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HomeMy WebLinkAboutStudies APPLICANT 4/24/2020Stormwater Management Plan New Offices at: Lots 500 McVay Highway Glenwood, OR For Weyerhaeuser NR Co. EXPIRES: 12/31/20 Prepared by: Christopher Morris, E.I.T. chrismC@branchenoineerino.com Prepared using: Springfield's Engineering Design Standards and Procedures Manual Eugene's 2014 Stormwater Management Manual E'N0GINEERING= Since 1977 civil • transportation structural • geotechnical SURVEYING www.BranchEngineering.com April 24, 2020 Contents Page No. 1.0 Introduction.............................................................................................................................. l 2.0 Existing Conditions ............... 2.1 Topography 2.2 Soils 2.3 Existing Stormwater System 2.4 Infiltration Rates 3.0 Proposed Development ........................ 3.1 Pollutants of Concern 3.2 Name and Status ofBeceiving Waters 4.0 Stormwater Constraints..........................................................................................................2 5.0 Proposed Development Stormwater Description 6.0 Hydrologic and Hydraulic Analysis.......................................................................................2 6.1 Computer Model 6.2 Computer Model Data 7.0 Maintenance.............................................................................................................................3 8.0 Conclusion Appendices Appendix A Appendix B Appendix C Appendix D Description Soils Map and Description HydroCAD Report Operations and Maintenance Plan Infiltration Data 1.0 Introduction The subject properties are one parcel of land approximately 2.20 acres in size and a portion of a second parcel of land approximately 0. 48 acres in size combined to make up approximately 2.68 acres in size and located in Glenwood, Oregon. The subject properties are listed as Tax Map 18-03-03-14, Tax Lots 500 and 700. A single commercial office building, parking lot areas, concrete walkways, landscape and stormwater treatment areas and associated utilities are the proposed development at the site. This study and report was prepared to address the City of Springfield's stormwater requirements for the development. 2.0 Existing Conditions The parcels are 100% of a single lot and a portion of a second lot that fronts McVay Highway to the east, Nugget Way to the north, Newman Street to the northeast and railroad Right -of -Way to the west. 2.1 Topography The existing site is relatively flat, but generally drains from southeast to northwest. 2.2 Soils According to the Web Soil Survey of Lane County. Ore%! , by the Natural Resource Conservation Service, the soils on the site are Newberg -Urban land complex (Soil Number 97). Newberg -Urban land complex is described as a recent silty alluvium and a well -drained soil of Hydrologic Group A A soil map and descriptions are attached as Appendix A 2.3 Existing Stormwater System The project site is relatively unimproved without an established drainage system There is no improved drainage system in the vicinity for the development to drain to. All stormwater for the development will need to be onsite destination and disposal. 2.4 Infiltration Rates Infiltration facilities are being proposed for the site's stormwater disposal. An Encased Falling Head Infiltration Test has been performed at the site. Infiltration rates varied across the site. A SafetyFactor of 2 was applied to all assumed rates at stormwater facility locations and was used for modeling purposes. Infiltration Data is provided in Appendix E 3.0 Proposed Development The proposed development is to construct a single commercial office building, associated parking and concrete walkways. The total impervious area for the entire site is approximately 1.94 acres (84, 500 sq ft). 3.1 Pollutants of Concern The reasonably expected pollutants of concern from this type of development are: • Nutrients • Pesticides, Herbicides, Fungicides • Metals (Zinc, Copper, Lead etc.) • Oil, grease and other petroleum • Sediment • litter • Oxygen demanding materials • Increased thermal loading 3.2 Name and Status of Receiving Waters There are no downstream receiving waters as all stormwater will be disposed of onsite. According to the City of Springfield's Wellhead Protection Areas Map, the project site is located outside the 100 -year Zone of Concentration (100 -year Time of Travel) wellhead protection area designated by the City and the Springfield Utility Board. 4.0 Stormwater Constraints The site is relatively flat and there are no public stormwater systems available to connect to. Therefore, runoff from all storms up through the 25 -year storm event needs to be fully infiltrated and disposed of onsite. 5.0 Proposed Development Stormwater Description The City of Springfield defers to Eugene's Stormwater Management Manual (2014) for stormwater treatmentfacility design when designinformationis notincludedin the City of Springfield Engineering and Design Standards and Procedures Manual. The proposed development is broken up into six drainage basins that either shed directly to stormwater treatment and infiltration facilities or to catch basins that drain to one of those three facilites. 6.0 Hydrologic and Hydraulic Analysis 6.1 Computer Model In preparing this Stormwater Management Plan for the project site, Branch Engineering utilized the HydroCAD 10.0 software. This is a computer program used to model, analyze and design hydrosystems of drainage basins. HydroCAD computes Santa Barbara Urban Hydrographs (SBUH) using rainfall data supplied by the designer. The SBUH method is a recognized analysis method by the City of Springfield and is appropriate for a project site of this size. Once the appropriate data is input to HydroCAD, each drainage basin has a hydrograph and runoff flow for the desired storm event 6.2 Computer Model Data HydroCAD needs data supplied from the designer that describes the drainage basin in order to create the hydrograph. Below is the data that is needed to describe each drainage basin. o Storm Event For the purposes of this design, the City of Springfield's design storm events are as follows: Water Quality Event 2 -year Storm Event 10 -year Storm Event 25 -year Storm Event 0.83 inches / 24 hours 3.30 inches / 24 hours 4.30 inches / 24 hours 4.80 inches / 24 hours o Impervious Area Pavement, sidewalks, hardscapes and rooftops are all impervious surfaces. o Pervious Area Lawns and open space are pervious areas. Each drainage basin's pervious area is all that area that is not impervious. o Runoff Curve Numbers Each drainage basin has a Runoff Curve Number for the impervious areas and the pervious areas. The Runoff Curve Number is based on the type of surface and the Hydrologic Group of the soils. As stated earlier in the report, the soils on the site are in Soil Hydrologic Group C. Per Table 2-2a of the Urban Hydrology for Small Watersheds (TR -S S) table, the Curve Number is 68 for pervious areas and 98 for impervious areas. o Time of Concentration The minimum time of concentration of five minutes was used for modeling. 7.0 Maintenance The treatment and infiltration facilities are located on private property and will be owned and maintained by the property owners. Maintenance will be per the City of Springfield's Engineering Design Standards and Procedures Manual. Repairs to the facilities shall be made in accordance with the City of Springfield's Engineering Design Standards and Procedures Manual. The operations and maintenance documents are attached as Appendix D. 8.0 Conclusion The proposed stormwater system for the new office building and parking areas additions have been designed in accordance with the City of Springfield's Engineering Design Standards and Procedures Manual. Soils Map and Description 40, \ /'\ 6XI'00� ^^ �� � �<\. � , 01 Nl, 4:0 V* MH N@p mIW nooDt w r m "emk—, Soil Map—Lane County Area, Oregon _SD, Natural Resources web Sol Survey 1211&2919 alaill Conservation Service National Cooperative Sail Survey Page 2 of 3 MAP LEGEND MAP INFORMATION Area at Wake. tA09 Spoil Area The sal surveys that comprise your AOI were mapped at Areaalnteresr(AQII Q army Spa 1:20,090. Soils Very Sony SpaWaming: Soil Map may not be valud al Mrs scale. 0 Soil Map Unit Polygons 9 VJrf S p a Enlargement of maps bethe scale of mapping can cause ,.,. Soil Map Unic Lines md Sell of the etail of mapping and accuracy of soil 4 Other line placement. The maps do not show the small areas of Map Unit Points contrasting soils that could have been shown at a more detailed Special Line FeaturesSoil Special Point Features scale. Lg Blowout water Features Streams and Canals Please rely on the bar scale on each map sheet for map ® Borrow Pit measurements. Trenspartatian Clay Spot Rails Source of Map: Natural Resources Conservation Service 0 Closed Depresdan Web Soil SurveyURL: Interstate Highways Coordinate System: web Mercator(EPSG:3m5]) Gravel Pit US Routes Maps from the Web Soil Survey are based on the Web Mercator Gravely Spa Major Roads projection, which preserves and shape but ion that schdistorts and area, projection that preserves area, such as the ® Landfill Local Roads Abersdistance o Albers equal-area conic projection, should be used if more Lava Flow accurate calculations of distance or area are req uired, Background aga Marsh or swamp . Aerial Photography This productis generated from the USDA­gRCS tended data as of Ne version date(s) listed below .�. Mine or Query Soil Survey Area: Lane County Area, ® Miscellaneous Ydscer ep10,Oregon 2019 Survey Area Data: Version 16, Sep 10, 2019 ® Perennial VMmer Sail map units are labeled (as space allows) for map scales y, Rock Outcrop 1:50,099 or larger. A Saline Spot Dates) aerial images were photographed: Jun 12, 2019i 19, 2019 Sandy Spot The orihophoto or other base map on which the soil lines were Severely Eroded Spot compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor Sinkhole shifting ofmap unit boundaries may be evident, �p Slide or Slip Sodic Spot _SD, Natural Resources web Sol Survey 1211&2919 alaill Conservation Service National Cooperative Sail Survey Page 2 of 3 Sal Map�ane Connly Area, Oregon Map Unit Legend LSIA Natural Resources Web Soil Survey 12/182019 iMi Conservation Serme National Cooperative Soil Survey Page 3 ot3 Map Unit Symbd Map U-1 Name Acres in AOI Pescara of AOI 23 Canrasi ffian land cornplex 0.1 2.0% w Ne. ergs ffian land cornplex 5.0 98.0% Totals far Area of Interest 5.1 100.0% LSIA Natural Resources Web Soil Survey 12/182019 iMi Conservation Serme National Cooperative Soil Survey Page 3 ot3 Map Unit Desaiptim: Neeberg-Urban land cernplex--Lane Cmnty Area, Oregon Lane County Area, Oregon 97—Newberg-Urban land complex Map Unit Setting National map unit symbol. 239x Elevation. 300 to 850 feet Mean annual precipitation: 40 to 60 inches Mean annual air temperature: 52 to 54 degrees F Frost -free period. 