The surficial aquifer system, in which an unconfined groundwater flow system exists, comprises the sediments from land surface to the intermediate confining unit (formerly called the Floridan aquiclude) in Broward County, Florida. These sediments have hydraulic conductivities that range more than seven orders of magnitude from about 0.001 ft/d to more than 10,000 ft/d. The sediments are grouped into (1) the Biscayne aquifer, (2) a semiconfining unit, (3) a gray limestone aquifer in west Broward County, and (4) basal sand or clayey sand. The system is about 160 ft thick in west Broward County and more than 350 ft thick in east Broward. Transmissivities, locally variable, show a clear areal trend from greater than 300,000 sq ft/day in southeast Broward County to less than 75,000 sq ft/day in the northwest part of the county. Very high transmissivity is associated with the Biscayne aquifer. Transmissivity of the gray limestone aquifer ranged from about 20,000 to 88,000 sq ft/day. Topography, water levels, geologic framework, and water quality in west Broward County suggest past and present groundwater movement is south or southeast. Drainage and urban development have greatly altered circulation patterns in east Broward County , eliminating the original coastal groundwater ridge, causing rapid surface runoff and short groundwater flow paths, and saltwater intrusion. (USGS)
