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Pleasant View Pointe - SWMP - 7-3-2025Stormwater Management Hydrologic and Hydraulic Study Pleasant View Pointe Chanhassen, MN City of Chanhassen Minnehaha Creek Watershed District July 3, 2025 Pleasant View Pointe Development Hydrologic and Hydraulic Study 7/2/2025 Alliant Engineering, Inc. Page 1 of 10 221-0203 Introduction Included in this report are the materials necessary to review the stormwater management plan for the proposed “Pleasant View Pointe” project in Chanhassen, Minnesota. The following information is included: • Study Narrative • Stormwater Wetland Zone Classifications • Drainage Area Maps • Rate Control HydroCAD Calculation Reports • Water Quality Calculations: o Proposed MIDS estimating pond phosphorous and TSS removal efficiency. • Storm Sewer Calculations • Low Point Modeling • Geotechnical Soil Borings Background This study was conducted to analyze the stormwater treatment requirements for a proposed residential subdivision in Chanhassen, MN and within Minnehaha Creek Watershed District (MCWD) boundary. The study will show that the proposed stormwater management system will nullify the effects of the increased impervious cover resulting from the new development. The study assumes the following two scenarios: • Existing conditions – Single Residence occupying property. • Proposed conditions – Development of the residential project. o City of Chanhassen urban improvements of Pleasant View Road and installation of storm sewer. Project Area Total Site Area based on boundary (acres) 14.560 Total Proposed SWMP Area including Offsite Area (acres) 24.134 Existing Site Impervious (acres) 0.443 Post Construction Site Impervious (acres) 4.466 Proposed (future) Pleasant View Road Impervious 1.099 Proposed Peaceful Lane Road 0.231 Total Volume Control Impervious Area (acres) * 5.795 Impervious Area Routed to North BMP (acres) 4.893 Impervious Area Routed to West BMP (acres) 0.683 Impervious Area Routed to South BMP (acres) 0.219 *Total volume control area impervious is the proposed impervious created from the subdivision and additionally, impervious for proposed future Pleasant View Road. Pleasant View Pointe Development Hydrologic and Hydraulic Study 7/2/2025 Alliant Engineering, Inc. Page 2 of 10 221-0203 Runoff Rate Control All rate control calculations have been performed using the method via HydroCAD software. Three events were modeled including: the 2-year, 10-year and 100-year, MSE Type 3 24-hour storm events, AMC 2, with ATLAS-14 precipitation amounts of 2.87”, 4.28”, and 7.38”, used respectively. All existing and proposed curve numbers are based on estimations of land cover and soil type from attached geotechnical report. Based on the soil borings from Geotechnical Analysis, an aggregate hydrologic soil group of “D” was assumed throughout the site. Times of concentrations were typically estimated and modeled using direct entry and lag method. Existing Conditions The project site is currently 5 parcels, with 1 single family residence, driveway, and outbuildings. The development site is located South of Christmas Lake. A portion of the site does fall withing the 1,000’ shoreland district for Christmas Lake. The site consists of wooded uplands and grassed areas, existing stormwater pond, historic remnant wetland, and incidental wetland. The project does contain bluff as defined by the City of Chanhassen code. The property has variable slopes from flat to more than 3:1. Roughly ½ of the site drains via overland or storm sewer to the existing pond. The existing pond was modified with the development of the Troendle Addition. A majority of the Troendle Addition does drain to the existing pond via storm sewer. The existing pond/wetland outlets via 8” pipe to the west to existing preserve wetland as defined by MCWD. A small portion of the site NE drains to existing Pleasant View Road and continues East. A small portion drains east offsite. A portion drains south through existing residential to Lake Lucy Road. A portion drains overland to the west down to a ditch that swales and drains to a low point culvert. The culvert then outlets west towards the existing preserve wetland. Wetland 1 was determined to be incidental and will be graded and removed. The historic remnant wetland will remain in place except a small portion of 1268 sf will be filled. The wetland has been permitted to be impacted completely and will be mitigated offsite. In effort to preserve and satisfy the City of Chanhassen code, the remnant wetland is being incorporated into the proposed BMP. • E-1 – Onsite area that drains overland to the existing onsite remnant wetland/pond. • E-2 – Onsite area that drains overland to existing Troendle Additon storm sewer proceeding to the existing remnant wetland/onsite pond. • E-3 – Onsite area that drains overland to the South through existing residential, proceeding to Lake Lucy Road storm sewer. • E-4 - Onsite area that drains West overland to a ditch that swales and drains to a low point culvert. The culvert outlets and drains to an existing offsite preserve wetland. • E-5 – Onsite area that drains overland offsite to existing Pleasant View Road and continues East • E-6 – Onsite area that drains East to existing residential area. • E-7 – Onsite area that drains overland to existing Troendle Additon storm sewer proceeding to the existing onsite remnant wetland/pond. • E-8 – Onsite pervious area that drains overland West to existing offsite preserve wetland. • OFF-1 – Offsite Troendle Addition residential single family homes and roadways that drain via storm sewer to the onsite existing remnant wetland/pond. • OFF-2 – Offsite residential that drains overland to the existing remnant wetland/pond. • OFF-3 – Offsite residential and Pleasant View Road that drains via roadway and ditches to the existing onsite remnant wetland/pond. • OFF-4 – Offsite existing residential and Peaceful Lane roadway that drains to the existing offsite preserve wetland to the West. • OFF-5 – Offsite pervious area drains West overland to a ditch that swales and drains to a low point culvert. The culvert outlets and drains to an existing offsite preserve wetland. • OFF-6 – Offsite area that drains onto the site overland and proceeds South to Lake Lucy Road storm sewer. Pleasant View Pointe Development Hydrologic and Hydraulic Study 7/2/2025 Alliant Engineering, Inc. Page 3 of 10 221-0203 To compare peak discharge rates for the existing and proposed conditions, flows were analyzed compositely. Refer to the existing conditions drainage map and HydroCAD report for additional information and detailed calculations. Site composite existing runoff rate as calculated by HydroCAD are listed in the table below: In the current condition where Pleasant View Road is not constructed the NE discharge point remains. In that condition the sub catchment E5 is not captured by storm sewer and flows East in city of Chanhassen ROW and is not captured. Below is the rate in the condition where that runoff is not captured. This only looks at onsite proposed areas. Current Existing condition w/out Pleasant View Rd. Reconstructed. Proposed Conditions The proposed development area is made up of 5 existing parcels totaling in 13.60 acres. The parcels are split in the middle by existing public ROW intended to connect Nez Pierce Drive and Peaceful Lane. The ROW splitting the parcels will be vacated (included in new site area) and new road ROW will be provided. The site is bound by existing residential properties to the east and south. The property is then bound on the west and north by a two roads and public ROW. A portion of the existing ROW along the old Redman Lane has a resolution to be vacated from 1987 (see survey and plan). This ROW will be vacated and given back to abutting landowner and is included in site area. The total site area included to be platted with new ROW is 14.56 AC. Rachel Development is proposing 20 new residential single-family homes. Drainage maps provided show delineations based on full development. The site is capturing and treating all new created imperious from the site. The city will be re-constructing Pleasant View Road in the future. The proposed stormwater management plan has assumed treatment for an assumed city street section 31’ back to back with a 10’ wide trail as well as a forecasted larger drainage area that will be captured in the future by storm sewer and piped back to the new north BMP. The expanded drainage area was estimated by assuming 4’ minimum starting catch basin build, with 0.5% slope to the NWL of the north BMP at 994.0. The below screen shot shows blue hatched area, the new area added to the proposed conditions of the modeling and is included. Event South (cfs) West (cfs) Northeast (cfs) East (cfs) Northwest (cfs) 2 year (2.87” 24hr) 4.80 8.54 4.49 0.59 2.28 10 year (4.28” 24hr) 9.32 13.92 8.04 1.16 3.91 100 year (7.33” 24hr) 20.13 24.06 16.45 2.53 7.66 Event Northeast (cfs) 2 year (2.87” 24hr) 1.01 10 year (4.28” 24hr) 1.99 100 year (7.33” 24hr) 4.35 Pleasant View Pointe Development Hydrologic and Hydraulic Study 7/2/2025 Alliant Engineering, Inc. Page 4 of 10 221-0203 The stormwater management plan for the proposed conditions will meet the guidelines required by the City of Chanhassen and Minnehaha Creek Watershed District (MCWD) for stormwater rate and volume control. The following criterion was used in designing the stormwater management system: • Post-development peak runoff rate from the site for the 2, 10 and 100-year 24-hour MSE 3 24-hour storm events (Hershfield, DM. 1961 rainfall frequency.) must not be greater than existing condition rates in accordance with the City and. To remain conservative, Alliant used the (Atlas 14) rainfall data for modeling purposes. • Development may not increase the peak runoff rate from the site, in aggregate for the design rainfall events. • Newly constructed stormwater BMPs shall provide water quality volume treatment in accordance with 90 percent TSS removal and 60 percent TP removal. • Provide volume control equivalent to 1.0” of runoff from all proposed impervious surface, in accordance with MCWD volume control requirements. If filtration is used as BMP volume provided must be twice the required volume reduction. • Freeboard, the lowest building opening must be at minimum 1’ above the emergency over flow elevation. Building adjacent to stormwater basin shall be 3’ above the 100 year high water level (HWL). • Impact to downstream waterbodies receiving runoff shall be in accordance with MCWD. The proposed residential development will consist of 20 single family homes and associated roadways as shown in the plan set. The project will include one stormwater wetland with a filtration bench and one filtration basin to provide rate and volume control, for treatment of the stormwater runoff. The filtration basin to the west will have pre-treatment provided by overland drainage. Stormwater runoff from the new roadways, and all front yards and several rear yards will be collected by storm sewer and piped to the proposed north stormwater treatment BMP. Some of the rear yards will run directly into the BMP. 5 rear yards will run west to the filtration basin. The proposed stormwater that was being collected for Troendle Additon is still being collected via stormsewer and routed to the proposed stormwater wetland/filtration basin. The proposed basin will be capturing, the OFF-4 that previously drained West toward the existing pond. Most of the area that previously drained south to Lake Lucy Road is being captured and will run to the proposed north BMP via storm sewer. The following HydroCAD sub catchments were used in the proposed conditions model: • S-1 - Onsite area that drains overland and unconnected to the proposed BMP • S-2 - Onsite area that drains to storm sewer and then to the proposed BMP. • S-3 – Onsite pervious area that drains overland to the South through existing residential, proceeding to Lake Lucy Road storm sewer. • S-4 – Onsite area that drains overland to the West to a proposed filtration basin. • S-5 - Onsite area that drains overland offsite to Exiting Pleasant View Road and will be captured with the City’s Pleasant View Road re-construction storm sewer. • S-6 - Onsite pervious area that drains East to existing residential area. • S-7 – Onsite pervious area that drains overland west to existing wetland. • S-8 – Onsite pervious area that drains overland west to existing wetland. • S-9 – Onsite disconnected impervious and pervious area that drains overland to Filtration Trench • OFF-1 – Offsite existing Troendle Addition residential single family homes and roadways that drain via storm sewer to the onsite proposed BMP. • OFF-2 – Offsite residential that drains overland to the proposed BMP. Pleasant View Pointe Development Hydrologic and Hydraulic Study 7/2/2025 Alliant Engineering, Inc. Page 5 of 10 221-0203 • OFF-3 – Offsite residential and Proposed Pleasant View Road that drains via roadway and ditches and future storm sewer to a low point proposed catch basin and rip rap forebay to and proposed BMP. The impervious area included here includes the future city road and trail. • OFF-4 – Offsite existing residential and Peaceful Lane roadway that is now captured via stormsewer and drains to the proposed BMP. • OFF-5 – Offsite pervious area drains overland to the proposed West filtration basin. • OFF-6 – Offsite area that drains overland to onsite filtration trench. This area previously drained to the south to Lake Lucy Road storm sewer. • OFF – 7 – offsite area that drains overland to the north BMP. This area newly captured by the site due to proposed grading. Previously drained onto the site then south and east with S6 area. • OFF – 8 – offsite area that can be captured by newly constructed Pleasant View Road construction and storm sewer. Area previously drained to the east away from project. • OFF – 9 – offsite area that can be captured by newly constructed Pleasant View Road construction and storm sewer. Area previously drained to the west away from project. Most of the runoff from the site’s developed area will be routed to the proposed BMP stormwater wetland with a filtration bench and underdrain or a filtration basin to the west. The filtration bench will provide the required filtration volume required by the city and watershed. The BMPs have an OCS (Outlet Control Structure) that will be used to provide a controlled discharge rate to the existing west wetland offsite. The outlet for the proposed pond will be installed in the same location and have the same elevation as the existing pond outlet. The proposed stormwater management plan decreases the composite peak discharge rate for all stormwater events to below existing conditions. The proposed stormwater plan also decreases to 3 discharge points and will ultimately remove drainage to the NW and NE discharge points once Pleasant View Rd is reconstructed. Refer to the proposed conditions drainage map and HydroCAD report sheets for additional information. Site composite proposed runoff rate as calculated by HydroCAD are listed in the table below: In the current condition where Pleasant View Road is not constructed the NE discharge point remains. In that condition the sub catchment S5 is not captured by storm sewer and flows East and is not captured. Below is the rate in the condition where that runoff is not captured. This only looks at onsite proposed areas. Interim condition is very temporary. City anticipated construction of Pleasant View Road is year 2026. Current Proposed condition w/out Pleasant View Rd. Reconstructed. Event South (cfs) West (cfs) Northeast (cfs) East (cfs) Northwest (cfs) 2 year (2.87” 24hr) 3.07 8.34 0 0.25 0 10 year (4.28” 24hr) 5.93 12.02 0 0.50 0 100 year (7.33” 24hr) 12.43 14.83 0 1.07 0 Event Northeast (cfs) 2 year (2.87” 24hr) 1.40 10 year (4.28” 24hr) 2.34 100 year (7.33” 24hr) 4.52 Pleasant View Pointe Development Hydrologic and Hydraulic Study 7/2/2025 Alliant Engineering, Inc. Page 6 of 10 221-0203 Stormwater Volume Control Required Volume The project is required to provide volume control in accordance with the MCWD criteria. Volume control equivalent to 1” over the proposed impervious surface is required. MCWD requirements for volume control can be found in adopted rules 4-29-2025. See section 3.a.1. Next see Table 1, and appendix a for the criteria. The volume control shall be taken care of by infiltration unless deemed in-feasible. The site soils are primarily made up of Hydraulic Soil Group D soils (sandy lean clay (CL), clayey sands (SC). Per watershed stormwater management rule 3.b.5, infiltration shall not be used. The volume control requirement is being met through filtration. The total new proposed impervious surface from proposed roadways, driveways, buildings, is 194,547 sf (4.446 AC). The new proposed site impervious is the actual new road impervious, and the maximum amount of impervious per lot. Conservatively, the maximum allowed impervious per lot was used to determine the required treatment volume, not what is shown by sample footprint in the plans. Required treatment volume for the site is equal to 16,212 cubic feet. MCWD requires filtration bmp to provided twice the required volume to be provided. The required volume control for the proposed subdivision is 32,425 cubic feet. See appendix a of the watershed district stormwater rules for filtration volume treatment requirements. Additional Required Volume The city will be re-constructing Pleasant View Road and will be installing storm sewer to capture the re- constructed road. An analysis has been completed to determine the extents to what can be captured by the storm sewer. The new road area has been assumed to be 31’ back to back road with 10’ trail. Impervious to be treated for Pleasant View Road section is 47,867 sf (1.099 AC). Also, Peaceful Lane will be re- constructed in coordination with the City of Chanhassen. This adds, 10,072 sf (0.231 AC), impervious road. The required treatment volume for Peaceful Lane and future Pleasant View Road is 4,828 CF x 2 (MCWD) 9,656.44 CF. The stormwater wetland / filtration basin has been oversized to treat the city’s stormwater for their proposed project of Pleasant View Road. This shall satisfy the watershed and city’s requirement for volume control of treatment for 1” over the proposed impervious surface treated at 2x. and can be used as part of the city’s construction project. Total Required Water Quality Volume 42,081 CF Proposed Volume The total treatment volume provided is equal to 54,692 CF. On top of the required treatment for the proposed development site and the City of Chanhassen’s Pleasant View Road re-construct, The site provides 12,388 CF of volume control over the requirements. Stormwater Wetland / Filtration Shelf There is 47,696 CF provided by the north Stormwater Wetland. The filtration volume is set by the OCS orifice within weir wall set at 995.0 resulting in a 1.0’ storage depth will filter through a 11,928 sf media mix b section to an underdrain system. Details of the OCS and wetland/filtration shelf can be found in the proposed development plans. West Filtration Basin There is 5,289 CF provided treatment volume by the West Filtration Basin. The filtration volume is set by the OCS notch in wier wall set at 996.5 resulting in a 1.5’ storage depth that will filter through 2,670 sf media mix b section to an underdrain system. Details of the OCS and basin can be found in the proposed development plans. South Filtration Trench There is 1,707 CF provided treatment volume by the South Filtration Trench. The filtration volume is set by the overflow berm at 1020.0 located along the south edge of the proposed trench. The filtration depth is 1.0’ Pleasant View Pointe Development Hydrologic and Hydraulic Study 7/2/2025 Alliant Engineering, Inc. Page 7 of 10 221-0203 that will filter through the 600 sf trench/and filter to an underdrain system. Details of the trench can be found in the proposed development plans. Proposed Underdrains The underdrains proposed in the project will be installed per city of Chanhassen standard details and the MN stormwater manual. The quantity of underdrain is determined by the Carver County watershed design criteria of 1 lf of draintile per 50 cf of ponded filtration volume. See the development plans for further details on the proposed filtration section and underdrain designs. Stormwater Wetland / Filtration Shelf Minimum recommended draintile is equal to 47,696 CF /1LF 50 cf = 954 LF. West Filtration Basin Minimum recommended draintile is equal to 5,289 CF /1LF 50 cf = 106 LF. South Filtration Trench Minimum recommended draintile is equal to 1,707 CF /1LF 50 cf = 34 LF. Filtration Systems Draw Down Calculation The filtration basin will draw down within 48 hours per MPCA guidelines. The assumed infiltration rate of media mix b and sand has been assumed at 1.0 in/hr. The infiltration rate is a reasonably conservative estimate and will likely be the filtration rate over time. Per the MPCA an infiltration rate of 1.63in/hr can be used for sand. Basin Filtration Volume (cf) Filtration Depth Filtration Surface Area (sf) Effective Filtration Depth (in)* Draw Down Time Stormwater Wetland /Filtration 47,696 1.0’ 11,928 47.98 48 hr West Filtration Basin 5,289 1.5’ 2,670 24.22 25 hr South Filtration Trench 1,707 1.0’ 600 34.14 35 hr * Effective filtration depth is used for estimating draw down timeframe. 𝑴𝒂𝒘𝒉𝒍𝒕𝒍 𝑨𝒍𝒍𝒍𝒘𝒂𝒂𝒍𝒆 𝑫𝒓𝒂𝒘 𝑫𝒍𝒘𝒍 𝒂𝒍𝒍𝒍𝒕𝒕𝒂𝒕𝒉𝒍𝒍. 𝟒𝟖 𝒉𝒍 ÷ 𝟎.𝟎 𝒉𝒍 𝒉𝒓 =𝟒𝟖 𝒉𝒓 Stormwater Quality The stormwater management system must have an 90% TSS and 60% Phosphorus removal efficiency from proposed conditions. MIDS Calculator was used to calculate TSS and TP removal efficiencies. See the MIDS Results for reference. The onsite area totaling and proposed Peaceful Lane and Pleasant View Road. 14.56 AC + 1.33 = 15.89 AC. When analyzing the removal efficiency for the stormwater wetland/filtration system it has been estimated that 25% of inflow will bypass treatment by the stormwater wetland (per MN BMP manual this translates to a 40% undersized BMP. This bypass has been conservatively assumed to factor in the approximate flow that will route to the wetland filter with forebay pretreatment. This assumption remains consistent for all 3 scenarios considered. Pleasant View Pointe Development Hydrologic and Hydraulic Study 7/2/2025 Alliant Engineering, Inc. Page 8 of 10 221-0203 TSS and TP removal efficiencies as calculated by MIDS Calculator (Site and Pleasant View Imp.: Total Proposed TSS Removal Efficiency Proposed P Removal Efficiency Site Removal 93% 66% Troendle Addition Although not required to provide upgrade water quality treatment for this drainage area, a MIDS model was created to analyze what the treatment will be provided for the offsite Troendle Addition. This scenario adds the offsite catchment OFF-1 area and impervious to the required design area and impervious. The MIDS result shows that the system will treat above the required 90% TSS and 60% TP removal efficiencies. TSS and TP removal efficiencies as calculated by MIDS Calculator (Site and Pleasant View Imp.: Total Proposed TSS Removal Efficiency Proposed P Removal Efficiency Site Removal 93% 64% Entire SWM Site Area Although not required to provide upgrade water quality treatment for all offsite contributing area and impervious surfaces, a MIDS model was created to analyze what the treatment will be provided for that scenario. This scenario analyzes the entire watershed 24.137AC. The MIDS result shows that the system is treating above the required 90% TSS and 60% TP removal efficiencies. TSS and TP removal efficiencies as calculated by MIDS Calculator (Site and Pleasant View Imp.: Total Proposed TSS Removal Efficiency Proposed P Removal Efficiency Site Removal 93% 63% Impact on Downgradient Waterbodies Per MCWD wetland inventory, there are 3 wetlands that receive runoff from the site. Existing wetland to the west is a preserve wetland per the MCWD. Per wetland rules the permitted bounce for storm event is existing for a preserve wetland. To determine that the site meets the requirements, lidar contours were used to model the existing wetland. The normal water level was surveyed at an elevation of 974.1. An 18” standpipe was observed and recorded to be the outlet for the preserve wetland. The model only takes into consideration the project site drainage area. See below the results from the existing and proposed conditions for the bounce. Existing Wetland to SE of catchment S6 is a preserve wetland per MCWD. The total area and flow to the East was reduced in all storm events; therefore, does not create a bounce on the downstream wetland. No new impervious is created that flows to the east from catchment S6. See below results of existing and proposed volumes. Event Existing HWL Proposed HWL 2 year (2.87” 24hr) 974.35 974.27 10 year (4.28” 24hr) 974.48 974.38 100 year (7.33” 24hr) 974.85 974.84 Event Existing Volume (AC-FT) Proposed Volume (AC-FT) 2 year (2.87” 24hr) 0.024 0.010 10 year (4.28” 24hr) 0.047 0.019 100 year (7.33” 24hr) 0.107 0.043 Pleasant View Pointe Development Hydrologic and Hydraulic Study 7/2/2025 Alliant Engineering, Inc. Page 9 of 10 221-0203 Existing Wetland to South of catchment S3 and S9 is a manage 1 wetland per MCWD. The total area and flow to the South initially drains to city storm sewer in Lake Lucy Road but will eventually drain to the wetland. The flow offsite south was reduced in all storm events; therefore, it will not create a negative bounce on the downstream wetland. A filtration trench has been installed to migitate the new impervious in catchment S9. See below results of existing and proposed volumes. Low Point Analysis (per MCWD) Analysis estimates the 100 year storm high water level for two rear yard catch basins, CB 203 and CB 210 as requested by MCWD. Also refer to HydroCAD report in appendix. CB 203 – Rim Elevation = 1008.90, EOF = 1010.05, 100-yr HWL = 1009.23 CB210 – Rim Elevation = 1015.40, EOF = 1017.70, 100-yr HWL = 1015.99 Conclusion Alliant Engineering believes that the proposed design is acceptable for all parties involved. The peak discharge rates for the 2-year, 10-year and 100-year 24-hour storm events will be decreased in aggregate from existing rates for the proposed conditions. Sufficient runoff volume control has been provided by the stormwater management system to mitigate the proposed impervious surface additions. The proposed stormwater management system meets the TSS and TP removal efficiency requirements. Finally, the proposed grading and SWPPP plans will utilize Best Management Practices whenever possible to provide adequate erosion control measures to contain sediment during construction. Please call 612-767-9330 with any questions or comments regarding stormwater issues for the Pleasant View Pointe subdivision. Tyler Stricherz, PE Mark Rausch, PE Alliant Engineering, Inc. CC: File 4000320 Event Existing Volume (AC-FT) Proposed Volume (AC-FT) 2 year (2.87” 24hr) 0.227 0.178 10 year (4.28” 24hr) 0.440 0.332 100 year (7.33” 24hr) 0.978 0.715 Pleasant View Pointe Development Hydrologic and Hydraulic Study 7/2/2025 Alliant Engineering, Inc. Page 10 of 10 221-0203 APPENDIX - Stormwater Wetland Zone Classifications – 6-4-25 - Rate Control Supporting Documents ▪ Drainage Delineation Maps 6-4-25 • Existing Conditions • Proposed Conditions ▪ Rate Control HydroCAD Reports • Existing Conditions 6-4-25 • Proposed Conditions - Water Quality Supporting Calculations • Proposed MIDS Calculator - Storm Sewer Calculations - Low point modeling analysis 6-4-25 - Spread Calc Analysis - RPBCWD – Existing Home Analysis - Geotechnical Analysis - Watershed Stormwater Guidelines PLEASANT VIEW RD 3 7 56 BLOCK 1 STORMWATER WETLAND/FILTRATION NWL:994.0 100 YEAR HWL:999.86 PEACEFUL LANEFile Location: X:\4000320-00\001\30 Exhibits\Stormwater Wetland Area Map.dwg Plotted By: Tyler Stricherz on April 18, 2025 at 11:59:05 AM PLEASANT VIEW POINTE - CONSTRUCTED WETLAND - ZONE CLASSIFICATIONS File Location: X:\4000320-00\001\30 Exhibits\Stormwater Wetland Area Map.dwg Plotted By: Tyler Stricherz on April 18, 2025 at 11:59:05 AM File Location: X:\4000320-00\001\40 Design\45 Stormwater\HYDRO-X-1.dwg Plotted By: Mark Rausch on June 4, 2025 at 8:11:48 PMKnow what's below.Call before you dig.RDial 811FOR REV IEW ONLYPRELIM INARYNOT FOR CONSTRUCT ION0SCALE IN FEET3570140NWSEPRELIMINARY PLAT CIT SUBMITTAL FINAL PLAT - CITY SUBMITTAL 4-18-2025 12-19-2024 11CHANHASSEN, MN PLEASANT VIEW POINTE EXISTING DRAINAGE MAP www.alliant-inc.comPROJECT TEAM DATAQA/QC CHECKDateByCERTIFICATIONDateLicense no.DATE DESCRIPTION Project No.:Drafted By:Designed By:Sheetof TAS I hereby certify that this plan, specification, or reportwas prepared by me or under my direct supervisionand that I am a duly LicensedProfessional Engineer under the laws of theState of Minnesota. 11LEGEND E1 E1 E2 E2 E3 E3 E4 E4 E5 E5 E6 E6 E7 E7 E8 E8 OFF-1 OFF-1 OFF-2 OFF-2 OFF-3 OFF-3 OFF-4 OFF-4 OFF-5 OFF-5 OFF-6 OFF-6 OFF-7 OFF-7 OFF-8 OFF-8 OFF-9 OFF-9 1P EXISTING POND 2P West Ditch 10P West Exisitng Wetland 3L SOUTH 5L NORTHEAST 6L EAST 7L TOTAL 8L Existing to NORTHWEST Routing Diagram for EDRN Prepared by Alliant Engineering, Inc, Printed 6/4/2025 HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Subcat Reach Pond Link EDRN EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 2HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Area Listing (all nodes) Area (acres) CN Description (subcatchment-numbers) 12.403 80 >75% Grass cover, Good, HSG D (E1, E2, E3, E7, OFF-4, OFF-6, OFF-7, OFF-8, OFF-9) 0.040 98 Impervious, HSG D (OFF-6) 3.086 98 Paved parking, HSG D (E7, OFF-1, OFF-3, OFF-4, OFF-8, OFF-9) 0.523 98 Unconnected roofs, HSG D (E1, E2, E4, OFF-2, OFF-7) 0.555 98 Water Surface, HSG D (E1) 0.206 82 Woods/grass comb., Fair, HSG D (OFF-5) 7.066 79 Woods/grass comb., Good, HSG D (E4, E5, E6, OFF-1, OFF-2, OFF-3) 0.255 86 Woods/grass comb., Poor, HSG D (E8) EDRN EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 3HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Soil Listing (all nodes) Area (acres) Soil Group Subcatchment Numbers 0.000 HSG A 0.000 HSG B 0.000 HSG C 24.133 HSG D E1, E2, E3, E4, E5, E6, E7, E8, OFF-1, OFF-2, OFF-3, OFF-4, OFF-5, OFF-6, OFF-7, OFF-8, OFF-9 0.000 Other EDRN MSE 24-hr 3 2-Year Rainfall=2.87"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 4HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Time span=0.00-600.00 hrs, dt=0.01 hrs, 60001 points Runoff by SCS TR-20 method, UH=SCS, Weighted-Q Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method Runoff Area=274,415 sf 9.50% Impervious Runoff Depth=1.29"Subcatchment E1: E1 Flow Length=498' Slope=0.0723 '/' Tc=6.3 min CN=WQ Runoff=14.59 cfs 0.680 af Runoff Area=2.401 ac 4.33% Impervious Runoff Depth=1.22"Subcatchment E2: E2 Flow Length=680' Slope=0.0323 '/' Tc=13.6 min UI Adjusted CN=WQ Runoff=3.88 cfs 0.244 af Runoff Area=1.887 ac 0.00% Impervious Runoff Depth=1.15"Subcatchment E3: E3 Flow Length=327' Slope=0.0550 '/' Tc=5.5 min CN=80 Runoff=4.18 cfs 0.181 af Runoff Area=122,681 sf 9.85% Impervious Runoff Depth=1.25"Subcatchment E4: E4 Flow Length=550' Tc=9.4 min UI Adjusted CN=WQ Runoff=5.42 cfs 0.293 af Runoff Area=0.458 ac 0.00% Impervious Runoff Depth=1.09"Subcatchment E5: E5 Flow Length=198' Slope=0.0404 '/' Tc=4.5 min CN=79 Runoff=1.01 cfs 0.042 af Runoff Area=0.260 ac 0.00% Impervious Runoff Depth=1.09"Subcatchment E6: E6 Flow Length=136' Slope=0.0330 '/' Tc=3.7 min CN=79 Runoff=0.59 cfs 0.024 af Runoff Area=0.183 ac 10.38% Impervious Runoff Depth=1.31"Subcatchment E7: E7 Flow Length=155' Slope=0.0160 '/' Tc=6.3 min CN=WQ Runoff=0.43 cfs 0.020 af Runoff Area=11,092 sf 0.00% Impervious Runoff Depth=1.55"Subcatchment E8: E8 Tc=1.0 min CN=86 Runoff=0.86 cfs 0.033 af Runoff Area=3.643 ac 43.65% Impervious Runoff Depth=1.77"Subcatchment OFF-1: OFF-1 Flow Length=564' Slope=0.0323 '/' Tc=9.8 min CN=WQ Runoff=9.27 cfs 0.537 af Runoff Area=0.406 ac 22.66% Impervious Runoff Depth=1.44"Subcatchment OFF-2: OFF-2 Flow Length=270' Slope=0.0741 '/' Tc=3.7 min UI Adjusted CN=WQ Runoff=1.13 cfs 0.049 af Runoff Area=86,082 sf 27.02% Impervious Runoff Depth=1.51"Subcatchment OFF-3: OFF-3 Flow Length=489' Slope=0.0613 '/' Tc=6.4 min CN=WQ Runoff=5.10 cfs 0.249 af Runoff Area=23,335 sf 43.88% Impervious Runoff Depth=1.81"Subcatchment OFF-4: OFF-4 Flow Length=337' Slope=0.0297 '/' Tc=5.9 min CN=WQ Runoff=1.65 cfs 0.081 af Runoff Area=8,976 sf 0.00% Impervious Runoff Depth=1.28"Subcatchment OFF-5: OFF-5 Flow Length=349' Tc=5.2 min CN=82 Runoff=0.51 cfs 0.022 af Runoff Area=18,405 sf 9.38% Impervious Runoff Depth=1.29"Subcatchment OFF-6: OFF-6 Flow Length=564' Slope=0.0323 '/' Tc=11.5 min CN=WQ Runoff=0.78 cfs 0.046 af Runoff Area=2,943 sf 9.17% Impervious Runoff Depth=1.29"Subcatchment OFF-7: OFF-7 Flow Length=429' Tc=7.1 min UI Adjusted CN=WQ Runoff=0.15 cfs 0.007 af Runoff Area=70,469 sf 31.01% Impervious Runoff Depth=1.61"Subcatchment OFF-8: OFF-8 Tc=10.0 min CN=WQ Runoff=3.80 cfs 0.218 af EDRN MSE 24-hr 3 2-Year Rainfall=2.87"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 5HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Runoff Area=30,431 sf 29.47% Impervious Runoff Depth=1.59"Subcatchment OFF-9: OFF-9 Tc=0.0 min CN=WQ Runoff=2.28 cfs 0.093 af Peak Elev=994.35' Storage=50,141 cf Inflow=32.79 cfs 1.785 afPond 1P: EXISTING POND 8.0" Round Culvert n=0.010 L=324.0' S=0.0080 '/' Outflow=1.53 cfs 1.783 af Peak Elev=995.91' Storage=27 cf Inflow=5.80 cfs 0.314 afPond 2P: West Ditch Primary=5.80 cfs 0.314 af Secondary=0.00 cfs 0.000 af Outflow=5.80 cfs 0.314 af Peak Elev=974.35' Storage=19,101 cf Inflow=8.54 cfs 2.211 afPond 10P: West Exisitng Wetland Outflow=1.92 cfs 2.210 af Inflow=4.80 cfs 0.227 afLink 3L: SOUTH Primary=4.80 cfs 0.227 af Inflow=4.49 cfs 0.259 afLink 5L: NORTHEAST Primary=4.49 cfs 0.259 af Inflow=0.59 cfs 0.024 afLink 6L: EAST Primary=0.59 cfs 0.024 af Inflow=10.98 cfs 2.813 afLink 7L: TOTAL Primary=10.98 cfs 2.813 af Inflow=2.28 cfs 0.093 afLink 8L: Existing to NORTHWEST Primary=2.28 cfs 0.093 af EDRN MSE 24-hr 3 2-Year Rainfall=2.87"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 6HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment E1: E1 Runoff = 14.59 cfs @ 12.14 hrs, Volume= 0.680 af, Depth= 1.29" Routed to Pond 1P : EXISTING POND Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 2-Year Rainfall=2.87" Area (sf) CN Description 1,904 98 Unconnected roofs, HSG D 24,173 98 Water Surface, HSG D 248,338 80 >75% Grass cover, Good, HSG D 274,415 Weighted Average 248,338 90.50% Pervious Area 26,077 9.50% Impervious Area 1,904 7.30% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.3 498 0.0723 1.31 Lag/CN Method, Subcatchment E1: E1 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 MSE 24-hr 3 2-Year Rainfall=2.87" Runoff Area=274,415 sf Runoff Volume=0.680 af Runoff Depth=1.29" Flow Length=498' Slope=0.0723 '/' Tc=6.3 min CN=WQ 14.59 cfs EDRN MSE 24-hr 3 2-Year Rainfall=2.87"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 7HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment E2: E2 Runoff = 3.88 cfs @ 12.22 hrs, Volume= 0.244 af, Depth= 1.22" Routed to Pond 1P : EXISTING POND Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 2-Year Rainfall=2.87" Area (ac) CN Adj Description 0.104 98 98 Unconnected roofs, HSG D 2.297 80 80 >75% Grass cover, Good, HSG D 2.401 Weighted Average 2.297 95.67% Pervious Area 0.104 4.33% Impervious Area 0.104 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 12.6 680 0.0323 0.90 Lag/CN Method, OVERLAND - SWALE 1.0 Direct Entry, STORM SEWER 13.6 680 Total Subcatchment E2: E2 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)4 3 2 1 0 MSE 24-hr 3 2-Year Rainfall=2.87" Runoff Area=2.401 ac Runoff Volume=0.244 af Runoff Depth=1.22" Flow Length=680' Slope=0.0323 '/' Tc=13.6 min UI Adjusted CN=WQ 3.88 cfs EDRN MSE 24-hr 3 2-Year Rainfall=2.87"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 8HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment E3: E3 Runoff = 4.18 cfs @ 12.13 hrs, Volume= 0.181 af, Depth= 1.15" Routed to Link 3L : SOUTH Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 2-Year Rainfall=2.87" Area (ac) CN Description 1.887 80 >75% Grass cover, Good, HSG D 1.887 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.5 327 0.0550 0.98 Lag/CN Method, OVERLAND Subcatchment E3: E3 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)4 3 2 1 0 MSE 24-hr 3 2-Year Rainfall=2.87" Runoff Area=1.887 ac Runoff Volume=0.181 af Runoff Depth=1.15" Flow Length=327' Slope=0.0550 '/' Tc=5.5 min CN=80 4.18 cfs EDRN MSE 24-hr 3 2-Year Rainfall=2.87"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 9HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment E4: E4 Runoff = 5.42 cfs @ 12.17 hrs, Volume= 0.293 af, Depth= 1.25" Routed to Pond 2P : West Ditch Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 2-Year Rainfall=2.87" Area (sf) CN Adj Description 12,084 98 98 Unconnected roofs, HSG D 110,597 79 79 Woods/grass comb., Good, HSG D 122,681 Weighted Average 110,597 90.15% Pervious Area 12,084 9.85% Impervious Area 12,084 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.8 385 0.0620 1.11 Lag/CN Method, OVERLAND 1.1 100 0.2000 1.53 Lag/CN Method, 2.5 65 0.0198 0.44 Lag/CN Method, 9.4 550 Total Subcatchment E4: E4 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)6 5 4 3 2 1 0 MSE 24-hr 3 2-Year Rainfall=2.87" Runoff Area=122,681 sf Runoff Volume=0.293 af Runoff Depth=1.25" Flow Length=550' Tc=9.4 min UI Adjusted CN=WQ 5.42 cfs EDRN MSE 24-hr 3 2-Year Rainfall=2.87"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 10HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment E5: E5 Runoff = 1.01 cfs @ 12.12 hrs, Volume= 0.042 af, Depth= 1.09" Routed to Link 5L : NORTHEAST Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 2-Year Rainfall=2.87" Area (ac) CN Description 0.458 79 Woods/grass comb., Good, HSG D 0.458 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 4.5 198 0.0404 0.74 Lag/CN Method, OVERLAND Subcatchment E5: E5 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)1 0 MSE 24-hr 3 2-Year Rainfall=2.87" Runoff Area=0.458 ac Runoff Volume=0.042 af Runoff Depth=1.09" Flow Length=198' Slope=0.0404 '/' Tc=4.5 min CN=79 1.01 cfs EDRN MSE 24-hr 3 2-Year Rainfall=2.87"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 11HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment E6: E6 Runoff = 0.59 cfs @ 12.12 hrs, Volume= 0.024 af, Depth= 1.09" Routed to Link 6L : EAST Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 2-Year Rainfall=2.87" Area (ac) CN Description 0.260 79 Woods/grass comb., Good, HSG D 0.260 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 3.7 136 0.0330 0.62 Lag/CN Method, OVERLAND Subcatchment E6: E6 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)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 2-Year Rainfall=2.87" Runoff Area=0.260 ac Runoff Volume=0.024 af Runoff Depth=1.09" Flow Length=136' Slope=0.0330 '/' Tc=3.7 min CN=79 0.59 cfs EDRN MSE 24-hr 3 2-Year Rainfall=2.87"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 12HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment E7: E7 Runoff = 0.43 cfs @ 12.14 hrs, Volume= 0.020 af, Depth= 1.31" Routed to Pond 1P : EXISTING POND Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 2-Year Rainfall=2.87" Area (ac) CN Description 0.019 98 Paved parking, HSG D 0.164 80 >75% Grass cover, Good, HSG D 0.183 Weighted Average 0.164 89.62% Pervious Area 0.019 10.38% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.3 155 0.0160 0.49 Lag/CN Method, OVERLAND 1.0 Direct Entry, STORM SEWER 6.3 155 Total Subcatchment E7: E7 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)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=2.87" Runoff Area=0.183 ac Runoff Volume=0.020 af Runoff Depth=1.31" Flow Length=155' Slope=0.0160 '/' Tc=6.3 min CN=WQ 0.43 cfs EDRN MSE 24-hr 3 2-Year Rainfall=2.87"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 13HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment E8: E8 Runoff = 0.86 cfs @ 12.10 hrs, Volume= 0.033 af, Depth= 1.55" Routed to Pond 10P : West Exisitng Wetland Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 2-Year Rainfall=2.87" Area (sf) CN Description 11,092 86 Woods/grass comb., Poor, HSG D 11,092 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 1.0 Direct Entry, Subcatchment E8: E8 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (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 2-Year Rainfall=2.87" Runoff Area=11,092 sf Runoff Volume=0.033 af Runoff Depth=1.55" Tc=1.0 min CN=86 0.86 cfs EDRN MSE 24-hr 3 2-Year Rainfall=2.87"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 14HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment OFF-1: OFF-1 Runoff = 9.27 cfs @ 12.17 hrs, Volume= 0.537 af, Depth= 1.77" Routed to Pond 1P : EXISTING POND Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 2-Year Rainfall=2.87" Area (ac) CN Description 1.590 98 Paved parking, HSG D 2.053 79 Woods/grass comb., Good, HSG D 3.643 Weighted Average 2.053 56.35% Pervious Area 1.590 43.65% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 8.8 564 0.0323 1.07 Lag/CN Method, BACK YARD SWALE 1.0 Direct Entry, Storm Sewer 9.8 564 Total Subcatchment OFF-1: OFF-1 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)10 9 8 7 6 5 4 3 2 1 0 MSE 24-hr 3 2-Year Rainfall=2.87" Runoff Area=3.643 ac Runoff Volume=0.537 af Runoff Depth=1.77" Flow Length=564' Slope=0.0323 '/' Tc=9.8 min CN=WQ 9.27 cfs EDRN MSE 24-hr 3 2-Year Rainfall=2.87"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 15HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment OFF-2: OFF-2 Runoff = 1.13 cfs @ 12.11 hrs, Volume= 0.049 af, Depth= 1.44" Routed to Pond 1P : EXISTING POND Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 2-Year Rainfall=2.87" Area (ac) CN Adj Description 0.092 98 98 Unconnected roofs, HSG D 0.314 79 79 Woods/grass comb., Good, HSG D 0.406 Weighted Average 0.314 77.34% Pervious Area 0.092 22.66% Impervious Area 0.092 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 3.7 270 0.0741 1.21 Lag/CN Method, Subcatchment OFF-2: OFF-2 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)1 0 MSE 24-hr 3 2-Year Rainfall=2.87" Runoff Area=0.406 ac Runoff Volume=0.049 af Runoff Depth=1.44" Flow Length=270' Slope=0.0741 '/' Tc=3.7 min UI Adjusted CN=WQ 1.13 cfs EDRN MSE 24-hr 3 2-Year Rainfall=2.87"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 16HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment OFF-3: OFF-3 Runoff = 5.10 cfs @ 12.14 hrs, Volume= 0.249 af, Depth= 1.51" Routed to Pond 1P : EXISTING POND Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 2-Year Rainfall=2.87" Area (sf) CN