turbines. (2) That stream reach below a dam that is essentially skirted by the flow used to generate electricity.


—That cross section containing the stream that is distinct from the surrounding area due to breaks in the general slope of the land, lack of terrestrial vegetation, and changes in the composition of the substrate materials.


—The mechanical alteration of a natural stream by dredging, straightening, lining, or other means of accelerating the flow of water.


—Maintenance of lateral, longitudinal, and vertical pathways for biological, hydrological, and physical processes.


—The rate of streamflow or the volume of water flowing at a location within a specified time interval. Usually expressed as cubic meters per second (cms) or cubic feet per second (cfs).


—A withdrawal from a body of water by human-made contrivance.

Drainage area

—The total land area draining to any point in a stream. Also called catchment area, watershed, and basin.


—Any flow that exceeds the bankfull capacity of a stream or channel and flows out on the floodplain.


—(1) Land beyond a stream channel that forms the perimeter for the maximum probability flood. (2) A relatively flat strip of land bordering a stream that is formed by sediment deposition.


—(1) The movement of a stream of water or other mobile substance from place to place. (2) Discharge.

Flow regime

—The distribution of annual surface runoff from a watershed over time such as hours, days, or months (See also Hydrologic regime).


—Pertaining to streams or produced by river action.


—The rate of change of any characteristic, expressed per unit of length. (See Slope.) May also apply to longitudinal succession of biological communities.


—In general, all subsurface water that is distinct from surface water; specifically, that part which is in the saturated zone of a defined aquifer. Sometimes called underflow.

The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement