Chapter 3: Drainage
1. Choose the right answer from the four alternatives given below.
(i) In which of the following states is the Wular lake located?
(a) Rajasthan
(b) Punjab
(c) Uttar Pradesh
(d) Jammu and Kashmir
(ii) The river Narmada has its source at
(a) Satpura
(b) Amarkantak
(c) Brahmagiri
(d) Slopes of the Western Ghat
(iii) Which one of the following lakes is a saltwater lake?
(a) Sambhar
(b) Wular
(c) Dal
(d) Gobind Sagar
(iv) Which one of the following is the longest river in Peninsular India?
(a) Narmada
(b) Godavari
(c) Krishna
(d) Mahanadi
(v) Which one amongst the following rivers flows through a rift valley?
(a) Mahanadi
(b) Krishna
(c) Tungabhadra
(d) Tapi
2. Answer the following questions briefly.
(i) What is meant by a water divide? Give an example.
Answer: An elevated area that separates two drainage basins is called an upland or a water divide. It acts as a boundary between different river systems. For instance, the water divide between the Indus and Ganga River Systems serves as a clear example.
(ii) Which is the largest river basin in India?
Answer: The Ganga River Basin is the largest river basin in India.
(iii) Where do the rivers Indus and Ganga have their origin?
Answer: Indus River originates near Manasarovar Lake in Tibet, while the Ganga River originates from the Gangotri glacier in Uttarakhand.
(iv) Name the two headstreams of the Ganga. Where do they meet to form the Ganga?
Answer: The Ganga River is formed by the confluence of two headstreams, the Alaknanda and the Bhagirathi. They meet at Devprayag to form the Ganga.
(v) Why does the Brahmaputra in its Tibetan part have less silt, despite a longer course?
Answer: In Tibet, the Ganga River carries a smaller volume of water and less silt due to the cold and dry conditions. However, as it passes through India, where there is high rainfall, the river carries a large volume of water and a significant amount of silt.
(vi) Which two Peninsular rivers flow through a trough?
Answer: Narmada and Tapi are the two Peninsular rivers that flow through a rift valley.
(vii) State some economic benefits of rivers and lakes.
Answer: Rivers have played a crucial role in human history as they provide a vital natural resource, water, which is essential for various human activities. Settlements have been established along riverbanks since ancient times due to their importance. Rivers are especially significant for activities such as irrigation, navigation, and hydropower generation, which are essential for countries like India where agriculture is a major livelihood source for the majority of the population.
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
Natural Lakes
- Wular
- Dal
- Nainital
- Bhimtal
- Loktal
- Chilika
- Pulicat
- Sambhar
- Barapani
Human-made Lakes
- Gobind Sagar
- Rana Pratap Sagar
- Nizam Sagar
- Nagarjuan Sagar
- Hirakud
4. Discuss the significant difference between the Himalayan and the Peninsular rivers.
Answer:
Himalayan Rivers:
- Perennial rivers that flow throughout the year.
- Receive water from rain and snowfall in the Himalayan region.
- Have a steady flow of water throughout the year.
Peninsular Rivers:
- Seasonal rivers that depend on rainfall.
- Experience fluctuations in water flow based on the monsoon season.
- Can dry up during dry seasons or low rainfall periods.
5. Compare the east-flowing and the west-flowing rivers of the Peninsular plateau.
Answer:
West Flowing Rivers:
- Two long west flowing rivers: Narmada and Tapi.
- Flow into the Arabian Sea.
- Have fewer tributaries.
- Form estuaries.
- Carry lesser sediments compared to east flowing rivers.
East Flowing Rivers:
- Several major rivers like Mahanadi, Cauvery, Godavari, Krishna, etc.
- Flow into the Bay of Bengal.
- Have numerous tributaries.
- Form deltas.
- Carry larger sediments compared to west flowing rivers.
6. Why are rivers important for the country’s economy?
Answer: Rivers have played a crucial role in human history, providing a vital water resource for various human activities. Riverbanks have been attractive settlement areas since ancient times, leading to the growth of major cities. The utilization of rivers for irrigation, navigation, and hydropower generation holds great importance, especially in countries like India, where agriculture is a primary livelihood for many people. Rivers have been instrumental in supporting agricultural practices and sustaining communities over time.
