An analysis of the backscattered signal allows us to determine the sediment concentration. The transducer array contains three transducers with 3 discrete acoustic frequencies, which allows us to determine a range of particle sizes in the sediment. The instrument is controlled by an on-shore computer which stores the data. Researchers must be present at measurement site during runoff. A large degree of uncertainty exists.
Acoustic measurement are easier and more precise and the measurements can be made remotely.
The first step in developing such an instrument is to verify that we can acoustically measure sediment concentration. To do this we have built a vertical flume which allows us to acoustically and physically measure sediment concentrations simultaneously. By comparing the results of the two independent measurements we can establish the acoustic method and then develop a portable system for field use. This vertical flume is known as the Suspended Sediment Calibration System . The images below show the apparatus, clicking on different sections of the image on the left will bring up more details about the apparatus.