Ganga River System

• The Ganga river system spreads over India, Tibet (China), Nepal and Bangladesh. It is India’s largest river basin, taking in about a quarter of the country.
• Within India, the basin covers Uttar Pradesh, Madhya Pradesh, Rajasthan, Bihar, West Bengal, Uttarakhand, Jharkhand, Haryana, Chhattisgarh, Himachal Pradesh and the Union Territory of Delhi.
• It drains three contrasting regions: the central Himalaya to the north, the northern edge of the Peninsular plateau to the south, and the Ganga plain between them.
• It has long been held holy by Hindus and worshipped as the goddess Ganga. It was declared the National River of India on 4 November 2008.

The Main River

Key Data

• Older State shares of the basin are:

Headstreams and Course

• The Ganga is formed from six headstreams and their five confluences.
• The Alaknanda meets the Dhauliganga at Vishnuprayag, the Nandakini at Nandprayag, the Pindar at Karnaprayag and the Mandakini at Rudraprayag, on its way to join the Bhagirathi. Together they form the main stream.
• The Bhagirathi is treated as the source stream. From Devprayag, the river is called the Ganga.
• Haridwar: the river debouches, meaning it emerges from a confined valley into open land, here from the hills to the plain, after about 280 km.
• Prayagraj (Allahabad): the Yamuna joins it after a further 770 km or so of south and south-east flow.
• Bihar plain: it sweeps about 300 km further east.
• Rajmahal hills: it turns south-east.
• Farakka: the river splits into the Bhagirathi–Hugli in West Bengal and the Padma in Bangladesh, and the name Ganga ends.
  • Goalundo: after about 220 km in Bangladesh, the Padma receives the Brahmaputra, known there as the Jamuna.
  • Chandpur: about 100 km on, it receives the Meghna, and the joined waters reach the Bay of Bengal under that name.
• Sagar Island marks the mouth of the Hugli channel. Its Gangasagar pilgrim site is the river’s traditional meeting point with the sea.
• Narora, in Uttar Pradesh, is known for its Ganga barrage and nuclear power station.
• Important towns on the river: Haridwar, Kanpur, Soron, Kannauj, Allahabad (Prayagraj), Varanasi, Patna, Ghazipur, Bhagalpur, Mirzapur, Ballia, Buxar, Saidpur and Chunar.

• On this map, “Kamneng” is the Kameng, “Diabang” is the Dibang and “Rajmhal” is the Rajmahal hills.

The Five Prayags

Ganga–Brahmaputra Delta

• Before the Bay of Bengal, the Ganga and Brahmaputra build the world’s largest delta, between the Hugli arm in the west and the Padma–Meghna arm in the east.
  • Area is given as 58,752 sq km in older accounts. Current wider definitions, which take in the whole Bengal lowland, give about 1,05,000 sq km.
  • The delta fans out to a width of about 350 km. Its front is highly indented, running about 400 km between the Hugli and Meghna mouths.
• It is a maze of islands and branching channels, and the dense Sundarbans forests clothe its seaward edge.
• Much of it is a low-lying swamp flooded by seawater at high tide.

Headstream Rivers

Alaknanda

• One of the two main headstreams of the Ganga.
• It begins at the confluence and foot of the Satopanth and Bhagirath Kharak glaciers in Uttarakhand, and meets the Bhagirathi at Devprayag.
• Its main tributaries are the Mandakini, Nandakini and Pindar. The Dhauliganga, the Bishenganga and others join it in its upper course.
  • The Pindar rises from the Nanda Devi and East Trisul area and meets it at Karnaprayag. The Mandakini, also called the Kali Ganga, meets it at Rudraprayag.
• The system drains parts of Chamoli, Tehri and Pauri districts.
• Badrinath and the Tapt Kund hot spring stand on its banks.
• Lake Satopanth, near its origin, is a triangular lake at about 4,402 m, named after the Hindu trinity of Brahma, Vishnu and Shiva.

