The Himalayan Rivers

Bhangar is older alluvium and Khadar is newer alluvium. Exam tip: connect them with flood plain deposits.

Khadar is the newer alluvium found in river floodplains. During floods, rivers deposit fresh layers of silt, sand and other sediments, so Khadar is renewed repeatedly. In contrast, Bhangar is older alluvium, usually lying above the flood level and therefore not receiving fresh deposits regularly. Exam tip: remember Khadar as new floodplain alluvium and Bhangar as old alluvium.

Erosion may dominate upstream and deposition downstream. Exam tip: connect slope with river work.

In the Ganga plain, the gentle gradient makes the river flow relatively slowly. It erodes laterally along the outer bank of a bend and deposits sediment along the inner bank. Together, these processes produce meanders. Steep gradients and vertical erosion are more typical of a river’s upper, mountainous course. Exam tip: associate meanders in plains with lateral erosion and deposition.

A large basin can add more water and tributaries. Exam tip: connect basin size with floods.

A tributary network is the pattern formed by the smaller streams and rivers that join a main river. In the Himalayan region, many tributaries originate in mountains, valleys, glaciers, or areas receiving heavy rainfall. When they join the main river, they add water and usually bring eroded sediment as well. The main river therefore develops a larger discharge and carries material that may later be deposited in plains, floodplains, or deltas. A dense network also enlarges the drainage basin served by the river.

Option A is correct because it identifies the main direct result: greater supply of water and sediment to the main channel. A tributary does not make the main river flow backward from the sea, remove all its water, or turn it into a volcano. The idea of a drainage basin is also useful: it is the area drained by the main river and its tributaries. Thus, a dense tributary network usually means a well-connected and substantial river system.

Northern rivers may link with Himalayas and southern rivers with Peninsular highlands. Exam tip: check source and direction.

Hooghly belongs to the lower Ganga drainage system and is associated with the Ganga delta. In a delta, the river divides into distributary channels as it approaches the sea. Hooghly is one of the important channels connected with this deltaic network. A distributary branches away from the main river, so it should not be confused with a tributary, which joins the main river and adds water to it.

Option B is correct because it places Hooghly in the distributary system of the Ganga delta. It is not the main stream of the Indus, the source of the Yamuna, or a mountain branch of the Kosi. Those options connect it with unrelated rivers or incorrect river roles. The same river relationship appears in the earlier drainage question: Hooghly is understood through its deltaic connection with the Ganga. Therefore, option B is the only suitable choice.

High sediment can deposit in a delta and form branches. Exam tip: connect sediment with delta development.

Ganga and Brahmaputra deposit towards the Bay of Bengal. Exam tip: connect the delta with the bay.

When slope decreases the river can spread sediments. Exam tip: connect foothills with alluvial fans.

A river’s ability to erode and carry sediment depends greatly on its energy, which is related to slope, discharge and velocity. In the Himalayan mountains, the channel often has a steep gradient, so water flows rapidly and cuts into banks and beds. When the river reaches the plains, the land becomes much flatter. The fall in slope reduces the river’s velocity and transporting power, especially when the channel becomes wider and the flow spreads.

Option C is correct because reduced slope and velocity make the river less able to carry its sediment load. When the river loses energy, sand, silt and other particles settle on the bed or flood plain, producing deposition. The source does not need to change, glaciers do not need to expand, and increasing sea tides are not the main general reason for this inland transition. The key sequence is steep slope and erosion in the mountains, followed by gentler slope, slower flow and deposition in the plains.

Alluvial soil and river water are useful for agriculture. Exam tip: connect river plains with farming and settlement.

The Indus system is linked with the geography of both India and Pakistan. Exam tip: remember regional location.

River behaviour changes as relief changes along its course. Exam tip: connect route with relief.

Khadar and Bhangar are both types of alluvial deposits found in the northern plains, but they differ in age and position. Khadar is newer alluvium deposited by relatively recent floods, so it is often replenished with fresh silt and may be more fertile. Bhangar is older alluvium, usually found on higher terraces and less frequently renewed by floods. Therefore, option A correctly explains why their agricultural value can differ.

The key comparison is new alluvium versus old alluvium. Floodwaters periodically spread fine sediments over the low-lying flood plain, producing Khadar. These fresh deposits can restore nutrients and improve cultivation, although floods may also damage crops. Bhangar has existed longer and may contain older, less frequently renewed material, sometimes with concentrations such as kankar. The other options misidentify both landforms. Thus A is correct and the supplied explanation is accurate.

A stream joining the main river is called a tributary. Exam tip: observe joining and branching directions.

A stream branching away in delta is called a distributary. Exam tip: connect distributary with delta.

Himalayan river plains are favourable for farming and settlement. Exam tip: connect river plains with human geography.

More water and sediment during monsoon affect floods. Exam tip: connect season with river risk.