Shoreline Erosion: problems and solutions
Isabelle Crampton
Over the years, shorelines across the world have been eroding and receding dramatically. While this is a natural process, it is greatly accelerated by human interaction with the environment, which causes a multitude of negative impacts including the submergence of occupied land and the disturbance of animals’ habitats. This makes shoreline erosion an important issue for mankind to assess. Specific and direct causes that lead to shoreline erosion include: failed government projects, boat wakes, storm surges, and engineered “solutions’’.
Protecting shorelines has been attempted by the U.S. government, but has mostly failed. Projects have been started, but most have fallen through because of lack of funding or interest. Another problem with federally funded environmental projects is that there is no clear goal. Most federally funded projects, specifically ones exploring shoreline erosion, don’t follow through, causing a lack of knowledge among scientists and the general population.
Where the government fails most is allowing the development of hardscapes, buildings, and roads close to shorelines, even though halting these developments is easy to enforce. . One third of the human population lives within population 100 kilometers of the coast. Additionally, half of the world’s population lives within 200 kilometers of the coast . This many people living within a couple miles of a shoreline causes significant damage to the natural habitats of animals. People are also at risk through exposure to the elements, flooding, tsunamis, and other forces of nature. Harmful human activities that take place near coasts include: commercial fishing, tourism, and recreational activities.
Boat traffic harms many parts of our ecosystems. Loud motors cause noise disturbance to wildlife like osprey, which come back to the same nesting spot for generations; big waves can cause fish to be separated from their groups; seagrasses and marshes become structurally unsound; snails can be knocked off their grasses and eaten; bigger and repeated waves cause damage to shorelines.
One of the most preventable and arguably the most detrimental human acceleration of shoreline erosion is boat wakes. Boat wakes cause waves that repeatedly hit the shoreline, causing it to recede and erode by direct impact. Boat wakes are more harmful to shorelines than regular waves because when a boat wake crosses paths with a natural wave, the combination causes the waves to amplify in magnitude. Typically, vessels within 150 meters of a shoreline can cause a detrimental wake. These wakes are already troubling, but they cause even more destruction when boats go through a narrow channel, because the waves can bounce from shore to shore. By having “No Wake” signs posted in vulnerable places and allowing less boat traffic to travel through narrower channels, shoreline erosion that is accelerated by boat wakes can greatly be reduced.
Storm surges are another way in which a wave erodes the shorelines. A storm surge is an abnormal rise in water height during a storm, ultimately caused by the rise in water levels due to global warming. This causes shorelines to recede due to repeated physical impact from bigger waves. To combat eroding shorelines caused by storm surges, sand is taken from previously dredged areas, nourishment is added to it, and it is placed on the beach so that the new shoreline extends higher and further toward the sea. The added nourishment is good for some aspects of the ecosystem, but bad for other parts. According to an article published in Bioscience“…[H]abitats are substantially disturbed by and can be functionally degraded through the process of nourishment” (Peterson, Bishop). Unfortunately, storm surges are an unavoidable and untreatable aspect of climate change; however, how the damage is prevented is in humanity’s hands.
Shoreline hardening devices can be placed to prevent erosion, but most devices have negative impacts on different environmental issues. For example, seawalls are placed so that damaging waves can’t reach the shoreline, but they are tall and flat, meaning there are no crevices for marine life to settle and develop.
Most engineered solutions do more harm than good; they treat erosion, but cause a different issue, like seawalls do. One engineered solution that has shown promising results thus far is called a “living shoreline.” One example of a living shoreline is placing concrete pyramids along the shoreline. These pyramids break the waves so the impact to the shoreline is smaller, and they promote biodiversity by providing space for marine life to grow. The living shoreline has shown to be better for marine life than a similar solution called “ripraps”, which are piles of rocks that break waves, but reflect sunlight into the water, causing the natural water temperature to rise. According to the Federal Emergency Management Agency (FEMA), Living shorelines are more structurally sound than ripraps.. The main reason why living shorelines and other shoreline-protecting devices aren’t used more often is because they can be prohibitive for the average homeowner.
In the future, engineers hope to invent more sustainable, environmentally friendly, and cheaper tools to manage shoreline erosion. Some ideas listed by FEMA include bioengineering, hydroseeding, “controlled planting and the construction of engineered logjams”.
Shoreline erosion is a natural process, but it is greatly accelerated by human interactions with the environment. Federally funded projects are not very reliable because shoreline erosion is not considered as important of an issue compared to others. Some argue that since shoreline erosion is a natural process, it should be left alone, while others argue that there is nothing ‘natural’ about human acceleration of the problem. There have been some promising structures placed on coasts that protect the shoreline while simultaneously promoting marine growth, such as oysters.
Engineers are also looking into more marine-friendly structures that are even better than the latter. Shoreline erosion is just one, multi-faceted way that climate change is affecting humanity daily, and it can hopefully be dealt with properly if citizens are given the right education and have the right amount of care for the environment.
Isabelle Crampton is a member of the Science Research team in VAYCC
