Will monitor algae levels and fish population
Numerous reports of unusually thick green algae have prompted the Metropolitan Water Reclamation District of Greater Chicago (MWRD) to begin seasonal water quality and habitat testing on Peregrine Lake in Palatine.
MWRD owns a majority of the lake, and staff aquatic biologists began the testing earlier this month. They will return to the lake during the summer and fall to complete their analysis. The MWRD routinely monitors waterways such as small streams, creeks, rivers and the canals.
Among the specific water quality items the biologists will measure include temperature, dissolved oxygen and turbidity, or the water’s clarity. Like humans, aquatic organisms need oxygen to live. Depending on the type and location of the water body being assessed and the time of year, dissolved oxygen can differ greatly. Because cooler water can hold more oxygen, temperature affects dissolved oxygen concentrations, which ultimately affects the ability for aquatic life to survive.
Excess turbidity can be caused by erosion, silt, algae, storms and even from fish disturbing bottom sediments. Turbidity keeps light from penetrating the water so it affects aquatic plant growth. Different fish tolerate varying amounts of turbidity in the water. Some need clearer water to feed and reproduce, whereas others are able to tolerate more turbidity.
Residents are nervous about the algae ever since a major fish kill occurred in the lake in 2009. Excess algae in conjunction with less daylight during the winter months may have contributed to the fish kill by lowering dissolved oxygen levels in the water.
“It’s understandable to be concerned about the algae in Peregrine Lake and we want to ensure that all waterways remain healthy,” said Executive Director David St. Pierre. “We are conducting analyses throughout the year to monitor the lake and to educate residents how they can help to keep the water clean.”
Peregrine Lake freezes through almost every winter, and as a result, the fish population size naturally varies each year. But because the lake is shallow and un-shaded, conditions are good for algae growth.
Once testing and analysis is completed, the MWRD will use the information to better manage the algae and make recommendations to homeowners about how they can improve conditions and prevent further amounts of algae from growing.