165 to 210 days Farmland classification. Farm land of statewide importance Map Unit Composition Newberg and similar soils: 50 percent Urban land. 35 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Newberg Setting Landform: Flood plains Landform position (three-dimensional): Tread Down-slope shape: Linear Across -slope shape: Linear Parent material. Recent silty alluvium Typical profile H1 - 0 to 14 inches. fine sandy loam H2 - 14 to 65 inches: fine sandy loam Properties and qualities Slope: 0 to 3 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Capacity of the most limitirg layer to transmit water(Ksat): High (1.98 to 5.95 in/hr) Depth to water table: More than 80 inches Frequency of flooding. Occasional Frequencyofponding. None Available water storage in profile: Moderate (about 8.4 inches) Interpretive groups Lard capability classification (irrigated): 2w Lard capability classification (nonirrigated): 2w Hydrologic Sal Group: A Hydric soil rating: No Description of Urban Land Interpretive groups Lard capability classification (irrigated): None specified Lard capability classification (nonirrigated): 8 LSM Natural Resources Wieb Soil Survey 12/19x2019 Conservation SerNce National Cooperative Soil Survey Pagel oft Map Unit Deso iptim: Ne.Merg-Urloan land canplex--lane County Nes, Cregou Hydric soil rating: No Data Source Information Soil Survey Area: Lane County Area, Oregon Survey Area Data: Version 16, Sep 10, 2019 LSM Natural Resources Web Soil Survey 12/192019 irk Conservation Service National Cooperative Soil Survey Page 2 oft /_1»:1k,IQKa-� HydroCAD Report Al'; o --1s i e A4$ (new Pond) (new Pond) (new�ond) P nd Basin 1 30S Basin 2 26S 29S V 27$ Bas Roof 28$ Basin 3 o- 42 Basin 5 Basin 4 Pond O Aggregate 44$ Btin 6 41 ca Pond 2P (new Pond) SUbcat Reach on Link Routing Diagmm for Design Model Prepared by Microsoft, Printed 4/24/2020 HydroCAD®10.00-24 s/n 10784 ®2018 HydroCAD Software SolNlons LLC Design Model Type IA 24 -hr 2 yr Rainfall=3.30" Prepared by Microsoft Printed 4/24/2020 HydroCAD®10.00-24 s/n 10784 m 2018 HydroCAD Software Solutions LLC Pace 2 Time span=0.00-36.00 hrs, dt=0.01 hrs, 3601 points x 2 Runoff by SCS TR -20 method, UH=SCS, Weighted -CN Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method Subcatchment 4S: Basin 1 Runoff Area=21.844 at 100.00%Impervious Runoff Depth=3.07" Tc=5.0 min CN=98 Runoff=0.39 cfs 0.128 of Subcatchment 265: Basin Root Runoff Area=18.085 at 100.00%Impervious Runoff Depth=3.07" Tc=5.0 min CN=98 Runoff=0.33 cfs 0.106 of Subcatchment 275: Basin 5 Runoff Area=4,990 at 100.00%Impervious Runoff Depth=3.07" Tc=5.0 min CN=98 Runoff=0.09 cfs 0.029 of Subcatchment 285: Basin 4 Runoff Area=14.750 at 100.00% Impervious Runoff Depth=3.07" Tc=5.0 min CN=98 Runoff=0.27 cfs 0.087 of Subcatchment 295: Basin 3 Runoff Area=13.035 at 100.00% Impervious Runoff Depth=3.07" Tc=5.0 min CN=98 Runoff=0.23 cfs 0.076 of Subcatchment 305: Basin 2 Runoff Area=10.612 at 100.00% Impervious Runoff Depth=3.07" Tc=5.0 min CN=98 Runoff=0.19 cfs 0.062 of Subcatchment 445: Basin 6 Runoff Area=3,020 at 100.00% Impervious Runoff Depth=3.07" Tc=5.0 min CN=98 Runoff=0.05 cfs 0.018 of Pond 2P: (new Pond) Peak Elev=447.57' Inflow=0.05 cfs 0.018 of 8.0" Round Culven n=0.011 L=54.0' S=0.0454'f Outflow=0.05 cfs 0.018 of Pond 17P: (new Pond) Peak Elev=446.35' Inflow=0.19 cfs 0.062 of 8.0" Round Culven n=0.011 L=180.0' S=0.0117'/' Outflow=0.19ds 0.062 of Pond 18P: (new Pond) Peak Elev=446.63' Inflow=0.19 cfs 0.062 of 8.0" Round Culven n=0.011 L=30.0' S=0.0050'f Outflow=0.19 cfs 0.062 of Pond 19P: (new Pond) Peak Elev=446.59' Inflow=0.19 cfs 0.062 of 8.0" Round Culven n=0.011 L=42.0' S=0.0060 V Outflow=0.19 cfs 0.062 of Pond 38P: Aggregate Peak Elev=442.72' Storage=714 cf Inflow=0.58 as 0.220 of Outflow=0.24 as 0.220 at Pond 41 P: Pond Peak Elev=445.18' Storage=2,601 cf Inflow=0.88 cfs 0.287 at Primary=0.00 cfs 0.000 of Secondary=0.20 cfs 0.287 of Outflow=0.20 cfs 0.287 at Pond 42P: Pond Peak Elev=445.22' Storage=119 cf Inflow=0.09 cfs 0.029 at Primary=0.00 cfs 0.000 of Secondary=0.03 cfs 0.029 of Outflow=0.03 cfs 0.029 at Pond 43P: Pond Peak Elev=445.19' Storage=1,644 cf Inflow=0.58 cfs 0.190 at Primary=0.50 cfs 0.080 of Secondary=0.05 cfs 0.110 of Outflow=0.55 cfs 0.190 of Design Model Type IA 24 -hr 2 yr Rainfall=3.30" Prepared by Microsoft Printed 4/24/2020 HydroCAD@ 10.00-24 s/n 10784 © 2018 HydroCAD Software Solutions LLC Paae 3 Summary for Subcatchment 4S: Basin 1 Runoff = 0.39 cis @ 7.86 hrs, Volume= 0.128 af, Depth= 3.07" Runoff by SCS TR -20 method, UH=SCS, Weighted -CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type IA 24 -hr 2 yr Rainfall=3.30" 21,844 98 Paved parking, HSG B 21,844 100.00% Impervious Area Tc Length Slope Velocity Capacity Description 5.0 Summary for Subcatchment 26S: Basin Roof Runoff = 0.33 cis @ 7.86 hrs, Volume= 0.106 af, Depth= 3.07" Runoff by SCS TR -20 method, UH=SCS, Weighted -CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type IA 24 -hr 2 yr Rainfall=3.30" Area (sf) CN Description 18,085 98 Paved parking, HSG B 18,085 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Summary for Subcatchment 27S: Basin 5 Runoff = 0.09 cfs @ 7.86 hrs, Volume= 0.029 af, Depth= 3.07" Runoff by SCS TR -20 method, UH=SCS, Weighted -CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type IA 24 -hr 2 yr Rainfall=3.30" 4,990 98 Paved parking, HSG B 4,990 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Design Model Type IA 24 -hr 2 yr Rainfall=3.30" Prepared by Microsoft Printed 4/24/2020 HydroCAD@ 10.00-24 s/n 10784 © 2018 HydroCAD Software Solutions LLC Paae 4 Summary for Subcatchment 28S: Basin 4 Runoff = 0.27 cis @ 7.86 hrs, Volume= 0.087 af, Depth= 3.07" Runoff by SCS TR -20 method, UH=SCS, Weighted -CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type IA 24 -hr 2 yr Rainfall=3.30" 14,750 98 Paved parking, HSG B 14,750 100.00% Impervious Area Tc Length Slope Velocity Capacity Description 5.0 Summary for Subcatchment 29S: Basin 3 Runoff = 0.23 cis @ 7.86 hrs, Volume= 0.076 af, Depth= 3.07" Runoff by SCS TR -20 method, UH=SCS, Weighted -CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type IA 24 -hr 2 yr Rainfall=3.30" Area (sf) CN Description 13,035 98 Paved parking, HSG B 13,035 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Summary for Subcatchment 30S: Basin 2 Runoff = 0.19 cfs @ 7.86 hrs, Volume= 0.062 af, Depth= 3.07" Runoff by SCS TR -20 method, UH=SCS, Weighted -CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type IA 24 -hr 2 yr Rainfall=3.30" 10,612 98 Paved parking, HSG B 10,612 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Design Model Type IA 24 -hr 2 yr Rainfall=3.30" Prepared by Microsoft Printed 4/24/2020 HydroCAD@ 10.00-24 s/n 10784 02018 HydroCAD Software Solutions LLC Paae 5 Summary for Subcatchment 44S: Basin 6 Runoff = 0.05 cfs @ 7.86 hrs, Volume= 0.018 af, Depth= 3.07" Runoff by SCS TR -20 method, UH=SCS, Weighted -CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type IA 24 -hr 2 yr Rainfall=3.30" 3,020 98 Paved parking, HSG B 3,020 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Summary for Pond 213: (new Pond) Inflow Area = 0.069 ac,100.00% Impervious, Inflow Depth = 3.07" for 2 yr event Inflow = 0.05 cfs @ 7.86 hrs, Volume= 0.018 of Outflow = 0.05 cfs @ 7.86 hrs, Volume= 0.018 af, Atten= 0%, Lag= 0.0 min Primary = 0.05 cfs @ 7.86 hrs, Volume= 0.018 of Routing by Dyn-Slor-Ind method, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 447.57'@ 7.86 hrs Flood Elev= 477.30' Device Routing Invert Outlet Devices #1 Primary 447.45' 8.0" Round Culvert L= 54.0' Ke= 0.500 Inlet/ Outlet Invert= 447.45'/445.00' S=0.0454/' Cc= 0.900 n= 0.011, Flow Area= 0.35 sf Primary OutFlow Max=0.05 cfs @ 7.86 hrs HW=447.57' TW=444.83' (Dynamic Tailwater) 1=Culvert (Inlet Controls 0.05 cfs @ 1.20 fps) Summary for Pond 17P: (new Pond) Inflow Area = 0.244 ac,100.00% Impervious, Inflow Depth = 3.07" for 2 yr event Inflow = 0.19 cfs @ 7.86 hrs, Volume= 0.062 of Outflow = 0.19 cfs @ 7.86 hrs, Volume= 0.062 af, Atten= 0%, Lag= 0.0 min Primary = 0.19 cfs @ 7.86 hrs, Volume= 0.062 of Routing by Dyn-Stor-Ind method, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 446.35'@ 7.87 hrs Flood Elev= 477.30' Device Routing Invert Outlet Devices #1 Primary 446.10' 8.0" Round Culvert L= 180.0' Ke= 0.500 Inlet /Outlet Invert= 446.10'/444.00' S=0.0117'/' Cc= 0.900 n= 0.011, Flow Area= 0.35 sf Design Modei Type IA 24 -hr 2 yr Rainfall=3.30" Prepared by Microsoft Printed 4/24/2020 HydroCAD@ 10.00-24 s/n 10784 02018 HydroCAD Software Solutions LLC Paae 6 tPrimaryOutFlow Max=0.19 cfs @ 7.86 hrs HW=446.35' TW=445.18' (Dynamic Tailwater) 1=Culvert (Outlet Controls 0.19 cfs @ 2.34 fps) Summary for Pond 18P: (new Pond) Inflow Area = 0.244 ac,100.00 % Impervious, Inflow Depth = 3.07" for 2 yr event Inflow = 0.19 cfs @ 7.86 hrs, Volume= 0.062 of Outflow = 0.19 cfs @ 7.86 hrs, Volume= 0.062 af, Atten= 0%, Lag= 0.0 min Primary = 0.19 cfs @ 7.86 hrs, Volume= 0.062 of Routing by Dyn-Stor-Ind method, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 446.63'@ 7.86 hrs Device Routing Invert Outlet Devices #1 Primary 446.15' 8.0" Round Culvert L= 30.0' Ke= 0.500 Inlet /Outlet Invert= 446.15'/446.00' S=0.0050'/' Cc= 0.900 n= 0.011, Flow Area= 0.35 sf PrimaryOutFlow Max=0.19 cfs @ 7.86 hrs HW=446.63' TW=446.59' (Dynamic Tailwater) 1­1=Culvert (Outlet Controls 0.19 cfs @ 1.00 fps) Summary for Pond 19P: (new Pond) Inflow Area = 0.244 ac,100.00% Impervious, Inflow Depth = 3.07" for 2 yr event Inflow = 0.19 cfs @ 7.86 hrs, Volume= 0.062 of Outflow = 0.19 cfs @ 7.86 hrs, Volume= 0.062 af, Atten= 0%, Lag= 0.0 min Primary = 0.19 cfs @ 7.86 hrs, Volume= 0.062 of Routing by Dyn-Stor-Ind method, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 446.59'@ 7.86 hrs Device Routing Invert Outlet Devices #1 Primary 446.30' 8.0" Round Culvert L= 42.0' Ke= 0.500 Inlet /Outlet Invert= 446.30'/446.05' S= 0.0060'P Cc= 0.900 n= 0.011, Flow Area= 0.35 sf ZPrimaryOutFlow Max=0.19 cfs @ 7.86 hrs HW=446.59' TW=446.35' (Dynamic Tailwater) 1=Culvert (Outlet Controls 0.19 cfs @ 1.95 fps) Summary for Pond 3813: Aggregate Inflow Area = 0.860 ac,100.00% Impervious, Inflow Depth > 3.06" for 2 yr event Inflow = 0.58 cfs @ 8.02 hrs, Volume= 0.220 of Outflow = 0.24 cfs @ 7.66 hrs, Volume= 0.220 af, Atten= 58%, Lag= 0.0 min Discarded = 0.24 cfs @ 7.66 hrs, Volume= 0.220 of Routing by Dyn-Sfor-Ind method, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 442.72'@8.83 hrs Surf.Area= 3,000 sf Storage= 714 cf Plug -Flow detention time= 11.2 min calculated for 0.220 of (100% of inflow) Design Modei Type IA 24 -hr 2 yr Rainfall=3.30" Prepared by Microsoft Printed 4/24/2020 HydroCAD@ 10.00-24 s/n 10784 02018 HydroCAD Software Solutions LLC Paae 7 Center -of -Mass det. time= 11.1 min ( 889.9 - 878.8) Volume Invert Avail.Storaae Storage Description #1 442.00' 1,980 cf Custom Stage Data (Prismatic) Listed below (Recalc) 6,000 cf Overall x 33.0% Voids Elevation Surf.Area Inc.Store Cum.Store (feet) (sq -ft) (cubic -feet) (cubic -feet) 442.00 3,000 0 0 444.00 3,000 6,000 6,000 Device Routing Invert Outlet Devices #1 Discarded 442.00' 3.500 in/hr Exfiltration over Surface area Phase -In= 0.01' Discarded OutFlow Max=0.24 cfs @ 7.66 hrs HW=442.02' (Free Discharge) L7=Exfiltration (Exfiltration Controls 0.24 cfs) Summary for Pond 41 P: Pond Inflow Area = 1.122 ac,100.00% Impervious, Inflow Depth = 3.07" for 2 yr event Inflow = 0.88 cfs @ 7.86 hrs, Volume= 0.287 of Outflow = 0.20 cfs @ 9.80 hrs, Volume= 0.287 at, Atten= 77%, Lag= 116.5 min Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 of Secondary = 0.20 cfs @ 9.80 hrs, Volume= 0.287 of Routing by Dyn-Stor-Ind method, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 445.18'@ 9.80 hrs Surf.Area= 3,471 sf Storage= 2,601 cf Plug -Flow detention time= 119.2 min calculated for 0.287 of (1000/0 of inflow) Center -of -Mass det. time= 119.1 min ( 782.9 - 663.7) Volume Invert Avail.Storage Storage Description #1 444.25' 8,449 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq -ft) (cubic -feet) (cubic -feet) 444.25 2,140 0 0 446.50 5,370 8,449 8,449 Device Routing Invert Outlet Devices #1 Primary 448.50' 2.0' long x 0.50' rise Sharp -Crested Rectangular Weir 2 End Contraction(s) 1.0' Crest Height #2 Secondary 444.25' 2.500 in/hr Exfiltration over Surface area Phase -In= 0.01' Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=444.25' (Free Discharge) 1-11 =Sharp -Crested Rectangular Weir ( Controls 0.00 cfs) Secondary OutFlow Max=0.20 cfs @ 9.80 hrs HW=445.18' (Free Discharge) 2=Exfiltration (Exfiltration Controls 0.20 cfs) Design Model Type IA 24 -hr 2 yr Rainfall=3.30" Prepared by Microsoft Printed 4/24/2020 HydroCAD®10.00-24 s/n 10784 m 2018 HydroCAD Software Solutions LLC Paae 8 Summary for Pond 42P: Pond Inflow Area = 0.115 ac,100.00% Impervious, Inflow Depth = 3.07" for 2 yr event Inflow = 0.09 cfs @ 7.86 hrs, Volume= 0.029 of Outflow = 0.03 cfs @ 8.43 hrs, Volume= 0.029 af, Atten= 61%, Lag= 34.6 min Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 of Secondary = 0.03 cfs @ 8.43 hrs, Volume= 0.029 of Routing by Dyn-Stor-Ind method, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 445.22'@8.43 hrs Surf.Area= 602 sf Storage= 119 cf Plug -Flow detention time= 15.1 min calculated for 0.029 of (100% of inflow) Center -of -Mass det. time= 15.1 min ( 678.8 - 663.7) Volume Invert Avail.Storage Storage Description #1 445.00' 1,940 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq -ft) (cubic -feet) (cubic -feet) 445.00 500 0 0 447.00 1,440 1,940 1,940 Device Routing Invert Outlet Devices #1 Primary 446.50' 2.0' long x 0.50' rise Sharp -Crested Rectangular Weir 2 End Contraction(s) 1.0' Crest Height #2 Secondary 445.00' 2.500 in/hr Pxdiltration over Surface area Phase -In= 0.01' Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=445.00' TW=442.00' (Dynamic Tailwater) t1 =Sharp -Crested Rectangular Weir ( Controls 0.00 cfs) Secondary OutFlow Max=0.03 cfs @ 8.43 hrs HW=445.22' TW=442.69' (Dynamic Tailwater) 2=Exfiltration (Exfiltration Controls 0.03 cfs) Summary for Pond 43P: Pond Inflow Area = 0.745 ac,100.00% Impervious, Inflow Depth = 3.07" for 2 yr event Inflow = 0.58 cfs @ 7.86 hrs, Volume= 0.190 of Outflow = 0.55 cfs @ 8.02 hrs, Volume= 0.190 af, Atten= 6%, Lag= 9.6 min Primary = 0.50 cfs @ 8.02 hrs, Volume= 0.080 of Secondary = 0.05 cfs @ 8.02 hrs, Volume= 0.110 of Routing by Dyn-Stor-Ind method, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 445.19'@ 8.02 hrs Surf.Area= 1,395 sf Storage= 1,644 cf Plug -Flow detention time= 246.6 min calculated for 