Evaluation sediment dynamism in sedimentation pool: Example of Çankırı basin – Tımarlı location

Our country consists of semi-arid climates, steep slopes, sloping and mountainous regions. While landslides occur frequently with the massive movement of the soil as a result of sudden floods from steep slopes and stream sides, erosions may occur throughout the basin as a result of heavy rains. As a result of these, a significant amount of sediment is transported in the river beds. The sediments carried by the swab or suspended movement with the flow in the river beds seriously reduce the flow velocity in the reservoirs of structures such as dams. While a significant part of it is precipitating, it may be necessary to establish additional sedimentation ponds in order to ensure sufficient sedimentation of sediment in regulator-like structures. For this reason, the water to be transmitted through communication channels for irrigation purposes to agricultural areas should be purified from relatively coarse sediments. In order to, prevent precipitation risks that may occur along the transmission line and to carry relatively clear water, in irrigation projects where water supply will be provided with the help of a regulator. Sedimentation ponds can be designed at the beginning or in certain parts of the main canal. In addition, thanks to the sedimentation pools, the clogging of critical structures such as siphons and culverts manufactured for road crossings or stream crossings to be installed along the transmission line will be prevented easily. Within the scope of the thesis, information about the calculation of the length of the first settling pool with a length of 40 m is given. In the HEC-RAS program, a model of the structure was created by defining the places where the sections changed to represent the sedimentation pool. The settling distance can be calculated by considering the results obtained in the HEC-RAS program and the minimum particle diameter desired to be deposited. Many equations are suggested in the literature to determine the settling distance. The equation most frequently used by DSI is the one developed by Sümer in 1977 due to its practicality. As a result of the calculations and according to minimum the grain diameter desired to be precipitated, it was concluded that the size of the sedimentation pool determined by DSI is exactly the same and appropriate with the size of the field.