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Preliminary Storm Water Report 7-3-08
PRELIMINARY STORM WATER REPORT Fairview Chanhassen, MN Prepared for: Pope Associates, Inc. 1255 Energy Park Drive Chanhassen, MN 55108 Prepared by: Westwood Professional Services, Inc. 7699 Anagram Drive Eden Prairie, MN 55344 Phone 952-937-5150, Fax 952-937-5822 July 3, 2008 Project # 20061094.01 H? SUMMARY ??WESTWOOD PROFESSIONAL SERVICES, INC. (952) 937-5150 The attached storm water runoff and ponding calculations are based on Nationwide Urban Runoff Program (NURP) and The Soil Conservation Service Synthetic Unit Hydrograph Method incorporated into the software program HydroCAD Version 8.00; HydroCAD Software Solutions LLC. The goal of this report is to demonstrate that the proposed stormwater management facilities provide rate control and quality control for the storm water from the proposed Fairview project site. The rate control shall not exceed existing discharge rates for the 1, 2, 10 and 100-year storm events as stated in the CODE OF ORDINANCES City of CHANHASSEN, adopted September 24, 2007. The quality control shall obtain a total suspended solids removal of 90% and a phosphorus removal efficiency of 60% or greater using “PONDNET” by William Walker for the storm water contributed by the property. It will also meet the MPCA and NPDES Design Guidelines for Wet Sediment Basins. SITE BACKGROUND The proposed Fairview project site is located in Chanhassen, Minnesota, adjacent and east of Powers Boulevard and south of the intersection with Highway 312. The existing site was recently graded with a temporary pond located in the middle of the property. The undisturbed areas are mostly wooded. Elevations vary greatly throughout the site from 854 to 940. Most of the site, including the pond, drains south discharging 18.19 acres of storm water into a deep ditch located just east of Powers Boulevard. Of the 18.19 acres, 8.73 acres is onsite and the remaining 9.46 acres if offsite. 0.31 acres drain west directly onto Powers Boulevard and into its storm utility infrastructure. 2.45 acres drain north to a culvert that crosses underneath the Highway 312 on-ramp. The remaining 0.40 acres drain east to an existing larger ponding system. (See the attached Existing Drainage Plan in the Appendices). The proposed site land use is medical office which includes a large office building and parking ramp with other associated paved parking areas. 50% of the total area will be made up of impervious surfaces with the total disturbed area being roughly 13 acres. RATE & VOLUME CONTROL The existing site has been modeled assuming Type ‘C’ soils with curve numbers of 72 and 74 for wooded and pasture/prairie, respectively. The post-development curve numbers were obtained from “Technical Release 55: Urban Hydrology for Small Watersheds.” These were 100 for pond surfaces, 98 for impervious surfaces and 74 for areas with 75% or greater grass coverage. (See Appendix for curve numbers and drainage calculations.) A stormwater pond will be located in the southwestern corner of the property. Under the proposed conditions, 20.86 acres, of which 11.40 acres is onsite drainage and 9.46 acres is offsite drainage, will drain south to the proposed pond and ultimately discharge into the ditch located east of Powers Boulevard. 0.17 acres in the northeast corner of the site will drain northeast to a larger ponding system. 0.31 acres will drain west into the Powers Boulevard storm sewer system. (See the attached Proposed Drainage Plan in the Appendices.) The existing runoff discharge rates were compared against the proposed runoff discharge rates and the total site proposed discharge rates are less than the existing rates for the 1-yr, 2-yr, 10-yr and 100-yr storm events. A summary of the existing and proposed drainage flows can be found in the following table. SUMMARY ??WESTWOOD PROFESSIONAL SERVICES, INC. (952) 937-5150 Existing Drainage Proposed Drainage Drainage Flows 1 yr (cfs) 2 yr (cfs) 10 yr (cfs) 100 yr (cfs) 1 yr (cfs) 2 yr (cfs) 10 yr (cfs) 100 yr (cfs) Southwest Drainage to Ditch 6.20 10.08 25.11 47.41 5.00 8.43 24.61 42.37 West Drainage to Powers Blvd 0.26 0.40 0.92 1.66 0.26 0.40 0.92 1.66 East Drainage to Pond system 0.29 0.45 1.05 1.93 0.14 0.22 0.50 0.91 Drainage to Hwy 312 Culvert 1.77 2.77 6.45 11.81 0.00 0.00 0.00 0.00 Total Site Runoff 8.52 13.70 33.53 62.81 5.40 9.05 26.03 44.94 WATER QUALITY The dead storage volumes were determined utilizing 2.5” runoff depth in accordance with NURP design guidelines. The provided dead storage volume can be found in the following table. The Walker Method target dead storage is 1.38 acre-ft. The HydroCAD stage storage data shows that the dead volume provided below the normal water level is 1.38 acre-ft (Refer to the attached Walker Design Spreadsheets and HydroCAD stage storage printout for design basis. Also, See 2.5” frequency NURP Storm volumes in the Appendix.) It should be noted that the water quality pond also provides enough live storage to treat the water quality volume as defined by the MPCA and NPDES program (1/2” of rainfall over new impervious surfaces and fewer than 5.66 cfs per acre of surface area of the pond of discharge). The water quality ponds provide skimming via the submerged outlet to the discharge and are designed such that the 100-Yr 24-Hr storm can pass through the outlet rather than overtopping the pond embankment. One foot of freeboard is provided between the 100-year high water level and the Emergency Overflow Elevation. Two feet of freeboard is provided between the 100-year high water level and the top of the pond embankment. Other pond criteria can also be found in the following table. Drainage Area NWL Dead Storage 100-yr HWL Live Storage 100-yr Inflow 100-yr Discharge Overflow Elevation (ac.) (ft) (ac.-ft) (ft) (ac.-ft) (cfs) (cfs) (ft) Pond 20.86 866.1 1.38 869.6 1.80 88.52 42.37 42.37 870.6 The PONDNET model was used to determine the phosphorus removal efficiency of the proposed ponds. The required removal efficiency for the site is a 60% per the City of Chanhassen CODE OF ORDINANCES. Using typical phosphorus loadings for urban runoff which amount to around 78 lbs/yr for the development, the proposed overall development has a removal efficiency of 70.27%. (See the PondNet model in the Appendix.) EROSION CONTROL Silt fence, riprap, sediment filters at all inlets, seeding, and fiber blanket placement are some of the erosion control measures being proposed. Rock construction entrances are also standard. (See the grading and erosion control plan for additional information.) SUMMARY ??WESTWOOD PROFESSIONAL SERVICES, INC. (952) 937-5150 Appendix Appendix A Existing Conditions Appendix B Proposed Conditions Appendix C Water Quality Appendix D Details SUMMARY ??WESTWOOD PROFESSIONAL SERVICES, INC. (952) 937-5150 APPENDIX A EXISTING CONDITIONS EXDRA-1 Onsite Drainage South to ditch EXDRA-2 Offsite Drainage South to ditch EXDRA-3 Drainage to Hwy 312 Culvert EXDRA-4 West Drainage to Powers Blvd Storm Infrastructure EXDRA-5 East Drainage to ponding system EXDRA-6 Offsite Drainage south to ditch 2L Existing site area 3L Southwest ditch Drainage