07-22-1991 Council Packet - Laserfiche WebLink

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Conservation District (LMCD) should have the responsibility for carry'ng out the environmental protection management activities related to Lake Minnetonka. Environmental Protection Goal for Lake Minnetonka Lake Minnetonka mu»i continue to be an open, fresh water lake capable of supporting year-round recreational activities. Its waters should be as clear and free of pollutants as practical. TTie natural aging of the lake should be controlled to insure that Lake Minnetonka can continue to exist as an open water recreational lake into the foreseeable future. Algae and other vegetative growth in the lake should be balanced to provide adequate aquatic habitat and human enjoyment of the lake. Environmental Protection and Mana2enient Focus The prindpal foctis of this element in the overall management plan for Lake Minnetonka is water quality and wetland protection. Generally, the various bays of Lake Minnetonka have exhibited improved water quality since the diversion of wastewater treatment plant effluent out of the watershed of the lake. Measurements have demonstrated improved summer water quality conditions. The water quality in Lake Minnetonka, with some exceptions, is now considered adequate to support most recreational uses. The reason for the lack of improvement in some areas of the lake ts not known for certain, but water quality experts indicate that it is probably due to two things: high levels of nutrients and chemicals from non-point sources (sources that are widespread and cannot be traced to a specific location) within those portions of the watershed that flow directly into these areas of the lake; and, high levels of phosphorus in lake sediments. Runoff and Shoreland Protection A major threat to the water quality of the lake appears to be the quantity and quality of runoff from the development and redevelopment of lands within tne watershed of the lake. Urbanization and redevelopment add more impervious surfaces like building roofs, driveways, parking lots and roadways; which increase the volume and rate of runoff. Increased runoff collects and carries with it, more soil, more vegetative matter, and more of the chemicals and heavy metals that we use in daily life. Lake Minnetonka's water quality is particularly affected by the actions of 14 lakeshore communities, the Minnehaha Creek Watershed District (MCWD), and the Department of Natural Resources (DNR) in controlling development and redevelopment within their jurisdictions. To protect the lake, strict controls need to be imposed. Accordingly, this part of the I^ng-Term Management Plan for Lake Minnetonka advocates adoption of shoreland regulations using the State-Wide Standards for Management qf Shoreland Areas for controlling dc^’elopment, redevelopment and land uses within 1,000 feet of the lake (shorelands). While additional phosphorus (which is a major factor in vegetative growth) entering the lake may be unavoidable, there are measures that should be taken to better manage non-point pollution of the lake. But, they are beyond the control of the LMCD. They will require the concerted efforts of the cities and the MCWD to improve their non-point management techniques both in the shoreland areas and in the remainder of the lake basin. Some lakeshore cities have their historic central business district in the shoreland zone. There needs 7/11 Draft - 2