9 Class Social Science Geography Chapter 3 Drainage Notes
|Category||Class 9 Geography Notes|
Class 9 Social Science Geography Chapter 3 Drainage 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
📚 Chapter = 3 📚
💠 Drainage 💠
❇️ Drainage :-
🔹 The term Drainage describes the river system of an area.
❇️ Drainage Basin :-
🔹 The area drained by a single river system is called a Drainage Basin.
❇️ world’s largest drainage basin :-
🔹 The world’s largest drainage basin is of Amazon River.
❇️ India’s largest drainage basin :-
🔹 The largest drainage basin in India is from the Ganges River.
❇️ water divide :-
🔹 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 :-
🔶 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.
🔶 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.
🔶 Rectangular :- A rectangular drainage pattern develops on a strongly rocky terrain.
🔶 Radial :- The radial pattern develops when stream flow in different directions from a central peak or dome like structure.
❇️ Perennial river :-
🔹 The river which is filled with water throughout the year is called Perennial river.
❇️ river system :-
🔹 A river along its tributaries is called river system.
❇️ Tributary of the large river :-
🔹 The small river which joins a large river is called the tributary of the large river.
🔹 eg. Yamuna, Kosi, Gandak etc. are the tributaries of Ganga River.
❇️ DRAINAGE SYSTEMS IN INDIA :-
🔹 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
🔹 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.
🔶 its tributaries :- Several tributaries, the Zaskar, the Nubra, the Shyok and the Hunza, join it in the Kashmir region.
🔶 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 :-
🔶 Total length of Ganga River :- The length of the Ganga is over 2500 km.
🔶 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.
🔶 its tributaries :- Dibang, the Lohit, and many other tributaries to form the Brahmaputra in Assam.
❇️ Sunderban Delta :-
🔹 The Sundarban Delta derived its name from the Sundari tree, which grows well in marshland.
🔹 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.
🔶 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.
🔶 Total length of Ganga River :- Its length is about 1500 km.
🔶 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.
🔶 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.
🔶 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.
🔶 Total length of Ganga River :- The total length of the river is about 760 km.
🔶 its tributaries :- Its main tributaries are Amravati, Bhavani, Hemavati and Kabini.
- Its basin drains parts of Karnataka, Kerala and Tamil Nadu.
❇️ lake :-
🔹 Where water gets stored in the trough parts of the earth’s surface, it is called lake.
❇️ Lakes in India :-
🔹 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.
🔹There 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 :-
🔹 The Dal lake, Bhimtal, Nainital, Loktak and Barapani are some other important freshwater lakes.
❇️ Man made lakes in india :-
🔹 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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