Bhagirathi

• It rises at the foot of the Gangotri glacier, at Gaumukh, at about 3,892 m, at the base of Chaukhamba in Uttarkashi district.
• Its upper catchment is glaciated.
• In its middle course, it cuts spectacular gorges through the granites and crystalline rocks of the central Himalayan axis, and it crosses the Lesser Himalaya the same way.
• The Bheling joins it above Devprayag.
• Gangotri, Uttarkashi and Tehri are its main settlements.

Dhauliganga

• It starts at Vasudhara Tal, described as perhaps the largest glacial lake in Uttarakhand.
• It is among the leading tributaries of the Alaknanda.
• The Rishiganga joins it at Raini.
• It meets the Alaknanda at Vishnuprayag, where it loses its name.
  • The Alaknanda then runs south-west through Chamoli, Maithana, Nandprayag and Karnaprayag to Rudraprayag, where it takes the Mandakini coming from the north.
  • It goes on past Srinagar to Devprayag, where the name Alaknanda ends.
  • The Ganga flows first south, then west, through pilgrim centres such as Rishikesh, and comes down to the plains at Haridwar.
• The Tapovan–Vishnugad hydropower project (520 MW, NTPC) was being built on the Dhauliganga when the flood of 7 February 2021 seriously damaged it.

Rishiganga

• A river of Chamoli district, Uttarakhand.
• It springs from the Uttari Nanda Devi Glacier on Nanda Devi and is also fed by the Dakshini Nanda Devi Glacier.
• It runs through the Nanda Devi National Park and joins the Dhauliganga near Raini.
• Chamoli disaster, 7 February 2021: a rock and ice mass broke away from the Raunthi catchment at high altitude, and the debris flow raced down the Rishiganga and Dhauliganga. It destroyed the 13.2 MW Rishiganga project, damaged Tapovan and caused heavy loss of life.

Major Tributaries of the Ganga River

• Right bank: Yamuna, Tamsa (also called Tons), Karamnasa, Son, Punpun, Falgu, Kiul, Chandan, Ajay, Damodar, Rupnarayan.
• Left bank: Ramganga, Garra, Gomti, Ghaghara, Gandak, Burhi Gandak, Kosi, Mahananda.
• These tributaries of the Ganga include the Yamuna group, with the Chambal, Banas, Sind, Betwa and Ken.
• Most tributaries rise in the Himalaya, and the biggest left-bank rivers, the Ghaghara, Gandak and Kosi, rise beyond or across the main range. They are antecedent, cutting gorges through the mountains.

Ramganga

• A left-bank tributary that drains south-western Kumaun.
• It starts on the southern slopes of Dudhatoli hill, at about 3,110 m, in the Garhwal hills, given variously as Chamoli or Garhwal district.
• It is spring-fed from underground reservoirs.
• Its course through the lower Himalayan hills of Almora shows incised meanders, paired and unpaired terraces, interlocking spurs, waterfalls, rock benches, cliffs and towering ridges.
• It passes through the dun valley of Corbett National Park, and a dam at Kalagarh crosses it near the point where it enters the plain.
• The Khoh, Gangan, Aril, Kosi and Deoha (Gorra) are its tributaries.
• It joins the Ganga near Kannauj, and Bareilly stands on its banks.

Gomti

• It starts at Gomat Taal, formally known as Fulhaar Jheel, near Madho Tanda in Pilibhit, Uttar Pradesh.
• It runs 900–960 km through Uttar Pradesh, sources differing, and meets the Ganga in Ghazipur district.
• The Markandey Mahadeo temple stands at its meeting point with the Ganga.
• The Sai is its main tributary, joining near Jaunpur.
• Lucknow, Lakhimpur Kheri, Sultanpur and Jaunpur lie along it. It divides Jaunpur city into two equal halves and widens there.
• It is a plains river fed by groundwater and rain, not by snow.

Ghaghara

• It rises in the glaciers of Mapchachungo, near Gurla Mandhata and south of Lake Manasarovar (Mansarovar) on the Tibetan plateau.
• It is also called the Karnali or Kauriala. It is a perennial, trans-boundary river.
• It cuts through the Himalaya in Nepal, in a run of steep defiles, and receives the Sarda at Brahmaghat in India.
• It is a major left-bank tributary of the Ganga and joins it near Chhapra in Bihar, after 1,080 km.
• It is the main source of water in Barabanki district.
• Tributaries: the Rapti, Chhoti Gandak, Sarda and Sarju are the main ones.
  • On the plain, it divides into branches, of which the Koriyab and Garwa are the chief, and they reunite in Bahraich district.
  • It then crosses Gorakhpur, Deoria, Azamgarh and Ballia as a divided stream over wide sands, with sudden bends.
• Basin: about 45% in India, the rest in Nepal and Tibet. Floods are frequent and it has moved its course several times.

