RESEARCH NEEDS FOR MANAGING COASTAL AQUIFERS IN THE ADVENT OF GLOBAL CHANGE (Invited Presentation)

Coastal groundwater resources are under increasing stress. Sea level rise and a higher incidence of storm surges exacerbate the salinization of fresh groundwater, and changing weather patterns affect rainfall recharge. At the same time, economic growth, rising tourism and increasing population densities in coastal zones push up the demand for water, while pollution from various sources is contaminating groundwater. Coastal hydrogeology research has led to major advancements in the understanding of the processes in coastal groundwater systems, but, in order to safeguard freshwater availability as well as ecosystems, these adverse developments mean that important research needs remain. Questions to be answered include the following. How does seawater flooding impact fresh groundwater? What options exist to store freshwater in saline aquifers? How can brackish groundwater be used for potable water supply? How will changes in weather patterns affect rainfall recharge and the sustainable yield of coastal aquifers? What is the response time of coastal groundwater systems to environmental change? This contribution will address these questions by showing research outcomes from a number of recent projects in Germany and the Netherlands. The results and ideas for solutions to the problems encountered can help to direct research efforts that support the societal challenges in coastal areas in the decades to come.