Iowa DNR 305(b) Water Quality Assessment Database

Iowa Fishkill Database Help

Data Disclaimer

Locational Data

Due to the changes in technology and the emphasis on data quality, the locational information for some of the older fishkills (pre-1995 or legacy data era) is an estimate only, and should not be accepted to be the precise location of the kill.

Modern data also has limitations on the accuracy of the fish kill locations, especially those where no formal investigations took place, such as natural kills on private farm ponds. The data point also represents the approximate location of the start of the kill, not the entire extent of the kill.

Numbers of Fish Killed

The numbers of fish killed should not be taken to be an exact count of fish. The number is always an estimate, since it is extremely difficult to count dead fish in flowing water conditions or when the kill is not reported immediately.

When possible, the number of fish killed in a kill event is derived from procedures outlined in the American Fisheries Society Special Publication 30 and in the Iowa Administrative Code Chapter 113. The enumeration of fish during a fish kill investigation provides a basis for determining the value of the fish killed when restitution from the responsible party is sought.

Less accurate counts occur in the following cases:

  • Fish kills that were reported several days after the event
  • Unfavorable conditions for counting fish such as high water levels or flows, ice, etc
  • Kills that are natural in origin

The reported number of fish killed in these cases is a rough estimate as determined by the field investigation staff, or by the account given by the person reporting the fish kill.

Records that do not have a number for fish killed, or display a zero, indicate that no official estimate was given at the time.

Legacy Data
Kill Cause Descriptions