Many geologic processes affect the landscape of the Delmarva Peninsula drastically, but one specific process has major economic implications as well. The process of coastal erosion, which is defined as the actual removal of sand from a beach to deeper water offshore or alongshore into inlets, tidal shoals and bays, is one of the most detrimental geologic events to this region’s economy (Scientific American). This type of erosion can result from many factors including rising sea levels and changing weather patterns. A majority of coastal erosion is episodic, meaning that the erosion occurs in small episodes over short periods.
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During intense storms, such as hurricanes or nor’easters, the coastal shoreline can be eroded in a day or even several hours. Erosion is also sporadic, meaning that erosion rates in the same region are not always uniform (Stewart). In the Delmarva region, the beaches are a main recreational attraction, and the resulting tourism boosts the economy. Therefore, when these geologic events do occur, the primary concern of governments in these areas is beach replenishment. Beach replenishment is a costly endeavor, but a necessary one.
Some recent replenishments in southern Delaware have been in the range of 3 to 5 million dollars, and are not guaranteed to last. As a result, it is important to understand the process of coastal erosion as well as the replenishment techniques in order to maximize the economic benefits of the Delmarva beaches. Coastal erosion results from interaction between ocean waves beach sediments. Human influence, mainly urbanization, also plays a large role. Beach systems are considered to be in dynamic equilibrium and are essentially temporary geological features. The sand levels on beaches are constantly in flux.
The common misconception is that once sand is removed off the beach back into the ocean, it is lost. However, when sand is moved from one location to another it is simply recycled and returned into the system. For example, winter storms may remove significant amounts of sand, creating steep, narrow beaches. In the summer, gentle waves return the sand, widening beaches and creating gentle slopes (Haznet).
The many factors involved in coastal erosion, including human activity, sea-level rise, seasonal fluctuations, and climate change, allow sand movement rates to hange year to year. Between 80 to 90 percent of sandy beaches are currently in erosion cycles at rates ranging from only a few inches to over 50 feet per year, but the issue that causes beachgoers concern is the idea that this cyclical behavior is not balanced in equilibrium, and the erosion in the winter outweighs the sand return in the summer. (Haznet) Below are pictures of beach erosion in Bethany Beach, Delaware. The picture on the left (Figure 1) is erosion following Hurricane Isabel in 2003, while the picture on the right (Figure 2) is erosion following the 2009 Nor’easter.
The process to mask some of the effects of beach erosion is known as beach nourishment. Beach nourishment, or replenishment as it is commonly referred to, is the process of dumping or pumping sand from elsewhere onto an eroding shoreline to create a new beach or to widen the existing beach. Many times, a dredge removes the sand from a borrow site in the ocean and delivers sand to the beach using pipes. The sand arrives on the beach in the form of slurry, which is a mix of sand and water. The slurry is then moved to the desired locations on the beach using heavy-duty machinery.
This process does not prevent erosion from occurring in the future, however it simply adds additional material that was lost. As a result, this process is repeated continually in order to maintain the beach (Barber). Each nourishment is expected to have a lifetime, meaning that the nourishment will wear away eventually. Lifetimes of nourishments are difficult to predict because of the variety of factors involved with erosion rates, but it is helpful to understand that once all of the nourishment sand is eroded away, the beach will return to its pre-nourishment width, and would need to be re-nourished again (Barber).
While it is clear to see that beach nourishment is an option that provides advantages for a beach community, there are also several disadvantages. Beach nourishment sand usually erodes faster than natural sand on the beach. In fact, the erosion rate of nourishment sand is two to three times faster than that of regular sand (Barber). Additionally, the minimum expenditure for a beach nourishment is anywhere between 1-2 million dollars, with larger, more long-term nourishments costing much more.
Finally, nourishments can both damage certain beach life, as well as change the composition of the beach (Barber). Below are pictures from the Bethany Beach nourishment project in the fall of 2009. The picture on the left (Figure 3) shows the process of pushing old sand away and pushing new sand around to create a wider beach. The picture on the right (Figure 4) shows pipes that were responsible for pumping sand from offsite pumping locations back onto the beaches in Bethany. The economic implications of beach erosion are widespread as well.
