Hydrodynamic scour

Hydrodynamic scour is the removal of sediment such as silt, sand and gravel from around the base of obstructions to the flow in the sea, rivers and canals.

It is a notable cause of bridge failure and a problem with most marine structures supported by the seabed in areas of significant tidal and ocean current.

The flow changes that occur in the vicinity of the substrate may cause differential movement in the bed materials near the obstruction.

The magnitude of these changes varies with stream velocity, feature shape and substrate character.

In conditions of high stream velocities, mobile bed materials, and poorly streamlined structures scour depths can be quite deep.