Protecting Shorelines

Waves naturally erode sand along the coast. During storms, waves become much larger and stronger, speeding up erosion and threatening homes and structures built near the shore.

To manage this, people build various structures to control the movement of sand and protect the shoreline from erosion.

Barrier islands provide natural protection to shorelines, especially from storms. Similarly, we can build artificial barriers called breakwaters, which run parallel to the shore. These reduce wave energy before it reaches the beach, helping to protect the coastline.

Groins are rock or concrete walls that extend into the ocean at a right angle to the shore. Once built, they trap sand on one side along the shore, but can cause increased erosion on the other.

Seawalls are also built onshore parallel to the shore to block waves from eroding the land behind them.

While these structures can slow erosion, they don’t always work perfectly. The powerful 2011 tsunami in Japan washed over seawalls, demonstrating that even strong human-made barriers have their limits.