Climate Change Impacts on Hydrological Regimes in Arid and Semi-arid Basins: A Case Study

English Abstract:

Water need for urban water supply is increasing as population is growing in Mediterranean Africa and north of Sahara. Climate changes along with the need for more water for development have direct impacts on rain-fed agriculture and availability of water resources in Tunisia. In semi-arid areas, where variability of precipitation duration and severity are very high and monitoring networks are sparse, the need for weather generators is essential for simulating rainfall-runoff processes. In this study, sensitivity of streamflow regimes and hydrological response of the Sidi Salem Basin (SSB), as the most important catchment in Tunisia are investigated under climate changes. Global climate models’ projections obtained from the Coupled Model Intercomparison Project Phase 5 (CMIP5) for current and future periods are applied to find the change factors for precipitation and air temperature. Then, time series of precipitation and air temperature are generated for control and future periods based on the statistics of the historical data and change factors. Hydrological processes in the SSB are simulated by the Water Evaluation and Planning (WEAP) model. The results show that the streamflow regimes in the SSB are very sensitive to a moderate change in precipitation and warming and a drastic decline in streamflow is expected by the end of 21^st century. The results of this research can be applied in adaptive planning and development strategies.