Dhaka has a complicated relationship with rain.
Every monsoon season, the city braces itself. Roads disappear beneath the grey sheets of water, traffic thickens into something barely moving, and the entire neighbourhood holds their breath through hours of downpour. People wade through knee-deep streets on their way to work, cursing the sky.
And then, months later, when the heat settles in and the earth dries hard, the city panics about something different entirely. They get worried that the water beneath their feet is disappearing. But, in reality, they are just two sides of the same story.
I am reminded of this contradiction almost every day during the monsoon season. My everyday home to work commute from Dhaka to Gazipur has not only taught me patience, but has also taught me to watch water from another perspective.
What I have seen is that, during the rainy season, it takes surprisingly little rainfall for parts of Dhaka and Gazipur to become waterlogged and traffic to decelerate dramatically. Watching rainwater accumulate on roads and drains, I often find myself pondering upon a simple question: If water is everywhere around us, why are we struggling to replenish the water below us?
Bangladesh is considered one of the largest extractors of groundwater in the world. Studies have shown a declining groundwater level of 2-3 metres every year, across the Dhaka city. According to the annual report of Dhaka Water and Sewerage Authority (WASA) from 2023-24, it draws around 67% of the city's water supply from underground sources.
This poses a severe environmental threat as it causes a significant decline in the water table. Hydrologists who have modelled the trend warn that, on current course, Dhaka's water table could fall to roughly 100-120 metres by mid-century, deep enough to make pumping extortionately expensive for ordinary households long before then.
Meanwhile, Dhaka receives roughly around 2,000 mm of rainfall annually, which is a generous amount but too little of that amount reaches the underground aquifers. Instead, it races across sealed surfaces, overwhelms drains, floods roads, and eventually disappears into rivers and channels, carrying with it the chance to replenish what we are steadily drawing down.
For ages, we have prioritized evacuating water as quickly as possible through drainage networks and engineered flood control structures. Though these investments are important, they are not a long-term sustainable solution and are the cause of groundwater depletion as well.
We are drowning and running dry at the same time, in the same city, often in the same week. This is the paradox that has been lying at the heart of urban Dhaka, a city which drowns in July and thirsts in March, and treats both seasons as if they have nothing to do with each other.
To understand this contradiction, we need to see how the city grew. Part of this result is caused by geology but mostly by us. Rapid urbanization and industrialization have caused the wetlands, ponds, canals, and open spaces to gradually disappear beneath roads, buildings, and other development that once absorbed and stored rainwater.
Much of the city is also covered by a clay layer that limits the natural infiltration of rainwater into deeper aquifers and increases surface runoff.
Rainfall that could help replenish groundwater instead accumulates on streets and neighbourhoods resulting in urban flooding, fresh water scarcity, and environmental degradation.
Other cities have begun to look at it differently. After Hurricane Ida battered New York in 2021, the city accelerated investments in green infrastructure designed to manage rain where it falls. It expanded the use of rain gardens, bioswales, permeable pavements, and stormwater retention systems rather than relying solely on larger drainage infrastructure.
As of today, New York has invested more than one billion dollars in over 11,000 green infrastructure installations. The city is learning to slow the rain down, to let the city absorb what it once only deflected.
Rain gardens can be planted within just a few square metres and are suitable for the space within school grounds, in mosque courtyards, on road space, in parks, and market areas. These interventions can have a significant impact on the management of rainwater in a city.
Bangladesh need not to replicate New York exactly but the lesson is relevant. More importantly, we already have local evidence that such ideas can work.
Researchers at the Department of Geology, University of Dhaka have successfully carried out pilot projects at Shahidullah Hall compound, University of Dhaka, using trench-and-borehole systems to address waterlogging while enhancing groundwater recharge.
Instead of allowing rainwater to remain trapped on the surface, these systems help flow water into permeable underground layers where it can be stored naturally.
The results are proof that relatively simple interventions can simultaneously reduce flooding and also contribute to replenishing groundwater resources.
Even Dhaka WASA has stated a goal to reduce the dependence on groundwater and increase the use of alternative water sources. Alongside large-scale water supply projects, there is also a need to capture more of the rain that already falls on the city.
Also, it has great economic externalities. Waterlogging costs the city every year in lost working hours, damaged goods, disrupted transport, and public health burdens that fall hardest on those least able to absorb them.
If we measured them properly, investments in groundwater recharge and stormwater capture might look far less like expenses and far more like long-term savings.
And climate change makes the urgency unavoidable. In the near future, South Asia is expected to see more intense and less predictable rainfall. The city that only knows how to drain will struggle more with every passing decade.
Therefore, the question is not simply how quickly we can remove rainwater from our streets but how effectively we can store it for the future.
The rain is not our enemy. Wasting it is.
Syeda Shagin Akhter is a Lecturer in Economics at Bangladesh Open University.
