Projected Changes in Meteorological Drought in Kucuk Menderes River Basin: A Basin-Scale Spatio-Temporal Assessment

Drought is a natural disaster that has significant effects on many issues from the past to the present in the geography where Turkey is located. It is important to know the temporal and spatial change of drought in issues such as the protection of water resources and watershed management in agriculturally important areas such as Kucuk Menderes Basin. In fact, the negative effects of drought have started to be felt especially by those working in the agricultural sector in the basin. The main objective of this study is to determine the predicted changes related to meteorological drought in the future years by using climate change scenarios in the Kucuk Menderes Basin which is an important agricultural area. For this purpose, monthly mean temperature and monthly total precipitation data of Cesme, Selcuk, Kusadasi, Odemis, Izmir (Bolge) weather stations were used. Furthermore, HadGEM2-ES, MPI-ESM-MR and GFDL-ESM2M global climate models' 1971-2000 reference period and 2016-2099 climate projection two different scenarios (RCP4.5 and RCP8.5) data were obtained from the General Directorate of Meteorology as monthly mean temperature and monthly total precipitation for the region covering the Kucuk Menderes Basin. First of all, error values were calculated by using the reference period data of the models and the observation data of the weather stations in the study area. As a result of the error analysis, rough resolution results of future period RCP 4.5 and RCP 8.5 scenarios of the HadGEM2-ES model, which was found to be the most suitable model for the study area, were evaluated in periods covering 2016-2040, 2041-2070 and 2071-2099. The Bagnouls Gaussen drought index, which is the most suitable for the data set we have and has been used in many studies in the Mediterranean Basin, was used for drought analysis. It was determined that drought values would increase between periods according to both scenarios, especially in the eastern part of the basin, the most important part in terms of agriculture. These changes in drought will have effects on agriculture, basin management, conservation of water resources and ecology. Unconscious consumption of groundwater in the basin will become a more significant problem in the future with the growing effects of drought. These effects should be taken into consideration in all planning efforts to be made related to the basin.