0.190 of (1000/0 of inflow) Center -of -Mass det. time= 245.9 min ( 909.6 - 663.7) Volume Invert Avail.Storage Storage Description #1 443.50' 2,100 cf Custom Stage Data (Prismatic) Listed below (Recalc) Design Nbclei Type IA 24-hr 2 yr Rainfall=3.30" Prepared by Microsoft Printed 4/24/2020 HWroCAD®10.00-24 s/n 10784 m 2018 HydroCAD Software Solutions LLC Pace 9 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 443.50 550 0 0 445.50 1,550 2,100 2,100 Device Routing Invert Outlet Devices #1 Primary 445.00' 2.0' long x 0.50' rise Sharp-Crested Rectangular Weir 2 End Contraction(s) 1.0' Crest Height #2 Secondary 443.50' 1.500 in/hr Exfiltration over Surface area Phase-In= 0.01' #3 Device 1 444.00' 8.0" Round Culvert L= 115.0' Ke= 0.500 Inlet/ Outlet Invert= 444.00'/443.00' S=0.0087'/' Cc= 0.900 n= 0.011, Flow Area= 0.35 sf Primary OutFlow Max-0.50 cfs @ 8.02 hrs HW=445.19' TW=442.39' (Dynamic Tailwater) 't'114harp-Crested Rectangular Weir (Passes 0.50 cfs of 0.54 cfs potential flow) L3=Culvert (Outlet Controls 0.50 cfs @ 1.44 fps) Secondary OutFlow Max=0.05 cfs @ 8.02 hrs HW=445.19' TW=442.39' (Dynamic Tailwater) 2=Exfiltration (Exfiltration Controls 0.05 cfs) Design Model Type IA 24 -hr 5 yr Rainfall=3.80" Prepared by Microsoft Printed 4/24/2020 HydroCADO 10.00-24 s/n 10784 02018 HydroCAD Software Solutions LLC Pace 10 Time span=0.00-36.00 hrs, dt=0.01 hrs, 3601 points x 2 Runoff by SCS TR -20 method, UH=SCS, Weighted -CN Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method Subcatchment 4S: Basin 1 Runoff Area=21.844 at 100.00%Impervious Runoff Depth=3.57" Tc=5.0 min CN=98 Runoff=0.45 cfs 0.149 of Subcatchment 265: Basin Roof Runoff Area=18.085 at 100.00%Impervious Runoff Depth=3.57" Tc=5.0 min CN=98 Runoff=0.38 cfs 0.123 of Subcatchment 275: Basin 5 Runoff Area=4,990 at 100.00%Impervious Runoff Depth=3.57" Tc=5.0 min CN=98 Runoff=0.10 cfs 0.034 of Subcatchment 285: Basin 4 Runoff Area=14.750 at 100.00% Impervious Runoff Depth=3.57" Tc=5.0 min CN=98 Runoff=0.31 cfs 0.101 of Subcatchment 295: Basin 3 Runoff Area=13.035 at 100.00% Impervious Runoff Depth=3.57" Tc=5.0 min CN=98 Runoff=0.27 cfs 0.089 of Subcatchment 305: Basin 2 Runoff Area=10.612 at 100.00% Impervious Runoff Depth=3.57" Tc=5.0 min CN=98 Runoff=0.22 cfs 0.072 of Subcatchment 445: Basin 6 Runoff Area=3,020 at 100.00% Impervious Runoff Depth=3.57" Tc=5.Omin CN=98 Runoff=0.06ds 0.021 of Pond 2P: (new Pond) Peak EIev=447.58' Inflow=0.06 cfs 0.021 of 8.0" Round Culven n=0.011 L=54.0' S=0.0454'f Outflow=0.06 cfs 0.021 of Pond 17P: (new Pond) Peak EIev=446.37' Inflow=0.22 cfs 0.072 of 8.0" Round Culven n=0.011 L=180.0' S=0.0117'/' Outflow=0.22ds 0.072 of Pond 18P: (new Pond) Peak EIev=446.66' Inflow=0.22 cfs 0.072 of 8.0" Round Culven n=0.011 L=30.0' S=0.0050 V Outflow=0.22 cfs 0.072 of Pond 19P: (new Pond) Peak EIev=446.61' Inflow=0.22 cfs 0.072 of 8.0" Round Culven n=0.011 L=42.0' S=0.0060 V Outflow=0.22 cfs 0.072 of Pond 38P: Aggregate Peak EIev=443.06' Storage=1,051 Cf Inflow=0.65 cfs 0.255 of Outflow=0.24 cfs 0.255 of Pond 41 P: Pond Peak EIev=445.39' Storage=3,358 cf Inflow=1.02 cfs 0.333 of Primary=0.00 cfs 0.000 of Secondary=0.22 cfs 0.333 of Outflow=0.22 cfs 0.333 of Pond 42P: Pond Peak EIev=445.28' Storage=158 cf Inflow=0.10 cfs 0.034 of Primary=0.00 cfs 0.000 of Secondary=0.04 cfs 0.034 of Outflow=0.04 cfs 0.034 of Pond 43P: Pond Peak Elev=445.24' Storage=1,714 cf Inflow=0.68 cfs 0.221 of Primary=0.56 cfs 0.109 of Secondary=0.05 cfs 0.112 of Outflow=0.61 cfs 0.221 of Design Model Type IA 24 -hr 5 yr Rainfall=3.80" Prepared by Microsoft Printed 4/24/2020 HydroCAD@ 10.00-24 s/n 10784 © 2018 HydroCAD Software Solutions LLC Paae 11 Summary for Subcatchment 4S: Basin 1 Runoff = 0.45 cis @ 7.86 hrs, Volume= 0.149 af, Depth= 3.57" Runoff by SCS TR -20 method, UH=SCS, Weighted -CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type IA 24 -hr 5 yr Rainfall=3.80" 21,844 98 Paved parking, HSG B 21,844 100.00% Impervious Area Tc Length Slope Velocity Capacity Description 5.0 Summary for Subcatchment 26S: Basin Roof Runoff = 0.38 cis @ 7.86 hrs, Volume= 0.123 af, Depth= 3.57" Runoff by SCS TR -20 method, UH=SCS, Weighted -CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type IA 24 -hr 5 yr Rainfall=3.80" Area (sf) CN Description 18,085 98 Paved parking, HSG B 18,085 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Summary for Subcatchment 27S: Basin 5 Runoff = 0.10 cfs @ 7.86 hrs, Volume= 0.034 af, Depth= 3.57" Runoff by SCS TR -20 method, UH=SCS, Weighted -CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type IA 24 -hr 5 yr Rainfall=3.80" 4,990 98 Paved parking, HSG B 4,990 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Design Model Type IA 24 -hr 5 yr Rainfall=3.80" Prepared by Microsoft Printed 4/24/2020 HydroCAD@ 10.00-24 s/n 10784 © 2018 HydroCAD Software Solutions LLC Paae 12 Summary for Subcatchment 28S: Basin 4 Runoff = 0.31 cis@ 7.86 hrs, Volume= 0.101 af, Depth= 3.57" Runoff by SCS TR -20 method, UH=SCS, Weighted -CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type IA 24 -hr 5 yr Rainfall=3.80" 14,750 98 Paved parking, HSG B 14,750 100.00% Impervious Area Tc Length Slope Velocity Capacity Description 5.0 Summary for Subcatchment 29S: Basin 3 Runoff = 0.27 cis @ 7.86 hrs, Volume= 0.089 af, Depth= 3.57" Runoff by SCS TR -20 method, UH=SCS, Weighted -CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type IA 24 -hr 5 yr Rainfall=3.80" Area (sf) CN Description 13,035 98 Paved parking, HSG B 13,035 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Summary for Subcatchment 30S: Basin 2 Runoff = 0.22 cfs @ 7.86 hrs, Volume= 0.072 af, Depth= 3.57" Runoff by SCS TR -20 method, UH=SCS, Weighted -CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type IA 24 -hr 5 yr Rainfall=3.80" 10,612 98 Paved parking, HSG B 10,612 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Design Model Type IA 24 -hr 5 yr Rainfall=3.80" Prepared by Microsoft Printed 4/24/2020 HydroCAD@ 10.00-24 s/n 10784 02018 HydroCAD Software Solutions LLC Paae 13 Summary for Subcatchment 44S: Basin 6 Runoff = 0.06 cfs @ 7.86 hrs, Volume= 0.021 af, Depth= 3.57" Runoff by SCS TR -20 method, UH=SCS, Weighted -CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type IA 24 -hr 5 yr Rainfall=3.80" 3,020 98 Paved parking, HSG B 3,020 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Summary for Pond 213: (new Pond) Inflow Area = 0.069 ac,100.00% Impervious, Inflow Depth = 3.57" for 5 yr event Inflow = 0.06 cfs @ 7.86 hrs, Volume= 0.021 of Outflow = 0.06 cfs @ 7.86 hrs, Volume= 0.021 af, Atten= 0%, Lag= 0.0 min Primary = 0.06 cfs @ 7.86 hrs, Volume= 0.021 of Routing by Dyn-Slor-Ind method, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 447.58'@ 7.86 hrs Flood Elev= 477.30' Device Routing Invert Outlet Devices #1 Primary 447.45' 8.0" Round Culvert L= 54.0' Ke= 0.500 Inlet/ Outlet Invert= 447.45'/445.00' S=0.0454/' Cc= 0.900 n= 0.011, Flow Area= 0.35 sf Primary OutFlow Max=0.06 cfs @ 7.86 hrs HW=447.58' TW=444.98' (Dynamic Tailwater) 1=Culvert (Inlet Controls 0.06 cfs @ 1.25 fps) Summary for Pond 17P: (new Pond) Inflow Area = 0.244 ac,100.00% Impervious, Inflow Depth = 3.57" for 5 yr event Inflow = 0.22 cfs @ 7.86 hrs, Volume= 0.072 of Outflow = 0.22 cfs @ 7.86 hrs, Volume= 0.072 af, Atten= 0%, Lag= 0.0 min Primary = 0.22 cfs @ 7.86 hrs, Volume= 0.072 of Routing by Dyn-Stor-Ind method, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 446.37'@ 7.88 hrs Flood Elev= 477.30' Device Routing Invert Outlet Devices #1 Primary 446.10' 8.0" Round Culvert L= 180.0' Ke= 0.500 Inlet /Outlet Invert= 446.10'/444.00' S=0.0117'/' Cc= 0.900 n= 0.011, Flow Area= 0.35 sf Design Model Type IA 24 -hr 5 yr Rainfall=3.80" Prepared by Microsoft Printed 4/24/2020 HydroCAD@ 10.00-24 s/n 10784 02018 HydroCAD Software Solutions LLC Paae 14 Primary OutFlow Max=0.22 cfs @ 7.86 hrs HW=446.37' TW=445.21' (Dynamic Tailwater) 1=Culvert (Outlet Controls 0.22 cfs @ 2.42 fps) Summary for Pond 18P: (new Pond) Inflow Area = 0.244 ac,100.00 % Impervious, Inflow Depth = 3.57" for 5 yr event Inflow = 0.22 cfs @ 7.86 hrs, Volume= 0.072 of Outflow = 0.22 cfs @ 7.86 hrs, Volume= 0.072 af, Atten= 0%, Lag= 0.0 min Primary = 0.22 cfs @ 7.86 hrs, Volume= 0.072 of Routing by Dyn-Stor-Ind method, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 446.66'@ 7.86 hrs Device Routing Invert Outlet Devices #1 Primary 446.15' 8.0" Round Culvert L= 30.0' Ke= 0.500 Inlet /Outlet Invert= 446.15'/446.00' S=0.0050'/' Cc= 0.900 n= 0.011, Flow Area= 0.35 sf Primary OutFlow Max=0.22 cfs @ 7.86 hrs HW=446.66' TW=446.61' (Dynamic Tailwater) 1-11 =Culvert (Outlet Controls 0.22 cfs @ 1.07 fps) Summary for Pond 19P: (new Pond) Inflow Area = 0.244 ac,100.00% Impervious, Inflow Depth = 3.57" for 5 yr event Inflow = 0.22 cfs @ 7.86 hrs, Volume= 0.072 of Outflow = 0.22 cfs @ 7.86 hrs, Volume= 0.072 af, Atten= 0%, Lag= 0.0 min Primary = 0.22 cfs @ 7.86 hrs, Volume= 0.072 of Routing by Dyn-Stor-Ind method, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 446.61'@ 7.86 hrs Device Routing Invert Outlet Devices #1 Primary 446.30' 8.0" Round Culvert L= 42.0' Ke= 0.500 Inlet /Outlet Invert= 446.30'/446.05' S= 0.0060'P Cc= 0.900 n= 0.011, Flow Area= 0.35 sf Primary OutFlow Max=0.22 cfs @ 7.86 hrs HW=446.61' TW=446.37' (Dynamic Tailwater) 1=Culvert (Outlet Controls 0.22 cfs @ 2.02 fps) Summary for Pond 3813: Aggregate Inflow Area = 0.860 ac,100.00% Impervious, Inflow Depth > 3.56" for 5 yr event Inflow = 0.65 cfs @ 8.04 hrs, Volume= 0.255 of Outflow = 0.24 cfs @ 7.54 hrs, Volume= 0.255 af, Atten= 62%, Lag= 0.0 min Discarded = 0.24 cfs @ 7.54 hrs, Volume= 0.255 of Routing by Dyn-Scor-Ind method, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 443.06'@ 9.09 hrs Surf.Area= 3,000 sf Storage= 1,051 cf Plug -Flow detention time= 19.2 min calculated for 0.255 of (100% of inflow) Design Modei Type IA 24 -hr 5 yr Rainfall=3.80" Prepared by Microsoft Printed 4/24/2020 HydroCAD@ 10.00-24 s/n 10784 02018 HydroCAD Software Solutions LLC Paae 15 Center -of -Mass det. time= 19.1 min ( 870.7 - 851.5) Volume Invert Avail.Storaae Storage Description #1 442.00' 1,980 cf Custom Stage Data (Prismatic) Listed below (Recalc) 6,000 cf Overall x 33.0% Voids Elevation Surf.Area Inc.Store Cum.Store (feet) (sq -ft) (cubic -feet) (cubic -feet) 442.00 3,000 0 0 444.00 3,000 6,000 6,000 Device Routing Invert Outlet Devices #1 Discarded 442.00' 3.500 in/hr Exfiltration over Surface area Phase -In= 0.01' Discarded OutFlow Max=0.24 cfs @ 7.54 hrs HW=442.02' (Free Discharge) L7=Exfiltration (Exfiltration Controls 0.24 cfs) Summary for Pond 41 P: Pond Inflow Area = 1.122 ac,100.00% Impervious, Inflow Depth = 3.57" for 5 yr event Inflow = 1.02 cfs @ 7.86 hrs, Volume= 0.333 of Outflow = 0.22 cfs @ 10.05 hrs, Volume= 0.333 af, Atten= 79%, Lag= 131.8 min Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 of Secondary = 0.22 cfs @ 10.05 hrs, Volume= 0.333 of Routing by Dyn-Stor-Ind method, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 445.39'@ 10.05 hrs Surf.Area= 3,771 sf Storage= 3,358 cf Plug -Flow detention time= 156.0 min calculated for 0.333 of (1000/. of inflow) Center -of -Mass det. time= 156.0 min ( 816.1 - 660.1 ) Volume Invert Avail.Storage Storage Description #1 444.25' 8,449 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq -ft) (cubic -feet) (cubic -feet) 444.25 2,140 0 0 446.50 5,370 8,449 8,449 Device Routing Invert Outlet Devices #1 Primary 448.50' 2.0' long x 0.50' rise Sharp -Crested Rectangular Weir 2 End Contraction(s) 1.0' Crest Height #2 Secondary 444.25' 2.500 in/hr Exfiltration over Surface area Phase -In= 0.01' Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=444.25' (Free Discharge) 1-11 =Sharp -Crested Rectangular Weir ( Controls 0.00 cfs) Secondary OutFlow Max=0.22 cfs @ 10.05 hrs HW=445.39' (Free Discharge) 2=Exfiltration (Exfiltration Controls 0.22 cfs) Design Model Type IA 24 -hr 5 yr Rainfall=3.80" Prepared by Microsoft Printed 4/24/2020 HydroCAD@ 10.00-24 s/n 10784 02018 HydroCAD Software Solutions LLC Paae 16 Summary for Pond 42P: Pond Inflow Area = 0.115 ac,100.00% Impervious, Inflow Depth = 3.57" for 5 yr event Inflow = 0.10 cfs @ 7.86 hrs, Volume= 0.034 of Outflow = 0.04 cfs @ 8.74 hrs, Volume= 0.034 af, Atten= 65%, Lag= 53.1 min Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 of Secondary = 0.04 cfs @ 8.74 hrs, Volume= 0.034 of Routing by Dyn-Stor-Ind method, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 445.28'@ 8.74 hrs Surf.Area= 631 sf Storage= 158 cf Plug -Flow detention time= 20.7 min calculated for 0.034 of (100% of inflow) Center -of -Mass det. time= 20.7 min ( 680.8 - 660.1 ) Volume Invert Avail.Storage Storage Description #1 445.00' 1,940 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq -ft) (cubic -feet) (cubic -feet) 445.00 500 0 0 447.00 1,440 1,940 1,940 Device Routing Invert Outlet Devices #1 Primary 446.50' 2.0' long x 0.50' rise Sharp -Crested Rectangular Weir 2 End Contraction(s) 1.0' Crest Height #2 Secondary 445.00' 2.500 in/hr Pxdiltration over Surface area Phase -In= 0.01' Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=445.00' TW=442.00' (Dynamic Tailwater) t1 =Sharp -Crested Rectangular Weir ( Controls 0.00 cfs) Secondary OutFlow Max=0.04 cfs @ 8.74 hrs HW=445.28' TW=443.03' (Dynamic Tailwater) 2=Exfiltration (Exfiltration Controls 0.04 cfs) Summary for Pond 43P: Pond Inflow Area = 0.745 ac,100.00% Impervious, Inflow Depth = 3.57" for 5 yr event Inflow = 0.68 cfs @ 7.86 hrs, Volume= 0.221 of Outflow = 0.61 cfs @ 8.04 hrs, Volume= 0.221 af, Atten= 9%, Lag= 10.8 min Primary = 0.56 cfs @ 8.04 hrs, Volume= 0.109 of Secondary = 0.05 cfs @ 8.04 hrs, Volume= 0.112 of Routing by Dyn-Stor-Ind method, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 445.24'@ 8.04 hrs Surf.Area= 1,420 sf Storage= 1,714 cf Plug -Flow detention time= 218.5 min calculated for 0.221 of (1000/. of inflow) Center -of -Mass det. time= 217.7 min ( 877.8 - 660.1 ) Volume Invert Avail.Storage Storage Description #1 443.50' 2,100 cf Custom Stage Data (Prismatic) Listed below (Recalc) Design Nbclei Type IA 24-hr 5 yr Rainfall=3.80" Prepared by Microsoft Printed 4/24/2020 HWroCAD®10.00-24 s/n 10784 02018 HydroCAD Software Solutions LLC Pace 17 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 443.50 550 0 0 445.50 1,550 2,100 2,100 Device Routing Invert Outlet Devices #1 Primary 445.00' 2.0' long x 0.50' rise Sharp-Crested Rectangular Weir 2 End Contraction(s) 1.0' Crest Height #2 Secondary 443.50' 1.500 in/hr Exfiltration over Surface area Phase-In= 0.01' #3 Device 1 444.00' 8.0" Round Culvert L= 115.0' Ke= 0.500 Inlet/ Outlet Invert= 444.00'/443.00' S=0.0087'/' Cc= 0.900 n= 0.011, Flow Area= 0.35 sf Primary OutFlow Max-0.56 cfs @ 8.04 hrs HW=445.24' TW=442.56' (Dynamic Tailwater) 't'114harp-Crested Rectangular Weir (Passes 0.56 cfs of 0.77 cfs potential flow) L3=Culvert (Outlet Controls 0.56 cfs @ 1.61 fps) Secondary OutFlow Max=0.05 cfs @ 8.04 hrs HW=445.24' TW=442.56' (Dynamic Tailwater) 2=Exfiltration (Exfiltration Controls 0.05 cfs) Design Model Type IA 24 -hr 10 yr Rainfall=4.30" Prepared by Microsoft Printed 4/24/2020 HydroCADO 10.00-24 s/n 10784 02018 HydroCAD Software Solutions LLC Pace 18 Time span=0.00-36.00 hrs, dt=0.01 hrs, 3601 points x 2 Runoff by SCS TR -20 method, UH=SCS, Weighted -CN Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method Subcatchment 4S: Basin 1 Runoff Area=21.844 at 100.00%Impervious Runoff Depth=4.06" Tc=5.0 min CN=98 Runoff=0.52 cfs 0.170 of Subcatchment 265: Basin Roof Runoff Area=18.085 at 100.00%Impervious Runoff Depth=4.06" Tc=5.0 min CN=98 Runoff=0.43 cfs 0.141 of Subcatchment 275: Basin 5 Runoff Area=4,990 at 100.00%Impervious Runoff Depth=4.06" Tc=5.0 min CN=98 Runoff=0.12 cfs 0.039 of Subcatchment 285: Basin 4 Runoff Area=14.750 at 100.00% Impervious Runoff Depth=4.06" Tc=5.0 min CN=98 Runoff=0.35 cfs 0.115 of Subcatchment 295: Basin 3 Runoff Area=13.035 at 100.00% Impervious Runoff Depth=4.06" Tc=5.0 min CN=98 Runoff=0.31 cfs 0.101 of Subcatchment 305: Basin 2 Runoff Area=10.612 at 100.00% Impervious Runoff Depth=4.06" Tc=5.0 min CN=98 Runoff=0.25 cfs 0.083 of Subcatchment 445: Basin 6 Runoff Area=3,020 at 100.00% Impervious Runoff Depth=4.06" Tc=5.0 min CN=98 Runoff=0.07 cfs 0.023 of Pond 2P: (new Pond) Peak Elev=447.59' Inflow=0.07 cfs 0.023 of 8.0" Round Culven n=0.011 L=54.0' S=0.0454'f Outflow=0.07 cfs 0.023 of Pond 17P: (new Pond) Peak Elev=446.39' Inflow=0.25 cfs 0.083 of 8.0" Round Culven n=0.011 L=180.0' S=0.0117'/' Outflow=0.25ds 0.083 of Pond 18P: (new Pond) Peak Elev=446.69' Inflow=0.25 cfs 0.083 of 8.0" Round Culven n=0.011 L=30.0' S=0.0050'f Outflow=0.25 cfs 0.083 of Pond 19P: (new Pond) Peak Elev=446.64' Inflow=0.25 cfs 0.083 of 8.0" Round Culven n=0.011 L=42.0' S=0.0060'f Outflow=0.25 cfs 0.083 of Pond 38P: Aggregate Peak Elev=443.42' Storage=1,403 cf Inflow=0.71 cfs 0.291 of Outflow=0.24 cfs 0.291 of Pond 41 P: Pond Peak Elev=445.59' Storage=4,156 cf Inflow=1.16 cfs 0.380 of Primary=0.00 cfs 0.000 of Secondary=0.24 cfs 0.380 of Outflow=0.24 cfs 0.380 of Pond 42P: Pond Peak Elev=445.35' Storage=202 cf Inflow=0.12 cfs 0.039 of Primary=0.00 cfs 0.000 of Secondary=0.04 cfs 0.039 of Outflow=0.04 cfs 0.039 of Pond 43P: Pond Peak Elev=445.29' Storage=1,792 cf Inflow=0.77 cfs 0.252 of Primary=0.62 cfs 0.139 of Secondary=0.05 cfs 0.113 of Outflow=0.67 cfs 0.252 of Design Model Type lA 24 -hr 10 yr Rainfall=4.30" Prepared by Microsoft Printed 4/24/2020 HydroCAD@ 10.00-24 s/n 10784 © 2018 HydroCAD Software Solutions LLC Paae 19 Summary for Subcatchment 4S: Basin 1 Runoff = 0.52 cis @ 7.85 hrs, Volume= 0.170 af, Depth= 4.06" Runoff by SCS TR -20 method, UH=SCS, Weighted -CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type IA 24 -hr 10 yr Rainfall=4.30" 21,844 98 Paved parking, HSG B 21,844 100.00% Impervious Area Tc Length Slope Velocity Capacity Description 5.0 Summary for Subcatchment 26S: Basin Roof Runoff = 0.43 cis @ 7.85 hrs, Volume= 0.141 af, Depth= 4.06" Runoff by SCS TR -20 method, UH=SCS, Weighted -CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type IA 24 -hr 10 yr Rainfall=4.30" Area (sf) CN Description 18,085 98 Paved parking, HSG B 18,085 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Summary for Subcatchment 27S: Basin 5 Runoff = 0.12 cfs @ 7.85 hrs, Volume= 0.039 af, Depth= 4.06" Runoff by SCS TR -20 method, UH=SCS, Weighted -CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type IA 24 -hr 10 yr Rainfall=4.30" 4,990 98 Paved parking, HSG B 4,990 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Design Model Type lA 24 -hr 10 yr Rainfall=4.30" Prepared by Microsoft Printed 4/24/2020 HydroCAD@ 10.00-24 s/n 10784 © 2018 HydroCAD Software Solutions LLC Paae 20 Summary for Subcatchment 28S: Basin 4 Runoff = 0.35 cis @ 7.85 hrs, Volume= 0.115 af, Depth= 4.06" Runoff by SCS TR -20 method, UH=SCS, Weighted -CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type IA 24 -hr 10 yr Rainfall=4.30" 14,750 98 Paved parking, HSG B 14,750 100.00% Impervious Area Tc Length Slope Velocity Capacity Description 5.0 Summary for Subcatchment 29S: Basin 3 Runoff = 0.31 cis@ 7.85 hrs, Volume= 0.101 af, Depth= 4.06" Runoff by SCS TR -20 method, UH=SCS, Weighted -CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type IA 24 -hr 10 yr Rainfall=4.30" Area (sf) CN Description 13,035 98 Paved parking, HSG B 13,035 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Summary for Subcatchment 30S: Basin 2 Runoff = 0.25 cfs @ 7.85 hrs, Volume= 0.083 af, Depth= 4.06" Runoff by SCS TR -20 method, UH=SCS, Weighted -CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type IA 24 -hr 10 yr Rainfall=4.30" 10,612 98 Paved parking, HSG B 10,612 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Design Model Type lA 24 -hr 10 yr Rainfall=4.30" Prepared by Microsoft Printed 4/24/2020 HydroCAD@ 10.00-24 s/n 10784 © 2018 HydroCAD Software Solutions LLC Paae 21 Summary for Subcatchment 44S: Basin 6 Runoff = 0.07 cfs @ 7.85 hrs, Volume= 0.023 af, Depth= 4.06" Runoff by SCS TR -20 method, UH=SCS, Weighted -CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type IA 24 -hr 10 yr Rainfall=4.30" 3,020 98 Paved parking, HSG B 3,020 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Summary for Pond 213: (new Pond) Inflow Area = 0.069 ac,100.00% Impervious, Inflow Depth = 4.06" for 10 yr event Inflow = 0.07 cfs @ 7.85 hrs, Volume= 0.023 of Outflow = 0.07 cfs @ 7.85 hrs, Volume= 0.023 af, Atten= 0%, Lag= 0.0 min Primary = 0.07 cfs @ 7.85 hrs, Volume= 0.023 of Routing by Dyn-Slor-Ind method, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 447.59'@ 7.85 hrs Flood Elev= 477.30' Device Routing Invert Outlet Devices #1 Primary 447.45' 8.0" Round Culvert L= 54.0' Ke= 0.500 Inlet /Outlet Invert= 447.45'/445.00' S=0.0454/' Cc= 0.900 n= 0.011, Flow Area= 0.35 sf Primary OutFlow Max=0.07 cfs @ 7.85 hrs HW=447.59' TW=445.13' (Dynamic Tailwater) 1=Culvert (Inlet Controls 0.07 cfs @ 1.29 fps) Summary for Pond 17P: (new Pond) Inflow Area = 0.244 ac,100.00% Impervious, Inflow Depth = 4.06" for 10 yr event Inflow = 0.25 cfs @ 7.85 hrs, Volume= 0.083 of Outflow = 0.25 cfs @ 7.85 hrs, Volume= 0.083 af, Atten= 0%, Lag= 0.0 min Primary = 0.25 cfs @ 7.85 hrs, Volume= 0.083 of Routing by Dyn-Stor-Ind method, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 446.39'@ 7.89 hrs Flood Elev= 477.30' Device Routing Invert Outlet Devices #1 Primary 446.10' 8.0" Round Culvert L= 180.0' Ke= 0.500 Inlet /Outlet Invert= 446.10'/444.00' S=0.0117'/' Cc= 0.900 n= 0.011, Flow Area= 0.35 sf Design Model Type IA 24 -hr 10 yr Rainfall=4.30" Prepared by Microsoft Printed 4/24/2020 HydroCAD@ 10.00-24 s/n 10784 02018 HydroCAD Software Solutions LLC Paae 22 Primary OutFlow Max=0.25 cfs @ 7.85 hrs HW=446.39' TW=445.25' (Dynamic Tailwater) 1=Culvert (Outlet Controls 0.25 cfs @ 2.49 fps) Summary for Pond 18P: (new Pond) Inflow Area = 0.244 ac,100.00 % Impervious, Inflow Depth = 4.06" for 10 yr event Inflow = 0.25 cfs @ 7.85 hrs, Volume= 0.083 of Outflow = 0.25 cfs @ 7.85 hrs, Volume= 0.083 af, Atten= 0%, Lag= 0.0 min Primary = 0.25 cfs @ 7.85 hrs, Volume= 0.083 of Routing by Dyn-Stor-Ind method, Time Span= 0.00-36.00 hrs, of= 0.01 hrs / 2 Peak Elev= 446.69'@ 7.86 hrs Device Routing Invert Outlet Devices #1 Primary 446.15' 8.0" Round Culvert L= 30.0' Ke= 0.500 Inlet /Outlet Invert= 446.15'/446.00' S=0.0050'/' Cc= 0.900 n= 0.011, Flow Area= 0.35 sf Primary OutFlow Max=0.25 cfs @ 7.85 hrs HW=446.69' TW=446.64' (Dynamic Tailwater) 1­1=Culvert (Outlet Controls 0.25 cfs @ 1.14 fps) Summary for Pond 19P: (new Pond) Inflow Area = 0.244 ac,100.00% Impervious, Inflow Depth = 4.06" for 10 yr event Inflow = 0.25 cfs @ 7.85 hrs, Volume= 0.083 of Outflow = 0.25 cfs @ 7.85 hrs, Volume= 0.083 af, Atten= 0%, Lag= 0.0 min Primary = 0.25 cfs @ 7.85 hrs, Volume= 0.083 of Routing by Dyn-Stor-Ind method, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 446.64'@ 7.86 hrs Device Routing Invert Outlet Devices #1 Primary 446.30' 8.0" Round Culvert L= 42.0' Ke= 0.500 Inlet /Outlet Invert= 446.30'/446.05' S= 0.0060'P Cc= 0.900 n= 0.011, Flow Area= 0.35 sf Primary OutFlow Max=0.25 cfs @ 7.85 hrs HW=446.64' TW=446.39' (Dynamic Tailwater) 1=Culvert (Outlet Controls 0.25 cfs @ 2.08 fps) Summary for Pond 3813: Aggregate Inflow Area = 0.860 ac,100.00% Impervious, Inflow Depth > 4.06" for 10 yr event Inflow = 0.71 cfs@ 8.05 hrs, Volume= 0.291 of Outflow = 0.24 cfs @ 7.35 hrs, Volume= 0.291 at, Atten= 66%, Lag= 0.0 min Discarded = 0.24 cfs @ 7.35 hrs, Volume= 0.291 of Routing by Dyn-Stor-Ind method, Time Span= 0.00-36.00 hrs, of= 0.01 hrs / 2 Peak Elev= 443.42'@9.32 hrs Surf.Area= 3,000 sf Storage= 1,403 cf Plug -Flow detention time= 29.5 min calculated for 0.291 of (100% of inflow) Design Modei Type IA 24 -hr 10 yr Rainfall=4.30" Prepared by Microsoft Printed 4/24/2020 HydroCAD@ 10.00-24 s/n 10784 02018 HydroCAD Software Solutions LLC Paae 23 Center -of -Mass det. time= 29.4 min ( 859.9 - 830.5) Volume Invert Avail.Storaae Storage Description #1 442.00' 1,980 cf Custom Stage Data (Prismatic) Listed below (Recalc) 6,000 cf Overall x 33.0% Voids Elevation Surf.Area Inc.Store Cum.Store (feet) (sq -ft) (cubic -feet) (cubic -feet) 442.00 3,000 0 0 444.00 3,000 6,000 6,000 Device Routing Invert Outlet Devices #1 Discarded 442.00' 3.500 in/hr Exfiltration over Surface area Phase -In= 0.01' Discarded OutFlow Max=0.24 cfs @ 7.35 hrs HW=442.02' (Free Discharge) L7=Exfiltration (Exfiltration Controls 0.24 cfs) Summary for Pond 41 P: Pond Inflow Area = 1.122 ac,100.00°/, Impervious, Inflow Depth = 4.06" for 10 yr event Inflow = 1.16 cfs @ 7.85 hrs, Volume= 0.380 of Outflow = 0.24 cfs @ 10.24 hrs, Volume= 0.380 af, Atten= 80%, Lag= 143.2 min Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 of Secondary = 0.24 cfs @ 10.24 hrs, Volume= 0.380 of Routing by Dyn-Stor-Ind method, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 445.59'@ 10.24 hrs Surf.Area= 4,063 sf Storage= 4,156 cf Plug -Flow detention time= 190.0 min calculated for 0.380 of (1000% of inflow) Center -of -Mass det. time= 190.0 min ( 847.2 - 657.2) Volume Invert Avail.Storage Storage Description #1 444.25' 8,449 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq -ft) (cubic -feet) (cubic -feet) 444.25 2,140 0 0 446.50 5,370 8,449 8,449 Device Routing Invert Outlet Devices #1 Primary 448.50' 2.0' long x 0.50' rise Sharp -Crested Rectangular Weir 2 End Contraction(s) 1.0' Crest Height #2 Secondary 444.25' 2.500 in/hr Exfiltration over Surface area Phase -In= 0.01' Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=444.25' (Free