Channel stability in the tay estuary: controls by bedrock and unconsolidated post-glacial sediment

Borehole and geophysical data have been collated for two sections across the Tay estuary on the lines of the road and rail bridges at Dundee. Geological reconstructions reveal a complex late-glacial and Holocene fill resting on a basement of Devonian sandstones and lavas. Comparative analyses of bathymetric charts (1816–1970) have enabled areas of present-day relatively stable and unstable bed to be identified. Stable areas are underlain by either gravels or partially compacted clays; unstable areas by loose, coarse to fine, sands. Non-migratory channels coincide with the stable areas; shifting sand banks and migratory channels occur elsewhere.