Bhabar and Terai Region of Uttarakhand :

Uttarakhand lies on the southern slope of the Himalaya range, and the climate and vegetation vary greatly with elevation, from glaciers at the highest elevations to subtropical forests at the lower elevations. The highest elevations are covered by ice and bare rock. Below them, between 3,000 and 5,000 metres (9,800 and 16,400 ft) are the western Himalayan alpine shrub and meadows. The temperate western Himalayan subalpine conifer forests grow just below the tree line. At 3,000 to 2,600 metres (9,800 to 8,500 ft) elevation they transition to the temperate western Himalayan broad leaf forests, which lie in a belt from 2,600 to 1,500 metres (8,500 to 4,900 ft) elevation. Below 1,500 metres (4,900 ft) elevation lie the Himalayan subtropical pine forests. The Upper Gangetic Plains moist deciduous forests and the drier Terai-Duar savanna and grasslands cover the lowlands along the Uttar Pradesh border in a belt locally known as Bhabar. These lowland forests have mostly been cleared for agriculture, but a few pockets remain. Uttarakhand borders Tibet Autonomous Region of China to the north; the Sudurpashchim Pradesh of Nepal to the east; the Indian states of Uttar Pradesh to the south and Himachal Pradesh to the west and north-west.Uttarakhand is known for the natural environment of the Himalayas, the Bhabhar and the Terai.

Bhabar Region :

Bhabar is a region south of the Lower Himalayas and the Shiwalik Hills.It is the alluvial apron of sediments washed down from the Siwaliks along the northern edge of the Indo-Gangetic Plain.

The name Bhabhar refers to a local tall-growing grass, Eulaliopsis binata, used for the manufacture of paper and rope.

Overview :

Bhabhar is the gently-sloping coarse alluvial zone below the Siwalik Hills (outermost foothills of Himalaya) where streams disappear into permeable sediments. The underground water level is deep in this region, then rises to the surface in the Terai below where coarse alluvium gives way to less permeable silt and clay. The Ganges River lies to the west and Sharda to the east.

Being at the junction of Himalayas and the Indo-Gangetic Plain, Bhabhar contains almost all the important trade and commerce hubs of Uttarakhand state. Due to the top-soil replenishment every monsoon,it is also a fertile area with large yields per unit area.

History :

In 1901 Bhabhar was also one of four division of Nainital district. It included 4 towns and 511 villages with a combined population of 93,445 (1901), spread over 1,279 square miles (3,310 km2). It corresponded to the current subdivision of Haldwani.

Terai Region :

The Terai or Tarai is a lowland region in southern Nepal and northern India that lies south of the outer foothills of the Himalayas, the Siwalik Hills, and north of the Indo-Gangetic Plain. This lowland belt is characterised by tall grasslands, scrub savannah, sal forests and clay rich swamps. In northern India, the Terai spreads from the Yamuna River eastward across Himachal Pradesh, Haryana, Uttarakhand, Uttar Pradesh and Bihar.

The region is called 'tarai' meaning "the low-lying land, plain" and especially "the low-lying land at the foot of the Himalayas" . The  meaning "lands lying at the foot of a watershed" or "on the banks of a river; low ground flooded with water, valley, basin, marshy ground, marsh, swamp; meadow".

Geology :

The Terai is crossed by the large perennial Himalayan rivers Yamuna, Ganges, Sarda, Karnali, Narayani and Kosi that have each built alluvial fans covering thousands of square kilometres below their exits from the hills. Medium rivers such as the Rapti rise in the Mahabharat Range. The geological structure of the region consists of old and new alluvium, both of which constitute alluvial deposits of mainly sand, clay, silt, gravels and coarse fragments. The new alluvium is renewed every year by fresh deposits brought down by active streams, which engage themselves in fluvial action. Old alluvium is found rather away from river courses, especially on uplands of the plain where silting is a rare phenomenon.

A large number of small and usually seasonal rivers flow through the Terai, most of which originate in the Siwalik Hills. The soil in the Terai is alluvial and fine to medium textured. Forest cover in the Terai and hill areas has decreased at an annual rate of 1.3% between 1978 and 1979, and 2.3% between 1990 and 1991. With deforestation and cultivation increasing, a permeable mixture of gravel, boulders and sand evolves, which leads to a sinking water table. But where layers consist of clay and fine sediments, the groundwater rises to the surface and heavy sediment is washed out, thus enabling frequent and massive floods during monsoon, such as the 2008 Bihar flood.

The reduction in slope as rivers exit the hills and then transition from the sloping Bhabhar to the nearly level Terai causes current to slow and the heavy sediment load to fall out of suspension. This deposition process creates multiple channels with shallow beds, enabling massive floods as monsoon-swollen rivers overflow their low banks and shift channels. Many areas show erosion such as gullies.

In Uttarakhand Terai region extends in : Haridwar district, Udham Singh Nagar and Nainital districts.

Inner Terai :

The Inner Terai consists of five elongated valleys located between the Mahabharat and Shivalik ranges. From north-west to south-east these valleys are:

• Surkhet Valley in the Surkhet district, north of the Kailali and Bardiya districts;
• Dang Valley ) in the Dang Deokhuri district;
• Deukhuri Valley located south of the Dang Valley;
• Chitwan Valley stretching across the Chitwan and Makwanpur districts;
• Kamala Valley, also called Udayapur Valley in the Udayapur district north of the Siraha and Saptari districts.

Most of these valleys are 5–10 km (3.1–6.2 mi) wide (north-south) and up to 100 km (62 mi) long (east-west).

Outer Terai :

The Outer Terai begins south of the Siwalik Hills and extends to the Indo-Gangetic plain. In the Far-Western Region, Nepal it comprises the Kanchanpur and Kailali districts, and in the Mid-Western Region, Nepal Bardiya and Banke districts. Farther east, the Outer Terai comprises the Kapilvastu, Rupandehi, Nawalparasi, Parsa, Bara, Rautahat, Sarlahi, Mahottari, Dhanusa, Siraha, Saptari, Sunsari, Morang and Jhapa districts.\

East of Banke the Nepalese Outer Terai is interrupted where the international border swings north and follows the edge of the Siwaliks adjacent to Deukhuri Valley. Here the Outer Terai is entirely in Uttar Pradesh's Shravasti and Balrampur districts. East of Deukhuri the international border extends south again and Nepal has three more Outer Terai districts.