HR: 14:30h
AN: NB23C-04 INVITED     [Abstracts]
TI: Process and Prospects for the Designed Hydrograph, Lower Missouri River
AU: * Jacobson, R B
EM: rjacobson@usgs.gov
AF: US Geological Survey, 4200 New Haven Road, Columbia, MO 65201 United States
AU: Galat, D L
EM: galatd@missouri.edu
AF: US Geological Survey Cooperative Research Unit, 301 ABNR University of Missouri, Columbia, MO 65211 United States
AU: Hay, C H
EM: chay1@unlserve.unl.edu
AF: Department of Biological Systems Engineering, University of Nebraska-Lincoln, Lincoln, NE 68583 United States
AB: The flow regime of the Lower Missouri River (LMOR, Gavins Point, SD to St. Louis, MO) is being redesigned to restore elements of natural variability while maintaining project purposes such as power production, flood control, water supply, and navigation. Presently, an experimental hydrograph alteration is planned for Spring, 2006. Similar to many large, multi-purpose rivers, the ongoing design process involves negotiation among many management and stakeholder groups. The negotiated process has simplified the hydrograph into two key elements -- the spring rise and the summer low - with emphasis on the influence of these elements on three threatened or endangered species. The spring rise has been hypothesized to perform three functions: build sandbars for nesting of the interior least tern and piping plover, provide episodic connectivity with low-lying flood plain, and provide a behavioral spawning cue for the pallid sturgeon. Among these, most emphasis has been placed on the spawning cue because concerns about downstream flood hazards have limited flow magnitudes to those that are thought to be geomorphically ineffective, and channelization and incision provide little opportunity for moderate flows to connect to the flood plain. Our analysis of the natural hydrologic regime provides some insight into possible spring rise design elements, including timing, rate of rise and fall, and length of spring flow pulses. The summer low has been hypothesized to emerge sandbars for nesting and to maximize area of shallow, slow water for rearing of larval and juvenile fish. Re-engineering of the navigation channel to provide greater diversity of habitat during navigation flows has been offered as an alternative to the summer low. Our analysis indicates that re-engineering has potential to increase habitat availability substantially, but the ecological results are so-far unknown. The designed hydrograph that emerges from the multi-objective process will likely represent a compromise of many values and is unlikely to bear close resemblance to the natural hydrograph. Nonetheless, the hydrograph will provide an essential first step in experimentation and adaptive management of the Lower Missouri River.
DE: 0400 Biogeosciences
DE: 1803 Anthropogenic effects
DE: 1815 Erosion and sedimentation
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly