EDITOR'S NOTE: This is 1 of 12 papers prepared by participants attending the workshop “Risk Assessment in European River Basins–State of the Art and Future Challenges” held in Liepzig, Germany on 12–14 November 2007. The meeting was organized within the framework of the European Commission's Coordination Action RISKBASE program. The objective of RISKBASE is to review and synthesize the outcome of European Commission FP4–FP6 projects, and other major initiatives, related to integrated risk assessment–based management of the water/sediment/soil environment at the river basin scale.

The Mediterranean region has an extensive hydraulic infrastructure and complex socioeconomic interactions among water users. In this region, competition for water among urban, agricultural, industrial, and environmental demands is strongest in times of water scarcity. Allocation of scarce water in the face of multiple demands is a challenging task that requires careful analysis. Precipitation decreases may likely be translated into drought periods in most cases. Nevertheless water scarcity (the shortage of water resources to serve water demands) not only depends on drought or precipitation deficits but also on water management. Adaptation options depend on the strategic contingency planning and management decisions that affect water resources systems. The risk management of water scarcity and drought depends on the level of water scarcity. Therefore, an adequate diagnosis of the water scarcity level is essential to anticipate the possible solutions. This study proposes a methodology for drought risk management based on the evaluation of 4 indicators of water scarcity to be used to define the thresholds of risk management actions. Based on the definition of thresholds, the study proposes the implementation of risk management actions that may be used for responding to each water scarcity situation.