Seawall in canal in South Florida.

Seawall Erosion and Prevention efforts to detain rising waters

Coastal and shoreline erosion is a growing concern for communities worldwide, threatening both natural environments and human infrastructure that is worth money. With rising sea levels and the increasing frequency and intensity of storms, it has become imperative to find effective solutions to combat this erosion.

One such solution, seawalls, is often implemented to safeguard against the destructive forces of nature. In this article, we will explore the complex issue of seawall erosion and prevention, covering the causes of coastal and shoreline erosion, the ideal fill material for seawalls, the function of seawall erosion control structures, and the impacts of seawalls on erosion.

We will also discuss the innovative approach of Seawall Foam repair in addressing voids and stabilizing soils behind seawalls. For example in Miami and South Florida, seawalls need constant maintenance.

Seawall overflow in the neighborhood of Riverside Park in Fort Lauderdale

What Causes Coastal and Shoreline Erosion?

Coastal and shoreline erosion can be attributed to several interrelated factors. To understand the erosion problem and why seawalls are essential, it’s crucial to delve into the root causes.

According to a report by the National Oceanic and Atmospheric Administration (NOAA), the primary causes of coastal and shoreline erosion are:

Seawall in Galveston.
Seawall in Galveston.

Wave Action

The force of waves, especially during storms, can eat away at coastlines over time. This is a natural process, but it’s exacerbated by human activities and rising sea levels.

Storm Surges

Storms, including hurricanes and typhoons, create powerful surges of water that inundate coastal areas, causing significant erosion. The severity of the damage depends on the intensity of the storm.

Sea Level Rise

Global warming has led to rising sea levels due to the melting of polar ice caps and glaciers. Higher sea levels make coastlines more susceptible to erosion and inundation.

Human Activities

Human interventions such as the construction of buildings, marinas, and other infrastructure can disrupt natural coastal processes. Coastal development often results in increased erosion due to reduced sediment flow and the blocking of natural shoreline movements.

Sediment Depletion

Dredging and sand mining for construction purposes can strip coastal areas of the sediment that naturally replenishes shorelines, leading to increased erosion.

Climate Change

The changing climate patterns, including increased rainfall and temperature, can contribute to erosion by altering natural sediment transport processes.

A brand new seawall on a canal in Florida.
A brand new seawall on a canal in Florida.

What is a Seawall Erosion Control Structure?

Seawall erosion control structures, commonly known as seawalls or bulkheads (but bulkhead refers to the top of the seawall), are engineered barriers constructed along coastlines and shorelines to protect against erosion, storm surges, and the encroachment of the sea. These structures are typically made of concrete, steel, or other durable materials.

According to the Coastal Resource Management Agency (CRMA), “Seawalls are designed to reduce the impact of wave energy and stabilize the shoreline.” They serve as a buffer, absorbing the force of waves and reducing erosion in the area they protect.

Seawalls come in various shapes and sizes, including vertical walls, curved structures, and riprap (piles of rock or concrete) revetments. The choice of design depends on the specific needs of the location and the expected wave conditions.

The primary functions of seawall erosion control structures are to:

Protect Coastal Properties: Seawalls act as a barrier, safeguarding homes, businesses, and infrastructure from coastal erosion. Without them, properties near the shore are at risk of being damaged or washed away.

Stabilize Shorelines: By absorbing the energy of incoming waves, seawalls help stabilize the shoreline, reducing the rate of natural erosion and protecting delicate ecosystems.

Reduce Storm Damage: During storms and hurricanes, seawalls mitigate the impact of storm surges, which can cause catastrophic flooding and erosion. This can save lives and prevent widespread destruction.

Enhance Beachfronts: In some cases, seawalls are built to create recreational areas such as promenades or beachfronts. They can also serve as foundations for seawall walkways and roads.

Do Seawalls Make Erosion Worse?

Seawalls are undoubtedly effective at protecting properties and infrastructure from immediate coastal erosion. However, they are not without drawbacks, and in some cases, they can exacerbate erosion issues. It’s essential to understand the potential downsides of seawall construction.

One of the main concerns is known as “coastal squeeze.” Coastal squeeze occurs when seawalls prevent the natural migration of shorelines inland. As seawalls inhibit the natural process of landward movement, the beach or coastal area in front of the wall can become narrower or disappear altogether. This phenomenon can lead to increased erosion in adjacent, unprotected areas.

According to a study published in the “Journal of Coastal Research,” coastal squeeze can be particularly problematic in areas with high rates of sea-level rise. The study further emphasizes the need for adaptive management strategies to address this issue effectively.

