Record October rainfall and its implications

Residents in Dhaka woke up to find the city under water on October 1 when there was a staggering 132 millimetres of rainfall in just six hours between midnight and 6:00 am. By the end of the day, the total rainfall reached 203 millimetres, the highest recorded in the country during this period. October 1 is Ashwin 16 on the Bengali calendar with Ashwin 1 marking the late Autumn season. Bangladesh is not used to seeing such cloudbursts in late Autumn. It is unimaginable for anyone that rain in this season will turn streets into streams, leave low-lying neighbourhoods inundated, and bring the daily life to a halt for millions of residents.

 Why is it happening? Experts and environmentalists believe it is one of the bizarre developments triggered by climate change. They believe what Dhaka witnessed on October 1 cannot be seen in isolation. It is part of a global trend where climate change is responsible for erratic weather patterns.

Bangladesh has always been vulnerable to natural disasters like floods and cyclones, but climate change is amplifying both the frequency and intensity of the disasters. The country is not alone to suffer from climate change impact. The entire South Asian region is witnessing a rise in frequency and intensity of natural disasters. Cities like Mumbai in India and Karachi in Pakistan have also faced record-breaking rainfalls in recent years.

But in Dhaka, rapid unplanned urbanisation, clogged drainage, loss of wetlands and plastered surface area worsen the situation. Rainwater here finds fewer escape routes to pass. So even moderate rainfall results in waterlogging and when 132 millimetres of water falls in six hours, the city's system is overwhelmed.

The implications of heavy rain often go beyond temporary waterlogging. Water stagnation affects public health, damages infrastructure and reduces productivity. It creates fertile breeding grounds for mosquitoes, raising the risk of dengue, chikungunya and other vector-borne diseases. For the urban poor who live in slums or other informal settlements, downpour means losing bedding, clothes, and cooking materials to rainwater. The economic cost of such a cloudburst is immense, though often underestimated. It forces small businesses to shut down, causes loss of perishable food items, and compels daily wage earners to stay home. For example, the October 1 downpour inundated most parts of the Karwanbazar kitchen market, damaging huge quantities of goods and leaving the traders struggling to pump out water from the market. The rain-induced transport paralysis translates into crores of taka in lost productivity. Delays in delivery of goods, absence at workplaces and damage to vehicles and property are not fully measured, but anyone can guess that cumulatively they weigh heavily on the national economy.

Now the pressing question is what can be done to prevent Dhaka from sinking further into crisis with every downpour. Urban planners have long been arguing that the city's wetlands and canals must be protected and restored. Despite their call, unplanned real estate development has filled up natural drainage channels over the past few decades, leaving rainwater with fewer places to go. The Buriganga, Turag, and Balu rivers, once considered lifelines for Dhaka, are now choked with encroachments and pollution while many of the city's drains are clogged with solid waste and polythene bags. The city requires urgent measures to restore its natural water flows. It also needs massive improvement in its drainage system and drainage management. At the same time, citizens must be encouraged not to dump waste into canals and drains.

The October 1 rainfall also highlights a lapse in our climate adaptation policies at the national level. Bangladesh has earned international recognition for its climate resilience strategies in rural areas, particularly in cyclone preparedness, but urban resilience is lagging behind. The government must prioritise urban climate adaptation, ensuring that infrastructure keeps pace with changing climate realities.

rahmansrdk@gmail.com