Loading...
HomeMy WebLinkAbout2025-07-25 Storm Water Management Plan Storm Water Management Plan Calculations & Summaries Central Automotive Parking Lot Addition Project No. 18711 July 25, 2025 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. _____________________________________________ Drew Messmer, P.E. Reg. No. 62823 Prepared By: Prepared For: Anderson Engineering of MN, LLC David Triemert 13605 1st Avenue North, Suite 100 Central Automotive Plymouth, MN 55441 14819 59th Street North Ph: 763.412.4000 Stillwater, MN 55082 Fax: 763.412.4090 Ph: 651.439.9324 Anderson Engineering of Minnesota, LLC ● 13605 1st Avenue North, Suite 100 ● Plymouth, Minnesota 55441 ● (763) 412-4000 Main ● (763) 412-4090 Fax ● www.ae-mn.com 1 | P a g e Table of Contents · Cover / Certification Page · Table of Contents · Project Overview · Existing Site Conditions · Soils · Proposed Site Conditions · Methodology · Summary Appendix – Exhibits and Calculations · A – Existing Drainage Map · B – Proposed Drainage Map · C – Pre & Post Conditions HydroCAD Reports · D – NOAA Atlas 14 Precipitation Data · E – Grading, Drainage, & Erosion Control Plan · F – NRCS Web Soil Survey · G – SHSAM Water Quality Analysis Summary Stormwater Narrative/Summary July 25, 2025 Central Automotive Parking Lot Addition Oak Park Heights, MN 2 | P a g e Project Overview Construction of the new parking lot addition for the existing repair shop is located at 14819 59th St N, Oak Park Heights, Minnesota 55082. The project is located in the NE1/4 of NE1/4 of Sec. 4, T29N, R20W in Washington County, and lies within the boundaries of the Middle St. Croix Watershed Management Organization (MSCWMO). This report is prepared based on MSCWMO rules & regulations. The project includes site clearing and demolishing of minor existing woodland, construction of an approximate 12,000 SF bituminous parking lot facility, and proposed expansion of the existing stormwater pond, located east of the existing repair shop facility, to accommodate the proposed parking lot addition’s increased impervious coverage for the site. Existing Site Conditions The 2.61-acre property is bounded by 59th St. to the north and Osgood Avenue North to the west. The area designated for the proposed parking lot addition is currently covered in woodland terrain, primarily in the eastern and southeastern portions of the site. The existing topography in this area of the site generally drains to the southeast. See Exhibit A – Existing Drainage Map, for existing topography, drainage, and sub-catchment areas. Soils The preliminary analysis of site soil types on this project should be Hydraulic Soil Type B, primarily silt loam. This preliminary soil classification is based upon the Washington County web soil survey found at the USDA website (See Exhibit F – NRCS Web Soil Survey). Slopes in the area designated for the proposed parking lot addition typically range from 5-20% creating a gentle rolling landscape, with a few eastern woodland areas approaching and exceeding 2:1 slopes. Proposed Site Conditions The development will consist of constructing an approximate 12,000 SF bituminous parking lot addition and proposed expansion of the existing stormwater pond, to accommodate the increased impervious coverage for the site. The site’s total impervious coverage area would increase to equal approximately 35,500 SF. The proposed drainage pattern will be somewhat unchanged. The parking lot drainage will be conveyed via storm sewer, and outlet into a proposed expanded infiltration basin. Pre-treatment prior to entering the infiltration basin will be accomplished via sump manhole with a SAFL baffle. The existing infiltration basin outlets into a storm sewer that will tie-in to an existing stub roughly 220 feet north of the basin. The proposed sub-watersheds have been depicted on Exhibit B – Proposed Drainage Map attached in the appendix of this report. Stormwater Narrative/Summary July 25, 2025 Central Automotive Parking Lot Addition Oak Park Heights, MN 3 | P a g e Methodology Erosion and Sediment Control Exhibit E: Civil Sheet CG101 - Grading, Drainage, & Erosion Control Plan of the accompanying plan-set depicts the temporary and permanent sediment control practices employed, which include; Silt Fencing, Inlet Filter Sacks, Construction Entrance, Erosion Blanket, Rip-Rap, and a Concrete Wash Area, as shown on the drawings. HydroCAD The hydrologic characteristics of the site were modeled using HydroCAD software. TR55/TR20 methods were utilized. Existing and proposed drainage areas were determined via review of current land survey data and aerial photos. The 2, 10, & 100-year frequency events were analyzed for peak runoff rate control in the existing and proposed conditions. The current NOAA Atlas 14 rainfall frequencies for the location were used. Depths for the 2, 10, & 100-year storms were found to be 2.81”, 4.17”, and 7.20” respectively (See Exhibit D – NOAA Atlas 14 Precipitation Data). Runoff from pervious and impervious surfaces were calculated separately to more accurately model the runoff volume from the site surfaces. Results of this analysis are summarized in Table 1 below, and a report can be seen in Exhibit C – Pre & Post Conditions HydroCAD Reports. Table 1: Existing vs. Proposed Runoff Rates Reach ID Storm Event Existing Rate (CFS) Post Development Rate (CFS) R-1 2YR – 2.81” 0.19 0.20 10YR – 4.17” 0.76 1.09 100YR – 7.20” 3.50 3.79 R-2 2YR – 2.81” 0.33 0.27 10YR – 4.17” 1.51 1.19 100YR – 7.20” 5.27 4.14 R-3 2YR – 2.81” 0.12 0.12 10YR – 4.17” 0.53 0.52 100YR – 7.20” 1.81 1.77 TOTAL 2YR – 2.81” 0.64 0.59 10YR – 4.17” 2.80 2.80 100YR – 7.20” 10.58 9.70 Infiltration Basin For this project, we have proposed an infiltration basin. Site soils have been determined to be silty loams underlain with loamy sands in Hydrologic Soil Group B with a design infiltration rate of 0.3 inches/hr. The proposed infiltration basin retains 0.8’ of water before it outlets to the city storm sewer. = 1.1" runoff x (1 ft/12") x 35,500 ) * = +,,-- ./+ Stormwater Narrative/Summary July 25, 2025 Central Automotive Parking Lot Addition Oak Park Heights, MN 4 | P a g e Table 3: Existing Stormwater Pond Summary (P-1) Storm Event Basin Inflow (CFS) Basin Outflow (CFS) Post Development HWL 2YR – 2.81” 2.68 0.08 901.44 10YR – 4.17” 4.40 0.67 901.71 100YR – 7.20” 8.58 2.85 902.37 Table 4: Proposed Expanded Stormwater Pond Summary (P-1) Storm Event Basin Inflow (CFS) Basin Outflow (CFS) Post Development HWL 2YR – 2.81” 4.04 0.19 901.51 10YR – 4.17” 6.35 1.00 901.82 100YR – 7.20” 11.80 3.17 902.50 The proposed provided water quality volume (WQV) is 4,380 cubic feet, which exceeds the required volume of 3,255 cubic feet. This WQV was calculated using the Stage-Area-Storage summary table from the submitted Post-Development HydroCAD model, based on the cumulative storage area below the pond’s Normal Water Level (NWL) elevation of 901.30 feet. Post-development discharge rates are less than or equal to the existing rates for each storm event, and the 100-year high water level has a minimum of 3 feet of freeboard before discharging to the 59th Street storm sewer, northwest of the proposed parking lot addition. With an assumed infiltration rate of 0.3 in/hr and a depth of 9.6 inches, we calculated a drawdown time of 32 hours. SHSAM Water Quality Analysis The SHSAM software was used to analysis the proposed parking lot addition’s improvements and correctly size the pretreatment structure and product device to achieve the proper water quality removal efficiencies for TSS. The proposed parking lot addition was modeled with runoff routed through the pretreatment structure before draining to the proposed infiltration basin. The results show a minimum 80% reduction of TSS was achieved for the proposed conditions. A summary of the results can be seen in Exhibit G. Summary The proposed site improvements and final grading is designed to utilize the existing terrain for drainage and minimizing post-development storm water runoff. Within the project boundary, some changes to the existing drainage patterns are expected due to the construction of the proposed parking lot addition, and other associated improvements. The project design does not propose to make major changes to drainage divides. PLOTTED:COMM. NO. DRAWING NO. ----18711 CENTRAL AUTOMOTIVE PARKING LOT ADDITION 14819 59TH ST N OAK PARK HEIGHTS, MINNESOTA 55082 1 3 6 0 5 1 s t A v e n u e N . #1 0 0 P l y m o u t h , M N 5 5 4 4 1 | a e -m n .c o m P 7 6 3 .4 1 2 .4 0 0 0 | F 7 6 3 .4 1 2 .4 0 9 0 A n d e r s o n E n g i n e e r i n g o f M i n n e s o t a , L L C DRAWING TITLE CHECKED BY:DRAWN:DESIGNED: DMMDMMDMM 7/25/2025 REVISION LOG DESCRIPTION OF REVISIONSNO.DATE CITY & MSCWMO SUBMITTAL 62823 DREW MESSMER, PEPRINT NAME: SIGNATURE: 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. DATE:LICENSE NO.7/25/2025 0 25' N EX. BUILDING (29 EX. STALLS PROV'D) EXISTING CONDITIONS MAP PRE 50' X1 P1 X2 X3 X4 PERVIOUS COVERAGE EXISTING DRAINAGE AREA #SUBCATCHMENT NAME PLOTTED:COMM. NO. DRAWING NO. ----18711 CENTRAL AUTOMOTIVE PARKING LOT ADDITION 14819 59TH ST N OAK PARK HEIGHTS, MINNESOTA 55082 1 3 6 0 5 1 s t A v e n u e N . #1 0 0 P l y m o u t h , M N 5 5 4 4 1 | a e -m n .c o m P 7 6 3 .4 1 2 .4 0 0 0 | F 7 6 3 .4 1 2 .4 0 9 0 A n d e r s o n E n g i n e e r i n g o f M i n n e s o t a , L L C DRAWING TITLE CHECKED BY:DRAWN:DESIGNED: DMMDMMDMM 7/25/2025 REVISION LOG DESCRIPTION OF REVISIONSNO.DATE CITY & MSCWMO SUBMITTAL 62823 DREW MESSMER, PEPRINT NAME: SIGNATURE: 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. DATE:LICENSE NO.7/25/2025 0 25' N EX. BUILDING (29 EX. STALLS PROV'D) 50' N1 P2 N2 N3 N4 PERVIOUS COVERAGE PROPOSED DRAINAGE AREA #SUBCATCHMENT NAME PROPOSED CONDITIONS MAP POST X1 EX. BLDG & LOT X2 EAST OF EX. POND X3 SOUTH OF EX. BLDG X4 N & W OF EX. LOT R1 OFFSITE - ROW R2 OFFSITE - EAST R3 OFFSITE - SOUTH P1 EX. POND Routing Diagram for 18711_PRE Prepared by Anderson Engineering Of MN, LLC, Printed 7/24/2025 HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Subcat Reach Pond Link 18711_Central Auto Parking Addition (PRE) 18711_PRE Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 2HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Area Listing (all nodes) Area (acres) CN Description (subcatchment-numbers) 1.970 61 >75% Grass cover, Good, HSG B (X1, X2, X3, X4) 0.536 98 Paved parking, HSG B (X1, X2, X4) 0.102 98 Water Surface, HSG B (X1) 2.608 70 TOTAL AREA 18711_Central Auto Parking Addition (PRE) MSE 24-hr 3 2-Year Rainfall=2.81"18711_PRE Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 3HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Time span=0.00-72.00 hrs, dt=0.01 hrs, 7201 points Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv. Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=40,941 sf 63.46% Impervious Runoff Depth=1.74"Subcatchment X1: EX. BLDG & LOT Tc=5.0 min CN=61/98 Runoff=2.68 cfs 0.137 af Runoff Area=51,826 sf 0.65% Impervious Runoff Depth=0.31"Subcatchment X2: EAST OF EX. POND Tc=10.0 min CN=61/98 Runoff=0.33 cfs 0.031 af Runoff Area=14,056 sf 0.00% Impervious Runoff Depth=0.30"Subcatchment X3: SOUTH OF EX. BLDG Tc=5.0 min CN=61/0 Runoff=0.12 cfs 0.008 af Runoff Area=6,782 sf 21.76% Impervious Runoff Depth=0.79"Subcatchment X4: N & W OF EX. LOT Tc=5.0 min CN=61/98 Runoff=0.19 cfs 0.010 af Inflow=0.19 cfs 0.032 afReach R1: OFFSITE - ROW Outflow=0.19 cfs 0.032 af Inflow=0.33 cfs 0.031 afReach R2: OFFSITE - EAST Outflow=0.33 cfs 0.031 af Inflow=0.12 cfs 0.008 afReach R3: OFFSITE - SOUTH Outflow=0.12 cfs 0.008 af Peak Elev=901.44' Storage=3,962 cf Inflow=2.68 cfs 0.137 afPond P1: EX. POND Discarded=0.03 cfs 0.115 af Primary=0.08 cfs 0.022 af Outflow=0.12 cfs 0.137 af Total Runoff Area = 2.608 ac Runoff Volume = 0.186 af Average Runoff Depth = 0.85" 75.53% Pervious = 1.970 ac 24.47% Impervious = 0.638 ac 18711_Central Auto Parking Addition (PRE) MSE 24-hr 3 2-Year Rainfall=2.81"18711_PRE Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 4HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Summary for Subcatchment X1: EX. BLDG & LOT Runoff = 2.68 cfs @ 12.12 hrs, Volume= 0.137 af, Depth= 1.74" Routed to Pond P1 : EX. POND Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.01 hrs MSE 24-hr 3 2-Year Rainfall=2.81" Area (sf) CN Description 14,959 61 >75% Grass cover, Good, HSG B 21,554 98 Paved parking, HSG B 4,428 98 Water Surface, HSG B 40,941 84 Weighted Average 14,959 61 36.54% Pervious Area 25,982 98 63.46% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment X1: EX. BLDG & LOT Runoff Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086420 Fl o w ( c f s ) 3 2 1 0 MSE 24-hr 3 2-Year Rainfall=2.81" Runoff Area=40,941 sf Runoff Volume=0.137 af Runoff Depth=1.74" Tc=5.0 min CN=61/98 2.68 cfs 18711_Central Auto Parking Addition (PRE) MSE 24-hr 3 2-Year Rainfall=2.81"18711_PRE Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 5HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Summary for Subcatchment X2: EAST OF EX. POND Runoff = 0.33 cfs @ 12.22 hrs, Volume= 0.031 af, Depth= 0.31" Routed to Reach R2 : OFFSITE - EAST Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.01 hrs MSE 24-hr 3 2-Year Rainfall=2.81" Area (sf) CN Description 51,490 61 >75% Grass cover, Good, HSG B 336 98 Paved parking, HSG B 51,826 61 Weighted Average 51,490 61 99.35% Pervious Area 336 98 0.65% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Subcatchment X2: EAST OF EX. POND Runoff Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086420 Fl o w ( c f s ) 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=2.81" Runoff Area=51,826 sf Runoff Volume=0.031 af Runoff Depth=0.31" Tc=10.0 min CN=61/98 0.33 cfs 18711_Central Auto Parking Addition (PRE) MSE 24-hr 3 2-Year Rainfall=2.81"18711_PRE Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 6HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Summary for Subcatchment X3: SOUTH OF EX. BLDG Runoff = 0.12 cfs @ 12.14 hrs, Volume= 0.008 af, Depth= 0.30" Routed to Reach R3 : OFFSITE - SOUTH Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.01 hrs MSE 24-hr 3 2-Year Rainfall=2.81" Area (sf) CN Description 14,056 61 >75% Grass cover, Good, HSG B 14,056 61 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment X3: SOUTH OF EX. BLDG Runoff Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086420 Fl o w ( c f s ) 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=2.81" Runoff Area=14,056 sf Runoff Volume=0.008 af Runoff Depth=0.30" Tc=5.0 min CN=61/0 0.12 cfs 18711_Central Auto Parking Addition (PRE) MSE 24-hr 3 2-Year Rainfall=2.81"18711_PRE Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 7HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Summary for Subcatchment X4: N & W OF EX. LOT Runoff = 0.19 cfs @ 12.13 hrs, Volume= 0.010 af, Depth= 0.79" Routed to Reach R1 : OFFSITE - ROW Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.01 hrs MSE 24-hr 3 2-Year Rainfall=2.81" Area (sf) CN Description 5,306 61 >75% Grass