Missouri River IA 06-WEM-1720

Assessment Comments

Assessment is based on (1) information from Nebraska fisheries biologists on habitat conditions in the Missouri River and (2) assessment information from Nebraska DEQ’s 2008 Integrated Report.

Basis for Assessment

SUMMARY:  The Class A1 (primary contact recreation) uses are assessed (monitored) as “fully supported” based on data and information from the Nebraska DEQ.   The Class B(WW1) 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 remain “not assessed” due to the lack of fish contaminant monitoring in this river segment.   The sources of information for this assessment are (1) information from Nebraska fisheries biologists on habitat conditions in the Missouri River and (2) assessment information from Nebraska DEQ’s 2008 Integrated Report (http://www.deq.state.ne.us/).    

EXPLANATION:  The Class A1 (primary contact recreation) uses are assessed (monitored) as “fully supported” based on the assessment of primary contact recreation uses identified for this segment of the Missouri River by the Nebraska Department of Environmental Quality (NDEQ) for their 2006 and 2008 Section 303(d) listing cycles.   This assessment represents a de-listing of Iowa’s 2006 bacteria impairment for this assessment segment.   The rationale for this delisting is as follows.   A draft version of Nebraska’s 2006 Integrated Report stated that the recreation uses of this segment of the Missouri River (NDEQ MT1-10000) were impaired due to high levels of indicator bacteria.   Based on this information, Iowa DNR mistakenly placed this impairment on its 2006 Section 303(d) list.   According to staff of the Nebraska DEQ, however, this impairment was de-listed during Nebraska’s 2006 Integrated Reporting cycle:  samples of E.  coli collected from this segment of the Missouri River in 2005 yielded a recreation season geometric mean of 72 orgs/100 ml (N=22), indicating that the bacterial impairment should be de-listed.   Nebraska’s 2008 Integrated Report also shows that recreation uses for Missouri River segment MT1-10000 are fully supported.   Thus Iowa DNR is de-listing this impairment for the current (2008) Integrated Reporting cycle.  

The Class B(WW1) uses remain assessed 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 remain “not assessed” due to the lack of recent fish contaminant monitoring in this river segment.