Trout Creek (aka Trout Run) IA 01-UIA-269

Assessment Comments

Assessment is based on results of fish / benthic macroinvertebrate monitoring in 1998 and 1999. See attached document for details.

Basis for Assessment

The Class B(CW) aquatic life uses were assessed as "fully supporting / threatened" (minor impacts).   Fish consumption uses remain "not assessed."  EXPLANATION:  The support of the Class B(CW) [coldwater] aquatic life uses was upgraded from "partially supported" to "fully supported / threatened" based on results of biological monitoring (fish and benthic macroinvertebrates) conducted from 1997 through 1998 by the University of Iowa Hygienic Laboratory (see UHL 1999).   These studies show that water quality in this stream reach (site TR1) was rated as "very good" in 1998 and 1999 based on the Hilsenhoff Biotic Index.   Although these studies have been conducted to document changes in water quality in response to improved watershed management practices, this connection has not been demonstrated in the project thus far, with annual changes in fish populations and benthic macroinvertebrate populations more likely a response to variations in precipitation, runoff, stream flow, temperature, and other climate-related factors (see UHL 1999).   Fish consumption uses remain "not assessed" due to the lack of fish contaminant monitoring in this stream reach."