Surkhet Valley

The Inner Terai Valleys of Nepal (Nepali: भित्री मधेश) comprise several elongated river valleys in the southern lowland Terai part of the country. These tropical valleys are enclosed by the Himalayan foothills, viz the Mahabharat Range and the Sivalik Hills farther south. The Inner Terai is called "bhitri Terai " in Nepali language.

The Inner Terai Valleys are part of the Terai-Duar savanna and grasslands ecoregion. They are filled up with coarse to fine alluvial sediments. The Chitwan Valley and the Dang and Deukhuri Valleys are some of the largest Inner Terai Valleys.

Malaria was prevalent in this region until the late 1950s. Since its eradication, the area became a viable destination for large-scale migration of people from the hills, who transformed the area from virgin forest and grassland to farmland.

The Himalayas were formed by the collision of the Indian sub-continent with Eurasia, which began about 50 million years ago and continues today. The oceanic crust in front of India slid under Eurasia, pushing up the Tibetan plateau. The Indian continental crust is also pushing under Tibet, but is partly compressed and thrust upward to form the Himalayan mountain range, extending for over 2400 km and rising as high as 8848 m at Mt. Everest Chomolungma.

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