The Great Northern Plains
The Great plain of Northern India lies on the south of the Himalayas. It is, in fact, bounded by the Himalayas on the north and the Deccan plateau on the south. This plain stretches for about 2,400 km from east to west and 200 to 400 km from north to south. It covers an area of about 5,80,000 sq km.
The Great plain of Northern India was formed by the sediments brought down by the Indus-Ganga-Brahmaputra and their tributaries and it is popularly known as the Indo-Ganga-Brahmaputra plain. Geologists suggest that there was a shallow trough or geosyncline in between the Himalayas and the Deccan plateau during the latter geological period of the formation of the Himalayas.
After the upliftment of the Himalayas, sediments and debris brought down by the rivers, began to accumulate there to form the vast alluvial plain of northern India.
This extensive plain is level and monotonous; it is characterized by some local diversities. Hence, it may be classified into three divisions:
- The Punjab plain drained by the Indus,
- The Ganga plain drained by the Ganga and
- The Brahmaputra valley drained by the Brahmaputra.
1. The Punjab Plain
The Western part of the Northern plain is known as the Punjab plain. The plain is drained by the Indus and its tributaries, such as, the Sutlej, Beas and Ravi. Only a part of the Indus basin lies in India. The plain slopes gently down towards the south-west; hence the rivers follow the slope of the land. The plain is mostly made of silts. The soil is porous. The plain that is formed by the deposition of new alluvium near the river banks is called Bet.
Large boulder, gravel, sand and clay cover the foot-hill regions of the Punjab plain and they are known as ‘Bhabar’ plain or bhabar soil. This soil cannot hold water. The new alluvium deposited near the river banks of these rivers forms a plain called Bet.
2. The Ganga Plain
The major portion of the Great Indian Plain consists of tile Ganga basin. It extends from the eastern margin of the Punjab in the west to Bangladesh border in the east. This is an extensive plain encompassing states such as Uttar Pradesh, Bihar and West Bengal.
It is drained by the rivers such as Yamuna, Ganga, Ghaghara, Gandak, Kosi and Tista from the Himalayas in the north and Chambal, Betwa, Son and Damodar from the plateau in the south. The entire region slopes towards south and south-east.
It is monotonous alluvial plain with little undulation. The lower reaches of the Ganga plain is slightly above the sea-level; however, the upper portion rises up to 200 meters. The Ganga forms a great delta on its mouth. Its deltaic part presents the three distinctive features of delta formation, such as, the moribund delta, mature delta and active delta.
The Ganga plain is the most populous part of India. People of this plain are mainly engaged in agriculture. Trade, industry and commerce are also prosperous.
Divisions: This plain may be divided into three regions:
- Upper Ganga plain: It stretches from the Yamuna river in the west to Allahabad city in the east,
- Middle Ganga plain: It stretches from Allahabad (Uttar Pradesh) in the west to Rajmahal hill in the east, and
- Lower Ganga plain: It stretches from Rajmahal hill to the Bay of Bengal.
3. The Brahmaputra Valley
It lies in the north-eastern part of the country and is hemmed between the Arunachal Himalayas on the north and the Meghalaya Plateau on the south.
The valley presents a flat plain. It is formed by the debris brought down by river Brahmaputra and its innumerable tributaries. The plain seldom rises above 100 meters above the sea-level and slopes gently towards the west. Ranges of hills are found standing on both sides of the river.
Innumerable Sandbars and islets are found on the Brahmaputra and the river flows out in different channels avoiding obstacles of sandbar. Majuli Island is by far the largest sandbar ever formed on any other river bed in the world. The green Brahmaputra valley is noted for tea plantation.