Bhola town protection dyke collapsed at Nasir Majhi point under Dhania union of Sadar upazila Monday afternoon, inundating all the nine villages of the union.
Besides, floods engulfed 11 more villages in Charfashion and Daulatkhan upazilas of the district the same day.
In Bhola Sadar upazila, around 50 feet area of the 18-kilometre-long town protection dyke along the Meghna River collapsed at around 5:00pm as water level of the river marked a sharp rise due to high tide under the impact of full moon.
Locals alleged that they saw cracks developed in the dyke at noon and informed the authorities concerned through Dhania UP Chairman Emdad Hossain Kabir, but they didn't take necessary measures to protect the dyke.
They said some portions of the embankment are also vulnerable to collapse as maintenance was not done properly since its construction in 1999.
Sadar Upazila Chairman Mosharraf Hossain along with WDB officials visited the affected villages yesterday. He reassured the villagers of repairing the damaged portion as soon as possible
In Charfashion upazila, tidal surge flooded eight more villages in the upazila on Monday. The affected villages are North Naziruddin and South Naziruddin, Kukrimukri, Mujibnagar, Char Shiva, Char Batila and Dhal Char.
Samraj fish landing station, Samraj Bazar, ice mills and 10 fish warehouses under Madras union in the upazila have also gone under water.
In Daulatkhan upazila, three more villages got flooded, affecting several hundred villagers. The flood-hit villages are Shariatpur, Hajipara and Bhabanipur.