For a small country, Nepal has tremendous geographic diversity. It rises from less than 100 metres (328 ft) elevation in the tropical Terai—the northern rim of the Gangetic Plain, beyond the perpetual snow line to some 90 peaks over 7,000 metres (22,966 ft) including Earth's highest 8,848 metres (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 the rainshadow north of the Himalaya to as much as 5,500 millimetres (216.5 in) on windward slopes.
Along a south-to-north transect, Nepal can be divided into three belts: Terai, Hill and Mountain Regions. In the other direction it is divided into three major river systems, from east to west: Koshi,Gandaki/Narayani and Karnali (including the Mahakali/Sarda along the western border), all tributaries of the Ganges. The Ganges-Yarlung Zangbo/Brahmaputra watershed largely coincides with the Nepal-Tibet border, however several Ganges tributaries rise inside Tibet.
The Terai or Madhesh region begins at the Indian border and includes the southernmost part of the flat, intensively farmed Gangetic Plain called the Outer Terai. This is culturally close to northern India with the people speaking Awadhi, Bhojpuri, Tharu, and Maithili along with Nepali.
The Outer Terai ends at the first range of foothills called the Siwaliks or Churia. This range has a densely forested skirt of coarse alluvium called the bhabhar along its base. 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 it was dangerously infested with malaria. Nepal's rulers used it as a defensive frontier called the char kose jhadi (twelve kilometer forest)
Above the bhabhar belt, the Siwaliks 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 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. Hillside vegetation is limited to scrub forest and the area functions as a deserted buffer zone allowing the development of distinctive cultures in valleys and hills further north.
In several places beyond the Siwaliks there are dun valleys called Inner Terai (Bhitri Madesh) with productive soil. Among these are Dang and Deukhuri in western Nepal and the Rapti Valley (Chitwan) in central Nepal. Population in these valleys was historically limited by malaria and mainly of the Tharu ethnic group that has genetic resistance. Around 1960 DDT came into use tosuppress mosquitos and the way was open to settlement from the land-poor hills to the detriment of Tharus.
The Terai ends and the Hills begin at a higher range of foothills called the Mahabharat Range.
Situated south of the Mountain Region, the Hill Region (Pahar in Nepali) is mostly between 700 and 4,000 metres (2,297 and 13,123 ft) altitude. This region begins at the Mahabharat Range(Lesser Himalaya) where a fault system called the Main Boundary Thrust creates an escarpment 1,000 to 1,500 metres (3,281 to 4,921 ft) high, to a crest between 1,500 and 2,700 metres (4,921 and 8,858 ft). These steep southern slopes are nearly uninhabited, thus an effective buffer between languages and culture in the Terai and Hill regions. Northern slopes are gentler and moderately well populated.
North of this range, Nepali-speaking Hindus and Newar merchants who also speak Newari densely populate valleys suited to rice cultivation as high as 2,000 metres (6,562 ft). The increasingly urbanized Kathmandu and Pokhara valleys fall within this region. Indigenous janajati ethnic groups—natively speaking highly localized Tibeto-Burman languages and dialects—populate hillsides up to about 3,000 metres (9,843 ft). This group includes Magar and Kham Magar west of Pokhara, Gurung south of the Annapurnas, Tamang around the periphery of Kathmandu Valley and Raiand Limbu further east. Beyond microclimates suited to rice cultivation and proximity to water for irrigation, these cultivate maize, millet, barley and potatoes as staple crops. Temperate and subtropical fruits are grown as cash crops. Marijuana is grown and processed into Charas (hashish), but less than was produced before international pressure persuaded the government to outlaw it in 1976. There is increasing reliance on animal husbandry with elevation, using land above 3,000 metres (9,843 ft) for summer grazing and moving herds to lower elevations in winter. Outside the rice-growing lower valleys, hill populations suffer chronic food deficits. Many menfolk find employment in the Terai, in India or overseas to earn cash for imported grain. The Hill region ends dramatically where the main Himalayan Range abruptly rises thousands of meters. The Hil region of Nepals Mountains are importes grain.
