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Stormwater Report 07-24-2014STORMWATER ANALYSIS The Village Shoppes of Chanhassen Chanhassen, MN Prepared for: Chanhassen Retail, LLC 1508 Welland Avenue Minnetonka, MN 55305 Phone (952)-852-2339 Prepared by: Westwood Professional Services, Inc. 7699 Anagram Drive Eden Prairie, MN 55344 Phone (952) 937-5150, Fax (952) 937-5822 July 24, 2014 Project # 0000220 PROJECT DESCRIPTION The project site is located on the northeast corner of Lake Drive East and Main Street in Chanhassen. The existing property is 13.358 acres. The proposed project is a proposed 14,000 square foot retail/restaurant on the 1.4 acre site. The actual are of disturbance will be approximately 0.92 acres. Existing and Proposed Site Areas Existing Total 61,057 sf 1.402 acres Impervious 22,105 sf 0.507 acres 52.6% Pervious 38,952 sf 0.665 acres 47.4% Proposed Total 61,057 sf 1.402 acres Impervious 55,090 sf 1.265 acres 90.2% Pervious 5,965 sf 0.137 acres 9.8% EXISTING SITE CONDITIONS The existing site where the proposed project is prosed is currently undeveloped. There is an existing parking on the southeast corner of the site that will connect to the proposed project. The existing drainage from the undeveloped site drains to the south into Lake East Drive. The existing site was accounted for in the NURP pond south of the site as part of Villages on the Ponds project. PROPOSED SITE CONDITIONS The proposed project will have an underground StormTech SC-740 Chamber system that will treat the runoff from the 1.1” rain fall event. There will be two roof drains that will discharge into the system as well as a catch basin in the southeast corner of the proposed work. The underground system will than discharge into the catch basin in the existing driveway entrance. REGULATORY REQUIREMENTS Riley Purgatory Bluff Creek Watershed District will complete the review of the stormwater management design for this project. For a new development, the following rules apply; Water Quality – Infiltration - Removal of 75% of phosphorus and 90% total suspended solids. 1.1 inch of runoff from impervious surface onsite. Rate Control - Peak runoff rates may not exceed the existing rates for the 2, 10 and 100- year critical storm events set forth by NOAA Atlas 14 Volume 8. Water Quality - Infiltration The Riley Purgatory Bluff Creek Watershed District requires that proposed projects infiltrate stormwater from the 1.1” storm event over all new impervious areas. Due to poor D soils onsite our plan is to use a filtration system. Our proposed plan is to provide an underground filtration system to provide treatment. The proposed plan is to use (6) rows of (8) Chambers per row of StormTech SC-740 Chamber System with 18” of sand below the system with draintile. The proposed system will have a 12” outlet that is 3.5 feet above the bottom of the sand layer and draintile The following is the storage area required to provide the volume from the 1.1” runoff . 