Contact: Alexis Donath, 651-757-2312
St. Paul, Minn. — The Minnesota Pollution Control Agency (MPCA) is seeking feedback on a draft water quality improvement report for Cedar and McMahon lakes. The lakes are in Scott County, in the southern part of the Twin Cities metro area. The lakes were identified as impaired because they contain high levels of phosphorus. Though phosphorus occurs naturally, lakes with excess phosphorus are prone to frequent algal overgrowth. This interferes with swimming, fishing and recreation.
The MPCA determined that the largest sources of phosphorus in the two lakes are the release of phosphorus attached to sediment particles, decaying vegetation from invasive species like curlyleaf pondweed, and runoff from the lakes’ watersheds. In Cedar Lake, bottom-feeding carp also stir up sediment, releasing phosphorus into the water.
The draft report concludes that the phosphorus level of Cedar Lake must be reduced by 85 percent and that of McMahon Lake by 81 percent. These reductions will bring the lakes into compliance with state water quality standards.
The MPCA report, known as a "Total Maximum Daily Load" report, or TMDL, is part of a nationwide effort to clean up pollution in lakes and streams. Every two years, the MPCA compiles a list of lakes and streams that do not meet water quality standards and are considered impaired. The purpose of a TMDL report is to quantify pollutant levels in an impaired water body, identify sources of the pollution and propose ways to bring water quality to an acceptable level.
After reviewing comments from the public and obtaining approval from the U.S. Environmental Protection Agency, the MPCA and local organizations will work out a specific plan for improving water quality in Cedar and McMahon lakes.
The draft report may be viewed at www.pca.state.mn.us/veiz965. For more information or to submit comments, contact Chris Zadak (email Chris.Zadak@state.mn.us; phone 651-757-2837), MPCA, 520 Lafayette Rd. N., Saint Paul, MN 55155-4194
Comments must be received in writing at the MPCA office by July 20. They must include an explanation of the commenter’s interest in the TMDL report, a clear statement of any recommended changes (including references to specific sections of the TMDL), and specific reasons for any proposed changes. To learn more about impaired waters, visit the MPCA website at www.pca.state.mn.us/water/tmdl.
