Water resources of Manatee County, Florida

Rapid development of Manatee County in southwest Florida is creating water-resource problems. This report presents an evaluation of the water resources and potential effects of water-resource developments. Most streams in the county have small drainage basins and minimal flow. Streamflow is variable with the base flow occurring from November to May. The Manattee River and its largest tributary, the Braden River, are the principal sources of public supplies. Surface water is generally of good quality and less mineralized than ground water except in the tidally affected and coastal area. The principal aquifers in the county are the surficial, minor artesian, and the Floridan. The Floridan aquifer is the major source of irrigation water in the county. The minor artesian aquifer is a highly developed source of water for small rural supplies. Withdrawals of 20 to 50 million gallons per fay from the Floridan aquifer since the 1950 's have caused declines in the potentiometric surface of about 20 to 50 feet. The quality of ground water is good except in the coastal and southern parts of the county. Water in the Floridan aquifer is generally more mineralized than the other aquifers, generally increasing in mineral content with depth and from the northeast towards the southwest. (USGS)