Dual-method assessment of runout distance for channel-type waste dump failures based on energy conservation screening model and depth-integrated continuum simulation

The direct comparisons tailored to channel-type waste dumps are scarce, which leaves engineers without evidence-based guidance on when a screening estimate is sufficient and when a higher-fidelity simulation is needed. This study assesses the runout distance of a channel-type waste dump in the Panxi region (SW China) under an extreme-rainfall scenario by combining an Energy Conservation Method (ECM) screening model with a Depth-Integrated Continuum Method (DICM) simulation. By comparing predicted runout distances and examining the influence of channel geometry on flow routing, we propose a tiered, cross-model triangulation workflow for risk assessment of similar dumps. For a plausible 5,280 m³ local failure, ECM predicts a screening runout distance of S = 378.72 m. The DICM simulation re-solves a 350 s dynamic process with distinct initiation, propagation and deposition phases, yielding a peak velocity of 8.54 m/s and a final runout of S = 354 m. Relative to the downstream residential receptor at LR = 430 m, both methods indicate no direct inundation but a near-miss, with impact margins (LR − S) of 51 m (ECM) and 76 m (DICM). The two runout estimates differ by