Iowa DNR

Water Quality Assessments

Impaired Waters List

ADBNet Documentation

Integrated Report Categories

As specified in U.S. EPA’s guidelines, the integrated report consists of five categories:

  • Category 1: All designated uses are met.
  • Category 2. Some of the designated uses are met, but there are insufficient data to determine if the remaining designated uses are met.
  • Category 3: Insufficient data to determine whether any designated uses are met.
  • Category 4: Waterbody is impaired or threatened but a TMDL is not needed.
  • Category 5: Waterbody is impaired or threatened and a TMDL is needed.

In their guidance to states, U.S. EPA has added the following Integrated Report subcategories:

  • Category 4a: All TMDLs need to result in attainment of all applicable water quality standards have been approved or established by EPA.
  • Category 4b. Other required control measures are expected to result in the attainment of water quality standards in a reasonable period of time.
  • Category 4c: The impairment or threat is not caused by a pollutant.

The U.S. EPA guidelines allow states to create additional subcategories in order to refine the reporting process. In order to better track the attainment status of Iowa waterbodies, the following subcategories have been created by the Iowa DNR:

  • Category 3b: Insufficient data to determine whether any designated uses are met but at least one use is potentially impaired.
  • Category 4d: Waterbody assessed as “impaired” due to a fish kill where enforcement action was taken to address the source of the kill: no TMDL required.
  • Category 5b: Impairment is based on results of a fish kill investigation or biological monitoring where specific causes and/or sources of the impairment have not yet been identified.
  • Category 5p: A presumptively-applied use is impaired (most often applied to bacterial impairments of the presumptively applied Class A1 (primary contact recreation) use).

This page was created 4/17/2017 1:58:28 PM and was last updated 11/5/2021 1:00:03 PM