The alluvial aquifer of the river Roja in Ventimiglia Numerical flow modelling in temporary regime and instructions concerning transportation

The aquifer modelled in this study is approximately 3 km long and 450-600 m wide and is hosted in Quaternary alluvial and detrital sediments that crop out to the north of Ventimiglia (Liguria, Italy), covering about 2 km2 at the confluence of the Roia river and the Bevera torrent. The aquifer is of strategic regional and crossborder importance, providing drinking water to part of Liguria and the French coast. Starting from a conceptual model of the aquifer, numerical transient regime flow and solute transport models were developed. The two watercourses, and especially the Roia, were found to play a key role in this aquifer system. Analysis of the overall water budget and those of the various sectors showed that exchange of water between the watercourses and the aquifer compensated thevolumes pumped from the wells.