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Determining the change in the amount of evaporation is important for water resources management, design of water structures and preparing water action plans. In this study, trends of total monthly pan evaporation data for Gaziantep, Şanlıurfa and Mardin stations located as Southeastern Anatolia Region, which is important agricultural area of Turkey, are carried out using non-parametric Mann-Kendall (MK) and Innovative Trend Analysis (ITA) methods. The linear trend slope is determined with Sen's slope method. As a result of the study, the significant increasing trend is found with MK test in May and September at 95% confidence level and in October at 90% confidence level. The highest increase in this station according to the linear trend slope values is calculated 0.98%/year. As a result of analysis with ITA method, there is a trend occurrence in low, medium, and high values. It is concluded that ITA method can be used as an alternative method to monotonic trend analysis methods, since its ease of calculation and its ability to give results graphically. [ABSTRACT FROM AUTHOR]

In this study, it was aimed to investigate long-term trends of annual precpitation data recorded in sixteen stations operated by DMI (Turkish State Meteorological Service) and DSI (State Hydraulics Works) in Büyük Menderes Basin (Turkey) using Mann-Kendall test with TFPW (Trend-Free Prewhitening) procedure that eliminates the serial correlation for time series containing serial correlation. The slopes of trends were determinded by Sen's Slope Estimator. Homogeneity of trends among stations was tested using Van Belle and Hughes test. The results showed that total annual rainfall increased at only two stations, while decreased at other stations. However, the trend at only one station is statistically significant at 5% level. Temporal patterns of DSI-stations were found to be consistent with those of DMI-stations. Decreasing trends among the stations was found to be homogeneous. It is expected that demand on fresh water resources will increase due to decreasing rainfall as a consequence of climate change, together with domestic, industrial and agricultural water use. To cope with the expected water scarcity in the basin, reuse of treated wastewaters, especially in agriculture, may provide an important opportunity. Hence, this may alleviate the competition among water users, and fresh water resources can be allocated to domestic and industrial use. [ABSTRACT FROM AUTHOR]