Seawalls also known as revetments are shore-parallel structures at the transition between the sandy beach and the mainland or dune. The height of a seawall often fills the total height difference between beach and surface level of the shore. In most cases adjacent at the crest of a seawall a horizontal stone covered part is present (for example, Boulevard; road; or parking places). At the initial time of construction, a seawall is situated close to the position of the dune or mainland foot.
Furthermore, revetments are another shore parallel structure. The main difference between a revetment and a seawall is that it a revetment is more sloping than a seawall. A revetment has a distinct slope whereas a seawall is often almost vertical. The surface of a revetment can either be smooth or rough while a seawall is mostly smooth. The height of a revetment does not necessarily fill the total height difference between beach and mainland unlike a seawall often covers the entire height difference. Revetments and seawalls are very similar regarding their characteristics. We shall see more consideration on each of these below.
Seawalls
A seawall has a good number of characteristics with other marine construction structures. Most times, all marine structures are considered as seawalls. However, experts understand that this may not be the full truth as some slight differences between each. Seawalls are also the most popular kind of marine construction structures. A seawall and a bulkhead can look identical when looked at without any instrument or proper precaution. Like a bulkhead, a seawall retains earth on one side of the wall and has water on the opposite side. However, the difference between and a bulkhead are its functional capabilities. Aside from holding soil in place, a seawall also protects property from wave action. Seawalls are designed to hold off the constant impact of waves hitting them and periodic occasions of significant pressure caused by more massive storm surges (hurricanes).
Revetments
Revetments are primarily constructed of rocks or other materials which are durable to protect designated slopes. They are built with an armored layer, toe protection as well as filter layers. The armored layer can consist of interlocking structural elements designed to form a geometric pattern, or random mass or stone. A filter layer ensures drainage and protection of the underlying soil. The toe protection functions as stability against undermining at the base of the revetment. Revetment armor may be rigid or flexible, as seen with concrete slabs-on-grade or riprap and quarry stone respectively. Rigid armors in a revetment are more massive but are not able to accommodate settlement and adjustment, and they have less strength than flexible armors.
Revetments typically appear differently from other marine construction structures like retaining walls, bulkheads, and seawalls. A revetment has a sloped appearance instead of the conventional perpendicular appearance of the other marine structures. However, the most significant difference is the primary function it serves, to slow or help prevent erosion. 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.
