Simulation of regional subsurface flow by finite element models

The numerical models represent very useful tools for the simulation of regional flows and may provide several indications as to a rational management and allocation of the available water resources. The very complex aquifer systems underlying the Friuli-Venezia Giulia Region in northeastern Italy, has been analysed with the aid of two combined models based on the finite element method. The first model simulates the steady flow in the Upper Plain and relies on the Dupit-Forchheimer—Boussinesq approach. The second one simulates the multi-aquifer basin of the Lower Plain and is based on the integro-differential theory of flow. Both models have been run under a series of realistic assumptions properly combined with the limited available information. The results obtained for the dry regime are moderately satisfactory and allow for the first-hand appraisal of the quantity involved in the overall regional groundwater balance. They also point out the need for a substantial improvement in the quality and quantity of the regional subsurface data vis à vis reliable future predictions in a wider framework of practical interest.