- 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) Uttar Pradesh
c) Punjab
d) Jammu and Kashmir
Ans. d) Jammu and Kashmir
Lake Wular is a natural lake in Jammu and Kashmir, famous for Avian Population.
(ii) The river Narmada has its source at:
a) Satpura
b) Brahmagiri
c) Amarkantak
d) Slopes of Western Ghats
Ans. c) Amarkantak
The Puranik name of Amarkantak is Rishika Parvat. River Narmada, Son and Mahanadi have its origin from here. Amarkantak represents the radial drainage pattern.
(iii) Which one of the following is the salt water lake?
a) Sambhar
b) Dal
c) Wular
d) Gobind Sagar
Ans. a) Lake Sambhar in Rajasthan is a salt water lake.
(iv) Which one of the following is the longest river of the Peninsular India?
a) Narmada
b) Krishna
c) Godavari
d) Mahanadi
Ans. c) Godavari
River Godavari is the second longest river after river Ganga and drains the third largest basin in India.
(v) Which one among the following rivers flows through a rift valley?
a) Mahanadi
b) Tungabhadra
c) Krishna
d) Tapi
Ans. d) Tapi
River Tapi or Tapti flows from central India towards west, to the south of river Narmada.
2. Answer the following questions briefly:
(i) What is meant by the water divide? Give an example.
Ans. Any elevated area such as mountain or upland that separates two drainage basins. Such an upland is known as the water divide eg. Ambala is located on the water divide between the Indus and the Ganga river systems.
(ii) Which is the largest river basin in India?
Ans. The Ganga basin is the largest river basin in India.
(iii) Where do the river Indus and Ganga have their origin?
Ans.
a) The headwaters of the Ganga called the Bhagirathi, is fed by the Gangotri glacier and joined by Alaknanda at Devprayag in Uttaranchal. From here it is named as River Ganga. At Haridwar the Ganga emerges from the mountains on to the plains.
b) The Indus rises in Tibet near Lake Mansarovar (from Bokhar-Chu Glacier) flows through Baltistan and Gilgit and emerges from the mountains at Attock.
(iv) Name the two headstreams of the Ganga. Where do they meet to form the Ganga?
Ans.
a) Alaknanda and Bhagirathi are the two headstreams of the river Ganga.
b) They meet at Devprayag to form river Ganga.
c) From here it is named as River Ganga at Haridwar the Ganga emerges from the mountains on to the plains.
(v) Why does the Brahmaputra in its Tibetan part have less silt, despite a longer course?
Ans.
a) The Brahmaputra River, which is known as Tsangpo in Tibet receives a very little volume of water in Tibet and it is also a cold and dry region, so it has less silt there.
b) On the other hand, this very river when enters India, it passes through such a region which receives heavy rainfall and a number of small streams.
c) As such in India it carries a large volume of water and a larger amount of silt.
(vi) Which two peninsular rivers flow through trough?
Ans. Narmada and Tapi are the two peninsular rivers which flow through the trough. A trough is a long and narrow passage of river water, mostly formed in rift valleys.
(vii) State some economic benefits of rivers and lakes.
Ans.
Rivers have been of fundamental importance throughout the human history.
Water from rivers is a basic natural resource, essential for various human activities. Rivers have attracted settlers from ancient times.
Rivers are used for irrigation, navigation, hydro-power generation etc.
3. Below are given names of a few lakes of India. Group those under two categories natural and created by human beings:
Ans.
| Natural | Created by Human Beings |
| a) Wular b) Nainital c) Barapani d) Sambhar e) Dal f) Bhimtal g) Loktak h) Chilika | a) Gobind Sagar b) Nizam Sagar c) Nagarjuna Sagar d) Rana Pratap Sagar e) Pulicat f) Hirakud
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(vii) Discuss the significant difference between the Himalayan and the peninsular rivers.