Diagram for Existing Conditions Prepared by {enter your company name here}, Printed 6/25/2008 HydroCAD® 8.50 s/n 003363 © 2007 HydroCAD Software Solutions LLC Subcat Reach Pond Link Existing Conditions Prepared by {enter your company name here} Printed 6/25/2008 HydroCAD® 8.50 s/n 003363 © 2007 HydroCAD Software Solutions LLC Page 2 Area Listing (all nodes) Area (acres) CN Description (subcatchment-numbers) 9.460 72 Woods/grass comb., Good, HSG C (EXDRA-2,EXDRA-6) 0.710 74 >75% Grass cover, Good, HSG C (EXDRA-4,EXDRA-5) 11.180 74 Pasture/grassland/range, Good, HSG C (EXDRA-1,EXDRA-3) 21.350 TOTAL AREA Existing Conditions Prepared by {enter your company name here} Printed 6/25/2008 HydroCAD® 8.50 s/n 003363 © 2007 HydroCAD Software Solutions LLC Page 3 Soil Listing (all nodes) Area (acres) Soil Goup Subcatchment Numbers 0.000 HSG A 0.000 HSG B 21.350 HSG C EXDRA-1, EXDRA-2, EXDRA-3, EXDRA-4, EXDRA-5, EXDRA-6 0.000 HSG D 0.000 Other 21.350 TOTAL AREA Existing Conditions Type II 24-hr 1-yr Storm Event Rainfall=2.35" Prepared by {enter your company name here} Printed 6/25/2008 HydroCAD® 8.50 s/n 003363 © 2007 HydroCAD Software Solutions LLC Page 4 Time span=5.00-20.00 hrs, dt=0.05 hrs, 301 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method -Pond routing by Stor-Ind method Subcatchment EXDRA-1: Onsite Drainage Runoff Area=8.730 ac 0.00% Impervious Runoff Depth>0.46" Tc=15.0 min CN=74 Runoff=5.17 cfs 0.337 af Subcatchment EXDRA-2: Offsite Drainage Runoff Area=7.620 ac 0.00% Impervious Runoff Depth>0.39" Flow Length=700' Slope=0.0100 '/' Tc=30.2 min CN=72 Runoff=2.29 cfs 0.249 af Subcatchment EXDRA-3: Drainage to Hwy Runoff Area=2.450 ac 0.00% Impervious Runoff Depth>0.46" Tc=10.0 min CN=74 Runoff=1.77 cfs 0.095 af Subcatchment EXDRA-4: West Drainage to Runoff Area=0.310 ac 0.00% Impervious Runoff Depth>0.47" Tc=7.0 min CN=74 Runoff=0.26 cfs 0.012 af Subcatchment EXDRA-5: East Drainage to Runoff Area=0.400 ac 0.00% Impervious Runoff Depth>0.46" Tc=10.0 min CN=74 Runoff=0.29 cfs 0.015 af Subcatchment EXDRA-6: Offsite Drainage Runoff Area=1.840 ac 0.00% Impervious Runoff Depth>0.40" Tc=10.0 min CN=72 Runoff=1.09 cfs 0.061 af Link 2L: Existing site area delayed by 10.0 min Inflow=2.29 cfs 0.249 af Primary=2.28 cfs 0.247 af Link 3L: Southwest ditch Inflow=6.20 cfs 0.645 af Primary=6.20 cfs 0.645 af Total Runoff Area = 21.350 ac Runoff Volume = 0.769 af Average Runoff Depth = 0.43" 100.00% Pervious = 21.350 ac 0.00% Impervious = 0.000 ac Existing Conditions Type II 24-hr 1-yr Storm Event Rainfall=2.35" Prepared by {enter your company name here} Printed 6/25/2008 HydroCAD® 8.50 s/n 003363 © 2007 HydroCAD Software Solutions LLC Page 5 Summary for Subcatchment EXDRA-1: Onsite Drainage South to ditch Runoff = 5.17 cfs @12.09 hrs, Volume= 0.337 af, Depth> 0.46" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type II 24-hr 1-yr Storm Event Rainfall=2.35" Area (ac) CN Description 8.730 74 Pasture/grassland/range, Good, HSG C 8.730 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 15.0 Direct Entry, Summary for Subcatchment EXDRA-2: Offsite Drainage South to ditch Runoff = 2.29 cfs @12.30 hrs, Volume= 0.249 af, Depth> 0.39" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type II 24-hr 1-yr Storm Event Rainfall=2.35" Area (ac) CN Description 7.620 72 Woods/grass comb., Good, HSG C 7.620 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 30.2 700 0.0100 0.39 Lag/CN Method, Summary for Subcatchment EXDRA-3: Drainage to Hwy 312 Culvert Runoff = 1.77 cfs @12.03 hrs, Volume= 0.095 af, Depth> 0.46" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type II 24-hr 1-yr Storm Event Rainfall=2.35" Area (ac) CN Description 2.450 74 Pasture/grassland/range, Good, HSG C 2.450 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Existing Conditions Type II 24-hr 1-yr Storm Event Rainfall=2.35" Prepared by {enter your company name here} Printed 6/25/2008 HydroCAD® 8.50 s/n 003363 © 2007 HydroCAD Software Solutions LLC Page 6 Summary for Subcatchment EXDRA-4: West Drainage to Powers Blvd Storm Infrastructure Runoff = 0.26 cfs @12.00 hrs, Volume= 0.012 af, Depth> 0.47" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type II 24-hr 1-yr Storm Event Rainfall=2.35" Area (ac) CN Description 0.310 74 >75% Grass cover, Good, HSG C 0.310 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.0 Direct Entry, Summary for Subcatchment EXDRA-5: East Drainage to ponding system Runoff = 0.29 cfs @12.03 hrs, Volume= 0.015 af, Depth> 0.46" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type II 24-hr 1-yr Storm Event Rainfall=2.35" Area (ac) CN Description 0.400 74 >75% Grass cover, Good, HSG C 0.400 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Summary for Subcatchment EXDRA-6: Offsite Drainage south to ditch Runoff = 1.09 cfs @12.04 hrs, Volume= 0.061 af, Depth> 0.40" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type II 24-hr 1-yr Storm Event Rainfall=2.35" Area (ac) CN Description 1.840 72 Woods/grass comb., Good, HSG C 1.840 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Existing Conditions Type II 24-hr 1-yr Storm Event Rainfall=2.35" Prepared by {enter your company name here} Printed 6/25/2008 HydroCAD® 8.50 s/n 003363 © 2007 HydroCAD Software Solutions LLC Page 7 Summary for Link 2L: Existing site area Inflow Area = 7.620 ac, 0.00% Impervious, Inflow Depth > 0.39" for 1-yr Storm Event event Inflow = 2.29 cfs @12.30 hrs, Volume= 0.249 af Primary = 2.28 cfs @12.47 hrs, Volume= 0.247 af, Atten= 1%, Lag= 10.0 min Primary outflow = Inflow delayed by 10.0 min, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Summary for Link 3L: Southwest ditch Inflow Area = 18.190 ac, 0.00% Impervious, Inflow Depth > 0.43" for 1-yr Storm Event event Inflow = 6.20 cfs @12.09 hrs, Volume= 0.645 af Primary = 6.20 cfs @12.09 hrs, Volume= 0.645 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Existing Conditions Type II 24-hr 2-yr Storm Event Rainfall=2.80" Prepared by {enter your company name here} Printed 6/25/2008 HydroCAD® 8.50 s/n 003363 © 2007 HydroCAD Software Solutions LLC Page 8 Time span=5.00-20.00 hrs, dt=0.05 hrs, 301 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method -Pond routing by Stor-Ind method Subcatchment EXDRA-1: Onsite Drainage Runoff Area=8.730 ac 0.00% Impervious Runoff Depth>0.70" Tc=15.0 min CN=74 Runoff=8.20 cfs 0.509 af Subcatchment EXDRA-2: Offsite Drainage Runoff Area=7.620 ac 0.00% Impervious Runoff Depth>0.61" Flow Length=700' Slope=0.0100 '/' Tc=30.2 min CN=72 Runoff=3.90 cfs 0.386 af Subcatchment EXDRA-3: Drainage to Hwy Runoff Area=2.450 ac 0.00% Impervious Runoff Depth>0.70" Tc=10.0 min CN=74 Runoff=2.77 cfs 0.143 af Subcatchment EXDRA-4: West Drainage to Runoff Area=0.310 ac 0.00% Impervious Runoff Depth>0.70" Tc=7.0 min CN=74 Runoff=0.40 cfs 0.018 af Subcatchment EXDRA-5: East Drainage to Runoff Area=0.400 ac 0.00% Impervious Runoff Depth>0.70" Tc=10.0 min CN=74 Runoff=0.45 cfs 0.023 af Subcatchment EXDRA-6: Offsite Drainage Runoff Area=1.840 ac 0.00% Impervious Runoff Depth>0.61" Tc=10.0 min CN=72 Runoff=1.79 cfs 0.094 af Link 2L: Existing site area delayed by 10.0 min Inflow=3.90 cfs 0.386 af Primary=3.87 cfs 0.384 af Link 3L: