Tale of transboundary river conflict: Understanding Kalasa-Banduri dam project

Goa and Karnataka are dependent on each other for their water needs. For the last few years, however, the states have been in a logjam over the sharing of water from Mahadayi river  

By Dimple Behal, Anuj Behal
Published: Thursday 03 September 2020
Mandovi river in Goa. Construction of Kalasa-Banduri canals over Mandovi river has been a point of contention between the Goa and Karnataka governments. Photo: Wikimedia Commons

India is on the brink of an acute water crisis, which has, to an extent, fabricated a looming threat of trans-boundary water conflicts. But a majority of the 276 trans-boundary watercourses worldwide lack an adequate legal and institutional cooperation framework, which hinders economic and social development, investments and regional integration.

The water disputes in India stem from a lack of a similar cooperation. The conflict on the Mandovi / Mahadayi river — flowing through Goa, Karnataka and Maharashtra — is one such example.

The Kalasa-Banduri Project undertaken by the Karnataka government proposes to divert Mandovi river water from Kalasa and Banduri canals into the Malaprabha river in the state to facilitate drinking water to 13 towns of Dharwad, Belagavi, Bagalkote and Gadag.

The entire project aims to construct a total of 11 dams on the river Mandovi. The diversion of water from Kalasa and Banduri nullahs, however, has been the point of contention between Karnataka and Goa, with the latter claiming it would strip the state of its flora and fauna.

The project

Goa and Karnataka are dependent on each other for their water needs. For the last few years, however, the states have been in a logjam over the sharing of water from the Mahadayi river.

The Kalasa-Banduri canal — part of the 11-dam project — aims to improve drinking water supply to the districts of Belagavi, Bagalkot, Dharwad and Gadag. It involves building across Kalasa and Banduri, two tributaries of the Mahadayi river, to initially divert 7.56 thousand million cubic feet (TMC) of water to the Malaprabha river, which supplies drinking water needs of the said four districts.

The project received clearance from the Centre in 2002. It, however, soon ran into trouble when the then Bharatiya Janata Party (BJP) government of Goa headed by Manohar Parrikar raised objections, claiming that the project would be an ecological disaster for the state.

The conflict

The Mandovi originates from Karnataka’s Belagaum district. The Mandovi river basin falls into the states of Goa, Karnataka and Maharashtra. The river is 81 kilometres (km) in length; 35 km of which flows in Karnataka, 1 km in Maharashtra and 45 km in Goa.

The seeds of the conflict were sowed over 40 years ago: In 1985Karnataka initially explored a 350 megawatt-hydro-electric project to divert 50 per cent of the Mandovi river water in Karnataka for irrigation.

The plan was also to allow a steady flow of water from the power project’s storage dam after using the water for irrigation purposes in Karnataka. This would have served drinking water and irrigation purposes in Goa as well.

State Area occupied by Mandovi River basin Proportion of drainage (in sq km) (in percentage)
Goa 43 1580 (78)
Karnataka 0.20 375 (18)
Maharashtra 0.025 77 (4)
Total drainage 2032 sq. Km 2032 (100)

Proportion of drainage in states. Table: Dimple Behal

Trouble started in 1993, when the Karnataka government submitted an environmental impact assessment (EIA) of the hydroelectric project. Goa claimed that the said EIA analysis “did not deal with the EIA of Goa as a result of the proposed project”. It suggested that “a separate EIA report with reference to Goa be prepared”.

In 1996, National Environmental Engineering Research Institute (NEERI) conducted a study on the feasibility of the project and an agreement was reached between the governments of Goa and Karnataka to build the Kalasa nala dam to drain 3.34 TMC from Kalasa nala to Malaprabha river.

Subject to the availability of 1.50 TMC of water needed for the Mandovi dam — proposed on the downstream of Kalasa nala for irrigation as well as drinking water requirements of Goa — both the governments consented to it.

Goa had to submit its own yield-based studies for diversion of 7.56 TMC in 2002, but did not disclose till 2006 any document with regard to the studies pursuant to the Central Water Commission’s request.

During the same time, Karnataka experienced a drought: It unilaterally went ahead and gave the so-called ‘in-principle’ inter-state clearance of water availability to Karnataka to divert 7.56 TMC of Mandovi water through Kalsa-Banduri nala projects to Malaprabha sub-basin in the non-forest area.

The Karnataka government claimed a state could unilaterally build a project on the inter-state river if there was no agreement or tribunal decision prohibiting such construction. 

It was then that the Ministry of Environment and Forests (MoEF) stepped in, claiming that the project required both environmental and forest clearances and advised Karnataka to re-submit proposals for necessary statutory clearances. It asked the state government to not pursue any work without obtaining the same.

The state of Karnataka, however, did not take any environmental clearance / permissions and carried out the project in violation of the Forest (Conservation) Act, 1980, and Section 29 of Wildlife Act, 1972.