cover, Good, HSG B 1,476 98 Paved parking, HSG B 6,782 69 Weighted Average 5,306 61 78.24% Pervious Area 1,476 98 21.76% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment X4: N & W OF EX. LOT Runoff Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086420 Fl o w ( c f s ) 0.2 0.19 0.18 0.17 0.16 0.15 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 MSE 24-hr 3 2-Year Rainfall=2.81" Runoff Area=6,782 sf Runoff Volume=0.010 af Runoff Depth=0.79" Tc=5.0 min CN=61/98 0.19 cfs 18711_Central Auto Parking Addition (PRE) MSE 24-hr 3 2-Year Rainfall=2.81"18711_PRE Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 8HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Summary for Reach R1: OFFSITE - ROW Inflow Area = 1.096 ac, 57.54% Impervious, Inflow Depth = 0.35" for 2-Year event Inflow = 0.19 cfs @ 12.13 hrs, Volume= 0.032 af Outflow = 0.19 cfs @ 12.13 hrs, Volume= 0.032 af, Atten= 0%, Lag= 0.0 min Routed to nonexistent node 1R Routing by Stor-Ind+Trans method, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs Reach R1: OFFSITE - ROW Inflow Outflow Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086420 Fl o w ( c f s ) 0.2 0.19 0.18 0.17 0.16 0.15 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 Inflow Area=1.096 ac 0.19 cfs 0.19 cfs 18711_Central Auto Parking Addition (PRE) MSE 24-hr 3 2-Year Rainfall=2.81"18711_PRE Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 9HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Summary for Reach R2: OFFSITE - EAST Inflow Area = 1.190 ac, 0.65% Impervious, Inflow Depth = 0.31" for 2-Year event Inflow = 0.33 cfs @ 12.22 hrs, Volume= 0.031 af Outflow = 0.33 cfs @ 12.22 hrs, Volume= 0.031 af, Atten= 0%, Lag= 0.0 min Routed to nonexistent node 1R Routing by Stor-Ind+Trans method, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs Reach R2: OFFSITE - EAST Inflow Outflow Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086420 Fl o w ( c f s ) 0.36 0.34 0.32 0.3 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 Inflow Area=1.190 ac 0.33 cfs 0.33 cfs 18711_Central Auto Parking Addition (PRE) MSE 24-hr 3 2-Year Rainfall=2.81"18711_PRE Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 10HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Summary for Reach R3: OFFSITE - SOUTH Inflow Area = 0.323 ac, 0.00% Impervious, Inflow Depth = 0.30" for 2-Year event Inflow = 0.12 cfs @ 12.14 hrs, Volume= 0.008 af Outflow = 0.12 cfs @ 12.14 hrs, Volume= 0.008 af, Atten= 0%, Lag= 0.0 min Routed to nonexistent node 1R Routing by Stor-Ind+Trans method, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs Reach R3: OFFSITE - SOUTH Inflow Outflow Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086420 Fl o w ( c f s ) 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 Inflow Area=0.323 ac 0.12 cfs 0.12 cfs 18711_Central Auto Parking Addition (PRE) MSE 24-hr 3 2-Year Rainfall=2.81"18711_PRE Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 11HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Summary for Pond P1: EX. POND Inflow Area = 0.940 ac, 63.46% Impervious, Inflow Depth = 1.74" for 2-Year event Inflow = 2.68 cfs @ 12.12 hrs, Volume= 0.137 af Outflow = 0.12 cfs @ 13.50 hrs, Volume= 0.137 af, Atten= 96%, Lag= 82.5 min Discarded = 0.03 cfs @ 13.50 hrs, Volume= 0.115 af Primary = 0.08 cfs @ 13.50 hrs, Volume= 0.022 af Routed to Reach R1 : OFFSITE - ROW Routing by Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs Peak Elev= 901.44' @ 13.50 hrs Surf.Area= 4,536 sf Storage= 3,962 cf Flood Elev= 905.00' Surf.Area= 9,127 sf Storage= 26,512 cf Plug-Flow detention time= 933.4 min calculated for 0.137 af (100% of inflow) Center-of-Mass det. time= 933.7 min ( 1,694.8 - 761.1 ) Volume Invert Avail.Storage Storage Description #1 900.50' 26,512 cf Custom Stage Data (Irregular) Listed below (Recalc) Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area (feet) (sq-ft) (feet) (cubic-feet) (cubic-feet) (sq-ft) 900.50 4,000 220.0 0 0 4,000 901.00 4,200 242.0 2,050 2,050 4,817 902.00 4,987 261.0 4,588 6,638 5,618 903.00 5,837 282.0 5,406 12,044 6,565 904.00 7,018 317.0 6,418 18,463 8,260 905.00 9,127 430.0 8,049 26,512 14,988 Device Routing Invert Outlet Devices #1 Primary 899.50'12.0" Round Culvert L= 185.0' RCP, end-section conforming to fill, Ke= 0.500 Inlet / Outlet Invert= 899.50' / 897.70' S= 0.0097 '/' Cc= 0.900 n= 0.011 Concrete pipe, straight & clean, Flow Area= 0.79 sf #2 Device 1 901.30'12.0" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads #3 Discarded 900.50'0.300 in/hr Exfiltration over Surface area above 900.00' Excluded Surface area = 0 sf Discarded OutFlow Max=0.03 cfs @ 13.50 hrs HW=901.44' (Free Discharge) 3=Exfiltration (Exfiltration Controls 0.03 cfs) Primary OutFlow Max=0.08 cfs @ 13.50 hrs HW=901.44' (Free Discharge) 1=Culvert (Passes 0.08 cfs of 4.38 cfs potential flow) 2=Orifice/Grate (Orifice Controls 0.08 cfs @ 1.26 fps) 18711_Central Auto Parking Addition (PRE) MSE 24-hr 3 2-Year Rainfall=2.81"18711_PRE Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 12HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Pond P1: EX. POND Inflow Outflow Discarded Primary Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086420 Fl o w ( c f s ) 3 2 1 0 Inflow Area=0.940 ac Peak Elev=901.44' Storage=3,962 cf 2.68 cfs 0.12 cfs 0.03 cfs 0.08 cfs 18711_Central Auto Parking Addition (PRE) MSE 24-hr 3 2-Year Rainfall=2.81"18711_PRE Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 13HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Stage-Area-Storage for Pond P1: EX. POND Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 900.50 4,000 0 900.55 4,020 200 900.60 4,040 402 900.65 4,059 604 900.70 4,079 808 900.75 4,099 1,012 900.80 4,119 1,218 900.85 4,139 1,424 900.90 4,160 1,632 900.95 4,180 1,840 901.00 4,200 2,050 901.05 4,238 2,261 901.10 4,276 2,474 901.15 4,314 2,688 901.20 4,352 2,905 901.25 4,390 3,124 901.30 4,429 3,344 901.35 4,468 3,566 901.40 4,507 3,791 901.45 4,546 4,017 901.50 4,585 4,245 901.55 4,624 4,476 901.60 4,664 4,708 901.65 4,704 4,942 901.70 4,744 5,178 901.75 4,784 5,416 901.80 4,824 5,657 901.85 4,865 5,899 901.90 4,905 6,143 901.95 4,946 6,389 902.00 4,987 6,638 902.05 5,028 6,888 902.10 5,069 7,140 902.15 5,110 7,395 902.20 5,152 7,651 902.25 5,193 7,910 902.30 5,235 8,171 902.35 5,277 8,434 902.40 5,319 8,699 902.45 5,361 8,966 902.50 5,404 9,235 902.55 5,446 9,506 902.60 5,489 9,779 902.65 5,532 10,055 902.70 5,575 10,332 902.75 5,618 10,612 902.80 5,662 10,894 902.85 5,705 11,178 902.90 5,749 11,465 902.95 5,793 11,753 903.00 5,837 12,044 Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 903.05 5,893 12,337 903.10 5,950 12,633 903.15 6,007 12,932 903.20 6,065 13,234 903.25 6,122 13,539 903.30 6,180 13,846 903.35 6,238 14,157 903.40 6,296 14,470 903.45 6,355 14,786 903.50 6,414 15,106 903.55 6,473 15,428 903.60 6,533 15,753 903.65 6,592 16,081 903.70 6,652 16,412 903.75 6,713 16,746 903.80 6,773 17,083 903.85 6,834 17,424 903.90 6,895 17,767 903.95 6,956 18,113 904.00 7,018 18,463 904.05 7,117 18,816 904.10 7,216 19,174 904.15 7,317 19,538 904.20 7,418 19,906 904.25 7,519 20,279 904.30 7,622 20,658 904.35 7,725 21,042 904.40 7,828 21,430 904.45 7,933 21,824 904.50 8,038 22,224 904.55 8,144 22,628 904.60 8,250 23,038 904.65 8,357 23,453 904.70 8,465 23,874 904.75 8,574 24,300 904.80 8,683 24,731 904.85 8,793 25,168 904.90 8,904 25,610 904.95 9,015 26,058 905.00 9,127 26,512 18711_Central Auto Parking Addition (PRE) MSE 24-hr 3 10-Year Rainfall=4.17"18711_PRE Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 14HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Time span=0.00-72.00 hrs, dt=0.01 hrs, 7201 points Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv. Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=40,941 sf 63.46% Impervious Runoff Depth=2.83"Subcatchment X1: EX. BLDG & LOT Tc=5.0 min CN=61/98 Runoff=4.40 cfs 0.221 af Runoff Area=51,826 sf 0.65% Impervious Runoff Depth=0.92"Subcatchment X2: EAST OF EX. POND Tc=10.0 min CN=61/98 Runoff=1.51 cfs 0.091 af Runoff Area=14,056 sf 0.00% Impervious Runoff Depth=0.90"Subcatchment X3: SOUTH OF EX. BLDG Tc=5.0 min CN=61/0 Runoff=0.53 cfs 0.024 af Runoff Area=6,782 sf 21.76% Impervious Runoff Depth=1.56"Subcatchment X4: N & W OF EX. LOT Tc=5.0 min CN=61/98 Runoff=0.42 cfs 0.020 af Inflow=0.76 cfs 0.119 afReach R1: OFFSITE - ROW Outflow=0.76 cfs 0.119 af Inflow=1.51 cfs 0.091 afReach R2: OFFSITE - EAST Outflow=1.51 cfs 0.091 af Inflow=0.53 cfs 0.024 afReach R3: OFFSITE - SOUTH Outflow=0.53 cfs 0.024 af Peak Elev=901.71' Storage=5,244 cf Inflow=4.40 cfs 0.221 afPond P1: EX. POND Discarded=0.03 cfs 0.123 af Primary=0.67 cfs 0.099 af Outflow=0.71 cfs 0.221 af Total Runoff Area = 2.608 ac Runoff Volume = 0.357 af Average Runoff Depth = 1.64" 75.53% Pervious = 1.970 ac 24.47% Impervious = 0.638 ac 18711_Central Auto Parking Addition (PRE) MSE 24-hr 3 10-Year Rainfall=4.17"18711_PRE Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 15HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Summary for Subcatchment X1: EX. BLDG & LOT Runoff = 4.40 cfs @ 12.12 hrs, Volume= 0.221 af, Depth= 2.83" Routed to Pond P1 : EX. POND Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.01 hrs MSE 24-hr 3 10-Year Rainfall=4.17" Area (sf) CN Description 14,959 61 >75% Grass cover, Good, HSG B 21,554 98 Paved parking, HSG B 4,428 98 Water Surface, HSG B 40,941 84 Weighted Average 14,959 61 36.54% Pervious Area 25,982 98 63.46% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment X1: EX. BLDG & LOT Runoff Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086420 Fl o w ( c f s ) 4 3 2 1 0 MSE 24-hr 3 10-Year Rainfall=4.17" Runoff Area=40,941 sf Runoff Volume=0.221 af Runoff Depth=2.83" Tc=5.0 min CN=61/98 4.40 cfs 18711_Central Auto Parking Addition (PRE) MSE 24-hr 3 10-Year Rainfall=4.17"18711_PRE Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 16HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Summary for Subcatchment X2: EAST OF EX. POND Runoff = 1.51 cfs @ 12.19 hrs, Volume= 0.091 af, Depth= 0.92" Routed to Reach R2 : OFFSITE - EAST Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.01 hrs MSE 24-hr 3 10-Year Rainfall=4.17" Area (sf) CN Description 51,490 61 >75% Grass cover, Good, HSG B 336 98 Paved parking, HSG B 51,826 61 Weighted Average 51,490 61 99.35% Pervious Area 336 98 0.65% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Subcatchment X2: EAST OF EX. POND Runoff Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086420 Fl o w ( c f s ) 1 0 MSE 24-hr 3 10-Year Rainfall=4.17" Runoff Area=51,826 sf Runoff Volume=0.091 af Runoff Depth=0.92" Tc=10.0 min CN=61/98 1.51 cfs 18711_Central Auto Parking Addition (PRE) MSE 24-hr 3 10-Year Rainfall=4.17"18711_PRE Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 17HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Summary for Subcatchment X3: SOUTH OF EX. BLDG Runoff = 0.53 cfs @ 12.13 hrs, Volume= 0.024 af, Depth= 0.90" Routed to Reach R3 : OFFSITE - SOUTH Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.01 hrs MSE 24-hr 3 10-Year Rainfall=4.17" Area (sf) CN Description 14,056 61 >75% Grass cover, Good, HSG B 14,056 61 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment X3: SOUTH OF EX. BLDG Runoff Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086420 Fl o w ( c f s ) 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=4.17" Runoff Area=14,056 sf Runoff Volume=0.024 af Runoff Depth=0.90" Tc=5.0 min CN=61/0 0.53 cfs 18711_Central Auto Parking Addition (PRE) MSE 24-hr 3 10-Year Rainfall=4.17"18711_PRE Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 18HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Summary for Subcatchment X4: N & W OF EX. LOT Runoff = 0.42 cfs @ 12.13 hrs, Volume= 0.020 af, Depth= 1.56" Routed to Reach R1 : OFFSITE - ROW Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.01 hrs MSE 24-hr 3 10-Year Rainfall=4.17" Area (sf) CN Description 5,306 61 >75% Grass cover, Good, HSG B 1,476 98 Paved parking, HSG B 6,782 69 Weighted Average 5,306 61 78.24% Pervious Area 1,476 98 21.76% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment X4: N & W OF EX. LOT Runoff Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086420 Fl o w ( c f s ) 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 10-Year Rainfall=4.17" Runoff Area=6,782 sf Runoff Volume=0.020 af Runoff Depth=1.56" Tc=5.0 min CN=61/98 0.42 cfs 18711_Central Auto Parking Addition (PRE) MSE 24-hr 3 10-Year Rainfall=4.17"18711_PRE Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 19HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Summary for Reach R1: OFFSITE - ROW Inflow Area = 1.096 ac, 57.54% Impervious, Inflow Depth = 1.30" for 10-Year event Inflow = 0.76 cfs @ 12.42 hrs, Volume= 0.119 af Outflow = 0.76 cfs @ 12.42 hrs, Volume= 0.119 af, Atten= 0%, Lag= 0.0 min Routed to nonexistent node 1R Routing by Stor-Ind+Trans method, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs Reach R1: OFFSITE - ROW Inflow Outflow Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086420 Fl o w ( c f s ) 0.8 0.75 0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Inflow Area=1.096 ac 0.76 cfs 0.76 cfs 18711_Central Auto Parking Addition (PRE) MSE 24-hr 3 10-Year Rainfall=4.17"18711_PRE Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 20HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Summary for Reach R2: OFFSITE - EAST Inflow Area = 1.190 ac, 0.65% Impervious, Inflow Depth = 0.92" for 10-Year event Inflow = 1.51 cfs @ 12.19 hrs, Volume= 0.091 af Outflow = 1.51 cfs @ 12.19 hrs, Volume= 0.091 af, Atten= 0%, Lag= 0.0 min Routed to nonexistent node 1R Routing by Stor-Ind+Trans method, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs Reach R2: OFFSITE - EAST Inflow Outflow Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086420 Fl o w ( c f s ) 1 0 Inflow Area=1.190 ac 1.51 cfs 1.51 cfs 18711_Central Auto Parking Addition (PRE) MSE 24-hr 3 10-Year Rainfall=4.17"18711_PRE Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 21HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Summary for Reach R3: OFFSITE - SOUTH Inflow Area = 0.323 ac, 0.00% Impervious, Inflow Depth = 0.90" for 10-Year event Inflow = 0.53 cfs @ 12.13 hrs, Volume= 0.024 af Outflow = 0.53 cfs @ 12.13 hrs, Volume= 0.024 af, Atten= 0%, Lag= 0.0 min Routed to nonexistent node 1R Routing by Stor-Ind+Trans method, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs Reach R3: OFFSITE - SOUTH Inflow Outflow Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086420 Fl o w ( c f s ) 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=0.323 ac 0.53 cfs 0.53 cfs 18711_Central Auto Parking Addition (PRE) MSE 24-hr 3 10-Year Rainfall=4.17"18711_PRE Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 22HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Summary for Pond P1: EX. POND Inflow Area = 0.940 ac, 63.46% Impervious, Inflow Depth = 2.83" for 10-Year event Inflow = 4.40 cfs @ 12.12 hrs, Volume= 0.221 af Outflow = 0.71 cfs @ 12.45 