Potentiometric Surface of the Upper Floridan Aquifer in the St. Johns River Water Management District and Vicinity, Florida

Abstract

Potentiometric surface maps of the Upper Floridan aquifer in the St. Johns River Water Management District and vicinity are published semi-annually as part of a cooperative agreement between the U.S. Geological Survey, St. Johns River Water Management District, South Florida Water Management District, and the Southwest Florida Water Management District. Potentiometric contours are based on water-level measurements collected each May and September at over 550 wells, near the end of the dry and wet seasons, respectively. Some contours are inferred from previous potentiometric-surface maps with larger well networks. The potentiometric surface of the carbonate Upper Floridan aquifer responds mainly to rainfall, and more locally, to groundwater withdrawals and spring flow. Potentiometric-surface highs generally correspond to topographic highs where the aquifer is recharged. Springs and areas of diffuse upward leakage naturally discharge water from the aquifer and are most prevalent along the St. Johns River. Areas of discharge are reflected by depressions in the potentiometric surface. Groundwater withdrawals locally have lowered the potentiometric surface. Groundwater in the Upper Floridan aquifer generally flows from potentiometric highs to potentiometric lows in a direction perpendicular to the contours. 

Archived PotMap Data Files

Each file contains contour shapefiles, water-level elevations, and a .pdf file of the published map. Individual map layers are not included. Formats from map-to-map may be slightly different as methods evolved.

September 2006 - May 2009

Maps contain all relevant Metadata.

May 2000 - May 2006

• Some of the early maps may not have complete attribute tables.
• All contours are projected as geographic NAD27, decimal degrees.
• All water-level elevations reference the NGVD29 datum.