Bangladesh’s seasonal groundwater crisis is solvable

Vast demand for groundwater irrigation depletes drinking water wells, forcing many communities to struggle for months. Photo: TBS

Every year during the dry season, from mid-March to early May, reports of groundwater shortages emerge across Bangladesh. The crisis is particularly severe in the northwestern, north-central, and southeastern regions, where groundwater demand for irrigation peaks during Boro rice cultivation. 

As farmers pump vast amounts of groundwater for irrigation, many drinking water wells run dry, leaving communities struggling to access safe drinking water for weeks to months.
Hand-operated suction pumps — such as number 6 (hand tubewell) and Tara — along with low-capacity submersible pumps, often become inoperable when groundwater levels drop below their respective suction limits. While suction pumps are generally limited to lifting water from depths of around 7–8 metres, submersible pumps may also fail if the water table falls below their designed operational range. 

While monsoon rains generally replenish shallow aquifers, some areas, like the High Barind Tract, face persistent groundwater shortages throughout the year. Despite this being a well-documented, recurring annual issue, media coverage often treats the crisis as a new and unexpected phenomenon, overlooking the long-standing nature of the problem.

Understanding the seasonal groundwater crisis

To grasp the patterns of groundwater depletion, we can turn to data from the Bangladesh Water Development Board (BWDB), the government agency responsible for monitoring the country's water resources. BWDB operates around 1,200 monitoring stations across Bangladesh, collecting weekly groundwater level measurements through a citizen science approach. Local borehole observers record data, which is then entered into a central database—though often with delays of several months.

This valuable dataset, spanning decades (some records date back to the 1960s), has been used by researchers to analyse groundwater trends. However, this national dataset is not publicly available; researchers must pay for access. The data quality varies due to gaps in records, shifts in monitoring locations, and occasional inconsistencies. However, it remains one of the most comprehensive datasets—something many countries lack.

What does the monitoring data reveal?
Groundwater-level data from BWDB highlight significant seasonal fluctuations. Maps from 2015, for example, show stark contrasts between the dry and wet seasons. During the dry season (March–April), groundwater levels in many areas drop below eight metres due to irrigation for Boro rice cultivation, the suction limit of commonly used pumps such as the number 6 pump, making it impossible to extract drinking water. This issue is particularly evident in the Barind Tract, Dhaka, and its surrounding districts and southeastern areas such as Comilla. 
In contrast, during the wet season (July–September), groundwater levels rise across much of the country, with most areas returning within the suction limits of standard hand pumps.

However, exceptions remain in the High Barind Tract and parts of Dhaka, where groundwater levels persistently stay deep.

These seasonal fluctuations resulted from the changes in groundwater storage between recharge and discharge, which is not uniform across Bangladesh. Some regions experience seasonal drawdown of groundwater levels, while other areas face a more chronic problem, necessitating region-specific strategies for groundwater management and sustainable water access.

Groundwater: The lifeline of Bangladesh

Groundwater plays a crucial role in Bangladesh's economy and food security. It supplies 97% of drinking water and 80% of irrigation water, supporting both agriculture and industries like garment manufacturing. It also acts as a buffer against droughts and erratic monsoons, enhancing resilience to climate change. Over the past five decades, Bangladesh has achieved near self-sufficiency in food production, largely due to groundwater-fed irrigation. However, this reliance also means that mismanagement or over-abstraction could pose long-term risks to water security.

A widely recognised phenomenon known as the Bengal Water Machine — described in a 2022 Science journal paper — illustrates how the combination of favourable hydrological, climatic, and pumping conditions naturally replenishes groundwater. 

During the monsoon, excess rainfall recharges aquifers under favourable conditions, offsetting the water withdrawn for irrigation in the dry season. However, in some areas, this balance is under strain due to increasing demand and climate variability.

Sustainable solutions for seasonal groundwater crisis

Bangladesh's seasonal groundwater crisis is neither new nor isolated — it is a recurring challenge that demands proactive management. Rather than treating it as a short-term emergency, policymakers, researchers, and communities must work together to implement long-term solutions. 

Addressing Bangladesh's seasonal groundwater crisis requires a strategic, long-term approach. Detailed mapping of water levels is essential for identifying high-risk areas through groundwater monitoring, enabling policymakers to develop targeted solutions. Artificial intelligence techniques, such as machine learning, can enhance this process by generating more granular groundwater-level maps, helping to pinpoint depletion hotspots with greater accuracy. 

Furthermore, alternative water supply solutions should be implemented in areas where the dry-season groundwater levels regularly drop too low for standard hand pumps. Introducing communal deep wells or piped water systems can ensure reliable access to drinking water. 

Also, conjunctive use of surface and groundwater can help mitigate over-reliance on depleted aquifers by integrating surface water sources such as rivers and canals with groundwater for irrigation where feasible. 

Additionally, avoiding a 'one-size-fits-all' policy is essential, as unnecessary restrictions on groundwater-fed irrigation during the dry season could undermine Bangladesh's ongoing achievements in food security. Groundwater policies should be flexible and region-specific to balance water conservation with agricultural needs. For instance, in areas where the Bengal Water Machine is functioning effectively and has further potential, groundwater pumping for irrigation can continue with regular monitoring to ensure sustainability. 

Lastly, public awareness and education play a crucial role in groundwater sustainability. Communities must be informed about sustainable water use practices to safeguard groundwater resources for future generations.

Vast demand for groundwater irrigation depletes drinking water wells, forcing many communities to struggle for months. Photo: TBS

Professor Mohammad Shamsudduha teaches at the Department of Risk and Disaster Reduction, University College London, UK

Disclaimer: The views and opinions expressed in this article are those of the author and do not necessarily reflect the opinions and views of The Business Standard