116 3rd St SE
Cedar Rapids, Iowa 52401
Iowa has 576 sections of impaired waterways
But Lake Macbride near Solon was removed from the 2024 list
Iowa has 576 water body segments on its 2024 draft list of impaired waters, a net reduction of 21 from the 2022 count.
Still, more than half of Iowa’s assessed streams and rivers had impairments and 63 percent of lake or reservoir segments were impaired in the new draft list released Thursday by the Iowa Department of Natural Resources.
High levels of bacteria were to blame for 44 percent of river and stream impairments and turbidity and algal growth were the largest causes of lake, reservoir and wetland impairments. Other causes were fish kills, fish consumption advisories and high acidity.
Here are some changes in 2024:
- Coralville Lake, which already was listed as impaired for bacteria and turbidity, now also is listed as impaired for algal growth caused by agricultural pollution, the Iowa DNR reported.
- Bloody Run, a popular trout stream in Northeast Iowa, also gained an impairment in 2024. The stream was listed as needing more investigation in 2022 after a fuel spill. The department now has added “low biotic index,” which reflects diminishing fish habitat.
- Lake Macbride, near Solon, was removed from the impaired water list. The lake was delisted because samples taken in 2020, 2021 and 2022 showed lower levels of E. coli and measurements for algal growth also improved between 2020 and 2022, the Iowa DNR reported.
Macbride’s delisting is somewhat surprising, given the beach there had seven weeks of swim advisories last summer for high levels of E. coli bacteria, which indicates feces in the water.
“The integrated report cycle is done in arrears. You look at data two years prior,” Noah Poppelreiter, supervisor of the Iowa DNR’s water monitoring staff, said about the list. “We’re always going to see some fluctuations up and down that may not be reflected in the integrated report.”
The department’s beach monitoring program, which takes weekly water samples throughout the summer, also is an important tool, he said. “It gives people a much more current data, as opposed to the two-year time lapse between the summer of 2022 and summer of 2024.”
The federal Clean Water Act requires states to list water body segments not meeting state water standards for their designated uses, such as drinking water, recreation or aquatic life. The Iowa DNR is charged with creating water quality improvement plans (called the Total Maximum Daily Load) for all the impaired, or Category 5, segments.
In 2006, the Iowa DNR crafted a TMDL for a portion of the Cedar River extending from Bear Creek in Palo to McLoud Run in Cedar Rapids. This section is where the city of Cedar Rapids gets its raw drinking water, through shallow wells beside the river. The goal was to reduce nitrate pollution.
The Iowa DNR said in 2022 it planned to withdraw the Cedar River TMDL because some criteria in the plan were too stringent. A former agency supervisor told The Gazette in 2022 he thought withdrawing the TMDL went against federal law.
“While I was working at DNR — when I was being coaxed, cajoled, pressured, any and all of the above to rewrite that TMDL — I kept pointing out, ‘Hey, there's nothing wrong with the TMDL,’” said Allen Bonini, the former watershed improvement section supervisor who retired in 2021. “There's nothing in the Clean Water Act, its enabling regulations or any of the case law that would suggest that we have any legal right to rewrite the TMDL.”
As of last August, the Iowa DNR still hadn’t made a decision about the plan, which still is listed among 128 TMDLs in Iowa.
The department is seeking public comment on the draft impaired water list through April 15 at IRcomment@dnr.iowa.gov.
Comments: (319) 339-3157; erin.jordan@thegazette.com
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