Des Moines River IA 04-LDM-1011
from Ottumwa dam (S24 T72N R14W Wapello Co.) to confluence with Cedar Cr in S33 T75N R17W Mahaska Co.
Assessment Comments
Basis for Assessment
SUMMARY: Continue to consider support of the Class A (primary contact recreation) uses, the Class B(WW) aquatic life uses, and fish consumption uses to be "not assessed." Support of the Class C (drinking water) uses were assessed as "partially supported." EXPLANATION: Insufficient water quality monitoring information is available for this river reach upon which to base an assessment of support of either the Class A (primary contact recreation) uses, the Class B(WW) aquatic life uses, or the fish consumption uses. Data from the DNR quarterly WQ monitoring station at Ottumwa are (1) too old (greater than five years) to be useful for developing water quality assessments of current conditions and (2) influenced by urban activities and thus do not likely reflect water quality conditions upstream from the city. Used information from the DNR Water Supply Section, however, to assess support of the Class C (drinking water) uses as partially supported (=PS) due to issuance by Cargill Inc. (Eddyville) of a notice of an MCL violation for nitrate on June 11, 1998. According to EPA and DNR methods for assessing support of Class C (drinking water) uses, one or more drinking water advisory lasting 30 days or less per year suggests that the Class C use is only partially supported (see pages 3-38 to 3-44 of U.S. EPA 1997b and the DNR assessment methodology for Section 305(b) reporting).