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IMO CONSULTING <br />GROUP <br />7. Soil borings were performed on February 23, 2023. The geotechnical report and the <br />boring logs are included as an appendix to this report. <br />Hydraulic Modeling: <br />1. The existing conditions were modeled in HydroCAD, with the property divided <br />into three distinct drainage areas: <br />a) The West Side Forest and Grass Area. <br />i. To the west of the parking lot is a grassy area that drains into a <br />wooded area before draining into the lake. <br />b) The West Side of the Parking Lot. <br />i. The bituminous parking lot is split roughly down the middle with <br />the midpoint of the center aisle of parking stalls acting as the <br />division. This drainage area, to the west of this boundary, <br />ultimately outflows via the boat launch ramp. <br />c) The East Side of the Parking Lot. <br />i. The drainage area to the south and east of the previously <br />described boundary, including the runoff from North Shore <br />Drive, outflows to the northeast. <br />Table 1: Existing Conditions <br />(Peak Flow and Runoff Volume Results) <br />1-YEAR <br />Peak Flow (CFS) <br />Runoff Volume (AC -FT) <br />Runoff Volume (Gal.) <br />6.130 <br />0.294 <br />95,800 <br />10-YEAR <br />Peak Flow (CFS) <br />Runoff Volume (AC -FT) <br />Runoff Volume (Gal.) <br />12.570 <br />0.618 <br />201,376 <br />100-YEAR <br />Peak Flow (CFS) <br />Runoff Volume (AC -FT) <br />Runoff Volume (Gal.) <br />23.880 <br />1.216 <br />396,235 <br />Note that the quantity shown in the Runoff Volume is discharged directly to the lake. <br />B. PROPOSED CONDITIONS <br />Improvements: <br />The proposed stormwater management improvement components of the project <br />consist of a combination of permeable pavement, sand filter trenches beneath the <br />permeable pavement, perforated pipe at the bottom of the sand filters, and swirl <br />concentrators. <br />1. The site design layout was completed by IMO Consulting Group in 2025. <br />2. Stormwater from the adjacent County Road will continue to contribute to the <br />overall runoff from the site and will be treated prior to being released to Lake <br />Minnetonka. Note that today this water discharges directly to the lake. <br />3. All site improvements are within the property boundary. <br />Norm Arm <br />Stormwater Management <br />2 <br />113 <br />