In the 1992 Rio World Summit on Environment and Development/UNCED), water resources are indicated to remain at the core of sustainable development and, thus, they are to be managed and developed on a sustainable basis. Sustainability is a philosophical concept and thus difficult to measure. Yet, we need to describe it on rather precise terms to assess whether our water management practices are sustainable and to ensure sustainability in decision making for management. To this end, a number of sustainability criteria have been defined, based on quantifiable measures, without overlooking immeasurable aspects of sustainable development. This paper considers economic, social and environmental dimensions of sustainability as the basic criteria to be pursued in evaluating how effective our water management plans are in achieving sustainability. On the other hand, actual case studies are needed to test the usefulness of selected criteria by using computer-based interactive optimization and simulation models with associated databases embedded into a decision support system (DSS). The study herein intends to present such a case study based on economic, social and environmental criteria to assess sustainability in management of the Gediz River Basin in Turkey. Various management scenarios developed for the basin are evaluated within a DSS while ensuring multi-stakeholder involvement in defining the three sustainability criteria. The case study is a result of the analyses carried out in SMART (Sustainable Management of Scarce Resources in the Coastal Zone) and OPTIMA (Optimization for Sustainable Water Resources Management) projects funded respectively by the 5th and 6th Framework Programmes of the European Union.
