The U.S. Geological Survey (USGS) cooperated with Miami-Dade County to map the approximate inland extent of saltwater intrusion in the Biscayne aquifer in eastern Miami-Dade County, Florida in 2022. This map is a continuation of a series of maps, the most recent of which was published in 2018, which have helped to track the position of the saltwater interface over time and have improved understanding of the rate of movement of the saltwater interface. To estimate the position of the saltwater interface, relevant data including chloride concentrations, specific conductance, and bulk conductivity from time-series electromagnetic induction logs collected by various organizations including the Florida Keys Aqueduct Authority (FKAA), Florida Power and Light Company (FPL), MacVicar Consulting Inc., and the USGS were acquired and compiled. These data were entered into a geographic information system for mapping. The approximate location of the saltwater interface is represented by the 1,000-mg/L isochlor at the base of the Biscayne aquifer. The term “approximate” is used here because certain areas of the map lack sufficient spatial distribution of monitoring wells to create a precise representation. This data release includes a shapefile of the 1,000-mg/L isochlor and tables of construction information for wells used to create the map and the maximum chloride concentration in those wells in 2022.
