Résumé
For neo-classical economists, markets are seen as the appropriate mechanisms to allocate resources efficiently among users. To respond to the increasing scarcity of water resources and to the competition between uses, markets are increasingly advocated as possible alternatives to more traditional policy interventions in the water sector. However, the use of markets to allocate water among users is rare and remain controversial. Based on a review of literature, the present article summarizes the theoretical requirements for water markets to function efficiently. In practice, these theoretical requirements are rarely met. Nevertheless water markets have developed under a large range of water resources, institutional and economic environments. To illustrate the diversity of existing water markets, three examples are selected and described in more details: (i) the reallocation of surface water rights below the Colorado Big-Thompson Dam in the State of Colorado (US); (ii) the localized and informal groundwater and surface water markets that take place in irrigation systems in Pakistan; and, (iii) the Water Banks that have been established in 1991 and 1992 in the State of California (US) as emergency measures to cope with severe droughts. Based on the lessons from the literature on water markets, the final section of the paper investigates the potential for water market development in France. The adequation between the recent water law of 1992, the existing setup of the water sector and water markets is discussed for different water resources situations (surface water and groundwater, structural and conjunctural water scarcity). The conclusion section stresses the need for further analysis of existing water markets and allocation mechanisms, to better identify the factors that would favour or inhibit the development of water markets.
Considéré d'un point de vue théorique comme le mécanisme optimal d'allocation des ressources, le marché est rarement utilisé comme instrument de gestion dans le domaine de l'eau. L'article identifie d'abord les conditions nécessaires au bon fonctionnement de marchés de l'eau. Bien que ces conditions soient rarement rencontrées en pratique, des marchés de l'eau existent néanmoins sous des environnements physiques, économiques et institutionnels variés. Le fonctionnement et la diversité de ces marchés sont illustrés par trois exemples : (i), la réallocation de droits d'eau d'un barrage du Colorado ; (ii), les marchés de l'eau localisés et informels des systèmes irrigués du Pakistan ; et (iii) les banques de l'eau établies en 1991 et 1992 en Californie. La question des potentialités de développement de marchés de l'eau en France est finalement abordée au vue des conditions nécessaires au fonctionnement de marchés de l'eau identifiées et des expériences décrites.