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Voluteer Lake Monitoring Program

Illinois Volunteer Lake Monitoring Program

Secchi DiskThere are 3,041 lakes in Illinois and more than 87,000 ponds. In addition to being valuable recreational and ecological resources, these lakes serve as potable, industrial, and agricultural water supplies; as cooling water sources; and as flood control structures.

Lakes serve as traps for materials generated within their watersheds. The trapped material generally impairs water quality and may severely impact beneficial uses and significantly shorten the life of the lake. Suspended and deposited sediments can cause serious use impairment problems. Excessive aquatic macrophyte (plant) growth and/or algal blooms often result from the addition of nutrients such as nitrogen and phosphorus. An overabundance of plant life may tend to limit recreational and public water supply usage. Lakes may also collect heavy metal and organic contamination from urban, industrial, and agricultural sources. Dissolved oxygen deficiencies may limit biological habitat, or result in taste and odor problems for public water supplies.

Lakes are important resources that will continue to provide beneficial uses only if certain protective and educational steps are taken. In recognition of this need, the Volunteer Lake Monitoring Program (VLMP) was established in 1981 by the Illinois Environmental Protection Agency (EPA). The VLMP serves as an educational program for citizens to learn about lake ecosystems, as well as a cost-effective method of gathering fundamental information on Illinois inland lakes. The VLMP utilizes funds provided by the federal Clean Water Act and the state-funded Conservation 2000 Program to achieve the following objectives:

  • Increase citizen knowledge and awareness of the factors that affect lake quality so they can understand the lake/watershed/ecosystem and make informed decisions.

  • Encourage development and implementation of sound lake protection and management plans.

  • Develop local grass roots support for environmental programs and foster cooperation among citizens, organizations and various units of government.

  • Provide historic data to help document water quality impacts and support lake management decision-making.

  • Provide a guide for the implementation of lake protection/restoration and a framework for technical assistance for cooperative lake and watershed management projects.

Basic Monitoring

Zebra Mussel SamplerIn the Basic Monitoring Program, citizens select a lake in which they have an interest and are then trained to measure water clarity (transparency) using a Secchi disk. The disk consists of an eight-inch diameter, weighted metal plate painted black and white in alternate quadrants and attached to a calibrated rope. The disk is lowered into the lake water, and the depth at which it is no longer visible is noted. This measurement is called the Secchi disk transparency or the Secchi depth. The Secchi depth is used to document changes in the transparency of lake water. Typically, three sites are monitored on a lake, two times per month from May through October. The volunteer also records a series of field observations relating to other important environmental characteristics of the lake, such as water color, amount of aquatic plants present and site depth. Weather conditions on the day of sampling, as well as during the prior 48 hours, are reported. Recent lake management activities or other factors which could impact the lake are also documented. Along with the Secchi transparency monitoring, all volunteers are provided with a Zebra Mussel sampler. This sampler is placed in the lake near a high traffic area boat dock, a likely place for introduction of this exotic species. Volunteers inspect this sampler as well as the shoreline areas of the lake once a month for the presence of Zebra Mussels.

Expanded Monitoring

Chlorophyll SamplingAfter completing the Basic Monitoring Program for at least one year, volunteers enter a rotation which allows them to collect more detailed information on their lake. Participants in the Expanded Monitoring Program collect water samples monthly. One collection is made from one foot below the surface of the water. This sample is analyzed for ammonia, nitrates, total phosphorus, total suspended solids and volatile suspended solids. Another water sample is collected at twice the Secchi depth. This sample is filtered by the volunteer and analyzed for chlorophyll. Both the water sample and the chlorophyll filter are shipped to Illinois EPA's Champaign Laboratory for analysis. All analysis is done free of charge to the volunteer.


For further information about the program, contact the Division of Water Pollution Control-Lakes Unit at 217/782-3362 or the Illinois EPA Office of Public Information at 217/782-3397.
Illinois Volunteer Lake Monitoring Program

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