Sarda

• The Kali rises near Kalapani, at about 3,600 m, near the Lipulekh Pass in Pithoragarh district, on the Kailash Manasarovar Yatra route. The river takes its name from the temple of the goddess Kali there.
• It is called Mahakali in Nepal and forms the India–Nepal boundary for most of its mountain course.
  • It flows in a gorge through the hills.
• It reaches the plains near Tanakpur, is called the Sarda or Chauka there, and flows south-east to the Ghaghara.
• The Goriganga rises from the Milam glacier. It is sometimes equated with the Sarda and placed in the Nepal Himalaya, but Milam is in the Pithoragarh Himalaya of Uttarakhand, and the Goriganga joins the Kali at Jauljibi as a tributary.
• The Mahakali Treaty between India and Nepal (signed 1996, in force 1997) has the Pancheshwar project as its centrepiece. The project is still pending.

Sarayu

• Also called the Sarju.
• It rises on a ridge south of Nanda Kot in Bageshwar district, Uttarakhand, and is mentioned in the Vedas and the Ramayana.
• Two streams carry the name:
  • The upper Sarayu of Kumaun joins the Kali at Pancheshwar.
  • The lower Ghaghara in Uttar Pradesh is also called the Sarayu. This is the river at Ayodhya, where thousands bathe on Ram Navami, so it is often listed as a left-bank tributary of the Ghaghara.

Rapti

• It rises south of a prominent east–west ridge, midway between the western Dhaulagiri Himalaya and the Mahabharat Range in Nepal.
• The main stream begins as a spring on the southern slopes of the Lower Himalaya, and the river is fed essentially by groundwater.
• Recurrent floods earned it the nickname “Gorakhpur’s Sorrow”.
• Left-bank tributaries: Lungri Khola, Jhimruk Khola, Ami and Rohini. Right bank: Arun Khola.

Gandak

• It forms from the Kali Gandak and the Trisuli, which rise in the Great Himalayan Range in Nepal. Its source zone lies near the Tibet–Nepal border. The Mayangadi and Bari also feed it.
• From their junction to the Indian border it is called the Narayani.
• It enters the plains at Tribeni and joins the Ganga at Sonepur, opposite Patna, near Hajipur. Total winding length is about 765 km, about 425 km of it in India.
• It drains about 46,300 sq km, only 7,620 sq km in India.
• The Burhi Gandak flows parallel to it on the east.
• Its upper catchment is bleak and desolate, lying in the rain shadow of the Himalayan range.
• Its middle and lower courses run through V-shaped valleys and incised meanders, with paired and unpaired terraces on either side.

Burhi Gandak

• This river rises at Chautarwa Chaur near Bisambharpur, in West Champaran district, Bihar.
• Length is given as 320 km in most current sources. Some older accounts carry 610 km, with a basin of 12,200 sq km, from a source in the Sumesar hills. Current data give about 10,150 sq km.
• It first flows through East Champaran. After about 56 km it turns south, where the Dubhara and Tour join it.
• It then runs south-east through Muzaffarpur district for about 32 km.
• It flows parallel to and east of the Gandak, in an old channel, and joins the Ganga opposite Munger (Monghyr).
• Tributaries: Masan, Balor, Pandai, Sikta, Tilawe, Tiur, Dhanauti, Kohra and Danda.
• Samastipur stands on it.
• There is no major or medium project on the Burhi Gandak system.

