Work continues to improve water quality of Sibley, Mayo lakes
Nearly two years after learning that Sibley and Mayo lakes in the Pequot Lakes area were impaired, residents heard study results Monday, Aug. 4, as lake stewards continue work toward improving the lakes' health.
The two lakes are on the state's list of impaired waters because of high phosphorus levels. Lake stewards have been reviewing existing data to determine where pollution is coming from, and will develop a plan to reduce that pollution. The ultimate goal is to secure grant money for lakeshore owners to take steps to improve lake water quality.
About three dozen people showed up at the Pequot Lakes Library to hear study results and provide feedback. They learned the study is open for public comments. Others can view results and provide comments online at http://www.pca.state.mn.us/index.php/water/water-types-and-programs/minn....
Meghan Jacobson, lake scientist with Emmons & Olivier Resources of Oakdale, Minnesota, who is working for the Minnesota Pollution Control Agency (MPCA) on this study, said the goal is to determine how much pollutant needs to be reduced to make a lake or stream fishable, swimmable and usable. Sibley and Mayo lakes have too many nutrients and algae at times for such recreation, Jacobson said, noting too much phospohorus in lakes makes algae grow and water less clear. Extra phosphorous can come from several sources, including the natural landscape,
runoff from soil, livestock, humans, the atmosphere, curly leaf pondweed and disturbance of lake sediments from rough fish like carp or boats.
Those who studied the lakes looked at water quality data and trends over the years, fish data and land cover. The amount of land that drains to Sibley Lake, called a watershed, is large, which provides many chances for nutrients to get into the lake, Jacobson said.
"Water quality is actually really good for how big the Sibley Lake watershed is," she said.
Over the last 10 years Sibley Lake has averaged 33 parts per billion (ppb) for phosphorous, compared to regional goals of 30 ppb or less. Algae averaged 20 ppb in Sibley Lake, compared to regional goals of 9 ppb or less.
"In terms of the algae that we see, we're a lot higher than we'd like in terms of goals for the region," Jacobson said.
Regarding clarity, the goal is less than 2 meters, and Sibley Lake is at 1.5 meters (4-5 feet) for transparency.
Phosphorous is coming from the atmosphere, lake sediments and the watershed, Jacobson said, noting the goal is to reduce the phosphorus load by 23 percent.
To identify specific locations where phosphorus needs to be reduced in the watershed, the MPCA in leading the study used the meeting to ask for input from residents.
"We don't know where everything is in the watershed (that is contributing phosphorus to the lake). We give our best guess based on data that's available," Jacobson said, but "the best data comes from people living in the watershed."
Because Sibley Lake flows into Mayo Lake, the idea is to focus efforts on the upstream lake (Sibley) first.
"If we improve Sibley Lake, that's going to benefit (the water quality of) Mayo Lake," Jacobson said.
Mayo Lake averages 36 ppb for phosphorous, 18 ppb for algae and 2 meters for clarity. The lake needs a 25 percent reduction in the phosphorus load.
After learning about the study of the lakes, those present broke into two groups to discuss each lake and identify any areas of concern, any areas that are special or need special protection, and any possible solutions to fix problem areas or protect special areas.
"There's only so much money, so what we need to decide as a group is: Where do we want to focus the resources?" said Bonnie Finnerty, watershed project manager for the MPCA in Brainerd.