From Traditional to Sustainable Water Management: New Approaches and Tools in Line with the European Water Framework Directive

The paper describes how the concept of sustainability has modified our vision of water resources development strategies and discusses the tools needed to take it into account. Essentially, the sustainability concept implies that water must not be regarded anymore as an unlimited resource to be exploited, but as a limiting factor for development. Recently, the European Water Framework Directive also introduced the concepts of demand management and environmental costs to be taken into account in the planning phase as a means to reach sustainability. Finally, the planet is threatened by climatic changes that may induce dramatic effects in several parts of the world. The need for taking into account all these issues, has given rise to the need for integrating the physical components of availability, demand and delivery of water into comprehensive simulation systems describing the interactive relations among the physical, the social, the economical and the environmental aspects of the water allocation problem. Therefore, from the optimisation techniques of the eighties, which results could be hardly understood by the stakeholders, the new tendencies aim at describing the consequences of possible interventions in terms of indicators ranging from simple physical and chemical to the complex environmental and socio-economical ones.