GSEB Solutions Class 9 Social Science Chapter 15 Drainage System

Gujarat Board GSEB Textbook Solutions Class 9 Social Science Chapter 15 Drainage System Textbook Questions and Answers, Additional Important Questions, Notes Pdf.

Drainage System Class 9 GSEB Solutions Social Science Chapter 15

Gujarat Board Class 9 Social Science Drainage System Textbook Questions and Answers

1. Write short answer for the following questions.

Question 1.
Give difference: Himalayan rivers and Peninsular rivers.
Answer:
Himalayan Rivers

1. These rivers contain water throughout the year.
2. They are long, deep and having slow flow.
3. They are used as waterways.
4. Their river basin areas are large.
5. Meanders are seen.

Go through these Social Science Chapter 15 Drainage System GSEB Class 9 Notes to score well in your exam.

Peninsular Rivers

1. These rivers are seasonal.
2. They are short, shallow and having fast flow.
3. They cannot be used as waterways.
4. Their river basin areas are comparatively.
5. Meanders are not seen.

Question 2.
Explain Drainage Pattern and Water Divide.
Answer:

1. The word drainage system is used for the systematic pattern of rivers.
2. It is seen that one main river along with its tributaries come from different directions and meet into a single river.
3. The water of these rivers is emptied into a water reservoir, sea or a desert. Thus, when a flow of a river flows through its system in any area it is called a river basin.
4. When a mountain or an upland separates the flow of water from one another, it is called water divide.

Question 3.
Explain the utility of lakes.
Answer:
Utility of Lakes

1. They are used for navigation and hydropower generation.
2. They help to regulate the flow of a river.
3. They also moderate the climate of surroundings.
4. They maintain the aquatic system.
5. They help develop tourism.
6. They enhance natural beauty and provide recreation.

Question 4.
State the remedies to prevent water pollution.
Answer:

1. Water purification projects must be implemented through National River Conservation Project.
2. Industrial units should filter harmful contents from the chemical effluents released by them in rivers.
3. Every citizen should take care not to mix up the domestic waste into rivers.
4. Strict rules should be formed to prevent industrial units from releasing industrial effluents in rivers.

Question 5.
‘Godavari is named as Ganga of South’. Give reasons.
Answer:

1. It has the largest basin among the peninsular rivers.
2. It starts from the slopes of Western Ghats near Nasik in Maharashtra.
3. It flows to the east and meets Bay of Bengal.
4. About 50% of its basin lies in Maharashtra and the rest is in Madhya Pradesh and Andhra Pradesh.
5. The length of Godavari is about 1465 km. Many tributaries meet Godavari. Among them Puma, Vardha, Pranhita, Manjara, Vainganga and Penganga are included.
6. Godavari has a longer flow and large basin. So, it is called as ‘Ganga of South’.

2. Answer the following.

Question 1.
Explain the Ganga River System.
Answer:

1. River Bhagirathi and Alaknanda emerging from the Gangotri area in Himalayas, merge with each other near Devprayag (Uttarakhand). Hence, Ganga river leave the mountains terrain and enters plains near Haridwar.
2. Many Himalayan rivers like Ghaghra, Gandak and Kosi meet Ganga.
3. Yamuna emerges from Yamnotri in Himalayas flowing to the right side of Ganga, it merges with Ganga near Allahabad.
4. The origin of Ghaghra, Gandak and Kosi rivers lies in Nepal. Hence, the northern plain experiences flood disasters every year.
5. India has been able to attain prosperity in agriculture through fertile plains formed by these rivers.
6. Chambal and Betwa originate in peninsular plateau and meet Yamuna. Son river meets Ganga.
7. The combined flow of rivers from north and south is divided ahead into two branches.
8. One branch enters Bangladesh and is known there as Padma while another branch is known as Bhagirathi-Hugli in West Bengal. Finally these two branches meet the Bay of Bengal.
9. The flow of Ganga which is known as Padma in Bangladesh merges there with Brahmaputra river and their combined flow is known as ‘Meghna’.
10. The Ganga-Brahmaputra delta is the most fertile delta. It is known as ‘Sunderban’.

Question 2.
Discuss the Narmada Basin.
Answer:

1. Narmada originates near Amarkantak plateau in Madhya Pradesh flow Westwards in rift valley.
2. Narmada Basin is spread in Madhya Pradesh and Gujarat.
3. The length of Narmada is 1312 km.
4. The length of its tributaries is not very long. So, most of the river meet at right angles.
5. River Narmada flows through a rocky terrain of marbles. It flow’s faster due to slope. The Dhuadhar falls are located here.

