The aim of this project is to assess the complex relationships between climate, anthropogenic pressures and water resources in order to improve knowledge on water stress risks in the Vaud canton. During the past 30 years, there has been growing pressures on the canton's water resources. Successive dry years induced changes in flow regimes and high irrigation water needs. The canton also met one of the highest demographic growth of the country during the past decade. The last dry spells (e.g. summer 2003 and spring 2011) have shown that local authorities seem to be poorly prepared to face this issue due to a horizon still at a late date and the lack of concrete information on the causes and the possibility of water shortage episodes at the cantonal scale. The concern of M. Olivier Epars and of M. Marc-André Boiry on dry spells and more intense low water levels during summer expressed to the “Grand Conseil du Canton de Vaud” in 2010 and 2011 respectively is thus of high importance. Therefore, this project aims at developing an original integrated modeling method to provide answers to the following questions: what is the current water stress state in the different areas of the Vaud canton? In light of climatic and anthropogenic changes, how could water stress evolve in the canton by the 2050 horizon? Are expected water-use and hydro-climatic changes compatible? The project is divided into three main phases: (1) analysis of the hydrological regimes of the Vaud canton's hydrosystems; (2) setup of prospective water use and hydrological scenarios over the various catchments; (3) past and future analysis of areas most vulnerable to water shortage episodes.

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