Hydropower engineering is the science of how flowing water is used to generate electricity. Structures such as dams and water diversion channels are typically designed on the principles of how water flows from high elevations to low lying areas. Hydropower systems are also designed around knowledge of the hydrologic cycle. Ocean water evaporates from the heat of the sun, weather patterns create clouds which drop rain over landscapes, and water runs along rivers back to the sea. River elevations, prevailing weather patterns, and knowledge of how to convert running water to electricity are generally essential to understanding hydropower engineering.
Water wheels have been used for many years on farms, to move water and process grains. Hydropower engineering for power generation typically involves using water to drive turbines. The energy of the water is converted to a form that can be used by generators to make electricity. A common way to do this is to build a damn, which is an example of how engineers have adapted technology to geology and water flow. Water is held back and can be released through tunnels or channels; it is then passed through a turbine before exiting the man-made path and continuing along the river.
Hydropower engineers can also build a barrier, which directs water to a building it can flow through to produce power. A power generating station can also be built along a diversion channel. The river water is blocked by a man-made barrier along its original width. Engineers have also designed multiple dams and barriers along a river to create a multi-stage system. In coastal areas with high tides, it is often possible to place turbines in the path of the flowing tide to generate power.
To design the appropriate system, hydropower engineering generally requires mathematical calculations. These often account for the slope of the land, speed of the water, and how the water is expected to flow at certain times of the year. Minimum and average potential power is derived from the water flow, to evaluate the potential for using a particular site for hydropower.
In countries with mountainous terrain, hydropower engineering is often taught at universities. The development of hydropower systems is significant where energy shortages are possible. Large businesses that employ hydropower engineers can specialize in constructing specific hydrologic structures. Sometimes they also provide services for assessing sites, building various types of turbines, and managing different phases of construction.