Agenda - Planning Commission - 05/01/2003

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the ponding system concept for storage during the large-scale event. Reference to Figure 6.6, however, shows that many additional smaller ponds exist on the site. Use of these ponds and consideration of the infiltration that naturally occurs through the sandy soils inherent to the site, yield a net reduction in flow leaving the site. Even further reduction can be made during the design and construction phases with the incorporation of additional BMPs. These features can also be used to filter inflow to the shallow groundwater system and replace some of the recharge lost to increased urbanization. The City can expect that volumes will be reduced if these features are incorporated in block design runoff routing. The largest benefit would likely accrue from installation associated with large parking lot surfaces. Further reductions can be explored during the detailed design phase. The final BMP element proposed for runoff control is the use of solids removal pre- treatment at storm sewer outfalls. These installations can be any of a wide var/ety of forebays or installed sumps/filters that remove particulates from stormwater prior to discharge into any of the drainageways throughout the site. These will also reduce overall pollutant removal and will be a major part of the city's Phase II list of available BMPs. As part of the design process for BMPs, replacement of non-native vegetation with native vegetation will occur whenever practicable and desirable. Phase I[ National Pollutant Discharge Elimination System (NPDES) permit The City of Ramsey has submitted its draft application for a Phase II National Pollutant Discharge Elimination System (NPDES) permit. The unsigned pmxnit was submitted on March 10, 2003 under the MPCA requirements for the program of the U.S. Environmental Protection Agency (EPA). MPCA extended the timeline for receipt of an officially signed permit so that the City could authorize signature through a City Council action. The new deadline for receipt of a signed application is May 9, 2003. After that, the City will need to adopt a Storm Water Pollution Prevention Program (SWPPP). Since the City owns and operates a municipal drainage system, it is 'subject to the provisions of the Municipal Separate Storm Sewer System (MS4) provisions of the law. Construction activities within the City, and specifically on the Ramsey Town Center site, are also subject to the Phase II General Storm Water Permit for Construction Activity. The MS4 program requires the City to develop and implement a Storm Water Pollution Prevention Program (SWPPP) that includes six minimum control measures: · Public education and outreach; · Public participation and involvement; · Illicit discharge, detection and elimination; · Construction site runoff control; · Post-construction site runoff control; and · Pollution prevention/good housekeeping. D- 13- 45