Glossary of Terms

flood stage

1. The Stage at which overbank flows are of sufficient magnitude to cause considerable inundation of land and roads and/or threat of significant hazard to life and property.
2. The Stage at which the flow in a flood control project is at maximum design capacity (U.S. Corps of Engineers "Project Flood Plane"). At this level there is a minimum freeboard of 3 feet to the top of levees.

hydrologic area

1. A geographical area representing part or all of a surface drainage basin or distinct hydrologic feature such as a reservoir, lake, etc.

monitor stage

1. The Stage at which initial action must be taken by concerned interests (livestock warning, removal of equipment from lowest overflow areas, or simply general surveillance of the situation). This level may produce overbank flows sufficient to cause minor flooding of low-lying lands and local roads.
2. The Stage at which patrol of flood control project levees becomes mandatory, or the Stage at which flow occurs into bypass areas from project overflow weirs.

precipitation, accumulated

1. A sensor type where the field measuring device accumulates precipitation during the water year. Some stations accumulation tanks periodically dump the accumulated precipitation to make room for more precipitation. This may cause the value transmitted to jump backward several inches. The value usually accumulates or gets larger until it is reset. A reset may occur if a technician visits the site or it is near the beginning of the season. The dates that designate a season varies according to different agencies (ie. July-June, October-September). Generally, this sensor type is used for real-time collection duration of hourly or event data.

precipitation, tipping bucket

1. A sensor type where the field measuring device uses a calibrated bucket that tips when full of precipitation. The amount of precipitation at which the device tips is usually 0.04 inches. There are some gages that tip at 0.01 inches. The value usually accumulates or gets larger until it is reset. A reset may occur if a technician visits the site or it is near the beginning of the season. The dates that designate a season varies according to different agencies (ie. July-June, October-September). Generally, this sensor type is used for real-time collection duration of hourly or event data.

precipitation, incremental

1. A sensor type where the value is either calculated from real-time data or manually entered from an observers report. Generally, this sensor type is used for daily and monthly data.

river basin

1. A part of the earth's surface which is occupied by a drainage system which consists of a surface stream with all its tributaries and impounded bodies of water. Also known as watershed, catchment area, and drainage area.

river stage

1. The height of a water surface above an established "zero" plane, or datum.

sensor

1. A device for indicating the magnitude or position of a thing in specific units, when such magnitude or position undergoes change. For example: the elevation of a water surface, the velocity of flowing water, the pressure of water, the amount or intensity of precipitation, the depth of snowfall, etc.
2. The act or operation of registering or measuring the magnitude or position of a thing when these characteristics are undergoing change.
3. The operation, including both field and office work, of measuring the discharge of a stream of water in a waterway.

station

1. A particular site on a stream, canal, lake, or reservoir where systematic observations of stage or streamflow are obtained.

Other Glossaries

• Glossary of National Weather Service (NWS) Terms, Phrases, and Abbreviations