Mixing Induced by Internal Hydraulic Disturbances in the Vicinity of Sills

Many fjords along the British Columbia and Alaskan coasts are characterized by both a high freshwater discharge and a large tidal range. They also commonly have sills that penetrate well into the stratified near-surface layers, constricting the tidal flow and causing it to accelerate in the region of strong density gradient. An investigation of the nature of mixing in one such fjord, Knight Inlet, began in 1977. The observations were made with at least two vessels, using density and velocity profiling instruments together with high frequency echo sounders. A general description of the processes involved is given by Farmer & Smith (in press).