Management of Water Reservoirs (Embungs) in West Timor, Indonesia

Communal water storage reservoirs (embungs) that serve many villages in West Timor, Indonesia, during the prolonged annual dry season are plagued with sedimentation problems. Sedimentation progressively reduces water storage capacity, and consequently the benefits that community can derive from embungs. This paper investigates four alternative strategies for managing the sedimentation of a typical village embung: (1) current management (a "no management" situation), (2) soil conservation in the embung catchment, (3) periodic sediment removal and (4) a combination of soil conservation and sediment removal. Without periodic sediment removal, an embung has a finite life dependent on the rate of sedimentation. The results indicate that periodic cleaning is worthwhile. Strategy (4) gives the highest net present value followed by strategy (3). The study shows that the current "no management" strategy is the worst strategy. Sensitivity analyses were conducted to investigate how robust the ranking is to alternative discount rates and to assumed effectiveness of soil conservation measures in reducing sedimentation.