Experts warn of sewage, E. coli in Missouri River: Flooding could make quality worse

The Kansas Department of Health and Environment advised residents last week to stay out of the Missouri River due to contamination from raw sewage and E. coli bacteria. Five days later, the river is still dangerous to enter—both due to high water levels and contaminants from upstream.

"KDHE advises residents to stay away from the river at this time. While the high flow conditions continue, do not enter the river," the department wrote in a news release June 27.

According to the department, severe flooding in Iowa and Nebraska caused untreated wastewater to be discharged into the river, raising levels of E. coli bacteria and other contaminants.

"Any time we have wet weather, we expect water quality to be degraded," said Tom Stiles, the KDHE's water bureau director. "It's unusual just to have this much rain come down, and that has overwhelmed some of the systems."

Here's what we know about contamination in the Missouri River, and how to stay safe until it subsides.

What's causing the sewage and bacteria in the Missouri River?

Extreme weather in Nebraska and Iowa has overwhelmed these states' local water treatment systems in the past week. These severe flood conditions have caused what experts call bypasses in wastewater plants and caused untreated sewage to enter the Missouri River.

"Sometimes there's too much water passing through a treatment plant to be able to be adequately disinfected, and that creates the bypass situation," Stiles told The Kansas City Star. Agricultural runoff and other contaminants from the land also get washed into the river after heavy rainfall.

Mike Kruse, the water protection program manager at the Missouri Department of Natural Resources, added that the contaminants have likely been diluted to less hazardous levels by the time they reach Kansas City.

"In most cases the sheer volume of water in the Missouri River, especially by the time it reaches Missouri, is so great that sufficient dilution has occurred," he said.

However, his department still advises the public against entering the water recreationally until flood conditions have subsided.

How can I stay safe from Missouri River contamination?

For now, experts advise that residents not enter the Missouri River until the contamination has been cleared out.

Stiles noted that he doesn't expect many boaters or anglers out on the Missouri this week anyway, due to the high water levels and rapid flow rate caused by upstream flooding. But if you do enter the water, a small splash on your skin likely won't have a negative effect. The risk of illness increases when you ingest or submerge yourself in the water.

"It's just common sense—you're in the open environment, afterwards you practice good hygiene, you shower, you basically just clean yourself up, and (there's) no risk to yourself," he said.

He also advised residents not to let their pets wade in the river—even if they don't drink any of the water, they could still consume the bacteria when cleaning themselves later.

Stiles also noted that residents shouldn't be worried about the quality of local drinking water. E. coli is easily treated with disinfectants, and water treatment facilities on both sides of the state line are well-equipped to handle this type of contamination, he said.

When will the Missouri River's water quality improve?

We don't know yet exactly when the advisories will be lifted—it all depends on when water treatment systems upstream are restored.

Stiles said that plants in Iowa are still experiencing bypasses as of July 2. And while wastewater treatment in Omaha is mostly restored, some smaller local water systems in Nebraska are still experiencing the impacts of last week's flooding as well.

Flood conditions are also expected in the metro area in the coming days. On the afternoon of July 2, the National Weather Service issued flood warnings in areas along the banks of the Missouri River.

Incoming rain will likely wash more contaminants into the river, potentially causing poor water quality to continue even after plants in Nebraska and Iowa are restored. The KDHE will announce when its advisory for the river officially lifts.

2024 The Kansas City Star. Distributed by Tribune Content Agency, LLC.