Tidal scour is an erosion

Erosion

Erosion is when materials are removed from the surface and changed into something else. It only works by hydraulic actions and transport of solids in the natural environment, and leads to the deposition of these materials elsewhere...

 process which is carried out by the tidal movement of water.
Examples of this hydrological process can be found in many areas of the world. Two locations in the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 where tidal scour is the predominant shaping force is the San Francisco Bay

San Francisco Bay

San Francisco Bay is a shallow, productive estuary through which water draining from approximately forty percent of California, flowing in the Sacramento and San Joaquin rivers from the Sierra Nevada mountains, enters the Pacific Ocean...

 and the Elkhorn Slough

Elkhorn Slough

Elkhorn Slough is a tidal slough and estuary on Monterey Bay in Monterey County, California. The community of Moss Landing and the huge Moss Landing Power Plant are located at the mouth of the slough on the bay....

. Many other coastal areas around the world are shaped by this process.