The Search for the Perfect Solution to Coastal Erosion

In recent years, the atmosphere has been getting warmer at an alarming rate due to the emissions machines are creating. These warmer temperatures melt the ice caps, leading to a rise in sea levels. In many countries, land development on mangroves has led to the destruction of natural barriers that protect from the power of the ocean. Coastal cities are now in threat of being flooded by the ocean, causing millions to lose their homes around the world. For example, in Los Angeles, the ocean slowly encroaches upon beachfront houses. While solving climate change would be the most effective way to stop coastal erosion, this is unrealistic because the whole world would have to control large corporations to reduce their emissions. A temporary solution tailored to the specific region of the world has to be created in order to slow down the effects of the rise in sea levels. These solutions include hard barriers, like seawalls, or soft barriers, like living shorelines. A seawall is a hard concrete wall that blocks the coast from waves. One of the downsides to a hard structure is that they reflect the waves to neighboring beaches where the waves are then amplified, increasing the rates of erosion. A living shoreline is a mix of living organisms including oyster beds and mangrove trees that dampens the power of the waves. While I believe that the use of eco-friendly soft barriers would be best to prevent coastal erosion, this concept cannot survive in all climates, so a combination of hard and soft barricades in order to protect millions of houses around the world.

Coastal erosion has caused lots of damage to the beaches all around Los Angeles. Just 13 miles away from the coast, USC is able to see the effects on the shoreline. There are many different causes to coastal erosion, but the main factor is the rise in sea levels. In addition, other natural causes include tides, currents, and swells that hit California constantly. A man made cause is building hydroelectric dams which prevents sediment from replenishing the beaches. In an article from The New York Academy of Sciences, they say, “the total sediment supply in California has been reduced by approximately 50% (Slagel and Griggs, 2008), with a total estimated 125 million m3 (163 million cy) of sand impounded in dams (Slagel and Griggs, 2008)” (The New York Academy of Sciences). These artificial barriers stop the natural process of riverbed soil being taken to the beaches. While these dams do not help with the coastal erosion problem in Los Angeles, the main problem is the rise in sea levels. The same article goes on to say, “estimated 1−1.5 m (3.2‐4.9 ft) of shore recession per centimeter (0.4 inch) of sea level rise, and that for 2100 and 1.4 m sea level rise (4.6 ft), cliffs will erode an average distance of 66 m (216 ft) by the year 2100” (The New York Academy of Sciences). The combination of the lack of replenishment and an increase of water in the ocean have led to a rapid increase in the shoreline levels. Human intervention has interrupted the natural processes that kept our coastlines in delicate balance.

Similarly, Southeast Asia faces the same problems caused by coastal erosion which is harming people’s houses. Like in Los Angeles, countries like Bangladesh, Pakistan, Sri Lanka, and India have caused self inflicted harm to their coastlines. In these countries, land development has led to mangroves to be cut down. Initially removing these trees did not seem like an issue, but now the countries are facing the side effects. Mangroves act as natural barriers from waves and storms that hit the coasts of Southeast Asia. An article from Science Direct says the benefits of mangrove forests include, “shoreline stabilization, storm protection, water quality maintenance, micro-climate stabilization, groundwater recharge and discharge, flood and flow control, sediment and nutrient retention, habitat protection and biodiversity, biomass, productivity and resilience, recreation, tourism and culture, hunting and fishing, forestry products, and water transport” (Science Direct). Later research has shown that mangroves do so much for the environment, yet they were still removed from the coasts of Southeast Asia unknowingly.

Just like in Los Angeles, human intervention in Southeast Asia has created damage that could be irreversible. For example, a different article from Science Direct talks about how in Sri Lanka, there has been, “damage to or loss of houses, hotels and other coastal structures, undermines roads, contributes to the loss or degradation of valuable land and disrupts fishing, navigation, recreation and other activities” (Science Direct). For some, the destruction of their property could cost them their entire livelihood, especially if their workplace is destroyed. Specific to Los Angeles, the land development on the Ballona Wetlands has led to some unwanted side effects. The wetlands have been destroyed by humans and are all dried up now. Many animals native to this region are struggling to survive because their habitat was ruined. Another downside to the development of the wetlands is that they no longer protect the coast from waves. An article from the National Oceanic and Atmospheric Administration says, “Wetland vegetation stabilizes the shoreline by holding sediments in place with roots, absorbing wave energy, and breaking up the flow of stream or river currents” (“Conserving Coastal Wetlands for Sea Level Rise Adaptation”). Without these marsh plants, the shore feels the full power of the waves. In addition, with no roots to hold the earth in place, sand is easily swept away in the swell.

Los Angeles has faced the problem of shrinking coastlines by erecting seawalls as a barrier from the waves. The concept behind seawalls are good in theory, but in reality they cause more issues than they solve. As Seawalls Unlimited says, “While installing a wall is a big expense, seawalls offer a long-term solution” (Seawalls Unlimited). The walls are fast and easy to set up. In addition, once constructed, they can provide protection for several decades. The initial cost of fabrication will be paid off because less money will be spent maintaining oceanside property. Although early on building seawalls seemed like a perfect idea, residents now see the side effects of these faulty barriers.

