The Himalayas – A presentation by ACWADAM

This presentation by ACWADAM deals with the Himalayan mountain system,  the planet's highest, and home to the world's highest peaks. It specifically deals with the various divisions, the kind of structures present and the presence of groundwater in the massive mountain system. It is the youngest mountain chain in the world and has got few of the highest peaks in the world such as Mt. Everest (8852 m above msl). Himalayas is still rising and consists of the following co-extensive sub-ranges -

• Siwalik Foothills: These are below 900m in elevation and are comprised of sedimentary rocks that are unconsolidated in nature deposited in a lake formed after collision of plates. These ranges are fossiliferous and are relatively water endowed due to their partially consolidated nature of sediments. Springs are common and wells are observed in a few areas.
• Lesser Himalaya: These unfossiliferous ranges have elevation in the range of 900 – 3000 m and are comprised of slightly metamorphosed sedimentary rocks such as quartzites, slates, phyllites and limestones. Springs are the main source of water. Reducing discharges is a major concern in these ranges.
• Greater Himalaya: These are high snow-capped peaks above 3000m and are comprised of sedimentary, metamorphic and igneous rocks. Sediments and high grade metamorphic rocks are intruded by granites of different ages. These are the water-scarce regions and are dependant on springs.
• Trans/Tethys Himalaya: These ranges lie beyond the Greater Himalayas and have altitudes between 3000 - 5000m. They are the origin of major rivers and are comprised of sedimentary, metamorphic and igneous rocks. The areas are traditionally dependant on springs.

This presentation is part of the training modules on planning, development and management of groundwater with special reference to watershed management programmes by ACWADAM. Please write to ACWADAM at acwadam@vsnl.net for sourcing these presentations.