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HomeMy WebLinkAbout2022-08-16 Stevens Engineers - Stormwater Management Plan Storm Water Management Plan St. Croix Car Wash Oak Park Heights, Minnesota August 16, 2022 Prepared by: 642 Brakke Drive Suite 202, Hudson, WI 54016 Phone (715) 386-5819 Storm Water Narrative St. Croix Car Wash August 16, 2022 Page 2 of 6 Storm Water Calculations for St. Croix Car Wash Oak Park Heights, Minnesota August 16, 2022 Table of Contents SUMMARY Site Overview SITE ANALYSIS & SCREENING Soils Review Topographic Analysis Endangered Resources Nearby Waterbodies and Wetlands STORMWATER MANAGEMENT TECHNICAL BASIS Required Standards Rate Control Summary Water Quality Summary Maintenance Agreement Appendix Appendix A – Location Map Appendix B – Endangered Resources Review Appendix C – Waterbodies and Wetlands Appendix D – MIDS Flowchart Appendix E – Pre and Post Development Drainage Map Appendix F – Site Modeling (Hydrocad) Appendix G – P8 Modeling Output Appendix H – Phosphorus Calculation Prepared by: 642 Brakke Drive Suite 202, Hudson, WI 54016 Phone (715) 386-5819 Storm Water Narrative St. Croix Car Wash August 16, 2022 Page 3 of 6 SUMMARY Site Overview The purpose of this report is to provide an analysis of the stormwater management plan for the St. Croix Car Wash redevelopment site in Oak Park Heights, Minnesota. The property consists of a paved parking lot used for overflow parking from the adjacent Tire Pros Building. Proposed improvements include connections to adjacent streets, construction of a car wash and storage building, and improvements to the parking areas through the installation of curb and gutter, bituminous pavement and storm water management. SITE ANALYSIS & SCREENING Soils Review USDA soils map shows Urban land-Chetek complex and does not provide a HSG rating for the soils. For this analysis, we have assumed no infiltration below the underdrain. Soil borings were not completed since the City of Oak Park Heights prohibits infiltration, and our design is based on engineered filtration media with underdrains. Topographic Analysis The existing property survey along with Washington County Lidar was utilized to determine overall drainage areas. The property generally drains from the south to the northeast with a small strip of land along the west property line that drains west. The proposed improvements retain the original drainage patterns but capture the runoff from the proposed impervious into 2 filtration basins. The west portion will continue to drain to the west. Endangered Resources The Washington County Biological Survey Native Plan Community and Rare Species Map was utilized as a preliminary assessment and concluded that there are no endangered resources in this area. Storm Water Narrative St. Croix Car Wash August 16, 2022 Page 4 of 6 Nearby Waterbodies and Wetlands MnDNR MWI Wetland Finder was utilized to determine wetlands in the areas. There are no wetland indicators near this property. MPCA Construction Stormwater Special Waters search was utilized to check for outstanding or impaired waters within 1 mile of the site. The only water body within 1 mile of the site is Lily Lake, which has a Mercury impairment and no impact to stormwater runoff. STORMWATER MANAGEMENT TECHNICAL BASIS Required Standards · MSCWMO Requirements for sites disturbing greater than 10,000 SF of land: o Rate control of 2, 10, and 100-year o Volume Control – capture/retain 1.1” of runoff from new and/or fully reconstructed surfaces  Alternative compliance sequencing applies since Oak Park Heights requires filtration rain gardens*** · Oak Park Heights Requirements – provide a filtration rain garden, NO infiltration allowed Rate Control Summary The pre-development and post-development hydrology were modeled in HydroCAD software using MSE 3 Rainfall Distribution, 24-hour duration storm and MSCWMO recommended rainfall depths. A summary of the outflows is below and the full HydroCAD output is attached to this report as Appendix F. Outflow – Storm Event and Location Existing (cfs) Proposed (cfs) 2-Year Storm Event Offsite to West 0.10 0.10 Offsite to North 1.79 1.47 10-Year Storm Event Offsite to West 0.22 0.22 Offsite to North 3.11 2.81 100-Year Storm Event Offsite to West 0.51 0.52 Offsite to North 6.07 5.72 Storm Water Narrative St. Croix Car Wash August 16, 2022 Page 5 of 6 Water Quality Summary Water quality is calculated for the new and reconstructed impervious surfaces. Total new and reconstructed impervious areas = 17,242 SF. At 1.1 inches over this entire area, the site water quality volume is 2,581 CF. The water quality volume is the volume required to infiltrate onsite. Since the City of Oak Park Heights disallows infiltration, the site is subject to alternative compliance sequencing per the MIDS Calculator. Appendix D shows the marked- up MIDS flowchart. Since infiltration is completely disallowed, the site is subject to FTO #2 – volume reduction to the maximum extent practicable AND Remove 60% of annual TP load. Total annual phosphorus removal is calculated using the Mn Stormwater Manual guidelines for particulate phosphorus and dissolved phosphorus. P8 is not accurate in calculating phosphorus removal with a filtration basin, so manual calculation is required. P8 was used to determine volume of runoff treated for a year vs volume of runoff leaving the site untreated. Total phosphorus removal was calculated at 59%. While the requirement is 60%, we have modified the site and re-graded to catch the maximum volume of runoff for the site as possible and are requesting lenience for the 1% calculated shortfall of this site stormwater design. With infiltration disallowed by the City, few options considered on this small site were feasible while still allowing a functional site. A wet pond would help with phosphorus removal, but there physically isn’t enough space on the site to provide adequate pretreatment and wet pond volume. The runoff to the west is on a slope and is impossible to capture before traveling to the adjacent parcel. Rain gardens were considered, but do not adequately treat the dissolved portion of the phosphorus loading. Therefore, iron enhanced media will be used to enhance phosphorus removal and meet FTO #2 requirements. Offsite mitigation was not considered, as it should be a last resort when all other options fail. Both filtration basins will be iron-enhanced, with 5-8% iron filings included per the MPCA stormwater manual guidelines. Bottom of the basin will be bare to allow the iron filings to operate properly, with plantings on the sides of the basin for aesthetics. Storm Water Narrative St. Croix Car Wash August 16, 2022 Page 6 of 6 Monitoring and Inspection Monitoring and inspection of the site will occur on a quarterly basis on the first 5 years to observe that the facilities continue to function as they are intended to. After the first 5 years, monitoring can occur annually. This monitoring will consist of checking for erosion and ensuring no garbage or debris are located within the filtration basin and raking the bottom media as well as inspecting and cleaning Rain Guardian structures. Appendix A Location Map APPENDIX A – LOCATION MAP Appendix B Endangered Resources Appendix C Waterbodies and Wetlands PFO1A PFO1A PFO1A PEM1A Date Printed: 08/16/2022 This map is for general reference only. Neither the state of Minnesota nor the Minnesota Department of Natural Resources make any representations or warranties with respect to the use of or reliance on the data. There are no guarantees as to the accuracy, currency, completeness, suitability or reliability of this data for any purpose. 0 0.1 0.20.05 mi National Wetland Inventory Project Location MPCA's Construction Stormwater Special Waters Search Washington County, MN, Esri Canada, Esri, HERE, Garmin, GeoTechnologies, Inc., USGS, METI/NASA, EPA, USDA Waterbody Units - Lakes (1) Waterbody Units - Streams (1) Impaired Lakes without additional construction requirements Impaired Lakes with additional construction requirements Scenic and Recreational River Segments 8/16/2022, 9:34:22 AM 0 0.2 0.40.1 mi 0 0.35 0.70.17 km 1:18,056 Minnesota Pollution Control Agency Washington County, MN, Esri Canada, Esri, HERE, Garmin, GeoTechnologies, Inc., USGS, METI/NASA, EPA, USDA | Minnesota Pollution Control Agency | 0.40 mi0.84 m i Appendix D MIDS Flowchart Conduct Site Review: · Aerial Photos and Topographic Maps · County Soil Surveys and other Soil Information as Available · County Geologic Atlas · Local Groundwater Levels · DWSMA and Wellhead Protection Maps · FEMA and Local Floodplain Maps · Soil Borings and Site Survey · MPCA Listing of Potentially Contaminated Sites · Phase 1 and 2 Environmental Site Assessments · TMDLs and Local Water Quality Standards · Wetland Delineations, MNRAM Assessments, and Wetland Classifications · Proposed Conditions, Conceptual/Preliminary Site Design · Local zoning and land use requirements/ordinances, including stormwater rate control requirements · Communication with Local Landowners, LGU, or Others Knowledgeable about the Site · Site Inspection Is shallow groundwater or shallow bedrock present on site? Are there very low infiltrating soils (<0.2 inches per hour)? Is BMP relocation onsite to avoid shallow groundwater and bedrock feasible? Conduct detailed site investigation (i.e., borings, excavations, consultation with a professional geologist). Is there >3 feet of soil depth (> 10 feet is preferred) from bottom of BMP to bedrock and groundwater? Can BMP be raised? Can BMP be sized to drain dry within 48 hours (24 hours in locations that are tributary to trout streams)? Define Performance Goal New and redevelopment projects: Retain on site a volume of 1.1" from impervious surfaces Linear projects: Retain on site the larger of 1.1" from all new, or .55" from all new and fully reconstructed (D) impervious surfaces. Is the site located in a DWSMA, wellhead protection area, or within 200 feet of a drinking well? Yes Are there existing or proposed structures or infrastructure (e.g., rate control BMPs, utilities, buildings, roadway, easements) that make the Performance Goal not feasible? (G) No Is BMP relocation feasable?Yes No Is FTO Alternative No. 1 feasible?No No No Raise BMP enough to ensure 3 feet (preferably 10 feet) of soil between bottom of BMP and top of bedrock and groundwater. Yes Is there presence of contaminated soils and/ or groundwater, or hotspot runoff? (H) No Can hotspot or contamination be isolated or remediated to mitigate risk of increased contamination? Yes No Yes Is BMP relocation onsite to a higher-infiltrating location feasible? Yes No Provide soil boring or infiltration test results documenting low-infiltrating soils. Is FTO Alternative No. 1 (lower volume control standard) feasible, allowing the BMP to drain within 48 hours (24 hours in locations that are tributary to trout streams)? No No Are there very high infiltrating soils (>8 inches per hour)? (E) No Yes Yes Yes Is BMP relocation onsite to a lower-infiltrating location feasible? Can subgrade be modified to slow the rate of infiltration to less than 8 inches per hour? Yes No No Yes Yes MIDS DESIGN SEQUENCE FLOW CHART version 6.18.13 · Select FTO Alternative No. 1 · Provide soil boring or infiltration test results documenting high-infiltrating soils. Is the project linear? Are there zoning and land use requirements (density, parking, setbacks, etc.) that make the Performance Goal not feasible? (G) No Is BMP relocation feasible? Is FTO Alternative No. 1 feasible? Select FTO #3. Provide site survey, maps, regulations, and/or cost estimates documenting that meeting the original performance goal or FTO alternatives is not feasible in addition to other documentation as required by LGU. NoYesNo Is FTO Alternative No. 2 feasible? Can a local unit of government provide a higher level of engineering review to ensure a functioning system that prevents adverse impacts to groundwater? Is FTO Alternative No. 2 feasible? Are active karst areas within 1000 feet up- gradiant or 100 feet downgradiant of the BMP location? No Yes No Are there adverse surface water hydrologic impacts from infiltration practices (e.g., impacting perched wetland)? Can the BMP be relocated onsite to avoid adverse hydrologic impacts? Yes Is BMP relocation onsite to a location without karst feasible? Yes No Would BMPs accommodating FTO Alternative #1 avoid adverse hydrologic impacts?Yes No MIDS performance goal does not apply Does the project create one acre or more of new and/or fully reconstructed (D) impervious surfaces? No Is FTO Alternative No. 2 feasible? Yes Yes No No No Complete Design Using Performance Goal (As modified by FTO Alternatives, if applicable) No Yes Yes No No · Select FTO Alternative No. 2 · No infiltration practices allowed · Explore non-infiltration volume reduction practices · Provide soil boring or infiltration test results documenting low infiltration rates. · Select FTO Alternative No. 2 · No infiltration practices allowed · Explore non-infiltration volume reduction practices · Provide soil boring or infiltration test results documenting high-infiltrating soils. · Select FTO Alternative No. 2 · Maximize infiltration BMPs to treat up to the 0.55 inch goal, if possible. · Explore non-infiltration volume reduction practices · Provide report documenting potential hydrologic impacts from infiltration on the site, prepared by registered engineer, hydrologist, or wetlands specialist. · Select FTO Alternative No. 1 · Maximize infiltration BMPs to treat more than 0.55 inch goal, if possible. · Provide report documenting potential hydrologic impacts from infiltration on the site, prepared by registered engineer, hydrologist, or wetlands specialist. · Select Flexible Treatment Option (FTO) Alternative No. 2 · No infiltration practices allowed · Explore non-infiltration volume reduction practices · Provide Phase I or II ESAs, or other documentation of potential contamination or hotspot runoff · Provide documentation of extent of contamination and remediation alternatives considered · Select Flexible Treatment Option (FTO) Alternative No. 2 · No infiltration practices allowed · Explore non-infiltration volume reduction practices · Provide soil borings or report from a professional geologist or geotechnical engineer. · Select Flexible Treatment Option (FTO) Alternative No. 2 · No infiltration practices allowed · Explore non-infiltration volume reduction practices · Provide soil borings or report from a professional geologist or geotechnical engineer. · Select Flexible Treatment Option (FTO) Alternative No. 2 · Provide regulations, and/or cost estimates documenting infeasibility of meeting the original Performance Goal · Select Flexible Treatment Option (FTO) Alternative No. 1 · Provide regulations, and/or cost estimates documenting infeasibility of meeting the original Performance Goal · Select Flexible Treatment Option (FTO) Alternative No. 2 · No infiltration practices allowed · Explore non-infiltration volume reduction practices · Provide DWSMA or well location map · Select Flexible Treatment Option (FTO) Alternative No. 1 · Provide regulations, and/or cost estimates documenting infeasibility of meeting the original Performance Goal · Select Flexible Treatment Option (FTO) Alternative No. 2 · Provide regulations, and/or cost estimates documenting infeasibility of meeting the original Performance Goal. · Select Flexible Treatment Option (FTO) Alternative No. 2 · Provide documentation of offsite run on to project area · Provide documentation of lack of right-of-way. Yes No Are there restraints due to lack of available ROW, off site drainage and/or rate control requirements? (F) Yes Yes No NoNo Yes Select FTO #3. Provide site survey, maps, regulations, and/or cost estimates documenting that meeting the original performance goal or FTO alternatives is not feasible in addition to other documentation as required by LGU.No Yes Yes Yes No Yes MIDS Project Flexible Treatment Options (FTO) The Flexible Treatment Options (FTO) alternatives presented here should be employed when the Performance Goal is not feasible and/or allowed. The designer should document the reasons why the Performance Goal and rejected FTO Alternatives are not feasible and/ or allowed. FTO 1 Applicant attempts to comply with the following conditions: 1.a. Achieve at least 0.55” volume reduction goal, and 1.b.Remove 75% of the annual TP load, and 1.c. Options considered and presented shall examine the merits of relocating project elements to address, varying soil conditions and other constraints across the site FTO #2 Applicant attempts to comply with the following conditions: 2.a. Achieve volume reduction to the maximum extent practicable (as determined by the Local Authority), and 2.b.Remove 60% of the annual TP load, and 2.c. Options considered and presented shall examine the merits of relocating project elements to address, varying soil conditions and other constraints across the site. FTO #3 Off-site mitigation (including banking or cash or treatment on another project, as determined by the local authority) equivalent to the volume reduction performance goal can be used in areas selected in the following order of preference: 1. Locations that yield benefits to the same receiving water that receives runoff from the original construction activity 2) Locations within the same Department of Natural Resource (DNR) catchment area as the original construction activity 3) Locations in the next adjacent DNR catchment area up-stream 4) Locations anywhere within the local authorities jurisdiction Notes: A. Volume reduction techniques considered shall include infiltration, rainwater harvesting & reuse, bioretention, permeable pavement, tree boxes, grass swales and/or additional techniques included in the MIDS calculator or the Minnesota Stormwater Manual. B. Applicant shall document the flexible treatment options decision sequence, following the order of alternatives presented here. C. For Alternative #2, the applicant is encouraged to use BMPs that reduce volume. Secondary preference is to employ filtration techniques, followed by rate control BMPs. D. Fully reconstructed impervious surfaces: Areas where impervious surfaces have been removed down to the underlying soils. Activities such as structure renovation, mill and overlay projects and other pavement rehabilitation projects that do not alter the underlying soil material beneath the structure, pavement or activity are not considered full reconstruction. In addition, other maintenance activities such as catch basin and pipe repair/ replacement, lighting, and pedestrian ramp improvements shall not be considered