Nepalese rivers can be grouped into three
categories on the basis of their origin:
(1) antecedent to Himalaya, (2) after the Mahabharat. and (3) after the Churia range.
Antecedent rivers belong to the period prior to the rise of the
Himalaya. These rivers added their tributaries during or after
the Himalayan origin alongwith the developement of monsoon
climate. After the formation of Mahabharat hills, the antecedent
rivers changed their courses as Mahabharat stood as a barrier.
As a result, most of the rivers changed their courses either to
the east or west. Most of these rivers were responsible to
deposit the sediments in the Churia basin.
The major river systems namely the Koshi, the Karnali and the
Gandaki belong to the Gantecedent group. Rivers originating from
the Mahabharat range and cutting through Churia hills come under
the second group, these include Kankai, Bagmati, Kamala etc. The
third group of rivers originate from the southern face of the
Churia hills. For the purpose of commercial rafting, the
following rivers are in use.
1. Saptakoshi River System (East Nepal) 2. Narayani or Saptagandaki River System (Central Nepal) 3. Karnali River System (West Nepal)
Eight rivers in the three rivers systems are open for tourist
for rafting. The rivers are : - The Trishuli
- The Kaligandaki
- The Bheri
- The Seti
- The Sunkoshi
- The Karnali
- The Tama Koshi
- The Arun
