The effect of climate change on water security: The case study of Susurluk Basin

Climate change and increasing consumption threaten water security with increasing demand for water. Therefore, it is possible to plan for the future and take precautions with blue and green water-based water security (scarcity and vulnerability) calculation. In this study, changes in precipitation, temperature, and water security for the near and far future (2030-2059 and 2070-2099) were analyzed for the Susurluk Basin, dominated by semi-arid Mediterranean climate, compared to the reference period (1979-2014). For this purpose, 14 general circulation models (GCMs) with three socioeconomic pathways (SSP1-2.6, SSP3-7.0, and SSP5-8.5) scenarios were used for statistical downscaling of daily total precipitation, maximum and minimum temperatures for nine meteorological observation stations. Future data were entered into the SWAT hydrological model by averaging the most appropriate four GCMs and multi-model ensemble, and blue and green water parameters were calculated together with water consumption data. According to the results of the study, a decrease of 120 and 250 mm in annual precipitation, a decrease/increase of –4-1.5 to 0 - 4°C in annual maximum temperatures, and a decrease/increase of –1-1 to 1-5°C in annual minimum temperatures are expected in the near and far future. It is predicted that there will be a decrease of 70% and 30% in blue and green water storage, while the values of 30% and 20% in scarcity will increase to 40% in the future. It is also estimated that Bursa and Balıkesir regions will be exposed to blue water scarcity rather than green water in the future.