Résumé
Many catchments in southern France are facing imbalance between available water resources and demand (in particular for irrigation purpose). Furthermore, the implementation of the EU Water Framework Directive (WFD) has led to revise water abstraction authorizations in order to achieve good ecological status for all water bodies by 2015. These decisions are giving rise to conflicts among users and between users and water management authorities. In such context it seems important to compare economic benefits related to irrigation (agricultural production, employment) with environmental costs due to excessive water abstractions, and more generally environmental impacts of irrigation. The Ecosystem Services Approach enables a holistic analysis of present and potential benefit derived from aquatic ecosystem functioning. It also helps to identify trade-offs and synergies among them as well as to improve the economic justification of water management incentives to implement the WFD. Environmental values are frequently assessed thanks to instrumental methods such as stated preferences approaches. However, these methods are increasingly criticized for assuming that monetarization can encompass the multiple dimensions of values that people actually support. To overcome such limitations, the concepts of shared or social values have been recently advocated to designate non utilitarian dimensions of ecosystem values that are articulated in the frame of social processes. This suggests that value elicitation can be channeled not only through quantitative methods, but also qualitative methods. Deliberative Monetary Valuation (DMV) represents the various techniques that were recently developed to combine monetary valuation and participatory workshops in order to elicit the plurality of values that people hold for environmental goods. In this framework, we adopted a mixed valuation method that combines choice experiment (CE) with participatory workshops. Our study focuses on deeply-held values given by local population to water-related ecosystem services and attempts to determine whether and how deliberation influences their individual and/or shared values. This approach is applied to the Gardons river catchment (south east of France), confronted with quantitative and qualitative water management issues. Our protocol comprises two major phases. The first phase consisted in designing the survey instrument and deliberation process and was based on interviews and a workshop with Gardons river stakeholders and experts. We identified 13 ES existing in the catchment and selected the 4 most relevant in order to design the CE survey. This phase also revealed the intricate linkages between cultural and socio-economic dimensions of water uses in this catchment. Consequently, the final design includes three attributes representing the main provisioning and cultural ES (domestic water, tourism, traditional irrigation), and an ecological attribute at the basis of several regulating ES (the river good ecological status). The second phase consists in implementing the questionnaire and organizing deliberative workshops to discuss the principles that should guide water allocation decisions. This phase aims to elicit participants’ values and their willingness to pay for identified benefits provided by the Gardons river ecosystems.