427 @2005 HydroCAO Software Solutions LLC Type 1/24-hr 100-yr Rainfal/=5.90" Page 14 8/30/2006 Area (sf) 17,296 2,012 19,308 CN Description 61 >75% Grass cover, Good, HSG B 98 Paved parkinq & roofs 65 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ftlft) (ftlsec) (cfs) 6.4 141 0.0250 0.4 Lag/eN Method, Runoff = Subcatchment 0-2: Offsite SE 0.89 cfs @ 11.99 hrs, Volume= 0.044 af, Depth= 1.94" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-25.00 hrs, dt= 0.01 hrs Type II 24-hr 100-yr Rainfall=5.90" Area (sf) 11 ,737 CN Description 61 > 75% Grass cover, Good, HSG B Tc Length Slope Velocity Capacity Description (min) (feet) (ftlft) (ftlsec) (cfs) 6.9 88 0.0462 0.2 Sheet Flow, Grass: Short n= 0.150 P2= 2.70" Runoff = Subcatchment W-1 : Wetland 2.50 cfs @ 11.97 hrs, Volume= 0.124 af, Depth= 4.21" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-25.00 hrs, dt= 0.01 hrs Type II 24-hr 100-yr Rainfall=5.90" Area (sf) 5,781 9,605 15,386 CN Description 61 >75% Grass cover, Good, HSG B 100 Wetland Edqe 85 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ftlft) (ftlsec) (cfs) 6.4 60 0.0655 0.2 Sheet Flow, Grass: Dense n= 0.240 P2= 2.70" Inflow Area = Inflow = Outflow = Primary = Pond E1: 4" outlet 0.611 ac, Inflow Depth = 4.97" 4.66 cfs @ 11.98 hrs, Volume= 0.93 cfs @ 12.17 hrs, Volume= 0.93 cfs @ 12.17 hrs, Volume= for 1 OO-yr event 0.253 af 0.253 af, Atten= 80%, Lag= 11.4 min 0.253 af Routing by Stor-Ind method, Time Span= 0.00-25.00 hrs, dt= 0.01 hrs existing Prepared by Alliant Engineering, Inc. HydroCAO@ 7.10 sIn 001427 @ 2005 HydroCAO Software Solutions LLC Type /I 24-hr 100-yr' Rainfall=5.90" Page 15 8/30/2006 Peak Elev= 935.35' @ 12.17 hrs Surf.Area= 4,128 sf Storage= 3,013 cf Plug-Flow detention time= 17.0 min calculated for 0.253 af (100% of inflow) Center-of-Mass det. time= 17.0 min (792.6 - 775.6) Volume #1 Elevation (feet) 930.24 933.00 934.00 934.10 934.20 934.30 934.40 934.50 934.60 934.70 934.80 934.90 935.00 935.50 Device RoutinQ #1 Primary Invert 930.24' Avail.StoraQe StoraQe Description 3,646 cf Custom Stage Data (Prismatic) Listed below (Recalc) Surf.Area (sq-ft) 6 6 85 399 712 1,026 1,339 1,653 1,966 2,280 2,593 2,907 3,220 4,505 Inc.Store (cubic-feet) o 17 46 24 56 87 118 150 181 212 244 275 306 1,931 Cum.Store (cubic-feet) o 17 62 86 142 229 347 497 678 890 1,133 1 ,408 1,715 3,646 Invert Outlet Devices 930.24' 4.0" x 8.0' long Culvert RCP, sq.cut end projecting, Ke= 0.500 Outlet Invert= 929.97' S= 0.0337 '/' Cc= 0.900 n= 0.010 PVC, smooth interior Primary OutFlow Max=0.93 cfs @ 12.17 hrs HW=935.35' (Free Discharge) L1=Culvert (Inlet Controls 0.93 cfs @ 10.7 fps) Inflow Area = Inflow = Outflow = Primary = Pond E2: 48" CB 0.216 ac, Inflow Depth = 4.64" 1.80 cfs @ 11.94 hrs, Volume= 1.80 cfs @ 11.94 hrs, Volume= 1.80 cfs @ 11.94 hrs, Volume= for 1 OO-yr event 0.084 af 0.084 af, Atten= 0%, Lag= 0.1 min 0.084 af Routing by Stor-Ind method, Time Span= 0.00-25.00 hrs, dt= 0.01 hrs Peak Elev= 934.34' @ 11.94 hrs Surf.Area= 13 sf Storage= 10 cf Plug-Flow detention time= 0.4 min calculated for 0.084 af (100% of inflow) Center-of-Mass det. time= 0.4 min ( 783.5 - 783.2 ) Volume #1 Invert 933.61' Avail.StoraQe StoraQe Description 701 cf Custom Stage Data (Prismatic) Listed below (Recalc) existing Prepared by Alliant Engineering, Inc. HydroCAO@ 7.10 sin 001427 @2005 HydroCAO Software Solutions LLC Type II 24-hr 100-yr Rainfal/=5.90" Page 16 8/30/2006 Elevation (feet) 933.61 935.90 936.00 936.10 936.20 936.30 936.40 936.50 936.60 936.70 936.80 936.90 937.00 Device Routing #1 Primary Surf.Area (sq-ft) 13 13 40 93 162 251 359 489 673 915 1,193 1,514 2,040 Inc.Store ( cubic-feet) o 30 3 7 13 21 31 42 58 79 105 135 178 Cum. Store ( cubic-feet) o 30 32 39 52 72 103 145 203 283 388 524 701 I nvert Outlet Devices 933.61' 12.0" x 91.0' long Culvert RCP, sq.cut end projecting, Ke= 0.500 Outlet Invert= 931.88' S= 0.0190 '/' Cc= 0.900 n= 0.013 Concrete sewer w/manholes & inlets Primary OutFlow Max=1.80 cfs @ 11.94 hrs HW=934.34' (Free Discharge) L1=Culvert (Inlet Controls 1.80 cfs @ 2.9 fps) I nflow Area = Inflow = Primary = Link 1 L: MnDOT Ditch 1.054 ac, Inflow Depth = 3.84" for 100-yr event 2.68 cfs @ 11.98 hrs, Volume= 0.337 af 2.68 cfs @ 11.98 hrs, Volume= 0.337 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-25.00 hrs, dt= 0.01 hrs I nflow Area = Inflow = Primary = Link 2L: Car Wash Pond 0.486 ac, Inflow Depth = 3.14" for 1 OO-yr event 2.57 cfs @ 11.95 hrs, Volume= 0.127 af 2.57 cfs @ 11.95 hrs, Volume= 0.127 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-25.00 hrs, dt= 0.01 hrs Inflow Area = Inflow = Primary = Link 3L: Total 1.894 ac, Inflow Depth = 3.73" for 1 OO-yr event 7.64 cfs @ 11.97 hrs, Volume= 0.588 af 7.64 cfs @ 11.97 hrs, Volume= 0.588 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-25.00 hrs, dt= 0.01 hrs -- '" -)/" : /( I' ~,' /-j ,,' /,~(C;;i.:~E~jI:E_~~~~;~~~~~i1~'~~:~.