Question 3.
Describe in detail Krishna and Kaveri basin.
Answer:
Krishna Basin:

1. It starts from Mahabaleshwar in Maharashtra.
2. Its tributaries are Tungabhadra, Koyna, Ghatprabha, Musi and Bhima.
3. Its basin extends in Maharashtra, Karnataka and Andhra Pradesh.
4. Its tributaries length is about 1400 km.

Kaveri Basin:

1. It has its origin in the Brahmagiri Range in Western Ghats.
2. Amravati, Bhavani, Hemvati and Kalini are its main tributaries.
3. It is spread over a Kerala, Karnataka and Tamil Nadu.
4. River Kaveri meets the Bay of Bengal to the South of Cuddalore in Tamil Nadu.

4. Find out the correct option from the given options:

Question 1.
Which lakes are formed due to meandering of rivers?
A. Lagoon
B. Ox-bow
C. Oval-shape
D. Square
Answer:
B. Ox-bow

Question 2.
What is it called when a mountain or an upland separates the water flow of rivers from one another?
A. Water formation
B. Water divide
C. River system
D. Basin
Answer:
B. Water divide

Question 3.
Which of the following is not a peninsular river?
A. Godavari
B. Krishna
C. Kosi
D. Kaveri
Answer:
C. Kosi

Question 4.
Which of the following lakes is used for producing salt?
A. Dhebar
B. Sambhar
C. Wuler
D. Nal
Answer:
B. Sambhar

Question 5.
Which are the main tributaries of Ganga?
A. Yamuna, Ghaghra, Gandak and Kosi
B. Yamuna, Chambal, Ghaghra and Kosi
C. Yamuna, Ghaghra, Sharavati and Kosi
D. Narmada, Ghaghra, Gandak and Kosi
Answer:
A. Yamuna, Ghaghra, Gandak and Kosi

Gujarat Board Class 9 Social Science Drainage System Additional Important Questions and Answers

I. Answer the following questions.

Question 1.
What do you mean by drainage system and drainage pattern? Name the types of drainage pattern found in Indian rivers.
Answer:
The study of river pattern of a region is known as the drainage system. The natural arrangement of a river and her tributaries is called the drainage pattern. The drainage pattern of Indian rivers can be divided into four parts:

1. Dendritic drainage pattern
2. Trellis drainage pattern
3. Rectangular drainage pattern
4. Centrifugal/Radial pattern.

Question 2.
Describe different drainage paterns.
Answer:
The drainage pattern of Indian rivers can be divided into four parts:
(A) Dendritic Pattern:
When the arrangement of a river and its tributaries make a shape of the branches of a tree, it is called dendritic pattern, For example-Ganga.

(B) Trellis Pattern:

• When streams starting from mountainous region meet one another due to the slopes they make a net-like shape. This pattern of river is called trellis pattern of river.
• For example, many streams of Himalayan Mountains meet Himalayan rivers and form a trellis pattern.

(C) Rectangular Pattern:

1. When the main river and its tributaries meet each other at right angles, they form a rectangular pattern.
2. Mostly, rivers flowing through rift valleys form such river rectangular river system. For example, Narmada.

(D) Radial (Centrifugal) Pattern:

1. In this drainage pattern, the rivers flow outwards from one central hilly region.
2. Radial pattern is found in the river of Saurashtra.

Question 3.
Explain the flow of a river in various sections (courses).
Answer:
The flow of river can be divided in three sections. Each section is called a ‘Course’. There are three courses of river. They are:

1. Upper Course
2. Middle Course
3. Lower Course.

(1) Upper Course:

1. When a river starts from mountainous region, it flows quickly with lots of energy. This causes intense erosion.
2. The upper course carries huge volume of sand and sediments along with it.

(2) Middle Course:
In the middle course, the river flow slowly, but spreads on wide areas. This course transports lots of sediment and hence the river looks muddy.
(a) Formation of meanders: The fall of river found in upper course changes to sideways motion. The river starts moving, to the right side then the left side, causing bends or loops in the shape of horseshoe (i.e., animal hoof) in the river. These bends are called meanders.
(b) Formation of lakes: At times due to the meanders and the impact of floods, the loop formed during meanders gets cut-off from the main channel. The cut-off loop is called an ox bow lake.

