What are sea walls?

Sea walls are a form of hard engineering coastal protection. A man made wall structures built on or near the shoreline with the purpose of absorbing storm wave energy to protect the land or an area of water behind the wall from erosion. However, a seawall may not protect a coast from erosion in the long run. As waves break against the seawalls, the energy from the waves is redirected downwards, to the base of the seawall, causing it to weaken and eventually collapse. Hence, seawalls have to be carefully maintained. It is also expensive to build seawalls. In England it can cost $3 million to build a one kilometre stretch of seawall.

Whoop de-do it costs so much more in Australia! For a wall 100m long it costs over $400 000AUS. The thing with some rock and sea walls is that they can also be built on the beach to raise residential and commercial housing as the early quote stated to protect them. Unfortunately with this strategy the sand needs replenishing and this costs in the millions to support vasts projects like this.