The effect of sediment plumes on sonar performance

The increased interest in high frequency sonar operations in shallow water environments has led to a greater need to understand the coastal environment and its impact on the performance of operational sonar systems. Shallow water environments are characterised by high concentrations of suspended solids relative to the open ocean, and previous research (Richards et al., 1996) has shown that the increased sound attenuation due to fine particulate matter can have a significant impact on the performance of high frequency sonars, operating at frequencies of order hundreds of kHz. In this paper we describe the results of a study to investigate the effects of plumes of suspended particulate matter on the performance of high frequency sonars. Such plumes may emanate from estuaries or rivers discharging high sediment loads to coastal waters, or as a result of wave and tidal current action in stirring up bottom sediments. For the calculations described here a simplified 3D suspended sediment transport model has been used to simulate plume dynamics and investigate the dependency on various model parameters