Whether rainy or sunny, there is no relief for the residents of Dhaka. The city submerges in the slightest of rain, while bright sunshine turns it into an urban heat island. Aside from waterlogging and heat distress, problems such as traffic jams, year-round road digging, water and gas crises, and inadequate public transport are rendering the capital almost paralysed. To build a functional city, the Detailed Area Plan (DAP 2022-35) for the capital has recommended nature-based solutions, also stating that many of Dhaka’s sufferings can be turned into comfort if the Dhaka canals covered by box culverts are reopened and waterways are restored.
Following the 1988 flood, many areas of Dhaka were submerged along with the rest of the country, subsequently driving the formulation of various plans to free the capital from floods and waterlogging. Based on plans adopted in the 1990s, Dhaka WASA and the then Dhaka City Corporation (now Dhaka South City Corporation) began constructing box culverts over major canals in the capital. The argument in favour of building box culverts was that canals are meant solely for water flow, and that purpose is served as long as water flows, which used to cover up Dhaka’s major canals. Three decades later, government observations have proven constructing box culverts to be a mistake. The latest DAP states that there is no way to keep Dhaka functioning without restoring its lost canals, natural water bodies and waterways.
Dr Muhammad Rashidul Hasan, professor in the Department of Urban and Regional Planning at Chittagong University of Engineering and Technology (CUET), commented that alongside restoring waterways, holistic planning must be implemented to improve Dhaka’s condition. He told Bonik Barta, “There are four large rivers surrounding Dhaka and over fifty canals inside the city. Constructing box culverts over several major canals has created numerous problems in the city, causing waterlogging and destroying ecological balance. Our policymakers have realised very late that canals aren’t just for water flow, but play a vital role in maintaining natural balance. So to restore Dhaka’s livability, it’s essential to remove the box culverts according to the CS map and recover the canals.”
The process of covering Dhaka’s canals began in 1990 by transforming the Dhanmondi canal into a box culvert. Historical records reveal that the canal, originating from Dhanmondi Lake, merged into the Begunbari canal — present-day Hatirjheel. It flowed through the Kathalbagan, Rajabazar and Paribagh canals (current Shahbagh). In the 1990s, a road was constructed by building a box culvert over this entire canal, which is currently known as the “Panthapath” box culvert.
The Cheonggyecheon canal, flowing through the heart of South Korea’s capital, Seoul, was excavated in the 14th century to manage the city’s drainage system and prevent waterlogging. Five hundred years later, in the 1930s of the twentieth century, large slums grew around this canal, polluting the canal due to increasing human activities. To handle the pressure of 168,000 cars daily, Seoul city authorities covered the canal in concrete in 1960. Subsequently, by 1976, a 5.5-kilometre-long, four-lane elevated expressway was constructed over it.
Within just two decades, that highway turned into a curse for Seoul, as the temperature of the surrounding areas increased alarmingly. Finally, in 2003, Seoul’s then-mayor Lee Myung-bak took an initiative to demolish that busiest overpass at a cost of approximately $281 million. Within two years, the canal was reopened by removing the highway. A green waterfront park was developed. Planned public transport and the introduction of subways reduced private cars on the road. After the canal was reopened, the temperature in Seoul’s city centre dropped by 3.6 to 5 degrees Celsius. Various species of birds, fish and plants returned to the heart of Seoul.
In the Dutch city of Utrecht, a major canal was filled in during the 1970s to construct a massive 12-lane highway. In 2020, that highway was demolished to reopen the ancient Catharijnesingel canal.
Three hundred years ago, canals excavated in Bangkok, the capital of the Southeast Asian country Thailand, are still active. Alongside maintaining ecological balance and draining water, the canals remain busy with the citizens’ regular commutes. Experts even suggest that in the distant future, if sea and river water levels rise due to climate change, these canals will give Bangkok a new lease on life.
