State's Triennial Review of Iowa's Water Quality Standards Fails to Address Nutrient Pollution

posted on Wednesday, January 8, 2020 in Water and Land News

State water quality standards still do not address public health threats

Des Moines, IOWA – The State of Iowa has once again chosen to ignore dangerous nutrient pollution in Iowa’s waters by refusing to adopt numeric nutrient criteria. This refusal comes as part of the Iowa Department of Natural Resources’ (DNR) Triennial Review work plan for 2018-2020 state water quality standards, released in late December 2019.

The Clean Water Act requires the Triennial Review to be completed every three years. The review identifies priorities and establishes a work plan to update the state’s water quality standards during a three year period. This work plan is significantly overdue, with two-thirds of the planned work schedule already passed.

“The state’s refusal to properly address nutrient pollution puts Iowans at risk,” says Ingrid Gronstal Anderson, Water Program Director with the Iowa Environmental Council (IEC). “Despite the clear environmental impacts, economic risks, and health concerns related to unchecked nutrient pollution, the DNR has proposed little change to any water quality standards to protect human health for the 2018-2020 work period.”

The DNR selected three priorities for the Department to focus on during the 2018-2020 period. The priorities include:

  • updating stream and lake Use Attainability Analyses (UAAs) that determine how Iowans use lakes, rivers, and streams (i.e. aquatic life uses, recreation and drinking water);
  • revising water quality standard values for metals to protect aquatic life; and
  • ending the rulemaking process for water quality certifications for United States Army Corps of Engineers regional and nationwide permits.

Despite the high number of public comments the DNR says it received in favor of adopting numeric nutrient criteria to address nutrient pollution (nitrogen and phosphorus), it is not listed among the agency’s priorities.

The current nutrient-related pollution standard used by the state is a narrative standard that says water shall be free from “aesthetically objectionable conditions” and “nuisance aquatic life.” However, the narrative standard does not include an objective way to determine whether conditions are, in fact, objectionable. Iowa is the only state in the Upper Mississippi River basin that has refused to adopt any numeric state water quality standards for nutrients.

Numeric criteria would define specific numbers that would limit nutrient pollution for the protection of public health, aquatic life, drinking water sources, and recreation opportunities. Nutrient pollution threatens human and animal health in numerous ways, including delivering high levels of nitrate in drinking water, which has been linked to increased risk of some types of cancer, or driving the growth of Harmful Algae Blooms (HABs) that can release dangerous toxins. In 2019, the DNR issued public beach advisories 21 times when high levels of toxins from algae exceeded the state’s advisory threshold for recreation.

In response to public comments requesting the adoption of numeric nutrient criteria, the DNR stated that Iowa’s Nutrient Reduction Strategy (NRS) addresses nutrient pollution issues. However, the NRS has no benchmarks or limits, and is not a substitute for water quality standards under the Clean Water Act.

Additionally, the DNR makes no mention of plans to establish or adopt numeric nutrient criteria in the future, despite continued statements that establishment of such criteria is a “long term goal.” Iowa’s 2006 nutrient criteria development plan stated that numeric criteria for lakes would be adopted in 2007; in 2008, a state science advisory panel developed criteria for recreational lakes that were formally recommended to DNR. In 2013 and 2019, the DNR’s Environmental Protection Committee denied IEC’s petitions requesting the state set such numeric standards.

“More than a decade later, the state has made zero progress on adopting numeric standards. By refusing to set numeric nutrient criteria, the state shows that the health of Iowans is a low priority,” said Gronstal Anderson. “We call on the DNR to reconsider its dereliction of duty and start the rulemaking process.”


  1. beach advisories
  2. clean water
  3. dnr
  4. harmful algal blooms
  5. microcystin
  6. nitrate pollution
  7. phosphorus pollution
  8. public beaches
  9. water quality