Tidal scour is "sea-floor erosion caused by strong tidal currents resulting in the removal of inshore sediments and formation of deep holes and channels". Examples of this hydrological process can be found globally.[better source needed] Two locations in the United States where tidal scour is the predominant shaping force is the San Francisco Bay and the Elkhorn Slough.[better source needed] Tidal force can also contribute to bridge scour.[better source needed]