Study of the sedimentological and rheological properties of fluid mud in the fluvio-estuarine system of the Gironde estuary

Abstract The systematic sampling and measurement of fluid mud made over the past 15 years in the Gironde estuary has enabled both the domain of sedimentological parameters and the salinity of interstitial water variations in this formation to be determined, as well as the time-space distribution of the value of such parameters to be deduced. The programme has been completed by carrying out measurements of the rheological characteristics. The results obtained from this research contribute to the improvement of a large estuary like the Gironde. In particular, the Port of Bordeaux has developed an ultrasonic probe which enables dynamic measurements of density in the fluid mud layers to be made. The calibration and the reliability checks of the ultrasonic probe have necessitated the integration of all the results given by these studies on sedimentological and rheological parameters of the fluid mud. The information provided by this type of research contributes, of course, to the analysis of the estuarine hydro-sedimentological mechanisms. Over and above a purely fundamental knowledge, the results obtained have direct implications for the optimization of the management and operational development of a large estuary.