Geological Survey (USGS) streamgages measure stage and consist of a structure in which instruments used to measure, store, and transmit the stream-stage information are housed. The discharge measurement-obtaining periodic measurements of discharge (the quantity of water passing a location along a stream)ģ. The stage-discharge relation-defining the natural but often changing relation between the stage and discharge using the stage-discharge relation to convert the continuously measured stage into estimates of streamflow or discharge Measuring stream stage-obtaining a continuous record of stage-the height of the water surface at a location along a stream or riverĢ. The gage is marked in 1/100th and 1/10th foot intervals.ġ. You can get an idea of what stream stage is by looking at a picture of a common staff gage, which is used to make a visual reading of stream stage.

The zero level is arbitrary, but is often close to the streambed.

Stream stage (also called stage or gage height) is the height of the water surface, in feet, above an established altitude where the stage is zero. Stream stage is important in that it can be used (after a complex process described below) to compute streamflow, or how much water is flowing in the stream at any instant.

Often during a large rainstorm you can hear an announcement on the radio like 'Peachtree Creek is expected to crest later today at 14.5 feet.' The 14.5 feet the announcer is referring to is the stream stage. The USGS has been measuring streamflow on thousands of rivers and streams for many decades and by reading this set of Web pages you can find out how the whole streamflow-measurement process works.

The USGS operates over 8,200 continuous-record streamgages that provide streamflow information for a wide variety of uses including flood prediction, water management and allocation, engineering design, research, operation of locks and dams, and recreational safety and enjoyment.Īs you're enjoying yourself sitting on the peaceful bank of a local river, one question you may ask yourself is 'How much water is flowing in this river?' You've come to the right place for an answer. Geological Survey (USGS) started its first streamgage in 1889 on the Rio Grande River in New Mexico to help determine if there was adequate water for irrigation purposes to encourage new development and western expansion.

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