The NCERT Solutions for Class 9 Social Science Geography Chapter 3 Drainage provides answers to questions related to India’s drainage system. The chapter focuses on the rivers of the Himalayas, peninsular rivers, lakes, the significance of rivers in the economy, and river pollution.
To find the solutions to all six questions in the exercise, refer to the NCERT Solutions for Class 9 Geography Chapter 3 section below. These solutions are aligned with the content of the NCERT book and can be valuable resources for CBSE exam preparation.
1. Choose the right answer from the four alternatives given below.
(i) In which of the following states is Wular Lake located?
(a) Rajasthan
(c) Punjab
(b) Uttar Pradesh
(d) Jammu and Kashmir
Ans. Jammu and Kashmir
(ii) The river Narmada has its source at
(a) Satpura
(c) Amarkantak
(b) Brahmagiri
(d) Slopes of the Western Ghats
Ans. Amarkantak
(iii) Which one of the following lakes is a saltwater lake?
(a) Sambhar
(c) Wular
(b) Dal
(d) Gobind Sagar
Ans. Sambhar
(iv) Which one of the following is the longest river of the Peninsular India?
(a) Narmada
(c) Godavari
(b) Krishna
(d) Mahanadi
Ans. Godavari
(v) Which one amongst the following rivers flows through a rift valley?
(a) Mahanadi
(c) Krishna
(b) Tungabhadra
(d) Tapi
Ans. Tapi
2. Answer the following questions briefly.
(i) What is meant by a water divide? Give an example.
Ans. An upland refers to an elevated area, such as a mountain or upland region, that acts as a division between two drainage basins. It is also commonly referred to as a water divide. One notable example of a water divide is the elevated region separating the Indus and Ganga River Systems.
(ii) Which is the largest river basin in India?
Ans. The largest river basin in India is the Ganga basin (Ganga-Brahmaputra-Meghna basin), which covers an area of approximately 1,086,000 square kilometers. It is a transboundary basin, spanning parts of India, Nepal, Bangladesh, and China. The basin is home to over 500 million people, making it the most populated river basin in the world.
(iii) Where do the rivers Indus and Ganga have their origin?
Ans. The river Indus originates in the Tibetan Plateau in the vicinity of Lake Mansarovar in the western region of the Himalayas. It flows through the present-day regions of Tibet (China), India, and Pakistan before emptying into the Arabian Sea.
The river Ganga (Ganges) originates in the Gangotri Glacier, which is located in the Uttarkashi district of the Indian state of Uttarakhand. The glacier lies in the western Himalayas, near the India-China border. From its source, the Ganga flows through northern India, passing through several states such as Uttarakhand, Uttar Pradesh, Bihar, and West Bengal, before finally reaching its delta in Bangladesh and emptying into the Bay of Bengal.
(iv) Name the two headstreams of the Ganga. Where do they meet to form the Ganga?
Ans. The two headstreams of the Ganga are the Bhagirathi and the Alaknanda.
The Bhagirathi River originates from the Gangotri Glacier in the Uttarkashi district of Uttarakhand, India. It is considered the main and longer headstream of the Ganga.
The Alaknanda River originates from the Satopanth Glacier, also located in Uttarakhand. It joins several other rivers and streams along its course, including the Mandakini and Nandakini, before converging with the Bhagirathi River.
The meeting point of the Bhagirathi and Alaknanda rivers is known as Devprayag, located in the Tehri Garhwal district of Uttarakhand. At Devprayag, the two rivers merge and form the Ganga River, which continues its journey downstream through the plains of northern India.
(v) Why does the Brahmaputra in its Tibetan part have less silt, despite a longer course?
Ans. The river, originating in Tibet, carries a lesser volume of water and silt due to the cold and arid nature of the region. However, as it traverses through India, where rainfall is abundant, the river undergoes a significant transformation. Here, it receives a substantial influx of water and accumulates a considerable amount of silt, resulting in a pronounced increase in both volume and sediment content.
(vi) Which two Peninsular rivers flow through a trough?
Ans. Narmada and Tapi, two rivers of the Indian Peninsula, flow through a geological formation known as a trough
(vii) State some economic benefits of rivers and lakes.
Ans. Rivers hold immense significance in the annals of human history, serving as a crucial lifeline. The water they provide is a fundamental natural resource, vital for a myriad of human endeavors. Consequently, riverbanks have drawn settlers since ancient times. The utilization of rivers for irrigation, transportation, and hydroelectric power generation carries profound importance, particularly in countries like India, where agriculture sustains a significant portion of the population’s livelihood.
