Princh Mondal olif, Bagerhat Correspondent

Scientists have discovered two large underground freshwater reserves beneath the Sundarbans and nearby coastal areas of Bangladesh, offering new hope for millions of people facing a severe shortage of safe drinking water.

The discovery was revealed in a recent study published in the journal Nature Communications. The research was conducted jointly by scientists from Columbia University, the University of Dhaka, and the New Mexico Institute of Mining and Technology.

For many years, people living in the coastal districts of Khulna, Bagerhat, and Satkhira have struggled with increasing salinity caused by climate change, sea-level rise, and reduced freshwater flow. As a result, many shallow tube wells no longer provide safe drinking water, forcing residents—especially women—to travel long distances to collect freshwater.

Researchers surveyed about 120 kilometers of land from Khulna to the Pashur River basin and collected data from 25 locations. Their findings confirmed the existence of two major freshwater-bearing layers extending across nearly 80 kilometers.

According to the study, the freshwater was stored underground thousands of years ago during the Ice Age. Rainwater and freshwater carried by the Ganges and Brahmaputra rivers became trapped in sandy layers beneath the ground and were later protected by thick clay deposits.

The first freshwater reserve extends to a depth of around 800 meters and covers about 40 kilometers. The second reserve lies beneath the central Sundarbans at depths ranging from 25 to 250 meters and stretches for another 40 kilometers.

However, experts warn that this water is an ancient resource, estimated to be between 10,000 and 25,000 years old. It is not quickly renewable and should not be used for large-scale irrigation or commercial purposes.

Professor Dr. Anwar Hossain Bhuiyan of the University of Dhaka emphasized that the reserves should be treated as a strategic water resource and carefully protected for future generations. Scientists also warned that uncontrolled deep tube-well installation could allow salty water to enter the freshwater layers, damaging the resource permanently.

Experts have called for science-based policies, strict monitoring, and further surveys in other vulnerable coastal districts, including Patuakhali, Barguna, Bhola, Noakhali, and Chattogram.

While the discovery offers a promising solution to the region’s long-term water crisis, researchers stress that careful management and conservation will be essential to ensure this valuable resource remains available for future generations.