Iowa DNR
Iowa DNR
ADBNet
Water Quality Assessments
Impaired Waters List

Missouri River IA 06-WEM-1722

from confluence with Omaha Creek Ditch (SW 1/4 S6 T86N R47W Woodbury Co. at river mile 715.8 (near Browns Lake)) to confluence with Big Sioux R. at river mile 734.0 at Sioux City Woodbury Co.

Assessment Cycle
2002
Result Period
1998 - 2000
Designations
Assessment Methodology
Assessment Type
Evaluated
Integrated Report
Category 0
Legacy ADBCode
IA 06-WEM-0040_3
Overall Use Support
Partial
Aquatic Life Use Support
Partial
Fish Consumption
Fully
Primary Contact Recreation
Not assessed
Documentation
Assessment Comments

Assessment is based on (1) surveys of Nebraska fisheries biologists, (2) consultation with DNR staff, and (3) 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."  The Class B(WW) aquatic life uses remain assessed as "partially supported."  The fish consumption uses are assessed as "fully supported."  EXPLANATION:  The Class A uses remain "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 as "partially supported" based on the assessment developed for the 1998 and 2000 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 remain assessed as "fully supported" based on EPA/DNR fish tissue (RAFT) monitoring near Sergeant Bluff in Woodbury County in 1998.

Monitoring and Methods
Assessment Key Dates
8/12/1998 Fish Tissue Monitoring
Methods
120 Surveys of fish and game biologists/other professionals
260 Fish tissue analysis
Monitoring Levels
Biological 0
Habitat 0
Physical Chemistry 0
Toxic 0
Pathogen Indicators 0
Other Health Indicators 0
Other Aquatic Life Indicators 0
# of Bio Sites 0
BioIntegrity N/A
Causes and Sources of Impairment
Causes Use Support Cause Magnitude Sources Source Magnitude
Flow alteration Overall Use Support Moderate
  • Flow Regulation/Modification
  • Moderate
Other habitat alterations Overall Use Support Moderate
  • Channelization
  • Moderate