Context: Tamil Nadu government said it would move the Supreme Court over its due share of Cauvery water from Karnataka, as the neighbouring State has refused to share the water with Tamil Nadu.
About Cauvery River
The river has a total length of around 802 km, and a catchment area of 81,155 sq. km, of which 2,866 sq.km. lie in Kerala, 34,273 sq.km. in Karnataka and 44,016 sq.km. in Tamil Nadu.

Flow of Cauvery
- Cauvery, the Ganga of the South, rises at Thalakaveri, in the Brahmagiri range of hills of the Western Ghats, in Karnataka.
- It receives the Harangi which has been dammed North-West of Mysore.
- Two other tributaries-Hemavathy and Lakshmana-theertha join the Cauvery into the Harangi reservoir.
- The main river continues to flow Eastwards up to Sreerangapatnam and then changes its course South-East wards.
- Then it receives Kabini, an important tributary that originates in the Wyanad district of Kerala.
- Then, it joins with Suvarnavathy and takes a North-Easterly direction, passing the Eastern Ghats at Sivasamudram.
- At Sivasamudram, after flowing through a very narrow gorge, it continues its East-ward journey and forms the boundary between the States of Karnataka and Tamil Nadu for about 64km.
- Below Sivasamudram, it receives the Shimsha, and then Arkavathy, just before entering the territory of Tamil Nadu.
- In Tamil Nadu, the river Cauvery continues to flow Eastwards up to Hogenakal Falls and takes a Southerly course and enters the Mettur reservoir.
- It leaves the Eastern Ghats below Mettur and is joined by Bhavani downstream.
- Cauvery takes a more Easterly course after that and is joined by Noyil, and then by Amaravathy.
- Amaravathy, an important tributary of the Cauvery, has its origin in Kerala, where it is known as Pambar, and carries rich flows in Kerala.
- Below Tiruchirappalli, the Cauvery splits into two branches, which are controlled by the Upper Anicut.
- The Northern branch, called the Coleroon flows in a North-Easterly direction to enter the Bay of Bengal near Porto Novo.
- The Southern branch, however, continues to trek under the name of Cauvery itself. It further divides into Cauvery and Vennar below the Grand Anicut.
- The Cauvery branch descends into the Bay at Pompuhar, North of Tranqobar as an insignificant stream.
The Dispute between Karnataka and Tamil Nadu
The Cauvery water sharing dispute, dating back to the British Raj, remains a contentious issue between Karnataka and Tamil Nadu. Many of the districts in both states are dependent on the Cauvery for irrigation.
- The Cauvery water dispute emerged in 1892 between British-ruled Madras Presidency and the princely state of Mysore over water sharing.
- In 1910, the two states began conceptualising the idea of constructing reservoirs to store the river water.
- The 1924 agreement presided over by the British gave Madras Presidency and the Mysore state the right to use surplus water from river Cauvery.
- As per the agreement in 1924, Tamil Nadu and Puducherry would get 75% of the surplus water, while Karnataka would get 23%. The remaining would go to Kerala.
- There were also restrictions on how much land could be irrigated.
Post-Independence
The challenge of water sharing escalated following the state reorganization in 1956:
- Through the late 20th century, Tamil Nadu was opposed to the construction of dams on the river by Karnataka.
- Karnataka contended that the 1924 agreement’s 50-year term expired in 1974, freeing the state from adhering to the regulations, especially since the river originated in the state.
- Between 1960 and late 1980s, Karnataka built four dams on Cauvery – Hemavati, Harangi, Kabini and Suvarnavathy.
- This became a problem for Tamil Nadu as the state had become dependent on Cauvery water especially huge area of agricultural land in the delta area.
Involvement of Supreme Court (SC) and Tribunal
- Tamil Nadu argued that being the lower riparian state put them in a precarious situation and approached the Supreme Court (SC).
- Karnataka government’s arguments
- Karnataka argued that river water sharing should follow international norms to divide the water in equal proportions.
- Karnataka proposed a 47% water allocation for each state, with the remaining divided equally between Kerala and Puducherry.
- Karnataka government’s arguments
- Tamil Nadu government’s arguments
- Tamil Nadu wanted to stick to the 1924 agreement.
- In 1986, Tamil Nadu’s farmers urged the SC for a tribunal to address water sharing.
- In 1990, the SC directed the Centre to establish a tribunal for inter-state water distribution.
- The Cauvery Water Disputes Tribunal (CWDT) assessed 1980-1990 water inflow to Tamil Nadu.
- In 1991, it ordered Karnataka to provide 205 tmcft annual water and cease irrigated land expansion.
- Karnataka rejected the tribunal’s award and sought an annulment in the Supreme Court.
- The SC struck down the state’s ordinance attempting to nullify the award and went on to uphold the tribunal’s order.
- After which Karnataka said that the state was facing drought and hence could not release water.
- The 1998-formed Cauvery River Authority (CRA), which included the Prime Minister as Chairperson and the Chief Ministers from four states as members, enforced CWDT’s interim order.
- Cauvery Water Disputes Tribunal in 2007 gave out its final award.
- CWDT directed Karnataka to release 192 tmcft annually, including 182 tmcft for Tamil Nadu with 10 tmcft for environment, at Billingundlu border.
