French Creek IA 01-UIA-248

Assessment Comments

Assessment is based on DNR biocriteria sampling and a DNR summary of trout reproduction.

Basis for Assessment

SUMMARY:  The Class B(CW) coldwater aquatic life uses remain assessed as "fully supported."  Fish consumption uses were assessed as "fully supported."  EXPLANATION:  Based on a summary of trout reproduction in Iowa streams prepared by the DNR Fisheries Bureau, the Class B(CW) uses were assessed as "fully supported."  According to Moeller (1999), French Creek is in the category of Iowa trout streams with long-term, consistent natural reproduction; these streams are capable of maintaining a viable population of trout without stocking.   A November 1999 report prepared by the Hawkeye Fly Fishing Association alleges that water quality in portions of French Creek has recently been adversely affected by siltation of coarse substrates and by organic enrichment as expressed through excessive growth of filamentous algae.   The source of these adverse impacts is believed to be farm fields used for land application of animal waste from a hog confinement facility.   Although a recent (1999) DNR biological assessment suggests excellent water quality in French Creek, the evidence presented in the HFFA report suggests a potential "threat" to the full support of aquatic life uses in this high quality coldwater stream.   See the following web site for more information on suspected water quality problems at French Creek:  http://www.commonlink.com/hffa/News_Flash/FC-Pollution-report.html.   Additional monitoring is needed to determine current water quality conditions in French Creek.   Thus, DNR, in cooperation with the University of Iowa Hygienic Laboratory, plans to conduct periodic follow-up monitoring of benthic macroinvertebrates at French Creek to document the status of water quality.   Fish consumption uses were assessed as "fully supported" based on results of EPA/DNR fish tissue (RAFT) monitoring in 1996 that showed very low levels of very few contaminants in the composite samples of fillets from white sucker and brown trout.   Levels of contaminants in both samples were far below ½ of the respective FDA action levels and DNR levels of concern.