Changes in regime characteristics of Sakarya River due to global climate change

As a result of global climate change, the flow and regime characteristics of streams change depending on the changes in climate elements, especially in precipitation. Each stream reflects the climate characteristics that are effective in its basin. The most important climate elements that determine the flow and regime characteristics of streams are temperature and precipitation. It is thought that the differences in climate elements that have accelerated due to anthropogenic factors in recent years are the result of global climate change. In this study, the changes in the regime characteristics of the Sakarya River due to the global climate change were investigated by using the measurement data of the stream observation stations and the climate data of the meteorological observation stations. Years involving research for the study are divided into three periods. These periods are 1965-1979, 1980-1994, 1995-2011. Accordingly, it has been determined that two of the meteorological stations have change in the precipitation regime. The meteorological stations that change in the precipitation regime are Sivrihisar and Bolu meteorological stations. The precipitation regime of Sivrihisar meterology station has changed in the period 1995-2011 and the precipitation regime of Bolu meteorological station in the period 1980-1994. There is no change in the regime of the stream. However, the annual average flow amounts for the periods indicate that there is a decrease in the flow amounts of the stream. There is no decrease in the flow amounts of the Meşecik stream observation station only. The period with the highest annual average flow in Meşecik is the last period, 1995-2011. Similar to the increases in global temperatures, the research area has experienced an increase in temperatures, especially in recent years. This increase is higher in the summer period.