The extent of saltwater intrusion in southern Baldwin County, Alabama

Abstract

Contamination of groundwater due to saltwater intrusion has become a major concern for coastal communities which rely on groundwater as their principal source of drinking water. The protection of groundwater resources from saltwater intrusion and groundwater overdraft is a critical concern in these areas as both groundwater resources and environmentally sensitive areas such as coastal wetlands and ecological coastal habitats may be at risk. A regional-scale study was conducted to assess the extent of saltwater intrusion for Baldwin County, Alabama. Groundwater wells were sampled and analyzed for salinity, chloride (Cl⁻), total dissolved solids (TDS), and other parameters to determine the extent of saltwater intrusion, and the location of the freshwater/saltwater interface in the region. Spatial iso-concentration maps (i.e. salinity, Cl⁻, and TDS) were constructed using ArcGIS software to determine the extent and severity of saltwater intrusion for the aquifers underlying southern Baldwin County. Concentration data show relatively low salinity levels in the central and northern extent of the study area. Elevated levels of salinity, Cl⁻, and TDS were observed in the local aquifers A1 and A2 along the coastal areas adjacent to the Gulf of Mexico. The study provides an initial current data set of areas impacted or most vulnerable to saltwater intrusion and provides a scientific basis for effective management of the coastal aquifers in the study region.