Minnesota Pollution Control Agency

Contact: Alexis Donath, 651-757-2312 Saint Paul, Minn. -- Rainstorms and summer heat typically make parts of Maplewood's Kohlman Lake succumb to green algae blooms in late summer. After working with consultants, stakeholders and citizen groups, the Minnesota Pollution Control Agency (MPCA) is seeking public comments on a Total Maximum Daily Load (TMDL) water quality report developed to help the struggling lake go from green to clean. The public notice period will run from Aug. 31 to Sept. 30, 2009. "We need some help from concerned citizens in order to have a positive impact on lake water quality," said Roger Ramthun, project manger with the MPCA. Kohlman Lake is the most upstream of the four lakes of the Lake Phalen Chain of Lakes covering parts of Maplewood and Saint Paul. The 74-acre lake has an average depth of about four feet. Shallow lakes are more susceptible to excessive phosphorus pollution, which can create the smelly green water caused by summer algae blooms. Such blooms are fueled in part by fertilizers and other nutrients that run off from lawns and gardens, either directly or by way of driveways, roads and street gutters that feed storm sewers which run to lakes or rivers. The Kohlman Lake report calls for a reduction in phosphorus levels by more than one-third. The phosphorus reduction plan is part of a nationwide TMDL effort under the federal Clean Water Act to identify and clean up pollution in streams, rivers and lakes. Kohlman Lake's June through September average phosphorus level from 1997-2006 was 50 percent above the phosphorus standard. A TMDL report is a scientific study that calculates the maximum amount of a pollutant a water body can receive ("loading capacity") without exceeding water quality standards. This TMDL report follows a strategic lake management plan completed for Kohlman Lake in 2004. Although phosphorus in modest amounts is beneficial to aquatic plant life, lakes in urban or agricultural areas frequently suffer from excessive nutrients as rainfall washes these nutrients into nearby lakes from sidewalks, streets, lawns or farmland. Pollution experts estimate that 70-percent of the phosphorus found in lakes comes from human activities. Lawn or garden fertilizer along with leaves and grass clippings are common sources of urban lake nutrient problems. Reducing phosphorus levels is a long process and dependent on citizen behavior change and cooperation of municipalities. Decreasing the use of fertilizers, creating buffer zones of native plants near the lake shore to absorb runoff, and sloping shorelines to reduce runoff into lakes are common practices to cut phosphorus levels in lakes. Homeowners can also help by staying in the habit of keeping grass clippings and leaves off sidewalks and streets - so rainstorms can't wash the clippings into rivers and lakes via storm sewers. The Ramsey Washington Metro Watershed District Enhanced has already installed enhanced sand filters and permeable limestone barriers to remove phosphorus from water coming in to Kohlman Lake. Other planned actions will include reducing the amount of impervious surfaces to reduce runoff, and increasing permeable pavement and boulevard expansions with infiltration that can absorb more runoff before it reaches the street. The Kohlman Lake TMDL plan is available on the Web at www.pca.state.mn.us/water/tmdl/tmdl-draft.html or at the MPCA St. Paul office at 520 Lafayette Road North. Comments must be submitted by Sept. 30, 2009, to Roger Ramthun, MPCA, 520 Lafayette Road North, St. Paul, MN 55155, or by phone at 651-757-2663. 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/index.html, or toll-free at 1-800-657-3864.