In May last year, commuters in Dhanmondi froze in disbelief as a large hole suddenly opened in the middle of a paved road near Shankar bus stand.
The collapse grabbed widespread attention on social media, with pictures of the gaping chasm circulating across platforms. Authorities quickly attributed the incident to soil erosion. Geologists, however, warned of a deeper cause.
The Shankar bus stand incident offers a stark glimpse into a growing crisis beneath Dhaka. Frequent earthquakes in recent years have heightened concern about landslides, building collapses, and underground instability across the country. Experts now caution that the capital faces an additional, largely invisible threat: decades of excessive groundwater extraction have weakened the city’s subsurface structure.
Professor at Dhaka University’s Department of Geology, Sanzida Murshed, describes the situation as a “silent accumulation of deepening risk.” She explained that declining groundwater levels create hollow spaces underground and reduce soil bearing capacity, raising the likelihood of subsidence or land sinking.
A study published in the journal MDPI titled “Assessment of Groundwater Level Decline and Identification of Adaptation Strategies for Sustainable Water Supply in Dhaka City” shows that groundwater levels in different parts of Dhaka are falling by about 0.6 to 2.4 metres per year.
Researchers warn that the decline could reach 2–3 metres or even more in the future. A few decades ago, water could be found at depths of 10–20 metres. Today, in many areas, drilling must reach over 70 metres to access groundwater.
According to Dhaka WASA, dependency on groundwater for Dhaka water supply is very high, with 78–80 percent of water still coming from underground sources. The organisation says this reliance continues to accelerate the decline of the groundwater table.
Environmental scientist and Executive Director of the Bangladesh Centre for Advanced Studies (BCAS), Atiq Rahman, described the situation as a sign of severe ecological stress.
He explained, “Groundwater forms a slow-moving ecosystem. Monsoon rains gradually recharge it, while extraction persists year-round. Excessive pumping creates voids underground that draw water from neighbouring aquifers, gradually destabilising the entire system.
“Unregulated irrigation, continuous tube-well operation, uncontrolled deep boreholes, and Dhaka’s concrete-covered surface worsen the problem by preventing natural rainwater recharge,” he added.
According to the environmental scientist, evidence already shows noticeable subsidence in several parts of Dhaka over the past two decades. Mirpur has sunk nearly 10 inches, Uttara about nine inches, and the Ramna and Cantonment areas around eight inches. Experts say these shifts may lead to systematic subsidence and indirectly magnify earthquake damage.
Citing Dhaka WASA’s data, President of the Bangladesh Institute of Planners Adil Mohammed Khan said, “We are still extracting a huge amount of Dhaka’s water from underground, which is not sustainable in the long term. As water levels continue to drop, many areas of the city are already experiencing land subsidence.”
Highlighting the lack of alternative sources, Adil, also head of the Department of Urban & Regional Planning at Jahangirnagar University, pointed out, “The rivers surrounding Dhaka are so polluted that they cannot be used directly.”
As a result, projects to bring water from the Padma and Meghna rivers or supply from waterbodies in Savar’s Bhakurta Union can be essential measures to reduce pressure on groundwater, he explained.
The imbalance between groundwater recharge and extraction is making the situation even more complex. Satellite observations using InSAR and GRACE data from 2014 to 2023 show that Dhaka receives roughly 300–350 million cubic metres of groundwater recharge annually. Extraction, however, reaches nearly double that amount: 600–700 million cubic metres or more. This persistent gap creates a permanent deficit, leading to continuous drawdown.
As aquifers dry, upper soil layers weaken. Areas with rapid groundwater decline also show greater surface subsidence, collectively threatening the long-term stability of buildings, roads and infrastructure.
Explaining the direct impact of groundwater decline, Adil said, “These voids can cause road collapse or land subsidence. They also pose an indirect link to earthquake risk. Changes in soil density and stability may amplify earthquake damage, even though they do not directly trigger quakes.”
Professor Sanzida Murshed rejected the misconception that deep water extraction itself causes earthquakes. According to her, scientific evidence shows otherwise. But excessive extraction weakens subsurface materials, which may intensify damage if an earthquake occurs for other reasons.
Experts emphasise that sustainable solutions require comprehensive and long-term measures rather than isolated efforts. According to Sanzida, the key to sustainable solutions lies in rational or consumptive use – where groundwater is used for drinking water, but surface water is used for irrigation, industry, and many household purposes. This requires treatment plants, sustainable water-treatment facilities, and major changes in awareness.
Atiq Rahman stressed the need for reforms across education, policy, infrastructure, and implementation. He said authorities must introduce water education in schools, return to using surface water in cities, and restore canals, wetlands, and rivers to reopen natural recharge pathways.
As the city continues to sink quietly beneath its feet, experts warn that without urgent, sustained action, Dhaka risks a future where every heavy rain, every tremor, and every poorly planned borehole could trigger another collapse; revealing just how precarious the city’s hidden foundations have become.
