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DNR releases latest draft of 303d impaired waters list

  • 2/21/2022 4:11:00 PM
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DES MOINES -- The Iowa Department of Natural Resources is seeking public comment on the newly released draft impaired waters list. Data released by the Iowa DNR today shows 48 impairments are recommended to be removed from the 2020 303d impairment list, once the removals are approved by the EPA.

This report identifies surface waters that do not fully meet all applicable state water quality standards for their intended use and that need a water quality improvement plan. Of the 1,382 water segments studied, which include portions of rivers, streams, lakes, reservoirs, and wetlands, 15 segments fully met the Iowa water quality standards for their intended use, 321 segments did not have an impairment; while 295 segments were identified as needing further investigation, and 594 segments did not fully meet one or more of the standards needed for all their intended uses and were impaired.

“An increase or decrease in impaired waters does not necessarily mean that the water quality in the state is worsening or improving. It could be a reflection of the additional monitoring we are conducting, changes in water quality standards, and changes in assessment methodologies,” said Roger Bruner, supervisor of the DNR’s Water Quality Monitoring and Assessment section. “Impaired segments are often used for recreation and fishing, among other uses, so impairment doesn’t mean that the segments are unusable.”

3-Step Process for Impaired Waters Study

The DNR uses fixed station river monitoring, lake monitoring and beach monitoring, wadeable stream biological monitoring, fish tissue monitoring and wetland/shallow lakes monitoring. Several other data are also analyzed before determining whether a water segment does or does not meet the requirements like the Iowa DNR’s Fish Kill Database, along with federal (Army Corps of Engineers and US Geological Survey) and municipal (drinking water supplies) data and surrounding states’ data.

DNR’s process is to compile all available credible data in the correct time frame. The data from many different sources are reviewed and assembled into a standard format. Then, these results are compared to appropriate criteria for each designated use. The final assessment for each segment is a compilation of all these results (2,399 use assessments in this report).

Most Iowa waters are designated for both aquatic life protection and water contact recreation. Others also may include one or both designations for drinking water or human health protection.

“The DNR has a long history of working with Iowans across the state to help address our water quality challenges,” said Lori McDaniel, DNR Water Quality Bureau Chief. “The importance of this collective, persistent work is clear and will continue to be a priority for the DNR.”

Success stories: Get involved!

To keep the positive momentum moving forward to improve water quality in Iowa, the DNR is encouraging citizens to get involved. The DNR Watershed Improvement program provides assistance on how to start a water quality effort and seek grant opportunities.

Iowa has several water quality success stories including watershed improvements. To qualify as a success, there must be evidence of water quality improvement that led to an impairment delisting.

Public comment is welcomed now through March 19, 2022, and should be sent to:



Postal mail: Iowa Department of Natural Resources Attn: Impaired Waters/Segment List Water Quality Monitoring & Assessment Section Wallace State Office Building 502 E. Ninth St. Des Moines, IA 50319

recording of DNR staff discussing how to read and interpret the 2022 impaired water list is available.