Debris Flows, Boulders and Constrictions: A Simple Framework for Modeling Jamming, and Its Consequences on Outflow

Large boulders can jam in constrictions, both canyons and man-made structures (e.g., slit-dams). Boulder jamming occurs stochastically, partially governs the outflow rate of debris flow material. Explicit hydro-mechanical models boulder-laden flows are too computationally demanding to study this stochasticity. This presents a new framework implemented into numerical program. program encapsulates basic hydraulic equations criteria predicting boulder blockage at narrow sections, along with simple statistical way compute sizes numbers. The applies empirical estimates by experts average number deposit evaluate how equivalent multi-phase would interact constriction. model stochastically generates that obstruct constriction(s). outputs descriptions upstream level over time, as well downstream outlet discharge volume. is fast (5–30 s per run), allowing uncertainty propagation analyses interactions between flows, constrictions. Interaction low- high-risk be quickly evaluated for different scenarios. For propagation, we use possibility theory, which accommodates uncertainties relevant flows. gives practitioners much-needed generalized approach understanding long-term behavior through canyons, or designing engineered structures. Finally, apply field case – design proposed North American slit-dam thence elucidating requirements effective control. We found horizontal bars necessary dependably controlling from structure.