32,985 SF x 1.1 in x 1ft/12in = 3,024 CF = 0.069 acre-feet There will be 0.081 acre-feet of storage provided from the 1.5 (IE=941.0) layer of sand and the first 1.5 feet (IE=944.5) of the StormTech system to meet the watershed requirements. See underground system volume calculations at end of report for required volume. Rate Control The following table summarizes the pre-development and post-development runoff rates. Existing Conditions Storm Event 2-Year (2.87”) (cfs) 10-Year (4.29”) (cfs) 100-Year (7.39”) (cfs) Total Existing 2.92 5.11 10.05 Proposed Conditions Storm Event 2-Year (2.87”) (cfs) 10-Year (4.29”) (cfs) 100-Year (7.39”) (cfs) Total Proposed 2.88 4.23 9.44 EXISTING CONDITIONS HYDROLOGY ANALYSIS 1E Existing Site Routing Diagram for The Shoppes of Chanhassen Prepared by Westwood Professional Services, Inc., Printed 7/24/2014 HydroCAD® 10.00 s/n 03363 © 2012 HydroCAD Software Solutions LLC Subcat Reach Pond Link Type II 24-hr 2 YEAR Rainfall=2.87"The Shoppes of Chanhassen Printed 7/24/2014Prepared by Westwood Professional Services, Inc. Page 2HydroCAD® 10.00 s/n 03363 © 2012 HydroCAD Software Solutions LLC Time span=0.00-36.00 hrs, dt=0.05 hrs, 721 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=61,057 sf 36.20% Impervious Runoff Depth=1.63"Subcatchment 1E: Existing Site Tc=15.0 min CN=87 Runoff=2.92 cfs 0.190 af Total Runoff Area = 1.402 ac Runoff Volume = 0.190 af Average Runoff Depth = 1.63" 63.80% Pervious = 0.894 ac 36.20% Impervious = 0.507 ac Type II 24-hr 2 YEAR Rainfall=2.87"The Shoppes of Chanhassen Printed 7/24/2014Prepared by Westwood Professional Services, Inc. Page 3HydroCAD® 10.00 s/n 03363 © 2012 HydroCAD Software Solutions LLC Summary for Subcatchment 1E: Existing Site Runoff =2.92 cfs @ 12.07 hrs, Volume=0.190 af, Depth=1.63" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-36.00 hrs, dt= 0.05 hrs Type II 24-hr 2 YEAR Rainfall=2.87" Area (sf)CN Description 22,105 98Paved parking, HSG D 38,952 80>75% Grass cover, Good, HSG D 61,057 87Weighted Average 38,952 63.80% Pervious Area 22,105 36.20% Impervious Area TcLengthSlopeVelocityCapacityDescription (min)(feet)(ft/ft)(ft/sec)(cfs) 15.0 Direct Entry, Type II 24-hr 10 YEAR Rainfall=4.26"The Shoppes of Chanhassen Printed 7/24/2014Prepared by Westwood Professional Services, Inc. Page 4HydroCAD® 10.00 s/n 03363 © 2012 HydroCAD Software Solutions LLC Time span=0.00-36.00 hrs, dt=0.05 hrs, 721 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=61,057 sf 36.20% Impervious Runoff Depth=2.88"Subcatchment 1E: Existing Site Tc=15.0 min CN=87 Runoff=5.11 cfs 0.336 af Total Runoff Area = 1.402 ac Runoff Volume = 0.336 af Average Runoff Depth = 2.88" 63.80% Pervious = 0.894 ac 36.20% Impervious = 0.507 ac Type II 24-hr 10 YEAR Rainfall=4.26"The Shoppes of Chanhassen Printed 7/24/2014Prepared by Westwood Professional Services, Inc. Page 5HydroCAD® 10.00 s/n 03363 © 2012 HydroCAD Software Solutions LLC Summary for Subcatchment 1E: Existing Site Runoff =5.11 cfs @ 12.07 hrs, Volume=0.336 