The Mhadei river, which originates in Karnataka and is called the Mandovi in Goa, traverses 28.8 km in Karnataka and 81.2 km in Goa. The river, known as Goa's lifeline, has a 2,032 sq km catchment area in Karnataka and 1,580 sq km in Goa.
The Mhadei valley has 700 sq km of pristine forest, which hitherto was left out of the timber mafia's clutches. The decade-long controversy gained momentum last year when Karnataka began working on the Kalsa and Banduri Nullah dam projects on the border with Goa, damming 7.5 tmc of water.
The original scheme involves constructing seven dams that will divert 255 million cubic litres of water from the Mhadei to Malaprabha basin, which Karnataka wants to use for irrigation and drinking purposes.
"Mhadei is our survival. Of the 11 Talukas, the river wades through six, covering 12 villages and cultivable land of 91,072 hectares. Of the 11 rivers in Goa, the Mandovi is the biggest, providing maximum potable water.
"Goa is a water-deficient state. As against the projected requirement of 2,674 m cum by 2051, the actual water available in the basin for conservation and utilisation is only 1,531 m cum.
"This includes 75 per cent of dependable water generated in the upper reaches of the basin in Karnataka and Maharashtra and the foothills of Goa," he said. "It comprised six frontier forests - remnants of primeval natural forests that have remained relatively undisturbed and big enough to maintain biological diversity.
Citing the wildlife heritage in the forest around the dam sites, the area constituted an endemic bird area as per international birdlife, Cambridge and a level-I tiger conservation unit of the world wide fund for nature.
"Also it is declared as one of the world's 12 ecological hotspots as part of the Western Ghat by the Rio Earth Summit 1992.