Discharge) 1-11 =Sharp -Crested Rectangular Weir ( Controls 0.00 cfs) Secondary OutFlow Max=0.24 cfs @ 10.24 hrs HW=445.59' (Free Discharge) 2=Exfiltration (Exfiltration Controls 0.24 cfs) Design Model Type IA 24 -hr 10 yr Rainfall=4.30" Prepared by Microsoft Printed 4/24/2020 HydroCAD@ 10.00-24 s/n 10784 02018 HydroCAD Software Solutions LLC Paae 24 Summary for Pond 42P: Pond Inflow Area = 0.115 ac,100.00% Impervious, Inflow Depth = 4.06" for 10 yr event Inflow = 0.12 cfs @ 7.85 hrs, Volume= 0.039 of Outflow = 0.04 cfs @ 8.86 hrs, Volume= 0.039 af, Atten= 67%, Lag= 60.4 min Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 of Secondary = 0.04 cfs @ 8.86 hrs, Volume= 0.039 of Routing by Dyn-Stor-Ind method, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 445.35'@8.86 hrs Surf.Area= 663 sf Storage= 202 cf Plug -Flow detention time= 27.4 min calculated for 0.039 of (100% of inflow) Center -of -Mass det. time= 27.4 min ( 684.6 - 657.2) Volume Invert Avail.Storage Storage Description #1 445.00' 1,940 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq -ft) (cubic -feet) (cubic -feet) 445.00 500 0 0 447.00 1,440 1,940 1,940 Device Routing Invert Outlet Devices #1 Primary 446.50' 2.0' long x 0.50' rise Sharp -Crested Rectangular Weir 2 End Contraction(s) 1.0' Crest Height #2 Secondary 445.00' 2.500 in/hr Pxdiltration over Surface area Phase -In= 0.01' Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=445.00' TW=442.00' (Dynamic Tailwater) t1 =Sharp -Crested Rectangular Weir ( Controls 0.00 cfs) Secondary OutFlow Max=0.04 cfs @ 8.86 hrs HW=445.35' TW=443.37' (Dynamic Tailwater) 2=Exfiltration (Exfiltration Controls 0.04 cfs) Summary for Pond 43P: Pond Inflow Area = 0.745 ac,100.00% Impervious, Inflow Depth = 4.06" for 10 yr event Inflow = 0.77 cfs @ 7.85 hrs, Volume= 0.252 of Outflow = 0.67 cfs @ 8.04 hrs, Volume= 0.252 af, Atten= 12%, Lag= 11.4 min Primary = 0.62 cfs @ 8.04 hrs, Volume= 0.139 of Secondary = 0.05 cfs @ 8.04 hrs, Volume= 0.113 of Routing by Dyn-Stor-Ind method, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 445.29'@ 8.04 hrs Surf.Area= 1,447 sf Storage= 1,792 cf Plug -Flow detention time= 196.7 min calculated for 0.252 of (1000/0 of inflow) Center -of -Mass det. time= 195.7 min ( 852.9 - 657.2) Volume Invert Avail.Storage Storage Description #1 443.50' 2,100 cf Custom Stage Data (Prismatic) Listed below (Recalc) Design Nbclei Type IA 24-hr 10 yr Rainfall=4.30" Prepared by Microsoft Printed 4/24/2020 HWroCAD®10.00-24 s/n 10784 02018 HydroCAD Software Solutions LLC Pace 25 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 443.50 550 0 0 445.50 1,550 2,100 2,100 Device Routing Invert Outlet Devices #1 Primary 445.00' 2.0' long x 0.50' rise Sharp-Crested Rectangular Weir 2 End Contraction(s) 1.0' Crest Height #2 Secondary 443.50' 1.500 in/hr Exfiltration over Surface area Phase-In= 0.01' #3 Device 1 444.00' 8.0" Round Culvert L= 115.0' Ke= 0.500 Inlet/ Outlet Invert= 444.00'/443.00' S=0.0087'/' Cc= 0.900 n= 0.011, Flow Area= 0.35 sf Primary OutFlow Max-0.62 cfs @ 8.04 hrs HW=445.29' TW=442.70' (Dynamic Tailwater) 't'114harp-Crested Rectangular Weir (Passes 0.62 cfs of 1.05 cfs potential flow) L3=Culvert (Outlet Controls 0.62 cfs @ 1.79 fps) Secondary OutFlow Max=0.05 cfs @ 8.04 hrs HW=445.29' TW=442.70' (Dynamic Tailwater) 2=Exfiltration (Exfiltration Controls 0.05 cfs) Design Model Type IA 24 -hr 25 yr Rainfall=4.80" Prepared by Microsoft Printed 4/24/2020 HydroCADO 10.00-24 s/n 10784 02018 HydroCAD Software Solutions LLC Pace 26 Time span=0.00-36.00 hrs, dt=0.01 hrs, 3601 points x 2 Runoff by SCS TR -20 method, UH=SCS, Weighted -CN Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method Subcatchment 4S: Basin 1 Runoff Area=21.844 at 100.00%Impervious Runoff Depth=4.56" Tc=5.0 min CN=98 Runoff=0.58 cfs 0.191 of Subcatchment 265: Basin Roof Runoff Area=18.085 at 100.00%Impervious Runoff Depth=4.56" Tc=5.0 min CN=98 Runoff=0.48 cfs 0.158 of Subcatchment 275: Basin 5 Runoff Area=4,990 at 100.00%Impervious Runoff Depth=4.56" Tc=5.0 min CN=98 Runoff=0.13 cfs 0.044 of Subcatchment 285: Basin 4 Runoff Area=14.750 at 100.00% Impervious Runoff Depth=4.56" Tc=5.0 min CN=98 Runoff=0.39 cfs 0.129 of Subcatchment 295: Basin 3 Runoff Area=13.035 at 100.00% Impervious Runoff Depth=4.56" Tc=5.0 min CN=98 Runoff=0.34 cfs 0.114 of Subcatchment 305: Basin 2 Runoff Area=10.612 at 100.00% Impervious Runoff Depth=4.56" Tc=5.0 min CN=98 Runoff=0.28 cfs 0.093 of Subcatchment 445: Basin 6 Runoff Area=3,020 at 100.00% Impervious Runoff Depth=4.56" Tc=5.0 min CN=98 Runoff=0.08 cfs 0.026 of Pond 2P: (new Pond) Peak EIev=447.60' Inflow=0.08 cfs 0.026 of 8.0" Round Culven n=0.011 L=54.0' S=0.0454'f Outflow=0.08 cfs 0.026 of Pond 17P: (new Pond) Peak EIev=446.42' Inflow=0.28 cfs 0.093 of 8.0" Round Culven n=0.011 L=180.0' S=0.0117'/' Outflow=0.28cfs 0.093 of Pond 18P: (new Pond) Peak EIev=446.71' Inflow=0.28 cfs 0.093 of 8.0" Round Culven n=0.011 L=30.0' S=0.0050 V Outflow=0.28 cfs 0.093 of Pond 19P: (new Pond) Peak EIev=446.66' Inflow=0.28 cfs 0.093 of 8.0" Round Culven n=0.011 L=42.0' S=0.0060 V Outflow=0.28 cfs 0.093 of Pond 38P: Aggregate Peak EIev=443.82' Storage=1,800 cf Inflow=0.77 cfs 0.327 of Outflow=0.24 cfs 0.327 of Pond 41 P: Pond Peak EIev=445.79' Storage=5,005 cf Inflow=1.29 cfs 0.427 of Primary=0.00 cfs 0.000 of Secondary=0.25 cfs 0.427 of Outflow=0.25 cfs 0.427 of Pond 42P: Pond Peak EIev=445.42' Storage=255 cf Inflow=0.13 cfs 0.044 of Primary=0.00 cfs 0.000 of Secondary=0.04 cfs 0.044 of Outflow=0.04 cfs 0.044 of Pond 43P: Pond Peak EIev=445.35' Storage=1,876 cf Inflow=0.86 cfs 0.283 of Primary=0.68 cfs 0.168 of Secondary=0.05 cfs 0.115 of Oufflow=0.73 cfs 0.283 of Design Model Type IA 24 -hr 25 yr Rainfall=4.80" Prepared by Microsoft Printed 4/24/2020 HydroCAD@ 10.00-24 s/n 10784 © 2018 HydroCAD Software Solutions LLC Paae 27 Summary for Subcatchment 4S: Basin 1 Runoff = 0.58 cis @ 7.85 hrs, Volume= 0.191 af, Depth= 4.56" Runoff by SCS TR -20 method, UH=SCS, Weighted -CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type IA 24 -hr 25 yr Rainfall=4.80" 21,844 98 Paved parking, HSG B 21,844 100.00% Impervious Area Tc Length Slope Velocity Capacity Description 5.0 Summary for Subcatchment 26S: Basin Roof Runoff = 0.48 cis @ 7.85 hrs, Volume= 0.158 af, Depth= 4.56" Runoff by SCS TR -20 method, UH=SCS, Weighted -CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type IA 24 -hr 25 yr Rainfall=4.80" Area (sf) CN Description 18,085 98 Paved parking, HSG B 18,085 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Summary for Subcatchment 27S: Basin 5 Runoff = 0.13 cfs @ 7.85 hrs, Volume= 0.044 af, Depth= 4.56" Runoff by SCS TR -20 method, UH=SCS, Weighted -CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type IA 24 -hr 25 yr Rainfall=4.80" 4,990 98 Paved parking, HSG B 4,990 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Design Model Type IA 24 -hr 25 yr Rainfall=4.80" Prepared by Microsoft Printed 4/24/2020 HydroCAD@ 10.00-24 s/n 10784 © 2018 HydroCAD Software Solutions LLC Paae 28 Summary for Subcatchment 28S: Basin 4 Runoff = 0.39 cis @ 7.85 hrs, Volume= 0.129 af, Depth= 4.56" Runoff by SCS TR -20 method, UH=SCS, Weighted -CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type IA 24 -hr 25 yr Rainfall=4.80" 14,750 98 Paved parking, HSG B 14,750 100.00% Impervious Area Tc Length Slope Velocity Capacity Description 5.0 Summary for Subcatchment 29S: Basin 3 Runoff = 0.34 cis @ 7.85 hrs, Volume= 0.114 af, Depth= 4.56" Runoff by SCS TR -20 method, UH=SCS, Weighted -CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type IA 24 -hr 25 yr Rainfall=4.80" Area (sf) CN Description 13,035 98 Paved parking, HSG B 13,035 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Summary for Subcatchment 30S: Basin 2 Runoff = 0.28 cfs @ 7.85 hrs, Volume= 0.093 af, Depth= 4.56" Runoff by SCS TR -20 method, UH=SCS, Weighted -CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type IA 24 -hr 25 yr Rainfall=4.80" 10,612 98 Paved parking, HSG B 10,612 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Design Model Type IA 24 -hr 25 yr Rainfall=4.80" Prepared by Microsoft Printed 4/24/2020 HydroCAD@ 10.00-24 s/n 10784 © 2018 HydroCAD Software Solutions LLC Paae 29 Summary for Subcatchment 44S: Basin 6 Runoff = 0.08 cfs @ 7.85 hrs, Volume= 0.026 af, Depth= 4.56" Runoff by SCS TR -20 method, UH=SCS, Weighted -CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type IA 24 -hr 25 yr Rainfall=4.80" 3,020 98 Paved parking, HSG B 3,020 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Summary for Pond 213: (new Pond) Inflow Area = 0.069 ac,100.00% Impervious, Inflow Depth = 4.56" for 25 yr event Inflow = 0.08 cfs @ 7.85 hrs, Volume= 0.026 of Outflow = 0.08 cfs @ 7.85 hrs, Volume= 0.026 af, Atten= 0%, Lag= 0.0 min Primary = 0.08 cfs @ 7.85 hrs, Volume= 0.026 of Routing by Dyn-Slor-Ind method, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 447.60'@ 7.85 hrs Flood Elev= 477.30' Device Routing Invert Outlet Devices #1 Primary 447.45' 8.0" Round Culvert L= 54.0' Ke= 0.500 Inlet /Outlet Invert= 447.45'/445.00' S=0.0454/' Cc= 0.900 n= 0.011, Flow Area= 0.35 sf Primary OutFlow Max=0.08 cfs @ 7.85 hrs HW=447.60' TW=445.28' (Dynamic Tailwater) 1=Culvert (Inlet Controls 0.08 cfs @ 1.33 fps) Summary for Pond 17P: (new Pond) Inflow Area = 0.244 ac,100.00% Impervious, Inflow Depth = 4.56" for 25 yr event Inflow = 0.28 cfs @ 7.85 hrs, Volume= 0.093 of Outflow = 0.28 cfs @ 7.85 hrs, Volume= 0.093 af, Atten= 0%, Lag= 0.0 min Primary = 0.28 cfs @ 7.85 hrs, Volume= 0.093 of Routing by Dyn-Stor-Ind method, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 446.42'@ 7.90 hrs Flood Elev= 477.30' Device Routing Invert Outlet Devices #1 Primary 446.10' 8.0" Round Culvert L= 180.0' Ke= 0.500 Inlet /Outlet Invert= 446.10'/444.00' S=0.0117'/' Cc= 0.900 n= 0.011, Flow Area= 0.35 sf Design Model Type IA 24 -hr 25 yr Rainfall=4.80" Prepared by Microsoft Printed 4/24/2020 HydroCAD@ 10.00-24 s/n 10784 02018 HydroCAD Software Solutions LLC Paae 30 Primary OutFlow Max=0.28 cfs @ 7.85 hrs HW=446.41' TW=445.29' (Dynamic Tailwater) 1=Culvert (Outlet Controls 0.28 cfs @ 2.54 fps) Summary for Pond 18P: (new Pond) Inflow Area = 0.244 ac,100.00 % Impervious, Inflow Depth = 4.56" for 25 yr event Inflow = 0.28 cfs @ 7.85 hrs, Volume= 0.093 of Outflow = 0.28 cfs @ 7.85 hrs, Volume= 0.093 at, Atten= 0%, Lag= 0.0 min Primary = 0.28 cfs @ 7.85 hrs, Volume= 0.093 of Routing by Dyn-Stor-Ind method, Time Span= 0.00-36.00 hrs, of= 0.01 hrs / 2 Peak Elev= 446.71'@ 7.86 hrs Device Routing Invert Outlet Devices #1 Primary 446.15' 8.0" Round Culvert L= 30.0' Ke= 0.500 Inlet /Outlet Invert= 446.15'/446.00' S=0.0050'/' Cc= 0.900 n= 0.011, Flow Area= 0.35 sf Primary OutFlow Max=0.28 cfs @ 7.85 hrs HW=446.71' TW=446.66' (Dynamic Tailwater) 1-11 =Culvert (Outlet Controls 0.28 cfs @ 1.20 fps) Summary for Pond 19P: (new Pond) Inflow Area = 0.244 ac,100.00% Impervious, Inflow Depth = 4.56" for 25 yr event Inflow = 0.28 cfs @ 7.85 hrs, Volume= 0.093 of Outflow = 0.28 cfs @ 7.85 hrs, Volume= 0.093 af, Atten= 0%, Lag= 0.0 min Primary = 0.28 cfs @ 7.85 hrs, Volume= 0.093 of Routing by Dyn-Stor-Ind method, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 446.66'@ 7.87 hrs Device Routing Invert Outlet Devices #1 Primary 446.30' 8.0" Round Culvert L= 42.0' Ke= 0.500 Inlet /Outlet Invert= 446.30'/446.05' S= 0.0060'P Cc= 0.900 n= 0.011, Flow Area= 0.35 sf Primary OutFlow Max=0.28 cfs @ 7.85 hrs HW=446.66' TW=446.41' (Dynamic Tailwater) 1=Culvert (Outlet Controls 0.28 cfs @ 2.13 fps) Summary for Pond 3813: Aggregate Inflow Area = 0.860 ac,100.00% Impervious, Inflow Depth > 4.56" for 25 yr event Inflow = 0.77 cfs @ 8.05 hrs, Volume= 0.327 of Outflow = 0.24 cfs @ 7.12 hrs, Volume= 0.327 af, Atten= 68%, Lag= 0.0 min Discarded = 0.24 cfs @ 7.12 hrs, Volume= 0.327 of Routing by Dyn-Stor-Ind method, Time Span= 0.00-36.00 hrs, of= 0.01 hrs / 2 Peak Elev= 443.82'@9.68 hrs Surf.Area= 3,000 sf Storage= 1,800 cf Plug -Flow detention time= 43.8 min calculated for 0.326 of (100% of inflow) Design Modei Type IA 24 -hr 25 yr Rainfall=4.80" Prepared by Microsoft Printed 4/24/2020 HydroCAD@ 10.00-24 s/n 10784 02018 HydroCAD Software Solutions LLC Paae 31 Center -of -Mass det. time= 43.7 min ( 857.6 - 813.9) Volume Invert Avail.Storaae Storage Description #1 442.00' 1,980 cf Custom Stage Data (Prismatic) Listed below (Recalc) 6,000 cf Overall x 33.0% Voids Elevation Surf.Area Inc.Store Cum.Store (feet) (sq -ft) (cubic -feet) (cubic -feet) 442.00 3,000 0 0 444.00 3,000 6,000 6,000 Device Routing Invert Outlet Devices #1 Discarded 442.00' 3.500 in/hr Exfiltration over Surface area Phase -In= 0.01' Discarded OutFlow Max=0.24 cfs @ 7.12 hrs HW=442.02' (Free Discharge) L7=Exfiltration (Exfiltration