Effect of Beach Armoring

On the second day of the Salish Sea program, or group was introduced to the director of Friday Harbor Laboratories, Dr. Megan Dethier. During her presentation, Dr. Dethier introduced us to some of her recent research. During the last couple of years, she has been studying the effects of beach armoring on plants and animals. Because I was interested in her research, I decided to do some research of my own.

What is coastal armoring?

Coastal armoring is any manmade infrastructure that is built on a beach to prevent retreating shorelines. These are often built near houses that are next the ocean to prevent erosion. These walls are often made of steel, wood, concrete, or rock to harden the edge of a beach. They stop the natural movement of the water and sand to slow erosion.

Why is it harmful?

There are multiple negative effects of beach armoring.

1. Lower sediment disposition to water.

The armored walls lessen the amount of sediment that fall into the beaches. This is harmful because many animals are dependent on the sand for spawning ground.

2. Less shade.

Many animals depend on the shade of the trees to lay their eggs. The shade provides a high level of safety for juvenile fish against their predatory birds.

3. Less logs in the beach.

The armored walls lower the number of logs found on the beach. This results in less habitat for animals such as crabs and insects. Because the animals cannot find shelter on the beach, they can be eaten by predators. The loss of these small animals can change the population levels of their predators and prey. Ultimately the entire ecosystem is negatively affected.

Research into the effects of beach armoring is new and the full effects are not understood yet. However, it is clear that beach armoring can lower biodiversity and hurt the ecosystem.