af, Depth=2.88" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-36.00 hrs, dt= 0.05 hrs Type II 24-hr 10 YEAR Rainfall=4.26" Area (sf)CN Description 22,105 98Paved parking, HSG D 38,952 80>75% Grass cover, Good, HSG D 61,057 87Weighted Average 38,952 63.80% Pervious Area 22,105 36.20% Impervious Area TcLengthSlopeVelocityCapacityDescription (min)(feet)(ft/ft)(ft/sec)(cfs) 15.0 Direct Entry, Type II 24-hr 100 YEAR Rainfall=7.38"The Shoppes of Chanhassen Printed 7/24/2014Prepared by Westwood Professional Services, Inc. Page 6HydroCAD® 10.00 s/n 03363 © 2012 HydroCAD Software Solutions LLC Time span=0.00-36.00 hrs, dt=0.05 hrs, 721 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=61,057 sf 36.20% Impervious Runoff Depth=5.85"Subcatchment 1E: Existing Site Tc=15.0 min CN=87 Runoff=10.05 cfs 0.683 af Total Runoff Area = 1.402 ac Runoff Volume = 0.683 af Average Runoff Depth = 5.85" 63.80% Pervious = 0.894 ac 36.20% Impervious = 0.507 ac Type II 24-hr 100 YEAR Rainfall=7.38"The Shoppes of Chanhassen Printed 7/24/2014Prepared by Westwood Professional Services, Inc. Page 7HydroCAD® 10.00 s/n 03363 © 2012 HydroCAD Software Solutions LLC Summary for Subcatchment 1E: Existing Site Runoff =10.05 cfs @ 12.06 hrs, Volume=0.683 af, Depth=5.85" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-36.00 hrs, dt= 0.05 hrs Type II 24-hr 100 YEAR Rainfall=7.38" Area (sf)CN Description 22,105 98Paved parking, HSG D 38,952 80>75% Grass cover, Good, HSG D 61,057 87Weighted Average 38,952 63.80% Pervious Area 22,105 36.20% Impervious Area TcLengthSlopeVelocityCapacityDescription (min)(feet)(ft/ft)(ft/sec)(cfs) 15.0 Direct Entry, PROPOSED CONDITIONS HYDROLOGY ANALYSIS 1P Proposed Site to Tank 2P Proposed OffSite 3R Proposed Total TANK Underground Storage Routing Diagram for The Shoppes of Chanhassen Prepared by Westwood Professional Services, Inc., Printed 7/24/2014 HydroCAD® 10.00 s/n 03363 © 2012 HydroCAD Software Solutions LLC Subcat Reach Pond Link Type II 24-hr 2 YEAR Rainfall=2.87"The Shoppes of Chanhassen Printed 7/24/2014Prepared by Westwood Professional Services, Inc. Page 2HydroCAD® 10.00 s/n 03363 © 2012 HydroCAD Software Solutions LLC Time span=0.00-36.00 hrs, dt=0.05 hrs, 721 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=30,331 sf 95.55% Impervious Runoff Depth=2.53"Subcatchment 1P: Proposed Site to Tank Tc=10.0 min CN=97 Runoff=2.41 cfs 0.147 af Runoff Area=30,726 sf 84.98% Impervious Runoff Depth=2.32"Subcatchment 2P: Proposed OffSite Tc=10.0 min CN=95 Runoff=2.32 cfs 0.137 af Inflow=2.88 cfs 0.283 afReach 3R: Proposed Total Outflow=2.88 cfs 0.283 af Peak Elev=943.40' Storage=0.046 af Inflow=2.41 cfs 0.147 afPond TANK: Underground Storage Outflow=0.63 cfs 0.147 af Total Runoff Area = 1.402 ac Runoff Volume = 0.283 af Average Runoff Depth = 2.43" 9.77% Pervious = 0.137 ac 90.23% Impervious = 1.265 ac Type II 24-hr 2 YEAR Rainfall=2.87"The Shoppes of Chanhassen Printed 7/24/2014Prepared by Westwood Professional Services, Inc. Page 3HydroCAD® 10.00 s/n 03363 © 2012 