Watershed district weighs an $875,897 alum treatment to cut Fish Lake algae
The Prior Lake-Spring Lake Watershed District board took up the Fish Lake Alum Treatment Project at its Tuesday, Sept. 15 meeting, with a public hearing and a vote on ordering the project on the agenda, according to the meeting materials. The project is estimated at $875,897 and is anticipated to reduce 659 lbs of phosphorus in the 171-acre lake, the internal loading that feeds its seasonal algae blooms. While Fish Lake is close to meeting state standards for recreational use, the materials say, elevated phosphorus is driving the nuisance algae.
The district applied for and received a BWSR Clean Water Fund grant of $796,270 for the project, with the remaining $79,630 coming from district alum reserves. The alum would go on the lake’s deeper sediments in a split-dose approach, with the first 50% dose in 2027, and a feasibility study puts the treatment’s longevity at about 44 years.
The treatment follows earlier district work on the lake, including the 200th Street Pond alum treatment and shoreline restoration projects.
What's next: The board's Sept. 15 minutes, approved at its next meeting, will record the vote on ordering the project. If ordered, bidding runs this fall and winter for a first dose in 2027.