Southwest ditch Inflow=10.08 cfs 0.986 af Primary=10.08 cfs 0.986 af Total Runoff Area = 21.350 ac Runoff Volume = 1.173 af Average Runoff Depth = 0.66" 100.00% Pervious = 21.350 ac 0.00% Impervious = 0.000 ac Existing Conditions Type II 24-hr 2-yr Storm Event Rainfall=2.80" Prepared by {enter your company name here} Printed 6/25/2008 HydroCAD® 8.50 s/n 003363 © 2007 HydroCAD Software Solutions LLC Page 9 Summary for Subcatchment EXDRA-1: Onsite Drainage South to ditch Runoff = 8.20 cfs @12.09 hrs, Volume= 0.509 af, Depth> 0.70" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type II 24-hr 2-yr Storm Event Rainfall=2.80" Area (ac) CN Description 8.730 74 Pasture/grassland/range, Good, HSG C 8.730 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 15.0 Direct Entry, Summary for Subcatchment EXDRA-2: Offsite Drainage South to ditch Runoff = 3.90 cfs @12.28 hrs, Volume= 0.386 af, Depth> 0.61" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type II 24-hr 2-yr Storm Event Rainfall=2.80" Area (ac) CN Description 7.620 72 Woods/grass comb., Good, HSG C 7.620 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 30.2 700 0.0100 0.39 Lag/CN Method, Summary for Subcatchment EXDRA-3: Drainage to Hwy 312 Culvert Runoff = 2.77 cfs @12.03 hrs, Volume= 0.143 af, Depth> 0.70" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type II 24-hr 2-yr Storm Event Rainfall=2.80" Area (ac) CN Description 2.450 74 Pasture/grassland/range, Good, HSG C 2.450 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Existing Conditions Type II 24-hr 2-yr Storm Event Rainfall=2.80" Prepared by {enter your company name here} Printed 6/25/2008 HydroCAD® 8.50 s/n 003363 © 2007 HydroCAD Software Solutions LLC Page 10 Summary for Subcatchment EXDRA-4: West Drainage to Powers Blvd Storm Infrastructure Runoff = 0.40 cfs @11.99 hrs, Volume= 0.018 af, Depth> 0.70" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type II 24-hr 2-yr Storm Event Rainfall=2.80" Area (ac) CN Description 0.310 74 >75% Grass cover, Good, HSG C 0.310 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.0 Direct Entry, Summary for Subcatchment EXDRA-5: East Drainage to ponding system Runoff = 0.45 cfs @12.03 hrs, Volume= 0.023 af, Depth> 0.70" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type II 24-hr 2-yr Storm Event Rainfall=2.80" Area (ac) CN Description 0.400 74 >75% Grass cover, Good, HSG C 0.400 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Summary for Subcatchment EXDRA-6: Offsite Drainage south to ditch Runoff = 1.79 cfs @12.03 hrs, Volume= 0.094 af, Depth> 0.61" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type II 24-hr 2-yr Storm Event Rainfall=2.80" Area (ac) CN Description 1.840 72 Woods/grass comb., Good, HSG C 1.840 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Existing Conditions Type II 24-hr 2-yr Storm Event Rainfall=2.80" Prepared by {enter your company name here} Printed 6/25/2008 HydroCAD® 8.50 s/n 003363 © 2007 HydroCAD Software Solutions LLC Page 11 Summary for Link 2L: Existing site area Inflow Area = 7.620 ac, 0.00% Impervious, Inflow Depth > 0.61" for 2-yr Storm Event event Inflow = 3.90 cfs @12.28 hrs, Volume= 0.386 af Primary = 3.87 cfs @12.45 hrs, Volume= 0.384 af, Atten= 1%, Lag= 10.1 min Primary outflow = Inflow delayed by 10.0 min, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Summary for Link 3L: Southwest ditch Inflow Area = 18.190 ac, 0.00% Impervious, Inflow Depth > 0.65" for 2-yr Storm Event event Inflow = 10.08 cfs @12.08 hrs, Volume= 0.986 af Primary = 10.08 cfs @12.08 hrs, Volume= 0.986 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Existing Conditions Type II 24-hr 10-yr Storm Event Rainfall=4.20" Prepared by {enter your company name here} Printed 6/25/2008 HydroCAD® 8.50 s/n 003363 © 2007 HydroCAD Software Solutions LLC Page 12 Time span=5.00-20.00 hrs, dt=0.05 hrs, 301 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method -Pond routing by Stor-Ind method Subcatchment EXDRA-1: Onsite Drainage Runoff Area=8.730 ac 0.00% Impervious Runoff Depth>1.59" Tc=15.0 min CN=74 Runoff=19.33 cfs 1.154 af Subcatchment EXDRA-2: Offsite Drainage Runoff Area=7.620 ac 0.00% Impervious Runoff Depth>1.44" Flow Length=700' Slope=0.0100 '/' Tc=30.2 min CN=72 Runoff=10.12 cfs 0.915 af Subcatchment EXDRA-3: Drainage to Hwy Runoff Area=2.450 ac 0.00% Impervious Runoff Depth>1.59" Tc=10.0 min CN=74 Runoff=6.45 cfs 0.325 af Subcatchment EXDRA-4: West Drainage to Runoff Area=0.310 ac 0.00% Impervious Runoff Depth>1.59" Tc=7.0 min CN=74 Runoff=0.92 cfs 0.041 af Subcatchment EXDRA-5: East Drainage to Runoff Area=0.400 ac 0.00% Impervious Runoff Depth>1.59" Tc=10.0 min CN=74 Runoff=1.05 cfs 0.053 af Subcatchment EXDRA-6: Offsite Drainage Runoff Area=1.840 ac 0.00% Impervious Runoff Depth>1.45" Tc=10.0 min CN=72 Runoff=4.42 cfs 0.223 af Link 2L: Existing site area delayed by 10.0 min Inflow=10.12 cfs 0.915 af Primary=10.04 cfs 0.911 af Link 3L: Southwest ditch Inflow=25.11 cfs 2.288 af Primary=25.11 cfs 2.288 af Total Runoff Area = 21.350 ac Runoff Volume = 2.711 af Average Runoff Depth = 1.52" 100.00% Pervious = 21.350 ac 0.00% Impervious = 0.000 ac Existing Conditions Type II 24-hr 10-yr Storm Event Rainfall=4.20" Prepared by {enter your company name here} Printed 6/25/2008 HydroCAD® 8.50 s/n 003363 © 2007 HydroCAD Software Solutions LLC Page 13 Summary for Subcatchment EXDRA-1: Onsite Drainage South to ditch Runoff = 19.33 cfs @12.08 hrs, Volume= 1.154 af, Depth> 1.59" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type II 24-hr 10-yr Storm Event Rainfall=4.20" Area (ac) CN Description 8.730 74 Pasture/grassland/range, Good, HSG C 8.730 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 15.0 Direct Entry, Summary for Subcatchment EXDRA-2: Offsite Drainage South to ditch Runoff = 10.12 cfs @12.26 hrs, Volume= 0.915 af, Depth> 1.44" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type II 24-hr 10-yr Storm Event Rainfall=4.20" Area (ac) CN Description 7.620 72 Woods/grass comb., Good, HSG C 7.620 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 30.2 700 0.0100 0.39 Lag/CN Method, Summary for Subcatchment EXDRA-3: Drainage to Hwy 312 Culvert Runoff = 6.45 cfs @12.02 hrs, Volume= 0.325 af, Depth> 1.59" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type II 24-hr 10-yr Storm Event Rainfall=4.20" Area (ac) CN Description 2.450 74 Pasture/grassland/range, Good, HSG C 2.450 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Existing Conditions Type II 24-hr 10-yr Storm Event Rainfall=4.20" Prepared by {enter your company name here} Printed 6/25/2008 HydroCAD® 8.50 s/n 003363 © 2007 HydroCAD Software Solutions LLC Page 14 Summary for Subcatchment EXDRA-4: West Drainage to Powers Blvd Storm Infrastructure Runoff = 0.92 cfs @11.99 hrs, Volume= 0.041 af, Depth> 1.59" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type II 24-hr 10-yr Storm Event Rainfall=4.20" Area (ac) CN Description 0.310 74 >75% Grass cover, Good, HSG C 0.310 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.0 Direct Entry, Summary for Subcatchment EXDRA-5: East Drainage to ponding system Runoff = 1.05 cfs @12.02 hrs, Volume= 0.053 af, Depth> 