NCERT Solutions for Drainage Class 9 Question Answer provide answers to questions related to the drainage system of India, including the Himalayan rivers, peninsular rivers, lakes, and the role of rivers in the economy and river pollution. These solutions are based on the NCERT textbook and are intended to help students prepare for their CBSE exams.
Drainage Class 9 Question Answer
1. Choose the right answer from the four alternatives given below.
1. In which of the following states is the Wular lake located?
a. Rajasthan
b. Uttar Pradesh
c. Punjab
d. Jammu and Kashmir
2. The river Narmada has its source at
a. Satpura
b. Brahmagiri
c. Amarkantak
d. Slopes of the Western Ghats
3. Which one of the following lakes is a salt water lake?
a. Sambhar
b. Dal
c. Wular
d. Gobind Sagar
4. Which one of the following is the longest river of the Peninsular India?
a. Narmada
b. Krishna
c. Godavari
d. Mahanadi
5. Which one amongst the following rivers flows through a rift valley?
a. Mahanadi
b. Tungabhadra
c. Krishna
d. Tapi
2. Answer the following questions briefly.
a. What is meant by a water divide? Give an example.
b. Which is the largest river basin in India?
c. Where do the rivers Indus and Ganga have their origin?
d. Name the two headstreams of the Ganga. Where do they meet to form the Ganga?
e. Why does the Brahmaputra in its Tibetan part have less silt, despite a longer course?
f. Which two Peninsular rivers flow through trough?
g. State some economic benefits of rivers and lakes.
Answer –
a. What is meant by a water divide? Give an example.
Answer – A water divide is a ridge or high point that separates two watersheds or drainage basins. Water on one side of the divide flows in one direction, while water on the other side flows in another direction.
An example of a water divide in India is the Himalayan mountain range, which forms a natural barrier between the Indus and Ganges river systems. The Himalayas act as a water divide, with rivers on the western side of the mountains flowing into the Arabian Sea and rivers on the eastern side flowing into the Bay of Bengal. The Himalayas are the highest mountain range in the world and are home to many of the highest peaks, including Mount Everest.
b. Which is the largest river basin in India?
Answer – The Ganges River Basin is the largest river basin in India, covering an area of about 1,086,000 square kilometers. It is located in northern India and is home to about 40% of India’s population.
c. Where do the rivers Indus and Ganga have their origin?
Answer – The Indus River originates in the Tibetan plateau in China, near the city of Lhasa. It flows through the Ladakh region of India and into Pakistan, where it eventually empties into the Arabian Sea.
The Ganges River has its source in the western Himalayas in the Indian state of Uttarakhand. It begins at the confluence of the Alaknanda and Bhagirathi rivers, which rise from the glaciers of the Gangotri and Yamunotri ranges, respectively.
d. Name the two headstreams of the Ganga. Where do they meet to form the Ganga?
Answer – The Alaknanda and Bhagirathi rivers meet at a place called Devprayag in the Indian state of Uttarakhand, where they combine to form the Ganges River.
e. Why does the Brahmaputra in its Tibetan part have less silt, despite a longer course?
Answer – The Brahmaputra River, which is known as the Yarlung Tsangpo in its upper reaches in Tibet, has a relatively low amount of silt because it flows through a relatively dry and arid region. The Tibetan Plateau, where the Yarlung Tsangpo has its source, is a high-altitude plateau with very little rainfall, so there is not a lot of water available to carry silt and other sediment downstream.
In addition, the Yarlung Tsangpo flows over a bed of hard, rocky terrain, which does not allow much of the sediment carried by the river to be deposited. As a result, the Yarlung Tsangpo carries relatively little silt compared to other major rivers, despite its long course.
f. Which two Peninsular rivers flow through trough?
Answer – There are several peninsular rivers in India that flow through troughs, but the two most notable examples are the Narmada and the Tapti.
g. State some economic benefits of rivers and lakes.
Answer – Rivers and lakes provide a number of economic benefits to the regions they flow through or are located in. Some of the economic benefits of rivers and lakes include:
- Water supply: Rivers and lakes are a source of fresh water for drinking, irrigation, and industrial use.
- Hydroelectric power: Rivers and lakes can be used to generate hydroelectric power, which is a clean and renewable source of energy.
- Transportation: Rivers and lakes can be used for transportation of people and goods, either by boat or barge.
- Fishing: Rivers and lakes are home to a variety of fish species, which can be harvested for food or other purposes.
- Recreational activities: Rivers and lakes are popular destinations for recreational activities such as boating, swimming, and fishing, which can generate tourism revenue for local communities.
- Flood control: Rivers and lakes can help to regulate flood waters and protect against flooding, which can help to reduce damage to property and infrastructure.
- Agriculture: Rivers and lakes can provide irrigation water for agriculture, which is vital for food production in many regions.
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
Answer –
Natural Lakes:
- Wular – Wular Lake is a natural freshwater lake located in the Indian state of Jammu and Kashmir. It is the largest freshwater lake in India.
- Dal – Dal Lake is a natural lake located in the city of Srinagar, in the Indian state of Jammu and Kashmir.
- Nainital – Nainital Lake is a natural freshwater lake located in the Indian state of Uttarakhand.
