Iowa River IA 02-IOW-641

Assessment Comments

Assessment is based on results of IDNR ambient monthly monitoring downstream from Marshalltown.

Basis for Assessment

SUMMARY:  The Class A (primary contact recreation) uses remain assessed as "partially supported," and the Class B(WW) aquatic life uses remain assessed as "fully supported / threatened."  Fish consumption uses remain "not assessed."  EXPLANATION:  Due to the absence of recent water quality information, continued to use the assessments of support of the Class A and Class B(WW) uses developed for the 1998 report (see above).   These assessments were based on results of water quality monitoring during the 1996-1997 biennial period from the DNR quarterly monitoring station at Marshalltown.   Results from stations monitored monthly or more frequently, however, are preferred for Section 305(b) assessments in order to improve the accuracy and confidence level of the assessment.   As part of DNR's expanded water quality monitoring program, monthly monitoring at the Marshalltown station began in October 1999.   The fish consumption uses remained "not assessed" due to a lack of recent fish tissue monitoring in this river reach.