The third and final dose of the alum treatment on Spring Lake is set to begin Monday, May 4. The treatment should take 10-14 days to complete, depending on weather conditions as the contractor cannot apply the alum if it is too windy. The project will be staged at the Spring Lake boat launch. The launch will remain open for public use.
Treatment on Upper Prior is currently scheduled to begin on May 26 and should take 8-11 days to complete. This is the first time Upper Prior Lake has been treated with alum! The treatment schedule is still dependent on some grant approvals so the start date is subject to change. The treatment is largely funded by a grant from the Minnesota Board of Soil & Water Resources (BWSR). The project will likely be staged at the Dewitt boat launch which will remain open to the public. However, we are looking into a couple other potential locations for staging.
Aluminum sulfate (alum) binds with the phosphorus, inactivating it and making it unavailable for algae to use. Less algae is not only visually more appealing and better for recreation, it allows more sunlight to reach the lake bottom which is beneficial for aquatic plants and fish. Find out more here.
What else is there to know? Boating, swimming, fishing, and eating the fish you catch during the treatment is fine. The water is safe for dogs to drink and play in as well.
Please avoid getting in the way of the barge. The barge follows computerized tracks and is programmed to apply specific doses of alum to the different locations in the lake. If you are on the lake and see the barge headed your way, please help us out and move out of the barge’s way. The water will appear temporarily cloudy after the alum is applied (see photo above), this is normal and the water will clear up as the alum settles to the bottom.
Alum treatments are just one of many ways the District is working to improve the water quality in our lakes. Find more information on our website here.