HydroCAD Software Solutions LLC Summary for Subcatchment 1P: Proposed Site to Tank Runoff =2.41 cfs @ 12.01 hrs, Volume=0.147 af, Depth=2.53" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-36.00 hrs, dt= 0.05 hrs Type II 24-hr 2 YEAR Rainfall=2.87" Area (sf)CN Description 28,980 98Paved roads w/curbs & sewers, HSG D 1,351 80>75% Grass cover, Good, HSG D 30,331 97Weighted Average 1,351 4.45% Pervious Area 28,980 95.55% Impervious Area TcLengthSlopeVelocityCapacityDescription (min)(feet)(ft/ft)(ft/sec)(cfs) 10.0 Direct Entry, Summary for Subcatchment 2P: Proposed OffSite Runoff =2.32 cfs @ 12.01 hrs, Volume=0.137 af, Depth=2.32" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-36.00 hrs, dt= 0.05 hrs Type II 24-hr 2 YEAR Rainfall=2.87" Area (sf)CN Description 26,110 98Paved roads w/curbs & sewers, HSG D 4,616 80>75% Grass cover, Good, HSG D 30,726 95Weighted Average 4,616 15.02% Pervious Area 26,110 84.98% Impervious Area TcLengthSlopeVelocityCapacityDescription (min)(feet)(ft/ft)(ft/sec)(cfs) 10.0 Direct Entry, Summary for Reach 3R: Proposed Total Inflow Area =1.402 ac,90.23% Impervious, Inflow Depth = 2.43" for 2 YEAR event Inflow =2.88 cfs @ 12.01 hrs, Volume=0.283 af Outflow =2.88 cfs @ 12.01 hrs, Volume=0.283 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind+Trans method, Time Span= 0.00-36.00 hrs, dt= 0.05 hrs Type II 24-hr 2 YEAR Rainfall=2.87"The Shoppes of Chanhassen Printed 7/24/2014Prepared by Westwood Professional Services, Inc. Page 4HydroCAD® 10.00 s/n 03363 © 2012 HydroCAD Software Solutions LLC Summary for Pond TANK: Underground Storage Inflow Area =0.696 ac,95.55% Impervious, Inflow Depth = 2.53" for 2 YEAR event Inflow =2.41 cfs @ 12.01 hrs, Volume=0.147 af Outflow =0.63 cfs @ 12.22 hrs, Volume=0.147 af, Atten= 74%, Lag= 12.5 min Primary=0.63 cfs @ 12.22 hrs, Volume=0.147 af Routing by Stor-Ind method, Time Span= 0.00-36.00 hrs, dt= 0.05 hrs Peak Elev= 943.40' @ 12.22 hrs Surf.Area= 0.041 ac Storage= 0.046 af Plug-Flow detention time= 38.6 min calculated for 0.147 af (100% of inflow) Center-of-Mass det. time= 39.0 min ( 807.9 - 768.9 ) Volume InvertAvail.StorageStorage Description #1A 941.00'0.061 af 30.00'W x 59.40'L x 5.00'H Field A 0.205 af Overall - 0.051 af Embedded = 0.154 af x 40.0% Voids #2A 943.00'0.051 af ADS_StormTech SC-740 x 48 Inside #1 Effective Size= 44.6"W x 30.0"H => 6.45 sf x 7.12'L = 45.9 cf Overall Size= 51.0"W x 30.0"H x 7.56'L with 0.44' Overlap Row Length Adjustment= +0.44' x 6.45 sf x 6 rows 0.112 afTotal Available Storage Storage Group A created with Chamber Wizard DeviceRouting InvertOutlet Devices #1 Primary 941.00'12.0" Round Culvert L= 29.0' RCP, square edge headwall, Ke= 0.500 Inlet / Outlet Invert= 941.00' / 940.50' S= 0.0172 '/' Cc= 0.900 n= 0.013 Concrete pipe, straight & clean, Flow Area= 0.79 sf #2 Device 1 941.00'4.0" Vert. Orifice/Grate C= 0.600 #3 Device 1 944.50'12.0" Round Culvert L= 7.0' RCP, square edge headwall, Ke= 0.500 Inlet / Outlet Invert= 944.50' / 944.38' S= 0.0171 '/' Cc= 