Author(s): W. Stancill; Dr. S. Kenner
Linked Author(s):
Keywords: No Keywords
Abstract: The historic Missouri River was characterized by a diverse landscape including braided channels, chutes, islands, sand bars, shallow backwaters and riparian floodplains. Construction and operation of the six main-stem Missouri River dams and channelization of the lower one-third of the river contributed to habitat loss that is implicated in the decline of fish and wildlife now listed as threatened or endangered. An independent science review of the United States Army Corp of Engineers' Missouri River Recovery Program resulted in recommendations that included conducting hydraulic simulations to evaluate habitat assessment and monitoring programs and guide habitat restoration efforts. The RMA2 hydraulic model was applied to a relatively unaltered stretch of the Missouri River to gain insight into the model's utility for simulating hydraulic characteristics in a complex natural setting. Three numerical meshes of increasing resolution were evaluated for model simulations. High resolution (fine scale) meshes improved agreement between simulated and field-measured bathymetry but also contributed to numerical instabilities related to complex wetting and drying fronts throughout topographically and bathymetrically complex sand bars and sidechannels. Based on agreement between simulated and field collected measurements (i.e., model calibration) and conservation of mass in numerical simulations, the RMA2 hydraulic model's performance was encouraging. Sparse data collection transects, in locations with complex terrain and bathymetry, and misaligned transects relative to flow direction required reinterpretation of bathymetry contours during model construction. Unique hydraulic variable assignments for habitats not in close proximity to banklines indicate RMA2 is well suited for ecological investigations involving mid-channel habitats but maybe limited for near shore investigations.
Year: 2009