A Tidbit about Coastal Erosions

If you built a sandcastle too close to the shore, there likely won’t be one as soon as a wave hits it. Even if by some miracle it had survived, it’s pretty much vulnerable for another wave, then another, until your sandcastle is nothing more than a moist lump of sand. You could say that the sandcastle’s structure eventually degraded – or eroded, losing to the merciless ocean tide, making you wish that you had attempted making your building a little bit farther away.

Erosion, in a general sense, isn’t as sudden or quick to destroy a structure. Its effects are best witnessed over a lengthy course of time. However, by seeing a “before” and “after” comparison of a location facing erosion, you would notice a significant difference between the two.

Not to dive into a full-blown definition, erosion is a gradual process of a structure being chipped away from constant elements like water or wind. The term has an assortment of meanings behind it (both in the literal and metaphorical sense), but this piece will lean on the former – particularly on coastal erosions, the slow and steady damages they inflict on society’s structural borders, the dangers of disregarding these instances, and of the steps that are being taken to mitigate their impact.

When natural barriers like coastlines take the brunt of such erosions, what happens is that the water flow repeatedly crashes into a portion of the structure (thus chipping at it) and carries off whatever component that eventually breaks from it. These break-off components may be deposited somewhere nearby, or be carried to somewhere as far as another country, depending on the water flow and the environmental factors in the vicinity. Even the Grand Canyon itself underwent a series of erosions at one point – being carved by networks of waterways as one among many factors – over millions of years to become the wonder of the world it is today. No matter how sturdy, immovable, and seemingly immaculate the structure, it will eventually break under persistent forces.

Erosions are like warning signs reminding the residents that a better defense is needed against the worse possibilities that may sweep in eventually. A neglected barrier (natural or artificial) that had already suffered some damages from erosions may not be sufficient to repel any potential sea swells and tidal waves, let alone a tsunami. This is especially a life-or-death situation for communities living in low-laying nations, where something as avoidable as sea swells can end up overflowing the coastal barriers and flooding the roads and even homes in the area. If the massive deluge ends up filling up the sewage system, not only it would be unavailable to take in water from potential rainfalls, but will also back up the sewage system and send all sorts of nasties out in the open. The last thing you would want is to wade through a river of filth on your way to work.

Erosions don’t always stem from the sea. Constant rainfall can also pose its own kind of damage via structural degradation. For areas that have a lot of steep structures such as hills and mountains, runoff water can loosen the soil and cause landslides – which can even pack a bigger punch in damaging households, vehicles, livelihoods, and even lives. Pairing this with coastal erosions makes this a two-pronged attack on the vulnerable nation – a case that is worsening in tandem with the effects of climate change.

As mentioned in a previous article, putting up sandbags at your doorstep can be a quick approach to prevent indoor flooding, but that solution is temporary. Setting up a proper wall between a territory and the ocean it is surrounded with is the surefire way in preventing excess seawater from seeping into the roads and homes of the community. That’s why coastal engineering – such as the implementation of breakwaters – is helpful.

As the name sort of implies, breakwaters can severely lessen or even completely halt the impact of the incoming water flow by breaking its pace into smaller sections. What initially starts as a major wave might reach our coastline as mere splashes of seawater. This can be attributed because of the structure of the breakwaters themselves since they have a couple of different variations on how they are built. Take the fancy tetrapods, for example, found in many parts of the world (especially Japan, where nearly half of its 35,000km coastline is filled with those or similar structures). Their tripod-like structure makes it better capable of dissipating the force of an incoming wave, but it also serves as a nice habitat for some sea creatures such as crabs, and even as a nice spot for some land-dwellers such as cats.

While these structures are mostly artificially made – as are steel-based breakwaters, they were built with the intent of longevity and resilience in mind, although the end result doesn’t always turn out that way. They would still be prone to breaking off at some point. Of course, making and setting these up could also become a physical and financial hassle, but what if there was a simpler alternative?

There is, actually. Mangroves may not be considered to some as a breakwater by definition, but they do play a part of one, along with a couple of more functions that actual breakwaters cannot do. While artificial breakwaters are structurally idle, mangroves can take advantage of the incoming attack and become even more resilient over time through growth – perhaps in a “what doesn’t kill you makes you stronger” kind of way. Additionally, as they play the frontline defense role against the tides, they also play a fostering role for the underwater ecosystem, housing a hospitable environment for marine life.

And finally, they’re plants – definitely a much-needed help in our current struggle against climate change. Being a prime example of a “blue carbon” storage system, global carbon storage by mangrove ecosystems can be estimated at 34 million metric tons per year, according to a 2017 publication from Frontiers in Ecology and the Environment.

Now for a “bad news, good news” moment. Despite their value in carbon sequestration along with their defense mechanism against tides, mangroves are also facing the threat of industrialization – being wiped out for the sake of expanding human lifestyles. The good news, however, comes from emphasizing the said value of these biomes. Efforts are being intensified in the proliferation of mangroves throughout the globe. This doesn’t mean that one shouldn’t get rid of artificial coastal engineering altogether – it’s just that it never hurts to receive a helping hand.

Anyway, that’s the gist of a not-so-in-depth tidbit about erosions in a nutshell. What you should take from all this is that erosions may appear at constant nips at a well-reinforced structure, but looks can be deceiving. Once erosion destroys one layer of defense, it won’t hesitate to chip away at the next layer. The sandcastle is perhaps the aptest metaphor for the occasion.