-:=~' - , r. -. ,- --7'- / '--;.::,::;7 1 ,_ _ "-/- - - f' - -, I if ~,'''',I _L'-I.---;JO";';"'" --~\_,/ f "It'>, J'lt' //' ~ '-' 'I.', /' / \ \1', / o. ac ',' ' ____ \. ~/ ,tl \ 1/1 - I I, , If I' \ I' '-1 1 1 I f. ~ I 1\, "-t-/ ' I ------'" ,.~ ///" ,: / Ii';' I / , ,>, <, '\, ~, ":~ ~ , I ~ If I;, i,':" ~ i: ! :I:~ L ! /'--',- \ \ '" 1 I '. ,/ " I , I" " '1 ! v .' I I' I " I /"\ ~ II' ~ --, ',~ \ i II ,I I " , I j 'I I! : ! I 1: I IIi/ f~; h i i \ ~ /! "1\ ; I //):i,l 1/' /~/ / l / 11~,- / /"--;"'''' ~?'"'",;"llj:"/I,/(,,!,r:JF,',:"~~,,~,,,'~,'.,,,~,',:,... " /:/ " , f/>~: /;/; / /;' N' ' W.... 1':':'" " / />~?~i!J 1>( f {, - \ '\ " '-, f ,; /~I/ / ,,<~~.--.-'1 ..' . ,. \ \ " . / 1/'. / 1/1 ./j/~/.;~; ((! ! /i 0.19 ac \~\ \', " / ,{ 'I ( / / ' 1(" 1\1: ( {'r;j~r' \/\ '-~~, : II II : 1/:1/ :/irl\, ~~::~.)~~:~~~~'l-l,,~:.~;,-_--!~:;":'l~-r-:~ f - ,~ [/ \il\1 \\\\ ., ~,' r---...n--' 0-""'2' 1 / I " \, \ <. 'c,'c,>, ,~~t3;~~~~=~~;$~:.Z:~l~)~_:~,'~,:.,;,/_~.,__,,_;:~~~~,-,i~;~f,~~; ~~<';~;~<=: ~"<:,>_ -"~,.,l""^_I' '''~'r,,_,,' .... __ '--::_~-':_-:_-,-- f ,." "'", --': :~:::~-:--~}-~ ! \\ ---" / , , \ \~, " \ [>--.~ (/// / -~: -_._~,_._. / ~ '''''''''''~ -I 1/ LEGEND ----.... DRAINAGE BOUNDARY O' 40' SCALE IN FEET 80' 120' NORTH +- DRAINAGE DIRECTION UC.NO:_ ~ ~ ALLIANT 'X-;) ENGINEERlNG.INC !:\,~ PARI.. AVE. SOUTH, IIlIlTE ,~oo 1ol1;..1NEAPOLlll,MN M~I~ PHON~i612)7Il8'3080 'AX(Gl:z)7F.8-~19 I HEREBY COU1F'Y THAT ntS PLAN WAS PR(PAA(O BY ME OR UNDER: MY DIRECT SUPERVISION AND 1M... T I A~ A DULY UC[NSED PROFESSlON"'- [NGIN((R UNDER THE LAWS OF THE STA.TE OF WINNESQr" PRINT N"I>1(: SlCNED: PROPOSED DRAINAGE ABRA AUTO BODY & GLASS 40 LAKE DRIVE EAST CHANHASSEN,MN a-&C~1!'Cl 6y. ". Drown By. .LC 7 /28/O~ UwgNorTle: 06002.7 OIl~;9n"d By. O..l<;J" file: AIJTO BODY & GlASS DEOa2' (P-2) (P-1) ~& (0-1) ~t ~ct[J S,"lt";'9 A~ (P-3) (0-2) D't'"' ~~ Pond Sub (W-1) Wr ~ North Parking 2X3 BOX Offsite SE Total ~UbC~ B A ~ Drainage Diagram for proposed Prepared by Alliant Engineering, Inc. 8/30/2006 HydroCAD@7.10 sin 001427 @2005 HydroCAD Software Solutions LLC proposed Prepared by Alliant Engineering, Inc. HydroCAD@ 7.10 sIn 001427 <9 2005 HydroCAD Software Solutions LLC Type /I 24-hr 2-yr Rainfal/=2.70" Page 2 8/30/2006 Time span=O.OO-55.00 hrs, dt=0.01 hrs, 5501 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+ Trans method - Pond routing by Stor-Ind method Subcatchment 0-2: Offsite SE Runoff Area=3,939 sf Runoff Depth=0.26" Flow Length=44' Tc=6.1 min CN=61 Runoff=0.03 cfs 0.002 af Subcatchment 0-1: Offsite N Runoff Area=9,088 sf Runoff Depth=0.26" Flow Length=107' Tc=12.7 min CN=61 Runoff=0.04 cfs 0.004 af Subcatchment P-1: North Parking Runoff Area=11 ,006 sf Runoff Depth=2.36" Flow Length=122' Tc=1.8 min CN=97 Runoff=1.08 cfs 0.050 af Subcatchment P-2: South Parking Runoff Area=40,528 sf Runoff Depth=2.36" Flow Length=445' Tc=6.3 min CN=97 Runoff=3.44 cfs 0.183 af Subcatchment P-3: Pond Sub Runoff Area=9,738 sf Runoff Depth=1.48" Flow Length=70' Tc=3.8 min CN=87 Runoff=0.64 cfs 0.028 af Subcatchment W-1: Wetland Runoff Area=8,181 sf Runoff Depth=1.63" Flow Length=16' Tc=4.7 min CN=89 Runoff=0.56 cfs 0.026 af Pond P1: 2X3 BOX Peak Elev=933.23' Storage=9 cf Inflow=1.08 cfs 0.050 af Outflow=1.07 cfs 0.050 af Pond P3: Onsite Pond Peak Elev=934.85' Storage=15,322 cf Inflow=4.04 cfs 0.211 af Outflow=0.56 cfs 0.211 af Link 1 L: MnDOT Inflow=1.07 cfs 0.054 af Primary=1.07 cfs 0.054 af Link 2L: Car Wash Pond Inflow=0.56 cfs 0.213 af Primary=0.56 cfs 0.213 af Link 3L: Total Inflow=2.04 cfs 0.292 af Primary=2.04 cfs 0.292 af Total Runoff Area = 1.893 ac Runoff Volume = 0.292 af Average Runoff Depth = 