Waves are the primary force shaping beaches. Their energy, determined by wave structure, moves beach sediment, dramatically altering the beach's form.
How Wave Energy Reshapes Beaches
The process begins as waves approach the shoreline. As the water depth decreases, a phenomenon called shoaling occurs, increasing wave height. [^1, ^2] This increase in energy leads to the breaking of waves, a crucial stage in beach modification. [^3]
The breaking waves generate powerful forces that erode the coast. [^3] These forces suspend and transport sediment, impacting the beach's shape in several ways:
- Erosion: Breaking waves can erode the coastline, removing sand and other materials. Steeper beaches tend to experience more destructive waves, leading to increased erosion. [^8]
- Sediment Transportation: The backwash of waves carries eroded sediment along the beach, leading to deposition in other areas. This constant movement of sand and other materials shapes the beach's profile. [^9]
- Deposition: Areas with reduced wave energy experience sediment deposition, building up sandbars and altering the overall shape. Constructive waves, common on wide beaches, contribute significantly to this process. [^8]
The interplay between erosion and deposition, driven by wave energy, continuously reshapes the beach. Even seemingly minor changes in wave intensity or direction can have significant cumulative effects over time. For instance, strong winds can create currents that influence wave patterns, directly impacting the beach's shape. [^10] The angle at which waves strike the beach also plays a role, with waves hitting at an angle resulting in a more pronounced longshore drift of sediment. [^9]
In summary, the constant interaction between waves and the shoreline, driven by the energy carried by waves, results in the dynamic and ever-changing shape of beaches. The magnitude of these changes depends heavily on the wave's energy, which is influenced by factors like wind strength and ocean depth.
[^1]: Waves are the dominant force driving the nature of a beach. The energy carried through waves moves beach sediment and transforms beach shape. (Source: Multiple sources including NPS article)
[^2]: This process is called shoaling, and it causes the height of waves to increase... (Source: manoa.hawaii.edu/ExploringOurFluidEarth)
[^3]: Coastal erosion is initiated by the movement of water in the form of high waves and strong currents. Breaking waves erode the coast by suspending sediment... (Source: pubs.usgs.gov/of/2003/of03-337/waves.html)
[^8]: Steep beaches create destructive waves, which will be higher and crash nearer to you if you are paddling; expect constructive waves on a wide... (Source: www.countrylife.co.uk/nature/all-you-need-to-know-about-waves-229832)
[^9]: Sand grains carried by the rush and backwash of the waves are moved along... (Source: earthobservatory.nasa.gov/world-of-change/CapeCod)
[^10]: This in turn influences the shape of coastal landforms up and down the beach. Waves that drive these currents are usually wind waves and/or... (Source: www.reddit.com/r/interestingasfuck/comments/jhp4fv/zlatni_rat_beach_in_croatia_changes_shape_due_to/)