(3) Lower Course:

1. The end of the river is called the mouth. Lower course refers to the end of the journey of the river.
2. In the lower course, the river has a high volume of water and a large discharge of sediments but at low energy level.
3. The river channel is now deep and wide and the landscape around it is flat.

(a) Formation of delta: At the mouth of a river, there is often a river delta a river delta is a large, muddy area where the river splits into many different slow-flowing channels i.e., tributaries. Delta is a highly fertile triangular-shaped plain.

Question 4.
What is river system? Name the major river systems of Himalayan rivers?
Answer:
The large network of streams, lakes and rivers that are part of a larger river’s network of tributaries and distributaries is together called the river system. There are three main river system in the Himalayan river system. They are:

1. Sindhu River System
2. Brahmaputra River System
3. Brahmaputra River System.

Question 5.
Write a short note on Sindhu (Indus) River System.
Answer:
Sindhu (Indus) River System:

1. It is one of the longest rivers of the world, with the length of 2900 km.
2. Sindhu river originates from near Mansarovar region in Tibet.
3. It has formed many inaccessible deep ravines and passes.
4. About one-third of its basin falls in the mountainous region of Jammu and Kashmir.
5. First, Sindhu flows to north and then turns westwards and enters India via. Ladakh in Jammu and Kashmir.
6. Here, Zaskar, Nubara, Shyok and Hunza rivers meet Sindhu.
7. From Jammu and Kashmir, Sindhu rivers starts flowing towards Pakistan.
8. In Punjab of Pakistan, main tributaries namely Jhelum, Chenab, Ravi, Beas and Satluj meet Sindhu at a place called Mithankot.
9. Then the combined flow of all these rivers ultimately flow southwards and meets Arabian Sea.
10. These rivers flow at a slower speed in the plain.
11. In 1960, a Treaty was signed with Pakistan regarding the distribution of Sindhu river water.
12. According to this, India can use only 20% of its water.
13. Waters of Satluj, Ravi and Beas rivers are used for irrigation in the states of Punjab, Haryana and south-western part of Rajasthan.

Question 6.
What is delta region of Ganga called? Why did it get this name?
Answer:

• A large number of ‘Sundari’ trees grow in the delta region of Ganga. Hence, this region is called Sundarban delta.
• It is quite famous for mangrove forests.

Question 7.
Why are there many meanders on Ganga River System between Ambala and Sunderban delta?
Answer:

1. Ambala city works as a water-divide between Ganga and Sindhu rivers.
2. Ambala to Sunderban is about 1800 km, but it has a very gentle slope.
3. Ambala is at an altitude of 300 meters from sea level whereas Sunderban is at sea-level.
4. Considering this, the slope happens to be 6 km per one metre (1800/300 = 6).
5. Due to this gentle and continuous slope there are many meanders on this river.

Question 8.
State the positive and negative aspects of Ganga River System.
Answer:

1. Several rivers meet Ganga and form the Ganga River system.
2. All these rivers contain a very large volume of water. Hence, the northern plain experiences flood almost every year.
3. These floods cause a heavy loss of lives and property in some areas.
4. On the other hand, the plain formed by these rivers are extremely fertile.
5. Due to these rivers India has been able to prosper tremendously in agriculture.

Question 9.
Give a detailed idea about Brahmaputra River System.
Answer:
Brahmaputra River System:

1. Brahmaputra is the only river having a masculine name.
2. Brahmaputra which is about 2900 km long is longer than Sindhu but most of its flow is outside India.
3. It originates in Tibet near the origin of Sindhu and Satluj rivers.
4. It is called Tsang Po in Tibet.
5. In Tibet, it flows parallel to Himalayas in the eastern direction.
6. It then takes a ‘U’ turn at the mountain peak called Namcha Barwa and enters India through Arunachal Pradesh. Here, it is known as Dihang.
7. This river, with Dihang, Lohit and Kenula tributaries collectively is known as Brahmaputra in Assam.
8. Brahmaputra is known as Jamuna in Bangladesh.
9. ‘Mazuli’, an island in Brahmaputra, is the largest riverine island in the world.
10. The Tibet part of Brahmaputra contains less sediment.
11. In India, Brahmaputra flows through areas receiving very heavy rainfall and hence, the river carries much alluvium.
12. Many tributaries meet this river in Assam.
13. During monsoon, the total volume of Brahmaputra river water and her tributaries rises greatly causing floods in Assam and Bangladesh.
14. Due to increased sand level of this river at several places its surface gets higher. As a result, there are frequent changes in the course of river.

