Dynamic tracking of flow boundaries in rivers with respect to discharge

• Published in: Journal of hydraulic research 2002-01, Vol.40 (5), p.589-602
• Main Authors: Heniche, Mourad, Secretan, Yves, Boudreau, Paul, Leclerc, Michel
• Format: Article
• Language: English
• Subjects: Earth sciences; Earth, ocean, space; Exact sciences and technology; Freshwater; Hydrology; Hydrology. Hydrogeology
• ISSN: 0022-1686; 1814-2079
• DOI: 10.1080/00221680209499903

A new Eulerian approach is proposed to track the dynamic position of flow boundaries in rivers with respect to flow discharge or tides. Associated to a two dimensional (2D) transient horizontal hydrodynamic model, it allows to define the configuration of watercourses in a broad hydrological register varying from dry conditions to severe flooding. The finite element method is used to develop the numerical prediction tool. It is employed to estimate not only the classical flow variables such as water surface level and velocity field, but also the position of the shorelines. In this paper, the strategy followed for building this «drying-wetting» model consists in letting the water surface move freely, everywhere in the domain including the dry zones, allowing it to plunge under the ground. Two practical applications on rivers of Quebec (Canada) are presented. The first one deals with steady state situations on St. Marguerite River. The second one deals with the reconstitution of flood propagation on Chicoutimi River according to the extreme flooding events of July 96 in the Saguenay region.