Blonde Girl At The Shore Posing On The Quay

A wharf commonly comprises a fixed platform, often on pilings. Commercial ports may have warehouses that serve as interim storage areas, since the typical objective is to unload and reload vessels as quickly as possible. Where capacity is sufficient a single wharf with a single berth constructed along the land adjacent to the water is normally used; where there is a need for more capacity multiple wharves, or perhaps a single large wharf with multiple berths, will instead be constructed, sometimes projecting into the water. A pier, raised over the water rather than within it, is commonly used for cases where the weight or volume of cargos will be low.
Smaller and more modern wharves are sometimes built on flotation devices (pontoons) to keep them at the same level to the ship even during changing tides.
In everyday parlance the term quay is common in the United Kingdom and many other Commonwealth countries, whereas the term wharf is more common in North America. In commercial/industrial usage wharf is typically avoided with quay being used to refer to the berthing areas, and port and terminal being used to refer to the overall structures and locations. Merriam-Webster's Dictionary of Synonyms quotes the New York Times as saying "a quay is a docking facility at which vessels lie parallel to the shoreline." In some contexts wharf and quay may be used to mean pier, berth, or jetty, though these uses are not addressed.
In old ports such as London (which once had around 1700 wharves ) many old wharves have been converted to residential or office use.