Nepal flash flood raises concern in Bihar as Gandak level comes under watch

Nepal flash flood. File pic

A devastating flash flood in Nepal's Rasuwa district has prompted heightened vigilance in Bihar as authorities monitor the Gandak River and vulnerable areas along its course. The two regions are connected through a network of rivers that eventually carries water from Tibet into Bihar.

Floodwaters flow through interconnected river system

The flash flood struck Nepal around 9 a.m. on Wednesday, causing extensive damage in Timure, Syaphrubesi and Rasuwagadhi. Roads, bridges and other infrastructure were washed away, while several people were reported missing.

According to Nepali authorities, the sudden rise in water originated in Tibet. Preliminary assessments indicate that an obstruction formed by glacial debris may have suddenly given way, triggering the surge.

The river system broadly runs from Tibet through the Bhote Koshi, Trishuli and Narayani before the river enters India, where it is known as the Gandak. The Gandak eventually joins the Ganga.

Bihar authorities monitoring Gandak

The developments in Nepal have led to increased monitoring of the Gandak in Bihar. However, officials cautioned that flooding in Nepal does not automatically mean Bihar will face an immediate flood threat.

The impact in Bihar will depend on the volume of water travelling downstream, rainfall, additional inflows from other rivers and how barrages regulate the flow.

The Gandak enters Bihar through Valmikinagar in West Champaran, making the Valmikinagar Barrage a crucial point for monitoring and regulating the river.

Several districts kept under watch

West Champaran is among the key districts being monitored, particularly areas around Valmikinagar and the Gandak basin.

In East Champaran, low-lying and riverside areas could face increased risks of flooding and erosion if water levels rise. Gopalganj, which borders the Champaran districts, could also face a flood threat in case of a sudden increase in Gandak discharge.

Low-lying areas connected to the Gandak system in Siwan are also being monitored.

Parts of western Muzaffarpur could experience waterlogging or erosion if the river rises substantially. The Gandak then passes through Saran, making areas around Chhapra important from a monitoring perspective.

The river ultimately joins the Ganga near the Sonepur-Hajipur region, bringing riverside areas in Saran and Vaishali under observation.

Officials say immediate flood threat premature

Officials said the intensity of any flood wave could change as it moves downstream because of river capacity, distance, additional inflows and other hydrological factors.

The Valmikinagar Barrage therefore remains a critical point for tracking and managing the flow entering Bihar.

For now, officials said it would be premature to describe the Nepal flash flood as an immediate flood threat to Bihar. However, given the direct river connection, authorities are maintaining heightened vigilance along the Gandak's banks and in vulnerable low-lying areas.

(With inputs from IANS)