The Impact of Spur Dike and Submerged Vanes on Sediment Control at Lateral Intake

Sediment control at lateral intakes is known as a very common problem and the most complicated issue for river engineers. Since a larger portion of the near-bed flow is diverted, the intake will receive a relatively large amount of bed load materials. Thus, appropriate and reliable methods are needed to minimize the amount of diverted sediment materials into the intake of a river. In this research, a laboratory study was carried out to explore a possible solution method using two types of river structures simultaneously including a set of submerged vanes and a single spur dike. Submerged vane by setting a tip vortex and a helical flow in downstream, can reduce the movement of bed sediment flow into a diversion. In this study, the optimum dimensions, number and array of vanes were selected as determined by the regular design method. For guiding flow into the diversion and increasing the vane performance, a single spur dike in opposite side of intake was utilized. The main goal of the experiment was to evaluate the effect of spur dike length, the location of intake, and the angle of attack on reducing the movement of bed sediment into the diversion. Experimental tests included three lengths of spur dike: 15, 20, 25 cm with 0, 40, and 80 cm distance from the intake with angles of 45^o, 90^o and 135^o, respectively. The results showed that the effective performance of the vanes increased and Concequently eliminated the bed sediment ingestion into diversion at qr=0.3 once they used with a single spur dike at opposite side of the intake. An average reduction of 40% in sediment ingestion into diversion was observed a spur dike located at a distance of twice intake width from the centre line as. Furthermore, the results indicated that among the three angles of spur dike investigated, the sediment movement into the intake was minimized by using an angle of 90⁰.