The rivers in India play an important role in the lives of its people. They provide potable water, cheap transportation, electricity, and the livelihood for many people nationwide. This easily explains why nearly all the major cities of India are located by the banks of rivers. The rivers also have an important role in Hindu Religion and are considered holy by many Hindus in the country.[1]
Seven major rivers along with their numerous tributaries make up the river system of India. The largest basin system pours its waters into the Bay of Bengal; however, some of the rivers whose courses take them through the western part of the country and towards the east of the state of Himachal Pradesh empty into the Arabian Sea. Parts of Ladakh, northern parts of the Aravalli range and the arid parts of the Thar Desert have inland drainage.
All major rivers of India originate from one of the following main watersheds:
eastern Himalayan glaciers in the Indian subcontinent are broadly divided into three river basins, namely the Indus, Ganges and Brahmaputra. The Indus basin has the largest number of glaciers (3500), whereas the Ganges and Brahmaputra basins contain about 1000 and 660 glaciers, respectively.[2] The Ganges is the largest river system in India. However, these rivers are just three among many. Other examples are Narmada, Tapathi, and Godavari.
The Indo gangetic plains are known as Ganga-Satluj Ka Maidaan (गँगा सतलुज का मैदान), this area is drained by 16 major rivers. The major Himalayan Rivers are the Indus, Ganges, and Brahmaputra. These rivers are long, and are joined by many large and important tributaries. Himalayan rivers have long courses from their source to sea (in India Arabian sea and Bay of Bengal).
Following rivers flow from the Aravalli range, both northwards to Yamuna as well as southwards to Arabian Sea.
The major rivers in this system are (in order of merging, from west to east)
Before entering Bangladesh, near Farakka in Malda District, Ganga leaves a distributary Hoogly, 450km (280miles) which provides water for irrigation in West Bengal
The Brahmaputra river originates / starts from Tibet.
See main article: Brahmaputra River and List of rivers by length.
The Indus River originates in the northern slopes of the Kailash range near Lake Manasarovar in Tibet. Although most of the river's course runs through neighbouring Pakistan, as per as regulation of Indus water treaty of 1960, India can use only 20 percent of the water in this river. A portion of it does run through Indian territory, as do parts of the course. The rivers forming Panjnad are Chenab, Satluj, Jhelum, Ravi and Beas These tributaries are the source of the name of the Punjab of South Asia; the name is derived from the panch ("five") and aab ("water"), hence the combination of the words (Punjab) means "land with the water of five rivers". The Indus is 3610km (2,240miles) long.
The major rivers in Indus river system are (in order of their length):
India experiences an average precipitation of 1170mm per year, or about 4000km3 of rains annually. Some 80 percent of its area experiences rains of 50inches or more a year. However, this rain is not uniform in time or geography. Most of the rains occur during its monsoon seasons (June to September), with the northeast and north receiving far more rains than India's west and south. Other than rains, the melting of snow year round over the Himalayas feeds the northern rivers to varying degrees. The southern rivers, however experience more flow variability over the year. For the Himalayan basin, this leads to flooding in some months and water scarcity in others. Despite extensive river system, safe clean drinking water as well as irrigation water supplies for sustainable agriculture are in shortage across India, in part because it has, as yet, harnessed a small fraction of its available and recoverable surface water resource.[8] India harnessed 761km3 (20 percent) of its water resources in 2010, part of which came from unsustainable use of groundwater. Of the water it withdrew from its rivers and groundwater wells, India dedicated about 688km3 to irrigation, 56km3 to municipal and drinking water applications and 17km3 to industry.
According to 2011 report of the Food and Agriculture Organization of the United Nations, India's basin wise distribution of catchment area and utilizable surface water resources is presented in the following table:[9]
| Basin number | River basin unit | Region | Draining into | Catchment area (% of river irrigated India) | Average runoff (km3) | Additional available surface water (km3) | |
|---|---|---|---|---|---|---|---|
| 1.1 | Ganges (GBM) | North | 26.5 | 525.02 | 250 | ||
| 1.2 | Brahmaputra (GBM) | Northeast | 6 | 537.24 | 24 | ||
| 1.3 | Meghna/Barak (GBM) | East | 1.5 | 48.36 | |||
| 2 | Other Northeast rivers | Northeast | 1.1 | 31 | |||
| 3 | Subernarekha | East-southeast | 0.9 | 12.37 | |||
| 4 | Brahmani-Baitarani | East-southeast | Bay of Bengal | 1.6 | 28.48 | 6.8 | |
| 5 | Mahanadi | Central-east | Bay of Bengal | 4.4 | 66.88 | 18.3 | |
| 6 | Godavari | Central | Bay of Bengal | 9.7 | 110.54 | 50 | |
| 7 | Krishna | Central | Bay of Bengal | 8 | 78.12 | 76.3 | |
| 8 | Pennar | Southeast | Bay of Bengal | 1.7 | 6.32 | 58 | |
| 9 | Kaveri | South | Bay of Bengal | 2.5 | 21.36 | 6.9 | |
| 10 | East flowing rivers between Mahanadi and Pennar | Central-east | Bay of Bengal | 2.7 | 22.52 | 19 | |
| 12 | East flowing rivers between Kanyakumari and Pennar | Southeast | Bay of Bengal | 3.1 | 16.46 | 13.1 | |
| 13 | West flowing rivers between Tadri and Kanyakumari | Southwest | 1.7 | 113.53 | 16.7 | ||
| 14 | West flowing rivers between Tapi and Tadri | Southwest | Arabian Sea | 1.7 | 87.41 | 24.3 | |
| 15 | Tapi | Central-west | Arabian Sea | 2 | 14.88 | 11.9 | |
| 16 | Narmada | Central-west | Arabian Sea | 3.1 | 45.64 | 14.5 | |
| 17 | Mahi | Northwest | Arabian Sea | 1.1 | 11.02 | 34.5 | |
| 18 | Sabarmati | Northwest | Arabian Sea | 0.7 | 3.81 | 3.1 | |
| 19 | West flowing rivers between Kutch and Saurashtra | Northwest | Arabian Sea | 10 | 15.1 | 1.9 | |
| 20 | Rajasthan inland basin | Northwest | 0 | Negligible | 15 | ||
| 21 | Indus tributaries | Northwest | 10 | 73.31 | 46 | ||
| Total (per International Treaty) | 100 | 1869.37 |
The main water divide in peninsular rivers is formed by the Western Ghats, which run from north to south close to the western coast. 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 delta at their mouths. The Narmada, Sharavati, Periyar and Tapti are the only long rivers, which flow west and make estuaries.