fully reconstructed impervious surfaces. Reusing an existing building foundation and re-roofing of an existing building are not considered fully reconstructed. E. Soils that infiltrate too quickly may not provide sufficient pollutant removal before the infiltrated runoff enters groundwater. F. A reasonable attempt must be made to obtain right-of-way during the project planning process G. Other, this is not an exhaustive list Is FTO Alternative No. 2 feasible? Select FTO #3. Provide site survey, maps, regulations, and/or cost estimates documenting that meeting the original performance goal or FTO alternatives is not feasible in addition to other documentation as required by LGU. NO YES Is FTO Alternative No. 2 feasible? Select FTO #3. Provide site survey, maps, regulations, and/or cost estimates documenting that meeting the original performance goal or FTO alternatives is not feasible in addition to other documentation as required by LGU. H. Hotspots includes any portion of a facility where infiltration is prohibited under an NPDES/SDS industrial stormwater permit issued by the MPCA Can a local unit of government provide a higher level of engineering review to ensure a functioning system that prevents adverse impacts to groundwater? YES YESYES YES NO We are less than 1 acre, but we respond with YES per Matt from MSCWMO Appendix E Pre and Post Development Drainage Map APPENDIX C - PRE-DEVELOPMENT DRAINAGE MAP APPENDIX C - POST-DEVELOPMENT DRAINAGE MAP Appendix F Site Modeling (Hydrocad) Exisitng conditions 2S Area 1 3S Area 2 4S Area 3 1P Offsite to Gas Station 5P Offsite to Frontage 6P Offsite to West 9P Offsite to North Routing Diagram for Tire Pros Prepared by Stevens Engineers, Printed 8/16/2022 HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Subcat Reach Pond Link Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 2HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Area Listing (selected nodes) Area (acres) CN Description (subcatchment-numbers) 0.363 74 >75% Grass cover, Good, HSG C (2S, 3S, 4S) 0.075 96 Gravel surface, HSG C (2S) 0.355 98 Paved parking, HSG C (3S, 4S) 0.793 87 TOTAL AREA Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 3HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Soil Listing (selected nodes) Area (acres) Soil Group Subcatchment Numbers 0.000 HSG A 0.000 HSG B 0.793 HSG C 2S, 3S, 4S 0.000 HSG D 0.000 Other 0.793 TOTAL AREA Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 4HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Ground Covers (selected nodes) HSG-A (acres) HSG-B (acres) HSG-C (acres) HSG-D (acres) Other (acres) Total (acres) Ground Cover Subcatchment Numbers 0.000 0.000 0.363 0.000 0.000 0.363 >75% Grass cover, Good 2S, 3S, 4S 0.000 0.000 0.075 0.000 0.000 0.075 Gravel surface 2S 0.000 0.000 0.355 0.000 0.000 0.355 Paved parking 3S, 4S 0.000 0.000 0.793 0.000 0.000 0.793 TOTAL AREA MSE 24-hr 3 2-year Rainfall=2.80"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 5HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Time span=5.00-20.00 hrs, dt=0.05 hrs, 301 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=10,849 sf 0.00% Impervious Runoff Depth>1.10"Subcatchment 2S: Area 1 Tc=10.0 min CN=81 Runoff=0.44 cfs 0.023 af Runoff Area=20,973 sf 72.65% Impervious Runoff Depth>1.81"Subcatchment 3S: Area 2 Tc=10.0 min CN=91 Runoff=1.35 cfs 0.073 af Runoff Area=2,724 sf 8.99% Impervious Runoff Depth>0.83"Subcatchment 4S: Area 3 Tc=5.0 min CN=76 Runoff=0.10 cfs 0.004 af Inflow=0.44 cfs 0.023 afPond 1P: Offsite to Gas Station Primary=0.44 cfs 0.023 af Inflow=1.35 cfs 0.073 afPond 5P: Offsite to Frontage Primary=1.35 cfs 0.073 af Inflow=0.10 cfs 0.004 afPond 6P: Offsite to West Primary=0.10 cfs 0.004 af Inflow=1.79 cfs 0.096 afPond 9P: Offsite to North Primary=1.79 cfs 0.096 af Total Runoff Area = 0.793 ac Runoff Volume = 0.100 af Average Runoff Depth = 1.51" 55.19% Pervious = 0.438 ac 44.81% Impervious = 0.355 ac MSE 24-hr 3 2-year Rainfall=2.80"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 6HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Summary for Subcatchment 2S: Area 1 Runoff = 0.44 cfs @ 12.18 hrs, Volume= 0.023 af, Depth> 1.10" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs MSE 24-hr 3 2-year Rainfall=2.80" Area (sf) CN Description 3,266 96 Gravel surface, HSG C 7,583 74 >75% Grass cover, Good, HSG C 10,849 81 Weighted Average 10,849 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Subcatchment 2S: Area 1 Runoff Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)0.48 0.46 0.44 0.42 0.4 0.38 0.36 0.34 0.32 0.3 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 MSE 24-hr 3 2-year Rainfall=2.80" Runoff Area=10,849 sf Runoff Volume=0.023 af Runoff Depth>1.10" Tc=10.0 min CN=81 0.44 cfs MSE 24-hr 3 2-year Rainfall=2.80"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 7HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Summary for Subcatchment 3S: Area 2 Runoff = 1.35 cfs @ 12.17 hrs, Volume= 0.073 af, Depth> 1.81" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs MSE 24-hr 3 2-year Rainfall=2.80" Area (sf) CN Description 15,236 98 Paved parking, HSG C 5,737 74 >75% Grass cover, Good, HSG C 20,973 91 Weighted Average 5,737 27.35% Pervious Area 15,236 72.65% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Subcatchment 3S: Area 2 Runoff Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)1 0 MSE 24-hr 3 2-year Rainfall=2.80" Runoff Area=20,973 sf Runoff Volume=0.073 af Runoff Depth>1.81" Tc=10.0 min CN=91 1.35 cfs MSE 24-hr 3 2-year Rainfall=2.80"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 8HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Summary for Subcatchment 4S: Area 3 [49] Hint: Tc<2dt may require smaller dt Runoff = 0.10 cfs @ 12.13 hrs, Volume= 0.004 af, Depth> 0.83" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs MSE 24-hr 3 2-year Rainfall=2.80" Area (sf) CN Description 245 98 Paved parking, HSG C 2,479 74 >75% Grass cover, Good, HSG C 2,724 76 Weighted Average 2,479 91.01% Pervious Area 245 8.99% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment 4S: Area 3 Runoff Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)0.11 0.105 0.1 0.095 0.09 0.085 0.08 0.075 0.07 0.065 0.06 0.055 0.05 0.045 0.04 0.035 0.03 0.025 0.02 0.015 0.01 0.005 0 MSE 24-hr 3 2-year Rainfall=2.80" Runoff Area=2,724 sf Runoff Volume=0.004 af Runoff Depth>0.83" Tc=5.0 min CN=76 0.10 cfs MSE 24-hr 3 2-year Rainfall=2.80"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 9HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Summary for Pond 1P: Offsite to Gas Station [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 0.249 ac, 0.00% Impervious, Inflow Depth > 1.10" for 2-year event Inflow = 0.44 cfs @ 12.18 hrs, Volume= 0.023 af Primary = 0.44 cfs @ 12.18 hrs, Volume= 0.023 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Pond 1P: Offsite to Gas Station Inflow Primary Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)0.48 0.46 0.44 0.42 0.4 0.38 0.36 0.34 0.32 0.3 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 Inflow Area=0.249 ac 0.44 cfs 0.44 cfs MSE 24-hr 3 2-year Rainfall=2.80"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 10HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Summary for Pond 5P: Offsite to Frontage [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 0.481 ac, 72.65% Impervious, Inflow Depth > 1.81" for 2-year event Inflow = 1.35 cfs @ 12.17 hrs, Volume= 0.073 af Primary = 1.35 cfs @ 12.17 hrs, Volume= 0.073 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Pond 5P: Offsite to Frontage Inflow Primary Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)1 0 Inflow Area=0.481 ac 1.35 cfs 1.35 cfs MSE 24-hr 3 2-year Rainfall=2.80"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 11HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Summary for Pond 6P: Offsite to West [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 0.063 ac, 8.99% Impervious, Inflow Depth > 0.83" for 2-year event Inflow = 0.10 cfs @ 12.13 hrs, Volume= 0.004 af Primary = 0.10 cfs @ 12.13 hrs, Volume= 0.004 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Pond 6P: Offsite to West Inflow Primary Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)0.11 0.105 0.1 0.095 0.09 0.085 0.08 0.075 0.07 0.065 0.06 0.055 0.05 0.045 0.04 0.035 0.03 0.025 0.02 0.015 0.01 0.005 0 Inflow Area=0.063 ac 0.10 cfs 0.10 cfs MSE 24-hr 3 2-year Rainfall=2.80"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 12HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Summary for Pond 9P: Offsite to North [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 0.731 ac, 47.88% Impervious, Inflow Depth > 1.57" for 2-year event Inflow = 1.79 cfs @ 12.18 hrs, Volume= 0.096 af Primary = 1.79 cfs @ 12.18 hrs, Volume= 0.096 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Pond 9P: Offsite to North Inflow Primary Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)2 1 0 Inflow Area=0.731 ac 1.79 cfs 1.79 cfs MSE 24-hr 3 10-year Rainfall=4.20"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 13HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Time span=5.00-20.00 hrs, dt=0.05 hrs, 301 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=10,849 sf 0.00% Impervious Runoff Depth>2.19"Subcatchment 2S: Area 1 Tc=10.0 min CN=81 Runoff=0.86 cfs 0.046 af Runoff Area=20,973 