A collaborative approach to build resilience to flash floods

The key lesson from this year’s flood is that floods affect lives in both rural and urban areas. Photo: Mohammad Minhaj Uddin

The recent catastrophic floods that swept through the Southeastern parts of Bangladesh are unprecedented in the past three decades in the region. People of these areas are not accustomed to such severity and suddenness. As they were utterly unprepared, it was truly a 'flash' flood for them. 

The crisis unfolded when the region experienced rainfall between 200mm and 493mm within three days during the third week of August. This excess rainwater rushed downstream through rivers and overflow channels. The Gumti, Muhuri, and Feni River embankments breached in several places, causing extensive flooding in surrounding districts. 

The upstream situation in India's Tripura region also played a significant role. With over 500mm of rainfall recorded there, water levels surged to unprecedented heights. The breach of the Dumboor Dam upstream of the Gumti River exacerbated the flood, severely impacting nearby communities. While residents behind the dam are accustomed to the risk of flash floods during monsoon seasons and evacuate accordingly, people in the surrounding affected districts bore the brunt of the unexpected disaster. 

In Haor areas like Sunamganj, flash floods are an annual occurrence, and local communities have adapted to them. However, the severe 2022 flash flood— unseen in 122 years— brought unexpected devastation. At that time, power outages, mobile network disruptions, inundated highways, and a shortage of boats compounded the distress.

The recent flood has revived similar fears. The question arises: why did not the water flow as it normally would? The answer lies in obstructed water paths; creeks have been filled or encroached upon, and roads constructed with undersised culverts impede the flow. Consequently, water has only partially receded.

Particularly in Noakhali, the water has not drained quickly enough. When floodwaters reach Noakhali, they flow toward coastal rivers, which are often full due to tides. Water cannot flow out during high tides, and only recedes for about eight hours a day during low tides, slowing the drainage process.

Previously, a large regulator in Musapur at Companiganj upazila of Noakhali, held back water, allowing it to drain gradually and preventing saltwater intrusion. However, with the regulator no longer functional, high tides bring saltwater into the region, devastating agricultural areas.

However, Noakhali's water-logging issues are long-standing due to complex hydro-morphological factors.

The city was built on reclaimed land from the sea, with cross-dams built on the Meghna River in 1957 and 1967 by the Water Development Board. These facilitated the emergence of over 1,000 km square of new land, creating the foundations for modern Noakhali.

Rising sea levels have made the area "bowl-shaped," causing water to collect during heavy rains. The Water Development Board has struggled to solve the drainage problem. Without the Musapur regulator and with strong currents, water is draining even more slowly, highlighting the need for a long-term solution.

The floods caused severe destruction across sectors such as housing, infrastructure, agriculture, livelihoods, WASH, health, and education. According to a study by the Centre for Policy Dialogue (CPD), estimated damage is Tk14,421 crore or Tk1442.1 billion.

In terms of infrastructure, responsibility is split between the Roads and Highways Department and the Local Government Engineering Department (LGED). One limitation of LGED's approach is its focus on road infrastructure without sufficient attention to hydrological flow, the impacts of climate change, or adequate culvert sizing. Consequently, water stagnates on bitumen roads, which weakens the bitumen and degrades road surfaces. The poor condition of these roads also delayed flood rescue efforts.

Unlike Sunamganj, where numerous rivers allow for boat transport during floods, Southeastern regions lack alternative routes, compounding transport challenges. The floods damaged over 15,000 km of roads, with repair costs estimated at Tk3.48 billion.

Local governments struggle to meet infrastructure rehabilitation needs, as budgets are insufficient to cover the scale of the disaster. Although the government has allocated some maintenance funds, financial support must go beyond immediate repairs to support resilient infrastructure capable of withstanding future disasters.

Nearly 340,000 houses require varying levels of repair, and resilience should be a priority in their reconstruction. The reality is that such disasters will not cease. Already in 2024, Bangladesh has seen five significant events of this kind. Climate change only exacerbates these occurrences, making it crucial to incorporate loss and damage considerations in our assessments.

Losses, such as the 71 lives lost, are irreversible. While infrastructure and crops may be restored, such irreplaceable losses highlight the importance of planning for the future. Rebuilt structures should incorporate elements that improve resilience against future floods. Vulnerable infrastructure can be modified, but new construction must prioritise sustainability and resilience, with retrofitting as an option where feasible.

At BRAC, we respond swiftly to emergencies. However, rehabilitation efforts often lack adequate NGO involvement in government-led programmes and advocacy. While NGOs may not have extensive financial resources, they do bring human resources– an area where government capacity may be stretched.

Collaborative efforts between government and NGOs could enable rapid progress. More coordination is needed to incorporate NGOs into rehabilitation processes effectively, and foreign aid should be channelled to both NGOs and government initiatives.

This year's floods have severely impacted agriculture, fisheries, poultry, and livestock, with estimated losses reaching Tk458 billion. Over 259,000 hectares of cropland have been damaged, creating a potential food security crisis for countless farmers.

In response, accessible financial support through crop insurance, microfinance options, and soft loans is essential for those rebuilding their livelihoods. Job creation, especially for vulnerable groups, can be supported through infrastructure repair projects and agricultural recovery initiatives.

The key lesson from this year's flood is that floods affect lives in both rural and urban areas. Swift action to address drainage and water-logging is crucial.

Clearing obstructions from khals (natural drainage channels), excavating clogged canals, and adding more drainage openings on roads prone to flooding are effective steps. By collaborating with local authorities and communities, we can ensure that actions are prioritised appropriately. Regular maintenance will keep drainage systems functional over the long term.

Improved water flow will protect vulnerable areas from future flooding. Strengthening information exchange on flooding between neighbouring countries is also vital to enhance preparedness. Warning systems and forecasting mechanisms must be boosted to ensure resilience in future events.

Sketch: TBS

Md Liakath Ali, PhD is the Director, Disaster Risk Management Programme (DRMP), Urban Development Programme (UDP), and Climate Change Programm (CCP) at BRAC.

Disclaimer: The views and opinions expressed in this article are those of the author and do not necessarily reflect the opinions and views of The Business Standard.