Heavy upstream rainfall may trigger floods in July-August

Bangladesh is likely to experience flooding in the Brahmaputra and Meghna river basins during July and August this year due to heavy rainfall in their upstream catchment areas, according to the Flood Forecasting and Warning Centre (FFWC).
"Bangladesh remains vulnerable to flooding. Flooding is likely to occur in the Brahmaputra and Meghna river basins during July and August this year due to prevailing climatic conditions," said Sarder Udoy Raihan, executive engineer at the Flood Forecasting and Warning Centre (FFWC) under the Bangladesh Water Development Board (BWDB).
Raihan said heavy rainfall across the major river basins and their upstream catchment areas during this period often triggers flooding in Bangladesh.
He stated that historical records show this mid-monsoon period has produced some of the country's most devastating floods.
During the historic 1988 Bangladesh flood, exceptionally heavy monsoon rainfall, which peaked between August and September, inundated approximately 82,000 square kilometers, nearly 60 per cent of the country's total land area.
Similarly, the historic 1998 flood lasted for more than two months, spanning July and August. The disaster claimed more than 1,000 lives and temporarily displaced or stranded around 30 million people.
Experts note that the synchronisation of peak flows in the Brahmaputra and Meghna river basins poses the greatest flood risk.
In 2004, a severe flood intensified rapidly when peak flows in the two rivers coincided in late July, inundating nearly 30,000 square kilometres in the country's northeastern region alone.
More recently, the 2022 floods in the Meghna basin and the devastating floods of 2024 collectively affected more than 13 million people, underscoring the persistent threat posed by heavy upstream rainfall.
Raihan further said that the FFWC can currently issue flood forecasts for inland river basins 10 to 15 days in advance, while forecasts for coastal rivers can be provided up to three days ahead.

Commenting on the current river conditions, Raihan said low-lying areas of the Brahmaputra basin are already experiencing flooding, although water levels are expected to stabilise within the next five to six days.
He added that the Meghna river basin is likely to remain stable over the coming days, as no significant rainfall has been recorded across the basin or its upstream catchment areas.
The FFWC executive engineer also said a low-pressure system may develop over the Bay of Bengal later this month, potentially triggering flash floods in the low-lying coastal areas of Bangladesh.
According to the FFWC's flood forecast issued on Thursday, water levels in the Brahmaputra-Jamuna river system declined over the past 24 hours but are expected to rise over the next four days before stabilising on the fifth day.
Over the next four days, water levels in the Brahmaputra-Jamuna river system may reach the warning level in Kurigram, Gaibandha, Jamalpur, and Bogura districts, with flooding likely in some adjacent low-lying areas.
Water levels in the Ganges-Padma river system are expected to continue rising over the next five days but are likely to remain below the danger level.
The forecast also said, over the next 72 hours, the Surma-Kushiyara (Upper Meghna) river system may continue to flow at warning levels in Sylhet and Sunamganj districts, while some adjacent low-lying areas are expected to remain inundated.
Water levels of the Teesta River at Dalia (Nilphamari) and Tarapur (Lalmonirhat), the Kushiyara River at Fenchuganj (Sylhet) and Markuli (Sunamganj), and the Someshwari River at Kolmakanda (Netrokona) are at their respective warning levels.

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