M Raghuram | Aug 30, 2018 | 5 min read
Mysuru: It is to be admired how Tamil Nadu has managed water received from Karnataka’s Cauvery river. After the recent rainfall that devastated the Kodagu district of Karnataka, Tamil Nadu received copious amounts of water released from the Krishnaraja sagar and Mullaperiyar dams. This filled up Tamil Nadu’s Mettur dam twice over the regular level, within the last fortnight.
Tamil Nadu, however, did not have any large-scale flooding like in Kerala or Kodagu. This is thanks to the massive network of canals that divert water towards lakes, ponds, tanks and reservoirs. When filled, every canal becomes a reservoir, some lined with cement, and others unlined. This network of canals is the state’s central nervous system, driving their agriculture, and even directing domestic water into towns, enroute the reservoirs.
Though it is difficult to ascertain if the network of canals was designed solely to be a flood control mechanism, a senior official of the Tamil Nadu water resources department says the chief objective was to provide connectivity to the 84 dams in Tamil Nadu. "These dams are distributed across four divisions - Chennai, Madurai, Trichy and Pollachi, many of which are interconnected," he says.
Canals support crops as well
“Many lakes, ponds and tanks get their water from these canals. There are mechanisms that hold water in the form of mini check dams, which helps prevent flooding, and works as a flood control measure,” the official adds.
The Buckingham canal is one of the largest in the
country, running between Kakinada in Andhra Pradesh and Villupuram in Tamil Nadu for a total of 796 km, of which 316 km flows through Tamil Nadu.
According to sources at the Tamil Nadu Water Resources Department, the Bhavani basin’s canals are spread across 1,01,589 hectares, while the lower Bhavani project canals cover 83,505 hectares.
“Over the last fortnight, Tamil Nadu has received not less than an average of 45,000 cusecs of water per day from the Cauvery, and similar volume of water from the Mullaperiyar dam. Tamil Nadu’s lower riparian area should have been flooded twice over, but due to the canal system around the Cauvery and the Bhavani basin, it did not,” say Tamil Nadu Vivasayigal Sangam (Federation of Tamil Nadu Farmer’s Association) activists.
Tamil Nadu Water Resources Department officials agree that the intricate canal system has helped not just flood control, but facilitated easy inter-basin transfer of water for crop management. "We may have water disputes with Karnataka and Kerala, but inside Tamil Nadu, the canals have given us the power of equitable water distribution and crop management,” a deputy director of the department told Firstpost under conditions of anonymity.
This model in Tamil Nadu has not inspired Karnataka yet. Canals built in 1960s like Varuna and Vishweshwaraiah, still provide water only to approximately 11 lakh hectares in the old Mysore region. Most of the water augmented from Krishnarajasagar dam is used for just domestic purposes in the city of Bengaluru.
'All rivers in Karnataka need attention'
R. Sridhar, an independent expert on the Cauvery says, “During times like these where rains have created havoc in Kerala and Kodagu, only the augmented water facilities have played their part, serving as the partial cause of the large-scale destruction. The Karnataka government should have taken steps to build canals, so that excess water could have been channelized to different parts of the state, connecting the reservoirs. This would have circumvented the need of opening up the reservoirs all at once.”
According to experts, two perspectives have been put forward to distribute and control water resources.
The Krishnaraja Sagar reservoir built across the Cauvery, in Karnataka’s Mandya district, has an FLR (Full Reservoir Level) of 121.80 feet. In the event of excess rain, as seen over the last fortnight, the reservoir could have channelized the water towards Mandya and Ramanagaram districts, which would have sustained crops like paddy and millets. This mechanism would have also served small towns along Bangalore-Mysore state highway 212, observes the Cauvery Horata Samithi.
Madhu Made Gowda, a leader of the Cauvery Hitarakshna Samithi, thinks that disputes between the two states would have been resolved had Karnataka released 10,000 cusecs of water to Tamil Nadu every year, as directed by the Supreme Court.
Farmers have appealed to the Karnataka government to build additional canals without jeopardising the pact with Tamil Nadu. “But it is not just Cauvery, we will have to look at rivers Kabini, Krishna, Godavari, Sharavati, Varada, Ghataprabha and many others in the state. These are the rivers that get good water inflow during the monsoons," says Gowda.
About the management of Cauvery water, Gowda says, "The Cauvery Monitoring Committee (CMC) had not presented the case of Karnataka to the judicial officers of the Supreme Court. The CMC should send a delegation to research and identify the inflow and outflow, and come to a realistic estimation of water needed for agriculture, drinking and domestic uses,” says Gowda.
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