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Streamflow, Sediment Transport, and Geomorphic Change during the 2011 Flood on the Missouri River Near Bismarck–Mandan, ND
Author(s) -
Nustad Rochelle A.,
Benthem Adam J.,
Skalak Katherine J.,
McDonald Richard R.,
Schenk Edward R.,
Galloway Joel M.
Publication year - 2018
Publication title -
jawra journal of the american water resources association
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.957
H-Index - 105
eISSN - 1752-1688
pISSN - 1093-474X
DOI - 10.1111/1752-1688.12678
Subject(s) - hydrology (agriculture) , geology , flood myth , sediment transport , streamflow , sedimentary budget , channel (broadcasting) , hyperconcentrated flow , bank erosion , sediment , erosion , deposition (geology) , environmental science , geomorphology , drainage basin , bed load , geography , geotechnical engineering , cartography , archaeology , engineering , electrical engineering
Geomorphic change from extreme events in large managed rivers has implications for river management. A steady‐state, quasi‐three‐dimensional hydrodynamic model was applied to a 29‐km reach of the Missouri River using 2011 flood data. Model results for an extreme flow (500‐year recurrence interval [RI]) and an elevated managed flow (75‐year RI) were used to assess sediment mobility through examination of the spatial distribution of boundary or bed shear stress ( τ b ) and longitudinal patterns of average τ b , velocity, and kurtosis of τ b . Kurtosis of τ b was used as an indicator of planform channel complexity and can be applied to other river systems. From differences in longitudinal patterns of sediment mobility for the two flows we can infer: (1) under extreme flow, the channel behaves as a single‐thread channel controlled primarily by flow, which enhances the meander pattern; (2) under elevated managed flows, the channel behaves as multithread channel controlled by the interaction of flow with bed and channel topography, resulting in a more complex channel; and (3) for both flows, the model reach lacks a consistent pattern of deposition or erosion, which indicates migration of areas of erosion and deposition within the reach. Despite caveats and limitations, the analysis provides useful information about geomorphic change under extreme flow and potential implications for river management. Although a 500‐year RI is rare, extreme hydrologic events such as this are predicted to increase in frequency.