Troubled Waters: The Algae Crisis and Lake Menomin’s Future

The twenty-year journey to restoring Lake Menomin’s phosphorus targets has made minimal progress.

The intoxicating scent of sewage and thick mats of neon-green scum have become synonymous with Lake Menomin in recent summers. This annual blue-green algae crisis hasn’t just ruined the local tourism economy and closed the beloved Wakonda beach; it is a prominent symptom of Wisconsin’s Impaired Waters List epidemic. To save our local waterways, we must aggressively tackle the root cause by hitting the 40% phosphorus reduction targets outlined in the Wisconsin DNR’s 2012 TMDL.

While recent efforts have reduced phosphorus loads entering the Red Cedar River system by roughly 16%, this is not nearly enough to resolve the severe issues in Lake Menomin. To fundamentally improve water quality and combat toxic blue-green algae, experts emphasize that significantly larger reductions are required

By roughly 2006, Lake Menomin was formally designated as hypereutrophic due to excessive nutrient pollution and severe toxic algae blooms. While exact numbers shift based on weather and seasons, total phosphorus levels consistently spiked past the danger zone, averaging between 0.115 and 0.142 mg/L. Agricultural runoff and other non-point sources drive about 85% to 90% of this phosphorus influx, while city stormwater and wastewater plants contribute the remaining fraction.

In a watershed, point sources are specific, identifiable locations where pollutants are directly discharged into a waterway through a confined conveyance, such as a pipe or ditch. These sources are distinct, highly regulated, and mostly come from agriculture. What are non-point sources of runoff?

A nonpoint source of pollution in a watershed is a diffuse source of contamination that cannot be traced to a single, specific origin, like a discharge pipe. It is primarily caused by rainfall or snowmelt moving over and through the ground, picking up natural and man-made contaminants, and depositing them into local waterways.

How did the Red Cedar Watershed go from a wild rice bed to a hypereutrophic toxic lake?

The lake and the surrounding city of Menomonie are named after the Ojibwe word for “wild rice people” (Manoomini). Lake Menomin is a ~1,000-acre man-made reservoir on the Red Cedar River in Dunn County, Wisconsin. Originally a wild rice field, the basin was flooded in the late 1800s to create a mill pond and holding area for logs by the Knapp, Stout & Co. Lumber Company. The Red Cedar River was initially dammed in the mid-19th century. “The creek” and the original pond were major hubs for the white pine logging industry until the logging companies dissolved, shifting the area’s purpose toward generating electrical power and recreation. These dams created what is called an “impoundment.”

An impoundment on a watershed refers to any natural or human-made body of water—like a lake, reservoir, or pond—created by blocking, diverting, or retaining surface runoff. It is essentially a holding area designed to store water within a specific drainage basin, in this case, the Red Cedar Watershed via Lake Menomin.

Today, the 34-foot-deep Menomin Lake serves as a popular regional fishery for walleye, northern pike, and bass. However, the waterway suffers from hypereutrophic conditions. These high nutrient and phosphorus runoffs have heavily afflicted the lake during the summer months with recurring blue-green algae blooms, which historically have limited swimming and recreation.

Image credit: Red Cedar Flyfishing https://www.redcedarflyfishing.com/aboutus

The Red Cedar watershed in northwestern Wisconsin is an incredibly popular and highly regarded fishing destination.

These hypereutrophic conditions leave water bodies overloaded with nutrients like phosphorus and nitrogen, causing extreme biological productivity, which has destroyed the lake ecosystem. According to the Wisconsin Department of Natural Resources, Lake Menomin has been continuously listed on Wisconsin’s Impaired Waters list due to excessive phosphorus. There has been a plan in place to address these toxic blue-green algae blooms.

Are the Red Cedar Watershed’s high phosphorus levels just a regional concern? According to the WI DNR, nearly half of the state’s polluted waterways are impaired specifically due to excess phosphorus or related nutrients. In fact, total phosphorus consistently ranks as the primary culprit for new additions to Wisconsin’s Impaired Waters List.

Would removing the dams solve the problem?

According to the UW Madison article, “Deconstructing dams solves some problems, creates others,” No, removing a dam does not inherently solve high phosphorus levels. In fact, it often causes a temporary spike in downstream nutrient concentrations as trapped, nutrient-rich sediments are released. While dams slow the flow and trap phosphorus, removing them shifts the problem rather than eliminating the source.

Lake Menomin’s high phosphorus comes from non-point sources, primarily agricultural runoff, with a smaller percentage from point sources like wastewater treatment and urban stormwater. Are farmers working towards reducing their non-point runoff?

Farmer Initiatives Are Working, But the Red Cedar Watershed Needs You

Organizations such as the Red Cedar Conservation Farmers and the Farmers of Barron County Watersheds are leading these efforts. They promote conservation, offer cost-share programs for sustainable practices, and host educational field days. Through no-till or reduced-tillage methods and planting cover crops, local conservation groups report preventing thousands of pounds of phosphorus from reaching the watershed’s waterways annually. While these efforts have worked towards the solution, it is not enough. It will take a grassroots effort from the whole community living and working in the Red Cedar Watershed.

Saving Lake Menomin demands an ambitious (40\%) reduction in watershed phosphorus. While recent efforts have curbed some pollution, the roughly (16\%) drop achieved to date leaves local waterways severely impaired. To eliminate toxic blue-green algae and revive the local tourism economy, aggressive, fundamental action is essential

Sources

Source: https://dnr.wisconsin.gov/sites/default/files/topic/TMDLs/TainterMenomin_TMDLFinalReport.pdf

Source: https://fyi.extension.wisc.edu/redcedar/files/2017/08/rcphos.pdf

Source: https://exploremenomonie.com/history/

Source: https://news.wisc.edu/deconstructing-dams-solves-some-problems-creates-others/

Source: https://dunncountywi.gov/?SEC=%7B78511A11-F514-414A-A8B7-A6451B2F9687%7D

Source: https://www.menomonieminute.com/post/red-cedar-river-partnership-2023-annual-report-tells-of-the-year-s-accomplishments

Source: https://dunncountywi.gov/?SEC=%7B78511A11-F514-414A-A8B7-A6451B2F9687%7D

Rachel Tilseth is a Menomonie, Wisconsin-based environmental writer, filmmaker, and owner of Wolves of Douglas County WI Films & Media. Lead writer at The Red Cedar Watershed Ledger. Her work explores the intricate relationships between humans, wildlife, and local ecosystems.

Jan O’Neill-editor at large. Jan edits the blog for grammatical accuracy and contributes story ideas.

Given Jan’s extensive 45-year nursing background, protecting the health and well-being of the Menomonie area has been her life’s work. With deep local roots in the Red Cedar River Watershed, she views environmental conservation as a natural extension of public health. Jan is dedicated to halting the proposed mega data center to preserve the community’s natural resources, advocating instead for sustainable, community-driven economic development that protects the long-term quality of our watershed.

The Red Cedar Watershed Ledger is based in Menomonie, Wisconsin, in the historic Red Cedar Basin.

Discover how our local economy can thrive without leaving the planet behind. We cover news and stories on sustainable economic development, highlighting initiatives that boost community prosperity, foster equity, and protect our local ecosystems.

We are producing a series of educational articles and interviews featuring city leaders, scientists, and residents to explore sustainable economic development in the region. What began as a grassroots effort by Menomonie residents to successfully pause a controversial data center has evolved into a broader mission championing environmentally conscious, community-driven economic growth.”

The Red Cedar Watershed Ledger, Menomonie, WI

Wolves of Douglas CO WI Films & Media, LLC

https://wolvesofdouglascountywisconsin.com