The east-flowing Peninsular rivers: Mahanadi, Godavari, Krishna and Kaveri

Detail

Common features of the east-flowing rivers

• East-flowing Peninsular rivers: rivers of the Deccan plateau that flow east into the Bay of Bengal. The plateau tilts from the Western Ghats (Sahyadri) in the west down towards the east coast, so most of its large rivers run east.
• Why they build deltas and not estuaries:
• The rivers are long and carry a lot of silt.
• The east coast has a gentle slope and the Bay of Bengal has fairly weak tides.
• Silt settles at the mouth faster than waves can remove it. This builds a delta (a fan-shaped plain of river deposits where a river splits into many branches before it meets the sea).

• The west-flowing Narmada and Tapi are different. They flow through rift valleys (long valleys formed where land sinks between faults) and form estuaries (wide river mouths where the sea comes in) instead of deltas.

• Why they are seasonal: these rivers are rain-fed. They have no glaciers to feed them, so their flow is high in the monsoon and low in summer. The Kaveri is the one exception, explained below.

• Graded profile: the plateau is old and stable, so most of these rivers flow in wide, shallow, mature valleys with gentle slopes.

River	Origin	Length	Basin area	Mouth / delta
Mahanadi	Sihawa, Dhamtari (NCERT: Raipur), Chhattisgarh	851 km	1.42 lakh sq km	Delta near Cuttack, Odisha
Godavari	Trimbakeshwar, Nashik, Maharashtra	1,465 km	3.13 lakh sq km	Delta below Rajahmundry, Andhra Pradesh
Krishna	Mahabaleshwar, Sahyadri, Maharashtra	1,401 km	(second largest east-flowing)	Delta below Vijayawada, Andhra Pradesh
Kaveri	Talakaveri, Brahmagiri hills (1,341 m), Kodagu, Karnataka	800 km	81,155 sq km	Delta in Thanjavur area, Tamil Nadu

Mahanadi

• Origin and course:
• It rises near Sihawa in Dhamtari district of Chhattisgarh (NCERT: Raipur district; Dhamtari was later carved out of Raipur).

• It flows east through Chhattisgarh and Odisha and enters the Bay of Bengal.

• Size:

• Length: 851 km.
• Basin: 1.42 lakh sq km, of which 53% is in Madhya Pradesh and Chhattisgarh and 47% in Odisha.

• The basin covers mainly Chhattisgarh and Odisha, with small parts in Jharkhand and Maharashtra [8].

• Main tributaries: the Seonath, Hasdeo, Mand and Ib on the left bank, and the Tel and Jonk on the right bank.

• Navigation: some navigation is possible in the lower course.
• Hirakud dam:
• It was completed in 1957 across the Mahanadi near Sambalpur, Odisha.

• It is one of the longest earthen dams in the world. It was built for flood control, irrigation and power.

• Delta:

• The delta begins near Cuttack.

• Chilika Lake lies just south of it. Chilika is a lagoon, which means a shallow body of salty water cut off from the sea by a sand bar.

• Interlinking: the national river-linking plan proposes a Mahanadi (Manibhadra)–Godavari (Dowlaiswaram) link to carry surplus Mahanadi water south [9].

• Dispute:
• Odisha objected to barrages built upstream by Chhattisgarh.
• After a Supreme Court order of 23 January 2018, the Centre set up the Mahanadi Water Disputes Tribunal on 12 March 2018 under Section 4 of the Inter-State River Water Disputes Act, 1956 [4].

Godavari: the "Dakshin Ganga"

• Why it is called "Dakshin Ganga" (Ganga of the South): it is the largest Peninsular river system, both in length and in basin area.
• Origin: it rises at Trimbakeshwar in Nashik district, Maharashtra, on the eastern slopes of the Western Ghats.
• Size:
• Length: 1,465 km.

• Basin: 3.13 lakh sq km. Of this, 49% is in Maharashtra and 20% in Madhya Pradesh and Chhattisgarh. The rest is in Andhra Pradesh. Since 2014 a large part of this "rest" lies in Telangana.

• Tributaries:

• The main ones are the Penganga, Indravati, Pranhita and Manjra.
• The Pranhita carries the joint waters of the Wardha and the Wainganga.
• The Indravati drains the Bastar region of Chhattisgarh.

• The Manjra joins from the right (south) bank.

• Lower course:

• The river cuts a gorge (a narrow, steep-sided valley) through the Eastern Ghats near Polavaram.
• Below Polavaram it floods heavily.
• It is navigable only in the delta.

