Stream Stage

The height or elevation of the stream's water surface above a reference elevation (sea level, gage level) is called the stream stage. Stream stage can be easily measured manually or by instrumentation left in the field. Floating gages use a buoyant ball which rises with rising water (increasing water surface elevation) and falls with falling water (decreasing water surface elevation). Pressure transducers can be installed below the water surface to monitor increasing pressure as the water level rises and decreasing pressure as the water level falls. All of these devices can be connected to data loggers to record the water level over time.

Locations along streams which are monitored for stage over time are called gaging stations. Many gaging stations are located throughout the United States and are monitored and maintained by the United States Geological Survey (USGS).

 

USGS Gaging Station on Rio Grande