The Himalayan Rivers

Himalayan rivers get water from rainfall and melting snow. Exam tip: remember them as perennial rivers.

Himalayan rivers receive water from more than one source. Snow and glaciers stored high in the mountains melt seasonally and feed streams and rivers, especially during warmer months. Rainfall, including monsoon rain, is another important source and can increase river discharge greatly. Because glaciers and snow continue to provide meltwater while rainfall varies, many Himalayan rivers are perennial, meaning they carry water through much of the year.

Option B is correct because glaciers and melting snow are a major source of Himalayan river water. Option A is wrong because desert rainfall is not the defining source, and the word “only” also excludes other sources. Sea waves do not supply these inland rivers, and underground oil is not water. The most complete school-level statement would mention both snow or glaciers and rainfall; among the given choices, “glaciers and melting snow” is the only suitable answer.

Direct answer: C, the Indus river system. The major Himalayan river systems commonly studied in India are the Indus, the Ganga, and the Brahmaputra. They receive water from snow, glaciers, and rainfall and generally have water for much of the year. Option C is correct because the Indus rises in the high Tibetan region and flows through the Himalayan and northwestern drainage areas. Option A, Narmada, is a major Peninsular river flowing through a rift valley. Option B, Tapi, is also a Peninsular river. Option D, Sabarmati, is a west-flowing Peninsular river system, not one of the major Himalayan systems. Memory cue: the three major Himalayan systems are Indus, Ganga, Brahmaputra.

Direct answer: D, the Himalayan river system. The Ganga begins in the Himalayan region through the Bhagirathi source at Gangotri, joins the Alaknanda at Devprayag, and then flows across the northern plains. It has many tributaries, receives water from snow, glaciers, and monsoon rainfall, and is therefore classified as a Himalayan river system. Option D is correct. Option A is wrong because the Ganga is not a purely Peninsular system. Option B is wrong because it is not a desert river system; it flows through a large fertile plain. Option C is wrong because the Ganga is a large continental river system, not a small coastal river. Memory cue: Ganga comes from the Himalayas, so classify it as Himalayan.

Direct answer: A, Himalayan rivers. A river system means a main river and its tributaries. The Brahmaputra rises in the Tibetan Himalaya, enters India through the north-east, flows through Assam, and joins the Ganga system in Bangladesh. Therefore it belongs to the Himalayan group. Option A is correct because its source, long course, snowmelt and monsoon-fed flow fit this group. B is wrong because peninsular rivers flow mainly over the old plateau. C is wrong because short western coastal rivers are small, short streams. D is wrong because inland drainage ends in lakes or desert basins instead of reaching the sea. Memory cue: Brahmaputra means north-east and Himalaya.

In the upper course steep slopes help rivers cut deep valleys. Exam tip: connect upper course with erosion.

A steep slope gives the river fast flow and more cutting power. Exam tip: remember the link between slope and erosion.

When slope decreases in the plains rivers deposit alluvium. Exam tip: understand the cause of alluvial plains.

The Ganga and its tributaries formed a vast alluvial plain. Exam tip: connect river deposition with plain formation.

In plains low slope makes rivers form meanders. Exam tip: remember low gradient and bends together.

Direct answer: Option C is correct. Himalayan rivers carry abundant water because they receive rainfall and, in many cases, meltwater from snow and glaciers. When these rivers enter the plains, the land slope becomes gentle. A gentler slope reduces velocity, so the river cannot move all its water and sediment efficiently. If heavy rain or rapid snowmelt adds more water, the channel may overflow its banks and cause floods. Option C gives the two important linked conditions: low slope and large water volume. Option A is not the main general cause; sea waves do not normally create floods far across the river plains. Option B is wrong because a completely dry river cannot produce this kind of flooding. Option D is wrong because Himalayan rivers are connected with glaciers and snow, not their total absence. Remember the chain: much water plus gentle slope plus limited channel capacity can produce flooding.

Perennial water and alluvial plains support farming. Exam tip: study irrigation and fertile soil together.

The Indus system is linked with high Himalayan regions. Exam tip: remember its mountainous source region.

