Glossary
- A -
Acre-foot - The volume of water that would cover one acre, one foot deep.
Active Capacity - The reservoir capacity normally usable for storage and regulation of reservoir inflows to meet established reservoir operating requirements. Active capacity extends from the highest of the top of exclusive flood control capacity, the top of joint use capacity, or the top of active conservation capacity to the top of inactive capacity. It is the total capacity less the sum of the inactive and dead capacities.
Apportion - To divide and assign according to a definite rule. The division is not necessarily equal but is fair according to the respective interests of the parties involved.
Archaeology - Scientific studies of historic peoples through their artifacts, skeletal remains, fossils and objects of human workmanship.
Attenuate - To lessen the amount, force, magnitude, or value of.
- B -
Backwater - A small, generally shallow body of water attached to the main channel, with little or no current of its own.
Base load - The minimum constant amount of load connected to the power system over a given time period, usually on a monthly, seasonal, or yearly basis.
- D -
Depredation - The act of killing, damaging or consuming animals, crops or other agricultural resources.
Detritus - A mass of decomposing organic compounds.
Drought - Droughts are temporary abnormalities determined by deficient precipitation and depend on the area in question. In one area of the world a drought may be a week without rain, while in drier parts of world like the American Southwest, it might be an annual rainfall deficit of less than four inches.
- E -
Ecosystem - The complex of a community of organisms and its environment functioning as an ecological unit.
Endangered Species - According to section 3 of the Endangered Species Act of 1973, any species which is "in danger of extinction throughout all or a significant portion of its range."
Environmental Impact Statement (EIS) - A NEPA compliance document used to evaluate a range of alternatives when solving the problem would have a significant effect on the human environment. The EIS is more than a document, it is a formal analysis process which mandates public comment periods. An EIS covers purpose and need, alternatives, existing conditions, environmental consequences, and consultation and coordination.
Extinction - No longer in existence.
Extirpated - A wildlife species that no longer exists.
- F -
Fauna - The animal life in a particular region or period.
Fishery - The aquatic region in which a certain species of fish lives.
- H -
Habitat - The place or environment where a plant or animal naturally or normally lives and grows.
Hydroelectric Power - Electrical energy produced by flowing water.
Hydrologic Cycle - The sequence of conditions through which water passes from vapor in the atmosphere through precipitation upon land or water surfaces and ultimately back into the atmosphere as a result of evaporation and transpiration.
Hydrology - Science dealing with the properties, distribution, and circulation of water on and below the earth's surface and in the atmosphere.
Hypotheses - offer a proposed explanation for a phenomenon. Scientific hypotheses must be testable and based on previous observations or extensions of scientific theories.
- M -
Mitigate - To lessen or to try to lessen the seriousness or extent of.
- N -
National Environmental Policy Act (NEPA) -An act requiring analysis, public comment, and reporting for environmental impacts of Federal actions. See National Environmental Policy Act of 1969.
National Register of Historic Places - A federally maintained register of districts sites, buildings, structures, architecture, archaeology, and culture.
- O -
Omnivorous - An organism that eats both plant and animal matter.
- P -
Peaking Power - Power generated in a short response time to satisfy higher electrical demands that occur typically during daytime hours and in the summer months.
Penstock - A pipeline used to convey water under pressure to the turbines of a hydroelectric plant.
Predation - Hunting and killing another animal for food.
Predator - An animal that lives by killing and eating other animals.
- R -
Ramp Rate - The rate of change in instantaneous output from a powerplant. Changes in ramp rate are often implemented to protect habitat and the public from undesirable effects caused by large, sudden changes in riverflows.
Refugium - An isolated area where extensive changes, typically due to changing climate or by disturbances such as those caused by humans, have not occurred and where plants and animals typical of a region may survive.
Rejuvenation - To restore to an original or new state.
Riparian - Relating to or living or located on the bank of a natural watercourse (as a river) or sometimes of a lake or a tidewater.
Riverine - Relating to, formed by, or resembling a river.
- S -
Salinity - The concentration of mineral salts dissolved in water.
Selective Withdrawal Structure - A temperature control device that allows dam operators the flexibility to draw water from different depths of the reservoir to modify the temperature of the water discharged downstream.
Seven Basin States - The states of Wyoming, Colorado, Utah, New Mexico, Arizona, California, and Nevada, each with an interest in the Colorado River.
Spawn - The act of reproduction of fishes.
Subterminal - Situated or occurring near but not precisely at an end.
- T -
Threatened Species - Any species that is likely to become an endangered species within the foreseeable future throughout all or a significant portion of its range.
Total Capacity - The reservoir capacity below the highest of the elevations representing the top of exclusive flood control capacity, the top of joint use capacity, or the top of active conservation capacity. In the case of a natural lake which has been enlarged, the total capacity includes the dead capacity of the lake. Total capacity is used to express the total quantity of water which can be impounded and is exclusive of surcharge capacity.
Traditional Cultural Property (TCP) - A site or resource that is eligible for inclusion in the National Register Historic Places because of its association with cultural practices or beliefs of a living community.
Turbid - Water clouded as with sediment.
- W -
Water Surface Elevation - The elevation of a water surface above or below an established reference level, such as sea level.