Trend analysis of lakes and sinkholes in the Konya Closed Basin, in Turkey

This study aims to investigate the trend of water-level changes in lakes (Lake Tuz and Lake Beyşehir) and sinkholes (Timraş and Kızören) in the Konya Closed Basin located in Turkey. Water-level changes in these lakes and sinkholes were investigated along with changes in meteorological parameters (precipitation, temperature, and evaporation) and groundwater trends that indicate the climate in the region. Several statistical tests can be used to determine the signifcance of hydrological trends over time. These tests are divided into two categories: parametric and nonparametric. In this study, the nonparametric Innovate Sen trend test, the Modifed Mann–Kendall trend test, and the parametric Linear trend test were used. According to the trend analysis, the water levels of Kızören and Timraş sinkholes decreased over time, while the water levels of lakes Tuz and Beyşehir increased. These results are supported by the trends in the meteorological data and groundwater level data of the stations determined with the Thiessen polygons and sub-basin boundaries.