Why in News?
Tamil Nadu Minister for Water Resources Duraimurugan said that there is no scope for talks with Karnataka over Tamil Nadu’s demand for its rightful share of Cauvery water recently.
Interstate (River) Water Disputes (ISWDs) are a continuing challenge to federal water governance in India. Rooted in constitutional, historico-geographical, and institutional ambiguities, they tend to become prolonged conflicts between the states that share river basins.

Cauvery Water Dispute:   
It involves Tamil Nadu, Kerala, Karnataka, and Puducherry.
The origin of the dispute extends back 150 years to two arbitration agreements signed in 1892 and 1924 by the Madras presidency and Mysore.
It entailed the principle that the upper riparian state must acquire the consent of the lower riparian state for any construction activity on the river Cauvery, such as the construction of a reservoir.
 
Recent Progression: 
Karnataka began diverting water into its four newly constructed reservoirs without Tamil Nadu's consent in 1974, resulting in a dispute.
To resolve the dispute, the Cauvery Water Disputes Tribunal (CWDT) was constituted in 1990. It took 17 years for the tribunal to issue its final order (2007) on how Cauvery water should be divided among the four riparian states under normal rainfall conditions.
The Central Government established the CWDT in accordance with section 4 of the Inter-State River Water Disputes Act of 1956.
In difficult years, a pro-rata basis shall be utilised, the document stipulated. The government again waited six years before announcing the decree in 2013.
This was challenged in the Supreme Court, which ordered Karnataka to release 12,000 cusecs of water to Tamil Nadu, resulting in protests throughout the state.
In 2018, the Supreme Court rendered its final decision, in which it declared the Cauvery a national asset, mainly upheld the water-sharing arrangements finalised by the CWDT, and reduced Karnataka's water allocation to Tamil Nadu.
According to the Supreme Court, Karnataka would receive 284,75 tmcf, Tamil Nadu 404.25 tmcf, Kerala 30 tmcf, and Puducherry 7 tmcf.
It also mandated that the Cauvery Management Scheme be made public. In June 2018, the central government notified the 'Cauvery Water Management Scheme' and established the 'Cauvery Water Management Authority' and the 'Cauvery Water Regulation Committee' to implement the scheme.
The Mekedatu Reservoir Project seeks to store and provide drinking water to the city of Bengaluru. It is also proposed that approximately 400 megawatts (MW) of electricity will be generated by the initiative.
Tamil Nadu petitioned the Supreme Court in 2018 to block the project, despite Karnataka's position that it would not affect the flow of water to Tamil Nadu.
TN opposes any proposed project in the upper riparian that has not been approved by the SC.

Cauvery River:  
• The Cauvery River (Kaveri) is referred to as "Dakshi Bharat ki Ganga" or "the Ganges of the South"
• The Cauvery River originates at an elevation of 1,341 metres near the village of Cherangala in the Kodagu (Coorg) district of Karnataka at Talakaveri on the Brahmagiri range.The total length of the river from its source to its mouth is 800 kilometres.
• Before emptying into the Bay of Bengal south of Cuddalore, Tamil Nadu, the river divides into a large number of distributaries, forming a wide delta known as the "garden of southern India"
• It is bounded by the Western Ghats on the west, by the Eastern Ghats on the east and the south, and by the ridges separating it from the Krishna basin and Pennar basin on the north. 
• The Nilgiris, an offshore of the Western ghats, extend eastwards to the Eastern ghats and divide the basin into two natural and political regions. There are primarily black soils, red soils, laterites, alluvial soils, forest soils, and mixed soils in the basin. Large portions of the basin are dominated by red soils. In delta regions, alluvial substrates are present.
• Karnataka's basin receives precipitation primarily from the S-W Monsoon and secondarily from the N-E Monsoon. The basin in Tamil Nadu receives ample North-East Monsoon runoff.
Its upper catchment area receives summer precipitation from the south-west monsoon, while its lower catchment area receives winter precipitation from the retreating north-east monsoon.It is therefore almost a perennial river with relatively less fluctuating flow, and it is extremely useful for irrigation and hydroelectric power generation.
Around Sivasamudram are the picturesque Sivasamudram Falls, which drop 100 metres and attain a width of 300 metres during the monsoon season.
• The falls supply Mysore, Bengaluru, and the Kolar Gold Fields with hydroelectric power.Consequently, the Cauvery is one of the most effectively regulated rivers, with 90 to 95 percent of its irrigation and energy production potential already utilised. The river empties into the Bay of Bengal. 66.21% of the entire area of the basin is comprised of agricultural land.
  
CONCLUSION
Consensus on river governance must be simultaneously achieved in two levels: federal consensus (at the institutional level) and electoral consensus (for resolution at the site of mass politics). 
A sound solution must acknowledge that the federal dynamics in India needs confidence-building, both between the Centre and states as well as amongst the states. Consensus-building, based on sustained political deliberation, must be carried out in an institutional environment that guarantees fair representation of the states. 
History shows that mutual suspicions have often derailed the process of political negotiations, especially for states ruled by opposing political parties or coalitions, and in the case of states governed by parties opposed to the national ruling party. These animosities have affected the efficacy of the existing institutional mechanisms.
Since “federal consensus” can only be achieved when the parties involved find it politically beneficial, institutional confidence-building is a necessary condition for fostering such consensus for ISWDs. This can lead to an institutional politicisation of the dispute within the federal framework, where the political actors can deliberate at the institutional level, keeping in mind the political feasibility of a possible solution. It remains to be seen whether the RBA, as envisioned in the draft River Basin Management Bill, 2018, can create space for the political actors in the Governing Council.
Now that India has entered the phase of “second dominant party system,” with interactions between the Centre and the Opposition-ruled states becoming increasingly contentious, federal interaction on river water governance must be studied closely.
Electoral consensus is equally important in the states where river water disputes have assumed larger political dimensions of regional identity and autonomy. It can be achieved by the “positive politicisation” of the issue, which can only happen when the electorate is sensitised regarding the tangible economic and ecological costs of prolonged disputes.
 The political discourse of regional identity and culture must be unravelled by bringing to public notice the developmental hindrances, economic losses, and environmental degradation resulting from a lack of a solution to the dispute. However, political parties that are the chief mass mobilisers and agenda-setters will have no immediate incentive for such positive politicisation. 
Instead, other institutions must create the narratives: the media; civil society; academia; and social, political and environmental activists working at the grassroots. To forge an electoral consensus, the gains of a compromise-induced conflict resolution must be made evident to the people and contrasted with potential losses arising from prolonged ISWDs. 
The process of ‘positive politicisation’ of such a bitterly contested issue like river water, despite being tenuous, would give benefits in the long run. This, in turn, will help facilitate federal consensus. In the context of resolving ISWDs, the focus should be on strengthening the existing and evolving institutional mechanisms, and accommodating political sensitivities to find a long-term and mutually amicable path for the governance of interstate river water.

Mains Practice question:
Q. The current condition of interstate river water governance in India warrants a new approach for cooperative federalism and interstate water governance. Discuss the statement.