Contact: Anne Moore, 218-302-6605
St. Paul, Minn. -- The Minnesota Pollution Control Agency (MPCA) is seeking comments on a draft water quality improvement report for four lakes west of the Twin Cities. Concurrently, additional comments are being requested for a site-specific standard for one of the listed lakes. The public comment period begins Sept. 27 and continues through Oct. 27, 2010.
The Minnehaha Creek Watershed Lakes Excess Nutrients Total Maximum Daily Load (TMDL) report covers Lake Nokomis in Hennepin County and Parley Lake, Lake Virginia and Wasserman Lake in Carver County. All of the lakes and their watersheds are located within the Minnehaha Creek Watershed District in the Twin Cities metropolitan area.
The lakes have been placed on the state's impaired waters list because of excess nutrient levels, particularly phosphorus. While phosphorus is an essential nutrient for algae and plants, it is considered a pollutant when it stimulates excessive algae growth. The TMDL studies assessed the phosphorus concentration in the lakes and indicated that a phosphorus reduction from 20 to 62 percent in the Carver County lakes will be needed to meet state water quality standards during summer growing season conditions. The Hennepin County lake’s reductions are 57 percent to meet state standards and 35 percent to meet the site-specific standard.
The additional proposal to use a site-specific water quality standard for Lake Nokomis, rather than the state water quality standard for deep lakes, is based on a detailed analysis of the lake’s characteristics and multiple years of in-lake water quality data. Nokomis narrowly misses the state’s definition of a shallow lake, which would have a less stringent state water quality standard, but does function ecologically much like one. Therefore, the proposal to use a hybrid of deep and shallow standards is expected to achieve the needed level of water quality for recreational use.
The TMDL report was prepared as part of a nationwide effort under the federal Clean Water Act to identify and clean up pollution in streams, rivers and lakes. Every two years, states are required to submit a list of impaired waters to the U.S. Environmental Protection Agency (EPA). A TMDL report is a scientific study that calculates the maximum amount of a pollutant a water body can receive, known as the “loading capacity,” without exceeding water quality standards.
After receiving public comments, the MPCA will revise the draft TMDL report and submit it to the EPA for approval. Following approval, plans will be developed to reduce phosphorus pollution in the lakes. The Minnehaha Creek Watershed District Lakes Excess Nutrients Total Maximum Daily Load draft report is available on the Web at www.pca.state.mn.us/water/tmdl/tmdl-draft.html and at the MPCA’s St. Paul office, 520 Lafayette Road North. Comments may be submitted to Chris Zadak, MPCA, 520 Lafayette Road North, St. Paul, MN 55155. For more information, contact Zadak at 651-757-2837, 1-800-657-3864 or via e-mail at chris.zadak@state.mn.us.
Written comments must include the following:
1. A statement of your interest in the draft TMDL report;
2. A statement of the action you wish the MPCA to take, including specific references to sections of the draft TMDL that you believe should be changed; and
3. Specific reasons supporting your position.
More information on the state's impaired waters list and TMDL studies is available on the Web at www.pca.state.mn.us/water/tmdl or toll-free at 1-800-657-3864.
