Where in the channel is the SW measuring the water velocity?
When mounted properly along the axis of the channel with one beam pointed upstream and one downstream, the SW will measure the average velocity from an imaginary layer about 0.4 ft (0.12 m) above the transducer head, all the way to the surface. This ability to measure water velocity all the way to the waters surface is a key technical innovation of the SW. The system first uses the vertical beam to measure the distance to the water surface. The SW will then automatically compute the velocity cell end based on this measured distance. As such, as the water level changes, the velocity measurement will automatically adjust to always measure to the surface no matter how frequently or rapidly the level changes.
