Hydrological impacts of climate change in northern Tunisia

Tunisia is a water-stressed country, which derives most of its surface water from its northern regions. Given Northern Tunisia’s role as a water provider, this study investigated the hydrological impacts of climate change on five catchments located in this region. Three hydrological models are considered: HBV, GR4, andIHACRES. Climate projections were derived from eleven high-resolution EURO-CORDEX regional climate models (forced by general circulation models; GCM-RCMs). A quantile mapping (QM) bias correction method was applied to correct the climate simulations. Historical streamflow simulations (1970–2000), achieved by forcing the hydrological models with GCM-RCM precipitation and temperature, were first assessed in order to select the most realistic GCM-RCMs for future projections. The remaining bias corrected GCM-RCMs were then used to force the hydrological models in order to achieve projections of streamflow. The evaluation of the stream-flow projections was conducted over two time periods(i) mid-term: 2040–2070 and (ii) long-term: 2070–2100 to identify the magnitude of the projected change of streamflow under the climate scenarios RCP 4.5 and RCP8.5. The hydrological projections were analyzed according to several metrics commonly used by water managers.