The Northern Plains

The Northern Plains of India are a vast and fertile region formed by the alluvial deposits of the Indus, Ganga, and Brahmaputra rivers. Stretching approximately 3,200 km from east to west and varying in width between 150-300 km, these plains are a crucial agricultural and ecological zone.

Formation and Characteristics

Alluvial Deposits:

• • Source: Deposited by the Indus, Ganga, and Brahmaputra rivers.
  • Depth: The maximum depth of these deposits ranges from 1,000 to 2,000 meters.

General Elevation:

• • Elevation: Generally 50-150 meters above mean sea level.
  • Features: Characterized by a relatively flat terrain with some variations due to fluvial processes.

Major Zones of the Northern Plains

Bhabar:

• • Location: A narrow belt, approximately 8-10 km wide, located parallel to the Shivalik foothills.
  • Features: The region where rivers and streams deposit heavy materials such as rocks and boulders, resulting in a porous and gravelly area. Streams often disappear or become less visible due to rapid infiltration.

Tarai:

• • Location: Lies south of the Bhabar zone, with a width of about 10-20 km.
  • Features: Known for its marshy and swampy conditions created by streams and rivers re-emerging without well-defined channels. It supports lush vegetation and a diverse range of wildlife, making it an ecologically rich area.

Alluvial Plains:

• • Sub-divisions:
    • Khadar: Represents the newer alluvial deposits found in the floodplains. These are areas of active sedimentation and often have fertile soil.
    • Bhangar: Comprises older alluvial deposits, characterized by more mature and stable landforms. The soil is typically less fertile compared to Khadar due to its age and sedimentary history.

Physiographic Features

Fluvial Landforms:

• • Sand Bars: Formed by the deposition of sediment in river channels.
  • Meanders: Curved river paths formed due to sediment deposition and erosion processes.
  • Ox-Bow Lakes: Crescent-shaped lakes formed when a meander becomes isolated from the main river channel.
  • Braided Channels: Formed by multiple channels splitting and rejoining due to high sediment loads and variable flow conditions.

Brahmaputra Plains:

Noted for its riverine islands and sandbars. The region frequently experiences flooding and shifting river courses, contributing to the formation of braided streams.

River Deltas

Sunderbans Delta:

• • Location: Formed by the confluence of the Ganges, Brahmaputra, and their tributaries.
  • Features: One of the largest and most famous deltas in the world. It is characterized by a complex network of rivers, tidal waterways, mudflats, and mangroves.

Water Divides and River Flow

Haryana and Delhi:

• These states form a water divide between the Indus and Ganga river systems, influencing the direction and distribution of river waters in northern India.

Brahmaputra River:

• Originates in Tibet, flows southeast through India, and takes a sharp 90° turn southward at Dhubri before entering Bangladesh.

Agricultural Significance

• Soil: The alluvial soil in these plains is highly fertile, supporting a variety of crops.
• Crops: Includes wheat, rice, sugarcane, and jute. The fertile soil supports a large and dense population due to its high agricultural productivity.