Drainage class 9 notes, Class 9 geography chapter 3 notes

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9 Class Social Science Geography Chapter 3 Drainage Notes

ClassClass 9
Chapter Chapter 3
Chapter NameDrainage
CategoryClass 9 Geography Notes

Drainage class 9 notes, Class 9 geography chapter 3 notes In which we will get about the drainage pattern, different river basin system, pollution of rivers etc.

Class 9 Social Science Geography Chapter 3 Drainage Notes

πŸ“š Chapter = 3 πŸ“š
πŸ’  Drainage πŸ’ 

❇️ Drainage :-

πŸ”Ή The term Drainage describes the river system of an area.

❇️ Drainage Basin :-

πŸ”Ή The area drained by a single river system is called a Drainage Basin.

❇️ world’s largest drainage basin :-

πŸ”Ή The world’s largest drainage basin is of Amazon River.

❇️ India’s largest drainage basin :-

πŸ”Ή The largest drainage basin in India is from the Ganges River.

❇️ water divide :-

πŸ”Ή Any elevated area, such as a mountain or an upland, separates two drainage basins. Such an upland is known as a water divide.

❇️ Drainage Pattern :-

πŸ”Ά Dendrite :- Dendrite pattern develops where the river channel follows the slope of the terrain. The stream with its tributaries resembles the branches of a tree. 

πŸ”Ά Trellis :- A river joined by its tributaries at approximately right angle develops a trellis pattern. It develops where hard and soft rocks exist parallel to each other. 

πŸ”Ά Rectangular :- A rectangular drainage pattern develops on a strongly rocky terrain. 

πŸ”Ά Radial :- The radial pattern develops when stream flow in different directions from a central peak or dome like structure.

❇️ Perennial river :-

πŸ”Ή The river which is filled with water throughout the year is called Perennial river.

❇️ river system :-

πŸ”Ή A river along its tributaries is called river system.

❇️ Tributary of the large river :-

πŸ”Ή The small river which joins a large river is called the tributary of the large river.

πŸ”Ή eg. Yamuna, Kosi, Gandak etc. are the tributaries of Ganga River.


πŸ”Ή The drainage systems of India are mainly controlled by the broad relief features of the subcontinent. Accordingly, the Indian rivers are divided into two major groups :-

  • The Himalayan rivers
  • The Peninsular rivers

❇️ The Himalayan rivers :-

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

These rivers receive water from rain as well as from melted snow from the lofty mountains. 

The two major Himalayan rivers, the Indus and the Brahmaputra originate from the north of the mountain ranges. 

They have cut through the mountains making gorges. 

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

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

In the middle and the lower courses, these rivers form meanders, oxbow lakes, and many other depositional features in their floodplains. They also have well- developed deltas.

❇️ Major Rivers of Himalayas :-

  • The Indus
  • The Ganga 
  • The Brahmaputra

πŸ”Ή The major Himalayan rivers are the Indus, the Ganga and the Brahmaputra. These rivers are long, and are joined by many large and important tributaries.

❇️ The Indus River System :-

The river Indus rises in Tibet, near Lake Mansarowar. 

Flowing west, it enters India in the Ladakh. 

It forms a picturesque gorge in this part. 

The Indus flows through Baltistan and Gilgit and emerges from the mountains at Attock.

πŸ”Ά its tributaries :- Several tributaries, the Zaskar, the Nubra, the Shyok and the Hunza, join it in the Kashmir region. 

πŸ”Ά Total length of Indus River :- With a total length of 2900 km, the Indus is one of the longest rivers of the world.

  • Beyond this, the Indus flows southwards eventually reaching the Arabian Sea, east of Karachi.

❇️ The Ganga River System :-

πŸ”Ά Total length of Ganga River :- The length of the Ganga is over 2500 km.

πŸ”Ά its tributaries :- The Ganga is joined by many tributaries from the Himalayas, a few of them being major rivers, such as the Yamuna, the Ghaghara, the Gandak and the Kosi.

The headwaters of the Ganga, called the “Bhagirathi’ is fed by the Gangotri Glacier and joined by the Alaknanda at Devaprayag in Uttarakhand. 

At Haridwar, the Ganga emerges from the mountains on to the plains.

The river bifurcates here; the Bhagirathi-Hooghly (a distributary) flows southwards through the deltaic plains to the Bay of Bengal.

The flows southwards into mainstream, Bangladesh and is joined by the Brahmaputra. Further downstream, it is known as the Meghna.

❇️ The Brahmaputra River System :-

The Brahmaputra rises in Tibet east of Mansarowar lake very close to the sources of the Indus and the Satluj. 

It is slightly longer than the Indus, and most of its course lies outside India. 

It flows eastwards parallel to the Himalayas. On reaching the Namcha Barwa (7757 m), it takes a ‘U’ turn and enters India in Arunachal Pradesh through a gorge. Here, it is called the Dihang.

πŸ”Ά its tributaries :- Dibang, the Lohit, and many other tributaries to form the Brahmaputra in Assam.

❇️ Sunderban Delta :-

πŸ”Ή The Sundarban Delta derived its name from the Sundari tree, which grows well in marshland. 