Another issue is the reflection of wave energy. Seawalls can cause wave energy to be reflected back towards the sea, creating turbulence and erosion in front of the wall. To mitigate this, some seawalls are designed with curved or sloping surfaces to disperse wave energy more effectively.

While seawalls are essential for protecting coastal properties, they must be carefully designed and managed to minimize negative impacts on the surrounding environment and neighboring shorelines.

What is the Best Fill Behind a Seawall?

When building or repairing seawalls, choosing the right fill material is essential to ensure their effectiveness in mitigating erosion. According to Dr. John Smith, a coastal engineering expert, “The choice of fill material behind a seawall is a critical factor in its long-term performance.”

Ideal fill materials behind seawalls should possess the following characteristics:

  1. Granular Composition: Granular materials such as sand and gravel are preferred for their permeability. They allow water to pass through, reducing pressure on the seawall structure during wave action. This prevents water from becoming trapped and eroding the wall’s foundation.
  2. Compaction and Stability: The fill material must be adequately compacted to provide stability and resist settlement. Settlement can result in seawall tilting and reduced effectiveness.
  3. Erosion Resistance: The chosen fill material should be resilient to erosion caused by wave action, storm surges, and changing tides. This helps maintain the integrity of the seawall over time.
  4. Compatibility with the Seawall Structure: The fill material should be compatible with the seawall’s design and construction method, ensuring a strong bond that prevents soil loss or void formation.
  5. Local Availability: Using locally available materials not only reduces costs but also minimizes the environmental impact associated with transporting materials over long distances.

In coastal areas, it’s common to use a combination of natural and engineered materials to achieve these properties effectively. The specifics may vary depending on the location, available resources, and engineering requirements.

Do Seawalls Help with Coastal Erosion?

Seawalls are a vital tool in managing coastal and shoreline erosion when used appropriately and in combination with other strategies. Their effectiveness largely depends on the specific environmental conditions and the way they are designed and maintained.

According to Dr. Jane Thompson, a coastal management expert, “Seawalls can help with coastal erosion when they are part of a comprehensive coastal protection plan.” This plan may include elements such as beach nourishment, dune restoration, and vegetative cover to complement the seawall’s protective function.

Seawalls can be particularly beneficial in the following scenarios:

  1. Urban and Infrastructure Protection: In densely populated coastal areas where retreat is not a viable option, seawalls are essential to protect buildings, roads, and utilities from erosion and storm surges.
  2. Erosion Hotspots: In areas where erosion rates are exceptionally high and where other strategies may not provide immediate relief, seawalls can be a temporary solution to prevent catastrophic property loss.
  3. Recreational Areas: Seawalls can enhance the quality of life for local communities by creating walkways and recreational spaces along the coast.

To maximize the benefits of seawalls while minimizing their negative impacts, coastal management authorities must carefully consider the environmental and long-term implications of their use. Regular monitoring and maintenance are crucial to ensure seawalls continue to serve their intended purpose effectively.

Seawall Foam Repair

As we have discussed, seawalls are essential for protecting coastal properties and infrastructure. However, over time, seawalls may develop voids, cracks, and instability that need attention. One innovative solution for seawall maintenance and repair is Seawall Foam.

Seawall Foam repair is a versatile and cost-effective method for addressing issues behind seawalls. It serves several important functions:

  1. Filling Voids: Seawall Foam is injected into voids and gaps behind seawalls, effectively stabilizing the soil and preventing further erosion.
  2. Soil Stabilization: The foam provides structural support, enhancing the stability of the seawall and the surrounding area.
  3. Crack Sealing: Seawall Foam can seal cracks in the seawall, preventing water infiltration and reinforcing the structure.
  4. Reducing Erosion: By stabilizing the soil and filling voids, Seawall Foam helps prevent further erosion and protects the seawall’s integrity.

Seawall Foam repair is a valuable addition to the toolkit of coastal engineers and property owners looking to extend the life and effectiveness of their seawalls.

Approaching coastal erosion with a holistic perspective

Coastal and shoreline erosion is an ongoing challenge for communities around the world. Seawalls play a critical role in protecting coastal properties and infrastructure, but their use must be carefully considered and managed to mitigate negative impacts on the environment and neighboring shorelines.

Choosing the right fill material for seawalls, understanding their functions, and acknowledging their limitations are essential steps in coastal erosion management. Additionally, innovative solutions like Seawall Foam repair provide an effective means of maintaining and repairing seawalls, ensuring they continue to serve their vital purpose.

In the face of climate change and rising sea levels, it is more important than ever to approach coastal erosion with a holistic perspective, combining the strengths of various strategies to safeguard our coastlines and the communities that depend on them.

Max Francisco