02-24-2009 Council Work Session Packet

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CMP Part 3B. Land Use Plan _ water nutrient pollution. This spiral effect results in statistically even greater levels of pollution than the original sewage "problem" might have been. For example, Eugene Hickok's 1973 Storm Water Impact Statement which ��es identified up to ten times more phosphorus alone from urban storm water runoff than from Orono's existing rural land use at that time. One need only to look to the case example of Lake Calhoun in Minneapolis. There has never been a drop of sewage effluent running into Calhoun, but the lake in past decades suffered severe pollution from high levels of nutrients contained in the storm water runoff from the densely developed watershed. Storm water nutrient pollution from the urban runoff overwhelmed the natural life system of the lake and resulted in accelerated eutrophication. The cost of solving this problem, either filtering or rerouting the storm water, has consistently been judged too expensive for Calhoun. The cost of the same solutions on the 50 times larger Minnetonka is inconceivable. Thus the recommendation of many studies as already incorporated in MPCA and MnDNR policy is that lakeshore density be limited and that the natural system of wetlands and marshes be forever protected and preserved as the only practical, economic method of filtering nutrients from storm water runoff. In response to the above concerns, Orono in the 1970's became a nationally recognized leader in espousing environmental protection. Land use planning since the 1950's has stressed the environmental advantages of low density development. Long before the Minnesota Wetland Conservation Act (WCA) was passed, �shorelands, wetlands and natural drainage systems were preserved in Orono by tradition and by ordinance. Orono's 2008-2030 Land Use Plan will continue this tradition and this commitment. While Orono's Surface Water Management Plan originally adopted in December 2002 places a significant emphasis on preservation of wetlands, it also provides for the establishment of supplementary stormwater management ponds and Best Management Practices (BMPs� to help counteract the impacts of development within the watershed. The City of Orono has adopted the use of NURP (National Urban Runoff Program) standards for the design of man-made supplementary stormwater ponds. The City has been requiring NURP ponds for stormwater management within new developments in accordance with standards of the Minnehaha Creek Watershed District. NURP pond design criteria per the "Walker Model" are primarily based on the removal of suspended particles such as sand, silt, etc. Secondary design criteria enhance the capability of NURP ponds to remove other pollutants such as trace metals, hydrocarbons, nutrients (such as phosphorus) and pesticides. Phosphorus is mainly removed through biological uptake in algae and aquatic plants. When the algae die, the nutrients fall to the bottom of the pond and become part of the sediments. City of Orono Community Management Plan 2008-2030 Page 3B-5