Dams Built to Prevent Coastal Flooding Can Worsen It

Levees and seawalls can increase the risk of flooding in some areas.

Dams, levees, and seawalls are often built to protect coastal communities from flooding. However, these structures can actually increase the risk of flooding in some areas.

One way that dams can increase flooding is by trapping sediment. Sediment is carried by rivers and streams and deposited in deltas. These deltas help to protect coastal communities from flooding by absorbing wave energy and storm surges. When dams are built, they trap sediment upstream, which can starve deltas of the sediment they need to grow and maintain themselves. This can make coastal communities more vulnerable to flooding.

Levees and seawalls can also increase flooding by preventing water from flowing naturally. When water is blocked by a levee or seawall, it can back up and flood areas upstream. This can lead to flooding in areas that would not otherwise be flooded.

In addition, dams, levees, and seawalls can create a false sense of security. When people live behind these structures, they may believe that they are safe from flooding. However, these structures can fail, and when they do, the results can be catastrophic.

There are a number of alternatives to dams, levees, and seawalls that can be used to protect coastal communities from flooding.

These alternatives include:

• Restoring natural habitats, such as wetlands and mangroves.
• Raising the elevation of buildings and infrastructure.
• Relocating people and property away from high-risk areas.

These alternatives are often more effective and less expensive than dams, levees, and seawalls. They also provide a number of other benefits, such as improving water quality, providing habitat for wildlife, and increasing recreational opportunities.

Conclusion

Dams, levees, and seawalls are often seen as the only way to protect coastal communities from flooding. However, these structures can actually increase the risk of flooding in some areas. There are a number of alternatives to dams, levees, and seawalls that can be used to protect coastal communities from flooding. These alternatives are often more effective, less expensive, and provide a number of other benefits.