Question 10.
Brahmaputra gets flooded heavily during monsoon. Give reason.
Answer:

1. Brahmaputra originates in Himalayas and hence contains much water.
2. This river flows through Arunachal Pradesh and Assam in India where many small rivers merge with her.
3. Moreover these rivers flow through areas that experience heavy rainfall.
4. Hence, Brahmaputra river water rises greatly and so it gets flooded heavily during monsoon.

Question 11.
Name the major Peninsular rivers flowing eastwards and westwards.
Answer:

1. Western Ghats is considered to be the main water divide for peninsular rivers.
2. Major rivers such as Mahanadi, Godavari, Krishna, Kaveri, etc. flow eastwards and meet the Bay of Bengal.
3. Other smaller rivers which flow eastwards and meet Bay of Bengal include Damodar, Brahmani, Vaitami and Suvamarekha.
4. Major rivers like Narmada,’Tapi, Sabarmati and Mahi (Mahisagar) flow from east to west and meet Arabian Sea in the west.

Question 12.
Write a brief note on Tapi Basin.
Answer:

1. River Tapi is almost 724 km long.
2. It originates from Satpura ranges in Betul district of Madhya Pradesh.
3. It flows in a rift valley, parallel to Narmada, and meets Arabian Sea.
4. Basin to Tapi lies in Madhya Pradesh and Gujarat.

Question 13.
Write a brief note on Mahanadi Basin.
Answer:

1. Mahanadi originates in the mountainous areas of Chhattisgarh.
2. It is about 860 km long.
3. It flows through Odisha and meets Bay of Bengal.
4. Its basin is spread in Chhattisgarh, Jharkhand and Odisha.

Question 14.
How are lakes formed?
Answer:
Lakes are formed through several ways:

1. Lakes are formed due to melting of snow.
2. Some lakes are also formed when water gets filled in depressions.
3. Some are formed due to tectonic movements.
4. A few lakes are formed due to wind, rivers and human actions.
5. Oxbow lakes are formed in rivers that have many meanders.
6. There are also many man-made (artificial) lakes in India created due to dams of the rivers.
7. Sea tides create ‘lagoon’ lakes.

Question 15.
Write a short note on importance of rivers.
Answer:
Importance of Rivers:

1. Rivers have been our part of life since the birth of humanity.
2. They are an extremely important natural resource of water. They are also very for innumerable human activities.
3. Rivers satisfy various needs of man.
4. Ancient civilization used to settle and even flourish along rivers.
5. Many important cities have developed along the river banks. Delhi, Kolkata, Ahmedabad, Bharuch, Surat are a few of them.
6. They fulfil considered to be a base of development for an agrarian country like India. They plays a very important role in development of agriculture and industries.
7. River water is also used for drinking, generating hydel power and for navigation.

Question 16.
How does a river get polluted? Explain.
Answer:
River pollution:

1. River water is widely used in domestic activities, agriculture and in industrial production.
2. People worship rivers and call them ‘Lokmata’.
3. Inspite of these facts, we release industrial pollutants in the rivers.
4. The sewage water is dumped into the rivers.
5. We also throw solid waste as well as idols, flowers, coconuts, etc. on the name of religion in rivers. All these human acts pollute the rivers.
6. Pollution of river water has become our national problem.
7. Government is trying to prevent river pollution.
8. Public need to support government’s initiative and prevent pollution of rivers.

Question 17.
Rivers are called ‘Lokmata’. Why?
Or
Why are rivers considered lifelines of human civilisation.
Answer:

1. River are an inseparable part of a country.
2. They carry various minerals dissolved with them and hence turn the landmass fertile.
3. River mouth, where freshwater of the river merges with the saline oceanic water, is the largest bioproductive area.
4. Many major cities are developed across rivers.
5. People are dependent on rivers for various activities like cattle rearing, agriculture, etc.
6. Rivers also serve as an important medium for transport, tourist attraction, trade and commerce.
7. Dams are constructed across rivers which help in irrigation and hydroelectricity production.
8. Due to all these important benefits, rivers are considered to be the lifeline of human civilization and are called ‘Lokmata’.

II. Map-based question.
On an outline map of India, mark the major.

Answer: