After realising a record quantum of over 400 thousand million cubic feet (tmcft) of the Cauvery waters last one year, Tamil Nadu is in a paradoxical situation staring at an acute water shortage, especially in the delta region.
The Mettur dam, considered the mainstay for farmers in the central parts of the State, now has a storage of less than 16 tmcft against the capacity of 93.47 tmcft. This has forced the authorities not to open the dam on the scheduled date of June 12.
Considering that the State’s realisation exceeded the 400 tmcft for the first time since 1981-82, the question on many people’s mind is whether the State wasted the water and if it could have done anything to reduce the wastage. Around 130 tmcft of water, which is nearly one and a half times what the Mettur dam can hold, flowed into the sea, particularly during July-August period last year, through the Lower Anicut in Cuddalore district which is at the tail of the Cauvery system.
An explanation given by water managers is that Tamil Nadu, with its plain terrain downstream the Mettur dam, does not have scope for storing any huge quantum of water. Some check dams can be built but they would not be, in any way, a substitute for a massive reservoir.
As far as the year 2018-19 is concerned, the northeast monsoon did not yield much rainfall, forcing the authorities to depend only on the Mettur dam for irrigation requirements of the delta. As per a conservative estimate, about 330 tmc ft of water was drawn for irrigation, according to officials of the government, looking after issues concerning the Cauvery. A senior official explains that eventually, “no water goes waste” as this helps the water table to get recharged, benefiting 72,000 borewells in the region.
It is because of the release of water that the delta could achieve coverage of about 4.4 lakh hectares during the Samba cultivation season and around one lakh hectares for Thaladi. All this would help the State, a senior official of the Agriculture department says, to meet the target for foodgrain production (around 110 lakh tonnes), of which rice would account for 60-65 lakh tonnes.
Sand mining blamed
Notwithstanding these reasons, S. Ranganathan, veteran farmer from Mannargudi, says one of the important factors for the State not being able to utilise the water it received was the “mindless mining of sand” on water courses of the Cauvery basin in the State.
“The sill level of the water courses has, at several places, gone down at least by one-and-a-half feet. As a result, field channels are now at a higher level, leading to water going waste instead of reaching the designated farm fields,” he said and added that unless this situation was rectified at the earliest, the farmers would not stand to gain much even in the event of the State getting its share of Cauvery water.
P. R. Pandian, another farmer, said the idea of a dam at Rasimanal, upstream of Mettur, should be pursued. As per a proposal of the National Hydro Power Corporation (NHPC), a hydro power dam of 360 megawatt could be built there, with a capacity of 15.25 tmcft.
While a senior official of the Public Works Department says a project is under way to revamp the network in parts of Nagapattinam and Tiruvarur districts and forming part of the Vennar irrigation and drainage system, the Agriculture department’s official says the government is promoting the use of micro irrigation for raising pulses wherever possible in the delta.
