Surface Water Quantity ADCP

Text below is based on content made available by U.S. Geological Survey (USGS)'s page on how streamflow is measured

What is "Acoustic Doppler Current Profiler"?

The Acoustic Doppler Current Profiler (ADCP) uses the Doppler Effect to determine water velocity by sending a sound pulse into the water and measuring the change in frequency of that sound pulse reflected back to the ADCP by sediment or other particulates being transported in the water. The change in frequency, or Doppler Shift, that is measured by the ADCP is translated into water velocity. The sound is transmitted into the water from a transducer to the bottom of the river and receives return signals throughout the entire depth. The ADCP also uses acoustics to measure water depth by measuring the travel time of a pulse of sound to reach the river bottom at back to the ADCP.

How is it deployed?

1. Spot measurement: To make a discharge measurement, the ADCP is mounted onto a boat or into a small watercraft with its acoustic beams directed into the water from the water surface. The ADCP is then guided across the surface of the river to obtain measurements of velocity and depth across the channel. In this way, ADCP can be used to develop a more accurate rating curve than using a current meter.
2. Continuous measurement: The ADCP is fixed (usually at the side or bottom of the channel) to continuously measure the flow profile. This data is then transmitted to for real time analysis, such as integration into a real-time flood warning system.

Main costs: The main cost with ADCP is the equipment itself, and depending on factors such as power (depending on size of river) and GPS integration, the cost range should be between $10,000 to $30,000.