Exemple de prévision et de simulation opérationnelle des débits d'étiage pour les besoins d'EDF

An example of forecasting and operating simulation of low water flows

EDF, Division Technique Générale

Abstract

In low water level situations, it is hard to manage all water resource requirements, EDF, in particular, uses water for energy purposes both for heat production means which require a minimum flow for their cooling and for dilution of their effluents, and for its hydraulic production means whose reserves allow expensive fuels to be saved during peak demand periods. Use of water resources must also take into account the additional demand corresponding to other needs such as agricultural, industrial, tourist or related to water quality. In such conditions, to ensure optimum management of a dam, knowledge and short-term forecasting of natural flows enable water to be released in sufficient quantity to satisfy downstream needs while ensuring maximum water savings to cope with future needs. Moreover, simulation of long-term hydrological scenarios makes it possible to forecast the occurrence of events identified as critical, such as the overshooting of certain flow thresholds or their persistence in time, in order to anticipate the consequences of these events on operation of the installed production base, EDF is therefore gradually acquiring the tools needed for knowledge and forecasting of water resources in low water level situations: pluviometrie and hydrometric stations, conceptual and statistical hydrological forecast models, data servers, low water level indicator statistical analysis models, water resource indicators. This approach is illustrated by the current achievements and developments in the Vienne and Loire basins.