Ans.
| The Himalayan rivers | Peninsula rivers or Deccan rivers |
| a) The Himalayan rivers rise in the snow covered mountains. As such they flow throughout the year. b) The Himalayan rivers flow in levelled northern plains, therefore they are quite useful for navigation and irrigation. c) The Himalayan rivers bring with them fertile alluvial soil. Which they deposit in the Indo Gangetic plains.
d) Canals have been dug to use the water of these rivers for irrigation.
e) Many important towns and centres of trade are situated on the banks of these rivers. f) The porous soil absorbs a lot of water, which is later on used as groundwater by digging wells and tube wells for domestic and irrigation purposes.
| a) The mountain in which the Deccan rivers rise are not snow covered, hence they dry up in the summer. b) The Peninsula Rivers flow on the uneven rocky surface. Therefore they are neither navigable nor useful for irrigation. c) The peninsular rivers do not bring with them enough alluvium as the current is swift, so the deposition activity is negligible. d) As the terrain is rocky and the banks of these rivers are high, canals cannot be dug. However, dams are built to store the flood water for irrigation with the help of small channels. e) Very few important towns and centres of trade are situated on the banks of these rivers. f) The rocky soil does not absorb any water. Hence no wells can be dug. All the water flows down the sea at one and the same time. |
- Compare the east flowing and the West flowing rivers of the peninsular plateau.
Ans.
| East flowing rivers | West flowing rivers |
| a) The Mahanadi, the Godavari, Krishna and the Kaveri are the main east flowing rivers of peninsular India. b) These rivers drain in Bay of Bengal. c) These rivers make deltas at their mouth. | a) These rivers have a developed tributary system. b) Their tributaries are comparatively large in size. c) These rivers flow through not very deep channels. d) The Narmada and Tapti are the main west flowing rivers of peninsular India. e) These rivers drain in the Arabian Sea. f) These rivers enter the sea through estuaries. These rivers are devoid of developed tributary system. g) Their tributaries are quite small in size. These rivers flow in a trough or a funnel like narrow but deep channel. h) Other than River Narmada and Tapi there are many small rivers that emerge from the west of Western Ghats and flows in Arabian Sea. |
- Why are rivers important for the country’s economy?
Ans.
a) Rivers have been of fundamental importance throughout human history.
b) Water from the rivers is a basic natural resource, essential for various human activities. Therefore the river banks have attracted settlers from ancient times.
c) Early man started their settled life along the banks of river.
d) These settlements have now become big cities using rivers for irrigation.
e) Navigation and hydropower generation is of special significance.
f) Particularly to a country like India where agriculture is the major source of livelihood of the majority of its population.
Extra questions:
- Which is the main water divide in southern India?
Ans. Western Ghats is considered as the main water divide in southern India.
2. What is a Gorge?
Ans. A gorge is a deep narrow opening formed by the river in the upper course of a river. Eg – Satluj gorge, Indus gorge.
3. What is the Indus Water Treaty 1960?
Ans. It is a treaty signed between India and Pakistan in 1960. According to this treaty, India can use only 20% of the total water carried by the Indus River system.
4. Which is the largest freshwater lake of India?
Ans. Lake Wular in Jammu and Kashmir is the largest freshwater lake of India.
5. Why do the Himalayan Rivers get flooded every year? What are its advantages?
Ans. During monsoon due to heavy rainfall and large drainage basin the Himalayan rivers get flooded every year.
Advantages:
a) The floods enrich the soil of northern plains for extensive agricultural activity.
b) Various food crops and cash crops are grown in these fertile plains.
c) The population density is very high and so the industries, market and transportation system is well developed.
6. Why is the Godavari River also known as Dakshin Ganga?
Ans.
a) The Godavari River is the largest peninsular river.
b) The river basin covers parts of Maharashtra, Madhya Pradesh, Odisha and Andhra Pradesh.
c) The Godavari is joined by a number of tributaries such as the Purna, Wardha, Wainganga, Penganga, Pranhita, Manjra.
d) It is called Dakshin Ganga because of its length and large river basin.
7. Rivers constitute the most useful natural resources support the statement.
Ans.
a) Rivers provide water for survival and growth of all organisms.
b) Rivers have erected flood plains, deltas and provide fertile soil for agriculture.
c) Water from rivers is used to generating hydroelectricity.
d) Rivers serve as natural waterways for navigation.
8. Distinguish between the delta and estuary.
Ans.
| Delta | Estuaries |
| a) The triangular deposits made by the river at its mouth form delta. b) Deltas are formed in the regions of low tide and coastal plains. c) Deltas are fertile land. d) The rivers Ganga, Mahanadi, Krishna and Godavari are some of the rivers which form deltas. | a) The sharp edge at the mouth of the river, devoid of any deposits, is known as estuaries. b) The regions of high tides and rift valleys witness estuaries. c) Estuaries do not have fertile lands. d) River Narmada and Tapti form estuaries.
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