Inner Terai Valleys of Nepal

Main article: Madhesh

The phrase Inner Terai Valleys or Bhitri tarai (भित्री तराइ) refers to various elongated valleys in Nepal lying between the southernmost Himalayan foothills, the ~600 metre Chure or Siwalak Range and the 2-3,000 metre high Mahabharat Range further north, whereas Outer Terai refers to plains extending south of the Chure/Sivalik Hills to the border with India.

Major examples in Nepal include the Chitwan Valley southwest of Kathmandu and the parallel Dang and Deukhuri Valleys in western Nepal.

Climate & Economy

Nepal topography.

In the past the inner and outer Terai regions contained thick, malaria-infested forests, forming a frontier between Nepal and the British Raj (1858-1947) in India. The indigenous people, Tharu had a degree of inherited resistance to malaria and populated these areas. After an malaria eradication campaign people migrated to the Terai from the mountains and from neighbouring India. Today more than half the population are migrants, and many towns have developed.

The Inner and Outer Tarai's are Nepal's richest economic regions, with fertile farms and forests. The Tarai is still Nepal's main source of food, and a migration destination for landless hill peasants. Tarai residents have more available agricultural land than other Nepalese because of the area's generally flat terrain, which is drained and nourished by several rivers. As well, the Terai has the largest commercially exploitable forests.

Environmental Issues

The Inner Terai valleys are home to a rich and diverse ecosystem. Since the early 1990s, however, the forests have been increasingly destroyed because of growing demands for timber and agricultural land This has led to concerns about the risk of losing many rare plant species.

The valleys also play an important role in mitigating the severity of floods in the Gangetic plains. In times of heavy rainfall, the forests absorb the water. In times of heavy run-off from the Himalayan watershed, the rivers spread out from their banks, flooding the forest. Later, the forests gradually release the water into the rivers that feed the Ganges. Forest removal reduces or eliminates this buffering effect.

Kamala Valley

Sagarmatha zone: Udayapur district in green

26°47′N 86°41′E

The Kamala Valley is in the Udayapur district in the south-east of Nepal. (Sketch map). About 30 km long and between 2 km and 4 km wide, it is drained by the Triyuga river, which runs east to feed the great Koshi River. The valley lies between the Mahabharat Lekh (Range) to the north and the the Churia or Sivalik Hills to the south, with an average elevation of about 430 meters.

Traditionally, the valley was primarily inhabited by the Dhanwar or Danuwar people, but there is a fast-growing population of migrants from the Nepali hills and from India. Towns include Gaighat (or Triyuga) and Katari.

Marin Khola Valley

Janakpur zone: Sindhuli district is green band in center

27°13′11″N 85°55′12″E

Marin Khola Valley is one of the smaller Inner Terai Valleys, in the central south region, Sindhulī Garhi district. (Sketch Map) The Kokhajor Khola, the Marin Khola and the Kyan Khola rivers join in the valley to form the Kamala river, a major tributary to the Bhurengi..

The main town is Kamalamai.

The Indian government is concerned about flooding from the Kamala river, and is funding engineering projects in an attempt to control the situation.

The Marin Khola valley is one of the areas of Nepal inhabited by Hayu people, who also live in the valleys of the Rosi Khola and the Sun Kosi north of the Mahabharat range.

Chitwan Valley

Natayani zone: the Chitwan district is yellow area to the west

Main article: Chitwan Valley

27°41′N 84°26′E

The Chitwan Valley is in central Nepal in the Narayani Zone. It is 150 km long and roughly 30-48 km wide, the largest of the inner Terai valleys. (Sketch Map) The cities of Bharatpur, Hetauda, and Ratnanagar are in the valley.

The Narayni and East Rapti rivers join in the valley. The Naryani is the main river and life line of the Chitwan Valley, flowing from the Himalayan Glaciers with tributaries Kaligandaki, Trishuli, Seti, Madi, Marshangdi, Budhi Gandaki and Draudi. The Naryani is also known as the Gandaki River in India. The Rapti river flows from the Mahabharat Lekh (range) and enters the Chitwan valley from Hetuda, joining the Naryani west of the Meghauli.

The Chitwan National Park is one of the most important sub-tropical parks on the Indian subcontinent with good populations of the endangered Royal Bengal tiger, Greater One-horned rhinos, Gangetic dolphin (Platanista gangetica), Wild Asian elephant, Gaur, Golden Monitor lizard and Gharial crocodile. In 1963 the southern two-thirds of the park were declared a Rhino Sanctuary, with a moratorium on hunting and the relocation of 22,000 people from the Chitwan valley. Since then, wildlife populations and ecosystems have been rebounding in this area. In 1973 Chitwan became Nepal’s first National Park. The unique ecosystems prompted UNESCO to declare the park a World Heritage site in 1984.

Surkhet Valley

Bheri Zone districts. Surkhet is the purple band in the center

28°36′N 81°38′E

The Surkhet Valley is in the mid-west of Nepal, in the Surkhet district. (Sketch map). It is drained by the Bheri River. Birendranagar is a population center in the valley.

Deukhuri and Dang Valleys

Rapti zone: Dang Deokhuri district in south west

26°51′N 85°35′E

The parallel Deukhuri and Dang Valleys are in the Rapti zone of mid-western Nepal, in the Dang Deokhuri district (Sketch map).

• The Deukhuri Valley is drained by the West Rapti river.

• The Dang Valley is drained by the Babai river.

This district includes the Royal Bardia National Park, east of the Karnali River. The park is the largest and most undisturbed wilderness area in the Terai. About 70% of the park is covered with forest with the balance a mixture of grassland, savannah and riverine forest.

The cities of Tribhuvannagar and Tulsipur are in the Dang valley.

Jogbudha Valley

The Jogbudha Valley is in the far west of Nepal, in the Dadeldhura district. It is drained by the Mahakali river.