One of the main problems in reservoirs is sedimentation which reduces the operating life of dams if a proper plan and analysis method are not in place. The techniques to manage sediment in reservoirs include several sustainable management techniques that route sediment through or around the reservoir. One of the main economical methods in arid and semi-arid regions is pressurized flushing using moderate drawdown of the water level of the reservoir to evacuate sediment deposited behind dams. In the current study, the effect of a new structure called a dendritic bottomless extended (DBE) outlet structure at three angles of 30°, 45°, and 60° on pressurized flushing efficiency was investigated. Consequently, 45 experiments were designed for three discharge rates ($Q_o)$, three sediment levels ($H_s)$, four types of structure, and a no-structure condition (reference test). The results indicated that the DBE structure with a 30° angle between the branches, a sedimentary dimensionless index of $H_s/D_o=4.59$, and a flow dimensionless index of $Q_o/\sqrt{g{D_o}^5}=1.43$ (where $g$ is the acceleration of gravity and $D_o$ is the diameter of the bottom outlet) lead to 10-fold increase in the sediment flushing cone dimensions and sediment removal efficiency compared to the results of the reference test. Finally, according to a statistical analysis of the results, a dimensionless equation for calculating the sediment flushing cone dimensions was developed for the tested sediment characteristics.

水库的主要问题之一是沉积，如果没有适当的计划和分析方法，沉积会降低大坝的使用寿命。用于管理水库中泥沙的技术包括几种可持续的管理技术，它们可以使泥沙穿过水库或绕过水库。干旱和半干旱地区的主要经济方法之一是利用水库水位的适度下降进行加压冲洗，以排出沉积在大坝后方的沉积物。在当前的研究中，研究了一种新的结构，即在30°，45°和60°的三个角度下的树突状无底延伸（DBE）出口结构对加压冲洗效率的影响。因此，针对三种放电率设计了45个实验（${问}_{Ø}）$，三个沉积物水平（$H_s）$，四种类型的结构和无结构条件（参考测试）。结果表明，分枝之间的夹角为30°的DBE结构为$H_s/d_{Ø}=4.59$，并且流的无量纲索引为 ${问}_{Ø}/\sqrt{G{d_{Ø}}^5}=1.43$ （哪里 $G$ 是重力的加速度， $d_{Ø}$是底部出口的直径），与参考测试的结果相比，导致沉积物冲洗锥的尺寸和沉积物去除效率提高了10倍。最后，根据结果的统计分析，针对被测沉积物的特性，开发了用于计算沉积物冲洗锥尺寸的无量纲方程。