Dam-break flow simulation: some results for one-dimensional models of real cases P. Garcia-Navarro * , A. Fras, I. Villanueva Department of Fluid Mechanics C.P.S., University of Zaragoza, 50015 Zaragoza, Spain Received 20 July 1998; accepted 12 January 1999 Abstract In many countries, the determination of the parameters of the wave, likely to be produced after the failure of a dam, is required by law, and systematic studies are mandatory. There is a necessity to develop adequate numerical solvers which are able to reproduce situations originated from the irregularities of a non-prismatic bed and to model the complete equations that progress despite the irregular character of the data. Many hydraulic situations can be described by means of a one-dimensional (1D) model, either because a more detailed resolution is unnecessary or because the flow is markedly 1D. Many techniques have been developed recently for systems of conservation laws in 1D (in the context of gas dynamics). Some years after their adoption for solving problems in gas dynamics, upwind and total variation diminishing (TVD) numerical schemes have been successfully used for the solution of the shallow water equations, with similar advantages. Their use is nevertheless only gradually gaining acceptance in this sector. The performance of some of these techniques for practical applications in river flow is reported in this work.  1999 Elsevier Science B.V. All rights reserved. Keywords: Flood routing; Explicit TVD methods; Unsteady shallow water flows; Dam break flow 1. Introduction Many problems of river management and civil protection consist of evaluation of the maximum water levels and discharges that may be attained at particular locations during the development of an exceptional meteorological event. There is another category of events of catastrophic nature whose effects also fall into the civil protection area. It is the prevision of the scenario subsequent to the almost instantaneous release of a great volume of liquid. The situation is that of the breaking of a man made dam. In many countries, the determination of the para- meters of the wave, likely to be produced after the failure of a dam, is required by law (Molinaro,1991; Betamio de Almeida and Bento Franco, 1993), and systematic studies are mandatory. There are works based on scaled physical models of natural valleys, but they represent expensive efforts that are not devoid of difficulties. Hence, there is a necessity to develop adequate numerical models which are able to reproduce the situations that originate from the irre- gularities of a non-prismatic bed. It is also necessary to trace their applicability considering the difficulty of developing a model capable of producing solutions of the complete equations despite the irregular character of the river bed. For many practical applications, it is accepted that the unsteady flow of water in a one-dimensional (1D) approach is governed by the shallow water or St. Venant equations. These represent the conservation Journal of Hydrology 216 (1999) 227–247 0022-1694/99/$ - see front matter  1999 Elsevier Science B.V. All rights reserved. PII: S0022-1694(99)00007-4 * Corresponding author. Fax: +34-976761882. E-mail address: pigar@posta.unizar.es (P. Garcia-Navarro)