Modélisation de la qualité des eaux des lacs profonds : modèle thermique et biogéochimique du lac du Bourget

Deep lakes water quality modelling: Thermal and biogeochemical model of Lake Bourget (France)

CERGRENE, Ecole nationale des Ponts et Chaussées, Paris

Abstract

In 1981, important works including diversion of the main sewers coming into lake Bourget (one of the largest french alpine lakes) have been implemented. In order to quantify the restoration of the water quality standards, a project including a detailed water quality survey (1988-89) and the thermal and biogeochemical modelling of the lake is undertaken. The model (Temperature, Phosphorus and Oxygen) is one-dimensional vertical. It is based on the advection-diffusion equation. Results of the thermal model agree with the observed seasonal and long-term evolution of temperature in lake Bourget. The results of the biogeochemical sub-model for the calibration phase are presented.