Freshwater, both surface and groundwater, in Bangladesh, particularly in the northern region, has been declining steadily for over 21 years. This was revealed in a new global study led by Arizona State University. The research found that Bangladesh is among 101 countries where freshwater has been decreasing for over the last two decades. Every year it is reducing by 2.5—10mm driven by climate change, unsustainable groundwater use, extreme droughts, and other factors effecting perilous impact on our water resources.
The findings send us the most alarming message yet about the impact of shrinking freshwater availability, climate change, continued overuse of groundwater on the water resources. The consequences could undermine food and water security for our vast population.
Apart from this study, the National Water Resources Council of Bangladesh (NWRC) has recently identified three regions of Bangladesh as water-stressed and highlighted growing concerns over declining groundwater levels. Experts warned that if unaddressed, the situation could push parts of the country to desertification. Professor Dr. Ainun Nishat, a lead water resources specialist said while the government has officially recognized three water-stressed zones, in reality there are at least 11 areas under severe stress. Immediate attention is needed to prevent the loss of vast areas of the country to desertification.
Excessive pumping of groundwater for agriculture and industry is creating underground vacuum. Experts warn that if tectonic imbalances occur, it may lead to land subsistence, sinking, and irreversible environmental damage. Overuse and poor planning are rapidly reducing safe water availability. Unregulated extraction for industrial and agricultural use, scanty rainfall and reduced river flows and unplanned urbanization have been identified as the villain of the piece for declining groundwater level.
As one expert said glaciers and deep groundwater are like ancient trust funds. Instead of using them sparingly during crisis such as prolonged droughts, we are depleting them without replenishment, edging towards freshwater bankruptcy. As a downstream country Bangladesh faces a regional disadvantage. Upstream extraction in India and Nepal continues to affect river flows. This imbalance worsens seasonal stress across Bangladesh. Climate change is compounding crisis in the country, as declining Himalayan meltwater inflows and sea level rise are already causing saltwater intrusion in several districts, further reducing both surface and groundwater availability. Due to over-extraction groundwater is being contaminated with salt and heavy metals. Some districts are now exposed to extremely elevated arsenic, salinity and groundwater depletion hazards. It had been observed that groundwater levels in urban areas, particularly Dhaka and the Barind Tract, have been declining permanently at an alarming rate which implies that the water level is not being recharged even after monsoon.
Dhaka WASA alone pumps about 3.3 million cubic metres of water everyday. Despite that families in Dhaka, tube wells are increasingly being unreliable forcing many of them to depend on costly water deliveries.
Farmers also struggle and use groundwater to irrigate their paddy field. As the population is increasing every tear, so is the demand for fresh water is rising too. It is, therefore, necessary to shift towards surface water and rainwater retention. Large scale rainwater harvesting has to be materialised and strict and sustainable water management must be enforced to prevent freshwater depletion.