Description 23,261 98 Paved parking, HSG D 62,821 79 Woods/grass comb., Good, HSG D 86,082 Weighted Average 62,821 72.98% Pervious Area 23,261 27.02% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.4 489 0.0613 1.28 Lag/CN Method, Subcatchment OFF-3: OFF-3 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)5 4 3 2 1 0 MSE 24-hr 3 2-Year Rainfall=2.87" Runoff Area=86,082 sf Runoff Volume=0.249 af Runoff Depth=1.51" Flow Length=489' Slope=0.0613 '/' Tc=6.4 min CN=WQ 5.10 cfs EDRN MSE 24-hr 3 2-Year Rainfall=2.87"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 17HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment OFF-4: OFF-4 Runoff = 1.65 cfs @ 12.13 hrs, Volume= 0.081 af, Depth= 1.81" Routed to Pond 10P : West Exisitng Wetland Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 2-Year Rainfall=2.87" Area (sf) CN Description 10,240 98 Paved parking, HSG D 13,095 80 >75% Grass cover, Good, HSG D 23,335 Weighted Average 13,095 56.12% Pervious Area 10,240 43.88% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.9 337 0.0297 0.96 Lag/CN Method, Subcatchment OFF-4: OFF-4 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)1 0 MSE 24-hr 3 2-Year Rainfall=2.87" Runoff Area=23,335 sf Runoff Volume=0.081 af Runoff Depth=1.81" Flow Length=337' Slope=0.0297 '/' Tc=5.9 min CN=WQ 1.65 cfs EDRN MSE 24-hr 3 2-Year Rainfall=2.87"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 18HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment OFF-5: OFF-5 Runoff = 0.51 cfs @ 12.13 hrs, Volume= 0.022 af, Depth= 1.28" Routed to Pond 2P : West Ditch Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 2-Year Rainfall=2.87" Area (sf) CN Description 8,976 82 Woods/grass comb., Fair, HSG D 8,976 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 1.6 194 0.2474 2.00 Lag/CN Method, 3.6 155 0.0354 0.72 Lag/CN Method, 5.2 349 Total Subcatchment OFF-5: OFF-5 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (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 2-Year Rainfall=2.87" Runoff Area=8,976 sf Runoff Volume=0.022 af Runoff Depth=1.28" Flow Length=349' Tc=5.2 min CN=82 0.51 cfs EDRN MSE 24-hr 3 2-Year Rainfall=2.87"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 19HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment OFF-6: OFF-6 Runoff = 0.78 cfs @ 12.20 hrs, Volume= 0.046 af, Depth= 1.29" Routed to Link 3L : SOUTH Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 2-Year Rainfall=2.87" Area (sf) CN Description * 1,727 98 Impervious, HSG D 16,678 80 >75% Grass cover, Good, HSG D 18,405 Weighted Average 16,678 90.62% Pervious Area 1,727 9.38% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.5 564 0.0323 0.90 Lag/CN Method, BACK YARD SWALE 1.0 Direct Entry, Storm Sewer 11.5 564 Total Subcatchment OFF-6: OFF-6 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)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 2-Year Rainfall=2.87" Runoff Area=18,405 sf Runoff Volume=0.046 af Runoff Depth=1.29" Flow Length=564' Slope=0.0323 '/' Tc=11.5 min CN=WQ 0.78 cfs EDRN MSE 24-hr 3 2-Year Rainfall=2.87"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 20HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment OFF-7: OFF-7 Runoff = 0.15 cfs @ 12.15 hrs, Volume= 0.007 af, Depth= 1.29" Routed to Pond 1P : EXISTING POND Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 2-Year Rainfall=2.87" Area (sf) CN Adj Description 2,673 80 80 >75% Grass cover, Good, HSG D 270 98 98 Unconnected roofs, HSG D 2,943 Weighted Average 2,673 90.83% Pervious Area 270 9.17% Impervious Area 270 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 1.1 83 0.1445 1.29 Lag/CN Method, 6.0 346 0.0448 0.96 Lag/CN Method, 7.1 429 Total Subcatchment OFF-7: OFF-7 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)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 2-Year Rainfall=2.87" Runoff Area=2,943 sf Runoff Volume=0.007 af Runoff Depth=1.29" Flow Length=429' Tc=7.1 min UI Adjusted CN=WQ 0.15 cfs EDRN MSE 24-hr 3 2-Year Rainfall=2.87"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 21HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment OFF-8: OFF-8 Runoff = 3.80 cfs @ 12.18 hrs, Volume= 0.218 af, Depth= 1.61" Routed to Link 5L : NORTHEAST Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 2-Year Rainfall=2.87" Area (sf) CN Description 21,849 98 Paved parking, HSG D 48,620 80 >75% Grass cover, Good, HSG D 70,469 Weighted Average 48,620 68.99% Pervious Area 21,849 31.01% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, storm sewer Subcatchment OFF-8: OFF-8 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)4 3 2 1 0 MSE 24-hr 3 2-Year Rainfall=2.87" Runoff Area=70,469 sf Runoff Volume=0.218 af Runoff Depth=1.61" Tc=10.0 min CN=WQ 3.80 cfs EDRN MSE 24-hr 3 2-Year Rainfall=2.87"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 22HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment OFF-9: OFF-9 Runoff = 2.28 cfs @ 12.09 hrs, Volume= 0.093 af, Depth= 1.59" Routed to Link 8L : Existing to NORTHWEST Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 2-Year Rainfall=2.87" Area (sf) CN Description 8,967 98 Paved parking, HSG D 21,464 80 >75% Grass cover, Good, HSG D 30,431 Weighted Average 21,464 70.53% Pervious Area 8,967 29.47% Impervious Area Subcatchment OFF-9: OFF-9 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)2 1 0 MSE 24-hr 3 2-Year Rainfall=2.87" Runoff Area=30,431 sf Runoff Volume=0.093 af Runoff Depth=1.59" Tc=0.0 min CN=WQ 2.28 cfs EDRN MSE 24-hr 3 2-Year Rainfall=2.87"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 23HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Pond 1P: EXISTING POND Inflow Area = 14.976 ac, 19.66% Impervious, Inflow Depth = 1.43" for 2-Year event Inflow = 32.79 cfs @ 12.15 hrs, Volume= 1.785 af Outflow = 1.53 cfs @ 13.62 hrs, Volume= 1.783 af, Atten= 95%, Lag= 88.5 min Primary = 1.53 cfs @ 13.62 hrs, Volume= 1.783 af Routed to Pond 10P : West Exisitng Wetland Routing by Dyn-Stor-Ind method, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs Peak Elev= 994.35' @ 13.62 hrs Surf.Area= 36,088 sf Storage= 50,141 cf Plug-Flow detention time= 573.6 min calculated for 1.783 af (100% of inflow) Center-of-Mass det. time= 573.3 min ( 1,370.9 - 797.6 ) Volume Invert Avail.Storage Storage Description #1 992.61' 277,554 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 992.61 24,173 0 0 994.00 31,142 38,444 38,444 996.00 59,569 90,711 129,155 998.00 88,830 148,399 277,554 Device Routing Invert Outlet Devices #1 Primary 992.61'8.0" Round Culvert L= 324.0' CPP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 992.61' / 990.02' S= 0.0080 '/' Cc= 0.900 n= 0.010 PVC, smooth interior, Flow Area= 0.35 sf Primary OutFlow Max=1.53 cfs @ 13.62 hrs HW=994.35' TW=974.35' (Dynamic Tailwater) 1=Culvert (Barrel Controls 1.53 cfs @ 4.39 fps) EDRN MSE 24-hr 3 2-Year Rainfall=2.87"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 24HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Pond 1P: EXISTING POND Inflow Primary Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)36 34 32 30 28 26 24 22 20 18 16 14 12 10 8 6 4 2 0 Inflow Area=14.976 ac Peak Elev=994.35' Storage=50,141 cf 8.0" Round Culvert n=0.010 L=324.0' S=0.0080 '/' 32.79 cfs 1.53 cfs EDRN MSE 24-hr 3 2-Year Rainfall=2.87"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 25HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Pond 2P: West Ditch Inflow Area = 3.022 ac, 9.18% Impervious, Inflow Depth = 1.25" for 2-Year event Inflow = 5.80 cfs @ 12.17 hrs, Volume= 0.314 af Outflow = 5.80 cfs @ 12.17 hrs, Volume= 0.314 af, Atten= 0%, Lag= 0.2 min Primary = 5.80 cfs @ 12.17 hrs, Volume= 0.314 af Routed to Pond 10P : West Exisitng Wetland Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Routed to Pond 10P : West Exisitng Wetland Routing by Dyn-Stor-Ind method, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs Peak Elev= 995.91' @ 12.17 hrs Surf.Area= 54 sf Storage= 27 cf Plug-Flow detention time= (not calculated: outflow precedes inflow) Center-of-Mass det. time= 0.0 min ( 810.3 - 810.2 ) Volume Invert Avail.Storage Storage Description #1 995.00' 5,727 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 995.00 5 0 0 996.00 59 32 32 997.00 825 442 474 998.00 2,243 1,534 2,008 998.60 4,093 1,901 3,909 999.00 5,000 1,819 5,727 Device Routing Invert Outlet Devices #1 Primary 994.57'18.0" Round CMP_Round 18" L= 57.1' CMP, mitered to conform to fill, Ke= 0.700 Inlet / Outlet Invert= 994.57' / 989.52' S= 0.0884 '/' Cc= 0.900 n= 0.025 Corrugated metal, Flow Area= 1.77 sf #2 Secondary 998.59'20.0' long x 16.0' breadth Existing Berm Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 Coef. (English) 2.68 2.70 2.70 2.64 2.63 2.64 2.64 2.63 Primary OutFlow Max=5.80 cfs @ 12.17 hrs HW=995.91' TW=974.23' (Dynamic Tailwater) 1=CMP_Round 18" (Inlet Controls 5.80 cfs @ 3.48 fps) Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=995.00' TW=974.10' (Dynamic Tailwater) 2=Existing Berm ( Controls 0.00 cfs) EDRN MSE 24-hr 3 2-Year Rainfall=2.87"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 26HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Pond 2P: West Ditch Inflow Outflow Primary Secondary Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)6 5 4 3 2 1 0 Inflow Area=3.022 ac Peak Elev=995.91' Storage=27 cf 5.80 cfs 5.80 cfs 5.80 cfs 0.00 cfs EDRN MSE 24-hr 3 2-Year Rainfall=2.87"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 27HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Pond 10P: West Exisitng Wetland Inflow Area = 18.789 ac, 18.40% Impervious, Inflow Depth = 1.41" for 2-Year event Inflow = 8.54 cfs @ 12.16 hrs, Volume= 2.211 af Outflow = 1.92 cfs @ 13.61 hrs, Volume= 2.210 af, Atten= 78%, Lag= 87.2 min Primary = 1.92 cfs @ 13.61 hrs, Volume= 2.210 af Routed to Link 7L : TOTAL Routing by Dyn-Stor-Ind method, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs Starting Elev= 974.10' Surf.Area= 54,326 sf Storage= 5,411 cf Peak Elev= 974.35' @ 13.61 hrs Surf.Area= 55,407 sf Storage= 19,101 cf (13,690 cf above start) Plug-Flow detention time= 371.9 min calculated for 2.086 af (94% of inflow) Center-of-Mass det. time= 168.8 min ( 1,429.8 - 1,261.0 ) Volume Invert Avail.Storage Storage Description #1 974.00' 487,616 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 974.00 53,893 0 0 975.00 58,226 56,060 56,060 976.00 62,886 60,556 116,616 977.00 67,093 64,990 181,605 978.00 71,582 69,338 250,943 979.00 76,083 73,833 324,775 980.00 81,311 78,697 403,472 981.00 86,977 84,144 487,616 Device Routing Invert Outlet Devices #1 Primary 974.10'18.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads Primary OutFlow Max=1.92 cfs @ 13.61 hrs HW=974.35' TW=0.00' (Dynamic Tailwater) 1=Orifice/Grate (Weir Controls 1.92 cfs @ 1.63 fps) EDRN MSE 24-hr 3 2-Year Rainfall=2.87"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 28HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Pond 10P: West Exisitng Wetland Inflow Primary Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)9 8 7 6 5 4 3 2 1 0 Inflow Area=18.789 ac Peak Elev=974.35' Storage=19,101 cf 8.54 cfs 1.92 cfs EDRN MSE 24-hr 3 2-Year Rainfall=2.87"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 29HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Link 3L: SOUTH Inflow Area = 2.310 ac, 1.72% Impervious, Inflow Depth = 1.18" for 2-Year event Inflow = 4.80 cfs @ 12.14 hrs, Volume= 0.227 af Primary = 4.80 cfs @ 12.14 hrs, Volume= 0.227 af, Atten= 0%, Lag= 0.0 min Routed to Link 7L : TOTAL Primary outflow = Inflow, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs Link 3L: SOUTH Inflow Primary Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)5 4 3 2 1 0 Inflow Area=2.310 ac 4.80 cfs 4.80 cfs EDRN MSE 24-hr 3 2-Year Rainfall=2.87"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 30HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Link 5L: NORTHEAST Inflow Area = 2.076 ac, 24.16% Impervious, Inflow Depth = 1.50" for 2-Year event Inflow = 4.49 cfs @ 12.16 hrs, Volume= 0.259 af Primary = 4.49 cfs @ 12.16 hrs, Volume= 0.259 af, Atten= 0%, Lag= 0.0 min Routed to Link 7L : TOTAL Primary outflow = Inflow, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs Link 5L: NORTHEAST Inflow Primary Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)5 4 3 2 1 0 Inflow Area=2.076 ac 4.49 cfs 4.49 cfs EDRN MSE 24-hr 3 2-Year Rainfall=2.87"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 31HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Link 6L: EAST Inflow Area = 0.260 ac, 0.00% Impervious, Inflow Depth = 1.09" for 2-Year event Inflow = 0.59 cfs @ 12.12 hrs, Volume= 0.024 af Primary = 0.59 cfs @ 12.12 hrs, Volume= 0.024 af, Atten= 0%, Lag= 0.0 min Routed to Link 7L : TOTAL Primary outflow = Inflow, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs Link 6L: EAST Inflow Primary Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)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=0.260 ac 0.59 cfs 0.59 cfs EDRN MSE 24-hr 3 2-Year Rainfall=2.87"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 32HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Link 7L: TOTAL Inflow Area = 24.133 ac, 17.42% Impervious, Inflow Depth = 1.40" for 2-Year event Inflow = 10.98 cfs @ 12.14 hrs, Volume= 2.813 af Primary = 10.98 cfs @ 12.14 hrs, Volume= 2.813 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs Link 7L: TOTAL Inflow Primary Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)12 11 10 9 8 7 6 5 4 3 2 1 0 Inflow Area=24.133 ac 10.98 cfs 10.98 cfs EDRN MSE 24-hr 3 2-Year Rainfall=2.87"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 33HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Link 8L: Existing to NORTHWEST Inflow Area = 0.699 ac, 29.47% Impervious, Inflow Depth = 1.59" for 2-Year event Inflow = 2.28 cfs @ 12.09 hrs, Volume= 0.093 af Primary = 2.28 cfs @ 12.09 hrs, Volume= 0.093 af, Atten= 0%, Lag= 0.0 min Routed to Link 7L : TOTAL Primary outflow = Inflow, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs Link 8L: Existing to NORTHWEST Inflow Primary Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)2 1 0 Inflow Area=0.699 ac 2.28 cfs 2.28 cfs EDRN MSE 24-hr 3 10-Year Rainfall=4.26"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 34HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Time span=0.00-600.00 hrs, dt=0.01 hrs, 60001 points Runoff by SCS TR-20 method, UH=SCS, Weighted-Q Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method Runoff Area=274,415 sf 9.50% Impervious Runoff Depth=2.43"Subcatchment E1: E1 Flow Length=498' Slope=0.0723 '/' Tc=6.3 min CN=WQ Runoff=27.35 cfs 1.274 af Runoff Area=2.401 ac 4.33% Impervious Runoff Depth=2.33"Subcatchment E2: E2 Flow Length=680' Slope=0.0323 '/' Tc=13.6 min UI Adjusted CN=WQ Runoff=7.54 cfs 0.467 af Runoff Area=1.887 ac 0.00% Impervious Runoff Depth=2.26"Subcatchment E3: E3 Flow Length=327' Slope=0.0550 '/' Tc=5.5 min CN=80 Runoff=8.12 cfs 0.355 af Runoff Area=122,681 sf 9.85% Impervious Runoff Depth=2.36"Subcatchment E4: E4 Flow Length=550' Tc=9.4 min UI Adjusted CN=WQ Runoff=10.37 cfs 0.554 af Runoff Area=0.458 ac 0.00% Impervious Runoff Depth=2.18"Subcatchment E5: E5 Flow Length=198' Slope=0.0404 '/' Tc=4.5 min CN=79 Runoff=1.99 cfs 0.083 af Runoff Area=0.260 ac 0.00% Impervious Runoff Depth=2.18"Subcatchment E6: E6 Flow Length=136' Slope=0.0330 '/' Tc=3.7 min CN=79 Runoff=1.16 cfs 0.047 af Runoff Area=0.183 ac 10.38% Impervious Runoff Depth=2.44"Subcatchment E7: E7 Flow Length=155' Slope=0.0160 '/' Tc=6.3 min CN=WQ Runoff=0.80 cfs 0.037 af Runoff Area=11,092 sf 0.00% Impervious Runoff Depth=2.78"Subcatchment E8: E8 Tc=1.0 min CN=86 Runoff=1.48 cfs 0.059 af Runoff Area=3.643 ac 43.65% Impervious Runoff Depth=2.98"Subcatchment OFF-1: OFF-1 Flow Length=564' Slope=0.0323 '/' Tc=9.8 min CN=WQ Runoff=15.68 cfs 0.906 af Runoff Area=0.406 ac 22.66% Impervious Runoff Depth=2.60"Subcatchment OFF-2: OFF-2 Flow Length=270' Slope=0.0741 '/' Tc=3.7 min UI Adjusted CN=WQ Runoff=2.03 cfs 0.088 af Runoff Area=86,082 sf 27.02% Impervious Runoff Depth=2.68"Subcatchment OFF-3: OFF-3 Flow Length=489' Slope=0.0613 '/' Tc=6.4 min CN=WQ Runoff=9.06 cfs 0.441 af Runoff Area=23,335 sf 43.88% Impervious Runoff Depth=3.03"Subcatchment OFF-4: OFF-4 Flow Length=337' Slope=0.0297 '/' Tc=5.9 min CN=WQ Runoff=2.76 cfs 0.135 af Runoff Area=8,976 sf 0.00% Impervious Runoff Depth=2.43"Subcatchment OFF-5: OFF-5 Flow Length=349' Tc=5.2 min CN=82 Runoff=0.96 cfs 0.042 af Runoff Area=18,405 sf 9.38% Impervious Runoff Depth=2.42"Subcatchment OFF-6: OFF-6 Flow Length=564' Slope=0.0323 '/' Tc=11.5 min CN=WQ Runoff=1.47 cfs 0.085 af Runoff Area=2,943 sf 9.17% Impervious Runoff Depth=2.42"Subcatchment OFF-7: OFF-7 Flow Length=429' Tc=7.1 min UI Adjusted CN=WQ Runoff=0.28 cfs 0.014 af Runoff Area=70,469 sf 31.01% Impervious Runoff Depth=2.81"Subcatchment OFF-8: OFF-8 Tc=10.0 min CN=WQ Runoff=6.64 cfs 0.378 af EDRN MSE 24-hr 3 10-Year Rainfall=4.26"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 35HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Runoff Area=30,431 sf 29.47% Impervious Runoff Depth=2.78"Subcatchment OFF-9: OFF-9 Tc=0.0 min CN=WQ Runoff=3.91 cfs 0.162 af Peak Elev=995.45' Storage=98,488 cf Inflow=59.68 cfs 3.226 afPond 1P: EXISTING POND 8.0" Round Culvert n=0.010 L=324.0' S=0.0080 '/' Outflow=1.75 cfs 3.223 af Peak Elev=997.09' Storage=551 cf Inflow=11.09 cfs 0.595 afPond 2P: West Ditch Primary=9.98 cfs 0.595 af Secondary=0.00 cfs 0.000 af Outflow=9.98 cfs 0.595 af Peak Elev=974.48' Storage=26,250 cf Inflow=13.92 cfs 4.013 afPond 10P: West Exisitng Wetland Outflow=3.58 cfs 4.013 af Inflow=9.32 cfs 0.440 afLink 3L: SOUTH Primary=9.32 cfs 0.440 af Inflow=8.04 cfs 0.461 afLink 5L: NORTHEAST Primary=8.04 cfs 0.461 af Inflow=1.16 cfs 0.047 afLink 6L: EAST Primary=1.16 cfs 0.047 af Inflow=21.06 cfs 5.124 afLink 7L: TOTAL Primary=21.06 cfs 5.124 af Inflow=3.91 cfs 0.162 afLink 8L: Existing to NORTHWEST Primary=3.91 cfs 0.162 af EDRN MSE 24-hr 3 10-Year Rainfall=4.26"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 36HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment E1: E1 Runoff = 27.35 cfs @ 12.14 hrs, Volume= 1.274 af, Depth= 2.43" Routed to Pond 1P : EXISTING POND Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 10-Year Rainfall=4.26" Area (sf) CN Description 1,904 98 Unconnected roofs, HSG D 24,173 98 Water Surface, HSG D 248,338 80 >75% Grass cover, Good, HSG D 274,415 Weighted Average 248,338 90.50% Pervious Area 26,077 9.50% Impervious Area 1,904 7.30% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.3 498 0.0723 1.31 Lag/CN Method, Subcatchment E1: E1 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)30 28 26 24 22 20 18 16 14 12 10 8 6 4 2 0 MSE 24-hr 3 10-Year Rainfall=4.26" Runoff Area=274,415 sf Runoff Volume=1.274 af Runoff Depth=2.43" Flow Length=498' Slope=0.0723 '/' Tc=6.3 min CN=WQ 27.35 cfs EDRN MSE 24-hr 3 10-Year Rainfall=4.26"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 37HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment E2: E2 Runoff = 7.54 cfs @ 12.22 hrs, Volume= 0.467 af, Depth= 2.33" Routed to Pond 1P : EXISTING POND Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 10-Year Rainfall=4.26" Area (ac) CN Adj Description 0.104 98 98 Unconnected roofs, HSG D 2.297 80 80 >75% Grass cover, Good, HSG D 2.401 Weighted Average 2.297 95.67% Pervious Area 0.104 4.33% Impervious Area 0.104 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 12.6 680 0.0323 0.90 Lag/CN Method, OVERLAND - SWALE 1.0 Direct Entry, STORM SEWER 13.6 680 Total Subcatchment E2: E2 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)8 7 6 5 4 3 2 1 0 MSE 24-hr 3 10-Year Rainfall=4.26" Runoff Area=2.401 ac Runoff Volume=0.467 af Runoff Depth=2.33" Flow Length=680' Slope=0.0323 '/' Tc=13.6 min UI Adjusted CN=WQ 7.54 cfs EDRN MSE 24-hr 3 10-Year Rainfall=4.26"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 38HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment E3: E3 Runoff = 8.12 cfs @ 12.13 hrs, Volume= 0.355 af, Depth= 2.26" Routed to Link 3L : SOUTH Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 10-Year Rainfall=4.26" Area (ac) CN Description 1.887 80 >75% Grass cover, Good, HSG D 1.887 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.5 327 0.0550 0.98 Lag/CN Method, OVERLAND Subcatchment E3: E3 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)9 8 7 6 5 4 3 2 1 0 MSE 24-hr 3 10-Year Rainfall=4.26" Runoff Area=1.887 ac Runoff Volume=0.355 af Runoff Depth=2.26" Flow Length=327' Slope=0.0550 '/' Tc=5.5 min CN=80 8.12 cfs EDRN MSE 24-hr 3 10-Year Rainfall=4.26"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 39HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment E4: E4 Runoff = 10.37 cfs @ 12.17 hrs, Volume= 0.554 af, Depth= 2.36" Routed to Pond 2P : West Ditch Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 10-Year Rainfall=4.26" Area (sf) CN Adj Description 12,084 98 98 Unconnected roofs, HSG D 110,597 79 79 Woods/grass comb., Good, HSG D 122,681 Weighted Average 110,597 90.15% Pervious Area 12,084 9.85% Impervious Area 12,084 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.8 385 0.0620 1.11 Lag/CN Method, OVERLAND 1.1 100 0.2000 1.53 Lag/CN Method, 2.5 65 0.0198 0.44 Lag/CN Method, 9.4 550 Total Subcatchment E4: E4 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)11 10 9 8 7 6 5 4 3 2 1 0 MSE 24-hr 3 10-Year Rainfall=4.26" Runoff Area=122,681 sf Runoff Volume=0.554 af Runoff Depth=2.36" Flow Length=550' Tc=9.4 min UI Adjusted CN=WQ 10.37 cfs EDRN MSE 24-hr 3 10-Year Rainfall=4.26"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 40HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment E5: E5 Runoff = 1.99 cfs @ 12.12 hrs, Volume= 0.083 af, Depth= 2.18" Routed to Link 5L : NORTHEAST Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 10-Year Rainfall=4.26" Area (ac) CN Description 0.458 79 Woods/grass comb., Good, HSG D 0.458 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 4.5 198 0.0404 0.74 Lag/CN Method, OVERLAND Subcatchment E5: E5 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)2 1 0 MSE 24-hr 3 10-Year Rainfall=4.26" Runoff Area=0.458 ac Runoff Volume=0.083 af Runoff Depth=2.18" Flow Length=198' Slope=0.0404 '/' Tc=4.5 min CN=79 1.99 cfs EDRN MSE 24-hr 3 10-Year Rainfall=4.26"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 41HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment E6: E6 Runoff = 1.16 cfs @ 12.11 hrs, Volume= 0.047 af, Depth= 2.18" Routed to Link 6L : EAST Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 10-Year Rainfall=4.26" Area (ac) CN Description 0.260 79 Woods/grass comb., Good, HSG D 0.260 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 3.7 136 0.0330 0.62 Lag/CN Method, OVERLAND Subcatchment E6: E6 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)1 0 MSE 24-hr 3 10-Year Rainfall=4.26" Runoff Area=0.260 ac Runoff Volume=0.047 af Runoff Depth=2.18" Flow Length=136' Slope=0.0330 '/' Tc=3.7 min CN=79 1.16 cfs EDRN MSE 24-hr 3 10-Year Rainfall=4.26"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 42HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment E7: E7 Runoff = 0.80 cfs @ 12.14 hrs, Volume= 0.037 af, Depth= 2.44" Routed to Pond 1P : EXISTING POND Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 10-Year Rainfall=4.26" Area (ac) CN Description 0.019 98 Paved parking, HSG D 0.164 80 >75% Grass cover, Good, HSG D 0.183 Weighted Average 0.164 89.62% Pervious Area 0.019 10.38% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.3 155 0.0160 0.49 Lag/CN Method, OVERLAND 1.0 Direct Entry, STORM SEWER 6.3 155 Total Subcatchment E7: E7 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)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=4.26" Runoff Area=0.183 ac Runoff Volume=0.037 af Runoff Depth=2.44" Flow Length=155' Slope=0.0160 '/' Tc=6.3 min CN=WQ 0.80 cfs EDRN MSE 24-hr 3 10-Year Rainfall=4.26"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 43HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment E8: E8 Runoff = 1.48 cfs @ 12.10 hrs, Volume= 0.059 af, Depth= 2.78" Routed to Pond 10P : West Exisitng Wetland Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 10-Year Rainfall=4.26" Area (sf) CN Description 11,092 86 Woods/grass comb., Poor, HSG D 11,092 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 1.0 Direct Entry, Subcatchment E8: E8 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)1 0 MSE 24-hr 3 10-Year Rainfall=4.26" Runoff Area=11,092 sf Runoff Volume=0.059 af Runoff Depth=2.78" Tc=1.0 min CN=86 1.48 cfs EDRN MSE 24-hr 3 10-Year Rainfall=4.26"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 44HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment OFF-1: OFF-1 Runoff = 15.68 cfs @ 12.17 hrs, Volume= 0.906 af, Depth= 2.98" Routed to Pond 1P : EXISTING POND Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 10-Year Rainfall=4.26" Area (ac) CN Description 1.590 98 Paved parking, HSG D 2.053 79 Woods/grass comb., Good, HSG D 3.643 Weighted Average 2.053 56.35% Pervious Area 1.590 43.65% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 8.8 564 0.0323 1.07 Lag/CN Method, BACK YARD SWALE 1.0 Direct Entry, Storm Sewer 9.8 564 Total Subcatchment OFF-1: OFF-1 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 MSE 24-hr 3 10-Year Rainfall=4.26" Runoff Area=3.643 ac Runoff Volume=0.906 af Runoff Depth=2.98" Flow Length=564' Slope=0.0323 '/' Tc=9.8 min CN=WQ 15.68 cfs EDRN MSE 24-hr 3 10-Year Rainfall=4.26"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 45HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment OFF-2: OFF-2 Runoff = 2.03 cfs @ 12.11 hrs, Volume= 0.088 af, Depth= 2.60" Routed to Pond 1P : EXISTING POND Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 10-Year Rainfall=4.26" Area (ac) CN Adj Description 0.092 98 98 Unconnected roofs, HSG D 0.314 79 79 Woods/grass comb., Good, HSG D 0.406 Weighted Average 0.314 77.34% Pervious Area 0.092 22.66% Impervious Area 0.092 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 3.7 270 0.0741 1.21 Lag/CN Method, Subcatchment OFF-2: OFF-2 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)2 1 0 MSE 24-hr 3 10-Year Rainfall=4.26" Runoff Area=0.406 ac Runoff Volume=0.088 af Runoff Depth=2.60" Flow Length=270' Slope=0.0741 '/' Tc=3.7 min UI Adjusted CN=WQ 2.03 cfs EDRN MSE 24-hr 3 10-Year Rainfall=4.26"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 46HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment OFF-3: OFF-3 Runoff = 9.06 cfs @ 12.14 hrs, Volume= 0.441 af, Depth= 2.68" Routed to Pond 1P : EXISTING POND Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 10-Year Rainfall=4.26" Area (sf) CN Description 23,261 98 Paved parking, HSG D 62,821 79 Woods/grass comb., Good, HSG D 86,082 Weighted Average 62,821 72.98% Pervious Area 23,261 27.02% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.4 489 0.0613 1.28 Lag/CN Method, Subcatchment OFF-3: OFF-3 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)10 9 8 7 6 5 4 3 2 1 0 MSE 24-hr 3 10-Year Rainfall=4.26" Runoff Area=86,082 sf Runoff Volume=0.441 af Runoff Depth=2.68" Flow Length=489' Slope=0.0613 '/' Tc=6.4 min CN=WQ 9.06 cfs EDRN MSE 24-hr 3 10-Year Rainfall=4.26"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 47HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment OFF-4: OFF-4 Runoff = 2.76 cfs @ 12.13 hrs, Volume= 0.135 af, Depth= 3.03" Routed to Pond 10P : West Exisitng Wetland Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 10-Year Rainfall=4.26" Area (sf) CN Description 10,240 98 Paved parking, HSG D 13,095 80 >75% Grass cover, Good, HSG D 23,335 Weighted Average 13,095 56.12% Pervious Area 10,240 43.88% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.9 337 0.0297 0.96 Lag/CN Method, Subcatchment OFF-4: OFF-4 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)3 2 1 0 MSE 24-hr 3 10-Year Rainfall=4.26" Runoff Area=23,335 sf Runoff Volume=0.135 af Runoff Depth=3.03" Flow Length=337' Slope=0.0297 '/' Tc=5.9 min CN=WQ 2.76 cfs EDRN MSE 24-hr 3 10-Year Rainfall=4.26"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 48HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment OFF-5: OFF-5 Runoff = 0.96 cfs @ 12.13 hrs, Volume= 0.042 af, Depth= 2.43" Routed to Pond 2P : West Ditch Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 10-Year Rainfall=4.26" Area (sf) CN Description 8,976 82 Woods/grass comb., Fair, HSG D 8,976 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 1.6 194 0.2474 2.00 Lag/CN Method, 3.6 155 0.0354 0.72 Lag/CN Method, 5.2 349 Total Subcatchment OFF-5: OFF-5 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)1 0 MSE 24-hr 3 10-Year Rainfall=4.26" Runoff Area=8,976 sf Runoff Volume=0.042 af Runoff Depth=2.43" Flow Length=349' Tc=5.2 min CN=82 0.96 cfs EDRN MSE 24-hr 3 10-Year Rainfall=4.26"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 49HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment OFF-6: OFF-6 Runoff = 1.47 cfs @ 12.19 hrs, Volume= 0.085 af, Depth= 2.42" Routed to Link 3L : SOUTH Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 10-Year Rainfall=4.26" Area (sf) CN Description * 1,727 98 Impervious, HSG D 16,678 80 >75% Grass cover, Good, HSG D 18,405 Weighted Average 16,678 90.62% Pervious Area 1,727 9.38% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.5 564 0.0323 0.90 Lag/CN Method, BACK YARD SWALE 1.0 Direct Entry, Storm Sewer 11.5 564 Total Subcatchment OFF-6: OFF-6 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)1 0 MSE 24-hr 3 10-Year Rainfall=4.26" Runoff Area=18,405 sf Runoff Volume=0.085 af Runoff Depth=2.42" Flow Length=564' Slope=0.0323 '/' Tc=11.5 min CN=WQ 1.47 cfs EDRN MSE 24-hr 3 10-Year Rainfall=4.26"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 50HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment OFF-7: OFF-7 Runoff = 0.28 cfs @ 12.14 hrs, Volume= 0.014 af, Depth= 2.42" Routed to Pond 1P : EXISTING POND Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 10-Year Rainfall=4.26" Area (sf) CN Adj Description 2,673 80 80 >75% Grass cover, Good, HSG D 270 98 98 Unconnected roofs, HSG D 2,943 Weighted Average 2,673 90.83% Pervious Area 270 9.17% Impervious Area 270 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 1.1 83 0.1445 1.29 Lag/CN Method, 6.0 346 0.0448 0.96 Lag/CN Method, 7.1 429 Total Subcatchment OFF-7: OFF-7 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)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 10-Year Rainfall=4.26" Runoff Area=2,943 sf Runoff Volume=0.014 af Runoff Depth=2.42" Flow Length=429' Tc=7.1 min UI Adjusted CN=WQ 0.28 cfs EDRN MSE 24-hr 3 10-Year Rainfall=4.26"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 51HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment OFF-8: OFF-8 Runoff = 6.64 cfs @ 12.17 hrs, Volume= 0.378 af, Depth= 2.81" Routed to Link 5L : NORTHEAST Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 10-Year Rainfall=4.26" Area (sf) CN Description 21,849 98 Paved parking, HSG D 48,620 80 >75% Grass cover, Good, HSG D 70,469 Weighted Average 48,620 68.99% Pervious Area 21,849 31.01% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, storm sewer Subcatchment OFF-8: OFF-8 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)7 6 5 4 3 2 1 0 MSE 24-hr 3 10-Year Rainfall=4.26" Runoff Area=70,469 sf Runoff Volume=0.378 af Runoff Depth=2.81" Tc=10.0 min CN=WQ 6.64 cfs EDRN MSE 24-hr 3 10-Year Rainfall=4.26"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 52HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment OFF-9: OFF-9 Runoff = 3.91 cfs @ 12.09 hrs, Volume= 0.162 af, Depth= 2.78" Routed to Link 8L : Existing to NORTHWEST Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 10-Year Rainfall=4.26" Area (sf) CN Description 8,967 98 Paved parking, HSG D 21,464 80 >75% Grass cover, Good, HSG D 30,431 Weighted Average 21,464 70.53% Pervious Area 8,967 29.47% Impervious Area Subcatchment OFF-9: OFF-9 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)4 3 2 1 0 MSE 24-hr 3 10-Year Rainfall=4.26" Runoff Area=30,431 sf Runoff Volume=0.162 af Runoff Depth=2.78" Tc=0.0 min CN=WQ 3.91 cfs EDRN MSE 24-hr 3 10-Year Rainfall=4.26"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 53HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Pond 1P: EXISTING POND Inflow Area = 14.976 ac, 19.66% Impervious, Inflow Depth = 2.58" for 10-Year event Inflow = 59.68 cfs @ 12.14 hrs, Volume= 3.226 af Outflow = 1.75 cfs @ 15.04 hrs, Volume= 3.223 af, Atten= 97%, Lag= 173.6 min Primary = 1.75 cfs @ 15.04 hrs, Volume= 3.223 af Routed to Pond 10P : West Exisitng Wetland Routing by Dyn-Stor-Ind method, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs Peak Elev= 995.45' @ 15.04 hrs Surf.Area= 51,737 sf Storage= 98,488 cf Plug-Flow detention time= 729.1 min calculated for 3.223 af (100% of inflow) Center-of-Mass det. time= 729.1 min ( 1,518.7 - 789.6 ) Volume Invert Avail.Storage Storage Description #1 992.61' 277,554 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 992.61 24,173 0 0 994.00 31,142 38,444 38,444 996.00 59,569 90,711 129,155 998.00 88,830 148,399 277,554 Device Routing Invert Outlet Devices #1 Primary 992.61'8.0" Round Culvert L= 324.0' CPP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 992.61' / 990.02' S= 0.0080 '/' Cc= 0.900 n= 0.010 PVC, smooth interior, Flow Area= 0.35 sf Primary OutFlow Max=1.75 cfs @ 15.04 hrs HW=995.45' TW=974.40' (Dynamic Tailwater) 1=Culvert (Barrel Controls 1.75 cfs @ 5.01 fps) EDRN MSE 24-hr 3 10-Year Rainfall=4.26"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 54HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Pond 1P: EXISTING POND Inflow Primary Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)65 60 55 50 45 40 35 30 25 20 15 10 5 0 Inflow Area=14.976 ac Peak Elev=995.45' Storage=98,488 cf 8.0" Round Culvert n=0.010 L=324.0' S=0.0080 '/' 59.68 cfs 1.75 cfs EDRN MSE 24-hr 3 10-Year Rainfall=4.26"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 55HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Pond 2P: West Ditch Inflow Area = 3.022 ac, 9.18% Impervious, Inflow Depth = 2.36" for 10-Year event Inflow = 11.09 cfs @ 12.16 hrs, Volume= 0.595 af Outflow = 9.98 cfs @ 12.20 hrs, Volume= 0.595 af, Atten= 10%, Lag= 2.4 min Primary = 9.98 cfs @ 12.20 hrs, Volume= 0.595 af Routed to Pond 10P : West Exisitng Wetland Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Routed to Pond 10P : West Exisitng Wetland Routing by Dyn-Stor-Ind method, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs Peak Elev= 997.09' @ 12.20 hrs Surf.Area= 948 sf Storage= 551 cf Plug-Flow detention time= (not calculated: outflow precedes inflow) Center-of-Mass det. time= 0.2 min ( 799.9 - 799.7 ) Volume Invert Avail.Storage Storage Description #1 995.00' 5,727 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 995.00 5 0 0 996.00 59 32 32 997.00 825 442 474 998.00 2,243 1,534 2,008 998.60 4,093 1,901 3,909 999.00 5,000 1,819 5,727 Device Routing Invert Outlet Devices #1 Primary 994.57'18.0" Round CMP_Round 18" L= 57.1' CMP, mitered to conform to fill, Ke= 0.700 Inlet / Outlet Invert= 994.57' / 989.52' S= 0.0884 '/' Cc= 0.900 n= 0.025 Corrugated metal, Flow Area= 1.77 sf #2 Secondary 998.59'20.0' long x 16.0' breadth Existing Berm Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 Coef. (English) 2.68 2.70 2.70 2.64 2.63 2.64 2.64 2.63 Primary OutFlow Max=9.97 cfs @ 12.20 hrs HW=997.08' TW=974.38' (Dynamic Tailwater) 1=CMP_Round 18" (Inlet Controls 9.97 cfs @ 5.64 fps) Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=995.00' TW=974.10' (Dynamic Tailwater) 2=Existing Berm ( Controls 0.00 cfs) EDRN MSE 24-hr 3 10-Year Rainfall=4.26"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 56HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Pond 2P: West Ditch Inflow Outflow Primary Secondary Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)12 11 10 9 8 7 6 5 4 3 2 1 0 Inflow Area=3.022 ac Peak Elev=997.09' Storage=551 cf 11.09 cfs 9.98 cfs 9.98 cfs 0.00 cfs EDRN MSE 24-hr 3 10-Year Rainfall=4.26"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 57HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Pond 10P: West Exisitng Wetland Inflow Area = 18.789 ac, 18.40% Impervious, Inflow Depth = 2.56" for 10-Year event Inflow = 13.92 cfs @ 12.17 hrs, Volume= 4.013 af Outflow = 3.58 cfs @ 12.66 hrs, Volume= 4.013 af, Atten= 74%, Lag= 29.6 min Primary = 3.58 cfs @ 12.66 hrs, Volume= 4.013 af Routed to Link 7L : TOTAL Routing by Dyn-Stor-Ind method, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs Starting Elev= 974.10' Surf.Area= 54,326 sf Storage= 5,411 cf Peak Elev= 974.48' @ 12.66 hrs Surf.Area= 55,964 sf Storage= 26,250 cf (20,839 cf above start) Plug-Flow detention time= 270.2 min calculated for 3.889 af (97% of inflow) Center-of-Mass det. time= 143.4 min ( 1,519.5 - 1,376.1 ) Volume Invert Avail.Storage Storage Description #1 974.00' 487,616 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 974.00 53,893 0 0 975.00 58,226 56,060 56,060 976.00 62,886 60,556 116,616 977.00 67,093 64,990 181,605 978.00 71,582 69,338 250,943 979.00 76,083 73,833 324,775 980.00 81,311 78,697 403,472 981.00 86,977 84,144 487,616 Device Routing Invert Outlet Devices #1 Primary 974.10'18.