1.59" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type II 24-hr 10-yr Storm Event Rainfall=4.20" Area (ac) CN Description 0.400 74 >75% Grass cover, Good, HSG C 0.400 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Summary for Subcatchment EXDRA-6: Offsite Drainage south to ditch Runoff = 4.42 cfs @12.02 hrs, Volume= 0.223 af, Depth> 1.45" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type II 24-hr 10-yr Storm Event Rainfall=4.20" Area (ac) CN Description 1.840 72 Woods/grass comb., Good, HSG C 1.840 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Existing Conditions Type II 24-hr 10-yr Storm Event Rainfall=4.20" Prepared by {enter your company name here} Printed 6/25/2008 HydroCAD® 8.50 s/n 003363 © 2007 HydroCAD Software Solutions LLC Page 15 Summary for Link 2L: Existing site area Inflow Area = 7.620 ac, 0.00% Impervious, Inflow Depth > 1.44" for 10-yr Storm Event event Inflow = 10.12 cfs @12.26 hrs, Volume= 0.915 af Primary = 10.04 cfs @12.43 hrs, Volume= 0.911 af, Atten= 1%, Lag= 10.0 min Primary outflow = Inflow delayed by 10.0 min, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Summary for Link 3L: Southwest ditch Inflow Area = 18.190 ac, 0.00% Impervious, Inflow Depth > 1.51" for 10-yr Storm Event event Inflow = 25.11 cfs @12.07 hrs, Volume= 2.288 af Primary = 25.11 cfs @12.07 hrs, Volume= 2.288 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Existing Conditions Type II 24-hr 100-yr Storm Event Rainfall=6.00" Prepared by {enter your company name here} Printed 6/25/2008 HydroCAD® 8.50 s/n 003363 © 2007 HydroCAD Software Solutions LLC Page 16 Time span=5.00-20.00 hrs, dt=0.05 hrs, 301 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method -Pond routing by Stor-Ind method Subcatchment EXDRA-1: Onsite Drainage Runoff Area=8.730 ac 0.00% Impervious Runoff Depth>2.93" Tc=15.0 min CN=74 Runoff=35.70 cfs 2.132 af Subcatchment EXDRA-2: Offsite Drainage Runoff Area=7.620 ac 0.00% Impervious Runoff Depth>2.73" Flow Length=700' Slope=0.0100 '/' Tc=30.2 min CN=72 Runoff=19.53 cfs 1.734 af Subcatchment EXDRA-3: Drainage to Hwy Runoff Area=2.450 ac 0.00% Impervious Runoff Depth>2.94" Tc=10.0 min CN=74 Runoff=11.81 cfs 0.599 af Subcatchment EXDRA-4: West Drainage to Runoff Area=0.310 ac 0.00% Impervious Runoff Depth>2.94" Tc=7.0 min CN=74 Runoff=1.66 cfs 0.076 af Subcatchment EXDRA-5: East Drainage to Runoff Area=0.400 ac 0.00% Impervious Runoff Depth>2.94" Tc=10.0 min CN=74 Runoff=1.93 cfs 0.098 af Subcatchment EXDRA-6: Offsite Drainage Runoff Area=1.840 ac 0.00% Impervious Runoff Depth>2.75" Tc=10.0 min CN=72 Runoff=8.34 cfs 0.422 af Link 2L: Existing site area delayed by 10.0 min Inflow=19.53 cfs 1.734 af Primary=19.41 cfs 1.726 af Link 3L: Southwest ditch Inflow=47.41 cfs 4.280 af Primary=47.41 cfs 4.280 af Total Runoff Area = 21.350 ac Runoff Volume = 5.061 af Average Runoff Depth = 2.84" 100.00% Pervious = 21.350 ac 0.00% Impervious = 0.000 ac Existing Conditions Type II 24-hr 100-yr Storm Event Rainfall=6.00" Prepared by {enter your company name here} Printed 6/25/2008 HydroCAD® 8.50 s/n 003363 © 2007 HydroCAD Software Solutions LLC Page 17 Summary for Subcatchment EXDRA-1: Onsite Drainage South to ditch Runoff = 35.70 cfs @12.07 hrs, Volume= 2.132 af, Depth> 2.93" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type II 24-hr 100-yr Storm Event Rainfall=6.00" Area (ac) CN Description 8.730 74 Pasture/grassland/range, Good, HSG C 8.730 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 15.0 Direct Entry, Summary for Subcatchment EXDRA-2: Offsite Drainage South to ditch Runoff = 19.53 cfs @12.25 hrs, Volume= 1.734 af, Depth> 2.73" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type II 24-hr 100-yr Storm Event Rainfall=6.00" Area (ac) CN Description 7.620 72 Woods/grass comb., Good, HSG C 7.620 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 30.2 700 0.0100 0.39 Lag/CN Method, Summary for Subcatchment EXDRA-3: Drainage to Hwy 312 Culvert Runoff = 11.81 cfs @12.02 hrs, Volume= 0.599 af, Depth> 2.94" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type II 24-hr 100-yr Storm Event Rainfall=6.00" Area (ac) CN Description 2.450 74 Pasture/grassland/range, Good, HSG C 2.450 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Existing Conditions Type II 24-hr 100-yr Storm Event Rainfall=6.00" Prepared by {enter your company name here} Printed 6/25/2008 HydroCAD® 8.50 s/n 003363 © 2007 HydroCAD Software Solutions LLC Page 18 Summary for Subcatchment EXDRA-4: West Drainage to Powers Blvd Storm Infrastructure Runoff = 1.66 cfs @11.98 hrs, Volume= 0.076 af, Depth> 2.94" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type II 24-hr 100-yr Storm Event Rainfall=6.00" Area (ac) CN Description 0.310 74 >75% Grass cover, Good, HSG C 0.310 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.0 Direct Entry, Summary for Subcatchment EXDRA-5: East Drainage to ponding system Runoff = 1.93 cfs @12.02 hrs, Volume= 0.098 af, Depth> 2.94" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type II 24-hr 100-yr Storm Event Rainfall=6.00" Area (ac) CN Description 0.400 74 >75% Grass cover, Good, HSG C 0.400 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Summary for Subcatchment EXDRA-6: Offsite Drainage south to ditch Runoff = 8.34 cfs @12.02 hrs, Volume= 0.422 af, Depth> 2.75" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type II 24-hr 100-yr Storm Event Rainfall=6.00" Area (ac) CN Description 1.840 72 Woods/grass comb., Good, HSG C 1.840 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Existing Conditions Type II 24-hr 100-yr Storm Event Rainfall=6.00" Prepared by {enter your company name here} Printed 6/25/2008 HydroCAD® 8.50 s/n 003363 © 2007 HydroCAD Software Solutions LLC Page 19 Summary for Link 2L: Existing site area Inflow Area = 7.620 ac, 0.00% Impervious, Inflow Depth > 2.73" for 100-yr Storm Event event Inflow = 19.53 cfs @12.25 hrs, Volume= 1.734 af Primary = 19.41 cfs @12.42 hrs, Volume= 1.726 af, Atten= 1%, Lag= 10.0 min Primary outflow = Inflow delayed by 10.0 min, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Summary for Link 3L: Southwest ditch Inflow Area = 18.190 ac, 0.00% Impervious, Inflow Depth > 2.82" for 100-yr Storm Event event Inflow = 47.41 cfs @12.07 hrs, Volume= 4.280 af Primary = 47.41 cfs @12.07 hrs, Volume= 4.280 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs SUMMARY ??WESTWOOD PROFESSIONAL SERVICES, INC. (952) 937-5150 APPENDIX B PROPOSED CONDITIONS DRA-1 Onsite Southern Drainage DRA-2 Offsite Southern Drainage DRA-3 East Drainage to ponding system DRA-4 Western Drainage to Powers Infrastructure DRA-6 Offsite Southern Drainage Pond Pond to ditch 1L Site Infrastructure Drainage Diagram for Proposed Conditions Prepared by {enter your company name here}, Printed 6/25/2008 HydroCAD® 8.50 s/n 003363 © 2007 HydroCAD Software Solutions LLC Subcat Reach Pond Link Proposed Conditions Prepared by {enter your company name here} Printed 6/25/2008 HydroCAD® 8.50 s/n 003363 © 2007 HydroCAD Software Solutions LLC Page 2 Area Listing (all nodes) Area (acres) CN Description (subcatchment-numbers) 9.460 72 Woods/grass comb., Good, HSG C (DRA-2,DRA-6) 4.700 74 >75% Grass cover, Good, HSG C (DRA-1,DRA-3,DRA-4) 