Admittedly, the seawalls are not perfect and cause issues after they are built. These walls are not indestructible, and when they break, they are very expensive to fix. They are also hard to fix once they are broken. As stated in the Los Angeles Times article talking about the Marina del Rey Seawall, “if damage throughout the wall is found to be as extensive as is shown in 61 samples, necessary repairs would cost at least $10 million” (Baird). As seen in the past, any small repair costs a lot of money to fix. In Marina del Rey, only a small section of the wall was damaged. If more were to be damaged at one time, the whole wall might have to be replaced. In addition, the wall disrupts the fragile equilibrium of the coastal ecosystem. The sea creatures living there will not be able to pass through the wall and will be stuck either on the inside or outside. As stated from NBC, “they can have the unintended consequence of harming delicate coastal habitats and the animals that live in them” (Bennington-Castro). The animals will have to find a new habitat and some will end up dying because they are unable to. The changes to the environment are irreversible which is why I believe there are better alternative measures to seawalls.

The better temporary solution to keep the ocean at bay is to create living shorelines consisting of oyster beds and mangroves. The oyster beds break up the power of the waves hitting the coast. Unlike seawalls, oyster beds do not reflect the waves, but instead absorb and dampen their force. An article from Naturally Resilient Communities talking about the benefits of oyster beds says, “Oyster reefs buffer coasts from waves, reducing erosion and creating calmer waters” (nrcsolutions.org). Not only do the oysters perform the same job as a seawall, but they additionally grow and repair damage to their cluster naturally. This means that they will be able to expand to match the increase in sea levels as well as fix holes, unlike seawalls. The mangroves also hold the sand in place, so it is not swept away in the currents. When talking about the benefits of combining mangroves and oyster beds, Frank Pallone says, “Utilizing natural infrastructure can help to effectively mitigate future flooding while benefiting local environments and economies.” (Pallone). Mangrove trees act as a natural drainage system and filter the water which are other added benefits. The trees give back to the environment they are put in by creating structure for small animals to live in. When combined, the two act as barriers, slowing down the effects of coastal erosion.

There are some setbacks to trying to use living shorelines. For example, oysters cannot live all around the world. There are specific salinities and water temperatures they must have in order to survive. In an article from Science Direct talking about the optimal living conditions for oysters, they say, “Our study of gradual water temperature changes from 15 °C to 5 and 25 °C showed that at 37‰ salinity (the normal salinity of South Australian seawater) 13–17 °C was the optimal water temperature range for maintaining lysosomal membrane stability” (Zhang). The lysosomal membrane controls what enters the oyster, so anything too far outside this temperature range and the oysters have little protection against disease. This means that the oysters can only be used for a living shoreline where the water temperatures are between this range. Another restriction to living shorelines is that mangroves can only live in warm climates. Mangroves live in tropical to subtropical conditions, so anything colder than that and they are unable to survive. In an article from the Smithsonian talking about where mangroves can live, they say, “A fluctuation of ten degrees in a short period of time is enough stress to damage the plant and freezing temperatures for even a few hours can kill some mangrove species” (The Ocean Portal Team). This means that mangroves are only suitable to be used around the equator. Both of these limitations show that living shorelines are not realistic for the entire world to use.

Australia is addressing their coastal erosion problem in many different ways. As a surf loving country, many oppose the idea of using seawalls to prevent coastal erosion because they destroy the beaches. This leaves few other options to look to. In a newspaper article from The Guardian talking about coastal erosion in Australia, Wendy Harmer says, “For some it will be a strategic retreat with assets that can be moved, for others it will be building partial seawalls, cliff reinforcement and revegetation” (Harmer). While they will not be able to use living shorelines to the fullest extent, they will still be able to plant coastal grasses that will help with sand retention. Although an extreme measure, some will be forced out of their homes if the ocean gets too close. If residents are too stubborn to use a hard structure that may put their beaches at risk in order to save homes, then friends of theirs may have to move out of their houses. Australia is also talking about pumping sand from the seafloor to their beaches. This will be expensive and the pumps will have to be stationed far offshore, making the solution unrealistic. Australia needs to focus on coming up with better solutions to protect their shores, so people do not end up losing their houses to the ocean. They should work with countries around the world to find the best solution since many other areas on different continents face the same problem.

While Australia is trying their best to steer clear from artificial methods of coastal protection, the indecisiveness is leading to more time being spent arguing than acting. This means that erosion is taking place without a solution in sight. The talk of using coastal grasses to help slow the diminishment of the beaches is a starting point, but this will not be enough. There will need to be more done in order to save their shorelines. Australia needs to be like Los Angeles and look to adopt man made solutions in order to protect their shores. In the same way, Los Angeles needs to see how planting grasses has gone well for Australia and think about implementing them. Seawalls like in Marina del Rey are a start toward a fix, but there needs to be something more to create a more permanent answer. In both places, a combination of artificial and natural resources should be utilized in order for the best results at slowing coastal erosion.

Looking to the future, the world must come together to get the rise in sea level under control. This is all due to climate change. Emissions are the largest cause of global warming, so we must focus on limiting the amount of CO2 produced by large corporations. This will be a world wide effort because if only some countries participate, then it will all be for nothing because other countries will still be polluting the atmosphere. The emissions produced in one country affects the rest of the world. In order to truly address the increased rate of coastal erosion, we must first look at the causes and try to solve those problems first. The debate between using a hard barrier or soft barrier is only for a temporary solution. The one permanent solution is to get the rise in sea levels under control, so people can peacefully live along the coast without worrying about their house being sucked into the ocean. In order to do so, we must stop international corporations from polluting the air. There has to be an international meeting where all the countries agree on a set of laws to slow down climate change. This will prevent the large companies from running to a country with more relaxed emission standards. Humans have to take care of the environment, or else we will start losing precious resources that keep us alive.

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