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads Primary OutFlow Max=3.58 cfs @ 12.66 hrs HW=974.48' TW=0.00' (Dynamic Tailwater) 1=Orifice/Grate (Weir Controls 3.58 cfs @ 2.01 fps) EDRN MSE 24-hr 3 10-Year Rainfall=4.26"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 58HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Pond 10P: West Exisitng Wetland Inflow Primary Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Inflow Area=18.789 ac Peak Elev=974.48' Storage=26,250 cf 13.92 cfs 3.58 cfs EDRN MSE 24-hr 3 10-Year Rainfall=4.26"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 59HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Link 3L: SOUTH Inflow Area = 2.310 ac, 1.72% Impervious, Inflow Depth = 2.29" for 10-Year event Inflow = 9.32 cfs @ 12.13 hrs, Volume= 0.440 af Primary = 9.32 cfs @ 12.13 hrs, Volume= 0.440 af, Atten= 0%, Lag= 0.0 min Routed to Link 7L : TOTAL Primary outflow = Inflow, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs Link 3L: SOUTH Inflow Primary Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)10 9 8 7 6 5 4 3 2 1 0 Inflow Area=2.310 ac 9.32 cfs 9.32 cfs EDRN MSE 24-hr 3 10-Year Rainfall=4.26"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 60HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Link 5L: NORTHEAST Inflow Area = 2.076 ac, 24.16% Impervious, Inflow Depth = 2.67" for 10-Year event Inflow = 8.04 cfs @ 12.15 hrs, Volume= 0.461 af Primary = 8.04 cfs @ 12.15 hrs, Volume= 0.461 af, Atten= 0%, Lag= 0.0 min Routed to Link 7L : TOTAL Primary outflow = Inflow, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs Link 5L: NORTHEAST Inflow Primary Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)9 8 7 6 5 4 3 2 1 0 Inflow Area=2.076 ac 8.04 cfs 8.04 cfs EDRN MSE 24-hr 3 10-Year Rainfall=4.26"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 61HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Link 6L: EAST Inflow Area = 0.260 ac, 0.00% Impervious, Inflow Depth = 2.18" for 10-Year event Inflow = 1.16 cfs @ 12.11 hrs, Volume= 0.047 af Primary = 1.16 cfs @ 12.11 hrs, Volume= 0.047 af, Atten= 0%, Lag= 0.0 min Routed to Link 7L : TOTAL Primary outflow = Inflow, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs Link 6L: EAST Inflow Primary Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)1 0 Inflow Area=0.260 ac 1.16 cfs 1.16 cfs EDRN MSE 24-hr 3 10-Year Rainfall=4.26"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 62HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Link 7L: TOTAL Inflow Area = 24.133 ac, 17.42% Impervious, Inflow Depth = 2.55" for 10-Year event Inflow = 21.06 cfs @ 12.14 hrs, Volume= 5.124 af Primary = 21.06 cfs @ 12.14 hrs, Volume= 5.124 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs Link 7L: TOTAL Inflow Primary Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Inflow Area=24.133 ac 21.06 cfs 21.06 cfs EDRN MSE 24-hr 3 10-Year Rainfall=4.26"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 63HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Link 8L: Existing to NORTHWEST Inflow Area = 0.699 ac, 29.47% Impervious, Inflow Depth = 2.78" for 10-Year event Inflow = 3.91 cfs @ 12.09 hrs, Volume= 0.162 af Primary = 3.91 cfs @ 12.09 hrs, Volume= 0.162 af, Atten= 0%, Lag= 0.0 min Routed to Link 7L : TOTAL Primary outflow = Inflow, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs Link 8L: Existing to NORTHWEST Inflow Primary Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)4 3 2 1 0 Inflow Area=0.699 ac 3.91 cfs 3.91 cfs EDRN MSE 24-hr 3 100-Year Rainfall=7.38"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 64HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Time span=0.00-600.00 hrs, dt=0.01 hrs, 60001 points Runoff by SCS TR-20 method, UH=SCS, Weighted-Q Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method Runoff Area=274,415 sf 9.50% Impervious Runoff Depth=5.25"Subcatchment E1: E1 Flow Length=498' Slope=0.0723 '/' Tc=6.3 min CN=WQ Runoff=57.64 cfs 2.754 af Runoff Area=2.401 ac 4.33% Impervious Runoff Depth=5.14"Subcatchment E2: E2 Flow Length=680' Slope=0.0323 '/' Tc=13.6 min UI Adjusted CN=WQ Runoff=16.32 cfs 1.028 af Runoff Area=1.887 ac 0.00% Impervious Runoff Depth=5.05"Subcatchment E3: E3 Flow Length=327' Slope=0.0550 '/' Tc=5.5 min CN=80 Runoff=17.55 cfs 0.794 af Runoff Area=122,681 sf 9.85% Impervious Runoff Depth=5.15"Subcatchment E4: E4 Flow Length=550' Tc=9.4 min UI Adjusted CN=WQ Runoff=22.28 cfs 1.209 af Runoff Area=0.458 ac 0.00% Impervious Runoff Depth=4.93"Subcatchment E5: E5 Flow Length=198' Slope=0.0404 '/' Tc=4.5 min CN=79 Runoff=4.35 cfs 0.188 af Runoff Area=0.260 ac 0.00% Impervious Runoff Depth=4.93"Subcatchment E6: E6 Flow Length=136' Slope=0.0330 '/' Tc=3.7 min CN=79 Runoff=2.53 cfs 0.107 af Runoff Area=0.183 ac 10.38% Impervious Runoff Depth=5.26"Subcatchment E7: E7 Flow Length=155' Slope=0.0160 '/' Tc=6.3 min CN=WQ Runoff=1.68 cfs 0.080 af Runoff Area=11,092 sf 0.00% Impervious Runoff Depth=5.73"Subcatchment E8: E8 Tc=1.0 min CN=86 Runoff=2.86 cfs 0.122 af Runoff Area=3.643 ac 43.65% Impervious Runoff Depth=5.90"Subcatchment OFF-1: OFF-1 Flow Length=564' Slope=0.0323 '/' Tc=9.8 min CN=WQ Runoff=30.69 cfs 1.790 af Runoff Area=0.406 ac 22.66% Impervious Runoff Depth=5.43"Subcatchment OFF-2: OFF-2 Flow Length=270' Slope=0.0741 '/' Tc=3.7 min UI Adjusted CN=WQ Runoff=4.15 cfs 0.184 af Runoff Area=86,082 sf 27.02% Impervious Runoff Depth=5.53"Subcatchment OFF-3: OFF-3 Flow Length=489' Slope=0.0613 '/' Tc=6.4 min CN=WQ Runoff=18.44 cfs 0.911 af Runoff Area=23,335 sf 43.88% Impervious Runoff Depth=5.97"Subcatchment OFF-4: OFF-4 Flow Length=337' Slope=0.0297 '/' Tc=5.9 min CN=WQ Runoff=5.35 cfs 0.266 af Runoff Area=8,976 sf 0.00% Impervious Runoff Depth=5.27"Subcatchment OFF-5: OFF-5 Flow Length=349' Tc=5.2 min CN=82 Runoff=2.00 cfs 0.091 af Runoff Area=18,405 sf 9.38% Impervious Runoff Depth=5.24"Subcatchment OFF-6: OFF-6 Flow Length=564' Slope=0.0323 '/' Tc=11.5 min CN=WQ Runoff=3.12 cfs 0.185 af Runoff Area=2,943 sf 9.17% Impervious Runoff Depth=5.24"Subcatchment OFF-7: OFF-7 Flow Length=429' Tc=7.1 min UI Adjusted CN=WQ Runoff=0.60 cfs 0.029 af Runoff Area=70,469 sf 31.01% Impervious Runoff Depth=5.70"Subcatchment OFF-8: OFF-8 Tc=10.0 min CN=WQ Runoff=13.30 cfs 0.768 af EDRN MSE 24-hr 3 100-Year Rainfall=7.38"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 65HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Runoff Area=30,431 sf 29.47% Impervious Runoff Depth=5.66"Subcatchment OFF-9: OFF-9 Tc=0.0 min CN=WQ Runoff=7.66 cfs 0.330 af Peak Elev=997.39' Storage=226,085 cf Inflow=123.52 cfs 6.776 afPond 1P: EXISTING POND 8.0" Round Culvert n=0.010 L=324.0' S=0.0080 '/' Outflow=2.07 cfs 6.773 af Peak Elev=998.80' Storage=4,751 cf Inflow=23.82 cfs 1.299 afPond 2P: West Ditch Primary=14.00 cfs 1.265 af Secondary=4.98 cfs 0.035 af Outflow=18.98 cfs 1.299 af Peak Elev=974.85' Storage=47,132 cf Inflow=24.07 cfs 8.461 afPond 10P: West Exisitng Wetland Outflow=7.35 cfs 8.460 af Inflow=20.13 cfs 0.978 afLink 3L: SOUTH Primary=20.13 cfs 0.978 af Inflow=16.45 cfs 0.956 afLink 5L: NORTHEAST Primary=16.45 cfs 0.956 af Inflow=2.53 cfs 0.107 afLink 6L: EAST Primary=2.53 cfs 0.107 af Inflow=45.65 cfs 10.831 afLink 7L: TOTAL Primary=45.65 cfs 10.831 af Inflow=7.66 cfs 0.330 afLink 8L: Existing to NORTHWEST Primary=7.66 cfs 0.330 af EDRN MSE 24-hr 3 100-Year Rainfall=7.38"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 66HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment E1: E1 Runoff = 57.64 cfs @ 12.13 hrs, Volume= 2.754 af, Depth= 5.25" Routed to Pond 1P : EXISTING POND Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 100-Year Rainfall=7.38" Area (sf) CN Description 1,904 98 Unconnected roofs, HSG D 24,173 98 Water Surface, HSG D 248,338 80 >75% Grass cover, Good, HSG D 274,415 Weighted Average 248,338 90.50% Pervious Area 26,077 9.50% Impervious Area 1,904 7.30% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.3 498 0.0723 1.31 Lag/CN Method, Subcatchment E1: E1 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)60 55 50 45 40 35 30 25 20 15 10 5 0 MSE 24-hr 3 100-Year Rainfall=7.38" Runoff Area=274,415 sf Runoff Volume=2.754 af Runoff Depth=5.25" Flow Length=498' Slope=0.0723 '/' Tc=6.3 min CN=WQ 57.64 cfs EDRN MSE 24-hr 3 100-Year Rainfall=7.38"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 67HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment E2: E2 Runoff = 16.32 cfs @ 12.22 hrs, Volume= 1.028 af, Depth= 5.14" Routed to Pond 1P : EXISTING POND Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 100-Year Rainfall=7.38" Area (ac) CN Adj Description 0.104 98 98 Unconnected roofs, HSG D 2.297 80 80 >75% Grass cover, Good, HSG D 2.401 Weighted Average 2.297 95.67% Pervious Area 0.104 4.33% Impervious Area 0.104 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 12.6 680 0.0323 0.90 Lag/CN Method, OVERLAND - SWALE 1.0 Direct Entry, STORM SEWER 13.6 680 Total Subcatchment E2: E2 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 MSE 24-hr 3 100-Year Rainfall=7.38" Runoff Area=2.401 ac Runoff Volume=1.028 af Runoff Depth=5.14" Flow Length=680' Slope=0.0323 '/' Tc=13.6 min UI Adjusted CN=WQ 16.32 cfs EDRN MSE 24-hr 3 100-Year Rainfall=7.38"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 68HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment E3: E3 Runoff = 17.55 cfs @ 12.13 hrs, Volume= 0.794 af, Depth= 5.05" Routed to Link 3L : SOUTH Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 100-Year Rainfall=7.38" Area (ac) CN Description 1.887 80 >75% Grass cover, Good, HSG D 1.887 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.5 327 0.0550 0.98 Lag/CN Method, OVERLAND Subcatchment E3: E3 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 MSE 24-hr 3 100-Year Rainfall=7.38" Runoff Area=1.887 ac Runoff Volume=0.794 af Runoff Depth=5.05" Flow Length=327' Slope=0.0550 '/' Tc=5.5 min CN=80 17.55 cfs EDRN MSE 24-hr 3 100-Year Rainfall=7.38"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 69HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment E4: E4 Runoff = 22.28 cfs @ 12.17 hrs, Volume= 1.209 af, Depth= 5.15" Routed to Pond 2P : West Ditch Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 100-Year Rainfall=7.38" Area (sf) CN Adj Description 12,084 98 98 Unconnected roofs, HSG D 110,597 79 79 Woods/grass comb., Good, HSG D 122,681 Weighted Average 110,597 90.15% Pervious Area 12,084 9.85% Impervious Area 12,084 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.8 385 0.0620 1.11 Lag/CN Method, OVERLAND 1.1 100 0.2000 1.53 Lag/CN Method, 2.5 65 0.0198 0.44 Lag/CN Method, 9.4 550 Total Subcatchment E4: E4 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 MSE 24-hr 3 100-Year Rainfall=7.38" Runoff Area=122,681 sf Runoff Volume=1.209 af Runoff Depth=5.15" Flow Length=550' Tc=9.4 min UI Adjusted CN=WQ 22.28 cfs EDRN MSE 24-hr 3 100-Year Rainfall=7.38"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 70HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment E5: E5 Runoff = 4.35 cfs @ 12.12 hrs, Volume= 0.188 af, Depth= 4.93" Routed to Link 5L : NORTHEAST Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 100-Year Rainfall=7.38" Area (ac) CN Description 0.458 79 Woods/grass comb., Good, HSG D 0.458 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 4.5 198 0.0404 0.74 Lag/CN Method, OVERLAND Subcatchment E5: E5 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)4 3 2 1 0 MSE 24-hr 3 100-Year Rainfall=7.38" Runoff Area=0.458 ac Runoff Volume=0.188 af Runoff Depth=4.93" Flow Length=198' Slope=0.0404 '/' Tc=4.5 min CN=79 4.35 cfs EDRN MSE 24-hr 3 100-Year Rainfall=7.38"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 71HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment E6: E6 Runoff = 2.53 cfs @ 12.11 hrs, Volume= 0.107 af, Depth= 4.93" Routed to Link 6L : EAST Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 100-Year Rainfall=7.38" Area (ac) CN Description 0.260 79 Woods/grass comb., Good, HSG D 0.260 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 3.7 136 0.0330 0.62 Lag/CN Method, OVERLAND Subcatchment E6: E6 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)2 1 0 MSE 24-hr 3 100-Year Rainfall=7.38" Runoff Area=0.260 ac Runoff Volume=0.107 af Runoff Depth=4.93" Flow Length=136' Slope=0.0330 '/' Tc=3.7 min CN=79 2.53 cfs EDRN MSE 24-hr 3 100-Year Rainfall=7.38"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 72HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment E7: E7 Runoff = 1.68 cfs @ 12.13 hrs, Volume= 0.080 af, Depth= 5.26" Routed to Pond 1P : EXISTING POND Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 100-Year Rainfall=7.38" Area (ac) CN Description 0.019 98 Paved parking, HSG D 0.164 80 >75% Grass cover, Good, HSG D 0.183 Weighted Average 0.164 89.62% Pervious Area 0.019 10.38% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.3 155 0.0160 0.49 Lag/CN Method, OVERLAND 1.0 Direct Entry, STORM SEWER 6.3 155 Total Subcatchment E7: E7 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)1 0 MSE 24-hr 3 100-Year Rainfall=7.38" Runoff Area=0.183 ac Runoff Volume=0.080 af Runoff Depth=5.26" Flow Length=155' Slope=0.0160 '/' Tc=6.3 min CN=WQ 1.68 cfs EDRN MSE 24-hr 3 100-Year Rainfall=7.38"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 73HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment E8: E8 Runoff = 2.86 cfs @ 12.10 hrs, Volume= 0.122 af, Depth= 5.73" Routed to Pond 10P : West Exisitng Wetland Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 100-Year Rainfall=7.38" Area (sf) CN Description 11,092 86 Woods/grass comb., Poor, HSG D 11,092 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 1.0 Direct Entry, Subcatchment E8: E8 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)3 2 1 0 MSE 24-hr 3 100-Year Rainfall=7.38" Runoff Area=11,092 sf Runoff Volume=0.122 af Runoff Depth=5.73" Tc=1.0 min CN=86 2.86 cfs EDRN MSE 24-hr 3 100-Year Rainfall=7.38"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 74HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment OFF-1: OFF-1 Runoff = 30.69 cfs @ 12.17 hrs, Volume= 1.790 af, Depth= 5.90" Routed to Pond 1P : EXISTING POND Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 100-Year Rainfall=7.38" Area (ac) CN Description 1.590 98 Paved parking, HSG D 2.053 79 Woods/grass comb., Good, HSG D 3.643 Weighted Average 2.053 56.35% Pervious Area 1.590 43.65% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 8.8 564 0.0323 1.07 Lag/CN Method, BACK YARD SWALE 1.0 Direct Entry, Storm Sewer 9.8 564 Total Subcatchment OFF-1: OFF-1 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)34 32 30 28 26 24 22 20 18 16 14 12 10 8 6 4 2 0 MSE 24-hr 3 100-Year Rainfall=7.38" Runoff Area=3.643 ac Runoff Volume=1.790 af Runoff Depth=5.90" Flow Length=564' Slope=0.0323 '/' Tc=9.8 min CN=WQ 30.69 cfs EDRN MSE 24-hr 3 100-Year Rainfall=7.38"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 75HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment OFF-2: OFF-2 Runoff = 4.15 cfs @ 12.11 hrs, Volume= 0.184 af, Depth= 5.43" Routed to Pond 1P : EXISTING POND Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 100-Year Rainfall=7.38" Area (ac) CN Adj Description 0.092 98 98 Unconnected roofs, HSG D 0.314 79 79 Woods/grass comb., Good, HSG D 0.406 Weighted Average 0.314 77.34% Pervious Area 0.092 22.66% Impervious Area 0.092 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 3.7 270 0.0741 1.21 Lag/CN Method, Subcatchment OFF-2: OFF-2 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)4 3 2 1 0 MSE 24-hr 3 100-Year Rainfall=7.38" Runoff Area=0.406 ac Runoff Volume=0.184 af Runoff Depth=5.43" Flow Length=270' Slope=0.0741 '/' Tc=3.7 min UI Adjusted CN=WQ 4.15 cfs EDRN MSE 24-hr 3 100-Year Rainfall=7.38"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 76HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment OFF-3: OFF-3 Runoff = 18.44 cfs @ 12.14 hrs, Volume= 0.911 af, Depth= 5.53" Routed to Pond 1P : EXISTING POND Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 100-Year Rainfall=7.38" Area (sf) CN Description 23,261 98 Paved parking, HSG D 62,821 79 Woods/grass comb., Good, HSG D 86,082 Weighted Average 62,821 72.98% Pervious Area 23,261 27.02% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.4 489 0.0613 1.28 Lag/CN Method, Subcatchment OFF-3: OFF-3 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 MSE 24-hr 3 100-Year Rainfall=7.38" Runoff Area=86,082 sf Runoff Volume=0.911 af Runoff Depth=5.53" Flow Length=489' Slope=0.0613 '/' Tc=6.4 min CN=WQ 18.44 cfs EDRN MSE 24-hr 3 100-Year Rainfall=7.38"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 77HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment OFF-4: OFF-4 Runoff = 5.35 cfs @ 12.13 hrs, Volume= 0.266 af, Depth= 5.97" Routed to Pond 10P : West Exisitng Wetland Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 100-Year Rainfall=7.38" Area (sf) CN Description 10,240 98 Paved parking, HSG D 13,095 80 >75% Grass cover, Good, HSG D 23,335 Weighted Average 13,095 56.12% Pervious Area 10,240 43.88% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.9 337 0.0297 0.96 Lag/CN Method, Subcatchment OFF-4: OFF-4 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)5 4 3 2 1 0 MSE 24-hr 3 100-Year Rainfall=7.38" Runoff Area=23,335 sf Runoff Volume=0.266 af Runoff Depth=5.97" Flow Length=337' Slope=0.0297 '/' Tc=5.9 min CN=WQ 5.35 cfs EDRN MSE 24-hr 3 100-Year Rainfall=7.38"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 78HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment OFF-5: OFF-5 Runoff = 2.00 cfs @ 12.12 hrs, Volume= 0.091 af, Depth= 5.27" Routed to Pond 2P : West Ditch Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 100-Year Rainfall=7.38" Area (sf) CN Description 8,976 82 Woods/grass comb., Fair, HSG D 8,976 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 1.6 194 0.2474 2.00 Lag/CN Method, 3.6 155 0.0354 0.72 Lag/CN Method, 5.2 349 Total Subcatchment OFF-5: OFF-5 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)2 1 0 MSE 24-hr 3 100-Year Rainfall=7.38" Runoff Area=8,976 sf Runoff Volume=0.091 af Runoff Depth=5.27" Flow Length=349' Tc=5.2 min CN=82 2.00 cfs EDRN MSE 24-hr 3 100-Year Rainfall=7.38"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 79HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment OFF-6: OFF-6 Runoff = 3.12 cfs @ 12.19 hrs, Volume= 0.185 af, Depth= 5.24" Routed to Link 3L : SOUTH Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 100-Year Rainfall=7.38" Area (sf) CN Description * 1,727 98 Impervious, HSG D 16,678 80 >75% Grass cover, Good, HSG D 18,405 Weighted Average 16,678 90.62% Pervious Area 1,727 9.38% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.5 564 0.0323 0.90 Lag/CN Method, BACK YARD SWALE 1.0 Direct Entry, Storm Sewer 11.5 564 Total Subcatchment OFF-6: OFF-6 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)3 2 1 0 MSE 24-hr 3 100-Year Rainfall=7.38" Runoff Area=18,405 sf Runoff Volume=0.185 af Runoff Depth=5.24" Flow Length=564' Slope=0.0323 '/' Tc=11.5 min CN=WQ 3.12 cfs EDRN MSE 24-hr 3 100-Year Rainfall=7.38"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 80HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment OFF-7: OFF-7 Runoff = 0.60 cfs @ 12.14 hrs, Volume= 0.029 af, Depth= 5.24" Routed to Pond 1P : EXISTING POND Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 100-Year Rainfall=7.38" Area (sf) CN Adj Description 2,673 80 80 >75% Grass cover, Good, HSG D 270 98 98 Unconnected roofs, HSG D 2,943 Weighted Average 2,673 90.83% Pervious Area 270 9.17% Impervious Area 270 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 1.1 83 0.1445 1.29 Lag/CN Method, 6.0 346 0.0448 0.96 Lag/CN Method, 7.1 429 Total Subcatchment OFF-7: OFF-7 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)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 3 100-Year Rainfall=7.38" Runoff Area=2,943 sf Runoff Volume=0.029 af Runoff Depth=5.24" Flow Length=429' Tc=7.1 min UI Adjusted CN=WQ 0.60 cfs EDRN MSE 24-hr 3 100-Year Rainfall=7.38"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 81HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment OFF-8: OFF-8 Runoff = 13.30 cfs @ 12.17 hrs, Volume= 0.768 af, Depth= 5.70" Routed to Link 5L : NORTHEAST Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 100-Year Rainfall=7.38" Area (sf) CN Description 21,849 98 Paved parking, HSG D 48,620 80 >75% Grass cover, Good, HSG D 70,469 Weighted Average 48,620 68.99% Pervious Area 21,849 31.01% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, storm sewer Subcatchment OFF-8: OFF-8 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 MSE 24-hr 3 100-Year Rainfall=7.38" Runoff Area=70,469 sf Runoff Volume=0.768 af Runoff Depth=5.70" Tc=10.0 min CN=WQ 13.30 cfs EDRN MSE 24-hr 3 100-Year Rainfall=7.38"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 82HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Subcatchment OFF-9: OFF-9 Runoff = 7.66 cfs @ 12.09 hrs, Volume= 0.330 af, Depth= 5.66" Routed to Link 8L : Existing to NORTHWEST Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 100-Year Rainfall=7.38" Area (sf) CN Description 8,967 98 Paved parking, HSG D 21,464 80 >75% Grass cover, Good, HSG D 30,431 Weighted Average 21,464 70.53% Pervious Area 8,967 29.47% Impervious Area Subcatchment OFF-9: OFF-9 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)8 7 6 5 4 3 2 1 0 MSE 24-hr 3 100-Year Rainfall=7.38" Runoff Area=30,431 sf Runoff Volume=0.330 af Runoff Depth=5.66" Tc=0.0 min CN=WQ 7.66 cfs EDRN MSE 24-hr 3 100-Year Rainfall=7.38"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 83HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Pond 1P: EXISTING POND Inflow Area = 14.976 ac, 19.66% Impervious, Inflow Depth = 5.43" for 100-Year event Inflow = 123.52 cfs @ 12.14 hrs, Volume= 6.776 af Outflow = 2.07 cfs @ 15.38 hrs, Volume= 6.773 af, Atten= 98%, Lag= 194.6 min Primary = 2.07 cfs @ 15.38 hrs, Volume= 6.773 af Routed to Pond 10P : West Exisitng Wetland Routing by Dyn-Stor-Ind method, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs Peak Elev= 997.39' @ 15.38 hrs Surf.Area= 79,905 sf Storage= 226,085 cf Plug-Flow detention time= 1,201.5 min calculated for 6.773 af (100% of inflow) Center-of-Mass det. time= 1,201.3 min ( 1,979.8 - 778.5 ) Volume Invert Avail.Storage Storage Description #1 992.61' 277,554 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 992.61 24,173 0 0 994.00 31,142 38,444 38,444 996.00 59,569 90,711 129,155 998.00 88,830 148,399 277,554 Device Routing Invert Outlet Devices #1 Primary 992.61'8.0" Round Culvert L= 324.0' CPP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 992.61' / 990.02' S= 0.0080 '/' Cc= 0.900 n= 0.010 PVC, smooth interior, Flow Area= 0.35 sf Primary OutFlow Max=2.07 cfs @ 15.38 hrs HW=997.39' TW=974.48' (Dynamic Tailwater) 1=Culvert (Barrel Controls 2.07 cfs @ 5.94 fps) EDRN MSE 24-hr 3 100-Year Rainfall=7.38"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 84HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Pond 1P: EXISTING POND Inflow Primary Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)130 120 110 100 90 80 70 60 50 40 30 20 10 0 Inflow Area=14.976 ac Peak Elev=997.39' Storage=226,085 cf 8.0" Round Culvert n=0.010 L=324.0' S=0.0080 '/' 123.52 cfs 2.07 cfs EDRN MSE 24-hr 3 100-Year Rainfall=7.38"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 85HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Pond 2P: West Ditch Inflow Area = 3.022 ac, 9.18% Impervious, Inflow Depth = 5.16" for 100-Year event Inflow = 23.82 cfs @ 12.16 hrs, Volume= 1.299 af Outflow = 18.98 cfs @ 12.22 hrs, Volume= 1.299 af, Atten= 20%, Lag= 3.7 min Primary = 14.00 cfs @ 12.22 hrs, Volume= 1.265 af Routed to Pond 10P : West Exisitng Wetland Secondary = 4.98 cfs @ 12.22 hrs, Volume= 0.035 af Routed to Pond 10P : West Exisitng Wetland Routing by Dyn-Stor-Ind method, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs Peak Elev= 998.80' @ 12.22 hrs Surf.Area= 4,536 sf Storage= 4,751 cf Plug-Flow detention time= (not calculated: outflow precedes inflow) Center-of-Mass det. time= 1.4 min ( 787.7 - 786.3 ) Volume Invert Avail.Storage Storage Description #1 995.00' 5,727 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 995.00 5 0 0 996.00 59 32 32 997.00 825 442 474 998.00 2,243 1,534 2,008 998.60 4,093 1,901 3,909 999.00 5,000 1,819 5,727 Device Routing Invert Outlet Devices #1 Primary 994.57'18.0" Round CMP_Round 18" L= 57.1' CMP, mitered to conform to fill, Ke= 0.700 Inlet / Outlet Invert= 994.57' / 989.52' S= 0.0884 '/' Cc= 0.900 n= 0.025 Corrugated metal, Flow Area= 1.77 sf #2 Secondary 998.59'20.0' long x 16.0' breadth Existing Berm Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 Coef. (English) 2.68 2.70 2.70 2.64 2.63 2.64 2.64 2.63 Primary OutFlow Max=13.99 cfs @ 12.22 hrs HW=998.79' TW=974.65' (Dynamic Tailwater) 1=CMP_Round 18" (Inlet Controls 13.99 cfs @ 7.92 fps) Secondary OutFlow Max=4.94 cfs @ 12.22 hrs HW=998.79' TW=974.65' (Dynamic Tailwater) 2=Existing Berm (Weir Controls 4.94 cfs @ 1.21 fps) EDRN MSE 24-hr 3 100-Year Rainfall=7.38"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 86HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Pond 2P: West Ditch Inflow Outflow Primary Secondary Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)26 24 22 20 18 16 14 12 10 8 6 4 2 0 Inflow Area=3.022 ac Peak Elev=998.80' Storage=4,751 cf 23.82 cfs 18.98 cfs 14.00 cfs 4.98 cfs EDRN MSE 24-hr 3 100-Year Rainfall=7.38"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 87HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Pond 10P: West Exisitng Wetland Inflow Area = 18.789 ac, 18.40% Impervious, Inflow Depth = 5.40" for 100-Year event Inflow = 24.07 cfs @ 12.22 hrs, Volume= 8.461 af Outflow = 7.35 cfs @ 12.55 hrs, Volume= 8.460 af, Atten= 69%, Lag= 20.1 min Primary = 7.35 cfs @ 12.55 hrs, Volume= 8.460 af Routed to Link 7L : TOTAL Routing by Dyn-Stor-Ind method, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs Starting Elev= 974.10' Surf.Area= 54,326 sf Storage= 5,411 cf Peak Elev= 974.85' @ 12.55 hrs Surf.Area= 57,558 sf Storage= 47,132 cf (41,721 cf above start) Plug-Flow detention time= 202.8 min calculated for 8.336 af (99% of inflow) Center-of-Mass det. time= 125.0 min ( 1,866.1 - 1,741.1 ) Volume Invert Avail.Storage Storage Description #1 974.00' 487,616 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 974.00 53,893 0 0 975.00 58,226 56,060 56,060 976.00 62,886 60,556 116,616 977.00 67,093 64,990 181,605 978.00 71,582 69,338 250,943 979.00 76,083 73,833 324,775 980.00 81,311 78,697 403,472 981.00 86,977 84,144 487,616 Device Routing Invert Outlet Devices #1 Primary 974.10'18.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads Primary OutFlow Max=7.35 cfs @ 12.55 hrs HW=974.85' TW=0.00' (Dynamic Tailwater) 1=Orifice/Grate (Orifice Controls 7.35 cfs @ 4.16 fps) EDRN MSE 24-hr 3 100-Year Rainfall=7.38"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 88HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Pond 10P: West Exisitng Wetland Inflow Primary Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)26 24 22 20 18 16 14 12 10 8 6 4 2 0 Inflow Area=18.789 ac Peak Elev=974.85' Storage=47,132 cf 24.07 cfs 7.35 cfs EDRN MSE 24-hr 3 100-Year Rainfall=7.38"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 89HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Link 3L: SOUTH Inflow Area = 2.310 ac, 1.72% Impervious, Inflow Depth = 5.08" for 100-Year event Inflow = 20.13 cfs @ 12.13 hrs, Volume= 0.978 af Primary = 20.13 cfs @ 12.13 hrs, Volume= 0.978 af, Atten= 0%, Lag= 0.0 min Routed to Link 7L : TOTAL Primary outflow = Inflow, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs Link 3L: SOUTH Inflow Primary Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Inflow Area=2.310 ac 20.13 cfs 20.13 cfs EDRN MSE 24-hr 3 100-Year Rainfall=7.38"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 90HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Link 5L: NORTHEAST Inflow Area = 2.076 ac, 24.16% Impervious, Inflow Depth = 5.53" for 100-Year event Inflow = 16.45 cfs @ 12.15 hrs, Volume= 0.956 af Primary = 16.45 cfs @ 12.15 hrs, Volume= 0.956 af, Atten= 0%, Lag= 0.0 min Routed to Link 7L : TOTAL Primary outflow = Inflow, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs Link 5L: NORTHEAST Inflow Primary Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Inflow Area=2.076 ac 16.45 cfs 16.45 cfs EDRN MSE 24-hr 3 100-Year Rainfall=7.38"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 91HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Link 6L: EAST Inflow Area = 0.260 ac, 0.00% Impervious, Inflow Depth = 4.93" for 100-Year event Inflow = 2.53 cfs @ 12.11 hrs, Volume= 0.107 af Primary = 2.53 cfs @ 12.11 hrs, Volume= 0.107 af, Atten= 0%, Lag= 0.0 min Routed to Link 7L : TOTAL Primary outflow = Inflow, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs Link 6L: EAST Inflow Primary Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)2 1 0 Inflow Area=0.260 ac 2.53 cfs 2.53 cfs EDRN MSE 24-hr 3 100-Year Rainfall=7.38"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 92HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Link 7L: TOTAL Inflow Area = 24.133 ac, 17.42% Impervious, Inflow Depth = 5.39" for 100-Year event Inflow = 45.65 cfs @ 12.13 hrs, Volume= 10.831 af Primary = 45.65 cfs @ 12.13 hrs, Volume= 10.831 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs Link 7L: TOTAL Inflow Primary Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)50 45 40 35 30 25 20 15 10 5 0 Inflow Area=24.133 ac 45.65 cfs 45.65 cfs EDRN MSE 24-hr 3 100-Year Rainfall=7.38"EDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc Page 93HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC Summary for Link 8L: Existing to NORTHWEST Inflow Area = 0.699 ac, 29.47% Impervious, Inflow Depth = 5.66" for 100-Year event Inflow = 7.66 cfs @ 12.09 hrs, Volume= 0.330 af Primary = 7.66 cfs @ 12.09 hrs, Volume= 0.330 af, Atten= 0%, Lag= 0.0 min Routed to Link 7L : TOTAL Primary outflow = Inflow, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs Link 8L: Existing to NORTHWEST Inflow Primary Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)8 7 6 5 4 3 2 1 0 Inflow Area=0.699 ac 7.66 cfs 7.66 cfs EDRN Table of ContentsEDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC TABLE OF CONTENTS Project Reports 1 Routing Diagram 2 Area Listing (all nodes) 3 Soil Listing (all nodes) 2-Year Event 4 Node Listing 6 Subcat E1: E1 7 Subcat E2: E2 8 Subcat E3: E3 9 Subcat E4: E4 10 Subcat E5: E5 11 Subcat E6: E6 12 Subcat E7: E7 13 Subcat E8: E8 14 Subcat OFF-1: OFF-1 15 Subcat OFF-2: OFF-2 16 Subcat OFF-3: OFF-3 17 Subcat OFF-4: OFF-4 18 Subcat OFF-5: OFF-5 19 Subcat OFF-6: OFF-6 20 Subcat OFF-7: OFF-7 21 Subcat OFF-8: OFF-8 22 Subcat OFF-9: OFF-9 23 Pond 1P: EXISTING POND 25 Pond 2P: West Ditch 27 Pond 10P: West Exisitng Wetland 29 Link 3L: SOUTH 30 Link 5L: NORTHEAST 31 Link 6L: EAST 32 Link 7L: TOTAL 33 Link 8L: Existing to NORTHWEST 10-Year Event 34 Node Listing 36 Subcat E1: E1 37 Subcat E2: E2 38 Subcat E3: E3 39 Subcat E4: E4 40 Subcat E5: E5 41 Subcat E6: E6 42 Subcat E7: E7 43 Subcat E8: E8 44 Subcat OFF-1: OFF-1 45 Subcat OFF-2: OFF-2 EDRN Table of ContentsEDRN Printed 6/4/2025Prepared by Alliant Engineering, Inc HydroCAD® 10.20-7a s/n 01427 © 2025 HydroCAD Software Solutions LLC 46 Subcat OFF-3: OFF-3 47 Subcat OFF-4: OFF-4 48 Subcat OFF-5: OFF-5 49 Subcat OFF-6: OFF-6 50 Subcat OFF-7: OFF-7 51 Subcat OFF-8: OFF-8 52 Subcat OFF-9: OFF-9 53 Pond 1P: EXISTING POND 55 Pond 2P: West Ditch 57 Pond 10P: West Exisitng Wetland 59 Link 3L: SOUTH 60 Link 5L: NORTHEAST 61 Link 6L: EAST 62 Link 7L: TOTAL 63 Link 8L: Existing to NORTHWEST 100-Year Event 64 Node Listing 66 Subcat E1: E1 67 Subcat E2: E2 68 Subcat E3: E3 69 Subcat E4: E4 70 Subcat E5: E5 71 Subcat E6: E6 72 Subcat E7: E7 73 Subcat E8: E8 74 Subcat OFF-1: OFF-1 75 Subcat OFF-2: OFF-2 76 Subcat OFF-3: OFF-3 77 Subcat OFF-4: OFF-4 78 Subcat OFF-5: OFF-5 79 Subcat OFF-6: OFF-6 80 Subcat OFF-7: OFF-7 81 Subcat OFF-8: OFF-8 82 Subcat OFF-9: OFF-9 83 Pond 1P: EXISTING POND 85 Pond 2P: West Ditch 87 Pond 10P: West Exisitng Wetland 89 Link 3L: SOUTH 90 Link 5L: NORTHEAST 91 Link 6L: EAST 92 Link 7L: TOTAL 93 Link 8L: Existing to NORTHWEST 176181353637909192939495969798991001011021031041051061071081091101111121131141151161171181191201211221231251261271281291301311321331341351361371381391401411431441451461471481491501511521531551641651661671681721731741751771781791801821831841851861871881891901911921931941951961971981992003013023033043053063073083093103113123133143153163173183193203213223233243253263273283293303313323333343353363373383393403413423433443453463473483493503513523533543553563573583593603613623633643653663673683693703713723733743753763773783793803813823833843853863873883893903913923933943953963973983994004014024034044054064074534544554564574591628162916331634163516361637164116421643164416451646164716481649165016511652165316541655165616571658165916601664166516661667166816691670167116731674167516761677167816791680168116821683168416851686168716881689169016911692169316941695169616971698169917001701170217031704170517061707170817091710171117121713171417151716171717181719172017231724172517261727172817291730173117321733173417351736173817391740174317441745174617471759176017621770177117721773177417751776177717841785178617871788178917901791179217931794179517961797179817991800180118111812181318141815181618171818181918201821182218231824182518261827182818291830183118321833183418351836183718381839184018411842184318471848185118521853185418551856185718581859186018611862187318741875187618771878187918801881192119221923192419251926192719281929193019311932193619371938193919401941194219491950195112375123456789101112136BLOCK 2BLOCK 2BLOCK 1BLOCK 1STORMWATER WETLAND/FILTRATIONNWL:994.0100 YEAR HWL:999.57PEACEFUL LANE PEACEFUL LANE 4NEZ PERCE DRIVEPEACEFUL LANE FILTRATION BASIN 2100 YEAR HWL:997.98FILTRATION TRENCH100 YEAR HWL:1020.10GU File Location: X:\4000320-00\001\40 Design\45 Stormwater\HYDRO-PRO.dwg Plotted By: Mark Rausch on June 4, 2025 at 7:52:14 PMKnow what's below.Call before you dig.RDial 811FOR REV IEW ONLYPRELIM INARYNOT FOR CONSTRUCT ION0SCALE IN FEET3570140NWSEPRELIMINARY PLAT CITY SUBMITTAL FINAL PLAT - CITY SUBMITTAL 4-18-2025 12-19-2024 11CHANHASSEN, MN PLEASANT VIEW POINTE PROPOSED DRAINAGE MAP www.alliant-inc.comPROJECT TEAM DATAQA/QC CHECKDateByCERTIFICATIONDateLicense no.DATE DESCRIPTION Project No.:Drafted By:Designed By:Sheetof TAS I hereby certify that this plan, specification, or reportwas prepared by me or under my direct supervisionand that I am a duly LicensedProfessional Engineer under the laws of theState of MN. 11LEGEND 9S S9 OFF-1 OFF-1 OFF-2 OFF-2 OFF-3 OFF-3 OFF-4 OFF-4 OFF-5 OFF-5 OFF-6 OFF-6 OFF-7 OFF-7 OFF-8 OFF-8 OFF-9 OFF-9 S1 S1 S2 S2 S3 S3 S4 S4 S5 S5 S6 S6 S7 S7 S8 S8 9R (new Reach) 10R (new Reach)1P FILTRATION/WETLAND 8P West Filtration Basin 9P South Filtration Trench 10P West Existing Wetland 3L SOUTH 6L EAST 7L TOTAL 8L Interim condition Link Routing Diagram for PDRN Prepared by Alliant Engineering, Inc, Printed 7/3/2025 HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Subcat Reach Pond Link PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 2HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Project Notes PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 3HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Rainfall Events Listing (selected events) Event# Event Name Storm Type Curve Mode Duration (hours) B/B Depth (inches) AMC 1 2-Year MSE 24-hr 3 Default 24.00 1 2.87 2 2 10-Year MSE 24-hr 3 Default 24.00 1 4.26 2 3 100-Year MSE 24-hr 3 Default 24.00 1 7.38 2 PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 4HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Area Listing (all nodes) Area (acres) CN Description (subcatchment-numbers) 8.275 80 >75% Grass cover, Good, HSG D (9S, OFF-4, OFF-6, OFF-7, OFF-8, OFF-9, S1, S2, S8) 0.040 98 Impervious, HSG D (OFF-6) 0.911 98 Paved parking, HSG C (OFF-3, OFF-4) 5.065 98 Paved parking, HSG D (OFF-1, OFF-8, OFF-9, S2) 0.092 98 Unconnected roofs, HSG C (OFF-2) 1.927 98 Unconnected roofs, HSG D (9S, OFF-7, S1, S4, S5) 1.043 98 Water Surface, HSG D (994) (S1) 0.676 82 Woods/grass comb., Fair, HSG D (OFF-5, S5, S7) 6.108 79 Woods/grass comb., Good, HSG D (OFF-1, OFF-2, OFF-3, S3, S4, S6) 24.137 87 TOTAL AREA PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 5HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Soil Listing (all nodes) Area (acres) Soil Group Subcatchment Numbers 0.000 HSG A 0.000 HSG B 1.003 HSG C OFF-2, OFF-3, OFF-4 23.135 HSG D 9S, OFF-1, OFF-2, OFF-3, OFF-4, OFF-5, OFF-6, OFF-7, OFF-8, OFF-9, S1, S2, S3, S4, S5, S6, S7, S8 0.000 Other 24.137 TOTAL AREA PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 6HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Ground Covers (all 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 0.000 8.275 0.000 8.275 >75% Grass cover, Good 9S, OFF-4, OFF-6, OFF-7, OFF-8, OFF-9, S1, S2, S8 0.000 0.000 0.000 0.040 0.000 0.040 Impervious OFF-6 0.000 0.000 0.911 5.065 0.000 5.976 Paved parking OFF-1, OFF-3, OFF-4, OFF-8, OFF-9, S2 0.000 0.000 0.092 1.927 0.000 2.019 Unconnected roofs 9S, OFF-2, OFF-7, S1, S4, S5 0.000 0.000 0.000 1.043 0.000 1.043 Water Surface S1 0.000 0.000 0.000 0.676 0.000 0.676 Woods/grass comb., Fair OFF-5, S5, S7 0.000 0.000 0.000 6.108 0.000 6.108 Woods/grass comb., Good OFF-1, OFF-2, OFF-3, S3, S4, S6 0.000 0.000 1.003 23.135 0.000 24.137 TOTAL AREA MSE 24-hr 3 2-Year Rainfall=2.87"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 7HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Time span=0.00-600.00 hrs, dt=0.01 hrs, 60001 points Runoff by SCS TR-20 method, UH=SCS, Weighted-Q Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method Peak Elev=995.96' Storage=181,131 cf Inflow=41.52 cfs 2.838 afPond 1P: FILTRATION/WETLAND Outflow=0.94 cfs 2.801 af Peak Elev=996.52' Storage=5,365 cf Inflow=6.39 cfs 0.362 afPond 8P: West Filtration Basin Primary=8.24 cfs 0.199 af Secondary=0.04 cfs 0.163 af Outflow=8.28 cfs 0.362 af Peak Elev=1,020.04' Storage=2,185 cf Inflow=2.83 cfs 0.162 afPond 9P: South Filtration Trench Primary=0.05 cfs 0.078 af Secondary=2.71 cfs 0.075 af Outflow=2.76 cfs 0.154 af Peak Elev=974.27' Storage=14,642 cf Inflow=8.34 cfs 3.188 afPond 10P: West Existing Wetland Outflow=1.07 cfs 3.184 af MSE 24-hr 3 2-Year Rainfall=2.87"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 8HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Summary for Pond 1P: FILTRATION/WETLAND Inflow Area = 19.209 ac, 42.35% Impervious, Inflow Depth = 1.77" for 2-Year event Inflow = 41.52 cfs @ 12.18 hrs, Volume= 2.838 af Outflow = 0.94 cfs @ 15.38 hrs, Volume= 2.801 af, Atten= 98%, Lag= 192.0 min Primary = 0.94 cfs @ 15.38 hrs, Volume= 2.801 af Routed to Reach 9R : (new Reach) Routing by Dyn-Stor-Ind method, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs Starting Elev= 994.00' Surf.Area= 77,114 sf Storage= 83,771 cf Peak Elev= 995.96' @ 15.38 hrs Surf.Area= 84,683 sf Storage= 181,131 cf (97,360 cf above start) Plug-Flow detention time= 13,246.2 min calculated for 0.878 af (31% of inflow) Center-of-Mass det. time= 4,896.9 min ( 5,679.9 - 783.0 ) Volume Invert Avail.Storage Storage Description #1 990.00' 16,422 cf West Forebay (Prismatic) Listed below (Recalc) #2 993.50' 1,015 cf West shallow wetland (Prismatic) Listed below (Recalc) #3 990.00' 18,942 cf Remnant Wetland (Prismatic) Listed below (Recalc) #4 989.00' 39,571 cf Middle Forebay (Prismatic) Listed below (Recalc) #5 993.50' 665 cf East shallow wetland (Prismatic) Listed below (Recalc) #6 992.00' 7,157 cf Filtration (Prismatic) Listed below (Recalc) -Impervious 23,856 cf Overall x 30.0% Voids #7 994.00' 336,285 cf Live Storage (Prismatic) Listed below (Recalc) 420,056 cf Total Available Storage Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 990.00 2,339 0 0 992.00 4,014 6,353 6,353 994.00 6,055 10,069 16,422 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 993.50 1,499 0 0 994.00 2,561 1,015 1,015 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 990.00 1,596 0 0 992.00 4,761 6,357 6,357 994.00 7,824 12,585 18,942 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 989.00 4,875 0 0 990.00 5,864 5,370 5,370 991.00 6,954 6,409 11,779 993.00 9,401 16,355 28,134 994.00 13,473 11,437 39,571 MSE 24-hr 3 2-Year Rainfall=2.87"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 9HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 993.50 961 0 0 994.00 1,698 665 665 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 992.00 11,928 0 0 994.00 11,928 23,856 23,856 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 994.00 45,503 0 0 995.00 49,888 47,696 47,696 996.00 53,188 51,538 99,234 998.00 56,729 109,917 209,151 1,000.00 70,405 127,134 336,285 Device Routing Invert Outlet Devices #1 Primary 990.90'15.0" Round Culvert L= 527.0' RCP, square edge headwall, Ke= 0.500 Inlet / Outlet Invert= 990.90' / 988.26' S= 0.0050 '/' Cc= 0.900 n= 0.013 Concrete sewer w/manholes & inlets, Flow Area= 1.23 sf #2 Device 1 999.10'6.0' long x 0.5' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 Coef. (English) 2.80 2.92 3.08 3.30 3.32 #3 Device 1 994.00'0.800 in/hr Filtration over Surface area above 994.00' Excluded Surface area = 77,114 sf #4 Device 1 995.00'6.0" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads Primary OutFlow Max=0.94 cfs @ 15.38 hrs HW=995.96' TW=986.56' (Dynamic Tailwater) 1=Culvert (Passes 0.94 cfs of 6.74 cfs potential flow) 2=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) 3=Filtration (Exfiltration Controls 0.14 cfs) 4=Orifice/Grate (Orifice Controls 0.80 cfs @ 4.07 fps) MSE 24-hr 3 2-Year Rainfall=2.87"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 10HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Pond 1P: FILTRATION/WETLAND Inflow Primary Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)46 44 42 40 38 36 34 32 30 28 26 24 22 20 18 16 14 12 10 8 6 4 2 0 Inflow Area=19.209 ac Peak Elev=995.96' Storage=181,131 cf 41.52 cfs 0.94 cfs MSE 24-hr 3 2-Year Rainfall=2.87"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 11HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Hydrograph for Pond 1P: FILTRATION/WETLAND Time (hours) Inflow (cfs) Storage (cubic-feet) Elevation (feet) Primary (cfs) 0.00 0.00 83,771 994.00 0.00 20.00 0.50 177,567 995.90 0.90 40.00 0.00 142,280 995.22 0.22 60.00 0.00 132,966 995.03 0.09 80.00 0.00 127,273 994.92 0.07 100.00 0.00 122,225 994.81 0.07 120.00 0.00 117,743 994.72 0.06 140.00 0.00 113,769 994.64 0.05 160.00 0.00 110,248 994.57 0.05 180.00 0.00 107,130 994.50 0.04 200.00 0.00 104,372 994.44 0.04 220.00 0.00 101,934 994.39 0.03 240.00 0.00 99,780 994.35 0.03 260.00 0.00 97,878 994.31 0.02 280.00 0.00 96,198 994.27 0.02 300.00 0.00 94,717 994.24 0.02 320.00 0.00 93,410 994.21 0.02 340.00 0.00 92,258 994.18 0.02 360.00 0.00 91,243 994.16 0.01 380.00 0.00 90,348 994.14 0.01 400.00 0.00 89,560 994.13 0.01 420.00 0.00 88,866 994.11 0.01 440.00 0.00 88,254 994.10 0.01 460.00 0.00 87,716 994.09 0.01 480.00 0.00 87,242 994.08 0.01 500.00 0.00 86,825 994.07 0.01 520.00 0.00 86,458 994.06 0.00 540.00 0.00 86,134 994.05 0.00 560.00 0.00 85,850 994.05 0.00 580.00 0.00 85,600 994.04 0.00 600.00 0.00 85,380 994.04 0.00 MSE 24-hr 3 2-Year Rainfall=2.87"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 12HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Stage-Area-Storage for Pond 1P: FILTRATION/WETLAND Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 989.00 4,875 0 989.20 5,073 995 989.40 5,271 2,029 989.60 5,468 3,103 989.80 5,666 4,216 990.00 9,799 5,370 990.20 10,501 7,400 990.40 11,203 9,570 990.60 11,905 11,881 990.80 12,607 14,332 991.00 13,309 16,924 991.20 14,038 19,658 991.40 14,766 22,539 991.60 15,495 25,565 991.80 16,224 28,737 992.00 16,953 32,054 992.20 17,708 36,236 992.40 18,463 40,569 992.60 19,218 45,052 992.80 19,973 49,687 993.00 20,728 54,473 993.20 22,053 59,467 993.40 23,378 64,725 993.60 27,522 70,513 993.80 29,567 76,938 994.00 77,114 83,771 994.20 77,991 92,959 994.40 78,868 102,323 994.60 79,745 111,862 994.80 80,622 121,577 995.00 81,499 131,467 995.20 82,159 141,510 995.40 82,819 151,686 995.60 83,479 161,993 995.80 84,139 172,433 996.00 84,799 183,005 996.20 85,153 193,678 996.40 85,507 204,421 996.60 85,861 215,236 996.80 86,215 226,122 997.00 86,570 237,078 997.20 86,924 248,105 997.40 87,278 259,203 997.60 87,632 270,372 997.80 87,986 281,611 998.00 88,340 292,922 998.20 89,708 304,404 998.40 91,075 316,160 998.60 92,443 328,190 998.80 93,810 340,493 999.00 95,178 353,070 999.20 96,546 365,920 Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 999.40 97,913 379,043 999.60 99,281 392,441 999.80 100,648 406,111 1,000.00 102,016 420,056 MSE 24-hr 3 2-Year Rainfall=2.87"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 13HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Summary for Pond 8P: West Filtration Basin [90] Warning: Qout>Qin may require smaller dt or Finer Routing Inflow Area = 2.967 ac, 23.03% Impervious, Inflow Depth = 1.46" for 2-Year event Inflow = 6.39 cfs @ 12.18 hrs, Volume= 0.362 af Outflow = 8.28 cfs @ 12.19 hrs, Volume= 0.362 af, Atten= 0%, Lag= 1.1 min Primary = 8.24 cfs @ 12.19 hrs, Volume= 0.199 af Routed to Reach 9R : (new Reach) Secondary = 0.04 cfs @ 12.19 hrs, Volume= 0.163 af Routed to Reach 9R : (new Reach) Routing by Dyn-Stor-Ind method, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs Peak Elev= 996.52' @ 12.19 hrs Surf.Area= 4,455 sf Storage= 5,365 cf Plug-Flow detention time= 896.5 min calculated for 0.362 af (100% of inflow) Center-of-Mass det. time= 896.4 min ( 1,692.5 - 796.1 ) Volume Invert Avail.Storage Storage Description #1 995.00' 16,956 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 995.00 2,655 0 0 996.00 3,804 3,230 3,230 996.50 4,432 2,059 5,289 997.00 5,109 2,385 7,674 998.00 6,579 5,844 13,518 998.50 7,173 3,438 16,956 Device Routing Invert Outlet Devices #1 Secondary 995.00'1.000 in/hr Filtration over Surface area above 995.00' Excluded Surface area = 2,655 sf #2 Primary 992.00'15.0" Round Culvert L= 22.0' RCP, mitered to conform to fill, Ke= 0.700 Inlet / Outlet Invert= 992.00' / 991.00' S= 0.0455 '/' Cc= 0.900 n= 0.013, Flow Area= 1.23 sf #3 Device 2 996.50'48.0" Horiz. Orifice/Grate C= 0.600 Primary OutFlow Max=7.34 cfs @ 12.19 hrs HW=996.51' TW=986.81' (Dynamic Tailwater) 2=Culvert (Passes 7.34 cfs of 10.28 cfs potential flow) 3=Orifice/Grate (Orifice Controls 7.34 cfs @ 0.58 fps) Secondary OutFlow Max=0.04 cfs @ 12.19 hrs HW=996.52' TW=986.81' (Dynamic Tailwater) 1=Filtration (Exfiltration Controls 0.04 cfs) MSE 24-hr 3 2-Year Rainfall=2.87"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 14HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Pond 8P: West Filtration Basin Inflow Outflow Primary Secondary Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)9 8 7 6 5 4 3 2 1 0 Inflow Area=2.967 ac Peak Elev=996.52' Storage=5,365 cf 6.39 cfs 8.28 cfs 8.24 cfs 0.04 cfs MSE 24-hr 3 2-Year Rainfall=2.87"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 15HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Hydrograph for Pond 8P: West Filtration Basin Time (hours) Inflow (cfs) Storage (cubic-feet) Elevation (feet) Outflow (cfs) Primary (cfs) Secondary (cfs) 0.00 0.00 0 995.00 0.00 0.00 0.00 20.00 0.07 5,289 996.50 0.07 0.03 0.04 40.00 0.00 3,297 996.02 0.03 0.00 0.03 60.00 0.00 1,781 995.59 0.02 0.00 0.02 80.00 0.00 922 995.32 0.01 0.00 0.01 100.00 0.00 465 995.17 0.00 0.00 0.00 120.00 0.00 230 995.09 0.00 0.00 0.00 140.00 0.00 113 995.04 0.00 0.00 0.00 160.00 0.00 55 995.02 0.00 0.00 0.00 180.00 0.00 27 995.01 0.00 0.00 0.00 200.00 0.00 13 995.00 0.00 0.00 0.00 220.00 0.00 6 995.00 0.00 0.00 0.00 240.00 0.00 3 995.00 0.00 0.00 0.00 260.00 0.00 2 995.00 0.00 0.00 0.00 280.00 0.00 1 995.00 0.00 0.00 0.00 300.00 0.00 0 995.00 0.00 0.00 0.00 320.00 0.00 0 995.00 0.00 0.00 0.00 340.00 0.00 0 995.00 0.00 0.00 0.00 360.00 0.00 0 995.00 0.00 0.00 0.00 380.00 0.00 0 995.00 0.00 0.00 0.00 400.00 0.00 0 995.00 0.00 0.00 0.00 420.00 0.00 0 995.00 0.00 0.00 0.00 440.00 0.00 0 995.00 0.00 0.00 0.00 460.00 0.00 0 995.00 0.00 0.00 0.00 480.00 0.00 0 995.00 0.00 0.00 0.00 500.00 0.00 0 995.00 0.00 0.00 0.00 520.00 0.00 0 995.00 0.00 0.00 0.00 540.00 0.00 0 995.00 0.00 0.00 0.00 560.00 0.00 0 995.00 0.00 0.00 0.00 580.00 0.00 0 995.00 0.00 0.00 0.00 600.00 0.00 0 995.00 0.00 0.00 0.00 MSE 24-hr 3 2-Year