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MR 1 - Full Stormwater Site Plan Narrative <br /> 1. Project Overview and Executive Summary <br /> The lot is 0.16 acres south of 63rd St SE. The lot is fairly flat with less than a <br /> 5% slope to the east that has been totally cleared in the past and has a berm <br /> that forces flow to the north to 63rd. The project scope is replacement of the <br /> existing driveway, and storage sheds that have been removed, with a new <br /> residence, and associated access drive and parking. The driveway will be in <br /> the same location and west of the existing driveway. The unmitigated area for <br /> the new impervious is 3,587 sf and the PGIS on-site is 680 Sf and a <br /> connection drive to the existing pavement of 353 Sf off-site for a total of 1,033 <br /> Sf. Given the small site and the lack of any soils that would accommodate <br /> infiltration, or any existing native growth on the site, The roof water is being <br /> routed to the street drainage system and the driveway is being dispersed. <br /> Water quality measures being proposed and identified in the Stormwater <br /> Pollution Prevention Plan (SWPPP). As a residential project it is exempt from <br /> meeting Minimum Requirement 3 (Source Control). BMP T5.12 will provide <br /> some treatment of the new/replaced parking. <br /> The site is a single drainage basin flowing to the east property line and then to <br /> the street to the north. All flow goes into the catch basin grate in front of the <br /> site. <br /> The sketch of the schematic drainage system design proposed for the <br /> development in the Appendix BMP T5.10C downspouts to a perforated <br /> connection to the street drainage system and sheetflow dispersion of the new <br /> parking to a 10' wide vegetated dispersion area. <br /> The upstream and downstream analysis show no key issues or limitations. <br /> No detention or retention sizing or storage volumes, nor conveyance sizing <br /> was required. <br /> Site planning does not require Minimum Requirement 6 (Runoff Treatment) as <br /> the PGIS area of 1,033 Sf is less than 5,000 Sf, Minimum Requirement 7 <br /> (Flow Control) as the overall impervious amount of 3,587 Sf is also less than <br /> 5,000 Sf, or Minimum Requirement 8 (Wetlands Protection) as no flows are <br /> being concentrated or diverted to or from any known wetlands <br /> Kravchuk Targeted Drainage Plan Page 3 <br />