The diagram shows how electricity is generated in a hydroelectric power station Summarise the information and reporting the main features and make comparisons where relevant

The diagram illustrates the mechanism of a hydroelectric power plant. It can be seen from the pictures that the process involves three main stages.
The first phase starts when water flows from the river to a reservoir. This artificial lake is surrounded by a dam and is called a high-level reservoir. The water flow is narrowed down to the gates under the barrier to create smaller and stronger streams. These gates are opened during the daytime and closed at night.
Through the gates, water runs to the low-level reservoir, which, like its name, locates at a much lower elevation. Before entering the pond, water passes through the power station, rotates the turbines, and activates the generator. Electricity is generated and then transferred to the national grid via a system of power lines.
The third part of the process occurs at night when electricity demand gets low. Engineers reverse the turbines and pump water back into the high-level reservoir. Additional water fills up the lake to prepare for the generation cycle the next day.