Erosion of muddy inter-tidal sediments in the Severn Estuary, UK is frequently expressed by the development of extensive streamwise ridge-furrow structures. In most cases the bottoms of the furrows have accumulations of coarse sediments which are thought to be responsible for erosion. The ridge-furrow structures are independent of bed irregularities and are thought to arise through the action of secondary flows. Working with Professors Paul Carling and Carl Amos at the University of Southampton and Dr Paul Bell at the Proudman Oceanographic Laboratory field studies have been undertaken to examine two hypotheses:
the ridges were planned off in the past by a large flow event and then re-sedimented and are now in equilibrium with the imposed flow regime; or
the ridges repeatedly cut and re-sediment above an older undisturbed core as tidal stresses change through Neaps and Springs.
There have been a number of field measurement campaigns examining flow turbulence and mud sedimentology. These have been supported by laboratory studies of mud structures using x-ray diffraction and mud erodibility using a mini-flume.
