The oceans are currently constantly rising; this means that the water level will naturally have to look elsewhere to get accommodation for its added water. This is a natural process as we’ve rightly said, but the consequences to our surroundings could be disastrous if we do not manage it. Coastal areas are encouraged to build-up resistant structures to the strong force of the ocean. And such strong forces need to be managed to stifle the erosion of the land area along the coast. The best structure which can help against coastal erosion is the revetment. Before its use in the coastal areas to prevent erosion, it is essential to note that it was once widely used on the battlefield to protect against enemy fire. However, in the present day, revetments are made for coastal protection.
A revetment is a structure that is designed to protect the shore area from gradual erosion from seawater bashing. It is mostly used in areas where the coastline is vulnerable to the flow of the sea. Revetments have been in extensive usage in other areas. This structure is also used for the protection of residential buildings that happen to be built along the vulnerable coastline. There are different types of revetments, and each type has its specific functions that differentiate them from one another.
In stream restoration, river engineering or coastal engineering, revetments are sloping structures placed on banks or cliffs in such a way as to absorb the energy of incoming water. In military engineering they are structures, again sloped, formed to secure an area from artillery, bombing, or stored explosives
A revetment wall is a sturdy barricade made for the sole purpose of deterring the ocean flow from causing damage to the landmass bordering it. Revetment walls are typically made from very durable, highly-dense materials which ensure that it stands the test of time against the forces of nature. A revetment wall usually is built around coastal locations where the water levels have almost completely erased the surrounding shoreline. This structure is a feat of hard engineering and is designed to prevent further erosion from taking place
Uses of Revetments
We’ve seen from the discussion above that revetments are very useful for coastline defense. This is a significant feature in coastline preservation and other vital functions. Revetments are used for a variety of reasons, and some of these reasons are identified below;
· Land protection:
The use of revetments makes it possible for the landmass to be adequately protected from being gradually washed away into the surrounding waters. This keeps the land bordering the waves from the sea intact to a high degree. Revetments are made of different materials depending on the strength of the waves toward the area, but they are most effective in staving off the force from the waters.
· Wake waves repellent:
The wake waves we’re referring to are the waves which form as a result of ship activity on the sea. The use of revetments along the banks of waters efficiently beats back this artificial flow of waves toward the shoreline. Wake waves may not be frequent in occurrence, but the continuous force it carries to land whenever a vessel passes by gradually washes off the land area. This is why the use of revetments along land areas bordering the waterways is so necessary.
· Coastal Land Preservation:
The revetment is built along the affected coastline to keep the land vulnerable to sea action from further damage. This means that the coastal land areas which are supported by these solid structures are now preserved from further degradation. The revetment is very efficient in this regard as it can withstand the force of waves for an extended period.
· Flood Prevention:
Revetments are made to withstand some of the impacts from flooding or reduce its effects around the surrounding land area it protects from crashing sea waves. They act as a buffer in times of low-level flooding and reduce the impact on the shoreline population and infrastructure. It is possible for revetments to combat flooding because of its peculiar design. They are not built as walls but as sloping structures that allow some level of water movement. This keeps the transportation of seawater intact while still retaining the integrity of the surrounding land area.
Lifespan of Revetments
The lifespan of revetments usually depends on the way it’s structured. The most popular types of revetments in extensive use throughout the world today are rubble and tetrapod revetments. These structures can last up to more than half-a-decade. This shows that the revetment structure is one very durable engineering structure meant for the protection of the shoreline.
Advantages of Revetments
· Wave Absorbent:
The permeable revetment is built in a different form and acts more effectively against erosion than a seawall. The revetment is constructed to contain slats through which the hard waves of water can flow through and return to the ocean. This is a means of absorbing the otherwise destructive wave force from eroding the shoreline. This structure is most efficient against limiting the strength of damaging waves.
The revetment structure can last for many decades. In the old days, wooden revetments were in extensive usage but have been rapidly replaced by more modern, concrete designs. The wooden revetment was subject to becoming unsuitable for defending the coastline after a short period, as the wood may lose its integrity from receiving continuous bashing from the sea.
Cost of Revetments
There are different types of revetments, and these structures are used depending on the force of the coastal waves. The cost of revetments also differ; there are some which are low-cost, while some others may cause a head-scratching moment for the builders. Wooden revetments are naturally cheaper as they require little engineering work, and the materials are easy to source. Impermeable/Permeable structures which are made from solid concrete and rest on the coastline for a wide area may cost a few million pounds for about five thousand revetments for the permeable revetments, or a specified distance for the impermeable type. Also, rock revetments may cost up to 3 million pounds for the installation of up to three thousand revetment structures.