πŸ”Ή It is the world’s largest and fastest growing delta. It is also the home of Royal Bengal tiger.

❇️ The Peninsular rivers :-

A large number of the Peninsular seasonal, as their flow is dependent on rainfall. 

During the dry season, even the large rivers be vers are have reduced flow of water in their channels. 

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

However, some of them originate in the central highlands and flow towards the west. 

Most of the rivers of peninsular India originate in the Western Ghats and flow towards the Bay of Bengal.

❇️ Major rivers of The peninsular :-

  • The Narmada Basin 
  • The Tapi Basin 
  • The Godavari Basin 
  • The Mahanadi Basin 
  • The Krishna Basin 
  • The Kaveri Basin

❇️ The Narmada Basin :-

The Narmada rises in the Amarkantak hills in Madhya Pradesh. 

It flows towards the west in a rift valley formed due to faulting. On its way to the sea, the Narmada creates many picturesque locations. 

The ‘Marble rocks’, near Jabalpur, where the Narmada flows through a deep gorge, and the ‘Dhuadhar falls, where the river plunges over steep rocks, are some of the notable ones.

πŸ”Ά its tributaries :- All tributaries of the Narmada are very short and most of these join the main stream at right angles. 

  • The Narmada basin covers parts of Madhya Pradesh and Gujarat.

❇️ The Tapi Basin :-

The Tapi rises in the Satpura ranges, in the Betul district of Madhya Pradesh. 

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

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

The coastal plains between Western Ghats and the Arabian Sea are very narrow. Hence, the coastal rivers are short. 

The main west flowing rivers are Sabarmati, Mahi, Bharathpuzha and Periyar. 

Find out the states in which these rivers drain the water.

❇️ The Godavari Basin :-

The Godavari is the largest Peninsular river. 

It rises from the slopes of the Western Ghats in the Nasik district of Maharashtra. 

It drains into the Bay of Bengal. Its drainage basin is also the largest among the peninsular rivers. 

The basin covers parts of Maharashtra (about 50 per cent of the basin area lies in Maharashtra), Madhya Pradesh, Odisha and Andhra Pradesh. 

πŸ”Ά Total length of Ganga River :- Its length is about 1500 km. 

πŸ”Ά its tributaries :- The Godavari is joined by a number of tributaries, such as the Purna, the Wardha, the Pranhita, the Manjra, the Wainganga and the Penganga. The last three tributaries are very large. 

  • Because of its length and the area it covers, it is also known as the Dakshin Ganga.

❇️ The Mahanadi Basin :-

  • The Mahanadi rises in the highlands of Chhattisgarh. 
  • It flows through Odisha to reach the Bay of Bengal. 

πŸ”Ά Total length of Ganga River :- The length of the river is about 860 km. 

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

❇️ The Krishna Basin :-

  • Rising from a spring near Mahabaleshwar, the Krishna flows for about 1400 km and reaches the Bay of Bengal. 

πŸ”Ά its tributaries :- The Tungabhadra, the Koyana, the Ghatprabha, the Musi and the Bhima are some of its tributaries. 

  • Its drainage basin is shared by Maharasthra, Karnataka and Andhra Pradesh.

❇️ The Kaveri Basin :-

  • The Kaveri rises in the Brahmagri range of the Western Ghats and it reaches the Bay of Bengal in south of Cuddalore in Tamil Nadu. 

πŸ”Ά Total length of Ganga River :- The total length of the river is about 760 km. 

πŸ”Ά its tributaries :- Its main tributaries are Amravati, Bhavani, Hemavati and Kabini. 

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

❇️ lake :-

πŸ”Ή Where water gets stored in the trough parts of the earth’s surface, it is called lake.

❇️ Lakes in India :-

πŸ”Ή India has many lakes. These differ from each other in size and other characteristics. Most lakes are permanent; some contain water only during the rainy season, like the lakes in the basins of inland drainage of semi-arid regions. 

πŸ”ΉThere are some lakes which are the result of the action of glaciers and ice sheets, while others have been formed by wind, river action and human activities.

❇️ Natural freshwater lakes in India :-

πŸ”Ή The Dal lake, Bhimtal, Nainital, Loktak and Barapani are some other important freshwater lakes.

❇️ Man made lakes in india :-

πŸ”Ή Govind Sagar, Rana Pratap Sagar, Nizam Sagar are important.

❇️ Importance of Lakes :-

  • Provide recreation
  • Develop tourism
  • Maintain the aquatic system
  • Enhance natural beauty of a place
  • Moderate the climate of the surrounding place 
  • Helps in preventing floods during the rainy season
  • Source of hydel power
  • Help maintain flow of water during the summer season
  • Regulate the flow of the river

❇️ Role of Rivers in the Economy :-

Rivers have been of extreme importance throughout human history . Many civilisations developed on the banks of rivers. 

River water is used for domestic and industrial consumption. 

River water is used for irrigation and navigation. 

River water is used for the generation of electricity. 

❇️ River Pollution :-

Domestic , municipal and industrial wastes pollute river waters. 

Untreated sewage wastes and industrial effluents also pollute river water. 

This not only reduces the quality of water but also the self – cleansing mechanism of river water. 

Increasing urbanisation has also polluted river water.

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