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Geography of Nepal

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Through Nepal, China and Bangladesh

Nepal is landlocked by China's Tibet Autonomous Region to the north and India on the other three sides. West Bengal's narrow Siliguri Corridor separates Nepal from Bangladesh. To the east are Bhutan and India.

Nepal has a very high degree of geographic diversity and can be divided into three main regions: Terai, Hilly, and Himal. The Terai region, covering 17% of Nepal's area, is a lowland region with some hill ranges and is culturally more similar to parts of India. The Hilly region, encompassing 68% of the country's area, consists of mountainous terrain without snow and is inhabited by various indigenous ethnic groups. The Himal region, covering 15% of Nepal's area, contains snow and is home to several high mountain ranges, including Mount Everest, the world's highest peak. Nepal, with elevations ranging from less than 100 metres to over 8,000 metres, has eight climate zones from tropical to perpetual snow. The majority of the country's population resides in the tropical and subtropical climate zones. The tropical zone, below 1,000 metres, experiences frost less than once per decade and is suitable for growing various fruits and crops. The subtropical climate zone, from 1,000 to 2,000 metres, is the most prevalent and suitable for growing rice, maize, millet, wheat, and other crops. The temperate climate zone, from 2,000 to 3,000 metres, occupies 12% of Nepal's land area and is suitable for cold-tolerant crops. The subalpine, alpine, and nival zones have progressively fewer human settlements and agricultural activities.

Seasons are divided into a wet season from June to September and a dry season from October to June. The summer monsoon can cause flooding and landslides, while the winter monsoon is marked by occasional rainfall and snowfall. The diverse elevation results in various biomes, including tropical savannahs, subtropical and temperate forests, montane grasslands, and shrublands.

Nepal has three categories of rivers: the largest systems (Koshi, Gandaki/Narayani, Karnali/Goghra, and Mahakali), second category rivers (rising in the Middle Hills and Lower Himalayan Range), and third category rivers (rising in the outermost Siwalik foothills and mostly seasonal). These rivers can cause serious floods and pose challenges to transportation and communication networks. River management involves addressing flooding, sedimentation, and sustainable water sources for irrigation. Building dams in Nepal is controversial due to seismic activity, glacial lake formation, sedimentation rates, and cross-border equity issues between India and Nepal.

Nepal's land cover is dominated by forests, which cover 39.09% of the country's total geographical area, followed by agriculture areas at 29.83%. The hill region constitutes the largest portion of Nepal, with significant cultivated lands and natural vegetation. Forests in Nepal face deforestation due to over-harvesting of firewood, illegal logging, clearing for agriculture, and infrastructure expansion. As of 2010, 64.8% of the forested area in Nepal is covered by core forests of more than 500 ha in size. Deforestation and degradation are driven by multiple processes, including firewood harvesting, construction, urban expansion, and illegal logging.

Nepal has consistently been ranked as one of the most polluted countries in the world.

Landform regions

For a country of its size, Nepal has tremendous geographic diversity. It rises from as low as 59 metres (194 ft) elevation in the tropical Terai—the northern rim of the Gangetic Plain, through beyond the perpetual snow line to 90 peaks over 7,000 metres (22,966 ft) including Earth's highest (8,848-metre (29,029 ft) Mount Everest or Sagarmatha). In addition to the continuum from tropical warmth to cold comparable to polar regions, average annual precipitation varies from as little as 160 millimetres (6.3 in) in its narrow proportion of the rainshadow north of the Himalayas to as much as 5,500 millimetres (216.5 in) on windward slopes, the maximum mainly resting on the magnitude of the South Asian monsoon.

Forming south-to-north transects, Nepal can be divided into three belts: Terai, Pahad and Himal. In the other direction, it is divided into three major river systems, east to west: Koshi, Gandaki/Narayani and Karnali (including the Mahakali along the western border), all tributaries of the Ganges river. The Ganges-Yarlung Zangbo/Brahmaputra watershed largely coincides with the Nepal-Tibet border, save for certain tributaries rising beyond it.

Himal

Himal Region is a mountainous region containing snow. The Mountain Region begins where high ridges (Nepali: लेक; lekh) begin substantially rising above 3,000 metres (10,000 ft) into the subalpine and alpine zone which are mainly used for seasonal pasturage. By geographical view, it covers 15% of the total area of Nepal. A few tens kilometres further north the high Himalaya abruptly rise along the Main Central Thrust fault zone above the snow line at 5,000 to 5,500 metres (16,400 to 18,000 ft). Some 90 of Nepal's peaks exceed 7,000 metres (23,000 ft) and eight exceed 8,000 metres (26,247 ft) including Mount Everest at 8,848 metres (29,029 ft) and Kanchenjunga at 8,598 metres (28,209 ft).

There are some 20 subranges including the Kanchenjunga massif along with the Mahalangur Himal around Mount Everest. Langtang north of Kathmandu, Annapurna and Manaslu north of Pokhara, then Dhaulagiri further west with Kanjiroba north of Jumla and finally Gurans Himal in the far west.

