The effect of climate change on stream basin hydrometeorological variables: The example of Dim Stream (Turkey)

Climate change is causing serious problems in various economic sectors in particular involving water management. For this reason, it is extremely important to conduct research to identify climate change trends and better understand them. This study was carried out in the Dim Stream basin in the Western Mediterranean region (Turkey), which is particularly vulnerable to climate change. The study used flow data from two flow observation stations (FOS) and meteorological records such as wind speed, average flow, precipitation, temperature, evaporation, radiation, and relative humidity for 1984-2017. These data showed the changes between flow and hydrometeorological variables using linear regression analysis, coefficient of variation, t-test and correlation analysis. It has been determined that there has been a rapid decrease in the average flow of the FOS number 09-006 since 1995 and the average flow of the FOS number 09-013 since 1999. Also, it was demonstrated that the average relative humidity (RH_ave), average temperature (T_ave), average precipitation (Pave), total precipitation (Pt) and maximum precipitation (P_max) meteorological variables were most affected by climate change in the basin. Furthermore, it was found that the most changes were Qy_ave (67.60%), T_min (48.23%), P_max (36.43%), P_ave (33.91%), P_t (33.90%), and RH_ave (2.63%) in FOS numbered 09-013. Moreover, it was concluded that climate change variability had developed trends towards a rapid decrease in the flow values at the flow observation stations in Dim Stream. These results show that plans and measures for the efficient and sustainable management of water resources in this region must be implemented immediately.