In winter, tidal outflow from the Leschenault Estuary forms a buoyant sheared stratified plume in Koombana Bay on each outgoing tide. The turbulence in the plume and the local entrainment into the plume are examined based on measurements collected in an intensive field program. Coherency measurements between horizontally separated sensors are used to examine the anisotropy of the turbulence. The effects of viscosity and buoyancy on the turbulence are studied using an activity diagram which is also an indicator of the mixing efficiency and total mixing. The Osborne-Cox model is tested and found to be valid in the plume. ¿ American Geophysical Union 1989