Shell Rock River IA 02-SHL-783

Assessment Comments

Assessment is based on results of IDNR/UHL ambient monthly monitoring at Shell Rock, Butler Co., from 2002-04.

Basis for Assessment

SUMMARY:  The Class B(WW) aquatic life uses were assessed (monitored) as "fully supported" based on results of IDNR/UHL ambient water quality monitoring conducted during the 2002-2004 assessment period.   [This river segment was not designated for Class A (primary contact recreation) uses during this assessment period.]  Fish consumption uses remain “not assessed” due to the lack of fish contaminant monitoring in this river segment.   The source of data for this assessment is the results of monthly (plus) ambient water quality monitoring from January 2002 through December 2004 at the IDNR/UHL ambient station located at the County Road C45 bridge at Shell Rock, Butler Co.  (STORET station 10120001).  

EXPLANATION:  Monitoring at this station from 2002 through 2004 showed no violations of Class B(WW) water quality criteria for the following parameters:  dissolved oxygen or pH in the 53 samples analyzed; pesticides in the nine samples analyzed; and toxic metals in the 10 samples analyzed during this assessment period.   These results suggest that the Class B(WW) aquatic life uses should be assessed as “fully supported”.   This assessment is consistent with the assessment for the previous (2004) Section 305(b) reporting cycle.  

Fish consumption uses remain “not assessed” due to lack of recent fish tissue monitoring in this river segment.