North Fork Maquoketa River IA 01-NMQ-91

Assessment Comments

Assessment based on reports of fish kills.

Basis for Assessment

SUMMARY:  The Class B(LR) aquatic life uses remain assessed as "partially supported."  EXPLANATION:  The previous assessment of the Class B(LR) uses was based on DNR stream assessments from 1989 and 1991.  Although evaluation of these historical biological assessments suggest an impairment of the aquatic life uses (see assessment for the 1998 report above), the assessments are too old (greater than five years) to accurately characterize current conditions of the stream.   This stream reach has a history of fish kills (see assessment for the 1996 report above).   During the October 1997-September 1999 biennial period, a fish kill was reported on July 22, 1998, near New Vienna in Dubuque County.   The kill was attributed to runoff of animal waste; an estimated 34,300 fish were killed over 4.2 miles of this stream.   As noted in the previous assessments (see above), fish kills also occurred in this reach in June 1995 and August 1996.   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 for the Class B(LR) aquatic life uses remains "partially supported" due to reoccurring fish kills.