Investigation on Changes of the Sakarya River Characteristics

After construction of dams, the hydrologic and hydraulic characteristics of rivers change drastically. Many researchers investigated these changes, affecting services and structures. The changes of river flow and sediment transport cause riverbed scour at downstream section. In this study, changes in the Lower Sakarya River are investigated after construction of Gokcekaya Dam in the Middle Sakarya Basin. Furthermore, gravels have been withdrawing from the Lower Sakarya River especially within 5 decades in order to meet construction materials for the surrounding large cities. Changes of expected probable floods are determined by using annual maximum discharges at both same stations. It is noticed that as the flood peak discharge decrease, the river flow regime is regulated. Sediment rating curves are determined and compared by using measured suspended load for before and after the dam. It is observed that the sediment transport was decreased at a rate 40–65 % after the Gokcekaya Dam.