hrs, Volume= 0.221 af, Atten= 84%, Lag= 19.8 min Discarded = 0.03 cfs @ 12.45 hrs, Volume= 0.123 af Primary = 0.67 cfs @ 12.45 hrs, Volume= 0.099 af Routed to Reach R1 : OFFSITE - ROW Routing by Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs Peak Elev= 901.71' @ 12.45 hrs Surf.Area= 4,755 sf Storage= 5,244 cf Flood Elev= 905.00' Surf.Area= 9,127 sf Storage= 26,512 cf Plug-Flow detention time= 638.1 min calculated for 0.221 af (100% of inflow) Center-of-Mass det. time= 638.1 min ( 1,396.4 - 758.4 ) Volume Invert Avail.Storage Storage Description #1 900.50' 26,512 cf Custom Stage Data (Irregular) Listed below (Recalc) Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area (feet) (sq-ft) (feet) (cubic-feet) (cubic-feet) (sq-ft) 900.50 4,000 220.0 0 0 4,000 901.00 4,200 242.0 2,050 2,050 4,817 902.00 4,987 261.0 4,588 6,638 5,618 903.00 5,837 282.0 5,406 12,044 6,565 904.00 7,018 317.0 6,418 18,463 8,260 905.00 9,127 430.0 8,049 26,512 14,988 Device Routing Invert Outlet Devices #1 Primary 899.50'12.0" Round Culvert L= 185.0' RCP, end-section conforming to fill, Ke= 0.500 Inlet / Outlet Invert= 899.50' / 897.70' S= 0.0097 '/' Cc= 0.900 n= 0.011 Concrete pipe, straight & clean, Flow Area= 0.79 sf #2 Device 1 901.30'12.0" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads #3 Discarded 900.50'0.300 in/hr Exfiltration over Surface area above 900.00' Excluded Surface area = 0 sf Discarded OutFlow Max=0.03 cfs @ 12.45 hrs HW=901.71' (Free Discharge) 3=Exfiltration (Exfiltration Controls 0.03 cfs) Primary OutFlow Max=0.67 cfs @ 12.45 hrs HW=901.71' (Free Discharge) 1=Culvert (Passes 0.67 cfs of 4.60 cfs potential flow) 2=Orifice/Grate (Orifice Controls 0.67 cfs @ 2.19 fps) 18711_Central Auto Parking Addition (PRE) MSE 24-hr 3 10-Year Rainfall=4.17"18711_PRE Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 23HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Pond P1: EX. POND Inflow Outflow Discarded Primary Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086420 Fl o w ( c f s ) 4 3 2 1 0 Inflow Area=0.940 ac Peak Elev=901.71' Storage=5,244 cf 4.40 cfs 0.71 cfs 0.03 cfs 0.67 cfs 18711_Central Auto Parking Addition (PRE) MSE 24-hr 3 10-Year Rainfall=4.17"18711_PRE Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 24HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Stage-Area-Storage for Pond P1: EX. POND Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 900.50 4,000 0 900.55 4,020 200 900.60 4,040 402 900.65 4,059 604 900.70 4,079 808 900.75 4,099 1,012 900.80 4,119 1,218 900.85 4,139 1,424 900.90 4,160 1,632 900.95 4,180 1,840 901.00 4,200 2,050 901.05 4,238 2,261 901.10 4,276 2,474 901.15 4,314 2,688 901.20 4,352 2,905 901.25 4,390 3,124 901.30 4,429 3,344 901.35 4,468 3,566 901.40 4,507 3,791 901.45 4,546 4,017 901.50 4,585 4,245 901.55 4,624 4,476 901.60 4,664 4,708 901.65 4,704 4,942 901.70 4,744 5,178 901.75 4,784 5,416 901.80 4,824 5,657 901.85 4,865 5,899 901.90 4,905 6,143 901.95 4,946 6,389 902.00 4,987 6,638 902.05 5,028 6,888 902.10 5,069 7,140 902.15 5,110 7,395 902.20 5,152 7,651 902.25 5,193 7,910 902.30 5,235 8,171 902.35 5,277 8,434 902.40 5,319 8,699 902.45 5,361 8,966 902.50 5,404 9,235 902.55 5,446 9,506 902.60 5,489 9,779 902.65 5,532 10,055 902.70 5,575 10,332 902.75 5,618 10,612 902.80 5,662 10,894 902.85 5,705 11,178 902.90 5,749 11,465 902.95 5,793 11,753 903.00 5,837 12,044 Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 903.05 5,893 12,337 903.10 5,950 12,633 903.15 6,007 12,932 903.20 6,065 13,234 903.25 6,122 13,539 903.30 6,180 13,846 903.35 6,238 14,157 903.40 6,296 14,470 903.45 6,355 14,786 903.50 6,414 15,106 903.55 6,473 15,428 903.60 6,533 15,753 903.65 6,592 16,081 903.70 6,652 16,412 903.75 6,713 16,746 903.80 6,773 17,083 903.85 6,834 17,424 903.90 6,895 17,767 903.95 6,956 18,113 904.00 7,018 18,463 904.05 7,117 18,816 904.10 7,216 19,174 904.15 7,317 19,538 904.20 7,418 19,906 904.25 7,519 20,279 904.30 7,622 20,658 904.35 7,725 21,042 904.40 7,828 21,430 904.45 7,933 21,824 904.50 8,038 22,224 904.55 8,144 22,628 904.60 8,250 23,038 904.65 8,357 23,453 904.70 8,465 23,874 904.75 8,574 24,300 904.80 8,683 24,731 904.85 8,793 25,168 904.90 8,904 25,610 904.95 9,015 26,058 905.00 9,127 26,512 18711_Central Auto Parking Addition (PRE) MSE 24-hr 3 100-Year Rainfall=7.20"18711_PRE Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 25HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Time span=0.00-72.00 hrs, dt=0.01 hrs, 7201 points Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv. Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=40,941 sf 63.46% Impervious Runoff Depth=5.46"Subcatchment X1: EX. BLDG & LOT Tc=5.0 min CN=61/98 Runoff=8.58 cfs 0.427 af Runoff Area=51,826 sf 0.65% Impervious Runoff Depth=2.87"Subcatchment X2: EAST OF EX. POND Tc=10.0 min CN=61/98 Runoff=5.27 cfs 0.285 af Runoff Area=14,056 sf 0.00% Impervious Runoff Depth=2.85"Subcatchment X3: SOUTH OF EX. BLDG Tc=5.0 min CN=61/0 Runoff=1.81 cfs 0.077 af Runoff Area=6,782 sf 21.76% Impervious Runoff Depth=3.74"Subcatchment X4: N & W OF EX. LOT Tc=5.0 min CN=61/98 Runoff=1.06 cfs 0.049 af Inflow=3.50 cfs 0.345 afReach R1: OFFSITE - ROW Outflow=3.50 cfs 0.345 af Inflow=5.27 cfs 0.285 afReach R2: OFFSITE - EAST Outflow=5.27 cfs 0.285 af Inflow=1.81 cfs 0.077 afReach R3: OFFSITE - SOUTH Outflow=1.81 cfs 0.077 af Peak Elev=902.37' Storage=8,531 cf Inflow=8.58 cfs 0.427 afPond P1: EX. POND Discarded=0.04 cfs 0.131 af Primary=2.85 cfs 0.296 af Outflow=2.89 cfs 0.427 af Total Runoff Area = 2.608 ac Runoff Volume = 0.838 af Average Runoff Depth = 3.85" 75.53% Pervious = 1.970 ac 24.47% Impervious = 0.638 ac 18711_Central Auto Parking Addition (PRE) MSE 24-hr 3 100-Year Rainfall=7.20"18711_PRE Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 26HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Summary for Subcatchment X1: EX. BLDG & LOT Runoff = 8.58 cfs @ 12.12 hrs, Volume= 0.427 af, Depth= 5.46" Routed to Pond P1 : EX. POND Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.01 hrs MSE 24-hr 3 100-Year Rainfall=7.20" Area (sf) CN Description 14,959 61 >75% Grass cover, Good, HSG B 21,554 98 Paved parking, HSG B 4,428 98 Water Surface, HSG B 40,941 84 Weighted Average 14,959 61 36.54% Pervious Area 25,982 98 63.46% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment X1: EX. BLDG & LOT Runoff Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086420 Fl o w ( c f s ) 9 8 7 6 5 4 3 2 1 0 MSE 24-hr 3 100-Year Rainfall=7.20" Runoff Area=40,941 sf Runoff Volume=0.427 af Runoff Depth=5.46" Tc=5.0 min CN=61/98 8.58 cfs 18711_Central Auto Parking Addition (PRE) MSE 24-hr 3 100-Year Rainfall=7.20"18711_PRE Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 27HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Summary for Subcatchment X2: EAST OF EX. POND Runoff = 5.27 cfs @ 12.18 hrs, Volume= 0.285 af, Depth= 2.87" Routed to Reach R2 : OFFSITE - EAST Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.01 hrs MSE 24-hr 3 100-Year Rainfall=7.20" Area (sf) CN Description 51,490 61 >75% Grass cover, Good, HSG B 336 98 Paved parking, HSG B 51,826 61 Weighted Average 51,490 61 99.35% Pervious Area 336 98 0.65% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Subcatchment X2: EAST OF EX. POND Runoff Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086420 Fl o w ( c f s ) 5 4 3 2 1 0 MSE 24-hr 3 100-Year Rainfall=7.20" Runoff Area=51,826 sf Runoff Volume=0.285 af Runoff Depth=2.87" Tc=10.0 min CN=61/98 5.27 cfs 18711_Central Auto Parking Addition (PRE) MSE 24-hr 3 100-Year Rainfall=7.20"18711_PRE Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 28HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Summary for Subcatchment X3: SOUTH OF EX. BLDG Runoff = 1.81 cfs @ 12.13 hrs, Volume= 0.077 af, Depth= 2.85" Routed to Reach R3 : OFFSITE - SOUTH Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.01 hrs MSE 24-hr 3 100-Year Rainfall=7.20" Area (sf) CN Description 14,056 61 >75% Grass cover, Good, HSG B 14,056 61 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment X3: SOUTH OF EX. BLDG Runoff Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086420 Fl o w ( c f s ) 2 1 0 MSE 24-hr 3 100-Year Rainfall=7.20" Runoff Area=14,056 sf Runoff Volume=0.077 af Runoff Depth=2.85" Tc=5.0 min CN=61/0 1.81 cfs 18711_Central Auto Parking Addition (PRE) MSE 24-hr 3 100-Year Rainfall=7.20"18711_PRE Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 29HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Summary for Subcatchment X4: N & W OF EX. LOT Runoff = 1.06 cfs @ 12.13 hrs, Volume= 0.049 af, Depth= 3.74" Routed to Reach R1 : OFFSITE - ROW Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.01 hrs MSE 24-hr 3 100-Year Rainfall=7.20" Area (sf) CN Description 5,306 61 >75% Grass cover, Good, HSG B 1,476 98 Paved parking, HSG B 6,782 69 Weighted Average 5,306 61 78.24% Pervious Area 1,476 98 21.76% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment X4: N & W OF EX. LOT Runoff Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086420 Fl o w ( c f s ) 1 0 MSE 24-hr 3 100-Year Rainfall=7.20" Runoff Area=6,782 sf Runoff Volume=0.049 af Runoff Depth=3.74" Tc=5.0 min CN=61/98 1.06 cfs 18711_Central Auto Parking Addition (PRE) MSE 24-hr 3 100-Year Rainfall=7.20"18711_PRE Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 30HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Summary for Reach R1: OFFSITE - ROW Inflow Area = 1.096 ac, 57.54% Impervious, Inflow Depth = 3.78" for 100-Year event Inflow = 3.50 cfs @ 12.15 hrs, Volume= 0.345 af Outflow = 3.50 cfs @ 12.15 hrs, Volume= 0.345 af, Atten= 0%, Lag= 0.0 min Routed to nonexistent node 1R Routing by Stor-Ind+Trans method, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs Reach R1: OFFSITE - ROW Inflow Outflow Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086420 Fl o w ( c f s ) 3 2 1 0 Inflow Area=1.096 ac 3.50 cfs 3.50 cfs 18711_Central Auto Parking Addition (PRE) MSE 24-hr 3 100-Year Rainfall=7.20"18711_PRE Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 31HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Summary for Reach R2: OFFSITE - EAST Inflow Area = 1.190 ac, 0.65% Impervious, Inflow Depth = 2.87" for 100-Year event Inflow = 5.27 cfs @ 12.18 hrs, Volume= 0.285 af Outflow = 5.27 cfs @ 12.18 hrs, Volume= 0.285 af, Atten= 0%, Lag= 0.0 min Routed to nonexistent node 1R Routing by Stor-Ind+Trans method, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs Reach R2: OFFSITE - EAST Inflow Outflow Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086420 Fl o w ( c f s ) 5 4 3 2 1 0 Inflow Area=1.190 ac 5.27 cfs 5.27 cfs 18711_Central Auto Parking Addition (PRE) MSE 24-hr 3 100-Year Rainfall=7.20"18711_PRE Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 32HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Summary for Reach R3: OFFSITE - SOUTH Inflow Area = 0.323 ac, 0.00% Impervious, Inflow Depth = 2.85" for 100-Year event Inflow = 1.81 cfs @ 12.13 hrs, Volume= 0.077 af Outflow = 1.81 cfs @ 12.13 hrs, Volume= 0.077 af, Atten= 0%, Lag= 0.0 min Routed to nonexistent node 1R Routing by Stor-Ind+Trans method, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs Reach R3: OFFSITE - SOUTH Inflow Outflow Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086420 Fl o w ( c f s ) 2 1 0 Inflow Area=0.323 ac 1.81 cfs 1.81 cfs 18711_Central Auto Parking Addition (PRE) MSE 24-hr 3 100-Year Rainfall=7.20"18711_PRE Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 33HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Summary for Pond P1: EX. POND Inflow Area = 0.940 ac, 63.46% Impervious, Inflow Depth = 5.46" for 100-Year event Inflow = 8.58 cfs @ 12.12 hrs, Volume= 0.427 af Outflow = 2.89 cfs @ 12.25 hrs, Volume= 0.427 af, Atten= 66%, Lag= 7.7 min Discarded = 0.04 cfs @ 12.25 hrs, Volume= 0.131 af Primary = 2.85 cfs @ 12.25 hrs, Volume= 0.296 af Routed to Reach R1 : OFFSITE - ROW Routing by Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs Peak Elev= 902.37' @ 12.25 hrs Surf.Area= 5,292 sf Storage= 8,531 cf Flood Elev= 905.00' Surf.Area= 9,127 sf Storage= 26,512 cf Plug-Flow detention time= 375.0 min calculated for 0.427 af (100% of inflow) Center-of-Mass det. time= 374.9 min ( 1,129.7 - 754.8 ) Volume Invert Avail.Storage Storage Description #1 900.50' 26,512 cf Custom Stage Data (Irregular) Listed below (Recalc) Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area (feet) (sq-ft) (feet) (cubic-feet) (cubic-feet) (sq-ft) 900.50 4,000 220.0 0 0 4,000 901.00 4,200 242.0 2,050 2,050 4,817 902.00 4,987 261.0 4,588 6,638 5,618 903.00 5,837 282.0 5,406 12,044 6,565 904.00 7,018 317.0 6,418 18,463 8,260 905.00 9,127 430.0 8,049 26,512 14,988 Device Routing Invert Outlet Devices #1 Primary 899.50'12.0" Round Culvert L= 185.0' RCP, end-section conforming to fill, Ke= 0.500 Inlet / Outlet Invert= 899.50' / 897.70' S= 0.0097 '/' Cc= 0.900 n= 0.011 Concrete pipe, straight & clean, Flow Area= 0.79 sf #2 Device 1 901.30'12.0" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads #3 Discarded 900.50'0.300 in/hr Exfiltration over Surface area above 900.00' Excluded Surface area = 0 sf Discarded OutFlow Max=0.04 cfs @ 12.25 hrs HW=902.37' (Free Discharge) 3=Exfiltration (Exfiltration Controls 0.04 cfs) Primary OutFlow Max=2.85 cfs @ 12.25 hrs HW=902.37' (Free Discharge) 1=Culvert (Passes 2.85 cfs of 5.07 cfs potential flow) 2=Orifice/Grate (Orifice Controls 2.85 cfs @ 3.63 fps) 18711_Central Auto Parking Addition (PRE) MSE 24-hr 3 100-Year Rainfall=7.20"18711_PRE Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 34HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Pond P1: EX. POND Inflow Outflow Discarded Primary Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086420 Fl o w ( c f s ) 9 8 7 6 5 4 3 2 1 0 Inflow Area=0.940 ac Peak Elev=902.37' Storage=8,531 cf 8.58 cfs 2.89 cfs 0.04 cfs 2.85 cfs 18711_Central Auto Parking Addition (PRE) MSE 24-hr 3 100-Year Rainfall=7.20"18711_PRE Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 35HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Stage-Area-Storage for Pond P1: EX. POND Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 900.50 4,000 0 900.55 4,020 200 900.60 4,040 402 900.65 4,059 604 900.70 4,079 808 900.75 4,099 1,012 900.80 4,119 1,218 900.85 4,139 1,424 900.90 4,160 1,632 900.95 4,180 1,840 901.00 4,200 2,050 901.05 4,238 2,261 901.10 4,276 2,474 901.15 4,314 2,688 901.20 4,352 2,905 901.25 4,390 3,124 901.30 4,429 3,344 901.35 4,468 3,566 901.40 4,507 3,791 901.45 4,546 4,017 901.50 4,585 4,245 901.55 4,624 4,476 901.60 4,664 4,708 901.65 4,704 4,942 901.70 4,744 5,178 901.75 4,784 5,416 901.80 4,824 5,657 901.85 4,865 5,899 901.90 4,905 6,143 901.95 4,946 6,389 902.00 4,987 6,638 902.05 5,028 6,888 902.10 5,069 7,140 902.15 5,110 7,395 902.20 5,152 7,651 902.25 5,193 7,910 902.30 5,235 8,171 902.35 5,277 8,434 902.40 5,319 8,699 902.45 5,361 8,966 902.50 5,404 9,235 902.55 5,446 9,506 902.60 5,489 9,779 902.65 5,532 10,055 902.70 5,575 10,332 902.75 5,618 10,612 902.80 5,662 10,894 902.85 5,705 11,178 902.90 5,749 11,465 902.95 5,793 11,753 903.00 5,837 12,044 Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 903.05 5,893 12,337 903.10 5,950 12,633 903.15 6,007 12,932 903.20 6,065 13,234 903.25 6,122 13,539 903.30 6,180 13,846 903.35 6,238 14,157 903.40 6,296 14,470 903.45 6,355 14,786 903.50 6,414 15,106 903.55 6,473 15,428 903.60 6,533 15,753 903.65 6,592 16,081 903.70 6,652 16,412 903.75 6,713 16,746 903.80 6,773 17,083 903.85 6,834 17,424 903.90 6,895 17,767 903.95 6,956 18,113 904.00 7,018 18,463 904.05 7,117 18,816 904.10 7,216 19,174 904.15 7,317 19,538 904.20 7,418 19,906 904.25 7,519 20,279 904.30 7,622 20,658 904.35 7,725 21,042 904.40 7,828 21,430 904.45 7,933 21,824 904.50 8,038 22,224 904.55 8,144 22,628 904.60 8,250 23,038 904.65 8,357 23,453 904.70 8,465 23,874 904.75 8,574 24,300 904.80 8,683 24,731 904.85 8,793 25,168 904.90 8,904 25,610 904.95 9,015 26,058 905.00 9,127 26,512 N1 EX. BLDG & NEW LOT N2 EAST OF EX. POND N3 SOUTH OF EX. BLDG N4 N & W OF EX. LOT R1 OFFSITE - ROW R2 OFFSITE - EAST R3 OFFSITE - SOUTH P2 EXPANDED POND Routing Diagram for 18711_POST Prepared by Anderson Engineering Of MN, LLC, Printed 7/24/2025 HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Subcat Reach Pond Link 18711_Central Auto Parking Addition (POST) 18711_POST Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 2HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Area Listing (all nodes) Area (acres) CN Description (subcatchment-numbers) 1.647 61 >75% Grass cover, Good, HSG B (N1, N2, N3, N4) 0.814 98 Paved parking, HSG B (N1, N2, N4) 0.147 98 Water Surface, HSG B (N1) 2.608 75 TOTAL AREA 18711_Central Auto Parking Addition (POST) MSE 24-hr 3 2-Year Rainfall=2.81"18711_POST Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 3HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Time span=0.00-72.00 hrs, dt=0.01 hrs, 7201 points Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv. Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=52,186 sf 76.43% Impervious Runoff Depth=2.04"Subcatchment N1: EX. BLDG & NEW LOT Tc=5.0 min CN=61/98 Runoff=4.04 cfs 0.204 af Runoff Area=40,662 sf 0.83% Impervious Runoff Depth=0.31"Subcatchment N2: EAST OF EX. POND Tc=10.0 min CN=61/98 Runoff=0.27 cfs 0.024 af Runoff Area=13,806 sf 0.00% Impervious Runoff Depth=0.30"Subcatchment N3: SOUTH OF EX. BLDG Tc=5.0 min CN=61/0 Runoff=0.12 cfs 0.008 af Runoff Area=6,951 sf 23.45% Impervious Runoff Depth=0.83"Subcatchment N4: N & W OF EX. LOT Tc=5.0 min CN=61/98 Runoff=0.20 cfs 0.011 af Inflow=0.20 cfs 0.059 afReach R1: OFFSITE - ROW Outflow=0.20 cfs 0.059 af Inflow=0.27 cfs 0.024 afReach R2: OFFSITE - EAST Outflow=0.27 cfs 0.024 af Inflow=0.12 cfs 0.008 afReach R3: OFFSITE - SOUTH Outflow=0.12 cfs 0.008 af Peak Elev=901.51' Storage=5,735 cf Inflow=4.04 cfs 0.204 afPond P2: EXPANDED POND Discarded=0.05 cfs 0.156 af Primary=0.19 cfs 0.048 af Outflow=0.23 cfs 0.204 af Total Runoff Area = 2.608 ac Runoff Volume = 0.247 af Average Runoff Depth = 1.14" 63.16% Pervious = 1.647 ac 36.84% Impervious = 0.961 ac 18711_Central Auto Parking Addition (POST) MSE 24-hr 3 2-Year Rainfall=2.81"18711_POST Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 4HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Summary for Subcatchment N1: EX. BLDG & NEW LOT Runoff = 4.04 cfs @ 12.12 hrs, Volume= 0.204 af, Depth= 2.04" Routed to Pond P2 : EXPANDED POND Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.01 hrs MSE 24-hr 3 2-Year Rainfall=2.81" Area (sf) CN Description 12,302 61 >75% Grass cover, Good, HSG B 33,473 98 Paved parking, HSG B 6,411 98 Water Surface, HSG B 52,186 89 Weighted Average 12,302 61 23.57% Pervious Area 39,884 98 76.43% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment N1: EX. BLDG & NEW LOT Runoff Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086420 Fl o w ( c f s ) 4 3 2 1 0 MSE 24-hr 3 2-Year Rainfall=2.81" Runoff Area=52,186 sf Runoff Volume=0.204 af Runoff Depth=2.04" Tc=5.0 min CN=61/98 4.04 cfs 18711_Central Auto Parking Addition (POST) MSE 24-hr 3 2-Year Rainfall=2.81"18711_POST Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 5HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Summary for Subcatchment N2: EAST OF EX. POND Runoff = 0.27 cfs @ 12.22 hrs, Volume= 0.024 af, Depth= 0.31" Routed to Reach R2 : OFFSITE - EAST Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.01 hrs MSE 24-hr 3 2-Year Rainfall=2.81" Area (sf) CN Description 40,326 61 >75% Grass cover, Good, HSG B 336 98 Paved parking, HSG B 40,662 61 Weighted Average 40,326 61 99.17% Pervious Area 336 98 0.83% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Subcatchment N2: EAST OF EX. POND Runoff Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086420 Fl o w ( c f s ) 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=2.81" Runoff Area=40,662 sf Runoff Volume=0.024 af Runoff Depth=0.31" Tc=10.0 min CN=61/98 0.27 cfs 18711_Central Auto Parking Addition (POST) MSE 24-hr 3 2-Year Rainfall=2.81"18711_POST Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 6HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Summary for Subcatchment N3: SOUTH OF EX. BLDG Runoff = 0.12 cfs @ 12.14 hrs, Volume= 0.008 af, Depth= 0.30" Routed to Reach R3 : OFFSITE - SOUTH Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.01 hrs MSE 24-hr 3 2-Year Rainfall=2.81" Area (sf) CN Description 13,806 61 >75% Grass cover, Good, HSG B 13,806 61 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment N3: SOUTH OF EX. BLDG Runoff Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086420 Fl o w ( c f s ) 0.13 0.125 0.12 0.115 0.11 0.105 0.1 0.095 0.09 0.085 0.08 0.075 0.07 0.065 0.06 0.055 0.05 0.045 0.04 0.035 0.03 0.025 0.02 0.015 0.01 0.005 0 MSE 24-hr 3 2-Year Rainfall=2.81" Runoff Area=13,806 sf Runoff Volume=0.008 af Runoff Depth=0.30" Tc=5.0 min CN=61/0 0.12 cfs 18711_Central Auto Parking Addition (POST) MSE 24-hr 3 2-Year Rainfall=2.81"18711_POST Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 7HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Summary for Subcatchment N4: N & W OF EX. LOT Runoff = 0.20 cfs @ 12.13 hrs, Volume= 0.011 af, Depth= 0.83" Routed to Reach R1 : OFFSITE - ROW Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.01 hrs MSE 24-hr 3 2-Year Rainfall=2.81" Area (sf) CN Description 5,321 61 >75% Grass cover, Good, HSG B 1,630 98 Paved parking, HSG B 6,951 70 Weighted Average 5,321 61 76.55% Pervious Area 1,630 98 23.45% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment N4: N & W OF EX. LOT Runoff Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086420 Fl o w ( c f s ) 0.22 0.21 0.2 0.19 0.18 0.17 0.16 0.15 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 MSE 24-hr 3 2-Year Rainfall=2.81" Runoff Area=6,951 sf Runoff Volume=0.011 af Runoff Depth=0.83" Tc=5.0 min CN=61/98 0.20 cfs 18711_Central Auto Parking Addition (POST) MSE 24-hr 3 2-Year Rainfall=2.81"18711_POST Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 8HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Summary for Reach R1: OFFSITE - ROW Inflow Area = 1.358 ac, 70.20% Impervious, Inflow Depth = 0.52" for 2-Year event Inflow = 0.20 cfs @ 13.13 hrs, Volume= 0.059 af Outflow = 0.20 cfs @ 13.13 hrs, Volume= 0.059 af, Atten= 0%, Lag= 0.0 min Routed to nonexistent node 1R Routing by Stor-Ind+Trans method, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs Reach R1: OFFSITE - ROW Inflow Outflow Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086420 Fl o w ( c f s ) 0.22 0.21 0.2 0.19 0.18 0.17 0.16 0.15 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 Inflow Area=1.358 ac 0.20 cfs 0.20 cfs 18711_Central Auto Parking Addition (POST) MSE 24-hr 3 2-Year Rainfall=2.81"18711_POST Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 9HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Summary for Reach R2: OFFSITE - EAST Inflow Area = 0.933 ac, 0.83% Impervious, Inflow Depth = 0.31" for 2-Year event Inflow = 0.27 cfs @ 12.22 hrs, Volume= 0.024 af Outflow = 0.27 cfs @ 12.22 hrs, Volume= 0.024 af, Atten= 0%, Lag= 0.0 min Routed to nonexistent node 1R Routing by Stor-Ind+Trans method, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs Reach R2: OFFSITE - EAST Inflow Outflow Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086420 Fl o w ( c f s ) 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 Inflow Area=0.933 ac 0.27 cfs 0.27 cfs 18711_Central Auto Parking Addition (POST) MSE 24-hr 3 2-Year Rainfall=2.81"18711_POST Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 10HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Summary for Reach R3: OFFSITE - SOUTH Inflow Area = 0.317 ac, 0.00% Impervious, Inflow Depth = 0.30" for 2-Year event Inflow = 0.12 cfs @ 12.14 hrs, Volume= 0.008 af Outflow = 0.12 cfs @ 12.14 hrs, Volume= 0.008 af, Atten= 0%, Lag= 0.0 min Routed to nonexistent node 1R Routing by Stor-Ind+Trans method, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs Reach R3: OFFSITE - SOUTH Inflow Outflow Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086420 Fl o w ( c f s ) 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 Inflow Area=0.317 ac 0.12 cfs 0.12 cfs 18711_Central Auto Parking Addition (POST) MSE 24-hr 3 2-Year Rainfall=2.81"18711_POST Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 11HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Summary for Pond P2: EXPANDED POND Inflow Area = 1.198 ac, 76.43% Impervious, Inflow Depth = 2.04" for 2-Year event Inflow = 4.04 cfs @ 12.12 hrs, Volume= 0.204 af Outflow = 0.23 cfs @ 13.18 hrs, Volume= 0.204 af, Atten= 94%, Lag= 63.4 min Discarded = 0.05 cfs @ 13.18 hrs, Volume= 0.156 af Primary = 0.19 cfs @ 13.18 hrs, Volume= 0.048 af Routed to Reach R1 : OFFSITE - ROW Routing by Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs Peak Elev= 901.51' @ 13.18 hrs Surf.Area= 6,599 sf Storage= 5,735 cf Flood Elev= 905.00' Surf.Area= 10,500 sf Storage= 35,082 cf Plug-Flow detention time= 826.1 min calculated for 0.204 af (100% of inflow) Center-of-Mass det. time= 826.3 min ( 1,583.8 - 757.5 ) Volume Invert Avail.Storage Storage Description #1 900.50' 35,082 cf Custom Stage Data (Irregular) Listed below (Recalc) Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area (feet) (sq-ft) (feet) (cubic-feet) (cubic-feet) (sq-ft) 900.50 4,000 220.0 0 0 4,000 901.00 6,100 320.0 2,507 2,507 8,299 902.00 7,100 340.0 6,594 9,100 9,400 903.00 8,100 360.0 7,595 16,695 10,568 904.00 9,100 380.0 8,595 25,290 11,803 905.00 10,500 420.0 9,792 35,082 14,380 Device Routing Invert Outlet Devices #1 Primary 899.50'12.0" Round Culvert L= 185.0' RCP, end-section conforming to fill, Ke= 0.500 Inlet / Outlet Invert= 899.50' / 897.70' S= 0.0097 '/' Cc= 0.900 n= 0.011 Concrete pipe, straight & clean, Flow Area= 0.79 sf #2 Device 1 901.30'12.0" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads #3 Discarded 900.50'0.300 in/hr Exfiltration over Surface area above 900.00' Excluded Surface area = 0 sf Discarded OutFlow Max=0.05 cfs @ 13.18 hrs HW=901.51' (Free Discharge) 3=Exfiltration (Exfiltration Controls 0.05 cfs) Primary OutFlow Max=0.18 cfs @ 13.18 hrs HW=901.51' (Free Discharge) 1=Culvert (Passes 0.18 cfs of 4.44 cfs potential flow) 2=Orifice/Grate (Orifice Controls 0.18 cfs @ 1.55 fps) 18711_Central Auto Parking Addition (POST) MSE 24-hr 3 2-Year Rainfall=2.81"18711_POST Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 12HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Pond P2: EXPANDED POND Inflow Outflow Discarded Primary Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086420 Fl o w ( c f s ) 4 3 2 1 0 Inflow Area=1.198 ac Peak Elev=901.51' Storage=5,735 cf 4.04 cfs 0.23 cfs 0.05 cfs0.19 cfs 18711_Central Auto Parking Addition (POST) MSE 24-hr 3 2-Year Rainfall=2.81"18711_POST Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 13HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Stage-Area-Storage for Pond P2: EXPANDED POND Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 900.50 4,000 0 900.55 4,190 205 900.60 4,385 419 900.65 4,584 643 900.70 4,787 878 900.75 4,995 1,122 900.80 5,207 1,377 900.85 5,424 1,643 900.90 5,645 1,920 900.95 5,870 2,207 901.00 6,100 2,507 901.05 6,148 2,813 901.10 6,197 3,121 901.15 6,245 3,432 901.20 6,294 3,746 901.25 6,343 4,062 901.30 6,392 4,380 901.35 6,441 4,701 901.40 6,491 5,024 901.45 6,541 5,350 901.50 6,591 5,678 901.55 6,641 6,009 901.60 6,691 6,343 901.65 6,741 6,678 901.70 6,792 7,017 901.75 6,843 7,358 901.80 6,894 7,701 901.85 6,945 8,047 901.90 6,997 8,395 901.95 7,048 8,747 902.00 7,100 9,100 902.05 7,148 9,456 902.10 7,197 9,815 902.15 7,246 10,176 902.20 7,295 10,540 902.25 7,344 10,906 902.30 7,393 11,274 902.35 7,443 11,645 902.40 7,492 12,018 902.45 7,542 12,394 902.50 7,592 12,773 902.55 7,642 13,153 902.60 7,692 13,537 902.65 7,743 13,923 902.70 7,793 14,311 902.75 7,844 14,702 902.80 7,895 15,095 902.85 7,946 15,491 902.90 7,997 15,890 902.95 8,048 16,291 903.00 8,100 16,695 Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 903.05 8,149 17,101 903.10 8,197 17,510 903.15 8,246 17,921 903.20 8,295 18,334 903.25 8,345 18,750 903.30 8,394 19,169 903.35 8,443 19,590 903.40 8,493 20,013 903.45 8,543 20,439 903.50 8,593 20,867 903.55 8,643 21,298 903.60 8,693 21,732 903.65 8,743 22,168 903.70 8,794 22,606 903.75 8,845 23,047 903.80 8,895 23,490 903.85 8,946 23,936 903.90 8,997 24,385 903.95 9,049 24,836 904.00 9,100 25,290 904.05 9,168 25,747 904.10 9,235 26,207 904.15 9,304 26,670 904.20 9,372 27,137 904.25 9,441 27,607 904.30 9,509 28,081 904.35 9,579 28,558 904.40 9,648 29,039 904.45 9,718 29,523 904.50 9,787 30,011 904.55 9,858 30,502 904.60 9,928 30,997 904.65 9,999 31,495 904.70 10,069 31,996 904.75 10,141 32,502 904.80 10,212 33,010 904.85 10,284 33,523 904.90 10,355 34,039 904.95 10,428 34,558 905.00 10,500 35,082 18711_Central Auto Parking Addition (POST) MSE 24-hr 3 10-Year Rainfall=4.17"18711_POST Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 14HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Time span=0.00-72.00 hrs, dt=0.01 hrs, 7201 points Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv. Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=52,186 sf 76.43% Impervious Runoff Depth=3.22"Subcatchment N1: EX. BLDG & NEW LOT Tc=5.0 min CN=61/98 Runoff=6.35 cfs 0.321 af Runoff Area=40,662 sf 0.83% Impervious Runoff Depth=0.93"Subcatchment N2: EAST OF EX. POND Tc=10.0 min CN=61/98 Runoff=1.19 cfs 0.072 af Runoff Area=13,806 sf 0.00% Impervious Runoff Depth=0.90"Subcatchment N3: SOUTH OF EX. BLDG Tc=5.0 min CN=61/0 Runoff=0.52 cfs 0.024 af Runoff Area=6,951 sf 23.45% Impervious Runoff Depth=1.61"Subcatchment N4: N & W OF EX. LOT Tc=5.0 min CN=61/98 Runoff=0.44 cfs 0.021 af Inflow=1.09 cfs 0.177 afReach R1: OFFSITE - ROW Outflow=1.09 cfs 0.177 af Inflow=1.19 cfs 0.072 afReach R2: OFFSITE - EAST Outflow=1.19 cfs 0.072 af Inflow=0.52 cfs 0.024 afReach R3: OFFSITE - SOUTH Outflow=0.52 cfs 0.024 af Peak Elev=901.82' Storage=7,812 cf Inflow=6.35 cfs 0.321 afPond P2: EXPANDED POND Discarded=0.05 cfs 0.166 af Primary=1.00 cfs 0.155 af Outflow=1.05 cfs 0.321 af Total Runoff Area = 2.608 ac Runoff Volume = 0.439 af Average Runoff Depth = 2.02" 63.16% Pervious = 1.647 ac 36.84% Impervious = 0.961 ac 18711_Central Auto Parking Addition (POST) MSE 24-hr 3 10-Year Rainfall=4.17"18711_POST Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 15HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Summary for Subcatchment N1: EX. BLDG & NEW LOT Runoff = 6.35 cfs @ 12.12 hrs, Volume= 0.321 af, Depth= 3.22" Routed to Pond P2 : EXPANDED POND Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.01 hrs MSE 24-hr 3 10-Year Rainfall=4.17" Area (sf) CN Description 12,302 61 >75% Grass cover, Good, HSG B 33,473 98 Paved parking, HSG B 6,411 98 Water Surface, HSG B 52,186 89 Weighted Average 12,302 61 23.57% Pervious Area 39,884 98 76.43% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment N1: EX. BLDG & NEW LOT Runoff Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086420 Fl o w ( c f s ) 7 6 5 4 3 2 1 0 MSE 24-hr 3 10-Year Rainfall=4.17" Runoff Area=52,186 sf Runoff Volume=0.321 af Runoff Depth=3.22" Tc=5.0 min CN=61/98 6.35 cfs 18711_Central Auto Parking Addition (POST) MSE 24-hr 3 10-Year Rainfall=4.17"18711_POST Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 16HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Summary for Subcatchment N2: EAST OF EX. POND Runoff = 1.19 cfs @ 12.19 hrs, Volume= 0.072 af, Depth= 0.93" Routed to Reach R2 : OFFSITE - EAST Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.01 hrs MSE 24-hr 3 10-Year Rainfall=4.17" Area (sf) CN Description 40,326 61 >75% Grass cover, Good, HSG B 336 98 Paved parking, HSG B 40,662 61 Weighted Average 40,326 61 99.17% Pervious Area 336 98 0.83% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Subcatchment N2: EAST OF EX. POND Runoff Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086420 Fl o w ( c f s ) 1 0 MSE 24-hr 3 10-Year Rainfall=4.17" Runoff Area=40,662 sf Runoff Volume=0.072 af Runoff Depth=0.93" Tc=10.0 min CN=61/98 1.19 cfs 18711_Central Auto Parking Addition (POST) MSE 24-hr 3 10-Year Rainfall=4.17"18711_POST Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 17HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Summary for Subcatchment N3: SOUTH OF EX. BLDG Runoff = 0.52 cfs @ 12.13 hrs, Volume= 0.024 af, Depth= 0.90" Routed to Reach R3 : OFFSITE - SOUTH Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.01 hrs MSE 24-hr 3 10-Year Rainfall=4.17" Area (sf) CN Description 13,806 61 >75% Grass cover, Good, HSG B 13,806 61 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment N3: SOUTH OF EX. BLDG Runoff Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086420 Fl o w ( c f s ) 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=4.17" Runoff Area=13,806 sf Runoff Volume=0.024 af Runoff Depth=0.90" Tc=5.0 min CN=61/0 0.52 cfs 18711_Central Auto Parking Addition (POST) MSE 24-hr 3 10-Year Rainfall=4.17"18711_POST Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 18HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Summary for Subcatchment N4: N & W OF EX. LOT Runoff = 0.44 cfs @ 12.13 hrs, Volume= 0.021 af, Depth= 1.61" Routed to Reach R1 : OFFSITE - ROW Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.01 hrs MSE 24-hr 3 10-Year Rainfall=4.17" Area (sf) CN Description 5,321 61 >75% Grass cover, Good, HSG B 1,630 98 Paved parking, HSG B 6,951 70 Weighted Average 5,321 61 76.55% Pervious Area 1,630 98 23.45% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment N4: N & W OF EX. LOT Runoff Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086420 Fl o w ( c f s ) 0.48 0.46 0.44 0.42 0.4 0.38 0.36 0.34 0.32 0.3 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 MSE 24-hr 3 10-Year Rainfall=4.17" Runoff Area=6,951 sf Runoff Volume=0.021 af Runoff Depth=1.61" Tc=5.0 min CN=61/98 0.44 cfs 18711_Central Auto Parking Addition (POST) MSE 24-hr 3 10-Year Rainfall=4.17"18711_POST Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 19HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Summary for Reach R1: OFFSITE - ROW Inflow Area = 1.358 ac, 70.20% Impervious, Inflow Depth = 1.56" for 10-Year event Inflow = 1.09 cfs @ 12.36 hrs, Volume= 0.177 af Outflow = 1.09 cfs @ 12.36 hrs, Volume= 0.177 af, Atten= 0%, Lag= 0.0 min Routed to nonexistent node 1R Routing by Stor-Ind+Trans method, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs Reach R1: OFFSITE - ROW Inflow Outflow Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086420 Fl o w ( c f s ) 1 0 Inflow Area=1.358 ac 1.09 cfs 1.09 cfs 18711_Central Auto Parking Addition (POST) MSE 24-hr 3 10-Year Rainfall=4.17"18711_POST Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 20HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Summary for Reach R2: OFFSITE - EAST Inflow Area = 0.933 ac, 0.83% Impervious, Inflow Depth = 0.93" for 10-Year event Inflow = 1.19 cfs @ 12.19 hrs, Volume= 0.072 af Outflow = 1.19 cfs @ 12.19 hrs, Volume= 0.072 af, Atten= 0%, Lag= 0.0 min Routed to nonexistent node 1R Routing by Stor-Ind+Trans method, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs Reach R2: OFFSITE - EAST Inflow Outflow Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086420 Fl o w ( c f s ) 1 0 Inflow Area=0.933 ac 1.19 cfs 1.19 cfs 18711_Central Auto Parking Addition (POST) MSE 24-hr 3 10-Year Rainfall=4.17"18711_POST Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 21HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Summary for Reach R3: OFFSITE - SOUTH Inflow Area = 0.317 ac, 0.00% Impervious, Inflow Depth = 0.90" for 10-Year event Inflow = 0.52 cfs @ 12.13 hrs, Volume= 0.024 af Outflow = 0.52 cfs @ 12.13 hrs, Volume= 0.024 af, Atten= 0%, Lag= 0.0 min Routed to nonexistent node 1R Routing by Stor-Ind+Trans method, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs Reach R3: OFFSITE - SOUTH Inflow Outflow Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086420 Fl o w ( c f s ) 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=0.317 ac 0.52 cfs 0.52 cfs 18711_Central Auto Parking Addition (POST) MSE 24-hr 3 10-Year Rainfall=4.17"18711_POST Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 22HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Summary for Pond P2: EXPANDED POND Inflow Area = 1.198 ac, 76.43% Impervious, Inflow Depth = 3.22" for 10-Year event Inflow = 6.35 cfs @ 12.12 hrs, Volume= 0.321 af Outflow = 1.05 cfs @ 12.44 hrs, Volume= 0.321 af, Atten= 84%, Lag= 18.9 min Discarded = 0.05 cfs @ 12.44 hrs, Volume= 0.166 af Primary = 1.00 cfs @ 12.44 hrs, Volume= 0.155 af Routed to Reach R1 : OFFSITE - ROW Routing by Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs Peak Elev= 901.82' @ 12.44 hrs Surf.Area= 6,910 sf Storage= 7,812 cf Flood Elev= 905.00' Surf.Area= 10,500 sf Storage= 35,082 cf Plug-Flow detention time= 582.9 min calculated for 0.321 af (100% of inflow) Center-of-Mass det. time= 583.1 min ( 1,336.5 - 753.3 ) Volume Invert Avail.Storage Storage Description #1 900.50' 35,082 cf Custom Stage Data (Irregular) Listed below (Recalc) Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area (feet) (sq-ft) (feet) (cubic-feet) (cubic-feet) (sq-ft) 900.50 4,000 220.0 0 0 4,000 901.00 6,100 320.0 2,507 2,507 8,299 902.00 7,100 340.0 6,594 9,100 9,400 903.00 8,100 360.0 7,595 16,695 10,568 904.00 9,100 380.0 8,595 25,290 11,803 905.00 10,500 420.0 9,792 35,082 14,380 Device Routing Invert Outlet Devices #1 Primary 899.50'12.0" Round Culvert L= 185.0' RCP, end-section conforming to fill, Ke= 0.500 Inlet / Outlet Invert= 899.50' / 897.70' S= 0.0097 '/' Cc= 0.900 n= 0.011 Concrete pipe, straight & clean, Flow Area= 0.79 sf #2 Device 1 901.30'12.0" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads #3 Discarded 900.50'0.300 in/hr Exfiltration over Surface area above 900.00' Excluded Surface area = 0 sf Discarded OutFlow Max=0.05 cfs @ 12.44 hrs HW=901.82' (Free Discharge) 3=Exfiltration (Exfiltration Controls 0.05 cfs) Primary OutFlow Max=1.00 cfs @ 12.44 hrs HW=901.82' (Free Discharge) 1=Culvert (Passes 1.00 cfs of 4.68 cfs potential flow) 2=Orifice/Grate (Orifice Controls 1.00 cfs @ 2.45 fps) 18711_Central Auto Parking Addition (POST) MSE 24-hr 3 10-Year Rainfall=4.17"18711_POST Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 23HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Pond P2: EXPANDED POND Inflow Outflow Discarded Primary Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086420 Fl o w ( c f s ) 7 6 5 4 3 2 1 0 Inflow Area=1.198 ac Peak Elev=901.82' Storage=7,812 cf 6.35 cfs 1.05 cfs 0.05 cfs 1.00 cfs 18711_Central Auto Parking Addition (POST) MSE 24-hr 3 10-Year Rainfall=4.17"18711_POST Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 24HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Stage-Area-Storage for Pond P2: EXPANDED POND Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 900.50 4,000 0 900.55 4,190 205 900.60 4,385 419 900.65 4,584 643 900.70 4,787 878 900.75 4,995 1,122 900.80 5,207 1,377 900.85 5,424 1,643 900.90 5,645 1,920 900.95 5,870 2,207 901.00 6,100 2,507 901.05 6,148 2,813 901.10 6,197 3,121 901.15 6,245 3,432 901.20 6,294 3,746 901.25 6,343 4,062 901.30 6,392 4,380 901.35 6,441 4,701 901.40 6,491 5,024 901.45 6,541 5,350 901.50 6,591 5,678 901.55 6,641 6,009 901.60 6,691 6,343 901.65 6,741 6,678 901.70 6,792 7,017 901.75 6,843 7,358 901.80 6,894 7,701 901.85 6,945 8,047 901.90 6,997 8,395 901.95 7,048 8,747 902.00 7,100 9,100 902.05 7,148 9,456 902.10 7,197 9,815 902.15 7,246 10,176 902.20 7,295 10,540 902.25 7,344 10,906 902.30 7,393 11,274 902.35 7,443 11,645 902.40 7,492 12,018 902.45 7,542 12,394 902.50 7,592 12,773 902.55 7,642 13,153 902.60 7,692 13,537 902.65 7,743 13,923 902.70 7,793 14,311 902.75 7,844 14,702 902.80 7,895 15,095 902.85 7,946 15,491 902.90 7,997 15,890 902.95 8,048 16,291 903.00 8,100 16,695 Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 903.05 8,149 17,101 903.10 8,197 17,510 903.15 8,246 17,921 903.20 8,295 18,334 903.25 8,345 18,750 903.30 8,394 19,169 903.35 8,443 19,590 903.40 8,493 20,013 903.45 8,543 20,439 903.50 8,593 20,867 903.55 8,643 21,298 903.60 8,693 21,732 903.65 8,743 22,168 903.70 8,794 22,606 903.75 8,845 23,047 903.80 8,895 23,490 903.85 8,946 23,936 903.90 8,997 24,385 903.95 9,049 24,836 904.00 9,100 25,290 904.05 9,168 25,747 904.10 9,235 26,207 904.15 9,304 26,670 904.20 9,372 27,137 904.25 9,441 27,607 904.30 9,509 28,081 904.35 9,579 28,558 904.40 9,648 29,039 904.45 9,718 29,523 904.50 9,787 30,011 904.55 9,858 30,502 904.60 9,928 30,997 904.65 9,999 31,495 904.70 10,069 31,996 904.75 10,141 32,502 904.80 10,212 33,010 904.85 10,284 33,523 904.90 10,355 34,039 904.95 10,428 34,558 905.00 10,500 35,082 18711_Central Auto Parking Addition (POST) MSE 24-hr 3 100-Year Rainfall=7.20"18711_POST Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 25HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Time span=0.00-72.00 hrs, dt=0.01 hrs, 7201 points Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv. Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=52,186 sf 76.43% Impervious Runoff Depth=5.99"Subcatchment N1: EX. BLDG & NEW LOT Tc=5.0 min CN=61/98 Runoff=11.80 cfs 0.598 af Runoff Area=40,662 sf 0.83% Impervious Runoff Depth=2.88"Subcatchment N2: EAST OF EX. POND Tc=10.0 min CN=61/98 Runoff=4.14 cfs 0.224 af Runoff Area=13,806 sf 0.00% Impervious Runoff Depth=2.85"Subcatchment N3: SOUTH OF EX. BLDG Tc=5.0 min CN=61/0 Runoff=1.77 cfs 0.075 af Runoff Area=6,951 sf 23.45% Impervious Runoff Depth=3.81"Subcatchment N4: N & W OF EX. LOT Tc=5.0 min CN=61/98 Runoff=1.10 cfs 0.051 af Inflow=3.79 cfs 0.471 afReach R1: OFFSITE - ROW Outflow=3.79 cfs 0.471 af Inflow=4.14 cfs 0.224 afReach R2: OFFSITE - EAST Outflow=4.14 cfs 0.224 af Inflow=1.77 cfs 0.075 afReach R3: OFFSITE - SOUTH Outflow=1.77 cfs 0.075 af Peak Elev=902.50' Storage=12,806 cf Inflow=11.80 cfs 0.598 afPond P2: EXPANDED POND Discarded=0.05 cfs 0.178 af Primary=3.17 cfs 0.420 af Outflow=3.23 cfs 0.598 af Total Runoff Area = 2.608 ac Runoff Volume = 0.948 af Average Runoff Depth = 4.36" 63.16% Pervious = 1.647 ac 36.84% Impervious = 0.961 ac 18711_Central Auto Parking Addition (POST) MSE 24-hr 3 100-Year Rainfall=7.20"18711_POST Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 26HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Summary for Subcatchment N1: EX. BLDG & NEW LOT Runoff = 11.80 cfs @ 12.12 hrs, Volume= 0.598 af, Depth= 5.99" Routed to Pond P2 : EXPANDED POND Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.01 hrs MSE 24-hr 3 100-Year Rainfall=7.20" Area (sf) CN Description 12,302 61 >75% Grass cover, Good, HSG B 33,473 98 Paved parking, HSG B 6,411 98 Water Surface, HSG B 52,186 89 Weighted Average 12,302 61 23.57% Pervious Area 39,884 98 76.43% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment N1: EX. BLDG & NEW LOT Runoff Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086420 Fl o w ( c f s ) 13 12 11 10 9 8 7 6 5 4 3 2 1 0 MSE 24-hr 3 100-Year Rainfall=7.20" Runoff Area=52,186 sf Runoff Volume=0.598 af Runoff Depth=5.99" Tc=5.0 min CN=61/98 11.80 cfs 18711_Central Auto Parking Addition (POST) MSE 24-hr 3 100-Year Rainfall=7.20"18711_POST Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 27HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Summary for Subcatchment N2: EAST OF EX. POND Runoff = 4.14 cfs @ 12.18 hrs, Volume= 0.224 af, Depth= 2.88" Routed to Reach R2 : OFFSITE - EAST Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.01 hrs MSE 24-hr 3 100-Year Rainfall=7.20" Area (sf) CN Description 40,326 61 >75% Grass cover, Good, HSG B 336 98 Paved parking, HSG B 40,662 61 Weighted Average 40,326 61 99.17% Pervious Area 336 98 0.83% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Subcatchment N2: EAST OF EX. POND Runoff Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086420 Fl o w ( c f s ) 4 3 2 1 0 MSE 24-hr 3 100-Year Rainfall=7.20" Runoff Area=40,662 sf Runoff Volume=0.224 af Runoff Depth=2.88" Tc=10.0 min CN=61/98 4.14 cfs 18711_Central Auto Parking Addition (POST) MSE 24-hr 3 100-Year Rainfall=7.20"18711_POST Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 28HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Summary for Subcatchment N3: SOUTH OF EX. BLDG Runoff = 1.77 cfs @ 12.13 hrs, Volume= 0.075 af, Depth= 2.85" Routed to Reach R3 : OFFSITE - SOUTH Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.01 hrs MSE 24-hr 3 100-Year Rainfall=7.20" Area (sf) CN Description 13,806 61 >75% Grass cover, Good, HSG B 13,806 61 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment N3: SOUTH OF EX. BLDG Runoff Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086420 Fl o w ( c f s ) 1 0 MSE 24-hr 3 100-Year Rainfall=7.20" Runoff Area=13,806 sf Runoff Volume=0.075 af Runoff Depth=2.85" Tc=5.0 min CN=61/0 1.77 cfs 18711_Central Auto Parking Addition (POST) MSE 24-hr 3 100-Year Rainfall=7.20"18711_POST Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 29HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Summary