Assessment Comments
Assessment remains based on results of IDNR/UHL monthly ambient monitoring near Turin in 1999 and 2000. (Note: the monitoring station near Turn (STORET station 10670001) was removed from the IDNR/UHL ambient network in September 2000.)
Basis for Assessment
SUMMARY: The Class B(WW) aquatic life uses are assessed (monitored) as "fully supported" based on result of chemcial/physical water quality monitoring in 1999 and 2000. Due only to a change in IDNR's assessment/listing methodology, the 2004 assessment of the Class B(LW) aquatic life uses ["fully supporting / threatened" (minor impacts)] is changed to "fully supporting". Other than this change in methodology, this new (2006) assessment is the same as that developed for the previous (2004) assessment/listing cycle (not impaired) and does not reflect any known change in water quality. Fish consumption uses remain "not assessed" due to the lack of fish contaminant monitoring in this river segment. This assessment is based on results of IDNR/UHL monthly ambient monitoring conducted during the 2000-2001 biennial period south of Turin in Monona Co. (STORET station 10670001 (formerly station 911090)). This is the same assessment as that developed for the 2002 and 2004 assessment cycles. Note: The IDNR/UHL ambient monitoring station south of Turin was dropped from the IDNR monitoring network after September 2000.
EXPLANATION: Monitoring at the IDNR station near Turin showed no violations of Class B(WW) water quality criteria in the 12 samples collected during the 2000-2001 biennial period for dissolved oxygen (minimum value = 7.3 mg/l), pH (range = 8.1 to 8.4 units), or ammonia-nitrogen (maximum value = 0.20). Levels of toxic metals in the four samples analyzed, and levels of pesticides in the two samples analyzed, were all below the analytical level of detection. Although these results suggest "full support" of the Class B(WW) aquatic life uses, the extensive habitat alterations in this stream system suggest at least a threat to full support of the aquatic life uses. Thus, these uses were assessed as "fully supported / threatened" (minor impacts) for the 2004 assessment/listing cycle. At the recommendation of U.S. EPA Region 7, however, IDNR's 2006 assessment/listing methodology was changed to eliminate use of the "fully supported/threatened" (minor impacts) category. Thus, previous assessments identified as "fully supported/threatened" (minor impacts) were changed to "fully supported" for the 2006 assessment/listing cycle. This change does not alter the 2004 assessment: this waterbody remains in IR Category 2a.
Fish consumption uses remain "not assessed" due to the lack of recent fish contaminant monitoring in this river segment.
