CCP 02-19-2002 - Laserfiche WebLink

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Letter to Ms, lennifer Olson February 20, 2002 Page 2 of3 e Plan and the City's experience indicate that storm water pond construction and associated long-term maintenance costs are more cost effective that infiltration devices, Notwithstanding, the Plan has been amended (Section 2, Utilities, paragraph four, page 21 and Section 3, Regional Storm water Treatment Locations, paragraph two, page 24) recommending the use of alternative drainage systems and BMPs on a project by project basis, Section 3 - Hydraulic and Water Quality Analysis Preparation of a figure depicting water quality treatment in the City's subwatersheds is beyond the scope of the LSWMP preparation, We have amended Table 7 in the Plan identifying the completion of a subwatershed evaluation study as detailed information is lacking in the City (storm water routing, detention pond characteristics, etc.). Section 4 - Objectives and Policies The Wetland Conservation Act provision relating to storm water detention pond phosphorus removal efficiency and wetland mitigation/replacement has been added under the Ponds and Wetlands section of Objective F (page 33). Section 5 - Implementation Program e The City will keep RCWD informed on the feasibility and implementation of the storm water improvement projects identified in the LSWMP. Cost/Benefit for Pollutant Removal Table 9 did not include a column identifying pollutant removal capability for each practice because the information was not included in the referenced USEPA document. Similarly, the "Minnesota Urban Small Sites BMP Manual" does not include definitive BMP removal efficiencies. We agree that both infiltration devices and storm water ponds have demonstrated pollutant removal capabilities. However, the USEP A document (page 5-9) and the Center for Watershed Protection WEB sites (http://www,cwp,org/coJd- climates.htm and http://www.stormwatercenter.net/Librarv/PracticeArticles.htm) reference studies and cautionary statements on the long-term use and cost of infiltration systems. We have referenced the Minnesota BMP manual in the LSWMP (Section 3, Regional Storm water Treatment Locations, page 24) along with including it as a reference in Appendix M, As discussed earlier, the Water Quality Task Force Report recommendations will be implemented by the City where appropriate and in a cost-effective manner. The City will continue to use storm water ponds as the BMP of choice with other alternatives e