Little Sioux River IA 06-LSR-1577

Assessment Comments

Assessment is based on results of IDNR/UHL ambient monthly city monitoring upstream of Spencer from 2000-02.

Basis for Assessment

[Note:  For the 2002 report, the previous waterbody segment for the Little Sioux River (IA 06-LSR-0040-1), which extended 44 miles from the confluence with the Ocheyedan River at Spencer (Clay Co.) to confluence with the West Fork Little Sioux River in Dickinson Co., was split into two subsegments:  (1) Ocheyedan River at Spencer to confluence with Milford Creek (Dickinson Co.) (IA 06-LSR-0040-1) and (2) Milford Creek to confluence with West Fork Little Sioux River (Dickinson Co.) (IA 06-LSR-0040-2).   See previous assessments from this subsegment for historic Section 305(b) assessments for the original 44-mile river reach.]

SUMMARY:  The Class B(WW) aquatic life uses remain assessed (monitored) as "fully supported" based on results of ambient chemical/physical water quality monitoring.   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 monitoring from May 2000 through December 2002 at the IDNR/UHL ambient city monitoring station located upstream from Spencer at the Highway 18 bridge northwest of Spencer (STORET station 10210002).  

EXPLANATION:  The Class B(WW) aquatic life uses are assessed as "fully supported" based on results of ambient water quality monitoring.   Monitoring at the IDNR/UHL city station showed no violations of Class B(WW) water quality criteria for dissolved oxygen, pH, or ammonia-nitrogen in the 28 samples collected, for toxic metals in the 28 samples analyzed, or for pesticides in the nine samples analyzed, during the 2000-2002 assessment period.   These results suggest full support of the Class B(WW) aquatic life uses.  

Fish consumption uses remain "not assessed" due to the lack of recent fish contaminant monitoring data for this river segment.