sf 72.65% Impervious Runoff Depth>3.10"Subcatchment 3S: Area 2 Tc=10.0 min CN=91 Runoff=2.24 cfs 0.124 af Runoff Area=2,724 sf 8.99% Impervious Runoff Depth>1.81"Subcatchment 4S: Area 3 Tc=5.0 min CN=76 Runoff=0.22 cfs 0.009 af Inflow=0.86 cfs 0.046 afPond 1P: Offsite to Gas Station Primary=0.86 cfs 0.046 af Inflow=2.24 cfs 0.124 afPond 5P: Offsite to Frontage Primary=2.24 cfs 0.124 af Inflow=0.22 cfs 0.009 afPond 6P: Offsite to West Primary=0.22 cfs 0.009 af Inflow=3.11 cfs 0.170 afPond 9P: Offsite to North Primary=3.11 cfs 0.170 af Total Runoff Area = 0.793 ac Runoff Volume = 0.179 af Average Runoff Depth = 2.71" 55.19% Pervious = 0.438 ac 44.81% Impervious = 0.355 ac MSE 24-hr 3 10-year Rainfall=4.20"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 14HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Summary for Subcatchment 2S: Area 1 Runoff = 0.86 cfs @ 12.18 hrs, Volume= 0.046 af, Depth> 2.19" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs MSE 24-hr 3 10-year Rainfall=4.20" Area (sf) CN Description 3,266 96 Gravel surface, HSG C 7,583 74 >75% Grass cover, Good, HSG C 10,849 81 Weighted Average 10,849 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Subcatchment 2S: Area 1 Runoff Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)0.95 0.9 0.85 0.8 0.75 0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 MSE 24-hr 3 10-year Rainfall=4.20" Runoff Area=10,849 sf Runoff Volume=0.046 af Runoff Depth>2.19" Tc=10.0 min CN=81 0.86 cfs MSE 24-hr 3 10-year Rainfall=4.20"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 15HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Summary for Subcatchment 3S: Area 2 Runoff = 2.24 cfs @ 12.17 hrs, Volume= 0.124 af, Depth> 3.10" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs MSE 24-hr 3 10-year Rainfall=4.20" Area (sf) CN Description 15,236 98 Paved parking, HSG C 5,737 74 >75% Grass cover, Good, HSG C 20,973 91 Weighted Average 5,737 27.35% Pervious Area 15,236 72.65% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Subcatchment 3S: Area 2 Runoff Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)2 1 0 MSE 24-hr 3 10-year Rainfall=4.20" Runoff Area=20,973 sf Runoff Volume=0.124 af Runoff Depth>3.10" Tc=10.0 min CN=91 2.24 cfs MSE 24-hr 3 10-year Rainfall=4.20"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 16HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Summary for Subcatchment 4S: Area 3 [49] Hint: Tc<2dt may require smaller dt Runoff = 0.22 cfs @ 12.12 hrs, Volume= 0.009 af, Depth> 1.81" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs MSE 24-hr 3 10-year Rainfall=4.20" Area (sf) CN Description 245 98 Paved parking, HSG C 2,479 74 >75% Grass cover, Good, HSG C 2,724 76 Weighted Average 2,479 91.01% Pervious Area 245 8.99% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment 4S: Area 3 Runoff Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)0.24 0.23 0.22 0.21 0.2 0.19 0.18 0.17 0.16 0.15 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 MSE 24-hr 3 10-year Rainfall=4.20" Runoff Area=2,724 sf Runoff Volume=0.009 af Runoff Depth>1.81" Tc=5.0 min CN=76 0.22 cfs MSE 24-hr 3 10-year Rainfall=4.20"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 17HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Summary for Pond 1P: Offsite to Gas Station [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 0.249 ac, 0.00% Impervious, Inflow Depth > 2.19" for 10-year event Inflow = 0.86 cfs @ 12.18 hrs, Volume= 0.046 af Primary = 0.86 cfs @ 12.18 hrs, Volume= 0.046 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Pond 1P: Offsite to Gas Station Inflow Primary Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)0.95 0.9 0.85 0.8 0.75 0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Inflow Area=0.249 ac 0.86 cfs 0.86 cfs MSE 24-hr 3 10-year Rainfall=4.20"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 18HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Summary for Pond 5P: Offsite to Frontage [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 0.481 ac, 72.65% Impervious, Inflow Depth > 3.10" for 10-year event Inflow = 2.24 cfs @ 12.17 hrs, Volume= 0.124 af Primary = 2.24 cfs @ 12.17 hrs, Volume= 0.124 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Pond 5P: Offsite to Frontage Inflow Primary Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)2 1 0 Inflow Area=0.481 ac 2.24 cfs 2.24 cfs MSE 24-hr 3 10-year Rainfall=4.20"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 19HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Summary for Pond 6P: Offsite to West [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 0.063 ac, 8.99% Impervious, Inflow Depth > 1.81" for 10-year event Inflow = 0.22 cfs @ 12.12 hrs, Volume= 0.009 af Primary = 0.22 cfs @ 12.12 hrs, Volume= 0.009 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Pond 6P: Offsite to West Inflow Primary Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)0.24 0.23 0.22 0.21 0.2 0.19 0.18 0.17 0.16 0.15 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 Inflow Area=0.063 ac 0.22 cfs 0.22 cfs MSE 24-hr 3 10-year Rainfall=4.20"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 20HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Summary for Pond 9P: Offsite to North [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 0.731 ac, 47.88% Impervious, Inflow Depth > 2.79" for 10-year event Inflow = 3.11 cfs @ 12.17 hrs, Volume= 0.170 af Primary = 3.11 cfs @ 12.17 hrs, Volume= 0.170 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Pond 9P: Offsite to North Inflow Primary Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)3 2 1 0 Inflow Area=0.731 ac 3.11 cfs 3.11 cfs MSE 24-hr 3 100-year Rainfall=7.30"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 21HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Time span=5.00-20.00 hrs, dt=0.05 hrs, 301 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=10,849 sf 0.00% Impervious Runoff Depth>4.90"Subcatchment 2S: Area 1 Tc=10.0 min CN=81 Runoff=1.88 cfs 0.102 af Runoff Area=20,973 sf 72.65% Impervious Runoff Depth>6.03"Subcatchment 3S: Area 2 Tc=10.0 min CN=91 Runoff=4.19 cfs 0.242 af Runoff Area=2,724 sf 8.99% Impervious Runoff Depth>4.35"Subcatchment 4S: Area 3 Tc=5.0 min CN=76 Runoff=0.51 cfs 0.023 af Inflow=1.88 cfs 0.102 afPond 1P: Offsite to Gas Station Primary=1.88 cfs 0.102 af Inflow=4.19 cfs 0.242 afPond 5P: Offsite to Frontage Primary=4.19 cfs 0.242 af Inflow=0.51 cfs 0.023 afPond 6P: Offsite to West Primary=0.51 cfs 0.023 af Inflow=6.07 cfs 0.344 afPond 9P: Offsite to North Primary=6.07 cfs 0.344 af Total Runoff Area = 0.793 ac Runoff Volume = 0.366 af Average Runoff Depth = 5.54" 55.19% Pervious = 0.438 ac 44.81% Impervious = 0.355 ac MSE 24-hr 3 100-year Rainfall=7.30"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 22HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Summary for Subcatchment 2S: Area 1 Runoff = 1.88 cfs @ 12.17 hrs, Volume= 0.102 af, Depth> 4.90" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs MSE 24-hr 3 100-year Rainfall=7.30" Area (sf) CN Description 3,266 96 Gravel surface, HSG C 7,583 74 >75% Grass cover, Good, HSG C 10,849 81 Weighted Average 10,849 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Subcatchment 2S: Area 1 Runoff Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)2 1 0 MSE 24-hr 3 100-year Rainfall=7.30" Runoff Area=10,849 sf Runoff Volume=0.102 af Runoff Depth>4.90" Tc=10.0 min CN=81 1.88 cfs MSE 24-hr 3 100-year Rainfall=7.30"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 23HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Summary for Subcatchment 3S: Area 2 Runoff = 4.19 cfs @ 12.17 hrs, Volume= 0.242 af, Depth> 6.03" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs MSE 24-hr 3 100-year Rainfall=7.30" Area (sf) CN Description 15,236 98 Paved parking, HSG C 5,737 74 >75% Grass cover, Good, HSG C 20,973 91 Weighted Average 5,737 27.35% Pervious Area 15,236 72.65% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Subcatchment 3S: Area 2 Runoff Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)4 3 2 1 0 MSE 24-hr 3 100-year Rainfall=7.30" Runoff Area=20,973 sf Runoff Volume=0.242 af Runoff Depth>6.03" Tc=10.0 min CN=91 4.19 cfs MSE 24-hr 3 100-year Rainfall=7.30"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 24HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Summary for Subcatchment 4S: Area 3 [49] Hint: Tc<2dt may require smaller dt Runoff = 0.51 cfs @ 12.12 hrs, Volume= 0.023 af, Depth> 4.35" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs MSE 24-hr 3 100-year Rainfall=7.30" Area (sf) CN Description 245 98 Paved parking, HSG C 2,479 74 >75% Grass cover, Good, HSG C 2,724 76 Weighted Average 2,479 91.01% Pervious Area 245 8.99% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment 4S: Area 3 Runoff Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 MSE 24-hr 3 100-year Rainfall=7.30" Runoff Area=2,724 sf Runoff Volume=0.023 af Runoff Depth>4.35" Tc=5.0 min CN=76 0.51 cfs MSE 24-hr 3 100-year Rainfall=7.30"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 25HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Summary for Pond 1P: Offsite to Gas Station [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 0.249 ac, 0.00% Impervious, Inflow Depth > 4.90" for 100-year event Inflow = 1.88 cfs @ 12.17 hrs, Volume= 0.102 af Primary = 1.88 cfs @ 12.17 hrs, Volume= 0.102 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Pond 1P: Offsite to Gas Station Inflow Primary Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)2 1 0 Inflow Area=0.249 ac 1.88 cfs 1.88 cfs MSE 24-hr 3 100-year Rainfall=7.30"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 26HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Summary for Pond 5P: Offsite to Frontage [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 0.481 ac, 72.65% Impervious, Inflow Depth > 6.03" for 100-year event Inflow = 4.19 cfs @ 12.17 hrs, Volume= 0.242 af Primary = 4.19 cfs @ 12.17 hrs, Volume= 0.242 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Pond 5P: Offsite to Frontage Inflow Primary Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)4 3 2 1 0 Inflow Area=0.481 ac 4.19 cfs 4.19 cfs MSE 24-hr 3 100-year Rainfall=7.30"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 27HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Summary for Pond 6P: Offsite to West [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 0.063 ac, 8.99% Impervious, Inflow Depth > 4.35" for 100-year event Inflow = 0.51 cfs @ 12.12 hrs, Volume= 0.023 af Primary = 0.51 cfs @ 12.12 hrs, Volume= 0.023 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Pond 6P: Offsite to West Inflow Primary Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Inflow Area=0.063 ac 0.51 cfs 0.51 cfs MSE 24-hr 3 100-year Rainfall=7.30"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 28HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Summary for Pond 9P: Offsite to North [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 0.731 ac, 47.88% Impervious, Inflow Depth > 5.65" for 100-year event Inflow = 6.07 cfs @ 12.17 hrs, Volume= 0.344 af Primary = 6.07 cfs @ 12.17 hrs, Volume= 0.344 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Pond 9P: Offsite to North Inflow Primary Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)6 5 4 3 2 1 0 Inflow Area=0.731 ac 6.07 cfs 6.07 cfs Proposed conditions 9S Area 1 10S Area 2 11S Area 3 10P Offsite to North 11P Raingarden B2 12P Raingarden B1 13P Offsite to Frontage 14P Offsite to West Routing Diagram for Tire Pros Prepared by Stevens Engineers, Printed 8/16/2022 HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Subcat Reach Pond Link Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 2HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Area Listing (selected nodes) Area (acres) CN Description (subcatchment-numbers) 0.243 74 >75% Grass cover, Good, HSG C (9S, 10S, 11S) 0.550 98 Paved parking, HSG C (9S, 10S, 11S) 0.794 91 TOTAL AREA Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 3HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Soil Listing (selected nodes) Area (acres) Soil Group Subcatchment Numbers 0.000 HSG A 0.000 HSG B 0.794 HSG C 9S, 10S, 11S 0.000 HSG D 0.000 Other 0.794 TOTAL AREA Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 4HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Ground Covers (selected nodes) HSG-A (acres) HSG-B (acres) HSG-C (acres) HSG-D (acres) Other (acres) Total (acres) Ground Cover Subcatchment Numbers 0.000 0.000 0.243 0.000 0.000 0.243 >75% Grass cover, Good 9S, 10S, 11S 0.000 0.000 0.550 0.000 0.000 0.550 Paved parking 9S, 10S, 11S 0.000 0.000 0.794 0.000 0.000 0.794 TOTAL AREA Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 5HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Pipe Listing (selected nodes) Line# Node Number In-Invert (feet) Out-Invert (feet) Length (feet) Slope (ft/ft) n Diam/Width (inches) Height (inches) Inside-Fill (inches) 1 11P 904.50 904.40 10.0 0.0100 0.012 12.0 0.0 0.0 2 12P 906.50 906.00 213.0 0.0023 0.012 12.0 0.0 0.0 MSE 24-hr 3 2-year Rainfall=2.80"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 6HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Time span=5.00-20.00 hrs, dt=0.05 hrs, 301 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=14,934 sf 64.96% Impervious Runoff Depth>1.73"Subcatchment 9S: Area 1 Tc=10.0 min CN=90 Runoff=0.92 cfs 0.049 af Runoff Area=16,890 sf 82.99% Impervious Runoff Depth>2.08"Subcatchment 10S: Area 2 Tc=10.0 min CN=94 Runoff=1.21 cfs 0.067 af Runoff Area=2,747 sf 9.25% Impervious Runoff Depth>0.83"Subcatchment 11S: Area 3 Tc=5.0 min CN=76 Runoff=0.10 cfs 0.004 af Inflow=1.47 cfs 0.098 afPond 10P: Offsite to North Primary=1.47 cfs 0.098 af Peak Elev=907.15' Storage=211 cf Inflow=1.21 cfs 0.067 afPond 11P: Raingarden B2 Outflow=1.21 cfs 0.063 af Peak Elev=909.73' Storage=912 cf Inflow=0.92 cfs 0.049 afPond 12P: Raingarden B1 Primary=0.46 cfs 0.035 af Secondary=0.00 cfs 0.000 af Outflow=0.46 cfs 0.035 af Inflow=1.47 cfs 0.098 afPond 13P: Offsite to Frontage Primary=1.47 cfs 0.098 af Inflow=0.10 cfs 0.004 afPond 14P: Offsite to West Primary=0.10 cfs 0.004 af Total Runoff Area = 0.794 ac Runoff Volume = 0.121 af Average Runoff Depth = 1.83" 30.66% Pervious = 0.243 ac 69.34% Impervious = 0.550 ac MSE 24-hr 3 2-year Rainfall=2.80"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 7HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Summary for Subcatchment 9S: Area 1 Runoff = 0.92 cfs @ 12.18 hrs, Volume= 0.049 af, Depth> 1.73" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs MSE 24-hr 3 2-year Rainfall=2.80" Area (sf) CN Description 9,701 98 Paved parking, HSG C 5,233 74 >75% Grass cover, Good, HSG C 14,934 90 Weighted Average 5,233 35.04% Pervious Area 9,701 64.96% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Subcatchment 9S: Area 1 Runoff Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)1 0 MSE 24-hr 3 2-year Rainfall=2.80" Runoff Area=14,934 sf Runoff Volume=0.049 af Runoff Depth>1.73" Tc=10.0 min CN=90 0.92 cfs MSE 24-hr 3 2-year Rainfall=2.80"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 8HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Summary for Subcatchment 10S: Area 2 Runoff = 1.21 cfs @ 12.17 hrs, Volume= 0.067 af, Depth> 2.08" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs MSE 24-hr 3 2-year Rainfall=2.80" Area (sf) CN Description 14,017 98 Paved parking, HSG C 2,873 74 >75% Grass cover, Good, HSG C 16,890 94 Weighted Average 2,873 17.01% Pervious Area 14,017 82.99% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Subcatchment 10S: Area 2 Runoff Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)1 0 MSE 24-hr 3 2-year Rainfall=2.80" Runoff Area=16,890 sf Runoff Volume=0.067 af Runoff Depth>2.08" Tc=10.0 min CN=94 1.21 cfs MSE 24-hr 3 2-year Rainfall=2.80"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 9HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Summary for Subcatchment 11S: Area 3 [49] Hint: Tc<2dt may require smaller dt Runoff = 0.10 cfs @ 12.13 hrs, Volume= 0.004 af, Depth> 0.83" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs MSE 24-hr 3 2-year Rainfall=2.80" Area (sf) CN Description 254 98 Paved parking, HSG C 2,493 74 >75% Grass cover, Good, HSG C 2,747 76 Weighted Average 2,493 90.75% Pervious Area 254 9.25% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment 11S: Area 3 Runoff Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)0.11 0.105 0.1 0.095 0.09 0.085 0.08 0.075 0.07 0.065 0.06 0.055 0.05 0.045 0.04 0.035 0.03 0.025 0.02 0.015 0.01 0.005 0 MSE 24-hr 3 2-year Rainfall=2.80" Runoff Area=2,747 sf Runoff Volume=0.004 af Runoff Depth>0.83" Tc=5.0 min CN=76 0.10 cfs MSE 24-hr 3 2-year Rainfall=2.80"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 10HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Summary for Pond 10P: Offsite to North [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 0.731 ac, 74.53% Impervious, Inflow Depth > 1.61" for 2-year event Inflow = 1.47 cfs @ 12.22 hrs, Volume= 0.098 af Primary = 1.47 cfs @ 12.22 hrs, Volume= 0.098 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Pond 10P: Offsite to North Inflow Primary Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)1 0 Inflow Area=0.731 ac 1.47 cfs 1.47 cfs MSE 24-hr 3 2-year Rainfall=2.80"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 11HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Summary for Pond 11P: Raingarden B2 Inflow Area = 0.388 ac, 82.99% Impervious, Inflow Depth > 2.08" for 2-year event Inflow = 1.21 cfs @ 12.17 hrs, Volume= 0.067 af Outflow = 1.21 cfs @ 12.18 hrs, Volume= 0.063 af, Atten= 0%, Lag= 0.6 min Primary = 1.21 cfs @ 12.18 hrs, Volume= 0.063 af Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Peak Elev= 907.15' @ 12.18 hrs Surf.Area= 277 sf Storage= 211 cf Plug-Flow detention time= 31.4 min calculated for 0.063 af (94% of inflow) Center-of-Mass det. time= 11.3 min ( 774.7 - 763.5 ) Volume Invert Avail.Storage Storage Description #1 906.00' 393 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 906.00 95 0 0 907.00 247 171 171 907.70 388 222 393 Device Routing Invert Outlet Devices #1 Primary 904.50'12.0" Round Culvert L= 10.0' CPP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 904.50' / 904.40' S= 0.0100 '/' Cc= 0.900 n= 0.012 Concrete pipe, finished, Flow Area= 0.79 sf #2 Device 1 906.00'0.500 in/hr Exfiltration over Surface area #3 Device 1 907.00'2.0" x 18.0" Horiz. Orifice/Grate X 4 rows C= 0.600 in 24.0" Grate (32% open area) Limited to weir flow at low heads Primary OutFlow Max=1.18 cfs @ 12.18 hrs HW=907.15' (Free Discharge) 1=Culvert (Passes 1.18 cfs of 4.38 cfs potential flow) 