This chapter is about drainage which describes the river system of an area with its tributaries, river flow, and distinct characteristics. Small streams which flow from different directions and form a larger water body which drains into a lake, a sea or an ocean. An area drained by a single river system is called a drainage basin. Often we find hills, mountains or upland features separating two drainage basins, and this elevated feature is called the water divide.
This Chapter has been effectively covered by Extramarks using pictures, maps, comprehensive answers etc., in an easy to understand language. The subject matter experts have ensured a concise syllabus per NCERT directions, keeping the CBSE examination in mind, supplemented by the Class 9 Geography Chapter 3 question answer.
The subject of Social Sciences is vital in every walk of life, and students can perform well in future competitive examinations like UPSC only if their fundamental understanding is strong enough.
Key Topics Covered in NCERT Solutions for Class 9 Geography Chapter 3
The NCERT Solutions for Class 9 Geography Chapter 3 covers the following topics:
Introduction
The drainage in India originates from two main physical features, viz the Himalayas and the peninsula. These river systems have unique characteristics and flow patterns, as explained in the NCERT Solutions for Class 9 Geography Chapter 3.
The Indian rivers are divided into two major groups: The Himalayan rivers and the Peninsular rivers.The rivers emanating from the Himalayas receive water from both the rainfall and the melting ice, due to which they never dry up. They are also known as Perennial rivers. The Indus and the Brahmaputra are two such perennial rivers. These rivers are very swift and often cut through the mountain rocks forming gorges. They cause deep erosion and carry significant silt and sand toward the sea. The Himalayan rivers leave behind many depositional features like meanders and oxbow lakes in the middle courses and deltas in the lower courses.
The Peninsular rivers, on the other hand, their flow solely depend on rainfall and they are seasonal. . Large rivers lose their flow during the dry season. The Peninsular rivers are slow-moving, shallower, and shorter courses than their Himalayan counterparts. Most of the peninsular rivers originate in the Western Ghats and flow towards the Bay of Bengal in the east.
The Himalayan Rivers
A river along with its tributaries is called a river system. In this Chapter, we learn about India’s three long river systems, viz the Indus, the Ganga, and the Brahmaputra.
The river Indus originates in Tibet, near lake Mansarovar, and enters India via Ladakh. Many tributaries like the Zanskar, the Nubra, the Shyok, and the Hunza join the Kashmir region. The Indus river system leaves some impressive gorges and valleys in its wake, attracting tourists from far and wide. It flows further towards Pakistan, via east Karachi, to eventually join the Arabian Sea. The Indus is 2,900 km long, and it’s one of the longest rivers of the world. A third of the Indian basin is located in India (Ladakh, Jammu and Kashmir, Punjab and Himachal Pradesh) and two thirds in Pakistan.
The Ganga riverine is a little shorter at 2,500 km in length and flows towards the Bay of Bengal.The headwaters of the river Ganga are called the ‘Bhagirathi’ and are fed by Gangotri glacier in the Himalayas. At Devprayag, it is joined by the Alaknanda river. In Haridwar it emerges from the mountains onto the plains. From the water divide between the Indus and the Ganga, located at Ambala, the gentle plains stretch out for about 1,800 km till the Sunderban delta. Owing to the very gentle elevation gradient, we find many meanders in the course of the Ganga.
The Gangotri Glacier gives rise to ‘Bhagirathi’ or the headwaters of the river Ganga. It reaches the plains at Haridwar and is joined by many tributaries from the Himalayas. One of them is the river Yamuna, which has its origin at Yamunotri Glacier, joining the Ganga at Allahabad. Apart from enriching the soil, some of its tributaries end up causing floods in the northern plains. After touching West Bengal, the Ganga bifurcates, with the mainstream flowing towards Bangladesh, where the Brahmaputra joins it, forming the Sundarban Delta. In India, only a tributary of the Ganga, namely the Bhagirathi-Hooghly, flows south into the deltaic plains to the Bay of Bengal.
Like the Indus, the Brahmaputra also originates in Tibet, from the east of Mansarovar lake, and is slightly longer than the Indus. Flowing parallel to the Himalayas eastwards, it changes course at Namcha Barwa ,it takes a ‘U’ turn to enter Arunachal Pradesh. In Tibet, the river carries a small volume of water and silt , however in India, it carries a high volume of water and silt deposit in the Brahmaputra rapidly increases after entering the heavy rainfall , giving a braided pattern in the entire length in Assam. and forms many riverine islands. .
Unlike the north Indian rivers the Brahmaputra carries heavy silt that makes the river bed rise, creating new channels and causing floods in the rainy season in Assam and Bangladesh.
