Evaluating Drought Patterns in Gediz Basin with Advanced Statistical Techniques and Indices

Drought, defined as a reduction in water resources over a period of time, has become one of the most costly natural disasters in recent years due to industrialisation, rapid population growth and climate change. The aim of this study is to gain a better understanding of drought trends in the Gediz Basin, Turkey, and to provide information to relevant institutions and organisations to mitigate the effects of drought. To achieve this goal, drought analyses were conducted using seven different drought indices and five different statistical methods based on data from six meteorological stations in the Gediz Basin. The results of the drought indices indicated the occurrence of both dry and wet periods at different times. Significant correlations were observed between the reconnaissance drought index (RDI) and the percent of normal index (PNI). Additionally, the standardized precipitation index (SPI) also captured drought conditions during the same period as the RDI and PNI. However, the correlation between SPI and the other two indices was lower, primarily due to the SPI detecting lower levels of drought severity. Trend analyses showed a decrease in precipitation values, especially during the summer months, and an increasing trend in temperature values. The study recommends using the RDI index to assess meteorological drought, while the Pinna Combinative index can be used to assess hydrological drought in the basin. These findings are expected to provide valuable insights for the development of drought management plans and necessary measures in the Gediz Basin.