(I) The Indus System:
This system comprises river Indus and its five tributaries-Chenab, Jhelum, Ravi, Beas and Satluj.
The Indus rises in Tibet at an altitude of 5,180 metres near the Mansarovar Lake and enters Indian Territory in Jammu and Kashmir. It flows through Ladakh, Baltistan and Gilgit to finally emerge out of the hills at Attock. The Indus receives its Himalayan tributaries such as the Gartang, Zaskar, Dras, Shyok, Shigar, Nubra, Gilgit and the Hunza in Jammu and Kashmir. Some of the important tributaries below Attock include the Kurram, Tochi and the Zhob-Gomal.
The collective flow of its well-known Punjab tributaries—Satluj, Beas, Ravi, Chenab and Jhelum goes to make the Panjnad which falls into the mainstream a little above Mithankot. The Indus flows south-westwards across Pakistan to reach the Arabian Sea east of Karachi.
The Indus is considered as one of the largest rivers of the world, with a total length of 2900 kms with the catchment area of 1,165,000 sq. km of which as much as 321,290 sq. kms lies in India. India utilises only 20 per cent of total discharge under the regulations of the Indus water treaty with Pakistan. This river forms a spectacular gorges in the upper reach and pierces the Kailash range several times. This river has largest networks of canal system with fertile plains.
(a) The Jhelum:
The Jhelum is an important tributary of the Indus. It rises from a spring at Verinag, situated in the south-eastern part of the valley of Kashmir. Its Sanskrit name is Vitasta and is called Veth in Kasmir.
It flows from its source of Wular lake and enters a gorges cut by itself in the Pir Pinjal Range. Between Muzaffarabad and Mangla in Pakistan it runs roughly along the Indo-Pakistan border and joins the Chenab near Jhang in Pakistan. Its total length is 400 kms and drainage area is 28,490 kms in India and it flows in India and Pakistan.
(b) The Chenab:
It is called Asikini in Sanskrit and is formed by the confluence of Chandra and Bhaga in H.P., so is called Chandra Bhaga in H.P. It flows north-westwards and runs parallel to Pir Pinjal for some distance. Its length is 1,180 kms and its catchment area is 5,967 sq. kms in India. The main tributary is Tavi.
(c) The Ravi:
It rises west to the Rohtang Pass in the Kullu hills of H.P. and flows between Pir Pinjal and Dhauladhar ranges. Its Sanskrit name is Iravati. It meets Chenab and enters Panchnad. Its length is 725 kms and has a catchment area of about 6,000 sq. kms.
(d) The Beas:
Its Sanskrit name is Vipasha and it rises from the southern end of Rohtang Pass at the height of 4,000 m. It makes the famous Kullu Valley. It is 470 kms long. Its catchment area is about 26,000 sq. kms. It meets the Sutlej near Harike.
(e) The Satluj:
Its Sanskrit name is Shatdru. It originates from Rakas Lake at an altitude of 4,555 m in Tibet. It flows for about 1,050 kms and drains 24,087 kms of area in India. It is very important tributary as it feeds the canal system of Bhakra Nangal Project, Harike and Sirhind.
(f) The Saraswati:
It was once an important tributary of the Indus. Now lost in the sands of the Thar, it is believed that flowing underground; the Saraswati joins the Ganga at her confluence with Yamuna at Prayag at Allahabad. The place where the three rivers meet is known as Triveni Sangam.
(II) The Ganga System:
The Ganga rises in the U.P. Himalayas. The river acquires its name after its headstreams— Alaknanda and Bhagirathi uniting at Devaprayag. The main right bank tributaries of the plain include the Yamuna and the Sone, besides the minor streams of the Tons and the Punpun. On its left bank, the Ganga, however, receives a larger number of tributaries, including the Ramganga, Gomati, Ghaghra, Gandak, Kosi and the Mahananda.
