Progress report on the water resources investigation of Martin County, Florida

Abstract

The base of the shallow aquifer ranges from 125 feet (38 m) below sea level in the northwest part of Martin County to about 280 feet (85.3 m) below sea level in the southeast part of the county. Test holes also indicate a thick, highly permeable zone in the east part of the county which becomes thinner and interlaced with zones of lower permeability in the west part. Water levels decline about 2 to 5 feet (0.6 to 1.5 m) during the dry season (October 1973 to May 1974) in most areas of Martin County. Within the area influenced by the pumping of Stuart's public supply wells, water level declined 6 feet (1.8 m) between October 1973 and May 1974. Water levels during January - May 1974 in this area were 3 to 6 feet (0.0 to 1.8 m) lower than they were in January - May 1965. This difference was due to a three-fold increase in pumpage (0.8 to 2 mgd) from 1965 to 1974. Chloride concentrations in four salt water monitoring wells around the Stuart well field ranged from 35 to 45 mg/1 during the rainy season of 1973. No appreciative increase in chlorides was found by the end of the next dry season. Water from five surface water sites had higher concentrations of phosphorus than water found in a typical urban area in Fort Lauderdale. Water from seven sites contained concentrations of nitrogen less than the typical rural site average. Expansion of the test drilling program, observation of salt-water intrusion, water-level monitoring and continued nutrient sampling are planned for future study. An interpretative report will be prepared at the end of this investigation.