Karnali River Basin

Mountain range of Dhaulagiri

Mountain range of Nanda Devi

The Karnali River Basin lies between the mountain ranges of Dhaulagiri in Nepal and Nanda Devi in Uttarakhand. In the north, it lies in the rain shadow of the Himalayas. The basin formed by the river has a total catchment area of 127,950 km², of which 45% is in India. The population of the Basin districts in Nepal increased from 1.9 million in 1971 to 4.7 million people in 2001, almost a 250% increase over three decades. The average population density of the Basin area increased from 53 person/km² in 1981 to 87 persons/km² in 2001. There is a steady growth in the economically active population in the Basin districts. The average literacy rate has increased from a mere 7.5% in 1971 to 45% in 2001. The social status of the permanent households increased from 24% in 1991 to 31% in 2001. The Basin has a total road length of 2,640 km, but the pace of road development is slow.

Tributaries

Chhoti Gandak is a groundwater-fed meandering river originating near Dhesopool, Maharajganj district of Uttar Pradesh. It travels a distance of about 250 km and joins Ghaghara near Gothani, Siwan district of Bihar. The Chhoti Gandak River Basin is located between 26°00' to 27°20' N latitude and 83°30' to 84°15' E longitude. Right bank tributaries are Khekhra, Hirna, Jethan, Maun, Duhari, Kanchi and Koilar rivers; Khanua river joins from the left bank. The discharge of Chhoti Gandak is mainly controlled by rain, which is very high during the monsoon season and low during the summers. It has been observed that whenever precipitation is high in the catchment areas, there is flood in the downstream part of the Chhoti Gandak River Basin. The region exhibits upland terrace surface, river valley terrace surface, present-day river channel with narrow flood plains, natural levee, and point-bar deposits. All these geomorphic features are depositional in nature and made up of alluvium of different ages.
The main tributaries of the Karnali are: the Seti, the Bheri