OPTIMIZATION MODELING FOR SEDIMENTATION IN ALLUVIAL RIVERS

Mathematical models are developed for determining optimum reservoir re leases in order to minimize the aggradation and degradation in downstr eam river reaches. The physical system is composed of a reservoir-rive r interaction in which the releases from the reservoir comprise the in flows for the downstream river reach. A finite-difference scheme of se diment routing is adopted to determine the changes of bed profile alon g the river. The nonlinear programming problem is solved using a nonli near programming solver, a dynamic programming (DP) procedure, and a d ifferential dynamic programming (DDP) procedure. Four sediment transpo rt functions have been used in order to evaluate and test the validity of the formulation. Chance-constrained formulations are also presente d to consider the uncertainties of sediment transport parameters used in the modeling. A rectangular channel is used for the purpose of illu strating the procedure, which is a preliminary step toward the applica tion of the methodology to a large existing system.