Wassermann Lake Alum Treatment
Minnehaha Creek Watershed District (MCWD) conducted alum treatments of Wassermann Lake and Wassermann West Pond to significantly increase both the health and clarity of the lake. Both the lake and pond received two alum treatments. The first alum treatment was conducted on the West Pond, followed by a treatment of the lake and a second treatment of the pond in the spring of 2021. A second and final treatment on the lake occurred in the fall of 2022. The alum treatments increase the health of Wassermann Lake by reducing nutrient circulation and preventing frequent algae blooms.
Wassermann Lake’s water quality has been severely degraded by excessive nutrients both entering the lake and cycling internally within the lake. MCWD has been working in partnership with the City of Victoria and the Wassermann Lake Association to systematically solve these issues. Over the last five years, MCWD has completed multiple projects across the Six Mile Creek-Halsted Bay subwatershed to address the external sources of pollution to the lake.
After conducting the final alum treatment in the Fall 2022, MCWD continues to monitor Wassermann Lake’s water quality and vegetation response to determine the overall success of the treatment and what strategies might promote additional improvements to the lake.
2019 — MCWD determined in-lake management was the next step for the restoration of Wassermann Lake
January 2020 — MCWD awarded Clean Water Fund grant from BWSR
Summer 2020 — MCWD collected sediment cores and high-resolution dissolved oxygen data to shape a strategic/cost-effective application design
November 2020 — Virtual public meeting held to inform in-lake management strategy and set expectations around impacts and lake response
January 2021 — A multi-phased alum treatment applied to the deeper zones of the lake was determined as the best choice for in-lake management
May 2021 — Wassermann West Pond receives first alum treatment
May 2021 — Wassermann Lake received a successful first alum dose and Wassermann West Pond receives second dose.
Summer 2022 — Monitoring and analysis conducted to evaluate the lake’s response to the first alum dose and inform second dose application
September 2022 — Second alum treatment application completed
2023 — Water quality and vegetation monitored to evaluate lake response
2023 — Project completed
By the Numbers
phosphorus loading reduction annually
Applied across both the lake and pond
- Improved water quality in Wassermann Lake
- Improved aquatic vegetation and habitat
- Improved recreation opportunities
- Reduction in internal loading of phosphorus
- Continued partnership with the City of Victoria
MCWD has been working in partnership with the City of Victoria to improve water quality and facilitate development opportunities in the Six Mile Creek-Halsted Bay Subwatershed. Since 2017, MCWD has worked with the City of Victoria and the Wassermann Lake Association, completing multiple projects to address the external sources of pollution to Wasserman Lake.
Project Cost: $355,900
MCWD was awarded a highly competitive grant through the MN Board of Water and Soil Resources. The grant contributed $284,720 directly to two alum treatments in the Wassermann west pond and two treatments in Wassermann Lake proper. MCWD matched the grant with $71,180 to fund feasibility and design, as well as a portion of the treatment cost.