Territoire en Mouvement (Mar 2015)
Adaptation aux changements par renaturation dans une zone humide littorale, le delta du Rhône (France du sud). Une réponse à l’épuisement d’une gestion concertée de l’eau ?
Abstract
Integrated water management of the Rhone delta is facing a considerable set of issues: agricultural inputs draining directly into a national nature reserve, the management of natural risks (floods) and of the global change (sea-level rise), a transit space of migratory species threatened of extinction (eels), safeguarding economic activities (fishing)All those issues involve the management of the deltaic, central lagoons, the “Vaccarès system”, which communicates with the sea and whose salinity and levels are critical for all uses.The public actors’ constant efforts to improve the integrated management of practices have failed to overcome those constraints and now seem to reach a limit, if not exhaustion, especially if the sea level keeps on rising. Nevertheless, a new event recently came to question this relatively pessimistic understanding of the situation by suggesting the possibility of an alternative and original water management. Following the abandonment of industrial salt mining in the south-east of the Camargue, the ancient salt basins have been acquired by the Conservatoire du Littoral (a french public fund dedicated to the conservation of seashores). The main involved environmental managers and public actors have been pleading for the possibility of a "laissez-faire" (i.e., "living nature" perspective) given to nature upon these territories. This implies the reconstruction of several ancient hydraulic connections to improve the evacuation capacities of the Vaccarès hydrosystem and thus increase the biological exchanges. The authors question two management scenarios in order to discuss the ability of ecological restoration to contribute to the adaptation of the Rhone delta to global change. A reflection about options of improving the main hydraulic system’s outlet through greater technical sophistication is also conducted. Far from being returned back to back renaturation and technical design of the system can be complementary in the pursuit of a common goal.
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