The Himalayan region abounds in glaciers. Most of the big glaciers
lie in the eastern Himalaya. The western Himalaya receives only
a small amount of rainfall but heavy snows in winter. The source
of some of Nepal's mightiest rivers are in fact glaciers.
Nepal's largest glaciers lie in the Khumbu and the Makalu ranges. Khumbu has the biggest glacier and Langtang the longest. Kanchenjunga, Yalung, Nupchu and Lamtang are some other glaciers in the eastern Himalaya. Tukche and Hidden Valley glaciers are in the central Himalaya but these are comparatively small. Eroding the land along their course, the glaciers have left their mark in the Himalayan landscape in the form of gigantic cirques and rock basins, hanging valleys and morainic ridges.
Rivers:
Nepal's rivers can be broadly divided into three categories in accordance with their origins. The rivers arise either in the Himalaya, the Mahabharat Range or the Churia Hills.
The first category comprises the three main river systems of the country -- the Koshi, Gandaki and Karnali river system, all of them originating from the glaciers and snow-fed lakes of the Himalaya.
The Gandaki river system in central Nepal consists of the Kaligandaki, Budhigandaki, Marsyangdi, Trisuli, Seti, Madi and Daraundi Rivers. The Kaligandaki is the longest river and the Trisuli is the main tributary of this system. The Kaligandaki originates in Mustang and converges with the Trisuli at Deoghat in Chitwan. The river is then called the Narayani and goes on to meet the Ganges.
The Karnali river system in western Nepal consists of the Humla Karnali, Mugu Karnali, Seti and Bheri rivers, and is the longest river system in the country. The Humla Karnali, which arises in Tibet, is the main tributary. After entering India, this river assumes the name Gogra.
The Mechi, Mahakali, Bagmati, Kamala, and Rapti, which have their origin primarily in the Mahabharat range, constitute the rivers of the second category. The Bagmati, which rises at Bagdwar and drains out through the Chobhar gorge, is the principal river of Kathmandu Valley.
Streams and rivulets originating from the Churia hills make up the third category; these streams rely on monsoon rains and are otherwise dry.
Lakes:
There are number of lakes of glacial and tectonic origin in Nepal. The mountain lakes Rara, Phoksundo and Phewa are majestic in both size and beauty.
Rara Lake, in Mugu district of western Nepal, is the country's largest lake. Phewa Tal at Pokhara is the most popular among tourists. Lake Phoksundo in Dolpa district is large but less known than Phewa Lake due to its difficult approach. Rupatal and Begnastal (Pokhara), Gaduwaltal (Chitwan), Satyavatital (Palpa), Khaptadtal (Doti), Barhakunetal (Dang), Surma Sarobar (Bajhang) and Tilicho (Manang) are some of Nepal's other well-known lakes.
Gosainkunda and other lakes in the Langtang Himal region are of religious significance (for more details please refer to the section "Places of Pilgrimage").