As central Iowa invests millions in water recreation, what does water quality report show?

Even as Central Iowa Water Works has lifted a lawn-watering ban prompted by elevated levels of nitrate pollution in the Des Moines and Raccoon rivers, high bacteria levels in the state’s waterways remain worrisome, according to a scientist involved in a recent study of Iowa’s water quality problems.

A recently released study for the Polk County government outlines the hazard as the region invests upward of $125 million in water recreation projects on central Iowa waterways. They include a downtown Des Moines whitewater course, wave generator and other amenities under construction on the Des Moines River and planned features for paddlers on the Raccoon River near Gray’s Lake Park.

The Central Iowa Source Water Resource Assessment involved 17 scientists who spent more than 4,000 hours analyzing the Des Moines and Raccoon river watersheds. The study’s release came amid a summer marked by Central Iowa Water Works’ unprecedented imposition of a mandatory lawn-watering ban affecting 600,000 customers.

CIWW said the ban that began June 12 and wasn’t fully lifted until Aug. 7 was necessary to ensure equipment for removing nitrate from source water drawn from the two rivers had sufficient capacity to meet essential water needs.

The U.S. Environmental Protection Agency limits nitrates in drinking water to 10 milligrams per liter, and concentrations in the rivers reached more than double that level as the summer began with heavy rainfall.

Consumption of water with high nitrate levels is linked to blood oxygen deficiencies in infants, and a growing body of evidence also ties the chemicals to cancer.

The conclusion of the study, which four of the scientists presented to a crowd of concerned residents at Drake University on Aug. 4, was clear: Agriculture is the primary driver of pollution in the river, particularly nitrates, which are a key component of fertilizers, and it poses ongoing risks to public health and economic well-being in Iowa.

But nitrates from agricultural runoff, which state leaders have steadfastly refused to regulate, aren’t the only hazard the report outlined in central Iowa’s waterways. Levels of E. coli, antibiotic-resistant bacteria and harmful toxins produced by algal blooms also are high enough to be significant concerns, the study said.

Claire Hruby, a professor of environmental science and sustainability at Drake University and one of the scientists behind the report, said during the Aug. 4 presentation that aquatic recreation in Iowa carries serious risks, not just from agricultural runoff but also from untreated human waste reaching waterways.

The Iowa Department of Natural Resources regularly tests water at beaches on public lakes in the state and provides warnings when bacteria reaches hazardous levels. Rivers and streams aren’t as closely monitored, but the report shows they often carry high bacteria levels.

Hruby said the risks related to water recreation not only affect public health, but also economic development.

“If we put a lot of time and money, taxpayer dollars into our waterways and recreation, we need to make sure that that water is safe, or else we’re perhaps wasting our money,” she said.

Kaitie Hartmann, spokesperson for Iowa Confluence Water Trails, the organization leading the water recreation plan. told the Des Moines Register in June that the report is on data that’s been readily available for years, and it doesn’t change ICON’s approach to its projects.

Here’s what to know about the report’s findings on water recreation in central Iowa.

Why are scientists worried about water recreation?

In addition to nitrates, microorganisms including viruses and bacteria have been found in central Iowa’s lakes and streams. Some can cause illness or even, in rare cases, death.

Long-term monitoring found that more than half of the field samples from the Raccoon River at Fleur Drive exceeded the EPA’s swimming advisory threshold for E. coli, the study found. About 15% of samples even surpass the higher thresholds recommended for less direct recreational uses such as boating or wading.

In addition to agricultural runoff from livestock operations and manure-fertilized farm fields, sources of E. coli at beaches can come from humans, including leaky diapers or wastewater, as well as waterfowl and other animals.

Scientists say with genetic testing of the water to help identify the fecal matter in it, they’re finding human waste, particularly in Polk County’s urban areas.

“In Polk County, we’re seeing significant amounts of human DNA in our waters — evidence we still have work to do on our human waste infrastructure,” Hruby said. “If you get an infection from recreational water that’s antibiotic-resistant, it can be much, much worse. We’re finding resistance genes for critical antibiotics — some from human wastewater, some from livestock.”

People who come in contact with the rivers and streams are at risk when they swallow water or get it in their eyes, nose, ears or open wounds. It can cause an upset stomach, diarrhea and skin infections.

The chance of getting sick — and how severe the illness is — could depend on the types of pollutants, how many are present in the water and how much water people ingest, the study said.

Many of central Iowa’s more serious waterborne diseases peak in the summer, which is likely tied to more recreation, the study showed. But the exact number of illnesses caused by water in Iowa is unknown because of delayed symptoms and lack of reporting.

The study noted that monitoring the water is important to understanding the risks that water-borne illnesses pose, as well as how to address cleanup efforts.

More: Polk County report: Majority of central Iowa water pollution tied to farming

How do scientists measure recreational risks?

Not all E. coli is bad, but monitoring the bacteria can alert people to the potentially harmful organisms that come from human and animal waste, according to the study

The U.S. Environmental Protection Agency sets standards for E. coli in water for recreation, measured based on the count of E. coli in 100 milliliters of water — or about half a cup — and the number of people who get sick after swimming.

The risk is dependent on the type of activity and the age of the person. For swimming or children playing, which can lead to a lot of water ingestion, the safety standards is 235 or fewer E. coli per 100 milliliters. For activities such as fishing and kayaking, which involve less exposure, the standard is 2,888 E. coli or fewer.

These standards apply from May 15 to Nov. 15, since E. coli levels are usually lower during winter and early spring, the report said.

Are there other ways to measure risks?

