Iowa’s 2024 list of impaired waters was only partially approved by the EPA, which said the state must add seven additional water segments to the list. (Photo by Cami Koons/Iowa Capital Dispatch)
The U.S. Environmental Protection Agency, after rejecting part of Iowa’s 2024 list of damaged water segments, is now asking for public comment on the decision to add seven water segments to the list.
Under the Clean Water Act, states are required to assess surface water quality and submit a report to the EPA every two years with a list of affected water bodies.
The Iowa Department of Natural Resources submitted the report Water quality assessment 2024 to the EPA in the spring and classified more than 700 water segments as impaired.
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EPA said in its recent letter to the declaration that the list only “partially complies” with the requirements under section 303(d) of the Clean Water Actwhich authorizes the EPA to assist states in identifying and developing water improvement plans for impaired waters.
Bad waters have an identified pollutant that exceeds water quality standards and require a water improvement plan, known as a Total Maximum Daily Load or TMDL.
The TMDL is established by the state and approved by the EPA for each affected water segment, after which all contributing polluters are allocated a portion of the allowable load. This determines the reduction in pollutants required to meet water quality standards.
The EPA has determined that one segment on the Cedar River, two segments on the Des Moines River, two segments on the Iowa River, one segment on the Raccoon River and one segment on the South Skunk River exceed water quality standards for nitrate and nitrate plus nitrite . related to drinking water use.
The EPA’s letter states that these segments should be on the Impaired Waters list due to their water levels nitrate and nitrite, which have “known toxicity.”
The EPA said it had asked Iowa in an earlier public comment to “revise” its assessment of nitrogen, nitrate, nitrite and nitrate plus nitrite, but the comments were “not adequately addressed by the state.”
“Iowa DNR has not revised its assessment of these parameters to adequately address them as pollutants with toxic effects, nor to reasonably consider the endpoints and adverse effects under consideration,” the letter said.
The DNR responded to the May 2024 public comment, saying it would not change its methodology because “the EPA has provided no new scientific evidence nor any new federal regulations in support of such a significant policy change.”
An Iowa DNR spokesperson said the department is reviewing the latest information in the EPA announcement and provided no further comment.
With the EPA’s additions, the 2024 list includes 712 affected water segments.
Iowa also delisted 84 damaged water segments that now meet water quality standards or have an EPA-approved TMDL. The EPA approved these 84 deletions and justifications.
The EPA has opened a public comment window for written comments on the seven proposed water segments from November 13 through December 13. Information about submitting comments can be found on the website agency website.
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