This book details theexperiences gained by the Catalan Water Agency (ACA) in a Mediterraneanwatershed – the Catalan River Basin District – following the launch of the EUWater Framework Directive (WFD) in the year 2000. Experts in rivers,reservoirs, lakes, wetlands and estuaries present 13 chapters defining toolsfor water-status assessment specially adapted to Mediterranean conditions. Thecontent of this and the companion volume Experiencesfrom Ground, Coastal and Transitional Water Quality Monitoring: The EU WaterFramework Directive Implementation in the Catalan River Basin District (PartII) are the result of an excellent collaboration between the ACA andseveral Catalan universities and research centers to cope with new challengesprovided by the WFD monitoring requirements. The volume serves as a usefulguide for environmental managers and scientists engaged in other European aswell as Non-European river basins.