Author(s): Jennifer G. Duan; Chunshui Yu
Linked Author(s): Jennifer G. Duan
Keywords: Hydrodynamic model; Flood routing; Rainfall-runoff; Watershed
Abstract: Anintegrated surface flow routing algorithm called SWE_KWA is developed in this paper. The algorithm is based the shallow water equations and the kinematic wave approximation. The system is discretized by the first-order Godunov-type finite volume method. The stability analysis shows that the friction source term increases exponentially as the flow depth becomes thin. This breaks the balance between the friction source term and the slope source term. A simplified implicit Euler scheme is derived from the kinematic wave approximation. This modification makes it possible to apply the shallow water equations to the whole domain, including both overland flow and channel flow. Test results show that the SWE_KWA is stable for the overland flow. The minimum allowable flow depth used in the tests is 10-10 m which is at least two orders of magnitude lower than the common rainfall excess rate (10-5 m – 10-8 m). The algorithm is only based the digital elevation model and does not require a channel network. This feature makes the SWE_KWA algorithm extremely valuable for solving the flow routing problems in ungauged watersheds.
Year: 2013