The water sharing scheme was setup for a reason. All parties need to live up to this. Karnataka is the one which has never lived up to this so they need to change.
Few years back, there were calls to stop providing electricity to Karnataka from Tamil Nadu. Luckily, the politicians in TN were more mature than that to stop electricity. Karnataka should think about the consequence of stopping resources like water unless someone retaliates with electricity.
These southern states only think about themselves and there lies the problem.