Drainage Systems in India

Correct answer: A. Deep valleys cut across the rising Himalayas

Antecedent rivers keep their older course even after uplift. Exam tip: connect gorges with antecedent flow.

Correct answer: A. Because they mainly depend on monsoon rainfall

Peninsular rivers are rain-fed, so their flow varies seasonally. Exam tip: connect seasonal flow with rainfall dependence.

Correct answer: A. It increases sediment load due to intense erosion

The Himalayas are young fold mountains with steep slopes, relatively unstable rocks and active erosion. Rainfall, snowmelt and landslides break and carry rock material into rivers, so these rivers carry a high sediment load. Option B is incorrect because intense erosion makes rivers sediment-rich, not sediment-free. Exam tip: associate young, high mountains with stronger erosion and greater sediment load.

Correct answer: A. Rocks of uniform resistance allow a branching network

Dendritic pattern forms on general slope and uniform rock resistance. Exam tip: remember the tree-like shape.

Correct answer: A. Because streams follow bands of hard and soft rocks

Trellis pattern is controlled by rock structure. Exam tip: identify parallel valleys and angled junctions.

Correct answer: A. Streams spread outward from it

Radial pattern shows outward flow from a high centre. Exam tip: remember areas such as Amarkantak.

Correct answer: A. They indicate rock joints and fractures

In rectangular pattern streams follow fractures. Exam tip: treat right-angled bends as a key clue.

Correct answer: A. Due to steep and uniform slope

The direct answer is A: streams flow nearly in one direction in a parallel pattern because the land has a steep and fairly uniform slope. A drainage pattern is controlled by the shape and structure of the surface. On a strong, similar gradient, streams tend to follow the same downhill direction, producing roughly parallel channels and tributaries. Option A is correct because it identifies slope as the controlling factor. Option B is wrong because low rainfall and a closed basin may affect the amount of water or the drainage arrangement, but they do not define a parallel pattern. Option C is wrong because right-angled fractures commonly produce a rectangular drainage pattern, not a parallel one. Option D is wrong because heavy delta deposition concerns the river mouth and does not explain parallel streams across a sloping surface. The pattern may not be perfectly straight, but the common direction is the important clue. Memory cue: parallel lines on a map usually point to a common slope.

Correct answer: A. Because it separates two drainage areas

A water divide is highland that sends water in different directions. Exam tip: remember the relation between boundary and basin.

Correct answer: A. Identifying river flow direction and drainage areas

Aravalli divides water flow into different directions in some areas. Exam tip: connect highlands with water divides.

Correct answer: A. Linking Jhelum Chenab Ravi Beas Sutlej with the north-west

Jhelum Chenab Ravi Beas and Sutlej are rivers of the Indus system. Exam tip: identify rivers by region.

Correct answer: A. A large part of the main system lies in Pakistan but some major tributaries are linked with India

The Indus system is linked with the geography of both India and Pakistan. Exam tip: remember its north-western context.

Correct answer: A. After Bhagirathi and Alaknanda meet the river is called Ganga

The direct answer is A: after the Bhagirathi and Alaknanda meet at Devprayag, the combined river is called the Ganga. Devprayag is an important confluence in the Himalayan drainage system. A confluence is a place where two rivers join. Here, Bhagirathi and Alaknanda are two important headstreams. Step by step: Bhagirathi flows from the Gangotri region; Alaknanda flows through the Himalayas; they meet at Devprayag; after this meeting, the river receives the name Ganga. Option A is correct because it gives this exact geographical fact. Option B is wrong because Yamuna and Chambal do not meet at Devprayag; this is not the defining importance of the place. Option C is wrong because Brahmaputra is not renamed Jamuna at Devprayag; Jamuna is the name used for the Brahmaputra in Bangladesh. Option D is wrong because Narmada flows westward and reaches the Arabian Sea, but not at Devprayag. Do not confuse Devprayag with Prayagraj: Devprayag is associated with the naming of the Ganga, while Prayagraj is a later confluence of major rivers. Memory cue: Devprayag means “Ganga begins by name.”

Correct answer: A. It is the confluence of the Ganga and Yamuna

Prayagraj is the confluence of the Ganga and the Yamuna. It is also known as the Triveni Sangam because of the traditional belief that the Saraswati joins them invisibly. In contrast, at Devprayag the Bhagirathi and Alaknanda meet, and the river is called the Ganga thereafter. Exam tip: remember Devprayag as the point where the Ganga gets its name, and Prayagraj as the Ganga–Yamuna confluence.

