I will add to this section as needed, but I will start off with the most common units of measure for lakes and rivers.

General terms for the flow and volume of water

CFS refers to flow; AF refers to volume

CFS (Cubic Feet per Second) is a rate of water flow which will supply one cubic foot of water in one second. A cubic foot of water is equal to 7.48 US gallons of water. Thus, water flowing at 1 cubic foot per second is moving 448.8 gallons per minute.

AF (Acre Foot) is a unit of volume equal to one acre of water, one foot deep. An Acre Foot of water is about 326,000 gallons.

According to the Water Education Foundation, an average California household uses between one-half and one acre-foot of water per year.


Terms related to the generation of hydroelectric power

The following definitions of terms was taken from the glossary of hydropower terms at the website. Please note that terms are arranged in logical rather than alphabetical order.

Hydropower: The harnessing of flowing water—using a dam or other type of diversion structure—to create energy that can be captured via a turbine to generate electricity.

Power house: The structure that houses generators and turbines

Penstock: A closed conduit or pipe for conducting water to the powerhouse.

Turbine: A machine that produces continuous power in which a wheel or rotor revolves by a fast-moving flow of water.

Scroll case: A spiral-shaped steel intake guiding the flow into the wicket gates located just prior to the turbine.

Wicket gates: Adjustable elements that control the flow of water to the turbine.just prior to the turbine.

Runner: The rotating part of the turbine that converts the energy of falling water into mechanical energy.

Generator: Device that converts the rotational energy from a turbine to electrical energy.

Transformer: Device that takes power from the generator and converts it to higher-voltage current.

Tailrace: The channel that carries water away from a dam.

Pumped storage: A type of hydropower that works like a battery, pumping water from a lower reservoir to an upper reservoir for storage and later generation.

Head: Vertical change in elevation, expressed in feet or meters, between the head (reservoir) water level and the tailwater (downstream) level.