A sequence stratigraphic based geological model for constraining hydrogeological modeling in the urbanized area of the Quaternary Besòs delta (NW Mediterranean coast, Spain)

The Quaternary Besòs delta is located on the Mediterranean coast in NE Spain. The Besòs Delta Complex includes 3 aquifers constituted by 3 sandy and gravelly bodies, separated by lutitic units. These aquifers supply water for domestic and industrial use in this area. Management of groundwater has been problematic in the Besòs delta since the 1960s, and continues to pose major problems for subsurface engineering works in this highly urbanized region. This study seeks to demonstrate the advantages of detailed geological characterization and modeling for designing and constructing a hydrogeological model. Available information of the subsurface was compiled, integrated and homogenized in a geospatial database. The interpretation of these data enabled us to delimit geological units by means of a sequence stratigraphic subdivision. A three-dimensional facies belt-based model of the Besòs delta was built on the basis of this geological characterization. This model was used to constrain the distribution of hydraulic parameters and thus to obtain a consistent hydrogeological model of the delta, which was calibrated by data of water management and production over the last hundred years. The resulting hydrogeological model yielded new insights into water front displacements in the aquifer during the time-span considered, improving predictions in an attempt to optimize aquifer management.