The Mountain Region or Parbat abruptly rises into the zone of perpetual snow along the Main Central Thrust fault zone. South of this fault system, "hills" do not greatly exceed treeline at about 3,500 metres (11,483 ft). North of it the Himalayas rise as a virtual wall beyond the snowline at 5,000 to 5,500 metres (16,404 to 18,045 ft) to some 90 peaks over 7,000 metres (22,966 ft) and eight exceeding 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). Unlike the Mahabharats, the Himalaya are not continuous across Nepal. Instead there are about 25 subranges including the Kanchenjunga massif, Kumbu around Mt. Everest. Langtang north of Kathmandu, Annapurna north ofPokhara and Dhaulagiri further west, then Kanjiroba north of Jumla.
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 andKhumbu—cut between Himalayan subranges or lie north of them. Some of these valleys historically were more accessible fromTibet than Nepal and are populated by people with Tibetan affinities called Bhotiya or Bhutia including the famous 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 (14,764 ft) with summer encampments even higher. These peoples traditionally grazed yaks, grew cold-tolerant crops such as potatoes, barley, buckwheat and millet, and traded across the mountains, e.g., 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.
Nepal has tremendous variation in climate. Its latitude is about the same as that of Florida so Terai land up to 500 meters (1,640 ft) has a fully tropical climate, with a subtropical zone extending up to 1,200 meters (3,937 ft) which is the lower limit of frost in winter. Warm temperate climates prevail from 1,200 to 2,400 meters (3,937 to 7,874 ft) where snow occasionally falls. Then there is a cold zone to 3,600 meters (11,811 ft) (treeline), a subarctic or alpine zone to 4,400 meters (14,436 ft) and fully arctic climate above that. Precipitation generally decreases from east to west with increasing distance from the Bay of Bengal, source of the summer monsoon. Eastern Nepal gets about 2,500 mm (98.4 in) annually; the Kathmandu area about 1,400 mm (55.1 in) and western Nepal about 1,000 mm (39.4 in). This pattern is modified by adabiatic effects as rising air masses cool and drop their moisture content on windward slopes, then warm up as they descend so relative humidity drops. Annual precipitation reaches 5,500 mm (216.5 in) on windward slopes in the Annapurna Himalaya beyond a relatively low stretch of the Mahabharat Range. In rainshadows beyond the high mountains, annual precipitation drops as low as 160 mm (6.3 in), creating a cold semi-desert.
Furthermore the year is divided into a wet season from June to September—as summer warmth over Inner Asia creates a low pressure zone that draws in air from the Indian Ocean—and a dry season from October to June as cold temperatures in the vast interior creates a high pressure zone causing dry air to flow outward. April and May are months of intense water stress when cumulative effects of the long dry season are exacerbated by temperatures rising over 40 °C (104 °F). Seasonal drought intensifies in the Siwaliks hills consisting of poorly-consolidated, coarse, highly permeable sediments that do not retain water, so hillsides are covered with tropical scrub forest that is extremely drought-tolerant. In fact outside marsh and riparian zones, most of Nepal's native vegetation is adapted to withstand drought, although less so at higher elevations where cooler temperatures mean less water stress.
The monsoon is preceded by a buildup of thunderstorm activity in the hills that helps farmers irrigate rice seedbeds. Sustained rain on average arrives in early June as rising temperatures over Inner Asia creates a low pressure zone that draws in air from the Indian Ocean, but this can vary up to a month. Significant failure of monsoon rains historically meant drought and famine while above-normal rains still cause flooding and landslides with losses in human lives, farmland and buildings. The monsoon also complicates transportation with roads and trails washing out while unpaved roads and airstrips may become unusable and cloud cover reduces safety margins for aviation. Rains diminish in September and generally end by mid-October, ushering in generally cool, clear, and dry weather, as well as the most relaxed and jovial period in Nepal. By this time, the harvest is completed and people are in a festive mood. The two biggest and most important Hindu festivals—Dashain and Tihar (Dipawali)—arrive during this period, about one month apart. The postmonsoon season lasts until about December.
