The term "drainage" refers to an area's river system.

A drainage basin, often known as a river basin, is a region that is drained by a single river system.

A water divide is an upland that divides two drainage systems that are adjacent to each other.

India has two river systems based on origin: the Himalayan rivers and the Peninsular rivers.

Himalayan rivers are rainfed and snowfed, thus they have water all year, making them perpetual.

The upper channel of the Himalayan Rivers experiences intense erosion.

They transport massive amounts of silt and sand in the lower course.

On their way, Himalayan Rivers form meanders, oxbow lakes, and other depositional features.

Peninsular rivers are mostly dependent on rainfall.

The majority of rivers in peninsular India begin in the Western Ghats and run into the Bay of Bengal.

The Himalayan Rivers

A river system is made up of a river and its tributaries.

The Indus, Ganga, and Brahmaputra rivers are the three great Himalayan Rivers.

The Indus River System

The Indus River enters India in the Ladakh area of Jammu and Kashmir after rising near Lake Mansarovar in Tibet.

Kashmir's tributaries include the Zaskar, the Nubra, and the Shyok.

The rivers Satluj, Beas, Ravi, Chenab, and Jhelum join the Indus around Mithankot, Pakistan, and flow south to the Arabian Sea east of Karachi.

The Indus is one of the world's longest rivers, stretching about 2900 kilometers.

According to the Indus Water Treaty of 1960, India and Pakistan distributed water from the Indus River.

The Ganga River System

The Ganga's headwaters, known as the 'Bhagirathi,' are fed by the Gangotri Glacier and join the Alaknanda in Devprayag in Uttarakhand.

Ganga joins Himalayan tributaries such as Ghaghara, Gandak, and Kosi.

The Yamuna River, which flows from the Yamunotri Glacier in the Himalayas, joins the Ganga near Allahabad.

Other tributaries, including Chambal, Betwa, and Son, flow from the Peninsular uplands to join Ganga.

Farukka in West Bengal is the Ganga Delta's northernmost point.

The Ganga is joined by the Brahmaputra to produce the Meghna, which flows through Bangladesh to the Bay of Bengal.

The Sunderban Delta is produced where the Ganga and Brahmaputra rivers meet in the Bay of Bengal.

The Ganga is nearly 2500 kilometers long, with significant meanders in the downstream plains.

The Brahmaputra River System

Originating in Tibet, adjacent to the Indus and Satluj rivers, most of its route is outside of India.

When it reaches Namcha Barwa, it makes a 'U' bend and enters Arunachal Pradesh before continuing on to Assam, where it is joined by other tributaries.

Dibang, Lohit, and Kenula are the tributaries that join the Brahmaputra.

In Assam, the Brahmaputra River has a braided channel that forms several riverine islands. The Brahmaputra River has the world's biggest riverine island.

The Brahmaputra, unlike other north Indian rivers, has massive layers of silt on its bed, forcing the riverbed to rise.

The Peninsular Rivers

The primary water divide in peninsular India is formed by the Peninsular Rivers and the Western Ghats.

The peninsula's principal rivers, the Mahanadi, Godavari, Krishna, and Kaveri, run eastwards into the Bay of Bengal.

The only rivers that run west to form estuaries and discharge into the Arabian Sea are the Tapi and Narmada.

The peninsular rivers' drainage basins are rather limited in size.

The Narmada Basin

Narmada runs across Madhya Pradesh's marble rocks after rising in the Amarkantak hills.

The Narmada River runs westward in a rift valley caused by faulting.

It runs in the shape of a deep valley through the marble cliffs near Jabalpur, and the Dhuadhar falls are lovely spots.

The Tapi Basin

The Tapi Basin is located near Betul, Madhya Pradesh, amid the Satpura mountains.

It, too, runs in a rift valley parallel to the Narmada, although it is considerably shorter.

Tapi flows across three states: Madhya Pradesh, Gujarat, and Maharashtra.

Sabarmati, Mahi, Bharathpuzha, and Periyar are the major west-flowing rivers.

The Godavari Basin

The Godavari Basin begins in the Maharashtra region of Nasik and is the biggest peninsular river, stretching for over 1500 kilometers.

Its vast basin encompasses the majority of Maharashtra, Madhya Pradesh, Orissa, and Andhra Pradesh.

Purna, Wardha, Pranhita, Manjra, Wainganga, and Penganga are tributaries to the Godavari.

The Godavari River empties into the Bay of Bengal.

The Mahanadi River Basin

The Mahanadi River begins in Chhattisgarh and flows through Orissa to the Bay of Bengal.

Maharashtra, Orissa, Jharkhand, and Chhattisgarh share the Mahanadi river basin.

The Krishna Basin

The 1400 km long Krishna river begins near Mahabaleshwar and flows to the Bay of Bengal.

Krishna's tributaries include Bhima, Musi, Ghatprabha, Koyana, and Tungabhadra. Maharashtra, Karnataka, and Andhra Pradesh all share the Krishna basin.

The Kaveri Basin

The Kaveri River rises in the Western Ghats' Brahmagiri range and flows into the Bay of Bengal in Kaveripatnam, sharing its basin with Karnataka, Tamil Nadu, and Kerala.

The river Kaveri creates India's second-largest waterfall, Sivasamudram.

Other minor rivers are the Damodar, Brahmani, Baitarani, and Subarnlekha.

Lakes

Most lakes are permanent, although some only have water during the rainy season.

Some lakes are generated by glacial action and ice sheets, while others may be formed by wind, river movement, and human activity.

A river that meanders across a floodplain creates cut-offs that eventually evolve into oxbow lakes.

Glacial lakes arise when glaciers carve out a basin that is then filled with snowmelt.

Some lakes, such as Wular Lake in Jammu and Kashmir, are the consequence of tectonic activity.

Aside from natural lakes, damming rivers for hydroelectric power generation has resulted in the development of lakes.

Lakes contribute in the regulation of river water flow, the prevention of floods, the development of hydropower, the moderating of climate, the preservation of aquatic ecosystems, the enhancement of natural beauty, the development of tourism, and the provision of recreation.

Role of rivers in the economy

Rivers are natural water sources.

Settlements along the river's banks have grown into cities.

Rivers are utilized for irrigation, shipping, and hydropower generation, all of which are essential for India's agricultural economy.

River Pollution

River water quality is being impacted by rising residential, municipal, industrial, and agricultural demand.

Untreated sewage and industrial effluents are dumped into the river, reducing its ability to self-clean.

Concerns over increased pollution in our rivers prompted the implementation of numerous river-cleaning schemes.