Earth Systems in Action: Development and Coastlines
As you have just discovered, humans have undertaken a wide range of initiatives to try and protect some coastlines and limit the amount of coastal erosion that is taking place. These initiatives include the construction of hard protective structures such as breakwaters and seawalls or the imitation of natural processes that include the placement of sediment in key locations or planting vegetation to stabilize loose unconsolidated sediment. The decision to use one method over another is extremely complex, requires a solid understanding of the system to be protected, and consideration of the economics and politics of a project.
Suppose, for example, that you own beachfront property and historically the beach in front of your house has been retreating landward, toward your house, at a rate of a meter per year for the last decade because of the combined effects of erosive storms and reduced sediment supply. On the basis of the historic trend, it is clear that within another decade the waves will be at your door. It is clearly, then, in your best interest to develop some sort of project that will help reduce the erosion and cause the beach to begin building seaward again. What are your options?
You could go to the local city council and suggest that a series of groins be placed along the beach in a location that will help trap sediment carried by longshore transport. For this to be effective, you would, however, need to have an excellent understanding of the longshore transport patterns on a daily and longer time frame. Placement of the groin in the wrong place could actually have a negative effect on the beach at your property (depending on the direction of transport) and enhance the erosion. Additionally, you would have to consider the impact of such a structure to the neighboring beaches. Do you think that your neighbors would advocate for structures to protect your beach if it would then also cause erosion in front of their properties? What about the cost of such a structure and who would pay for it? Projects such as this can cost millions or tens of millions of dollars, and you do not have the finances to cover the costs. So, who will pay for it? Suppose I am a taxpayer in a more landward located county. Do you think I would advocate for my taxes to be used to protect your beach-front property if the school my kids attend needs new technology and computers that are normally paid for by the same tax money?
In this example, numerous systems need to be considered, ranging from the natural longshore transport system to the local economic and political system. It is clear that situations such as this are extremely complex and require careful planning and implementation, and, in most cases, not everyone is content with the final outcome.