USGS Grant Number:
Year Established: 2007 Start Date: 2008-04-01 End Date: 2011-09-30
Total Federal Funds: $194,083 Total Non-Federal Funds: $194,346
Principal Investigators: Jian Luo, Jian Luo
Abstract: Seawater intrusion causes salinization of fresh groundwater resources in costal aquifers, exacerbating the stresses on vital water resources in populated coastal areas. For example, in the coastal area of Georgia (GA), South Carolina (SC), and Florida (FL), increased groundwater withdrawal has substantially lowered the groundwater level and allowed seawater to seep into the freshwater supply. To achieve sound understanding of the transport processes that control seawater intrusion, we outline an ambitious and comprehensive research plan to systematically study seawater intrusion by conducting laboratory experiments, numerical, stochastic, and geostatistical analyses to examine seawater intrusion over various scales ranging from pore grain scale to field scale. The fully compressible NavierStokes equations will be solved for a two-dimensional, symmetric, channel, comprised of a sequence of pores and for pore-networks to investigate the mixing effects of diffusion and density-driven convection at pore scale and Darcys scale. Laboratory experiments will be conducted under various hydrogeologic conditions, including formation heterogeneity, groundwater withdrawal, and transient tidal effects, to identify the relative importance of the contributions of these mechanisms for the development of the mixing zone of saltwater and freshwater. The framework of Henrys problem will be modified to incorporate the elements considered in the experiments. Homogenization approaches will be developed for upscaling effective transport parameters in heterogeneous coastal aquifers. Multivariate geostatistical methods will be used to analyze the field data in the coastal area of Georgia to identify the correlations among groundwater levels, seawater levels, and chloride concentrations, etc., and to examine the existence of characteristic spatial and temporal scales. The proposed research plans have the potential to make significant contributions to understand transport and mixing processes in seawater intrusion, to improve numerical simulations in heterogeneous coastal aquifers, and to provide invaluable information for effective groundwater resources management in the coastal area of Georgia.