1.85" proposed Prepared by Alliant Engineering, Inc. HydroCAO@ 7.10 sIn 001427 @2005 HydroCAO Software Solutions LLC Type /I 24-hr 2-yr Rainfal/=2.70" Page 3 8/30/2006 Runoff = Subcatchment 0-2: Offsite SE 0.03 cfs @ 12.01 hrs, Volume= 0.002 af, Depth= 0.26" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-55.00 hrs, dt= 0.01 hrs Type II 24-hr 2-yr Rainfall=2.70" Area (sf) 3,939 CN Description 61 >75% Grass cover, Good, HSG B Tc Length Slope Velocity Capacity Description (min) (feet) (ftlft) (ftlsec) (cfs) 6.1 44 0.0400 0.1 Sheet Flow, Grass: Dense n= 0.240 P2= 2.70" Runoff = Subcatchment 0-1: Offsite N 0.04 cfs @ 12.10 hrs, Volume= 0.004 af, Depth= 0.26" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-55.00 hrs, dt= 0.01 hrs Type II 24-hr 2-yr Rainfall=2.70" Area (sf) 9,088 CN Description 61 >75% Grass cover, Good, HSG B Tc Length Slope Velocity Capacity Description (min) (feet) (ftlft) (ftlsec) (cfs) 12.7 107 0.0380 0.1 Sheet Flow, Grass: Dense n= 0.240 P2= 2.70" Runoff = Subcatchment P-1: North Parking 1.08 cfs @ 11.92 hrs, Volume= 0.050 af, Depth= 2.36" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-55.00 hrs, dt= 0.01 hrs Type II 24-hr 2-yr Rainfall=2.70" Area (sf) 10,715 291 11,006 CN Description 98 Paved parking & roofs 61 >75% Grass cover, Good, HSG B 97 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ftlft) (fUsee) (cfs) 1.8 122 0.0139 1.1 Sheet Flow, Smooth surfaces n= 0.011 P2= 2.70" proposed Prepared by Alliant Engineering, Inc. HydroCAO@ 7.10 sIn 001427 @ 2005 HydroCAO Software Solutions LLC Type /I 24-hr 2-yr Rainfal/=2.70" Page 4 8/30/2006 Runoff = Subcatchment P-2: South Parking 3.44 cfs @ 11.97 hrs, Volume= 0.183 af, Depth= 2.36" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-55.00 hrs, dt= 0.01 hrs Type II 24-hr 2-yr Rainfall=2.70" Area (sf) 14,512 25,097 919 40,528 CN Description 98 building 98 parking 61 >75% Grass cover, Good, HSG B 97 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ftlfl) (ftlsec) (ds) 1.5 106 0.0163 1.2 Sheet Flow, Smooth surfaces n= 0.011 P2= 2.70" 4.8 339 0.0033 1.2 Shallow Concentrated Flow, Paved Kv= 20.3 fps 6.3 445 Total Runoff = Subcatchment P-3: Pond Sub 0.64 ds @ 11.95 hrs, Volume= 0.028 af, Depth= 1.48" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-55.00 hrs, dt= 0.01 hrs Type II 24-hr 2-yr Rainfall=2.70" Area (sf) 6,504 3,234 9,738 CN Description 100 Pond 61 >75% Grass cover, Good, HSG B 87 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ftlfl) (ftlsec) (ds) 3.8 70 0.3333 0.3 Sheet Flow, Grass: Dense n= 0.240 P2= 2.70" Runoff = Subcatchment W-1: Wetland 0.56 cfs @ 11.96 hrs, Volume= 0.026 af, Depth= 1.63" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-55.00 hrs, dt= 0.01 hrs Type II 24-hr 2-yr Rainfall=2.70" Area (sf) 5,813 2,368 8,181 CN Description 100 Wetland Edge 61 >75% Grass cover, Good, HSG B 89 Weighted Average proposed Prepared by Alliant Engineering, Inc. HydroCAD@ 7.10 sIn 001427 @ 2005 HydroCAD Software Solutions LLC Type /I 24-hr 2-yr Rainfal/=2.70" Page 5 8/30/2006 Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (ds) 4.7 16 0.0100 0.1 Sheet Flow, Grass: Dense n= 0.240 P2= 2.70" Pond P1: 2X3 BOX Inflow Area = Inflow = Outflow = Primary = 0.253 ac, Inflow Depth = 2.36" 1.08 cfs @ 11.92 hrs, Volume= 1.07 cfs @ 11.92 hrs, Volume= 1.07 cfs @ 11.92 hrs, Volume= for 2-yr event 0.050 af 0.050 af, Atten= 1%, Lag= 0.2 min 0.050 af Routing by Stor-Ind method, Time Span= 0.00-55.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 933.23' @ 11.92 hrs Surf.Area= 6 sf Storage= 9 cf Plug-Flow detention time= 0.3 min calculated for 0.050 af (100% of inflow) Center-of-Mass det. time= 0.3 min ( 763.3 - 763.0 ) Volume #1 Invert 931.70' Avail.StoraQe StoraQe Description 216 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area (feet) (sq-ft) 931.70 6 935.30 6 935.40 87 935.50 174 935.60 218 935.70 305 935.80 392 935.90 479 936.00 566 Device RoutinQ Invert #1 Primary 931.70' #2 Primary 935.80' Inc.Store (cubic-feet) o 22 5 13 20 26 35 44 52 Cum. Store ( cubic-feet) o 22 26 39 59 85 120 163 216 Outlet Devices 6.0" x 61.0' long Culvert RCP, sq.cut end projecting, Ke= 0.500 Outlet Invert= 929.97' S= 0.0284 'I' Cc= 0.900 n= 0.010 PVC, smooth interior 10.0' long x 3.0' 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 