1100 MERRILL CREEK PKY 2025-07-28

' Current Conditions Summary Lot `L' is mostly barren with some light grass cover and some ponding water. An existing berm runs along the frontage of Merrill Creek Parkway on the north end of the site and is covered with young deciduous trees. Currently, stormwater from the property south of Lot `L' flows overland I and ponds in the south portion of Lot `L' and the north portion of Lot `K': See the.Existing Conditions Plan in Appendix A. Proposed Improvements Summary A 34,000-square-foot building is proposed for the site. Stormwater for the site will be collected ' in a conventional pipe system (see Sheet 2.0 in Appendix A). Stormwater quality treatment will be provided by a cartridge filter system (StormfilterTM). Detention for the site will be provided in the existing Associated Boulevard Detention Pond. Lot `L' was included in the tributary area for the design of the detention pond. A sedimentation pond will be constructed south of the site, and diversion swales will direct ' off-site water from undeveloped property to the south to the pond and prevent this off-site water from entering the site. The outfall from the sedimentation pond will run along the east property line and combine with flows from the Valley Electric site downstream of the proposed I StormfilterTM. The combined outfall will discharge to the Associated Boulevard Detention Pond (see Sheets C 1.1 and C2.0 in Appendix A). ' Conveyance Design The proposed storm drain system will convey surface runoff from the Valley Electric building ' roof,parking lots, sidewalks, and landscape areas. This storm drain system is designed to convey the 24-hour, 25-year storm event, which has a rainfall depth of 2.60 inches as defined in the COE Stormwater Management Manual. The rational method was used for pipe sizing calculations. A spreadsheet showing pipe size calculations is included in Appendix B. ' Basin Peak Flow North Parking Area 0.85 cfs West, South, and East Parking Areas 1.80 cfs ' Off-site Flows, Building Roof 23.64 cfs The pipes were sized to convey the 25-year runoff without exceeding 90 percent capacity. ' 8-inch and 12-inch pipe is adequate to convey the runoff from the parking lots,while a 24-inch line is required to convey off-site flows and the combined flows from the Valley Electric site to the detention pond. Valley Electric Building August 4,2003 Hydraulics Report -2- Revised August 20,2003 Reid iddleton