Research shows death of groundwater; suggests stopping irrigation right away
Except for some pockets, all the groundwater aquifers down to 600-700 feet below in 140 upazilas of 19 coastal districts have become saline due to seawater intrusion, a government research has found. More alarmingly, the groundwater in some areas of 16 of these districts is contaminated with arsenic. In Gopalganj and Pirojpur and in Patharghata upazila of Barguna, there is no fresh water down to 1,100 feet below, according to experts involved with the research.
The coastal region is home to about 2 crore people and some of them are sometimes compelled to drink such water, especially in the dry season when surface water is not available.
Experts say intrusion of seawater is taking place because of climate change and the situation is worsening through heavy lifting of groundwater.
They suggest preserving the available fresh water in the aquifer system in these districts only for drinking purposes.
Anwar Zahid, deputy director of the groundwater hydrology department of Bangladesh Water Development Board, presented the findings of the study at a workshop at Biam auditorium in the capital yesterday.
Titled “Establishment of Monitoring Network and Mathematical Model Study to Assess Salinity Intrusion in Groundwater in Coastal Area of Bangladesh due to Climate Change,” the research was financed by the government’s Climate Change Trust Fund.
“People from that region were already suffering owing to a lack of drinking water. So we conducted this research to find out the availability of drinkable fresh water,” Anwar, who led the research, told The Daily Star after the programme.
In most of these areas, the shallow aquifers (50-70 feet deep) were comparatively less saline due to groundwater recharging, he said, adding that people of many areas were drinking such saline water.
In Satkhira, for example, no aquifer layer beyond 300 feet was found. “All are clay and silt clay beyond 300 feet in Satkhira.”
Asked why Gopalganj and Pirojpur have saline water, he said the seawater that inundated the coastal areas due to a rise in sea level 10,000 to 12,000 years ago remained still entrapped there.
“But it needs extensive research before one can reach this conclusion,” he added.
Speaking as the chief guest, Sheikh Altaf Ali, senior secretary of the water resources ministry, said the coastal belt was most vulnerable to climate change and it was unwise to use fresh water for irrigation without preserving drinking water.
M Azizul Haque, director general of the Bangladesh Water Development Board, who presided over the session, said about 80 percent of irrigation water now came from underground sources.
Prof Monowar Hossain, executive director of the Institute of Water Modeling, and Shawkat Alam Khan, the project director, also spoke on the occasion.
Prof Monowar said the southern region faced a crisis of fresh water as the country depended on the water of its trans-boundary rivers, which lacked water flow during winter.
The researchers tested groundwater from all the 140 upazilas of the 19 districts — Bagerhat, Barguna, Barisal, Bhola, Chandpur, Chittagong, Cox’s Bazar, Feni, Gopalganj, Jessore, Jhalakathi, Khulna, Laxmipur, Narail, Noakhali, Pirojpur, Patuakhali, Satkhira and Shariatpur.
To identify fresh water zones in the coastal region, they tested groundwater aquifers down to 350 meters below, with 1,100 samples being taken at different times.
-With The Daily Star input
