There is no definitive answer to your question. Some power plants can produce several kilowatt hours of electricity per ton of water, and some power plants can only produce one kilowatt hour of electricity with hundreds of tons of water.
The energy production capacity of a ton of water in a hydroelectric plant is linked to the difference in height. When water reaches a low point from a high point, the potential energy of the water's position decreases with height. law of conservation of energy, the reduced potential energy becomes electrical energy. The quantity of electricity produced is directly proportional to the quantity of water and the height difference. Assuming that the height difference used by the hydroelectric plant is 100 meters, in theory, 3.67 tons of water can produce one kilowatt hour of electricity. energy losses (loss of water transport channels, converter lossession of generators and turbines). The loss is about 20%, so about 100 meters of height requires 4.6 tons of water to produce one kilowatt hour of electricity. Different heights can be calculated proportionally. Greater height will require less water.