Controls 0.24 cfs) Summary for Pond 41 P: Pond Inflow Area = 1.122 ac,100.00% Impervious, Inflow Depth = 4.56" for 25 yr event Inflow = 1.29 cfs @ 7.85 hrs, Volume= 0.427 of Outflow = 0.25 cfs @ 10.76 hrs, Volume= 0.427 af, Atten= 81%, Lag= 174.1 min Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 of Secondary = 0.25 cfs @ 10.76 hrs, Volume= 0.427 of Routing by Dyn-Stor-Ind method, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 445.79'@ 10.76 hrs Surf.Area= 4,353 sf Storage= 5,005 cf Plug -Flow detention time= 222.7 min calculated for 0.427 of (100% of inflow) Center -of -Mass det. time= 222.7 min ( 877.5 - 654.9) Volume Invert Avail.Storage Storage Description #1 444.25' 8,449 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq -ft) (cubic -feet) (cubic -feet) 444.25 2,140 0 0 446.50 5,370 8,449 8,449 Device Routing Invert Outlet Devices #1 Primary 448.50' 2.0' long x 0.50' rise Sharp -Crested Rectangular Weir 2 End Contraction(s) 1.0' Crest Height #2 Secondary 444.25' 2.500 in/hr Exfiltration over Surface area Phase -In= 0.01' Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=444.25' (Free Discharge) 1-11 =Sharp -Crested Rectangular Weir ( Controls 0.00 cfs) Secondary OutFlow Max=0.25 cfs @ 10.76 hrs HW=445.79' (Free Discharge) 2=Exfiltration (Exfiltration Controls 0.25 cfs) Design Model Type IA 24 -hr 25 yr Rainfall=4.80" Prepared by Microsoft Printed 4/24/2020 HydroCAD@ 10.00-24 s/n 10784 02018 HydroCAD Software Solutions LLC Paae 32 Summary for Pond 42P: Pond Inflow Area = 0.115 ac,100.00% Impervious, Inflow Depth = 4.56" for 25 yr event Inflow = 0.13 cfs @ 7.85 hrs, Volume= 0.044 of Outflow = 0.04 cfs @ 8.96 hrs, Volume= 0.044 af, Atten= 69%, Lag= 66.2 min Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 of Secondary = 0.04 cfs @ 8.96 hrs, Volume= 0.044 of Routing by Dyn-Stor-Ind method, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 445.42'@8.96 hrs Surf.Area= 700 sf Storage= 255 cf Plug -Flow detention time= 36.1 min calculated for 0.044 of (100% of inflow) Center -of -Mass det. time= 36.1 min ( 691.0 - 654.9) Volume Invert Avail.Storage Storage Description #1 445.00' 1,940 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq -ft) (cubic -feet) (cubic -feet) 445.00 500 0 0 447.00 1,440 1,940 1,940 Device Routing Invert Outlet Devices #1 Primary 446.50' 2.0' long x 0.50' rise Sharp -Crested Rectangular Weir 2 End Contraction(s) 1.0' Crest Height #2 Secondary 445.00' 2.500 in/hr Pxdiltration over Surface area Phase -In= 0.01' Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=445.00' TW=442.00' (Dynamic Tailwater) t1 =Sharp -Crested Rectangular Weir ( Controls 0.00 cfs) Secondary OutFlow Max=0.04 cfs @ 8.96 hrs HW=445.42' TW=443.74' (Dynamic Tailwater) 2=Exfiltration (Exfiltration Controls 0.04 cfs) Summary for Pond 43P: Pond Inflow Area = 0.745 ac,100.00% Impervious, Inflow Depth = 4.56" for 25 yr event Inflow = 0.86 cfs @ 7.85 hrs, Volume= 0.283 of Outflow = 0.73 cfs @ 8.05 hrs, Volume= 0.283 af, Atten= 15%, Lag= 11.8 min Primary = 0.68 cfs @ 8.05 hrs, Volume= 0.168 of Secondary = 0.05 cfs @ 8.05 hrs, Volume= 0.115 of Routing by Dyn-Stor-Ind method, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 445.35'@ 8.05 hrs Surf.Area= 1,476 sf Storage= 1,876 cf Plug -Flow detention time= 179.0 min calculated for 0.283 of (1000/0 of inflow) Center -of -Mass det. time= 178.0 min ( 832.8 - 654.9) Volume Invert Avail.Storage Storage Description #1 443.50' 2,100 cf Custom Stage Data (Prismatic) Listed below (Recalc) Design Nbclei Type IA 24-hr 25 yr Rainfall=4.80" Prepared by Microsoft Printed 4/24/2020 HWroCAD®10.00-24 s/n 10784 02018 HydroCAD Software Solutions LLC Pace 33 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 443.50 550 0 0 445.50 1,550 2,100 2,100 Device Routing Invert Outlet Devices #1 Primary 445.00' 2.0' long x 0.50' rise Sharp-Crested Rectangular Weir 2 End Contraction(s) 1.0' Crest Height #2 Secondary 443.50' 1.500 in/hr Exfiltration over Surface area Phase-In= 0.01' #3 Device 1 444.00' 8.0" Round Culvert L= 115.0' Ke= 0.500 Inlet/ Outlet Invert= 444.00'/443.00' S=0.0087'/' Cc= 0.900 n= 0.011, Flow Area= 0.35 sf Primary OutFlow Max-0.68 cfs @ 8.05 hrs HW=445.35' TW=442.86' (Dynamic Tailwater) 't'114harp-Crested Rectangular Weir (Passes 0.68 cfs of 1.37 cfs potential flow) L3=Culvert (Outlet Controls 0.68 cfs @ 1.95 fps) Secondary OutFlow Max=0.05 cfs @ 8.05 hrs HW=445.35' TW=442.86' (Dynamic Tailwater) 2=Exfiltration (Exfiltration Controls 0.05 cfs) Design Nbdel Type IA 24 -hr WO Rainfall=0.83" Prepared by Microsoft Printed 4/24/2020 HydroCADO 10.00-24 s/n 10784 02018 HydroCAD Software Solutions LLC Pace 34 Time span=0.00-36.00 hrs, dt=0.01 hrs, 3601 points x 2 Runoff by SCS TR -20 method, UH=SCS, Weighted -CN Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method Subcatchment 4S: Basin 1 Runoff Area=21.844 at 100.00%Impervious Runoff Depth=0.63" Tc=5.0 min CN=98 Runoff=0.08 ds 0.026 of Subcatchment 265: Basin Roof Runoff Area=18.085 at 100.00%Impervious Runoff Depth=0.63" Tc=5.0 min CN=98 Runoff=0.07 ds 0.022 of Subcatchment 275: Basin 5 Runoff Area=4,990 at 100.00%Impervious Runoff Depth=0.63" Tc=5.0 min CN=98 Runoff=0.02 ds 0.006 of Subcatchment 285: Basin 4 Runoff Area=14.750 at 100.00% Impervious Runoff Depth=0.63" Tc=5.0 min CN=98 Runoff=0.06 ds 0.018 of Subcatchment 295: Basin 3 Runoff Area=13.035 at 100.00% Impervious Runoff Depth=0.63" Tc=5.0 min CN=98 Runoff=0.05 ds 0.016 of Subcatchment 305: Basin 2 Runoff Area=10.612 at 100.00% Impervious Runoff Depth=0.63" Tc=5.0 min CN=98 Runoff=0.04 ds 0.013 of Subcatchment 445: Basin 6 Runoff Area=3,020 at 100.00% Impervious Runoff Depth=0.63" Tc=5.0 min CN=98 Runoff=0.01 ds 0.004 of Pond 2P: (new Pond) Peak Elev=447.51' Inflow=0.01 ds 0.004 of 8.0" Round Culvert n=0.011 L=54.0' S=0.0454'13 Outflow=0.01 ds 0.004 of Pond 17P: (new Pond) Peak Elev=446.21' Inflow=0.04 ds 0.013 of 8.0" RoundCulvert n=0.011 L=180.0' S=0.0117'/' Outflow=0.04cfs 0.013 of Pond 1813: (new Pond) Peak Elev=446.43' Inflow=0.04 cfs 0.013 of 8.0" RoundCulvert n=0.011 L=30.0' S=0.0050'13 Outflow=0.04 cfs 0.013 of Pond 19P: (new Pond) Peak Elev=446.43' Inflow=0.04 cfs 0.013 of 8.0" RoundCulvert n=0.011 L=42.0' S=0.0060'13 Outflow=0.04 cfs 0.013 of Pond 38P: Aggregate Peak EIev=442.00' Storage=2 cf Inflow=0.04 ate 0.045 of Outflow=0.04 ate 0.045 of Pond 41 P: Pond Peak EIev=444.30' Storage=100 cf Inflow=0.18 cfs 0.059 of Primary=0.00 ds 0.000 of Secondary=0.13 ds 0.059 of Outflow=0.13 cfs 0.059 of Pond 42P: Pond Peak EIev=445.01' Storage=3 cf Inflow=0.02 cfs 0.006 of Primary=0.00 ds 0.000 of Secondary=0.02 ds 0.006 of Outflow=0.02 ds 0.006 of Pond 43P: Pond Peak EIev=444.00' Storage=334 cf Inflow=0.12 ds 0.039 of Primary=0.00 cfs 0.000 of Secondary=0.03 cfs 0.039 of Outflow=0.03 cfs 0.039 of Design Model Type /A 24 -hr WO Rainfall=0.83" Prepared by Microsoft Printed 4/24/2020 HydroCAD@ 10.00-24 s/n 10784 © 2018 HydroCAD Software Solutions LLC Paae 35 Summary for Subcatchment 4S: Basin 1 Runoff = 0.08 cis @ 7.89 hrs, Volume= 0.026 af, Depth= 0.63" Runoff by SCS TR -20 method, UH=SCS, Weighted -CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type IA 24 -hr WO Rainfall=0.83" 21,844 98 Paved parking, HSG B 21,844 100.00% Impervious Area Tc Length Slope Velocity Capacity Description 5.0 Summary for Subcatchment 26S: Basin Roof Runoff = 0.07 cis @ 7.89 hrs, Volume= 0.022 af, Depth= 0.63" Runoff by SCS TR -20 method, UH=SCS, Weighted -CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type IA 24 -hr WO Rainfall=0.83" Area (sf) CN Description 18,085 98 Paved parking, HSG B 18,085 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Summary for Subcatchment 27S: Basin 5 Runoff = 0.02 cfs @ 7.89 hrs, Volume= 0.006 af, Depth= 0.63" Runoff by SCS TR -20 method, UH=SCS, Weighted -CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type IA 24 -hr WO Rainfall=0.83" 4,990 98 Paved parking, HSG B 4,990 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Design Model Type /A 24 -hr WO Rainfall=0.83" Prepared by Microsoft Printed 4/24/2020 HydroCAD@ 10.00-24 s/n 10784 © 2018 HydroCAD Software Solutions LLC Paae 36 Summary for Subcatchment 28S: Basin 4 Runoff = 0.06 cis @ 7.89 hrs, Volume= 0.018 af, Depth= 0.63" Runoff by SCS TR -20 method, UH=SCS, Weighted -CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type IA 24 -hr WO Rainfall=0.83" 14,750 98 Paved parking, HSG B 14,750 100.00% Impervious Area Tc Length Slope Velocity Capacity Description 5.0 Summary for Subcatchment 29S: Basin 3 Runoff = 0.05 cis @ 7.89 hrs, Volume= 0.016 af, Depth= 0.63" Runoff by SCS TR -20 method, UH=SCS, Weighted -CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type IA 24 -hr WO Rainfall=0.83" Area (sf) CN Description 13,035 98 Paved parking, HSG B 13,035 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Summary for Subcatchment 30S: Basin 2 Runoff = 0.04 cfs @ 7.89 hrs, Volume= 0.013 af, Depth= 0.63" Runoff by SCS TR -20 method, UH=SCS, Weighted -CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type IA 24 -hr WO Rainfall=0.83" 10,612 98 Paved parking, HSG B 10,612 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Design Model Type /A 24 -hr WO Rainfall=0.83" Prepared by Microsoft Printed 4/24/2020 HydroCAD@ 10.00-24 s/n 10784 © 2018 HydroCAD Software Solutions LLC Paae 37 Summary for Subcatchment 44S: Basin 6 Runoff = 0.01 cfs @ 7.89 hrs, Volume= 0.004 af, Depth= 0.63" Runoff by SCS TR -20 method, UH=SCS, Weighted -CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type IA 24 -hr WO Rainfall=0.83" 3,020 98 Paved parking, HSG B 3,020 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Summary for Pond 2P: (new Pond) Inflow Area = 0.069 ac,100.00% Impervious, Inflow Depth= 0.63" for WO event Inflow = 0.01 cfs @ 7.89 hrs, Volume= 0.004 of Outflow = 0.01 cfs @ 7.89 hrs, Volume= 0.004 af, Atten= 0%, Lag= 0.0 min Primary = 0.01 cfs @ 7.89 hrs, Volume= 0.004 of Routing by Dyn-Slor-Ind method, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 447.51'@ 7.89 hrs Flood Elev= 477.30' Device Routing Invert Outlet Devices #1 Primary 447.45' 8.0" Round Culvert L= 54.0' Ke= 0.500 Inlet /Outlet Invert= 447.45'/445.00' S=0.0454/' Cc= 0.900 n= 0.011, Flow Area= 0.35 sf Primary OutFlow Max=0.01 cfs @ 7.89 hrs HW=447.51' TW=444.28' (Dynamic Tailwater) 1=Culvert (Inlet Controls 0.01 cfs @ 0.81 fps) Summary for Pond 17P: (new Pond) Inflow Area = 0.244 ac,100.00% Impervious, Inflow Depth= 0.63" for WO event Inflow = 0.04 cfs @ 7.89 hrs, Volume= 0.013 of Outflow = 0.04 cfs @ 7.89 hrs, Volume= 0.013 af, Atten= 0%, Lag= 0.0 min Primary = 0.04 cfs @ 7.89 hrs, Volume= 0.013 of Routing by Dyn-Stor-Ind method, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 446.21'@ 7.89 hrs Flood Elev= 477.30' Device Routing Invert Outlet Devices #1 Primary 446.10' 8.0" Round Culvert L= 180.0' Ke= 0.500 Inlet /Outlet Invert= 446.10'/444.00' S=0.0117'/' Cc= 0.900 n= 0.011, Flow Area= 0.35 sf Design Modei Type IA 24 -hr WO Rainfall=0.83" Prepared by Microsoft Printed 4/24/2020 HydroCAD@ 10.00-24 s/n 10784 02018 HydroCAD Software Solutions LLC Paae 38 Primary OutFlow Max=0.04 cfs @ 7.89 hrs HW=446.21' TW=443.77' (Dynamic Tailwater) 1=Culvert (Inlet Controls 0.04 cfs @ 1.11 fps) Summary for Pond 18P: (new Pond) Inflow Area = 0.244 ac,100.00 % Impervious, Inflow Depth= 0.63" for WO event Inflow = 0.04 cfs @ 7.89 hrs, Volume= 0.013 of Outflow = 0.04 cfs @ 7.89 hrs, Volume= 0.013 af, Atten= 0%, Lag= 0.0 min Primary = 0.04 cfs @ 7.89 hrs, Volume= 0.013 of Routing by Dyn-Stor-Ind method, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 446.43'@ 7.89 hrs Device Routing Invert Outlet Devices #1 Primary 446.15' 8.0" Round Culvert L= 30.0' Ke= 0.500 Inlet /Outlet Invert= 446.15'/446.00' S=0.0050'/' Cc= 0.900 n= 0.011, Flow Area= 0.35 sf Primary OutFlow Max=0.04 cfs @ 7.89 hrs HW=446.43' TW=446.43' (Dynamic Tailwater) 1-11 =Culvert (Outlet Controls 0.04 cfs @ 0.42 fps) Summary for Pond 19P: (new Pond) Inflow Area = 0.244 ac,100.00% Impervious, Inflow Depth= 0.63" for WO event Inflow = 0.04 cfs @ 7.89 hrs, Volume= 0.013 of Outflow = 0.04 cfs @ 7.89 hrs, Volume= 0.013 af, Atten= 0%, Lag= 0.0 min Primary = 0.04 cfs @ 7.89 hrs, Volume= 0.013 of Routing by Dyn-Stor-Ind method, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 446.43'@ 7.89 hrs Device Routing Invert Outlet Devices #1 Primary 446.30' 8.0" Round Culvert L= 42.0' Ke= 0.500 Inlet /Outlet Invert= 446.30'/446.05' S= 0.0060'P Cc= 0.900 n= 0.011, Flow Area= 0.35 sf Primary OutFlow Max=0.04 cfs @ 7.89 hrs HW=446.43' TW=446.21' (Dynamic Tailwater) 1=Culvert (Outlet Controls 0.04 cfs @ 1.33 fps) Summary for Pond 3813: Aggregate Inflow Area = 0.860 ac,100.00% Impervious, Inflow Depth= 0.63" for WO event Inflow = 0.04 cfs @ 8.02 hrs, Volume= 0.045 of Outflow = 0.04 cfs @ 8.03 