The Rhône River, France: applying integrative sciences to sustainable management

The Rhône River is one of the main European alpine rivers (watershed: 98 500 km2; length: 812 km total, 560 km in France; mean annual discharge at its mouth: 1700 m3 s-1; annual flood: 4000 m3/s), and the primary freshwater input to the western Mediterranean basin. It was mainly an upland river transporting gravel up to its delta and continuously supplied in sediments by its Alpine braided tributaries. The Durance River was one of the most active system before being controlled for producing electricity and supplying water for irrigation. The fluvial landscape has been engineered for more than 150 years, leading to altered aquatic and riparian ecosystems and social tensions in terms of local development scenarios. The channel was regulated between 1850 and 1930 for navigation purposes (embankments, groynes, dykes), then dammed for producing electricity (1898-1986: 21 hydroelectric dams, most of them with derivation canals). It is also equipped with 4 nuclear powerplants that use the river water for their cooling. After more than a century of developments leading to major biological and physical changes due to a significant artificialization of the river corridor, problems and stakes are still existing in terms of human safety, user satisfaction and local development and the aim is now to improve existing conditions and promote a sustainable development, shared by all actors. Today, stakeholders face tension in balancing various user interests regarding nature conservation, flood control, economic and recreational activities, ecological improvement. The French Rhône stakeholders have beencommitted since 2003 in implementing a large inter-regional sustainable development masterplan funded by the European Union (ERDF) called Plan Rhône I and II, focused on the whole river corridor. They created a collective framework grouping local actors to go beyond the complex and sometimes contradictory logics of each of them