The most important practical and critical problem related to the performance of reservoirs is the estimation of storage capacity loss due to sedimentation process. The problem to be addressed is to estimate the rate of sediment deposition and the period of time at which the sediment would interfere with the useful functioning of a reservoir. Fairly a large number of methods and models are available for the estimation, analysis and prediction of reservoir sedimentation process. However, these methods and models differ greatly in terms of their complexity, inputs and computational requirements. In the present study, the rate of sedimentation and useful life time of a reservoir were estimated using the trap efficiency (Te) approach. The empirical relationship suggested by Brune (1953) to estimate reservoir sediment Te and Gill (1979) approach to estimate useful life of a reservoir are modified to suit Gobindsagar Reservoir (Bhakra Dam) on Satluj River in Bilaspur district, Himachal Pradesh, in the Himalayan region of India.