The total length is shared by Uttar Pradesh, Bihar and West Bengal. Beyond Farakka the mainstream of the Ganga flows east-south east-wards into Bangladesh and is known as Padma. In this reach, the river is known as Bhagirathi-Hooghly. Before falling into the Bay of Bengal below Chandipur in Bangladesh, the Padma receives the Brahmaputra, known here as the Yamuna, and the Meghna.
The river has a length of 2,525 kms. It is shared by Uttranchal, and Uttar Pradesh (1450 kms), Bihar (445 kms) and West Bengal (520 kms) The Ganga basin covers about 9, 52,000 km2 in India alone.
(a) The Yamuna:
It is the most important and longest tributary of the Ganga. It has its source in the Yamunotri glacier on the Banderpunch range. Its basin area is 3, 66,223 km2. It joins the river on its right bank at Prayag. The confluence of the Ganga and Yamuna is called Sangam. Agra is an important city situated on the banks of Yamuna. Chambal and Betwa are tributaries of Yamuna and Sone and Damodar are tributaries of the Ganga. The Yamuna drains the areas of Uttranchal, Delhi and Uttar Pradesh.
(b) The Chambal:
It rises near Mhow in the Malwa Plateau of Madhya Pradesh and flows northwards through a gorge upto Kota in Rajasthan. The Gandhisagar dam has been constructed here. It is 960 kms long and it is famous for badland topography called ravines.
(c) The Sharda:
Known by various names Kali in the Himalayas, the Sharda in Pilibhit and Kheri districts and Chauka before it join the right bank of Ghaghara. It runs along the Indo- Nepal boundary and leaves Himalayas at Baramdeo.
(d) The Ramganga:
The river is the left bank tributary of the Ganga. It rises near Nainital and has a length of 690 kms. It meets Ganga near Farrukhabad.
(e) The Gomti:
This is the only tributary river of the Ganga which rises in the plains and not in the hills. It meets the Ganga down Varanasi.
(f) The Ghaghra:
This river rises parallel to the Ganga in U.P. and its source is east of the Ganga. It joins the Ganga near Chapra. It is 1,080 kms long and its catchment area is 127,500 sq. kms. The headwater of the Ghagra is Karnali which is of trans-Himalayan origin.
(g) The Gandak:
It rises near Sino-Nepal border and drains the central part of Nepal. It is called the Narayani in Nepal. It is 425 kms long and drains 45,800 sq. kms. It meets the Ganga near Bankipur in Bihar. It changes its course and causes floods.
(h) The Kosi:
It drains eastern Nepal and enters Saharsa district of Bihar in numerous channels. The river is notorious for shifting its course, depositing silt and causing floods. It joins the Ganga at Keragola.
(i) The Damodar:
It occupies the eastern margins of the Chhotanagpur plateau where it flows through a graben or a rift valley. The Barakar is its main tributary. The Damodar finally joins the Hooghly. River Damodar is known as the Sorrow of Bengal as it causes mass destruction of floods.
(j) The Mahananda:
It is another tributary of the Ganga rising in the Darjiling hills. It joins the Ganga as its last left bank tributary in West Bengal.
(k) The Son:
It is a large south bank tributary of the Ganga, originating in the Amarkantak plateau. After forming a series of waterfalls at the edge of the plateau, it reaches Arrah, west of Patna to join Ganga.
(III) The Brahmaputra River System:
It is formed by the Brahmaputra River which is about 2,700 kms in length. It flows eastwards through Tibet and is known as Tsang-Po. It is also known as Brahmaputra as it turns southwards in Arunachal Pradesh and enters Assam.
It has a long mountain stage and therefore, carries a lot of sediment. When it enters the plains, it slows down suddenly, depositing its load causing it to split into 2 to 3 channels forming island in its course. Such a river is called a Braided River. The Brahmaputra’s tributaries are Tista, Subansiri, Barali, Manas, Dhansiri, Buri and Dihing.