Wharfs (wharves?) are often built along the side of a river bank or the shoreline. A wharf is a large platform above the water. It can be built on piles or columns or on a solid base. The water alongside a pier needs to be deep enough so that the ship remains afloat as the tide goes out. A wharf has bollards for the ship's mooring lines.
Many wharfs have equipment such as cranes or conveyor belts to move cargo. Some wharfs (wharves) have ramps so that forklifts and vehicles can drive onto roll-on roll-off ships.
The main difference between a pier and a wharf is that a pier goes out to sea while a wharf is built parallel to the shoreline.