Waters within the north coastal limestoneaquifers are suitable for public supply, industrial and agricultural uses. For the artesian aquifer and the updip parts of the watertable aquifer, calcium and bicarbonate are the dominant ionic species with total dissolved solids and chloride concentrations below 500 and 250 mg/L, respectively. In coastal areas of thewater table aquifer, where a freshwater-saltwater mixing zone occurs, the calcium bicarbonate facie grade to a sodium-chloride facie. Within this zone, concentrations of total dissolved solids and chloride are greater than 250 and 500 mg/L respectively, affecting the suitability of the water for some uses. Geochemical models were constructed to determine the physical and chemicalreasons for the prevailing water quality patterns of the north coastlimestone aquifers. Models indicate that calcite and carbon dioxide dissolution, precipitation or degassing are the primary processes. The mixing of recharge water or saltwater with aquifer waters is an important feature within the water table aquifer. The models provide further evidence that support the circulation of groundwater within the north coast limestone.