Kosi

• Called the Saptakoshi for its seven Himalayan streams, it is an antecedent, trans-boundary river of Nepal and India.
  • The seven are the Indrawati, Bhote (Sun) Koshi, Tama Koshi, Likhu, Dudh Koshi, Arun and Tamor.
  • They gather into three: the Sun Kosi from the west, the Arun from the north and the Tamor from the east, which unite at Triveni north of the Mahabharat Range. Together they pass a narrow gorge at Chatra and enter the Nepal Tarai.
• Some rivers of the system, including the Arun, Sun Kosi and Bhote Koshi, rise in Tibet.
• It runs about 720–729 km and joins the Ganga at Kursela in Katihar district, as one of its largest tributaries.
  • Older accounts give 730 km as the length in India, which is too long. It is close to the river’s whole length.
• Mount Everest and Kanchenjunga both lie in its catchment.
• The Bagmati is an important tributary.
• Unstable course:
  • Over the last 250 years, the channel has moved about 120 km from east to west. Heavy monsoon silt is the main cause, and this earned it the name “Sorrow of Bihar”. Over 10,000 sq km of farmland has been turned to waste by sand.
  • The Kosi Barrage near Hanuman Nagar (Bhimnagar) in Nepal, completed in the 1960s, and embankments built jointly by India and Nepal were meant to tame it.
  • 18 August 2008: the eastern embankment breached at Kusaha, 12 km above the barrage, at a flow far below the design level. The river jumped about 120 km east. Silt had raised its bed well above the land outside.

Son River

• The Son is 784 km long. It rises near Amarkantak in Madhya Pradesh, just east of the Narmada’s head, at about 600 m.
• It flows north-north-west through Madhya Pradesh before turning sharply east on meeting the south-west to north-east Kaimur Range.
• It runs along the Kaimur hills, east-north-east through Uttar Pradesh, Jharkhand and Bihar, and joins the Ganga just above Patna, about 16 km above Danapur.
• Geologically, the lower Son valley extends the Narmada valley, and the Kaimur Range extends the Vindhya.
• Dehri is the main town on it.
• Basin area is about 71,259 sq km. Flow swings widely with the season, with little water in the dry months.
• Tributaries:
  • Right bank: Gopad, Rihand, Kanhar and North Koel.
  • Left bank: Ghaggar (a small local stream of this name), Johila and Chhoti Mahanadi.
  • The Rihand and North Koel are the chief tributaries. The area is largely forested and thinly populated.

Rihand

• It rises in the Matiranga hills, south-west of the Mainpat plateau, at about 1,000 m in Chhattisgarh.
• The river and its tributaries form a fertile plain in the central part of the district, from around Ambikapur to Lakhanpur and Pratappur.
• It then flows north into Sonbhadra district of Uttar Pradesh and joins the Son.
• Tributaries: Mahan, Morana (Morni), Geur, Gagar, Gobri, Piparkachar, Ramdia and Galphulla.
• The Rihand Dam was built near Pipri in Sonbhadra district, in Mirzapur division, in 1962 for hydropower. Its reservoir is Govind Ballabh Pant Sagar.

North Koel

• This 260 km river rises on the Ranchi plateau and enters Palamau division below Netarhat, near Rud.
• It flows nearly due west for about 30 km, then turns north at almost a right angle through a gorge at Kutku, crosses the middle of the district and falls into the Son a few miles north-west of Haidarnagar.
• With its tributaries, it meanders through the northern part of Betla National Park.
• Principal tributaries: Auranga, Amanat and Burha.

Damodar

• It starts in the Chotanagpur hills and runs along a rift valley.
• Past Bankura and Burdwan it joins the Hugli about 48 km below Kolkata. The Barakar is its largest feeder.
• It is 541 km long with a 25,820 sq km catchment.
• Past floods earned it the name “Sorrow of Bengal”, and it became the base of the Damodar Valley Corporation scheme of flood control.

Mahananda

• It rises in the Darjeeling hills and is the last left-bank tributary of note before the Ganga enters Bangladesh.