Coef. (English) 2.44 2.58 2.68 2.67 2.65 2.64 2.64 2.68 2.68 2.72 2.81 2.92 2.97 3.07 3.32 Primary OutFlow Max=1.06 cfs @ 11.92 hrs HW=933.22' (Free Discharge) t1 =Culvert (Inlet Controls 1.06 cfs @ 5.4 fps) 2=Broad-Crested Rectangular Weir (Controls 0.00 cfs) proposed Prepared by Alliant Engineering, Inc. HydroCAD@ 7.10 sIn 001427 @ 2005 HydroCAD Software Solutions LLC Type /I 24-hr 2-yr Rainfal/=2.70" Page 6 8/30/2006 Inflow Area = Inflow = Outflow = Primary = Pond P3: Onsite Pond 1.154 ac, Inflow Depth = 2.19" 4.04 cfs @ 11.97 hrs, Volume= 0.56 cfs @ 12.21 hrs, Volume= 0.56 cfs @ 12.21 hrs, Volume= for 2-yr event 0.211 af 0.211 af, Atten= 86%, Lag= 14.5 min 0.211 af Routing by Stor-Ind method, Time Span= 0.00-55.00 hrs, dt= 0.01 hrs I 2 Starting Elev= 934.50' Surf.Area= 11,683 sf Storage= 11,142 cf Peak Elev= 934.85' @ 12.21 hrs Surf.Area= 12,493 sf Storage= 15,322 cf (4,181 cf above start) Flood Elev= 936.00' Surf.Area= 19,011 sf Storage= 33,209 cf (22,067 cf above start) Plug-Flow detention time= (not calculated: initial storage excedes outflow) Center-of-Mass det. time= 126.4 min ( 900.6 - 774.2 ) Volume #1 Elevation (feet) 931.00 932.00 933.00 934.00 934.50 935.00 936.00 Device #1 Routin~ Primary #2 Device 1 #3 Device 1 Invert 931.00' Avail.Storage Storage Description 33,209 cf Custom Stage Data (Prismatic) Listed below (Recalc) Surf. Area (sq-ft) 826 1,841 2,922 4,060 11,683 12,854 19,011 Inc.Store ( cubic-feet) o 1,334 2,382 3,491 3,936 6,134 15,933 Cum.Store ( cubic-feet) o 1,334 3,715 7,206 11,142 17,276 33,209 Invert Outlet Devices 932.67' 12.0" x 79.0' long Culvert RCP, square edge headwall, Ke= 0.500 Outlet Invert= 931.88' S= 0.0100 'I' Cc= 0.900 n= 0.013 Concrete sewer w/manholes & inlets 935.40' 4.0' long x 0.5' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 Coef. (English) 2.80 2.92 3.08 3.30 3.32 934.50' 6.0" Horiz. Orifice/Grate Limited to weir flow C= 0.600 Primary OutFlow Max=0.56 cfs @ 12.21 hrs HW=934.85' (Free Discharge) L1=Culvert (Passes 0.56 cfs of 4.43 cfs potential flow) t2=Broad-crested Rectangular Weir (Controls 0.00 cfs) 3=Orifice/Grate (Orifice Controls 0.56 cfs @ 2.8 fps) Inflow Area = Inflow = Primary = Link1L:MnDOT 0.461 ac, Inflow Depth = 1.41" for 2-yr event 1.07 cfs @ 11.92 hrs, Volume= 0.054 af 1.07 cfs @ 11.92 hrs, Volume= 0.054 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-55.00 hrs, dt= 0.01 hrs proposed Prepared by Alliant Engineering, Inc. HydroCAD@ 7.10 sIn 001427 @2005 HydroCAD Software Solutions LLC Type /I 24-hr 2-yr Rainfaf/=2.70" Page 7 8/30/2006 Link 2L: Car Wash Pond Inflow Area = Inflow = Primary = 1.244 ac, Inflow Depth = 2.05" for 2-yr event 0.56 cfs @ 12.16 hrs, Volume= 0.213 af 0.56 cfs @ 12.16 hrs, Volume= 0.213 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-55.00 hrs, dt= 0.01 hrs Link 3L: Total I nflow Area = Inflow = Primary = 1.893 ac, Inflow Depth = 1.85" for 2-yr event 2.04 cfs @ 11.93 hrs, Volume= 0.292 af 2.04 cfs @ 11.93 hrs, Volume= 0.292 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-55.00 hrs, dt= 0.01 hrs proposed Prepared by Alliant Engineering, Inc. HydroCAD@ 7.10 sIn 001427 @ 2005 HydroCAD Software Solutions LLC Type /I 24-hr 10-yr Rainfal/=4.10" Page 8 8/30/2006 Time span=O.OO-55.00 hrs, dt=0.01 hrs, 5501 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+ Trans method - Pond routing by Stor-Ind method Subcatchment 0-2: Offsite SE Runoff Area=3,939 sf Runoff Depth=0.86" Flow Length=44' Tc=6.1 min CN=61 Runoff=0.13 cfs 0.007 af Subcatchment 0-1: Offsite N Runoff Area=9,088 sf Runoff Depth=0.86" Flow Length=1 01' Tc=12.7 min CN=61 Runoff=0.22 cfs 0.015 af Subcatchment P-1: North Parking Runoff Area=11,006 sf Runoff Depth=3.75" Flow Length=122' Tc=1.8 min CN=97 Runoff=1.66 cfs 0.079 af Subcatchment P-2: South Parking Runoff Area=40,528 sf Runoff Depth=3.75" Flow Length=445' Tc=6.3 min CN=97 Runoff=5.32 cfs 0.291 af Subcatchment P-3: Pond Sub Runoff Area=9,738 sf Runoff Depth=2.73" Flow Length=70' Tc=3.8 min CN=87 Runoff=1.14 cfs 0.051 af Subcatchment W-1: Wetland Runoff Area=8, 181 sf Runoff Depth=2.92" Flow Length=16' Tc=4.7 min CN=89 Runoff=0.98 cfs 0.046 af Pond P1: 2X3 BOX Peak Elev=935.16' Storage=21 cf Inflow=1.66 cfs 0.079 af Outflow=1.64 cfs 0.079 af Pond P3: Onsite Pond Peak