Winnebago River IA 02-WIN-827

Assessment Comments

Assessment is based on two water quality studies conducted for Lehigh Cement Co. in 1994-95.

Basis for Assessment

SUMMARY:  The Class B(WW) aquatic life uses remain assessed as "fully supported / threatened."  The fish consumption uses remain "not assessed."  EXPLANATION:  The DNR quarterly water quality monitoring station at Mason City was last monitored from October 1991 to September 1993.   Results from this monitoring are now considered too old (greater than five years) for assessing current water quality conditions.   As part of DNR's expanded water quality monitoring program, however, monthly monitoring at the Mason City station began in October 1999.   Results from this monitoring will allow development of an updated assessment of support of beneficial uses for the 2002 report.   Thus, for the 2000 report, continue to use the assessment of support of the Class B(WW) uses developed for the 1998 report (see above).   This assessment was based on results of water quality studies conducted in 1994 and 1995 by the University of Iowa Hygienic Laboratory for the Lehigh Portland Cement Company.   Results from these studies are approximately 5 years old and thus can be used to assess current water quality conditions.   As stated in the assessment for the 1998 report (above), results of these studies suggest a potential water quality problem; follow-up  monitoring is needed to better determine the status of the aquatic  communities of this reach of the Winnebago River and to determine whether the Class B(WW) uses may be impaired.   Fish consumption remained "not assessed" due to a lack of recent fish tissue monitoring in this river reach.