Every third or the fourth year, river Cauvery, the lifeline of both Karnataka and Tamil Nadu, embitters the harmonious relationship existing between the two southern states. The Cauvery river dispute is more than a century old but a lasting solution is eluding.
Out of the riparian states of Karnataka, Tamil Nadu, Kerala and the Union Territory of Puducherry, the first two are major players. When the river supplies are copious, there is obviously no dispute. It is only when the river supplies are low that the two states literally go to war. One can examine some basic facts about the river, its water potential, the Cauvery Water Disputes Tribunal’s (CWDT) award and measures that could be taken to minimise or mitigate the distress in the bad years.
General: About 42% of the Cauvery basin area lies in Karnataka, 54% in TN and the rest 4% in Kerala and Puducherry. In a normal year, the contribution of Karnataka and TN to the river system is 53% and 30%, respectively. In an average year, the total flow in the river is 730 TMCft (Thousand Million Cubic Feet).The CWDT allocated in 2007 a quantity of 270 TMCft (37%) to Karnataka, 419 TMcft (54%) to TN and the remaining 66 TMCft (9%) to Kerala and Puducherry.
Karnataka felt aggrieved that though its contribution to the river flows was much higher than that of TN, its allocation was less than what it should get. The Tribunal also stipulated that Karnataka should release annually 192 TMCft to TN as per the monthly schedule drawn by it. It did not spell out clearly what should be the quantum of releases in bad years. There exist four major dams in Karnataka –Krishna Raja Sagar, Kabini, Harangi and Hemavathi - with an aggregate gross storage capacity of 114.37 TMCft. Tamil Nadu has three big dams - Mettur, Bhavanisagar and Periyar - with an aggregate storage capacity of 136.54 TMCft.
Demand: The reservoirs on the Cauvery river and its tributaries are designed to meet the irrigation needs of all the four states, generate some hydro power and meet the drinking water requirements of Bengaluru, Mysuru and many other smaller towns and villages. The farmers in TN and Karnataka grow principally rice and sugar cane. These are water-intensive crops. The area between Mandya and Srirangapatna is a sugar belt. Lush green paddy fields on either side of the National Highway between Bengaluru and Mysuru greet the visitor. Tamil Nadu raises three rice crops in a year.
I suggest some measures which, if implemented, would ensure lowering of water demand and also making the riparian states less dependent on the river supplies.
(1) Crop Pattern: Both Karnataka and TN at present grow water-guzzling crops like sugar cane and rice. Sugar cane is a perennial crop, which requires 3,000 mm of water all through the year. Rice requires 1,200-1,500 mm of water. In drier years, it becomes extremely difficult to meet the huge demand of both the states. The solution that suggests itself is to curtail the demand by way of replacing high water-intensive crops by light crops. Millets, oilseeds, pulses, ragi etc should replace sugar cane and rice cultivation. Unfortunately, India has still not developed a reliable weather forecasting system.
If there were such a reliable system, the farmers would have a choice at the beginning of the sowing season itself to sow the particular type of crop depending upon the supply position. Till such time a reliable forecasting system is developed, it would be a gamble to grow water-intensive crops. The farmers should be educated about the wisdom in going in for light crops. The field workers of the agricultural department should do this. The TN government should dissuade its farmers from raising more than one rice crop.
(2) Water-saving measures: Many farmers are under the mistaken impression that “more is better”. Application of more water affects the yield, spoils health of the soil and also results in wastage of precious water. Water should be applied by drip/sprinkler irrigation. Irrigation water should be charged on volumetric basis. The water conveyance system, right up to the field level, should be lined to minimise transmission losses.
(3) Conjunctive use: The subsoil water levels in irrigated areas are always high. Bore/dug wells should be provided in the irrigated areas so that underground water supplements the canal supplies. This would lessen dependence on irrigation water, help prevent water logging and the consequent deterioration in the health of the soil.
(4) Drinking Water issues: Bengaluru, Mysuru and other small towns, having a total population of 13 million, depend on Cauvery water. The requirement in a full year is as much as 23 TMCft. There is what is called ‘water illiteracy’ among the users. A campaign should be launched to educate the users to conserve water. A good amount of water is lost due to the leakages in the distribution system. The Bengaluru Water Supply and Sewerage Board as also other municipalities should plug the leakages and replace the old and rusted pipelines.
Unauthorised pipe connections should be detected and penal action taken against the offenders. Rain water harvesting (RWH) should be made mandatory so that precious rainwater is not allowed to flow to the gutters. Determined efforts should be made to raise the depleting water table levels by recharging with RWH. Installation of sewage water treatment plants should be made mandatory. A number of lakes have vanished in the city, thanks to the real estate lobby. These lakes should be revived which will help ease the water problem to some extent.
A national policy to deal with inter-state river disputes should be drawn. The Centre should lay down broad principles for sharing water amongst the riparian states in years of distress.
(The writer is former Chief Engineer, and Irrigation and Command Area Development Commissioner, Govt of Gujarat)