Historic Lake Water Quality Monitoring and Lake Data
Contact: Sarah Holden 517-342-4083
Historically, EGLE and the Department of Natural Resources (DNR) monitored water quality in Michigan's lakes and streams. In 1973 the former DNR began systematically inventorying and sampling lakes to document trophic conditions as well as to obtain general baseline water quality information. In 1979, U.S. Environmental Protection Agency (EPA) funds were awarded to Michigan to expand the lakes monitoring effort and an ambient water quality monitoring program was initiated to sample and classify 729 public access lakes across the state. In 1998 with the support of Clean Michigan Initiative (CMI) funds the Lake Water Quality Assessment (LWQA) monitoring program was implemented in cooperation with the U.S. Geological Survey (USGS) - Michigan District as part of EGLE's Strategic Environmental Quality Monitoring Program for Michigan Surface Waters.
The LWQA monitoring program continued the ambient water quality monitoring effort initiated in 1979 for public access lakes across the state. The primary objectives of the LWQA monitoring program were:
- Determine the trophic conditions of the inland lakes in the state
- Identify waters that are high quality, as well as those that are not meeting water quality standards
- Determine whether inland lake water quality is changing with time
- Identify emerging problems through inland lake quality assessments
- Support EGLE watershed and lake management programs for protecting inland lake quality in the state
From 2001 - 2010, 866 lake basins from 729 public access lakes were monitored for baseline water-quality conditions and trophic status. Lake water quality assessment surveys were conducted during spring turnover and summer stratification periods. The surveys were coordinated with the EGLE's Water Resource Division's watershed permitting cycle. Water quality parameters monitored include nutrients (various forms of nitrogen and phosphorus), chlorophyll a, water clarity (Secchi depth), color, dissolved oxygen, water temperature, specific conductance, pH, alkalinity, hardness, and major ions such as calcium, magnesium, sodium and chloride. In about 75 percent of inland lake deep basins, trophic characteristics were associated with oligotrophic or mesotrophic conditions; 5 percent or less were categorized as hypereutrophic.
As part of the LWQA monitoring program, the USGS under the direction of EGLE used Landsat satellite imagery for the periods of 2003-2005 and 2007-2008 along with LWQA and CLMP water clarity data to develop an on-line application tool for predicting lake water clarity, chlorophyll content , and predict the trophic state of inland lakes greater than 20 acres in size. The LWQA monitoring program data are stored in the USGS National Water Information System (NWIS). The predicted water clarity of approximately 4000 inland lakes is now available on an interactive map on the USGS website.
Michigan Lakes: An Assessment of Water Quality (5-Year Cumulative Report)