Saltwater Intrusion Management and Water Resource Development
Hilton Head Public Service District, Hilton Head Island, SC

GMA began working for the Hilton Head Public Service District (Hilton Head) in 2005 during the preparation of a Water Resources Master Plan. GMA continues to work with Hilton Head to monitor ongoing saltwater intrusion into the Upper Floridan Aquifer. GMA helped Hilton Headed evaluate and develop a wellfield in the brackish Middle Floridan Aquifer to supply 4 million gallons per day (MGD) of source water to their Reverse Osmosis Water Treatment Plant.  The development and permitting this wellfield required detailed aquifer testing and 3-dimensional groundwater modeling to address regulatory concerns about potential impacts to fresh groundwater in the overlying Upper Floridan Aquifer. GMA helped Hilton Head construct and test an Aquifer Storage Recovery (ASR) well open to the Middle Floridan Aquifer that is capable of recovering water at 2.88 MGD. This ASR well allows Hilton Head to seasonally store and recover approximately 350 million gallons of treated drinking water each year. Hilton Head initiated their second ASR well project in late-2014, and the project is presently in the permitting and funding stage.  We expect that on-site work will begin in late-2015. GMA’s services to the Hilton Head Public Service District are ongoing.