The measurement of diffusion coefficients in the Conwy estuary

Abstract

A continuous point source dye injection technique has been used to study transverse and vertical diffusion in a saline, tidal reach of the Conwy estuary. Data were collected during periods of the flood and ebb tide when the water velocity was fairly steady. The tracing technique was found to be adequate, though suggestions for further improvements have been made. The transverse diffusion coefficients were found to be dependent on flow direction and tidal range for the conditions studied. The data agreed fairly well with other open channel flow data for large width to depth ratios. The vertical diffusion coefficients were smaller for ebb tides than for flood tides, and in all cases were smaller than for homogeneous conditions. © 1981 Academic Press Inc. (London) Ltd.