3. Below are given names of a few lakes of India. Group them under two categories – natural and created by human beings.
(a) Wular (b) Dal (c) Nainital (d) Bhimtal (e) Gobind Sagar (f) Loktak (g) Barapani (h) Chilika (i) Sambhar (j) Rana Pratap Sagar (k) Nizam Sagar (l) Pulicat (m) Nagarjuna Sagar (n) Hirakund
Ans.
Natural Lakes : Wular, Dal, Nainital, Bhimtal, Loktal, Chilika, Pulicat, Sambhar, Barapani
Man-Made Lakes: Gobind Sagar, Rana Pratap Sagar, Nizam Sagar, Nagarjuan Sagar, Hirakud
4. Discuss the significant difference between the Himalayan and the Peninsular rivers.
Ans. Himalayan rivers and Peninsular rivers in India exhibit significant differences in their characteristics, origins, and geological formations. Here are some key distinctions between the two:
Origin and Geological Formation-
Himalayan Rivers: These rivers originate from the Himalayan mountain range, which is the youngest and tallest mountain range in the world. The Himalayan rivers are mainly fed by melting glaciers and snow, resulting in their perennial nature.
Peninsular Rivers: The Peninsular Rivers, also known as the Deccan Rivers, flow across the Peninsular Plateau of India. They are older and have their origin within the Indian Peninsula, far away from the Himalayas. These rivers primarily depend on seasonal rainfall, making them more seasonal in nature.
Course and Topography-
Himalayan Rivers: The Himalayan rivers have a steep gradient and flow swiftly through narrow valleys and gorges. They are characterized by their turbulent and powerful currents, which lead to the formation of several waterfalls and rapids along their course.
Peninsular Rivers: The Peninsular Rivers have a relatively gentler slope and meander through the flat terrain of the Peninsular Plateau. They often form broad river valleys, deltas, and estuaries as they approach the coastal regions.
Water Discharge and Sediment Load-
Himalayan Rivers: Due to their origin in the Himalayas, these rivers receive substantial water from snowmelt and glacial sources. They have a higher water discharge, especially during the summer months, and carry a significant amount of sediment due to the erosion of the mountains.
Peninsular Rivers: As the Peninsular rivers primarily depend on monsoon rains, their water discharge is more variable, with pronounced fluctuations between wet and dry seasons. The sediment load in Peninsular rivers is relatively lower compared to Himalayan rivers.
Hydroelectric Potential-
Himalayan Rivers: The steep gradient and high water discharge of the Himalayan rivers make them ideal for the development of hydroelectric power projects. Major dams and power stations are constructed on rivers like the Ganga, Brahmaputra, and Indus.
Peninsular Rivers: While Peninsular rivers also have hydroelectric potential, their relatively lower water discharge and flat terrain make them more suitable for smaller-scale projects rather than large dams.
5. Compare the east-flowing and the west-flowing rivers of the Peninsular Plateau.
Ans. The east-flowing and west-flowing rivers of the Peninsular Plateau in India exhibit distinct characteristics and follow different drainage patterns. Here is a comparison between the two:
West flowing rivers-
- Narmada and Tapi are the only west-flowing rivers in the Peninsular Plateau.
- These rivers have a lesser number of tributaries.
- These rivers flow into the Arabian Sea.
- They carry lesser sediments.
- They form estuaries.
East flowing rivers-
- Mahanadi, Cauvery, Godavari, Krishna are the major East Flowing rivers in the Peninsular Plateau.
- These rivers have many tributaries.
- These rivers flow into the Bay of Bengal.
- They carry larger sediments than West flowing rivers.
- They form Deltas.
6. Why are rivers important for the country’s economy?
Ans. Rivers have played a pivotal role in shaping human history, offering an invaluable natural resource: water. Water sourced from rivers is a fundamental necessity, and crucial for a wide range of human activities. As a result, riverbanks have enticed settlers since ancient times, evolving into bustling cities today. Harnessing rivers for irrigation, transportation, and hydropower generation holds exceptional importance, especially in countries like India, where agriculture serves as the primary livelihood for a significant portion of the population.
Map Skills-
(i) On an outline map of India mark and label the following rivers: Ganga, Satluj, Damodar, Krishna, Narmada, Tapi, Mahanadi, and Brahmaputra.
(ii) On an outline map of India mark and label the following lakes: Chilika, Sambhar, Wular, Pulicat, Kolleru.
Ans:
