Approximate Models for Flood Routing

Abstract

For rapid calculation of the downstream effects of the propagation of floods due to the collapse of a dam or intense rainfall, two approximate flood routing models are presented in this paper. A nonlinear technique for flood routing is developed that respects the physics of floods in waterways. The models are developed based on the assumption that the change in flow rate relative to the initial uniform flow rate is moderate. A nonlinear kinematic model and a nonlinear convection-diffusion model are extracted from a normalized form of the St. Venant equations, and applied to the analysis of translatory waves usually encountered in rivers and water-courses due to the propagation of floods. The qualitative analyses presented shows that the approximate flood routing models could be used instead of the complete hydrodynamic equations when the perturbation in the initial normal flow condition is moderate.