Effects of Climate Change On the Fresh Groundwater Resources of the Bahamas

Fresh groundwater resources within low-lying island settings, such as the Commonwealth of the Bahamas, typically occur as thin lenses of fresh water floating on top of the denser underlying seawater. The lack of topography in carbonate platform island settings like the Bahamas results in very little surface-water runoff and, therefore, these fresh groundwater supplies often serve as the primary drinking-water source for much of the population. In the Bahamas, Andros Island – the largest of the Bahamian islands – serves as a freshwater supply for other nearby islands and is a key to the water security and tourism industry for the country. These fresh groundwater lenses are extremely vulnerable to the potential effects of climate change such as rising sea level and changes in the frequency and intensity of tropical storms. A new project beginning in 2010 is designed to assess, monitor, and model the dynamic geometry of the freshwater lens on North Andros Island in the Bahamas with the goal of forecasting the effects of incremental sea-level rise, changes in precipitation and aquifer recharge, as well as consider the vulnerability of the resource to storm-surge inundation and saltwater contamination. This project is under the auspices of the United Nations Educational, Scientific, and Cultural Organization (UNESCO) sponsored initiative entitled Groundwater Resource Assessment under the Pressures of Humanity and Climate Change (GRAPHIC). The goal of the GRAPHIC Programme is to raise awareness of the importance of groundwater to the global water supply and to advance research on the effects of climate change and human stressors on global groundwater resources. Because this project is in its early stages, no results are yet available. The presentation will outline the UNESCO GRAPHIC Programme, the vulnerabilities of the Bahamian fresh-groundwater supply, the key resource-management questions to be answered, and the planned scope of study.