A platform to harmonize the regional hydrodynamic models in the southwest of France

Arnaud Wuilleumier (1) , Marc Saltel (1) , Olivier Douez (1) , Olivier Cabaret (1) , Léna Abasq (2) , Nicolas Pedron (1)

1 BRGM - Bureau de Recherches Géologiques et Minières (BRGM)
2 GEOSCIENCES - Centre de Géosciences

To support the authorities in water resource management, different hydrodynamic models have been developed in south-western France (the new Large Region: Aquitaine - Limousin - Poitou-Charentes) for nearly twenty years. These models also contribute to understand the functioning of multilayered aquifers on this territory. Four developed models coexist and cover a total area of 82,570 km² (Jurassic and Cretaceous models in Poitou-Charentes, the North Aquitaine Model and the South Aquitaine Model). They cover 87% of the sedimentary formations of the new Large Region. In addition of these regional models, others models with refined geometry or mesh have been developed on a part of the same territory in order to respond to local and specific problems. All these models, developed independently from each other, will be integrated in a common platform in order to harmonize their functioning with the experience gained during the development and the use of each of them. Thus, the use of a geological modeler upstream to create geometrical models allows some flexibility in order to regularly integrate the latest geological data (used for the North Aquitaine Model). Moreover, the use of climate spatialized data (SAFRAN data from Météo-France) coupled with the use of a specific recharge module allows to homogenize and calculate in the same way the groundwater recharge in the different models (used for the Jurassic model). Including the restitution of surface runoff and rivers flow in modeling allows as well to properly constrain the distribution of effective precipitation between infiltration and runoff. Finally, a database of water withdrawals is built to handle and treat in the same way data from different origins with variable time step and specific issues to be considered in each model (water withdrawals in groundwater and/or surface for various uses as water supply, industry, irrigation, dam releases, sewage discharges, etc.). All of these works aim to consolidate regional hydrodynamic models and to allow the update and faster adaptation of these models.

Mots clés: Aquitaine Basin; Hydrodynamic Model; geological modeler; groundwater recharge; Harmonization

Domaines: Hydrologie

Arnaud Wuilleumier, Marc Saltel, Olivier Douez, Olivier Cabaret, Léna Abasq, et al.. A platform to harmonize the regional hydrodynamic models in the southwest of France. 43rd IAH Congress, Sep 2016, Montpellier, France. . ⟨hal-01329510⟩