Rainfall=2.87"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 16HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Stage-Area-Storage for Pond 8P: West Filtration Basin Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 995.00 2,655 0 995.05 2,712 134 995.10 2,770 271 995.15 2,827 411 995.20 2,885 554 995.25 2,942 700 995.30 3,000 848 995.35 3,057 1,000 995.40 3,115 1,154 995.45 3,172 1,311 995.50 3,230 1,471 995.55 3,287 1,634 995.60 3,344 1,800 995.65 3,402 1,968 995.70 3,459 2,140 995.75 3,517 2,314 995.80 3,574 2,492 995.85 3,632 2,672 995.90 3,689 2,855 995.95 3,747 3,041 996.00 3,804 3,230 996.05 3,867 3,421 996.10 3,930 3,616 996.15 3,992 3,814 996.20 4,055 4,015 996.25 4,118 4,220 996.30 4,181 4,427 996.35 4,244 4,638 996.40 4,306 4,852 996.45 4,369 5,068 996.50 4,432 5,289 996.55 4,500 5,512 996.60 4,567 5,738 996.65 4,635 5,969 996.70 4,703 6,202 996.75 4,771 6,439 996.80 4,838 6,679 996.85 4,906 6,923 996.90 4,974 7,170 996.95 5,041 7,420 997.00 5,109 7,674 997.05 5,182 7,931 997.10 5,256 8,192 997.15 5,329 8,457 997.20 5,403 8,725 997.25 5,477 8,997 997.30 5,550 9,273 997.35 5,624 9,552 997.40 5,697 9,835 997.45 5,771 10,122 997.50 5,844 10,412 997.55 5,917 10,706 Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 997.60 5,991 11,004 997.65 6,064 11,305 997.70 6,138 11,610 997.75 6,212 11,919 997.80 6,285 12,231 997.85 6,359 12,547 997.90 6,432 12,867 997.95 6,506 13,191 998.00 6,579 13,518 998.05 6,638 13,848 998.10 6,698 14,182 998.15 6,757 14,518 998.20 6,817 14,857 998.25 6,876 15,200 998.30 6,935 15,545 998.35 6,995 15,893 998.40 7,054 16,244 998.45 7,114 16,599 998.50 7,173 16,956 MSE 24-hr 3 2-Year Rainfall=2.87"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 17HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Summary for Pond 9P: South Filtration Trench Inflow Area = 1.353 ac, 19.13% Impervious, Inflow Depth = 1.44" for 2-Year event Inflow = 2.83 cfs @ 12.17 hrs, Volume= 0.162 af Outflow = 2.76 cfs @ 12.19 hrs, Volume= 0.154 af, Atten= 3%, Lag= 1.4 min Primary = 0.05 cfs @ 12.19 hrs, Volume= 0.078 af Routed to Link 3L : SOUTH Secondary = 2.71 cfs @ 12.19 hrs, Volume= 0.075 af Routed to Link 3L : SOUTH Routing by Dyn-Stor-Ind method, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs Peak Elev= 1,020.04' @ 12.19 hrs Surf.Area= 3,474 sf Storage= 2,185 cf Plug-Flow detention time= 284.7 min calculated for 0.154 af (95% of inflow) Center-of-Mass det. time= 258.3 min ( 1,057.8 - 799.5 ) Volume Invert Avail.Storage Storage Description #1 1,017.25' 368 cf Filter Storage (Min) (Prismatic) Listed below (Recalc) 1,050 cf Overall x 35.0% Voids #2 1,019.00' 3,345 cf Live Storage (Prismatic) Listed below (Recalc) 3,712 cf Total Available Storage Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 1,017.25 600 0 0 1,019.00 600 1,050 1,050 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 1,019.00 600 0 0 1,019.50 1,714 579 579 1,020.00 2,800 1,129 1,707 1,020.50 3,750 1,638 3,345 Device Routing Invert Outlet Devices #1 Primary 1,015.00'12.0" Round Culvert L= 200.0' RCP, square edge headwall, Ke= 0.500 Inlet / Outlet Invert= 1,015.00' / 1,000.00' S= 0.0750 '/' Cc= 0.900 n= 0.013 Concrete pipe, bends & connections, Flow Area= 0.79 sf #2 Device 1 1,019.00'1.000 in/hr Filtration over Surface area above 1,019.00' Excluded Surface area = 1,200 sf #3 Secondary 1,020.00'130.0' long + 3.0 '/' SideZ x 1.0' 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 Coef. (English) 2.69 2.72 2.75 2.85 2.98 3.08 3.20 3.28 3.31 3.30 3.31 3.32 MSE 24-hr 3 2-Year Rainfall=2.87"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 18HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Primary OutFlow Max=0.05 cfs @ 12.19 hrs HW=1,020.04' TW=0.00' (Dynamic Tailwater) 1=Culvert (Passes 0.05 cfs of 8.06 cfs potential flow) 2=Filtration (Exfiltration Controls 0.05 cfs) Secondary OutFlow Max=2.68 cfs @ 12.19 hrs HW=1,020.04' TW=0.00' (Dynamic Tailwater) 3=Broad-Crested Rectangular Weir (Weir Controls 2.68 cfs @ 0.53 fps) Pond 9P: South Filtration Trench Inflow Outflow Primary Secondary Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)3 2 1 0 Inflow Area=1.353 ac Peak Elev=1,020.04' Storage=2,185 cf 2.83 cfs 2.76 cfs 0.05 cfs 2.71 cfs MSE 24-hr 3 2-Year Rainfall=2.87"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 19HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Hydrograph for Pond 9P: South Filtration Trench Time (hours) Inflow (cfs) Storage (cubic-feet) Elevation (feet) Outflow (cfs) Primary (cfs) Secondary (cfs) 0.00 0.00 0 1,017.25 0.00 0.00 0.00 20.00 0.03 1,980 1,019.97 0.05 0.05 0.00 40.00 0.00 431 1,019.09 0.00 0.00 0.00 60.00 0.00 368 1,019.00 0.00 0.00 0.00 80.00 0.00 368 1,019.00 0.00 0.00 0.00 100.00 0.00 368 1,019.00 0.00 0.00 0.00 120.00 0.00 368 1,019.00 0.00 0.00 0.00 140.00 0.00 368 1,019.00 0.00 0.00 0.00 160.00 0.00 368 1,019.00 0.00 0.00 0.00 180.00 0.00 368 1,019.00 0.00 0.00 0.00 200.00 0.00 368 1,019.00 0.00 0.00 0.00 220.00 0.00 368 1,019.00 0.00 0.00 0.00 240.00 0.00 368 1,019.00 0.00 0.00 0.00 260.00 0.00 368 1,019.00 0.00 0.00 0.00 280.00 0.00 368 1,019.00 0.00 0.00 0.00 300.00 0.00 368 1,019.00 0.00 0.00 0.00 320.00 0.00 368 1,019.00 0.00 0.00 0.00 340.00 0.00 368 1,019.00 0.00 0.00 0.00 360.00 0.00 368 1,019.00 0.00 0.00 0.00 380.00 0.00 368 1,019.00 0.00 0.00 0.00 400.00 0.00 368 1,019.00 0.00 0.00 0.00 420.00 0.00 368 1,019.00 0.00 0.00 0.00 440.00 0.00 368 1,019.00 0.00 0.00 0.00 460.00 0.00 368 1,019.00 0.00 0.00 0.00 480.00 0.00 368 1,019.00 0.00 0.00 0.00 500.00 0.00 368 1,019.00 0.00 0.00 0.00 520.00 0.00 368 1,019.00 0.00 0.00 0.00 540.00 0.00 368 1,019.00 0.00 0.00 0.00 560.00 0.00 368 1,019.00 0.00 0.00 0.00 580.00 0.00 368 1,019.00 0.00 0.00 0.00 600.00 0.00 368 1,019.00 0.00 0.00 0.00 MSE 24-hr 3 2-Year Rainfall=2.87"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 20HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Stage-Area-Storage for Pond 9P: South Filtration Trench Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 1,017.25 600 0 1,017.30 600 10 1,017.35 600 21 1,017.40 600 31 1,017.45 600 42 1,017.50 600 53 1,017.55 600 63 1,017.60 600 74 1,017.65 600 84 1,017.70 600 95 1,017.75 600 105 1,017.80 600 115 1,017.85 600 126 1,017.90 600 136 1,017.95 600 147 1,018.00 600 158 1,018.05 600 168 1,018.10 600 179 1,018.15 600 189 1,018.20 600 200 1,018.25 600 210 1,018.30 600 220 1,018.35 600 231 1,018.40 600 241 1,018.45 600 252 1,018.50 600 263 1,018.55 600 273 1,018.60 600 284 1,018.65 600 294 1,018.70 600 305 1,018.75 600 315 1,018.80 600 325 1,018.85 600 336 1,018.90 600 346 1,018.95 600 357 1,019.00 1,200 368 1,019.05 1,311 400 1,019.10 1,423 439 1,019.15 1,534 483 1,019.20 1,646 532 1,019.25 1,757 587 1,019.30 1,868 648 1,019.35 1,980 714 1,019.40 2,091 786 1,019.45 2,203 863 1,019.50 2,314 946 1,019.55 2,423 1,034 1,019.60 2,531 1,128 1,019.65 2,640 1,228 1,019.70 2,748 1,332 1,019.75 2,857 1,442 1,019.80 2,966 1,558 Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 1,019.85 3,074 1,679 1,019.90 3,183 1,805 1,019.95 3,291 1,937 1,020.00 3,400 2,075 1,020.05 3,495 2,217 1,020.10 3,590 2,364 1,020.15 3,685 2,516 1,020.20 3,780 2,673 1,020.25 3,875 2,834 1,020.30 3,970 3,000 1,020.35 4,065 3,171 1,020.40 4,160 3,346 1,020.45 4,255 3,527 1,020.50 4,350 3,712 MSE 24-hr 3 2-Year Rainfall=2.87"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 21HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Summary for Pond 10P: West Existing Wetland Inflow Area = 22.414 ac, 39.34% Impervious, Inflow Depth > 1.71" for 2-Year event Inflow = 8.34 cfs @ 12.20 hrs, Volume= 3.188 af Outflow = 1.07 cfs @ 16.08 hrs, Volume= 3.184 af, Atten= 87%, Lag= 232.7 min Primary = 1.07 cfs @ 16.08 hrs, Volume= 3.184 af Routed to Link 7L : TOTAL Routing by Dyn-Stor-Ind method, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs Starting Elev= 974.10' Surf.Area= 54,326 sf Storage= 5,411 cf Peak Elev= 974.27' @ 16.08 hrs Surf.Area= 55,058 sf Storage= 14,642 cf (9,231 cf above start) Plug-Flow detention time= 1,350.0 min calculated for 3.059 af (96% of inflow) Center-of-Mass det. time= 234.6 min ( 5,424.6 - 5,190.1 ) Volume Invert Avail.Storage Storage Description #1 974.00' 487,616 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 974.00 53,893 0 0 975.00 58,226 56,060 56,060 976.00 62,886 60,556 116,616 977.00 67,093 64,990 181,605 978.00 71,582 69,338 250,943 979.00 76,083 73,833 324,775 980.00 81,311 78,697 403,472 981.00 86,977 84,144 487,616 Device Routing Invert Outlet Devices #1 Primary 974.10'18.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads Primary OutFlow Max=1.07 cfs @ 16.08 hrs HW=974.27' TW=0.00' (Dynamic Tailwater) 1=Orifice/Grate (Weir Controls 1.07 cfs @ 1.34 fps) MSE 24-hr 3 2-Year Rainfall=2.87"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 22HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Pond 10P: West Existing Wetland Inflow Primary Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)9 8 7 6 5 4 3 2 1 0 Inflow Area=22.414 ac Peak Elev=974.27' Storage=14,642 cf 8.34 cfs 1.07 cfs MSE 24-hr 3 2-Year Rainfall=2.87"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 23HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Hydrograph for Pond 10P: West Existing Wetland Time (hours) Inflow (cfs) Storage (cubic-feet) Elevation (feet) Primary (cfs) 0.00 0.00 5,411 974.10 0.00 20.00 0.97 14,322 974.26 1.01 40.00 0.25 9,410 974.17 0.31 60.00 0.10 7,450 974.14 0.11 80.00 0.08 7,119 974.13 0.09 100.00 0.07 6,941 974.13 0.07 120.00 0.06 6,797 974.13 0.06 140.00 0.05 6,675 974.12 0.05 160.00 0.05 6,569 974.12 0.05 180.00 0.04 6,475 974.12 0.04 200.00 0.04 6,390 974.12 0.04 220.00 0.03 6,313 974.12 0.03 240.00 0.03 6,241 974.12 0.03 260.00 0.02 6,175 974.11 0.03 280.00 0.02 6,115 974.11 0.02 300.00 0.02 6,059 974.11 0.02 320.00 0.02 6,008 974.11 0.02 340.00 0.02 5,960 974.11 0.02 360.00 0.01 5,916 974.11 0.01 380.00 0.01 5,876 974.11 0.01 400.00 0.01 5,839 974.11 0.01 420.00 0.01 5,805 974.11 0.01 440.00 0.01 5,773 974.11 0.01 460.00 0.01 5,744 974.11 0.01 480.00 0.01 5,717 974.11 0.01 500.00 0.01 5,693 974.11 0.01 520.00 0.00 5,670 974.10 0.01 540.00 0.00 5,649 974.10 0.00 560.00 0.00 5,630 974.10 0.00 580.00 0.00 5,612 974.10 0.00 600.00 0.00 5,596 974.10 0.00 MSE 24-hr 3 2-Year Rainfall=2.87"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 24HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Stage-Area-Storage for Pond 10P: West Existing Wetland Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 974.00 53,893 0 974.10 54,326 5,411 974.20 54,760 10,865 974.30 55,193 16,363 974.40 55,626 21,904 974.50 56,060 27,488 974.60 56,493 33,116 974.70 56,926 38,787 974.80 57,359 44,501 974.90 57,793 50,259 975.00 58,226 56,060 975.10 58,692 61,905 975.20 59,158 67,798 975.30 59,624 73,737 975.40 60,090 79,723 975.50 60,556 85,755 975.60 61,022 91,834 975.70 61,488 97,959 975.80 61,954 104,131 975.90 62,420 110,350 976.00 62,886 116,616 976.10 63,307 122,925 976.20 63,727 129,277 976.30 64,148 135,671 976.40 64,569 142,106 976.50 64,990 148,584 976.60 65,410 155,104 976.70 65,831 161,666 976.80 66,252 168,271 976.90 66,672 174,917 977.00 67,093 181,605 977.10 67,542 188,337 977.20 67,991 195,113 977.30 68,440 201,935 977.40 68,889 208,801 977.50 69,338 215,713 977.60 69,786 222,669 977.70 70,235 229,670 977.80 70,684 236,716 977.90 71,133 243,807 978.00 71,582 250,943 978.10 72,032 258,123 978.20 72,482 265,349 978.30 72,932 272,620 978.40 73,382 279,935 978.50 73,833 287,296 978.60 74,283 294,702 978.70 74,733 302,153 978.80 75,183 309,648 978.90 75,633 317,189 979.00 76,083 324,775 979.10 76,606 332,409 Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 979.20 77,129 340,096 979.30 77,651 347,835 979.40 78,174 355,626 979.50 78,697 363,470 979.60 79,220 371,366 979.70 79,743 379,314 979.80 80,265 387,314 979.90 80,788 395,367 980.00 81,311 403,472 980.10 81,878 411,631 980.20 82,444 419,848 980.30 83,011 428,120 980.40 83,577 436,450 980.50 84,144 444,836 980.60 84,711 453,278 980.70 85,277 461,778 980.80 85,844 470,334 980.90 86,410 478,947 981.00 86,977 487,616 MSE 24-hr 3 10-Year Rainfall=4.26"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 25HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Time span=0.00-600.00 hrs, dt=0.01 hrs, 60001 points Runoff by SCS TR-20 method, UH=SCS, Weighted-Q Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method Peak Elev=997.22' Storage=249,161 cf Inflow=70.30 cfs 4.792 afPond 1P: FILTRATION/WETLAND Outflow=1.51 cfs 4.751 af Peak Elev=996.58' Storage=5,632 cf Inflow=11.55 cfs 0.648 afPond 8P: West Filtration Basin Primary=10.36 cfs 0.481 af Secondary=0.04 cfs 0.167 af Outflow=10.41 cfs 0.648 af Peak Elev=1,020.06' Storage=2,244 cf Inflow=5.15 cfs 0.293 afPond 9P: South Filtration Trench Primary=0.05 cfs 0.087 af Secondary=5.08 cfs 0.197 af Outflow=5.13 cfs 0.284 af Peak Elev=974.38' Storage=20,663 cf Inflow=12.02 cfs 5.446 afPond 10P: West Existing Wetland Outflow=2.25 cfs 5.441 af MSE 24-hr 3 10-Year Rainfall=4.26"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 26HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Summary for Pond 1P: FILTRATION/WETLAND Inflow Area = 19.209 ac, 42.35% Impervious, Inflow Depth = 2.99" for 10-Year event Inflow = 70.30 cfs @ 12.18 hrs, Volume= 4.792 af Outflow = 1.51 cfs @ 15.38 hrs, Volume= 4.751 af, Atten= 98%, Lag= 192.2 min Primary = 1.51 cfs @ 15.38 hrs, Volume= 4.751 af Routed to Reach 9R : (new Reach) Routing by Dyn-Stor-Ind method, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs Starting Elev= 994.00' Surf.Area= 77,114 sf Storage= 83,771 cf Peak Elev= 997.22' @ 15.38 hrs Surf.Area= 86,957 sf Storage= 249,161 cf (165,390 cf above start) Plug-Flow detention time= 5,817.7 min calculated for 2.828 af (59% of inflow) Center-of-Mass det. time= 3,588.5 min ( 4,365.8 - 777.3 ) Volume Invert Avail.Storage Storage Description #1 990.00' 16,422 cf West Forebay (Prismatic) Listed below (Recalc) #2 993.50' 1,015 cf West shallow wetland (Prismatic) Listed below (Recalc) #3 990.00' 18,942 cf Remnant Wetland (Prismatic) Listed below (Recalc) #4 989.00' 39,571 cf Middle Forebay (Prismatic) Listed below (Recalc) #5 993.50' 665 cf East shallow wetland (Prismatic) Listed below (Recalc) #6 992.00' 7,157 cf Filtration (Prismatic) Listed below (Recalc) -Impervious 23,856 cf Overall x 30.0% Voids #7 994.00' 336,285 cf Live Storage (Prismatic) Listed below (Recalc) 420,056 cf Total Available Storage Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 990.00 2,339 0 0 992.00 4,014 6,353 6,353 994.00 6,055 10,069 16,422 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 993.50 1,499 0 0 994.00 2,561 1,015 1,015 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 990.00 1,596 0 0 992.00 4,761 6,357 6,357 994.00 7,824 12,585 18,942 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 989.00 4,875 0 0 990.00 5,864 5,370 5,370 991.00 6,954 6,409 11,779 993.00 9,401 16,355 28,134 994.00 13,473 11,437 39,571 MSE 24-hr 3 10-Year Rainfall=4.26"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 27HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 993.50 961 0 0 994.00 1,698 665 665 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 992.00 11,928 0 0 994.00 11,928 23,856 23,856 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 994.00 45,503 0 0 995.00 49,888 47,696 47,696 996.00 53,188 51,538 99,234 998.00 56,729 109,917 209,151 1,000.00 70,405 127,134 336,285 Device Routing Invert Outlet Devices #1 Primary 990.90'15.0" Round Culvert L= 527.0' RCP, square edge headwall, Ke= 0.500 Inlet / Outlet Invert= 990.90' / 988.26' S= 0.0050 '/' Cc= 0.900 n= 0.013 Concrete sewer w/manholes & inlets, Flow Area= 1.23 sf #2 Device 1 999.10'6.0' long x 0.5' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 Coef. (English) 2.80 2.92 3.08 3.30 3.32 #3 Device 1 994.00'0.800 in/hr Filtration over Surface area above 994.00' Excluded Surface area = 77,114 sf #4 Device 1 995.00'6.0" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads Primary OutFlow Max=1.51 cfs @ 15.38 hrs HW=997.22' TW=986.60' (Dynamic Tailwater) 1=Culvert (Passes 1.51 cfs of 7.36 cfs potential flow) 2=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) 3=Filtration (Exfiltration Controls 0.18 cfs) 4=Orifice/Grate (Orifice Controls 1.33 cfs @ 6.76 fps) MSE 24-hr 3 10-Year Rainfall=4.26"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 28HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Pond 1P: FILTRATION/WETLAND Inflow Primary Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)75 70 65 60 55 50 45 40 35 30 25 20 15 10 5 0 Inflow Area=19.209 ac Peak Elev=997.22' Storage=249,161 cf 70.30 cfs 1.51 cfs MSE 24-hr 3 10-Year Rainfall=4.26"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 29HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Hydrograph for Pond 1P: FILTRATION/WETLAND Time (hours) Inflow (cfs) Storage (cubic-feet) Elevation (feet) Primary (cfs) 0.00 0.00 83,771 994.00 0.00 20.00 0.80 243,214 997.11 1.47 40.00 0.00 168,053 995.72 0.77 60.00 0.00 139,122 995.15 0.16 80.00 0.00 131,562 995.00 0.08 100.00 0.00 126,035 994.89 0.07 120.00 0.00 121,125 994.79 0.06 140.00 0.00 116,768 994.70 0.06 160.00 0.00 112,904 994.62 0.05 180.00 0.00 109,482 994.55 0.04 200.00 0.00 106,453 994.49 0.04 220.00 0.00 103,773 994.43 0.03 240.00 0.00 101,405 994.38 0.03 260.00 0.00 99,312 994.34 0.03 280.00 0.00 97,465 994.30 0.02 300.00 0.00 95,834 994.26 0.02 320.00 0.00 94,396 994.23 0.02 340.00 0.00 93,127 994.20 0.02 360.00 0.00 92,009 994.18 0.01 380.00 0.00 91,023 994.16 0.01 400.00 0.00 90,154 994.14 0.01 420.00 0.00 89,389 994.12 0.01 440.00 0.00 88,715 994.11 0.01 460.00 0.00 88,122 994.10 0.01 480.00 0.00 87,599 994.08 0.01 500.00 0.00 87,139 994.07 0.01 520.00 0.00 86,734 994.06 0.01 540.00 0.00 86,378 994.06 0.00 560.00 0.00 86,065 994.05 0.00 580.00 0.00 85,789 994.04 0.00 600.00 0.00 85,546 994.04 0.00 MSE 24-hr 3 10-Year Rainfall=4.26"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 30HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Stage-Area-Storage for Pond 1P: FILTRATION/WETLAND Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 989.00 4,875 0 989.20 5,073 995 989.40 5,271 2,029 989.60 5,468 3,103 989.80 5,666 4,216 990.00 9,799 5,370 990.20 10,501 7,400 990.40 11,203 9,570 990.60 11,905 11,881 990.80 12,607 14,332 991.00 13,309 16,924 991.20 14,038 19,658 991.40 14,766 22,539 991.60 15,495 25,565 991.80 16,224 28,737 992.00 16,953 32,054 992.20 17,708 36,236 992.40 18,463 40,569 992.60 19,218 45,052 992.80 19,973 49,687 993.00 20,728 54,473 993.20 22,053 59,467 993.40 23,378 64,725 993.60 27,522 70,513 993.80 29,567 76,938 994.00 77,114 83,771 994.20 77,991 92,959 994.40 78,868 102,323 994.60 79,745 111,862 994.80 80,622 121,577 995.00 81,499 131,467 995.20 82,159 141,510 995.40 82,819 151,686 995.60 83,479 161,993 995.80 84,139 172,433 996.00 84,799 183,005 996.20 85,153 193,678 996.40 85,507 204,421 996.60 85,861 215,236 996.80 86,215 226,122 997.00 86,570 237,078 997.20 86,924 248,105 997.40 87,278 259,203 997.60 87,632 270,372 997.80 87,986 281,611 998.00 88,340 292,922 998.20 89,708 304,404 998.40 91,075 316,160 998.60 92,443 328,190 998.80 93,810 340,493 999.00 95,178 353,070 999.20 96,546 365,920 Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 999.40 97,913 379,043 999.60 99,281 392,441 999.80 100,648 406,111 1,000.00 102,016 420,056 MSE 24-hr 3 10-Year Rainfall=4.26"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 31HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Summary for Pond 8P: West Filtration Basin Inflow Area = 2.967 ac, 23.03% Impervious, Inflow Depth = 2.62" for 10-Year event Inflow = 11.55 cfs @ 12.17 hrs, Volume= 0.648 af Outflow = 10.41 cfs @ 12.21 hrs, Volume= 0.648 af, Atten= 10%, Lag= 2.4 min Primary = 10.36 cfs @ 12.21 hrs, Volume= 0.481 af Routed to Reach 9R : (new Reach) Secondary = 0.04 cfs @ 12.21 hrs, Volume= 0.167 af Routed to Reach 9R : (new Reach) Routing by Dyn-Stor-Ind method, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs Peak Elev= 996.58' @ 12.21 hrs Surf.Area= 4,536 sf Storage= 5,632 cf Plug-Flow detention time= 511.8 min calculated for 0.648 af (100% of inflow) Center-of-Mass det. time= 512.1 min ( 1,300.9 - 788.8 ) Volume Invert Avail.Storage Storage Description #1 995.00' 16,956 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 995.00 2,655 0 0 996.00 3,804 3,230 3,230 996.50 4,432 2,059 5,289 997.00 5,109 2,385 7,674 998.00 6,579 5,844 13,518 998.50 7,173 3,438 16,956 Device Routing Invert Outlet Devices #1 Secondary 995.00'1.000 in/hr Filtration over Surface area above 995.00' Excluded Surface area = 2,655 sf #2 Primary 992.00'15.0" Round Culvert L= 22.0' RCP, mitered to conform to fill, Ke= 0.700 Inlet / Outlet Invert= 992.00' / 991.00' S= 0.0455 '/' Cc= 0.900 n= 0.013, Flow Area= 1.23 sf #3 Device 2 996.50'48.0" Horiz. Orifice/Grate C= 0.600 Primary OutFlow Max=10.36 cfs @ 12.21 hrs HW=996.58' TW=986.92' (Dynamic Tailwater) 2=Culvert (Inlet Controls 10.36 cfs @ 8.45 fps) 3=Orifice/Grate (Passes 10.36 cfs of 16.71 cfs potential flow) Secondary OutFlow Max=0.04 cfs @ 12.21 hrs HW=996.58' TW=986.92' (Dynamic Tailwater) 1=Filtration (Exfiltration Controls 0.04 cfs) MSE 24-hr 3 10-Year Rainfall=4.26"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 32HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Pond 8P: West Filtration Basin Inflow Outflow Primary Secondary Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)12 11 10 9 8 7 6 5 4 3 2 1 0 Inflow Area=2.967 ac Peak Elev=996.58' Storage=5,632 cf 11.55 cfs 10.41 cfs 10.36 cfs 0.04 cfs MSE 24-hr 3 10-Year Rainfall=4.26"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 33HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Hydrograph for Pond 8P: West Filtration Basin Time (hours) Inflow (cfs) Storage (cubic-feet) Elevation (feet) Outflow (cfs) Primary (cfs) Secondary (cfs) 0.00 0.00 0 995.00 0.00 0.00 0.00 20.00 0.12 5,289 996.50 0.12 0.08 0.04 40.00 0.00 3,339 996.03 0.03 0.00 0.03 60.00 0.00 1,805 995.60 0.02 0.00 0.02 80.00 0.00 936 995.33 0.01 0.00 0.01 100.00 0.00 472 995.17 0.00 0.00 0.00 120.00 0.00 234 995.09 0.00 0.00 0.00 140.00 0.00 115 995.04 0.00 0.00 0.00 160.00 0.00 56 995.02 0.00 0.00 0.00 180.00 0.00 27 995.01 0.00 0.00 0.00 200.00 0.00 13 995.00 0.00 0.00 0.00 220.00 0.00 6 995.00 0.00 0.00 0.00 240.00 0.00 3 995.00 0.00 0.00 0.00 260.00 0.00 2 995.00 0.00 0.00 0.00 280.00 0.00 1 995.00 0.00 0.00 0.00 300.00 0.00 0 995.00 0.00 0.00 0.00 320.00 0.00 0 995.00 0.00 0.00 0.00 340.00 0.00 0 995.00 0.00 0.00 0.00 360.00 0.00 0 995.00 0.00 0.00 0.00 380.00 0.00 0 995.00 0.00 0.00 0.00 400.00 0.00 0 995.00 0.00 0.00 0.00 420.00 0.00 0 995.00 0.00 0.00 0.00 440.00 0.00 0 995.00 0.00 0.00 0.00 460.00 0.00 0 995.00 0.00 0.00 0.00 480.00 0.00 0 995.00 0.00 0.00 0.00 500.00 0.00 0 995.00 0.00 0.00 0.00 520.00 0.00 0 995.00 0.00 0.00 0.00 540.00 0.00 0 995.00 0.00 0.00 0.00 560.00 0.00 0 995.00 0.00 0.00 0.00 580.00 0.00 0 995.00 0.00 0.00 0.00 600.00 0.00 0 995.00 0.00 0.00 0.00 MSE 24-hr 3 10-Year Rainfall=4.26"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 34HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Stage-Area-Storage for Pond 8P: West Filtration Basin Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 995.00 2,655 0 995.05 2,712 134 995.10 2,770 271 995.15 2,827 411 995.20 2,885 554 995.25 2,942 700 995.30 3,000 848 995.35 3,057 1,000 995.40 3,115 1,154 995.45 3,172 1,311 995.50 3,230 1,471 995.55 3,287 1,634 995.60 3,344 1,800 995.65 3,402 1,968 995.70 3,459 2,140 995.75 3,517 2,314 995.80 3,574 2,492 995.85 3,632 2,672 995.90 3,689 2,855 995.95 3,747 3,041 996.00 3,804 3,230 996.05 3,867 3,421 996.10 3,930 3,616 996.15 3,992 3,814 996.20 4,055 4,015 996.25 4,118 4,220 996.30 4,181 4,427 996.35 4,244 4,638 996.40 4,306 4,852 996.45 4,369 5,068 996.50 4,432 5,289 996.55 4,500 5,512 996.60 4,567 5,738 996.65 4,635 5,969 996.70 4,703 6,202 996.75 4,771 6,439 996.80 4,838 6,679 996.85 4,906 6,923 996.90 4,974 7,170 996.95 5,041 7,420 997.00 5,109 7,674 997.05 5,182 7,931 997.10 5,256 8,192 997.15 5,329 8,457 997.20 5,403 8,725 997.25 5,477 8,997 997.30 5,550 9,273 997.35 5,624 9,552 997.40 5,697 9,835 997.45 5,771 10,122 997.50 5,844 10,412 997.55 5,917 10,706 Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 997.60 5,991 11,004 997.65 6,064 11,305 997.70 6,138 11,610 997.75 6,212 11,919 997.80 6,285 12,231 997.85 6,359 12,547 997.90 6,432 12,867 997.95 6,506 13,191 998.00 6,579 13,518 998.05 6,638 13,848 998.10 6,698 14,182 998.15 6,757 14,518 998.20 6,817 14,857 998.25 6,876 15,200 998.30 6,935 15,545 998.35 6,995 15,893 998.40 7,054 16,244 998.45 7,114 16,599 998.50 7,173 16,956 MSE 24-hr 3 10-Year Rainfall=4.26"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 35HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Summary for Pond 9P: South Filtration Trench Inflow Area = 1.353 ac, 19.13% Impervious, Inflow Depth = 2.60" for 10-Year event Inflow = 5.15 cfs @ 12.17 hrs, Volume= 0.293 af Outflow = 5.13 cfs @ 12.18 hrs, Volume= 0.284 af, Atten= 0%, Lag= 0.4 min Primary = 0.05 cfs @ 12.18 hrs, Volume= 0.087 af Routed to Link 3L : SOUTH Secondary = 5.08 cfs @ 12.18 hrs, Volume= 0.197 af Routed to Link 3L : SOUTH Routing by Dyn-Stor-Ind method, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs Peak Elev= 1,020.06' @ 12.18 hrs Surf.Area= 3,513 sf Storage= 2,244 cf Plug-Flow detention time= 175.9 min calculated for 0.284 af (97% of inflow) Center-of-Mass det. time= 159.9 min ( 951.3 - 791.4 ) Volume Invert Avail.Storage Storage Description #1 1,017.25' 368 cf Filter Storage (Min) (Prismatic) Listed below (Recalc) 1,050 cf Overall x 35.0% Voids #2 1,019.00' 3,345 cf Live Storage (Prismatic) Listed below (Recalc) 3,712 cf Total Available Storage Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 1,017.25 600 0 0 1,019.00 600 1,050 1,050 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 1,019.00 600 0 0 1,019.50 1,714 579 579 1,020.00 2,800 1,129 1,707 1,020.50 3,750 1,638 3,345 Device Routing Invert Outlet Devices #1 Primary 1,015.00'12.0" Round Culvert L= 200.0' RCP, square edge headwall, Ke= 0.500 Inlet / Outlet Invert= 1,015.00' / 1,000.00' S= 0.0750 '/' Cc= 0.900 n= 0.013 Concrete pipe, bends & connections, Flow Area= 0.79 sf #2 Device 1 1,019.00'1.000 in/hr Filtration over Surface area above 1,019.00' Excluded Surface area = 1,200 sf #3 Secondary 1,020.00'130.0' long + 3.0 '/' SideZ x 1.0' 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 Coef. (English) 2.69 2.72 2.75 2.85 2.98 3.08 3.20 3.28 3.31 3.30 3.31 3.32 MSE 24-hr 3 10-Year Rainfall=4.26"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 36HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Primary OutFlow Max=0.05 cfs @ 12.18 hrs HW=1,020.06' TW=0.00' (Dynamic Tailwater) 1=Culvert (Passes 0.05 cfs of 8.07 cfs potential flow) 2=Filtration (Exfiltration Controls 0.05 cfs) Secondary OutFlow Max=5.07 cfs @ 12.18 hrs HW=1,020.06' TW=0.00' (Dynamic Tailwater) 3=Broad-Crested Rectangular Weir (Weir Controls 5.07 cfs @ 0.66 fps) Pond 9P: South Filtration Trench Inflow Outflow Primary Secondary Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)5 4 3 2 1 0 Inflow Area=1.353 ac Peak Elev=1,020.06' Storage=2,244 cf 5.15 cfs 5.13 cfs 0.05 cfs 5.08 cfs MSE 24-hr 3 10-Year Rainfall=4.26"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 37HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Hydrograph for Pond 9P: South Filtration Trench Time (hours) Inflow (cfs) Storage (cubic-feet) Elevation (feet) Outflow (cfs) Primary (cfs) Secondary (cfs) 0.00 0.00 0 1,017.25 0.00 0.00 0.00 20.00 0.05 2,076 1,020.00 0.05 0.05 0.00 40.00 0.00 461 1,019.13 0.01 0.01 0.00 60.00 0.00 368 1,019.00 0.00 0.00 0.00 80.00 0.00 368 1,019.00 0.00 0.00 0.00 100.00 0.00 368 1,019.00 0.00 0.00 0.00 120.00 0.00 368 1,019.00 0.00 0.00 0.00 140.00 0.00 368 1,019.00 0.00 0.00 0.00 160.00 0.00 368 1,019.00 0.00 0.00 0.00 180.00 0.00 368 1,019.00 0.00 0.00 0.00 200.00 0.00 368 1,019.00 0.00 0.00 0.00 220.00 0.00 368 1,019.00 0.00 0.00 0.00 240.00 0.00 368 1,019.00 0.00 0.00 0.00 260.00 0.00 368 1,019.00 0.00 0.00 0.00 280.00 0.00 368 1,019.00 0.00 0.00 0.00 300.00 0.00 368 1,019.00 0.00 0.00 0.00 320.00 0.00 368 1,019.00 0.00 0.00 0.00 340.00 0.00 368 1,019.00 0.00 0.00 0.00 360.00 0.00 368 1,019.00 0.00 0.00 0.00 380.00 0.00 368 1,019.00 0.00 0.00 0.00 400.00 0.00 368 1,019.00 0.00 0.00 0.00 420.00 0.00 368 1,019.00 0.00 0.00 0.00 440.00 0.00 368 1,019.00 0.00 0.00 0.00 460.00 0.00 368 1,019.00 0.00 0.00 0.00 480.00 0.00 368 1,019.00 0.00 0.00 0.00 500.00 0.00 368 1,019.00 0.00 0.00 0.00 520.00 0.00 368 1,019.00 0.00 0.00 0.00 540.00 0.00 368 1,019.00 0.00 0.00 0.00 560.00 0.00 368 1,019.00 0.00 0.00 0.00 580.00 0.00 368 1,019.00 0.00 0.00 0.00 600.00 0.00 368 1,019.00 0.00 0.00 0.00 MSE 24-hr 3 10-Year Rainfall=4.26"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 38HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Stage-Area-Storage for Pond 9P: South Filtration Trench Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 1,017.25 600 0 1,017.30 600 10 1,017.35 600 21 1,017.40 600 31 1,017.45 600 42 1,017.50 600 53 1,017.55 600 63 1,017.60 600 74 1,017.65 600 84 1,017.70 600 95 1,017.75 600 105 1,017.80 600 115 1,017.85 600 126 1,017.90 600 136 1,017.95 600 147 1,018.00 600 158 1,018.05 600 168 1,018.10 600 179 1,018.15 600 189 1,018.20 600 200 1,018.25 600 210 1,018.30 600 220 1,018.35 600 231 1,018.40 600 241 1,018.45 600 252 1,018.50 600 263 1,018.55 600 273 1,018.60 600 284 1,018.65 600 294 1,018.70 600 305 1,018.75 600 315 1,018.80 600 325 1,018.85 600 336 1,018.90 600 346 1,018.95 600 357 1,019.00 1,200 368 1,019.05 1,311 400 1,019.10 1,423 439 1,019.15 1,534 483 1,019.20 1,646 532 1,019.25 1,757 587 1,019.30 1,868 648 1,019.35 1,980 714 1,019.40 2,091 786 1,019.45 2,203 863 1,019.50 2,314 946 1,019.55 2,423 1,034 1,019.60 2,531 1,128 1,019.65 2,640 1,228 1,019.70 2,748 1,332 1,019.75 2,857 1,442 1,019.80 2,966 1,558 Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 1,019.85 3,074 1,679 1,019.90 3,183 1,805 1,019.95 3,291 1,937 1,020.00 3,400 2,075 1,020.05 3,495 2,217 1,020.10 3,590 2,364 1,020.15 3,685 2,516 1,020.20 3,780 2,673 1,020.25 3,875 2,834 1,020.30 3,970 3,000 1,020.35 4,065 3,171 1,020.40 4,160 3,346 1,020.45 4,255 3,527 1,020.50 4,350 3,712 MSE 24-hr 3 10-Year Rainfall=4.26"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 39HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Summary for Pond 10P: West Existing Wetland Inflow Area = 22.414 ac, 39.34% Impervious, Inflow Depth > 2.92" for 10-Year event Inflow = 12.02 cfs @ 12.19 hrs, Volume= 5.446 af Outflow = 2.25 cfs @ 13.43 hrs, Volume= 5.441 af, Atten= 81%, Lag= 74.6 min Primary = 2.25 cfs @ 13.43 hrs, Volume= 5.441 af Routed to Link 7L : TOTAL Routing by Dyn-Stor-Ind method, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs Starting Elev= 974.10' Surf.Area= 54,326 sf Storage= 5,411 cf Peak Elev= 974.38' @ 13.43 hrs Surf.Area= 55,529 sf Storage= 20,663 cf (15,252 cf above start) Plug-Flow detention time= 840.1 min calculated for 5.317 af (98% of inflow) Center-of-Mass det. time= 184.3 min ( 4,154.8 - 3,970.5 ) Volume Invert Avail.Storage Storage Description #1 974.00' 487,616 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 974.00 53,893 0 0 975.00 58,226 56,060 56,060 976.00 62,886 60,556 116,616 977.00 67,093 64,990 181,605 978.00 71,582 69,338 250,943 979.00 76,083 73,833 324,775 980.00 81,311 78,697 403,472 981.00 86,977 84,144 487,616 Device Routing Invert Outlet Devices #1 Primary 974.10'18.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads Primary OutFlow Max=2.25 cfs @ 13.43 hrs HW=974.38' TW=0.00' (Dynamic Tailwater) 1=Orifice/Grate (Weir Controls 2.25 cfs @ 1.72 fps) MSE 24-hr 3 10-Year Rainfall=4.26"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 40HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Pond 10P: West Existing Wetland Inflow Primary Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)13 12 11 10 9 8 7 6 5 4 3 2 1 0 Inflow Area=22.414 ac Peak Elev=974.38' Storage=20,663 cf 12.02 cfs 2.25 cfs MSE 24-hr 3 10-Year Rainfall=4.26"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 41HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Hydrograph for Pond 10P: West Existing Wetland Time (hours) Inflow (cfs) Storage (cubic-feet) Elevation (feet) Primary (cfs) 0.00 0.00 5,411 974.10 0.00 20.00 1.60 17,779 974.33 1.65 40.00 0.80 13,431 974.25 0.87 60.00 0.17 8,539 974.16 0.21 80.00 0.09 7,248 974.13 0.10 100.00 0.08 7,030 974.13 0.08 120.00 0.07 6,880 974.13 0.07 140.00 0.06 6,753 974.12 0.06 160.00 0.05 6,642 974.12 0.05 180.00 0.04 6,543 974.12 0.05 200.00 0.04 6,453 974.12 0.04 220.00 0.04 6,370 974.12 0.04 240.00 0.03 6,295 974.12 0.03 260.00 0.03 6,225 974.11 0.03 280.00 0.02 6,161 974.11 0.02 300.00 0.02 6,101 974.11 0.02 320.00 0.02 6,047 974.11 0.02 340.00 0.02 5,996 974.11 0.02 360.00 0.01 5,949 974.11 0.02 380.00 0.01 5,906 974.11 0.01 400.00 0.01 5,867 974.11 0.01 420.00 0.01 5,831 974.11 0.01 440.00 0.01 5,797 974.11 0.01 460.00 0.01 5,766 974.11 0.01 480.00 0.01 5,738 974.11 0.01 500.00 0.01 5,712 974.11 0.01 520.00 0.01 5,687 974.11 0.01 540.00 0.00 5,665 974.10 0.00 560.00 0.00 5,644 974.10 0.00 580.00 0.00 5,626 974.10 0.00 600.00 0.00 5,608 974.10 0.00 MSE 24-hr 3 10-Year Rainfall=4.26"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 42HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Stage-Area-Storage for Pond 10P: West Existing Wetland Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 974.00 53,893 0 974.10 54,326 5,411 974.20 54,760 10,865 974.30 55,193 16,363 974.40 55,626 21,904 974.50 56,060 27,488 974.60 56,493 33,116 974.70 56,926 38,787 974.80 57,359 44,501 974.90 57,793 50,259 975.00 58,226 56,060 975.10 58,692 61,905 975.20 59,158 67,798 975.30 59,624 73,737 975.40 60,090 79,723 975.50 60,556 85,755 975.60 61,022 91,834 975.70 61,488 97,959 975.80 61,954 104,131 975.90 62,420 110,350 976.00 62,886 116,616 976.10 63,307 122,925 976.20 63,727 129,277 976.30 64,148 135,671 976.40 64,569 142,106 976.50 64,990 148,584 976.60 65,410 155,104 976.70 65,831 161,666 976.80 66,252 168,271 976.90 66,672 174,917 977.00 67,093 181,605 977.10 67,542 188,337 977.20 67,991 195,113 977.30 68,440 201,935 977.40 68,889 208,801 977.50 69,338 215,713 977.60 69,786 222,669 977.70 70,235 229,670 977.80 70,684 236,716 977.90 71,133 243,807 978.00 71,582 250,943 978.10 72,032 258,123 978.20 72,482 265,349 978.30 72,932 272,620 978.40 73,382 279,935 978.50 73,833 287,296 978.60 74,283 294,702 978.70 74,733 302,153 978.80 75,183 309,648 978.90 75,633 317,189 979.00 76,083 324,775 979.10 76,606 332,409 Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 979.20 77,129 340,096 979.30 77,651 347,835 979.40 78,174 355,626 979.50 78,697 363,470 979.60 79,220 371,366 979.70 79,743 379,314 979.80 80,265 387,314 979.90 80,788 395,367 980.00 81,311 403,472 980.10 81,878 411,631 980.20 82,444 419,848 980.30 83,011 428,120 980.40 83,577 436,450 980.50 84,144 444,836 980.60 84,711 453,278 980.70 85,277 461,778 980.80 85,844 470,334 980.90 86,410 478,947 981.00 86,977 487,616 MSE 24-hr 3 100-Year Rainfall=7.38"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 43HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Time span=0.00-600.00 hrs, dt=0.01 hrs, 60001 points Runoff by SCS TR-20 method, UH=SCS, Weighted-Q Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method Peak Elev=999.57' Storage=390,088 cf Inflow=137.66 cfs 9.469 afPond 1P: FILTRATION/WETLAND Outflow=8.03 cfs 9.423 af Peak Elev=997.81' Storage=12,293 cf Inflow=23.81 cfs 1.351 afPond 8P: West Filtration Basin Primary=11.87 cfs 1.178 af Secondary=0.08 cfs 0.173 af Outflow=11.96 cfs 1.351 af Peak Elev=1,020.10' Storage=2,355 cf Inflow=10.65 cfs 0.614 afPond 9P: South Filtration Trench Primary=0.06 cfs 0.098 af Secondary=10.57 cfs 0.508 af Outflow=10.63 cfs 0.606 af Peak Elev=974.84' Storage=46,686 cf Inflow=14.83 cfs 10.878 afPond 10P: West Existing Wetland Outflow=7.31 cfs 10.873 af MSE 24-hr 3 100-Year Rainfall=7.38"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 44HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Summary for Pond 1P: FILTRATION/WETLAND Inflow Area = 19.209 ac, 42.35% Impervious, Inflow Depth = 5.92" for 100-Year event Inflow = 137.66 cfs @ 12.18 hrs, Volume= 9.469 af Outflow = 8.03 cfs @ 13.58 hrs, Volume= 9.423 af, Atten= 94%, Lag= 84.2 min Primary = 8.03 cfs @ 13.58 hrs, Volume= 9.423 af Routed to Reach 9R : (new Reach) Routing by Dyn-Stor-Ind method, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs Starting Elev= 994.00' Surf.Area= 77,114 sf Storage= 83,771 cf Peak Elev= 999.57' @ 13.58 hrs Surf.Area= 99,043 sf Storage= 390,088 cf (306,317 cf above start) Plug-Flow detention time= 3,239.3 min calculated for 7.500 af (79% of inflow) Center-of-Mass det. time= 2,546.2 min ( 3,315.4 - 769.2 ) Volume Invert Avail.Storage Storage Description #1 990.00' 16,422 cf West Forebay (Prismatic) Listed below (Recalc) #2 993.50' 1,015 cf West shallow wetland (Prismatic) Listed below (Recalc) #3 990.00' 18,942 cf Remnant Wetland (Prismatic) Listed below (Recalc) #4 989.00' 39,571 cf Middle Forebay (Prismatic) Listed below (Recalc) #5 993.50' 665 cf East shallow wetland (Prismatic) Listed below (Recalc) #6 992.00' 7,157 cf Filtration (Prismatic) Listed below (Recalc) -Impervious 23,856 cf Overall x 30.0% Voids #7 994.00' 336,285 cf Live Storage (Prismatic) Listed below (Recalc) 420,056 cf Total Available Storage Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 990.00 2,339 0 0 992.00 4,014 6,353 6,353 994.00 6,055 10,069 16,422 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 993.50 1,499 0 0 994.00 2,561 1,015 1,015 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 990.00 1,596 0 0 992.00 4,761 6,357 6,357 994.00 7,824 12,585 18,942 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 989.00 4,875 0 0 990.00 5,864 5,370 5,370 991.00 6,954 6,409 11,779 993.00 9,401 16,355 28,134 994.00 13,473 11,437 39,571 MSE 24-hr 3 100-Year Rainfall=7.38"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 45HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 993.50 961 0 0 994.00 1,698 665 665 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 992.00 11,928 0 0 994.00 11,928 23,856 23,856 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 994.00 45,503 0 0 995.00 49,888 47,696 47,696 996.00 53,188 51,538 99,234 998.00 56,729 109,917 209,151 1,000.00 70,405 127,134 336,285 Device Routing Invert Outlet Devices #1 Primary 990.90'15.0" Round Culvert L= 527.0' RCP, square edge headwall, Ke= 0.500 Inlet / Outlet Invert= 990.90' / 988.26' S= 0.0050 '/' Cc= 0.900 n= 0.013 Concrete sewer w/manholes & inlets, Flow Area= 1.23 sf #2 Device 1 999.10'6.0' long x 0.5' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 Coef. (English) 2.80 2.92 3.08 3.30 3.32 #3 Device 1 994.00'0.800 in/hr Filtration over Surface area above 994.00' Excluded Surface area = 77,114 sf #4 Device 1 995.00'6.0" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads Primary OutFlow Max=8.03 cfs @ 13.58 hrs HW=999.57' TW=986.87' (Dynamic Tailwater) 1=Culvert (Passes 8.03 cfs of 8.41 cfs potential flow) 2=Broad-Crested Rectangular Weir (Weir Controls 5.66 cfs @ 2.03 fps) 3=Filtration (Exfiltration Controls 0.41 cfs) 4=Orifice/Grate (Orifice Controls 1.96 cfs @ 10.00 fps) MSE 24-hr 3 100-Year Rainfall=7.38"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 46HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Pond 1P: FILTRATION/WETLAND Inflow Primary Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0 Inflow Area=19.209 ac Peak Elev=999.57' Storage=390,088 cf 137.66 cfs 8.03 cfs MSE 24-hr 3 100-Year Rainfall=7.38"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 47HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Hydrograph for Pond 1P: FILTRATION/WETLAND Time (hours) Inflow (cfs) Storage (cubic-feet) Elevation (feet) Primary (cfs) 0.00 0.00 83,771 994.00 0.00 20.00 1.48 360,898 999.12 2.27 40.00 0.00 241,813 997.09 1.46 60.00 0.00 163,496 995.63 0.70 80.00 0.00 138,194 995.13 0.14 100.00 0.00 131,061 994.99 0.08 120.00 0.00 125,590 994.88 0.07 140.00 0.00 120,730 994.78 0.06 160.00 0.00 116,417 994.69 0.06 180.00 0.00 112,594 994.62 0.05 200.00 0.00 109,207 994.54 0.04 220.00 0.00 106,209 994.48 0.04 240.00 0.00 103,558 994.43 0.03 260.00 0.00 101,215 994.38 0.03 280.00 0.00 99,144 994.33 0.03 300.00 0.00 97,316 994.29 0.02 320.00 0.00 95,703 994.26 0.02 340.00 0.00 94,280 994.23 0.02 360.00 0.00 93,025 994.20 0.02 380.00 0.00 91,919 994.18 0.01 400.00 0.00 90,944 994.16 0.01 420.00 0.00 90,085 994.14 0.01 440.00 0.00 89,328 994.12 0.01 460.00 0.00 88,661 994.11 0.01 480.00 0.00 88,074 994.09 0.01 500.00 0.00 87,557 994.08 0.01 520.00 0.00 87,102 994.07 0.01 540.00 0.00 86,702 994.06 0.01 560.00 0.00 86,350 994.06 0.00 580.00 0.00 86,039 994.05 0.00 600.00 0.00 85,766 994.04 0.00 MSE 24-hr 3 100-Year Rainfall=7.38"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 48HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Stage-Area-Storage for Pond 1P: FILTRATION/WETLAND Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 989.00 4,875 0 989.20 5,073 995 989.40 5,271 2,029 989.60 5,468 3,103 989.80 5,666 4,216 990.00 9,799 5,370 990.20 10,501 7,400 990.40 11,203 9,570 990.60 11,905 11,881 990.80 12,607 14,332 991.00 13,309 16,924 991.20 14,038 19,658 991.40 14,766 22,539 991.60 15,495 25,565 991.80 16,224 28,737 992.00 16,953 32,054 992.20 17,708 36,236 992.40 18,463 40,569 992.60 19,218 45,052 992.80 19,973 49,687 993.00 20,728 54,473 993.20 22,053 59,467 993.40 23,378 64,725 993.60 27,522 70,513 993.80 29,567 76,938 994.00 77,114 83,771 994.20 77,991 92,959 994.40 78,868 102,323 994.60 79,745 111,862 994.80 80,622 121,577 995.00 81,499 131,467 995.20 82,159 141,510 995.40 82,819 151,686 995.60 83,479 161,993 995.80 84,139 172,433 996.00 84,799 183,005 996.20 85,153 193,678 996.40 85,507 204,421 996.60 85,861 215,236 996.80 86,215 226,122 997.00 86,570 237,078 997.20 86,924 248,105 997.40 87,278 259,203 997.60 87,632 270,372 997.80 87,986 281,611 998.00 88,340 292,922 998.20 89,708 304,404 998.40 91,075 316,160 998.60 92,443 328,190 998.80 93,810 340,493 999.00 95,178 353,070 999.20 96,546 365,920 Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 999.40 97,913 379,043 999.60 99,281 392,441 999.80 100,648 406,111 1,000.00 102,016 420,056 MSE 24-hr 3 100-Year Rainfall=7.38"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 49HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Summary for Pond 8P: West Filtration Basin [87] Warning: Oscillations may require smaller dt or Finer Routing (severity=4) Inflow Area = 2.967 ac, 23.03% Impervious, Inflow Depth = 5.47" for 100-Year event Inflow = 23.81 cfs @ 12.17 hrs, Volume= 1.351 af Outflow = 11.96 cfs @ 12.31 hrs, Volume= 1.351 af, Atten= 50%, Lag= 8.2 min Primary = 11.87 cfs @ 12.31 hrs, Volume= 1.178 af