Little Sioux River IA 06-LSR-1570

Assessment Comments

Assessment is based on results of IDNR monthly ambient monitoring near Larrabee in 1993-1995 and IDNR fisheries surveys conducted in Cherokee and O'Brien counties in 1989; sampling by J. Olson and D. Howell.

Basis for Assessment

Based assessment primarily on results of WQ monitoring at the DNR monitoring station approx 4 mi E of Larabee; this station was monitored from October 1993 through September 1995.   Monitoring results show no violations of Class B(WW) WQ criteria for either conventional or toxic contaminants in the 8 samples collected over the October 93 to September 1995 period (=FS).   One of the three non flow-affected samples contained levels of fecal coliform bacteria that exceeded the Class A primary contact water quality criterion (=200 organisms/100 ml).   Due to less than 10 data points for the two year period, evaluate support of the Class A uses as FST.   Results of the 1989 DNR fisheries surveys are probably still valid but are too old (i.e., > 5 years) to be used for making "monitored" Section 305(b) assessments.