Around 51% of the area within the capital city and its outskirts are highly vulnerable to multi-dimensional disasters – both natural and human-induced incidents including flood and waterlogging – thanks to unabated, unplanned urbanisation over the past years.
According to the “Regional Development Planning (RDP) Survey” of the capital, these areas are also at risk from earthquakes, depletion of ground water, loss of wetlands and water bodies, fire hazards, infrastructure collapses and other man-made hazards.
Besides these, the authorities lack knowledge about safe and risky zones because of the absence of micro-zoning and risk mapping for every aspect of disasters.
Rajdhani Unnayan Kartripakkha (Rajuk) conducted the survey last year while the final report was prepared this year for updating the RDP database. It would help to develope a planning policy framework for the Detailed Area Plan (Dap) to promote sustainable development of the capital.
The RDP covers an area of 1,528 square kilometres, which includes two Dhaka city corporations, Narayanganj and Gazipur city corporations, four municipalities and 72 union parishads in the three districts. A 90 sq-km area of Gazipur City Corporation and Dhamsona union have been proposed as extensions to the RDP area.
Lowland areas and cultivated lands with scattered settlements in and around Dhaka are highly hazardous zones – exposed to flooding and waterlogging. Extreme lowlands and areas adjacent to rivers are designated as very high hazard zones – accounting for 50.80% of the survey area.
It also found that the highly-elevated lands of the RDP area represented the least hazardous zone, which is only 10.91% of the total land.
Moderately high land within the less hazardous zone group is only 38.30% of the total land. Most of the bordering areas of Dhaka metropolitan were characterised as moderate flood-hazard zone.
Rajuk conducted the survey with Korean companies Saman Corporation and Han-A Urban Research Institute, and local DevConsultants Bangladesh Ltd and Sheltech (Pvt) Ltd. The initiative was funded by the Asian Development Bank.
The RDP is part of the City Region Development Project, which will be used to formulate a revised Structure Plan to construct a policy framework for the next 20 years (2016-2035).
The study shows that the impacts of flooding and waterlogging in and around the capital are the loss of water reservoirs, a decrease of ground water recharge area and ground water level, destruction of natural drainage systems and drainage congestion, disturbance of local ecology and biodiversity, loss of vegetation, destruction of aesthetically pleasant recreational sites and an increase of impervious surfaces.
The groundwater depletion risk is the result of the lowering of the water table reduction of water flow in streams and lakes which may cause land subsidence, deterioration of surface water quality, groundwater pollution and urban disasters.
Earthquake and building collapse risks are also major threats for Dhaka city. The RDP study mentions the earthquake dimension in different times and represents the vulnerability for unplanned buildings.
Due to faulty design, a six storey building at Shankhari Bazar of Old Dhaka collapsed in 2004 killing 11 people. It was built on a 200-year-old foundation designed for a three-storey structure; in 2005, the unstable structure of Spectrum Sweater Factory in Savar gave way, killing 64 people; in 2006, a five-storey building that housed Phoenix Garments in Tejgaon collapsed killing 21 people; in 2010, a five-storey building toppled onto three makeshift houses in Begun Bari killing 23 people; and latest, on April 24, 2013, over 1,138 people were killed in the horrific Rana Plaza collapse.
Besides building collapses, fire incidents in the industrial sector, mostly in garments, is a common issue, and so fire hazards are a constant threat for the city.
The study also shows that land use patterns in the capital and its outskirts have rapidly changed due to unplanned urbanisation coupled with the filling up of agricultural land by several thousand real estate companies.
Over a span of seven years (2006-2013), agricultural land and water bodies in and around Dhaka have reduced by 21.81% while residential areas have increased by 32.67%, according to the study.
Urban planners and environmentalists allege that Rajuk only formulates plans and policies, but it can never implement them in reality.
President of Asiatic Society of Bangladesh Prof Nazrul Islam, also chairman of Centre for Urban Studies, told the Dhaka Tribune: “Unplanned urbanisation in and around Dhaka and rapid fill-up of wetlands and water bodies and the building of faulty building without appropriate design, have been increasing the disaster risk for Dhaka.
“If such types of practices continue, the disaster risk for Dhaka will be rising day by day.”
Professor Jamilur Reza Choudhury, who headed the DAP experts team, said: “A large number of land developers continue to fill up flood-flow zones and grab agricultural land and river embankments and canals in and around Dhaka. This will lead to flooding, water logging and destruction of the ecology.”
He suggested that the government should concentrate on planned urbanisation and decentralisation to mitigate disaster risks for Dhaka.
Earlier, Sheikh Abdul Mannan, member (planning) of Rajuk, told the Dhaka Tribune that the RDP survey had been conducted to formulate the new DAP which may end by 2015.
