Inner Terai Valleys of Nepal

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{{main|Geology of the Himalaya}}

{{Unreferenced section|date=December 2014}}

The Inner Terai valleys lie between the Sivalik Hills and Mahabharat Range. They hold flat plains with winding rivers that shift their courses from time to time, running northwest or southeast along the axis of the Sivalik Hills.

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The Terai has a humid, subtropical climate. The mean annual rainfall at the Rampur weatherstation in Chitwan was {{convert|2214|mm|in|abbr=on}} between 1995 and 2006. More than 80% of the total annual rainfall occurs during the monsoon season from June to September. Average temperatures ranged from {{convert|8.08|C|F|abbr=on}} in January to {{convert|34.91|C|F|abbr=on}} in June.Department of Hydrology and Meteorology (2006). Climatological Records of Nepal (Several Volumes), Babarmahal, Kathmandu.

In the past, the inner and outer Terai were a formidable barrier between Nepal and potential invaders from India because marshes and forests were infested by anopheline mosquitos that transmitted virulent strains of malaria, especially during the hot spring and rainy summer monsoon.

Until the mid 18th century, the Terai was divided into several smaller kingdoms, and the forests were little disturbed.Gautam, A. P., Shivakoti, G. P., & Webb, E. L. (2004). A review of forest policies, institutions, and changes in the resource condition in Nepal. International Forestry Review 6 (2): 136–148. After the unification of Nepal in the late 1760s, the rulers granted large areas of fertiIe land and forest resources to members of the royal family, officials, priests and selected groups of the society. The beneficiaries of these grants had the right to collect revenues from cultivated land and forest products. They appointed tax collectors who were also responsible for reclamation of land and establishment of settlements.Regmi, R. R. (1994). Deforestation and Rural Society in the Nepalese Terai. Occasional Papers in Sociology and Anthropology 4: 72–89.

In the late 1920s, the Rana rulers ordered the clearing of forests and extraction of timber for export to India in order to collect revenues. Cleared areas were subsequently used for agriculture.

Tharu people have been living in the Terai for many centuries, and reputedly had an innate resistance to malaria.{{Cite journal |author=Terrenato, L., Shrestha, S., Dixit, K.A., Luzzatto, L., Modiano, G., Morpurgo, G., Arese, P. |title=Decreased malaria morbidity in the Tharu people compared to sympatric populations in Nepal |journal=Annals of Tropical Medicine and Parasitology |volume=82 |issue=1 |year=1988 |pages=1–11 |pmid=3041928 |doi=10.1080/00034983.1988.11812202}}

After malaria was eradicated using DDT in the mid-1950s, people from the hills migrated to the Terai. Timber export continued to 1969. In 1970, the king granted land to loyal ex-army personnel in the districts of Jhapa, Sunsari, Rupandehi and Banke, where seven colonies were developed for resettling about 7,000 people. They acquired property rights over uncultivated forest and waste land, thus accelerating the deforestation process in the Terai.

The well-meaning malaria eradication campaign has had unexpected consequences by opening up the Terai region to human settlement. 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.{{Cite web |url=http://www.forestrynepal.org/publications/reports/3778 |title=Regional Workshop on Issues, Challenges and Opportunities for Forest Management of Terai, Inner Terai and Churia in Nepal |access-date=2008-10-10 |archive-date=2008-12-01 |archive-url=https://web.archive.org/web/20081201162825/http://www.forestrynepal.org/publications/reports/3778 |url-status=dead}}{{Cite web |url=http://www.forestsmonitor.org/en/reports/549391/549398 |title=Forests Monitor: The Terai Forests |access-date=2008-10-10 |archive-date=2017-06-29 |archive-url=https://web.archive.org/web/20170629120509/http://www.forestsmonitor.org/en/reports/549391/549398 |url-status=dead}}

This has led to concerns about the risk of losing many rare plants.{{Cite web |url=http://www.mountainfund.org/html_site/research/orchids_in_the_churiya_hills_and_their_survival_in_nepal.pdf |title=Orchids in the Churiya Hills and their survival in Nepal |access-date=2008-10-10 |archive-url=https://web.archive.org/web/20081219183024/http://www.mountainfund.org/html_site/research/orchids_in_the_churiya_hills_and_their_survival_in_nepal.pdf |archive-date=2008-12-19 |url-status=dead}}[http://www.nepjol.info/index.php/ON/article/viewFile/506/506 An Overview of Floral Diversity in Wetlands of Terai Region of Nepal: M. Siwakoti, Natural History Museum, Tribhuvan University Swayambhu, Nepal]

