Explanation:

 Ghaghara, also called Karnali is a perennial trans-boundary river originating on the Tibetan Plateau near Lake Manasarovar. It cuts through the Himalayas in Nepal and joins the Sharda River at Brahmaghat in India. Together they form the Ghaghara River, a major left bank tributary of the Ganges. With a length of 507 kilometres (315 mi) it is the longest river in Nepal. The total length of Ghaghara River up to its confluence with the Ganges at Revelganj in Bihar is 1,080 kilometres (670 mi).It is the largest tributary of the Ganges by volume and the second longest tributary of the Ganges by length after Yamuna.