for Subcatchment N4: N & W OF EX. LOT Runoff = 1.10 cfs @ 12.13 hrs, Volume= 0.051 af, Depth= 3.81" Routed to Reach R1 : OFFSITE - ROW Runoff by SCS TR-20 method, UH=SCS, Split Pervious/Imperv., Time Span= 0.00-72.00 hrs, dt= 0.01 hrs MSE 24-hr 3 100-Year Rainfall=7.20" Area (sf) CN Description 5,321 61 >75% Grass cover, Good, HSG B 1,630 98 Paved parking, HSG B 6,951 70 Weighted Average 5,321 61 76.55% Pervious Area 1,630 98 23.45% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment N4: N & W OF EX. LOT Runoff Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086420 Fl o w ( c f s ) 1 0 MSE 24-hr 3 100-Year Rainfall=7.20" Runoff Area=6,951 sf Runoff Volume=0.051 af Runoff Depth=3.81" Tc=5.0 min CN=61/98 1.10 cfs 18711_Central Auto Parking Addition (POST) MSE 24-hr 3 100-Year Rainfall=7.20"18711_POST Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 30HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Summary for Reach R1: OFFSITE - ROW Inflow Area = 1.358 ac, 70.20% Impervious, Inflow Depth = 4.16" for 100-Year event Inflow = 3.79 cfs @ 12.15 hrs, Volume= 0.471 af Outflow = 3.79 cfs @ 12.15 hrs, Volume= 0.471 af, Atten= 0%, Lag= 0.0 min Routed to nonexistent node 1R Routing by Stor-Ind+Trans method, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs Reach R1: OFFSITE - ROW Inflow Outflow Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086420 Fl o w ( c f s ) 4 3 2 1 0 Inflow Area=1.358 ac 3.79 cfs 3.79 cfs 18711_Central Auto Parking Addition (POST) MSE 24-hr 3 100-Year Rainfall=7.20"18711_POST Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 31HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Summary for Reach R2: OFFSITE - EAST Inflow Area = 0.933 ac, 0.83% Impervious, Inflow Depth = 2.88" for 100-Year event Inflow = 4.14 cfs @ 12.18 hrs, Volume= 0.224 af Outflow = 4.14 cfs @ 12.18 hrs, Volume= 0.224 af, Atten= 0%, Lag= 0.0 min Routed to nonexistent node 1R Routing by Stor-Ind+Trans method, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs Reach R2: OFFSITE - EAST Inflow Outflow Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086420 Fl o w ( c f s ) 4 3 2 1 0 Inflow Area=0.933 ac 4.14 cfs 4.14 cfs 18711_Central Auto Parking Addition (POST) MSE 24-hr 3 100-Year Rainfall=7.20"18711_POST Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 32HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Summary for Reach R3: OFFSITE - SOUTH Inflow Area = 0.317 ac, 0.00% Impervious, Inflow Depth = 2.85" for 100-Year event Inflow = 1.77 cfs @ 12.13 hrs, Volume= 0.075 af Outflow = 1.77 cfs @ 12.13 hrs, Volume= 0.075 af, Atten= 0%, Lag= 0.0 min Routed to nonexistent node 1R Routing by Stor-Ind+Trans method, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs Reach R3: OFFSITE - SOUTH Inflow Outflow Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086420 Fl o w ( c f s ) 1 0 Inflow Area=0.317 ac 1.77 cfs 1.77 cfs 18711_Central Auto Parking Addition (POST) MSE 24-hr 3 100-Year Rainfall=7.20"18711_POST Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 33HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Summary for Pond P2: EXPANDED POND Inflow Area = 1.198 ac, 76.43% Impervious, Inflow Depth = 5.99" for 100-Year event Inflow = 11.80 cfs @ 12.12 hrs, Volume= 0.598 af Outflow = 3.23 cfs @ 12.28 hrs, Volume= 0.598 af, Atten= 73%, Lag= 9.6 min Discarded = 0.05 cfs @ 12.28 hrs, Volume= 0.178 af Primary = 3.17 cfs @ 12.28 hrs, Volume= 0.420 af Routed to Reach R1 : OFFSITE - ROW Routing by Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs Peak Elev= 902.50' @ 12.28 hrs Surf.Area= 7,596 sf Storage= 12,806 cf Flood Elev= 905.00' Surf.Area= 10,500 sf Storage= 35,082 cf Plug-Flow detention time= 363.4 min calculated for 0.598 af (100% of inflow) Center-of-Mass det. time= 363.4 min ( 1,112.0 - 748.6 ) Volume Invert Avail.Storage Storage Description #1 900.50' 35,082 cf Custom Stage Data (Irregular) Listed below (Recalc) Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area (feet) (sq-ft) (feet) (cubic-feet) (cubic-feet) (sq-ft) 900.50 4,000 220.0 0 0 4,000 901.00 6,100 320.0 2,507 2,507 8,299 902.00 7,100 340.0 6,594 9,100 9,400 903.00 8,100 360.0 7,595 16,695 10,568 904.00 9,100 380.0 8,595 25,290 11,803 905.00 10,500 420.0 9,792 35,082 14,380 Device Routing Invert Outlet Devices #1 Primary 899.50'12.0" Round Culvert L= 185.0' RCP, end-section conforming to fill, Ke= 0.500 Inlet / Outlet Invert= 899.50' / 897.70' S= 0.0097 '/' Cc= 0.900 n= 0.011 Concrete pipe, straight & clean, Flow Area= 0.79 sf #2 Device 1 901.30'12.0" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads #3 Discarded 900.50'0.300 in/hr Exfiltration over Surface area above 900.00' Excluded Surface area = 0 sf Discarded OutFlow Max=0.05 cfs @ 12.28 hrs HW=902.50' (Free Discharge) 3=Exfiltration (Exfiltration Controls 0.05 cfs) Primary OutFlow Max=3.17 cfs @ 12.28 hrs HW=902.50' (Free Discharge) 1=Culvert (Passes 3.17 cfs of 5.17 cfs potential flow) 2=Orifice/Grate (Orifice Controls 3.17 cfs @ 4.04 fps) 18711_Central Auto Parking Addition (POST) MSE 24-hr 3 100-Year Rainfall=7.20"18711_POST Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 34HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Pond P2: EXPANDED POND Inflow Outflow Discarded Primary Hydrograph Time (hours) 727068666462605856545250484644424038363432302826242220181614121086420 Fl o w ( c f s ) 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Inflow Area=1.198 ac Peak Elev=902.50' Storage=12,806 cf 11.80 cfs 3.23 cfs 0.05 cfs 3.17 cfs 18711_Central Auto Parking Addition (POST) MSE 24-hr 3 100-Year Rainfall=7.20"18711_POST Printed 7/24/2025Prepared by Anderson Engineering Of MN, LLC Page 35HydroCAD® 10.20-6a s/n 00837 © 2024 HydroCAD Software Solutions LLC Stage-Area-Storage for Pond P2: EXPANDED POND Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 900.50 4,000 0 900.55 4,190 205 900.60 4,385 419 900.65 4,584 643 900.70 4,787 878 900.75 4,995 1,122 900.80 5,207 1,377 900.85 5,424 1,643 900.90 5,645 1,920 900.95 5,870 2,207 901.00 6,100 2,507 901.05 6,148 2,813 901.10 6,197 3,121 901.15 6,245 3,432 901.20 6,294 3,746 901.25 6,343 4,062 901.30 6,392 4,380 901.35 6,441 4,701 901.40 6,491 5,024 901.45 6,541 5,350 901.50 6,591 5,678 901.55 6,641 6,009 901.60 6,691 6,343 901.65 6,741 6,678 901.70 6,792 7,017 901.75 6,843 7,358 901.80 6,894 7,701 901.85 6,945 8,047 901.90 6,997 8,395 901.95 7,048 8,747 902.00 7,100 9,100 902.05 7,148 9,456 902.10 7,197 9,815 902.15 7,246 10,176 902.20 7,295 10,540 902.25 7,344 10,906 902.30 7,393 11,274 902.35 7,443 11,645 902.40 7,492 12,018 902.45 7,542 12,394 902.50 7,592 12,773 902.55 7,642 13,153 902.60 7,692 13,537 902.65 7,743 13,923 902.70 7,793 14,311 902.75 7,844 14,702 902.80 7,895 15,095 902.85 7,946 15,491 902.90 7,997 15,890 902.95 8,048 16,291 903.00 8,100 16,695 Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 903.05 8,149 17,101 903.10 8,197 17,510 903.15 8,246 17,921 903.20 8,295 18,334 903.25 8,345 18,750 903.30 8,394 19,169 903.35 8,443 19,590 903.40 8,493 20,013 903.45 8,543 20,439 903.50 8,593 20,867 903.55 8,643 21,298 903.60 8,693 21,732 903.65 8,743 22,168 903.70 8,794 22,606 903.75 8,845 23,047 903.80 8,895 23,490 903.85 8,946 23,936 903.90 8,997 24,385 903.95 9,049 24,836 904.00 9,100 25,290 904.05 9,168 25,747 904.10 9,235 26,207 904.15 9,304 26,670 904.20 9,372 27,137 904.25 9,441 27,607 904.30 9,509 28,081 904.35 9,579 28,558 904.40 9,648 29,039 904.45 9,718 29,523 904.50 9,787 30,011 904.55 9,858 30,502 904.60 9,928 30,997 904.65 9,999 31,495 904.70 10,069 31,996 904.75 10,141 32,502 904.80 10,212 33,010 904.85 10,284 33,523 904.90 10,355 34,039 904.95 10,428 34,558 905.00 10,500 35,082 FL/HP 906.57 FL 90 6 . 2 2 FL 906.51 FL 906.11 FL 905.93 FL 906.08 FL/HP 906.39 FL 905.34 TC/FL/EO 905.40 FL 905.27FL 905.19 FL 905.40 FL 905.19 FL 905.27 FL 904.96 RIM 904.90 FL 905.34 FL/HP 905.98 FL 905.76 TC/FL 905.91 FL/HP 905.73 TC/FL 905.91 TC/FL/LP 905.50 RIM 905.32 FL 905.73 ME/FL 906.05 TC/FL 906.00 FL/HP/EO 905.50 FL 905.32 ME 906.09 ME 906.23 ME 906.45 ME 906.19 ME 906.06 RIM 905.33 INV 901.30 ME/FL 906.13 ME/FL 906.52 ME/FL 906.30 ME/FL 906.29 ME/FL 906.28 ME/TC 906.54 ME/TC 906.62 ME/TC 905.77 ME/TC 905.51 ME/TC 905.31 ME/TC 905.00 ME 905.74 ME 9 0 4 . 6 3 ME 904.00 ME 9 0 1 . 0 0 ME 9 0 1 . 0 0 ME 906.35 ME 903.00 ME 903.36 ME 904.70 ME 901.66 ME 902.85 ME 898.40 ME 897.00 ME 896.00 ME 896.00 ME 897.44 ME 897.43 ME 897.24 ME 897.18 ME 897.38 ME 897.67 ME 899.28 ME 900.87 ME 902.11 ME 902.61 ME 904.29 ME/TC 905.02 FL/HP 906.75 ME 9 0 4 . 0 0 FG/HP 906.04 FG/HP 905.65 PLOTTED:COMM. NO. DRAWING NO. ----18711 CENTRAL AUTOMOTIVE PARKING LOT ADDITION 14819 59TH ST N OAK PARK HEIGHTS, MINNESOTA 55082 1 3 6 0 5 1 s t A v e n u e N . #1 0 0 P l y m o u t h , M N 5 5 4 4 1 | a e -m n .c o m P 7 6 3 .4 1 2 .4 0 0 0 | F 7 6 3 .4 1 2 .4 0 9 0 A n d e r s o n E n g i n e e r i n g o f M i n n e s o t a , L L C DRAWING TITLE CHECKED BY:DRAWN:DESIGNED: DMMDMMDMM 7/25/2025 REVISION LOG DESCRIPTION OF REVISIONSNO.DATE CITY & MSCWMO SUBMITTAL 62823 DREW MESSMER, PEPRINT NAME: SIGNATURE: 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. DATE:LICENSE NO.7/25/2025 0 20' N EX. BUILDING (55 TOTAL STALLS PROV'D) GRADING, DRAINAGE, & EROSION CONTROL PLAN CG101 40' LEGEND PROPERTY LINE EX. EASEMENT LINE NEW D & U EASEMENT LINE EX. MAJOR CONTOUR EX. MINOR CONTOUR PROPOSED MAJOR CONTOUR PROPOSED MINOR CONTOUR GRADE BREAK / FLOW LINE EX. CONCRETE CURB & GUTTER NEW CURBING (IN-FLOW) NEW CURBING (OUT-FLOW) EX. STORM SEWER NEW STORM SEWER NEW STORM STRUCTURES DRAINAGE ARROW FINISHED GRADE ELEVATION FLOW LINE OF GUTTER / SWALE HIGH POINT LOW POINT RIM ELEVATION MATCH EXISTING GRADE EMERGENCY OVERFLOW SILT FENCE INLET PROTECTION RIPRAP CONSTRUCTION ENTRANCE EROSION CONTROL BLANKET HP 900.1 FL 900.1 RIM 900.1 ME 900.1 FG 900.1 LP 900.1 EO 900.1 1.TOPOGRAPHIC SURVEY INFORMATION SHOWN HEREON, SHALL BE VERIFIED PRIOR COMMENCEMENT OF GRADING WORK. 2.CONTRACTOR AND OWNER ARE RESPONSIBLE FOR NPDES PERMIT APPLICATION. 3.PROPOSED SPOT ELEVATIONS REPRESENT FINISHED SURFACE GRADE, OR GUTTER GRADE IF SHOWN ON NEW CURB. 4.ALL PROPOSED CURB TRANSITIONS, OPENING/CUTS, AND TAPER AREAS SHALL BE REFERENCED ON THE SITE PLAN SHEET CS101. 5.LOCATION & TOP ELEVATIONS OF INLET & STRUCTURE RIMS/CASTINGS MAY NEED TO BE ADJUSTED IN THE FIELD THE BY CONTRACTOR WHERE NECESSARY & SHALL BE APPROVED BY THE ENGINEER. 6.TAKE ALL NECESSARY PRECAUTIONS TO PROTECT EXISTING UTILITIES. LOCATIONS OF UTILITIES SHOWN ARE BASED ON SURVEY AND/OR AS-BUILT INFORMATION AND MAY NOT REPRESENT ACTUAL CONDITIONS. CONTRACTOR IS RESPONSIBLE FOR UTILIZING UTILITY LOCATES PRIOR TO STARTING ANY WORK. 7.CONTRACTOR SHALL REMOVE ANY/ALL TRACKED SEDIMENT FROM ADJACENT ROADWAYS, WITHIN 24 HOURS OF DISCOVERY. 8.PERIMETER EROSION MUST BE INSTALLED AND INSPECTED BY THE CITY REPRESENTATIVE PRIOR TO FURTHER CONSTRUCTION ACTIVITY. PROVIDE 24 HOUR NOTICE. CONTRACTOR NOTES 1.GRADING CONTRACTOR SHALL VERIFY LOCATIONS AND ELEVATIONS OF ALL UNDERGROUND UTILITIES WITH THE RESPECTIVE UTILITY COMPANIES PRIOR TO CONSTRUCTION 2.GRADING CONTRACTOR SHALL PROVIDE AND MAINTAIN ALL EROSION CONTROL MEASURES SHOWN. GRADING CONTRACTOR SHALL IMPLEMENT ANY ADDITIONAL EROSION CONTROL MEASURES REQUIRED TO PROTECT ADJACENT PROPERTY. 3.ALL EROSION CONTROL FACILITIES SHALL BE MAINTAINED BY THE CONTRACTOR DURING GRADING OPERATIONS. 4.THE GRADING CONTRACTOR SHALL SCHEDULE THE SOILS ENGINEER SO THAT CERTIFICATION OF ALL CONTROLLED FILLS WILL BE FURNISHED TO THE OWNER DURING CONSTRUCTION AND UPON COMPLETION OF THE PROJECT. 5.ALL DISTURBED AREAS, EXCEPT AREAS TO BE PAVED AND/OR SPECIFICALLY DESIGNED BY A LANDSCAPE PLAN, SHALL BE COVERED WITH A MINIMUM 6" OF TOP SOIL. ALL DISTURBED AREAS SHALL BE SEEDED & MULCHED WITHIN 72 HOURS OF FINAL GRADING. SEED MIX:MNDOT NO. 25-131 220#/ACRE MULCH:TYPE 1 2 TONS/ACRE (DISK ANCHORED) FERTILIZER:150#/ACRE RATE OF APPLICATION 20-10-10 ALL EXPOSED SOIL AREAS WITH A CONTINUOUS POSITIVE SLOPE WITHIN 200 LINEAL FEET OF ANY SURFACE WATER, MUST HAVE TEMPORARY EROSION PROTECTION OR PERMANENT COVER FOR THE EXPOSED SOIL AREAS YEAR ROUND, ACCORDING TO THE FOLLOWING TABLE: TYPE OF SLOPE TIME: STEEPER THAN 3:1 7 DAYS 10:1 TO 3:1 14 DAYS FLATTER THAN 10:1 14 DAYS (MAXIMUM TIME AN AREA REMAIN OPEN WHEN THE AREA IS NOT ACTIVELY BEING WORKED) 6.IT IS REQUIRED THAT SOILS TRACKED FROM THE SITE BE CLEANED DAILY. 7.ALL REQUIREMENTS OF THE WATERSHED DISTRICT SHALL BE PER THE PERMIT. 8.ALL EROSION & SEDIMENT CONTROL MEASURES SHOWN ON THIS PLAN AND IMPLEMENTED IN THE FIELD AS DIRECTED BY THE ENGINEER SHALL CONFORM TO THE MPCA'S "PROTECTING WATER QUALITY IN URBAN AREAS: BEST MANAGEMENT PRACTICES FOR MINNESOTA". 9.ALL SOLID WASTE/CONSTRUCTION DEBRIS SHALL BE DISPOSED OF IN ACCORDANCE WITH MPCA REQUIREMENTS. HAZARDOUS MATERIALS SHALL BE STORED/DISPOSED OF IN COMPLIANCE WITH MPCA REGULATIONS 10.INLET SEDIMENTATION CONTROL IS TO BE PROVIDED TO ALL STORM SEWER CATCH BASINS. 11.CONTRACTOR SHALL PREVENT SOIL LOSS DURING CONSTRUCTION DUE TO WIND EROSION. 12.EMPLOY EROSION CONTROL BLANKET ON ANY NEW SLOPES STEEPER THAN 4 (H) TO 1 (V). EROSION & SEDIMENT CONTROL PLAN NOTES KEY NOTES INSTALL & MAINTAIN PERIMETER SILT FENCE, PER DETAIL INSTALL & MAINTAIN INLET SEDIMENT PROTECTION, PER DETAIL INSTALL TEMPORARY ROCK ENTRANCE AT CONSTRUCTION INGRESS & EGRESS LOCATION. HANDICAP PEDESTRIAN ROUTE: SURFACE GRADES SHALL NOT EXCEED 2.0% IN ANY DIRECTION. APPROXIMATE CONCRETE WASHOUT LOCATION, SEE DETAIL FOR MORE INFO INSTALL PERMANENT RIPRAP AT FES, PER DETAIL. EXTEND RIPRAP TO PERMANENT POND ELEVATION. INSTALL PERMANENT RIPRAP AND UNDERLAIN GEOTEXTILE FILTER FABRIC ON SLOPES STEEPER THAN 3:1, PER MnDOT SPECS SECTION 3601. 