Influence zone of recharging-dewatering actions in an unconfined aquifer

This work deals with the recharging-dewatering problem for an unconfined aquifer. In particular, the evolution of the aquifer free surface consequent to changes in the water level in a trench near the aquifer itself has been investigated. The problem has been analyzed using a numerical approach so as not to eliminate the nonlinearities of the boundary conditions: the Laplace equation has been solved using the finite-element method coupled to an interpolation-collocation method for the solution of the free surface kinematic condition. Many configurations, which are most likely to cover cases of practical interest, have been studied, and the results have been summarized in a simple formula that permits the evaluation of the aquifer portion that is affected by recharging-dewatering actions.