As Greece searches for oil and natural gas off its coast, an unexpected discovery could prove even more valuable than the fossil fuels. A team of geologists from the University of Malta has identified a vast underground reserve of freshwater beneath the seabed of the Gulf of Corinth – a reservoir that could potentially meet the country’s water needs for decades to come.
Led by geologist Dr. Senai Khopozal, the team used a combination of deep drilling, seismic imaging, and computer models to map a large-scale system of underground water basins. The results of the study were published in the specialized issue of the Journal of Hydrogeology and reveal a new understanding of so-called offshore confined groundwater (OCG) – freshwater systems stored under the seabed.
Ice Age Footprints
According to scientists, the aquifers are found at depths between 15 and 700 meters below the seabed. They probably formed during several ice ages, when sea levels were significantly lower than they are today.
During these periods, rainwater and river water seeped into the sediments and became trapped there. The slightly porous layers of sand and clay acted as a natural “capsule” that preserved the freshwater for about 800,000 years.
“These geological structures are like time capsules – they preserve freshwater from times when the sea level was tens of meters lower,” explains Dr. Xopozal.
One of the largest freshwater reservoirs in the world
The discovered underground basins beneath the Gulf of Corinth are estimated to hold about 250 cubic kilometers of freshwater – a volume that places the system among the largest such discoveries in the world.
In comparison, this amount is enough to satisfy the drinking needs of all of Greece for at least two decades.
Similar deposits have been identified in other parts of the world – for example, off New England (USA) and New Zealand, but so far no reservoir of this size has been discovered in the Mediterranean.
Greece’s water crisis
The discovery comes at a critical moment. In recent years, Greece has been facing increasing water shortages – the result of more frequent droughts, rising temperatures and intense tourist pressure.
Water consumption in the country has more than doubled in the last 25 years – from 800 million to 1.8 billion cubic meters per year.
The situation in Athens, home to around 4 million people, is particularly worrying. Water levels in the main reservoirs supplying the capital are falling sharply. For example, the Mornos Dam, the largest in the country, has decreased from over 670 million cubic meters in 2021 to under 150 million today – an amount that could cover the city’s needs for just two years.
Government responds: infrastructure for millions
In an attempt to ensure stable water supplies, the Greek government has already announced a €535 million project to build tunnels and canals that will transport water from rivers in Central Greece to Athens. The project is due to be completed by 2029 and is expected to guarantee the capital’s water supply for the next 3 decades.
However, thanks to the discovery under the Gulf of Corinth, the country could have an alternative and sustainable reserve – a natural underground source, which would reduce dependence on climate cycles and infrastructure limitations.
The researchers point out that some of the freshwater deposits under the bay are exceptionally shallow – in some areas only 15 to 100 meters below the seabed. This makes them relatively accessible for mining, but also susceptible to environmental risks.
“It is possible that this water can be used for the needs of the population, but any exploitation must be carefully regulated,” the scientists warn.
Improper extraction can lead to salt infiltration or disruption of the natural balance of groundwater – consequences that could render the systems irreversibly unusable.
The discovery of underground freshwater reserves under the Gulf of Corinth has the potential to turn them into a geostrategic asset for Greece. In the context of climate uncertainty, growing tourism, and the need for energy and resource independence, access to stable water sources may prove more valuable than oil.
In addition, the research lays the foundation for new technologies for offshore freshwater extraction – a sector that will soon gain economic significance on a global scale.
Illustrative photo: marc-olivier-jodoin-TStNU7H4UEE-unsplash