The valleys also mitigate the severity of floods on the Gangetic plains. During heavy rainfall forests absorb water. During floods, rivers overflow their banks and flood adjacent forests. Later the forests gradually release water back into the rivers. Deforestation reduces this buffering effect. It also accelerates soil erosion, causing downstream rivers to silt up and overflow their banks.{{Cite web |url=http://home.iitk.ac.in/~rsinha/Vik_syn.htm |title=Fluvial geomorphological analysis with special reference to flood hazard, Baghmati River basin, north Bihar, India |access-date=2008-10-14 |archive-url=https://web.archive.org/web/20080922005356/http://home.iitk.ac.in/~rsinha/Vik_syn.htm |archive-date=2008-09-22 |url-status=dead}} The frequency and severity of flooding in the Gangetic plain and Bangladesh has steadily increased in recent years. Deforestation of the Terai appears to be one of the major causes.{{Cite web |url=http://www.cs.albany.edu/~amit/BanglaFloods.txt |title=Recent floods in Bangladesh: Possible causes and solutions |access-date=2008-10-14 |archive-url=https://archive.today/19970724184800/http://www.cs.albany.edu/~amit/BanglaFloods.txt |archive-date=1997-07-24 |url-status=dead}} The Indian and Nepalese governments are cooperating in measures including construction of barrages and dams in the Terai, such as the Koshi Barrage.{{Cite web |url=http://wrmin.nic.in/writereaddata/linkimages/flood%20and%20centrally%20sponsered%20schemes2735345443.pdf |title=Indian Ministry of Water Resources – Flood and centrally sponsored schemes (c) |access-date=2008-10-13 |archive-url=https://web.archive.org/web/20081219184550/http://wrmin.nic.in/writereaddata/linkimages/flood%20and%20centrally%20sponsered%20schemes2735345443.pdf |archive-date=2008-12-19 |url-status=dead}} However, these efforts may have mixed results. They contain floodwater in the short term, but may increase the problem in the longer term by reducing water velocity in the rivers downstream, and thus accelerating silting and reducing the drainage capacity of the rivers.{{Cite web |url=http://www.hewett.norfolk.sch.uk/CURRIC/NEWGEOG/floods/floodreport.htm |title=Causes, Effects and responses to flooding: The UK and Bangladesh |access-date=2008-10-14 |archive-url=https://web.archive.org/web/20090121193126/http://www.hewett.norfolk.sch.uk/curric/NEWGEOG/floods/floodreport.htm |archive-date=2009-01-21 |url-status=dead}}

The major Inner Terai Valleys are listed from west to east.

Click on the terrain and satellite imagery links to see vegetation, rivers, topography, roads and towns.

Markers at valleys Jogbudha (J), Surkhet (S), Dang (A) and Deukhuri (E) [https://maps.google.com/maps/api/staticmap?center%3D28.4011,81.4196&zoom%3D8&size%3D640x400&maptype%3Dterrain&markers%3Dcolor:blue%7Clabel:J%7C29.1354,80.3362&markers%3Dcolor:blue%7Clabel:S%7C28.5791,81.6219&markers%3Dcolor:blue%7Clabel:A%7C28.0659,82.3096&markers%3Dcolor:blue%7Clabel:E%7C27.8330,82.5458&sensor%3Dfalse terrain]

[https://maps.google.com/maps/api/staticmap?center%3D28.4011,81.4196&zoom%3D8&size%3D640x400&maptype%3Dsatellite&markers%3Dcolor:blue%7Clabel:J%7C29.1354,80.3362&markers%3Dcolor:blue%7Clabel:S%7C28.5791,81.6219&markers%3Dcolor:blue%7Clabel:A%7C28.0659,82.3096&markers%3Dcolor:blue%7Clabel:E%7C27.8330,82.5458&sensor%3Dfalse satellite]

Image:NepalSurkhetDistrictmap.png

The Surkhet Valley is situated in the Surkhet district, mid-western Nepal. The valley is about {{cvt|700|m|ft}} above sea level, forming an ellipse about {{cvt|9|km}} east-west by {{cvt|6|km}} north-south. It is drained by the Bheri River, a tributary of the Karnali.{{cite thesis |author=Yadav, S. K. |year=2002 |title=Hydrological Analysis for Bheri-Babai Hydropower Project Nepal |type=MSc. Thesis |publisher=The Norwegian University For Science and Technology |place=Trondheim |url=http://www.ub.uib.no/elpub/NORAD/2002/ntnu/thesis01.pdf |access-date=2008-10-11 |archive-date=2008-12-19 |archive-url=https://web.archive.org/web/20081219183024/http://www.ub.uib.no/elpub/NORAD/2002/ntnu/thesis01.pdf |url-status=dead }}

