Wisconsin Natural Resources magazine

Wisconsin Natural Resources magazine

Pam McVety takes a water clarity measurement with a Secchi disc. © Bob Mcvety

Citizen Lake Monitoring Network volunteer Pam McVety takes a water clarity measurement with a Secchi disc.
© Bob Mcvety

June 2015

Dive into the Secchi Dip–In

Volunteers collaborate on North American Water Clarity Project.

Paul Skawinski

Across Wisconsin, citizen volunteers are recording water clarity data on hundreds of lakes and contributing to a project that tracks clarity trends on waterbodies across North America. These valuable volunteers are part of Wisconsin's Citizen Lake Monitoring Network, a collaboration between local lake organizations, the Department of Natural Resources and University of Wisconsin–Extension. Each year, CLMN volunteers participate in the North American Secchi Dip–In, a project that has been accumulating water clarity data since 1994.

In 2014, nearly 1,000 volunteers used simple devices known as Secchi discs to measure water clarity on Wisconsin lakes as part of the network. Since the network began in 1986 (then known as the Wisconsin Self–Help Lake Monitoring Program), volunteers have recorded 142,711 water clarity measurements on 1,370 lakes across the state.

More recently, the Department of Natural Resources has been using this on–the–ground monitoring data to calibrate instruments on a satellite known as the Landsat 8. With calibrated remote sensing, the department is able to estimate water clarity on thousands of unmonitored lakes throughout the state.

To make the calibration possible, DNR staff provides CLMN volunteers with a schedule of dates when the satellite will be flying over their lakes, and they are asked to record water clarity measurements on those dates. By measuring water clarity at the same time that the satellite is viewing their lake, a volunteer can assure the quality of the satellite's data.

DNR research scientist Steve Greb, who directs the satellite water quality monitoring activities, says this program would not be possible without the dedicated efforts of lake monitoring volunteers.

"The network has been critical to the success of our monitoring efforts," Greb says. "Our agency simply doesn't have the staff to sample hundreds of lakes on days when the satellite passes over. This collaborative effort is the first of its kind in the country. I get calls all the time from other state and federal agencies wanting to know more about our program and how they might initiate their own program."

In 2013, information from Landsat 8 allowed the Department of Natural Resources to estimate water clarity on more than 10,000 Wisconsin lakes.

Last year, 122 new volunteers joined CLMN to monitor water clarity, and additional volunteers signed up to monitor phosphorus and chlorophyll–A concentrations, water temperatures, aquatic invasive species, native aquatic plant populations and more.

CLMN is always looking for additional volunteers to become part of the network. Visit the CLMN website at uwsp.edu/uwexlakes/clmn to learn more about how you can get involved in this fun, free program.

Paul Skawinski works for the UW–Extension Lakes Program as the statewide coordinator of the Citizen Lake Monitoring Network.