Improving Water Quantity and Quality Supply Security by Managed Artificial Recharge Technologies in the Lower Llobregat Aquifers Integrated into a Conjunctive Surface and Groundwater Management Scheme for Barcelona, Spain

The large concentration of human population, industry and services in the Metropolitan Area of Barcelona has to confront scarce water resources, serious seasonal and inter-annual variations and quality deficiencies in the sources. A large fraction of these water resources are in the medium-size Llobregat River basin and the remaining ones correspond to a surface water transfer, seawater desalination and wastewater reclamation. Groundwater dominated water resources availability before 1950. Afterwards, water supply has evolved progressively to integrated water resources management, which includes serious water quality concerns to deal with population density, river pollution, seawater intrusion in the main aquifer, and brine generation in the mid Llobregat basin due to old mining of saline minerals. The role of the alluvial aquifers has progressively evolved from being the main water source to reserve storage to cope with seasonal and drought water resources availability. River-enhanced recharge and artificial recharge are needed to assure enough groundwater storage before surface water becomes scarce and/or suffers a serious temporal loss of quality. Enhanced river recharge started in 1950. Treated river water injection in dual-purpose wells was put into operation in the early 1970s. Basin and pond recharge was added later, as well as a deep well injection barrier along the coast to reduce seawater intrusion and to allow increased groundwater abstraction in moments of water scarcity. There is a progressive evolution from solving water quantity problems to consideration of water quality improvement during recharge, with attention to emergent concern pollutants in river water and in reclaimed water to be considered for artificial recharge. Improvement of artificial recharge operation activities has been introduced and research is being carried out on the difficult behavior to degrade organic pollutants during infiltration and in the terrain. This paper presents the different activities carried out and presents the research activities, and comments on the economic, social and administrative issues involved as well.