Sediment flushing from reservoirs: a review

Abstract

Sustainable use of natural resources is of great importance worldwide. For reservoirs, the loss of storage to sedimentation is a major challenge to their sustainable use. Several management options exist that can improve sustainability of reservoirs, one of them is the removal of the accumulated sediment by means of hydraulic flushing. Based on a comprehensive review of literature, this paper presents a review of factors related to feasibility of sediment flushing. These factors have been grouped into seven topics: availability of water for flushing and cost of flushing operations; timing of flushing; limitations posed by reservoir geometry, in particular the width of the reservoir and the presence of bends; the effects of sediment properties; sizing and positioning of evacuation outlets; downstream impacts of flushing and control of operation. For each topic, the technical and environmental issues that arise as well as ways to address them are presented. Some of the factors are competing, which further stresses the need for careful planning and evaluation of flushing operations.