2014 Volume 62 Pages 131-140
Flash flooding due to a dam failure brings about catastrophic consequences involving destruction of buildings and loss of human lives. Numerical models based on the 1-D shallow water equations serve as essential tools for effective flood risk analysis. However, conventional models have difficulties in consistently handling rapidly varying transcritical flows involving steep slopes, general cross-sections, wet and dry interfaces, and junctions. This study proposes an efficient and easily implementable numerical model for flash flooding, referred to as CDFVM, utilizing a simple finite volume algorithm with local Froude number as a weight. The CDFVM has a model parameter to be tuned, whose optimal value is determined so that wet and dry interfaces in idealized dam break problems are accurately captured. The CDFVM is successfully applied to numerical simulation of a dam break problem with wet and dry interfaces in a multiply connected (looped) open channel network.