Assessment Comments
Assessment is based on (1) surveys of Nebraska fisheries biologists and consultation with IDNR staff and (2) results of U.S. EPA/IDNR fish tissue (RAFT) monitoring in 1998.
Basis for Assessment
[Note: For the 2002 report, the previous waterbody segment for the Missouri River (IA 06-WEM-0040-0), which extended 63 miles from the Little Sioux River to the Big Sioux River, was split into three subsegments: (1) Little Sioux River to Elm Creek near Decatur, NE (near Onawa in Monona Co.) (IA 06-WEM-0040-1), (2) Elm Creek to Omaha Creek Ditch near Homer, NE (near Salix in Woodbury Co.) (IA 06-WEM-0040-2), and (3) Omaha Creek Ditch to the Big Sioux River at Sioux City, Woodbury County. (IA 06-WEM-0040-3 - this one). See subsegment IA 06-WEM-0040_1 for previous Section 305(b) assessments of the original 63-mile river segment of the Missouri River.]
SUMMARY: The Class A (primary contact recreation) uses remain "not assessed" due to the lack of water quality information upon which to base an assessment. The Class B(WW) aquatic life uses remain assessed (evaluated) as "partially supported" based on information from local fisheries biologists on impacts related to flow modification and habitat alterations in this segment of the Missouri River. The fish consumption uses are assessed (monitored) as "fully supported" based on results of fish contaminant monitoring in 1998. The sources of information for this assessment include (1) results of U.S. EPA/IDNR fish tissue monitoring near Sergeant Bluff in 1998 and (2) information from Nebraska fisheries biologists.
EXPLANATION: The Class A uses remained "not assessed" due to the lack of monitoring data for indicator bacteria for this reach of the Missouri River.
The Class B(WW) uses remain assessed (evaluated) as "partially supported" based on the assessment developed for the 1998, 2000, and 2002 reports (i.e., habitat alterations and flow modifications that resulted from development of the river for navigation uses in the mid-Twentieth Century). This assessment was developed in consultation with the Missouri River fisheries biologist for the state of Nebraska.
Fish consumption uses are assessed (monitored) as "fully supported" based on results of U.S. EPA / IDNR fish tissue (RAFT) monitoring in 1998 near Sergeant Bluff in Woodbury County. Levels of all contaminants were less than ½ of the respective FDA action levels and DNR levels of concern in the composite samples of fillets from common carp and freshwater drum. Levels of contaminants were unusually low in these samples, with 20 of 23 contaminants below their analytical detection levels. (see the assessment developed for the 2000 reporting cycle for more information).
