Photo : TDM
Dhaka is now facing an imminent threat of severe flooding due to the alarming loss of waterbodies, wetlands, and vital reservoirs. Although the capital city was once renowned for its unique natural drainage system, the environmentalists and urban planners raised concerns about the city's vulnerability to floods and the growing risk to its population.
The experts are of the opinion that rapid urbanisation has taken a toll on Dhaka's natural drainage system over the past few decades.
Reservoirs, ponds, and canals have been filled in, and wetlands have been encroached upon by housing developers. As a result, the capital city is now at a critical juncture, where the potential for devastating floods has risen substantially.
According to recent estimates, over the next decade, more than two crore people, constituting 12 percent of the country's population, could be at risk of new floods. This escalating danger is primarily attributed to the expanding settlements and infrastructure along floodplains and riverbanks, exacerbated by the looming impacts of climate change.
Urban planners emphasise that, ideally, 12–15 percent of Dhaka's area should comprise water bodies to ensure effective drainage. However, the current reality falls woefully short, with only 5 percent of the city's land dedicated to water bodies. A disconcerting trend reveals that more than 60 percent of Dhaka's wetlands have been lost within the last three decades, as documented until 2016.
A survey spanning from 2003 to 2011 highlights the distressing fact that 65 ponds within the undivided Dhaka city were identified. Regrettably, many of these ponds have been obliterated by urban development, leaving irreparable voids in the city's natural drainage system.
Recently, the government organisation BADC started construction of laboratory by filling about 12 acres of low land in Kalyanpur. The low-lying land important for drainage of Dhaka is shown as reservoir in DAP. The reservoir on the west side of the road from Kakali to Banani railway crossing in Banani, the reservoir between the airport road and the railway line from Kuril Bishwa Road to the airport, has been filled for the purpose of the elevated expressway.
Besides, the reservoir has also been filled during the construction of the Kuril flyover. However, a lake is kept there. A site office of the Purbachal project has been made by filling the low-lying land between Kuril Bishwaroad-Joarsahara. Uttara’s Sector 18 area was also once a vast reservoir. Khilkhet Police Officers Housing, Asian City, Bashundhara Residential Area, and a 300-foot road have also been filled in the swamp.
Dhaka North City Corporation’s Amin Bazar Landfill, Madhumati Model Town, and Aminbazar National Grid’s power substation in the same area have also been filled by swampland. Banashree, Aftabnagar, Satarkul, Basila, and surrounding areas of Mohammadpur, west of Dhaka, have also been developed by filling low lying areas.
Chairman of the Urban Research Centre, Nazrul Islam, said, "The government has various plans to keep the reservoir. But they are not able to keep themselves, and they are not able to meet the housing needs that are available at the private level. It is a failure of government institutions."
"Businessmen’s greed for profit, non-compliance with laws at the individual level, and a lack of open spaces are fatal. Apart from the government, prominent citizens can also be blamed for this, they don’t talk much about the issue," he added.
Experts said that the capital will sink if the rainfall and river water rise.
The Meteorological Department has warned of the possibility of flash floods in advance. Along with this, heavy rainfall has also been reported this month. Even if it rains for some time, water accumulates in different parts of the capital.
In this situation, if it rains for a few days in a row, besides the waterlogging, the water of the nearby rivers will enter the capital, and the experts fear that it will be flooded.
According to a report by NASA’s Earth Observatory last year, the population of Dhaka was 57 lakh in 1988. But in 2022, it increased to 2 crore. Due to this massive increase in population,
Dhaka is now one of the most densely populated cities in the world. Due to this,many people here have to live in flood-prone areas.
On the other hand, an analysis in Nature magazine said that Dhaka is surrounded by rivers. Buriganga in the south, Turag in the west, Tongi Canal in the north, and the Balu River in the east Since 2000, the population on the banks of the Buriganga and Balu rivers has increased. The capital is at serious risk of flooding this year as the surrounding rivers are not dredged and the inner canals are unencumbered and rehabilitated. At the same time, the dilapidated condition of the flood control dams around Dhaka has increased the level of risk.
Water expert Prof. Ainun Nishat said, "The water flow channels of major rivers across the country, including Dhaka, have been filled day by day due to a lack of renovation. This is the situation today because no government has taken the initiative to mine the rivers."
He also said, "The Burganga, Turag, and Shitalaksha rivers increase in flow due to heavy rainfall during the monsoon. If the flood control dams are not repaired, the surrounding areas, including Dhaka, will be submerged in major floods."
Dhaka has western and eastern city protection dams for flood control. However, most of the land acquired for the construction of the dam is still vacant. Again, due to a lack of repairs, the dam collapsed at several points. As a result, this dam is at risk.
On the other hand, the eastern part of the capital is completely unprotected. Although the ‘Dhaka East Flood Control Dam and Bypass’ project has been taken up, it is not being implemented. In this situation, urban planners are afraid that if the waters of Buriganga, Turag, Balu, and Shitalaksha rise, the capital city of Dhaka can easily get flooded at any time.
Sources at the Water Development Board said that the capital, Dhaka, was affected by the flood in 1988. After that, the government took the initiative to build a flood control Dam in Dhaka district. In that initiative, a dam was constructed from behind Mitford Hospital to Tongi Bridge through Nawabganj, Hazaribagh, Gabtali, and Mirpur in the western part of Dhaka.
As a result, in 1998, 2004, and 2007, there were floods in different parts of the country, but the flood water could not enter the capital, Dhaka. However, due to a lack of renovation, the dam has collapsed at several points along the 14-kilometre stretch. The whole dam has become very weak.
Not only because of the flood control Dam, but because the canals that used to get water out of Dhaka City are non-existent today. The few canals that do exist are dying from encroachment and pollution. The drainage system in Dhaka is also in bad condition. Drainage renovations are going on across the capital. But there is no benefit in reforming them. Due to the indiscriminate use of polythene, which is a major pollutant, the drainage system breaks down within a few days. Capital roads are flooded with little rain.
As many canals in Dhaka have become polluted due to encroachment, the rivers around them are now almost dead. Buriganga, Turag, and Shitalaksha are lifeless. They are non-flowing in possession pollution. Apart from this, Balundi is now almost dead as a result of the encroachment. Dhaka’s water flows through all these rivers. Due to the lack of flow in these rivers, the water in the capital cannot come out easily.
The Dhaka district administration has identified 58 canals in the Dhaka metropolitan area. Of these, 37 canals have been occupied by the Capital Development Authority (RAJUK), three government and seven private institutions, political parties, and 248 individuals. As a result, the flow of the canals is no longer normal.
In this regard, urban planner and architect Iqbal Habib said that in the last two decades, most of the reservoirs in Dhaka city have been filled and multi-story buildings have been constructed. Many reservoirs have been filled by individuals and private institutions as well as by the government. As a result, when water accumulates in the capital, there is no place for it to escape easily.
"Besides, the wetlands around Dhaka have also been taken over by various housing companies. Most of the wetlands in Savar, Ashulia, Keraniganj, and Purbachal have been filled. There is no proper arrangement for water drainage in these areas. Housing is being developed in these areas completely unplanned. As a result, if the water in Dhaka’s rivers rises, it will enter all the surrounding areas, including the capital," he added.
It is noted that Dhaka was submerged in the flood of 1988. More than two thousand people died during that time, and about 900 people died in the 1998 flood. It caused a loss of about 350 crore US dollars.
TDM/SD