hrs, Volume= 0.045 af, Atten= 0%, Lag= 0.5 min Discarded = 0.04 cfs @ 8.03 hrs, Volume= 0.045 of Routing by Dyn-Slor-Ind method, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 442.00'@8.03 hrs Surf.Area= 3,000 sf Storage= 2 cf Plug -Flow detention time= 0.7 min calculated for 0.045 of (100% of inflow) Design Modei Type IA 24 -hr WO Rainfall=0.83" Prepared by Microsoft Printed 4/24/2020 HydroCAD®10.00-24 s/n 10784 © 2018 HydroCAD Software Solutions LLC Paae 39 Center -of -Mass det. time= 0.7 min ( 827.5 - 826.8) Volume Invert Avail.Storaae Storage Description #1 442.00' 1,980 cf Custom Stage Data (Prismatic) Listed below (Recalc) 6,000 cf Overall x 33.0% Voids Elevation Surf.Area Inc.Store Cum.Store (feet) (sq -ft) (cubic -feet) (cubic -feet) 442.00 3,000 0 0 444.00 3,000 6,000 6,000 Device Routing Invert Outlet Devices #1 Discarded 442.00' 3.500 in/hr Exfiltration over Surface area Phase -In= 0.01' Discarded OutFlow Max=0.04 cfs @ 8.03 hrs HW=442.00' (Free Discharge) L7=Exfiltration (Exfiltration Controls 0.04 cfs) Summary for Pond 41 P: Pond Inflow Area = 1.122 ac,100.00% Impervious, Inflow Depth = 0.63" for WO event Inflow = 0.18 cfs @ 7.89 hrs, Volume= 0.059 of Outflow = 0.13 cfs @ 8.10 hrs, Volume= 0.059 af, Atten= 31%, Lag= 12.6 min Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 of Secondary = 0.13 cfs @ 8.10 hrs, Volume= 0.059 of Routing by Dyn-Stor-Ind method, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 444.30'@8.10 hrs Surf.Area= 2,206 sf Storage= 100 cf Plug -Flow detention time= 3.9 min calculated for 0.059 of (1000/0 of inflow) Center -of -Mass det. time= 3.9 min ( 726.9 - 723.0 ) Volume Invert Avail.Storage Storage Description #1 444.25' 8,449 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq -ft) (cubic -feet) (cubic -feet) 444.25 2,140 0 0 446.50 5,370 8,449 8,449 Device Routing Invert Outlet Devices #1 Primary 448.50' 2.0' long x 0.50' rise Sharp -Crested Rectangular Weir 2 End Contraction(s) 1.0' Crest Height #2 Secondary 444.25' 2.500 in/hr Exfiltration over Surface area Phase -In= 0.01' Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=444.25' (Free Discharge) 1-11 =Sharp -Crested Rectangular Weir ( Controls 0.00 cfs) Secondary OutFlow Max=0.13 cfs @ 8.10 hrs HW=444.30' (Free Discharge) 2=Exfiltration (Exfiltration Controls 0.13 cfs) Design Model Type IA 24 -hr NO Rainfall=0.83" Prepared by Microsoft Printed 4/24/2020 HydroCAD@ 10.00-24 s/n 10784 02018 HydroCAD Software Solutions LLC Paae 40 Summary for Pond 42P: Pond Inflow Area = 0.115 ac,100.00% Impervious, Inflow Depth= 0.63" for WO event Inflow = 0.02 cfs @ 7.89 hrs, Volume= 0.006 of Outflow = 0.02 cfs @ 7.94 hrs, Volume= 0.006 af, Atten= I%, Lag= 2.9 min Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 of Secondary = 0.02 cfs @ 7.94 hrs, Volume= 0.006 of Routing by Dyn-Stor-Ind method, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 445.01'@7.94 hrs Surf.Area= 503 sf Storage= 3 cf Plug -Flow detention time= 2.9 min calculated for 0.006 of (100% of inflow) Center -of -Mass det. time= 2.9 min ( 725.9 - 723.0 ) Volume Invert Avail.Storage Storage Description #1 445.00' 1,940 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq -ft) (cubic -feet) (cubic -feet) 445.00 500 0 0 447.00 1,440 1,940 1,940 Device Routing Invert Outlet Devices #1 Primary 446.50' 2.0' long x 0.50' rise Sharp -Crested Rectangular Weir 2 End Contraction(s) 1.0' Crest Height #2 Secondary 445.00' 2.500 in/hr Pxdiltration over Surface area Phase -In= 0.01' Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=445.00' TW=442.00' (Dynamic Tailwater) 1-11 =Sharp -Crested Rectangular Weir ( Controls 0.00 cfs) Secondary OutFlow Max=0.02 cfs @ 7.94 hrs HW=445.01' TW=442.00' (Dynamic Tailwater) 2=Exfiltration (Exfiltration Controls 0.02 cfs) Summary for Pond 43P: Pond Inflow Area = 0.745 ac,100.00% Impervious, Inflow Depth= 0.63" for WO event Inflow = 0.12 cfs @ 7.89 hrs, Volume= 0.039 of Outflow = 0.03 cfs @ 10.17 hrs, Volume= 0.039 af, Atten= 77°/o, Lag= 136.6 min Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 of Secondary = 0.03 cfs @ 10.17 hrs, Volume= 0.039 of Routing by Dyn-Stor-Ind method, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 444.00'@ 10.17 hrs Surf.Area= 798 sf Storage= 334 cf Plug -Flow detention time= 119.4 min calculated for 0.039 of (1000/0 of inflow) Center -of -Mass det. time= 119.4 min ( 842.4 - 723.0) Volume Invert Avail.Storage Storage Description #1 443.50' 2,100 cf Custom Stage Data (Prismatic) Listed below (Recalc) Design Nbclei Type IA 24-hr WO Rainfall=0.83" Prepared by Microsoft Printed 4/24/2020 HWroCAD®10.00-24 s/n 10784 02018 HydroCAD Software Solutions LLC Pace 41 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 443.50 550 0 0 445.50 1,550 2,100 2,100 Device Routing Invert Outlet Devices #1 Primary 445.00' 2.0' long x 0.50' rise Sharp-Crested Rectangular Weir 2 End Contraction(s) 1.0' Crest Height #2 Secondary 443.50' 1.500 in/hr Exfiltration over Surface area Phase-In= 0.01' #3 Device 1 444.00' 8.0" Round Culvert L= 115.0' Ke= 0.500 Inlet/ Outlet Invert= 444.00'/443.00' S=0.0087'/' Cc= 0.900 n= 0.011, Flow Area= 0.35 sf Primary OutFlow Max-0.00 cfs @ 0.00 hrs HW=443.50' TW=442.00' (Dynamic Tailwater) 't'-1 =Sharp-Crested Rectangular Weir ( Controls 0.00 cfs) L3=Culvert ( Controls 0.00 cfs) Secondary OutFlow Max=0.03 cfs @ 10.17 hrs HW=444.00' TW=442.00' (Dynamic Tailwater) 2=Exfiltration (Exfiltration Controls 0.03 cfs) APPENDIX C Operations and Maintenance Plan Notice of Operations and Maintenance Agreement Private Stormwater Management and Treatment System The undersigned owner(s), is hereby given notice that stormwater runoff from the "Propery" described below requires stormwater management facilities to be located, designed, and constructed in compliance with the City of Springfield's Engineering Design and Procedures Manual. Said facilities shall be operated and maintained in accordance with the Operations and Maintenance Agreement (O&M Agreement) on file with the City of Springfield, Development and Public Works Department. (Property Owner/Developer) acknowledges and agrees to maintain private stormwater treatment facilities listed in this document. The maintenance of the storrnwater facilities listed in this document is required as part of the Development Agreement with the City of Springfield. This facility will be operated and maintained in accordance with the requirements stated in this document and in the latest edition of the City of Springfield Engineering Design Standards and Procedures Manual, Chapter 3. The City reserves the right to enter and inspect any stormwater facility located on the "Property' to ensure the facilities are operating as designed. Failure of the responsible party to inspect and maintain the facilities can result in an adverse impact to the public storrnwater system and the quality of receiving waters. The requirement to operate and maintain the stormwater treatment facilities in accordance with the approved site development agreement and the site O&M Agreement is binding on all current and future owners of the property. The Agreement and its O&M Plan maybe modified under written consent of new owners with written approval by and re -filing with the City. The O&M Agreement and O&M Plan for facilities constructed pursuant to this notice are available at the Development and Public Works Department, 225 Fifth St, Springfield Oregon, or call (541)-736-3753, between the hours of S a.m. and 5 IT m., Monday through Friday. The Subject premises, is legally described as follows: (Tax lot natter camat be usedio describe tic property. Legal descriptions may be obtairedfronu the county assessor's office). SEE EXHIBIT "A" ATTACHED HERETO AND INCORPORATED HEREIN BY REFERENCE By signing below, the signer accepts and agrees to the terms and conditions contained in the Operations and Maintenance Plan and in any documents attached. This instrument is intended to be binding upon the parties hereto, their heirs, successors, and assigns. In Witness whereof, the undersigned has executed this instrument on this day of 20 Owner(s): Signature Print Name STATE OF OREGON, County of Lane, This instrument as acknowledged before me on , by , owner(s) of the above described premises. This instrument as acknowledged before me on by RS of Notary Public for Oregon RETURN TO: CITYOF SPRINGFIELD DEVELOPMENT &PUBLIC WORKS DEPT. 225 FIFTH ST. SPRINGFIELD, OREGON 97477 owner(s) of the above described My Commission Expires RESERVE THIS SPACE FOR RECORDING STICKER "Avoid $20 nonstanda (font too small)... Print this form on Legal size paper." Appendix 3A-1 Rmormirr Page 1 of 1 EDSP Adopted December 03, 2012 Operations and Maintenance Agreement Private Stormwater Management and Treatment System Land Development Application Number: Owner's Name: Phone No.: Mailing Address: City State Zip Site Address: City State Zip Site Map and Tax lot No.: Tax Map: Tax Lot. (Ofi oti rnvrtian iftluf¢ility crosses nnre thmiore lot) Type ofFacility(ies) Raingardens Requirements 1) Stormwater Management Site Plan, (min. S 1/2" x 11" attached to this form) showing the location of the facility(ies) in relation to building structures or other permanent monuments on the site, sources of nmoff entering the facility(ies), and where stormwater will be discharged to after leaving the facility(ies). Landscape and vegetation should be clear on the Plan submitted or submit a separate Landscape Plan document showing vegetation type, location, and quantity (landscape plan). These can be the same Plans submitted for development review. The storrawater management facility(ies) shown on the Site Plan are arequired condition of development approval for the identified property. The owner of the identified property is required to operate and maintain the facility(ies) in accordance with the Facility Specific Operation and Maintenance Plan(s) (O&M Plan(s)) attached to this form and on file with the City. The O&M Plan for the fa.cility(ies) will be available at the Development and Public Works Department, 225 56 Street, Springfield, Oregon between the hours of S a.m. and 5 p.m., Monday through Friday. 2) Financially responsible party (circle one): Property Owner Homeowner Association Other (describe) 3) Party(ies) responsible for maintenance (only if other than owner). Daytime phone no.(_)_ Emergency/after-hours contact phone no ( ) Maintenance Contact Party(ies) Name & Business Address: 4) Maintenance practices and schedule for the stormwater facility(ies) are included in the Facility Specific O&M Plan(s) attached to this form and filed with the Development and Public Works Department, City of Springfield. The operation and maintenance practices are based on the version of the City of Eugene's Stormwater Management Manual in effect at the date of development application, as modified by any plans attached to this document at the time of signing. Application Date: By signing below, Filer accepts and agrees to the terms and conditions contained in the Operations and Maintenance Plan(s) and in any document executed by Filer and recorded with it. Filer Signature: Print Name: Appendix 3A-2 aerorrz&ra Page 1 of 1 EDSP Adopted December 03, 2012 STORMWATER MANAGEMENT FACILITY INSPECTION AND MAINTENANCE LOG Property Address: Inspection Date: Ins ection Time: Inspected By: Approximate Date/Time of Last Rainfall: Type of Stormwater Management Facility: Location of Facility on Site (In relation to buildings or other permanent structures): Water levels and observations (Oil sheen, smell, turbidity, etc.): Sediment accumulation and record of sediment removal: Condition of vegetation (Height, survival rates, invasive species present, etc.) and record of replacement and management (mowing, weeding, etc.): Condition of physical properties such as inlets, outlets, piping, fences, irrigation facilities, and side slopes. Record damaged items and replacement activities: Presence of insects or vectors. Record control activities: Identify safety hazards present. Record resolution activities: Appendix 3A-3 Page 1 of 1 EDSP Adopted December 03, 2012 Soakage Trenches Operations and Maintenance Plan Soakage Trenches consist of drain rock and sand, and receive stormwater from roof downspouts and/or area drains. There are various components within the system — piping, silt basin and the trench itself. The Conveyance Piping consists of an inlet pipe (downspout or area drain), an outlet pipe located between the silt basin and the soakage trench, and a perforated pipe, located on top of the aggregate bed of the soakage trench. The Silt Basin is a structure receiving runoff from aninlet pipe and conveying it to the soakage trench. The silt basin serves as the pre-treatment system for the soakage