6.680 98 Paved parking & roofs (DRA-1) 0.500 100 Pond NWL (DRA-1) 21.340 TOTAL AREA Proposed Conditions Prepared by {enter your company name here} Printed 6/25/2008 HydroCAD® 8.50 s/n 003363 © 2007 HydroCAD Software Solutions LLC Page 3 Soil Listing (all nodes) Area (acres) Soil Goup Subcatchment Numbers 0.000 HSG A 0.000 HSG B 14.160 HSG C DRA-1, DRA-2, DRA-3, DRA-4, DRA-6 0.000 HSG D 7.180 Other DRA-1 21.340 TOTAL AREA Proposed Conditions Type II 24-hr 1-yr Storm Event Rainfall=2.35" Prepared by {enter your company name here} Printed 6/25/2008 HydroCAD® 8.50 s/n 003363 © 2007 HydroCAD Software Solutions LLC Page 4 Time span=0.00-24.00 hrs, dt=0.05 hrs, 481 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method -Pond routing by Stor-Ind method Subcatchment DRA-1: Onsite Southern Runoff Area=11.400 ac 62.98% Impervious Runoff Depth>1.32" Tc=10.0 min CN=89 Runoff=22.79 cfs 1.255 af Subcatchment DRA-2: Offsite Southern Runoff Area=7.620 ac 0.00% Impervious Runoff Depth>0.45" Flow Length=700' Slope=0.0100 '/' Tc=30.2 min CN=72 Runoff=2.29 cfs 0.284 af Subcatchment DRA-3: East Drainage to Runoff Area=0.170 ac 0.00% Impervious Runoff Depth>0.52" Tc=7.0 min CN=74 Runoff=0.14 cfs 0.007 af Subcatchment DRA-4: Western Drainage to Runoff Area=0.310 ac 0.00% Impervious Runoff Depth>0.52" Tc=7.0 min CN=74 Runoff=0.26 cfs 0.014 af Subcatchment DRA-6: Offsite Southern Runoff Area=1.840 ac 0.00% Impervious Runoff Runoff Depth>0.45" Tc=10.0 min CN=72 Runoff=1.09 cfs 0.069 af Pond Pond: Pond to ditch Peak Elev=867.44' Storage=87,033 cf Inflow=23.87 cfs 1.607 af Outflow=5.00 cfs 1.385 af Link 1L: Site Infrastructure delayed by 10.0 min Inflow=2.29 cfs 0.284 af Primary=2.28 cfs 0.282 af Total Runoff Area = 21.340 ac Runoff Volume = 1.629 af Average Runoff Depth = 0.92" 66.35% Pervious = 14.160 ac 33.65% Impervious = 7.180 ac Proposed Conditions Type II 24-hr 1-yr Storm Event Rainfall=2.35" Prepared by {enter your company name here} Printed 6/25/2008 HydroCAD® 8.50 s/n 003363 © 2007 HydroCAD Software Solutions LLC Page 5 Summary for Subcatchment DRA-1: Onsite Southern Drainage Runoff = 22.79 cfs @12.01 hrs, Volume= 1.255 af, Depth> 1.32" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type II 24-hr 1-yr Storm Event Rainfall=2.35" Area (ac) CN Description * 0.500 100 Pond NWL 6.680 98 Paved parking & roofs 4.220 74 >75% Grass cover, Good, HSG C 11.400 89 Weighted Average 4.220 Pervious Area 7.180 Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Summary for Subcatchment DRA-2: Offsite Southern Drainage Runoff = 2.29 cfs @12.30 hrs, Volume= 0.284 af, Depth> 0.45" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type II 24-hr 1-yr Storm Event Rainfall=2.35" Area (ac) CN Description 7.620 72 Woods/grass comb., Good, HSG C 7.620 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 30.2 700 0.0100 0.39 Lag/CN Method, Summary for Subcatchment DRA-3: East Drainage to ponding system Runoff = 0.14 cfs @12.00 hrs, Volume= 0.007 af, Depth> 0.52" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type II 24-hr 1-yr Storm Event Rainfall=2.35" Area (ac) CN Description 0.170 74 >75% Grass cover, Good, HSG C 0.170 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.0 Direct Entry, Proposed Conditions Type II 24-hr 1-yr Storm Event Rainfall=2.35" Prepared by {enter your company name here} Printed 6/25/2008 HydroCAD® 8.50 s/n 003363 © 2007 HydroCAD Software Solutions LLC Page 6 Summary for Subcatchment DRA-4: Western Drainage to Powers Infrastructure Runoff = 0.26 cfs @12.00 hrs, Volume= 0.014 af, Depth> 0.52" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type II 24-hr 1-yr Storm Event Rainfall=2.35" Area (ac) CN Description 0.310 74 >75% Grass cover, Good, HSG C 0.310 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.0 Direct Entry, Summary for Subcatchment DRA-6: Offsite Southern Drainage Runoff = 1.09 cfs @12.04 hrs, Volume= 0.069 af, Depth> 0.45" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type II 24-hr 1-yr Storm Event Rainfall=2.35" Area (ac) CN Description 1.840 72 Woods/grass comb., Good, HSG C 1.840 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Summary for Pond Pond: Pond to ditch Inflow Area = 20.860 ac, 34.42% Impervious, Inflow Depth > 0.92" for 1-yr Storm Event event Inflow = 23.87 cfs @12.02 hrs, Volume= 1.607 af Outflow = 5.00 cfs @12.50 hrs, Volume= 1.385 af, Atten= 79%, Lag= 29.3 min Primary = 5.00 cfs @12.50 hrs, Volume= 1.385 af Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Starting Elev= 866.10' Surf.Area= 18,748 sf Storage= 60,034 cf Peak Elev= 867.44' @12.50 hrs Surf.Area= 21,670 sf Storage= 87,033 cf (27,000 cf above start) Plug-Flow detention time= 918.0 min calculated for 0.007 af (0% of inflow) Center-of-Mass det. time= 83.9 min ( 926.1 -842.2 ) Volume Invert Avail.Storage Storage Description #1 856.10' 243,941 cf Custom Stage Data (Prismatic) Listed below (Recalc) Proposed Conditions Type II 24-hr 1-yr Storm Event Rainfall=2.35" Prepared by {enter your company name here} Printed 6/25/2008 HydroCAD® 8.50 s/n 003363 © 2007 HydroCAD Software Solutions LLC Page 7 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 856.10 11 0 0 858.00 969 931 931 860.00 3,477 4,446 5,377 862.00 6,568 10,045 15,422 864.00 10,029 16,597 32,019 865.00 11,872 10,951 42,969 866.00 18,529 15,201 58,170 868.00 22,903 41,432 99,602 870.00 27,564 50,467 150,069 872.00 32,509 60,073 210,142 873.00 35,089 33,799 243,941 Device Routing Invert Outlet Devices #1 Primary 866.00' 33.0" x 100.0' long Culvert RCP, square edge headwall, Ke= 0.500 Outlet Invert= 865.00' S= 0.0100 '/' Cc= 0.900 n= 0.013 #2 Device 1 866.10' Custom Weir/Orifice, C= 2.62 Head (feet) 0.00 3.25 3.25 6.00 Width (feet) 0.00 6.00 6.00 6.00 Primary OutFlow Max=4.99 cfs @12.50 hrs HW=867.44' (Free Discharge) 1=Culvert (Passes 4.99 cfs of 12.70 cfs potential flow) 2=Custom Weir/Orifice (Weir Controls 4.99 cfs @3.03 fps) Summary for Link 1L: Site Infrastructure Inflow Area = 7.620 ac, 0.00% Impervious, Inflow Depth > 0.45" for 1-yr Storm Event event Inflow = 2.29 cfs @12.30 hrs, Volume= 0.284 af Primary = 2.28 cfs @12.47 hrs, Volume= 0.282 af, Atten= 1%, Lag= 10.0 min Primary outflow = Inflow delayed by 10.0 min, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Proposed Conditions Type II 24-hr 2-yr Storm Event Rainfall=2.80" Prepared by {enter your company name here} Printed 6/25/2008 HydroCAD® 8.50 s/n 003363 © 2007 HydroCAD Software Solutions LLC Page 8 Time span=0.00-24.00 hrs, dt=0.05 hrs, 481 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method -Pond routing by Stor-Ind method Subcatchment DRA-1: Onsite Southern Runoff Area=11.400 ac 62.98% Impervious Runoff Depth>1.72" Tc=10.0 min CN=89 Runoff=29.41 cfs 1.631 af Subcatchment DRA-2: Offsite Southern Runoff Area=7.620 ac 0.00% Impervious Runoff Depth>0.68" Flow Length=700' Slope=0.0100 '/' Tc=30.2 min CN=72 Runoff=3.90 cfs 0.434 af Subcatchment DRA-3: East Drainage to Runoff Area=0.170 ac 0.00% Impervious Runoff Depth>0.78" Tc=7.0 min CN=74 Runoff=0.22 cfs 0.011 af Subcatchment DRA-4: Western Drainage to Runoff Area=0.310 ac 0.00% Impervious Runoff Depth>0.78" Tc=7.0 min CN=74 Runoff=0.40 cfs 0.020 af Subcatchment DRA-6: Offsite