Streams descending from the mountains deposit heavy materials such as rocks and boulders in a narrow, porous belt at the foot of the Shivaliks called the:

The Bhabar is a narrow belt, about 8 to 16 km wide, lying along the foot of the Shivalik hills, from the Indus to the Teesta. When rivers come down from the mountains onto the plains, they suddenly lose speed and deposit their heaviest load of pebbles, boulders and coarse gravel here.

Features of the Bhabar:

• It is made of coarse, porous material, so water seeps through it easily.
• Because of this porosity, small streams disappear underground in the Bhabar, flowing beneath the surface.
• The belt is not very suitable for agriculture, and is mostly covered by forest.
• It is continuous along the foothills and widest in the west.

The Terai:

• South of the Bhabar lies the Terai, a wet, swampy and marshy belt, about 15 to 30 km wide.
• Here, the underground streams of the Bhabar re-emerge on the surface, creating marshes.
• The Terai was once covered with thick forests, tall grasslands and abundant wildlife.
• Large parts of it have been cleared for agriculture, especially after independence, for resettling refugees.
• National parks such as Jim Corbett, Dudhwa and Valmiki lie in the Terai region.

Divisions of the Northern Plains (from north to south):

• Bhabar: coarse deposits at the foothills.
• Terai: marshy belt where streams re-emerge.
• Farther south lie the broad alluvial plains, with older and newer alluvium.

Duars:

In north Bengal and Assam, the foothill plains below the Bhutan hills are called the Duars (Dooars), known for tea gardens.

Why not the other options?

• ✗The Terai lies south of the Bhabar and is marshy, made of finer material.
• ✗A doab is the land between two rivers.
• ✗Duar is a regional name for the foothill plains of north Bengal and Assam.