1 Rivers of Nepal by Sushil Silwal

2 Map of Nepal

3 River Network

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5 Drainage System of Nepal  Nepalese rivers are not only cross the ranges of different altitudes but also cut deep gorges and valleys.  Most of these originate from Boarder Range, which cross the main Himalayas and flow down to Ganga River in India.  Some rivers like Kali, Humla, Arun and Sunkosi are older than Himalayan Mountain itself (Antecedent River)  Kali has formed the deepest gorge in the world (7000m +-)  Nepal has in total rivers with the length of 4500 km.  The ultimate destination of each river of Nepal is the Indian Ocean through Ganga River.  3 major River Basins (Gandaki, Kosi and Karnali)  These are snows – fed rivers also known as First category Rivers.  Mechi and Mahakali also fall in this category.

6 First Category Rivers:  Kosi River System (Sapta Kosi).  Major Tributaries: Tamor, Arun, Dudh Kosi, Likhu Koshi, Tama Kosi, Sun Kosi and Indravati.  Catchments area- 33,000 sq. km.  Hydro Power Capacity _ 22 million kW. Biggest river of Nepal  Ii was known as ‘sorrow of Bihar’ before the construction of Kosi- Barrage.  Ethnically this basin is called as Kirat or Limbuwan Region.

7 Gandaki River System (Sapta Gandaki)  Gandaki River System (Sapta Gandaki)  Flows between Gosainthan (Langtng) in the east to Dhulagiri in the west.  Catchments area- 26,000 sq. km.  Capacity of Hydropower – 21 million km.  It is also known as Narayani in Chitwan and Gandak in India.  Major tributaries: Trisuli, Buddhi, Marsyangdi, Madi, Kali, Seti and Daraundi.  Ethnically this basin is known as Magarat Region.

8 Karnali River System.  Karnali River System.  This is the longest river flowing inside Nepal  Flows between Dhaulagiri (east) and Byas – Rishi Himal (west).  Catchments area 49,000 sq. km.  It is called Ghagra in India.  Hydro Power Capacity 10 billion KW (UN survey 1961)  Major Tributaries: Humla, Mugu, Seti, Tila, Bheri, Babai within Nepal and Rapti in India.  Ethnically this basin is known as Khas Region.

9 Second Category Rivers  Second Category Rivers  Most of these rivers originate in the hilly areas of the Mahabharat Lekh.  Among them Kankai, Trijuga, Kamala, Bagmati, Tinau, Rapti, Banganga, Babai etc. are major ones.  These are comparatively low in length and volume than First Category Rivers, but these rivers swell during monsoon period.  During winter season the volume and velocity of water decrease.

10 Third Category Rivers  Most of the third Category Rivers originate from Churia Range.  These are helpful only for local level irrigation works especially in the Terai region.  Catchments area of these rivers is about 40,000 sq km.  The names of the major third category rivers are Mohana, Balan, Hardinath, Mawa, Ratuwa, Lohandra, Bheraha, Kothi, etc.