Author(s): E. Razafindrakoto; L. S. Martin; J. M. Hervouet
Linked Author(s):
Keywords: Navier-Stokes equations; Berre lagoon; 3D modelling; Water Quality; Hydrodynamics
Abstract: We present here the 3D modelling of the impact of fresh water release (from the Saint-Chamas hydraulic power plant) in the Berre lagoon, which potentially induces an ecosystem perturbation. This lagoon, situated in the South of France, has an area of 155 km2 and a volume of 980 millions m3. Measurement campaigns and in-situ monitoring enabled to set-up an exhaustive database on the hydrodynamics, the nutrients budget and the water quality of the lagoon and its tributaries. It was used to validate numerical simulations which show a very complex hydrodynamics depending on tide, density gradients and wind. Simulations of 5 years of real time are required, with time-steps of 1 minute which imply large Courant numbers and implicit schemes. The Telemac-3D computer program, developed at Electricite de France (EDF) Research & Development since 1987 [see Hervouet 2007], has been used for hydrodynamics. Massively parallel computations with domain decomposition have been necessary in this case [Hervouet 2009]. The final goal is to design scenarios for operating the Saint-Chamas power plant, in order to maintain a salinity level compatible with the existing ecosystem. 5-year computations of water quality in the lagoon will thus allow to support propositions of effective solutions for the Berre lagoon ecosystem restoration.
Year: 2009