Flanking erosion is a type of increased erosion that occurs at the ends of coastal defense structures like seawalls.
Coastal structures, such as seawalls, are designed to protect the land behind them from erosion. However, they can sometimes lead to unintended consequences in unprotected areas nearby.
Where Flanking Erosion Occurs
According to the reference, flanking erosion takes place at the ends of seawalls. This means the problem doesn't happen along the face of the seawall itself, but rather in the adjacent areas where the seawall stops and the natural coastline or unprotected bluffs continue.
How Flanking Erosion Happens
The mechanism involves the interaction of waves with the seawall:
- Wave energy, which would normally impact the protected area, can be reflected from the seawall.
- This reflected energy is directed sideways along the shore.
- This concentrated energy then hits the coastal bluffs or beach areas without protection at the ends of the seawall.
This process causes these unprotected adjacent areas to erode faster than they would if the seawall were not present.
In essence, while the seawall protects the land directly behind it, it can intensify erosion on its "flanks" or sides.
Key Characteristics of Flanking Erosion:
- Occurs specifically at the ends of seawalls.
- Caused by reflected wave energy from the seawall.
- Leads to increased erosion in adjacent, unprotected coastal areas.
- Can cause coastal bluffs without protection to erode faster.
Understanding flanking erosion is crucial when designing and implementing coastal protection measures, as it highlights the need to consider the potential impacts on the surrounding environment.