The PSD constructed the island’s first-ever Aquifer Storage & Recovery (ASR) well inside Hilton Head Plantation in 2011. The well both stores and withdraws drinking water. During the winter months of low water demand, the PSD takes advantage of a reduced wholesale water rate from BJWSA and stores treated Savannah River surface water in the Middle Floridan Aquifer using the ASR well. Then, in the summer months when drinking water demand and the wholesale water rate increase, the ASR well is used to withdraw and re-treat 2 MGD of drinking water.
The ASR process involved the PSD injecting 240 million gallons of treated surface water into the 600-foot-deep Middle Floridan Aquifer to build a bubble of fresh water in the brackish aquifer. The fresh water displaces the brackish water and a buffer zone is created at the edges of the fresh water bubble. When the ASR well is used to withdraw water, the water is drawn from the center of the fresh water bubble.