Author(s): Schippa Leonardo; Pavan Sara
Linked Author(s): Leonardo Schippa
Keywords: Numerical model; Mobile bed; Dam erosion; Breach development; Overtopping failure
Abstract: A numerical model, suitable for alluvial rivers morphology evolution is presented. It is based on an original conservative formulation of one-dimensional shallow water equations including a new treatment of source terms, which improves numerical stability. Sediment mass balance is treated with the Exner equation. The simple MacCormack explicit finite- difference numerical scheme is used and a semi-coupled procedure has been adopted. A TVD algorithm is also implemented to handle with rapidly varying flow conditions. In recent works, various mechanisms of bed evolution in different water regime conditions have been considered, in order to verify model response in case of erosion, deposition, bed morphology evolution and homogenous embankment overtopping. In this paper, dam failure consequent to breach formation is investigated. Numerical simulations are based on a set of laboratory experiments. The model demonstrates to correctly interpret both reservoir depletion and breach development. Breach enlargement process is addressed adopting a simplified erosion scheme, based on sediment mass conservation. Numerical results are compared with experimental data showing satisfactory agreement, although some uncertainties in the choice of transport formula are encountered.
Year: 2005