0.900 n= 0.013 Concrete pipe, straight & clean, Flow Area= 0.79 sf Primary OutFlow Max=0.63 cfs @ 12.22 hrs HW=943.40' (Free Discharge) 1=Culvert (Passes 0.63 cfs of 5.21 cfs potential flow) 2=Orifice/Grate (Orifice Controls 0.63 cfs @ 7.19 fps) 3=Culvert ( Controls 0.00 cfs) Type II 24-hr 10 YEAR Rainfall=4.26"The Shoppes of Chanhassen Printed 7/24/2014Prepared by Westwood Professional Services, Inc. Page 5HydroCAD® 10.00 s/n 03363 © 2012 HydroCAD Software Solutions LLC Time span=0.00-36.00 hrs, dt=0.05 hrs, 721 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=30,331 sf 95.55% Impervious Runoff Depth=3.91"Subcatchment 1P: Proposed Site to Tank Tc=10.0 min CN=97 Runoff=3.63 cfs 0.227 af Runoff Area=30,726 sf 84.98% Impervious Runoff Depth=3.69"Subcatchment 2P: Proposed OffSite Tc=10.0 min CN=95 Runoff=3.59 cfs 0.217 af Inflow=4.23 cfs 0.444 afReach 3R: Proposed Total Outflow=4.23 cfs 0.444 af Peak Elev=944.34' Storage=0.076 af Inflow=3.63 cfs 0.227 afPond TANK: Underground Storage Outflow=0.75 cfs 0.227 af Total Runoff Area = 1.402 ac Runoff Volume = 0.444 af Average Runoff Depth = 3.80" 9.77% Pervious = 0.137 ac 90.23% Impervious = 1.265 ac Type II 24-hr 10 YEAR Rainfall=4.26"The Shoppes of Chanhassen Printed 7/24/2014Prepared by Westwood Professional Services, Inc. Page 6HydroCAD® 10.00 s/n 03363 © 2012 HydroCAD Software Solutions LLC Summary for Subcatchment 1P: Proposed Site to Tank Runoff =3.63 cfs @ 12.01 hrs, Volume=0.227 af, Depth=3.91" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-36.00 hrs, dt= 0.05 hrs Type II 24-hr 10 YEAR Rainfall=4.26" Area (sf)CN Description 28,980 98Paved roads w/curbs & sewers, HSG D 1,351 80>75% Grass cover, Good, HSG D 30,331 97Weighted Average 1,351 4.45% Pervious Area 28,980 95.55% Impervious Area TcLengthSlopeVelocityCapacityDescription (min)(feet)(ft/ft)(ft/sec)(cfs) 10.0 Direct Entry, Summary for Subcatchment 2P: Proposed OffSite Runoff =3.59 cfs @ 12.01 hrs, Volume=0.217 af, Depth=3.69" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-36.00 hrs, dt= 0.05 hrs Type II 24-hr 10 YEAR Rainfall=4.26" Area (sf)CN Description 26,110 98Paved roads w/curbs & sewers, HSG D 4,616 80>75% Grass cover, Good, HSG D 30,726 95Weighted Average 4,616 15.02% Pervious Area 26,110 84.98% Impervious Area TcLengthSlopeVelocityCapacityDescription (min)(feet)(ft/ft)(ft/sec)(cfs) 10.0 Direct Entry, Summary for Reach 3R: Proposed Total Inflow Area =1.402 ac,90.23% Impervious, Inflow Depth = 3.80" for 10 YEAR event Inflow =4.23 cfs @ 12.01 hrs, Volume=0.444 af Outflow =4.23 cfs @ 12.01 hrs, Volume=0.444 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind+Trans method, Time Span= 0.00-36.00 hrs, dt= 0.05 hrs Type II 24-hr 10 YEAR Rainfall=4.26"The Shoppes of Chanhassen Printed 7/24/2014Prepared by Westwood Professional Services, Inc. Page 7HydroCAD® 10.00 s/n 03363 © 2012 HydroCAD Software Solutions LLC Summary for Pond TANK: Underground Storage Inflow Area =0.696 ac,95.55% Impervious, Inflow Depth = 3.91" for 10 YEAR event