Elev=935.05' Storage=17,991 cf Inflow=6.39 cfs 0.342 af Outflow=0.70 cfs 0.342 af Link 1 L: MnDOT Inflow=1.71 cfs 0.094 af Primary=1.71 cfs 0.094 af Link 2L: Car Wash Pond Inflow=O.77 cfs 0.348 af Primary=O.77 cfs 0.348 af Link 3L: Total Inflow=3.31 cfs 0.488 af Primary=3.31 cfs 0.488 af Total Runoff Area = 1.893 ac Runoff Volume = 0.488 af Average Runoff Depth = 3.09" proposed Prepared by Alliant Engineering, Inc. HydroCAO@ 7.10 sin 001427 @ 2005 HydroCAO Software Solutions LLC Type 1/ 24-hr 10-yr Rainfal/=4.10" Page 9 8/30/2006 Runoff = Subcatchment 0-2: Offsite SE 0.13 cfs @ 11.99 hrs, Volume= 0.007 af, Depth= 0.86" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-55.00 hrs, dt= 0.01 hrs Type II 24-hr 10-yr Rainfall=4.10" Area (sf) 3,939 CN Description 61 >75% Grass cover, Good, HSG B Tc Length Slope Velocity Capacity Description (min) (feet) (fUn) (fUsee) (cfs) 6.1 44 0.0400 0.1 Sheet Flow, Grass: Dense n= 0.240 P2= 2.70" Runoff = Subcatchment 0-1: Offsite N 0.22 cfs @ 12.07 hrs, Volume= 0.015 af, Depth= 0.86" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-55.00 hrs, dt= 0.01 hrs Type II 24-hr 10-yr Rainfall=4.10" Area (sf) 9,088 CN Description 61 >75% Grass cover, Good, HSG B Tc Length Slope Velocity Capacity Description (min) (feet) (fUn) (fUsee) (cfs) 12.7 107 0.0380 0.1 Sheet Flow, Grass: Dense n= 0.240 P2= 2.70" Runoff = Subcatchment P-1: North Parking 1.66 cfs @ 11.92 hrs, Volume= 0.079 af, Depth= 3.75" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-55.00 hrs, dt= 0.01 hrs Type II 24-hr 10-yr Rainfall=4.10" Area (sf) 10,715 291 11,006 CN Description 98 Paved parking & roofs 61 >75% Grass cover, Good, HSG B 97 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (fUn) (ft/sec) (cfs) 1.8 122 0.0139 1.1 Sheet Flow, Smooth surfaces n= 0.011 P2= 2.70" proposed Prepared by Alliant Engineering, Inc. HydroCAO@ 7.10 sin 001427 @2005 HydroCAO Software Solutions LLC Type II 24-hr 10-yr Rainfal/=4.10" Page 1 0 8/30/2006 Runoff = Subcatchment P-2: South Parking 5.32 cfs @ 11.97 hrs, Volume= 0.291 af, Depth= 3.75" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-55.00 hrs, dt= 0.01 hrs Type II 24-hr 10-yr Rainfall=4.10" Area (sf) 14,512 25,097 919 40,528 CN Description 98 building 98 parking 61 >75% Grass cover, Good, HSG B 97 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ftlft) (ftlsec) (cfs) 1.5 106 0.0163 1.2 Sheet Flow, Smooth surfaces n= 0.011 P2= 2.70" 4.8 339 0.0033 1.2 Shallow Concentrated Flow, Paved Kv= 20.3 fps 6.3 445 Total Runoff = Subcatchment P-3: Pond Sub 1.14 cfs @ 11.95 hrs, Volume= 0.051 af, Depth= 2.73" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-55.00 hrs, dt= 0.01 hrs Type II 24-hr 10-yr Rainfall=4.10" Area (sf) 6,504 3,234 9,738 CN Description 100 Pond 61 >75% Grass cover, Good, HSG B 87 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ftlft) (ftlsec) (cfs) 3.8 70 0.3333 0.3 Sheet Flow, Grass: Dense n= 0.240 P2= 2.70" Runoff = Subcatchment W-1: Wetland 0.98 cfs @ 11.96 hrs, Volume= 0.046 af, Depth= 2.92" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-55.00 hrs, dt= 0.01 hrs Type II 24-hr 10-yr Rainfall=4.10" Area (sf) 5,813 2,368 8,181 CN Description 100 Wetland Edge 61 >75% Grass cover, Good, HSG B 89 Weighted Average proposed Prepared by Alliant Engineering, Inc. HydroCAO@ 7.10 sIn 001427 @ 2005 HydroCAO Software Solutions LLC Type /I 24-hr 10-yr Rainfal/=4.10" Page 11 8/30/2006 Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (fUsee) (cfs) 4.7 16 0.0100 0.1 Sheet Flow, Grass: Dense n= 0.240 P2= 2.70" Pond P1: 2X3 BOX Inflow Area = Inflow = Outflow = Primary = 0.253 ac, Inflow Depth = 3.75" 1.66 cfs @ 11.92 hrs, Volume= 1.64 cfs @ 11.93 hrs, Volume= 1.64 cfs @ 11.93 hrs, Volume= for 1 O-yr event 0.079 af 0.079 af, Atten= 2%, Lag= 0.4 min 0.079 af Routing by Stor-Ind method, Time Span= 0.00-55.00 hrs, dt= 0.01 hrs /2 Peak Elev= 935.16' @ 11.93 hrs Surf.Area= 6 sf Storage= 21 cf Plug-Flow detention time= 0.3 min calculated for 0.079 af (100% of inflow) Center-of-Mass det. time= 0.2 min ( 752.6 - 752.4 ) Volume #1 Invert 931.70' Avail.Stora~e Stora~e Description 216 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area (feet) (sq-ft) 931.70 6 935.30 6 935.40 87 935.50 174 935.60 218 935.70 305 935.80 392 935.90 479 936.00 566 Device