These resources must be used in a judicious manner if we are to live within our means. Meeting the needs for providing potable water to 75% of humanity from such a limited resource forms a major global challenge facing society in the 21st Century.

Groundwater has been recognised for some time for its capacity to provide good quality water, particularity in places where other water sources have either poor quality, requiring expensive (and environmentally unfriendly) treatment technologies, or are unavailable. However, it needs to be used cautiously. Over-pumping of coastal aquifers can lead to seawater contaminating groundwater supplies, thereby destroying otherwise valuable resources. Contamination by even 1% salt water can be enough to render freshwater unfit for use. This issue is of concern in the UK, where saline intrusion (SI) can affect the quality of water used for human consumption, as well as for industrial purposes (process water and irrigation). Further afield, this matter is of pressing concern across Europe, particularly in Mediterranean countries, as well as in other water-stressed arid and semi-arid regions of the planet where use of desalinisation technologies may not be viable over the long term.

The overall aims of our research are to improve current understanding of the physical processes that govern saline intrusion movement in coastal aquifers and develop early warning protocols for saltwater intrusion into abstraction wells. The research team at Queens of 2 Postdoctoral Research Assistants, 1 Research Assistant and 2 PhD students is led by Professor Gerard Hamill and Dr Ray Flynn. They have established ground-breaking techniques by which the processes at play within a coastal aquifer can be modelled (both experimentally and numerically) and have established one of the first field scale monitoring and testing facilities to aid their investigations at their test near Magilligan.

Variations in coastal aquifer subsurface resistivity over a tidal cycle monitored using ERT:
https://youtu.be/i8kB12WFLuA
An animation showing how the resistivity of the sands at the Magilligan test site change varies throughout a pumping test using the PRIME geophysics system. Red areas indicate freshwater, while blue areas indicate saltwater intrusion, or dewatering.
 
Pumping-induced saline intrusion in a coastal aquifer monitored using ERT:
https://youtu.be/GlGqNAXpS-8
An animation showing how the resistivity of the sands at the Magilligan test site change varies over the course of a full tidal cycle using the PRIME geophysics system. Red areas indicate where freshwater becomes dominant, while red areas indicate where saltwater becomes dominant, as the intertidal recirculation cell waxes and wanes.