2=Exfiltration (Exfiltration Controls 0.00 cfs) 3=Orifice/Grate (Weir Controls 1.17 cfs @ 1.26 fps) MSE 24-hr 3 2-year Rainfall=2.80"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 12HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Pond 11P: Raingarden B2 Inflow Primary Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)1 0 Inflow Area=0.388 ac Peak Elev=907.15' Storage=211 cf 1.21 cfs 1.21 cfs MSE 24-hr 3 2-year Rainfall=2.80"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 13HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Summary for Pond 12P: Raingarden B1 Inflow Area = 0.343 ac, 64.96% Impervious, Inflow Depth > 1.73" for 2-year event Inflow = 0.92 cfs @ 12.18 hrs, Volume= 0.049 af Outflow = 0.46 cfs @ 12.32 hrs, Volume= 0.035 af, Atten= 50%, Lag= 9.0 min Primary = 0.46 cfs @ 12.32 hrs, Volume= 0.035 af Secondary = 0.00 cfs @ 5.00 hrs, Volume= 0.000 af Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Peak Elev= 909.73' @ 12.32 hrs Surf.Area= 1,259 sf Storage= 912 cf Plug-Flow detention time= 92.7 min calculated for 0.035 af (70% of inflow) Center-of-Mass det. time= 40.9 min ( 817.1 - 776.2 ) Volume Invert Avail.Storage Storage Description #1 908.50' 2,141 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 908.50 231 0 0 909.50 1,066 649 649 910.50 1,918 1,492 2,141 Device Routing Invert Outlet Devices #1 Primary 906.50'12.0" Round Culvert L= 213.0' CPP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 906.50' / 906.00' S= 0.0023 '/' Cc= 0.900 n= 0.012 Concrete pipe, finished, Flow Area= 0.79 sf #2 Device 1 908.50'0.500 in/hr Exfiltration over Surface area #3 Secondary 909.80'2.0' long x 2.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 Coef. (English) 2.54 2.61 2.61 2.60 2.66 2.70 2.77 2.89 2.88 2.85 3.07 3.20 3.32 #4 Device 1 909.50'6.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads Primary OutFlow Max=0.46 cfs @ 12.32 hrs HW=909.72' (Free Discharge) 1=Culvert (Passes 0.46 cfs of 3.77 cfs potential flow) 2=Exfiltration (Exfiltration Controls 0.01 cfs) 4=Orifice/Grate (Orifice Controls 0.45 cfs @ 2.28 fps) Secondary OutFlow Max=0.00 cfs @ 5.00 hrs HW=908.50' (Free Discharge) 3=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) MSE 24-hr 3 2-year Rainfall=2.80"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 14HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Pond 12P: Raingarden B1 Inflow Outflow Primary Secondary Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)1 0 Inflow Area=0.343 ac Peak Elev=909.73' Storage=912 cf 0.92 cfs 0.46 cfs 0.46 cfs 0.00 cfs MSE 24-hr 3 2-year Rainfall=2.80"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 15HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Summary for Pond 13P: Offsite to Frontage [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 0.731 ac, 74.53% Impervious, Inflow Depth > 1.61" for 2-year event Inflow = 1.47 cfs @ 12.22 hrs, Volume= 0.098 af Primary = 1.47 cfs @ 12.22 hrs, Volume= 0.098 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Pond 13P: Offsite to Frontage Inflow Primary Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)1 0 Inflow Area=0.731 ac 1.47 cfs 1.47 cfs MSE 24-hr 3 2-year Rainfall=2.80"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 16HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Summary for Pond 14P: Offsite to West [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 0.063 ac, 9.25% Impervious, Inflow Depth > 0.83" for 2-year event Inflow = 0.10 cfs @ 12.13 hrs, Volume= 0.004 af Primary = 0.10 cfs @ 12.13 hrs, Volume= 0.004 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Pond 14P: Offsite to West Inflow Primary Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)0.11 0.105 0.1 0.095 0.09 0.085 0.08 0.075 0.07 0.065 0.06 0.055 0.05 0.045 0.04 0.035 0.03 0.025 0.02 0.015 0.01 0.005 0 Inflow Area=0.063 ac 0.10 cfs 0.10 cfs MSE 24-hr 3 10-year Rainfall=4.20"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 17HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Time span=5.00-20.00 hrs, dt=0.05 hrs, 301 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=14,934 sf 64.96% Impervious Runoff Depth>3.00"Subcatchment 9S: Area 1 Tc=10.0 min CN=90 Runoff=1.56 cfs 0.086 af Runoff Area=16,890 sf 82.99% Impervious Runoff Depth>3.41"Subcatchment 10S: Area 2 Tc=10.0 min CN=94 Runoff=1.92 cfs 0.110 af Runoff Area=2,747 sf 9.25% Impervious Runoff Depth>1.81"Subcatchment 11S: Area 3 Tc=5.0 min CN=76 Runoff=0.22 cfs 0.009 af Inflow=2.81 cfs 0.177 afPond 10P: Offsite to North Primary=2.81 cfs 0.177 af Peak Elev=907.21' Storage=226 cf Inflow=1.92 cfs 0.110 afPond 11P: Raingarden B2 Outflow=1.92 cfs 0.106 af Peak Elev=909.99' Storage=1,273 cf Inflow=1.56 cfs 0.086 afPond 12P: Raingarden B1 Primary=0.68 cfs 0.063 af Secondary=0.42 cfs 0.007 af Outflow=1.10 cfs 0.071 af Inflow=2.81 cfs 0.177 afPond 13P: Offsite to Frontage Primary=2.81 cfs 0.177 af Inflow=0.22 cfs 0.009 afPond 14P: Offsite to West Primary=0.22 cfs 0.009 af Total Runoff Area = 0.794 ac Runoff Volume = 0.205 af Average Runoff Depth = 3.10" 30.66% Pervious = 0.243 ac 69.34% Impervious = 0.550 ac MSE 24-hr 3 10-year Rainfall=4.20"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 18HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Summary for Subcatchment 9S: Area 1 Runoff = 1.56 cfs @ 12.17 hrs, Volume= 0.086 af, Depth> 3.00" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs MSE 24-hr 3 10-year Rainfall=4.20" Area (sf) CN Description 9,701 98 Paved parking, HSG C 5,233 74 >75% Grass cover, Good, HSG C 14,934 90 Weighted Average 5,233 35.04% Pervious Area 9,701 64.96% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Subcatchment 9S: Area 1 Runoff Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)1 0 MSE 24-hr 3 10-year Rainfall=4.20" Runoff Area=14,934 sf Runoff Volume=0.086 af Runoff Depth>3.00" Tc=10.0 min CN=90 1.56 cfs MSE 24-hr 3 10-year Rainfall=4.20"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 19HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Summary for Subcatchment 10S: Area 2 Runoff = 1.92 cfs @ 12.17 hrs, Volume= 0.110 af, Depth> 3.41" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs MSE 24-hr 3 10-year Rainfall=4.20" Area (sf) CN Description 14,017 98 Paved parking, HSG C 2,873 74 >75% Grass cover, Good, HSG C 16,890 94 Weighted Average 2,873 17.01% Pervious Area 14,017 82.99% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Subcatchment 10S: Area 2 Runoff Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)2 1 0 MSE 24-hr 3 10-year Rainfall=4.20" Runoff Area=16,890 sf Runoff Volume=0.110 af Runoff Depth>3.41" Tc=10.0 min CN=94 1.92 cfs MSE 24-hr 3 10-year Rainfall=4.20"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 20HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Summary for Subcatchment 11S: Area 3 [49] Hint: Tc<2dt may require smaller dt Runoff = 0.22 cfs @ 12.12 hrs, Volume= 0.009 af, Depth> 1.81" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs MSE 24-hr 3 10-year Rainfall=4.20" Area (sf) CN Description 254 98 Paved parking, HSG C 2,493 74 >75% Grass cover, Good, HSG C 2,747 76 Weighted Average 2,493 90.75% Pervious Area 254 9.25% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment 11S: Area 3 Runoff Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)0.24 0.23 0.22 0.21 0.2 0.19 0.18 0.17 0.16 0.15 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 MSE 24-hr 3 10-year Rainfall=4.20" Runoff Area=2,747 sf Runoff Volume=0.009 af Runoff Depth>1.81" Tc=5.0 min CN=76 0.22 cfs MSE 24-hr 3 10-year Rainfall=4.20"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 21HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Summary for Pond 10P: Offsite to North [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 0.731 ac, 74.53% Impervious, Inflow Depth > 2.90" for 10-year event Inflow = 2.81 cfs @ 12.20 hrs, Volume= 0.177 af Primary = 2.81 cfs @ 12.20 hrs, Volume= 0.177 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Pond 10P: Offsite to North Inflow Primary Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)3 2 1 0 Inflow Area=0.731 ac 2.81 cfs 2.81 cfs MSE 24-hr 3 10-year Rainfall=4.20"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 22HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Summary for Pond 11P: Raingarden B2 Inflow Area = 0.388 ac, 82.99% Impervious, Inflow Depth > 3.41" for 10-year event Inflow = 1.92 cfs @ 12.17 hrs, Volume= 0.110 af Outflow = 1.92 cfs @ 12.18 hrs, Volume= 0.106 af, Atten= 0%, Lag= 0.5 min Primary = 1.92 cfs @ 12.18 hrs, Volume= 0.106 af Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Peak Elev= 907.21' @ 12.18 hrs Surf.Area= 288 sf Storage= 226 cf Plug-Flow detention time= 24.1 min calculated for 0.106 af (96% of inflow) Center-of-Mass det. time= 10.2 min ( 765.1 - 755.0 ) Volume Invert Avail.Storage Storage Description #1 906.00' 393 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 906.00 95 0 0 907.00 247 171 171 907.70 388 222 393 Device Routing Invert Outlet Devices #1 Primary 904.50'12.0" Round Culvert L= 10.0' CPP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 904.50' / 904.40' S= 0.0100 '/' Cc= 0.900 n= 0.012 Concrete pipe, finished, Flow Area= 0.79 sf #2 Device 1 906.00'0.500 in/hr Exfiltration over Surface area #3 Device 1 907.00'2.0" x 18.0" Horiz. Orifice/Grate X 4 rows C= 0.600 in 24.0" Grate (32% open area) Limited to weir