The Effects of Groundwater Pumping and Infiltration on Seawater Intrusion in Coastal Aquifer

Lee, H.; Kim, S.; Jun, K.W.; Park, H.K., and Park, J.S., 2016. The Effects of Groundwater Pumping and Infiltration on Seawater Intrusion in Coastal Aquifer. In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 652–656. Coconut Creek (Florida), ISSN 0749-0208.The purpose of this study is to identify the characteristics of seawater intrusion; an examination was carried out of the impacts of groundwater pumping and infiltration by precipitation on the seawater intrusion in coastal aquifers. To simulate seawater intrusion, three layers (layers 1, 2 and 3) were identified based on a drilling log. The infiltration rate of 30 years of rainfall data was calculated as 26.43%. The change of salt concentration was simulated using the FEMWATER model by considering the infiltration rate and assuming the pumping rate as 185m3/day for 300 days. The proportion of transverse dispersivity towards the longitudinal dispersivity was changed from 1/10 to 4/10; in the four cases, the total dissolved solids (TDS) were plotted to compare the observed concentrations. The simulation was performed for the following four cases: no infiltration-no pumping, infiltration-no pumping, no infiltration-pumping, and infiltration-pumping. In the initial stage, the simulated concentrations and observed concentrations of dispersivity for each case showed similar trends; however, after the 100 day period the simulated concentration began to show an underrated tendency. For the no infiltration-no pumping case, the simulated concentrations and the observed concentrations of dispersivity exhibited similar appearances at 3/10.