How do large tidal ranges affect the design of harbor structures?

Large tidal ranges significantly impact the design of harbor structures by complicating cargo handling and increasing construction costs. When the variation between low and high water is extreme, the resulting changes in the level of ship decks and hatches can create unacceptable difficulties for loading and unloading cargo.1

To address these challenges, engineers may employ the following strategies:

• Enclosed Docks: In areas with large tidal ranges, quays are often constructed as enclosed docks where the water level is kept constant. Access to these areas is managed through locks, which allow ships to enter and exit while maintaining a stable internal water level.1
• Structural Dimensions: If open quays are used, the quay walls must be tall enough to span the distance from the lowest navigable seabed level at low tide to an adequate freeboard above the highest high tide. This can lead to massive, uneconomical wall dimensions.1
• Impounding Pumps: To maintain necessary water depths or keep levels above the highest tide, engineers may install pumps to lift water into the dock area.1
• Hydraulic Modeling: Because tidal variations can cause issues like siltation or scour, engineers use hydraulic models to simulate tidal effects and test the impact of harbor modifications before construction.2