Lesson: India can learn from US on Water sharing

Indian southern states (Tamilnadu, Karnataka, Andhra & Kerala) has been fighting for almost decades on water sharing between them like cauvery issue, periyar dam issue, krishna water issues etc.,. So how does US handles such issue in its Western states?The Federal Govt.  in US reach a pact with the states on how to allocate water if the river runs short.For example, The Colorado River pact outlines how much water the seven states served by the Colorado river — California, Nevada, Arizona, Colorado, Utah, New Mexico and Wyoming — would receive annually.
So what's the problem in India? In India the State Govts. reach river pacts within them which they don't abide by and the central Govt. remain a mere spectator whenever a conflict arises.
In US, they reach to the pact by taking the best of several proposals by the states, environmental organizations and others and giving emphasize importance to all seven states to agree with the result.
So India has to nationalize its rivers first and reach to an pact with the states sharing water.Otherwise the individual states may become more and more greedy and this may well develop into a huge national issue in future.