HR: 10:35h
AN: H52A-02    [Abstracts]
TI: Rehabilitation Experiments in the Context of Adaptive Management, Lower Missouri River
AU: * Jacobson, R B
EM: rjacobson@usgs.gov
AF: US Geological Survey - CERC, 4200 New Haven Road, Columbia, MO 65201 United States
AU: Gaeuman, D A
EM: dgaeuman@usgs.gov
AF: US Geological Survey - CERC, 4200 New Haven Road, Columbia, MO 65201 United States
AU: Elliott, C M
EM: celliott@usgs.gov
AF: US Geological Survey - CERC, 4200 New Haven Road, Columbia, MO 65201 United States
AU: Johnson, H E
EM: haljohnson@usgs.gov
AF: US Geological Survey - CERC, 4200 New Haven Road, Columbia, MO 65201 United States
AU: Laustrup, M S
EM: mlaustrup@usgs.gov
AF: US Geological Survey - CERC, 4200 New Haven Road, Columbia, MO 65201 United States
AB: Morphology of the highly engineered Lower Missouri River (Sioux City, Iowa to St. Louis, Missouri) is nearly independent of flow regime because channelization has greatly reduced opportunity for channel adjustment. Rehabilitation efforts have therefore focused on altering channel form directly rather than altering flow regime. Rehabilitation sites offer the potential for experimental studies to address geomorphic adjustments and tradeoffs in form and flow in river recovery. Implementation of experiments remains a challenge, however, because increased scientific understanding is not universally valued by all stakeholders participating in the adaptive management process. Nevertheless, some rehabilitation sites have been utilized for opportunistic geomorphic experiments. Engineered rehabilitation projects typically seek to increase diversity of habitats, with emphasis on increasing areas of shallow, slow current velocity that are much diminished from their historical extent and which are thought to be especially important to recovering ecological processes. Projects fall into two broad categories: those that increase width of the channel or diversity of habitats between the high banks, and those that create or re-create side-channel chutes. Early results from two contrasting experiments in side-channel chute development indicate that a) the experimentally uncontrolled sequence and magnitude of hydroclimatic events have a substantial effect on morphogenesis, and b) geomorphic and ecological responses are highly influenced by reach-scale spatial patterns of sediment and large-woody debris transport that determine fluxes into chutes. After less than a year of monitoring of channel-widening experiments, we have only preliminary results, but we have developed a keen appreciation for experimental approaches in an extremely dynamic and spatially diverse river. Particular challenges are developing robust, cost-effective, geomorphic performance metrics and designing experiments where replicates cannot be defined and management timeframes are short relative to timeframes of geomorphic processes.
DE: 6329 Project evaluation
DE: 1803 Anthropogenic effects
DE: 1815 Erosion and sedimentation
DE: 0400 Biogeosciences
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting