Short answer: Because “whiskey’s for drinking, but water’s for fighting over”.
|Tufa tower of Mono Lake|
Nowhere on earth the decline of groundwater is faster than it is in northern India. It became evident when twin satellites from NASA’s Gravity Recovery and Climate Experiment (GRACE) detected the ground water storage based on gravity. India had it’s share of disputes over the sharing of river waters with Bangladesh and Pakistan. But the main war for water in India is happening in the south.
The final judgement by the Tribunal was delivered in 2007 as per ISRWD. It allocated 419 TCM ft. of water annually to Tamil Nadu, 270 TCM ft. to Karnataka, 30 TCM ft. to Kerala and 7 TCM ft. to Puducherry. None of the states were happy with the decision and review petitions were filed by them for re-negotiation. With no side willing to back off, the dispute still remains nine years since the judgement.
Experts did some complicated maths (which has lot’s of assumption) to come up with the magic number of 740 TCM ft of total water available from Kaveri Basin (if monsoon does not fail). Of that the major chunk of 462 TCM ft is the yield of the river in Karnataka. Karnataka can keep only 270 TCM ft and give the rest (192 TCM ft) to TN. TN also generates 227 TCM ft from it’s own catchment area increasing the total share of the state to 419 TCM ft (227+192). Kerala, which generates 51 TCM ft, can keep only 30 TCM ft. The rest 21 is divided between Pondicherry (7 TCM ft) and environmental purposes (14 TCM ft).
The upper-riparian nations (riparian nations—nations across which, or along which, a river flows) initially base their claims on absolute territorial sovereignty, typically claiming the right to do whatever they choose with the water regardless of its effect on other riparian nations. Downstream nations, on the other hand, generally begin with a claim to the absolute integrity of the river, claiming that upper-riparian nations can do nothing that affects the quantity or quality of water that flows in the watercourse. The utter incompatibility of such claims guarantees that neither claim will prevail in the end, although the process of negotiating or otherwise arriving at a solution might require decades.
The 2016 water crisis started when Supreme Court (SC) directed Karnataka to release 15,000 causecs of water to TN for 10 days on 5th September. This order was passed to satisfy the demands of TN's farmers for growing summer crops. This led to violent protests in Karnataka, as the water flow was already less. As the law and order went out of control SC revised the orders this Monday (12th Sep). Now Karnataka has to provide 12,000 causecs instead of 15,000. The duration, however, was increased till 20th September instead of 15,000 causecs for five days as Karnataka wished, and the protest continues.