The Macatawa Watershed includes 175 square miles of land that drains to Lake Macatawa. Lake Macatawa’s water quality is impaired because too much sediment and phosphorus enters the lake. Rain water washes sediment and phosphorus off the land and into the lake through streams and the storm sewer system. Once in the lake, sediment can smother fish habitat and phosphorus can encourage algae and other plants to grow. This can lead to other problems that limits the lake’s ability to support healthy fish populations.
The MACC has worked with local units of government and other community partners since 1996 to reduce sediment and phosphorus inputs to the lake. In 1999, the US Environmental Protection Agency approved a total maximum daily load (TMDL) for phosphorus in Lake Macatawa. This document established a maximum amount of phosphorus that the lake can receive each year and still meet water quality standards that support fish and other aquatic life. In 2000, the MACC and community stakeholders signed a voluntary agreement with the Michigan Department of Environmental Quality (DEQ) to reduce phosphorus in the lake. The agreement was re-signed in 2010. The Macatawa Watershed Management Plan recommends actions that can reduce phosphorus. These actions include public education, policy changes and best management practices to prevent rain from washing away sediment and phosphorus. The MACC tracks and reports activities that result in phosphorus reductions. The 2017 TMDL annual report to the Michigan DEQ is available in the documents below (previous reports will be provided upon request).
The TMDL recommends reducing annual phosphorus loads to the lake to no more than 55,000 pounds per year or an average concentration in the lake of 50 parts per billion. Since it is difficult to measure how much phosphorus actually enters the lake each year, we monitor the concentration of phosphorus in the lake to measure progress toward meeting this goal. Recent monitoring reports are available here.