Inflow =3.63 cfs @ 12.01 hrs, Volume=0.227 af Outflow =0.75 cfs @ 12.26 hrs, Volume=0.227 af, Atten= 79%, Lag= 14.9 min Primary=0.75 cfs @ 12.26 hrs, Volume=0.227 af Routing by Stor-Ind method, Time Span= 0.00-36.00 hrs, dt= 0.05 hrs Peak Elev= 944.34' @ 12.26 hrs Surf.Area= 0.041 ac Storage= 0.076 af Plug-Flow detention time= 44.3 min calculated for 0.227 af (100% of inflow) Center-of-Mass det. time= 44.6 min ( 803.7 - 759.1 ) Volume InvertAvail.StorageStorage Description #1A 941.00'0.061 af 30.00'W x 59.40'L x 5.00'H Field A 0.205 af Overall - 0.051 af Embedded = 0.154 af x 40.0% Voids #2A 943.00'0.051 af ADS_StormTech SC-740 x 48 Inside #1 Effective Size= 44.6"W x 30.0"H => 6.45 sf x 7.12'L = 45.9 cf Overall Size= 51.0"W x 30.0"H x 7.56'L with 0.44' Overlap Row Length Adjustment= +0.44' x 6.45 sf x 6 rows 0.112 afTotal Available Storage Storage Group A created with Chamber Wizard DeviceRouting InvertOutlet Devices #1 Primary 941.00'12.0" Round Culvert L= 29.0' RCP, square edge headwall, Ke= 0.500 Inlet / Outlet Invert= 941.00' / 940.50' S= 0.0172 '/' Cc= 0.900 n= 0.013 Concrete pipe, straight & clean, Flow Area= 0.79 sf #2 Device 1 941.00'4.0" Vert. Orifice/Grate C= 0.600 #3 Device 1 944.50'12.0" Round Culvert L= 7.0' RCP, square edge headwall, Ke= 0.500 Inlet / Outlet Invert= 944.50' / 944.38' S= 0.0171 '/' Cc= 0.900 n= 0.013 Concrete pipe, straight & clean, Flow Area= 0.79 sf Primary OutFlow Max=0.75 cfs @ 12.26 hrs HW=944.34' (Free Discharge) 1=Culvert (Passes 0.75 cfs of 6.37 cfs potential flow) 2=Orifice/Grate (Orifice Controls 0.75 cfs @ 8.58 fps) 3=Culvert ( Controls 0.00 cfs) Type II 24-hr 100 YEAR Rainfall=7.38"The Shoppes of Chanhassen Printed 7/24/2014Prepared by Westwood Professional Services, Inc. Page 8HydroCAD® 10.00 s/n 03363 © 2012 HydroCAD Software Solutions LLC Time span=0.00-36.00 hrs, dt=0.05 hrs, 721 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=30,331 sf 95.55% Impervious Runoff Depth=7.02"Subcatchment 1P: Proposed Site to Tank Tc=10.0 min CN=97 Runoff=6.36 cfs 0.407 af Runoff Area=30,726 sf 84.98% Impervious Runoff Depth=6.78"Subcatchment 2P: Proposed OffSite Tc=10.0 min CN=95 Runoff=6.38 cfs 0.399 af Inflow=9.44 cfs 0.806 afReach 3R: Proposed Total Outflow=9.44 cfs 0.806 af Peak Elev=945.87' Storage=0.110 af Inflow=6.36 cfs 0.407 afPond TANK: Underground Storage Outflow=4.27 cfs 0.407 af Total Runoff Area = 1.402 ac Runoff Volume = 0.806 af Average Runoff Depth = 6.90" 9.77% Pervious = 0.137 ac 90.23% Impervious = 1.265 ac Type II 24-hr 100 YEAR Rainfall=7.38"The Shoppes of Chanhassen Printed 7/24/2014Prepared by Westwood Professional Services, Inc. Page 9HydroCAD® 10.00 s/n 03363 © 2012 HydroCAD Software Solutions LLC Summary for Subcatchment 1P: Proposed Site to Tank Runoff =6.36 cfs @ 12.01 hrs, Volume=0.407 af, Depth=7.02" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-36.00 hrs, dt= 0.05 hrs Type II 24-hr 100 YEAR Rainfall=7.38" Area (sf)CN Description 28,980 98Paved roads w/curbs & sewers, HSG D 1,351 