IMPROVEMENTS IN SALTWATER-INTRUSION MONITORING TECHNOLOGY AND METHODS (Invited Presentation)

Saltwater intrusion is a widespread issue of concern for water-resource managers and has been linked to groundwater withdrawals for water supply, reductions in fresh-water levels of aquifers, road salting, leakage of saltwater from coastal streams and canals into aquifers, and mobilization of connate or residual invaded saltwater. Saltwater intrusion has rendered some water-supply wells and well fields unusable. Management of well fields near areas with saline groundwater requires proper design, maintenance, and operation of saltwater-intrusion monitoring networks. Examination of the saltwater-intrusion monitoring networks in southern Florida has identified long-standing deficiencies including: (1) lack of coverage near the freshwater/saltwater interface, (2) improper well design for saltwater sampling, and (3) inadequate water sampling or salinity measurement methods or techniques. These deficiencies are likely not limited to south Florida. Saltwater-intrusion monitoring deficiencies can be addressed through: (1) borehole geophysical logging, (2) surface and airborne geophysical surveys, (3) improved well designs, (4) careful consideration of the location of the saltwater interface during network design, (5) refined sampling or measurement methodologies or techniques, and (6) enhanced accessibility to monitoring information through automated analytical websites. Universal application of these techniques and methods could improve the understanding of saltwater intrusion processes.