A combination of factors has led to “huge groundwater extraction” over and above the replenishable capacity of the aquifer in the Cauvery delta, experts say.
Arguing against the Supreme Court’s decision to reduce the quantum of Cauvery water allocated to Tamil Nadu on the grounds that 10 tmc ft water was already available to the State, P.M. Natarajan, former director of the Centre for Climate Change at the Periyar Maniammai University, says the geological formation of the Cauvery and the Vennar basins, with thick clay at the top, is not allowing rainwater to percolate into the aquifer. Parts of the delta region, which bore the brunt of the 2004 tsunami, are yet to see the restoration of the original character of their soil after suffering from salinity.
He contends that Karnataka’s failure in sticking to timely release of water has not only led to a reduction in the crop area in the Cauvery delta but has also resulted in the absence of recharge and return flow of the ground and surface water resources.
Due to these factors, the groundwater potential of the Cauvery delta is likely to reduce in the future. Also, the quality of groundwater will change to an “unacceptable standard,” Dr. Natarajan points out.
‘Divert from Moyar’
To address the problem of the reduction in Tamil Nadu’s share of Cauvery water, S. Ranganathan, general secretary of the Cauvery Delta Farmers’ Welfare Association, suggests that water to the extent of 14.75 tmc ft be diverted from the Moyar river in The Nilgiris district to Bhavanisagar, so that the delta farmers are not made to suffer. According to him, Moyar, a tributary of Kabini, accounts for 50% of the contribution to the Kabini reservoir.
He wants the State government to impress upon the Centre the need to constitute the Cauvery Management Board at the earliest, so that farming operations during the short-term kuruvai cultivation season are not affected.