Routin~ Invert #1 Primary 931.70' #2 Primary 935.80' Inc.Store (cubic-feet) o 22 5 13 20 26 35 44 52 Cum.Store ( cubic-feet) o 22 26 39 59 85 120 163 216 Outlet Devices 6.0" x 61.0' long Culvert RCP, sq.cut end projecting, Ke= 0.500 Outlet Invert= 929.97' S= 0.0284 '/' Cc= 0.900 n= 0.010 PVC, smooth interior 10.0' long x 3.0' 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 Coef. (English) 2.44 2.58 2.68 2.67 2.65 2.64 2.64 2.68 2.68 2.72 2.81 2.92 2.97 3.07 3.32 Primary OutFlow Max=1.63 cfs @ 11.93 hrs HW=935.13' (Free Discharge) t1=culvert (Barrel Controls 1.63 cfs @ 8.3 fps) 2=Broad-Crested Rectangular Weir (Controls 0.00 cfs) proposed Prepared by Alliant Engineering, Inc. HydroCAD@ 7.10 sIn 001427 @ 2005 HydroCAD Software Solutions LLC Type 1/24-hr 10-yr Rainfal/=4.10" Page 12 8/30/2006 Inflow Area = Inflow = Outflow = Primary = Pond P3: Onsite Pond 1.154 ac, Inflow Depth = 3.55" 6.39 cfs @ 11.96 hrs, Volume= 0.70 cfs @ 12.30 hrs, Volume= 0.70 cfs @ 12.30 hrs, Volume= for 1 O-yr event 0.342 af 0.342 af, Atten= 89%, Lag= 20.4 min 0.342 af Routing by Stor-Ind method, Time Span= 0.00-55.00 hrs, dt= 0.01 hrs 1 2 Starting Elev= 934.50' Surf.Area= 11,683 sf Storage= 11,142 cf Peak Elev= 935.05' @ 12.30 hrs Surf.Area= 13,192 sf Storage= 17,991 cf (6,849 cf above start) Flood Elev= 936.00' Surf.Area= 19,011 sf Storage= 33,209 cf (22,067 cf above start) Plug-Flow detention time= 650.9 min calculated for 0.086 af (25% of inflow) Center-of-Mass det. time= 134.6 min ( 898.2 - 763.5 ) Volume #1 Elevation (feet) 931.00 932.00 933.00 934.00 934.50 935.00 936.00 Device #1 Routing Primary #2 Device 1 #3 Device 1 Invert 931.00' Avail.Storage Storage Description 33,209 cf Custom Stage Data (Prismatic) Listed below (Recalc) Surf.Area (sq-ft) 826 1,841 2,922 4,060 11 ,683 12,854 19,011 Inc.Store ( cubic-feet) o 1,334 2,382 3,491 3,936 6,134 15,933 Cum.Store ( cubic-feet) o 1,334 3,715 7,206 11,142 17,276 33,209 Invert Outlet Devices 932.67' 12.0" x 79.0' long Culvert RCP, square edge headwall, Ke= 0.500 Outlet Invert= 931.88' S= 0.0100 'I' Cc= 0.900 n= 0.013 Concrete sewer w/manholes & inlets 935.40' 4.0' long x 0.5' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 Coef. (English) 2.80 2.92 3.08 3.30 3.32 934.50' 6.0" Horiz. Orifice/Grate Limited to weir flow C= 0.600 Primary OutFlow Max=0.70 cfs @ 12.30 hrs HW=935.05' (Free Discharge) "Lt-CUlvert (Passes 0.70 cfs of 4.66 cfs potential flow) 2=Broad-Crested Rectangular Weir (Controls 0.00 cfs) 3=Orifice/Grate (Orifice Controls 0.70 cfs @ 3.6 fps) I nflow Area = Inflow = Primary = Link 1 L: MnDOT 0.461 ac, Inflow Depth = 2.45" for 10-yr event 1.71 cfs@ 11.93hrs, Volume= 0.094af 1.71 cfs @ 11.93 hrs, Volume= 0.094 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-55.00 hrs, dt= 0.01 hrs proposed Prepared by Alliant Engineering, Inc. HydroCAD@ 7.10 sIn 001427 @2005 HydroCAD Software Solutions LLC Type /I 24-hr 10-yr Rainfal/=4.10" Page 13 8/30/2006 Link 2L: Car Wash Pond Inflow Area = Inflow = Primary = 1.244 ac, Inflow Depth = 3.36" for 10-yr event 0.77 cfs @ 12.02 hrs, Volume= 0.348 af 0.77 cfs @ 12.02 hrs, Volume= 0.348 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-55.00 hrs, dt= 0.01 hrs Link 3L: Total Inflow Area = Inflow = Primary = 1.893 ac, Inflow Depth = 3.09" for 10-yr event 3.31 cfs @ 11.94 hrs, Volume= 0.488 af 3.31 cfs @ 11.94 hrs, Volume= 0.488 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-55.00 hrs, dt= 0.01 hrs proposed Prepared by Alliant Engineering, Inc. HydroCAD@7.10 sIn 001427 @2005 HydroCAD Software Solutions LLC Type /I 24-hr 100-yr Rainfal/=5.90" Page 14 8/30/2006 Time span=O.OO-55.00 hrs, dt=O.01 hrs, 5501 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+ Trans method - Pond routing by Stor-Ind method Subcatchment 0-2: Offsite SE Runoff Area=3,939 sf Runoff Depth=1.94" Flow Length=44' Tc=6.1 min CN=61 Runoff=0.31 efs 0.015 af Subcatchment 0-1: Offsite N Runoff Area=9,088 sf Runoff Depth=1.94" Flow Length=10T Te=12.7 min CN=61 Runoff=0.55 efs 0.034 af Subcatchment P-1: North Parking Runoff Area=11 ,006 sf Runoff Depth=5.54" Flow Length=122' Te=1.8 min CN=97 Runoff=2.41 cfs 0.117 af Subcatchment P-2: South Parking Runoff Area=40,528 sf Runoff Depth=5.54" Flow Length=445' Te=6.3 min CN=97 Runoff=7.71 efs 0.430 af