East Fork Des Moines River IA 04-EDM-970

Assessment Comments

Assessment is based on results of IDNR monthly ambient monitoring 1 mile N of St. Joseph, Kossuth Co.

Basis for Assessment

SUMMARY:  Assessed support of the Class A (primary contact recreation) uses as "fully supported/threatened;" support of the Class B(WW) aquatic life uses was assessed as "fully supported."  Support of fish consumption uses was changed from  "fully supported" to "not assessed."  EXPLANATION:  Results of DNR monthly monitoring near St.  Joseph in 1998-99 showed that less than 10 samples (8 of 14) collected during summer periods of the 1998-99 biennial period and analyzed for levels of fecal coliform bacteria were not materially affected by surface runoff.   Thus, according to DNR's assessment methodology for Section 305(b) reporting, the assessment type for the Class A primary contact uses becomes "evaluated" (versus "monitored").   The geometric mean of fecal coliform bacteria in the eight non-runoff-affected samples (169 orgs/100) ml was less than the WQ criterion of 200 orgs/100 ml, thus suggesting full support of the primary contact recreation uses.   Because one of the eight samples contained a level of fecal coliforms greater than U.S.  EPA's recommended single sample maximum density of 400 orgs/100 ml, the level of support of the Class A uses was assessed as "fully supporting / threatened."  Results of monitoring during the biennial period show no violations of Class B(WW) (aquatic life) water quality criteria in the 24 samples analyzed for dissolved oxygen, pH, and ammonia, and in the one sample analyzed for toxic metals; thus, the aquatic life uses were assessed as "fully supported."  The support of fish consumption uses was changed from "fully supported" to "not assessed."  The 1995 EPA/DNR fish tissue (RAFT) sampling near Algona was conducted  approximately 20 miles upstream from this waterbody segment.   The extrapolation of the results from the 1995 sampling to this downstream assessment segment is not justified.