Modeling of dam break wave propagation in a partially ice-covered channel Musandji Fuamba * , Najib Bouaanani, Claude Marche Department of Civil, Geological and Mining Engineering, E ´ cole Polytechnique de Montre ´al, Montre ´al, QC, Canada H3C 3A7 Received 22 January 2007; received in revised form 1 June 2007; accepted 4 June 2007 Available online 3 July 2007 Abstract During the last four decades, several numerical formulations and specialized software have been developed in response to studies about dam break (DB) wave propagation and its hydraulic and environmental impacts on downstream hydraulic structures and valleys. These methods cannot, however, be used to predict wave propagation within partially covered channels or reservoirs located upstream of hydraulic structures. In fact, such problems require the modelling of the complex transition from a free surface flow into a pressurized one. Because rivers or channels partially covered with ice sheets are typical examples commonly met in winter in northern climates, it is vitally important to assess ice-cover effects on the DB wave propagation and develop appropriate tools to predict resulting hydrodynamic loads on hydraulic structures downstream. This paper proposes an original numerical formulation to model wave propagation and hydrodynamic pressure in partially covered channels. The proposed formulation uses one-dimensional St. Venant equations to simulate open-water flow and water hammer equations to simulate pressure flow within the partially covered channel. To illustrate the use of the hydrodynamic pressures obtained, a case study is presented where a channel cover and a dam located downstream are modelled using finite elements to investigate their dynamic structural response. Ó 2007 Elsevier Ltd. All rights reserved. Keywords: Free surface flow; Pressurized flow; Dam break wave; Flood wave; Wave propagation; Dynamic load; Ice-cover; Finite differences; Finite elements 1. Introduction Dam break (DB) waves are translatory waves that may result from the failure of dams, dykes or other control structures. The resulting extreme water level changes gener- ated by these large water masses could create critical flood and dam break waves with high amplitudes carrying signif- icant energy. The nature of dam break waves depends on the dam type and reservoir capacity. Water waves induced by earth (or rock) fill structural failures are generally long waves, whereas those generated by concrete gravity dam failures are short ones; a large reservoir capacity could gen- erate long waves and short waves could be created by a reduced capacity. DB waves result in significant hydraulic and environmental impacts, critical for people, property and buildings located along a river, a channel, and an impounded reservoir or downstream of a dam. Special care should be taken with dams built in cascade because of the ‘Domino effect’ in which the effects of the failure of one dam at the upstream of the cascade are amplified as long as the waves propagate, thus seriously compromising the structural stability of the dams downstream. In regions with severe winters, water surface between two consecutive dams can be totally or partially covered with ice. Recent experimental and numerical studies have investigated the influence of ice-covers on the dynamic response of dam–reservoir systems to forced-vibrations or earthquake excitation [2,3]. Although a stable ice-cover in 0309-1708/$ - see front matter Ó 2007 Elsevier Ltd. All rights reserved. doi:10.1016/j.advwatres.2007.06.005 * Corresponding author. Tel.: +1 514 340 4711x4813; fax: +1 514 340 4191. E-mail address: musandji.fuamba@polymtl.ca (M. Fuamba). www.elsevier.com/locate/advwatres Advances in Water Resources 30 (2007) 2499–2510