Oct 7, 2024

What is a Breakwater? A Powerful Solution for Coastal Preservation

As weather patterns change and coastal erosion gets worse, breakwaters are now more than ever vital for protecting our shores. So what is a breakwater? In simple terms, it’s a solid barrier built offshore to help protect shorelines from erosion. Coastal areas, with their natural beauty, diverse ecosystems and beachside communities, are at high risk from the ocean waves slowly wearing the land away and damaging buildings. Breakwaters help by reducing the impact of the waves that reach the shore, making them essential in coastal protection. In this article, we’ll explore why breakwaters are important, the different types that are used, and how they influence coastal environments.

So what is a breakwater exactly? It’s basically a large wall built out in the water, usually parallel to the shore, to protect the coastline from the currents, tides and storms. It acts like a barrier that slows down the waves before they reach the shore, creating calmer waters behind the wall which means less erosion and damage to the beach. On top of that, these calm waters are perfect for harbors, marinas, and recreational activities.

Main Types of Breakwaters

Breakwaters, similar to bulkheads, can be built in different ways, depending on the conditions they’ll face and what they’re meant to do. When exploring what is a breakwater, it’s helpful to know the main types. Each type has its own advantages and is chosen based on factors like wave strength, environmental considerations, and the specific needs of the coastline. Here are the three main types:

Fixed Breakwaters: These are permanent structures made from materials like rock, concrete, or stone. They’re designed to last a long time and are usually used in areas where the waves are strong, and there’s a lot at stake, like protecting important infrastructure. Fixed breakwaters offer solid, reliable protection and are a popular choice because they can handle severe weather. The downside? They can be expensive to build and might have a noticeable impact on the environment because of their size and permanence. Over time, they’ll also need some maintenance to fix any wear from constant wave action.

The most common type of fixed breakwaters are rubble or mound breakwaters. These are made by piling up loose rocks or stones to block and weaken waves. Construction often involves heavy machinery like cranes or barges to transport and position the rocks. The base is made of large, heavy rocks or stones to provide strength and stability. Smaller stones or rubble are placed on top of the larger rocks, forming a slope that allows the structure to absorb the wave energy. The water is still able to flow through the wall, just with a lot less force.

Floating Breakwaters: These breakwaters float on the surface of the water and are anchored to the seabed by heavy chains or cables. In some instances, large piles are used. Floating breakwaters move with the water and are less intrusive than the fixed kind. They are usually used in areas with gentler waves or when it’s important to minimize environmental changes. They’re great for protecting marinas and small harbors from waves without drastically altering the landscape. Because they aren’t fixed in place, floating breakwaters can be adjusted or moved around more easily, giving them more flexibility than fixed structures.

Submerged Breakwaters: These sit below the water’s surface and are less visible, which can be better for maintaining the natural look of the area. Submerged breakwaters still do a good job of cutting down wave energy and are often chosen when preserving the appearance of the coastline is a priority. They help protect the shoreline while maintaining the natural beauty of the coastal environment. Submerged breakwaters can even support marine life by creating habitats for fish and other species. Like fixed breakwaters, though, they’ll need regular monitoring and maintenance to make sure they stay in good condition.

What is a Breakwater vs. a Seawall?

A seawall is built directly along the shore to take the full force of the waves as they crash, preventing erosion at the point of contact. Breakwaters, however, are typically built offshore, reducing the waves’ energy before they even make it to the shore. They both protect coastlines, they just work in different ways.

Seawalls are usually made from tough materials like concrete or steel and are designed to handle the heavy impact of waves. Breakwaters, on the other hand, act like a buffer, creating calm waters behind them, which helps protect the shoreline with less direct impact. When learning what is a breakwater versus a seawall, the key difference is that breakwaters are built offshore, while seawalls are constructed directly on the shore. Understanding this difference is important when deciding which option is best for a specific coastal area.

What Happens to a Beach When a Breakwater is Built?

Breakwaters can make existing beaches bigger or even create new ones. This happens because the calmer waters behind the breakwater allow sand and other materials carried by the waves to settle, gradually building up over time. This extra sand can be a good thing because it helps to reinforce the shoreline and adds another layer of protection against erosion.

But, it can also affect how sediment moves along the coast, which could cause erosion in other areas. It’s important to balance the benefits of a growing beach with the need to protect the rest of the shoreline. Managing this carefully is important to keep the beach and surrounding areas healthy in the long run. When learning about what is a breakwater, it’s important to understand how it affects not only the beach but also the land around it. 

Why Does Sand Build Up Behind a Breakwater?

The reason sand builds up behind a breakwater is pretty simple: the breakwater slows down the water, which means it can’t carry as much sediment. As the water loses speed, sand and other particles drop out and settle on the protected side of the breakwater. Over time, this creates a buildup of sand, often forming sandbars or even new stretches of beach. This sand buildup is generally a positive outcome for the stability of the coastline you’re trying to protect, because it reinforces the shore against future erosion.

This process can also shift sediment away from other areas, leading to erosion elsewhere along the coast. If too much sand accumulates in one area, it can affect the local ecosystem, alter navigation routes for boats, or even disrupt recreational activities. And not enough sediment movement beyond the breakwater can take away too much sand from areas downstream (called down-drift erosion), leading to more erosion further down the coast with potential damage to infrastructure or natural habitats. Regular monitoring, along with dredging or sand redistribution, is often necessary to maintain a healthy balance along the coast.