• After Rajahmundry it splits into branches and forms a large delta. The Godavari and Krishna deltas together make one of India's main rice bowls.

• Polavaram Irrigation Project:

• It is a multi-purpose dam near Ramayyapeta village, Polavaram mandal, West Godavari district, Andhra Pradesh [6].
• It was planned under the Godavari Water Disputes Tribunal award of 1980 [6].
• Its planned benefits are irrigation for 4.36 lakh ha, 960 MW of hydropower and drinking water for 28.50 lakh people [6].
• It will also divert 80 TMC (thousand million cubic feet) of Godavari water into the Krishna basin. This makes it an inter-basin transfer [6].
• It was declared a National Project under Section 90 of the Andhra Pradesh Reorganisation Act, 2014 [6][7].
• The Centre executes the project and gets its clearances. It pays 100% of the remaining cost of the irrigation part, counted as on 1 April 2014 [6][7].
• Submergence dispute: the reservoir will flood land in Odisha and Chhattisgarh as well as Telangana, where many tribal villages lie. These states oppose the extent of flooding.

Krishna

• Rank: it is the second largest east-flowing Peninsular river, after the Godavari.
• Origin and course:
• It rises near Mahabaleshwar in the Sahyadri (Western Ghats), Maharashtra.
• It flows through Karnataka, Telangana and Andhra Pradesh.

• It enters the Bay of Bengal after forming a delta below Vijayawada.

• Length: 1,401 km.

• Tributaries:
• The main ones are the Koyna, Tungabhadra and Bhima.
• The Koyna is home to the Koyna dam in Maharashtra. A large earthquake struck there in 1967.
• The Tungabhadra is formed by the Tunga and the Bhadra in Karnataka.

• Other tributaries are the Ghataprabha, Malaprabha and Musi. Hyderabad stands on the Musi.

• Basin share: 27% Maharashtra, 44% Karnataka, 29% Andhra Pradesh and Telangana.

• Major dams:
• Srisailam, upstream, on the Andhra Pradesh–Telangana border.

• Nagarjunasagar, downstream. It is one of the largest masonry dams in the world.

• Water dispute:

Stage	Year(s)	What happened
KWDT-I (Bachawat tribunal)	Award 1976	Shared the water among Maharashtra, Karnataka and undivided Andhra Pradesh. Its decision is notified and binding [3]
KWDT-II (Brijesh Kumar tribunal)	Reports 2010 and 2013	Re-allocated the water, including the surplus flows
After Telangana was created	2014 onward	Section 89 of APRA, 2014 extended KWDT-II to make project-wise allocations and set an operational protocol for releasing water in deficit years [5]
Telangana's complaint	2018 onward	In 2018 Telangana asked for the dispute to be limited to Telangana and Andhra Pradesh. The tribunal's term has been extended year after year [5]

Kaveri

• Origin: it rises at Talakaveri in the Brahmagiri hills (1,341 m), Kodagu (Coorg) district, Karnataka.
• Size:
• Length: 800 km.

• Basin: 81,155 sq km, of which 3% is in Kerala, 41% in Karnataka and 56% in Tamil Nadu.

• Tributaries:

• The main ones are the Kabini, which rises in Wayanad, Kerala, and the Bhavani and Amravati, which flow in Tamil Nadu.

• Others are the Hemavati, Shimsha and Arkavathi in Karnataka.

• Why the Kaveri flows all year (a perennial river):

• Upper catchment (Karnataka, Western Ghats): rain comes from the south-west monsoon in summer (June to September).
• Lower catchment (Tamil Nadu coast): rain comes from the north-east monsoon in winter (October to December).

• Result: the river gets water in two seasons. Its flow changes less than that of any other Peninsular river. This makes it very useful for irrigation and hydropower.

• Landmarks from source to sea: 1. Krishnaraja Sagar (KRS) dam, near Mysuru, Karnataka. 2. Shivanasamudra falls, Karnataka. The river splits around an island here, and India's early hydroelectric station was built at the falls (1902). 3. Hogenakkal falls, where the river enters Tamil Nadu. 4. Mettur dam (Stanley reservoir), Salem district, Tamil Nadu. 5. Srirangam, a river island near Tiruchirappalli formed between the Kaveri and its branch, the Kollidam (Coleroon). 6. Kaveri delta in Thanjavur, a rich rice area called the "garden of south India". The ancient Grand Anicut (Kallanai) stands on the river here.

