In December 2013, a massive tidal surge flooded 1,400 homes along the east coast of the U.K., which has managed to destroy and tumble some of these houses into the Atlantic Ocean. Over the next century, it is estimated that estates worth over 1 billion pounds will be lost due to the effects of coastal erosion. And within the next 20 years, over 800 estates will be lost. Coastal erosion is the reduction of material attached to the coastline by various natural or man led activities; coastal erosion leads to the landward retreat of the coast. Coastal erosion endangers coastal city’s livelihood and source of income thus, defending it through efficient means is important as it stabilizes the lives of the people who live near the coast. To efficiently fight coastal erosion a methodical combination of engineering and non-engineering solutions must be utilized. This essay will firstly discuss the hard engineering solutions that could be used in coastal defense and then continue to the soft engineering solutions and the theory of how both methods can be utilized. This essay will also be primarily limited to Western nations. Therefore, the economic and educational prospects could substantially differ from other countries.
Hard Engineering
Rather than relying on natural means in defending the coast from erosion, utilizing human engineering into constructing hard structures could be a course of action. Seawalls are long-term hard structures often built to reduce coastal risks to infrastructure and life where the natural beaches have been eliminated or significantly restricted and where other risk reduction options are prevented by lack of space or sediment. Seawalls are often curved to redirect wave energy back into the sea or ocean. Moreover, seawalls are also intended to hold the shoreline position by weakening storm surges and high energy wave attacks. Sea walls cost between 0.6 and 44 million dollars per mile to build depending on construction material, the height of the design and wave loadings. For example, Galveston Seawall has protected Galveston against numerous hurricanes, and it is estimated that if the seawall were not to be in place, it would have cost the relevant authorities $234 million due to the damages made by a single hurricane. Furthermore, as these curved seawalls redirect wave energy back into the sea or ocean their base is slowly eroded, thus requiring constant expensive maintenance which discourages investment. Seawalls may also lead to the transportation of sand away from the beach and into the sea which would result in the acceleration of beach erosion. To counter the unwanted erosion seawalls can be situated to retain, restore, or add natural, semi-natural, or artificial landforms and habitats. Seawalls may be altered to assist the habitat by providing better surface complexity, for example, building rip-rap revetments (uniquely shaped boulders usually made out of concrete) rather than vertical walls have been shown to reduce the negative environmental impacts. Overall, seawalls are a long-term and effective yet expensive mean to protect against natural disasters that emanate from the sea. However, they may lead to negative long-term environmental impacts such as accelerating the beach erosion process.
Furthermore, another hard engineering method that is utilized to protect against coastal erosion is groynes. Groynes are dam-like structures built into the shore with the purpose of blocking sediments from drifting away. Therefore, they provide their benefit to the beach by trapping and holding sand and sediments in the desired location and allowing proper (read: adequate) enough elevation to be maintained. The fundamental objective of groynes is to reduce the rate of sediment loss in the project area thus reducing damages done by erosion. The beach occupied by the structures provides protection to the back beach and human development. This approach is appropriate in areas suffering from long-term erosion due to diminished sediment supply. However, as the sediments accumulate on the updrift side of the groyne, the beach widens but occasionally, the adjacent downdrift beach erodes at an accelerated rate. The accelerated erosion downdrift from a groyne can be highly problematic and makes it a highly incompetent measure to protect against coastal erosion. Furthermore, as the Bethany Beach case study will show later on in the essay, groynes are inefficient if left alone and not regularly maintained with proper maintenance tools thus, making this approach relatively expensive.