Iowa DNR
Iowa DNR
ADBNet
Water Quality Assessments
Impaired Waters List

Raccoon River IA 04-RAC-1116

mouth (at Des Moines Polk Co.) to the Polk/Dallas county line

Assessment Cycle
1996
Result Period
1992 - 1994
Designations
Assessment Type
Monitored
Integrated Report
Category 0
Legacy ADBCode
IA 04-RAC-0010_1
Overall Use Support
Not supporting
Aquatic Life Use Support
Threatened
Fish Consumption
Not assessed
Primary Contact Recreation
Not supporting
Drinking Water
Partial
Documentation
Assessment Comments

Assessment is based on ambient monitoring by Des Moines Water Works and IDNR city monitoring.

Basis for Assessment

Had 14 of 18 non runoff-affected samples in violation of Class A WQ criterion (=78% viol =NS).   Only violations of Class B WQ criteria was mercury:  6 of 9 samples collected over 3 years exceeded the Class B WQ criterion (= 67% viol).   Due to problems with mercury analysis, and due to recommend in 305(b) guidelines (1996: 5-18) regarding reliability of toxics data < 1 ppb., these violations are not considered in the assessment.   Thus, Class B uses assessed as FST due to presumed impacts from NPS.   For Class C use, 14 of 68 samples had NO3 > 10 mg/l (= 20% viol).  Although both mean (7.45 mg/l) and median (7.5 mg/l) levels of NO3 were < 10 mg/l, assess as PS due to installation of nitrate removal system by DM W.Works.