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Why Wild Rivers Conservancy Opposes the Proposed Lake Mallalieu Drawdown

07/01/202607/02/2026

Topic: Protect, Water

Wild Rivers Conservancy’s mission is to inspire stewardship to forever ensure the rare ecological integrity of the St. Croix and Namekagon Riverway. Every decision we make and every issue we engage in is guided by that mission.

It is why we oppose the proposed 7.5-foot drawdown of Lake Mallalieu. The Lake Mallalieu Association has proposed lowering the lake from September through next spring to address sediment accumulation that it says has reduced recreational opportunities and degraded fish habitat. However, releasing sediment and phosphorus into the St. Croix River would fuel harmful algal blooms, degrade aquatic habitat, and undermine decades of investment in restoring and protecting Lake St. Croix.

The St. Croix River is one of America’s original National Scenic Riverways and one of the cleanest, most ecologically significant rivers in the Upper Midwest. Protecting its exceptional water quality, diverse fish and wildlife habitat, and outstanding recreational opportunities requires careful planning and decision making throughout the entire St. Croix Watershed.

After reviewing the available scientific information and project materials, we believe the proposed drawdown presents unacceptable risks to Lake St. Croix and establishes a troubling precedent for the management of this nationally significant river.

Our opposition is based on three key concerns.

1. The Drawdown Would Increase Pollution in an Already Impaired Lake

Lake Mallalieu drains directly to Lake St. Croix through the Hudson Lower Power Dam. Sediment and phosphorus mobilized during the drawdown will be carried directly downstream into a lake that is already impaired by excess phosphorus and sediment.

For more than a decade, communities throughout the watershed have worked to reduce phosphorus entering Lake St. Croix because it fuels harmful algae blooms, degrades aquatic habitat, and diminishes water quality.

While the precise amount of phosphorus that will be released is still under debate, even the lowest estimated phosphorus discharge will exceed the annual phosphorus discharge from the Hudson Wastewater Treatment Plant or any one of Wisconsin’s 24 other permitted point-source dischargers to the St. Croix River and Lake St. Croix.

This project will be the largest permitted point-source phosphorus discharge to the St. Croix River on record.

2. The Proposed Lake Mallalieu Drawdown Will Undermine Decades of Conservation Investment

Restoring Lake St. Croix has required years of collaboration among farmers, landowners, local governments, conservation organizations, and state agencies.

Since 2013, St. Croix County alone has invested more than $4.4 million in conservation practices to reduce phosphorus entering Lake St. Croix. The City of Hudson’s 2024 sewer utility expenses amounted to $3.1 million to reduce pollutant loading to the St. Croix. These investments have produced measurable improvements in water quality and represent years of thoughtful planning and decision making.

Authorizing a project that will reverse this progress is inconsistent with watershed-wide Lake St. Croix restoration efforts and wasteful of the public investments being made to advance them.

3. It Sets the Wrong Precedent for the St. Croix River

This decision is about more than Lake Mallalieu.

Wild Rivers Conservancy supports restoration projects that improve watershed health. We do not support projects that transfer pollution downstream into one of the nation’s premier river systems.

Approving this drawdown will establish a troubling precedent: allowing what could become the largest permitted point-source phosphorus discharge in the history of the St. Croix River into a waterbody that is already impaired and the focus of decades of restoration efforts.

The St. Croix River is a national treasure. It deserves the highest standard of stewardship and the most careful scientific review before decisions are made that could permanently affect its water quality.

Looking Ahead

Healthy rivers don’t happen by accident. They are protected through thoughtful science, responsible stewardship, and decisions that place long-term ecological health above short-term convenience.

Wild Rivers Conservancy will continue to advocate for solutions that improve water quality throughout the watershed while protecting the rare ecological integrity of the St. Croix and Namekagon Riverway for generations to come.

Make Your Voice Heard

On July 7, the St. Croix County Board of Supervisors will vote on whether to uphold or rescind approval of the proposed Lake Mallalieu drawdown.

If you believe the St. Croix River deserves the highest level of protection, we encourage you to contact the County Board of Supervisors and ask them to oppose the proposed drawdown.

jared.bell@sccwi.gov

dani.erickson@sccwi.gov

mitch.ruedebusch@sccwi.gov

daniel.schmit@sccwi.gov

kerry.reis@sccwi.gov

diana.delaney@sccwi.gov

denise.shirley-carter@sccwi.gov

dan.fosterling@sccwi.gov

bob.feidler@sccwi.gov

wayne.roen@sccwi.gov

scott.counter@sccwi.gov

daniel.hansen@sccwi.gov