80>75% Grass cover, Good, HSG D 30,331 97Weighted Average 1,351 4.45% Pervious Area 28,980 95.55% Impervious Area TcLengthSlopeVelocityCapacityDescription (min)(feet)(ft/ft)(ft/sec)(cfs) 10.0 Direct Entry, Summary for Subcatchment 2P: Proposed OffSite Runoff =6.38 cfs @ 12.01 hrs, Volume=0.399 af, Depth=6.78" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-36.00 hrs, dt= 0.05 hrs Type II 24-hr 100 YEAR Rainfall=7.38" Area (sf)CN Description 26,110 98Paved roads w/curbs & sewers, HSG D 4,616 80>75% Grass cover, Good, HSG D 30,726 95Weighted Average 4,616 15.02% Pervious Area 26,110 84.98% Impervious Area TcLengthSlopeVelocityCapacityDescription (min)(feet)(ft/ft)(ft/sec)(cfs) 10.0 Direct Entry, Summary for Reach 3R: Proposed Total Inflow Area =1.402 ac,90.23% Impervious, Inflow Depth = 6.90" for 100 YEAR event Inflow =9.44 cfs @ 12.06 hrs, Volume=0.806 af Outflow =9.44 cfs @ 12.06 hrs, Volume=0.806 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind+Trans method, Time Span= 0.00-36.00 hrs, dt= 0.05 hrs Type II 24-hr 100 YEAR Rainfall=7.38"The Shoppes of Chanhassen Printed 7/24/2014Prepared by Westwood Professional Services, Inc. Page 10HydroCAD® 10.00 s/n 03363 © 2012 HydroCAD Software Solutions LLC Summary for Pond TANK: Underground Storage Inflow Area =0.696 ac,95.55% Impervious, Inflow Depth = 7.02" for 100 YEAR event Inflow =6.36 cfs @ 12.01 hrs, Volume=0.407 af Outflow =4.27 cfs @ 12.11 hrs, Volume=0.407 af, Atten= 33%, Lag= 6.1 min Primary=4.27 cfs @ 12.11 hrs, Volume=0.407 af Routing by Stor-Ind method, Time Span= 0.00-36.00 hrs, dt= 0.05 hrs Peak Elev= 945.87' @ 12.11 hrs Surf.Area= 0.041 ac Storage= 0.110 af Plug-Flow detention time= 38.5 min calculated for 0.407 af (100% of inflow) Center-of-Mass det. time= 38.8 min ( 786.8 - 748.1 ) Volume InvertAvail.StorageStorage Description #1A 941.00'0.061 af 30.00'W x 59.40'L x 5.00'H Field A 0.205 af Overall - 0.051 af Embedded = 0.154 af x 40.0% Voids #2A 943.00'0.051 af ADS_StormTech SC-740 x 48 Inside #1 Effective Size= 44.6"W x 30.0"H => 6.45 sf x 7.12'L = 45.9 cf Overall Size= 51.0"W x 30.0"H x 7.56'L with 0.44' Overlap Row Length Adjustment= +0.44' x 6.45 sf x 6 rows 0.112 afTotal Available Storage Storage Group A created with Chamber Wizard DeviceRouting InvertOutlet Devices #1 Primary 941.00'12.0" Round Culvert L= 29.0' RCP, square edge headwall, Ke= 0.500 Inlet / Outlet Invert= 941.00' / 940.50' S= 0.0172 '/' Cc= 0.900 n= 0.013 Concrete pipe, straight & clean, Flow Area= 0.79 sf #2 Device 1 941.00'4.0" Vert. Orifice/Grate C= 0.600 #3 Device 1 944.50'12.0" Round Culvert L= 7.0' RCP, square edge headwall, Ke= 0.500 Inlet / Outlet Invert= 944.50' / 944.38' S= 0.0171 '/' Cc= 0.900 n= 0.013 Concrete pipe, straight & clean, Flow Area= 0.79 sf Primary OutFlow Max=4.17 cfs @ 12.11 hrs HW=945.84' (Free Discharge) 1=Culvert (Passes 4.17 cfs of 7.88 cfs potential flow) 2=Orifice/Grate (Orifice Controls 0.91 cfs @ 10.41 fps) 3=Culvert (Barrel Controls 3.26 cfs @ 4.15 fps) UNDERGROUND SYSTEM VOLUME