Exploring the Effect of Meteorological and Hydrological Trends on Groundwater Drought Index: The Case of Seyhan Basin

Understanding the disasters that arise from climate change in advance and developing necessary adaptation plans are crucial to mitigate their impacts. Drought progresses slowly but can profoundly impact entire ecosystems and human livelihoods. Many indices are introduced to analyse drought. This study aims to quantify the spatiotemporal response of groundwater systems to long-term meteorological and hydrological trends in the Seyhan Basin using the Groundwater Drought Index (GWI). It tests the hypothesis that groundwater drought exhibits a lagged but regionally distinct response to climatic drivers, especially in semiarid regions where topography, distance to the sea and anthropogenic withdrawals vary significantly. The years 1970–2016 were selected for analysing meteorological data and 1970–2015 for analysing hydrological data. Fifteen measurements from 24 meteorological observation stations (15 within the basin and 9 in neighbouring basins), 5 evaporation observation stations, 20 stream-gauging stations and 9 groundwater observation wells were utilised. The effects of analysed trends on GWI were examined, and climate change has been observed to impact drought parameters from a holistic perspective. Selecting an index appropriate to regional characteristics should be considered, and updating measurements is crucial for accurate predictions.