Operation of multiple reservoir systems to control sedimentation in rivers and reservoirs

A new methodology is presented for determination of optimal reservoir management strategies that minimize sediment scour and deposition in multiple-reservoir river networks. Consideration is given to adverse effects of sedimentation occurring in both reservoirs and rivers of an alluvial network. The problem is formulated as a discrete-time optimal control problem in which a successive approximation linear quadratic regulator (SALQR) optimization algorithm is interfaced with the U.S. Army Corps of Engineers HEC-6 sediment transport simulator. The simulation model is used to evaluate open channel flow hydraulics and sediment transport dynamics, while the optimization module strategically updates reservoir operation policies and solves the augmented control problem. System operating constraints imposed on stagewise reservoir releases and storage levels are incorporated into the objective function using a quadratic loss penalty function. The model can be used to minimize scour and deposition through an entire network or only at specified locations, and can be used to evaluate policies that alternatively maximize sedimentation. Capabilities of the model are demonstrated through applications to a hypothetical three-reservoir river network and the Yazoo Basin river-reservoir network in Mississippi. The resulting methodology serves as an effective decision support mechanism that can be used in the sustainability of rivers and reservoirs, as well as their associated benefits.