Everything you need to know about the Koshi flood impact in Nepal

Federal, provincial and local governments can do their best to house human settlements in safer locations.

Birat Anupam

  • Read Time 3 min.


Itahari: On Wednesday morning, August 3, at around 4 am, the embankment of Dumribote of Belaka Municipality-8 of Udayapur district was breached by Koshi river. The largest river of Nepal started to flow downward and settlements of ABC, Bhatepul, Durga Mandir, Ramnagar, Chiliya, among others were inundated by the Koshi current. Ward number 1, 2, 3, 8 and 9 of Belaka Municipality and ward number 9 and 6 of Barahakshetra Municipality of Sunsari were affected. 

This raises some burning questions about the recent Koshi flood crisis in Province 1. 

Was the Koshi flood a new one?

Not actually. Flooding in Koshi river is something that occurs almost all monsoon seasons. However, breaching of the embankment takes place occasionally at different sections of Koshi river. The waterway of the newly diverted Koshi river was also a part of erstwhile Koshi course. The local elders say the Koshi flowed through the same course some 34 years ago. ”I have seen Koshi flowing through this area until 2045 BS”, said Deb Majhi, a local indigenous elder living on the bank of Koshi river. Majhi said the Koshi changed its course eastwards toward Sunsari after 2045 BS.

Why is Koshi a volatile river in terms of its flow? 

The book titled Koshiko Katha, which roughly translates as the ‘story of Koshi,’ authored by Nepal’s first civilian Prime Minister Matrika Prashad Koirala, says that Koshi would flow eastward during his childhood days. ”We had to cross the Koshi river to reach Birpur of Sunsari from eastern Sunsari,” Koirala has written in the book. These days Birpur does not require Koshi crossing for its arrival from eastern side of Sunsari. Likewise, various scholars have said that Koshi would flow some 100 kilometers eastwards some centuries ago. This trend shows that Koshi is a historically volatile River which changes its course at times at its will. Therefore, volatile Koshi is not a new phenomenon from every angle. 

How many people are affected by the recent Koshi flood?

Media reports from Nepal’s mainstream press have shown the figure of Koshi displacement of around 20,000 in Udayapur and Sunsari districts. More displacement is feared in Saptari district as well. However, local representatives disagree with this figure. Yes, there is displacement. However, the number is not large. This is mainly because people living along the shores of Koshi river have alternative homes outside Koshi banks. Some of them are temporary settlers living for their crops and cattle. Likewise, the land people live is public land. They do not have their ownership there. Therefore, strong infrastructures are not built.

However, there is a trend of selling the land to outsiders in the name of cheap farmlands, showing the optimistic future of Koshi High Dam. Once Koshi High Dam is built, the Koshi would not be a problem like before; this is the line of persuasion to ordinary public from many land brokers and land mafia. 

According to the locals, innocent people are duped into purchasing public land by promising schools, police posts and the like. Luckily, no human loss has been reported as of Saturday. 

What can the three tiers of government do to tame the Koshi river? 

Nepal’s federal, provincial and local governments can do their best to house human settlements in safe locations. However, they can do literally nothing to tame this river. This is owing to the Koshi Agreement with Nepal’s southern neighbor that shares Koshi river downstream. The Koshi Agreement was first made on 25 April 1954.

There is another consecutive Koshi Agreement updating the previous one on 19 December 1966. In the agreement, the Koshi land was leased for 199 years to India. This diplomatic agreement has made India a primary actor in the Koshi river. Therefore, in order to tame Koshi river Nepal needs to have diplomatic dialogue and agreement with India. The 1150-meter-long and 10-meter-wide Koshi Barrage was constructed in 1959 and it has been operated since 1962. The 56 sluice gates of the barrage are in the control of India officials. 

Another factor of hardship of taming Koshi river is its speed and silt carrying capacity. As Koshi flows from north to south, the speed is bigger with a bigger volume of silt. For example, a report titled ‘Understanding Sediment Management’ compiled by The International Center for Integrated Mountain Development (ICIMOD), says Koshi has ‘exceptionally high sediment carrying capacity’. The report says Koshi represents just nine percent of water of Ganges but the sediment representation is 25 percent. Many termed Koshi as the second largest sediment-carrying river after China’s yellow river named ‘Huang He.’ 

According to the ICIMOD report, Koshi carries 100-135 million tons of silt in a year. The erosion rate of Koshi is also high. According to a report at The Journal of Science, Engineering and Technology of The Kathmandu University, the Koshi erosion rate at Barahakshetra area was 169 ton/ha.yr.