Chapter 3 Drainage | Geography | CBSE Class 9th | Solved Exercises

Question 1. Choose the right answer from the four alternatives given below:

(i) Which one of the following describes the drainage patterns resembling the branches of a tree?
(a) Radial
(b) Dendritic
(c) Centrifugal
(d) Trellis

Answer : (b) Dendritic



(ii) In which of the following states is the Wular lake located?
(a) Rajasthan
(b) Uttar Pradesh
(c) Punjab
(d) Jammu and Kashmir

Answer : (d) Jammu and Kashmir


(iii) The river Narmada has its source at
(a) Satpura
(b) Brahmagiri
(c) Amarkantak
(d) Slopes of the Western Ghats

Answer : (c) Amarkantak


(iv) Which one of the following lakes is a salt water lake? the following Union Territories of India you will be going to-
(a) Sambhar
(b) Dal
(c) Wular
(d) Gobind Sagar

Answer : (a) Sambhar


(v) Which one of the following is the longest river of the Peninsular India?
(a) Narmada
(b) Krishna
(c) Godavari
(d) Mahanadi

Answer: (c) Godavari


(vi) Which one amongst the following rivers flows through a rift valley?
(a) Mahanadi
(b) Tungabhadrabr
(c) Krishna
(d) Tapi

Answer : (d) Tapi

Question 2. Answer the following questions briefly.

Question (i). What is meant by a water divide? Give an example.

Answer : Water-divide is a line of high land where stream on side flow into a different but streams on the other side flow into different river e.g, Western Ghats in Peninsular India.

Question (ii). Which is the largest river basin in India?

Answer : Ganga-Yamuna doab and basin.

Question (iii). Where do the rivers Indus and Ganga have their origin?

Answer :

• The Bhagirathi is called the headwaters of the Ganga which is fed by the Gangotri Glacier. it is Joined by the Alaknanda at Devprayag Uttranchal. The Ganga emerges from mountains on to plains at Haridwar.
• The indus orignate from a peak nearby Mansarovar lake in Kailash range of Greater Himalayas. It flows down from an altitude of 5000 mts. from sea level.

Question (iv). Name the two head streams of the Ganga. Where do they meet to form the Ganga?

Answer : These are (a) Bhagirathi, (b) Alaknanda. These two river meet at Devpryag to form of Ganga.

Question (v). Why does the Brahmaputra in its Tibetan part have less silt, despite a longer course?

Answer : Most of course of Brahmputra lies in Tibet. It enters India in Arunachal Pradesh. In Tibet, The volume of water river is less and has less silt. But in India the rivers has large volume of water and more silt. The river has a braided channel in Assam.

(vi). Which two Peninsular rivers flow through trough?

Answer: Narmada and Tapi.

(vii). State some economic benefits of rivers and lakes.

Answer: Roles of Rivers and Lakes in the Economy

• Cultural Importance- Rivers have been of fundamentals importance throughout the human history. the areas along the banks of rivers have witnessed great cultural and economic progress since ancient times. Rivers are an integral part of our folklore and folk songs.
• A Natural Resource- Water from the rivers is a basic natural resource, essential for human, agricultural and industrial activities.
• Agricultural Areas- Rivers and their associated alluvial soils provide the most productive agricultural lands of the country. The Ganga, the Kaveri and other deltas have traditionally been tne rice growing areas. An agriculture dependent on the vagaries of the monsoon, irrigation from rivers have been the backbone of the development of Indian agriculture.
• Settlements- The valley contain dense and concentrated settlements. Most of the large cities are located on rivers. Not only do rivers provide us with essential water supplies, but they also receive, dilute and tranport wastes from settlements.
• Industrial Development- Industrial development has flourished along  side  rivers as many industrial process rely on water- as a raw material, as a coolant and for the generation of hydroelectricity.
• Transportation- Rivers provide primary channels of inland transportation, not only directly in the form of navigable waterways, but also indirectly through their valleys, where roads, railway lines and other routes are built.
• Tourism- Recreation, tourist promotion and fishing are also being developed along water fronts.

Importance of Lakes Lakes are great value of man

• A lake helps to regulate the flow of river.
• During heavy rainfall, it prevents flooding and during the dry season, it helps to maintain an even flow of water.
• Lakes can also be used source of water.
• Lakes are valuable source of water.
• They moderate the climate of the surrounding, maintain the aquatic ecosystem natural beauty, help develop tourism and provide recreation.