flow at low heads Primary OutFlow Max=1.86 cfs @ 12.18 hrs HW=907.20' (Free Discharge) 1=Culvert (Passes 1.86 cfs of 4.43 cfs potential flow) 2=Exfiltration (Exfiltration Controls 0.00 cfs) 3=Orifice/Grate (Weir Controls 1.86 cfs @ 1.47 fps) MSE 24-hr 3 10-year Rainfall=4.20"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 23HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Pond 11P: Raingarden B2 Inflow Primary Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)2 1 0 Inflow Area=0.388 ac Peak Elev=907.21' Storage=226 cf 1.92 cfs 1.92 cfs MSE 24-hr 3 10-year Rainfall=4.20"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 24HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Summary for Pond 12P: Raingarden B1 Inflow Area = 0.343 ac, 64.96% Impervious, Inflow Depth > 3.00" for 10-year event Inflow = 1.56 cfs @ 12.17 hrs, Volume= 0.086 af Outflow = 1.10 cfs @ 12.27 hrs, Volume= 0.071 af, Atten= 30%, Lag= 5.7 min Primary = 0.68 cfs @ 12.27 hrs, Volume= 0.063 af Secondary = 0.42 cfs @ 12.27 hrs, Volume= 0.007 af Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Peak Elev= 909.99' @ 12.27 hrs Surf.Area= 1,483 sf Storage= 1,273 cf Plug-Flow detention time= 69.7 min calculated for 0.070 af (82% of inflow) Center-of-Mass det. time= 29.0 min ( 795.8 - 766.8 ) Volume Invert Avail.Storage Storage Description #1 908.50' 2,141 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 908.50 231 0 0 909.50 1,066 649 649 910.50 1,918 1,492 2,141 Device Routing Invert Outlet Devices #1 Primary 906.50'12.0" Round Culvert L= 213.0' CPP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 906.50' / 906.00' S= 0.0023 '/' Cc= 0.900 n= 0.012 Concrete pipe, finished, Flow Area= 0.79 sf #2 Device 1 908.50'0.500 in/hr Exfiltration over Surface area #3 Secondary 909.80'2.0' long x 2.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 Coef. (English) 2.54 2.61 2.61 2.60 2.66 2.70 2.77 2.89 2.88 2.85 3.07 3.20 3.32 #4 Device 1 909.50'6.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads Primary OutFlow Max=0.68 cfs @ 12.27 hrs HW=909.98' (Free Discharge) 1=Culvert (Passes 0.68 cfs of 3.95 cfs potential flow) 2=Exfiltration (Exfiltration Controls 0.02 cfs) 4=Orifice/Grate (Orifice Controls 0.66 cfs @ 3.35 fps) Secondary OutFlow Max=0.40 cfs @ 12.27 hrs HW=909.98' (Free Discharge) 3=Broad-Crested Rectangular Weir (Weir Controls 0.40 cfs @ 1.09 fps) MSE 24-hr 3 10-year Rainfall=4.20"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 25HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Pond 12P: Raingarden B1 Inflow Outflow Primary Secondary Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)1 0 Inflow Area=0.343 ac Peak Elev=909.99' Storage=1,273 cf 1.56 cfs 1.10 cfs 0.68 cfs 0.42 cfs MSE 24-hr 3 10-year Rainfall=4.20"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 26HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Summary for Pond 13P: Offsite to Frontage [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 0.731 ac, 74.53% Impervious, Inflow Depth > 2.90" for 10-year event Inflow = 2.81 cfs @ 12.20 hrs, Volume= 0.177 af Primary = 2.81 cfs @ 12.20 hrs, Volume= 0.177 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Pond 13P: Offsite to Frontage Inflow Primary Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)3 2 1 0 Inflow Area=0.731 ac 2.81 cfs 2.81 cfs MSE 24-hr 3 10-year Rainfall=4.20"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 27HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Summary for Pond 14P: Offsite to West [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 0.063 ac, 9.25% Impervious, Inflow Depth > 1.81" for 10-year event Inflow = 0.22 cfs @ 12.12 hrs, Volume= 0.009 af Primary = 0.22 cfs @ 12.12 hrs, Volume= 0.009 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Pond 14P: Offsite to West Inflow Primary Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)0.24 0.23 0.22 0.21 0.2 0.19 0.18 0.17 0.16 0.15 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 Inflow Area=0.063 ac 0.22 cfs 0.22 cfs MSE 24-hr 3 100-year Rainfall=7.30"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 28HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Time span=5.00-20.00 hrs, dt=0.05 hrs, 301 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=14,934 sf 64.96% Impervious Runoff Depth>5.92"Subcatchment 9S: Area 1 Tc=10.0 min CN=90 Runoff=2.95 cfs 0.169 af Runoff Area=16,890 sf 82.99% Impervious Runoff Depth>6.36"Subcatchment 10S: Area 2 Tc=10.0 min CN=94 Runoff=3.47 cfs 0.206 af Runoff Area=2,747 sf 9.25% Impervious Runoff Depth>4.35"Subcatchment 11S: Area 3 Tc=5.0 min CN=76 Runoff=0.52 cfs 0.023 af Inflow=5.72 cfs 0.355 afPond 10P: Offsite to North Primary=5.72 cfs 0.355 af Peak Elev=907.49' Storage=315 cf Inflow=3.47 cfs 0.206 afPond 11P: Raingarden B2 Outflow=3.36 cfs 0.202 af Peak Elev=910.25' Storage=1,693 cf Inflow=2.95 cfs 0.169 afPond 12P: Raingarden B1 Primary=0.84 cfs 0.114 af Secondary=1.59 cfs 0.040 af Outflow=2.43 cfs 0.154 af Inflow=5.72 cfs 0.355 afPond 13P: Offsite to Frontage Primary=5.72 cfs 0.355 af Inflow=0.52 cfs 0.023 afPond 14P: Offsite to West Primary=0.52 cfs 0.023 af Total Runoff Area = 0.794 ac Runoff Volume = 0.398 af Average Runoff Depth = 6.01" 30.66% Pervious = 0.243 ac 69.34% Impervious = 0.550 ac MSE 24-hr 3 100-year Rainfall=7.30"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 29HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Summary for Subcatchment 9S: Area 1 Runoff = 2.95 cfs @ 12.17 hrs, Volume= 0.169 af, Depth> 5.92" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs MSE 24-hr 3 100-year Rainfall=7.30" Area (sf) CN Description 9,701 98 Paved parking, HSG C 5,233 74 >75% Grass cover, Good, HSG C 14,934 90 Weighted Average 5,233 35.04% Pervious Area 9,701 64.96% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Subcatchment 9S: Area 1 Runoff Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)3 2 1 0 MSE 24-hr 3 100-year Rainfall=7.30" Runoff Area=14,934 sf Runoff Volume=0.169 af Runoff Depth>5.92" Tc=10.0 min CN=90 2.95 cfs MSE 24-hr 3 100-year Rainfall=7.30"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 30HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Summary for Subcatchment 10S: Area 2 Runoff = 3.47 cfs @ 12.17 hrs, Volume= 0.206 af, Depth> 6.36" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs MSE 24-hr 3 100-year Rainfall=7.30" Area (sf) CN Description 14,017 98 Paved parking, HSG C 2,873 74 >75% Grass cover, Good, HSG C 16,890 94 Weighted Average 2,873 17.01% Pervious Area 14,017 82.99% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Subcatchment 10S: Area 2 Runoff Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)3 2 1 0 MSE 24-hr 3 100-year Rainfall=7.30" Runoff Area=16,890 sf Runoff Volume=0.206 af Runoff Depth>6.36" Tc=10.0 min CN=94 3.47 cfs MSE 24-hr 3 100-year Rainfall=7.30"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 31HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Summary for Subcatchment 11S: Area 3 [49] Hint: Tc<2dt may require smaller dt Runoff = 0.52 cfs @ 12.12 hrs, Volume= 0.023 af, Depth> 4.35" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs MSE 24-hr 3 100-year Rainfall=7.30" Area (sf) CN Description 254 98 Paved parking, HSG C 2,493 74 >75% Grass cover, Good, HSG C 2,747 76 Weighted Average 2,493 90.75% Pervious Area 254 9.25% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment 11S: Area 3 Runoff Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 MSE 24-hr 3 100-year Rainfall=7.30" Runoff Area=2,747 sf Runoff Volume=0.023 af Runoff Depth>4.35" Tc=5.0 min CN=76 0.52 cfs MSE 24-hr 3 100-year Rainfall=7.30"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 32HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Summary for Pond 10P: Offsite to North [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 0.731 ac, 74.53% Impervious, Inflow Depth > 5.84" for 100-year event Inflow = 5.72 cfs @ 12.21 hrs, Volume= 0.355 af Primary = 5.72 cfs @ 12.21 hrs, Volume= 0.355 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Pond 10P: Offsite to North Inflow Primary Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)6 5 4 3 2 1 0 Inflow Area=0.731 ac 5.72 cfs 5.72 cfs MSE 24-hr 3 100-year Rainfall=7.30"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 33HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Summary for Pond 11P: Raingarden B2 [82] Warning: Early inflow requires earlier time span Inflow Area = 0.388 ac, 82.99% Impervious, Inflow Depth > 6.36" for 100-year event Inflow = 3.47 cfs @ 12.17 hrs, Volume= 0.206 af Outflow = 3.36 cfs @ 12.19 hrs, Volume= 0.202 af, Atten= 3%, Lag= 1.5 min Primary = 3.36 cfs @ 12.19 hrs, Volume= 0.202 af Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Peak Elev= 907.49' @ 12.19 hrs Surf.Area= 345 sf Storage= 315 cf Plug-Flow detention time= 15.5 min calculated for 0.201 af (98% of inflow) Center-of-Mass det. time= 7.6 min ( 753.6 - 746.0 ) Volume Invert Avail.Storage Storage Description #1 906.00' 393 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 906.00 95 0 0 907.00 247 171 171 907.70 388 222 393 Device Routing Invert Outlet Devices #1 Primary 904.50'12.0" Round Culvert L= 10.0' CPP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 904.50' / 904.40' S= 0.0100 '/' Cc= 0.900 n= 0.012 Concrete pipe, finished, Flow Area= 0.79 sf #2 Device 1 906.00'0.500 in/hr Exfiltration over