Test: Drainage - 1 - UPSC MCQ

It rises on Brahmagiri Hill of the Western Ghats in southwestern Karnataka state, flows in a southeasterly direction for 475 miles (765 km) through the states of Karnataka and Tamil Nadu, and descends the Eastern Ghats in a series of great falls.

The definition of a water divide is A) An upland that separates two drainage basins. It refers to a ridge or elevated area of land that acts as a boundary between two adjacent drainage basins, determining the direction in which water flows towards different river systems.

Most of the Peninsular rivers in India are not perennial; they are seasonal. These rivers primarily depend on rainfall and have water during the monsoon season. Unlike the Himalayan rivers, which are fed by snowmelt and rainfall and therefore flow throughout the year, Peninsular rivers rely on the monsoon rains, making their flow highly seasonal.

The statement "D) Its tributaries are the Tungabhadra and Musi" is not correct. The Narmada River's tributaries include the Tawa, Barna, and Banjar, but not the Tungabhadra and Musi, which are tributaries of the Krishna River.

Himalayan rivers in India are mainly perennial, meaning they have water throughout the year due to receiving water from rain and melted snow from the mountains. This consistent water flow supports their long courses and intensive erosional activities.

The Himalayan rivers exhibit the following characteristics:

• (i) They have water throughout the year: Himalayan rivers are perennial, meaning they have a continuous flow of water throughout the year. This is due to their sources in the high-altitude glaciers and snowmelt, along with monsoon rains.
• (iv) They perform intensive erosional activity in their upper courses: In their upper courses, Himalayan rivers flow rapidly through steep mountainous regions, leading to significant erosion. This erosion transports large amounts of sediment downstream.

Statement (ii) is false because Himalayan rivers actually form well-developed deltas. These rivers carry substantial sediment loads, which are deposited in the lower courses, forming extensive and fertile deltas, such as the Ganges-Brahmaputra Delta.

Statement (iii) is false because Himalayan rivers originate from the Himalayan mountain range, not the Western Ghats. The Western Ghats are a mountain range located in the western part of southern India, while the Himalayas are in the northern part of the Indian subcontinent.

The total length of the River Ganga drainage basin is approximately A) 2500 km. This basin covers a vast area spanning across multiple states in India, including Uttarakhand, Uttar Pradesh, Bihar, and West Bengal, before ultimately draining into the Bay of Bengal.

The river Indus rises in Tibet, near Lake Mansarowar.

The river Narmada has its source at Amarkantak, a prominent pilgrimage site located in the Maikal Hills of the Satpura Range. It originates from the Narmada Kund, which is considered the exact source of the river.

• Option A is correctly matched. The Ganga emerges from the mountains onto the plains at Haridwar.
• Option B is incorrect because the source of the Brahmaputra is near Mansarowar Lake in Tibet, not the Yamunotri Glacier.
• Option C is incorrect because Devaprayag is the confluence of Bhagirathi and Alaknanda, which form the Ganga, not the Indus.
• Option D is incorrect because the Narmada originates in the Amarkantak hills in Madhya Pradesh, not Tibet.

The Ganges river has the largest basin in India, encompassing a vast area and playing a crucial role in the country's drainage system.

• Assertion (A): The Brahmaputra is marked by huge deposits of silt on its bed, causing the riverbed to rise. This is true. The Brahmaputra carries a significant amount of silt, which deposits on the riverbed, causing it to rise over time.

• Reason (R): The Brahmaputra passes through a region of high rainfall in India, resulting in the river carrying a large volume of water and considerable silt. This is also true. The Brahmaputra flows through areas that receive heavy rainfall, contributing to the large volume of water and silt it carries.

• Explanation: Although both the Assertion and the Reason are true, the Reason does not directly explain why the Brahmaputra is marked by huge deposits of silt. The high rainfall contributes to the river's volume and silt load, but it does not directly explain the specific issue of the riverbed rising due to silt deposits. Therefore, the correct answer is Option B: both Assertion and Reason are true, but the Reason is not the correct explanation of the Assertion.

The Ganga River System is renowned for forming a distributary known as Bhagirathi-Hooghly, which flows southwards through the deltaic plains to the Bay of Bengal, while the mainstream continues its journey into Bangladesh and joins the Brahmaputra downstream.

Option A: The Godavari Basin - Rises from the highlands of Chhattisgarh
Incorrect: The Godavari rises from the slopes of the Western Ghats in the Nasik district of Maharashtra.

Option B: The Krishna Basin - Flows into the Arabian Sea
Incorrect: The Krishna river flows into the Bay of Bengal.

Option C: The Mahanadi Basin - Flows through Odisha to reach the Bay of Bengal
Correct: The Mahanadi river rises in the highlands of Chhattisgarh and flows through Odisha to reach the Bay of Bengal.

Option D: The Kaveri Basin - Forms the largest waterfall in India
Incorrect: The Kaveri river forms the Shivasamudram Falls, which is the second biggest waterfall in India, not the largest. Therefore, the correctly matched pair is Option C: The Mahanadi Basin - Flows through Odisha to reach the Bay of Bengal.

• The Godavari river is referred to as Dakshin Ganga because of its extensive length and drainage basin, making it a significant river in India akin to the Ganges in the north.
• This river originates in the Western Ghats and flows into the Bay of Bengal, playing a crucial role in the irrigation and agriculture of the regions it traverses.

The drainage basin is called the region drained by a single river system. The drainage basin acts as a funnel by collecting all the water within the area covered by the basin and channeling it to a single point. Amazon river is the world's largest drainage basin.

The saltwater lake of Rajasthan is B) Sambhar Lake. It is the largest saline lake in India, located in the Ajmer district of Rajasthan, and it is known for its salt production and unique ecosystem.

The Wular Lake is located in Jammu and Kashmir. It is the largest freshwater lake in India and is situated in the Kashmir Valley, near the town of Sopore.

The Guru Gobind Sagar Lake differs from the rest in the group because it is a reservoir formed by the Bhakra Dam on the Sutlej River, whereas the other lakes mentioned are natural freshwater lakes.

Option A: The Indus - Peninsular River:
 Incorrect: The Indus is a Himalayan river, not a Peninsular river. It originates from the north of the mountain ranges and is perennial.

Option B: The Ganges - Perennial River
Correct: The Ganges is a Himalayan river, and it is perennial, meaning it has water throughout the year due to rain and melting snow from the mountains.

Option C: The Godavari - Seasonal River:
Incorrect: This is incorrect because although the Godavari is a Peninsular river, it is not typically classified as a seasonal river. It generally has a significant flow throughout the year, although it is dependent on rainfall.

Option D: The Brahmaputra - Peninsular River:
Incorrect: This is incorrect because the Brahmaputra is also a Himalayan river, not a Peninsular river. It originates from the north of the mountain ranges and is perennial. Therefore, the correctly matched pair is Option B: (b) The Ganges - Perennial River.