After the postmonsoon comes the winter monsoon, a strong northeasterly flow marked by occasional, short rainfalls in the lowlands and plains and snowfalls in the high-altitude areas. Precipitation varies from year to year but increases markedly with elevation. Adequate snowfall in the Himalaya is important for sufficient spring and summer meltwater for irrigation in the lower hills and valleys. At lower elevations, winter rainfall is needed for the success of winter crops such as wheat, barley and vegetables. In this season the Himalaya function as a barrier to cold air masses from Inner Asia, so southern Nepal and northern India have warmer winters than would otherwise be the case. April and May are dry and hot, especially below 1,200 meters (3,937 ft) where afternoon temperatures may exceed 40 °C (104 °F).
The dramatic changes in elevation along this transect result in a variety of biomes, from tropical savannas along the Indian border, to subtropical broadleaf and coniferous forests in the hills, totemperate broadleaf and coniferous forests on the slopes of the Himalaya, to montane grasslands and shrublands, and finally rock and ice at the highest elevations.
This corresponds to the Terai-Duar savanna and grasslands ecoregion.
Subtropical forests dominate the lower elevations of the Hill Region. They form a mosaic running east-west across Nepal, with Himalayan subtropical broadleaf forests between 500 and 1,000 metres (1,640 and 3,281 ft) and Himalayan subtropical pine forests between 1,000 and 2,000 metres (3,281 and 6,562 ft). At higher elevations, to 3,000 metres (9,843 ft), are found temperate broadleaf forests: eastern Himalayan broadleaf forests to the east of the Gandaki River and western Himalayan broadleaf forests to the west.
The native forests of the Mountain Region change from east to west as precipitation decreases. They can be broadly classified by their relation to the Gandaki River. From 3,000 to 4,000 metres (9,843 to 13,123 ft) are the eastern and western Himalayan subalpine conifer forests. To 5,500 metres (18,045 ft) are the eastern and western Himalayan alpine shrub and meadows.
Nepal has three categories of rivers. The largest systems -— from east to west Koshi, Gandaki/Narayani, Karnali/Goghra and Mahakali -- originate in multiple tributaries rising in or beyond the high Himalaya that maintain substantial flows from snowmelt through the hot, droughty spring before the summer monsoon. These tributaries cross the highest mountains in deep gorges, flow south through the Middle Hills, then join in candelabra-like configuration before crossing the Mahabharat Range and emerging onto the plains where they have deposited megafans exceeding 10,000 km2 (3,861 sq mi) area.
The Koshi is also called Sapta Koshi for its seven Himalayan tributaries in eastern Nepal: Indrawati, Sun Koshi, Tama Koshi, Dudh Koshi, Liku, Arun, and Tamur. The Arun rises in Tibet some 150 km. beyond Nepal's northern border. A tributary of the Sun Koshi, Bhote Koshi also rises in Tibet and is followed by the Arniko Highway connecting Kathmandu and Lhasa.
The Gandaki/Narayani has seven Himalayan tributaries in the center of the country: Daraudi, Seti Gandaki, Madi, Kali, Marsyandi, Budhi, and Trisuli also called Sapta Gandaki. The Kali Gandakirises on the edge of the Tibetan Plateau and flows through the semi-independent Kingdom of Mustang, then between the 8,000-meter (26,247 ft) Dhaulagiri and Annapurna ranges in the world's deepest valley. The Trisuli rises north of the international border inside Tibet. After the seven upper tributaries join, the river becomes the Narayani inside Nepal and is joined by the (East) Raptifrom Chitwan Valley. Crossing into India, its name changes to Gandak.
The Karnali drains western Nepal, with the Bheri and Seti as major tributaries. The upper Bheri drains Dolpo, a remote valley beyond the Dhaulagiri Himalaya with traditional Tibetan cultural affinities. The upper Karnali rises inside Tibet near sacred Lake Manasarovar and Mount Kailash. The area around these features is the hydrographic nexus of South Asia since it holds the sources of the Indus and its major tributary the Sutlej, the Karnali -- a Ganges tributary -- and the Yarlung Tsangpo/Brahmaputra. It is the center of the universe according to traditional cosmography. The Mahakali or Kali along the Nepal-India border on the west joins the Karnali in India, where the river is known as Goghra or Ghaghara.
