WATER SCARCITY IN HIMALAYAS

WATER SCARCITY IN HIMALAYAS

Subject: Geography

Context:  A new study has said that Himalayan catchment areas may face water stress situations. They also note that if there is increased rainfall, this could lead to a water surplus situation.

Concept:

• The team studied five basins in the central Himalaya – Sutlej, ThuloBheri, Kali Gandaki, DudhKosi and Arun.
• The results show that the glacier-melt increases about 15% to 70% in a warmer environment with its present volume, but then decreases to 3%–38% substantially when the glacier volumes shrink.
• However, such a decrease can be compensated if there is increased rainfall and if a wetter scenario persists.

Himalayas

• The northward drift of the Indo-Australian plate resulted in its collision with the much larger Eurasian Plate.
• Due to which, the sedimentary rocks which were accumulated in the geosyncline known as the Tethys were folded to form the mountain system of western Asia and Himalaya.

Features:

• The Himalayas are geologically young and structurally folded mountains and represent the loftiest and one of the most rugged mountain barriers of the world.
• They form an arc, which covers a distance of about 2,400 km. Their width varies from 400 km in Kashmir to 150 km in Arunachal Pradesh.

Orientation:

• The general orientation of these ranges is from northwest to the southeast direction in the northwestern part of India.
• Himalayas in the Darjeeling and Sikkim regions lie in an east west direction.
• In Arunachal Pradesh they are from southwest to the northwest direction.
• In Nagaland, Manipur and Mizoram, they are in the north south direction.
• The Himalayan mountains consist of three parallel ranges in longitudinal extent:
• Great Himalaya or Himadri: It is the northernmost and the most continuous range consisting of the loftiest peaks with an average height of 6,000 m. World’s highest peaks are located in it.
• Lesser Himalaya or Himachal: To the south of Himadri, it is the most rugged mountain system and is known as Himachal or lesser Himalaya. The altitude varies between 3,700 and 4,500 m. It is well known for its hill stations like Kashmir, Kangra and Kullu Valleys.
• Shiwalik: It is the southernmost range with an altitude varying between 900 and 1100 m. These ranges are composed of unconsolidated sediments brought down by rivers from the main Himalayan ranges located farther north.
• There are large-scale regional variations within the Himalayas. On the basis of relief, alignment of ranges and other geomorphological features, the Himalayas can be divided into the following subdivisions:

Kashmir or Northwestern Himalayas.

Himachal and Uttaranchal Himalayas.

Darjeeling and Sikkim Himalayas.

Arunachal Himalayas.

Eastern Hills and Mountains.