The geographical structure of the country is such a marvel of nature; which is one unique place in the world. The snow-capped mountains receive snow throughout the year which helps major glaciers and glacial lakes to form. This huge amount of glaciers serve as the source of the major perennial rivers in the country. The major river system of the government originates from glaciers except for small streams and rivers. The tall mountain range on the northern belt of the country serves as a barrier for most of the moisture coming from the Indian ocean.

This blockage helps the land to receive rainfall and snowfall in the country thus leading to the formation of streams of small rivers which pass through the hilly region of the country. The hilly regions of Nepal are comprised of hills, valleys, and basins. These areas are rather loosely populated because of the rough topography.

This region consists of the major forests in Nepal and it is rather difficult for people to settle in this region. The forests in this region provide various small streams which join the primary river system in the country. These streams of small rivers have a very significant effect on the major rivers as all of them are not perennial. During the monsoon, the volume of water flowing in these rivers is huge compared to the other seasons.

The river system flows through this hilly region to the plains of the south. It is in this region the rivers deposit the eroded materials making the land alluvial and fertile. Nepal's river system is very important in the region for its natural, cultural, and religious reasons.

In the Vedic culture, rivers have been an important water body for all of these reasons. They have been worshipped throughout the region for the role these rivers play in the sustainability of life, whether it is for plants or animals.

Koshi River The Koshi River, also known as Saptakoshi, is the largest river in Nepal and is an important source of water for irrigation and hydropower. It originates from the Tibetan plateau and flows through Nepal and India, covering a distance of 720 km. The river is home to over 200 species of fish, including the famous Golden Mahseer, and supports a variety of other aquatic life.

Arun River The Arun River is the largest tributary of the Koshi River and is known for its spectacular rapids and scenic beauty. It originates in Tibet and flows through Nepal for a distance of 335 km. The river is home to a variety of aquatic life, including the endangered Gangetic dolphin, and supports the livelihoods of many local communities.

Dudh Koshi River The Dudh Koshi River, also known as Milk River, is a tributary of the Koshi River and is known for its milky-white color. It originates from the Khumbu region and flows through the Sagarmatha National Park, providing water for the local communities and supporting a variety of wildlife, including the snow leopard.

Karnali River The Karnali River, also known as Ghaghara in India, is one of the longest rivers in Nepal, covering a distance of 507 km. It originates in Tibet and flows through Nepal and India, supporting the livelihoods of millions of people. The river is home to over 200 species of fish, including the endangered golden mahseer, and supports a variety of other aquatic life.

Seti River The Seti River, also known as White River, is a tributary of the Karnali River and is known for its crystal-clear water and serene beauty. It originates in the Annapurna region and flows through Pokhara, providing water for irrigation and supporting a variety of wildlife, including otters and fish.

Trishuli River The Trishuli River is a major tributary of the Narayani River and is known for its exciting rapids and stunning scenery. It originates in Tibet and flows through Nepal for a distance of 120 km, providing water for irrigation and hydropower. The river is home to over 100 species of fish, including the famous Golden Mahseer, and supports a variety of other aquatic life.

Bheri River The Bheri River is a major tributary of the Karnali River and is known for its clear water and rich aquatic biodiversity. It originates in the Dhaulagiri range and flows through Nepal for a distance of 144 km, supporting the livelihoods of many local communities.

Mahakali River: The Mahakali River is a transboundary river that flows between Nepal and India. It originates in the Himalayas and flows through the western region of Nepal. The river is an important source of water for irrigation and hydropower generation in both Nepal and India. The Mahakali River is also home to a variety of fish species and other aquatic life.

Marshyangdi River The Marshyangdi River, also known as Raging River, is a major tributary of the Trishuli River and is known for its turbulent rapids and scenic beauty. It originates in the Annapurna range and flows through Nepal for a distance of 150 km, providing water for irrigation and supporting a variety of wildlife, including fish and otters.

Gandaki River: The Gandaki River is the second-longest river in Nepal, with a length of 640 km. It is also known as the Narayani River and originates from the Tibetan plateau before flowing through Nepal and joining the Ganges in India. The Gandaki River is famous for its rapids, and is a popular destination for rafting and kayaking. The river also supports a diverse range of flora and fauna, including the critically endangered gharial crocodile and the endangered freshwater Gangetic dolphin.