Routed to Reach 9R : (new Reach) Secondary = 0.08 cfs @ 12.31 hrs, Volume= 0.173 af Routed to Reach 9R : (new Reach) Routing by Dyn-Stor-Ind method, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs Peak Elev= 997.81' @ 12.31 hrs Surf.Area= 6,299 sf Storage= 12,293 cf Plug-Flow detention time= 256.3 min calculated for 1.351 af (100% of inflow) Center-of-Mass det. time= 256.2 min ( 1,034.5 - 778.4 ) Volume Invert Avail.Storage Storage Description #1 995.00' 16,956 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 995.00 2,655 0 0 996.00 3,804 3,230 3,230 996.50 4,432 2,059 5,289 997.00 5,109 2,385 7,674 998.00 6,579 5,844 13,518 998.50 7,173 3,438 16,956 Device Routing Invert Outlet Devices #1 Secondary 995.00'1.000 in/hr Filtration over Surface area above 995.00' Excluded Surface area = 2,655 sf #2 Primary 992.00'15.0" Round Culvert L= 22.0' RCP, mitered to conform to fill, Ke= 0.700 Inlet / Outlet Invert= 992.00' / 991.00' S= 0.0455 '/' Cc= 0.900 n= 0.013, Flow Area= 1.23 sf #3 Device 2 996.50'48.0" Horiz. Orifice/Grate C= 0.600 Primary OutFlow Max=11.87 cfs @ 12.31 hrs HW=997.81' TW=986.99' (Dynamic Tailwater) 2=Culvert (Inlet Controls 11.87 cfs @ 9.67 fps) 3=Orifice/Grate (Passes 11.87 cfs of 69.24 cfs potential flow) Secondary OutFlow Max=0.08 cfs @ 12.31 hrs HW=997.81' TW=986.99' (Dynamic Tailwater) 1=Filtration (Exfiltration Controls 0.08 cfs) MSE 24-hr 3 100-Year Rainfall=7.38"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 50HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Pond 8P: West Filtration Basin Inflow Outflow Primary Secondary Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)26 24 22 20 18 16 14 12 10 8 6 4 2 0 Inflow Area=2.967 ac Peak Elev=997.81' Storage=12,293 cf 23.81 cfs 11.96 cfs 11.87 cfs 0.08 cfs MSE 24-hr 3 100-Year Rainfall=7.38"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 51HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Hydrograph for Pond 8P: West Filtration Basin Time (hours) Inflow (cfs) Storage (cubic-feet) Elevation (feet) Outflow (cfs) Primary (cfs) Secondary (cfs) 0.00 0.00 0 995.00 0.00 0.00 0.00 20.00 0.22 5,289 996.50 0.22 0.18 0.04 40.00 0.00 3,350 996.03 0.03 0.00 0.03 60.00 0.00 1,812 995.60 0.02 0.00 0.02 80.00 0.00 939 995.33 0.01 0.00 0.01 100.00 0.00 473 995.17 0.00 0.00 0.00 120.00 0.00 235 995.09 0.00 0.00 0.00 140.00 0.00 115 995.04 0.00 0.00 0.00 160.00 0.00 56 995.02 0.00 0.00 0.00 180.00 0.00 27 995.01 0.00 0.00 0.00 200.00 0.00 13 995.01 0.00 0.00 0.00 220.00 0.00 6 995.00 0.00 0.00 0.00 240.00 0.00 3 995.00 0.00 0.00 0.00 260.00 0.00 2 995.00 0.00 0.00 0.00 280.00 0.00 1 995.00 0.00 0.00 0.00 300.00 0.00 0 995.00 0.00 0.00 0.00 320.00 0.00 0 995.00 0.00 0.00 0.00 340.00 0.00 0 995.00 0.00 0.00 0.00 360.00 0.00 0 995.00 0.00 0.00 0.00 380.00 0.00 0 995.00 0.00 0.00 0.00 400.00 0.00 0 995.00 0.00 0.00 0.00 420.00 0.00 0 995.00 0.00 0.00 0.00 440.00 0.00 0 995.00 0.00 0.00 0.00 460.00 0.00 0 995.00 0.00 0.00 0.00 480.00 0.00 0 995.00 0.00 0.00 0.00 500.00 0.00 0 995.00 0.00 0.00 0.00 520.00 0.00 0 995.00 0.00 0.00 0.00 540.00 0.00 0 995.00 0.00 0.00 0.00 560.00 0.00 0 995.00 0.00 0.00 0.00 580.00 0.00 0 995.00 0.00 0.00 0.00 600.00 0.00 0 995.00 0.00 0.00 0.00 MSE 24-hr 3 100-Year Rainfall=7.38"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 52HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Stage-Area-Storage for Pond 8P: West Filtration Basin Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 995.00 2,655 0 995.05 2,712 134 995.10 2,770 271 995.15 2,827 411 995.20 2,885 554 995.25 2,942 700 995.30 3,000 848 995.35 3,057 1,000 995.40 3,115 1,154 995.45 3,172 1,311 995.50 3,230 1,471 995.55 3,287 1,634 995.60 3,344 1,800 995.65 3,402 1,968 995.70 3,459 2,140 995.75 3,517 2,314 995.80 3,574 2,492 995.85 3,632 2,672 995.90 3,689 2,855 995.95 3,747 3,041 996.00 3,804 3,230 996.05 3,867 3,421 996.10 3,930 3,616 996.15 3,992 3,814 996.20 4,055 4,015 996.25 4,118 4,220 996.30 4,181 4,427 996.35 4,244 4,638 996.40 4,306 4,852 996.45 4,369 5,068 996.50 4,432 5,289 996.55 4,500 5,512 996.60 4,567 5,738 996.65 4,635 5,969 996.70 4,703 6,202 996.75 4,771 6,439 996.80 4,838 6,679 996.85 4,906 6,923 996.90 4,974 7,170 996.95 5,041 7,420 997.00 5,109 7,674 997.05 5,182 7,931 997.10 5,256 8,192 997.15 5,329 8,457 997.20 5,403 8,725 997.25 5,477 8,997 997.30 5,550 9,273 997.35 5,624 9,552 997.40 5,697 9,835 997.45 5,771 10,122 997.50 5,844 10,412 997.55 5,917 10,706 Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 997.60 5,991 11,004 997.65 6,064 11,305 997.70 6,138 11,610 997.75 6,212 11,919 997.80 6,285 12,231 997.85 6,359 12,547 997.90 6,432 12,867 997.95 6,506 13,191 998.00 6,579 13,518 998.05 6,638 13,848 998.10 6,698 14,182 998.15 6,757 14,518 998.20 6,817 14,857 998.25 6,876 15,200 998.30 6,935 15,545 998.35 6,995 15,893 998.40 7,054 16,244 998.45 7,114 16,599 998.50 7,173 16,956 MSE 24-hr 3 100-Year Rainfall=7.38"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 53HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Summary for Pond 9P: South Filtration Trench Inflow Area = 1.353 ac, 19.13% Impervious, Inflow Depth = 5.45" for 100-Year event Inflow = 10.65 cfs @ 12.17 hrs, Volume= 0.614 af Outflow = 10.63 cfs @ 12.17 hrs, Volume= 0.606 af, Atten= 0%, Lag= 0.3 min Primary = 0.06 cfs @ 12.17 hrs, Volume= 0.098 af Routed to Link 3L : SOUTH Secondary = 10.57 cfs @ 12.17 hrs, Volume= 0.508 af Routed to Link 3L : SOUTH Routing by Dyn-Stor-Ind method, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs Peak Elev= 1,020.10' @ 12.17 hrs Surf.Area= 3,584 sf Storage= 2,355 cf Plug-Flow detention time= 94.3 min calculated for 0.606 af (99% of inflow) Center-of-Mass det. time= 86.1 min ( 866.3 - 780.3 ) Volume Invert Avail.Storage Storage Description #1 1,017.25' 368 cf Filter Storage (Min) (Prismatic) Listed below (Recalc) 1,050 cf Overall x 35.0% Voids #2 1,019.00' 3,345 cf Live Storage (Prismatic) Listed below (Recalc) 3,712 cf Total Available Storage Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 1,017.25 600 0 0 1,019.00 600 1,050 1,050 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 1,019.00 600 0 0 1,019.50 1,714 579 579 1,020.00 2,800 1,129 1,707 1,020.50 3,750 1,638 3,345 Device Routing Invert Outlet Devices #1 Primary 1,015.00'12.0" Round Culvert L= 200.0' RCP, square edge headwall, Ke= 0.500 Inlet / Outlet Invert= 1,015.00' / 1,000.00' S= 0.0750 '/' Cc= 0.900 n= 0.013 Concrete pipe, bends & connections, Flow Area= 0.79 sf #2 Device 1 1,019.00'1.000 in/hr Filtration over Surface area above 1,019.00' Excluded Surface area = 1,200 sf #3 Secondary 1,020.00'130.0' long + 3.0 '/' SideZ x 1.0' 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 Coef. (English) 2.69 2.72 2.75 2.85 2.98 3.08 3.20 3.28 3.31 3.30 3.31 3.32 MSE 24-hr 3 100-Year Rainfall=7.38"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 54HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Primary OutFlow Max=0.06 cfs @ 12.17 hrs HW=1,020.10' TW=0.00' (Dynamic Tailwater) 1=Culvert (Passes 0.06 cfs of 8.11 cfs potential flow) 2=Filtration (Exfiltration Controls 0.06 cfs) Secondary OutFlow Max=10.55 cfs @ 12.17 hrs HW=1,020.10' TW=0.00' (Dynamic Tailwater) 3=Broad-Crested Rectangular Weir (Weir Controls 10.55 cfs @ 0.84 fps) Pond 9P: South Filtration Trench Inflow Outflow Primary Secondary Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)11 10 9 8 7 6 5 4 3 2 1 0 Inflow Area=1.353 ac Peak Elev=1,020.10' Storage=2,355 cf 10.65 cfs 10.63 cfs 0.06 cfs 10.57 cfs MSE 24-hr 3 100-Year Rainfall=7.38"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 55HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Hydrograph for Pond 9P: South Filtration Trench Time (hours) Inflow (cfs) Storage (cubic-feet) Elevation (feet) Outflow (cfs) Primary (cfs) Secondary (cfs) 0.00 0.00 0 1,017.25 0.00 0.00 0.00 20.00 0.10 2,082 1,020.00 0.10 0.05 0.05 40.00 0.00 487 1,019.15 0.01 0.01 0.00 60.00 0.00 368 1,019.00 0.00 0.00 0.00 80.00 0.00 368 1,019.00 0.00 0.00 0.00 100.00 0.00 368 1,019.00 0.00 0.00 0.00 120.00 0.00 368 1,019.00 0.00 0.00 0.00 140.00 0.00 368 1,019.00 0.00 0.00 0.00 160.00 0.00 368 1,019.00 0.00 0.00 0.00 180.00 0.00 368 1,019.00 0.00 0.00 0.00 200.00 0.00 368 1,019.00 0.00 0.00 0.00 220.00 0.00 368 1,019.00 0.00 0.00 0.00 240.00 0.00 368 1,019.00 0.00 0.00 0.00 260.00 0.00 368 1,019.00 0.00 0.00 0.00 280.00 0.00 368 1,019.00 0.00 0.00 0.00 300.00 0.00 368 1,019.00 0.00 0.00 0.00 320.00 0.00 368 1,019.00 0.00 0.00 0.00 340.00 0.00 368 1,019.00 0.00 0.00 0.00 360.00 0.00 368 1,019.00 0.00 0.00 0.00 380.00 0.00 368 1,019.00 0.00 0.00 0.00 400.00 0.00 368 1,019.00 0.00 0.00 0.00 420.00 0.00 368 1,019.00 0.00 0.00 0.00 440.00 0.00 368 1,019.00 0.00 0.00 0.00 460.00 0.00 368 1,019.00 0.00 0.00 0.00 480.00 0.00 368 1,019.00 0.00 0.00 0.00 500.00 0.00 368 1,019.00 0.00 0.00 0.00 520.00 0.00 368 1,019.00 0.00 0.00 0.00 540.00 0.00 368 1,019.00 0.00 0.00 0.00 560.00 0.00 368 1,019.00 0.00 0.00 0.00 580.00 0.00 368 1,019.00 0.00 0.00 0.00 600.00 0.00 368 1,019.00 0.00 0.00 0.00 MSE 24-hr 3 100-Year Rainfall=7.38"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 56HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Stage-Area-Storage for Pond 9P: South Filtration Trench Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 1,017.25 600 0 1,017.30 600 10 1,017.35 600 21 1,017.40 600 31 1,017.45 600 42 1,017.50 600 53 1,017.55 600 63 1,017.60 600 74 1,017.65 600 84 1,017.70 600 95 1,017.75 600 105 1,017.80 600 115 1,017.85 600 126 1,017.90 600 136 1,017.95 600 147 1,018.00 600 158 1,018.05 600 168 1,018.10 600 179 1,018.15 600 189 1,018.20 600 200 1,018.25 600 210 1,018.30 600 220 1,018.35 600 231 1,018.40 600 241 1,018.45 600 252 1,018.50 600 263 1,018.55 600 273 1,018.60 600 284 1,018.65 600 294 1,018.70 600 305 1,018.75 600 315 1,018.80 600 325 1,018.85 600 336 1,018.90 600 346 1,018.95 600 357 1,019.00 1,200 368 1,019.05 1,311 400 1,019.10 1,423 439 1,019.15 1,534 483 1,019.20 1,646 532 1,019.25 1,757 587 1,019.30 1,868 648 1,019.35 1,980 714 1,019.40 2,091 786 1,019.45 2,203 863 1,019.50 2,314 946 1,019.55 2,423 1,034 1,019.60 2,531 1,128 1,019.65 2,640 1,228 1,019.70 2,748 1,332 1,019.75 2,857 1,442 1,019.80 2,966 1,558 Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 1,019.85 3,074 1,679 1,019.90 3,183 1,805 1,019.95 3,291 1,937 1,020.00 3,400 2,075 1,020.05 3,495 2,217 1,020.10 3,590 2,364 1,020.15 3,685 2,516 1,020.20 3,780 2,673 1,020.25 3,875 2,834 1,020.30 3,970 3,000 1,020.35 4,065 3,171 1,020.40 4,160 3,346 1,020.45 4,255 3,527 1,020.50 4,350 3,712 MSE 24-hr 3 100-Year Rainfall=7.38"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 57HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Summary for Pond 10P: West Existing Wetland [61] Hint: Exceeded Reach 10R outlet invert by 0.14' @ 14.39 hrs Inflow Area = 22.414 ac, 39.34% Impervious, Inflow Depth > 5.82" for 100-Year event Inflow = 14.83 cfs @ 12.20 hrs, Volume= 10.878 af Outflow = 7.31 cfs @ 14.39 hrs, Volume= 10.873 af, Atten= 51%, Lag= 131.7 min Primary = 7.31 cfs @ 14.39 hrs, Volume= 10.873 af Routed to Link 7L : TOTAL Routing by Dyn-Stor-Ind method, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs Starting Elev= 974.10' Surf.Area= 54,326 sf Storage= 5,411 cf Peak Elev= 974.84' @ 14.39 hrs Surf.Area= 57,524 sf Storage= 46,686 cf (41,275 cf above start) Plug-Flow detention time= 471.9 min calculated for 10.749 af (99% of inflow) Center-of-Mass det. time= 139.6 min ( 3,147.8 - 3,008.2 ) Volume Invert Avail.Storage Storage Description #1 974.00' 487,616 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 974.00 53,893 0 0 975.00 58,226 56,060 56,060 976.00 62,886 60,556 116,616 977.00 67,093 64,990 181,605 978.00 71,582 69,338 250,943 979.00 76,083 73,833 324,775 980.00 81,311 78,697 403,472 981.00 86,977 84,144 487,616 Device Routing Invert Outlet Devices #1 Primary 974.10'18.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads Primary OutFlow Max=7.31 cfs @ 14.39 hrs HW=974.84' TW=0.00' (Dynamic Tailwater) 1=Orifice/Grate (Orifice Controls 7.31 cfs @ 4.14 fps) MSE 24-hr 3 100-Year Rainfall=7.38"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 58HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Pond 10P: West Existing Wetland Inflow Primary Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Inflow Area=22.414 ac Peak Elev=974.84' Storage=46,686 cf 14.83 cfs 7.31 cfs MSE 24-hr 3 100-Year Rainfall=7.38"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 59HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Hydrograph for Pond 10P: West Existing Wetland Time (hours) Inflow (cfs) Storage (cubic-feet) Elevation (feet) Primary (cfs) 0.00 0.00 5,411 974.10 0.00 20.00 2.51 23,679 974.43 2.95 40.00 1.49 17,206 974.32 1.54 60.00 0.72 12,936 974.24 0.79 80.00 0.15 8,254 974.15 0.18 100.00 0.09 7,165 974.13 0.09 120.00 0.07 6,985 974.13 0.08 140.00 0.06 6,851 974.13 0.07 160.00 0.06 6,734 974.12 0.06 180.00 0.05 6,628 974.12 0.05 200.00 0.04 6,532 974.12 0.05 220.00 0.04 6,444 974.12 0.04 240.00 0.03 6,363 974.12 0.04 260.00 0.03 6,288 974.12 0.03 280.00 0.03 6,219 974.11 0.03 300.00 0.02 6,155 974.11 0.02 320.00 0.02 6,096 974.11 0.02 340.00 0.02 6,042 974.11 0.02 360.00 0.02 5,992 974.11 0.02 380.00 0.01 5,946 974.11 0.02 400.00 0.01 5,903 974.11 0.01 420.00 0.01 5,864 974.11 0.01 440.00 0.01 5,828 974.11 0.01 460.00 0.01 5,794 974.11 0.01 480.00 0.01 5,764 974.11 0.01 500.00 0.01 5,735 974.11 0.01 520.00 0.01 5,709 974.11 0.01 540.00 0.01 5,685 974.11 0.01 560.00 0.00 5,663 974.10 0.00 580.00 0.00 5,643 974.10 0.00 600.00 0.00 5,624 974.10 0.00 MSE 24-hr 3 100-Year Rainfall=7.38"PDRN Printed 7/3/2025Prepared by Alliant Engineering, Inc Page 60HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Stage-Area-Storage for Pond 10P: West Existing Wetland Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 974.00 53,893 0 974.10 54,326 5,411 974.20 54,760 10,865 974.30 55,193 16,363 974.40 55,626 21,904 974.50 56,060 27,488 974.60 56,493 33,116 974.70 56,926 38,787 974.80 57,359 44,501 974.90 57,793 50,259 975.00 58,226 56,060 975.10 58,692 61,905 975.20 59,158 67,798 975.30 59,624 73,737 975.40 60,090 79,723 975.50 60,556 85,755 975.60 61,022 91,834 975.70 61,488 97,959 975.80 61,954 104,131 975.90 62,420 110,350 976.00 62,886 116,616 976.10 63,307 122,925 976.20 63,727 129,277 976.30 64,148 135,671 976.40 64,569 142,106 976.50 64,990 148,584 976.60 65,410 155,104 976.70 65,831 161,666 976.80 66,252 168,271 976.90 66,672 174,917 977.00 67,093 181,605 977.10 67,542 188,337 977.20 67,991 195,113 977.30 68,440 201,935 977.40 68,889 208,801 977.50 69,338 215,713 977.60 69,786 222,669 977.70 70,235 229,670 977.80 70,684 236,716 977.90 71,133 243,807 978.00 71,582 250,943 978.10 72,032 258,123 978.20 72,482 265,349 978.30 72,932 272,620 978.40 73,382 279,935 978.50 73,833 287,296 978.60 74,283 294,702 978.70 74,733 302,153 978.80 75,183 309,648 978.90 75,633 317,189 979.00 76,083 324,775 979.10 76,606 332,409 Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 979.20 77,129 340,096 979.30 77,651 347,835 979.40 78,174 355,626 979.50 78,697 363,470 979.60 79,220 371,366 979.70 79,743 379,314 979.80 80,265 387,314 979.90 80,788 395,367 980.00 81,311 403,472 980.10 81,878 411,631 980.20 82,444 419,848 980.30 83,011 428,120 980.40 83,577 436,450 980.50 84,144 444,836 980.60 84,711 453,278 980.70 85,277 461,778 980.80 85,844 470,334 980.90 86,410 478,947 981.00 86,977 487,616 Project Information Calculator Version: Version 4: July 2020 Project Name:Pleasant View Pointe -Project Site + Pleasant View Dr. User Name / Company Name: Alliant Engineering Date: 7-3-2025 Project Description:Proposed subdivision + Peaceful Lane reconstruction + future Pleasant View Road with project future impervious surface addition Construction Permit?: No Site Information Retention Requirement (inches):1 Site's Zip Code: 55317 Annual Rainfall (inches):29.9 Phosphorus EMC (mg/l): 0.3 TSS EMC (mg/l): 54.5 Total Site Area Land Cover A Soils (acres) B Soils (acres) C Soils (acres) D Soils (acres) Total (acres) Forest/Open Space -Undisturbed, protected forest/open space or reforested land 4.229 4.229 Managed Turf -disturbed, graded for yards or other turf to be mowed/managed 5.866 5.866 Impervious Area (acres) 5.795 Total Area (acres) 15.89 Site Areas Routed to BMPs Land Cover A Soils (acres) B Soils (acres) C Soils (acres) D Soils (acres) Total (acres) Forest/Open Space -Undisturbed, protected forest/open space or reforested land 4.229 4.229 Managed Turf -disturbed, graded for yards or other turf to be mowed/managed 5.866 5.866 Impervious Area (acres) 5.795 Total Area (acres) 15.89 Summary Information Performance Goal Requirement Performance goal volume retention requirement: 21036 ft3 Volume removed by BMPs towards performance goal: 12735 ft³ Percent volume removed towards performance goal 61 % Annual Volume and Pollutant Load Reductions Post development annual runoff volume 16.1083 acre-ft Annual runoff volume removed by BMPs: 4.5558 acre-ft Percent annual runoff volume removed: 28 % Post development annual particulate P load:7.2294 lbs Annual particulate P removed by BMPs: 6.355 lbs Post development annual dissolved P load: 5.915 lbs Annual dissolved P removed by BMPs: 2.264 lbs Total P removed by BMPs 8.619 lbs Percent annual total phosphorus removed: 66 % Post development annual TSS load: 2387.9 lbs Annual TSS removed by BMPs:2227 lbs Percent annual TSS removed: 93 % BMP Summary Performance Goal Summary BMP Name BMP Volume Capacity (ft3) Volume Recieved (ft3) Volume Retained (ft3) Volume Outflow (ft3) Percent Retained (%) Wetland Filtration Shelf 8575 16451 8575 7876 52 West Filtration Basin 1453 1381 1381 0 100 Disconnected Impervious Direct to Constructed Wetland1311 2984 1311 1673 44 Disconnected - Untreated 0 0 0 0 0 West Disconnected Impervious (S4)1098 2479 1098 1381 44 South Disconnected Impervious (S9)370 795 370 425 47 South Filtration Trench 0 425 0 425 0 Constructed wetland 0 16451 0 16451 0 Annual Volume Summary BMP Name Volume From Direct Watershed (acre-ft) Volume From Upstream BMPs (acre-ft) Volume Retained (acre-ft) Volume outflow (acre-ft) Percent Retained (%) Wetland Filtration Shelf 0 12.6582 3.273 9.3852 26 West Filtration Basin 0 1.8217 0.5432 1.2785 30 Disconnected Impervious Direct to Constructed Wetland2.7321 0 0.329 2.4031 12 Disconnected - Untreated 0.1432 0 0 0.1432 0 West Disconnected Impervious (S4)2.1122 0 0.2905 1.8217 14 South Disconnected Impervious (S9)0.8657 0 0.1201 0.7456 14 South Filtration Trench 0 0.7457 0 0.7457 0 Constructed wetland 10.2551 2.4031 0 12.6582 0 Particulate Phosphorus Summary BMP Name Load From Direct Watershed (lbs) Load From Upstream BMPs (lbs) Load Retained (lbs) Outflow Load (lbs) Percent Retained (%) Wetland Filtration Shelf 0 3.357 2.8592 0.4978 85 West Filtration Basin 0 0.8176 0.7028 0.1148 86 Disconnected Impervious Direct to Constructed Wetland1.2262 0 0.1477 1.0785 12 Disconnected - Untreated 0.0643 0 0 0.0643 0 West Disconnected Impervious (S4)0.948 0 0.1304 0.8176 14 South Disconnected Impervious (S9)0.3885 0 0.0539 0.3346 14 South Filtration Trench 0 0.3346 0.1372 0.1974 41 Constructed wetland 4.6025 1.0785 2.324 3.357 41 Dissolved Phosphorus Summary BMP Name Load From Direct Watershed (lbs) Load From Upstream BMPs (lbs) Load Retained (lbs) Outflow Load (lbs) Percent Retained (%) Wetland Filtration Shelf 0 4.6481 1.7222 2.9259 37 West Filtration Basin 0 0.6689 0.2703 0.3986 40 Disconnected Impervious Direct to Constructed Wetland1.0032 0 0.1208 0.8824 12 Disconnected - Untreated 0.0526 0 0 0.0526 0 West Disconnected Impervious (S4)0.7756 0 0.1067 0.6689 14 South Disconnected Impervious (S9)0.3179 0 0.0441 0.2738 14 South Filtration Trench 0 0.2738 0 0.2738 0 Constructed wetland 3.7657 0.8824 0 4.6481 0 Total Phosphorus Summary BMP Name Load From Direct Watershed (lbs) Load From Upstream BMPs (lbs) Load Retained (lbs) Outflow Load (lbs) Percent Retained (%) Wetland Filtration Shelf 0 8.0051 4.5814 3.4237 61 West Filtration Basin 0 1.4865 0.9731 0.5134 63 Disconnected Impervious Direct to Constructed Wetland2.2294 0 0.2685 1.9609 12 Disconnected - Untreated 0.1169 0 0 0.1169 0 West Disconnected Impervious (S4)1.7236 0 0.2371 1.4865 14 South Disconnected Impervious (S9)0.7064 0 0.098 0.6084 14 South Filtration Trench 0 0.6084 0.1372 0.4712 20 Constructed wetland 8.3682 1.9609 2.324 8.0051 20 TSS Summary BMP Name Load From Direct Watershed (lbs) Load From Upstream BMPs (lbs) Load Retained (lbs) Outflow Load (lbs) Percent Retained (%) Wetland Filtration Shelf 0 800.76 682.02 118.74 85 West Filtration Basin 0 86.42 74.29 12.13 86 Disconnected Impervious Direct to Constructed Wetland405.01 0 291.02 113.99 72 Disconnected - Untreated 21.23 0 0 21.23 0 West Disconnected Impervious (S4)313.11 0 226.69 86.42 72 South Disconnected Impervious (S9)128.33 0 92.96 35.37 72 South Filtration Trench 0 35.37 26.53 8.84000000000002 75 Constructed wetland 1520.21 113.99 833.44 800.76 51 BMP Schematic Project Information Calculator Version: Version 4: July 2020 Project Name:Pleasant View Pointe -Project Site + Pleasant View Dr + Troendle User Name / Company Name:Alliant Engineering Date: 6-4-25 Project Description:Proposed subdivision + Peaceful Lane reconstruction + future Pleasant View Road with project future impervious surface addition + Existing Troendle Addition Construction Permit?: No Site Information Retention Requirement (inches):1 Site's Zip Code: 55317 Annual Rainfall (inches): 29.9 Phosphorus EMC (mg/l):0.3 TSS EMC (mg/l): 54.5 Total Site Area Land Cover A Soils (acres) B Soils (acres) C Soils (acres) D Soils (acres) Total (acres) Forest/Open Space -Undisturbed, protected forest/open space or reforested land 4.229 4.229 Managed Turf -disturbed, graded for yards or other turf to be mowed/managed 7.907 7.907 Impervious Area (acres) 7.398 Total Area (acres) 19.534 Site Areas Routed to BMPs Land Cover A Soils (acres) B Soils (acres) C Soils (acres) D Soils (acres) Total (acres) Forest/Open Space -Undisturbed, protected forest/open space or reforested land 4.229 4.229 Managed Turf -disturbed, graded for yards or other turf to be mowed/managed 7.907 7.907 Impervious Area (acres) 7.398 Total Area (acres) 19.534 Summary Information Performance Goal Requirement Performance goal volume retention requirement: 26855 ft3 Volume removed by BMPs towards performance goal: 12735 ft³ Percent volume removed towards performance goal 47 % Annual Volume and Pollutant Load Reductions Post development annual runoff volume 20.6676 acre-ft Annual runoff volume removed by BMPs: 5.038 acre-ft Percent annual runoff volume removed: 24 % Post development annual particulate P load:9.2756 lbs Annual particulate P removed by BMPs: 8.185 lbs Post development annual dissolved P load: 7.589 lbs Annual dissolved P removed by BMPs: 2.667 lbs Total P removed by BMPs 10.852 lbs Percent annual total phosphorus removed: 64 % Post development annual TSS load: 3063.8 lbs Annual TSS removed by BMPs:2844.5 lbs Percent annual TSS removed: 93 % BMP Summary Performance Goal Summary BMP Name BMP Volume Capacity (ft3) Volume Recieved (ft3) Volume Retained (ft3) Volume Outflow (ft3) Percent Retained (%) Wetland Filtration Shelf 8575 22269 8575 13694 39 West Filtration Basin 1453 1381 1381 0 100 Disconnected Impervious Direct to Constructed Wetland1311 2984 1311 1673 44 Disconnected - Untreated 0 0 0 0 0 West Disconnected Impervious (S4)1098 2479 1098 1381 44 South Disconnected Impervious (S9)370 795 370 425 47 South Filtration Trench 0 425 0 425 0 Constructed wetland 0 22269 0 22269 0 Annual Volume Summary BMP Name Volume From Direct Watershed (acre-ft) Volume From Upstream BMPs (acre-ft) Volume Retained (acre-ft) Volume outflow (acre-ft) Percent Retained (%) Wetland Filtration Shelf 0 17.2174 3.7552 13.4622 22 West Filtration Basin 0 1.8217 0.5432 1.2785 30 Disconnected Impervious Direct to Constructed Wetland2.7321 0 0.329 2.4031 12 Disconnected - Untreated 0.1432 0 0 0.1432 0 West Disconnected Impervious (S4)2.1122 0 0.2905 1.8217 14 South Disconnected Impervious (S9)0.8657 0 0.1201 0.7456 14 South Filtration Trench 0 0.7457 0 0.7457 0 Constructed wetland 14.8143 2.4031 0 17.2174 0 Particulate Phosphorus Summary BMP Name Load From Direct Watershed (lbs) Load From Upstream BMPs (lbs) Load Retained (lbs) Outflow Load (lbs) Percent Retained (%) Wetland Filtration Shelf 0 4.5661 3.8521 0.714 84 West Filtration Basin 0 0.8176 0.7028 0.1148 86 Disconnected Impervious Direct to Constructed Wetland1.2262 0 0.1477 1.0785 12 Disconnected - Untreated 0.0643 0 0 0.0643 0 West Disconnected Impervious (S4)0.948 0 0.1304 0.8176 14 South Disconnected Impervious (S9)0.3885 0 0.0539 0.3346 14 South Filtration Trench 0 0.3346 0.1372 0.1974 41 Constructed wetland 6.6487 1.0785 3.1611 4.5661 41 Dissolved Phosphorus Summary BMP Name Load From Direct Watershed (lbs) Load From Upstream BMPs (lbs) Load Retained (lbs) Outflow Load (lbs) Percent Retained (%) Wetland Filtration Shelf 0 6.3222 2.1253 4.1969 34 West Filtration Basin 0 0.6689 0.2703 0.3986 40 Disconnected Impervious Direct to Constructed Wetland1.0032 0 0.1208 0.8824 12 Disconnected - Untreated 0.0526 0 0 0.0526 0 West Disconnected Impervious (S4)0.7756 0 0.1067 0.6689 14 South Disconnected Impervious (S9)0.3179 0 0.0441 0.2738 14 South Filtration Trench 0 0.2738 0 0.2738 0 Constructed wetland 5.4398 0.8824 0 6.3222 0 Total Phosphorus Summary BMP Name Load From Direct Watershed (lbs) Load From Upstream BMPs (lbs) Load Retained (lbs) Outflow Load (lbs) Percent Retained (%) Wetland Filtration Shelf 0 10.8883 5.9774 4.9109 59 West Filtration Basin 0 1.4865 0.9731 0.5134 63 Disconnected Impervious Direct to Constructed Wetland2.2294 0 0.2685 1.9609 12 Disconnected - Untreated 0.1169 0 0 0.1169 0 West Disconnected Impervious (S4)1.7236 0 0.2371 1.4865 14 South Disconnected Impervious (S9)0.7064 0 0.098 0.6084 14 South Filtration Trench 0 0.6084 0.1372 0.4712 20 Constructed wetland 12.0885 1.9609 3.1611 10.8883 20 TSS Summary BMP Name Load From Direct Watershed (lbs) Load From Upstream BMPs (lbs) Load Retained (lbs) Outflow Load (lbs) Percent Retained (%) Wetland Filtration Shelf 0 1131.93 954.92 177.01 84 West Filtration Basin 0 86.42 74.29 12.13 86 Disconnected Impervious Direct to Constructed Wetland405.01 0 291.02 113.99 72 Disconnected - Untreated 21.23 0 0 21.23 0 West Disconnected Impervious (S4)313.11 0 226.69 86.42 72 South Disconnected Impervious (S9)128.33 0 92.96 35.37 72 South Filtration Trench 0 35.37 26.53 8.84000000000002 75 Constructed wetland 2196.07 113.99 1178.13 1131.93 51 BMP Schematic Project Information Calculator Version: Version 4: July 2020 Project Name:Pleasant View Pointe -Project Site + Pleasant View Dr + Troendle User Name / Company Name:Alliant Engineering Date: 7-3-25 Project Description:Proposed subdivision + Peaceful Lane reconstruction + future Pleasant View Road with project future impervious surface addition + Existing Troendle Addition Construction Permit?: No Site Information Retention Requirement (inches):1 Site's Zip Code: 55317 Annual Rainfall (inches): 29.9 Phosphorus EMC (mg/l):0.3 TSS EMC (mg/l): 54.5 Total Site Area Land Cover A Soils (acres) B Soils (acres) C Soils (acres) D Soils (acres) Total (acres) Forest/Open Space -Undisturbed, protected forest/open space or reforested land 4.229 4.229 Managed Turf -disturbed, graded for yards or other turf to be mowed/managed 7.907 7.907 Impervious Area (acres) 7.398 Total Area (acres) 19.534 Site Areas Routed to BMPs Land Cover A Soils (acres) B Soils (acres) C Soils (acres) D Soils (acres) Total (acres) Forest/Open Space -Undisturbed, protected forest/open space or reforested land 4.229 4.229 Managed Turf -disturbed, graded for yards or other turf to be mowed/managed 7.907 7.907 Impervious Area (acres) 7.398 Total Area (acres) 19.534 Summary Information Performance Goal Requirement Performance goal volume retention requirement: 26855 ft3 Volume removed by BMPs towards performance goal: 12735 ft³ Percent volume removed towards performance goal 47 % Annual Volume and Pollutant Load Reductions Post development annual runoff volume 20.6676 acre-ft Annual runoff volume removed by BMPs: 5.038 acre-ft Percent annual runoff volume removed: 24 % Post development annual particulate P load:9.2756 lbs Annual particulate P removed by BMPs: 8.185 lbs Post development annual dissolved P load: 7.589 lbs Annual dissolved P removed by BMPs: 2.667 lbs Total P removed by BMPs 10.852 lbs Percent annual total phosphorus removed: 64 % Post development annual TSS load: 3063.8 lbs Annual TSS removed by BMPs:2844.5 lbs Percent annual TSS removed: 93 % BMP Summary Performance Goal Summary BMP Name BMP Volume Capacity (ft3) Volume Recieved (ft3) Volume Retained (ft3) Volume Outflow (ft3) Percent Retained (%) Wetland Filtration Shelf 8575 22269 8575 13694 39 West Filtration Basin 1453 1381 1381 0 100 Disconnected Impervious Direct to Constructed Wetland1311 2984 1311 1673 44 Disconnected - Untreated 0 0 0 0 0 West Disconnected Impervious (S4)1098 2479 1098 1381 44 South Disconnected Impervious (S9)370 795 370 425 47 South Filtration Trench 0 425 0 425 0 Constructed wetland 0 22269 0 22269 0 Annual Volume Summary BMP Name Volume From Direct Watershed (acre-ft) Volume From Upstream BMPs (acre-ft) Volume Retained (acre-ft) Volume outflow (acre-ft) Percent Retained (%) Wetland Filtration Shelf 0 17.2174 3.7552 13.4622 22 West Filtration Basin 0 1.8217 0.5432 1.2785 30 Disconnected Impervious Direct to Constructed Wetland2.7321 0 0.329 2.4031 12 Disconnected - Untreated 0.1432 0 0 0.1432 0 West Disconnected Impervious (S4)2.1122 0 0.2905 1.8217 14 South Disconnected Impervious (S9)0.8657 0 0.1201 0.7456 14 South Filtration Trench 0 0.7457 0 0.7457 0 Constructed wetland 14.8143 2.4031 0 17.2174 0 Particulate Phosphorus Summary BMP Name Load From Direct Watershed (lbs) Load From Upstream BMPs (lbs) Load Retained (lbs) Outflow Load (lbs) Percent Retained (%) Wetland Filtration Shelf 0 4.5661 3.8521 0.714 84 West Filtration Basin 0 0.8176 0.7028 0.1148 86 Disconnected Impervious Direct to Constructed Wetland1.2262 0 0.1477 1.0785 12 Disconnected - Untreated 0.0643 0 0 0.0643 0 West Disconnected Impervious (S4)0.948 0 0.1304 0.8176 14 South Disconnected Impervious (S9)0.3885 0 0.0539 0.3346 14 South Filtration Trench 0 0.3346 0.1372 0.1974 41 Constructed wetland 6.6487 1.0785 3.1611 4.5661 41 Dissolved Phosphorus Summary BMP Name Load From Direct Watershed (lbs) Load From Upstream BMPs (lbs) Load Retained (lbs) Outflow Load (lbs) Percent Retained (%) Wetland Filtration Shelf 0 6.3222 2.1253 4.1969 34 West Filtration Basin 0 0.6689 0.2703 0.3986 40 Disconnected Impervious Direct to Constructed Wetland1.0032 0 0.1208 0.8824 12 Disconnected - Untreated 0.0526 0 0 0.0526 0 West Disconnected Impervious (S4)0.7756 0 0.1067 0.6689 14 South Disconnected Impervious (S9)0.3179 0 0.0441 0.2738 14 South Filtration Trench 0 0.2738 0 0.2738 0 Constructed wetland 5.4398 0.8824 0 6.3222 0 Total Phosphorus Summary BMP Name Load From Direct Watershed (lbs) Load From Upstream BMPs (lbs) Load Retained (lbs) Outflow Load (lbs) Percent Retained (%) Wetland Filtration Shelf 0 10.8883 5.9774 4.9109 59 West Filtration Basin 0 1.4865 0.9731 0.5134 63 Disconnected Impervious Direct to Constructed Wetland2.2294 0 0.2685 1.9609 12 Disconnected - Untreated 0.1169 0 0 0.1169 0 West Disconnected Impervious (S4)1.7236 0 0.2371 1.4865 14 South Disconnected Impervious (S9)0.7064 0 0.098 0.6084 14 South Filtration Trench 0 0.6084 0.1372 0.4712 20 Constructed wetland 12.0885 1.9609 3.1611 10.8883 20 TSS Summary BMP Name Load From Direct Watershed (lbs) Load From Upstream BMPs (lbs) Load Retained (lbs) Outflow Load (lbs) Percent Retained (%) Wetland Filtration Shelf 0 1131.93 954.92 177.01 84 West Filtration Basin 0 86.42 74.29 12.13 86 Disconnected Impervious Direct to Constructed Wetland405.01 0 291.02 113.99 72 Disconnected - Untreated 21.23 0 0 21.23 0 West Disconnected Impervious (S4)313.11 0 226.69 86.42 72 South Disconnected Impervious (S9)128.33 0 92.96 35.37 72 South Filtration Trench 0 35.37 26.53 8.84000000000002 75 Constructed wetland 2196.07 113.99 1178.13 1131.93 51 BMP Schematic STORM SEWER DESIGN WORKSHEET - POST-DEVELOPMENT CONDITIONSPROJECT NAME: Pleasant View Pointe ALLIANT ENGINEERING, INC.PROJECT NUMBER: 4000320PREPARED BY: MPRREVISION DATE: 7-3-25 ``DESIGN STORM FREQUENCY = 10 YEARSIMP RUNOFF INTENSITY P. DIA. P. SLOPE P. TYPE MANNING'S P. CAP. P. VELOCITY PIPE CAP. OVER FROM TO RIM COVER STR. CAST BUILDFROM TO TOTAL IMPERVIOUS INCR. CUM. % C INCR. CUM. PIPE CUM. i INCR. CUM. D [IN] S [FT/FT] n Q [CFS] MAX [FT/S] LENGTH [FT] Q [CFS] INVERT INVERT ELEV [FT] TYPE TYPE[FT]PE 106 OCS 105 0.00 0.00 15 -0.0567 RCP 35.2 0.000 992.00 994.00 15" PEOCS 105 MH 104 0.00 0.00 15 0.0050 RCP 56.2 0.000 990.90 990.62 1000.00 7.85 72" OCS 9.10MH 104 MH 103 0.00 0.00 15 0.0120 RCP 205.1 0.000 990.52 988.06 1004.18 12.41 48" R-1642 13.66MH 103 MH 102 0.00 0.00 15 0.0050 HDPP 266.2 0.000 987.96 986.63 999.96 10.75 48" R-1642 12.00MH 102 MH 101 0.00 0.00 18 0.1440 HDPE 53.9 0.000 986.40 978.64 996.02 8.12 48" R-1643 9.62MH 101 FES 100 0.00 0.00 24 0.0046 RCP 0.013 15.34 4.88 24.2 15.343 974.81 974.70 982.02 5.21 48" R-1644 7.21974.10EXMH 1 EXMH 3 111200 56544 2.55 2.55 0.51 0.56 1.42 1.42 15.00 15.00 4.40 6.25 6.25 15 0.0169 RCP 0.013 8.40 6.84 159.1 2.150 1009.17 1006.48 1017.00 6.58 27 R-4342 7.83Existing PipeCBMH2EXMH3 33064 7777 0.76 0.76 0.24 0.36 0.28 0.28 12.00 12.00 4.75 1.32 1.32 15 0.0072 RCP 0.013 5.48 4.47 26.8 4.1661006.671006.48 1010.67 2.75 2'x3' R-3067-V 4.00EXMH 3 CBMH 202 0 0 0.00 3.31 0.00 0.20 0.00 1.70 0.39 15.39 4.36 0.00 7.40 15 0.0250 RCP 0.013 10.21 8.32 41.2 2.816 1006.48 1005.45 1010.77 3.04 48" R-1642 10.57Ex MH CB 211CBMH 209 36460 15686 0.84 0.84 0.43 0.50 0.42 0.42 10.00 10.00 5.04 2.11 2.11 15 0.0050 RCP 0.013 4.57 3.72 31.0 2.4551020.321020.17 1024.32 2.75 2'x3' R-3067-V 4.00CB 210CBMH 209 42120 12636 0.97 0.97 0.30 0.41 0.40 0.40 10.00 10.00 5.04 2.00 2.00 15 0.0050 RCP 0.013 4.57 3.72 164.5 2.5711012.151011.33 1015.40 2.00 27" R-4342 3.25CBMH 209 CBMH 208 34797 15009 0.80 2.60 0.43 0.50 0.40 1.22 0.74 10.74 4.93 1.98 5.99 15 0.0222 RCP 0.013 9.61 7.83 206.3 3.620 1011.33 1006.76 1024.39 11.81 48" R-3067-V 13.06CBMH 208 MH 206 16308 6827 0.37 2.98 0.42 0.49 0.18 1.40 0.44 11.18 4.86 0.90 6.82 15 0.0313 RCP 0.013 11.43 9.31 41.4 4.613 1006.76 1005.46 1010.76 2.75 48" R-3067-V 4.00CB 207MH 206 19168 7716 0.44 0.44 0.40 0.48 0.21 0.21 10.00 10.00 5.04 1.07 1.07 15 0.0050 RCP 0.013 4.57 3.72 47.1 3.5001004.781004.54 1008.78 2.75 2'x3' R-3067-V 4.00MH 206 CBMH 204 0 0 0.00 3.42 0.00 0.20 0.00 1.61 0.07 11.25 4.85 0.00 7.83 18 0.0060 RCP 0.013 8.14 4.60 72.4 0.307 1004.29 1003.86 1009.47 3.68 48" R-1642 5.18CB 205CBMH 204 10199 4979 0.23 0.23 0.49 0.54 0.13 0.13 8.00 8.00 5.39 0.68 0.68 15 0.0050 RCP 0.013 4.57 3.72 31.0 3.8841004.741004.59 1008.74 2.75 2'x3' R-3067-V 4.00CBMH 204 CBMH 202 16305 6085 0.37 4.03 0.37 0.46 0.17 1.91 0.26 11.51 4.82 0.83 9.21 18 0.0080 RCP 0.013 9.40 5.32 89.1 0.181 1003.86 1003.15 1008.74 3.38 48" R-3067-V 4.88CB203CBMH 202 17905 5372 0.41 0.41 0.30 0.41 0.17 0.17 10.00 10.00 5.04 0.85 0.85 15 0.0050 RCP 0.013 4.57 3.72 94.7 3.7191005.471005.00 1008.90 2.18 27" R-4342 3.43CBMH 202CBMH 201 31951 10017 0.73 8.48 0.31 0.42 0.31 4.09 0.08 15.47 4.35 1.34 17.79 18 0.0287 RCP 0.013 17.80 10.07148.60.0101000.57996.30 1009.50 7.43 48" R-3067-V 12.934 FT SUMPCBMH 201 FES 2000 0 0.00 8.48 0.00 0.20 0.00 4.09 0.25 15.72 4.33 0.00 17.68 27 0.0041 RCP 0.013 19.83 4.9946.72.146994.19994.00 1000.00 3.56 48" R-4342 5.81FES 200 POND8.48 4.09994.0027" FESCB 302CBMH 301 23682 11891 0.54 0.54 0.50 0.55 0.30 0.30 10.00 10.00 5.04 1.51 1.51 15 0.0050 RCP 0.013 4.57 3.7231.03.057995.13994.98 999.13 2.75 2'x3' R-3067-V 4.00CBMH 301 FES 30018066 7762 0.41 0.96 0.43 0.50 0.21 0.51 0.14 10.14 5.02 1.04 2.55 15 0.0050 RCP 0.013 4.57 3.7243.52.022994.22994.00 999.13 3.66 48" R-3067-V 8.914 FT SUMPFES 300 POND0.96 0.51994.0015" FES ADS 700MH701 6 0.0050 PVC 0.012279.60.0001017.481016.08 1021.00 3.02 24" 3.52MH701 CBMH 70212 0.0734 HDPP 0.013189.40.0001015.501001.60 1022.00 5.50 48 6.50CBMH 702 Ex Pipe1000.801000.80 1005.60 4.80 48 4.80OCS 501 MH 102 15 0.0455 RCP 0.021 25.4 992.00 990.84 998.00ADS 602ADS 601 40488 12146 0.93 0.93 0.30 0.41 0.38 0.38 10.00 10.00 5.04 1.92 1.92 8 0.2750 HDPE 0.012 6.87 19.6773.44.9451017.00996.80 1020.00 18" 3.00ADS 601 PE 6000 12146 0.00 0.93 0.00 0.20 0.00 0.38 0.06 10.06 5.03 0.00 1.92 10 0.0070 HDPE 0.012 1.99 3.6413.70.070995.10995.00 999.70 30" 4.60PE 6000.93 0.38995.0010" PEIDF Curve Carver County 10-yr i = -1.567ln(x) + 8.6456Q [CFS]MH/CB AREA [AC] TIME OF CONC. [MIN]AREA [SF] A*C 123 7 5 1 2 3 4 5 67 8 9 10 11 12 13 6 BLOCK 2BLOCK 2BLOCK 1 BLOCK 1 1000' Shoreland District Boundary STORMWATER WETLAND/FILTRATION NWL:994.0 100 YEAR HWL:999.57 PEACEFUL LANEPEACEFUL LANE4 NEZ PERCE DRIVE PEACEFUL LANEFILTRATION BASIN 2 100 YEAR HWL:997.98 FILTRATION TRENCH 100 YEAR HWL:1020.10 203S CB 203 210S CB 210 1P CB 210 2P CB 203 Routing Diagram for PDRN - Low Point Rear Yard Prepared by Alliant Engineering, Inc, Printed 6/3/2025 HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Subcat Reach Pond Link Low Point CB Analysis PDRN - Low Point Rear Yard Printed 6/3/2025Prepared by Alliant Engineering, Inc Page 2HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Area Listing (all nodes) Area (acres) CN Description (subcatchment-numbers) 0.965 80 >75% Grass cover, Good, HSG D (203S, 210S) 0.413 98 Unconnected pavement, HSG D (203S, 210S) Low Point CB Analysis MSE 24-hr 3 100-Year Rainfall=7.38"PDRN - Low Point Rear Yard Printed 6/3/2025Prepared by Alliant Engineering, Inc Page 3HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Time span=0.00-600.00 hrs, dt=0.01 hrs, 60001 points Runoff by SCS TR-20 method, UH=SCS, Weighted-Q Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method Runoff Area=17,905 sf 30.00% Impervious Runoff Depth=5.67"Subcatchment 203S: CB 203 Tc=10.0 min CN=WQ Runoff=3.37 cfs 0.194 af Runoff Area=42,120 sf 30.00% Impervious Runoff Depth=5.67"Subcatchment 210S: CB 210 Tc=10.0 min UI Adjusted CN=WQ Runoff=7.93 cfs 0.457 af Peak Elev=1,015.99' Storage=55 cf Inflow=7.93 cfs 0.457 afPond 1P: CB 210 Outflow=7.89 cfs 0.457 af Peak Elev=1,009.23' Storage=29 cf Inflow=3.37 cfs 0.194 afPond 2P: CB 203 Outflow=3.37 cfs 0.194 af Low Point CB Analysis MSE 24-hr 3 100-Year Rainfall=7.38"PDRN - Low Point Rear Yard Printed 6/3/2025Prepared by Alliant Engineering, Inc Page 4HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment 203S: CB 203 Runoff = 3.37 cfs @ 12.17 hrs, Volume= 0.194 af, Depth= 5.67" Routed to Pond 2P : CB 203 Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 100-Year Rainfall=7.38" Area (sf) CN Description 5,372 98 Unconnected pavement, HSG D 12,533 80 >75% Grass cover, Good, HSG D 17,905 Weighted Average 12,533 70.00% Pervious Area 5,372 30.00% Impervious Area 5,372 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Subcatchment 203S: CB 203 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)3 2 1 0 MSE 24-hr 3 100-Year Rainfall=7.38" Runoff Area=17,905 sf Runoff Volume=0.194 af Runoff Depth=5.67" Tc=10.0 min CN=WQ 3.37 cfs Low Point CB Analysis MSE 24-hr 3 100-Year Rainfall=7.38"PDRN - Low Point Rear Yard Printed 6/3/2025Prepared by Alliant Engineering, Inc Page 5HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment 210S: CB 210 Runoff = 7.93 cfs @ 12.17 hrs, Volume= 0.457 af, Depth= 5.67" Routed to Pond 1P : CB 210 Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs MSE 24-hr 3 100-Year Rainfall=7.38" Area (sf) CN Adj Description 12,636 98 98 Unconnected pavement, HSG D 29,484 80 80 >75% Grass cover, Good, HSG D 42,120 Weighted Average 29,484 70.00% Pervious Area 12,636 30.00% Impervious Area 12,636 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Subcatchment 210S: CB 210 Runoff Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)8 7 6 5 4 3 2 1 0 MSE 24-hr 3 100-Year Rainfall=7.38" Runoff Area=42,120 sf Runoff Volume=0.457 af Runoff Depth=5.67" Tc=10.0 min UI Adjusted CN=WQ 7.93 cfs Low Point CB Analysis MSE 24-hr 3 100-Year Rainfall=7.38"PDRN - Low Point Rear Yard Printed 6/3/2025Prepared by Alliant Engineering, Inc Page 6HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Summary for Pond 1P: CB 210 Inflow Area = 0.967 ac, 30.00% Impervious, Inflow Depth = 5.67" for 100-Year event Inflow = 7.93 cfs @ 12.17 hrs, Volume= 0.457 af Outflow = 7.89 cfs @ 12.18 hrs, Volume= 0.457 af, Atten= 1%, Lag= 0.4 min Primary = 7.89 cfs @ 12.18 hrs, Volume= 0.457 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs Peak Elev= 1,015.99' @ 12.18 hrs Surf.Area= 184 sf Storage= 55 cf Plug-Flow detention time= 0.1 min calculated for 0.457 af (100% of inflow) Center-of-Mass det. time= 0.1 min ( 774.1 - 774.0 ) Volume Invert Avail.Storage Storage Description #1 1,015.40' 2,071 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 1,015.40 3 0 0 1,016.00 187 57 57 1,018.00 1,827 2,014 2,071 Device Routing Invert Outlet Devices #1 Primary 1,012.15'15.0" Round Culvert L= 163.6' RCP, square edge headwall, Ke= 0.500 Inlet / Outlet Invert= 1,012.15' / 1,011.33' S= 0.0050 '/' Cc= 0.900 n= 0.013 Concrete pipe, bends & connections, Flow Area= 1.23 sf #2 Device 1 1,015.40'21.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads Primary OutFlow Max=7.89 cfs @ 12.18 hrs HW=1,015.99' (Free Discharge) 1=Culvert (Barrel Controls 7.89 cfs @ 6.43 fps) 2=Orifice/Grate (Passes 7.89 cfs of 8.12 cfs potential flow) Low Point CB Analysis MSE 24-hr 3 100-Year Rainfall=7.38"PDRN - Low Point Rear Yard Printed 6/3/2025Prepared by Alliant Engineering, Inc Page 7HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Pond 1P: CB 210 Inflow Primary Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)8 7 6 5 4 3 2 1 0 Inflow Area=0.967 ac Peak Elev=1,015.99' Storage=55 cf 7.93 cfs 7.89 cfs Low Point CB Analysis MSE 24-hr 3 100-Year Rainfall=7.38"PDRN - Low Point Rear Yard Printed 6/3/2025Prepared by Alliant Engineering, Inc Page 8HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Summary for Pond 2P: CB 203 Inflow Area = 0.411 ac, 30.00% Impervious, Inflow Depth = 5.67" for 100-Year event Inflow = 3.37 cfs @ 12.17 hrs, Volume= 0.194 af Outflow = 3.37 cfs @ 12.18 hrs, Volume= 0.194 af, Atten= 0%, Lag= 0.2 min Primary = 3.37 cfs @ 12.18 hrs, Volume= 0.194 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-600.00 hrs, dt= 0.01 hrs Peak Elev= 1,009.23' @ 12.18 hrs Surf.Area= 174 sf Storage= 29 cf Plug-Flow detention time= 0.1 min calculated for 0.194 af (100% of inflow) Center-of-Mass det. time= 0.1 min ( 774.1 - 774.0 ) Volume Invert Avail.Storage Storage Description #1 1,008.90' 318 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 1,008.90 3 0 0 1,010.00 576 318 318 Device Routing Invert Outlet Devices #1 Primary 1,005.70'15.0" Round Culvert L= 94.7' RCP, mitered to conform to fill, Ke= 0.700 Inlet / Outlet Invert= 1,005.70' / 1,005.00' S= 0.0074 '/' Cc= 0.900 n= 0.013 Concrete pipe, bends & connections, Flow Area= 1.23 sf #2 Device 1 1,008.90'21.