Global Change Scenarios in the Prediction of Reservoir Sedimentation and Water Availability

The goal of this research is to analyse sedimentation and resulting water availability reduction in reservoirs from a tropical sub-humid environment, using the case study of the Acarape do Meio Reservoir, located in Ceara (Brazil). The simulation considers four reference scenarios: two climatic and two macroeconomic. The lumped HIDROSED model was applied to the 208.2 km² Acarape catchment for a simulation period of 50 years (2001–2050) to quantify sediment yield and deposition in the reservoir. The results show that reservoir sedimentation varies from 4.17 to 9.58 million tons, depending on the scenario. This implies a reduction of water availability (with 90% reliability level) ranging from 5.6 Mm³ year⁻¹ to 0.4 Mm³ year⁻¹ (38% to 3%, respectively) in five decades. The research concludes that the reservoir sedimentation processes are more strongly affected by soil use than by climatic changes.