Correct answer: A. They can bring water and sediment from Himalayas and increase floods in plains

Rivers like Ghaghara Gandak and Kosi bring Himalayan water and sediments. Exam tip: link floods with tributaries too.

Correct answer: A. Deposition of heavy sediment brought from the Himalayas raises and shallows the river bed, causing the river to change its course

The Kosi carries a very large load of silt, sand and other sediments from the Himalayas into the plains of Bihar. As the gradient becomes gentle in the plains, sediment is deposited on the bed, making it raised and shallow. During floods, the river may breach banks or form a new channel, leading to course shifts. Sea tides reaching the Himalayas are not responsible for this behaviour. Exam tip: remember the Kosi as the ‘Sorrow of Bihar’, associated with heavy sediment load and shifting channels.

Correct answer: A. Combined effect of high discharge high sediment and low plain slope

Direct answer: A, the combined effect of high discharge, high sediment load, and low plain slope. In Assam, the Brahmaputra carries a very large volume of water and much sediment from its mountainous catchment. When it reaches the relatively gentle plains, its flow spreads, divides into channels, and deposits sediment. Channels may shift, floodplains widen, and river islands can form, such as Majuli in the Brahmaputra system. Option A is correct because all three factors work together. Option B is wrong because desert sand alone does not explain the river’s behaviour. Option C is wrong because volcanic lava is not the main material involved. Option D is wrong because the Brahmaputra does not completely dry up in Assam. Memory cue: Brahmaputra in Assam means much water, much silt, little slope, and shifting channels.

Correct answer: A. Because the same river can have different names in different regions

Brahmaputra is called Tsangpo in Tibet and Jamuna in Bangladesh. Exam tip: connect names with route.

Correct answer: A. Division of main channel due to reduced slope and sediment deposition near the mouth

Direct answer: Option A is correct. Near the mouth of a river, the land becomes flatter, so the river loses speed and its ability to carry sediment. The Ganga and Brahmaputra bring a very large sediment load. When this sediment is deposited near the delta, the main channel becomes partly blocked or divided, and the water finds several lower paths to the sea. These smaller branches flowing away from the main river are distributaries. Option A gives both essential physical causes: reduced slope and sediment deposition. Option B describes strong erosion in the upper mountains, not the immediate cause of delta distributaries. Option C concerns the Western Ghats, which are unrelated to this delta. Option D concerns low rainfall in the Thar and is irrelevant. A distributary branches away from the main river near its mouth; a tributary joins a main river upstream. This distinction is a common exam cue.

Correct answer: A. It is a mangrove area of the Ganga-Brahmaputra delta

Sundarbans is linked with delta deposits and distributaries. Exam tip: see it not only as forest but also as delta.

Correct answer: A. Coastal width slope deposition and tidal influence

The eastern coast is known for deltas and the western coast for many estuaries. Exam tip: remember coastal slope.

Correct answer: A. They flow westward into the Arabian Sea

Most large Peninsular rivers are east-flowing but Narmada and Tapi are west-flowing. Exam tip: remember them separately.

Correct answer: A. Fault-controlled sunken course

The direct answer is A: a fault-controlled sunken course. A rift valley forms when faults, or large fractures, develop in the crust and the land block between them sinks relative to surrounding land. A river can then use this long, low depression as its channel. The Narmada is a major Indian example and flows westward through a rift valley between structural uplands. Thus its course is controlled mainly by geological structure, not by a delta or mangrove. A is correct because it describes both the fault and the lowered route. B is wrong because a delta is formed at a river mouth by deposition. C is wrong because the rift valley is the relevant feature, not a glacier-controlled source. D is wrong because mangroves and distributaries are coastal delta features. Memory cue: Narmada and Tapi are commonly linked with rift-valley drainage.

Correct answer: A. It has a large catchment and long course in Peninsular India

Godavari is one of the largest river systems of Peninsular India. Exam tip: connect Dakshin Ganga with Godavari.

Correct answer: A. They are east-flowing Peninsular rivers going towards the Bay of Bengal

These rivers are linked with deposition and deltas on the eastern coast. Exam tip: keep them separate from Narmada Tapi.