Alexandria's Lake Agnes undergoes treatment to make it less green

Workers refill a pontoon with alum at Lake Agnes Park in Alexandria while treating the lake on Tuesday. The treatment is expected to conclude this week and one of the workers on scene said he could see the water getting more clear already.

By Al Edenloff

September 23, 2022 at 6:00 AM

ALEXANDRIA — Lake Agnes was bubbling with activity this week.

A big pontoon carrying 10 large cylinders cruised all around the lake on Sept. 19-23.

The goal: Reduce phosphorus levels on Lake Agnes and make it less green.

SOLlitude Lake Management, hired by the Alexandria Lake Area Sanitary District, treated the lake with a chemical compound, commonly referred to as alum.

This week’s work was the second alum treatment the lake has received in two years.

Back in 2020, ALASD accepted a $300,000 bid in 2020 to treat the lake with 129,424 gallons of alum in two applications.

The sanitary district is trying to reduce the amount of phosphorus, which spurs the growth of toxic algae. It’s exploring ways to remove invasive carp, which stir up phosphorus, and is using alum to bind to the phosphorus and sink it to the bottom of the lake.

Alum has been repeatedly shown to be safe for humans, according to ALASD, and it’s a common food additive that’s also been used for decades to clean drinking water.

Alum is also safe for fish and plants, according to ALASD. After it’s used, the fishery generally improves because the plants create habitat for fish, stabilize the lakebed, reduce shoreline, erosion, and help prevent the lake from returning to an algae-dominated state.

For more information, go to the website, www.alasdistrict.org and click on News.

Lake Agnes is 137 acres in size with a maximum depth of about 31 feet, according to the Douglas County Lake Association. It supports game fish, including pan fish, northern, largemouth bass, some smallmouth bass and walleye.

On its website , SOLitude Lake Management said it’s dedicated to "making water a more healthy and beautiful part of (the) world," and offers sustainable solutions that improve water quality and preserve natural resources.

SOLitude’s scientists, biologists, ecologists, and aquatic resource management professionals specialize in the development of customized lake, pond, wetland and fisheries management programs. This includes water quality testing and restoration, nutrient remediation, algae, and aquatic weed control, installation and maintenance of fountains and aeration systems, bathymetry, mechanical harvesting and hydro-raking, lake vegetation studies, biological assessments, habitat evaluations and invasive species management.

Pontoon treating Lake Agnes with alum — A pontoon operated by SOLitude Lake Management comes to shore to refill while applying alum on Lake Agnes in Alexandria Tuesday. Alum binds to phosphorus and sinks to the bottom to make the water cleaner. Lake Agnes was last treated with alum in 2020.

By Al Edenloff

Al Edenloff is the editor of the twice-weekly Echo Press. He started his journalism career when he was in 10th grade, writing football and basketball stories for the Parkers Prairie Independent.