Coastal Aquifers: Saltwater Intrusion and Groundwater Rise (IAHR_2_S1)

Topic

Saltwater intrusion into coastal aquifers is a well-known phenomenon that is aggravated by groundwater pumping, which lowers the groundwater table. Saltwater intrusion has been observed, scrutinized, modelled and methods of combating the further advance of the saltwater front have been proposed and put into action. Natural and anthropogenically increased intrusion can be conceived as two phases of the phenomenon. Despite the water salinity, users, especially farmers, are looking for technologies to turn the brackish/saline water into acceptable quality water mainly for irrigation, given the water availability crisis and high water transfer costs. In other regions agricultural land-use is replaced by urbanization, which leads to a third phase of saltwater intrusion that is often characterized by the rise of the water table. This can be attributed to decreased pumping, reduced evapotranspiration, as well as sea-level rise or land subsidence. The rise of the groundwater table causes several new problems in the affected regions, which are exacerbated by the fact that the rising water is saline. For example, foundations of buildings erected in the early phase of low water tables get damp by saline moisture uptake. Also, saline shallow groundwater seeps into coastal lagoons and depressions affecting eco-systems and favouring mosquito plagues. Research on the third phase of saltwater intrusion is crucial to address these problems.
The saltwater intrusion / groundwater rise (SIGR) combination has not attracted much attention so far but can be expected to get more importance in future. The session is aimed to establish a community that addresses SIGR in all parts of the world.