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From the high Himalayas to the plains, one of the largest tributaries of the Ganga has the power both to unleash disaster and to transform the country’s economy

Area in red marks the Kosi river basin [image by CC BY-SA 3.0 / Wikipedia]


The Koshi River drains a large part of east-central Himalayas, flowing from Tibet and through Nepal before joining the Ganga in northern Bihar in India, which eventually flows to the Bay of Bengal. As one of the largest tributaries of the Ganga, the Koshi drains about 75,000 square kilometres — almost the size of Bhutan. It is one of the largest sediment-carrying rivers in South Asia. The basin boasts the world’s tallest mountain peaks including Mount Everest. In Nepal, it is called the Sapta Koshi — or seven Koshis — because seven Himalayan rivers merge to create it. The Koshi  is well known for its floods and capricious behaviour, having displaced millions in Nepal and India in recent years.

Our sister website’s Nepal Editor Ramesh Bhushal and photographer Nabin Baral travelled along the tributaries of the Koshi River from near Tibet to the Indian border to report on the challenges faced by people living in the region.

Part 1

Hazards in the high mountain

Tsho Rolpa Glacial Lake: an example of the potential threat behind the beautiful glacial lakes in the Rolwalling valley, Nepal. Tsho Rolpa is one of the high priority potentially dangerous glacial lakes in the Nepal Himalayas. As a result of climate change and fast retreat of the glacier, the lake expanded from 0.23 square kilometres to 1.53 square kilometres between 1960 and 2010, according to Pradeep Mool of ICIMOD. The fast retreating glaciers and adjoining glacial lakes increase the threats of glacial lake outburst flood (GLOF). GLOFs most likely would cause extensive damage to people and property downstream. This image was taken on May 10, 2010 (Photo by Nabin Baral)

Part 2

Roaring rivers, thirsty people

Children walk half an hour to fetch water from a spring during the dry season in Udayapur, south-eastern Nepal (All photos by Nabin Baral)

Part 3

Dreams of hydropower dollars

Work is yet to resume at the Upper Tamakoshi dam site after the road was destroyed by last year’s earthquake. Image from Dolakha, Nepal. [All photos by Nabin Baral]

Part 4

River on the floodplains — best friend and worst enemy

In Sunsari, Nepal, close to the border with India, a farmer cultivates land that was submerged in sand during the Koshi flood of 2008 [all photos by Nabin Baral]


The Bamboo Rafters

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