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Speaker: The United States Geological Survey collects stage data at rivers and streams in Arizona. The stage data collected by the stream gauge is converted to discharge by a mathematical formula called radium after the data is transmitted to the office.
Because channel or stream bed conditions change during flow events, personnel maintaining the gauges are required to make discharge measurements to calibrate the rating. Calibrating the rating makes the overall discharge more accurate.
The discharge measurements are represented by the asterisk on the hydrograph to the left of the screen.
Personnel use different techniques to measure discharge depending on the amount of flow, as shown on the video to the right.
At higher flows, a bridge board is used whereas at lower flows, the measurement is made by wading the channel.
Title: Explaining Flood Measurements
Description: Explaning why USGS streamgagers make discharge measurements.
Location: AZ, USA
Date Taken: 3/22/2010
Video Producer: U.S. Geological Survey
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