Quantifying Digitizer Design Requirements for a Sediment-Generated Noise Instrument

Coarse sediment that rivers move along their bed, or bedload, generates noise by interparticle collisions, otherwise known as sediment-generated noise (SGN). Development of a purpose-built low-power acoustic detector of underwater bedload transport would benefit water managers, hydrologists, and conservation efforts targeted at fluvial environments. Such a detector needs to have a long battery life in order to run autonomously over long periods; therefore, the sampling frequency and bit depth should be minimized in order to save power. This letter provides an estimate of how bit depth and sample rate affect SGN detection by using algorithms analogous to a variety of published SGN detection methods. We find that 12 bits and 11 kHz are sufficient to meet a median of 5% difference for all features chosen.