Southern Runoff Area=1.840 ac 0.00% Impervious Runoff Runoff Depth>0.69" Tc=10.0 min CN=72 Runoff=1.79 cfs 0.106 af Pond Pond: Pond to ditch Peak Elev=867.75' Storage=93,870 cf Inflow=31.32 cfs 2.169 af Outflow=8.43 cfs 1.926 af Link 1L: Site Infrastructure delayed by 10.0 min Inflow=3.90 cfs 0.434 af Primary=3.87 cfs 0.432 af Total Runoff Area = 21.340 ac Runoff Volume = 2.202 af Average Runoff Depth = 1.24" 66.35% Pervious = 14.160 ac 33.65% Impervious = 7.180 ac Proposed Conditions Type II 24-hr 2-yr Storm Event Rainfall=2.80" Prepared by {enter your company name here} Printed 6/25/2008 HydroCAD® 8.50 s/n 003363 © 2007 HydroCAD Software Solutions LLC Page 9 Summary for Subcatchment DRA-1: Onsite Southern Drainage Runoff = 29.41 cfs @12.01 hrs, Volume= 1.631 af, Depth> 1.72" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type II 24-hr 2-yr Storm Event Rainfall=2.80" Area (ac) CN Description * 0.500 100 Pond NWL 6.680 98 Paved parking & roofs 4.220 74 >75% Grass cover, Good, HSG C 11.400 89 Weighted Average 4.220 Pervious Area 7.180 Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Summary for Subcatchment DRA-2: Offsite Southern Drainage Runoff = 3.90 cfs @12.28 hrs, Volume= 0.434 af, Depth> 0.68" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type II 24-hr 2-yr Storm Event Rainfall=2.80" Area (ac) CN Description 7.620 72 Woods/grass comb., Good, HSG C 7.620 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 30.2 700 0.0100 0.39 Lag/CN Method, Summary for Subcatchment DRA-3: East Drainage to ponding system Runoff = 0.22 cfs @11.99 hrs, Volume= 0.011 af, Depth> 0.78" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type II 24-hr 2-yr Storm Event Rainfall=2.80" Area (ac) CN Description 0.170 74 >75% Grass cover, Good, HSG C 0.170 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.0 Direct Entry, Proposed Conditions Type II 24-hr 2-yr Storm Event Rainfall=2.80" Prepared by {enter your company name here} Printed 6/25/2008 HydroCAD® 8.50 s/n 003363 © 2007 HydroCAD Software Solutions LLC Page 10 Summary for Subcatchment DRA-4: Western Drainage to Powers Infrastructure Runoff = 0.40 cfs @11.99 hrs, Volume= 0.020 af, Depth> 0.78" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type II 24-hr 2-yr Storm Event Rainfall=2.80" Area (ac) CN Description 0.310 74 >75% Grass cover, Good, HSG C 0.310 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.0 Direct Entry, Summary for Subcatchment DRA-6: Offsite Southern Drainage Runoff = 1.79 cfs @12.03 hrs, Volume= 0.106 af, Depth> 0.69" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type II 24-hr 2-yr Storm Event Rainfall=2.80" Area (ac) CN Description 1.840 72 Woods/grass comb., Good, HSG C 1.840 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Summary for Pond Pond: Pond to ditch Inflow Area = 20.860 ac, 34.42% Impervious, Inflow Depth > 1.25" for 2-yr Storm Event event Inflow = 31.32 cfs @12.02 hrs, Volume= 2.169 af Outflow = 8.43 cfs @12.32 hrs, Volume= 1.926 af, Atten= 73%, Lag= 18.2 min Primary = 8.43 cfs @12.32 hrs, Volume= 1.926 af Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Starting Elev= 866.10' Surf.Area= 18,748 sf Storage= 60,034 cf Peak Elev= 867.75' @12.32 hrs Surf.Area= 22,349 sf Storage= 93,870 cf (33,837 cf above start) Plug-Flow detention time= 478.4 min calculated for 0.548 af (25% of inflow) Center-of-Mass det. time= 71.6 min ( 907.1 -835.4 ) Volume Invert Avail.Storage Storage Description #1 856.10' 243,941 cf Custom Stage Data (Prismatic) Listed below (Recalc) Proposed Conditions Type II 24-hr 2-yr Storm Event Rainfall=2.80" Prepared by {enter your company name here} Printed 6/25/2008 HydroCAD® 8.50 s/n 003363 © 2007 HydroCAD Software Solutions LLC Page 11 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 856.10 11 0 0 858.00 969 931 931 860.00 3,477 4,446 5,377 862.00 6,568 10,045 15,422 864.00 10,029 16,597 32,019 865.00 11,872 10,951 42,969 866.00 18,529 15,201 58,170 868.00 22,903 41,432 99,602 870.00 27,564 50,467 150,069 872.00 32,509 60,073 210,142 873.00 35,089 33,799 243,941 Device Routing Invert Outlet Devices #1 Primary 866.00' 33.0" x 100.0' long Culvert RCP, square edge headwall, Ke= 0.500 Outlet Invert= 865.00' S= 0.0100 '/' Cc= 0.900 n= 0.013 #2 Device 1 866.10' Custom Weir/Orifice, C= 2.62 Head (feet) 0.00 3.25 3.25 6.00 Width (feet) 0.00 6.00 6.00 6.00 Primary OutFlow Max=8.41 cfs @12.32 hrs HW=867.75' (Free Discharge) 1=Culvert (Passes 8.41 cfs of 17.51 cfs potential flow) 2=Custom Weir/Orifice (Weir Controls 8.41 cfs @3.36 fps) Summary for Link 1L: Site Infrastructure Inflow Area = 7.620 ac, 0.00% Impervious, Inflow Depth > 0.68" for 2-yr Storm Event event Inflow = 3.90 cfs @12.28 hrs, Volume= 0.434 af Primary = 3.87 cfs @12.45 hrs, Volume= 0.432 af, Atten= 1%, Lag= 10.1 min Primary outflow = Inflow delayed by 10.0 min, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Proposed Conditions Type II 24-hr 10-yr Storm Event Rainfall=4.20" Prepared by {enter your company name here} Printed 6/25/2008 HydroCAD® 8.50 s/n 003363 © 2007 HydroCAD Software Solutions LLC Page 12 Time span=0.00-24.00 hrs, dt=0.05 hrs, 481 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method -Pond routing by Stor-Ind method Subcatchment DRA-1: Onsite Southern Runoff Area=11.400 ac 62.98% Impervious Runoff Depth>3.01" Tc=10.0 min CN=89 Runoff=50.32 cfs 2.855 af Subcatchment DRA-2: Offsite Southern Runoff Area=7.620 ac 0.00% Impervious Runoff Depth>1.59" Flow Length=700' Slope=0.0100 '/' Tc=30.2 min CN=72 Runoff=10.12 cfs 1.008 af Subcatchment DRA-3: East Drainage to Runoff Area=0.170 ac 0.00% Impervious Runoff Depth>1.74" Tc=7.0 min CN=74 Runoff=0.50 cfs 0.025 af Subcatchment DRA-4: Western Drainage to Runoff Area=0.310 ac 0.00% Impervious Runoff Depth>1.74" Tc=7.0 min CN=74 Runoff=0.92 cfs 0.045 af Subcatchment DRA-6: Offsite Southern Runoff Area=1.840 ac 0.00% Impervious Runoff Depth>1.60" Tc=10.0 min CN=72 Runoff=4.42 cfs 0.245 af Pond Pond: Pond to ditch Peak Elev=868.63' Storage=114,468 cf Inflow=55.91 cfs 4.104 af Outflow=24.61 cfs 3.806 af Link 1L: Site Infrastructure delayed by 10.0 min Inflow=10.12 cfs 1.008 af Primary=10.04 cfs 1.004 af Total Runoff Area = 21.340 ac Runoff Volume = 4.178 af Average Runoff Depth = 2.35" 66.35% Pervious = 14.160 ac 33.65% Impervious = 7.180 ac Proposed Conditions Type II 24-hr 10-yr Storm Event Rainfall=4.20" Prepared by {enter your company name here} Printed 6/25/2008 HydroCAD® 8.50 s/n 003363 © 2007 HydroCAD Software Solutions LLC Page 13 Summary for Subcatchment DRA-1: Onsite Southern Drainage Runoff = 50.32 cfs @12.01 hrs, Volume= 2.855 af, Depth> 3.01" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type II 24-hr 10-yr Storm Event Rainfall=4.20" Area (ac) CN Description * 0.500 100 Pond NWL 6.680 98 Paved parking & roofs 4.220 74 >75% Grass cover, Good, HSG C 11.400 89 Weighted Average 4.220 Pervious Area 7.180 Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Summary for Subcatchment DRA-2: Offsite Southern Drainage Runoff = 10.12 cfs @12.26 hrs, Volume= 1.008 af, Depth> 1.59" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type II 24-hr 10-yr Storm Event Rainfall=4.20" Area (ac) CN Description 7.620 72 