Aquifer level fall invites salinity into freshwater, say experts
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12/03/2012
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Daily Star (Bangladesh)
Rapid decline in aquifer level has exposed parts of the southwestern region to huge saline water intrusion into ground, surface waters and soil to affect crops and ecology, say experts.
“Saline water is penetrating further into the mainland of southwestern region to affect the only remaining freshwater pocket of the Tentulia River and the Meghna estuary”, Dr M Eftekharul Alam, expert, Bangladesh Agricultural Development Corporation (BADC), told the news agency.
A recent study of BADC has found that huge saline water is likely to penetrate about 40km inland due to excessive withdrawal of groundwater, he said.
Unplanned shrimp cultivation requiring saline waters deteriorated the environment in the region while sea-level rise, being caused by climate change, could intensify salinity problem in the southwestern coastlines, he added.
Salinity intrusion is increasing gradually in the coastal belt due to different human-induced and natural causes, threatening crop production and making far-reaching adverse impacts on ecology.
Alam, an engineer of agriculture, water, and environment of state-run BADC, said water table in Salikha upazila of Magura had already gone down below the mean sea-level as the upazila is connected with the Bay of Bengal through Jessore, Satkhira, Khulna and Bagerhat.
Water flow in the rivers of the southern region has decreased sharply in the last several years, which contributed to salinity intrusion, said Umme Kulsum Navera, professor, water resources engineering department, Bangladesh University of Engineering and Technology (Buet).
“Many countries, including Australia, have stopped the use of groundwater for irrigation...We too should reduce dependency on groundwater”, Prof Navera said.
The practice causes rapid fall in groundwater table and poses serious threats to the ecosystem and biodiversity of the southern part in particular because of the region's proximity to the sea. A prospective sea-level rise has deepened the fear.
A direct consequence of sea-level rise would be the intrusion of salinity with tide through rivers, and it would be more acute in dry season, especially when freshwater flows from rivers dwindle, Dr Alam said