The Ganga in Water Planning and Sharing

Ganga Waters Treaty

• Farakka Barrage was built to divert flow into the Hugli, to flush silt and keep Kolkata port navigable.
• The treaty of 12 December 1996 with Bangladesh shares the dry-season flow at Farakka for 30 years, with 35,000 cusecs guaranteed to each side in alternate ten-day periods of the leanest weeks.
• Current status: the treaty expires on 12 December 2026 and has no automatic extension clause.
  • As of October 2026, Bangladesh seeks a new agreement. India says the matter belongs to the Joint Rivers Commission.
  • Bihar is demanding a say, citing silting behind the barrage.
• The river itself floods Bihar’s plain in the monsoon. The eastern tributaries add large silt loads, which raises the question of floods in the middle and lower Ganga plain.

Ganga–Cauvery Link

• Kanuri Lakshmana Rao proposed a Ganga–Cauvery link in the 1970s as a national water grid. It was to pump flood water from a Patna barrage into a 2,640 km canal, drawing 60,000 cusecs for about 150 days a year.
• Much of that water would have had to be lifted by over 450 m, which counted heavily against it. The present programme for interlinking rivers follows different alignments.

Cleaning the Ganga

Namami Gange Yojana

• Namami Gange, officially the Integrated Ganga Conservation Mission, is the Union Government’s programme to clean and protect the river in one integrated way. It combines existing efforts into a single action plan.
• Funding:
  • The 2014–15 budget set aside ₹2,037 crore for it.
  • It was launched with a non-lapsable, centrally funded corpus of ₹20,000 crore and nearly 288 projects at the start.
• Administration: it falls under the Department of Water Resources, River Development and Ganga Rejuvenation, Ministry of Jal Shakti.
  • The National Mission for Clean Ganga (NMCG) implements it, with state counterparts called State Programme Management Groups (SPMGs).
  • NMCG is the implementing wing of the National Ganga Council, set up in 2016 to replace the National Ganga River Basin Authority (NGRBA).
  • Other partners: the Environment, Urban Development, Shipping, Tourism and Rural Development ministries.
• Coverage at launch: 8 States, 47 towns and 12 rivers. Over 1,632 gram panchayats on the banks were to become open-defecation-free by 2022. Its prime focus is the involvement of people living on the banks.
• Current position:
  • Phase I ran to March 2021. Phase II was sanctioned to March 2026.
  • By mid-2026, 524 projects worth about ₹43,031 crore were sanctioned and 363 completed.
  • Sewerage work covers 218 projects with 6,610 MLD capacity, of which about 4,263 MLD had been created or rehabilitated.
  • Spending stood at over ₹21,550 crore. About half the sanctioned money was therefore still to be spent.
• Planned measures:
  • River-centred urban planning, with better citizen connection through ghats and riverfronts.
  • Wider sewerage coverage in 118 urban habitations on the banks.
  • Ganga-specific River Regulatory Zones.
  • Rational farming practices and efficient irrigation.
  • A Ganga Knowledge Centre.
• Pollution control through:
  • Treatment of wastewater in drains by bio-remediation, in-situ treatment and innovative technologies.
  • Municipal sewage and effluent treatment plants.
  • Immediate steps to stop sewage inflow.
  • A public–private partnership approach.
• A Territorial Army Ganga Eco-Task Force of 4 battalions was planned. A Ganga Task Force now works in Uttar Pradesh on tree planting, awareness and patrolling.

Other Initiatives Taken

• Ganga Action Plan (GAP): the first river action plan, approved in 1985, under what was then the Department of Environment. It aimed to improve water quality by intercepting, diverting and treating domestic sewage, first in 25 towns of Uttar Pradesh, Bihar and West Bengal.
  • The National River Conservation Plan extended this approach, and the Ganga was taken up further under GAP Phase II.
• National Ganga River Basin Authority (NGRBA): formed by the Government of India on 20 February 2009, under Section 3 of the Environment (Protection) Act, 1986.
  • The Ganga’s status as National River came a little earlier, from the announcement of 4 November 2008, not from the Authority itself.
• Clean Ganga Fund: formed in 2014 to clean the river, set up waste treatment plants and conserve its biodiversity.
• Bhuvan-Ganga Web App: brings the public into monitoring pollution entering the river.
• Ban on Waste Disposal: the National Green Tribunal barred the disposal of waste in the Ganga in 2017.
• Biodiversity: a national survey counted about 6,324 Ganges river dolphins, and threatened turtles and gharial are being restored in the Ganga and its tributaries.