1 2 3 4 5 1 1 1 2 2 2 2 2 2 3 4 5 NEW EXPANDED INFILTRATION BASIN BOTTOM = 900.50 NWL = 901.30 HWL = 902.50 6 7 6 7 7 7 United States Department of Agriculture A product of the National Cooperative Soil Survey, a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local participants Custom Soil Resource Report for Washington County, Minnesota Natural Resources Conservation Service July 14, 2025 Preface Soil surveys contain information that affects land use planning in survey areas. They highlight soil limitations that affect various land uses and provide information about the properties of the soils in the survey areas. Soil surveys are designed for many different users, including farmers, ranchers, foresters, agronomists, urban planners, community officials, engineers, developers, builders, and home buyers. Also, conservationists, teachers, students, and specialists in recreation, waste disposal, and pollution control can use the surveys to help them understand, protect, or enhance the environment. Various land use regulations of Federal, State, and local governments may impose special restrictions on land use or land treatment. Soil surveys identify soil properties that are used in making various land use or land treatment decisions. The information is intended to help the land users identify and reduce the effects of soil limitations on various land uses. The landowner or user is responsible for identifying and complying with existing laws and regulations. Although soil survey information can be used for general farm, local, and wider area planning, onsite investigation is needed to supplement this information in some cases. Examples include soil quality assessments (http://www.nrcs.usda.gov/wps/ portal/nrcs/main/soils/health/) and certain conservation and engineering applications. For more detailed information, contact your local USDA Service Center (https://offices.sc.egov.usda.gov/locator/app?agency=nrcs) or your NRCS State Soil Scientist (http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/contactus/? cid=nrcs142p2_053951). Great differences in soil properties can occur within short distances. Some soils are seasonally wet or subject to flooding. Some are too unstable to be used as a foundation for buildings or roads. Clayey or wet soils are poorly suited to use as septic tank absorption fields. A high water table makes a soil poorly suited to basements or underground installations. The National Cooperative Soil Survey is a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local agencies. The Natural Resources Conservation Service (NRCS) has leadership for the Federal part of the National Cooperative Soil Survey. Information about soils is updated periodically. Updated information is available through the NRCS Web Soil Survey, the site for official soil survey information. The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or a part of an individual's income is derived from any public assistance program. (Not all prohibited bases apply to all programs.) Persons with disabilities who require 2 alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA's TARGET Center at (202) 720-2600 (voice and TDD). To file a complaint of discrimination, write to USDA, Director, Office of Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C. 20250-9410 or call (800) 795-3272 (voice) or (202) 720-6382 (TDD). USDA is an equal opportunity provider and employer. 3 Contents Preface....................................................................................................................2 How Soil Surveys Are Made..................................................................................5 Soil Map..................................................................................................................8 Soil Map................................................................................................................9 Legend................................................................................................................10 Map Unit Legend................................................................................................11 Map Unit Descriptions.........................................................................................11 Washington County, Minnesota......................................................................13 153B—Santiago silt loam, 2 to 6 percent slopes.........................................13 861C—Urban land-Kingsley complex, 3 to 15 percent slopes....................14 1039—Urban land.......................................................................................16 References............................................................................................................17 4 How Soil Surveys Are Made Soil surveys are made to provide information about the soils and miscellaneous areas in a specific area. They include a description of the soils and miscellaneous areas and their location on the landscape and tables that show soil properties and limitations affecting various uses. Soil scientists observed the steepness, length, and shape of the slopes; the general pattern of drainage; the kinds of crops and native plants; and the kinds of bedrock. They observed and described many soil profiles. A soil profile is the sequence of natural layers, or horizons, in a soil. The profile extends from the surface down into the unconsolidated material in which the soil formed or from the surface down to bedrock. The unconsolidated material is devoid of roots and other living organisms and has not been changed by other biological activity. Currently, soils are mapped according to the boundaries of major land resource areas (MLRAs). MLRAs are geographically associated land resource units that share common characteristics related to physiography, geology, climate, water resources, soils, biological resources, and land uses (USDA, 2006). Soil survey areas typically consist of parts of one or more MLRA. The soils and miscellaneous areas in a survey area occur in an orderly pattern that is related to the geology, landforms, relief, climate, and natural vegetation of the area. Each kind of soil and miscellaneous area is associated with a particular kind of landform or with a segment of the landform. By observing the soils and miscellaneous areas in the survey area and relating their position to specific segments of the landform, a soil scientist develops a concept, or model, of how they were formed. Thus, during mapping, this model enables the soil scientist to predict with a considerable degree of accuracy the kind of soil or miscellaneous area at a specific location on the landscape. Commonly, individual soils on the landscape merge into one another as their characteristics gradually change. To construct an accurate soil map, however, soil scientists must determine the boundaries between the soils. They can observe only a limited number of soil profiles. Nevertheless, these observations, supplemented by an understanding of the soil-vegetation-landscape relationship, are sufficient to verify predictions of the kinds of soil in an area and to determine the boundaries. Soil scientists recorded the characteristics of the soil profiles that they studied. They noted soil color, texture, size and shape of soil aggregates, kind and amount of rock fragments, distribution of plant roots, reaction, and other features that enable them to identify soils. After describing the soils in the survey area and determining their properties, the soil scientists assigned the soils to taxonomic classes (units). Taxonomic classes are concepts. Each taxonomic class has a set of soil characteristics with precisely defined limits. The classes are used as a basis for comparison to classify soils systematically. Soil taxonomy, the system of taxonomic classification used in the United States, is based mainly on the kind and character of soil properties and the arrangement of horizons within the profile. After the soil 5 scientists classified and named the soils in the survey area, they compared the individual soils with similar soils in the same taxonomic class in other areas so that they could confirm data and assemble additional data based on experience and research. The objective of soil mapping is not to delineate pure map unit components; the objective is to separate the landscape into landforms or landform segments that have similar use and management requirements. Each map unit is defined by a unique combination of soil components and/or miscellaneous areas in predictable proportions. Some components may be highly contrasting to the other components of the map unit. The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The delineation of such landforms and landform segments on the map provides sufficient information for the development of resource plans. If intensive use of small areas is planned, onsite investigation is needed to define and locate the soils and miscellaneous areas. Soil scientists make many field observations in the process of producing a soil map. The frequency of observation is dependent upon several factors, including scale of mapping, intensity of mapping, design of map units, complexity of the landscape, and experience of the soil scientist. Observations are made to test and refine the soil-landscape model and predictions and to verify the classification of the soils at specific locations. Once the soil-landscape model is refined, a significantly smaller number of measurements of individual soil properties are made and recorded. These measurements may include field measurements, such as those for color, depth to bedrock, and texture, and laboratory measurements, such as those for content of sand, silt, clay, salt, and other components. Properties of each soil typically vary from one point to another across the landscape. Observations for map unit components are aggregated to develop ranges of characteristics for the components. The aggregated values are presented. Direct measurements do not exist for every property presented for every map unit component. Values for some properties are estimated from combinations of other properties. While a soil survey is in progress, samples of some of the soils in the area generally are collected for laboratory analyses and for engineering tests. Soil scientists interpret the data from these analyses and tests as well as the field-observed characteristics and the soil properties to determine the expected behavior of the soils under different uses. Interpretations for all of the soils are field tested through observation of the soils in different uses and under different levels of management. Some interpretations are modified to fit local conditions, and some new interpretations are developed to meet local needs. Data are assembled from other sources, such as research information, production records, and field experience of specialists. For example, data on crop yields under defined levels of management are assembled from farm records and from field or plot experiments on the same kinds of soil. Predictions about soil behavior are based not only on soil properties but also on such variables as climate and biological activity. Soil conditions are predictable over long periods of time, but they are not predictable from year to year. For example, soil scientists can predict with a fairly high degree of accuracy that a given soil will have a high water table within certain depths in most years, but they cannot predict that a high water table will always be at a specific level in the soil on a specific date. After soil scientists located and identified the significant natural bodies of soil in the survey area, they drew the boundaries of these bodies on aerial photographs and Custom Soil Resource Report 6 identified each as a specific map unit. Aerial photographs show trees, buildings, fields, roads, and rivers, all of which help in locating boundaries accurately. Custom Soil Resource Report 7 Soil Map The soil map section includes the soil map for the defined area of interest, a list of soil map units on the map and extent of each map unit, and cartographic symbols displayed on the map. Also presented are various metadata about data used to produce the map, and a description of each soil map unit. 8 9 Custom Soil Resource Report Soil Map 49 8 6 6 8 0 49 8 6 7 0 0 49 8 6 7 2 0 49 8 6 7 4 0 49 8 6 7 6 0 49 8 6 7 8 0 49 8 6 8 0 0 49 8 6 8 2 0 49 8 6 8 4 0 49 8 6 8 6 0 49 8 6 8 8 0 49 8 6 9 0 0 49 8 6 6 8 0 49 8 6 7 0 0 49 8 6 7 2 0 49 8 6 7 4 0 49 8 6 7 6 0 49 8 6 7 8 0 49 8 6 8 0 0 49 8 6 8 2 0 49 8 6 8 4 0 49 8 6 8 6 0 49 8 6 8 8 0 49 8 6 9 0 0 515160 515180 515200 515220 515240 515260 515280 515300 515320 515160 515180 515200 515220 515240 515260 515280 515300 515320 45° 2' 7'' N 92 ° 4 8 ' 2 7 ' ' W 45° 2' 7'' N 92 ° 4 8 ' 1 9 ' ' W 45° 2' 0'' N 92 ° 4 8 ' 2 7 ' ' W 45° 2' 0'' N 92 ° 4 8 ' 1 9 ' ' W N Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 15N WGS84 0 50 100 200 300 Feet 0 15 30 60 90 Meters Map Scale: 1:1,110 if printed on A portrait (8.5" x 11") sheet. Soil Map may not be valid at this scale. MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Map Unit Polygons Soil Map Unit Lines Soil Map Unit Points Special Point Features Blowout Borrow Pit Clay Spot Closed Depression Gravel Pit Gravelly Spot Landfill Lava Flow Marsh or swamp Mine or Quarry Miscellaneous Water Perennial Water Rock Outcrop Saline Spot Sandy Spot Severely Eroded Spot Sinkhole Slide or Slip Sodic Spot Spoil Area Stony Spot Very Stony Spot Wet Spot Other Special Line Features Water Features Streams and Canals Transportation Rails Interstate Highways US Routes Major Roads Local Roads Background Aerial Photography The soil surveys that comprise your AOI were mapped at 1:15,800. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: Coordinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required. This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soil Survey Area: Washington County, Minnesota Survey Area Data: Version 20, Sep 7, 2024 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Jun 29, 2023—Sep 13, 2023 The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident. Custom Soil Resource Report 10 Map Unit Legend Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI 153B Santiago silt loam, 2 to 6 percent slopes 2.9 87.9% 861C Urban land-Kingsley complex, 3 to 15 percent slopes 0.2 7.3% 1039 Urban land 0.2 4.8% Totals for Area of Interest 3.3 100.0% Map Unit Descriptions The map units delineated on the detailed soil maps in a soil survey represent the soils or miscellaneous areas in the survey area. The map unit descriptions, along with the maps, can be used to determine the composition and properties of a unit. A map unit delineation on a soil map represents an area dominated by one or more major kinds of soil or miscellaneous areas. A map unit is identified and named according to the taxonomic classification of the dominant soils. Within a taxonomic class there are precisely defined limits for the properties of the soils. On the landscape, however, the soils are natural phenomena, and they have the characteristic variability of all natural phenomena. Thus, the range of some observed properties may extend beyond the limits defined for a taxonomic class. Areas of soils of a single taxonomic class rarely, if ever, can be mapped without including areas of other taxonomic classes. Consequently, every map unit is made up of the soils or miscellaneous areas for which it is named and some minor components that belong to taxonomic classes other than those of the major soils. Most minor soils have properties similar to those of the dominant soil or soils in the map unit, and thus they do not affect use and management. These are called noncontrasting, or similar, components. They may or may not be mentioned in a particular map unit description. Other minor components, however, have properties and behavioral characteristics divergent enough to affect use or to require different management. These are called contrasting, or dissimilar, components. They generally are in small areas and could not be mapped separately because of the scale used. Some small areas of strongly contrasting soils or miscellaneous areas are identified by a special symbol on