Holding Back the Ocean: How Hydraulic Structures Help Prevent Coastal Erosion
February 28, 2024
Introduction: The Battle Against the Sea
The ocean is a powerful force that has been a constant challenge for mankind. Throughout history, we have built our cities and towns near the coast for easy access to trade and resources, but we have also learned the hard way that living so close to the sea comes with its own set of risks. Coastal erosion, caused by the relentless pounding of waves, poses a constant threat to our livelihoods and our very existence. Luckily, through advancements in hydraulic engineering, we have found ways to fight back and protect our shorelines. In this chapter, we will explore the various hydraulic structures used to contain and control the sea, including breakwaters, jetties, and seawalls.
Breakwaters: A Shield Against the Surge
Coastal communities across the globe have found solace in the form of breakwaters. These structures act as a protective barrier, separating the shore from the sea. The primary purpose of breakwaters is to absorb the energy of incoming waves, preventing them from causing erosion or damage to the coast. They are usually built parallel to the shoreline, but can also be constructed in a curved shape to provide additional protection from storms and strong currents.
The construction of breakwaters has evolved over time, from natural structures such as reefs and sand dunes, to man-made structures made of concrete and steel. They are often accompanied by other coastal protection measures, such as seawalls and jetties, to create a comprehensive defense system against the forces of the sea.
One of the most significant benefits of breakwaters is their ability to create calmer waters near the shore. This allows for safe harbor in ports and marinas, making it easier for ships and boats to come and go without being at the mercy of rough seas. This, in turn, has a positive impact on the local economy, as it encourages trade and tourism.
Jetties: A Guide for Safe Navigation
Unlike breakwaters, jetties are built perpendicular to the shoreline, extending into the water and often meeting at a “T” or “L” shape. Their main purpose is to provide a navigational aid for ships and boats, guiding them safely into harbors and ports. But, like breakwaters, jetties also serve as a protective barrier, reducing the erosion caused by longshore drift (the movement of sediment along the coast due to currents and winds).
Jetties are usually made of concrete, but historically, they have also been constructed with wood or rock. In recent years, there has been a shift towards using environmentally-friendly materials, such as recycled plastic, for jetty construction.
Another important aspect of jetties is their role in managing sand flow along the coast. They can be designed to trap sediment and create calm areas for beach restoration or expansion. This helps to maintain the overall balance of the beach ecosystem and protects the coast from erosion. Jetties have also become popular fishing spots, making them not only functional structures but also recreational ones.
Seawalls: The Last Line of Defense
Seawalls are a type of coastal defense that is constructed parallel to the shoreline, providing a barrier between the sea and the land. Unlike breakwaters and jetties, which are partially submerged, seawalls are completely above water, making them highly visible from the shore. These structures are typically made of concrete, rock, or steel and can range in height, depending on the level of protection required.
The main purpose of seawalls is to absorb the energy of incoming waves, protecting the shoreline from erosion and flooding. They are often the last line of defense against severe storms and high tides, providing vital protection for coastal communities.
But, like other hydraulic structures, seawalls also have their downsides. Building a seawall can often create a domino effect, causing erosion and damage to adjacent areas that are not protected. It is a delicate task to strike a balance between protecting one area and not causing harm to another. Additionally, seawalls do not address the root cause of coastal erosion, which is often due to human interference and disruption of natural sediment flow.
Conclusion: The Future of Coastal Protection
As we continue to battle against rising sea levels and unpredictable weather patterns, the importance of hydraulic structures in coastal protection cannot be overstated. Breakwaters, jetties, and seawalls have proven to be effective measures in holding back the ocean and protecting our shorelines. But, as we move forward, it is crucial that we also consider the long-term consequences of these structures on the environment and explore more sustainable and eco-friendly options.
As engineers and scientists continue to push the boundaries of hydraulic engineering, we can look forward to a future where our coasts are better protected, and our relationship with the sea is one of balance and harmony. One thing is certain, with innovation and creativity, we will continue to find ways to hold back the power of the ocean and ensure the safety and prosperity of our coastal communities.
