You are wrong. Tribunal's orders are also better weighed ones. You cannot justify equal sharing of water because the total extent of land cultivated in both the states vary enormously. For your information, Tamilnadu is the first state in India to have compulsory individual rain water harvesting in all households and establishments to fight drought(one of the appreciated moves of the then TN govt) and thatswhy the groundwater level has increased to good extent in recent years. Poor people were provided interest free loans to accomplish this task.
Even rain harvesting cannot prevent sudden flow of flood that too in monsoons.