• Kaveri water dispute:

• 2007: the Cauvery Water Disputes Tribunal (CWDT) gave its final award.
• 16 February 2018: the Supreme Court gave its judgment in State of Karnataka v. State of Tamil Nadu. It changed the award, and the award then merged with the judgment. The CWDT was dissolved on 16 July 2018 [3].
• 2018: the Centre framed the Cauvery Water Management Scheme, 2018 under Section 6A of the Inter-State River Water Disputes Act, 1956. The scheme created the Cauvery Water Management Authority (CWMA) and the Cauvery Water Regulation Committee [2].
• The CWMA controls storage, sharing and release of Kaveri water so that the 2018 judgment is followed [2].

Smaller east-flowing rivers (north to south)

River	Rises in	Flows through / notes
Subarnarekha	Ranchi plateau, Jharkhand	Jharkhand, West Bengal, Odisha
Baitarani	Keonjhar hills, Odisha	Shares a joint delta with the Brahmani
Brahmani	Formed by the South Koel and Sankh, near Rourkela	Odisha; the Bhitarkanika mangroves lie in its delta area
Vamsadhara	Odisha	Odisha and Andhra Pradesh
Pennar	Nandi hills, Karnataka	Karnataka and Andhra Pradesh; it lies in a rain-shadow zone, so it carries little water
Palar	Karnataka plateau	Karnataka, Andhra Pradesh, Tamil Nadu; reaches the sea south of Chennai
Vaigai	Varushanad hills, Tamil Nadu	Madurai; ends near Palk Bay

Prelims Hooks

• Origin pairs: Mahanadi to Sihawa (Chhattisgarh), Godavari to Trimbakeshwar (Nashik), Krishna to Mahabaleshwar, Kaveri to Talakaveri (Brahmagiri hills, Kodagu).
• Order by length: Godavari (1,465 km) > Krishna (1,401 km) > Mahanadi (851 km) > Kaveri (800 km).
• Tributary pairs: Indravati, Pranhita, Penganga and Manjra go to the Godavari. Koyna, Bhima and Tungabhadra go to the Krishna. Kabini, Bhavani and Amravati go to the Kaveri.
• Trap: the Kaveri basin covers three states plus Puducherry (Karaikal). The largest share is Tamil Nadu (56%), not Karnataka (41%).
• The Kaveri is the least seasonal Peninsular river because it gets rain from both the south-west and the north-east monsoons.
• Dam–river pairs: Hirakud to Mahanadi, Polavaram to Godavari, Nagarjunasagar and Srisailam to Krishna, KRS and Mettur to Kaveri.
• Polavaram became a National Project under Section 90 of APRA, 2014 [6][7].
• The Mahanadi Water Disputes Tribunal was set up on 12 March 2018, with Odisha versus Chhattisgarh [4].
• The Cauvery Water Management Authority was created under Section 6A of the ISRWD Act, 1956, after the Supreme Court judgment of 16 February 2018 [2].
• Lagoon–delta pair: Chilika lies south of the Mahanadi delta.

Mains Points

• Inter-state water conflicts (GS-I/II/III):
• Rain-fed rivers carry little water in dry years.
• Upstream states (Karnataka, Chhattisgarh, Maharashtra) build dams and barrages.
• Downstream deltas (Tamil Nadu, Odisha, Andhra Pradesh) lose water.
• Tribunals take decades to decide: CWDT 1990–2007, and KWDT-II is still extended year after year [5].

• The CWMA model of a permanent body that carries out the award is a possible template for other basins [2].

• Floods and deltas (GS-III disasters):

• The rivers have a gentle slope and the deltas are low.
• Cyclones from the Bay of Bengal add extra rain.
• The result is severe floods below Polavaram on the Godavari and in the Mahanadi delta.

• Multi-purpose dams such as Hirakud and Polavaram try to combine flood control with irrigation and power [6].

• Interlinking of rivers:

• The Mahanadi and Godavari are treated as "surplus" basins.
• Links such as Mahanadi (Manibhadra)–Godavari (Dowlaiswaram) and Polavaram's 80 TMC transfer to the Krishna aim to move water south to the Krishna, Pennar and Kaveri basins [6][9].

• Concerns include submergence of tribal land, reduced silt reaching the deltas (which can shrink them), and disputes over how much water is truly "surplus".

• Agriculture and economy:

• The deltas of the Kaveri, Krishna–Godavari and Mahanadi are India's main rice belts on the east coast.
• The Kaveri's two-monsoon flow explains its early and intensive use for irrigation, from the Grand Anicut to Mettur.