This study is carried out with the purpose of developing the effective methods to release sediment out of dam reservoirs. Piles and submerged Vanes are employed in front of bottom outlet to enhance vortex flow and their effects were tested. The piles are embedded in different distances from each other and bottom outlet. The results indicated that Piles performance was improved with minimum distance and the rate of sediments evacuated in the water levels of ۵۰, ۳۰ and ۱۵ cm, were increased about ۷۶, ۱۱۳ and ۱۴۱%, respectively. The submerged Vanes were also fixed in different distances from the outlet and three different angles with respect to flow direction. The results showed that when the Vane distance from outlet was minimum and the angle of the Vane was less, the intensity of vortex flow was increased. As a result, the amounts of sediment evacuated in the water levels of ۵۰, ۳۰ and ۱۵ cm, were increased about ۱۶۳.۵, ۳۳۷.۱ and ۴۸۱%, respectively. In general, the results indicated that in releasing sediments from reservoirs the submerged Vanes have better performance than piles.This study is carried out with the purpose of developing the effective methods to release sediment out of dam reservoirs. Piles and submerged Vanes are employed in front of bottom outlet to enhance vortex flow and their effects were tested. The piles are embedded in different distances from each other and bottom outlet. The results indicated that Piles performance was improved with minimum distance and the rate of sediments evacuated in the water levels of ۵۰, ۳۰ and ۱۵ cm, were increased about ۷۶, ۱۱۳ and ۱۴۱%, respectively. The submerged Vanes were also fixed in different distances from the outlet and three different angles with respect to flow direction. The results showed that when the Vane distance from outlet was minimum and the angle of the Vane was less, the intensity of vortex flow was increased. As a result, the amounts of sediment evacuated in the water levels of ۵۰, ۳۰ and ۱۵ cm, were increased about ۱۶۳.۵, ۳۳۷.۱ and ۴۸۱%, respectively. In general, the results indicated that in releasing sediments from reservoirs the submerged Vanes have better performance than piles.This study is carried out with the purpose of developing the effective methods to release sediment out of dam reservoirs. Piles and submerged Vanes are employed in front of bottom outlet to enhance vortex flow and their effects were tested. The piles are embedded in different distances from each other and bottom outlet. The results indicated that Piles performance was improved with minimum distance and the rate of sediments evacuated in the water levels of ۵۰, ۳۰ and ۱۵ cm, were increased about ۷۶, ۱۱۳ and ۱۴۱%, respectively. The submerged Vanes were also fixed in different distances from the outlet and three different angles with respect to flow direction. The results showed that when the Vane distance from outlet was minimum and the angle of the Vane was less, the intensity of vortex flow was increased. As a result, the amounts of sediment evacuated in the water levels of ۵۰, ۳۰ and ۱۵ cm, were increased about ۱۶۳.۵, ۳۳۷.۱ and ۴۸۱%, respectively. In general, the results indicated that in releasing sediments from reservoirs the submerged Vanes have better performance than piles.This study is carried out with the purpose of developing the effective methods to release sediment out of dam reservoirs. Piles and submerged Vanes are employed in front of bottom outlet to enhance vortex flow and their effects were tested. The piles are embedded in different distances from each other and bottom outlet. The results indicated that Piles performance was improved with minimum distance and the rate of sediments evacuated in the water levels of ۵۰, ۳۰ and ۱۵ cm, were increased about ۷۶, ۱۱۳ and ۱۴۱%, respectively. The submerged Vanes were also fixed in different distances from the outlet and three different angles with respect to flow direction. The results showed that when the Vane distance from outlet was minimum and the angle of the Vane was less, the intensity of vortex flow was increased. As a result, the amounts of sediment evacuated in the water levels of ۵۰, ۳۰ and ۱۵ cm, were increased about ۱۶۳.۵, ۳۳۷.۱ and ۴۸۱%, respectively. In general, the results indicated that in releasing sediments from reservoirs the submerged Vanes have better performance than piles.