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Memo Bon«streo <br />RoMne <br />AndertOc& <br />Associates <br />IAglri#«rt 4 A4^t*cti <br />4. Excavation of temporary sedimentation ponds and the use of BMPs should be in place during each lot <br />construction to reduce the erosion to the adjacent wetland. <br />Water Quantity <br />The topography of this site prevents the entire site to drain to a single ponding area. We offer the following <br />recommendations: <br />1. It is recommended that the Impervious surfaces, (house, driveway, and yard) and any land disturbed <br />during construction be routed to drain into the street and Into the proposed ponding area. This will <br />reduce the amount of untreated runoff draining directly to the adjacent wetland. <br />2. The 100-year HWL for the proposed pond does not seem to provide sufficient freeboard for Willow <br />Road. The elevation of the low point on Willow Road should bo established and submitted to city staff. <br />3. The covor for the outlet structure under Willow Road should be evaluated. <br />4. It is difficult to determine from the grading plan whether a maintenance bench above the pond NWL is <br />being provided. At a minimum there should be one provided around Inlets, outlets, and at any point <br />where dredging operations might occur. <br />5. The ponding area should also have a 10:1 aquatic bench at the ponds NWL. The ponding area <br />illustrated on the plans does not appear to have this feature. <br />6. The installation of an Emergency Over Flow (E.O.F.) is recommended for this pond. The E.O.F. <br />should provide overland drainage for the pond during storms that exceed the 100-year event, and or <br />when the outlet structure becomes obstructed. The EOF should protect adjacent homes and roadways. <br />Bon0»troo, Anderllk and Assoclatea <br />2335 West Highway 36 » St. Paul. MN 55113 « Phone: 651-636-4600 » Fax: 651-636-1311