EVALUATION OF SAKARYA RIVER STREAMFLOW AND SEDIMENT TRANSPORT WITH RAINFALL USING TREND ANALYSIS

Abstract

Water has always been the focus of living things and civilizations have been established mainly in areas close to water. However, to meet the growing need for water, measures were taken such as transporting water from areas with abundant water to areas with water scarcity. The most effective method is to examine the behavior of water in the past and to estimate its future behavior. On the other hand, excess water, which is transported at the time of a flood carries a lot of sediment and transported sediment results in significant losses during floods. Thus, it is also important to know the change of sediment transport with water over time. In addition, possible rainfall which may come in future needs to be estimated by looking also at the history of rainfall that comes with rain. Excessive rains cause flooding and sediment transported by the flood causes erosion. Therefore, in this study, the relationship among Sakarya River streamflow and sediment transported with rainfall is analyzed by applying trend analysis. The Mann-Kendall test and Spearman Rho test were used in the study. The Mann-Kendall Rank Correlation test was used to determine the trend's starting year. An analysis of test results revealed a downward trend in The Spearman's Rho test and Mann-Kendall test. In Mann-Kendall Order Correlation test conducted to obtain the starting year of the trend, a direct relationship was found among the starting years of the tend in each parameter. Thus, the trends declining also for each parameters show a direct relationship among the streamflow, sediment and rainfall. In addition, downward trends in test statistics of Sakarya River also indicate that water will decrease in next years. Thus, to leave a healthy and adequate amount of water to the next generations, Turkey should preserve and rationally use its sources.