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads Primary OutFlow Max=3.36 cfs @ 12.18 hrs HW=1,009.23' (Free Discharge) 1=Culvert (Passes 3.36 cfs of 8.60 cfs potential flow) 2=Orifice/Grate (Weir Controls 3.36 cfs @ 1.87 fps) Low Point CB Analysis MSE 24-hr 3 100-Year Rainfall=7.38"PDRN - Low Point Rear Yard Printed 6/3/2025Prepared by Alliant Engineering, Inc Page 9HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC Pond 2P: CB 203 Inflow Primary Hydrograph Time (hours) 600550500450400350300250200150100500Flow (cfs)3 2 1 0 Inflow Area=0.411 ac Peak Elev=1,009.23' Storage=29 cf 3.37 cfs 3.37 cfs Low Point CB Analysis Table of ContentsPDRN - Low Point Rear Yard Printed 6/3/2025Prepared by Alliant Engineering, Inc HydroCAD® 10.20-5c s/n 01427 © 2023 HydroCAD Software Solutions LLC TABLE OF CONTENTS Project Reports 1 Routing Diagram 2 Area Listing (all nodes) 100-Year Event 3 Node Listing 4 Subcat 203S: CB 203 5 Subcat 210S: CB 210 6 Pond 1P: CB 210 8 Pond 2P: CB 203 Hydraulic Analysis Report Project Data Project Title: Pleasant View Pointe Designer: Ben Palazzolo Project Date: Thursday, July 3, 2025 Project Units: U.S. Customary Units Notes: Spread Calculation for CB 302 Curb and Gutter Analysis: CB 302 Notes: Gutter Input Parameters Longitudinal Slope of Road: 0.0000 ft/ft Cross-Slope of Pavement: 0.0200 ft/ft Uniform Gutter Geometry Manning's n: 0.0150 Gutter Width: 1.5000 ft Gutter Result Parameters Design Flow: 1.5100 cfs Gutter Result Parameters Width of Spread: 8.7797 ft Gutter Depression: 0.0000 in Area of Flow: 0.7708 ft^2 Eo (Gutter Flow to Total Flow): 0.3936 Gutter Depth at Curb: 2.1071 in Inlet Input Parameters Inlet Location: Inlet in Sag Percent Clogging: 0.0000 % Inlet Type: Equal-length Combo Grate Type: Curved vane Grate Width: 1.5000 ft Grate Length: 3.0000 ft Length of Inlet: 3.0000 ft Curb opening height: 6.0000 in Local Depression: 2.0000 in Inlet Result Parameters Perimeter: 6.0000 ft Effective Perimeter: 6.0000 ft Area: 3.5750 ft^2 Effective Area: 3.5750 ft^2 Depth at center of grate: 0.1916 ft Computed Width of Spread at Sag: 10.3316 ft Flow type: Weir Flow Efficiency: 1.0000 BORING # AND REPORT GROUND WATER Estimated LFE LFE TO GROUNDWATERDISTANCE TO BMP HWLALLOWABLE DISTANCE TO GROUNDWATER PER APPENDIX J1J1 ResultsFiltration Trench1080 Lake Lucy Rd ST-5 989.4 1000.2 10.8 109.08 4.5 No Further Evaluation1060 Lake Lucy Rd ST-5 989.4 1003.2 13.8 94.78 3 No Further Evaluation1040 Lake Lucy Rd ST-5 989.4 1005.6 16.2 76.15 2.2 No Further Evaluation 67 File Location: X:\4000320-00\001\30 Exhibits\Riley Purgatory J1 Exhibit.dwg Plotted By: Ben Palazzolo on July 3, 2025 at 11:10:53 AM PLEASANT VIEW POINTE - APPENDIX J1 ASSESSMENT File Location: X:\4000320-00\001\30 Exhibits\Riley Purgatory J1 Exhibit.dwg Plotted By: Ben Palazzolo on July 3, 2025 at 11:10:53 AM BORING # AND REPORT GROUND WATER Estimated LFE LFE TO GROUNDWATERDISTANCE TO BMP HWLALLOWABLE DISTANCE TO GROUNDWATER PER APPENDIX J1J1 ResultsFiltration Trench1080 Lake Lucy Rd ST-5 989.4 1000.2 10.8 109.08 4.5 No Further Evaluation1060 Lake Lucy Rd ST-5 989.4 1003.2 13.8 94.78 3 No Further Evaluation1040 Lake Lucy Rd ST-5 989.4 1005.6 16.2 76.15 2.2 No Further Evaluation Riley‐Purgatory‐Bluff Creek Watershed District Rules August 8, 2018 51 Appendix J1 – Low‐Floor Elevation Assessment Overview of Lowest Floor Issue There seems to be two reasons for establishing a minimum lowest floor elevation in the vicinity of a pond – to prevent flooding of the structure by surface water and to prevent seepage or damage from uplift pressures that could result from a rise in the water table elevation. The first reason (direct flooding) can easily be established with knowledge of the maximum flood elevation of a pond (or the 100‐year elevation, if this is used) and ground surface topography. The second reason (a rise in the water table due to increased pond elevations) is not so straight forward. This second area is the subject of this memo. When a formerly dry pond becomes wet (or when a wet pond’s water elevation increases) due to a storm event, downward seepage of the ponded water begins. The rate of seepage through the bottom of the pond is dependent upon: 1) The elevation of the water surface above the pond bottom 2) The soil type at the bottom of the pond (i.e. the pond bottom’s thickness and permeability) 3) The type of soil underneath the pond (e.g., clay, silt, sand, gravel) 4) The degree of saturation of the soils beneath the pond 5) The depth to the water table In general, higher seepage through the bottom of the pond will occur when the water surface elevation is high, the pond’s bottom sediments are thin and/or sandy, the soils underneath the pond are permeable (such as sand or gravel), the soils underneath the pond have a high moisture content (i.e., they are at field capacity or higher), and the water table is well below the bottom of the pond (i.e. the soils are freely draining). Higher seepage rates through the bottom of the pond will cause the water table elevation to rise by creating a “mounding condition” below the pond. How high and how widespread the water table mound becomes are contributing factors to whether or not basements will be affected. However, the single most important factor that will determine if seepage from a pond will cause wet basement problems is the depth to the water table, below the basement. The magnitude and extent of the groundwater mounding conditions is also contingent upon the aquifer’s transmissivity (aquifer permeability multiplied by aquifer thickness), the specific yield of the aquifer materials, and the duration of the high water levels in the pond. In general, thicker aquifers with higher permeability will experience less mounding than thinner aquifers of lower permeability. Perched aquifers (i.e. groundwater zones less than about 10 feet that overlie extensive clay layers) typically experience the greatest amount of mounding. Riley‐Purgatory‐Bluff Creek Watershed District Rules August 8, 2018 52 Overview of Evaluation Method All of the combinations of settings, pond configurations, aquifer parameters, and distances from ponds cannot be anticipated beforehand in coming up with a method to quickly evaluate whether or not a variance to the minimum floor elevation ordinance should be considered. However, by making some generalities, the most commonly encountered situations can be evaluated. This is the approach taken here. A groundwater flow model of a “typical” pond and aquifer setting was developed. Aquifer parameters and pond elevations were varied and the resulting water table mounding conditions were simulated. The following conditions were evaluated: 1. Pond elevation increases of 2 feet, 4 feet, and 6 feet above normal or dry conditions 2. Depth to the water table (before flooding) of 3 feet (to represent conditions of 3 feet or less) and 10 feet (to represent conditions where the depth to the water table is greater than 3 feet). The purpose of simulating these two conditions is that with shallow water tables, the rate of infiltration is substantially reduced as the groundwater mound rises into the pond. For deeper aquifer conditions, the pond bottom is always above the water table and the depth to the water table has no bearing on the seepage rate. 3. Three aquifer conditions: clay or perched aquifers (transmissivities of 7 ft2/day and specific yield values of 0.1); silt aquifers (transmissivity of 70 ft2/day and specific yield values of 0.2) and sand and gravel aquifers (transmissivities of 2000 ft2/day and specific yield values of 0.2). 4. Pond bottom sediment thickness of 1 feet and bottom sediment hydraulic conductivity of 1 ft/day. 5. Instantaneous occurrence of a flood condition in the pond, which lasts for 25 days, followed by instantaneous reduction to normal conditions. The purpose of using this condition is that the effects of aquifer storage (specific yield) are taken into account. A duration of 25 days was selected as being a reasonable time period of flood conditions. 6. Increases in the water table elevation were recorded at several distances between 5 feet and 200 feet from the pond. The maximum rise during the modeled period was selected for plotting. The U.S. Geological Survey’s groundwater modeling code, MODFLOW, was used for this analysis. How to Determine if a Variance is Warranted In order to determine if a proposed lowest floor elevation is acceptable, the following need to be known: 1. Depth to the water table and an estimation of the water table’s seasonally high elevation. Riley‐Purgatory‐Bluff Creek Watershed District Rules August 8, 2018 53 2. Type of aquifer materials – e.g., clay, silt, sand, gravel 3. Information as to whether or not the water table is perched or is part of a deeper, thicker aquifer system. 4. An estimate of the flood elevation of the pond. 5. The distance of the proposed floor to the pond. Depth to the water table and the type of aquifer material needs to be determined through the installation of soil borings. The other information should be estimated from other sources. Once this information is obtained, the minimum depth to the water table from the bottom of the proposed floor slab can be determined from one of six plots, attached to this memorandum. Which of the six plots to use depends on the depth of the water table with respect to the pond’s bottom and the type of aquifer material (e.g., clay, silt, sand, gravel). The following steps should be used: 1. Determine the closest distance of the proposed floor to the pond (if the pond size increases during flooding, the distance should be from the flooded perimeter of the pond to the proposed floor). 2. Using Plot 1, determine the minimum permissible depth to the water table for the specified distance from the pond. If the actual depth to the water table (see discussion below for determining this) is greater than the value on Plot 1, no further evaluation is necessary – the floor is sufficiently high with respect to the water table that the water table will not reach the bottom of the slab, regardless of the soil type or transmissivity. If the depth to the water table is less than the value from Plot 1, further evaluation is necessary. 3. If the soil type of the aquifer, below the water table, is mostly clay OR if the aquifer is perched (a continuous clay layer is less than 5 feet below the water table), Plot 2 must be used. The appropriate pond level increase (2, 4, or 6 feet) for flood conditions must be used in Plot 2 to find the minimum permissible depth to the water table. If the depth to the water table from Plot 2 is less than the actual depth to the water table, the proposed floor elevation is too low and must be raised to equal the value from Plot 2. 4. If the soil type of the aquifer is mostly silt AND the pond bottom is 3 feet or less above the water table, Plot 3 should be used. 5. If the soil type of the aquifer is mostly sand or gravel AND the pond bottom is 3 feet or less above the water table, Plot 4 should be used. 6. If the soil type of the aquifer is mostly silt AND the pond bottom is 3 feet or more above the water table, Plot 5 should be used. Riley‐Purgatory‐Bluff Creek Watershed District Rules August 8, 2018 54 7. If the soil type of the aquifer is mostly sand or gravel AND the pond bottom is 3 feet or more above the water table, Plot 5 should be used. The values from the plots are guidelines, based on typical conditions. If the plots indicate the proposed floor elevation is too low, additional analyses and data collection could be pursued by the applicant. These additional analyses could include additional soil borings, long‐term monitoring of piezometers, or more sophisticated modeling. Determining Depth to the Water Table If a variance to a lowest floor elevation ordinance is to be considered, the depth to the water table at the location in question must be known. Without this knowledge, there cannot be a technical basis for approving a variance. Furthermore, the applicant should demonstrate that the measured water‐table elevation is both representative of conditions over the entire floor area and is representative of values typical for seasonally high conditions (e.g. spring conditions). A suggested requirement for collecting this information is the following: 1. A minimum of two soil borings must be installed at or near the perimeter of the lowest floor. At least one of these borings must be where the floor is closest to the nearest pond. 2. Soil borings must extend to a depth of at least 7 feet below the water table. The borings must be left open for a time sufficient to determine the stabilized water level in the borehole. The water level must be measured with reference to a known bench mark that can relate the water table elevation to the proposed floor elevation. Soils at or immediately below the water table must be sampled and texturally classified using an approved classification method. Water levels measured during dry summer months or during the winter may be lower than water levels during the spring. The applicant should be required to make an effort to determine the likely amount of seasonal fluctuation in the water table in the area. Water level records from wells completed in the area could be used. If information is unavailable, the applicant should be required to add a value to the measured water table elevation. One suggestion would be to assume 25% of the total annual precipitation (29 inches), divided by the average effective porosity for non‐cohesive soils (0.3), which is: (29 inches/4) x (1 foot/12 inches)/0.3 = 2 feet If the seasonally adjusted maximum water‐table elevation is eight (8) feet or below the bottom of the slab of the lowest floor, it is unlikely that temporary flood conditions in the pond will cause the water table to rise to the level of the floor.6 Determining Soil Type at the Water Table 6 This assumes that the pond level begins to return to normal within about 30 days and the pond level’s increase is not greater than 6 feet. Riley‐Purgatory‐Bluff Creek Watershed District Rules August 8, 2018 55 The textural classification from the soil borings will be necessary for determining the expected rise in the water table caused by an increase in pond elevation. At a minimum, the soil should be classified as one of the following: 1. Sandy or gravely soils – consisting of predominantly sand or gravel, with minor amounts of silt and clay 2. Silty soils – consisting predominantly of silt 3. Clayey soils – consisting predominantly of clay. 56 Riley‐Purgatory‐Bluff Creek Watershed District Rules August 8, 2018 57 Riley‐Purgatory‐Bluff Creek Watershed District Rules August 8, 2018 58 Riley‐Purgatory‐Bluff Creek Watershed District Rules August 8, 2018 59 Riley‐Purgatory‐Bluff Creek Watershed District Rules August 8, 2018 60 Riley‐Purgatory‐Bluff Creek Watershed District Rules August 8, 2018 61 Riley‐Purgatory‐Bluff Creek Watershed District Rules August 8, 2018 51 Appendix J1 – Low‐Floor Elevation Assessment Overview of Lowest Floor Issue There seems to be two reasons for establishing a minimum lowest floor elevation in the vicinity of a pond – to prevent flooding of the structure by surface water and to prevent seepage or damage from uplift pressures that could result from a rise in the water table elevation. The first reason (direct flooding) can easily be established with knowledge of the maximum flood elevation of a pond (or the 100‐year elevation, if this is used) and ground surface topography. The second reason (a rise in the water table due to increased pond elevations) is not so straight forward. This second area is the subject of this memo. When a formerly dry pond becomes wet (or when a wet pond’s water elevation increases) due to a storm event, downward seepage of the ponded water begins. The rate of seepage through the bottom of the pond is dependent upon: 1) The elevation of the water surface above the pond bottom 2) The soil type at the bottom of the pond (i.e. the pond bottom’s thickness and permeability) 3) The type of soil underneath the pond (e.g., clay, silt, sand, gravel) 4) The degree of saturation of the soils beneath the pond 5) The depth to the water table In general, higher seepage through the bottom of the pond will occur when the water surface elevation is high, the pond’s bottom sediments are thin and/or sandy, the soils underneath the pond are permeable (such as sand or gravel), the soils underneath the pond have a high moisture content (i.e., they are at field capacity or higher), and the water table is well below the bottom of the pond (i.e. the soils are freely draining). Higher seepage rates through the bottom of the pond will cause the water table elevation to rise by creating a “mounding condition” below the pond. How high and how widespread the water table mound becomes are contributing factors to whether or not basements will be affected. However, the single most important factor that will determine if seepage from a pond will cause wet basement problems is the depth to the water table, below the basement. The magnitude and extent of the groundwater mounding conditions is also contingent upon the aquifer’s transmissivity (aquifer permeability multiplied by aquifer thickness), the specific yield of the aquifer materials, and the duration of the high water levels in the pond. In general, thicker aquifers with higher permeability will experience less mounding than thinner aquifers of lower permeability. Perched aquifers (i.e. groundwater zones less than about 10 feet that overlie extensive clay layers) typically experience the greatest amount of mounding. Riley‐Purgatory‐Bluff Creek Watershed District Rules August 8, 2018 52 Overview of Evaluation Method All of the combinations of settings, pond configurations, aquifer parameters, and distances from ponds cannot be anticipated beforehand in coming up with a method to quickly evaluate whether or not a variance to the minimum floor elevation ordinance should be considered. However, by making some generalities, the most commonly encountered situations can be evaluated. This is the approach taken here. A groundwater flow model of a “typical” pond and aquifer setting was developed. Aquifer parameters and pond elevations were varied and the resulting water table mounding conditions were simulated. The following conditions were evaluated: 1. Pond elevation increases of 2 feet, 4 feet, and 6 feet above normal or dry conditions 2. Depth to the water table (before flooding) of 3 feet (to represent conditions of 3 feet or less) and 10 feet (to represent conditions where the depth to the water table is greater than 3 feet). The purpose of simulating these two conditions is that with shallow water tables, the rate of infiltration is substantially reduced as the groundwater mound rises into the pond. For deeper aquifer conditions, the pond bottom is always above the water table and the depth to the water table has no bearing on the seepage rate. 3. Three aquifer conditions: clay or perched aquifers (transmissivities of 7 ft2/day and specific yield values of 0.1); silt aquifers (transmissivity of 70 ft2/day and specific yield values of 0.2) and sand and gravel aquifers (transmissivities of 2000 ft2/day and specific yield values of 0.2). 4. Pond bottom sediment thickness of 1 feet and bottom sediment hydraulic conductivity of 1 ft/day. 5. Instantaneous occurrence of a flood condition in the pond, which lasts for 25 days, followed by instantaneous reduction to normal conditions. The purpose of using this condition is that the effects of aquifer storage (specific yield) are taken into account. A duration of 25 days was selected as being a reasonable time period of flood conditions. 6. Increases in the water table elevation were recorded at several distances between 5 feet and 200 feet from the pond. The maximum rise during the modeled period was selected for plotting. The U.S. Geological Survey’s groundwater modeling code, MODFLOW, was used for this analysis. How to Determine if a Variance is Warranted In order to determine if a proposed lowest floor elevation is acceptable, the following need to be known: 1. Depth to the water table and an estimation of the water table’s seasonally high elevation. Riley‐Purgatory‐Bluff Creek Watershed District Rules August 8, 2018 53 2. Type of aquifer materials – e.g., clay, silt, sand, gravel 3. Information as to whether or not the water table is perched or is part of a deeper, thicker aquifer system. 4. An estimate of the flood elevation of the pond. 5. The distance of the proposed floor to the pond. Depth to the water table and the type of aquifer material needs to be determined through the installation of soil borings. The other information should be estimated from other sources. Once this information is obtained, the minimum depth to the water table from the bottom of the proposed floor slab can be determined from one of six plots, attached to this memorandum. Which of the six plots to use depends on the depth of the water table with respect to the pond’s bottom and the type of aquifer material (e.g., clay, silt, sand, gravel). The following steps should be used: 1. Determine the closest distance of the proposed floor to the pond (if the pond size increases during flooding, the distance should be from the flooded perimeter of the pond to the proposed floor). 2. Using Plot 1, determine the minimum permissible depth to the water table for the specified distance from the pond. If the actual depth to the water table (see discussion below for determining this) is greater than the value on Plot 1, no further evaluation is necessary – the floor is sufficiently high with respect to the water table that the water table will not reach the bottom of the slab, regardless of the soil type or transmissivity. If the depth to the water table is less than the value from Plot 1, further evaluation is necessary. 3. If the soil type of the aquifer, below the water table, is mostly clay OR if the aquifer is perched (a continuous clay layer is less than 5 feet below the water table), Plot 2 must be used. The appropriate pond level increase (2, 4, or 6 feet) for flood conditions must be used in Plot 2 to find the minimum permissible depth to the water table. If the depth to the water table from Plot 2 is less than the actual depth to the water table, the proposed floor elevation is too low and must be raised to equal the value from Plot 2. 4. If the soil type of the aquifer is mostly silt AND the pond bottom is 3 feet or less above the water table, Plot 3 should be used. 5. If the soil type of the aquifer is mostly sand or gravel AND the pond bottom is 3 feet or less above the water table, Plot 4 should be used. 6. If the soil type of the aquifer is mostly silt AND the pond bottom is 3 feet or more above the water table, Plot 5 should be used. Riley‐Purgatory‐Bluff Creek Watershed District Rules August 8, 2018 54 7. If the soil type of the aquifer is mostly sand or gravel AND the pond bottom is 3 feet or more above the water table, Plot 5 should be used. The values from the plots are guidelines, based on typical conditions. If the plots indicate the proposed floor elevation is too low, additional analyses and data collection could be pursued by the applicant. These additional analyses could include additional soil borings, long‐term monitoring of piezometers, or more sophisticated modeling. Determining Depth to the Water Table If a variance to a lowest floor elevation ordinance is to be considered, the depth to the water table at the location in question must be known. Without this knowledge, there cannot be a technical basis for approving a variance. Furthermore, the applicant should demonstrate that the measured water‐table elevation is both representative of conditions over the entire floor area and is representative of values typical for seasonally high conditions (e.g. spring conditions). A suggested requirement for collecting this information is the following: 1. A minimum of two soil borings must be installed at or near the perimeter of the lowest floor. At least one of these borings must be where the floor is closest to the nearest pond. 2. Soil borings must extend to a depth of at least 7 feet below the water table. The borings must be left open for a time sufficient to determine the stabilized water level in the borehole. The water level must be measured with reference to a known bench mark that can relate the water table elevation to the proposed floor elevation. Soils at or immediately below the water table must be sampled and texturally classified using an approved classification method. Water levels measured during dry summer months or during the winter may be lower than water levels during the spring. The applicant should be required to make an effort to determine the likely amount of seasonal fluctuation in the water table in the area. Water level records from wells completed in the area could be used. If information is unavailable, the applicant should be required to add a value to the measured water table elevation. One suggestion would be to assume 25% of the total annual precipitation (29 inches), divided by the average effective porosity for non‐cohesive soils (0.3), which is: (29 inches/4) x (1 foot/12 inches)/0.3 = 2 feet If the seasonally adjusted maximum water‐table elevation is eight (8) feet or below the bottom of the slab of the lowest floor, it is unlikely that temporary flood conditions in the pond will cause the water table to rise to the level of the floor.6 Determining Soil Type at the Water Table 6 This assumes that the pond level begins to return to normal within about 30 days and the pond level’s increase is not greater than 6 feet. Riley‐Purgatory‐Bluff Creek Watershed District Rules August 8, 2018 55 The textural classification from the soil borings will be necessary for determining the expected rise in the water table caused by an increase in pond elevation. At a minimum, the soil should be classified as one of the following: 1. Sandy or gravely soils – consisting of predominantly sand or gravel, with minor amounts of silt and clay 2. Silty soils – consisting predominantly of silt 3. Clayey soils – consisting predominantly of clay. 56 Riley‐Purgatory‐Bluff Creek Watershed District Rules August 8, 2018 57 Riley‐Purgatory‐Bluff Creek Watershed District Rules August 8, 2018 58 Riley‐Purgatory‐Bluff Creek Watershed District Rules August 8, 2018 59 Riley‐Purgatory‐Bluff Creek Watershed District Rules August 8, 2018 60 Riley‐Purgatory‐Bluff Creek Watershed District Rules August 8, 2018 61 Geotechnical Evaluation Report Pleasant View Pointe Development 6535 Peaceful Lane Chanhassen, Minnesota Prepared for Rachel Development , Inc. Professional Certification: I hereby certify that this plan, specification, or report was prepared by me or under my direct supervision and that I am a duly Licensed Professional Engineer under the laws of the State of Minnesota. John T. Carlson, PE Senior Engineer License Number: 20663 February 17, 2025 Project B2405314 Braun Intertec Corporation AA/EOE Braun Intertec Corporation 11001 Hampshire Avenue S Minneapolis, MN 55438 Phone: 952.995.2000 Fax: 952.995.2020 Web: braunintertec.com February 17, 2025 Project B2405314 Mr. Paul Robinson Rachel Development, Inc. 4180 Napier Court NE St. Michael, MN 55446 Re: Geotechnical Evaluation Pleasant View Pointe Development 6535 Peaceful Lane Chanhassen, Minnesota Dear Mr. Robinson: We are pleased to present this Geotechnical Evaluation Report for the proposed Pleasant View Pointe residential development in Chanhassen, Minnesota. Please read the entire attached report for details regarding our findings and recommendations. Thank you for making Braun Intertec Corporation your geotechnical consultant for this project. If you have questions about this report, or if there are other services that we can provide in support of our work to date, please contact John Carlson at 952.540.7248 (johcarlson@braunintertec.com). Sincerely, BRAUN INTERTEC CORPORATION Henry Vloo, PE Senior Engineer John T. Carlson, PE Senior Engineer Cc: Steve Wolbeck; Rachel Development, LLC Mark Rausch, PE; Alliant Engineering, Inc. Joe Westphal, PE; Braun Intertec Corporation Table of Contents Description Page A. Introduction ...................................................................................................................................... 1 A.1. Project Description .............................................................................................................. 1 A.1.a. Structural Loads ...................................................................................................... 2 A.1.b. Pavement Traffic Loads .......................................................................................... 2 A.2. Site Conditions and History ................................................................................................. 2 A.3. Purpose ................................................................................................................................ 3 A.4. Background Information and Reference Documents .......................................................... 3 A.5. Scope of Services ................................................................................................................. 4 B. Results .............................................................................................................................................. 5 B.1. Geologic Overview .............................................................................................................. 5 B.2. Boring Results ...................................................................................................................... 5 B.3. Groundwater ....................................................................................................................... 6 B.4. Laboratory Test Results ....................................................................................................... 6 C. Recommendations ........................................................................................................................... 6 C.1. Design and Construction Discussion ................................................................................... 6 C.1.a. Building Subgrade Preparation .............................................................................. 6 C.1.b. Reuse of On-Site Soils ............................................................................................. 7 C.1.c. Disturbance of On-Site Soils ................................................................................... 7 C.1.d. Effects of Groundwater .......................................................................................... 7 C.2. Site Grading and Subgrade Preparation .............................................................................. 7 C.2.a. Building Subgrade Excavations ............................................................................... 7 C.2.b. Excavation Oversizing ............................................................................................. 9 C.2.c. Excavated Slopes .................................................................................................... 9 C.2.d. Filling on Slopes .................................................................................................... 10 C.2.e. Excavation Dewatering ......................................................................................... 10 C.2.f. Selecting Excavation Backfill and Additional Required Fill ................................... 10 C.2.g. Pavement and Exterior Slab Subgrade Preparation ............................................. 10 C.2.h. Pavement Subgrade Proofroll .............................................................................. 11 C.2.i. Engineered Fill Materials and Compaction Requirements ................................... 11 C.3. Spread Footings ................................................................................................................. 13 C.3.a. Embedment Depth ............................................................................................... 13 C.3.b. Subgrade Improvement ....................................................................................... 13 C.3.c. Net Allowable Bearing Pressure ........................................................................... 14 C.3.d. Settlement ............................................................................................................ 14 C.4. Basement Walls ................................................................................................................. 14 C.4.a. Drainage Control .................................................................................................. 14 C.4.b. Selection, Placement and Compaction of Backfill ................................................ 16 C.4.c. Configuring and Resisting Lateral Loads............................................................... 17 C.5. Interior Slabs ..................................................................................................................... 17 C.5.a. Moisture Vapor Protection .................................................................................. 17 C.5.b. Radon ................................................................................................................... 18 C.6. Frost Protection ................................................................................................................. 18 C.6.a. General ................................................................................................................. 18 C.6.b. Frost Heave Mitigation ......................................................................................... 18 C.7. Pavements ......................................................................................................................... 20 Table of Contents (continued) Description Page C.7.a. Design Sections .................................................................................................... 20 C.7.b. Bituminous Pavement Materials .......................................................................... 20 C.7.c. Subgrade Drainage ............................................................................................... 20 C.7.d. Performance and Maintenance ........................................................................... 20 C.8. Utilities .............................................................................................................................. 21 C.8.a. Subgrade Stabilization .......................................................................................... 21 C.8.b. Selection, Placement, and Compaction of Backfill ............................................... 21 C.8.c. Corrosion Potential .............................................................................................. 21 C.9. Stormwater........................................................................................................................ 21 D. Procedures...................................................................................................................................... 22 D.1. Penetration Test Borings ................................................................................................... 22 D.2. Exploration Logs ................................................................................................................ 22 D.2.a. Log of Boring Sheets ............................................................................................. 22 D.2.b. Log of Test Pit Sheets ........................................................................................... 22 D.2.c. Geologic Origins ................................................................................................... 22 D.3. Material Classification and Testing ................................................................................... 23 D.3.a. Visual and Manual Classification .......................................................................... 23 D.3.b. Laboratory Testing ............................................................................................... 23 D.4. Groundwater Measurements ............................................................................................ 23 E. Qualifications .................................................................................................................................. 23 E.1. Variations in Subsurface Conditions .................................................................................. 23 E.1.a. Material Strata ..................................................................................................... 23 E.1.b. Groundwater Levels ............................................................................................. 24 E.2. Continuity of Professional Responsibility .......................................................................... 24 E.2.a. Plan Review .......................................................................................................... 24 E.2.b. Construction Observations and Testing ............................................................... 24 E.3. Use of Report..................................................................................................................... 24 E.4. Standard of Care ................................................................................................................ 