A protest has emerged in Goa following the publication of a scientific paper, “The water budget of the Mahadayi river and its implications for the inter-State dispute”, by scientists and researchers from the CSIR- National Institute of Oceanography (NIO), Goa and the Indian National Centre for Ocean Information Services, Ministry of Earth Sciences, Hyderabad.  

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The legal dispute between Karnataka and Goa over the water sharing agreement from the Mahadayi river has lasted over two decades. Despite the Mahadayi Water Disputes Tribunal’s (MWDT) order five years ago, the matter remains an emotional subject in both the States.   

The paper, published in the Journal of Earth System Sciences by scientists and researchers: K. Anilkumar, D. Shankar and K. Suprit — has assessed the water budget of the Mahadayi river, an inter-State basin on India’s west coast, by using rainfall mapping and rainfall run-off model to allow them to simulate the discharge at any point along the Mahadayi. 

The river, called Mahadayi in Karnataka and Mhadei in Goa, arises in the Western Ghats and flows into the eastern Arabian Sea. This river basin is spread over three States — Goa, Karnataka, and Maharashtra.  

The paper says Karnataka’s plans for diversion of the river as approved by the MWDT would not have much impact on Goa. The diversion from the Kalasa tributary could have “significant impact” but its impact is restricted to the northern part of the Mhadei Wildlife Sanctuary in Goa.  

Scientists recommend that by creating check dams and storage facilities inside the wildlife sanctuary, the ecological impact of the river diversion could be minimised.   

The length of the Mahadayi in Karnataka is 36 km and its length in Goa is 74 km. The Mahadayi basin covers an area of 2,032 sq km of which 380 sq km (18%) is in Karnataka, 72 sq km (4%) in Maharashtra, and 1,580 sq km (78%) in Goa. The tribunal has permitted the Karnataka government to utilise 1.72 tmcft of water from Kalasa nala and 2.18 tmcft from Bhandura Nala (two of the main tributaries of Mahadayi). 

Tillari dam example

The researchers suggest a solution in the paper that Goa and Karnataka can reach an agreement on similar lines to the one Goa has with Maharashtra for the Tillari dam, in which the dam is built upstream on the Maharashtra side, since Goa does not have the space nor the geography to host a large dam without a huge environmental and people cost — and both States have a share of the water.   

For the Kalasa nala, there is a significant impact of the permitted diversion — 1.72 tmcft (48.7 Mcum) by the Mhadei Water Dispute Tribunal in the northern part of the Mhadei Wildlife Sanctuary, but the impact on the Mahadayi discharge on the Mandovi estuary is less than the natural variability. Similarly, the diversion of 2.18 tmcft (61.73 Mcum) from the Bhandura nala as permitted by the tribunal will only have a minor impact on the (river’s) discharge at the Goa–Karnataka border, the paper said.  

The MWDT was set up in 2010 following the failure of the States to reach an agreement.  

The tribunal passed the order in August 2018 and in its award granted Karnataka a total of 13.42 tmcft (380 Mcum) of water of which 8.02 tmcft (227 Mcum) was for the proposed Mhadei Hydroelectric project, 1.5 tmcft (42 Mcum) for in basin use and irrigation and allowed the diversion of 1.72 tmcft (48 Mcum) of water from the Kalasa stream and 2.18 tmcft (61 Mcum) at the proposed Bandura dam. In all, the tribunal permitted Karnataka to divert 110 Mcum of water from the Mhadei basin to the east flowing into Malaprabha basin.  

Both the States have challenged the tribunal’s verdict before the Supreme Court.  

“Though the tribunal upheld Goa’s contention that the projects would jeopardise navigation in the Mandovi estuary, available information is sufficient to show that these projects have no impact on navigation in the Mandovi estuary or the Cumbarjua Canal. Indeed, navigation in the Mandovi, which is made possible by the tides, is possible even during the lean season, when the natural flow of the Mhadei is negligible,” the paper said.  

Demand explanation

Following this report, members of the Mhadei Movement, dressed in blue T-shirt, staged a protest outside the NIO complex near Goa’s Dona Paula, with placards displaying a red cross mark on the photographs of the scientists, shaming them, with words such as ‘BJP sold Mahadayi‘, ‘Mhadei deal by NIO’, ‘Anti-Goa NIO’… demanding an explanation from the hydrologists and the institutes for the reason behind publishing the report. 

Revolutionary Goans Party (RGP) president Manoj Parab said, “Why are the non-Goan scientists running research on this subject that does not concern them? We are questioning the timing of this report. We spoke to environmentalist Rajendra Kerkar who has done extensive research on Mhadei and he told us that the NIO scientists wrote the report sitting inside their air-conditioned office without having any ground understanding. The three scientists have manufactured this report to favour Karnataka which has gone ahead with the construction of dams on the river, despite the case being heard by the Supreme Court. This is a conspiracy by the BJP.”  

The party further demanded Goa Chief Minister Pramod Sawant and Congress leaders from the State to come out and speak on the matter and make their stand clear or are they too in favour of the report, Mr. Parab questioned.  

Viresh Mukesh Borkar, RGP’s MLA, said, “The report was published on September 11, 2024, quietly, and no one knew. It is surprising as the Chief Minister also did not say a word on this for so many months. This looks like a hidden agenda of the BJP government. When the case is already before the Supreme Court, publishing this report means the scientists want to favour the case of the Karnataka government. It is a known fact that Goa’s groundwater is depleting, and this river serves the people and flora and fauna of north Goa, if they block its flow from the Western Ghats, Goa will face a man-made disaster.”