Woods/grass comb., Good, HSG C 7.620 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 30.2 700 0.0100 0.39 Lag/CN Method, Summary for Subcatchment DRA-3: East Drainage to ponding system Runoff = 0.50 cfs @11.99 hrs, Volume= 0.025 af, Depth> 1.74" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type II 24-hr 10-yr Storm Event Rainfall=4.20" Area (ac) CN Description 0.170 74 >75% Grass cover, Good, HSG C 0.170 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.0 Direct Entry, Proposed Conditions Type II 24-hr 10-yr Storm Event Rainfall=4.20" Prepared by {enter your company name here} Printed 6/25/2008 HydroCAD® 8.50 s/n 003363 © 2007 HydroCAD Software Solutions LLC Page 14 Summary for Subcatchment DRA-4: Western Drainage to Powers Infrastructure Runoff = 0.92 cfs @11.99 hrs, Volume= 0.045 af, Depth> 1.74" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type II 24-hr 10-yr Storm Event Rainfall=4.20" Area (ac) CN Description 0.310 74 >75% Grass cover, Good, HSG C 0.310 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.0 Direct Entry, Summary for Subcatchment DRA-6: Offsite Southern Drainage Runoff = 4.42 cfs @12.02 hrs, Volume= 0.245 af, Depth> 1.60" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type II 24-hr 10-yr Storm Event Rainfall=4.20" Area (ac) CN Description 1.840 72 Woods/grass comb., Good, HSG C 1.840 Pervious Area Tc Length Slope Velocity Capacity Description (min) ((feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Summary for Pond Pond: Pond to ditch Inflow Area = 20.860 ac, 34.42% Impervious, Inflow Depth > 2.36" for 10-yr Storm Event event Inflow = 55.91 cfs @12.01 hrs, Volume= 4.104 af Outflow = 24.61 cfs @12.17 hrs, Volume= 3.806 af, Atten= 56%, Lag= 9.5 min Primary = 24.61 cfs @12.17 hrs, Volume= 3.806 af Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Starting Elev= 866.10' Surf.Area= 18,748 sf Storage= 60,034 cf Peak Elev= 868.63' @12.17 hrs Surf.Area= 24,369 sf Storage= 114,468 cf (54,434 cf above start) Plug-Flow detention time= 244.6 min calculated for 2.427 af (59% of inflow) Center-of-Mass det. time= 52.3 min ( 873.3 -821.0 ) Volume Invert Avail.Storage Storage Description #1 856.10' 243,941 cf Custom Stage Data (Prismatic) Listed below (Recalc) Proposed Conditions Type II 24-hr 10-yr Storm Event Rainfall=4.20" Prepared by {enter your company name here} Printed 6/25/2008 HydroCAD® 8.50 s/n 003363 © 2007 HydroCAD Software Solutions LLC Page 15 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 856.10 11 0 0 858.00 969 931 931 860.00 3,477 4,446 5,377 862.00 6,568 10,045 15,422 864.00 10,029 16,597 32,019 865.00 11,872 10,951 42,969 866.00 18,529 15,201 58,170 868.00 22,903 41,432 99,602 870.00 27,564 50,467 150,069 872.00 32,509 60,073 210,142 873.00 35,089 33,799 243,941 Device Routing Invert Outlet Devices #1 Primary 866.00' 33.0" x 100.0' long Culvert RCP, square edge headwall, Ke= 0.500 Outlet Invert= 865.00' S= 0.0100 '/' Cc= 0.900 n= 0.013 #2 Device 1 866.10' Custom Weir/Orifice, C= 2.62 Head (feet) 0.00 3.25 3.25 6.00 Width (feet) 0.00 6.00 6.00 6.00 Primary OutFlow Max=24.37 cfs @12.17 hrs HW=868.62' (Free Discharge) 1=Culvert (Passes 24.37 cfs of 32.01 cfs potential flow) 2=Custom Weir/Orifice (Weir Controls 24.37 cfs @4.16 fps) Summary for Link 1L: Site Infrastructure Inflow Area = 7.620 ac, 0.00% Impervious, Inflow Depth > 1.59" for 10-yr Storm Event event Inflow = 10.12 cfs @12.26 hrs, Volume= 1.008 af Primary = 10.04 cfs @12.43 hrs, Volume= 1.004 af, Atten= 1%, Lag= 10.0 min Primary outflow = Inflow delayed by 10.0 min, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Proposed Conditions Type II 24-hr 100-yr Storm Event Rainfall=6.00" Prepared by {enter your company name here} Printed 6/25/2008 HydroCAD® 8.50 s/n 003363 © 2007 HydroCAD Software Solutions LLC Page 16 Time span=0.00-24.00 hrs, dt=0.05 hrs, 481 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method -Pond routing by Stor-Ind method Subcatchment DRA-1: Onsite Southern Runoff Area=11.400 ac 62.98% Impervious Runoff Depth>4.73" Tc=10.0 min CN=89 Runoff=77.18 cfs 4.491 af Subcatchment DRA-2: Offsite Southern Runoff Area=7.620 ac 0.00% Impervious Runoff Depth>2.97" Flow Length=700' Slope=0.0100 '/' Tc=30.2 min CN=72 Runoff=19.53 cfs 1.885 af Subcatchment DRA-3: East Drainage to Runoff Area=0.170 ac 0.00% Impervious Runoff Depth>3.18" Tc=7.0 min CN=74 Runoff=0.91 cfs 0.045 af Subcatchment DRA-4: Western Drainage to Runoff Area=0.310 ac 0.00% Impervious Runoff Depth>3.18" Tc=7.0 min CN=74 Runoff=1.66 cfs 0.082 af Subcatchment DRA-6: Offsite Southern Runoff Area=1.840 ac 0.00% Impervious Runoff Depth>2.99" Tc=10.0 min CN=72 Runoff=8.34 cfs 0.458 af Pond Pond: Pond to ditch Peak Elev=869.57' Storage=138,458 cf Inflow=88.52 cfs 6.828 af Outflow=42.37 cfs 6.473 af Link 1L: Site Infrastructure delayed by 10.0 min Inflow=19.53 cfs 1.885 af Primary=19.41 cfs 1.880 af Total Runoff Area = 21.340 ac Runoff Volume = 6.961 af Average Runoff Depth = 3.91" 66.35% Pervious = 14.160 ac 33.65% Impervious = 7.180 ac Proposed Conditions Type II 24-hr 100-yr Storm Event Rainfall=6.00" Prepared by {enter your company name here} Printed 6/25/2008 HydroCAD® 8.50 s/n 003363 © 2007 HydroCAD Software Solutions LLC Page 17 Summary for Subcatchment DRA-1: Onsite Southern Drainage Runoff = 77.18 cfs @12.01 hrs, Volume= 4.491 af, Depth> 4.73" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type II 24-hr 100-yr Storm Event Rainfall=6.00" Area (ac) CN Description * 0.500 100 Pond NWL 6.680 98 Paved parking & roofs 4.220 74 >75% Grass cover, Good, HSG C 11.400 89 Weighted Average 4.220 Pervious Area 7.180 Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Summary for Subcatchment DRA-2: Offsite Southern Drainage Runoff = 19.53 cfs @12.25 hrs, Volume= 1.885 af, Depth> 2.97" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type II 24-hr 100-yr Storm Event Rainfall=6.00" Area (ac) CN Description 7.620 72 Woods/grass comb., Good, HSG C 7.620 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 30.2 700 0.0100 0.39 Lag/CN Method, Summary for Subcatchment DRA-3: East Drainage to ponding system Runoff = 0.91 cfs @11.98 hrs, Volume= 0.045 af, Depth> 3.18" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type II 24-hr 100-yr Storm Event Rainfall=6.00" Area (ac) CN Description 0.170 74 >75% Grass cover, Good, HSG C 0.170 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.0 Direct Entry, Proposed Conditions Type II 24-hr 100-yr Storm Event Rainfall=6.00" Prepared by {enter your company name here} Printed 6/25/2008 HydroCAD® 8.50 s/n 003363 © 2007 HydroCAD Software Solutions LLC Page 18 Summary for Subcatchment DRA-4: Western Drainage to Powers Infrastructure Runoff = 1.66 cfs @11.98 hrs, Volume= 0.082 af, Depth> 3.18" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type II 24-hr 100-yr Storm Event Rainfall=6.00" Area (ac) CN Description 0.310 74 >75% Grass cover, Good, HSG C 0.310 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.0 Direct Entry, Summary for Subcatchment DRA-6: Offsite Southern Drainage Runoff = 8.34 cfs @12.02 hrs, Volume= 0.458 af, Depth> 2.99" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type II 24-hr 100-yr Storm Event