Abstract: Numerical simulation based on k-ε double-equation turbulent model is employed to research the pressure characteristics at the bottom of natural step-pool system in mountainous rivers and the structural safety of riverbed under different flow rates. Four numerical experiments show that pressure distribution at the bottom of step-pool is relatively uniform in the shape of closed curves, which ensures that energy disperses into the mainstream around quickly. Moreover, step-pool system has self-adaptive ability in adjusting the morphology and water depth in the pool area. A water cushion is formed to ensure that the differential pressure distribution becomes stable, thereby preventing the riverbed from being destroyed by direct increase in energy and pressure concentration, which is beneficial to the riverbed’s safety and stability.

Key words: step-pool, bottom of the pool, numerical simulation, pressure distribution, riverbed stability