FLOOD ROUTING IN STEEP STREAMS

Abstract

Flood routing techniques employing numerical models, especially those based on implicit finite difference schemes, have now been reasonably well accepted in practice. However, when they are applied to steep natural streams with slopes greater than 0.0005, the problem of numerical instability often arises, resulting in break-downs of numerical models. Major factors affecting numerical stability include streem slope, cross-sectional variability, tributary confluence, boundary conditions and initial conditions. The present article reviews and summarizes some of the research results obtained by the author in recent years. Stability criteria under various influencing parameters are given, and applications to field cases in Taiwan are also illustrated in this article.