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LARKIN, HOFFMAN, DALY & LINDGREN, LTD. Mr. Steven R. Sarkozy Thomas M. Scott, Esq. May 28, 1999 Page 12 basin will be conveyed by a new system of catch basins and pipes to a wet detention basin to be located at the southeast corner of the parking lot. The proposed stonnwater system and new wet pond will dramatically reduce (about 50%) peak discharges from the site for the one-year and 1 DO-year storm events. The table below compares the new proposed (post-development) system to the existing (pre-development) system: Table 1: Comparison of Post-Development Stormwater Condition to Pre-Development Stormwater Condition One- Year Storm 1 00- Year Storm Development Peak Discharge Max Storage Peak Discharge Max Storage Condition (CFS) Volume (CF) (CFS) Volume (CF) Pre-Development 14.9 4,451 60.7 7,551 Post-Development 7.9 11,788 33.6 31,163 The proposed Cub Foods project will not affect an existing stonnwater overflow at Shryer Avenue. Currently, if stonnwater were to pond in Shryer Avenue, water is able'to be released from Shryer via an overland overflow route which conveys the stonnwater along a depressed walkway and into the mall parking lot. This overflow will be maintained with the Cub Foods project. Once in the mall parking lot area, the overflow stonnwater, if any, will be conveyed to the new detention basin where it will be treated. The proposed Cub Foods project will significantly improve water quality treatment as compared to existing conditions. The new southeast pond will be designed to National Urban Runoff Program (''N.U.R.P.'') and Rice Creek Watershed District standards and will provide live storage for the 1 DO-year stonn event. In addition, the Cub Foods project incorporates various infiltration practices recommended by Rice Creek Watershed District that will actually reduce the volume of stonnwater which leaves the site for a given storm event. These infiltration practices include depressional storage and vegetated swales. The reduction in runoff volume combined with the approximate 50% reduction in peak flows will dramatically reduce downstream flooding potential.