South Fork Iowa River IA 02-IOW-749

Assessment Comments

Assessment is based on occurrence of fish kills. See attached document for details.

Basis for Assessment

Continue to use the assessment of support of the aquatic life use developed for the 1994 report (=PS).   In addition, fish kills in July 1995 and August 1997, both due to illegal discharge of hog manure, suggest an impairment to the aquatic life uses in the upper reaches of the stream.   A review of the field sheets from the DNR stream use assessment in May and June, 1992, shows (1) fish communities with relatively poor diversity (7 species from 1 family) to moderate diversity (13 species from 4 families) for streams in the Des Moines Lobe subecoregion, (2) presence of a majority of the expected fish taxa (7 of 11) at only one of two assessment sites, and (3) indications of impacts to the physical characteristics of this stream from extensive channelization.   Follow-up monitoring is needed to better define the status of the aquatic communities in the stream reach and to detrmine the degree to which the Class B(LR) uses may be impaired, especially by residual effects of illegal/accidental discharges of animal waste.