Abstract
<title>Abstract</title> <p> Constrained by topographic conditions, diversion channels of water intake pumping stations in sediment-laden rivers often adopt compact curved layouts, which induce disordered flow patterns and sediment deposition in the forebay and impair water conveyance efficiency and operational stability. Taking a forward-intake pumping station in China’s Jingdian Yellow River Irrigation District as the research object, this study selects the straight section length <italic>L</italic> , turning radius <italic>R</italic> and turning angle <italic>α</italic> of the diversion channel as core variables. Orthogonal tests coupled with computational fluid dynamics (CFD) simulations are conducted based on the Realizable <italic>k</italic> -ε turbulence model and Mixture multiphase flow model, and response surface methodology is applied to achieve multi-parameter collaborative optimization. Single-factor analysis indicates that increasing the turning angle continuously deteriorates forebay water-sediment distribution, the straight section length has an optimal value range, and enlarging the turning radius effectively mitigates sediment deposition. The influence weight of parameters ranks as straight section length, turning angle, turning radius. The optimized engineering thresholds are <italic>R</italic> ≥ 4.7 <italic>B</italic> ( <italic>B</italic> = channel water surface width), <italic>L</italic> ≥ 3.8 <italic>B</italic> and <italic>α</italic> ≤ 45°, under which the comprehensive water-sediment index rises by ≥ 5.24%. This study confirms that diversion channel geometric parameters are core factors regulating forebay water-sediment characteristics, and the proposed thresholds can provide technical support for the design and renovation of similar pumping stations in sediment-laden watersheds. </p>