Subcatchment P-3: Pond Sub Runoff Area=9,738 sf Runoff Depth=4.42" Flow Length=70' Te=3.8 min CN=87 Runoff=1.79 efs 0.082 af Subcatchment W-1: Wetland Runoff Area=8,181 sf Runoff Depth=4.64" Flow Length=16' Te=4.7 min CN=89 Runoff=1.51 efs 0.073 af Pond P1: 2X3 BOX Peak Elev=935.86' Storage=147 ef Inflow=2.41 efs 0.117 af Outflow=2.16 cfs 0.117 af Pond P3: Onsite Pond Peak Elev=935.31' Storage=21 ,545 ef Inflow=9.39 efs 0.512 af Outflow=0.85 efs 0.512 af Link 1L: MnDOT Inflow=2.47 efs 0.150 af Primary=2.47 efs 0.150 af Link 2L: Car Wash Pond Inflow=1.07 efs 0.527 af Primary=1.07 efs 0.527 af Link 3L: Total Inflow=4.95 efs 0.750 af Primary=4.95 efs 0.750 af Total Runoff Area = 1.893 ac Runoff Volume = 0.750 af Average Runoff Depth = 4.75" proposed Prepared by Alliant Engineering, Inc. HydroCAO@ 7.10 sin 001427 <92005 HydroCAO Software Solutions LLC Type /I 24-hr 100-yr Rainfal/=5.90" Page 15 8/30/2006 Subcatchment 0-2: Offsite SE Runoff 0.31 cfs @ 11.98 hrs, Volume= 0.015 af, Depth= 1.94" = Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-55.00 hrs, dt= 0.01 hrs Type II 24-hr 100-yr Rainfall=5.90" Area (sf) 3,939 CN Description 61 > 75% Grass cover, Good, HSG B Tc Length Slope Velocity Capacity Description (min) (feet) (ftlft) (ftlsec) (cfs) 6.1 44 0.0400 0.1 Sheet Flow, Grass: Dense n= 0.240 P2= 2.70" Subcatchment 0-1: Offsite N Runoff 0.55 cfs @ 12.06 hrs, Volume= 0.034 af, Depth= 1.94" = Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-55.00 hrs, dt= 0.01 hrs Type II 24-hr 100-yr Rainfall=5.90" Area (sf) 9,088 CN Description 61 >75% Grass cover, Good, HSG B Tc Length Slope Velocity Capacity Description (min) (feet) (fUft) (ftlsec) (cfs) 12.7 107 0.0380 0.1 Sheet Flow, Grass: Dense n= 0.240 P2= 2.70" Subcatchment P-1: North Parking Runoff 2.41 cfs @ 11.92 hrs, Volume= 0.117 af, Depth= 5.54" = Runoff by SCS TR-20 method, UH';'SCS, Time Span= 0.00-55.00 hrs, dt= 0.01 hrs Type II 24-hr 100-yr Rainfall=5.90" Area (sf) 10,715 291 11 ,006 CN Description 98 Paved parking & roofs 61 >75% Grass cover, Good, HSG B 97 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ftlft) (ftIsec) (cfs) 1.8 122 0.0139 1.1 Sheet Flow, Smooth surfaces n= 0.011 P2= 2.70" proposed Prepared by Alliant Engineering, Inc. HydroCAD@ 7.10 sIn 001427 @ 2005 HydroCAD Software Solutions LLC Type //24-hr 100-yr Rainfal/=5.90" Page 16 8/30/2006 Runoff = Subcatchment P-2: South Parking 7.71 cfs @ 11.97 hrs, Volume= 0.430 af, Depth= 5.54" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-55.00 hrs, dt= 0.01 hrs Type II 24-hr 100-yr Rainfall=5.90" Area (sf) 14,512 25,097 919 40,528 CN Description 98 building 98 parking 61 >75% Grass cover, Good, HSG B 97 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ftIft) (ftIsec) (cfs) 1.5 106 0.0163 1.2 Sheet Flow, Smooth surfaces n= 0.011 P2= 2.70" 4.8 339 0.0033 1.2 Shallow Concentrated Flow, Paved Kv= 20.3 fps 6.3 445 Total Runoff = Subcatchment P-3: Pond Sub 1.79 cfs @ 11.94 hrs, Volume= 0.082 af, Depth= 4.42" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-55.00 hrs, dt= 0.01 hrs Type II 24-hr 100-yr Rainfall=5.90" Area (sf) 6,504 3,234 9,738 CN Description 100 Pond 61 >75% Grass cover, Good, HSG B 87 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ftIft) (ftIsec) (cfs) 3.8 70 0.3333 0.3 Sheet Flow, Grass: Dense n= 0.240 P2= 2.70" Runoff = Subcatchment W-1 : Wetland 1.51 cfs @ 11.95 hrs, Volume= 0.073 af, Depth= 4.64" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-55.00 hrs, dt= 0.01 hrs Type II 24-hr 100-yr Rainfall=5.90" Area (sf) 5,813 2,368 8,181 eN Description 1 00 Wetland Edge 61 >75% Grass cover, Good, HSG B 89 Weighted Average proposed Prepared by Alliant Engineering, Inc. HydroCAO@ 7.10 sin 001427 @2005 HydroCAO Software Solutions LLC Type /I 24-hr 100-yr Rainfal/=5.90" Page 17 8/30/2006 Tc Length Slope Velocity Capacity Description (min) (feet) (fUft) (fUsec) (cfs) 4.7 16 0.0100 0.1 Sheet Flow, Grass: Dense n= 0.240 P2= 2.70" Pond P1: 2X3 BOX Inflow Area = Inflow = Outflow = Primary = 0.253 ac, Inflow Depth = 5.54" 2.41 cfs @ 11.92 hrs, Volume= 2.16 cfs@ 11.94 hrs, Volume= 2.16 cfs @ 11.94 hrs, Volume= for 1 OO-yr event 0.117 af 0.117 af, Atten= 10%, Lag= 1.4 min 0.117 af Routing by Stor-Ind method, Time Span= 0.00-55.