Prospective approach for assessing change in water resources management for large river basins in France
Résumé
Water management planning is influenced by many natural and human factors that interact at basin scale. A multidisciplinary approach is therefore required to both understand and well represent the main characteristics of the water system before analysing its sustainability under global change and suggesting efficient adaptation measures. The complexity of the interactions and thus the challenge in modelling increase with the size of the river basin. This talk presents the main results of the research project R2D2-2050 “Risk, water Resources and sustainable Development within the Durance river basin in 2050” (Sauquet et al., 2014). The Durance River, one of the major rivers located in the Southern part of the French Alps, supplies water for competing human uses (irrigation, hydropower, drinking water, industries and more recently tourism and ecological services) within and out of the drainage area through an extended open channel network. The project R2D2-2050 aimed to assess whether the current water management - especially operating rules for the three main reservoirs - would need changing under future conditions taking into account evolutions in both climate and socio-economy.A multi-model approach was carried out to simulate regional climate, water resources, irrigation needs, water supply for domestic purposes, water transfers and reservoir operations. A model of water management similar to the operational tool used by the French hydropower producer EDF was also developed to simulate water released from the reservoirs on present-day conditions under constraints imposed by ecological flows and water levels in summer for recreational purposes. Four territorial socio-economic scenarios have been also elaborated with the help of stake holders to project water needs in the 2050s for the area supplied with water from the Durance River basin.