Dhaka is one of the fastest growing Megacities of the World with a growth rate of 4.4% per year. Urbanization in Dhaka has been rapid and demand driven with little care given to the inevitable environmental and public health consequences of unplanned, unauthorized, and unregulated development.
Although these is a storm drainage network of around 261 sq. km around the City, historically, the major part of Dhaka’s drainage system is natural consisting of canals, rivers and lakes that help reroute extra water out of the City. These water bodies act as natural flood plain, storm sewers, water retention areas, and as surface water bodies to check flood flows and allow water to percolate to the ground. Storm runoff from surrounding areas is stored in these lowland areas and the accumulated run off drained through the canals. Until only three decades ago, Dhaka had over 50 canals and lakes and was surrounded by four rivers and wetlands. Over the years, however, the Capital and largest City of the country has lost almost all of its natural drainage system and of the 50 canals that were flowing until 80s now have meagre flows in only 20, thanks to unabated encroachments from both public and private sources.
The two main reasons behind the disappearing canals are the creep of construction and the dumping of massive quantities of garbage from the surrounding neighborhoods. Another 9 canals having flow of over 10km have been converted into box culverts proved ineffective for the region as they require regular maintenance and clean water.
While recent water logging in the City of Dhaka clearly points to the curse of unplanned and unregulated development, concerned authorities have long ignored the illegal encroachment upon the canals and have failed to re-excavate, demarcate and properly monitor their condition. Due to such monumental failures of the authorities to regulate development and protect the water bodies, some areas of the Dhaka City now experience water logging even with regular rainfalls.
Experts have unambiguously stated that the loss of wetlands including canals within and around Dhaka City and the resultant collapse of the natural drainage system is causing the crippling and ever deteriorating water logging in the City. A 2015 World Bank report predicted that the potential damage from water logging for Dhaka between 2014 and 2050 would be Taka 11,000 crore. The report further stated that when more intense rainfalls as a result of climate change are taken into account, the loss would be Taka 13,900 crore between 2014 and 2050.The Dhaka Water Supply and Sewerage Authority (DWASA) has estimated that in September, 2010, water logging caused a loss of Taka 632 billion for the garment industry alone. The curse of such waterlogging affects most the poorest who, due to absence of alternate shelter, remain marooned and deal with unbearable miseries.
A Writ Petition (16898/2017) has been filed by Bangladesh Environmental Lawyers Association (BELA) before the Supreme Court of Bangladesh seeking restoration of the 50 canals of Dhaka by demarcating the same as per their original flows, removing all encroachments and structures including box culverts from the canals, and protecting them under a time bound action plan.