Water quality trend analysis in Eymir Lake, Ankara

In this study, trends in selected water quality parameters in Eymir Lake over a period of 10 years are analyzed using the Mann–Kendall test. Analyzed water quality parameters are dissolved oxygen (DO), total phosphorus (TP), total suspended solids (TSS), and secchi depth (SD). In addition, trends in the yearly averages of precipitation, lake volume, and ambient temperature are examined. According to Mann–Kendall test results, precipitation, volume and ambient temperature values exhibit decreasing trends in 1998–2008. DO and TSS exhibit increasing trends while TP and SD have decreasing trends in Eymir Lake. The change in the volume of the lake has a significant impact on the trends of DO, TSS, and SD. These results indicate that, besides eutrophic conditions, water balance and drought conditions significantly impact the water quality of Eymir Lake.