Class IX Geography�Topic: Drainage

Learning Objectives

• Drainage Meaning | Drainage Basin | Water Divide

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• Drainage Pattern

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• Drainage System in India

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• Role of Rivers in Economy

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• River Pollution

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Drainage | Drainage Basin | Water Divide

• Term drainage describes River system of an Area
• Area drained by River along with its Tributaries & distributaries is know as Drainage Basin
• An Elevated Area such as Mountain or an upland, separate two drainage basins such upland is know as Water Divide

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Do You Know?

1. Which is the World’s Largest Drainage Basin?
2. Which River has largest River Basin in India?

Drainage Pattern

There are 4 types of drainage patterns:

Dendritic, Trellis, Rectangular, and Radial patterns

• A Dendritic drainage pattern is the most common form and looks like the branching pattern of tree roots.
• A Trellis drainage pattern is the short subsequent streams meet the main stream at right angles. Through soft rocks differential erosion paves the way for tributaries.
• A Rectangular drainage pattern is the main stream bends at right angles and the tributaries join at right angles creating rectangular patterns
• The Radial drainage pattern develops around a central elevated point and is common to conically shaped features

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Drainage System in India

• Indian drainage system consists of a large number of small and big rivers
• These are mainly controlled by Broad Relief Features of Subcontinent

Difference between �Himalayan Rivers & Peninsular Rivers

These are different from Each other in many ways part from its originate.

The Himalayan Rivers

• The major Himalayan rivers are the Indus river, Ganga river, and the Brahmaputra. These are long & joined by many large and important tributaries
• River System: River along with its tributaries is called as River system

1) The Indus River System

• Indus is one of the longest rivers in the world with a total length of 2900 km
• The river Indus rises in Tibet, near Lake Mansarowar
• It enters India in the Ladakh district of Jammu and Kashmir where it forms a picturesque gorge
• The Satluj, the Beas, the Ravi, the Chenab and the Jhelum join together to enter the Indus near Mithankot in Pakistan

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What is Indus Water Treaty 1960?

2) The Ganga River System

• The source of the Ganga called the ‘Bhagirathi’ is fed by the Gangotri Glacier and joined by the Alaknanda at Devaprayag in Uttarakhand
• The Ganga emerges from the mountains to the plains at Haridwar
• 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 length of the Ganga is over 2500 km
• Farakka in West Bengal is the northernmost point of the Ganga delta where the Ganga river divides into 2 parts
• The Bhagirathi-Hooghly flows southwards through the deltaic plains to the Bay of Bengal
• The mainstream flows southwards into Bangladesh and is joined by the Brahmaputra. Further downstream, it is known as the Meghna. The Meghna River flows into the Bay of Bengal and form Sundarban Delta

How Sundarban Delta was Named?

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3) The Brahmaputra River System

• The Brahmaputra rises in Tibet east of Mansarowar lake.
• It is slightly longer than the Indus
• On reaching the Namcha Barwa (7757 m), it takes a ‘U’ turn and enters India in Arunachal Pradesh where it is called the Dihang
• Dihang is joined by the Dibang, the Lohit, and many other tributaries to form the Brahmaputra in Assam

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By which name Brahmaputra is known in Tibet & Bangladesh?

The Peninsular Rivers

• The main water divide in Peninsular India is formed by the Western Ghats
• Most of the major rivers of the Peninsula, such as the Mahanadi, the Godavari, the Krishna and the Kaveri flow eastwards and drain into the Bay of Bengal
• These rivers make deltas at their mouths
• The Narmada and the Tapi are the only long rivers, which flow west and make estuaries

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1) The Narmada Basin

• The Narmada rises in the Amarkantak hills in Madhya Pradesh
• The Narmada flows through a deep gorge at the ‘Marble rocks’ near Jabalpur
• At Dhuadhar falls the river jumps over steep rocks
• The Narmada basin covers parts of Madhya Pradesh and Gujarat

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What is Namami devi Narmade?

2) The Tapi Basin

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

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

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3) The Godavari Basin

• The Godavari is the largest Peninsular river. Its length is about 1500 km
• It rises from the slopes of the Western Ghats in the Nasik district of Maharashtra
• The basin covers parts of Maharashtra, Madhya Pradesh, Odisha and Andhra Pradesh
• The Godavari is joined by a number of tributaries
• Owing to its length and the area it covers, it is also known as the Dakshin Ganga

4) The Mahanadi Basin

• The Mahanadi rises in the highlands of Chhattisgarh

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• The length of the river is about 860 km

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

5) The Krishna Basin

• It rises from a spring near Mahabaleshwar

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• The length of the river is about 1400 km

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

6) The Kaveri Basin

• The Kaveri rises in the Brahmagri range of the Western Ghats

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• The total length of the river is about 760 km

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

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• This makes the second Biggest waterfall in India

Do You Know?

• How much percent World’s surface is covered with water?

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• How much percent fresh water is available on Earth?

Lakes

India has many lakes. These lakes differ from each other in size and other characteristics.

• Most lakes are permanent
• Some contain water only during the rainy season
• Some lakes are the result of the action of glaciers and ice sheets
• Some have been formed by wind, river action and human activities

Different lakes are:

• A meandering river across a floodplain forms cut-offs that later develops into ox-bow lakes
• Spits and bars form lagoons in the coastal areas. Eg: the Chilika lake
• Lakes in the region of inland drainage are sometimes seasonal. For example, the Sambhar Lake in Rajasthan is a salt water lake which is used for producing salt
• Most of the freshwater lakes are in the Himalayan region

Importance of Lakes

Lakes are useful to human beings in many ways:

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• Lakes help to regulate the flow of a river
• During heavy rains, these lakes prevent flooding.
• During the dry season, these lakes help to maintain an even flow of water
• Lakes can also be used for developing hydel power
• Lakes moderate the surrounding climate, maintain the aquatic ecosystem, enhance natural beauty, and provide recreation

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Name some Natural & Artificial Lakes in India?

Role of Rivers in the Economy

• Rivers have been of fundamental importance throughout human history

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• Water from rivers is a basic natural resource, essential for various human activities

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• Rivers are used for irrigation, navigation, hydropower generation etc.

River Pollution

• The growing domestic, municipal, industrial and agricultural demand for water from rivers is affecting the quality of water
• Rivers are getting polluted as a heavy load of untreated sewage and industrial effluents are getting emptied into the rivers
• Concern over rising river pollution led to the launching of various action plans to clean the rivers

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National River conservation Plan:

• River Cleaning Program
• Ganga Action Plan was expanded to covers under NRCP in 1995 to improve water quality

Thank You