24 Appendix Soil Boring Location Sketch Log of Boring Sheets ST-1 through ST-8 Log of Test Pit Sheets TP-1 through TP-8 Descriptive Terminology of Soil A. Introduction A.1. Project Description Rachel Development, Inc. (Rachel) is planning to develop a new residential housing development on the four parcels of land known as the Beddor Properties. One of the properties has an address of 6535 Peaceful Lane in Chanhassen, Minnesota. Concept plans indicate that the proposed development will likely consist of construction of 19 single-family building pads along with construction of associated streets, underground utilities, and stormwater features/ponds. Figure 1 shows the proposed site development plan dated May 1, 2024 prepared by Alliant Engineering. Figure 1. Beddor Property – Initial Concept Plan Concept site plan prepared by Alliant Engineering. Rachel Development, Inc. Project B2405314 February 17, 2025 Page 2 A.1.a. Structural Loads Construction will likely consist of one- to two-story wood-framed houses with pitched roofs. The homes will likely be constructed with full-depth basements with wood framing above grade. A.1.b. Pavement Traffic Loads We have assumed that bituminous pavements, typical of residential neighborhoods, will be subjected to normal traffic conditions over a design life of 20 years. A.2. Site Conditions and History The site consists of four parcels of land totaling about 13 1/4 acres of mostly open property. There is a home on one of the properties. There are scattered wooded areas on this site as well as a pond in the north parcel. Just off the southwest corner of the site is a City of Chanhassen water storage facility. The site generally slopes down to the northwest, with the highest elevations of about 1025 Mean Sea Level (MSL) near the water storage facility in the southwest part of the site down to the low area of the site at about 925 MSL near the existing pond in the northwest part of the site. Figure 2 shows an aerial photograph showing the current site conditions, as obtained from the Carver County GIS site using 2022 aerial imagery. Rachel Development, Inc. Project B2405314 February 17, 2025 Page 3 Figure 2. Aerial Photograph of the Site - 2022 Photograph obtained from Carver County GIS. A.3. Purpose The purpose of our geotechnical evaluation will be to characterize subsurface geologic conditions at selected exploration locations and evaluate their impact on the design and construction of the proposed residential development. A.4. Background Information and Reference Documents We reviewed the following information: ▪ Site information provided to us by Rachel. ▪ Concept plan dated May 1, 2024 prepared by Alliant Engineering. ▪ Available public aerial photographs showing the existing site conditions. ▪ Geologic atlas showing the general soil types present in this area. Rachel Development, Inc. Project B2405314 February 17, 2025 Page 4 We have described our understanding of the proposed construction and site to the extent others reported it to us. Depending on the extent of available information, we may have made assumptions based on our experience with similar projects. If we have not correctly recorded or interpreted the project details, the project team should notify us. New or changed information could require additional evaluation, analyses and/or recommendations. A.5. Scope of Services We completed our services based on the Proposal for Geotechnical Evaluation QTB197503 to Rachel Development, Inc. dated May 29, 2024. The following list describes the geotechnical tasks completed in accordance with our authorized scope of services. ▪ Reviewing the background information and reference documents previously cited. ▪ Coordinating the clearing of the exploration locations of public underground utilities. The soil boring locations were chosen and staked in the field by Braun Intertec. The existing ground surface elevations at the borings were obtained by Braun Intertec personnel using a GPS locating system. ▪ Performing eight standard penetration test (SPT) borings, denoted as ST-1 to ST-8, to nominal depths of 15 to 20 feet below grade across the site. ▪ Performing laboratory testing on select samples to aid in soil classification and engineering analysis. ▪ After the borings were completed, we were requested to observe backhoe test pits to further evaluate the soil conditions. A total of eight test pits were observed by Braun Intertec on January 8, 2025. Alliant Engineering provided the surface elevations at the test pit locations. ▪ Preparing this report containing a boring location sketch, logs of the soil borings, a summary of the soils encountered by the borings, results of laboratory tests, and recommendations for structure and pavement subgrade preparation and the design of foundations, floor slabs, exterior slabs, and utilities. We are currently completing a Phase 1 ESA (Environmental Site Assessment) for this site. The Phase I ESA report was sent under separate cover. Our current scope of services did not include any other environmental services. Rachel Development, Inc. Project B2405314 February 17, 2025 Page 5 B. Results B.1. Geologic Overview We reviewed the map “Surficial Geology of the Twin Cities Metropolitan Area, Minnesota,” dated 2007. Based upon the map, the site is underlain by glacial till deposits associated with the New Ulm Formation. Glacial till associated with the Des Moines lobe typically consists of clayey soils with small but variable amounts of gravel, and lesser amounts of cobbles. The depth of soil to the bedrock surface is generally greater than 250 feet beyond the current ground surface. We based the geologic origins used in this report on the soil types, in-situ and laboratory testing, and available common knowledge of the geological history of the site. Because of the complex depositional history, geologic origins can be difficult to ascertain. B.2. Boring Results Table 1 provides a summary of the soil boring results in the general order we encountered the strata. Please refer to the Log of Boring sheets in the Appendix for additional details. The Descriptive Terminology sheet in the Appendix includes definitions of abbreviations used in Table 1. Table 1. Subsurface Profile Summary* Strata Soil Type - ASTM Classification Range of Penetration Resistances Commentary and Details Topsoil, Topsoil fill CL, SC, SM NA ▪ Encountered by all the borings and test pits. Consisted of lean clay, clayey sand, and silty sand. ▪ Thickness ranged from about 1/2 to 4 feet. ▪ Dark brown in color. ▪ Moisture condition generally moist or frozen. Swamp deposits OL, OH 3 to 5 Blows per Foot (BPF) ▪ Only encountered by Borings ST-3 and ST-4 and Test Pit TP-2 to depths of about 4 and 6 feet. ▪ Consisted of organic clay or organic silt with fibers. ▪ Black in color. ▪ Moisture condition generally moist. Alluvial deposits CL, SC 0 to 5 BPF ▪ Encountered by Borings ST-1, ST-3, and ST-4 and Test Pits TP-2. ▪ Consisted of clayey sand and lean clay. ▪ Extended to depths of about 4 to 13 feet. ▪ Color mostly brown, brownish gray and gray. ▪ Moisture condition generally moist to wet. Rachel Development, Inc. Project B2405314 February 17, 2025 Page 6 Strata Soil Type - ASTM Classification Range of Penetration Resistances Commentary and Details Glacial deposits SC, CL 4 to 28 BPF ▪ Encountered by all the borings and test pits. ▪ Consisted of clayey sand and sandy lean clay. ▪ Color mostly brown and grayish brown, transitioning to gray at depth. ▪ Moisture condition generally moist to wet. *Abbreviations defined in the attached Descriptive Terminology sheet. B.3. Groundwater While completing the soil borings, water was only observed in Boring ST-5 at a depth of about 10 1/2 feet, or an elevation of about 999 MSL. Based on the results of the soil borings, it is our opinion that the water observed in Boring ST-5 is perched within more granular soil underlain by more impervious soil. It is likely that there is a local water level near the existing pond in the northwest part of the site. Seasonal and annual fluctuations of groundwater should be anticipated. B.4. Laboratory Test Results The boring logs show the results of the laboratory testing we performed on the soil borings, next to the tested sample depth. The laboratory tests were all completed in general conformance with the applicable American Society for Testing and Materials (ASTM) standards. The Log of Boring sheets are in the Appendix of this report. The moisture content tests (ASTM D 2216) performed on selected clayey soil samples showed moisture contents ranging from about 17 to 27 percent. Most of the clayey soils tested appeared to be near or slightly above the soils’ estimated optimum moisture content, although some of the alluvial clay soils were much above their optimum moisture contents. C. Recommendations C.1. Design and Construction Discussion C.1.a. Building Subgrade Preparation Based on the results of our subsurface exploration and evaluation, spread footing foundations bearing on engineered fill and/or native soils can support the proposed houses after performing typical subgrade Rachel Development, Inc. Project B2405314 February 17, 2025 Page 7 preparation. Typical subgrade preparation includes removing existing vegetation, topsoil, or organic soils, fill, and areas of soft clay. Any existing structures, including slabs and foundations, as well as pavements and septic systems will also need to be removed. Any wells on the property will need to be properly sealed. We estimate that cuts and fills could range from about 5 to 10 feet below, or above, existing grades. Any soil correction work to further remove unsuitably soft soils could add or subtract to the assumed cut and fill depths. Based on the soil borings, soil correction work could range from around 1 to 11 feet. C.1.b. Reuse of On-Site Soils Most of the on-site soils, free of organic materials appear suitable for reuse as engineered fill. Some of the lean clay, sandy lean clay, and clayey sand will likely require some moisture conditioning to allow the recommended soil compaction levels to be achieved. This includes both drying and wetting the soils. If fill soil is mined from beneath wooded areas, the clayey soils could be dry of optimum and will need to be properly wetted if these soils are used as structural fill. The higher moisture content lean clay should not be used as structural fill below the proposed houses or streets, unless they can be properly moisture conditioned. C.1.c. Disturbance of On-Site Soils We caution that the clayey nature of some of the site soils makes them very susceptible to disturbance from construction. Care should be taken not to disturb these soils during construction, as once stable subgrades are destabilized, they will require additional moisture conditioning and compacting. C.1.d. Effects of Groundwater Groundwater is anticipated to be below typical excavation depths at this site, although perched water could be present at higher elevations within layers of granular soils overlying lower permeability soils. The contractor should immediately remove any collected water within the excavations to facilitate construction and proper backfilling. C.2. Site Grading and Subgrade Preparation C.2.a. Building Subgrade Excavations We recommend removing unsuitable materials from beneath house pads and oversize areas. We define unsuitable materials as vegetation, topsoil, organic soils, fill, existing structures, existing utilities, and soft/loose soil. Rachel Development, Inc. Project B2405314 February 17, 2025 Page 8 Table 2 shows the anticipated excavation depths and bottom of soil correction excavation elevations at each of the current soil boring and test pit locations, assuming that structures, utilities, or roads will be built at each location. Excavation depths could be reduced in areas that will not support future structures, utilities, or roads. Table 2. Recommended Excavation Depths for Building Pads and Streets Location Measured Surface Elevation (feet) Anticipated Excavation Depth (feet) Anticipated Bottom Elevation (feet) ST-1 1008.3 4 1004 ST-2 1005.8 1 1004 1/2 ST-3 995.4 Pond area --- ST-4 996.2 Pond area --- ST-5 1009.4 7 1002 1/2 ST-6 1021.2 1/2 1020 1/2 ST-7 1025.6 1 1024 1/2 ST-8 1023.3 1 1/2 1022 TP-1 1003.1 Pond area --- TP-2 996.1 Pond area --- TP-3 1005.5 Pond area --- TP-4 1018.4 1 1/2 1017 TP-5 1001.1 2 999 TP-6 1009.9 3 1007 TP-7 1019.4 4 1015 1/2 TP-8 1040.6 1/2 1040 Excavation depths will vary between the borings and test pits. Portions of the excavations may also extend deeper than indicated by the borings and test pits. A geotechnical representative should observe the excavations to make the necessary field judgments regarding the suitability of the exposed soils. Any disturbed areas should be moisture conditioned, if necessary, and re-compacted. The contractor should use equipment and techniques to reduce soil disturbance. If soils become disturbed or are wet, we recommend excavation and replacement of the disturbed or unstable soils. Provided the existing soils do not become disturbed, surface compaction will not be necessary prior to construction of footings. Rachel Development, Inc. Project B2405314 February 17, 2025 Page 9 C.2.b. Excavation Oversizing When removing unsuitable materials below structures or pavements, we recommend the excavation extend outward and downward at a slope of 1H:1V (horizontal:vertical) or flatter. See Figure 3 for an illustration of excavation oversizing. Figure 3. Generalized Illustration of Oversizing C.2.c. Excavated Slopes Based on the borings, we anticipate the near surface on-site soils in excavations will consist of mostly clayey soils. The clayey soils are typically considered Type B Soil under OSHA (Occupational Safety and Health Administration) guidelines. OSHA guidelines indicate unsupported excavations in Type B soils should have a gradient no steeper than 1:H:1V. Slopes constructed in this manner may still exhibit surface sloughing. OSHA requires an engineer to evaluate slopes or excavations over 20 feet in depth. An OSHA-approved qualified person should review the soil classification in the field. Excavations must comply with the requirements of OSHA 29 CFR, Part 1926, Subpart P, “Excavations and Trenches.” This 1. Engineered fill as defined in C.2.i 2. Excavation oversizing minimum of 1 to 1 (horizontal to vertical) slope or flatter 3. Engineered fill as required to meet pavement support or landscaping requirements as defined in C.2.i 4. Excavation back-slope to OSHA requirements Rachel Development, Inc. Project B2405314 February 17, 2025 Page 10 document states excavation safety is the responsibility of the contractor. The project specifications should reference these OSHA requirements. C.2.d. Filling on Slopes Where existing or excavated grades are steeper than 4H:1V, we recommend placing fill from low to high elevations on horizontal benches cut into the native soils so that successive lifts are spread and compacted on level surfaces, and a potential failure surface is not created along the fill’s lower boundary. Depending on fill requirements, the contractor can construct benches by cutting into existing grades while placing fill (the composition of the exposed soils thus being in compliance with fill specifications), or by cutting the benches in advance of filling (to prevent mixing with soils not in compliance with fill specifications). The height of a given bench may vary but the width should consistently be great enough to accommodate large, self-propelled compaction equipment. C.2.e. Excavation Dewatering Although likely perched water was observed in Boring ST-5, perched water could also be encountered in other parts of the site. We recommend removing any water from the excavations. Project planning should include temporary sumps and pumps for excavations in low-permeability soils, such as clays and silts. C.2.f. Selecting Excavation Backfill and Additional Required Fill On-site soils free of organic soil and debris can be considered for reuse as backfill and fill. However, the topsoil and the organic soils should not be re-used as engineered fill under the building pads or below streets. In addition, any higher moisture content lean clay soils should also not be used as engineered fill below building pads and streets unless they can be properly moisture conditioned. Some of the clayey soils on this site are both wet and dry of optimum. Therefore, drying of these soils, or wetting, will be critical to the success of the site. The wet soils should be continuously disced to lower the moisture content to near optimum. For dry clayey soils, water should be added to the soils and then thoroughly mixed with the soil to obtain a uniform moisture content in these soils. The moisture condition (drying or wetting) of the soils would be best done in the warmer less rainy months of July and August, where the soils can be properly dried, if needed. The drier months will also allow the contractor to better control the moisture content of the soil, should water need to be added to them. C.2.g. Pavement and Exterior Slab Subgrade Preparation We recommend the following steps for pavement and exterior slab subgrade preparation. Note that project planning may need to require additional subcuts to limit frost heave. Rachel Development, Inc. Project B2405314 February 17, 2025 Page 11 1. Strip unsuitable soils consisting of topsoil, organic soils, vegetation, and soft clay or existing structures and pavements from the area, down to suitable native soils below the proposed pavement surface. 2. Have a geotechnical representative observe the excavated subgrade to evaluate if additional subgrade improvements are necessary. 3. Slope subgrade soils to areas of sand or drain tile to allow the removal of accumulating water. 4. Scarify, moisture condition and surface compact the subgrade with at least 3 passes by a large roller with a minimum drum diameter of 3 1/2 feet. 5. Place pavement subgrade fill to grade and compact in accordance with Section C.2.i to bottom of pavement and exterior slab section. 6. Proofroll the pavement or exterior slab subgrade as described in Section C.2.h. C.2.h. Pavement Subgrade Proofroll After preparing the subgrade as described above and prior to the placement of the aggregate base, we recommend proofrolling the subgrade soils with a fully loaded tandem-axle truck. We also recommend having a geotechnical representative observe the proofroll. Areas that fail the proofroll likely indicate soft or weak areas that will require additional soil correction work to support pavements or slabs. The contractor should correct areas that display excessive yielding or rutting during the proofroll, as determined by the geotechnical representative. Possible options for subgrade correction include moisture conditioning and re-compaction, subcutting and replacement with soil or crushed aggregate, chemical stabilization and/or geotextiles. We recommend performing a second proofroll after the aggregate base material is in place, and prior to placing bituminous or concrete pavement/slabs. C.2.i. Engineered Fill Materials and Compaction Requirements Table 3 below contains our recommendations for engineered fill materials. Table 3. Engineered Fill Materials Locations To Be Used Engineered Fill Classification Possible Soil Type Descriptions Gradation Additional Requirements ▪ Below foundations ▪ Below interior slabs Structural fill* CL, SC 100% passing 2-inch sieve < 2% Organic Content (OC) Plasticity Index (PI) < 20% Rachel Development, Inc. Project B2405314 February 17, 2025 Page 12 Locations To Be Used Engineered Fill Classification Possible Soil Type Descriptions Gradation Additional Requirements ▪ Drainage layer ▪ Non-frost- susceptible ▪ Free-draining ▪ Non-frost- susceptible fill GP, GW, SP, SW 100% passing 1-inch sieve < 50% passing #40 sieve < 5% passing #200 sieve < 2% OC Behind below-grade walls, beyond drainage layer Retained fill SP, SP-SM, SM, SC, CL 100% passing 3-inch sieve < 20% passing #200 sieve < 2% OC PI < 4% Pavements Pavement fill CL, SC 100% passing 3-inch sieve < 2% OC PI < 20% Below landscaped surfaces, where subsidence is not a concern Non-structural fill All soil types 100% passing 6-inch sieve < 10% OC *More select soils comprised of coarse sands with < 5% passing #200 sieve may be needed to accommodate work occurring in periods of wet or freezing weather. If there are building pads that will require more than 10 feet of compacted fill under the lowest floor slabs, a construction delay may be needed if only clay fill is used to fill these building pads. The construction delay could range from 3 to 12 months, depending on the final depths of clay fill used. As an alternative, on lots where deep fills are needed, clean sand fill (less than 12 percent passing the #200 sieve) could be used to initially fill the excavations below these house pads. The clean sand fill should be placed in thin compacted lifts, up to an elevation of 10 feet or less from finished basement floor grades. (Based on the borings, this sand would need to be imported to the site.) On-site clay can then be used to complete construction of the building pads. If the alternative method of filling the house pads is used, a construction delay would not be needed. For large self-propelled vibratory compactors, we recommend spreading engineered fill in loose lifts of no more than 12 inches thick. For walk-behind compactors, we recommend spreading engineered fill in loose lifts of no more than 6 inches thick. We recommend compacting fill in accordance with the criteria presented below in Table 4. The project documents should specify relative compaction of fill, based on the structure located above the fill, and vertical proximity to that structure. Rachel Development, Inc. Project B2405314 February 17, 2025 Page 13 Table 4. Compaction Recommendations Summary Reference Relative Compaction, percent (ASTM D698 – Standard Proctor) Moisture Content Variance from Optimum, percentage points < 12% Passing #200 Sieve (SP, SP-SM) > 12% Passing #200 Sieve (CL, SC, SM) Below building pads and oversizing zones, less than 10 feet of fill. 95 *--- -1 to +3 Below building pads and oversizing zones, more than 10 feet of fill. 98 *--- -1 to +3 Within 3 feet of pavement subgrade 100 *--- -2 to +1 More than 3 feet below pavement subgrade 95 *--- -1 to +3 Below landscaped surfaces 90 *--- -1 to +5 Adjacent to below-grade wall (exterior wall backfill) 95** *--- -1 to +3 *The minimum moisture content should be no less than 5 percent and no more than 3 percentage points over optimum. **Increase compaction requirement to meet compaction required for structure supported by this engineered fill. The project documents should not allow the contractor to use frozen material as fill or to place fill on frozen material. Frost should not penetrate under foundations during construction. We recommend performing density tests in fill to evaluate if the contractors are effectively compacting the soil and meeting project requirements. Refer to Section C.3.d below for additional remarks for thicker layers of fill soils. C.3. Spread Footings C.3.a. Embedment Depth For frost protection, we recommend embedding perimeter footings of the proposed houses, including attached garages, a minimum of 42 inches below the lowest exterior grade. Interior footings may be placed directly below floor slabs unless they will be subjected to freezing. We recommend embedding building footings not heated during winter construction, and other unheated footings associated with decks, porches, or stoops, 60 inches below the lowest exterior grade. C.3.b. Subgrade Improvement If a small amount of groundwater is present within the footing excavation, or if the footing subgrade soils become disturbed prior to placing forms or reinforcement, we recommend subcutting any soft or wet Rachel Development, Inc. Project B2405314 February 17, 2025 Page 14 soil and placing a 6- to 12-inch layer of clear rock. The clear rock will provide a stable working surface and will allow for the flow of water to a drain tile or sump pump. C.3.c. Net Allowable Bearing Pressure We recommend sizing spread footings to exert a net allowable bearing pressure of up to 2,000 pounds per square foot (psf). This value includes a safety factor of at least 3.0 with regard to bearing capacity failure. C.3.d. Settlement We estimate that total and differential settlements among the footings will amount to less than 1 and 1/2 inch, respectively, under the assumed loads. If there are areas where more than 10 feet of fill is required, higher settlements could occur, unless the deeper fill areas are only filled with poorly graded sand (SP) or poorly graded sand with silt (SP-SM) fill. If deep fill areas are completed using clay soil, a construction delay may also be needed to allow the fill soils to consolidate under its own weight. Construction delays could range from 3 to 12 months, depending on the type of fill used, the compaction level obtained in the fill and the thickness of the fill. The construction delays should be evaluated after grading is completed by using settlement plates to monitor the consolidation of the fill. C.4. Basement Walls The following sections address soil parameters for basement wall design. Although construction of retaining walls has not been specified for this project to date, the following recommendations can also be used for preliminary retaining wall design. Additional soil analysis, including additional soil borings, may be needed for final retaining wall design. C.4.a. Drainage Control We recommend installing drain tile to remove water behind the below-grade walls at the location shown in Figure 4. The below-grade wall drainage system should also incorporate free-draining, engineered fill or a drainage board placed against the wall and connected to the drain tile. Even with the use of free-draining, engineered fill, we recommend general waterproofing of below-grade walls that surround occupied or potentially occupied areas because of the potential cost impacts related to seepage after construction is complete. Rachel Development, Inc. Project B2405314 February 17, 2025 Page 15 Figure 4. Generalized Illustration of Wall Engineered Fill The materials listed in the sketch should meet the definitions in Section C.4.b. The low-permeability material should be capable of directing water away from the wall, like clay, topsoil, or pavement. The project documents should indicate if the contractor should brace the walls prior to filling, and the allowable unbalanced fill heights. As shown in Figure 4, we recommend Zone 2 consist of retained, engineered fill, and this material will control lateral pressures on the wall. However, we are also providing design parameters for using other engineered fill material. If final design uses non-sand material for engineered fill, project planning should account for the following items: ▪ Other engineered fill material may result in higher lateral pressure on the wall. ▪ Other engineered fill material may be more difficult to compact. 1. 2-foot wide area of Free- Draining Engineered Fill or Drainage Board 2. Retained Engineered Fill 3. 1 foot of Low-Permeability Soil or Pavement Rachel Development, Inc. Project B2405314 February 17, 2025 Page 16 ▪ Post-construction consolidation of other engineered fill material may result in settlement- related damage to the structures or slabs supported on the engineered fill. Post-construction settlement of other engineered fill material may also cause drainage towards the structure. The magnitude of consolidation could be up to about 3 percent of the wall fill thickness. C.4.b. Selection, Placement and Compaction of Backfill Unless a drainage composite is placed against the backs of the exterior perimeter basement walls, we recommend that backfill placed within 2 horizontal feet of those walls consist of sand having less than 50 percent of the particles, by weight, passing a #40 sieve and less than 5 percent of the particles, by weight, passing a #200 sieve. If clay or silt must be considered for use to make up the balance of the below-grade wall backfill (assuming a drainage composite or sand is placed against the backs of the walls), post-compaction consolidation of the clay and silt occurring under its own weight can be expected to continue beyond the end of construction. The magnitude of consolidation could amount to between 1 and 3 percent of the backfill thickness, or wall height, and if not accommodated, could cause slabs or pavements to settle unfavorably or be damaged. Should clay or silt still be considered for use as backfill, however, we further recommend that: ▪ The bottoms of the excavations required for basement wall construction are wide enough to accommodate compaction equipment. ▪ Backfill is placed at moisture contents at least equal to, but not more than, 3 percentage points above its optimum moisture content. ▪ Backfill is placed in loose lifts no thicker than 6 inches prior to compaction. ▪ The relative compaction of the backfill is measured through density testing at intervals not exceeding 1 test per 50 horizontal feet for each 2 vertical feet of backfill placed. We recommend using a walk-behind compactor to compact the backfill placed within about 5 feet of the basement walls. Further away than that, a self-propelled compactor can be used. Compaction criteria for basement walls should be determined based on the compaction recommendations provided above in Section C.2. Exterior wall backfill not capped with slabs or pavement should be capped with a low-permeability soil to limit the infiltration of surface drainage into the backfill. The finished surface should also be sloped to divert water away from the walls. Rachel Development, Inc. Project B2405314 February 17, 2025 Page 17 C.4.c. Configuring and Resisting Lateral Loads Below-grade wall design can use active earth pressure conditions if the walls can rotate slightly. If the wall design cannot tolerate rotation, then design should use at-rest earth pressure conditions. Rotation up to 0.002 times the wall height is generally required for walls supporting sand. Rotation up to 0.02 times the wall height is required when wall supports clay. Table 5 presents our recommended lateral coefficients and equivalent fluid pressures for wall design of active, at-rest and passive earth pressure conditions. The table also provides recommended wet unit weights and internal friction angles. Designs should also consider the slope of any engineered fill and dead or live loads placed behind the walls within a horizontal distance that is equal to the height of the walls. Our recommended values assume the wall design provides drainage so water cannot accumulate behind the walls. The construction documents should clearly identify what soils the contractor should use for engineered fill of walls. Table 5. Recommended Below-Grade Wall Design Parameters – Drained Conditions Retained Soil Wet Unit Weight (pcf) Friction Angle (degrees) Equivalent Active Fluid Pressure* (pcf) Equivalent At-Rest Fluid Pressure* (pcf) Equivalent Passive Fluid Pressure* (pcf) Imported Sand (SP, SP-SM) 120 33 35 55 NA Clay Soil (CL, SC) 125 26 50 70 320 *Based on Rankine model for soils in a region behind the wall extending at least 2 horizontal feet beyond the bottom outer edges of the wall footings and then rising up and away from the wall at an angle no steeper than 60 degrees from horizontal. Sliding resistance between the bottom of the footing and the soil can also resist lateral pressures. We recommend assuming a sliding coefficient equal to 0.30 between the concrete and clay soil. The values presented in this section are un-factored. C.5. Interior Slabs C.5.a. Moisture Vapor Protection Excess transmission of water vapor could cause floor dampness, certain types of floor bonding agents to separate, or mold to form under floor coverings. If project planning includes using floor coverings or coatings, we recommend placing a vapor retarder or vapor barrier immediately beneath the slab. We also recommend consulting with floor covering manufacturers regarding the appropriate type, use and installation of the vapor retarder or barrier to preserve warranty assurances. Rachel Development, Inc. Project B2405314 February 17, 2025 Page 18 C.5.b. Radon We recommend installing radon resistant construction components for the proposed building, including appropriate sub-slab material and vent piping, if required by applicable local building codes. Our radon mitigation professionals can assist with evaluation of site-specific radon resistant construction requirements and/or design of a system, at your request. C.6. Frost Protection C.6.a. General Clayey soils will likely underlie most of the exterior slabs, as well as pavements. Most of the clayey soils are moderately to highly frost susceptible. The fine-grained soils can retain moisture and heave upon freezing. In general, this characteristic is not an issue unless these soils become saturated, due to surface runoff or infiltration, or are excessively wet in situ. Once frozen, unfavorable amounts of general and isolated heaving of the soils and the surface structures supported on them could develop. This type of heaving could affect design drainage patterns and the performance of exterior slabs and pavements, as well as any isolated exterior footings and piers. Note that general runoff and infiltration from precipitation are not the only sources of water that can saturate subgrade soils and contribute to frost heave. Roof drainage and irrigation of landscaped areas, close to exterior slabs, pavements, and isolated footings and piers, contribute as well. C.6.b. Frost Heave Mitigation To address some of the heave related issues, we recommend setting general site grades and grades for exterior surface features to direct surface drainage away from buildings, across large, paved areas and away from walkways. Such grading will limit the potential for saturation of the subgrade and subsequent heaving. General grades should also have enough “slope” to tolerate potential larger areas of heave, which may not fully settle after thawing. Even small amounts of frost-related differential movement at walkway joints or cracks can create tripping hazards. Project planning can explore several subgrade-improvement options to address this condition. One of the more conservative subgrade improvement options to mitigate potential heave is removing any frost-susceptible soils present below the exterior slab areas down to a minimum depth of 4 feet below subgrade elevations. We recommend filling the resulting excavation with non-frost-susceptible fill. We also recommend sloping the bottom of the excavation toward one or more collection points to remove any water entering the engineered fill. This approach will not be effective in controlling frost heave without removing the water. Rachel Development, Inc. Project B2405314 February 17, 2025 Page 19 An important geometric aspect of the excavation and replacement approach described above is sloping the banks of the excavations to create a more gradual transition between the unexcavated soils considered frost susceptible and the engineered fill in the excavated area, which is not frost susceptible. The slope allows attenuation of differential movement that may occur along the excavation boundary. We recommend slopes that are 3H:1V, or flatter, along transitions between frost-susceptible and non- frost-susceptible soils. Figure 5 that follows shows an illustration summarizing some of the recommendations. Figure 5. Frost Protection Geometry Illustration Another option is to limit frost heave in critical areas, such as doorways and entrances, via frost-depth footings or localized excavations with sloped transitions between frost-susceptible and non-frost- susceptible soils, as described above. Over the life of slabs and pavements, cracks will develop, and joints will open which will expose the subgrade and allow water to enter from the surface and either saturate or perch atop the subgrade soils. This water intrusion increases the potential for frost heave or moisture-related distress near the crack or joint. Therefore, we recommend implementing a detailed maintenance program to seal and/or fill any cracks and joints. The maintenance program should give special attention to areas where dissimilar materials abut one another, where construction joints occur and where shrinkage cracks develop. Rachel Development, Inc. Project B2405314 February 17, 2025 Page 20 C.7. Pavements C.7.a. Design Sections Our scope of services for this project did not include laboratory tests on subgrade soils to determine an R-value for pavement design. Since much of the soils on this site consist of clay, we recommend that the pavements be designed for an assume R-value of 12. Note the contractor may need to perform limited removal of unsuitable or less suitable soils to achieve this value. We assumed that pavements for the residential development will be subject to a maximum of 50,000 ESALs over a 20-year design life. We assume the pavements will be designed in accordance with the City of Chanhassen standard pavement section which includes a sand subbase. C.7.b. Bituminous Pavement Materials Appropriate mix designs are critical to the performance of flexible pavements. We can provide recommendations for pavement material selection during final pavement design. C.7.c. Subgrade Drainage We recommend installing perforated drainpipes throughout pavement areas at low points, around catch basins, and behind curb in landscaped areas. We also recommend installing drainpipes along pavement and exterior slab edges where exterior grades promote drainage toward those edge areas. The contractor should place drainpipes at the base of the granular subbase layer, or in shallow trenches, extending just below the aggregate base material where no subbase is present. C.7.d. Performance and Maintenance We based the above pavement designs on a 20-year performance life for bituminous. This is the amount of time before we anticipate the pavement will require reconstruction. This performance life assumes routine maintenance, such as seal coating and crack sealing. The actual pavement life will vary depending on variations in weather, traffic conditions and maintenance. It is common to place the non-wear course of bituminous and then delay placement of the wear course. For this situation, we recommend evaluating if the reduced pavement section will have sufficient structure to support construction traffic. Many conditions affect the overall performance of the exterior slabs and pavements. Some of these conditions include the environment, loading conditions and the level of ongoing maintenance. With bituminous pavements, it is common to have thermal cracking develop within the first few years of placement and continue throughout the life of the pavement. We recommend developing a regular Rachel Development, Inc. Project B2405314 February 17, 2025 Page 21 maintenance plan for filling cracks in exterior slabs and pavements to lessen the potential impacts for cold weather distress due to frost heave or warm weather distress due to wetting and softening of the subgrade. C.8. Utilities C.8.a. Subgrade Stabilization Earthwork activities associated with utility installations located inside building pad areas should adhere to the recommendations in Section C.2. For exterior utilities, we anticipate the soils at typical invert elevations will be suitable for utility support. However, if construction encounters unfavorable conditions such as soft clay, very loose silt, organic soils or perched water at invert grades, the unsuitable soils may require some additional subcutting and replacement with sand or crushed rock to prepare a proper subgrade for pipe support. Project design and construction should not place utilities within the 1H:1V oversizing of foundations. C.8.b. Selection, Placement, and Compaction of Backfill We recommend selecting, placing, and compacting utility backfill in accordance with the recommendations provided above in Section C.2.i. C.8.c. Corrosion Potential Based on our experience, some of the clayey soils encountered by the borings are moderately corrosive to metallic conduits. We recommend specifying non-corrosive materials or providing corrosion protection, unless project planning chooses to perform additional tests to demonstrate the soils are not corrosive. C.9. Stormwater Based on borings performed, the majority of onsite soils consist of clayey soils. These soils are consistent with Hydrologic Soil Group D of the Minnesota Stormwater Manual and not conducive to soil infiltration. While limited amounts of sand soils were encountered, we do not anticipate that significant quantities of these can be located for stormwater infiltration. For stormwater design, we recommend consulting the Minnesota Stormwater Manual. This Geotechnical Evaluation does not constitute a review of site suitability for stormwater infiltration or evaluate the potential impacts, if any, from infiltration of large amounts of stormwater. Rachel Development, Inc. Project B2405314 February 17, 2025 Page 22 D. Procedures D.1. Penetration Test Borings We drilled the penetration test borings on June 20, 2024, with an off-road-mounted core and auger drill equipped with hollow-stem auger. We performed the borings in general accordance with ASTM D6151 taking penetration test samples at 2 1/2- or 5-foot intervals in general accordance with ASTM D1586. The boring logs show the actual sample intervals and corresponding depths. We sealed penetration test boreholes meeting the Minnesota Department of Health (MDH) Environmental Borehole criteria with an MDH-approved grout, with sealing record submitted, as required. D.2. Exploration Logs D.2.a. Log of Boring Sheets The Appendix includes Log of Boring sheets for our penetration test borings. The logs identify and describe the penetrated geologic materials and present the results of penetration resistance and other in-situ tests performed. The logs also present the results of laboratory tests performed on penetration test samples, and groundwater measurements. We inferred strata boundaries from changes in the penetration test samples and the auger cuttings. Because we did not perform continuous sampling, the strata boundary depths are only approximate. The boundary depths likely vary away from the boring locations, and the boundaries themselves may occur as gradual rather than abrupt transitions. D.2.b. Log of Test Pit Sheets The Appendix also includes Log of Test Pit sheets. The logs classify and describe the geologic materials exposed in the sidewalls and bottoms of the pits, present the results of laboratory tests performed on bulk samples obtained from them, and depict groundwater measurements. D.2.c. Geologic Origins We assigned geologic origins to the materials shown on the logs and referenced within this report, based on: (1) a review of the background information and reference documents cited above, (2) visual classification of the various geologic material samples retrieved during the course of our subsurface exploration, (3) penetration resistance and other in-situ testing performed for the project, (4) laboratory test results, and (5) available common knowledge of the geologic processes and environments that have impacted the site and surrounding area in the past. Rachel Development, Inc. Project B2405314 February 17, 2025 Page 23 D.3. Material Classification and Testing D.3.a. Visual and Manual Classification We visually and manually classified the geologic materials encountered based on ASTM D2488. When we performed laboratory classification tests, we used the results to classify the geologic materials in accordance with ASTM D2487. The Appendix includes a chart explaining the classification system we used. D.3.b. Laboratory Testing The exploration logs in the Appendix note the results of the laboratory tests performed on geologic material samples. We performed the tests in general accordance with ASTM procedures. D.4. Groundwater Measurements The drillers checked for groundwater while advancing the penetration test borings, and again after auger withdrawal. We then immediately filled the boreholes, as described in our scope in our authorized scope of work and as noted on the boring log. E. Qualifications E.1. Variations in Subsurface Conditions E.1.a. Material Strata We developed our evaluation, analyses, and recommendations from a limited amount of site and subsurface information. It is not standard engineering practice to retrieve material samples from exploration locations continuously with depth. Therefore, we must infer strata boundaries and thicknesses to some extent. Strata boundaries may also be gradual transitions, and project planning should expect the strata to vary in depth, elevation, and thickness, away from the exploration locations. Variations in subsurface conditions present between exploration locations may not be revealed until performing additional exploration work or starting construction. If future activity for this project reveals any such variations, you should notify us so that we may reevaluate our recommendations. Such variations could increase construction costs, and we recommend including a contingency to accommodate them. Rachel Development, Inc. Project B2405314 February 17, 2025 Page 24 E.1.b. Groundwater Levels We made groundwater measurements under the conditions reported herein and shown on the exploration logs and interpreted in the text of this report. Note that the observation periods were relatively short, and project planning can expect groundwater levels to fluctuate in response to rainfall, flooding, irrigation, seasonal freezing and thawing, surface drainage modifications and other seasonal and annual factors. E.2. Continuity of Professional Responsibility E.2.a. Plan Review We based this report on a limited amount of information, and we made several assumptions to help us develop our recommendations. Braun Intertec should be retained to review the geotechnical aspects of the designs and specifications. This review will allow us to evaluate whether we anticipated the design correctly, if any design changes affect the validity of our recommendations, and if the design and specifications correctly interpret and implement our recommendations. Braun Intertec should also be retained to complete the soil observations and testing as the site is being graded. E.2.b. Construction Observations and Testing We recommend retaining Braun Intertec to perform the required observations and testing during construction as part of the ongoing geotechnical evaluation. This will allow us to correlate the subsurface conditions exposed during construction with those encountered by the borings and provide professional continuity from the design phase to the construction phase. If we do not perform observations and testing during construction, it becomes the responsibility of others to validate the assumption made during the preparation of this report and to accept the construction-related geotechnical engineer-of- record responsibilities. E.3. Use of Report This report is for the exclusive use of the addressed parties. Without written approval, we assume no responsibility to other parties regarding this report. Our evaluation, analyses and recommendations may not be appropriate for other parties or projects. E.4. Standard of Care In performing its services, Braun Intertec used that degree of care and skill ordinarily exercised under similar circumstances by reputable members of its profession currently practicing