Potentiometric surface of the upper Floridan Aquifer, west-central Florida, May 1987

A May 1987 potentiometric surface map of the Upper Floridan aquifer in west-central Florida depicts water levels for the annual low water-level period. Water levels in most wells measured in May 1987 were lower than in September 1986. May levels averaged about 0.5 foot higher than September levels in latitudes north of the Hillsborough-Pasco County line and about 6 feet lower in southern areas. The average water-level change between May 1986 and May 1987 in individual wells was more than 3 feet. Average water levels in most wells measured in May 1987 were more than 2 feet higher than May 1986 levels in the north and more than 4 feet higher in the south. (USGS)