trench, removing sediments and other debris that can impact its proper functioning. All facility components, vegetation, and source controls shall be inspected for proper operations and structural stability. These inspections shall occur, at a minimum, quarterly for the first two years from the date of installation, then two times per year afterwards, or within 48 hours after each major storm. The facility owner must keep a log, recording all inspection dates, observations, and maintenance activities. The following items shall be inspected and maintained as stated: Soakage trench infiltration: If water is noticed on top of the trench within 48 hours of a maj or stomr, the soakage trench may be clogged. • Check for debris/sediment accumulation, rake and remove and evaluate upland causes (erosion, surface or roof debris, etc. • Assess the condition of the aggregate and the filter fabric in the trench. If there is sediment in the aggregate, excavate and replace. • If there is a tear in the filter fabric, repair or replace. • The soakage trench area shall be protected from compaction during construction. Conveyance Piping: If water ponds over the trench for more than 48 hours after a major storm and no other cause if identified, it may be necessary to remove the filter fabric to determine if the perforated pipe is clogged with sediment or debris. • Any debris or algae growth located on top of the soakage trench should be removed and disposed of properly. • If the piping has settled more than 1 -inch, add fill material. If there are cracks or releases, replace or repair the pipe. If there are signs of erosion around the pipe, this may be an indication of water seeping due to a crack or break. SiltBasin If water remains in the soakage trench for 36-48 hours after storm, check for sediment accumulation in the silt basin • If less than 50% capacity remains in the basin or 6" of sediment has accumulated, remove and dispose the sediment. Spill Prevention: Virtually all sites, including residential and commercial, present dangers from spills. All homes contain a wide variety of toxic materials including gasoline for lawn mowers, antifreeze for cars, nail polish remover, pesticides, and cleaning aids that can adversely affect groundwater if spilled. It is important to exercise caution when handling substances that can contaminate stornawater. • Activities that pose the chance of hazardous material spills shall not take place near soakage trenches. A ShutOffValve or FlowBlockingMechanism may have been required with the construction of the soakage trench to temporarily prevent stormwater from flowing into it, in the event of an accidental material spill. This may also involve mats kept on-site that can be used to cover inlet drains in parking lots. The shut-off valve shall remain in good working order, or if mats or other flow -blocking mechanisms are used, they shall be kept in stock on-site. Training and/or written guidance information for operating and maintaining soakage trenches shall be provided to all property owners and tenants. A copy of the O&M Plan shall be provided to all property owners and tenants. Access to the soakage trench is required for efficient maintenance. Egress and ingress routes will be maintained to design standards at inspections. Appendix 3A-4 Page 19 of 31 EDSP Adopted December 03, 2012 Insects and Rodents shall not be harbored in the soakage trench. Pest control measures shall betaken when insects/rodents are found to be present. • If a complaint is received or an inspection reveals that a stormwater facility is significantly infested with mosquitoes or other vectors, the property owner/owners or their designee may be required to eliminate the infestation at the City inspector's discretion. Control of the infestation shall be attempted by using first non -chemical methods and secondly, only those chemical methods specifically approved by the City's inspector. Acceptable methods include but are not limited to the following: i. Installation of predacious bird or bat nesting boxes. ii. Alterations of pond water levels approximately every four days in order to disrupt mosquito larval development cycles. iii. Stocking ponds and other permanent water facilities with fish or other predatory species. iv. If non -chemical methods have proved unsuccessful, contact the City inspector prior to use of chemical methods such as the mosquito larvicides Bacillus fl urengensis var. israchemis or other approved larva ides. These materials may only be used with City inspector approval if evidence can be provided that these materials will not migrate off-site or enter the public stormwater system. Chemical larvicides shall be applied by a licensed individual or contractor. • Holes in the ground located in and around the soakage trench shall be filled. Appendix 3AA Page 20 of 31 EDSP Adopted December 03, 2012 Wet, Extended Wet Detention and Dry Detention Ponds Operations and Maintenance Plan Wet Ponds are constructed ponds with a permanent pool of water. Pollutants are removed from stormwater through gravitational settling and biologic processes. Extended Wet Detention Ponds are constructed ponds with a permanent pool of water and open storage space above for short-term detention of large storm events. Pollutants are removed from stormwater through gravitational settling and biologic processes. Dry Detention Ponds are constructed ponds with temporary storage for the detention of large storm events. The stormwater is stored and released slowly over a matter of hours. All facibty components, vegetation, and source controls shall be inspected for proper operations and structural stability. These inspections shall occur, at a minimum, quarterly for the first 2 years from the date of installation, and 2 times per year thereafter, and within 48 hours after each maj or storm event. The facility owner must keep a log, recording all inspection dates, observations, and maintenance activities. The following items shall be inspected and maintained as stated: Pond Inlet shall assure umeshicted stormwater flow to the wet pond. • Inlet pipe shall be cleared when conveyance capacity is plugged. Sources of sediment and debris shall be identified and corrected. • Determine if pipe is in good condition: o If more than 1 inch of settlement, add fill material and compact soils. o If alignment is faulty, correct alignment. o If cracks or openings exist indicated by evidence of erosion at leaks, repair or replace pipe as needed. Forebay traps coarse sediments, reduces incoming velocity, and distributes runoff evenly over the wet pond. A minimum 1 -foot freeboard shall be maintained. • Sediment buildup exceeding 50% of the facility capacity shall be removed every 2-5 years or sooner if performance is being affected. Embankment, Dikes, Berms and Side Slopes retain water in the wet pond. • Slopes shall be stabilized using appropriate erosion control measures when native soil is exposed or erosion channels are forming. • Structural deficiencies shall be corrected upon discovery: o If cracks exist, repair or replace structure. o If erosion channels deeper than 2 inches exist, stabilize surface. Sources of erosion damage shall be identified and controlled. Control Devices (e.g., weirs, baffles, etc.) shall direct and reduce flow velocity. Structural deficiencies shall be corrected upon discovery: • If cracks exist, repair or replace structure. Overflow Structure conveys flow exceeding reservoir capacity to an approved stormwater receiving system. • Overflow structure shall be cleared when 50% of the conveyance capacity is plugged. Sources of sediment and debris shall be identified and corrected. • Sources of erosion damage shall be identified and controlled when native soil is exposed at the top of overflow structure or erosion channels are forming. • Rocks or other samorring shall be replaced when only one layer of rock exists above native soil. Sediment and Debris Management shall prevent loss of wet pond volume caused by sedimentation. • Wet ponds shall be dredged when 1 foot of sediment accumulates in the pond. • Gauges located at the opposite ends of the wet pond shall be maintained to monitor sedimentation. Gauges shall be checked 2 times per year. • Sources of restricted sediment or debris, such as discarded lawn clippings, shall be identified and prevented. • Debris in quantities sufficient to inhibit operation shall be removed routinely, e.g. no less than quarterly, or upon discovery. • Litter shall be removed upon discovery. Section I - Chapter 3 Page 32 of 41 EDSP Adopted December 03, 2012 Appendix 3A Submittal Packet WO Information Vegetation shall be healthy and dense enough to provide filtering while protecting underlying soils from erosion and minimizing solar exposure of open water areas. • Mulch shall be replenished at least annually. • Vegetation, large shrubs or trees that limit access or interfere with wet pond operation shall be pruned or removed. • Grass (where applicable) shall be mowed to 4 inch -9 inch high and grass clippings shall be removed if build up is damaging vegetation. • Fallen leaves and debris from deciduous plant foliage shall be raked and removed if build up is damaging vegetation. • Nuisance or prohibited vegetation (such as blackberries or English Ivy) shall be removed when discovered. Invasive vegetation contributing up to 25% of vegetation of all species shall be removed and replaced. • Dead vegetation shall be removed to maintain less than 10% of area coverage or when wet pond function is impaired. Vegetation shall be replaced within 3 months, or immediately if required to maintain cover density and control erosion where soils are exposed. If removing a dead or hazard tree a permit maybe required, contact the City's Public Works Department for details on tree removal. • Vegetation producing foul odors shall be eliminated. Spill Prevention measures shall be exercised when handling substances that can contaminate stormwater Releases of pollutants shall be corrected as soon as identified. Training and/or written guidance information for operating and maintaining ponds shall be provided to all property owners and tenants. A copy of the O&M Plan shall be provided to all property owners and tenants. Access to the wet pond shall be safe and efficient. Egress and ingress routes shall be maintained to design standards. Roadways shall be maintained to accommodate size and weight of vehicles, if applicable. • Obstacles preventing maintenance personnel and/or equipment access to the wet pond shall be removed. • Gravel or ground cover shall be added if erosion occurs, e.g., due to vehicular or pedestrian traffic. Insects and Rodents shall not be harbored in the pond. Pest control measures shall be taken when insectstroderds are found to be present. • If a complaint is received or an inspection reveals that a stormwater facility is significantly infested with mosquitoes or other vectors, the property owner/owners or their designee may be required to eliminate the infestation at the City inspector's discretion. Control of the infestation shall be attempted by using first non -chemical methods and secondly, only those chemical methods specifically approved by the City's inspector. Acceptable methods include but are not limited to the following: i. Installation of predacious bird or bat nesting boxes. ii. Alterations of pond water levels approximately every four days in order to disrupt mosquito larval development cycles. iii. Stocking ponds and other permanent water facilities with fish or other predatory species. iv. If non -chemical methods have proved unsuccessful, contact the City inspector prior to use of chemical methods such as the mosquito larvicides Bacillus thurengensis var. isracliensis or other approved larvicides. These materials may only be used with City inspector approval if evidence can be provided that these materials will not migrate off-site or enter the public stormwater system. Chemical larvicides shall be applied by a licensed individual or contractor. • Holes in the ground located in and around the pond shall be filled. If used at this site, the following will be applicable: Signage shall clearly convey information. • Broken or defaced signs shall be replaced or repaired. Fences shall be maintained to preserve their functionality and appearance. • Collapsed fences shall be restored to an upright position. • Jagged edges and damaged fences and shall be repaired or replaced. Section I - Chapter 3 Page 33 of 41 EDSP Adopted December 03, 2012 Appendix 3A Submittal Packet WO Information /_\»�►191KI91 Infiltration Data *anch INEERIMb a d'L�Ii IR&MIe 11 FERTIMI Eec-aaz�a OmE��® o ao®m0 ��I�YrTJI�1��11�i1R1l1RTlST!�!1 0ma�0�0 m o0®�0 W ve®�0