the maps. If included in the database for a given area, the contrasting minor components are identified in the map unit descriptions along with some characteristics of each. A few areas of minor components may not have been observed, and consequently they are not mentioned in the descriptions, especially where the pattern was so complex that it was impractical to make enough observations to identify all the soils and miscellaneous areas on the landscape. The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The objective of mapping is not to delineate pure taxonomic classes but rather to separate the landscape into landforms or landform segments that have similar use and management requirements. The Custom Soil Resource Report 11 delineation of such segments on the map provides sufficient information for the development of resource plans. If intensive use of small areas is planned, however, onsite investigation is needed to define and locate the soils and miscellaneous areas. An identifying symbol precedes the map unit name in the map unit descriptions. Each description includes general facts about the unit and gives important soil properties and qualities. Soils that have profiles that are almost alike make up a soil series. Except for differences in texture of the surface layer, all the soils of a series have major horizons that are similar in composition, thickness, and arrangement. Soils of one series can differ in texture of the surface layer, slope, stoniness, salinity, degree of erosion, and other characteristics that affect their use. On the basis of such differences, a soil series is divided into soil phases. Most of the areas shown on the detailed soil maps are phases of soil series. The name of a soil phase commonly indicates a feature that affects use or management. For example, Alpha silt loam, 0 to 2 percent slopes, is a phase of the Alpha series. Some map units are made up of two or more major soils or miscellaneous areas. These map units are complexes, associations, or undifferentiated groups. A complex consists of two or more soils or miscellaneous areas in such an intricate pattern or in such small areas that they cannot be shown separately on the maps. The pattern and proportion of the soils or miscellaneous areas are somewhat similar in all areas. Alpha-Beta complex, 0 to 6 percent slopes, is an example. An association is made up of two or more geographically associated soils or miscellaneous areas that are shown as one unit on the maps. Because of present or anticipated uses of the map units in the survey area, it was not considered practical or necessary to map the soils or miscellaneous areas separately. The pattern and relative proportion of the soils or miscellaneous areas are somewhat similar. Alpha-Beta association, 0 to 2 percent slopes, is an example. An undifferentiated group is made up of two or more soils or miscellaneous areas that could be mapped individually but are mapped as one unit because similar interpretations can be made for use and management. The pattern and proportion of the soils or miscellaneous areas in a mapped area are not uniform. An area can be made up of only one of the major soils or miscellaneous areas, or it can be made up of all of them. Alpha and Beta soils, 0 to 2 percent slopes, is an example. Some surveys include miscellaneous areas. Such areas have little or no soil material and support little or no vegetation. Rock outcrop is an example. Custom Soil Resource Report 12 Washington County, Minnesota 153B—Santiago silt loam, 2 to 6 percent slopes Map Unit Setting National map unit symbol: 1t93t Elevation: 790 to 1,100 feet Mean annual precipitation: 28 to 36 inches Mean annual air temperature: 39 to 48 degrees F Frost-free period: 120 to 170 days Farmland classification: All areas are prime farmland Map Unit Composition Santiago and similar soils:90 percent Minor components:10 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Santiago Setting Landform:Moraines Landform position (two-dimensional):Backslope Down-slope shape:Linear Across-slope shape:Linear Parent material:Loess over till Typical profile Ap - 0 to 7 inches: silt loam E - 7 to 10 inches: silt loam Bt - 10 to 25 inches: silt loam 2Bt - 25 to 40 inches: sandy loam 2C - 40 to 60 inches: sandy loam Properties and qualities Slope:2 to 6 percent Depth to restrictive feature:More than 80 inches Drainage class:Well drained Capacity of the most limiting layer to transmit water (Ksat):Moderately low to moderately high (0.14 to 0.57 in/hr) Depth to water table:More than 80 inches Frequency of flooding:None Frequency of ponding:None Available water supply, 0 to 60 inches: High (about 10.2 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 2e Hydrologic Soil Group: B Ecological site: F090AY016WI - Loamy Upland Forage suitability group: Sloping Upland, Acid (G090XN006MN) Other vegetative classification: Sloping Upland, Acid (G090XN006MN) Hydric soil rating: No Custom Soil Resource Report 13 Minor Components Freeon Percent of map unit:5 percent Hydric soil rating: No Kingsley Percent of map unit:5 percent Hydric soil rating: No 861C—Urban land-Kingsley complex, 3 to 15 percent slopes Map Unit Setting National map unit symbol: 1t96l Elevation: 700 to 1,600 feet Mean annual precipitation: 28 to 36 inches Mean annual air temperature: 39 to 48 degrees F Frost-free period: 120 to 170 days Farmland classification: Not prime farmland Map Unit Composition Urban land:60 percent Kingsley and similar soils:35 percent Minor components:5 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Urban Land Setting Landform:Moraines Landform position (two-dimensional):Shoulder Down-slope shape:Linear Across-slope shape:Linear Interpretive groups Land capability classification (irrigated): None specified Forage suitability group: Not Suited (G090XN024MN) Other vegetative classification: Not Suited (G090XN024MN) Hydric soil rating: No Description of Kingsley Setting Landform:Moraines Landform position (two-dimensional):Shoulder Down-slope shape:Convex Across-slope shape:Convex Parent material:Till Typical profile Ap - 0 to 8 inches: sandy loam Custom Soil Resource Report 14 Bt - 8 to 39 inches: sandy loam C - 39 to 60 inches: sandy loam Properties and qualities Slope:3 to 15 percent Depth to restrictive feature:More than 80 inches Drainage class:Well drained Capacity of the most limiting layer to transmit water (Ksat):Moderately low to moderately high (0.14 to 0.57 in/hr) Depth to water table:More than 80 inches Frequency of flooding:None Frequency of ponding:None Available water supply, 0 to 60 inches: Moderate (about 8.5 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 3e Hydrologic Soil Group: C Ecological site: F090AY016WI - Loamy Upland Forage suitability group: Sloping Upland, Acid (G090XN006MN) Other vegetative classification: Sloping Upland, Acid (G090XN006MN) Hydric soil rating: No Minor Components Duluth Percent of map unit:2 percent Landform:Moraines Landform position (two-dimensional):Shoulder Down-slope shape:Convex Across-slope shape:Convex Ecological site:F090AY016WI - Loamy Upland Other vegetative classification:Sloping Upland, Acid (G090XN006MN) Hydric soil rating: No Prebish Percent of map unit:1 percent Landform:Depressions on moraines Down-slope shape:Concave Across-slope shape:Concave Ecological site:F090AY006WI - Wet Loamy Lowland Other vegetative classification:Ponded If Not Drained (G090XN013MN) Hydric soil rating: Yes Ronneby Percent of map unit:1 percent Landform:Drainageways on moraines Down-slope shape:Concave Across-slope shape:Linear Ecological site:F090AY011WI - Moist Loamy Lowland Other vegetative classification:Level Swale, Acid (G090XN005MN) Hydric soil rating: No Freer Percent of map unit:1 percent Landform:Moraines Down-slope shape:Linear Custom Soil Resource Report 15 Across-slope shape:Linear Ecological site:F090AY011WI - Moist Loamy Lowland Other vegetative classification:Level Swale, Acid (G090XN005MN) Hydric soil rating: No 1039—Urban land Map Unit Setting National map unit symbol: 1t96y Mean annual precipitation: 28 to 36 inches Mean annual air temperature: 39 to 48 degrees F Frost-free period: 120 to 170 days Farmland classification: Not prime farmland Map Unit Composition Urban land:100 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Urban Land Setting Landform:Moraines Down-slope shape:Linear Across-slope shape:Linear Interpretive groups Land capability classification (irrigated): None specified Forage suitability group: Not Suited (G090XN024MN) Other vegetative classification: Not Suited (G090XN024MN) Hydric soil rating: No Custom Soil Resource Report 16 References American Association of State Highway and Transportation Officials (AASHTO). 2004. Standard specifications for transportation materials and methods of sampling and testing. 24th edition. American Society for Testing and Materials (ASTM). 2005. Standard classification of soils for engineering purposes. ASTM Standard D2487-00. Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of wetlands and deep-water habitats of the United States. U.S. Fish and Wildlife Service FWS/OBS-79/31. Federal Register. July 13, 1994. Changes in hydric soils of the United States. Federal Register. September 18, 2002. Hydric soils of the United States. Hurt, G.W., and L.M. Vasilas, editors. Version 6.0, 2006. Field indicators of hydric soils in the United States. National Research Council. 1995. Wetlands: Characteristics and boundaries. Soil Survey Division Staff. 1993. Soil survey manual. Soil Conservation Service. U.S. Department of Agriculture Handbook 18. http://www.nrcs.usda.gov/wps/portal/ nrcs/detail/national/soils/?cid=nrcs142p2_054262 Soil Survey Staff. 1999. Soil taxonomy: A basic system of soil classification for making and interpreting soil surveys. 2nd edition. Natural Resources Conservation Service, U.S. Department of Agriculture Handbook 436. http:// www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053577 Soil Survey Staff. 2010. Keys to soil taxonomy. 11th edition. U.S. Department of Agriculture, Natural Resources Conservation Service. http:// www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053580 Tiner, R.W., Jr. 1985. Wetlands of Delaware. U.S. Fish and Wildlife Service and Delaware Department of Natural Resources and Environmental Control, Wetlands Section. United States Army Corps of Engineers, Environmental Laboratory. 1987. Corps of Engineers wetlands delineation manual. Waterways Experiment Station Technical Report Y-87-1. United States Department of Agriculture, Natural Resources Conservation Service. National forestry manual. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/ home/?cid=nrcs142p2_053374 United States Department of Agriculture, Natural Resources Conservation Service. National range and pasture handbook. http://www.nrcs.usda.gov/wps/portal/nrcs/ detail/national/landuse/rangepasture/?cid=stelprdb1043084 17 United States Department of Agriculture, Natural Resources Conservation Service. National soil survey handbook, title 430-VI. http://www.nrcs.usda.gov/wps/portal/ nrcs/detail/soils/scientists/?cid=nrcs142p2_054242 United States Department of Agriculture, Natural Resources Conservation Service. 2006. Land resource regions and major land resource areas of the United States, the Caribbean, and the Pacific Basin. U.S. Department of Agriculture Handbook 296. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/? cid=nrcs142p2_053624 United States Department of Agriculture, Soil Conservation Service. 1961. Land capability classification. U.S. Department of Agriculture Handbook 210. http:// www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_052290.pdf Custom Soil Resource Report 18 Page 1 of 3 5201 East River Road, Suite 303 Fridley, MN 55421 July 24, 2025 Drew Messmer Anderson 13605 – 1st Avenue North, Suite 100 Plymouth, MN 55441 RE: SAFL Baffle Sediment Removal for Central Automotive Mr. Messmer: This letter discusses the sediment (total suspended solids or TSS) removal efficiency for one proposed sump manhole with SAFL Baffle and SKUNK, at 14819 - 59th Street North in Oak Park Heights, Minnesota. The analysis was performed using SHSAM software by Barr Engineering. Recommended Sump Sizes The following tables provide the sediment removal efficiencies for various sump sizes at each structure. The recommended size is highlighted in yellow, and the sediment removal efficiency is 81.7%. This meets the project requirement of 80% TSS removal. The Utility Plan you provided is attached to this report, along with a detail that shows how the SAFL Baffle and SKUNK are installed in the structure. Structure ST-2 Sump Diameter (feet) Sump Depth (feet) Sediment Removal Efficiency (%) 4 4 76.9 5 5 81.7 6 3 78.3 6 6 85.1 8 6 87.6 10 6 89.3 Page 2 of 3 Inputs to SHSAM Software The SHSAM software used for this analysis was developed by Barr Engineering in Minneapolis and is based on data from several years of testing at the University of Minnesota’s St. Anthony Falls Laboratory. It is available free of charge at the following website: https://shsam.barr.com/ The inputs used for the analysis on this project are summarized in the following table: Structure Drain Area (acres) Percent Impervious Area Inlet Pipe Diameter (inches) Hydraulic Length (feet) Average Slope (%) Curve Number (pervious area) ST-2 0.3 95 12 160 0.32 61 The analysis used NOAA 15-minute precipitation files from a weather station in Golden Valley, Minnesota. The precipitation data was continuous from 1979 to 2013. Sediment concentration was set at 250 mg/L. Daily temperature information was taken from ae weather station in Northfield, Minnesota. SHSAM software uses a continuous rainfall model to calculate sediment removal efficiency for each storm event in the analysis period. It then calculates an average annual sediment removal efficiency over the entire period. Sediment removal efficiencies were calculated for a typical particle size distribution for sediment that typically accumulates on paved surfaces throughout the year. The average sediment removal for this particle size distribution is reported in the table at the bottom of Page 1. The sediment particle size distributions is shown below. Sediment Particle Size Distribution Page 3 of 3 Maintenance Maintenance of the SAFL Baffle consists of a visual inspection of the SAFL Baffle to ensure that no parts have become loose or damaged. Also, check the depth of sediment within the sump. If the top of the sediment is within 12 inches of the bottom of the SAFL Baffle, remove the sediment from the sump with a vacuum truck. Use the high-pressure washer on the vacuum truck to knock off any leaves or other debris that is stuck to the SAFL Baffle. The analysis for this site indicates that the sump will fill with sediment twice per year. Please call me at 651-237-5123 if you have any questions about these recommendations or how the analysis was performed. Sincerely, A.J. Schwidder, PE Upstream Technologies Inc.