DHAKA : Bangladesh needs a more accurate flood forecasting
system, increased investment in disaster management and better urban planning
to minimise losses from increasingly frequent floods driven by climate change
and rapid urbanisation, experts have said.
Professor Dr. Md. Humayun Kabir, Dean of the Faculty of
Earth and Environmental Sciences at the University of Dhaka, said strengthening
the country’s flood forecasting and early warning system should be a priority
as timely forecasts can significantly reduce casualties and economic losses.
“If reliable forecasts are available in advance,
authorities can operate drainage pumps before water accumulates, emergency
services can be mobilised and people can take precautionary measures to protect
their lives and property,” he said.
He stressed that forecasting should be supported by modern
weather monitoring technology, including fully functional weather radars,
real-time rainfall and river monitoring and stronger coordination among
agencies responsible for weather forecasting, water resources and disaster
management.
Professor Humayun Kabir also called for increasing
budgetary allocation for disaster management to improve forecasting capacity,
strengthen preparedness and enhance emergency response.
He said the government should adopt long-term urban water
management strategies by reconnecting Dhaka’s canals, wetlands and surrounding
water bodies so that excess rainwater can be drained naturally during heavy
rainfall.
According to him, years of unplanned urbanisation have
disrupted the city’s natural drainage system through the encroachment of canals
and wetlands, indiscriminate filling of ponds and low-lying areas and the loss
of open green spaces.
To mitigate waterlogging in Dhaka, he suggested improving
the drainage system, restoring degraded wetlands, maintaining and creating
retention ponds, and promoting rainwater harvesting.
He also emphasised the need to promote rainwater
harvesting as part of the country’s climate adaptation strategy.
“Rainwater should be treated as a resource rather than
waste. If rainwater harvesting is promoted in public and private buildings, it
will not only reduce waterlogging but also ease pressure on groundwater,” he
said.
He suggested that the government begin implementing
rainwater harvesting systems in major public institutions, including the
University of Dhaka, before expanding the initiative nationwide.
Professor A.K.M. Saiful Islam of the Institute of Water
and Flood Management (IWFM), Bangladesh University of Engineering and
Technology (BUET), said Bangladesh experiences different forms of flooding,
including urban floods, river floods, flash floods, hill-torrent floods and
floods in low-lying plains, each requiring different management approaches.
Explaining the recent flooding, he said the event was
triggered by a monsoon depression that transported a large volume of moisture
from the Bay of Bengal into the eastern region of the country. As the
moisture-laden air rose over the hills, it produced intense orographic
rainfall.
“Chattogram recorded about 413 millimetres of rainfall in
a single day recently and nearly 850 millimetres over three days, exceeding the
carrying capacity of rivers and drainage systems,” he said.
Professor Saiful Islam said such extreme rainfall is
becoming more common as climate change increases atmospheric moisture,
resulting in more intense downpours.
He said heavy rainfall alone does not explain the severity
of urban flooding. Rapid and unplanned urbanisation, encroachment on wetlands
and canals, obstruction of natural drainage and poor solid waste management
have significantly increased flood risks in cities, he said.
He noted that many drains have already lost a large share
of their carrying capacity because they are clogged with garbage.
“No matter how many new drains are constructed, they will
not function effectively unless existing drains are cleaned regularly and solid
waste is managed properly with active public participation,” he said.
The experts also stressed the need for strict
implementation of urban master plans, building regulations and zoning policies,
alongside improved maintenance of drainage infrastructure and embankments.
They said accurate forecasting, science-based urban
planning, restoration of natural water bodies, wider adoption of rainwater
harvesting and stronger institutional coordination would together help
Bangladesh better cope with the increasing risks posed by floods in a changing
climate.