Trans-Himalayan

The main watershed between the Brahmaputra (called Yarlung Tsangpo in Tibet) and the Ganges system (including all of Nepal) actually lies north of the highest ranges. Alpine, often semi-arid valleys—including Humla, Jumla, Dolpo, Mustang, Manang and Khumbu—cut between Himalayan sub ranges or lie north of them.

Some of these valleys historically were more accessible from Tibet than Nepal and are populated by people with Tibetan affinities called Bhotiya or Bhutia including the Sherpas in Kumbu valley near Mount Everest. With Chinese cultural hegemony in Tibet itself, these valleys have become repositories of traditional ways. Valleys with better access from the hill regions to the south are culturally linked to Nepal as well as Tibet, notably the Kali Gandaki Gorge where Thakali culture shows influences in both directions.

Permanent villages in the mountain region stand as high as 4,500 metres (15,000 ft) with summer encampments even higher. Bhotiyas graze yaks, grow cold-tolerant crops such as potatoes, barley, buckwheat and millet. They traditionally traded across the mountains, including Tibetan salt for rice from lowlands in Nepal and India. Since trade was restricted in the 1950s they have found work as high altitude porters, guides, cooks and other accessories to tourism and alpinism.

Hilly

Hilly Region is a mountain region which does not generally contain snow. It is situated to the south of the Himal Region (the snowy mountain region). This region begins at the Lower Himalayan Range, where a fault system called the Main Boundary Thrust creates an escarpment 1,000 to 1,500 metres (3,000 to 5,000 ft) high, to a crest between 1,500 and 2,700 metres (5,000 and 9,000 ft). It covers 68% of the total area of Nepal.

These steep southern slopes are nearly uninhabited, thus an effective buffer between languages and culture in the Terai and Hilly. Paharis mainly populate river and stream bottoms that enable rice cultivation and are warm enough for winter/spring crops of wheat and potato. The increasingly urbanised Kathmandu and Pokhara valleys fall within the Hill region. Newars are an indigenous ethnic group with their own Tibeto-Burman language. The Newar were originally indigenous to the Kathmandu valley but have spread into Pokhara and other towns alongside urbanised Pahari.

Other indigenous Janajati ethnic groups -— natively speaking highly localised Tibeto-Burman languages and dialects -— populate hillsides up to about 2,500 metres (8,000 ft). This group includes Magar and Kham Magar west of Pokhara, Gurung south of the Annapurnas, Tamang around the periphery of Kathmandu Valley and Rai, Koinch Sunuwar and Limbu further east. Temperate and subtropical fruits are grown as cash crops. Marijuana was grown and processed into Charas (hashish) until international pressure persuaded the government to outlaw it in 1976. There is increasing reliance on animal husbandry with elevation, using land above 2,000 metres (7,000 ft) for summer grazing and moving herds to lower elevations in winter. Grain production has not kept pace with population growth at elevations above 1,000 metres (3,300 ft) where colder temperatures inhibit double cropping. Food deficits drive emigration out of the Pahad in search of employment.

The Hilly ends where ridges begin substantially rising out of the temperate climate zone into subalpine zone above 3,000 metres (10,000 ft).

Terai

Terai is a low land region containing some hill ranges. Looking out for its coverage, it covers 17% of the total area of Nepal. The Terai (also spelt Tarai) region begins at the Indian border and includes the southernmost part of the flat, intensively farmed Gangetic Plain called the Outer Terai. By the 19th century, timber and other resources were being exported to India. Industrialisation based on agricultural products such as jute began in the 1930s and infrastructure such as roadways, railways and electricity were extended across the border before it reached Nepal's Pahad region.

The Outer Terai is culturally more similar to adjacent parts of India's Bihar and Uttar Pradesh than to the Pahad of Nepal. Nepali is taught in schools and often spoken in government offices, however, the local population mostly uses Maithali, Bhojpuri and Tharu languages.

The Outer Terai ends at the base of the first range of foothills called the Chure Hills or Churia. This range has a densely forested skirt of coarse alluvium called the Bhabar. Below the Bhabhar, finer, less permeable sediments force groundwater to the surface in a zone of springs and marshes. In Persian, terai refers to wet or marshy ground. Before the use of DDT this was dangerously malarial. Nepal's rulers used this for a defensive frontier called the char kose jhadi (four kos forest, one kos equaling about three kilometres or two miles).

Above the Bhabar belt, the Chure Hills rise to about 700 metres (2,297 ft) with peaks as high as 1,000 metres (3,281 ft), steeper on their southern flanks because of faults are known as the Main Frontal Thrust. This range is composed of poorly consolidated, coarse sediments that do not retain water or support soil development so there is virtually no agricultural potential and sparse population.

In several places beyond the Chure, there are dūn valleys called Inner Terai. These valleys have productive soil but were dangerously malarial except to indigenous Tharu people who had genetic resistance. In the mid-1950s DDT came into use to suppress mosquitos and the way was open to settlement from the land-poor hills, to the detriment of the Tharu.

The Terai ends and the Pahad begin at a higher range of foothills called the Lower Himalayan Range.

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