Trend analyses for monthly and annual precipitation data in buyuk menderes basin

Basin management can be defined as the planning approach in which water resources are handled at basin scale considering the parameters such as rainfall, flow, temperature and evaporation. The concept of integrated basin management is an important approach in planning and management of water resources in the world. It is based on the implementation of planning, organization and control mechanism that responds the views, expectations and objectives of all segments concerned. Beyond the quantitative - qualitative distribution of water in the basin, the effective use of water is important. Effective use of water is also possible with efficient evaluation of existing water resources, in addition to control consumption of water. In this context, current meteorological data in the basin must be evaluated and analyzed correctly and also must be calibrated with flow observations. In many studies on water resource planning, a trend can be observed in the recorded data due to the effects of climate change or changes in precipitation conditions. Determining the start date and the characteristics of trend has great importance for basin management decisions. In this study, monthly and annual precipitation data obtained from 40 different precipitation observation stations which belong to The General Directorate of State Hydraulic Works and Turkish State Meteorological Service in Büyük Menderes Basin were analyzed using trend analysis. Significance of trend values were analyzed by using Basic Linear Regression and Mann-Kendall tests; it was determined that total monthly and annual precipitation did not tend to increase or decrease on basin.