Measurement of fluid mud layers - field instrument developments

Results from field measurements obtained during port development studies in certain turbid coastal locations suggested that relatively weak wave activity over shallow muddy areas can create a near-bed layer of fluid mud which is transportable by modest tidal currents into dredged navigation channels, harbours and berthing areas. Subsequent laboratory flume studies carried out on the local mud confirmed this hypothesis. To monitor the movement of a near-bed turbid layer it is necessary to know the thickness, density, speed and direction of movement within precise limits. It is desirable also to know how the layers move in relation to the water column above. To meet these requirements, field instrumentation has been developed at HR. This report describes the instrumentation and the results obtained during field trials of the equipment.