Six proposed injection sites are located in Pinellas County, Fla., and the city of St. Petersburg. Projected maximum injection rate, if all sites become operational, will be about 40 million gallons per day. The injection zone at the proposed sites is in a consistently dolomitized section of the Avon Park Limestone in the lower part of the Floridan aquifer. The injection zone contains saline ground water that has a chloride concentration of 19,000 to 20,000 milligrams per liter. Pressure and velocity changes were computed at selected regional locations in the upper and lower parts of the Floridan aquifer. Results of the model computations suggest that the regional impact after 20 years of injection will be small. Three locations are proposed for regional monitoring of subsurface injection. They are in the vicinity of the intersection of highways U.S. 19 and U.S. 60 in Pinellas County, Sun City in Hillsborough County, and the intersection of Sheldon Road and Gunn Highway in Hillsborough County. (USGS)