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 935.86' @ 11.94 hrs Surf.Area= 448 sf Storage= 147 cf Plug-Flow detention time= 0.5 min calculated for 0.117 af (100% of inflow) Center-of-Mass del. time= 0.4 min (745.0 - 744.6 ) Volume #1 Invert 931.70' Avail.Stora~e Storage Description 216 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area (feet) (sq-ft) 931.70 6 935.30 6 935.40 87 935.50 174 935.60 218 935.70 305 935.80 392 935.90 479 936.00 566 Device Routing Invert #1 Primary 931.70' #2 Primary 935.80' Inc.Store (cubic-feet) o 22 5 13 20 26 35 44 52 Cum. Store (cubic-feet) o 22 26 39 59 85 120 163 216 Outlet Devices 6.0" x 61.0' long Culvert RCP, sq.cut end projecting, Ke= 0.500 Outlet Invert= 929.97' S= 0.0284 '/' Cc= 0.900 n= 0.010 PVC, smooth interior 10.0' long x 3.0' 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 Coef. (English) 2.44 2.58 2.68 2.67 2.65 2.64 2.64 2.68 2.68 2.72 2.81 2.92 2.97 3.07 3.32 Primary OutFlow Max=2.13 cfs @ 11.94 hrs HW=935.86' (Free Discharge) t1=culvert (Barrel Controls 1.75 cfs @ 8.9 fps) 2=Broad-Crested Rectangular Weir (Weir Controls 0.38 cfs @ 0.6 fps) proposed Prepared by Alliant Engineering, Inc. HydroCAD@ 7.10 sIn 001427 @2005 HydroCAD Software Solutions LLC Type 1/24-hr 100-yr Rainfal/=5.90" Page 18 8/30/2006 Inflow Area = Inflow = Outflow = Primary = Pond P3: Onsite Pond 1.154 ac, Inflow Depth = 5.33" 9.39 cfs @ 11.96 hrs, Volume= 0.85 cfs @ 12.42 hrs, Volume= 0.85 cfs @ 12.42 hrs, Volume= for 1 OO-yr event 0.512 af 0.512 af, Atten= 91%, Lag= 27.3 min 0.512 af Routing by Stor-Ind method, Time Span= 0.00-55.00 hrs, dt= 0.01 hrs / 2 Starting Elev= 934.50' Surf.Area= 11,683 sf Storage= 11,142 cf Peak Elev= 935.31' @ 12.42 hrs Surf.Area= 14,758 sf Storage= 21,545 cf (10,403 cf above start) Flood Elev= 936.00' Surf.Area= 19,011 sf Storage= 33,209 cf (22,067 cf above start) Plug-Flow detention time= 455.2 min calculated for 0.256 af (50% of inflow) Center-of-Mass del. time= 149.9 min ( 905.3 - 755.4 ) Volume #1 Elevation (feet) 931.00 932.00 933.00 934.00 934.50 935.00 936.00 Device Routin~ #1 Primary #2 Device 1 #3 Device 1 Invert 931.00' Avail.Stora~e Stora~e Description 33,209 cf Custom Stage Data (Prismatic) Listed below (Recalc) Surf.Area ( sq-ft) 826 1,841 2,922 4,060 11,683 12,854 19,011 Inc.Store ( cubic-feet) o 1,334 2,382 3,491 3,936 6,134 15,933 Cum.Store ( cubic-feet) o 1,334 3,715 7,206 11,142 17,276 33,209 Invert Outlet Devices 932.67' 12.0" x 79.0' long Culvert RCP, square edge headwall, Ke= 0.500 Outlet Invert= 931.88' S= 0.0100 'I' Cc= 0.900 n= 0.013 Concrete sewer w/manholes & inlets 935.40' 4.0' long x 0.5' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 Coef. (English) 2.80 2.92 3.08 3.30 3.32 934.50' 6.0" Horiz. Orifice/Grate Limited to weir flow C= 0.600 Primary OutFlow Max=0.85 cfs @ 12.42 hrs HW=935.31' (Free Discharge) L1=Culvert (Passes 0.85 cfs of 4.92 cfs potential flow) t2=Broad-Crested Rectangular Weir (Controls 0.00 cfs) 3=Orifice/Grate (Orifice Controls 0.85 cfs @ 4.3 fps) Inflow Area = Inflow = Primary = Link 1 L: MnDOT 0.461 ac, Inflow Depth = 3.91" for 100-yr event 2.47 cfs @ 11.95 hrs, Volume= 0.150 af 2.47 cfs @ 11.95 hrs, Volume= 0.150 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-55.00 hrs, dt= 0.01 hrs proposed Prepared by Alliant Engineering, Inc. HydroCAD@ 7.10 sIn 001427 @ 2005 HydroCAD Software Solutions LLC Type II 24-hr 100-yr Rainfal/=5.90" Page 19 8/30/2006 Link 2L: Car Wash Pond Inflow Area = Inflow = Primary = 1.244 ac, Inflow Depth = 5.08" for 100-yr event 1.07 cfs @ 12.00 hrs, Volume= 0.527 af 1.07 cfs @ 12.00 hrs, Volume= 0.527 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-55.00 hrs, dt=0.01 hrs Link 3L: Total Inflow Area = Inflow = Primary = 1.893 ac, Inflow Depth = 4.75" for 100-yr event 4.95 cfs @ 11.95 hrs, Volume= 0.750 af 4.95 cfs @ 11.95 hrs, Volume= 0.750 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-55.00 hrs, dt= 0.01 hrs ~ ~ a ~ ~ co I'- I'- ~ ~ I!) I'- a N C") a a I'- C") ... co ~ C") co N co C") N N C") ..- ..- C") co I'- I!) I!) N I'- >- 00 I!) a ..- I!) C") ..- ..- a a ..- ~ a a I'- ..- I!) a ...... ' 00 NO 0 0 0 0 0 0 0 0 00 ;:::0 a a a a a ,0 CJ.... lU ...... CIl a m ~ C") I!) ..- ~N I!) I!) I'- m ...... ..- co co ~ coco E ... ~ ..- co I!) 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