Scientists from the Division for Water Resources Planning and Investigation for southern Vietnam have discovered an underwater source of fresh water using a two-dimensional (2D) electrical imaging method.

The discovery came out of the first research project conducted to look for undersea fresh water called "Study and application of complex geophysical, geological and hydrogeological methods for finding fresh water aquifers in coastal zones (up to 3m sea water depth) and experiments in Bac Lieu province coastal zones", said Dr Nguyen Hong Bang, the project manager.

The 1 billion VND (52,000 USD) project was funded by the Ministry of Natural Resources and Environment.

The fresh water was discovered during a two-year survey at a depth ranging from 48-106 metres, 3kilometres off the coast of Bac Lieu.

The division has submitted a new proposal to the ministry that would help identify the volume of water available and design an exploitation scheme to help meet domestic fresh water needs, Bang said.

He said the completed study also served as a model for the application of science and technology to successfully implement the National Ocean Strategies which were approved by the Prime Minister four years ago.

Bang proposed two more projects to explore other potential undersea fresh water resources. One region is Hai Hau-Nghia Hung in northern Nam Dinh province and the other is the coastal area spreading from Long Toan district in the Mekong Delta's Tra Vinh province to Dam Doi district in southernmost Ca Mau province.

A 2D electrical imaging machine which collected highly accurate data was chosen for its accuracy and for the fact that it helps ensure environmentally friendly exploration.

The 2D imagery showed a cross-section of the area with clear differentiation between high and low resistivity zones, said Dr Bang.

Scientists chose a location three kilometres offshore to bury electrodes in the sea bed every 20 meters to a depth of 200 metres. The electrodes transmitted signals to receptors and data were saved to a computer. Information was analysed by specialised software.

"After analysing, interpreting and predicting the existence of a layer of fresh water under the sea, we drilled a borehole to pump and obtain water samples for confirmation" said Bang.

Dr Tran Binh Trong, an expert from the Department of Science and Technology at the Ministry of Natural Resources and Environment, said that in the past, while carrying out natural resource exploration projects, scientists had to drill lots of boreholes, which damaged the geological environment. Thanks to the 2D electrical imaging method, natural resources exploration has become less harmful to the environment.

Trong also said that with further development, the method would help investigators explore other natural resources and minerals on the sea floor./.