After leaving the mountains it flows in the plains as the Ganga. Exam tip: note sections where names are used.

The Yamuna is one of the major tributaries of the Ganga river system. It rises from the Yamunotri Glacier and joins the Ganga at Prayagraj. The Narmada and Krishna are Peninsular river systems, so they are not associated with the Yamuna. Exam tip: remember the Yamuna–Prayagraj–Ganga confluence link.

They are counted among major tributaries of the Ganga. Exam tip: remember tributaries coming from the north.

Direct answer: A, floods and shifting course. Kosi carries much sediment from the Himalaya. When it reaches flatter land, its speed falls and sediment is deposited. The river may then change its channel, while heavy monsoon rain causes floods. A is correct because both flooding and channel shifting are well-known Kosi problems. B is wrong: Kosi is not permanently dry. C is wrong: lava belongs to volcanic activity, not ordinary river flow. D is wrong: tides are caused mainly by the gravitational pull of the Moon and Sun, not by Kosi. Exam cue: Kosi is often remembered as a flood-prone, changing river.

Direct answer: Option B is correct. In India, the Brahmaputra is chiefly associated with Assam and the north-eastern region. The river enters India in Arunachal Pradesh as the Siang or Dihang, then flows through Assam, where it becomes a very wide, braided river and receives important tributaries. Step by step: it rises in the Tibetan region; enters north-eastern India; crosses Arunachal Pradesh; flows mainly across Assam; then enters Bangladesh and joins the Ganga system. Option A is wrong because Rajasthan is a dry western desert region, not the main Indian course of the Brahmaputra. Option B is correct because Assam is its principal Indian valley. Option C is wrong because the Malabar Coast is in south-western India and is associated with short west-flowing rivers. Option D is wrong because the Rann of Kachchh is a salt marsh in Gujarat. Exam cue: Brahmaputra in India strongly points to Assam and the north-east.

Heavy rainfall in the north east and Himalayan sources increase its water. Exam tip: mention both rainfall and sources.

Himalayan rivers rise in mountains and flow far across plains. Exam tip: remember their long courses.

Himalayan rivers erode rocks in their upper courses, transport the eroded sediments, and deposit them mainly in the plains. Therefore, the option including all three processes is correct. “Erosion only” is more closely associated with the upper course, not with the complete work of a river. Exam tip: remember the three main river actions in order—erosion, transportation, and deposition.

Himalayan rivers carry large amounts of silt, sand and other sediments. At their mouth, where the river enters a sea or lake, the flow slows down and the sediments are deposited, forming a delta. A steep mountain slope helps erosion and transport of sediments, but it is not the direct cause of delta formation. Exam tip: link a delta with deposition at a river mouth.

The Ganga Brahmaputra forms one of the large delta regions. Exam tip: remember delta formation.

A tributary is a smaller stream that joins a larger main river. As it joins, it contributes its own flowing water and may also bring transported sediment such as sand, silt, and clay. This can increase the discharge and sediment load of the main river, although the amount depends on rainfall, landforms, rock type, and erosion in the tributary basin. Tributaries therefore help build the drainage network rather than ending the main river.

The correct choice is D: tributaries add water and sediment to the main river. They do not normally terminate the main channel, and they do not always travel separately to the sea. A river cannot be turned into mountains by a tributary. The key idea is the meaning of “tributary”: it is a contributing branch that flows into a larger stream and strengthens the main drainage system.

An alluvial fan forms where a river leaves a steep mountain valley and enters a much flatter plain. Because the slope suddenly becomes gentler, the river loses speed and cannot carry all its sand, silt, and gravel. It deposits these materials in a spreading, fan-shaped body. Therefore, option A is correct. Tides, snowfall in deserts, and lava deposition in lakes do not explain the formation of an alluvial fan by a Himalayan river.

The essential sequence is mountain to plain, reduced slope, reduced velocity, and deposition. Himalayan rivers carry large quantities of eroded material from the mountains. At the foothills, the change in gradient causes some of this load to settle and spread outward. Repeated deposition gradually produces the fan shape. Thus the description in option A gives both the correct location and process. The supplied answer and explanation are accurate.