Goa requested Ministry of Water Resources (MoWR) to take immediate steps to withdraw the so-called “in-principle” permission or to keep it in suspension till an agreement could be reached between the basin states, or referr it to a tribunal.

In 2006 itself, Goa took the case to the Supreme Court requesting that an interlocutory application to halt all construction activities over the river be issued under Section 3 of Inter State River disputes Act, 1956.

In order to fulfil the drinking water needs of the twin cities of Hubali-Dharwad and the nearby towns and villages, Karnataka decided to divert a meagre 7.56 TMC of its Mahadayi basin to the Malaprabha dam.

The tribunal action

The Mahadayi Water Dispute Tribunal was set up in 2010 to look into the issue. In 2018, it allowed Karnataka to divert 3.45 TMC to the Malaprabha dam instead of 7.56 TMC as initially decided.

Karnataka was allowed to withdraw 1.18 TMC from the Kalasa nala and 2.27 TMC from the Banduri nala from their original 3.56 and 4 TMC claims respectively.


Location of the Kalasa-Banduri canal. Source: Water Resources Information System. Markings by: Dimple Behal

But the standoff between the two states existed till as long as 2019. The MoEF in 2019 said the project did not need any environment clearance for it sought to serve drinking needs. But the same was not acceptable to Goa.

What was the basis the Union ministry concluded the project was solely a drinking water project? It is not known so far.

Impact on river basin

According to the Goa government, the Kalasa-Banduri water diversion scheme would submerge about 700 hectares of forest.

If Karnataka were to go ahead with the hydroelectric and diversion project — part of the 11 dams to be constructed under the diversion scheme — 2,145 hectares of forest area and 330 hectares of forest land for roads, dams, power houses, township, field offices, etc would be submerged. Some villages would also suffer the same fate.  

The project would submerge about 3,000 hectares in Karnataka — most of which is thick-forested area. The forest cover of Belgaum district would be reduced to eight per cent from 13 per cent, after releasing the forest land to Mahadayi diversion and the hydroelectric project, the state claimed.

Western Ghats is a mega biodiversity hotspot, the major portion of which is declared as a Protected Area. The whole of Western Ghats provide contiguous corridor for safe movement of wildlife in Goa.

If any water from Mahadayi is diverted by Karnataka, the flow of macro nutrients would stop, affecting the diverse flora and fauna in the low-lying area of Mahadayi Wildlife Sanctuary.

Goa maintained that the proposed diversion of water would lead to an increase in the tidal base water. This would affect the residents living on the banks of Surla river on account of depletion of river water.

The source of underground water would also be completely depleted. Goa, as a lower riparian state, has repeatdely pleaded to the Supreme Court and the tribunal that any plans to divert the said waters would not be practicable, as the same would cause irreparable damage to the water security of the state.

The project would also end in a complete ecological disaster wherein flora, fauna, hills, ghats, plains and predominant marine life, including mangroves and other species would be destroyed, the state pleaded.

The actions and attempts on the part of Karnataka would result in taking away livelihood as right of ecology and environment, which is a facet of Article 21 of the Constitution of India, Goa had pleaded.

Goa is one of the most prosperous states in India: It pays the highest per capita tax, earns the highest per capita foreign exchange along with mining, tourism, corporate taxes, income tax, excise etc. whose net worth amounts to Rs 8,000 crore per annum.

Inland water ways are among the lifeline of the state and any attempt to reduce the flow of Mahadayi river, even to a minuscule extent, would cause the navigational traffic in the inland water ways. Mining and export of mineral ore and tourism are the backbone of the Goan economy and contribute substantially to the national gross domestic product (GDP).

A 509 square kilometres-stretch of the river in Goa is environmentally fragile, primarily on account of the factors relating to high salinity and the eco-systems that develop with such salinity features.  

The stretch is used to get to Panaji and Marmugao ports. The salt water ingress and tidal influence is almost 36 km upstream beyond Ganjem; this corresponds to almost 69 per cent of the river’s length within Goa.

Thus, it maintained that any alteration of the river would result in drastic reduction of fresh water flow.

The diversion would also impact agricultural activities. The Mahadayi is a perennial source of sweet water and runs about 76 km within Goa. Around 46 km of it up to Ganjem is saline, which leaves only 30 km of fresh water spanning seven potential agriculture talukas in Goa in the Mahadayi basin.

Goa has pointed that the project, with the 11 dams in an area of 50 km radius, has been planned in an area much prone to earthquakes. The two large dams under the project — Supa reservoir and Codasalli — are only 50 and 35 km away from the Mahadayi project area.


The impacts of such development projects are adverse, especially when it comes to natural resources and the need to share them between different states / territories. Trans-boundary water agreements must be sufficiently robust to address rising environmental and climatic factors as well as changes in society and population.

Nearly half the population is served by cross-border water, and proper planning, growth and management is essential to meet the current and future water needs and to respond to a possible water shortage. 

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