CALCULATIONS AND DETAIL Type II 24-hr 100 YEAR Rainfall=7.38"The Shoppes of Chanhassen Printed 7/24/2014Prepared by Westwood Professional Services, Inc. Page 4HydroCAD® 10.00 s/n 03363 © 2012 HydroCAD Software Solutions LLC Stage-Area-Storage for Pond TANK: Underground Storage Elevation (feet) Storage (acre-feet) 941.00 0.000 941.05 0.001 941.10 0.002 941.15 0.002 941.20 0.003 941.25 0.004 941.30 0.005 941.35 0.006 941.40 0.007 941.45 0.007 941.50 0.008 941.55 0.009 941.60 0.010 941.65 0.011 941.70 0.011 941.75 0.012 941.80 0.013 941.85 0.014 941.90 0.015 941.95 0.016 942.00 0.016 942.05 0.017 942.10 0.018 942.15 0.019 942.20 0.020 942.25 0.020 942.30 0.021 942.35 0.022 942.40 0.023 942.45 0.024 942.50 0.025 942.55 0.025 942.60 0.026 942.65 0.027 942.70 0.028 942.75 0.029 942.80 0.029 942.85 0.030 942.90 0.031 942.95 0.032 943.00 0.033 943.05 0.034 943.10 0.036 943.15 0.038 943.20 0.040 943.25 0.041 943.30 0.043 943.35 0.045 943.40 0.046 943.45 0.048 943.50 0.050 943.55 0.051 943.60 0.053 943.65 0.054 Elevation (feet) Storage (acre-feet) 943.70 0.056 943.75 0.058 943.80 0.059 943.85 0.061 943.90 0.063 943.95 0.064 944.00 0.066 944.05 0.067 944.10 0.069 944.15 0.070 944.20 0.072 944.25 0.073 944.30 0.075 944.35 0.076 944.40 0.078 944.45 0.079 944.50 0.081 944.55 0.082 944.60 0.084 944.65 0.085 944.70 0.086 944.75 0.088 944.80 0.089 944.85 0.090 944.90 0.092 944.95 0.093 945.00 0.094 945.05 0.095 945.10 0.097 945.15 0.098 945.20 0.099 945.25 0.100 945.30 0.101 945.35 0.102 945.40 0.103 945.45 0.103 945.50 0.104 945.55 0.105 945.60 0.106 945.65 0.107 945.70 0.108 945.75 0.108 945.80 0.109 945.85 0.110 945.90 0.111 945.95 0.112 946.00 0.112 STORM SEWER SIZING SPREADSHEET Project:The Village Shoppes of Chanhassen Rational Storm Sewer Design Tabulation Westwood Professional Services, Inc. Proj #:220 Plan Date: Frequency Storm (yrs) =10 Comp By:PJD Comp Date: Manning Coefficient =0.013 Checked By:PJD Minimum Pipe Size (in.) =12 7699 Anagram Drive Rainfall Data for Twin Cities Metro Area Only Eden Prairie, MN 55344 Intensity-Duration-Frequency Data Obtained From MNDOT 952-937-5150 FAX 952-937-5822 cover from top pipe Run Description From From To To Area Up Sum Area Time ofPipe TimeSelected Sum Intensity Q = Flow Slope Pipe SelectCapacityFull Velocity Pipe Cover Prefix #Prefix #Inlet (Acres)Area Conc.(min)(min)Tot Tc "C" CXA CXA (IN/HR)Q = CAI %Dia(in.)Dia(in.) of pipe (fps)Length Up M.H. Dn M.H. Up M.H. Dn M.H. Up M.H. Dn M.H. RD 100 STMH 1 0.19 0.19 10.00 0.10 10.00 0.90 0.17 0.17 5.65 0.97 1.00 7.37 12 3.56 4.54 28 951.60 950.30 946.25 945.97 4.18 3.16 STMH 1 STMH 2 0.00 0.19 10.00 0.23 10.10 0.00 0.00 0.17 5.63 0.97 1.00 7.36 12 3.56 4.54 63 950.30 948.60 945.97 945.34 3.16 2.09 RD 200 STMH 2 0.14 0.14 10.00 0.10 10.00 0.90 0.12 0.12 5.65 0.69 1.00 6.47 12 3.56 4.54 28 949.60 948.60 945.00 944.72 3.43 2.71 STMH 2 TANK 300 0.00 0.33 10.00 0.03 10.33 0.00 0.00 0.29 5.57 9.73 1.00 17.49 18 10.50 5.94 9 948.60 948.50 944.32 944.23 2.57 2.56 Invert Elev.Rim Elevation