Encroachment, unauthorised construction and dumping of solid waste on canals and drains have been worsening the waterlogging problem in the capital.
Dhaka city has been experiencing extreme waterlogging for the last few years. Even a light rain submerges many streets and avenues in the city.
Increased urban development by grabbing the drainage system often results in waterlogging, leaving parts of urban area inundated for several days during the rainy season.
Canals and drain are being encroached in various ways like unauthorised landfilling, illegal construction over canals, expansion of slum and solid waste dumping.
Urban experts and residents are in fear of massive waterlogging in the capital in the days to come as the agencies concerned remain as indifferent to the perennial problem as ever.
The canals of Dhaka city are under serious threat of extinction and require immediate action to be freed from grabbing and encroachments, they said.
All the 35 canals of the city have been grabbed fully or partially, leaving the city drainage in a bad shape while development works under the city corporations started late this year only to add to public sufferings.
Rapid urbanisation causes extensive urban area expansion and as a result canals, wetland and other water bodies are quickly vanishing from the landscape.
Sharif Jamil, an environment activist and also the Joint Secretary of Bangladesh Poribesh Andolon (BAPA), told the Daily Sun that canals and drains are the main systems for surface runoff in the city.
“Dhaka’s waterlogging problem can not be solved without restoring the drains and canals,” he said.
More than 10 canals in Dhaka city have been filled up entirely or turned into box culverts to construct roads.
Roads were constructed in Rayerbazar, Rajabazar, Gopibagh and Shyampur Kadamtala filling up canals for making the way for stormwater and sewerage lines.
Segunbagicha canal, Dholai Khal-1, Dholai Khal-2, Debdholai Khal and Paribagh canal have been narrowed down for building box culverts.
All the covered water channel remains clogged due to lack of proper maintenance and water cannot properly pass through the channel, creating severe waterlogging after a heavy rain.
Parts of the Dholpur canal were filled up for constructing roads while the rest was turned into a box culvert.
A portion of Hazaribagh canal was filled up for a road while another portion is still open for water flow. This is the main canal of the southwestern part of the city.
Kalyanpur canal serves as the drainage system for the whole Kalyanpur area as well as Adabor, Baitul Aman Housing and parts of Shyamoli, but a big portion of the canal has been grabbed by slums.
The slum covers a wide area of the canal, having tin-shed houses, built on bamboo pillars. Even a vegetable market stands on the canal.
The canal is getting shrunk due to garbage dumping while commercial buildings have also eaten up parts of it.
Katasur canal in the city’s Mohammadpur area has dense population distribution along its banks.
A number of box culverts were built on this canal, but most of these are poorly planned, as most of the culverts are very small in size and allow a narrow passage to pass water.
Garbage dumping remains a serious problem in this canal that turned the canal dead in several points while the environment is polluted by foul odours.
Khilgaon-Basabo canal flows unauthenticated through residential areas, but a lot of garbage dumping is found here, making the canal stagnant.
Gerani canal has the catchment area across Gerani, Sabujbag, Khilgaon, Basabo, Mugdapara and these places are densely populated.
It also faces uncontrolled waste dumping and encroachment, which becomes a breeding ground for mosquitoes and foul odour.
Manda canal is situated at the south-western edge of Dhaka city, in which construction of houses and pillars is a very common scenario.
Renowned urban planner Khondoker Neaz Rahman said, “The drainage system has to be clean to ensure an uninterrupted flow of sewerage water. We also need to ensure the water the reseeding points, especially rivers surrounding the city are clean and open.”
The drainage system of Dhaka city consists of 43 major canals, which used to drain out the wastewater (domestic and sewerage) to the surrounding rivers.
Heavy encroachment in the outskirt canals is causing the inevitable collapse of the natural drainage system, experts said.