Why is coastal erosion a relevant topic to so many people on a global scale? According the United Nations Atlas, 40% of the world’s population lives within 100 kilometers of the coast (CC, 2016). Climate change, rising sea levels, and coastal erosion pose threats to the world’s shorelines. From a monetary perspective, coastal erosion is responsible for about $500 million in coastal property loss annually – including structure damage and land loss (USCRT, 2016). It is imperative to give this topic our consideration in order to find sustainable long-term solutions. The purpose of this article is not to soothsay a rising sea-level doomsday; rather it is meant to encourage research for coastal erosion mitigation techniques that can prevent any future property/land loss and even potentially lead to shoreline accretion (gain in shoreline).
Several structural solutions exist for coping with coastal erosion. Such options include seawalls, groins, rip-rap, levees, and man-made islands. These alternatives can be expensive and require costly maintenance – not to mention, the adverse effects cause by rigorous water diversion. These structural alternatives may very well be commendable solutions; however, more natural and cost-effective solutions exist. More natural methods for controlling erosion include beach replenishment/nourishment, wetland protection, and dune stabilization with vegetation (USCRT, 2016). Many of these methods are temporary fixes that can be undone by major storm events; therefore, a more permanent solution is needed.
One such solution might be submerged manmade reefs. Multi-purpose artificial reefs (MPAR) are marine structures that serve as offshore coastal protection; they can also be more cost-effective than coastal defense structures due to construction materials and size. The main feature of reefs (natural or artificial) is their ability to dissipate wave energy that might otherwise result in significant coastal erosion problems and loss of usable beach space. MPAR’s have the potential to provide invaluable maritime environmental assets globally, if properly managed. In one study conducted by Lee Harris at Gran Dominicus Beach, it was found that utilization of submerged manmade “Reef Balls” led to an accretion of 10 meters -13 meters in the lee of the reefs from February of 1999 to April of 2001 (Harris, 2016). This is one example of a successful MPAR used to combat coastal erosion mitigation; success ultimately depends on long-term sustainability and the practicality of implementation.
Coastal erosion has the potential to affect nearly half of the world’s population – including infrastructure and property. Several temporary/costly solutions exist to deter future loss of coastlines. Future research needs to be conducted to test the viability of MPARs as a more permanent alternative. This not to say that MPARs are the only possible solution, but at least there appears to be a glimmer of hope for a more sustainable and long-term response to global coastal erosion.
SOURCES:Coastal Challenges (CC), “UN Atlas: 44 percent of us live in coastal areas.” https://coastalchallenges.com/2010/01/31/un-atlas-60-of-us-live-in-the-coastal-areas/. April 2016Harris, Lee E., Coastal & Ocean Engineering and Oceanography, “Submerged Artificial Reefs for Beach Erosion Control.”US Climate Resilience Toolkit (USCRT), “Coastal Erosion.” https://toolkit.climate.gov/topics/coastal-flood-risk/coastal-erosion. April 2016