CBSE Class 9 Social Science Geography Revision Notes Chapter 3

CBSE Drainage Class 9 notes 

Class 9 Chapter 3 Geography talks about the different aspects of the drainage system of India. The topic might sound very easy, but it can be a challenging topic if you don’t study it well. Hence, students should refer to CBSE Class 9 Geography Chapter 3 Notes to understand the drainage patterns, types of rivers, definitions, the importance of rivers for the country’s economy etc. and prepare for examinations. The CBSE Class 9 notes are prepared by subject matter experts at Extramarks. The experts have ensured that the language is simple for Grade 9 students.

CBSE Class 9 Geography Revision Notes 2023-24

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Class 9 Drainage Notes

Important Drainage Systems of India

The broad relief features dominate the drainage systems in India. The Indian rivers are separated into two significant groups. These are:

• The Himalayan rivers – Such rivers are perennial and have water throughout the year. These rivers are fed by snowy mountains and also receive water from rainfall. Significant examples of such types of rivers are the Ganga and the Brahmaputra. These two rivers originate from the north of the mountain ranges. . In the upper courses, these rivers cause intensive erosional activities and carry huge silt and sand. The river’s forms like meanders, oxbow lakes, deltas and other depositional features mark the middle and the lower course of the rivers.
• The Peninsular rivers – The peninsular rivers are seasonal and solely depend on rainfall. Therefore, these rivers are much shorter and shallower than the Himalayan rivers. Significant examples of such rivers are the Godavari, Krishna, Cauvery, Narmada, Tapti, Narmada, Mahanadi, and Damodar.

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The Himalayan River Systems

The Indus, Ganga and Brahmaputra are three major river systems in India. Let us learn more about it in detail:

• The Indus river system – This river rises near the Mansarovar in Tibet and flows in the west direction to enter India. The tributaries of the Zaskar, the Hunza, and the Nubra join this river in Kashmir. At Mithankot, Beas, Satluj, Chenab and Jhelum join the Indus river. It eventually meets the Arabian Sea in the West.
• The Ganga river system – Ganga rises at the convergence of the Alaknanda and Bhagirathi rivers. Also, it emerges on the plains of Haridwar. The Yamuna is the right-bank tributary of the Ganga, which rises from the Yamunotri glacier. The river gets enlarged because of its tributaries. The mainstream river flows into Bangladesh to join the Brahmaputra and flows into the Bay of Bengal. Also, these rivers form a delta called the Sundarban delta.
• The Brahmaputra river system – The river originates from the Mansarovar lake in Tibet. Most of its course lies outside the country, slightly longer than the Indus. The Brahmaputra river flows parallel to Tsang Po. It turns and enters Arunachal Pradesh at Namcha Barwa. Additionally, the river overflows to flood the banks of Assam.

The Peninsular River Systems

The Western Ghats serve as a water divide in the peninsular region. Some of the rivers are west-flowing, while some are east-flowing. The Godavari, Krishna and Mahanadi flow in the east to drain into the Bay of Bengal. The Narmada and Tapi flow in the West to drain into the Arabian Sea. An account of these rivers is as follows:

• The Narmada basin – The river originates from the Amarkantak hills in Madhya Pradesh. Many beautiful places are associated with the river, like Marble Rocks and Dhauladhar Falls. The basin covers parts of Madhya Pradesh and Gujarat.
• The Tapi basin – The river rises from the Satpura. The river originates from Betul in Madhya Pradesh and flows parallel to the Narmada river. It also flows through Madhya Pradesh, Maharashtra and Gujarat.
• The Godavari basin is also known as Dakshin Ganga and is the largest peninsular river. It originates in Nasik and drains into the Bay of Bengal. It is the largest river basin in South India. The river flows through Madhya Pradesh, Andhra Pradesh, Maharashtra and Odisha. Its tributaries are Manjra, Penganga and Purna.
• The Kaveri basin – The Brahmagiri range gives rise to this river and drains into the Bay of Bengal. Kabini, Amravati, Bhavani and Hemavati are its tributaries. The basin drains Karnataka, Kerala and Tamil Nadu.
• The Krishna basin – This river originates from a spring in Mahabaleshwar. Its tributaries of Musi, Bhima, Koyana and Tungabhadra join the river on its course. The basin drains the states of Karnataka, Andhra Pradesh and Maharashtra.

Lakes in India

The Geography class 9 chapter 3 notes, in NCERT books tells you about the lakes of India, which can be classified into the following depending on their size and other features. These are:

• Permanent lakes – these lakes have water all around the year.
• Non-Permanent lakes – these lakes usually drain in the semi-arid region.
• Glacial lakes – such lakes originate from glaciers and ice sheets.
• Oxbow lakes – these rise from the meandering regions.
• Lagoons – such lakes are formed from the spits and bars. Kolleru lake and lake Chillika are famous lagoons.
• Saltwater lakes – some have saline waters and are known as saltwater lakes. Such lakes drain the dry regions and are used to produce salt.
• Freshwater lakes originate from melting glaciers and ice sheets in the Himalayan belt. The largest freshwater lakes are found in Jammu and Kashmir.
• Man-made lakes – such lakes are artificially created by humans. There are only a few man-made lakes. One such example is the Guru Govind Sagar.

Rivers and Their Role in the Economy

Rivers play a significant role in the economy of a country. Therefore, they are indispensable, and importance  in many ways:

• Rivers are used for navigation.
• It attracts human settlements on the banks for human survival.
• It also helps in hydroelectric power generation.
• The river aids in the irrigation process. It supports the Indian agriculture system for the sustenance of livelihood.

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Pollution and River

River water has been massively used for agriculture, domestic and municipal purposes for ages. Untreated pollutants like sewage and industrial wastes are discharged into the river. Thus, these pollute the river and decrease the self-cleaning capacity of water resources. Increasing industrialisation and urbanisation increase the level of pollution in the river.