Dhaka, the capital city of Bangladesh, is no stranger to flooding. As one of the fastest-growing megacities in the world, its rapid urban expansion has come at a cost—frequent, devastating urban floods. With every monsoon season, parts of Dhaka are submerged, causing traffic paralysis, waterborne diseases, economic disruption, and severe discomfort for millions of residents.
Understanding the causes of urban flooding in Dhaka and implementing long-term flood mitigation strategies is now more urgent than ever. This article explores why Dhaka floods so often, the human and environmental consequences, and what can be done to ensure a water-resilient future.
Understanding Urban Flooding in Dhaka
Urban flooding refers to the inundation of land or property in a built environment caused by rainwater overwhelming the drainage capacity of a city. Unlike river floods, urban floods are more localized but can be equally destructive.
In Dhaka, flooding typically occurs due to intense rainfall, poor drainage systems, blocked canals, unplanned construction, and encroachment on natural water bodies.
1. Key Causes of Urban Flooding in Dhaka
a. Rapid and Unplanned Urbanization
Dhaka’s population has surged from around 2 million in 1980 to over 23 million in 2025, making it one of the densest cities in the world. Unregulated urban growth has led to:
- Destruction of wetlands and low-lying floodplains
- Filling up of canals and water retention ponds
- Illegal real estate development on natural drainage zones
This urban sprawl has drastically reduced the city’s natural capacity to absorb rainwater.
b. Inadequate Drainage Infrastructure
Dhaka’s drainage system—designed decades ago for a much smaller population—can no longer cope with current rainfall volumes. Key issues include:
- Outdated, undersized, and clogged drains
- Lack of proper sewer-stormwater separation
- Insufficient number of pumping stations
- Encroachment on major drainage canals and rivers
For example, the Dholai Khal canal, once vital for floodwater drainage, is now choked due to garbage dumping and illegal constructions.
c. Monsoon Rainfall and Climate Change
Dhaka receives over 2000 mm of rainfall annually, most of it during the June–September monsoon. Climate change is increasing the intensity and unpredictability of rainfall, causing short bursts of torrential downpour that the city’s system can’t manage.
Additionally, sea-level rise and changing river dynamics in surrounding areas exacerbate the problem.
d. Encroachment on Wetlands and Water Bodies
According to a report by the Center for Urban Studies (CUS), Dhaka lost over 75% of its wetlands between 1978 and 2020 due to land grabbing and infrastructure projects.
Key lost water bodies include:
- Begunbari Khal
- Gulshan-Baridhara Lake (partially restored)
- Rampura Canal
These natural features previously served as flood buffers, absorbing excess rainwater.
e. Solid Waste Mismanagement
Plastic bags, construction waste, and household garbage regularly clog drainage pipes and canals. Without proper waste segregation or disposal facilities, drains are rendered useless during heavy rains.
2. Recent Urban Flood Events in Dhaka
- July 2023: Dhaka experienced over 100 mm of rainfall in a few hours, flooding major roads like Mirpur Road, Panthapath, and Moghbazar.
- August 2022: Severe waterlogging due to only two hours of rain. Hospitals and schools were temporarily shut.
- Monsoon 2021: Uttara, Dhanmondi, and Bashundhara residential areas faced knee-deep water for over 24 hours.
These incidents demonstrate that even short rain events can cripple the city due to inadequate drainage and emergency preparedness.
3. Impacts of Urban Flooding in Dhaka
a. Economic Disruption
- Loss of work hours due to transport breakdown
- Damage to shops, markets, and inventory
- Property damage and rising insurance costs
b. Public Health Hazards
- Increased cases of diarrhea, dengue, cholera, and skin infections
- Stagnant water serves as breeding grounds for mosquitoes
- Contamination of drinking water lines with sewage
c. Transportation and Utility Failure
- Traffic jams lasting for hours
- Disrupted public transport and emergency services
- Power outages in flooded neighborhoods
d. Social and Psychological Stress
- Displacement of slum dwellers
- School closures
- Rising stress and anxiety levels due to living conditions
4. Government Response and Infrastructure Projects
a. Dhaka Integrated Flood Protection Project (DIFPP)
Launched with World Bank assistance, DIFPP includes:
- Embankments along the Balu and Turag rivers
- Water retention ponds
- Improved floodgates and drainage infrastructure
b. Drainage Master Plan (2021–2035)
Developed by Dhaka WASA and JICA, this plan focuses on:
- Rehabilitating 65 km of canals
- Installing advanced pumping stations
- Building underground storage tanks (rainwater harvesting)
c. Smart Drainage Mapping (GIS Integration)
Dhaka South City Corporation is using GIS-based mapping to identify bottlenecks and optimize stormwater flow patterns.
d. Urban Resilience Project (URP)
Implemented with the support of the World Bank, URP aims to:
- Build flood-resilient infrastructure
- Strengthen emergency response
- Integrate community-based flood risk management
5. Sustainable and Long-Term Solutions
a. Restoration of Wetlands and Canals
- Re-excavating old canals and linking them to rivers
- Reclaiming illegally occupied flood zones
- Creating new urban retention ponds
b. Green Infrastructure and Nature-Based Solutions
- Green roofs, permeable pavements, and rain gardens to absorb rainfall
- Expanding urban green spaces to reduce surface runoff
- Restoring riverside forests and vegetation buffers
c. Solid Waste Management Reform
- Ban on plastic bags and strict penalties for littering
- Community recycling programs
- Installing trash traps in stormwater drains
d. Building Code and Urban Planning Enforcement
- Ensuring new buildings have proper drainage connections
- Penalizing encroachments and illegal construction on canals
- Promoting vertical expansion instead of land-filling lowlands
e. Community Engagement and Awareness
- Flood drills and education in vulnerable communities
- Citizen science and mobile apps to report waterlogging
- Women and youth involvement in climate resilience programs
6. Role of Technology in Flood Prevention
Early Warning Systems
- Mobile alerts on flood-prone zones
- Weather apps that predict high rainfall days
IoT and Sensor Networks
- Real-time monitoring of water levels in drains and canals
- Smart water pumps that auto-activate during rainfall
Data-Driven Urban Design
- Using AI and satellite imagery to identify drainage failures
- Predictive modeling for infrastructure planning
7. International Best Practices for Dhaka to Follow
Singapore
- Utilizes underground tanks and smart rainwater collection
- Has strict zoning laws to protect drainage reserves
Tokyo
- Massive underground floodwater tunnels
- Combines drainage with community parks
Copenhagen
- Cloudburst Management Plan that includes climate-adapted roads
- Streets double as water channels during heavy rains
Dhaka can adopt a hybrid strategy, combining infrastructure upgrades with low-cost nature-based solutions and strict urban management.
Conclusion
Urban flooding in Dhaka is not just a seasonal inconvenience—it’s a growing crisis linked to poor planning, weak infrastructure, and climate change. Solving this issue requires a multi-stakeholder approach involving government bodies, urban planners, engineers, local communities, and international partners.
By restoring natural waterways, modernizing drainage, enforcing regulations, and adopting smart technologies, Dhaka can transform into a flood-resilient, livable megacity. The time to act is now—before waterlogging turns into a year-round disaster.