PANAJI | March 08, 2017: The proposed diversion of Mhadei (Mandovi) river will hit sand mining in Goa, experts have warned.

Speaking to ‘The Navhind Times’ on Tuesday, they said that reduction in water flow due to the proposed diversion of a large quantum of water of the Mhadei and its tributaries would severely affect formation of sand.

It will adversely affect livelihood of hundreds of Goans involved in the activity of excavation and diminish supply of a naturally available construction material.

The repercussions would be in degradation of rivers as excavators would be forced to dig deeper into riverbeds. It would result in ecological damage and harm interests of future generations of Goans, geologists have cautioned.

Maximum impact of the water diversion on sand mining will be felt in the Mhadei basin where the government has issued highest number of permits for extraction.

Of the 441 permits issued, over 53 per cent are in the Mandovi basin.

The geologists explained that sand formation in two important rivers – Mandovi and Chapora – has already come down over the years after the construction of upstream dams – Tillari and Anjunem. Future formation would decrease drastically as water volume would reduce after the diversion.

Moreover, the Karnataka government have planned hydroelectric projects on the Mhadei. “No flow of water means no more sand,” said officials in the department of mines and geology, explaining that sand is generated through erosion of solid material. In rivers, it is generated through abrasion between boulders in the waterbed. While on land it is through wind weathering.

Manuel Barreto, deputy director, department of mines, said, “The exact impact can only be ascertained after a proper study.”

Sand mining in Goa is permitted in a cluster of seven rivers – Chapora, Mandovi, Terekhol, Macazana, Rivona, Loutolim and Talaulim. The rivers are indirectly fed by the Mandovi although two of them –Chapora and Terekhol – originate in Maharashtra.

Legal sand mining in Goa has resumed after a long hiatus.

A committee with representatives from the department of mines, the Captain of Ports, the water resource department, the Goa State Pollution Control Board was constituted to determine sand deposits in the rivers and extraction sites.

The experts said the scientific assessment of sand deposits by the committee is going to be useless if the rivers dry up and lack the vigour to generate sand. They said that sand is not rejuvenated naturally. It needs constant erosion. Sand is also generated by floods but with no incidents of floods, Goan rivers can only have sand in them through the process of erosion.

(Source: http://www.navhindtimes.in/)