Gandak Surge Breaches Embankments in Bihar and UP, Flood Risk Persists
Heavy rain in Nepal's Gandak catchment caused record flows and embankment breaches in Bihar and Uttar Pradesh, prompting emergency repairs and alerts.
A flash flood in the Gandak river basin has left several districts of Bihar and Uttar Pradesh facing a flood threat after embankment breaches, even as water levels at the Valmikinagar barrage began to recede on Tuesday.
The surge followed heavy, short-duration rainfall in the Nepalese catchment of the Gandak, which pushed a massive volume of water downstream. At the Valmikinagar Gandak Barrage, discharge touched 5,43,500 cusecs at 6 am on Tuesday. The river ran above 500,000 cusecs for 13 hours and above 400,000 cusecs for 32 hours, sending floodwaters into West Champaran, East Champaran, Gopalganj, Saran, Muzaffarpur and Vaishali.
Rain across the border districts of West Champaran, East Champaran and Gopalganj on September 26 and 27 had already raised levels in the lower reaches before the peak arrived.
The Water Resources Department said that while the barrage peak was slightly below the 2024 record of 562,500 cusecs, the Bagaha gauge site set a new historical high. The water level reached a Highest Flood Level of 91.25 metres, surpassing the previous mark of 90.90 metres set in 2024 by 35 cm.
The volume of water strained the embankments, causing seepage, piping and overtopping. Field teams secured 169 seepage and piping points through emergency repairs. However, between the midnight hours of September 28 and 29, three critical breaches occurred.
In West Champaran, two breaches were reported on the left bank of the Champaran embankment. The first was a minor breach of about 10 metres caused by sudden subsidence at the 4 km mark in Khairatwa village under Bagaha-1 block. Spilling water is spreading through nearby fields and is expected to re-enter the river around the 9.50 km mark, though low-lying areas in Agastya, Khairatwa and Chandrapur villages face possible inundation and disrupted connectivity. A second breach occurred at Phuliyakhar village in Bairia block. Another breach was reported on the right bank in Kushinagar district of Uttar Pradesh.
By 8 am on Tuesday, the Valmikinagar barrage showed a clear receding trend, with downstream discharge down to 191,200 cusecs. Upstream and downstream gauge levels stood at 356.70 feet and 354.10 feet. The Devghat gauge station in Nepal recorded 219,677 cusecs (6.14 metres) at 6:25 am, with a falling trend.
While upstream levels continue to drop, downstream reaches are seeing a temporary rise as the surge moves toward lower areas.
The Water Resources Department and the West Champaran district administration have deployed teams for breach repairs and emergency protection works. Four executive-engineer-led response teams were dispatched overnight to Bagaha, Bettiah, Motihari and Gopalganj to oversee anti-erosion measures and structural interventions, working alongside engineering staff already on the ground. Senior officials are monitoring the response round the clock.