Assessing hydrological response to future climate change in a small Mediterranean watershed (North-Algeria)

This study aims to analyse the impacts of climate change on the hydrological response of the upper basin of Oued El Harrach. Rainfall and temperature outputs of the RCA4 model, forced by the global circulation model MPI-ESM-LR, were used to evaluate future changes. The GR2M hydrological model was used to reproduce future streamflow of the basin for a mid-future (2041–2070) and far-future (2070–2100) period under two representative concentration pathways RCP4.5 and RCP8.5 emission scenarios. Bias correction methods were used to improve hydrological simulations. The findings shown that, future changes in precipitation and temperature affect negatively streamflow, across the basin. An increase in temperature (from 1.3°C to 3.9°C) coupled with a decrease in precipitation (from −17% to −42% in wet seasons) is expected to lead to a significant decline in streamflow. Projected streamflow will change from −75% to +44% in autumn, from −26% to −67% in winter, from −6% to −47% in spring and from −37% to −80% in summer. The future changes in flows are depending on the emission scenarios, the bias correction methods and the projected period. Analysing future hydrological behaviour of the basin will help authorities understand climate change impacts on water resources, guiding sustainable water and agriculture strategies.