FORECASTING OF WATER-QUALITY IN LAKES - A PREDICTIVE USE OF A ONE-DIMENSIONAL MODEL - APPLICATION TO LAKE BOURGET (SAVOIE, FRANCE)

In order to assess the efficiency of eutrophication control programs, predictive models are necessary. We propose a methodology for implemen ting such a model, based on the coupling of a biogeochemical model of a lake and the use of long term time series of meteorological data. Th is methodology is applied to lake Bourget (Savoie, France). It allows to obtain both mean and standard deviation (first and second order mom ents) of the state variables of the model on a 1 y period. The sensiti vity of the model to the various forcing variables, as well as to the initial conditions is analyzed as well as the linear or non-linear beh avior of the model. Finally, the propagation of the uncertainties (sta ndard deviations) in time and space, for both water temperature and di ssolved oxygen are assessed.