Tipton Creek IA 02-IOW-755

Assessment Comments

Assessment based on extensive fish kills in 1996 and 1998.

Basis for Assessment

The Class B(LR) aquatic life uses remained assessed as "partially supported."  EXPLANATION:  Continue to use the previous assessment of support of the Class B(LR) uses developed for the 1998 report.   This assessment was based primarily on the occurrence of extensive fish kills near Williams, IA, in August 1996 and July 1998.   The 1998 assessment was also based, in part, on the results of a DNR stream use assessment in May 1992.   The results of this stream assessment, however, are greater than five years old and are thus considered too old to be useful for assessing current water quality conditions.   The most recent fish kill occurred near Williams, IA, on July 20, 1998 (see above).   This kill began approximately 2 miles upstream from the Hamilton / Hardin county line; approximately 11 miles of stream were affected.   According to DNR's assessment methodology for Section 305(b) reporting, occurrence of a single pollution-caused fish kill within the most recent three-year period (1997-1999) indicates that the aquatic life uses of a waterbody are only "partially supported."   The occurrence of the extensive fish kill in July 1998, and the potential for additional kills in this fishkill-plagued watershed, suggest a continuing impairment to the Class B(LR) aquatic life uses.