Groundwater exchange betwen the Tiber River alluvial Valley and surrounding aquifers in the urban area of Rome (Italy) though the development of a numerical model

Abstract As established in the European Water Framework Directive (WFD, 2000), the study of aquifers from a quantitative point of view is fundamental for adopting water management plans aimed at preserving the water resource and at reducing environmental risks. In this paper authors present a first approach to hydrogeological numerical modeling of the urban and sub-urban city of Rome at sub-basin scale. The model ROMA is a 3D, steady state numerical model covering an area of 237 km2, implemented by the finite-difference code MODFLOW 2000®. The alluvial aquifer of the Tiber River Valley, which runs in the middle of the City in a NNW-SE direction, has been analyzed in detail, since it is covered by a densely populated area hosting mostly of the Rome’s historical heritage, and it is characterized by low quality geotechnical parameters. The implementation of a numerical model allowed to verify the conceptual model, reduce the uncertainty related to the main components of water budget, especially recharge in urban areas and water abstraction rates, and to set the base for future local scale models.