Question 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) Vembnad	(l) Nizam Sagar
(m) Pulicat	(n) Nagarjuna Sagar
(o) Gandji Sagar	(p) Hirakund

Answer :
Natural lakes : (a) Wular (b) Dal (d) Bhimtal (f) Loktak (g) Barapani (h) Chilika (i) Sambhar (k) Vembnad (l) Pulicat
Man-made lakes : (e) Gobind Sagar (j) Rana Pratap Sagar (l) Nizam Sagar (o) Gandji Sagar (m) Pulicat

Question 4. Discuss the significant difference between the Himalayan and the Peninsular rivers.
Answer :

Himalyan Rivers	Rivers of the Peninsula
1. These rivers rise from the snow covered Himalyas hence these are perennial.	1. These Peninsular rivers are seasonal. They get supply of water from summer rainfall.
2. These rivers do not have any waterfalls. Hence, these are not useful for generation of water power.	2. These rivers make waterfalls and cataracts on the plateau. hence, these are useful for hydro-electric projects.
3. The Himalayan rivers have large basins and extensive catchment areas. Therefore these have a large volume of water.	3. The Peninsular rivers have small basins and small catchment areas. Therefore these do not have large volume of water.
4. These rivers flow over plains. Therefore these are useful for irrigation and navigation.	4.e These rivers flow on rocky areas and are not used for irrigation and navigation.
5. These rivers pass through deep gorges before entering the plains and have meandering course on plains.	5. These rivers flow through shallow river valley having straight courses.
6. These rivers from vast alluvial plains by depositing sediments.	6. These rivers do not bringh fertile alluvium and do not form alluvial plains.
7. Many important towns hve been developed on the courses of these rivers.	7. Very few towns have been developed on the banks of these rivers.

Question 5. Compare the east flowing and the west flowing rivers of the Peninsular plateau.
Answer : The East flowing and the West flowing rivers of Peninsular India are: Mahanadi, Godavari, Krishna and Kaveri are East flowing rivers. The Narmada and Tapi West flowing rivers

East flowing rivers	West flowing rivers
1. The rivers are snow and rain fed. This is the reason, these are called perennial rivers, e.g, the Ganga, the Indus and the Brahmaputra.	1. Most of the rivers are rain fed and as result, remain dry or dull during summer and winter dry season.
2. Most of the rivers flow of tghe plain land and there is proper navigation and irrigation facility.	2.These rivers flow on the plateau and navigation is not always possible. Only in some parts irrigation is possible..
3. The rivers are tender aged and new. they can change their directions.	3. The rivers are old. they cannot their directions.
4. There are many ox-boy lakes and islands at mougth of these rivers	4. There are ample islands but no lakes.
5. There are many branches and tributaries of these rivers.	5. There are few branches of these rivers.
6. Himalayan rivers are very lengthy. There are towns, mega-cities at their banks.	6. Peninsular river has not so long as the Himalayan rivers are. There are few towns we see at their banks.
7. Himalayan rivers are mighty at their origin in and carry mud and silt in large quantum with them down ward and spread the same on the Northern plains.	7. Peninsular block being a table land, there are rocks made of igneous material and the oldest on either side of the rivers. less silt and alluvium therefore, these carry with them.
8. The Himalayan rivers provide ample scope of navigation, irrigation, channelising (i.e canal digging etc.) to human beings on the plains, specially because these revers flow on the surface.	8. The Peninsular rivers make gorge, rift valleys, canyons. Hence, canal digging proves a costly. There is hardly navigation possible through these rivers.

Question 6. Why are rivers important for the country’s economy?
Answer : Rivers have been of fundamental importance throughout the human history. Water from the rivers is a basic natural resource, essential for various human activities. Therefore, the river banks have attracted settlers from ancient times. These settlements have now become big cities. In India many cities are based on the banks of a rivers. Using rivers for irrigation, navigation, hydro-power generation is of special significance – particularly to a country like India, where agriculture is the major source of livelihood of the majority of its population

Facts About Drainage - The river system:

• The Drainage System: (i) Rivers of Northern India. (ii) Rivers of Peninsular India
• Rivers Drain into two areas: (i) Bay of Bengal (ii) Arabian Sea.
• Rivers- provide multiple resources: Basis of irrigation, water power generation, island water transport, domestic and industrial water supply.
• Main Rivers of Northern India: Indus Ganga and Brahmputra (Perennial).
• Mains Rivers of Northern India: Mahanadi, Godavari and Krishna eand Cauvery (Seasonal).
• Trans Himalyan: Indus, Sutlej, Brahmputra Rivers.
• Vindhyan Ranges: Water divide between rivers of Northern plains and peninsular India.
• The largest delta: Sunderbans (Ganga- Brahmputra.
• Lagoons: Pulicat and Chilka lakes.
• 'Sorrow of Bengal': Damodar river.
• 'Sorrow of Bihar': Kosi river.
• Famous waterfall: Jog falls (271 meters).