The coastal zone is used for fishing, transportation, recreation, waste disposal, cooling and drinking water and is potentially a source of energy from tidal and wave power. Many of these activities pose an environmental threat to coastal systems, both physical and biological, through pollution, siltation, dredging, infilling and a host of other activities that alter the way natural systems operate (Masselink and Hughes 2003). Ironically, armor is supposed to be a protection factor when in fact, it can have both ecological and recreational consequences. An armored section of shoreline may be protected for a little while, but this structure can actually increase the erosion on the beach itself. This happens because the structures are there
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They are built to withstand: local climate, waves, and the position of the coast. Because they to face a variety of environmental problems, they are considered hard engineering because they provide a protection from coastal erosion, but it comes at a high price, always having to maintain and fix. Three main types of seawalls are: vertical, curved, and mound. A vertical is the easiest wall to construct. (figure 2) It deflects a wave's energy from the coast, but has a high cost in damage in a short period of time. A curved wall (figure 3), also known as stepped seawalls, takes the break of the wave and repels the energy of the wave back to the sea. Because it is curved, the top of the wall is protected since it prevents the wave from overtopping the wall. Lastly, the mound wall are used in environments in less demanding areas (figure 4). This wall is the lowest costing due to it being built by sandbags, and rocks. This armor of the wall is porous, which allows little water to flow through even after the wave has broken. It is the lowest costing wall and would not be able to withstand high-energy conditions very well. China is discovering that within the next 100 years, the sea level will rise to approximately 50 cm higher than it is today (Feng 2009). This is a major issue considering most of the world’s major cities are located in coastal zones. Global sea level rise is going to become a major risk for these populations. The other underlying issue is, there is three major spatial forms of coastal erosion. Two of them have a positive and negative affect with seawalls. One form, coastal retreat, needs the protection measures of seawall engineering. The other form, landward movement, usually occurs from a coast with a
They are built to withstand: local climate, waves, and the position of the coast. Because they to face a variety of environmental problems, they are considered hard engineering because they provide a protection from coastal erosion, but it comes at a high price, always having to maintain and fix. Three main types of seawalls are: vertical, curved, and mound. A vertical is the easiest wall to construct. (figure 2) It deflects a wave's energy from the coast, but has a high cost in damage in a short period of time. A curved wall (figure 3), also known as stepped seawalls, takes the break of the wave and repels the energy of the wave back to the sea. Because it is curved, the top of the wall is protected since it prevents the wave from overtopping the wall. Lastly, the mound wall are used in environments in less demanding areas (figure 4). This wall is the lowest costing due to it being built by sandbags, and rocks. This armor of the wall is porous, which allows little water to flow through even after the wave has broken. It is the lowest costing wall and would not be able to withstand high-energy conditions very well. China is discovering that within the next 100 years, the sea level will rise to approximately 50 cm higher than it is today (Feng 2009). This is a major issue considering most of the world’s major cities are located in coastal zones. Global sea level rise is going to become a major risk for these populations. The other underlying issue is, there is three major spatial forms of coastal erosion. Two of them have a positive and negative affect with seawalls. One form, coastal retreat, needs the protection measures of seawall engineering. The other form, landward movement, usually occurs from a coast with a