The diagram presents the process of creation of electricity in a hydroelectric power place.
Overall, the main process involves the water from the river. The intake of water is only in the daytime, at night all the water flows back and the dam gets closed and stops the water from coming.
The first step in the process of generation of electricity is the water from the river, it jumps into the high-level reservoir. It stays there at night to increase its capacity after the dam opens during the day-time, the water flows down the tube to generate electricity after it gets to the reversible turbines which then spin it and the water gets into the low-level reservoir, then the generator receives the energy from the reversible turbines and power lines and transfers into the national grid.
Night time is completely the opposite, during the night the water from the low-level reservoir pumps back into the reversible turbines and flows back up the tube to the dam, after it closes via the dam and all the water stays in the high-level reservoir.