Sediment inflow and deposition depletes much required storage capacity, decreases the useful life, and alters the beneficial uses of dam reservoirs.  This research was carried out to estimate the useful life of the Gurara dam reservoir to improve the effective operation and management of the Gurara dam reservoir.  The results of 2018 total annual fluvial sediment inflow into Gurara dam reservoir, trap efficiency, Capacity Inflow ratio (C/I), Capacity sediment density and other empirical approaches were used.  The Gurara dam started operating in 2007.  No detailed study was yet carried out to assess its useful life.  The result shows approximately that the useful life of the Gurara dam reservoir is about 165 years.  The estimated useful life of 165 years is feasible since the watershed has good vegetation cover, plenty of rocks on its upper watershed.  Integrated watershed management, good environmental practices in agriculture are the Engineering measures recommended as actions to be taken for the sustainability of the Gurara watershed.