The Integrated Report, which combines federal requirements for state Section 305(b) water quality assessments and Section 303(d) impaired waters listings, required the Iowa Department of Natural Resources Watershed Monitoring and Assessment Section to begin tracking fish kills. A fish kill can affect the 305(b) water quality assessment of the waterbody and can potentially result in the addition of the water body to the 303(d) list of impaired waters.
If you believe a fish kill has occurred, immediately contact the nearest Iowa DNR Field Office or Fisheries Office.
You should have available the name of the stream, the location of the kill, and any other conditions or observations that may aid in the investigation of the cause and source of the kill.
Do not touch the water or remove any dead fish.
515-725-8694
24-hour Environmental Reporting Hotline
Fish Kills and Water Quality Assessments
As described in Iowa DNR's current methodology for water quality assessments, occurrence of a single pollutant-caused fish kill, or a fish kill of unknown origin, on a waterbody or portion of a waterbody during the most recent three-year period indicates an impairment of the aquatic life uses.
Each report of a fish kill will be reviewed to determine whether development of a TMDL is appropriate. In the absence of an ongoing source of a pollutant, TMDLs will not be developed for kills caused by a one-time illegal or unauthorized release of manure or other toxic substance. Impacts from this type of fish kill are addressed through IDNR's enforcement procedures. Fish kills attributed to authorized discharges (i.e., a discharge meeting permit limits) are considered for Section 303(d) listing as the existing, required pollution control measures are not adequate to address this impairment.