Potentiometric surface of the upper Floridan Aquifer, west-central Florida, September 1986

A September 1986 potentiometric surface map of the Upper Floridan aquifer in west-central Florida depicts water levels for the annual high water level period. Water levels in most wells measured in September 1986 were higher than in May 1986. September levels averaged about 1 foot higher than May levels in latitudes north of the Hillsborough-Pasco County line and about 9 feet higher in southern areas. The average water-level change between September 1985 and September 1986 in individual wells was less than 1 foot. Average water levels in most wells measured in September 1986 were less than 1 foot lower than September 1985 levels in the north and less than 1 foot higher in the south. (USGS)