Impaired waters report by Iowa DNR identifies potential trouble spots to fix

(The Center Square) – Some water segments in Iowa’s rivers and lakes tested as impaired but that doesn’t mean they are grossly polluted, a state Department of Natural Resources (DNR) expert said.

A draft report of impaired waters has been prepared by the Iowa DNR as required by the federal Clean Water Act, said Roger Bruner, who supervises a section in the water quality bureau at the Iowa DNR.

This initial testing identifies segments of rivers, lakes and wetlands that may need additional testing to create a watershed improvement plan, Bruner said.

Once a segment gets on the impaired waters list, another group within the DNR does more intensive testing to determine the sources of the impairment. Computer modeling helps develop practices to bring the water body back into meeting water quality.

“It has in the past been suggested by some groups, that it’s impaired, it’s grossly polluted, or it’s unhealthy to be in the water or something along that line, and that’s just patently not true. Especially here in Iowa,” Bruner said.

In the upper Iowa River and Lake Okoboji, some of most used recreation waters in the state are impaired for indicator bacteria, Bruner said. That does not prevent their use. Bruner said it gives a heads up that those waters aren’t meeting expectations, and something needs to be done.

In the past, meatpacking plants weren’t required to do anything to protect waterways.

“But everyone has dumped their waste into the river because it was convenient, and it got it out of your area right away,” Bruner said. “The rivers in Iowa, prior to the Clean Water Act, had some fairly significant impacts like that. Now the impairments we see are generally very minor.”

Every water segment has up to four designated uses, including recreation, aquatic life, public water source and human health, he said. Recreation includes swimming. In bodies of water deep enough for swimming indicator bacteria needs to be lower in case a person accidentally ingests water.

Aquatic life includes supporting game fish, but headwaters of streams are too shallow and won’t be fishable.

“Some small minnows might be able to survive and or some other types of aquatic insects, for example,” Bruner said.

Raw water gets tested where it’s pulled from a stream or lake.

“That raw water is compared to drinking water standards. That’s very conservative, because we wouldn’t expect anyone to drink raw water, that’s just not a recommendation anyone would make anywhere in the world,” Bruner said.

Human health becomes an important factor in testing favorite fishing spots. Protections are devised when needed so fish don’t build up a toxic amount of chemicals. Fish tissue monitoring is a big part of the determination as mercury is a worldwide problem.

Burning coal releases mercury into the atmosphere and rain brings it back down to the ground, making its way into the food chain and into fish, Bruner said. Iowa has a few spots for which the DNR advises anglers to restrict meals from fish caught there to once a week, but it does not have any segments completely restricted for eating.

The DNR is inviting comments on the specifics of the draft impairment list through Jan. 1, which can be submitted by email to [email protected].