Q and Ans: Drainage

Chapter 3 Drainage 

Q. Define a river system and describe characteristics of river Indus.

Answer: A  river along with its tributaries is called a river system.

Characteristics of River Indus:

1 River Indus rises in Tibet near Mansarovar lake.

2 Its total length is 2,900 km and is one of the longest rivers of the world.

3 It flows through Baltistan and Gilgit and emerges from the mountain at Attock.

4 Majority flows through Pakistan and help in agricultural activities.

5 The main tributaries of Indus are Nubra, Hunza, Sulley, Beas, Ravi, Chenab, Jhelum. 

6. The Indus river flows southwards eventually reaching the Arabian Sea, east of Karachi.

Q. Describe the main features of river Brahmaputra.

Answer: features are

1 The Brahmaputra originates in Tibet where it is known as Tsangpo.

2 It flows eastwards parallel to the Himalayas, but it takes a U-turn around the Namcha Barwa and enters India in Arunachal Pradesh.

3 It is responsible for creating a havoc of floods in Assam and Bangladesh.

4 This river receives less volume of water and has less silt in Tibetan part, but it carries a large volume of water and silt in India.

5 It has a braided channel in most of its length in Assam with a few large islands within the channel.

Q Why are Peninsular rivers seasonal in nature?

Answer:

1 The flow of Peninsular rivers is dependent on rainfall.

2 The Peninsular rivers have shorter and shallower courses as compared to their Himalayan counterparts.

3 The tributaries are very short and less in number and bring quite less amount of water which hardly increases the amount of water of the main river.

 

Q Which two peninsular rivers flow westward? Mention  similarities between these two rivers.

Answer:

Narmada and Tapi.

Similarity:

These rivers flow through rift valley. .

The tributaries of these rivers are small in size.

Q Describe the main features of Narmada Basin.

Answer:

1 All the tributaries of the Narmada are very short and most of these join the mainstreams at right angle.

2 The river forms an estuary before entering into the Gulf of Khambhat.

3 The river Narmada rises in the Amarkantak hills and flows towards the west in a rift valley formed due to faulting.

Q Describe the main features of Tapi Basin.

Answer:

1 It is the second largest river of the peninsular, rises in the Satpura ranges, in the Betul district of Madhya Pradesh.

2 It also flows in a rift valley parallel to the Narmada but it is much shorter in length.

3 Its basin covers parts of Madhya Pradesh, Gujarat and Maharashtra.

Q Describe any three important features of the Krishna Basin.

Answer:

1 The river Krishna rises from a spring near Mahabaleshwar. It flows for about 1400 kms.

2The Tungabhadra, the Koyana, the Ghatprabha, the Musi and the Bhima are some of its tributaries.

3 Its drainage basin is shared by Maharashtra, Karnataka and Andhra Pradesh.

Q Write the features of Godavari River .

Answer:

1 The Godavari is the largest peninsular river.

2 Its drainage basin is also the largest among the peninsular rivers. 

3 The basin covers parts of Maharashtra, Madhya Pradesh, Odisha and Andhra Pradesh.

4 The Godavari is joined by a number of tributaries such as the Purna, the Wardha, the Pranhita, the Manjra, the Wainganga and the Penganga.

5 Because of its length and the area it covers, it is also known as the ‘Dakshin Ganga’

Q Describe important features of the Mahanadi Basin.

Answer:

1 The Mahanadi rises in the highlands of Chhattisgarh.

2 It flows through Odisha to reach the Bay of Bengal. 

3 The length of the river is about 860 kms.

4 Its drainage basin is shared by Maharashtra, Chhattisgarh, Jharkhand and Odisha.

Q Describe important features of the Kaveri Basin.

Answer:

1 The Kaveri rises in the Brahmagri range of the Western Ghats and it drains in the Bay of Bengal

2 Its main tributaries are Amravati, Bhavani, Hemavati and Kabini.

3 Its basin drains parts of Karnataka, Kerala and Tamil Nadu.

Q “Rivers constitute the most useful natural resources.” Support the statement with five suitable examples.

Answer:

Rivers are the most important natural resources because

1 Rivers provide water for survival and growth of all organisms.

2 Rivers provided ideal conditions for the early man to lead a settled life.

3 Rivers have built flood plains, deltas and provide fertile soil for agriculture.

4 Water from rivers is used for drinking, irrigation and for generating hydro- electricity.

5 Man is able to supplement his food supply with the fish in the rivers. 

6 Rivers also serve as natural waterways.

7 World’s earliest civilization developed in the river valleys, e.g. Indus Valley civilization etc. 

8 River Valleys are the world’s best agricultural lands, and are densely populated regions.

Q Explain the main features of the rivers originating from the Himalayas.

Answer:

1 Most of the Himalayan rivers are perennial. It means that they have water throughout the year.

2 The Himalayan rivers have long courses from their source to the sea.

3 These perform intensive erosional activity in their upper courses and carry huge loads of silt and sand.

4 They have cut through the mountains making gorges.

5 They also form well-developed deltas.

Q Write the main features of the Ganga river system.

Answer:

1 The Ganga has two headstreams-the Alaknanda and the Bhagirathi. They join together at Devprayag.

2 From the Himalayas the Ganga enters the plains at Haridwar.

 3 It is joined together by a large number of tributaries like Ghaghara, the Gandak and the Kosi.

4 The Yamuna and the Son are the two main right bank tributaries of the Ganga.

5 The Ganga enters Bangladesh as Padma.

6 The length of the Ganga is over 2500 km, and it has the largest basin.

Q Mention the main features of the Ganga Action Plan.

Answer:

Main Features of the Ganga Action Plan:

1 Sewage flowing into the river is to be diverted to other locations for treatment and conversion into energy source.

2 Steps have been taken to supply safe drinking water by constructing electric crematoriums and separating bathing Ghats.

3 The diversion of several major drains carrying wastes into the river has been completed in cities like Varanasi, Patna and Kanpur and pollution level has been decreased.

4 Infrastructure capable of diverting and treatment 835 million litres per day of domestic waste or sewage has been created.

5 Ganga Action Plan has been merged with National River Conservation Plan. 

6 It now covers 152 towns located along 27 Inter-state rivers in over 16 states.

Q Distinguish between perennial and non-perennial rivers.

Answer:

 Perennial    

(i) These rivers have water throughout the year.    

(ii) Rainfall and melted snow are the source of water for these rivers.    

(iii) Most of the Himalayan rivers are perennial.   

 

Non-Perennial

1These have water only during the rainy season.

2 Rainfall is the only source of water for these rivers.

3 Most of the Peninsular rivers are non-perennial.

Q What are the major factors responsible for river pollution? Explain.

Answer:

High Demand of Water: The growing domestic, municipal, industrial and agricultural demand for water from rivers naturally affects the quality of water. As a result, more and more water is being drained out of the river reducing its volume.

Industrialisation: A heavy load of untreated sewage and industrial effluents are emptied into the rivers. This affects not only the quality of water but also the self-cleansing capacity of the river. For example, given the adequate streamflow, the Ganga water is able to dilute and assimilate pollution loads within 20 km of large cities. But the increasing urbanisation, and industrialisation do not allow it to happen and the pollution level of many rivers has been rising.

Agricultural Pollution: The extensive uses of chemicals in the form of fertilizers and pesticides in agriculture have left the water bodies contaminated with heavy metals. Such heavy metals enter human body through the food we eat, and many of them cause health problems such as cancer.