DSS application at a river basin scale, taking into account water resources exploitation risks and associated costs: The Algarve Region

The increase on water demand of the different sectors lately so commonly verified, namely for domestic use, has been a major incentive towards the development and use of Decision Support Systems (DSS). In the context of a European Project, a DSS tool was developed and applied to the Algarve region, in Portugal, having as major purpose the sustainable management of the water resources existing in the whole region. Different strategies (combinations of water management options) were defined and evaluated using the DSS tool aiming at minimizing the existing and foreseen water deficits in the region having in mind the requirements specified by the Water Framework Directive (WFD). A performance assessment of strategies and an economic analysis embracing direct and environmental costs computed by the tool do enable selection of strategies. The results of the evaluation of two strategies to minimize regional ground and surface water resources exploitation risks and costs are presented. The specific case of the Querença-Silves aquifer's exploitation is addressed, as it is the most important (in quantity, quality and pressures due to current and potential future use) of the Algarve region.