Summer is here! To escape the summer heat, people worldwide flock to the sea and its beaches.
This is why many corporate projects and tourist resorts have always grown up along the coasts.
But have you ever considered what would happen if the ocean decided to erode these beaches and destroy all of these built-up areas?
You might wonder why this could happen. And, if so, how can we protect ourselves from such a scenario?
What types of coasts do we have?
Having a deep background of the situation will help you to figure out an effective solution.
Cliff coast
The Cliff coast is considered a “hard” coast since it was formed by difficult components such as sedimentary or volcanic rocks.
This type of coast is distinguished by a short beach platform that is exposed during low tide.
Natural erosion is caused by slope instability, weathering, and wave action and results in coastline regression.
The clayey bank coast
This is a “semi-hard” coast composed of cohesive soils; it is widespread on estuary beaches and frequently has virtually vertical banks ranging in height from one to five meters.
Because it is made of weaker and less resistant material than the hard coast, the rate of erosion is rather high.
Erosion is caused primarily by coastal processes, weathering, ammeters the removal of plant cover.
Muddy/intertidal coast
This shoreline is distinguished by fine-grained sedimentary deposits, primarily silt and clay from rivers.
The majority of erosion is caused by river damming, which limits sediment supply, reduces plant cover (typically mangroves and salt marshes) and exposes vegetation roots by lowering the mudflat flat, resulting in their eventual collapse.
The coast of dunes
This sort of coast is made up of unconsolidated material, primarily sand, with some pebbles and shells thrown in for good measure. It has a mild seaward slope.
This sort of shoreline exhibits cyclic erosion or short-term fluctuation accretion and long-term evaluation is required to identify erosion as a concern here.
A decreased beach face slope and the lack of a near-shore bar, berm, and erosional.
Sandy coast
Unconsolidated material makes up this sort of shoreline, broken coral branches and shells from bordering reefs.
It is characterized as a soft coast with offshore reef protection.
Most erosion is caused by the loss of coastal habitat’s protective role, particularly coral reefs (where they are located) that protect the coast from wave action and coastal trees that shelter the coast from high winds.
Why does coastal erosion happen?
Coastal erosion is commonly caused by the action of waves and currents.
It can also be caused by mass wasting processes on slopes and subsidence.
Significant episodes of coastal erosion are frequently associated with extreme weather events (coastal storms, surges and flooding), but also with tsunamis.
Both because the waves and currents are more intense and because the associated storm surge or tsunami inundation can allow waves and currents to attack landforms that are normally out of reach.
Such processes can cause cliffs and steep slopes on coastal headlands to be undercut, contributing to mass waste.
Furthermore, excessive rainfall can increase soil saturation, with high saturation resulting in a decrease in shear strength and an increase in the likelihood of slope failure (landslides).
Coastal erosion is a natural phenomenon that happens when the transfer of material away from the coastline is not balanced by the deposit of fresh material onto the beach.
Many coastal landforms experience quasi-periodic cycles of erosion and accretion over periods spans ranging from days to years.
This is notably noticeable on sandy landforms such as beaches, dunes, and lagoon openings that are intermittently closed and open.
However, human activities can have a significant impact on the susceptibility of landforms to erode.
Construction of coastal constructions, for example, such as breakwaters, groins and seawalls, can alter coastal sediment transport routes, resulting in erosion in some regions and accretion in others.
Unintended erosion can also be caused by the removal of sediments from the coastal system (e.g., by dredging or sand mining) or a reduction in the supply of sediments (e.g., by river management).
At broader scales, both natural and anthropogenic climate change can influence the likelihood and pace of coastal erosion.
Why coastal erosion is a problem?
Coastal erosion causes several problems for coastal towns, including the loss of valuable real estate and personal property, recreational areas and critical natural flood protection.
Coastal communities are concerned about the best ways for managing beach erosion and recover land.
Human activities, particularly bad land-use uses practices, may exacerbate coastal erosion.
Built buildings, for example, that do not take into account coastal erosion cycles or hydrodynamics might exacerbate erosion or move sediments to surround locations.
Some coastal-control buildings are created along the shore to prevent erosion in a specific spot; but, if not appropriately built, these structures can exacerbate erosion in surrounding locations.
Ways to protect against coastal erosion
different strategies have been utilized in various locations to avoid beach erosion.
Some of these strategies have shown to be effective, but each has its own set of downsides and benefits.
The following are some of the most frequent ways for preventing coastal erosion:
Groins
These are lengthy, wall-like constructions that are created on beaches and run perpendicular to the coastline into the water.
Groins are designed to function as a barrier to longshore currents.
This enables them to regulate and adjust the sand movement.
Jetties
This approach entails building a line of long buildings perpendicular to the coast that stretch into the ocean (two or more depending on the number of channels).
These are often made of stone, concrete, steel, or wood and are used to keep sand out of a ship canal.
As sand accumulates against the jetties on the up-current side, it can be moved down the beach to help decrease erosion.
Breakwaters
These are obstacles built offshore that run parallel to or at an angle to the shoreline.
Breakwaters serve as a wave barrier, allowing the beach to expand while preventing damaging erosion.
When waves hit the breakwater, they deposit silt along with it.
These are often made of stone, concrete, steel, or wood and are used to keep sand out of a ship canal.
Beach nourishment
This is a soft approach (no hard construction required) that includes placing sand on the beach to artificially enlarge it.
Although this method has the potential to be beneficial, it is both expensive and impermanent.
Vegetation
Strategic planting of vegetation can aid in erosion control.
The roots of coastal plants assist to anchor the sand and keep it from being washed away during erosion.
To minimize erosion, several locations plant seagrass and develop marshes along coastlines.
Seawalls
Seawalls are a very efficient method of erosion prevention.
These are buildings created along the beach to prevent waves from ever colliding with the sand/shore on the other side.
While seawalls are highly successful at stopping erosion, they can only defend the shoreline along which they are erected.
References
1- CHAPTER 4 PROTECTION FROM COASTAL EROSION [online] Available at: https://www.fao.org/3/ag127e/ag127e09.htm
2- Coastal Erosion [online] Available at: Coastal Erosion | Geoscience Australia (ga.gov.au)
3- COASTAL EROSION [online] Available at Coastal Erosion – What is the hazard? – NYC Hazard Mitigation
4- WAYS TO PREVENT BEACH EROSION [online] Available at Ways to Prevent Beach Erosion | Seawall Professionals of Florida (seawallprosfl.com)
