Figure 7. Photographs of Global Position System (GPS) base station and rover on Dauphin Island, Alabama, in 2013. A, Base station near the entrance of Fort Gaines on the eastern side of Dauphin Island. B, U.S. Geological Survey Scientists surveying the well at site 972 with a GPS rover before recovering the sensor from the well. Erosion of the beach on the Mississippi Sound side of the island beach between deployment and recovery left the top of the well at site 972 exposed.