Optimizing stilling pool design for climate-resilient hydrology: insights on water level difference and energy dissipation

In canal navigation systems, stilling pools are vital for reducing velocity and ensuring waterway operations. This study focuses on the impact of upstream and downstream water level differences on the energy dissipation effect of stilling pools. A three-dimensional numerical model was established to analyze hydraulic under various water level drops and pool size conditions. The results show that under water level drops, the length of the pool and the angle of the tail sill have similar influence patterns on the energy dissipation, while the influence of the pool depth presents a unique pattern: as the water level drop increases, the effect of the pool length on enhancing the energy dissipation effect weakens, with the optimal length being 50 m and the optimal depth being 0.5 m; the influence of the tail sill angle varies with the water level drop – at a 2.2-m drop, a 60° tail sill angle achieves the best effect, and at larger drops, a 30° tail sill angle is more suitable. The research results can provide a reference for the optimization of the stilling pool design, to enhance its energy dissipation stability under different hydrological conditions and improve the scientificity and rationality of water conservancy engineering design.