Geomorphic dam-break flows. Part I: conceptual model

This paper presents a one-dimensional conceptual model for simulating geomorphic dam-break flows. The model is based on conservation laws drawn from continuum mixture theory that are integrated over the flow depth, assuming that the flow is composed of two transport layers. Closure equations were derived from the review and reanalysis of previous studies on granular flow, debris flow and sheet flow. The sediment transport is modelled assuming capacity regime. The closure equation coefficients are estimated based on a large set of experiments available in the literature. The validity of the model is discussed by computing the most relevant dimensionless parameters. The model is expected to simulate adequately the friction at the wave front and the sheet flow throughout the wave profile. Ultimately, although the problem incorporates complex phenomena, the model can be easily implemented by practising engineers for simulating one-dimensional geomorphic dam-break flows. The implementation and the verification of the adequacy of the model for simulating these flows are presented in a companion paper.