Water from upstream has caused Surma and Patlai rivers in Sunamganj to overflow, flooding at least 25 hectares of cropland in Tanguar Haor.
The Bangladesh Water Development Board (BWDB) on Saturday said the water level in the Surma River has risen by 188 centimetres in the last 24 hours.
“The water levels of major rivers in Sunamganj are increasing due to moderate to heavy rainfall in northeastern Bangladesh and adjoining states of Assam and Meghalaya in India,” said Executive Engineer Md Shamsuddoha of the local BWDB.
But they are still flowing below their danger levels, he added.
The town of Cherrapunji in Meghalaya recorded 191mm of rainfall in the last 24 hours, according to the BWDB.
A dam at Tanguar Haor under Tahirpur upazila got swept away by water from the Patlai River on Saturday, submerging a huge amount of cropland.
Farmers had been trying to protect the dam on their own for the last few days.
Upazila Nirbahi Officer Rayhan Kabir said there is 120 hectares of cropland at Tanguar Haor and 25 hectares has gone underwater.
Sunamganj BWDB Executive Engineer Jahurul Islam said the broken dam was not erected by the board.