It subsequently flows southeast through a comparatively open valley, its course strewn with large boulders against which the water foams violently.

The Raidak confluences with the Brahmaputra at chainage 327 km in Kurigram District in Bangladesh,[4][5][6][7] where it is sometimes referred to Dudhkumar River.

[1][9] The 336MW Chukha hydel project, which harnesses the waters of the Wang Chhu or Raidak River, was historically one of the largest single investments undertaken in Bhutan, and it represented a major step toward exploiting the country's huge hydroelectric potential.

Located between Thimphu and the Indian border, a 40 metres (130 ft) diversion dam was built at Chimakoti village, 1.6 kilometres (0.99 mi) upstream of the confluence of the Ti Chhu and Wong Chhu rivers.

From the dam water was diverted through 6.5-kilometre (4.0 mi) long tunnels to a fall of more than 300 metres (980 ft) to Chukha power house for generation of electricity.