Experimental Investigation Of Seawater Intrusion In Unconfined Coastal Aquifers

Experiments are conducted in a two dimensional sandbox. The influences ofseaward boundary, landward boundary, pumping above saltwater-freshwater interfaceand sinusoidal tide on seawater intrusion are investigated respectively. Theconclusions are as follows:(1) The saltwater wedge move inland of which the saltwater-freshwater interfaceis clear. The saltwater-freshwater interface is linear during initial period, and paraboliceventually.(2) The rate of change of saltwater wedge’s length and area can indicate the endpoint of seawater intrusion(3) The flux of landward boundary and the length of freshwater discharge zone islinearly dependent.(4) The saltwater upconing is close to the seaward boundary instead of below thepumping well and pumping can increase the extent of seawater intrusion.(5) Compared with the formation of saltwater upconing, the decay of saltwaterupconing is rapid relatively and the saltwater wedge can return to the state beforepumping after pumping is stopped approximatively.(6) The change of saltwater wedge’s length lags behind the change of saltwaterwedge’s area on the basis of overall trend during pumping period or after pumping isstopped.(7) Salt transport associated with this seawater circulation leads to the formationof an upper saline plume (USP) within the intertidal zone. The overall seawaterintrusion extent, as indicated by the wedge toe location, was reduced significantlycompared with the nontidal(static) case.