The Shivalik hill ranges is a part of sub Himalayan mountain system extending from the state of Jammu and Kashmir on the west to Uttarnachal in the east, covering Himachal Pradesh, and parts of Punjab and Haryana. A large part of Shivaliks lies in Himachal Pradesh, the upper catchment of Shivalik region of Haryana.
The Shivalik region in Haryana is spread over 3,514 square kilometres of districts Ambala, Panchkula and parts of Yamunanagar. Shivalik Development Board has administratively defined the extent of the region to cover 430 Gram Panchayats from Ambala, 162 GPs from Panchkula and 282 GPs from Yamunanagar. In district Panchkula, 45% of total area falls under hilly tracts, whereas Yamunanagar has 9% of hilly area and Ambala only 0.2%.
Shivaliks is perhaps the most fragile ecosystem in the country. In less than half a century, burgeoning population of human and livestock have stressed the natural resources of Shivaliks, thereby threatening the survival of flora and fauna of Shivaliks. In addition, frequent forest fires and improper land use management, have resulted in steady but obvious natural resource degradation, especially that of land and water resources and decimation of floral and faunal wealth. The area once dotted with perennial springs and gentle streams got converted in to ever-widening and deepening choes (torrents). The land affected by the choes has increased manifold during the last half century.
The Shivaliks at places present a highly dissected plateau topography created by ephemeral streams. Weathering and denudation have produced a variety of erosional landform features such as rills, gullies, scarps and variously shaped ridges and amphitheatrical basins. The drainage channels carry huge amount of detritus and bed load creating problems of silting of reservoirs, deposition of sand on agricultural fields and disrupting communication.
The districts described above show distinct variation in topography, lithology and water availability. Based on the topography and geomorphology they can be divided into four major groups as under.
1. Highly dissected region (with gradient more than 15%) found in Pinjore and Morni blocks of District Panchkula
2. Moderately dissected region (with gradient between 10 to 15%) found in s ome parts of Sadaura and Bilaspur blocks of Yamuna Nagar, also Morni and Pinjore Block of Panchkula.
3. Un-dissected region (with gradient between 5 to 10%) found in s ome parts of Bilaspur block of Yamunanagar and Naraingarh block of Ambala
4. Plains (with gradient less than 5 %) found in the rest of the area
The Shivalik hills in this area mainly comprise of alluvium and boulder conglomerate with clay bands. The hilly regions comprise of conglomerates, medium to coarse grained, pale brown sandstones. Thin light brown/ chocolate coloured sandy clays were also observed in the lower parts. At places, highly weathered closely jointed rock exposure in the form of silt stones clays, were also observed. The foothill zones comprises of boulders, pebbles, gravels, sand and clays. It is followed by alluvial deposits of sand, sand with clay.