Iowa DNR

Water Quality Assessments

Impaired Waters List

ADBNet Documentation


Iowa’s List of Waters in Need of Further Investigation

The list of waters in need of further investigation (WINOFI), as required by Iowa’s Credible Data Law, is comprised of those waterbodies assessed as “potentially impaired” and placed in Integrated Report Category 3b. As stated in the rationales for subcategory 3b, the assessment of any impairment in these waterbodies was based on less than complete information that suggests only a potential impairment. Thus, the assessments are of relatively low confidence and are not appropriate for addition to Iowa’s impaired waters list. When reporting these waterbodies to the US EPA, these waters are considered "Not Assessed".

In recent years, the Iowa Department of Natural Resources has begun several efforts to reduce the number of waters on the WINOFI list and investigate these waters so that they may be fully assessed.

In 2011, the DNR developed the Fish Kill Follow-up program to conduct biological sampling on segments where fish kills had occurred. The results of these surveys provide data on the recovery of fish communities after a fish kill.

Beginning in 2021, additional stream monitoring is conducted to provide both biological and water monitoring data to further assist the assessment process. Due to the timing of the Integrated Report assessment cycle, these data will not be available until the 2024 cycle.

Starting in 2018, additional lake sampling has been conducted, providing a large amount of water monitoring data for lakes, reservoirs, shallow lakes, and wetlands. These data will be used for assessments starting in the 2022 cycle.

This page was created 4/17/2017 2:04:55 PM and was last updated 11/5/2021 2:32:34 PM