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Assessment Comments

Assessment is based on IDNR/UHL water quality monitoring conducted as part of TMDL development from March through September 2005 at station 11300011.

Basis for Assessment

[Note:  Prior to the current (2008) Section 305(b) cycle, this stream segment was classified only for general uses.   Due to changes in Iowa’s surface water classification that were approved by U.S.  EPA in February 2008 (see http://www.iowadnr.com/water/standards/files/06mar_swc.pdf), this segment is now presumptively designated for Class A1 (primary contact recreation) uses and for Class B(WW1) aquatic life uses.   According to the Iowa Water Quality Standards, all perennial rivers and streams and all intermittent streams with perennial pools that are not specifically listed in the Iowa surface water classification are designated as Class A1 and Class B(WW1) waters.   Thus, for the current (2008) assessment, the available water quality monitoring data will be compared to the applicable Class A1 and Class B(WW1) water quality criteria.   This waterbody has not been assessed for Section 305(b)/303(d) purposes prior to the current (2008) assessment/listing cycle.]

SUMMARY:  The Class A1 primary contact recreation uses are not assessed due to the lack of information upon which to base an assessment.   The Class B(WW1) aquatic life uses are assessed (monitored) as “fully supported” based on results of chemical/physical water quality monitoring during 2005.   The source of data for this assessment is the results of IDNR/UHL water quality monitoring conducted as part of TMDL development from March through September 2005 at station 11300011.  

EXPLANATION:  The Class A1 (primary contact recreation) uses are not assessed due to the lack of data for indicator bacteria (E.  coli) upon which to base an assessment.   The TMDL monitoring conducted at this station in 2005 did not include monitoring for indicator bacteria.  

The Class B(WW2) aquatic life uses are assessed (monitored) as “fully supported” based on results of IDNR/UHL TMDL-related water quality monitoring conducted in 2005 at station 11300011.   Results of this monitoring show no violations of Class B(WW2) water quality criteria for pH or ammonia in the 11 samples collected or for dissolved oxygen in the 10 samples collected from March-September 2005.   According to U.S.  EPA guidelines for Section 305(b) water quality assessments (U.S.  EPA 1997b, page 3-17), these results suggest “full support” of the Class B(WW2) uses in this river segment.