Whole flow field dynamics and velocity pulsing within natural sediment-laden underflows

Sediment-laden density underflows are important agents of erosion and deposition and are especially significant in the management of human-made reservoirs, pollutant dispersal, and sediment deposition in the world's oceans. Quantification of continuous, sediment-laden underflows in Lillooet Lake, British Columbia, shows that the underflows descend along a distinct plunge line but, although the input from the source is constant, adopt a distinct pulsing in their velocity structure. Such velocity pulsing will produce temporally and spatially varying bed shear stresses, sediment erosion and/or deposition, and fluid mixing, and represents a central property of underflows that must be incorporated into models of density current behavior.