Can Dhaka Ever Become a Sponge City?

The monsoon may be retreating, but Dhaka’s waterlogging problem is not. Every year, a few hours of heavy rainfall are enough to bring parts of the capital to a standstill. Roads disappear beneath floodwater, traffic grinds to a halt, businesses struggle to operate, and commuters spend hours trapped in congestion. Decades of unplanned urbanisation, disappearing wetlands, encroached canals, and inadequate drainage have left the city increasingly vulnerable to it.

The challenge, therefore, is not simply the amount of rain Dhaka receives, but how poorly the city is equipped to absorb, store, and manage it. Around the world, a growing number of cities are embracing a different philosophy known as the “Sponge City” approach. Instead of treating rainwater as waste that must be drained away as quickly as possible, Sponge Cities are designed to absorb, store, filter, and gradually release rainwater through natural and engineered solutions. The concept recognises that cities should function more like ecosystems than concrete landscapes.

China has become the global pioneer of this idea. China began its national Sponge City initiative in 2014 and selected 30 pilot cities in two batches in 2015 and 2016, investing billions of dollars to transform urban infrastructure. Cities such as Wuhan, Shenzhen, Shanghai, and Xiamen introduced permeable pavements, rain gardens, green roofs, wetlands, restored lakes, and underground water storage systems. According to China's Ministry of Housing and Urban-Rural Development, the long-term goal is for cities to retain and reuse at least 70 per cent of rainwater through natural infiltration and storage measures. Research and evaluations of Sponge City projects suggest that green-blue infrastructure can reduce peak stormwater runoff, improve water quality and groundwater recharge, and provide wider environmental benefits such as cooler urban environments and improved biodiversity.

China’s experience also shows that Sponge Cities are not a magic solution. Many pilot cities became better equipped to manage low- and moderate-intensity rainfall, but extreme storms could still overwhelm their systems. The lesson is clear: nature-based solutions work best when combined with effective drainage systems, accurate weather forecasting, and sound urban planning.

For Dhaka, these international experiences carry important lessons. The capital was once surrounded by rivers, canals, floodplains, and wetlands that naturally absorbed excess rainwater. Over the past several decades, many of these natural drainage channels have been filled for roads, housing, and commercial developments. According to environmental experts and studies by the Institute of Water Modelling (IWM) and the Bangladesh Institute of Planners (BIP), the loss of wetlands has significantly reduced the city's capacity to manage stormwater naturally.

The consequences extend beyond waterlogging. Dhaka’s disappearing wetlands and open spaces have also reduced the natural pathways through which rainwater can seep into the ground and replenish groundwater. The city depends heavily on groundwater for drinking water, even as groundwater levels continue to decline. Allowing more rainwater to infiltrate the soil rather than rapidly flushing it into drains could therefore serve two purposes at once: reducing surface waterlogging while helping replenish underground water reserves.
Dhaka can embrace the Sponge City approach, but it will need a model tailored to its own realities rather than a copy of China’s experience. Bangladesh’s financial, institutional, and governance realities differ considerably from those of China. Besides, large-scale infrastructure projects require significant investment and long-term political commitment. So, Dhaka needs a locally adapted Sponge City strategy that combines affordable green infrastructure with stronger urban governance.

Simple interventions can produce meaningful results. Parks can be redesigned to temporarily store stormwater during heavy rainfall. New buildings can be required to install rainwater harvesting systems and green roofs. Sidewalks and parking areas can use permeable paving materials instead of fully sealed concrete. Existing canals and wetlands should be restored rather than encroached upon. Urban forests and roadside vegetation can increase water absorption while simultaneously reducing urban heat.

Moreover, no Sponge City strategy can succeed if natural retention areas continue to disappear under illegal development. Protecting rivers, canals, and floodplains must become a national climate adaptation priority rather than merely an environmental concern. Citizens can support drainage resilience by reducing waste dumping and maintaining neighbourhood green spaces, but these efforts cannot substitute for effective enforcement, infrastructure maintenance, and protection of wetlands and waterways.

Encouragingly, Bangladesh has already taken small steps toward climate adaptation. Projects involving canal restoration, urban greening, and water-sensitive planning are emerging in different cities. Yet these initiatives often remain fragmented. What is missing is a comprehensive vision that integrates flood management, climate resilience, biodiversity, and urban development into a single planning framework.

The Sponge City concept offers precisely that integrated perspective. As sea levels rise, rainfall patterns shift, and cities continue expanding, Bangladesh can no longer rely exclusively on larger drains and higher embankments. Sustainable cities must learn to work with water rather than constantly fight against it. With the right planning, investment and political will, Dhaka can move towards a future where rain is no longer synonymous with disruption, but becomes something the city is designed to accommodate. 
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The writer is a journalist