Why Is the Water Calm Behind Breakwaters?

When waves hit the breakwater, they either crash against it or are directed away from the protected area, decreasing both the height and force of the waves, creating a peaceful zone on the side facing the shore. This calm water is perfect for docking boats, swimming, and other recreational activities. In harbors or marinas, the calm water allows ships and boats to dock safely without being pushed around by strong waves. This means less risk of damage to both boats and docks. Breakwaters are especially important during storms or high seas when protection is most needed.

The calm conditions can promote marine life by creating a stable and sheltered environment for different species to thrive. Many fish, crustaceans, and other aquatic organisms thrive in areas with less wave action, where they can find shelter, feed, and reproduce without being constantly disturbed by strong currents. In some cases, breakwaters can even promote the development of new ecosystems, as the calmer waters encourage the growth of plants and the settlement of small organisms. Over time, these habitats can become important ecological zones, supporting a diversity of marine life.

The quiet water behind the breakwater wall makes the area better for recreational use. Beaches protected by breakwaters often become popular spots for swimming, kayaking, paddleboarding, and other water sports, as people are drawn to the safety and peace of the calmer waters. For coastal communities that rely on tourism, the presence of a breakwater can enhance the appeal of local beaches, contributing to the local economy. So when exploring what is a breakwater, you need to understand that by reducing wave energy, it creates a peaceful zone that protects the water behind it.

Do Breakwaters Prevent Flooding?

When asking what is a breakwater, it’s important to understand that while they can’t completely prevent flooding, they do help decrease the risk. Breakwaters are great at reducing the impact of waves and storm surges, which is why they help prevent coastal flooding. By absorbing wave energy before it hits the shore, breakwaters lower the height and strength of the waves, which cuts down the chances of flooding in vulnerable areas. This is especially good for protecting homes, businesses, or natural habitats that might otherwise be overwhelmed by high tides and storm surges.

Breakwaters are extra important in areas that experience extreme weather, where even a small reduction in wave energy can make a big difference. In addition to preventing flooding, breakwaters help keep the natural shape of the coastline, which is crucial in preventing erosion that would make flooding worse. However, breakwaters alone aren’t enough to completely stop flooding during times of rising sea levels or heavy rainfall.

While they are essential for storm surge management, breakwaters work best when used as part of a comprehensive flood control strategy. Communities might combine breakwaters with other defenses, like seawalls and levees, or natural solutions like restoring wetlands, to create a more complete protection system. Regular inspections and maintenance are also key to making sure breakwaters keep working well, especially as weather patterns and sea levels change.

Are Breakwaters Environmentally Friendly?

The environmental impact of breakwaters is something we have to think about carefully. On the positive side, breakwaters do a great job of protecting coastlines and preventing erosion to infrastructure. This protection is especially important for saving fragile ecosystems like wetlands and coastal forests that could otherwise erode away. However, breakwaters can also interfere with the natural flow of sand and water, changing how coastal ecosystems work and impacting the animals that rely on them.

Sometimes, breakwaters can cause unexpected problems, like changing the shape of beaches or disturbing marine life habitats. The construction process itself, with heavy equipment on the seafloor, can disrupt or harm species. But with eco-friendly materials and good planning, breakwaters can limit harm to the environment. In fact, some are even made to work as artificial reefs, providing homes for marine life. These eco-friendly designs help protect the coast while also supporting efforts to conserve nature. To fully understand what is a breakwater, it’s vital to consider how it affects the environment. 

Challenges and Disadvantages of Breakwaters

While breakwaters are essential for coastal protection, they come with their own set of challenges. One big problem is that they can block the natural movement of sand along the shoreline. This can cause erosion in unprotected areas further down the coast, meaning one part of the beach gets protected while another part starts to erode more quickly.

Another drawback is the high cost of construction and maintenance. Breakwaters require strong materials like rock, concrete, or steel, which are expensive to source and build. Over time, the constant force of waves means breakwaters need repairs or upgrades. And in areas with harsh weather, this maintenance can be frequent and costly. Additionally, understanding what is a breakwater involves knowing its potential environmental impact.

Like we said, by altering water flow and sediment movement, breakwaters can unintentionally affect nearby marine habitats and create navigation hazards. Dredging or moving sand during construction may further disturb the environment. To reduce these problems, engineers must carefully plan where and how breakwaters are built, making sure they protect the coast without harming natural processes and ecosystems.

Final Considerations

So what is a breakwater? It’s a crucial tool for coastal protection that not only prevents erosion but also creates calmer waters for human use and marine life. Breakwaters are key to protecting coastlines, offering benefits like less erosion and quieter waters. While they do come with some challenges, such as environmental impacts and maintenance costs, the protection and stability they offer make them well worth it.

If you’re looking to protect your coastline, you want a partner with experience and a proven track record. With over 70 years in marine construction, Lamulle Construction has the expertise to design and build reliable breakwaters tailored to your needs. Contact us today to learn more about how we can help safeguard your shoreline for years to come.

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