Coastal erosion is a major issue that affects coastlines across the globe. It is the gradual wearing away of land caused by natural forces such as waves, wind, and tides. The effects of coastal erosion can be severe, leading to loss of property, destruction of infrastructure, and environmental damage.

At Armstrongs, we contribute to combating these effects by supplying rock armour for coastal protection projects. Our rock armour helps prevent further erosion and safeguard coastlines for future generations.

In this guide, we’ll be taking a look at the types of coastal erosion and prevention methods available.

What is Coastal Erosion?

Coastal erosion refers to the natural process where the land along coastlines is gradually worn down by external forces such as waves, wind, and tidal action. Over time, these forces strip away layers of soil, rock, and sand, reshaping coastlines and causing them to retreat.

The effects of coastal erosion can be devastating, impacting not only the environment but also coastal communities and infrastructure.

Loss of land and destruction of roads, homes, and businesses are common outcomes, making it essential to implement strategies to mitigate the impact of coastal erosion.

Types of Coastal Erosion

Hydraulic Action

Hydraulic action is a process where powerful waves crash against the coastline, forcing water and air into cracks within the rocks.

The trapped air compresses, exerting pressure on the rock, and as the waves retreat, the air expands, causing the rock to fracture and break apart.

Over time, this continuous cycle contributes to significant erosion, particularly along rocky coastlines.

Abrasion (Corrasion)

Abrasion occurs when rocks, pebbles, and sediment carried by waves grind against the shoreline, effectively “sanding” down the coastal rock and cliffs.

This is one of the most aggressive types of erosion, and it often leads to the rapid breakdown of coastal landscapes, contributing to the formation of cliffs, caves, and other coastal features.

Attrition

Attrition refers to the process by which rocks and pebbles within the water collide and grind against one another, gradually wearing down into smaller, smoother fragments.

This process results in sediment that further contributes to the erosion of the coastline as it is carried by the waves.

Solution (Corrosion)

Solution, also known as corrosion, involves the chemical reaction between seawater and certain types of rock, particularly limestone and chalk. 

The acidic nature of seawater causes these rocks to dissolve over time, leading to the gradual retreat of the coastline. This process can have significant long-term effects on coastlines composed of susceptible rock formations.

Effects of Coastal Erosion

Impact on Communities and Infrastructure

The effects of coastal erosion are not only environmental but also social and economic. Communities living near eroding coastlines are often forced to relocate as their homes and businesses are threatened or destroyed.

Roads, utilities, and other essential infrastructure can also be severely impacted, requiring costly repairs or complete reconstruction. Coastal communities reliant on tourism may experience a decline in visitors due to deteriorating landscapes.

Environmental Consequences

Coastal erosion significantly impacts local ecosystems and habitats. The destruction of wetlands, dunes, and other coastal habitats leads to loss of biodiversity and destabilisation of ecosystems.

Species that rely on specific coastal environments for survival, such as birds and marine animals, face habitat loss, leading to a decline in populations. Moreover, sediment from eroded coastlines can negatively affect nearby marine environments, disrupting coral reefs and seagrass beds.

Coastal Erosion Prevention Methods

Hard Engineering Solutions

Rock Armour (Rip Rap)

One of the most effective solutions for coastal erosion is the use of rock armour. Large boulders are strategically placed along vulnerable coastlines to absorb and deflect the energy of incoming waves.

This reduces the direct impact on the shoreline, minimising erosion. At Armstrongs, we have experience in supplying rock armour for coastal management projects. Our high-quality stone is sourced from our quarries and used in major coastal defence schemes, ensuring long-term protection for the coastlines.

Sea Walls

Sea walls are another solution for coastal erosion. These man-made barriers are built along the shore to reflect wave energy away from the coastline.

Although effective, sea walls can be more expensive to construct and maintain than natural solutions like rock armour. They can also have environmental impacts by disrupting natural coastal processes.

Soft Engineering Solutions

Soft engineering solutions focus on working with natural processes to protect coastlines. Beach nourishment involves adding sand to eroded beaches to replace lost sediment, while dune stabilisation strengthens dunes to act as natural barriers against coastal erosion. These methods are often less invasive but may require more frequent maintenance.

How to Choose the Right Erosion Prevention Method

Assessing Coastal Needs

Choosing the right method to prevent coastal erosion depends on several factors, including the level of erosion risk, the environmental impact, and the available budget. Rock armour is an ideal choice for coastlines experiencing high-energy waves and severe erosion.

Its durability, low maintenance, and ability to blend with the natural landscape make it one of the most effective solutions in coastal management. However, softer approaches like beach nourishment may be more appropriate in areas with lower energy wave action and less severe erosion.

Armstrongs’ Role in Coastal Protection

At Armstrongs, we provide high-quality rock armour sourced from our quarries across the North West and Cumbria. Our rock armour has been used in major coastal defence projects, including the Wyre Council Rossall Coastal Defence Scheme.

We are dedicated to supplying durable, sustainable materials that help protect coastlines from erosion and flooding. Our experience in coastal protection ensures that the stone we provide meets the highest standards, offering long-lasting solutions for vulnerable coastlines.

FAQs about Coastal Erosion and Prevention

What is coastal erosion?

Coastal erosion is the process of land along coastlines being worn away by natural forces such as waves, wind, and tides.

What are the types of coastal erosion?

The main types of coastal erosion include hydraulic action, abrasion, attrition, and solution.

How does rock armour protect the coastline?

Rock armour absorbs and reflects wave energy, preventing erosion and protecting the coast from the damaging forces of the sea.

What are the most effective methods to prevent coastal erosion?

Common prevention methods include rock armour, sea walls, and soft engineering techniques like beach nourishment and dune stabilisation.

How can Armstrongs help with coastal protection projects?

Armstrongs supply high-quality rock armour for coastal defence schemes, offering durable, sustainable solutions to protect coastlines from erosion and flooding.