Second category rivers rise in the Middle Hills and Mahabharat Range, from east to west the Mechi, Kankai and Kamala south of the Kosi; the Bagmati that drains Kathmandu Valley between the Kosi and Gandaki systems, then the West Rapti and the Babai between the Gandaki and Karnali systems. Without glacial sources, annual flow regimes in these rivers are more variable although limited flow persists through the dry season.
Third category rivers rise in the outermost Siwalik foothills and are mostly seasonal.
None of these river systems support significant commercial navigation. Instead, deep gorges create obstacles to establishing transport and communication networks and de-fragmenting the economy. Foot-trails are still primary transportation routes in many hill districts.
All three categories are capable of causing serious floods, for example the West Rapti in the second category is calledGorakhpur's Sorrow for its history of urban flooding. Koshi River in the first category caused a major flood in August 2008 in Bihar state, India after breaking through a poorly-maintained embankment just inside Nepal.
Since uplift and erosion are more or less in equilibrium in the Himalaya, rapid uplift is balanced by annual increments of cubic kilometers of sediments washing down from the mountains, then on the plains settling out of suspension on vastalluvial fans or inland deltas over which rivers meander and change course at least every few decades, causing some experts to question whether manmade embankments can contain the problem of flooding. Traditional Mithila culture along the lower Koshi in Nepal and Bihar celebrated the river as the giver of life for its fertile alluvial soil, yet also the taker of life through its catastrophic floods.
Another approach would be to build large dams—in gorges crossing the Mahabharat Range or further upstream—with storage capacities measured in cubic kilometers to capture high flows during the monsoon when there is usually enough rainfall on the plains if not flooding, then releasing water for hydroelectric generation and irrigation especially during the hot and dry pre-monsoon "summer". Nepal would appear to have unusual potential given its average annual 150 cm. of precipitation and thousands of meters of relief between mountains and plains, but there has only been limited development of this potential for example on the Kali Gandaki north of Tansen.
Building dams in Nepal is controversial for several reasons. First, the region is seismically active. Dam failures caused by earthquakes could cause tremendous death and destruction downstream, particularly on the densely populated Gangetic Plain. Second, global warming has led to the formation of glacial lakes dammed by unstable moraines. Sudden failures of these moraines can cause floods with cascading failures of manmade structures downstream. Third, sedimentation rates in the Himalaya are extremely high, leading to rapid loss of storage capacity as sediments accumulate behind dams. Fourth, there are complicated questions of cross-border equity in how India and Nepal would share costs and benefits that have proven difficult to resolve in the context of frequent acrimony between the two countries.
As Nepal builds barrages in the Terai to divert more water for irrigation during the dry season preceeding the summer monsoon, there is less for downstream users in India's Bihar and Uttar Pradesh states. The best solution could be building large upstream reservoirs in the Middle Hills to capture and store surplus flows during summer months as well as providing downstram flood control benefits into Bangladesh and India. Then water sharing agreements could allocate a portion of the stored water to be left to flow into India during the following dry season.
Area
- Total: 147,181 km²
- Land: 143,181 km²
- Water: 4,000 km²
- Area - comparative
- Roughly 1⅔ Tasmania's size
- Roughly twice New Brunswick's size
- Slightly less than twice Scotland's size
- Slightly larger than Arkansas
- Coastline
- 0 km (landlocked)
- Maritime claims
- None (landlocked)
- Elevation extremes
- Lowest point: Kechana Kalan 70 m
- Highest point: Sagarmatha (Mount Everest) 8,848 m
- Total: 2,926 km
- Border countries: China 1,236 km, India 1,690 km
While India and Nepal have an open border with no restrictions on movement of their citizens on either side, there are 22 checkpoints for trade purposes. These are listed in counterclockwise order, east to west. The six in italics are also used for entry/exit by third country nationals.
