Sedimentation in front of a dam is the main obstacle against reservoir sustainability. Due to the limited availability of suitable new dam sites, the ramifications of inefficient sediment management are associated with socio-economic concerns and environmental issues. Most of the existing sediment management techniques are unfavorable for arid and semi-arid regions due to their impacts on available water storage and power generation. Therefore, pressure flushing is an economical desilting method as it releases little water through the bottom outlet. However, one of the main disadvantages of pressurized flushing is limited sediment removal near the bottom outlet. In this paper, the impacts of a dendritic, bottomless, and extended (DBE) structure were investigated to develop the scour cone to a broader area. Several experiments were carried out with four different diameters (125, 160, 200, and 250 mm), four different lengths (30, 50, 80, and 110 cm), and three discharge rates (12.5, 15, and 18 L/s), to identify the dimensions of the extended structure with the most efficient operation. The results indicated that the DBE structure with a length dimensionless index of $L_{\mathit{DBE}}/D_o=10,$ a diameter dimensionless index of $D_{\mathit{DBE}}/D_o=1.14$, and an outflow discharge dimensionless index of ${\mathit{Fr}}_o=1.82$, yielded a 36.55-fold increase in the sediment flushing cone dimensions and sediment removal efficiency compared to a reference test. Finally, a dimensionless equation is presented for calculating the sediment flushing cone dimensions, according to a statistical analysis of the results. Two diagrams are provided to illustrate the interrelationship between the distance limits of scour, length, and diameter of the structure and outlet discharges.

大坝前的沉积物是水库可持续性的主要障碍。由于合适的新坝址的可用性有限，低效的沉积物管理的后果与社会经济问题和环境问题有关。大多数现有的沉积物管理技术不利于干旱和半干旱地区，因为它们会影响可用的水储存和发电。因此，压力冲洗是一种经济的清淤方法，因为它通过底部出口释放的水很少。然而，加压冲洗的主要缺点之一是底部出口附近的沉积物去除有限。在本文中，研究了树枝状、无底和扩展 (DBE) 结构的影响，以将冲刷锥扩展到更广泛的区域。用四种不同的直径（125、160、200 和 250 毫米）、四种不同的长度（30、50、80 和 110 厘米）和三种排放速率（12.5、15 和 18 L/s）进行了几次实验)，以识别具有最有效操作的扩展结构的维度。结果表明，具有长度无量纲索引的 DBE 结构为${\mathrm{大号}}_{\mathit{DBE}}/D_{○}=10,$直径无量纲指数$D_{\mathit{DBE}}/D_{○}=1.14$, 和流出流量无量纲指数${\mathit{神父}}_{○}=1.82$，与参考测试相比，沉积物冲洗锥尺寸和沉积物去除效率增加了 36.55 倍。最后，根据对结果的统计分析，提出了计算冲沙锥尺寸的无量纲方程。提供了两个图表来说明冲刷距离限制、结构长度和直径与出口排放之间的相互关系。