Experts at a seminar here on Sunday stressed preparing a water budget for the country's coastal region to meet its future freshwater demand as salinity is on the rise in coastal aquifers, destroying freshwater sources.
They said the water budget should be announced keeping a balance between the demand and reserve of freshwater, and water must be extracted from underground by measuring how much water is withdrawn and how much gets recharged to aquifer each year.
A water budget reflects the relationship between input and output of water through a region. Thus, it has a direct comparison of supply of water and the natural demand for water.
Bangladesh Climate Change Trust (BCCT), Bangladesh Water Development Board (BWDB) and the Institute of Water Modelling (IWM) jointly organised the seminar on the project titled 'Establishment of Monitoring Network and Mathematical Model Study to Assess Salinity Intrusion in Groundwater in the Coastal Area of Bangladesh due to Climate Change' at Ban Bhaban in the capital.
Making a power-point presentation, BWDB groundwater hydrologist Dr Anwar Zahid said scarcity of drinking water is already visible in the country's coastal region and the situation will be severe by 2050 in climate change scenario.
The authorities concerned should immediately prepare a water budget and water allocation plan to address the growing water challenges because salinity is gradually destroying freshwater sources in the area, he added.
Pumping in the coastal zone, even without climate change, is an important determination of salinisation rate, Dr Zahid said.
Citing the study findings, he said the water budget study reveals that the river plays an important role in balancing its inflow and outflow, which means there is an interconnection between river and aquifer.
IWM senior specialist Goutam Chandra Mridha said freshwater aquifers in all coastal districts will be contaminated by salinity by 2050, intensifying freshwater crisis there.
Salinity will reach some 65 kilometers up on the river water from the coastal belt, he predicted.
IWM executive director Prof Dr M Monowar Hossain said there is no doubt that the causal region will face scarcity of drinking water as the coastal aquifer is shrinking gradually.
He said many countries are using modern technology to recharge groundwater and Bangladesh should use that to do so.
According to a new study carried by the Department of Public Health Engineering (DPHE) and IWM the severe salinity zone in the country will increase by 14 percent by 2050, accelerating the freshwater crisis in the region.
The study was carried out over a 1,534-sqm area in parts of Khulna, Jessore and Satkhira during 2010-2014 to assess the extent of salinity and intrusion, and aquifer vulnerability in the area.
State Minister for Water Resources Muhammad Nazrul Islam, Water Resources secretary Dr Zafar Ahmed Khan and IWM deputy executive director Dr AFM Afzal Hossain, among others, spoke at the seminar.    ?UNB