Wu, X.; Xu, Z.; Xu, Z.; Hu, B.X.; Chang, Q., and Hu, Y., 2022. The influence of seasonal recharge and groundwater pumping on the seawater intrusion in a coastal karst aquifer. Journal of Coastal Research, 38(4), 785–794. Coconut Creek (Florida), ISSN 0749-0208.
Groundwater resources in the coastal karst aquifers are threatened by long-distance seawater intrusion. The severity of groundwater contamination can be affected by hydrologic and anthropogenic factors, including rainfall conditions and pumping situations. A better understanding of these factors' control on the seawater intrusion is critical for their vulnerability estimation and aquifer management. The aquifer salinization, pumping safety, and the vulnerability of inland springs were examined by a synthetic-modeling work in this study. Different pumping locations, pumping rates, the comparison of dynamic seasonal recharge (DSR), and steady-state recharge (SSR) were considered in this study. Several time-based metrics were developed to estimate the aquifer vulnerability and water quality. The results show that the distance of pumping location to the shoreline significantly impacts seawater intrusion. The near-shore pumping leads to lower aquifer contamination while higher salinity in pumped water, and the inland pumping causes more aquifer salinization with cleaner pumped water. In addition, aquifer, pumping water quality, and inland spring are more vulnerable to seawater intrusion under the DSR condition than SSR condition. The difference of aquifer salinization between DSR and SSR condition increases with pumping rate from 50 to 150 m3/day and then decreases from 150 to 200 m3/day, which shows a threshold pumping rate in comparing DSR and SSR conditions. The insights from this work provide essential suggestions for groundwater simulations and related management decisions.