Analysis on the Influence of Hydraulic Behavior in Stilling Basin towards the Scour Depth at the Downstream Spillway of Krueng Kluet Dam

Abstract

Changing the water flow leads to significant fluctuations in the water levels of the spillway, resulting in substantial energy changes as the water passes through and risking its stability. Consequently, spillway design must include the design of a stilling basin as an energy reducer to decrease the effects of scour. The primary objective of this research is to explain the influence of the hydraulic behavior in the stilling basin on the depth of scour downstream of the spillway structure. The study was conducted using the replica of the Krueng Kluet Dam spillway at the Dr. Masimin Hydrotechnic Physical Model Laboratory within the Faculty of Engineering, Syiah Kuala University, Indonesia. A dimensional analysis design methodology was deployed to examine the correlation between hydraulic parameters, including Froude number, hydraulic jump characteristics, energy dissipation efficiency, and scour depth. The research results show a direct relationship between discharge and both Froude number and hydraulic jump magnitude, resulting in corresponding scour depth. In addition, a higher discharge corresponds to a reduced energy dissipation efficiency, which contributes to increased scour depth. An anomaly observed in the efficiency-scour depth relationship is attributed to the generation of thin flow and its significant impact on the baffle block.