- Bhimtal – Bhimtal Lake is a natural freshwater lake located in the Indian state of Uttarakhand.
- Loktal – Loktal Lake is a natural freshwater lake located in the Indian state of Manipur.
- Chilika – Chilika Lake is a large, brackish water lagoon located in the Indian state of Odisha. It is the largest coastal lagoon in India and is home to a diverse range of flora and fauna.
- Pulicat – Pulicat Lake is a large, brackish water lagoon located on the border between the Indian states of Andhra Pradesh and Tamil Nadu. It is the second largest brackish water lagoon in India.
- Sambhar – Sambhar Lake is a large, saline lake located in the Indian state of Rajasthan. It is the largest inland saltwater lake in India and is an important source of salt for the country.
Man-made lakes
- Gobind Sagar – Gobind Sagar Lake is a man-made lake located in the Indian state of Himachal Pradesh. It was created by the construction of the Bhakra Dam on the Sutlej River in the 1960s.
- Rana Pratap Sagar – Rana Pratap Sagar Lake, also known as the Rawatbhata Dam Reservoir, is a man-made lake located in the Indian state of Rajasthan. It was created by the construction of the Rawatbhata Dam on the Chambal River in the 1970s.
- Nizam Sagar – Nizam Sagar Lake is a man-made lake located in the Indian state of Telangana. It was created by the construction of the Nizam Sagar Dam on the Manjira River in the 1950s.
- Nagarjuan Sagar – Nagarjuna Sagar Lake is a man-made lake located in the Indian state of Telangana. It was created by the construction of the Nagarjuna Sagar Dam on the Krishna River in the 1960s.
- Hirakud – Hirakud Dam is a dam and reservoir located on the Mahanadi River in the Indian state of Odisha. The dam was constructed in the 1950s for the purpose of hydroelectric power generation and flood control.
- Barapani – Barapani Lake, also known as Umiam Lake, is a man-made lake located in the Indian state of Meghalaya.
4. Discuss the significant difference between the Himalayan and the Peninsular rivers.
Answer – There are several significant differences between the Himalayan and the peninsular rivers in India:
- Origin: The Himalayan rivers have their source in the Himalayas, the highest mountain range in the world, while the peninsular rivers have their source in the Deccan Plateau, which is a large plateau located in southern and central India.
- Course: The Himalayan rivers have a longer course compared to the peninsular rivers because they have to travel a longer distance from their source to their destination. The Himalayan rivers flow from the Himalayas to the plains, while the peninsular rivers flow from the Deccan Plateau to the coast.
- Water volume: The Himalayan rivers have a higher water volume compared to the peninsular rivers because they receive more rainfall and have a larger catchment area. The Himalayan rivers are also fed by glacial meltwater, which contributes to their high water volume.
- Flooding: The Himalayan rivers are prone to flooding because they have a high water volume and are fed by heavy rainfall and glacial meltwater. The peninsular rivers, on the other hand, are not prone to flooding because they have a lower water volume and receive less rainfall.
- Valley formation: The Himalayan rivers have formed deep, wide valleys because they flow through hard rock formations and have a high water volume. The peninsular rivers, on the other hand, have formed narrow, shallow valleys because they flow through softer rock formations and have a lower water volume.
5. Compare the east flowing and the west flowing rivers of the Peninsular plateau.
Answer – There are several differences between the east flowing and the west flowing rivers of the Peninsular plateau in India:
- Location: The east flowing rivers are located in the eastern part of the Peninsular plateau, while the west flowing rivers are located in the western part of the plateau.
- Direction of flow: As their names suggest, the east flowing rivers flow towards the east, while the west flowing rivers flow towards the west.
- Source: The east flowing rivers have their source in the eastern Ghats, a mountain range in eastern India, while the west flowing rivers have their source in the western Ghats, a mountain range in western India.
- Course: The east flowing rivers have a shorter course compared to the west flowing rivers because they do not have to travel as far from their source to their destination. The east flowing rivers flow from the eastern Ghats to the Bay of Bengal, while the west flowing rivers flow from the western Ghats to the Arabian Sea.
- Water volume: The east flowing rivers have a lower water volume compared to the west flowing rivers because they receive less rainfall and have a smaller catchment area.
- Flooding: The east flowing rivers are not prone to flooding because they have a lower water volume and receive less rainfall. The west flowing rivers, on the other hand, are prone to flooding because they have a higher water volume and are fed by heavy rainfall.
6. Why are rivers important for the country’s economy?
Answer – Rivers are important for the country’s economy for several reasons:
- Water supply: Rivers are a vital source of fresh water for drinking, irrigation, and industrial use.
- Hydroelectric power: Rivers can be used to generate hydroelectric power, which is a clean and renewable source of energy.
- Transportation: Rivers can be used for transportation of people and goods, either by boat or barge.
- Fishing: Rivers are home to a variety of fish species, which can be harvested for food or other purposes.
- Recreational activities: Rivers are popular destinations for recreational activities such as boating, swimming, and fishing, which can generate tourism revenue for local communities.
- Flood control: Rivers can help to regulate flood waters and protect against flooding, which can help to reduce damage to property and infrastructure.
- Agriculture: Rivers can provide irrigation water for agriculture, which is vital for food production in many regions.