How Groins and Revetments Help Control Coastal Erosion

20 January 2020

It’s hard to remain impartial about the whole global warming debate when we see our coasts being borne away by tidal forces. The sands shift, are absconded by the sea, and a landmass shrinks. Coastlines are actually changing shape and retreating because of this phenomenon. To address the matter, to protect a nation’s shores, technical services reps are currently developing a whole arsenal of augmented coastal erosion solutions.

Preparing Coastal Erosion Defense Solutions

Just like most of nature’s forces, the waves that strike our shores are packed full of dynamic energies. When the wind attacks a tall building, it strikes from different directions, then the strength drops before increasing again until a gale-force howl slaps the superstructure. Well, tidal forces are much the same, unfortunately. That’s why engineers concern themselves with diurnal tides and wave heights. Level fluctuations and wind-generated current surges affect their plans as well. Otherwise, a formidable wave breaking structure wouldn’t provide much help, not when an annual surge could sweep a white-crested wave over its face.

Understanding Groins and Revetments

Let’s talk about erosion control. There’s more to this field of study than seawalls. Granted, structures provide intervening barriers, and those barriers stop waves from scooping sediment out and away from the shore, but they rarely work alone. For instance, away from the shore, there’s probably a structural breakwater out there. It saps power from the tide. Back onshore, engineering consultants prepare the next line of defence. Here’s where revetments enter. Composed of stacks of boulders, the erosion impeding barrier performs as a kind of natural wall. It even looks like a naturally occurring shore buffer, when it’s actually been put together by a team of construction workers. Groins are a little different. They work at right-angles to a beach. They can be seen jutting outwards from a beach and into the water as a long projection of rubble, timber, or steel pilings. As for their functions, shore “groins” basically perform as sediment collection mechanisms.

There’s no such thing as a simple seawall anymore. There are benched walls and angled walls, which utilize rock toe protection installations and wave screen crowns. It’s the same with groins and revetments, too. Different materials and bank patterns are used to trap sediment in sawtooth-like formations, at least that’s the general principle that stands behind groin design. Revetments are equally intricately designed. Cast-concrete boundaries marry up with rocky rick rap barriers to minimize the effects of coastal erosion, then there are interlocking blocks to install when the calculated wavelengths and peaks of a diurnal tidal zenith threaten to overwhelm a structure’s defences.

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