CDS (II) 2021 General Knowledge · Question 98 of 120

Correct — C, Bhabar. The stem is lifted almost word for word from the standard school description of the northern plains. Where the Himalayan streams leave the mountains and hit the sudden break of slope at the foot of the Shiwaliks, their velocity collapses, and the first material they can no longer carry is the heaviest — rocks, boulders and coarse pebbles. That deposition builds a narrow porous belt of about eight to ten kilometres running parallel to the Shiwalik foothills, and it is called the bhabar. The belt is so coarse and so permeable that the smaller streams sink into it and vanish underground, to re-emerge a little further south. That is the whole mechanism: a break of slope, a drop in carrying capacity, and the coarsest load dumped first.

• (a)Khadar — Khadar is the newer alluvium of the active floodplains, renewed by fresh silt at every flood. It is fine-textured and fertile, the opposite of a bed of boulders.
• (b)Bhangar — Bhangar is the older alluvium lying above the present flood level, often carrying nodules of calcareous kankar. Again fine alluvium, and further south than the foothill zone.
• (d)Terai — The tarai lies immediately south of the bhabar, roughly ten to twenty kilometres wide, and it is where the streams that disappeared into the bhabar re-emerge without properly marked channels, creating marshy, swampy ground with a luxuriant growth of vegetation. It receives the water, not the boulders.

The northern plains are alluvium laid down by the Himalayan rivers over a foredeep, with the deposits reaching depths of the order of one to two thousand metres. From north to south they fall into three zones — the bhabar at the foot of the hills, the tarai below it, and the alluvial plains beyond, which are themselves divided into the older bhangar and the newer khadar.

The four names are asked about constantly, and the reliable way to keep them apart is to walk them in order from the mountains southward rather than to memorise them as a list. Coarse boulders drop first at the break of slope, giving the bhabar; the water that sank into that porous belt comes back to the surface just south of it, giving the marshy tarai; further out the river spreads fine silt, and the difference between the older sheets left above flood level and the fresh silt of the active floodplain is the difference between bhangar and khadar. Land use follows the same order — the bhabar is too coarse and too dry at the surface for good cropping, the tarai has been drained and settled over the past century, and the khadar is the most fertile of the four.

• The bhabar is a narrow belt of about eight to ten kilometres running parallel to the Shiwalik foothills at the break of slope.
• Streams and rivers coming out of the mountains deposit heavy rocks and boulders there and at times disappear into the porous bed.
• The tarai lies south of the bhabar, roughly ten to twenty kilometres wide, where those streams re-emerge without well-marked channels and create marshy conditions with luxuriant vegetation.
• Bhangar is the older alluvium above the present flood level, frequently containing calcareous kankar nodules; khadar is the newer alluvium of the active floodplain, renewed at each flood.
• The alluvium of the northern plains reaches a maximum depth of the order of one to two thousand metres.

• Swapping bhabar and tarai — the boulders are in the bhabar, the marsh is in the tarai.
• Assuming khadar is the older deposit because the word sounds archaic; khadar is the newer alluvium.
• Treating the bhabar as fertile. Its coarse, porous bed and the loss of surface water make it poor cropping land.

As a one-line identification of the belt from its description, or as a north-to-south sequencing item across the four zones.

• practice — not a real PYQ

  The marshy, swampy belt lying immediately south of the bhabar, where streams re-emerge without well-marked channels, is known as the

  • (a)khadar
  • (b)tarai
  • (c)bhangar
  • (d)dun

  Answer(b) tarai — roughly ten to twenty kilometres wide, it is where the water that sank into the porous bhabar comes back to the surface.

• practice — not a real PYQ

  Calcareous kankar nodules are characteristically found in which one of the following?

  • (a)Khadar
  • (b)Bhabar
  • (c)Bhangar
  • (d)Tarai

  Answer(c) Bhangar — the older alluvium standing above the present flood level, unlike the khadar, which fresh silt renews at every flood.