Numerical Modeling ofSeawater Intrusion Management Measures

Abstract

Overexploitati oofn coastal aquifers has become a common issu ewith many coasta1 regions experiencing extensive seawater intmsio rnes,ulting i nsevere deteriorat ioofgnroundwater qualit yW.hen analyzing the freshwater qualit yextracted from the pumping wells in coastal aquifers, the movement of very iow concentrations of the solute is critical in analyzing the level of contamination in pumping wells, This researeh analyzes the effectiveness of four seawater control measures using a hypethetic aslteady-state salt distributi moondel in a representative cross-section perpendicul arto the coastline using a two-dimensional density-depende ntsolute transport model through homogeneous media, It is established that the shallow pumping wells are more preferabl ethan the deep pumping wells as they have relatively lower concentration value in the pumping well, Low permeable aquifers give high concentration values in thc pumping well and the extent ofseawater intrusi oins larg cthan the high perrneabl oenes. The leve lofcontamination in the pumping well is proportion atlo the extent of seawater intrusio wnedge. Pumping wells locate dfurth earway from the seashore are not affected by the presenc eof the seawater intrusio wnedge; however, this may not bc an effective method ofcontrolling seawater intrusio Dn.eep recharge wells closer to the pumping well seem to be the most effective method ofcontrolling the extent ofseawater intrusio annd the concentration value in tlie pumping well. Deep seawater pumping wells located relatively away from the pumping well could be used to cDntrol seawater intmsion if proper disposa lmethods fo rthe extracted saltwater are implemented .Low permeable barrier walls locate dcloser to the pumping well could be used, although the initi acolst of constmction may be high.