Surface area #3 Device 1 907.00'2.0" x 18.0" Horiz. Orifice/Grate X 4 rows C= 0.600 in 24.0" Grate (32% open area) Limited to weir flow at low heads Primary OutFlow Max=3.33 cfs @ 12.19 hrs HW=907.48' (Free Discharge) 1=Culvert (Passes 3.33 cfs of 4.70 cfs potential flow) 2=Exfiltration (Exfiltration Controls 0.00 cfs) 3=Orifice/Grate (Orifice Controls 3.33 cfs @ 3.33 fps) MSE 24-hr 3 100-year Rainfall=7.30"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 34HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Pond 11P: Raingarden B2 Inflow Primary Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)3 2 1 0 Inflow Area=0.388 ac Peak Elev=907.49' Storage=315 cf 3.47 cfs 3.36 cfs MSE 24-hr 3 100-year Rainfall=7.30"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 35HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Summary for Pond 12P: Raingarden B1 Inflow Area = 0.343 ac, 64.96% Impervious, Inflow Depth > 5.92" for 100-year event Inflow = 2.95 cfs @ 12.17 hrs, Volume= 0.169 af Outflow = 2.43 cfs @ 12.24 hrs, Volume= 0.154 af, Atten= 18%, Lag= 4.0 min Primary = 0.84 cfs @ 12.24 hrs, Volume= 0.114 af Secondary = 1.59 cfs @ 12.24 hrs, Volume= 0.040 af Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Peak Elev= 910.25' @ 12.24 hrs Surf.Area= 1,708 sf Storage= 1,693 cf Plug-Flow detention time= 52.0 min calculated for 0.153 af (91% of inflow) Center-of-Mass det. time= 24.2 min ( 779.2 - 755.0 ) Volume Invert Avail.Storage Storage Description #1 908.50' 2,141 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 908.50 231 0 0 909.50 1,066 649 649 910.50 1,918 1,492 2,141 Device Routing Invert Outlet Devices #1 Primary 906.50'12.0" Round Culvert L= 213.0' CPP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 906.50' / 906.00' S= 0.0023 '/' Cc= 0.900 n= 0.012 Concrete pipe, finished, Flow Area= 0.79 sf #2 Device 1 908.50'0.500 in/hr Exfiltration over Surface area #3 Secondary 909.80'2.0' long x 2.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 Coef. (English) 2.54 2.61 2.61 2.60 2.66 2.70 2.77 2.89 2.88 2.85 3.07 3.20 3.32 #4 Device 1 909.50'6.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads Primary OutFlow Max=0.84 cfs @ 12.24 hrs HW=910.25' (Free Discharge) 1=Culvert (Passes 0.84 cfs of 4.12 cfs potential flow) 2=Exfiltration (Exfiltration Controls 0.02 cfs) 4=Orifice/Grate (Orifice Controls 0.82 cfs @ 4.16 fps) Secondary OutFlow Max=1.56 cfs @ 12.24 hrs HW=910.25' (Free Discharge) 3=Broad-Crested Rectangular Weir (Weir Controls 1.56 cfs @ 1.75 fps) MSE 24-hr 3 100-year Rainfall=7.30"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 36HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Pond 12P: Raingarden B1 Inflow Outflow Primary Secondary Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)3 2 1 0 Inflow Area=0.343 ac Peak Elev=910.25' Storage=1,693 cf 2.95 cfs 2.43 cfs 0.84 cfs 1.59 cfs MSE 24-hr 3 100-year Rainfall=7.30"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 37HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Summary for Pond 13P: Offsite to Frontage [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 0.731 ac, 74.53% Impervious, Inflow Depth > 5.84" for 100-year event Inflow = 5.72 cfs @ 12.21 hrs, Volume= 0.355 af Primary = 5.72 cfs @ 12.21 hrs, Volume= 0.355 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Pond 13P: Offsite to Frontage Inflow Primary Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)6 5 4 3 2 1 0 Inflow Area=0.731 ac 5.72 cfs 5.72 cfs MSE 24-hr 3 100-year Rainfall=7.30"Tire Pros Printed 8/16/2022Prepared by Stevens Engineers Page 38HydroCAD® 10.00-20 s/n 02721 © 2017 HydroCAD Software Solutions LLC Summary for Pond 14P: Offsite to West [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 0.063 ac, 9.25% Impervious, Inflow Depth > 4.35" for 100-year event Inflow = 0.52 cfs @ 12.12 hrs, Volume= 0.023 af Primary = 0.52 cfs @ 12.12 hrs, Volume= 0.023 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Pond 14P: Offsite to West Inflow Primary Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Inflow Area=0.063 ac 0.52 cfs 0.52 cfs Appendix G P8 Modeling P8 Urban Catchment Model, Version 3.5Run Date 08/16/22Case p8 Tire Pros try 2.p8cFirstDate 01/01/71 Precip(in) 27.7Title 2 filtration basinsLastDate 12/31/71 Rain(in) 24.42PrecFile msp_4989.pcpEvents 64 Snow(in) 3.32PartFile nurp50.p8pTotalHrs 7656 TotalYrs 0.87Case Title2 filtration basinsCase Data Filep8 Tire Pros try 2.p8cPathC:\P8_UserFiles\Case Notes:Storm Data Filemsp_4989.pcpParticle Filenurp50.p8pAir Temp File File msp_4889.temTime Steps Per Hour4Minimum Inter-Event Time (hrs) 10Maximum Continuity Error % 2Rainfall Breakpoint (inches) 0.8Precipitation Scale Factor1Air Temp Offset (deg-F)0Loops Thru Storm File1Simulation DatesStart1/1/1970Keep1/1/1971Stop12/31/1971Max Snowfall Temperature (deg-f) 32.0SnowMelt Temperature (deg-f) 32.0Snowmelt Coef (in/degF-Day) 0.06Soil Freeze Temp (deg-F)32.0Snowmelt Abstraction Factor 1.00Evapo-Trans. Calibration Factor 1.00Growing Season Start Month 5Growing Season End Month 105-Day Antecedent Rainfall + Runoff (inches)CN Antecedent Moisture Condition AMC-II AMC-IIIGrowing Season1.40 2.10NonGrowing Season0.50 1.10Watershed DataWatershed NameArea 1 Area 2 Area 3Runoff to DeviceIron Enhanced Basin Iron Enhanced Basin 2 Untreated StormwaterInfiltration to Device Watershed Area0.34 0.39 0.06SCS Curve Number (Pervious) 74 74 74Scale Factor for Pervious Runoff Load 1 1 1Indirectly Connected Imperv Fraction 0 0 0UnSwept Impervious Fraction 0.65 0.83 0.09UnSwept Depression Storage (inches) 0.02 0.02 0.02UnSwept Imperv. Runoff Coefficient 1 1 1UnSwept Scale Factor for Particle Loads 1 1 1Swept Impervious Fraction0 0 0Swept Depression Storage (inches) 0.02 0.02 0.02Swept Imperv. Runoff Coefficient 1 1 1Swept Scale Factor for Particle Loads 1 1 1Sweeping Frequency0 0.5 0.5Sweeping Efficiency1 1 1Sweeping Start Date (MMDD) 101 101 101Sweeping Stop Date (MMDD) 1231 1231 1231Device DataDevice NameTreated Stormwater Iron Enhanced Basin Untreated StormwaterIron Enhanced Basin 2Device TypePIPE INF_BASIN PIPE INF_BASINInfiltration OutletTreated Stormwater Treated StormwaterNormal OutletSpillway OutletUntreated Stormwater Untreated StormwaterParticle Removal Scale Factor11Bottom Elevation (ft)908.5906Bottom Area (acres)0.0050.002Permanent Pool Area (acres)Permanent Pool Volume (ac-ft)Perm Pool Infilt Rate (in/hr)Flood Pool Area (acres)0.030.006Flood Pool Volume (ac-ft)0.0230.04Flood Pool Infilt Rate (in/hr)0.50.5Infilt Basin Void Fraction (%)100100Detention Pond Outlet ParametersOutlet TypeOutlet Orifice Diameter (in)Orifice Discharge CoefOutlet Weir Length (ft)Weir Discharge CoefPerforated Riser Height (ft)Number of Holes in RiserHoles DiameterFlood Pool Drain Time (hrs)Swale ParametersLength of Flow Path (ft) Slope of Flow Path %Bottom Width (ft)Side Slope (ft-v/ft-h)Maximum Depth of Flow (ft)Mannings n ConstantHydraulic ModelPipe, Splitter, Aquifer ParameterHydraulic Res. Time (hrs)00Particle DataParticle File nurp50.p8pParticle Class P0% P10% P30% P50% P80%Filtration Efficiency (%) 90 100 100 100 100Settling Velocity (ft/hr) 0 0.03 0.3 1.5 15First Order Decay Rate (1/day) 0 0 0 0 02nd Order Decay (1/day-ppm) 0 0 0 0 0Impervious Runoff Conc (ppm) 1 0 0 0 0Pervious Runoff Conc (ppm) 1 100 100 100 200Pervious Conc Exponent 0 1 1 1 1Accum. Rate (lbs-ac-day) 0 1.75 1.75 1.75 3.5Particle Removal Rate (1/day) 0 0.25 0.25 0.25 0.25Washoff Coefficient 0 20 20 20 20Washoff Exponent 0 2 2 2 2Sweeper Efficiency 0 0 0 5 15Water Quality Component DataComponent Name TSS TP TKN CU PB ZN HCWater Quality Criteria (ppm)Level 1 5 0.025 2 2 0.02 5 0.1Level 2 10 0.05 1 0.0048 0.014 0.0362 0.5Level 3 20 0.1 0.5 0.02 0.15 0.38 1Content Scale Factor 1 1 1 1 1 1 1Particle Composition (mg/kg)P0%0 99000 600000 13600 2000 64000 250000P10% 1000000 3850 15000 340 180 1600 22500P30% 1000000 3850 15000 340 180 1600 22500P50% 1000000 3850 15000 340 180 1600 22500P80% 1000000 0 0 340 180 0 22500 P8 Urban Catchment Model, Version 3.5Run Date 08/16/22Case p8 Tire Pros try 2.p8cFirstDate 01/01/71 Precip(in) 27.7Title 2 filtration basinsLastDate 12/31/71 Rain(in) 24.42PrecFile msp_4989.pcpEvents 64 Snow(in) 3.32PartFile nurp50.p8pTotalHrs 7656 TotalYrs 0.87HydraulicsSedimentation rates assume bulk density of 1 ton per cubic yard of wet sediment.Variable Units Iron Enhanced Basin Iron Enhanced Basin 2 Treated Stormwater Untreated StormwaterTotal Inflow ac-ft 0.52 0.74 1.17 0.11Total Outflow ac-ft 0.52 0.74 1.17 0.11Mean Inflow cfs 0.00 0.00 0.00 0.00Mean Outflow cfs 0.00 0.00 0.00 0.00Max Inflow cfs 0.31 0.44 0.02 0.74Max Outflow cfs 0.29 0.43 0.02 0.74Min Elev ft 908.51 906.01 0.00 0.00Max Elev ft 909.81 916.00 0.00 0.00Max Velocity ft/sec 0.00 0.00 0.00 0.00Wet Period % 10.61 58.33 0.00 0.00WtrBal Error ac-ft 0.00 0.00 0.00 0.00WtrBal Error% % 0.00 0.00 0.00 0.00Max Area acres 0.03 0.01 0.00 0.00Mean Hyd Load in/day 0.65 4.64 0.00 0.00Max Hyd Load in/hr 10.24 71.99 0.00 0.00Sed Rate Mass tons/ac-yr 3.04 21.68 0.00 0.00Sed Rate Vol yd3/yr 0.09 0.13 0.00 0.00Sed Rate Depth in/yr 0.02 0.16 0.00 0.00Max Volume ac-ft 0.02 0.04 0.00 0.00Direct Watershed acres 0.34 0.39 0.00 0.06Unit Runoff inches/yr 21.04 26.08 0.00 5.38Total 1.28 ac-ft runoff Appendix H Phosphorus Calculation https://stormwater.pca.state.mn.us/index.php?title=Calculating_credits_for_iron_enhanced_sand_filter