Elk Run IA 02-IOW-763

Assessment Comments

Stream use assessment in Hardin County.

Basis for Assessment

Used a review of the field sheet from the June 1992 DNR stream use assessment near Iowa Falls to downgrade the assessment of support of the Class B(LR) aquatic life uses from FST to PS due to (1) presence of less than a majority of the expected fish taxa (5 of 11) for streams in the Des Moines Lobe subecoregion (47b) (primarily due to absence of several cyprinid species) and (2) due to results of a 1985 DNR fish survey that suggested a recent fish kill.*  The relatively poor sample results from the June 1992 stream use assessment may have been due to the poor sampling conditions present (i.e., high, turbid water).   Follow-up monitoring is needed to better determine the status of the aquatic communities and to determine the degree to which the Class B(LR) uses may be impaired.   *The June 1985 survey produced only four fish (2 blacknose dace and 2 white suckers) in approximately 45 minutes of sampling with a backpack electrofisher.   The quality of the aquatic habitats was above average.   The water was extremely (i.e, unnaturally) clear, thus suggesting the absence of the expected aquatic life.