Computer-Based Prognosis of Missouri River Bed Degradation: Refinement of Computational Procedures

摘要

Computational procedures in the IALLUVIAL numerical model have been refined and streamlined. IALLUVIAL computes alluvial river-bed evolution subject to varying water and sediment inflow, considering nonuniform sediment, armoring, sorting, and transport-dependent flow resistance. Previous application of IALLUVIAL to the Missouri River had brought out problems related to: excessive computation time; singular behavior at the upstream model limit; and distortion of bed-perturbation propagation speed. The report reviews the basis of IALLUVIAL, describes in detail the basis and implementation of the various modifications adapted, and reports on several computations of bed evolution in the Missouri River between Omaha and Sioux City.