A flood protection embankment along the Atrai River in Manda upazila of Naogaon district collapsed following a water level increase, rendering 1,500 families in a number of villages stranded.
Besides, 1000 bigha of Aush and Aman cropland were inundated.
The Atrai River was flowing 100 cm above the danger level due to the incessant rains for the last several days.
The local administration has started dumping sand bangs along the banks of the river to protect the embankment.
Around 1,500 families are affected as Nurullabad, Parnurullabad, Prasadpur, Baibulla and Bishnapur unions have been flooded due to the collapse of the embankment in four points.
According to the local water development board, the river water started to swell from Sunday and was flowing 100 cm above the danger mark till Tuesday afternoon.
The river water will continue to increase today, it said.
Jahangir Alam, member of Nurullabad union parishad, said 1000 families of seven villages under the union have been trapped due to the flood water.
Manda Upazila Nirbahi Officer, Laila Anjuman Banu, said the authorities concerned have visited the flood-affected areas and the dumping of sandbags is going on in full swing.