May 13, 2025
DES MOINES – Alliant Energy’s Iowa affiliate, Interstate Power and Light (IPL), has agreed to stop discharges of polluted groundwater under an Ottumwa coal ash landfill. The move followed a 60-day notice of intent to sue under the Clean Water Act for unauthorized discharges issued by the Iowa Environmental Council (IEC), Sierra Club, and Environmental Law & Policy Center (ELPC). The coal ash at the landfill comes from the Ottumwa Generating Station co-owned by IPL and MidAmerican Energy.
“Coal plants create toxic pollutants that have long lasting health and environmental impacts. IPL’s unpermitted discharge of pollutants upstream of the City of Ottumwa’s drinking water source is one more example of why we need to shut down coal plants,” said Josh Mandelbaum, Senior Attorney with ELPC. “The best way to ensure toxic pollutants stay out of our drinking water is to stop the underlying polluting activity.”
“No one is allowed to have uncontrolled discharges of pollution into Iowa’s waters, and Alliant Energy is no exception,” said Michael Schmidt, General Counsel for IEC. “The Clean Water Act specifically restricts this type of pollution to protect our waters from dangerous chemicals.”
The notice of intent to sue alleged that Alliant’s Iowa affiliate discharged polluted groundwater from the site for decades. Iowa Department of Natural Resources informed IPL in 2023 that the discharge did not qualify under the company’s stormwater permit.
The utility’s own monitoring shows the water contains arsenic, cobalt, manganese, molybdenum at levels above groundwater or drinking water standards, as well as other heavy metals. The polluted groundwater was being discharged to a wetland that flows to a creek, then into the Des Moines River. Alliant proposed last year to discharge the water directly to the Des Moines River upstream of the City of Ottumwa drinking water intake, which led to environmental objections. Sierra Club and IEC highlighted the risks from coal ash waste in Iowa, including Ottumwa, earlier this year.
“The people in Ottumwa and the people downstream of the coal plant on the Des Moines River deserve to know that the water they drink, fish, and enjoy all summer is safe,” said Pamela Mackey Taylor, Sierra Club Iowa Chapter Director. “Toxic wastewater pollution from coal ash can cause cancer, damage the kidneys and liver, and is linked to reproductive harm and fetal developmental issues, not to mention impacts to fish and wildlife. The only real solution is to shut down the plant and transition fully to solar and wind power paired with battery storage.”
Alliant informed the environmental groups that it would temporarily truck polluted water to the City of Ottumwa Water Pollution Control Facility or for evaporation at the coal plant. Trucking polluted water to the city facility is both expensive and ineffective.
City water treatment plants are not equipped to properly handle coal ash. The treatment technology (biological or chemical settling) is ineffective at removing certain toxics and heavy metals, such as mercury, from wastewater.
IEC, Sierra Club, and ELPC believe that IPL should implement a permanent solution that treats the pollution from the coal ash landfill and stops harming public health and the environment. Further, IPL and MidAmerican customers should not have to pay for IPL’s failure to properly manage the pollution from its coal ash landfill.
The change in disposal practices by IPL occurred days before expiration of the 60-day period in the notice of intent to sue from the environmental groups.