The Northern Plains

Rivers from the Himalayas deposited huge alluvium. In exams link plains with river deposition.

Rivers repeatedly bring alluvium and make the soil fertile. Write alluvium as the cause of fertility.

This plain formed through long deposition by three major river systems. Remember the combined river systems for exams.

Bhabar is a belt of coarse pebbles at the foot of Shiwalik. In exams identify it as a porous belt.

In the Bhabar belt, streams disappear into porous deposits of coarse pebbles and boulders. In the Terai belt south of it, this water re-emerges near the surface, making the land very wet and marshy. Option B describes Bhabar, not Terai. Exam tip: remember Bhabar as the belt where water sinks, and Terai as the belt where it reappears.

Bhangar is the older alluvial deposit of the Northern Plains. It generally lies on higher terraces above the active floodplains and is not renewed by every annual flood. Because it is older, it may contain calcareous nodules called kankar. Khadar is different: it is newer alluvium found in lower floodplain areas and is more regularly renewed by river deposits.

The question gives two identifying clues: older alluvium and a higher part of the plains. Both point to Bhangar, so option B is correct. Khadar would be correct only for newer alluvium or active floodplain deposits. Terai is a wet marshy belt near the Himalayan foothills, while Bhabar is a porous belt where streams may disappear; neither term means higher older alluvium.

Khadar is new alluvium and receives fresh deposits during floods. In exams treat Khadar as more fertile.

The Ganga plain has been formed mainly by alluvium deposited by the Ganga and its tributaries. This material includes sand, silt and clay carried from the Himalayas and other regions, making it a vast river-built plain. Glacial deposits are associated mainly with glacier-dominated areas, not with the main formation of the Ganga plain. Exam tip: Sediments carried and deposited by rivers are called alluvium.

Khadar is the newer alluvial part of the Northern Plains. During repeated floods, rivers deposit fresh, fine and fertile silt in this area, so the Khadar floodplain is renewed regularly. The Shiwalik Hills are Himalayan foothills, not flood-deposited plains. Exam tip: associate fresh alluvium and flood renewal with Khadar.

The pebbly soil of Bhabar allows water to seep downward. Remember Bhabar's permeability for exams.

The Terai is a marshy, highly moist belt south of the Bhabar region. Streams that disappear into the porous Bhabar re-emerge here, producing surface water, waterlogging and marshes. These conditions support dense natural vegetation and provide suitable habitats for wildlife. Highly saline soil, by contrast, is generally unfavourable for forest growth. Exam tip: Link the Terai with re-emerging water, marshy land and dense forests.

Long deposition made the plain extensive and level. Link flatness with river deposition in exams.

Bhangar is the older alluvium of the Northern Plains and generally lies above the active floodplain. It contains kankar, which are hard deposits or nodules of calcium carbonate. Thus, kankar is an important indicator of Bhangar’s older alluvial nature. New alluvium is associated with Khadar, so option C is incorrect. Exam tip: Remember—Bhangar: old alluvium and kankar; Khadar: new and more fertile alluvium.

Rivers shift easily on low slopes and soft alluvium. Treat it as a feature of plain rivers in exams.

The Brahmaputra flows through a broad plain and carries a large quantity of sand, silt, and other sediments. Its channel often divides into several smaller channels and later joins again. Such a river pattern is called a braided channel. When the river’s speed decreases or its flow changes, the sediments are deposited between the channels. These deposited materials can gradually rise above the water and form temporary or permanent river islands.

Therefore, choice D is correct: braided flow and deposition. Desert winds, cooling lava, and sea-wave erosion do not explain the formation of islands in the Brahmaputra plain. The important sequence is that the river carries sediment, divides into several channels, deposits material, and leaves sedimentary bars or islands between the channels. This is why the Brahmaputra is especially known for river islands in its plain.

A delta forms from final deposits carried by rivers. Link deltas with river deposition in exams.

Alluvial soil and river water support agriculture. Mention both soil and water for agriculture in exams.

Low gradient in plains reduces river speed. Remember the relation between slope and velocity in exams.

On low gradients a river erodes sideways and bends. Link meanders with plain rivers in exams.

A doab is the fertile tract of land lying between two rivers. The Punjab Plain has many such tracts between rivers of the Indus system and their tributaries, so doabs are prominent there. Waves of the Bay of Bengal are associated with coastal areas, not the Punjab Plain. Exam tip: Remember doab as land between ‘two waters’ or two rivers.