Helicopter EM mapping of saltwater intrusion in Everglades National Park, Florida

Abstract

Helicopter electromagnetic surveys are being used to map saltwater intrusion in Everglades National Park, Florida. Using layered earth inversion methods, resistivity-depth slices are generated which provide information on the location of the freshwater/saltwater interface, as well as showing the influence of canals and roadbeds on the hydrologic regime. Through the use of well logs and time-domain electromagnetic soundings, correlations between formation resistivity and water specific conductance have been established. As a result, the interpreted resistivity maps can be used as estimated water quality maps with better coverage than is possible from well sampling alone. Repeat surveys provide means of assessing long term changes in the aquifer system resulting from changes in water management policies aimed at restoring the South Florida ecosystem.