RESERVOIR SEDIMENTATION

RESERVOIR SEDIMENTATION
The erosion and transport of sediment by water is a key process in shaping a river basin and has important economic and environmental consequences. Predicting rates of erosion and transport of sediment and its deposition on the floodplains or in reservoirs, lakes and estuaries is one of the tasks of the hydrologist.
The rate at which the capacity of a reservoir is reduced by sedimentations depends on:
1- The quantities of sediment inflow.
2- The percentage of this inflow trapped in the reservoir.
3- The density of the deposited sediment.
The quantity of sediment inflow may be estimated by Fleming equation.
Brune derived a relationship between reservoir trap efficiency, the percent of incoming sediment retained in the reservoir, and the ratio of reservoir capacity to mean annual water inflow.
The volume occupied by the sediment in the reservoir will be depending on the specific weight of the deposited material. The specific weight varies with the kind of sediment and the age of the deposits. Older sediment has more time to consolidate and is under a superimposed load from the more recent deposits.