in the same locality. No warranty, express or implied, is made. Appendix EXPAND AND RESHAPE EXISTING POND 1 23 4 6 7 8 9 10 11 1213 14 15 16 17 18 19 5 1000' Shoreland Bndy 20078 sf 19452 sf 19130 sf 19462 sf ST-1ST-2 ST-5 ST-4 ST-3 ST-6 ST-7 ST-8POWERS BOULEVARDPLEASANTVI E W R O A D LAKE LUCY ROAD TROENDLE CIRCLENEZ PERCE DRIVEVINELAND COURT TP-8 TP-7 TP-6 TP-5 TP-4 TP-1 TP-3 TP-2 F:\2024\B2405314\CAD\B2405314.dwg,Geotech,1/27/2025 10:53:29 AMbraunintertec.com 952.995.2000 Minneapolis, MN 55438 11001 Hampshire Avenue S Project No: B2405314 Drawn By: Date Drawn: Checked By: Last Modified:1/27/25 Drawing No: Project Information Drawing Information B2405314 JAG 6/12/24 JLW Pleasant View Pointe Development 6535 Peaceful Lane Chanhassen, Minnesota Soil Boring Location SketchN DENOTES APPROXIMATE LOCATION OF TEST PIT 0 SCALE:1"= 150' 150'75' DENOTES APPROXIMATE LOCATION OF STANDARD PENETRATION TEST BORING Elev./ Depth ft 1007.3 1.0 1004.3 4.0 993.8 14.5 WaterLevelDescription of Materials (Soil-ASTM D2488 or 2487; Rock-USACE EM 1110-1-2908) CLAYEY SAND (SC), trace roots, dark brown, moist (TOPSOIL) LEAN CLAY (CL), brownish gray, moist, soft, rust staining (ALLUVIUM) CLAYEY SAND (SC), contains lenses of Poorly Graded Sand with Silt, trace Gravel, brown, moist, stiff to very stiff (GLACIAL TILL) END OF BORING Boring then backfilled with bentonite chips 5 10 15 20 25 30 SampleBlows (N-Value) Recovery 3-1-3 (4) 18" 3-8-5 (13) 18" 3-5-6 (11) 18" 3-4-8 (12) 18" 5-8-12-14 (20) 16" qₚ tsf MC % 25 Tests or Remarks Water not observed while drilling. LOG OF BORING See Descriptive Terminology sheet for explanation of abbreviations Project Number B2405314 Geotechnical Evaluation Pleasant View Pointe Development 6535 Peaceful Lane Chanhassen, Minnesota BORING:ST-1 LOCATION: Captured with RTK GPS. DATUM:NAD 1983 HARN Adj MN Carver (US Feet) NORTHING:190270.2 EASTING:557415.4 DRILLER:M Barber/C McClain LOGGED BY:J Carlson START DATE:06/20/24 END DATE:06/20/24 SURFACE ELEVATION:1008.3 ft RIG:GP-1 METHOD:3 1/4" HSA SURFACING:Grass WEATHER:Cloudy, 60°F B2405314 Braun Intertec Corporation Print Date:02/17/2025 ST-1 page 1 of 1DRAFT Elev./ Depth ft 1005.1 0.7 991.3 14.5 WaterLevelDescription of Materials (Soil-ASTM D2488 or 2487; Rock-USACE EM 1110-1-2908) SANDY LEAN CLAY (CL), trace roots, dark brown, moist (TOPSOIL) CLAYEY SAND (SC), trace Gravel, brown to grayish brown, moist, stiff, rust staining (GLACIAL TILL) END OF BORING Boring then backfilled with bentonite chips 5 10 15 20 25 30 SampleBlows (N-Value) Recovery 2-6-6 (12) 16" 4-7-7 (14) 16" 3-5-5 (10) 18" 3-5-8 (13) 15" 4-6-8-8 (14) 14" qₚ tsf MC % 18 Tests or Remarks Water not observed while drilling. LOG OF BORING See Descriptive Terminology sheet for explanation of abbreviations Project Number B2405314 Geotechnical Evaluation Pleasant View Pointe Development 6535 Peaceful Lane Chanhassen, Minnesota BORING:ST-2 LOCATION: Captured with RTK GPS. DATUM:NAD 1983 HARN Adj MN Carver (US Feet) NORTHING:190272.8 EASTING:557267.9 DRILLER:M Barber/C McClain LOGGED BY:J Carlson START DATE:06/20/24 END DATE:06/20/24 SURFACE ELEVATION:1005.8 ft RIG:GP-1 METHOD:3 1/4" HSA SURFACING:Grass WEATHER:Cloudy, 60°F B2405314 Braun Intertec Corporation Print Date:02/17/2025 ST-2 page 1 of 1DRAFT Elev./ Depth ft 995.0 0.4 993.4 2.0 991.4 4.0 986.4 9.0 975.4 20.0 WaterLevelDescription of Materials (Soil-ASTM D2488 or 2487; Rock-USACE EM 1110-1-2908) SANDY LEAN CLAY (CL), trace roots, dark brown, moist (TOPSOIL FILL) FILL: CLAYEY SAND (SC), brown, moist ORGANIC SILT (OH), trace fibers, black, moist (SWAMP DEPOSIT) CLAYEY SAND (SC), trace Gravel, trace fibers, gray and brown, moist, very soft to soft (ALLUVIUM) CLAYEY SAND (SC), trace Gravel, gray and brown to gray, moist, medium to stiff (GLACIAL TILL) END OF BORING Boring then backfilled with bentonite chips 5 10 15 20 25 30 SampleBlows (N-Value) Recovery 0-2-3 (5) 18" 0-0-0 WOH/18" 18" 0-1-2 (3) 18" 1-3-3 (6) 18" 1-3-4 (7) 18" 3-5-7 (12) 18" 3-5-7 (12) 18" qₚ tsf MC % 20 Tests or Remarks Water not observed while drilling. LOG OF BORING See Descriptive Terminology sheet for explanation of abbreviations Project Number B2405314 Geotechnical Evaluation Pleasant View Pointe Development 6535 Peaceful Lane Chanhassen, Minnesota BORING:ST-3 LOCATION: Captured with RTK GPS. DATUM:NAD 1983 HARN Adj MN Carver (US Feet) NORTHING:190105.1 EASTING:557074.6 DRILLER:M Barber/C McClain LOGGED BY:J Carlson START DATE:06/20/24 END DATE:06/20/24 SURFACE ELEVATION:995.4 ft RIG:GP-1 METHOD:3 1/4" HSA SURFACING:Grass WEATHER:Cloudy, 60°F B2405314 Braun Intertec Corporation Print Date:02/17/2025 ST-3 page 1 of 1DRAFT Elev./ Depth ft 994.9 1.3 990.2 6.0 982.2 14.0 976.2 20.0 WaterLevelDescription of Materials (Soil-ASTM D2488 or 2487; Rock-USACE EM 1110-1-2908) CLAYEY SAND (SC), trace roots, dark brown, moist (TOPSOIL) ORGANIC SILT (OH), trace fibers, black, moist (SWAMP DEPOSIT) CLAYEY SAND (SC), trace Gravel, brownish gray, moist, very soft to medium (ALLUVIUM) CLAYEY SAND (SC), contains lenses of Poorly Graded Sand, trace Gravel, gray, moist, soft to stiff (GLACIAL TILL) END OF BORING Boring then backfilled with bentonite chips 5 10 15 20 25 30 SampleBlows (N-Value) Recovery 0-1-2 (3) 18" 0-3-2 (5) 18" 0-0-0 WOH/18" 16" 0-0-0 WOH/18" 18" 0-2-3 (5) 18" 0-1-3 (4) 18" 1-4-6 (10) 18" qₚ tsf MC % 23 Tests or Remarks Water not observed while drilling. LOG OF BORING See Descriptive Terminology sheet for explanation of abbreviations Project Number B2405314 Geotechnical Evaluation Pleasant View Pointe Development 6535 Peaceful Lane Chanhassen, Minnesota BORING:ST-4 LOCATION: Captured with RTK GPS. DATUM:NAD 1983 HARN Adj MN Carver (US Feet) NORTHING:190107.0 EASTING:556957.4 DRILLER:M Barber/C McClain LOGGED BY:J Carlson START DATE:06/20/24 END DATE:06/20/24 SURFACE ELEVATION:996.2 ft RIG:GP-1 METHOD:3 1/4" HSA SURFACING:Grass WEATHER:Cloudy, 60°F B2405314 Braun Intertec Corporation Print Date:02/17/2025 ST-4 page 1 of 1DRAFT Elev./ Depth ft 1008.9 0.5 1002.4 7.0 989.4 20.0 WaterLevelDescription of Materials (Soil-ASTM D2488 or 2487; Rock-USACE EM 1110-1-2908) SILTY SAND (SM), fine-grained, trace roots, dark brown, moist (TOPSOIL) CLAYEY SAND (SC), contains lenses and seams of Poorly Graded Sand, trace Gravel, brown, moist, very soft to soft (ALLUVIUM) CLAYEY SAND (SC), trace Gravel, brown to grayish brown, moist to wet, medium to stiff (GLACIAL TILL) END OF BORING Boring then backfilled with bentonite chips 5 10 15 20 25 30 SampleBlows (N-Value) Recovery 0-2-2 (4) 18" 0-0-0 WOH/18" 18" 3-4-5 (9) 18" 3-3-4 (7) 18" 3-4-6 (10) 18" 3-5-6 (11) 18" 4-5-6 (11) 18" qₚ tsf MC % 27 20 Tests or Remarks Water observed at 10.5 feet while drilling. Water observed at 17.5 feet at end of drilling. LOG OF BORING See Descriptive Terminology sheet for explanation of abbreviations Project Number B2405314 Geotechnical Evaluation Pleasant View Pointe Development 6535 Peaceful Lane Chanhassen, Minnesota BORING:ST-5 LOCATION: Captured with RTK GPS. DATUM:NAD 1983 HARN Adj MN Carver (US Feet) NORTHING:189997.3 EASTING:556926.7 DRILLER:M Barber/C McClain LOGGED BY:J Carlson START DATE:06/20/24 END DATE:06/20/24 SURFACE ELEVATION:1009.4 ft RIG:GP-1 METHOD:3 1/4" HSA SURFACING:Weed WEATHER:Cloudy, 60°F B2405314 Braun Intertec Corporation Print Date:02/17/2025 ST-5 page 1 of 1DRAFT Elev./ Depth ft 1020.8 0.4 1006.7 14.5 WaterLevelDescription of Materials (Soil-ASTM D2488 or 2487; Rock-USACE EM 1110-1-2908) CLAYEY SAND (SC), trace roots, dark brown, moist (TOPSOIL) CLAYEY SAND (SC), contains lenses of Poorly Graded Sand, trace Gravel, brown and gray, moist, medium to stiff (GLACIAL TILL) END OF BORING Boring then backfilled with bentonite chips 5 10 15 20 25 30 SampleBlows (N-Value) Recovery 0-2-3 (5) 18" 2-4-6 (10) 18" 3-4-6 (10) 18" 4-6-10 (16) 18" 6-14-14 (28) 18" qₚ tsf MC % 17 Tests or Remarks Water not observed while drilling. LOG OF BORING See Descriptive Terminology sheet for explanation of abbreviations Project Number B2405314 Geotechnical Evaluation Pleasant View Pointe Development 6535 Peaceful Lane Chanhassen, Minnesota BORING:ST-6 LOCATION: Captured with RTK GPS. DATUM:NAD 1983 HARN Adj MN Carver (US Feet) NORTHING:189725.8 EASTING:557003.4 DRILLER:M Barber/C McClain LOGGED BY:J Carlson START DATE:06/20/24 END DATE:06/20/24 SURFACE ELEVATION:1021.2 ft RIG:GP-1 METHOD:3 1/4" HSA SURFACING:Grass WEATHER:Cloudy, 60°F B2405314 Braun Intertec Corporation Print Date:02/17/2025 ST-6 page 1 of 1DRAFT Elev./ Depth ft 1024.7 0.8 1011.1 14.5 WaterLevelDescription of Materials (Soil-ASTM D2488 or 2487; Rock-USACE EM 1110-1-2908) CLAYEY SAND (SC), trace roots, dark brown, moist (TOPSOIL) CLAYEY SAND (SC), contains lenses of Poorly Graded Sand, trace Gravel, brown and gray to brown, moist, medium to very stiff (GLACIAL TILL) END OF BORING Boring then backfilled with bentonite chips 5 10 15 20 25 30 SampleBlows (N-Value) Recovery 1-2-3 (5) 7" 0-3-4 (7) 18" 2-4-5 (9) 18" 1-4-5 (9) 18" 8-9-11-11 (20) 24" qₚ tsf MC % 20 Tests or Remarks Water not observed while drilling. LOG OF BORING See Descriptive Terminology sheet for explanation of abbreviations Project Number B2405314 Geotechnical Evaluation Pleasant View Pointe Development 6535 Peaceful Lane Chanhassen, Minnesota BORING:ST-7 LOCATION: Captured with RTK GPS. DATUM:NAD 1983 HARN Adj MN Carver (US Feet) NORTHING:189625.4 EASTING:556911.9 DRILLER:M Barber/C McClain LOGGED BY:J Carlson START DATE:06/20/24 END DATE:06/20/24 SURFACE ELEVATION:1025.6 ft RIG:GP-1 METHOD:3 1/4" HSA SURFACING:Grass WEATHER:Cloudy, 60°F B2405314 Braun Intertec Corporation Print Date:02/17/2025 ST-7 page 1 of 1DRAFT Elev./ Depth ft 1022.1 1.2 1019.3 4.0 1014.3 9.0 1008.8 14.5 WaterLevelDescription of Materials (Soil-ASTM D2488 or 2487; Rock-USACE EM 1110-1-2908) CLAYEY SAND (SC), trace roots, dark brown, moist (TOPSOIL) SANDY LEAN CLAY (CL), brown, moist, medium, rust staining (ALLUVIUM) SANDY LEAN CLAY (CL), trace Gravel, brown, moist, medium to stiff (GLACIAL TILL) CLAYEY SAND (SC), trace Gravel, brown, moist, stiff to very stiff (GLACIAL TILL) END OF BORING Boring then backfilled with bentonite chips 5 10 15 20 25 30 SampleBlows (N-Value) Recovery 1-2-3 (5) 18" 2-2-4 (6) 18" 3-4-5 (9) 18" 4-5-8 (13) 18" 4-7-14 (21) 18" qₚ tsf MC % 18 Tests or Remarks Water not observed while drilling. LOG OF BORING See Descriptive Terminology sheet for explanation of abbreviations Project Number B2405314 Geotechnical Evaluation Pleasant View Pointe Development 6535 Peaceful Lane Chanhassen, Minnesota BORING:ST-8 LOCATION: Captured with RTK GPS. DATUM:NAD 1983 HARN Adj MN Carver (US Feet) NORTHING:189356.8 EASTING:556921.9 DRILLER:M Barber/C McClain LOGGED BY:J Carlson START DATE:06/20/24 END DATE:06/20/24 SURFACE ELEVATION:1023.3 ft RIG:GP-1 METHOD:3 1/4" HSA SURFACING:Grass WEATHER:Cloudy, 60°F B2405314 Braun Intertec Corporation Print Date:02/17/2025 ST-8 page 1 of 1DRAFT Elev./ Depth ft 1002.1 1.0 995.1 8.0 992.1 11.0 WaterLevelDescription of Materials (Soil-ASTM D2488 or 2487) CLAYEY SAND (SC), trace roots, dark brown, frozen (moist when thawed) (TOPSOIL FILL) FILL: CLAYEY SAND (SC), trace Gravel, brown, moist CLAYEY SAND (SC), trace Gravel, with SILTY SAND layers, mottled brown, moist (GLACIAL TILL) END OF TEST PIT Test pit then backfilled with spoils 5 10 SampleSample Blows Recovery qₚ tsf MC %Tests or Remarks Surface elevations provided by Rachel Development Water not observed while excavating. LOG OF TEST PIT See Descriptive Terminology sheet for explanation of abbreviations Project Number B2405314 Geotechnical Evaluation Pleasant View Pointe Development 6535 Peaceful Lane Chanhassen, Minnesota TEST PIT:TP-1 LOCATION: See attached sketch DATUM: NORTHING:EASTING: EXCAVATOR:Rachel Contracting LOGGED BY:J Carlson START DATE:01/08/25 END DATE:01/08/25 SURFACE ELEVATION:1003.1 ft RIG:Excavator SURFACING:Topsoil WEATHER:Sun, 10°F B2405314 Braun Intertec Corporation Print Date:02/17/2025 TP-1 page 1 of 1DRAFT Elev./ Depth ft 995.1 1.0 990.1 6.0 983.1 13.0 981.1 15.0 WaterLevelDescription of Materials (Soil-ASTM D2488 or 2487) SILTY SAND (SM), trace roots, dark brown, frozen (moist when thawed) (TOPSOIL FILL) ORGANIC CLAY (OH), black, moist (SWAMP DEPOSIT) LEAN CLAY (CL), gray, moist, soft (ALLUVIUM) SANDY LEAN CLAY (CL), trace Gravel, brown, moist (GLACIAL TILL) END OF TEST PIT Test pit then backfilled with spoils 5 10 SampleSample Blows Recovery qₚ tsf MC %Tests or Remarks Too much steam to evaluate groundwater LOG OF TEST PIT See Descriptive Terminology sheet for explanation of abbreviations Project Number B2405314 Geotechnical Evaluation Pleasant View Pointe Development 6535 Peaceful Lane Chanhassen, Minnesota TEST PIT:TP-2 LOCATION: See attached sketch DATUM: NORTHING:EASTING: EXCAVATOR:Rachel Contracting LOGGED BY:J Carlson START DATE:01/08/25 END DATE:01/08/25 SURFACE ELEVATION:996.1 ft RIG:Excavator SURFACING:Topsol WEATHER:Sun, 10°F B2405314 Braun Intertec Corporation Print Date:02/17/2025 TP-2 page 1 of 1DRAFT Elev./ Depth ft 1004.5 1.0 992.5 13.0 991.5 14.0 WaterLevelDescription of Materials (Soil-ASTM D2488 or 2487) SANDY LEAN CLAY (CL), trace roots, dark brown, frozen (moist when thawed) (TOPSOIL FILL) FILL: SANDY LEAN CLAY (CL), trace Gravel, brown and dark brown, moist SANDY LEAN CLAY (CL), trace Gravel, mottled brown, moist (GLACIAL TILL) END OF TEST PIT Test pit then backfilled with spoils 5 10 SampleSample Blows Recovery qₚ tsf MC %Tests or Remarks Water not observed while excavating. LOG OF TEST PIT See Descriptive Terminology sheet for explanation of abbreviations Project Number B2405314 Geotechnical Evaluation Pleasant View Pointe Development 6535 Peaceful Lane Chanhassen, Minnesota TEST PIT:TP-3 LOCATION: See attached sketch DATUM: NORTHING:EASTING: EXCAVATOR:Rachel Contracting LOGGED BY:J Carlson START DATE:01/08/25 END DATE:01/08/25 SURFACE ELEVATION:1005.5 ft RIG:Excavator SURFACING:Topsoil WEATHER:Sun, 10°F B2405314 Braun Intertec Corporation Print Date:02/17/2025 TP-3 page 1 of 1DRAFT Elev./ Depth ft 1016.9 1.5 1012.4 6.0 WaterLevelDescription of Materials (Soil-ASTM D2488 or 2487) SANDY LEAN CLAY (CL), trace roots, dark brown, frozen (moist when thawed) (TOPSOIL) SANDY LEAN CLAY (CL), trace Gravel, brown, moist (GLACIAL TILL) END OF TEST PIT Test pit then backfilled with spoils 5 10 SampleSample Blows Recovery qₚ tsf MC %Tests or Remarks Water not observed while excavating. LOG OF TEST PIT See Descriptive Terminology sheet for explanation of abbreviations Project Number B2405314 Geotechnical Evaluation Pleasant View Pointe Development 6535 Peaceful Lane Chanhassen, Minnesota TEST PIT:TP-4 LOCATION: See attached sketch DATUM: NORTHING:EASTING: EXCAVATOR:Rachel Contracting LOGGED BY:J Carlson START DATE:01/08/25 END DATE:01/08/25 SURFACE ELEVATION:1018.4 ft RIG:Excavator SURFACING:Topsoil WEATHER:Sun, 10°F B2405314 Braun Intertec Corporation Print Date:02/17/2025 TP-4 page 1 of 1DRAFT Elev./ Depth ft 999.1 2.0 995.1 6.0 WaterLevelDescription of Materials (Soil-ASTM D2488 or 2487) CLAYEY SAND (SC), trace roots, dark brown, frozen (moist when thawed) (TOPSOIL) CLAYEY SAND (SC), trace Gravel, brown, moist (GLACIAL TILL) END OF TEST PIT Test pit then backfilled with spoils 5 10 SampleSample Blows Recovery qₚ tsf MC %Tests or Remarks Water not observed while excavating. LOG OF TEST PIT See Descriptive Terminology sheet for explanation of abbreviations Project Number B2405314 Geotechnical Evaluation Pleasant View Pointe Development 6535 Peaceful Lane Chanhassen, Minnesota TEST PIT:TP-5 LOCATION: See attached sketch DATUM: NORTHING:EASTING: EXCAVATOR:Rachel Contracting LOGGED BY:J Carlson START DATE:01/08/25 END DATE:01/08/25 SURFACE ELEVATION:1001.1 ft RIG:Excavator SURFACING:Topsoil WEATHER:Sun, 10°F B2405314 Braun Intertec Corporation Print Date:02/17/2025 TP-5 page 1 of 1DRAFT Elev./ Depth ft 1009.4 0.5 1006.9 3.0 1001.9 8.0 WaterLevelDescription of Materials (Soil-ASTM D2488 or 2487) CLAYEY SAND (SC), trace roots, dark brown, frozen (moist when thawed) (TOPSOIL FILL) FILL: CLAYEY SAND (SC), trace Gravel, dark brown, moist CLAYEY SAND (SC), trace Gravel, brown, moist (GLACIAL TILL) END OF TEST PIT Test pit then backfilled with spoils 5 10 SampleSample Blows Recovery qₚ tsf MC %Tests or Remarks Water not observed while excavating. LOG OF TEST PIT See Descriptive Terminology sheet for explanation of abbreviations Project Number B2405314 Geotechnical Evaluation Pleasant View Pointe Development 6535 Peaceful Lane Chanhassen, Minnesota TEST PIT:TP-6 LOCATION: See attached sketch DATUM: NORTHING:EASTING: EXCAVATOR:Rachel Contracting LOGGED BY:J Carlson START DATE:01/08/25 END DATE:01/08/25 SURFACE ELEVATION:1009.9 ft RIG:Excavator SURFACING:Topsoi WEATHER:Sun, 10°F B2405314 Braun Intertec Corporation Print Date:02/17/2025 TP-6 page 1 of 1DRAFT Elev./ Depth ft 1015.4 4.0 1013.4 6.0 WaterLevelDescription of Materials (Soil-ASTM D2488 or 2487) CLAYEY SAND (SC), trace roots, dark brown, frozen (moist when thawed) (TOPSOIL FILL) CLAYEY SAND (SC), trace Gravel, brown, moist (GLACIAL TILL) END OF TEST PIT Test pit then backfilled with spoils 5 10 SampleSample Blows Recovery qₚ tsf MC %Tests or Remarks Water not observed while excavating. LOG OF TEST PIT See Descriptive Terminology sheet for explanation of abbreviations Project Number B2405314 Geotechnical Evaluation Pleasant View Pointe Development 6535 Peaceful Lane Chanhassen, Minnesota TEST PIT:TP-7 LOCATION: See attached sketch DATUM: NORTHING:EASTING: EXCAVATOR:Rachel Contracting LOGGED BY:J Carlson START DATE:01/08/25 END DATE:01/08/25 SURFACE ELEVATION:1019.4 ft RIG:Excavator SURFACING:Topsoil WEATHER:Sun, 10°F B2405314 Braun Intertec Corporation Print Date:02/17/2025 TP-7 page 1 of 1DRAFT Elev./ Depth ft 1040.1 0.5 1035.6 5.0 WaterLevelDescription of Materials (Soil-ASTM D2488 or 2487) CLAYEY SAND (SC), trace roots, dark brown, frozen (moist when thawed) (TOPSOIL) CLAYEY SAND (SC), trace Gravel, brown, moist (GLACIAL TILL) END OF TEST PIT Test pit then backfilled with spoils 5 10 SampleSample Blows Recovery qₚ tsf MC %Tests or Remarks Water not observed while excavating. LOG OF TEST PIT See Descriptive Terminology sheet for explanation of abbreviations Project Number B2405314 Geotechnical Evaluation Pleasant View Pointe Development 6535 Peaceful Lane Chanhassen, Minnesota TEST PIT:TP-8 LOCATION: See attached sketch DATUM: NORTHING:EASTING: EXCAVATOR:Rachel Contracting LOGGED BY:J Carlson START DATE:01/08/25 END DATE:01/08/25 SURFACE ELEVATION:1040.6 ft RIG:Excavator SURFACING:Topsoil WEATHER:Sun, 10°F B2405314 Braun Intertec Corporation Print Date:02/17/2025 TP-8 page 1 of 1DRAFT Descriptive Terminology of Soil Based on Standards ASTM D2487/2488 (Unified Soil Classification System) Group Symbol Group NameB Cu ≥ 4 and 1 ≤ Cc ≤ 3D GW Well‐graded gravelE Cu < 4 and/or (Cc < 1 or Cc > 3)D GP Poorly graded gravelE Fines classify as ML or MH GM Silty gravelE F G Fines Classify as CL or CH GC Clayey gravelE F G Cu ≥ 6 and 1 ≤ Cc ≤ 3D SW Well‐graded sandI Cu < 6 and/or (Cc < 1 or Cc > 3)D SP Poorly graded sandI Fines classify as ML or MH SM Silty sandF G I Fines classify as CL or CH SC Clayey sandF G I CL Lean clayK L M PI < 4 or plots below "A" lineJ ML SiltK L M Organic OL CH Fat clayK L M MH Elastic siltK L M Organic OH PT Peat Highly Organic Soils Silts and Clays (Liquid limit less than 50) Silts and Clays (Liquid limit 50 or more) Primarily organic matter, dark in color, and organic odor Inorganic Inorganic PI > 7 and plots on or above "A" lineJ PI plots on or above "A" line PI plots below "A" line Criteria for Assigning Group Symbols and Group Names Using Laboratory TestsA Soil Classification Coarse‐grained Soils (more than 50% retained on No. 200 sieve)Fine‐grained Soils (50% or more passes the No. 200 sieve) Sands (50% or more coarse fraction passes No. 4 sieve) Clean Gravels (Less than 5% finesC) Gravels with Fines (More than 12% finesC) Clean Sands (Less than 5% finesH) Sands with Fines (More than 12% finesH) Gravels (More than 50% of coarse fraction retained on No. 4 sieve) Liquid Limit − oven dried Liquid Limit − not dried <0.75 Organic clay K L M N Organic silt K L M O Liquid Limit − oven dried Liquid Limit − not dried <0.75 Organic clay K L M P Organic silt K L M Q ParticleSize Identification Boulders.............. over 12" Cobbles................ 3" to 12" Gravel Coarse............. 3/4" to 3" (19.00 mm to 75.00 mm) Fine................. No. 4 to 3/4" (4.75 mm to 19.00 mm) Sand Coarse.............. No. 10 to No. 4 (2.00 mm to 4.75 mm) Medium........... No. 40 to No. 10 (0.425 mm to 2.00 mm) Fine.................. No. 200 to No. 40 (0.075 mm to 0.425 mm) Silt........................ No. 200 (0.075 mm) to .005 mm Clay...................... < .005 mm Relative ProportionsL, M trace............................. 0 to 5% little.............................. 6 to 14% with.............................. ≥ 15% Inclusion Thicknesses lens............................... 0 to 1/8" seam............................. 1/8" to 1" layer.............................. over 1" Apparent Relative Density of Cohesionless Soils Very loose ..................... 0 to 4 BPF Loose ............................ 5 to 10 BPF Medium dense.............. 11 to 30 BPF Dense............................ 31 to 50 BPF Very dense.................... over 50 BPF A. Based on the material passing the 3‐inch (75‐mm) sieve. B. If field sample contained cobbles or boulders, or both, add "with cobbles or boulders, or both" to group name. C. Gravels with 5 to 12% fines require dual symbols: GW‐GM well‐graded gravel with silt GW‐GC well‐graded gravel with clay GP‐GM poorly graded gravel with silt GP‐GC poorly graded gravel with clay D. Cu = D60 / D10 Cc = 𝐷30 2 / ሺ𝐷10 𝑥 𝐷60) E. If soil contains ≥ 15% sand, add "with sand" to group name. F. If fines classify as CL‐ML, use dual symbol GC‐GM or SC‐SM. G. If fines are organic, add "with organic fines" to group name. H. Sands with 5 to 12% fines require dual symbols: SW‐SM well‐graded sand with silt SW‐SC well‐graded sand with clay SP‐SM poorly graded sand with silt SP‐SC poorly graded sand with clay I. If soil contains ≥ 15% gravel, add "with gravel" to group name. J. If Atterberg limits plot in hatched area, soil is CL‐ML, silty clay. K. If soil contains 15 to < 30% plus No. 200, add "with sand" or "with gravel", whichever is predominant. L. If soil contains ≥ 30% plus No. 200, predominantly sand, add “sandy” to group name. M. If soil contains ≥ 30% plus No. 200 predominantly gravel, add “gravelly” to group name. N. PI ≥ 4 and plots on or above “A” line. O. PI < 4 or plots below “A” line. P. PI plots on or above “A” line. Q. PI plots below “A” line. Laboratory Tests DD Dry density,pcf qp Pocket penetrometer strength, tsf WD Wet density, pcf qU Unconfined compression test, tsf P200 % Passing #200 sieve LL Liquid limit MC Moisture content, %PL Plastic limit OC Organic content, %PI Plasticity index Consistency of Blows Approximate Unconfined Cohesive Soils Per Foot Compressive Strength Very soft................... 0 to 1 BPF................... < 0.25 tsf Soft........................... 2 to 4 BPF................... 0.25 to 0.5 tsf Medium.................... 5to 8 BPF .................. 0.5 to 1 tsf Stiff........................... 9 to 15 BPF................. 1 to 2 tsf Very Stiff................... 16 to 30 BPF............... 2 to 4 tsf Hard.......................... over 30 BPF................ > 4 tsf Drilling Notes: Blows/N‐value: Blows indicatethe driving resistance recorded for each 6‐inch interval. The reported N‐value is the blows per foot recorded by summing the second and third interval in accordance with the Standard Penetration Test, ASTM D1586. PartialPenetration:If the sampler could not be driven through a full 6‐inch interval, the number of blows for that partial penetration is shown as #/x" (i.e. 50/2"). The N‐value is reported as "REF" indicating refusal. Recovery: Indicates the inches of sample recovered from the sampled interval. For a standard penetration test, full recovery is 18", and is 24" for a thinwall/shelby tube sample. WOH: Indicates the sampler penetrated soil under weight of hammer and rods alone; driving not required. WOR: Indicates the sampler penetrated soil under weight of rods alone; hammer weight and driving not required. Water Level: Indicates the water level measured by the drillers either while drilling ( ), at the end of drilling ( ), or at some time after drilling ( ). Moisture Content: Dry:Absence of moisture, dusty, dry to the touch. Moist: Damp but no visible water. Wet: Visible free water, usually soil is below water table. 5/2021 1 MINNEHAHA CREEK WATERSHED DISTRICT BOARD OF MANAGERS 5. STORMWATER MANAGEMENT RULE PURSUANT TO MINNESOTA STATUTES §103D.341 Adopted April 11, 2024 Effective April 29, 2024 1. POLICY. It is the policy of the Board of Managers to: a. Protect and improve the physical, chemical and ecological health of surface waters and groundwater within the District; b. Protect against local and regional flooding from land use change; c. Promote reduction of rainfall and stormwater runoff volume to improve water quality, maintain groundwater recharge, reduce flooding and promote the health of native and designed plant communities; d. For land disturbance subject to regulation under the National Pollutant Discharge Elimination Program, align local and state stormwater management requirements for clarity and efficiency. 2. APPLICABILITY. a. A permit under this rule is required for the following actions: 1. Development or a Linear Transportation Project that meets criteria for site size, extent of site disturbance and impervious surface change set forth in Table 1 and Table 2 of this rule. In applying Tables 1 and 2, the District will aggregate all activity that it finds to constitute a Common Plan of Development. 2. Subdivision of a tract at least one acre in size into three or more buildable lots. 3. Mass grading or otherwise changing land contours, except for agricultural activity, at a scale that may materially affect the direction, peak rate, volume or water quality of runoff. b. The following actions, even if subject to paragraph 2.a, do not require a permit if the amount of new and reconstructed impervious surface is less than one acre: 1. Single-family residential Development on an existing lot of record. 2 2. Construction of a sidewalk or trail not more than 12 feet in width, and bordered downgradient by pervious vegetated buffer averaging at least half the width of the sidewalk or trail. 3. Linear Transportation Projects where the net increase of impervious surface is <10,000 square feet. 4. Sites that reduce impervious surface by 10%. c. An action requiring a permit under paragraph a.2 that does not propose mass grading or the construction or reconstruction of impervious surface need not demonstrate that it meets the specific stormwater management criteria of this rule. The applicant must provide a conceptual stormwater management plan and the permit will require that subsequent land disturbance within the subdivided tract demonstrate compliance with specific rule criteria. d. An action requiring a permit under paragraph a.3 is not subject to section 3 of this rule. e. Surface material such as permeable pavement (asphalt, concrete, pavers), artificial turf, and playground surfacing that is designed to infiltrate stormwater when maintained is considered impervious surface for the purpose of section 2, but may be used as a volume-reduction practice in accordance with Appendix A. 3. VOLUME CONTROL. a. For purposes of both volume and phosphorus control, an applicant subject to this rule under paragraph 2.a.1 must provide volume reduction equal to the following. Volume reduction is to be calculated in accordance with Appendix A to this rule. 1. For Development, one inch times the area of impervious surface stated in Table 1. 2. For a Linear Transportation Project, either one inch times the area of new impervious surface, or one-half inch times the area of new and reconstructed impervious surface, whichever greater, except that if the total of new and reconstructed impervious surface is less than one acre, the volume is to be calculated only for the net increase in impervious surface as stated in Table 2. b. Volume reduction practices must be used to meet the subsection 3.a standard, to the extent feasible. An infiltration practice is prohibited in the following circumstances: 1. The area receives discharge from a vehicle fueling and maintenance area. 3 2. Contamination in soil or groundwater may be mobilized by the infiltrating stormwater. 3. Soils infiltration rate exceeds 8.3 inches per hour. 4. The separation between the bottom of the infiltration system and the elevation of seasonally saturated soils or top of bedrock is less than three feet. 5. Soils are predominantly Hydrologic Soil Group D (clay) or otherwise unreliable for infiltration. 6. The area is within an Emergency Response Area (ERA) in a Drinking Water Supply Management Area (DWSMA), as defined in Minnesota Rules 4720.5100, subpart 13, classified as high or very high vulnerability. 7. The area is within an ERA in a DWSMA classified as moderate vulnerability, or outside of an ERA in a DWSMA classified as high or very high vulnerability. This prohibition does not apply if an engineering evaluation, meeting standards in the Minnesota Stormwater Manual, demonstrates that the system will function and not have adverse impact on groundwater. 8. The area is within 50 feet of a drinking water well or within 100 feet of a sensitive public water supply well. 9. The area is within 1,000 feet upgradient, or 100 feet downgradient, of an active karst feature. 10. The area receives stormwater runoff from one of the following entities regulated under NPDES for industrial stormwater: automobile salvage yard; scrap recycling and waste recycling facility; hazardous waste treatment, storage, or disposal facility; air transportation facility that conducts deicing. To support a finding of infeasibility, the applicant must document the constraint and examine means to remove or avoid it including modifying the size, scope, configuration or density of the proposed action. To document contamination under paragraph 3.b.2, the permittee must complete the Minnesota Pollution Control Agency site screening assessment checklist, available in the Minnesota Stormwater Manual, or submit an independent assessment. c. If the required volume reduction cannot feasibly be provided by volume reduction practices listed in Appendix A, the applicant must incorporate filtration or other non- volume-reduction practices to achieve phosphorous control in an amount equivalent to that which would be achieved through the required volume reduction. Equivalent phosphorus control may be demonstrated by any technically accepted method, 4 including use of a removal rate stated in the Minnesota Stormwater manual. For a filtration practice, in place of specific demonstration, an applicant may treat twice the required volume reduction, as calculated in accordance with Appendix A to this rule. d. For a Linear Transportation Project, if the required volume reduction cannot be provided within existing right-of-way, the permittee must make a reasonable attempt to obtain additional right-of-way, easement or other permission to site the required volume. Volume reduction is not required to the extent it cannot be provided cost- effectively. If the volume reduction of paragraph 3.a.2 is not fully met, equivalent phosphorus control must be provided to the extent feasible. e. Runoff volume draining to a landlocked area may not increase during back-to-back 100- year storm events. 4. RATE CONTROL. a. An action may not increase the peak runoff rate from the site, in aggregate, for design storm events. An applicant proposing to increase peak runoff at a specific point of site discharge must demonstrate no adverse local impact on water resource values or infrastructure. Aggregate compliance for all site boundary discharge will be determined with respect to runoff not managed in a regional facility. b. For a tract being converted from row crop agriculture, the criterion of no increase applies as compared with an assumed existing meadow condition. 5. BEST MANAGEMENT PRACTICE (BMP). When a BMP is specified in Table 1 or 2, an applicant must incorporate an on-site structural or non-structural practice to achieve one or more of the following: limit impervious surface increase, reduce stormwater volume, reduce pollutant discharge, or control peak flow from the site. The permittee will select the BMP to address the impacts posed by the proposed action. The BMP must be designed and installed in accordance with the Minnesota Stormwater Manual and accepted engineering practice. 6. FLOOD SEPARATION. There must be two feet of vertical separation between the 100-year high water elevation of a waterbody or stormwater practice and the low opening of any structure, unless the structure opening is hydraulically disconnected from the waterbody or practice. 7. IMPACT ON DOWNGRADIENT WATERBODIES. a. A new point source must treat for sediment and phosphorus removal before discharge to a waterbody. This paragraph does not apply to changes in flow from an existing point source. 5 b. An action otherwise subject to this rule must meet the following criteria: Wetland Management Class/ Waterbody Permitted Bounce for Design Storm Events Inundation Period for 1- or 2-Year Design Storm Event Inundation Period for 10- and 100-Year Design Storm Events Runout Control Elevation Preserve Existing Existing Existing No change Manage 1 Existing plus 0.5 feet Existing plus 1 day Existing plus 2 days No change Manage 2 Existing plus 1.0 feet Existing plus 2 days Existing plus 14 days 0 to 1.0 ft above existing runout Manage 3 No limit Existing plus 7 days Existing plus 21 days 0 to 4.0 ft above existing runout Lakes Existing N/A N/A No change 8. LOCATION OF VOLUME AND RATE CONTROL PRACTICES. a. A volume control practice is to be located on site, unless the applicant demonstrates that this is not cost-effective. An off-site practice must capture runoff from the regulated site impervious surface before it enters a receiving water, if practical, and otherwise before it enters a public water. A rate control practice may be located on- or offsite, but before runoff enters a public water. b. For use of an off-site facility, the applicant must incorporate an on-site BMP in accordance with section 5, above, and must demonstrate that there will be no adverse water resource impact upgradient of the facility. c. For use of an off-site regional facility, the applicant must demonstrate that the facility was designed and constructed to manage the stormwater runoff from the site, the applicant has permission to use the necessary part of facility capacity, the facility is subject to satisfactory maintenance obligations enforceable by the District, and its current maintenance conforms with those obligations. d. A public or private entity may construct a regional volume or rate control facility in advance of its use for compliance purposes. The facility’s terms of use will be stated in a regional facility plan approved by the District. 6 9. SUBMITTALS. a. The applicant must submit a plan, certified by a professional engineer registered in the State of Minnesota, to the District. The plan must contain the following: 1. Property lines of the tract or contiguous tracts under applicant’s ownership. 2. Delineation of subwatersheds that contribute runoff to the site, and of existing and proposed subwatersheds on the site. 3. Delineation of top of bank of existing on-site waterbodies and of floodplain, and notations of ordinary high-water level and 100-year high water elevation of on- site waterbodies. 4. Delineation of any flowage or drainage easements, or of other property interests dedicated to water management or conveyance. 5. Existing and proposed site elevations at two-foot intervals, related to National Geodetic Vertical Datum (NGVD), 1929 datum. 6. Locations, alignments, and elevations of existing and proposed stormwater management facilities, as well as construction plans and specifications for all proposed facilities. 7. All hydrologic, hydraulic and water quality computations on which the design of proposed stormwater management facilities is based, including (i) runoff volume abstractions; and (ii) stormwater runoff volume and rate analyses for design storm events, for existing and proposed conditions, at each point of site discharge. For the purpose of this rule, “design storm events” means either the one- or two-year, 24-hour event, as the applicant selects, as well as the 10- and 100-year, 24-hour events. b. If proposing to meet this rule by infiltration through site soils, the applicant must characterize soils by use of a method identified in the Minnesota Stormwater Manual, and must document the characterization and the methodology used. c. If proposing that infiltration is infeasible, the applicant must provide supporting documentation in accordance with subsection 3.b. d. If proposing soil amendment, the applicant must submit a soil amendment plan for District approval. e. If proposing capture and reuse, the applicant must submit a system operating plan and calculations that quantify the benefits of the reuse system. 7 f. The applicant must document application for a National Pollutant Discharge Elimination System (NPDES) permit, if applicable. 10. STORMWATER FACILITY CONSTRUCTION AND MAINTENANCE. a. Stormwater management facilities must be constructed and functional within 24 months of the start of construction of regulated impervious surface. b. A stormwater management facility must be designed for maintenance access and maintained in perpetuity to function as designed. c. As a condition of permit issuance, a permittee must sign and record on the title a declaration or other instrument, in a form supplied by the District or otherwise acceptable to it, that provides for perpetual facility maintenance. A public permittee, in place of a recorded instrument, may enter into a signed agreement with the District by which the permittee assumes permanent maintenance responsibility. d. A public entity may assume responsibility to maintain a stormwater facility on private property either by: (1) being a signatory to the private-party declaration; or (2) entering into a signed agreement with the District and separately establishing, by means acceptable to the District, its perpetual right to enter the property. 11. FINANCIAL ASSURANCE. A bond, letter of credit or cash escrow in accordance with the District's Financial Assurances rule is a condition of permit issuance. Conditions for release of the financial assurance include, but are not limited to, the applicant’s submittal of certified as-built drawings for structural stormwater management practices. 8 Table 2: Requirements for Linear Transportation Projects New and reconstructed impervious area Net increase in impervious area Requirement < 1 acre 10,000 sf - 1 acre Volume from net added impervious surface, Rate ≥ 1 acre < 10,000 sf Volume equal to the larger of: one inch of volume from new impervious surface OR 0.5 inches of volume from new impervious and reconstructed impervious surface ≥ 10,000 sf Volume equal to the larger of: one inch of volume from new impervious surface OR 0.5 inches of volume from new impervious and reconstructed impervious surface, Rate Table 1: Requirements for Development Site Size New and fully reconstructed impervious area Site Disturbance Impervious Surface Change* Requirement < 1 acre > 0 sq ft - 0-9% decrease or any increase BMP ≥ 1 acre < 1 acre < 40% 0 - 9% decrease BMP > 0 - < 50% increase Volume from net added impervious surface, Rate ≥ 50% increase Volume from entire site impervious surface, Rate ≥ 1 acre < 40% < 50% increase Volume from new and fully reconstructed impervious surface, Rate ≥ 50% increase Volume from entire site impervious surface, Rate - ≥ 40% - Volume from entire site impervious surface, Rate *For sites with no existing impervious on-site, impervious surface change = proposed site impervious surface (percent) 9 APPENDIX A: Volume Reduction Practice Credit Schedule Practice Design Guidance Volume Control (VC) Credit Calculation Methods Surface Infiltration Basin Minnesota Stormwater Manual Volume provided VC= Volume below overflow elevation (1) Underground Infiltration Trench Minnesota Stormwater Manual Void volume provided VC = Volume below overflow elevation (1) Capture and Reuse of Stormwater Submit pump design plans and hydrologic calculations Volume capacity to capture and reuse runoff from a 1- inch rainfall event Submit operating plan and calculations for reuse system to document annual volume reuse during dry, wet, and average years Permeable Surface Minnesota Stormwater Manual 1-inch credit over the surface area VC = 1/12 x area of permeable surface Soil Amendment(s)(2) Minnesota Stormwater Manual 0.5-inch credit over the area of soil amendment area (3) VC = 0.5/12 x area of soil amendment Non-Volume-Reduction Practice Credit Schedule(4) Practice Design Guidance Phosphorus Control (PC) Credit Calculation Methods Filtration Minnesota Stormwater Manual Volume provided (must be twice the required volume reduction) (5) PC = Volume below overflow elevation (filtered volume is not considered) (1) Volume infiltrated during a rainfall event shall not be credited towards the volume reduction requirement. This is a simple approach for designers and for reviewers to verify conformance to the standard; a stormwater mo del is not needed for calculations. This is a conservative assumption because infiltration of stormwater in Minnesota is an evolvin g practice. MCWD will continue to research current trends, collect and analyze monitoring data, and utilize modeling and engi neering methods to assess the effectiveness of the standards to achieve the water quality goals of the District. (2) This method is considered as a volume reduction practice only for an application that proposes less than an acre of new or fully reconstructed impervious area. (3) For SCS TR-55 cover type “open space (lawns),” compacted soil (HSG C, curve number 74) begins to generate runoff with a 0.9 -inch rainfall. A HSG B soil (curve number 61) begins to generate runoff with a 1.5 -inch rainfall. Therefore, preserving the infiltration capacity of HSG B soil through the use of soil amendments yields an approximate 0.5 -inch volume reduction credit. (4) Other non-volume-reduction practices not listed in this table may be used. Equivalent phosphorus control must be demonstrated in accordance with subsection 3(c) of this rule . (5) The Minnesota Stormwater Manual reports that nutrient removal (total phosphorus) is approximately half as effective for filtr ation as infiltration.