- In a distress year, allocated shares shall be proportionately reduced among Kerala, Karnataka, Tamil Nadu and Puducherry.
Constitutional provisions
Part XI of the constitution under the title Relations between the Union and the States provides for Disputes relating to Waters.
Article 262: Adjudication of disputes relating to waters of inter-State rivers or river valleys.
- Parliament may by law provide for the adjudication of any dispute or complaint with respect to the use, distribution or control of the waters of, or in, any inter-State river or river valley.
- Notwithstanding anything in this Constitution, Parliament may by law provide that neither the Supreme Court nor any other court shall exercise jurisdiction in respect of any such dispute or complaint as is referred to in clause (1).
Seventh Schedule
Entry 56 of List I: Regulation and development of inter-State rivers and river valleys to the extent to which such regulation and development under the control of the Union is declared by Parliament by law to be expedient in the public interest.
Entry 17 of List II: Water, that is to say, water supplies, irrigation and canals, drainage and embankments, water storage and water power subject to the provisions of entry 56 of List I.
Provision used by Courts
- Tamil Nadu filed a preliminary complaint in 2001 of Article 131, in which it stated that interim measures were not effectively regulated.
- The States of Karnataka, Tamil Nadu and Kerala, disturbed by the decision of the Cauvery Water Dispute Tribunal in 2007, have applied for a special permit pursuant to Article 136. The Supreme Court accepts them.
Article 131: Original jurisdiction of the Supreme Court
Subject to the provisions of this Constitution, the Supreme Court shall, to the exclusion of any other court, have original jurisdiction in any dispute
- Between the Government of India and one or more States;
- Between the Government of India and any State or States on one side and one or more other States on the other;
- Between two or more States
Art 136: Special leave to appeal by the Supreme Court
- Notwithstanding anything in this Chapter, the Supreme Court may, in its discretion, grant special leave to appeal from any judgment, decree, determination, sentence or order in any cause or matter passed or made by any court or tribunal in the territory of India.
- Nothing in clause (1) shall apply to any judgment, determination, sentence or order passed or made by any court or tribunal constituted by or under any law relating to the Armed Forces.
Inter-State River Water Disputes Act, 1956
In Pursuant to the power conferred by the Constitution under Article 262, Parliament has enacted the Inter-State Water Disputes Act, 1956. Following are Its main features:
- Filing of dispute: A State Government which has a water dispute with another State Government requests the Central Government to refer the dispute to a tribunal for adjudication.
- Scope for negotiations: The Central Government, if it is of the opinion that the dispute cannot be settled by negotiation, refer the dispute to a Tribunal.
- Tribunal and its composition: As laid down by the act It consists of a chairman and two other members, nominated by the Chief Justice of India from among persons who, at the time of such nomination, are Judges of the Supreme Court or High Court.
- Appointment of Assessor: Central government in consultation with the Tribunal can appoint assessors to advise it in the proceedings before it.
- Investigation and Report: With the reference being made by the Central Government, the Tribunal investigates the matter and makes its report, embodying its decision. The decision is to be published by the centra government and is to be final and binding on the parties.
- Bar on Courts: Jurisdiction of the Supreme Court and other courts, in respect of the dispute referred to the Tribunal, is barred.
- Formulation of scheme: Central Government may frame a scheme, providing for all matters necessary to give effect to the decision of the Tribunal. It can provide for establishing an authority for implementing the scheme. (Section 6A)
- Dissolution of Tribunal: The Central Government dissolves the Tribunal after it has forwarded its report and the Central Government is satisfied that no further reference to the Tribunal would be necessary.
The River Boards Act 1956
The River Boards Act, 1956, provides for the establishment of River Boards, for the regulation and development of inter-State rivers and river valleys.
- Establishment: The Central Government can establish a Board for “advising the Government of state”when a request is received from a State Government or otherwise.
- Establishment: The established board deals in relation to matters concerning the regulation or development of an inter-State river or river valley, or any specified part as notified by the Central Government.
- Different Boards may be established for different inter-State rivers or river valleys.
- The Board consist of the Chairman and such other members as the Central Government thinks fit to appoint.
- The appointed member must have special knowledge and experience in irrigation, electrical engineering, flood control, navigation, water conservation, soil conservation, administration or finance.
- Functions of the Board: As set out in the Act, they are very wide, covering conservation of the water resources of the inter-State river, schemes for irrigation and drainage, development of hydro-electric power, schemes for flood control, promotion of navigation, control of soil erosion and prevention of pollution.
- All functions of the Board are advisory and not adjudicatory.
- The Board is directed to consult all the Governments concerned and to secure agreement among such governments, as far as possible. (Section 14(3))
- Formulation of scheme: The Board is empowered to frame schemes, obtain comments from the interested Governments and finalise a scheme. (Section 15(2)).
- The schemes so framed are not mandatory to implement, they are of an advisory nature. (Section 15(5)).
- Central Assistance: The Central Government can “assist the state Governments interested”, in taking such steps as may be necessary, for execution of the scheme. (Section 15(6))
- Arbitration: The act provides for arbitration in the listed matters where any dispute or difference arises between two or more Government interested. (Section 22)