Nepal’s devastating floods are highlighting India’s exposure to transboundary rivers, extreme rainfall and fast-moving debris flows as climate change increases risks across the Himalayas.
Nepal’s deadly floods are raising concerns in India, where shared Himalayan rivers, extreme rainfall, fragile embankments and climate-driven hazards could worsen future disasters.
By MediaBites International Desk
NEW DELHI — Devastating floods in Nepal have exposed a growing risk for India, where rivers flowing south from the Himalayas can quickly turn extreme rainfall and mountain hazards into major disasters across the plains.
The warning comes as Nepal’s death toll from floods along its border with Tibet has crossed 1,000, according to the source material, highlighting the scale of increasingly dangerous events in the Himalayan region.
India and Nepal share a vast network of rivers, with more than 6,000 rivers and streams in Nepal, most draining south toward India and the Ganges. The major transboundary systems include the Kosi, Gandaki, Karnali and Mahakali, while smaller rivers such as the Bagmati, Kamala, Rapti and Babai can produce rapid and unpredictable flooding.
Bihar is the Indian state most exposed to flooding, with about three-quarters of north Bihar classified as flood-prone. Many of its major rivers originate in Nepal, including the Kosi, Gandak, Bagmati and Kamala.
The danger also extends into eastern Uttar Pradesh, where the Ghaghara, Rapti and Gandak regularly affect districts including Gorakhpur, Bahraich, Lakhimpur Kheri and Shravasti. Uttarakhand and parts of northern West Bengal also face risks from rivers originating or flowing through the Himalayan region.
But experts caution against viewing flooding in India simply as water flowing downstream from Nepal. The severity of a disaster depends on rainfall in both countries, river levels, embankments, barrages, drainage systems and development on floodplains.
“For the peak flow arriving at the border, largely Nepal’s rainfall; for the severity of flooding once it arrives, at least as much on Indian conditions,” said Saswata Sanyal of the International Centre for Integrated Mountain Development.
The 2008 Kosi disaster illustrates the danger. Nearly 400 people died after the river breached an embankment in Nepal and flooded parts of Bihar, even though the river was carrying only about a tenth of its carrying capacity, according to Rajiv Sinha, a professor at IIT Kanpur. The disaster was attributed to an embankment failure after years of inadequate maintenance.
India can receive between roughly 12 hours and two days of warning for conventional monsoon floods, depending on the river. Flash floods from smaller catchments can arrive within hours, while a debris flow or landslide-dam burst can move even faster. During the latest Nepal floods, a peak surge from Rasuwa reached near the Indian border in about seven and a half hours.
India and Nepal already share real-time rainfall and river-level information, but experts say gaps remain in monitoring fast-flowing catchments, forecasting systems and information about embankments, sediment and river-channel changes.
Scientists also warn that the region’s hazards are becoming more complex. Extreme rainfall is intensifying, while warming temperatures, degrading permafrost, glacial lake outbursts, rock-ice avalanches and heavier sediment loads could make floods faster and harder to predict.
The central concern for India, experts say, is therefore not simply how much water crosses the border from Nepal, but how the two countries manage an increasingly volatile Himalayan river system.
Better shared data, early-warning systems and coordinated river management could help reduce the risks for communities on both sides of the border.
