چكيده لاتين :
A numerical model was developed to evaluate the response ofgroundwater flow and the fresh-saltwater
interface in relation to the construction of a particle accelerator at the coastal plain of Tokaimura, Japan. Undisturbed
conditions were initially simulated and validated against field observations as a prerequisite for the analysis of predictive
scenarios. Groundwater heads and the shape of the saltwater interface were appropriately described by the model,
although it tended to underestimate salinity concentrations. Saltwater penetrated up to 250 m inland during predevelopment
conditions, reaching more than 400 m at the dewatering phase. Flushing of entrapped saline groundwater might occur in
addition to seawater intrusion. In depth, multiple saltwater fronts develop in response to the hydraulic properties of
the sediments. Groundwater discharges offshore through the sandy aquifers, but salinity fronts prevail in the relatively
impermeable layers. Routes for freshwater outflow turned into pathways of seawater intrusion during the pumping
phase. The equilibrium would be reestablished within 2 years from the end of the stress, with no evidence of a
permanent deterioration of neighbor residential wells. Nonetheless, after construction the accelerator forms a barrier
that leads to a sharp rise in piezometric levels and creates a new and long-term disequilibrium in the saltwater wedge.
Despite further work is still necessary to test many of the ideas proposed, the present study makes a new contribution
to enhance the understanding of the processes occurring in coastal aquifers subjected to anthropogenic influence.
