SIGNIFICANCE AND SUSTAINABILITY OF FRESHWATER RESERVOIRS: CASE STUDY OF TARBELA DAM, PAKISTAN

Importance of reservoirs for supplying fresh water has increased significantly at present. In order to move a step forward towards making the present day un-sustainable reservoirs into sustainable infrastructure, this article reviews the sediment erosion and reservoir sedimentation estimates at global scale and applies the Reservoir Conservation Tool (RESCON) for one of the large reservoirs: Tarbela Dam in Pakistan. The article points out the wide variations of the estimates both for soil erosion and reservoir sedimentation and shows how the various reservoir level and duration of flushing will affect in achieving the sediment balance ratio in the Tarbela reservoir. It is found that the flushing can be done efficiently with Sediment Balance Ratio (SBR) greater than 1. The long term sustainable capacity of the reservoir is about 27% with respect to its original capacity.