Rainfall=6.00" Area (ac) CN Description 1.840 72 Woods/grass comb., Good, HSG C 1.840 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Summary for Pond Pond: Pond to ditch Inflow Area = 20.860 ac, 34.42% Impervious, Inflow Depth > 3.93" for 100-yr Storm Event event Inflow = 88.52 cfs @12.01 hrs, Volume= 6.828 af Outflow = 42.37 cfs @12.16 hrs, Volume= 6.473 af, Atten= 52%, Lag= 9.1 min Primary = 42.37 cfs @12.16 hrs, Volume= 6.473 af Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Starting Elev= 866.10' Surf.Area= 18,748 sf Storage= 60,034 cf Peak Elev= 869.57' @12.16 hrs Surf.Area= 26,564 sf Storage= 138,458 cf (78,424 cf above start) Plug-Flow detention time= 173.4 min calculated for 5.095 af (75% of inflow) Center-of-Mass det. time= 42.6 min ( 851.9 -809.4 ) Volume Invert Avail.Storage Storage Description #1 856.10' 243,941 cf Custom Stage Data (Prismatic) Listed below (Recalc) Proposed Conditions Type II 24-hr 100-yr Storm Event Rainfall=6.00" Prepared by {enter your company name here} Printed 6/25/2008 HydroCAD® 8.50 s/n 003363 © 2007 HydroCAD Software Solutions LLC Page 19 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 856.10 11 0 0 858.00 969 931 931 860.00 3,477 4,446 5,377 862.00 6,568 10,045 15,422 864.00 10,029 16,597 32,019 865.00 11,872 10,951 42,969 866.00 18,529 15,201 58,170 868.00 22,903 41,432 99,602 870.00 27,564 50,467 150,069 872.00 32,509 60,073 210,142 873.00 35,089 33,799 243,941 Device Routing Invert Outlet Devices #1 Primary 866.00' 33.0" x 100.0' long Culvert RCP, square edge headwall, Ke= 0.500 Outlet Invert= 865.00' S= 0.0100 '/' Cc= 0.900 n= 0.013 #2 Device 1 866.10' Custom Weir/Orifice, C= 2.62 Head (feet) 0.00 3.25 3.25 6.00 Width (feet) 0.00 6.00 6.00 6.00 Primary OutFlow Max=42.28 cfs @12.16 hrs HW=869.56' (Free Discharge) 1=Culvert (Inlet Controls 42.28 cfs @7.12 fps) 2=Custom Weir/Orifice (Passes 42.28 cfs of 53.85 53.85 cfs potential flow) Summary for Link 1L: Site Infrastructure Inflow Area = 7.620 ac, 0.00% Impervious, Inflow Depth > 2.97" for 100-yr Storm Event event Inflow = 19.53 cfs @12.25 hrs, Volume= 1.885 af Primary = 19.41 cfs @12.42 hrs, Volume= 1.880 af, Atten= 1%, Lag= 10.0 min Primary outflow = Inflow delayed by 10.0 min, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs SUMMARY ??WESTWOOD PROFESSIONAL SERVICES, INC. (952) 937-5150 APPENDIX C WATER QUALITY PONDNET 2.1 FLOW AND PHOSPHORUS ROUTING IN POND W. Walker March 1989 Press ALT-G for G TITLE--> PONDNET TEST CASE INPUT VARIABLES.... UNITS case labels NURP Pond 1 Pond 2 watershed area acres 100 11.4 0 runoff coefficient -0.2 0.75 0 pond surface area acres 1 0.43 0 pond mean depth feet 7.2 0 upstream pond p load lbs/yr 0 0 0 upstream pond outflow ac-ft/yr 0 0 0 OUTPUT VARIABLES........ outflow p load lbs/yr 43.64625 14.9709 #DIV/0! outflow volume ac-ft/yr 66.66667 28.5 0 outflow p conc ppb 240.8734 193.2652 #DIV/0! pond removal % 62.94452 70.26847 #DIV/0! total removal % 62.94256 70.26689 #DIV/0! ASSUMED EXPORT FACTORS............. period length yrs 0.5 0.5 0.5 period precipitation inches 20 20 20 runoff total p ppb 650 650 650 runoff ortho p/total p -0.3 0.3 0.3 relative decay rate -1 1 1 unit runoff in/yr 8 30 0 unit export lbs/ac-y 1.177862 4.416984 0 PONDSIZ -Version 2.1 -W. Walker INPUT VARIABLE UNITS VALUES NOTES case title ---------------> Pond A watershed area acres 11.4 pervious curve number -60 from SCS tables, for AMC=2 impervious fraction -0.58 design storm inches 2.5 VLAWMO criterion = 2.5 inches antecedent moisture cond. 2 (1,2,or 3), VLAWMO criterion = 2 pond maximum depth feet 10 <= 10 ft bench width bc feet 10 >= 10 ft bench slope bc ft/ft 10 >= 10 ft horiz /ft vertical side slope ab ft/ft 3 >= 3 ft horiz /ft vertical pond shape factor 2 1=triangle,2=rectangle,3=ellipse length/width ratio -4 >= 3 top length c feet 300.00 adjust to achieve target volume OUTPUT VARIABLE UNITS VALUE target volume acre-ft 1.38 = design storm runoff volume DRA-1 Onsite Southern Drainage Pond Pond to ditch Drainage Diagram for NURP Prepared by {enter your company name here}, Printed 6/25/2008 HydroCAD® 8.50 s/n 003363 © 2007 HydroCAD Software Solutions LLC Subcat Reach Pond Link NURP Type II 24-hr 2.5" Storm Event Rainfall=2.50" Prepared by {enter your company name here} Printed 6/25/2008 HydroCAD® 8.50 s/n 003363 © 2007 HydroCAD Software Solutions LLC Page 2 Time span=0.00-24.00 hrs, dt=0.05 hrs, 481 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method -Pond routing by Stor-Ind method Subcatchment DRA-1: Onsite Southern Runoff Area=11.400 ac 62.98% Impervious Runoff Depth>1.45" Tc=10.0 min CN=89 Runoff=24.99 cfs 1.379 af Pond Pond: Pond to ditch Peak Elev=866.10' Storage=60,044 cf Inflow=24.99 cfs 1.379 af Outflow=0.00 cfs 0.000 af Total Runoff Area = 11.400 ac Runoff Volume = 1.379 af Average Runoff Depth = 1.45" 37.02% Pervious = 4.220 ac 62.98% Impervious = 7.180 ac NURP Type II 24-hr 2.5" Storm Event Rainfall=2.50" Prepared by {enter your company name here} Printed 6/25/2008 HydroCAD® 8.50 s/n 003363 © 2007 HydroCAD Software Solutions LLC Page 3 Summary for Subcatchment DRA-1: Onsite Southern Drainage Runoff = 24.99 cfs @12.01 hrs, Volume= 1.379 af, Depth> 1.45" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type II 24-hr 2.5" Storm Event Rainfall=2.50" Area (ac) CN Description * 0.500 100 Pond NWL 6.680 98 Paved parking & roofs 4.220 74 >75% Grass cover, Good, HSG C 11.400 89 Weighted Average 4.220 Pervious Area 7.180 Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Summary for Pond Pond: Pond to ditch Inflow Area = 11.400 ac, 62.98% Impervious, Inflow Depth > 1.45" for 2.5" Storm Event event Inflow = 24.99 cfs @12.01 hrs, Volume= 1.379 af Outflow = 0.00 cfs @24.00 hrs, Volume= 0.000 af, Atten= 100%, Lag= 719.1 min Primary = 0.00 cfs @24.00 hrs, Volume= 0.000 af Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Peak Elev= 866.10' @24.00 hrs Surf.Area= 18,749 sf Storage= 60,044 cf Plug-Flow detention time= 1,015.1 min calculated for 0.000 af (0% of inflow) Center-of-Mass det. time= 619.4 min ( 1,440.0 -820.6 ) Volume Invert Avail.Storage Storage Description #1 856.10' 243,941 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 856.10 11 0 0 858.00 969 931 931 860.00 3,477 4,446 5,377 862.00 6,568 10,045 15,422 864.00 10,029 16,597 32,019 865.00 11,872 10,951 42,969 866.00 18,529 15,201 58,170 868.00 22,903 41,432 99,602 870.00 27,564 50,467 150,069 872.00 32,509 60,073 210,142 873.00 35,089 33,799 243,941 NURP Type II 24-hr 2.5" Storm Event Rainfall=2.50" Prepared by {enter your company name here} Printed 6/25/2008 HydroCAD® 8.50 s/n 003363 © 2007 HydroCAD Software Solutions LLC Page 4 Device Routing Invert Outlet Devices #1 Primary 866.00' 33.0" x 100.0' long Culvert RCP, square edge headwall, Ke= 0.500 Outlet Invert= 865.00' S= 0.0100 '/' Cc= 0.900 n= 0.013 #2 Device 1 866.10' Custom Weir/Orifice, C= 2.62 Head (feet) 0.00 3.25 3.25 6.00 Width (feet) 0.00 6.00 6.00 6.00 Primary OutFlow Max=0.00 cfs @24.00 hrs HW=866.10' (Free Discharge) 1=Culvert (Passes 0.00 cfs of 0.07 cfs potential flow) 2=Custom Weir/Orifice (Weir Controls 0.00 cfs @0.06 fps) SUMMARY ??WESTWOOD PROFESSIONAL SERVICES, INC. (952) 937-5150 APPENDIX D DETAILS