Assessment Comments

Assessment is based on results of IDNR ambient monthly monitoring in 2000 & 2001 and (2) IDNR/UHL biocriteria sampling in 1998 (Fish IBI= 30(fair), BM-IBI= 59(fair)).

Basis for Assessment

SUMMARY:  The Class B(WW) aquatic life uses remain assessed as "fully supported / threatened."  Fish consumption uses remain assessed "not assessed."  This assessment is based on (1) results of IDNR monthly ambient monitoring conducted during the 2000-2001 biennial period at the State Highway 2 bridge 2 miles east of Clarinda (station 10730002 (formerly station 780809)) and (2) results of IDNR/UHL biocriteria monitoring in 1998.   EXPLANATION:  Monitoring at the IDNR station east of Clarinda showed no violations of Class B(WW) water quality criteria during the 2000-2001 biennial period for dissolved oxygen (minimum value = 7.7 mg/l), pH (range = 7.4 to 8.5 units), or ammonia-nitrogen (maximum value = 0.90) in the 24 samples analyzed during the 2000-2001 period.   In addition, levels of toxic metals in the four samples analyzed, and levels of pesticides in the six samples analyzed, were all below the analytical level of detection.   These results suggest "full support" of the Class B(WW) aquatic life uses.   Results of the IDNR biocriteria monitoring in 1998, however, suggest that the Class B(WW) uses are "fully supported / threatened" (see assessment for the 2000 report above).   Fish consumption uses remain "not assessed" due to the lack of recent fish tissue monitoring in this river reach.