Investigation of the effects of drought on agricultural activities: A vulnerability study in the Seyhan Basin

Climate change caused by environmental problems affects human life in many aspects. One of the sectors most affected by this situation is the agricultural sector. Within the scope of this thesis study, an agricultural vulnerability research was conducted in the Seyhan Basin, one of the river basins of Turkey, to determine the impact of meteorological drought on the agricultural sector. The subcomponents were created by using the precipitation and temperature data of meteorological stations and the HadGEM2-ES/RegCM4.3 climate projection model with the results of survey studies conducted with farmers in the Seyhan Basin. In determining meteorological drought, the dry months in a 6-month period of 30 years were obtained using the standard precipitation index (SPI) method. In this context, the Principal Components Analysis (PCA) Method was used to determine the sub-components that are effective in the formation of vulnerability and to compare the sub-basins. According to the results, the number of dry months, the number of warm months above average and average Normalized Difference Vegetation Index (NDVI) values expressing vegetation density were found to be the most effective subcomponents. Considering the index values determined by the PCA method, Lower Seyhan Basin sub-basin was more exposed to meteorological drought and had a large vegetation cover due to agricultural activities which increased its sensitivity to drought and led to an increase in the level of its vulnerability. Besides, the distribution of agricultural vulnerability showed heterogeneity, particularly due to the presence of regions with different sensitivity and adaptability within the Seyhan Dam-Zamantı Göksu Junction Area (SZGBY) and Zamantı River sub-basins. Moreover, PCA results of exposure for the next period shows that the exposure levels of almost all regions would increase. The main reason is that the HadGEM2-ES/RegCM4.3 regional climate model predicts temperature values high and precipitation values low for all sub-basins. Considering all these results and findings, they serve as a guide for regional studies on meteorological drought and its effects. In addition, the meteorological drought forecast results obtained using HadGEM2-ES/RegCM4.3 regional climate model outputs are expected to contribute to the emergency action plans by the responsible units for the Seyhan Basin. Keywords: Meteorological Drought, Vulnerability, Principal Components Analysis, Agricultural Activities