Dealing with Sediment: Effects on Dams and Hydropower Generation

How do reservoir sedimentation and appropriate management techniques affect operations of dams and hydroelectric facilities? The authors cover the topic and provide illustrative case studies, including the 2,100 MW Aswan High Dam in Egypt.

By Greg Schellenberg, C. Richard Donnelly, Charles Holder and Rajib Ahsan

Although sedimentation of the world’s reservoirs represents a serious threat to the sustainability of hydropower, there is limited guidance on how best to address the problem. Sedimentation affects the safety of dams and reduces energy production, storage, discharge capacity and flood attenuation capabilities. It increases loads on the dam and gates, damages mechanical equipment and creates a wide range of environmental impacts. This article explores sedimentation issues as they pertain to hydropower facilities, dam safety and the environment; discusses sedimentation management techniques; and describes how they can be implemented to limit the impacts on hydropower.


Reservoir sedimentation is a process of erosion, entrainment, transportation, deposition and compaction of sediment carried into reservoirs formed and contained by dams. In unregulated, mature rivers with stable catchments, sediment processes are relatively balanced. Construction of a dam decreases flow velocities, initiating or accelerating sedimentation,1 resulting in progressively finer materials being deposited.

Read the entire HRW Hydro Review Worldwide article here.