Climatic change impact and associated uncertainty on catchment hydrology: a case study on the Chiba catchment in Tunisia

Sellami, Haykel [Centre de Rech. et Technol.Eaux, Soliman, Tunisia] Benabdallah, Sihem [Centre de Rech. et Technol.Eaux, Soliman, Tunisia] Vanclooster, Marnik [UCL]

Projected changes in climate and their possible impacts on river flow are of concern for sustainable management of the water resources in Tunisia. Most of the climate model (CM) projections available so far suggest a decrease in precipitation and increase in temperature over the country in the future (next 25 to 50 years). These changes are expected to alter the catchment flow regime with exacerbated threats on the available water resources, yet limited and scarce. Surprisingly, there are few studies that quantify the impacts of climatic change on the catchment hydrology in Tunisia. One possible reason could be related to the inherent uncertainty in CM projection. Therefore, we here present a modelling approach that combines an ensemble of 4 CM projection to force the Soil and Water Assessment Tool (SWAT) physically based hydrological model for assessing changes and uncertainty in the hydrology of the Chiba catchment (North-East Tunisia) related to climatic change. Results indicate that the catchment is likely to experience drier conditions in the horizon 2050s facing a reduction in monthly flow magnitude, soil moisture conditions and water availability which is likely to be more pronounced in the dry season than in the rainy season.