In addition to monitoring E. coli levels, the Iowa Department of Natural Resources also has started testing a small number of beaches for common disease-causing organisms using genetic analysis. Scientists estimated the risk of becoming ill from bad bacteria depending on the type of recreation.

The highest average risks for people in central Iowa were found in Beaver Creek, followed by Walnut Creek, the Racoon River, Fourmile Creek and the Des Moines River, a 2024 study found. It used microbial source tracking, a method that looks for DNA sequences that show the presence of fecal waste from humans, pigs, cows, birds and other sources.

More: 5 takeaways from Iowa water quality report that points to agriculture as nitrates source

What other concerns have come up?

Scientists are also concerned about Naegleria fowleri, commonly called a “brain-eating amoeba.” These microscopic, single-celled organisms are found in warm freshwater and can cause a rare, life-threatening infection if they enter the brain through the nose.

While no cases have been reported in central Iowa as of August 2024, a trend of rising temperatures could increase the risk, the report states.

In July 2022, a Missouri resident died after being infected by Naegleria fowleri while swimming in Lake of Three Fires State Park about 100 miles southwest of Des Moines. A month later, the U.S. Centers for Disease Control and Prevention confirmed a Nebraska child died of the infection after swimming in a river near Omaha.

A Missouri resident died Aug. 20 after contracting the amoeba from exposure to water in the Lake of the Ozarks, the state’s premier destination for boating, the St. Louis Post-Dispatch reported.

The Central Iowa Source Water Assessment also pointed to a rise in antibiotic-resistant bacteria, which is quickly becoming a health problem, according to the World Health Organization.

People and animals rely on antibiotics to stay healthy, and over time, all microorganisms develop a resistance, the study said. But scientists say due to the overuse and misuse of antibiotics, antibiotic-resistant bacteria and genes are becoming quickly widespread.

In addition, during her presentation Aug. 4, Hruby said harmful algal blooms can produce toxins that can pose serious risks for drinking water and recreation. From 2006 to 2013, the Iowa DNR found microcystins, toxins formed in blue-green algae, at least once in all 60 sites it checked, the report said. Of 6,752 samples taken, 107 exceeded the safe limit.

The algal blooms thrive in stagnant water, particularly during droughts. In 2020, microsystin levels in the Des Moines River became high that for a period, Central Iowa Water Works member Des Moines Water Works was unable to use the river as a drinking water source.

Exposure to the toxin can cause rashes and, in more severe cases, major organ failure, Hruby said.

More: Central Iowa Water Works drops request for 25% voluntary cut in lawn irrigation

Why do rivers typically have higher levels of E. coli than beaches, lakes?

The study also said the risk of exposure in streams and rivers is often higher than at beaches or lakes. The risk can change depending on the site and the month.

Rivers and streams are not monitored weekly like beaches and lakes, the study noted. Where rivers are monitored, data show E. coli levels that are regularly higher than the standards for safe recreation. That’s because moving water can pick up E. coli from the surrounding landscape and bottom sediments, the study said

The study showed an example from spring 2024, when the amount of E. coli in Polk County rivers and streams exceeded 10,000 per 100 milliliters of water, well above the recreational standards.

E. coli levels are usually highest when stream flows are high. But the study shows high E. coli also can proliferate during dry periods when waste from livestock lagoons, municipal wastewater plants and leaky sewers enter waterways undiluted.

What do ICON leaders say about the study?

ICON includes more than 50 proposed developments on 150 miles of waterways in central Iowa.

The Center Street site, where ICON plans to renovate the Center Street dam on the Des Moines River beneath downtown Des Moines’ Iowa Women of Achievement pedestrian bridge and add a whitewater course, would be one of the initiative’s gems,

Hartmann told the Register in June that ICON leaders agree the water quality is “not at a place where we want it to be,” but that change is going to require continued prioritization from both the public and private sectors.

She said while the levels of disease-causing microorganisms in the water are concerning, “the data in the report shows that most of the waterways that would be falling within the ICON network are below EPA standards for (limiting) recreation behavior.”

“We are absolutely concerned with what is in the water, and we want to make sure that recreators have access to the information that will help them make the most informed decision possible,” she said.

Hartmann said ICON will continue to advocate for federal safeguards and funding for waterways and adhere to recommendations by American Rivers, a clean water watchdog and advocacy group, for restoring waterways. Those measures include restoring damaged floodplains, mitigating low-head dams and providing educational opportunities and increased access to waterways.

“What we see our role in this initiative is to build a conservation ethic among Iowans by way of creating more opportunities to engage with our natural resources,” Hartmann said.

What about fishing?

Polk County is the most frequently fished county in the state. In 2019, Polk County residents bought more than 32,500 fishing licenses, the study noted.

According to the report, 47% of anglers at Scott Avenue and Center Street dams reported that fish were an important food source for their family.

Hruby said there isn’t enough data to show what’s in the fish, but that there needs to be additional testing.

“And we need to do a better job of regularly testing those fish because fish can bioaccumulate certain contaminants over time, especially the larger ones and the ones that feed off the bottom,” she said.

Virginia Barreda is the Des Moines city government and Polk County reporter for the Register. She can be reached at vbarreda@dmreg.com. Follow her on X at @vbarreda2.

Tips on swimming in central Iowa waterways

Hruby recommends that those engaging in aquatic recreations should:

• Wash hands with soap or use hand sanitizer

• Minimize the amount of water that enters the nose and mouth

• Stay out of the water if they have open wounds or lowered immunity

• Tell a doctor the time and place of exposure to water if they fall ill.

This article originally appeared on Des Moines Register: What does Iowa water quality report say about swimming, kayaking?