West Branch Floyd River IA 06-FLO-1558

Assessment Comments

Assessment is based on occurrence of a fish kill in July 1998.

Basis for Assessment

SUMMARY:  The Class B(LR) aquatic life uses were assessed as "partially supported."  EXPLANATION:  The assessment of support of the Class B(LR) uses developed for the previous (1998) report ("fully supported / threatened"; see above) was based primarily on results from a DNR stream use assessment conducted in 1990.   The results from this assessment are now considered too old (greater than five years) to be useful for developing water quality assessments of current conditions.   A fish kill occurred in the general use reach of the West Branch Floyd River on July 8, 1998.   The kill occurred three miles east and 1 mile north of Hull in Sioux County.   The kill proceeded downstream for approximately five miles into the upper reaches of the Class B(LR) portion of this stream.   The kill was attributed to agricultural runoff from animal waste from a hog confinement operation; an estimated 7,900 fish were killed.   According to DNR's assessment methodology for Section 305(b) reporting, occurrence of a single pollution-caused fish kill within the most recent three-year period (1997-1999) indicates that the aquatic life uses of a waterbody are only "partially supported."  Thus, the assessment of support of the Class B(LR) aquatic life uses was assessed as "partially supported" due to this July 1998 fish kill.