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Hydrologic TermsThe hydrologic definitions provided largely are from Langbein andIseri (1960) andPerry (2005).
Aannual maximum peak streamflow The maximum instantaneous discharge value measured during a given water year at a streamflow-gaging station.
D dischargeDischarge is the volume of water that passes a given location within a given period of time. In its simplest concept, discharge means outflow; therefore, the use of this term is not restricted to course or location, and it can be applied to describe the flow of water from a pipe or a drainage basin.drainage area The drainage area of a stream at a specified location is the area, measured in a horizontal plane, that is enclosed by a drainage divide.drainage basin A part of the surface of the Earth where precipitation runs off into the drainage system, which consists of a surface stream or a body of impounded surface water together with all tributary surface streams and bodies of impounded surface water.
F floodAn overflow of water onto or an inundation of lands that are not normally covered by water, and causes or threatens damage.
P peak streamflowThe maximum instantaneous discharge of a stream or river at a given location, and usually occurs at or near the time of maximum stage.
R runoffThat part of the precipitation, snowmelt, or irrigation water that appears in surface streams, rivers, drains, or sewers.
S streamflowThe water discharge that occurs in a natural channel. Although the term "discharge" can be applied to the flow of a canal, the word "streamflow" uniquely describes the discharge in a surface stream course. The term "streamflow" is more general than runoff because streamflow may be applied to discharge whether or not it is affected by diversion or regulation. streamflow-gaging station A site on a stream, lake, reservoir or other body of water where observations and hydrologic data are obtained. The U.S. Geological Survey measures stream discharge at streamflow-gaging stations.
W water yearThe continuous 12-month period from...