The district is the homeland of the Raji people.{{cite journal |author=Thapa L. B., Dhakal T. M., Chaudhary R., Thapa H. | year=2014 |title=Medicinal Plants Used by Raji Ethnic Tribe of Nepal in Treatment of Gastrointestinal Disorders |journal=Our Nature |volume=11 |issue=2 |pages=177–186 |doi=10.3126/on.v11i2.9645 |doi-access=free}} Tharu people from Dang settled in the valley since at least the 19th century.{{cite journal |author=Krauskopff, G. |year=1995 |title=The Anthropology of the Tharus: An Annotated Bibliography |journal=Kailash |volume=17 |issue=3&4 |pages=185–213 |url=http://himalaya.socanth.cam.ac.uk/collections/journals/kailash/pdf/kailash_17_0304_05.pdf}}

Imagery of Surkhet (S):

[https://maps.google.com/maps/api/staticmap?center%3D28.35,81.6219&zoom%3D10&size%3D640x640&maptype%3Dterrain&markers%3Dcolor:blue%7Clabel:S%7C28.5791,81.6219&sensor%3Dfalse terrain]

[https://maps.google.com/maps/api/staticmap?center%3D28.5791,81.6219&zoom%3D12&size%3D640x640&maptype%3Dsatellite&sensor%3Dfalse satellite]

File:NepalDangDistrictmap.png

Both valleys are located in the Dang Deukhuri District of the Rapti Zone in mid-western Nepal.

The Dang Valley lies between the Mahabharat Range in the north and the Churia Range in the south.Sharmai, D. R. (1988). Archaeological Remains of the Dang Valley. Ancient Nepal 88: 8–15. It forms a

nearly {{cvt|1000|km2}} plain within a local drainage basin of less than {{cvt|3000|km2}}. It is drained by the Babai River, and is one of the largest Inner Terai valleys.{{cite journal | author = Mugnier J. L., Leturmy P., Mascle G., Huyghe P., Chalaron E., Vidal G., Delcaillau B. |year=1999 |title=The Siwaliks of western Nepal: I. Geometry and kinematics |journal=Journal of Asian Earth Sciences |volume=17 |issue=5 |pages=629–642 |doi=10.1016/s1367-9120(99)00038-3 |bibcode=1999JAESc..17..629M}}

The Deukhuri Valley is southeast of the Dang Valley and extends about {{cvt|60|km}} in WNW-ESE direction with a maximum width of {{cvt|20|km}}.Kimura, K. (1998). Geomorphic Development of the Deukhuri Dun, Nepal Sub-Himalaya. The science reports of the Tohoku University, 7th series. It forms a nearly {{cvt|600|km2}} plain within a drainage basin of {{cvt|6100|km2}}. The valley is drained by the West Rapti River.

The Mahendra Highway passes through the Deukhuri Valley. Both valleys are settled by Tharu people.

Imagery of Dang (A) and Deukhuri (E):

[https://maps.google.com/maps/api/staticmap?center%3D27.9471,82.4538&zoom%3D10&size%3D640x480&maptype%3Dterrain&markers%3Dcolor:blue%7Clabel:A%7C28.0659,82.3096&markers%3Dcolor:blue%7Clabel:E%7C27.8330,82.5458&sensor%3Dfalse terrain] [https://maps.google.com/maps/api/staticmap?center%3D27.9471,82.4538&zoom%3D10&size%3D640x480&maptype%3Dsatellite&markers%3Dcolor:blue%7Clabel:A%7C28.0659,82.3096&markers%3Dcolor:blue%7Clabel:E%7C27.8330,82.5458&sensor%3Dfalse satellite]

The Chitwan Valley, the biggest valley in Nepal, encompasses the districts of Makwanpur, Chitwan and Nawalpur of central Nepal. The Chitwan Valley lies south-west of the Kathmandu valley and it has 600 square miles in area. After the re-structuring of the country in 2015, two districts of this valley, namely, Makwanpur and Chitwan lies in Bagmati Province and Nawalpur district lies in Gandaki Province. It is {{convert|150|km|mi|abbr=on}} long and roughly {{convert|30-48|km|mi|abbr=on}} wide. The cities of Bharatpur, Ratnanagar, Hetauda and Kawasoti are in the valley. It is drained by the Rapti River flowing from the Mahabharat Range near Hetauda, then west down the valley to join the bigger Narayani River west of Meghauli situated within the valley.

Imagery of Chitwan (C):

[https://maps.google.com/maps/api/staticmap?center%3D27.45,84.44&zoom%3D9&size%3D640x480&maptype%3Dterrain&markers%3Dcolor:blue%7Clabel:C%7C27.57,84.49&sensor%3Dfalse terrain]

[https://maps.google.com/maps/api/staticmap?center%3D27.59,84.42&zoom%3D10&size%3D640x350&maptype%3Dsatellite&sensor%3Dfalse satellite]

The Chitwan National Park, Nepal's first national park established in 1973, was declared a World Heritage site by UNESCO in 1984. It contains the largest and least disturbed natural Sal hill forest and associated communities. Its fauna comprises Bengal tiger, Indian leopard, great one-horned rhinos, wild Asian elephant, gaur, golden monitor lizard, gharial and marsh crocodile.

Image:Sagarmatha districts.png

The Kamala Valley, also called Udayapur Valley is in Udayapur district in southeastern Nepal. It is about {{cvt|30|km}} long and between {{cvt|2|km}} and {{cvt|4|km}} wide. It is drained by the Triyuga river flowing east to join the great Koshi River. This valley lies between the Mahabharat Range to the north and the Sivalik Hills to the south, with an average elevation of about {{cvt|430|m}}.{{cite journal |author1=Darsie, R. F. Jr |name-list-style=amp |author2=Pradhan, S. P. |author3=Vaidya, R. G. |year=1992 |title=Notes on the mosquitoes of Nepal: II. New species records from 1991 collections |journal=Mosquito Systematics |volume=24 |pages=23–28 |url=http://www.mosquitocatalog.org/pdfs/MS24N01P023.Pdf |access-date=2008-10-13 |archive-date=2008-12-19 |archive-url=https://web.archive.org/web/20081219183024/http://www.mosquitocatalog.org/pdfs/MS24N01P023.Pdf |url-status=dead }}

The mouth of the valley opens onto a {{cvt|175|km}} rectangle of land where the Triyuga meets the Koshi river above the Koshi Barrage. It was designated the Koshi Tappu Wildlife Reserve in 1976, and is home to the last remaining population of wild Asian water buffalo in Nepal. The reserve is mostly wetlands, subject to seasonal flooding, but also includes some grasslands and small patches of riverine forest. It is a Ramsar Site.{{Cite book|author=Bhuju, U. R., Shakya, P. R., Basnet, T. B., Shrestha, S. |title=Nepal Biodiversity Resource Book. Protected Areas, Ramsar Sites, and World Heritage Sites |place=Kathmandu |publisher=International Centre for Integrated Mountain Development; Government of Nepal, Ministry of Environment, Science and Technology; United Nations Environment Programme, Regional Office for Asia and the Pacific |year=2007 |url=http://books.icimod.org/demo/uploads/ftp/Nepal%20Biodiversity%20Resource%20Book.pdf |url-status=dead |archive-url=https://web.archive.org/web/20110726170342/http://books.icimod.org/demo/uploads/ftp/Nepal%20Biodiversity%20Resource%20Book.pdf |archive-date=2011-07-26 }}

Imagery of Kamala valley:

[https://maps.google.com/maps/api/staticmap?center%3D26.8,86.85&zoom%3D10&size%3D640x640&maptype%3Dterrain&markers%3Dcolor:blue%7Clabel:K%7C26.7824,86.7947&sensor%3Dfalse terrain]

[https://maps.google.com/maps/api/staticmap?center%3D26.8,86.85&zoom%3D10&size%3D480x480&maptype%3Dsatellite&markers%3Dcolor:blue%7Clabel:K%7C26.7824,86.7947&sensor%3Dfalse satellite]

Traditionally, the Kamala Valley was primarily inhabited by the Dhanwar people (or Danuwar),Khatry, P. (1995). [http://www.thdl.org/texts/reprints/contributions/CNAS_22_01_04.pdf The Manjani System of the Danuwar State of the Kamala Valley: A Brief Study of an Egalitarian Judiciary]. Contributions to Nepalese Studies 22 (1): 43–55. but there is a fast-growing population of migrants from the Nepali hills and from India.

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{{DEFAULTSORT:Inner Terai Valleys of Nepal}}

Category:Valleys of Nepal

Category:Terai-Duar savanna and grasslands

Category:Grasslands of Nepal

Category:Plains of Nepal

Category:Wetlands of Nepal