East Fork Des Moines River IA 04-EDM-974

Assessment Comments

Insufficient infformation upon which to base an assessment. Previous assessments based on results of water quality monitoring conducted by the Minnesota Pollution Control Agency near Ceylon, MN, were in error.

Basis for Assessment

[Note:  Prior to the current (2008) Section 305(b) cycle, this stream segment was designated only for Class B(WW) aquatic life uses, including fish consumption uses.   Due to changes in Iowa’s surface water classification that were approved by U.S.  EPA in February 2008 (see http://www.iowadnr.com/water/standards/files/06mar_swc.pdf), this segment is also now presumptively designated for Class A1 (primary contact recreation) uses.   This segment remains designated for warmwater aquatic life use (now termed Class B(WW1) uses), and for fish consumption uses (now termed Class HH (human health/fish consumption uses).]

SUMMARY:  The presumptive Class A1 (primary contact recreation) uses are "not assessed" due to the lack of information upon which to base an assessment.   Similarly, the Class B(WW1) aquatic life uses are not assessed due to the lack of monitoring data or other water quality information upon which to base an assessment.   The 2004 assessment for this segment indicated an impairment of the aquatic life uses due to levels of dissolved oxygen that violated state water quality criteria; this assessments was in error.   Fish consumption uses remain "not assessed" due to the lack of fish contaminant monitoring in this river reach.  

EXPLANATION:  The presumptive primary contact recreation uses, the designated aquatic life uses, and the fish consumption uses for this segment are all considered "not assessed" due to the lack of water quality data or other information upon which to base assessments.   Previous assessments for this segment were erroneously based on results of ambient chemical/physical monitoring from the Minnesota Pollution Control Agency (MPCA) collected NE of Ceylon, MN, approximately four miles north of the Iowa/Minnesota state line.   The previous assessments, however, did not account for the occurrence of Tuttle Lake (2,360 acres) between the MPCA monitoring station and the segment of the East Fork Des Moines River erroneously identified as impaired.   The East Fork Des Moines River flows into, and out of, this relatively large lake, with an estimated seven miles of lake/wetland area between the inflow and outflow.   Thus, the chemical water quality of the river flowing out of the lake likely has no relation to the water quality of the river flowing into the lake.   Due to this error, the 2004 impairment of aquatic life uses due to low dissolved oxygen was removed for the 2006 305(b)/303(d) cycle.