- Pashupatinagar / Sukhiapokhri
- Kakarbhitta / Naxalbari (Panitanki)
- Bhadrapur / Galgalia
- Biratnagar / Jogbani
- Setobandha / Bhimnagar
- Rajbiraj / Kunauli
- Siraha / Jayanagar
- Jaleswar / Sursand
- Malangawa / Sonbarsa
- Gaur / Bairgania
- Birganj / Raxaul
- Siddharthanagar (Bhairahawa) / Nautanwa
- Taulihawa / Khunwa
- Krishnanagar / Barhni
- Koilabas / Jarwa
- Nepalgunj / Rupaidiha
- Rajapur / Katerniyaghat
- Prithivipur / Sati (Kailali) / Tikonia
- Dhangadhi / Gauriphanta
- Mahendranagar / Banbasa
- Mahakali / Jhulaghat (Pithoragarh)
- Darchula/Dharchula.
- Natural resources
- Quartz, water, timber, hydropower, scenic beauty, small deposits of lignite, copper, cobalt, iron ore
- Land use
- Arable land: 21.68%
- Permanent crops: 0.64%
- Other: 77.68% (2001)
- Irrigated land
- 11,350 km² (1998 established)
25.4% of Nepal's land area, or about 36,360 km2 (14,039 sq mi) is covered with forest according to FAO figures from 2005. FAO estimates that around 9.6% of Nepal's forest cover consists ofprimary forest which is relatively intact. About 12.1% Nepal's forest is classified as protected while about 21.4% is conserved according to FAO. About 5.1% Nepal's forests are classified asproduction forest. Between 2000-2005, Nepal lost about 2,640 km2 (1,019 sq mi) of forest. Nepal's 2000-2005 total deforestation rate was about 1.4% per year meaning it lost an average of 530 km2 (205 sq mi) of forest annually. Nepal's total deforestation rate from 1990-2000 was 920 km2 (355 sq mi) or 2.1% per year. The 2000-2005 true deforestation rate in Nepal, defined as the loss of primary forest, is -0.4% or 70 km2 (27 sq mi) per year.
Deforestation is driven by multiple processes. In the hills, conversion of forests to agricultural land—even on steep hillsides via terracing—is historically important, but has lessened in recent decades due to a shortage of remaining suitable terrain in the hills while mosquito suppression having opened formerly malarial land for settlement in the Terai. As a result, forest land in the Terai is being cleared by settlers.
In the hills, greater contemporary impacts involve degradation of forests rather than outright clearing. Degradation is caused by harvesting firewood, and to a lesser extent wood for traditional architecture. These harvests are often carried to unsustainable levels. Trees are also severely damaged by intensive harvesting of leaves as fodder, especially in the driest months preceding the summer monsoon. Households typically keep at least one cow or buffalo for milk production and may also keep oxen for agricultural labor. In addition goats are herded as the main source of meat that is culturally acceptable to upper-caste Hindus.
- FAO Forestry Department Nepal Country Page
- Ministry of Forests and Soil Conservation Nepal
- Forestry Information in Nepal
- Natural hazards
- Earthquakes, severe thunderstorms, flooding, landslides, drought, and famine depending on the timing, intensity, and duration of the summer monsoons
- Environment - current issues
- Deforestation (overuse of wood for fuel and lack of alternatives); contaminated water (with human and animal wastes, agricultural runoff, and industrial effluents); wildlife conservation; vehicular emissions; High arsenic and microbiological levels in groundwater
- Environment - international agreements
- Party to: Biodiversity, Climate Change, Desertification, Endangered Species, Hazardous Wastes, Law of the Sea, Nuclear Test Ban, Ozone Layer Protection, Tropical Timber 83, Tropical Timber 94, Wetlands
- Signed, but not ratified: Marine Life Conservation
- Existing and proposed dams, barrages and canals for flood control, irrigation and hydroelectric generation
- Geography - note
- Landlocked; strategic location between China and India; contains eight of world's 10 highest peaks