Reduced quantum may sound death knell for kuruvai: Experts

According to P Kalaivanan, the Cauvery irrigation district comprised of 12 districts need 240 tmc for kuruvai and at least 200 tmc for samba, as the poor efficiency of irrigation channels would mean that only 60 per cent of water would be realised at the farm level. 

Thus, the five lakh acre cultivation of kuruvai  has shrunk into 1.5 lakh acre, while samba cultivation has fallen to 12 lakh acre from 16 lakh acre. In the verdict, the court held that the groundwater potential in the delta to be 20 tmc, but Kalaivanan pointed out that the water level fluctuated from one region to another. 

For instance, in the combined Thanjavur district (Nagapattinam, Tiruvarur and Thanjavur), only Cauvery basin has the  potential of 20 tmc whereas it is not possible in the other basins like Vennaru and Grand Anaicut. 

“Even the Cauvery basin have that much groundwater only when the monsoon is strong,” Kalaivanan said. In places like Needamangalam and Valaigaiman in Vennaru basin where the soil is clay, the water cannot be used.

With no rainfall in June, July and August, the filter points have dried and the groundwater level went too low this year. So groundwater potential would vary based on the monsoon, which should be factored in the water-sharing arrangement, he said. 

However, another expert V Palaniappan noted that 160 tmc water was available from rains, which could be stored by creating farm ponds, and also desilting lakes and irrigation canals. 

“The government should equip the waterbodies based on the forecast, which should be done prior to monsoon so that the water can be stored for future use,” he said.