Beginning high up in Tibet and snaking its way through Nepal and India, the Koshi River eventually empties into the storied Ganges near the town of Kursela after a journey of 450 miles. Notoriously fickle about its exact path, the river is often called “the Sorrow of Bihar” because of its devastating floods during monsoon season near Bihar, India. This prompted the building of a barrage (aka a weir or sluice) near Nepal’s border with India in the late 1950s.  

Equipped with 56 gates spaced across a 1,150-meter (3,772-foot) expanse, the barrage has had some success managing the temperamental waterway, although Nepal’s largest river will likely never be completely tamed— in the past 100 years alone it has moved nearly 150 kilometers (93 miles) laterally.

The barrage was designed to last for 25 years, but more than 60 years later, a more permanent structure has yet to be built. The fragility of the barrage was revealed in 2008 when the eastern embankment collapsed, causing a major flood that left more than 3 million people homeless.

Although the barrage is entirely within Nepal’s borders, India has the sole responsibility to maintain it, and funds are customarily scarce for repairs and upkeep. Nevertheless, the barrage has performed admirably despite being well past its prime and having to withstand pressure from up to 135 million tons of silt each year.

The barrage has also become something of a noted social venue for fishermen, tourists, birdwatchers, locals, and endangered Ganges River dolphins, which position themselves in front of the open flood gates to catch funneled fish. These dolphins are essentially blind since the silt-filled water is too opaque for them to rely on sight. They are distinctive in many other ways as well, possessing elongated beaks and flippers, a slightly unsettling misshapen appearance, and occasionally a pinky hue. 

Spectacularly shy and rare (only approximately 2,000 dolphins are known to exist in the Ganges and Indus River systems), one can stand on the Koshi Barrage and easily spot at least half a dozen at a time feeding and playing. As such, being barraged by dolphins makes a visit worthwhile.