Hydrologic monitoring of a deep-well waste-injection system near Pensacola, Florida, March 1970 - March 1977

This report presents hydraulic and chemical data collected at a deep-well waste-injection system near Pensacola, Florida. Since injection began in July 1963, about 13.3 billion gallons of industrial acidic waste containing nitric acid, inorganic salts and numerous organic compounds have been injected into a saline-water-filled limestone aquifer. Wellhead pressure at two injection wells averaged 180 pounds per square inch in March 1977 and the hydraulic pressure gradient was 0.53 pound per square inch per foot of depth to the top of the injection zone. Increases in pressure since 1970 at two wells used to monitor the injection zone at sites located 1.9 miles north and 1.5 miles south of the injection site have been about 22 and 29 pounds per square inch. The pressure in a shallow monitor well, penetrating the first permeable zone above the 220-foot-thick confining bed, declined about 4 pounds per square inch. No changes were detected in the chemical character of water from the shallow monitor well and the north monitor well, but since late 1973, concentrations of bicarbonate and dissolved organic carbon in water from the south monitor well have increased. (Woodard-USGS)