Como Lake Alum and Herbicide Treatments
Capitol Region Watershed District (CRWD) is committed to improving water quality in Como Lake, a beloved water resource in Saint Paul for over a century. Despite efforts to address the water quality in the lake over the years, decades of stormwater runoff and pollution have made a new Como Lake plan necessary.
The 70 acre Como Lake drains more than 1,711 acres of land in Saint Paul, Roseville, and Falcon Heights. With a maximum depth of 15.5 feet, it is a shallow body of water. The shallow depth, coupled with significant nutrient and pollution in stormwater runoff, has had a significant impact on Como Lake water quality. In fact, CRWD began when a group of residents raised concerns about the water quality in Como Lake. Accordingly, the District has placed a high priority on improving Como Lake, as it is one of the most recognizable and well-loved water resources.
Spring 2020 Lake Improvement Projects
- Alum (aluminum sulfate) was applied to Como Lake this spring to reduce phosphorus being recycled inside of the lake.
- The treatment is expected to dramatically reduce algae growth and improve water clarity and quality.
- Alum is commonly used in drinking water treatment and has been a safe lake management tool for decades.
View Alum Treatment Factsheet
View Alum Treatment Updates blog post
- The herbicide Fluridone was applied to Como Lake this spring to target the overgrowth of an unwanted invasive aquatic plant called curly-leaf pondweed.
- Many studies have shown that herbicide treatments are the most effective solution for reducing curly-leaf pondweed, and similar treatments have been successfully used on a number of metro area lakes in the past decade.
- Controlling curly-leaf pondweed is critical for improving water quality in Como Lake.
View Herbicide Factsheet
View Herbicide Treatment Updates blog post