Why waterlogging in Dhaka city

Despite repeated plans and projects undertaken by the governments over the past decades, severe waterlogging still wreak havoc on the life of Dhaka city dwellers. Only an hour-long rainfall inundates most parts of the city and the city transportation comes to a stand still. As shown in the above pictures, flawed implementation process of the projects itself is a major reason behind the waterlogging. The on-duty engineers, technicians and workers are found less bothered about ensuring smooth and free-flow of water and sewage through the mega pipes.

Thus, the multi-million-dollar projects taken up aiming at alleviating the city’s waterlogging menace in reality exacerbate the perennial problem. The ambitious projects funded by development partners like World Bank, IDA and JICA have done little to improve the situation. Authorities concerned have repeatedly excavated city roads in the name of installing giant sewerage pipelines underground, and yet there has been virtually no improvement.

Experts say that due to a lack of comprehensive planning, coordination among the government authorities and lastly ignorance are said to be the main reasons for which the city is inundated every time it rains abundantly. The effects of water logging on city life is enormous. It causes adverse social, physical, economic and environmental impacts. Flooding on the streets causes unprecedented disruption of traffic movement, often for hours while it also causes colossal damages to infrastructure.

The impact from loss of potential income opportunities encountered from virtual shutdown of businesses due to the inundation cannot be simply measured in numbers. The loss is often immense which is considered a huge damage on the city economy. With each intense rainfall that pounds the city, lives of the city inhabitants, especially those living in the low lying areas, are severely interrupted. In the recent past, rapid urban developments and even worse the gradual landfill of low lying areas around the city, rivers and canals has further worsened the problem.

Town planners say that the city plunges into a nightmare of public despair every time it experiences normal monsoon shower that instantly floods the city roads which literally brings everything to a standstill. Dhaka Water Supply & Sewerage Authority (DWASA) with 370km storm drainage pipelines of 750mm to 1,830mm diameter, covers only one-fifth of its 400sqkm service area. Under the city corporations a total of 2000 km of sewerage pipelines are now functioning.

Experts said that rainfall more than 40mm at a time floods the city which takes at least three to five hours to recede. The available pumping facility can drain out up to 20mm rain, according to Wasa. According to the Flood Action Plan and DAP, the city should have conserved 5,523 acres of water retention area which is only 1.57 percent of the 1,528sqkm of Dhaka's master plan. The city also has 20,093 acres of canals and rivers (5.7 percent) and 74,598 acres (21 percent) of flood flow zones.

Rain water is supposed to be carried away instantly to low-lying retention areas by a well-networked storm drainage system. But with the network destroyed and the artificial pipelines clogged with solid wastes, it takes hours for rainwater to pass. Experts said that the city needs an efficient drainage network, unobstructed canals and free flood zones around it to save it from the perennial waterlogging.

According to a 2015 study by University of Dhaka, a total of 24 points have been identified where serious waterlogging occurs. The points where waterlogging is common are identified as, Dhanmondi, Hajaribagh, Shankar, Jigatola, Rayer Bazar, Mohammadpur, Shyamoli, Sher-e-Bangla Nagar, Darus Salam, Mirpur, Pallabi, Cantonment and Uttara.

Mustafizur Rahman, Chief Executive Officer of Dhaka South City Corporation (DSCC) told Bangladesh Post, “To address the logging problem of Motijheel, Secretariat, Kakrail to Gonobhaban, a massive sewerage construction work is continuing. We hope this would substantially reduce the current waterlogging crisis in the city.” he added.

“The sewerage pipe that we are installing are much bigger in diameter comparing to previous ones. So, it would carry more rainwater and hence flush out greater volumes of water out of the city streets,” he said. The government recently launched a Tk 550 crore project to remove the water logging problem at 13 points of Dhaka city. As part of the effort, Dhaka Wasa took up the project titled ‘Expansion of Drainage Network and Developing Canals of Dhaka City’ last year, which was approved by the executive committee of the national economic council (ECNEC).

With the initiative, some 52 lakh city dwellers will be relieved of waterlogging problem. The project will also help ensure smooth movement of traffic and pedestrians during heavy rainfall. Dhaka WASA will implement the project by December 2020.