Panaji, Aug 12 (IANS): Goa loses nearly 40 percent of its rainwater due to natural discharge, a study of the state's groundwater resources has revealed.

The study by the state's department of water resources and Bangalore-based Central Groundwater Board, however, said there was no decline in Goa's ground water reserves in the last two years but it remained mum on the effects of open cast mining damaging huge underground water reserves in the hinterland.

The state is one of the top rainfall garnering states in the country with an average of 3,005 mm annually, third after Karnataka and Kerala.

"The loss due to natural discharge is 40 percent as against the recommended figure of 5 percent in Goa," stated the report titled 'Dynamic Groundwater Resources of Goa', released earlier this week.

"The net groundwater availability is 132.74 million cubic metres and the state figure for groundwater development is only 33 percent, indicating enormous opportunity for future development," it added.

"The aquifers here are porous. Most of the rainwater finds its way into river bodies. The natural discharge is as high as 40 percent," chief engineer in the state water resources department S.T. Nadkarni told IANS.

He said there was "no question" of decline in Goa's groundwater reserves.

But industrial hubs at Verna and Kundaim, both located 25 km from Panaji, and the coastal tourism belt, which hosts 26 lakh tourists annually, were emerging as 'stressed' areas as far as groundwater was concerned, he added.

"The water consumption of these areas is high because of the high density of population, industries and commercial establishments. We are trying to recharge the groundwater in such areas," Nadkarni said.

The official, however, said the effect of iron, manganese and bauxite mining in Goa's hinterland on the groundwater resources there had not been specifically studied by the report.

Civil society activists campaigning against illegal mining often complained that the open cast mining pits drilled into the earth for extraction of ore ran through and dried hundreds of underground aquifers whose water once mixed with mining rejects took the form of mining sludge that found its way into the rivers.