Rivers in the Peninsula region
The Western Ghats, running from north to south, act as the water divide in the Indian Peninsula. All the major rivers like the Mahanadi, the Krishna, the Godavari, and the Kaveri flow eastwards to the Bay of Bengal, making deltas at their mouths. The few rivers (the Narmada and the Tapi) that flow westwards, making estuaries, are short, with smaller drainage basins created towards the Arabian Sea. The rivers flowing westwards often create rift valleys and deep gorges, which are very attractive to tourists. Noteworthy among them are the ones created by the river Narmada, viz the ‘Marble rocks’ and the ‘Dhuandhar falls’.
- Godavari Basin:
Amongst the rivers from the Western Ghats flowing eastwards, the Godavari is the longest river running for 1,500 km, eventually draining into the Bay of Bengal and forming the largest river basin in the peninsula.
The Godavari is also called Dakshin Ganga, owing to its length. The Krishna (1,400 km), the Mahanadi (860 km), and the Kaveri (760 km) are the other long rivers draining into the Bay of Bengal and forming relatively large drainage basins.
- Narmada Basin:
Rising in the Amarkantak hills of Madhya Pradesh state, Narmada flows through a deep gorge near Jabalpur. The river covers parts of two states Madhya Pradesh and Gujarat.
- Krishna Basin:
The Krishna river is approximately 1,400 km long and it rises from a spring in the Mahadev range near Mahabaleshwar and the river falls into the Bay of Bengal. The river flows through the states oof Maharashtra, Karnataka and Andhra Pradesh.
- Tapi Basin:
The river originates from the Satpura ranges located in Betul district of Madhya Pradesh. It flows through a basin that covers Maharashtra, Gujarat and Madhya Pradesh. The entire Tapi basin is divided into three sub-basins – upper, middle and lower and also in hilly regions and in plain areas.
- 5. Kaveri Basin:
Kaveri river originates in the Brahmagiri range of the Western Ghats. Its length is around 760 km and the river reaches the Bay of Bengal at Kaveripatnam. The river basin is shared across the status of Karnataka, Kerala, Tamil Nadu and Puducherry.
- 6. Mahanadi Basin:
Mahanadi river is around 860 km long and it originates from the highlands of Chhattisgarh. It reaches the Bay of Bengal after travelling from Chhattisgarh, Maharashtra, Jharkhand, and Odisha.
Lakes of India
India is gifted with many lakes, each with different sizes and features. Some lakes are formed by glaciers and ice sheets, while others are formed during the rainy season like the lakes in the basins of semi-arid regions, some others are formed due to glaciers and ice sheets, and some are due to human activity or river or wind action. Most lakes, however, are perennial and need not depend on rainfall or anything else.
When a meandering river approaches floodplains, portions of it get detached and form u-shaped oxbow lakes. Lagoons in the coastal region get formed by spits and bars. Some of the seasonal inland drainage lakes are high in salt content and can be used to extract salt, for example, the Sambhar Lake in Rajasthan. Otherwise, the lakes are generally freshwater since most originate from the Himalayan region. The Wular lake in Jammu and Kashmir is the largest fresh water lake in India. The Dal lake, Bhimtal, Loktak , Nainital are important freshwater lakes in India. The damming of rivers to generate hydropower has resulted in the formation of lakes such as Guru Gobind Sagar – Bhakra Nangal Project.
Development through Rivers and Lakes
The lakes and rivers play an essential role in economic development. Besides enhancing the aesthetics and offering boating, water sports and recreational activities, lakes help regulate the river flow because it prevents flooding during heavy rainfall and maintains the even flow of the river during the dry season. Lakes balance the aquatic ecosystem, keep the climate moderate, and help harness hydel power.
On the other hand, rivers are the primary source of hydel power. Their prominent role in India is in agriculture, industries and maritime activities. Water being a basic necessity, human settlements most often revolve around rivers particularly in a country like India which is dependent on agriculture.
Pollution in rivers
The overexploitation of rivers in our country is a matter of grave concern. The chapter brings out some facts like the depletion of river volume due to increasing demand for domestic, industrial, agricultural and municipal use. The rivers are the central dump yards for waste, industrial effluents, and untreated sewage. The inherent self-cleaning quality of the rivers takes a big hit with this kind of harmful overload. As a result, the overall quality of the river water degrades, creating health problems for humans, fishes, animals and birds. The Indian government has launched many programmes to preserve the quality and quantity of our rivers.
NCERT Solutions for Class 9 Geography Chapter 3: Exercises & Solutions
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Key Features of NCERT Solutions for Class 9 Geography Chapter 3
The essential features of the NCERT Solutions for Class 9 Geography Chapter 3 are:
- This chapter describes India’s drainage or river system, its origin, characteristics, relief features formed along its path, and the drainage basin.
- The northern Himalayas and other elevated physical features in India are the main origins of the river system.
- Apart from creating new and modifying existing physiographic divisions , the river system also influences our country’s vegetation, soil fertility, forests, occupation, settlements, and climatic systems.
- Lakes are a subset of rivers and are as helpful as rivers in maintaining a healthy environment and building the economy of India.
- The chapter also discusses how development and industrialisation lead to water pollution and environmental degradation.