Major Rivers Put on Impaired Waters List

The federal Environmental Protection Agency (EPA) notified the Iowa Department of Natural Resources (DNR) that several Iowa rivers which are used for drinking water need to be put on the impaired waters list (the list is also called the 303(d) list) because they are polluted with nitrate and nitrite.  Nitrate and nitrite are toxic to humans.  The rivers are the Cedar River, Des Moines River, Iowa River, Raccoon River, and South Skunk River.

EPA is seeking comments about adding the Cedar River, Des Moines River, Iowa River, Raccoon River, and South Skunk River to Iowa’s 2024 303(d) list.  Send an e-mail by December 13, 2024, to R7-WaterDivision@epa.gov saying that you support adding the Cedar River, Des Moines River, Iowa River, Raccoon River, and South Skunk River to Iowa’s 2024 303(d) list.

Because 95% of Iowa’s land is farmed, the largest contributor to the nitrate and nitrite problem is manure and commercial fertilizer that runs off farm fields.  The cycle begins when plants do not absorb all of the fertilizer and manure that was applied to the fields.  Rain and snow melt transport the excess nitrate and nitrite off the fields and into rivers, streams, and lakes.

The impaired waters list, which is created by the DNR every two years, identifies the rivers, streams, lakes, and wetlands that are polluted.  The EPA is responsible for approving the impaired waters list that is created by the DNR.

EPA told DNR that they were using the wrong method to determine if a water body exceeds the water quality standard for nitrate and nitrate in surface waters used for drinking water.  The correct method is to use each test to determine if the nitrate, nitrate, or nitrate plus nitrite was higher than the water quality standard. 

The DNR was using a statistical method to determine the amount of nitrate and nitrite in those rivers used for drinking water.  That method allowed the DNR to avoid listing the waters on the impaired waters list.

Even worse, EPA told DNR about the problem during the open comment period on the draft list.  DNR ignored EPA’s comments and submitted the 2024 impaired waters list without listing the Cedar River, Des Moines River, Iowa River, Raccoon River, and South Skunk River on the impaired waters list.  

Source:

United States Environmental Protection Agency Region 7, 2024 Decision Document, Iowa's Clean Water Act Section 303(d) List of Water Quality Limited Segments Still Requiring TMDLs, November 12, 2024