On July 23, 2022, I helped report a massive fish kill on Rush Creek, one of my favorite local trout streams just three miles south of town. The massive die-off was the third one within a seven-year period, all within a 13-mile radius of my town.  And it wasn’t just the number of fish, but the size. A landowner along that stretch of Rush Creek became sick when he found and photographed a dead 27-inch brown trout, the fish of a lifetime. It could take a decade for that part of Rush Creek to produce a fish of that size again. Rush Creek winds through large corn and soybean fields and the fish kill was clearly linked to a combination of manure run-off and aerial fungicide spraying hours before that large rainfall event.

-Mark Reisetter, MNTU Member

Today, January 28, 2025, Minnesota Trout Unlimited joined the Minnesota Center for Environmental Advocacy (MCEA) and the Minnesota Well Owners Association (MNWOO) in a lawsuit against the Minnesota Pollution Control Agency and Minnesota Department of Agriculture to compel them to do a better job of protecting coldwater ecosystems from harm caused by high nitrate levels and fish kills. Current state rules governing fertilizer application and manure management are not working well enough to prevent serious harm to trout streams and trout anglers.

Why is MNTU joining this lawsuit?

Minnesota Trout Unlimited’s mission is to protect, restore, and sustain Minnesota’s coldwater fisheries and the watersheds and groundwater sources that support them. MNTU is joining this lawsuit to protect coldwater fisheries and trout anglers from the harm being caused by excessive nitrogen and manure applications in these watersheds. In April 2023 MNTU joined partners in petitioning the EPA to use its authority to require three state agencies to do more to halt and reverse the worsening nitrate contamination levels in southeast Minnesota. The EPA agreed with us and required the state agencies to develop a work plan outlining “timely actions to address the nitrate contamination.”

In January 2024 the agencies, including the Minnesota Pollution Control Agency (MPCA) and Minnesota Department of Agriculture (MDA), produced a work plan. Although the work plan promises some steps that might improve the situation, it does not go far enough, fast enough. Representative Rick Hansen, longtime member and Chair of the House Environment committee, called the plan “embarrassing” and not the response that is needed to respond to crisis we are currently in.  Because the EPA under the new administration is unlikely to put pressure on the MPCA and MDA to do more, we must turn to state law to force these two agencies to do better.

What is the goal of the lawsuit?

The goal of the state lawsuit is to force MPCA and MDA into rulemaking procedures that will tighten regulations on manure and commercial fertilizer applications. We are not seeking to punish anyone, rather to get the public rulemaking processes started. It is important to note that farmers will have a voice in how the rules are revised to ensure they can operate profitably while protecting water quality. They have been told that the current rules work to protect public waters and well water, when in fact they do not.  Farmers care about clean water too. They deserve the better information and guidance that rulemaking will produce. 

The threat of nitrates to coldwater fisheries

The nitrogen cycle is complex and results in various compounds, including nitrate and ammonia.  Nitrate is the predominant form of nitrogen in surface waters in the karst region and is frequently found in concentrations that harm aquatic life (i.e., above 5 mg/liter). The ammonia in fertilizer (ammonium nitrate) is more toxic than nitrate. Elevated ammonia levels have been detected in some of the recent fish kills (e.g., Garvin Brook in 2019), indicating that manure applications are a cause of the fish kills. 

• The MPCA reviewed the results of 110 scientific studies and determined that nitrate concentrations above 5 mg/liter harm aquatic insects and other aquatic life.  While the MPCA failed to formally adopt this limit as a water quality standard, it admits that concentrations above 5 mg/liter are harming our trout streams.
• When manure is washed into streams and tributaries it can kill fish (and other aquatic life) because of potentially high concentrations of ammonia which rob the water of dissolved oxygen.  Trout have high oxygen needs and fish kills occur when elevated ammonia levels rapidly deplete the oxygen.
• The toxicity of ammonia in manure depends upon the pH of the manure and the water temperature, pH and dissolved oxygen levels of the receiving stream. The pH of the manure can change the water pH, shocking the fish fatally. Additionally, a direct shock of ammonia can fatally burn the gills and respiratory systems of fish.

The legal foundation

Minnesota Environmental Rights Act lays the foundation for this lawsuit. Governor Wendell Anderson signed the Minnesota Environmental Rights Act into law on June 7, 1971. According to the Minnesota Center for Environmental Advocacy, “MERA allows citizens to file lawsuits to protect Minnesota’s clean water, air, land, and other natural resources from pollution. It is an important and powerful law because it gives every person the right to protect the environment in court. In the 1970s, shortly after it was enacted, the Minnesota Supreme Court described MERA as giving Aldo Leopold’s “Land Ethic” the force of law.”
The Act includes three important rights:
•The right to civil action to protect natural resources (Minn. Stat. § 116B.03)
•The right to Intervention in administrative, licensing, or similar proceeding involving conduct likely to cause pollution, impairment, or destruction of a natural resource (Minn. Stat. § 116B.09)
•The right to challenge an “environmental quality” standard or decision that fails to protect natural resources. (Minn. Stat. § 116B.10)
This lawsuit uses MERA Section 10 alleging that the Minnesota Department of Agriculture’s Groundwater Protection Rules and Minnesota Pollution Control Agency’s Feedlot Rules are inadequate to protect our natural resources from nitrate pollution.

Minn. Stat. § 116B.01.
The legislature finds and declares that each person is entitled by right to the protection, preservation, and enhancement of air, water, land, and other natural resources located within the state and that each person has the responsibility to contribute to the protection, preservation, and enhancement thereof. The legislature further declares its policy to create and maintain within the state conditions under which human beings and nature can exist in productive harmony in order that present and future generations may enjoy clean air and water, productive land, and other natural resources with which this state has been endowed. Accordingly, it is in the public interest to provide an adequate civil remedy to protect air, water, land and other natural resources located within the state from pollution, impairment, or destruction.

You can read more about nitrates and coldwater fisheries here.

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