In 1610, Islam Khan, the Subahdar of Bengal, excavated Dholaikhal, originating from the Balu River and merging into the Buriganga, to facilitate Dhaka’s security and water communication. For several centuries, it served as Old Dhaka’s heart and primary waterway. From the 1990s onward in various periods, the Dhaka City Corporation filled in roughly three-kilometre-long Dholaikhal-1 and Dholaikhal-2, constructed box culverts, and built roads and markets over them.
Another major canal of Dhaka was the Segunbagicha Canal. Flowing from the water bodies around Ramna and Matsya Bhaban (Ramna Lake and the then marshland), the approximately 2.8-kilometre-long Segunbagicha Canal ran through Bijoynagar, Arambagh, Fakirapool and Kamalapur, passing behind Bangladesh Bank. In 2000, WASA constructed a box culvert over this canal with funding from the Asian Development Bank (ADB). RAJUK subsequently built a road over it.
Despite transforming three major canals into box culverts, Dhaka’s waterlogging problem remained unresolved. Rather, due to a lack of drainage system expansion coordinated with various mega-infrastructures, Dhaka’s waterlogging has taken on an even more complex form. In such a reality, the existing DAP has recommended opening up the box culverts inside Dhaka, alongside utilising them as waterways. According to DAP calculations, it is necessary to create 574 kilometres of waterways using the capital’s internal canals, with a total of 1,135 kilometres of waterways proposed for greater Dhaka.
Urban planners state that opening up at least three major box culverts in Dhaka would significantly reduce citizens’ sufferings. Dr Akter Mahmud, professor in the Department of Urban and Regional Planning (URP) at Jahangirnagar University, told Bonik Barta, “Because of canal filling, the city has become disaster-prone. When it rains, the city paralyses. When it gets slightly warm, people struggle to breathe. The box culverts must be demolished. Then, making the canals navigable will restore much of the ecological balance. This work won’t even cost a great deal; the canals can be restored for less than half the expenditure required to build a single metro rail.”
Stating that the government’s long-term expenditures would decrease if the canals are restored, he said, “Roads are dug up year after year. Rivers or canals don’t require anything of that sort; some dredging may be required. Compared to the money the government spends on maintaining box culverts, this is negligible. Above all, given how box culverts are increasing public suffering, they’ll have to be opened sooner or later.”
In July, heavy rainfall caused road cave-ins in several places across Dhaka. Among them, a major sinkhole was created on July 13 following the collapse of the main Dholaikhal road. Road cave-ins similarly occurred in Gulistan and the Jurain New Road. Experts state that this situation has arisen primarily because the box culverts have become weak. Relevant stakeholders have also reported that Dhaka’s box culverts are not being properly maintained.
On-site observations revealed that due to the continuous accumulation of garbage, polythene and sand, the box culverts’ depth has decreased to three to four feet, whereas their original depth was 10 to 12 feet.
Nur Azizur Rahman, chief engineer of the Dhaka South City Corporation (DSCC), considers the plan to open the box culverts quite challenging. He told Bonik Barta, “The DAP’s recommendation seems largely unrealistic. It doesn’t seem like there’s any scope left to open box culverts now in Segunbagicha, Motijheel or Dhanmondi due to the construction of the large buildings and hospitals there. RAJUK should first show that they can stop the filling of flood-flow areas and lowlands declared in the DAP right before their eyes. Even if we can save what’s still savable, Dhaka’s life will be preserved.”
On the other hand, RAJUK’s Chief Town Planner Md Ashraful Islam commented that while opening the box culverts is difficult, it’s implementable. He told Bonik Barta, “There’s no doubt that opening the box culverts is quite challenging, but it can be solved from an engineering standpoint. This can be done in several ways. There will be a canal underneath and a roadway using a viaduct method on top, so waterways and roads can be created simultaneously. Roads that have two lanes can use one lane as a canal and the other as a roadway. A feasibility study can be conducted on how this can be done or which path is the easiest. There are examples of this around the world. Without restoring these canals, public suffering in Dhaka can’t be reduced by even an iota.”