The financing of beach nourishments, the lifetime of the nourishment, as well as the cost of rising homeowner’s insurance all play major factors. As mentioned earlier, minimum beach nourishments are around 1-2 million dollars, while some recent projects in Delaware have run from 10-20 million dollars (Parsons 92). Beach nourishments include costs associated with labor, capital, and raw materials. Many of these costs are recurring as well. The issue with these types of projects is the source of the funding. For a majority of the projects, funding is usually a mix of local, state, and federal tax money.
State and local taxpayers have access to the beaches that they are paying to replenish, but national taxpayers from other states may not, which creates an interesting dilemma. (Barber) Taxpayers will most likely be unhappy if they are funding a service that they will not receive the benefits of, therefore, project managers for nourishments must consider the level of taxpayer access to the beach as a factor in their decisions. Another factor that affects the economic value of beach nourishment is its lifetime. Many times, project engineers will overestimate the lifetime of the new sand, which skews the cost- benefit analysis.
If a nourishment is projected to last for 8-10 years, it may be worth the 5 million dollars of tax money that is spent, but if the beach will erode within the next few years, the project may not be cost effective (Barber). George Parson, a Delaware professor, and Michael Powell, a DENREC employee, have developed a formula for determining the amount of money lost per foot of beach eroded. Their formula includes factors such as land lost, economic value of coastal property lost, and income lost from recreational services.
Using their formula, they calculated that Bethany Beach as a whole will lose $16. 5 million with just 1 foot of beach lost. (Parsons and Powell 100) These economic statistics are particularly striking since Bethany Beach is only a little over 1 square mile. Finally, the cost of homeowner’s insurance on beachfront properties may be one of the most important factors. Housing insurance alone is expensive in itself, but when one is insuring a property in a disaster prone beach area, the prices skyrocket. These prices do not even include the costs of precautions taken to prevent damage, such as storm shutters.
Recently, legislation has proposed the Homeowner’s Defense Act, which would allow states to pool risk to spread out the costs of natural disasters. Although the costs of insuring these types of properties are still high, the statewide pools will help limit the risks for homeowners (Epstein). If this bill passes, it will ease the pain on individual homeowners, however owning a home in a beach area is still risky. The effects of beach erosion and the costs of beach replenishment were experienced just last fall in our region.
A Nor’easter in November 2009 caused immense damage to the beaches of southern Delaware. One specific case study that will fully demonstrate both the geological impacts and economic implications of a storm of this caliber is the analysis of Sea Colony in Bethany Beach, Delaware. Sea Colony is a private beach community, which presents a different look on the entire replenishment process. The Management of Sea Colony is responsible for hiring a private contractor to conduct the replenishment and the Sea Colony homeowners are assessed a fee as a result.
Dave Creighton, Operations Manager of Sea Colony Recreation, had the following to say about the 2009 replenishment project: “Following the 2009 Nor’easter, the Delaware Department of Natural Resources and Environmental Control authorized Sea Colony to hydraulically dredge approximately 290,000 cubic yards of sand from an offshore borrow area and deposit it along 2,350 linear feet of shoreline extending from the southern tow limits of Bethany Beach south to the northern limits of the community of Middlesex Beach, Bethany beach, Sussex County, Delaware.
“The dredging division of Weeks Marine, Inc. from Covington, LA was awarded the contract to do the replenishment. The ecological restoration division of DENREC was responsible for installing the clay/sand crossovers, planting of the dune grass and installation of dune fence. The 290,000 cubic yards of sand cost approximately $2,500,000, while the ecological restoration work cost approximately $120,000 (Creighton). Although some of the setup costs were offset by taxpayer money, Sea Colony homeowners were responsible to fund a project that was not guaranteed to last.
There are 2200 units in Sea Colony, and each unit was charged approximately $1,000 in addition to their regular recreation charges. However, these costs are necessary ones. “The biggest attraction in Sea Colony is the beach, and if it isn’t there, we lose revenue. The population in the summer is sometimes 15 times that of the year round population and we cannot afford to miss that opportunity” (Creighton). Beach erosion will continually be a costly geologic process for the Delmarva region for years to come.
The eroding beaches may experience temporary sedimentary loss, or long-term loss. Additionally, erosion rates can be different in different spots on the same beach. Therefore, it is difficult to determine if beach nourishment will be beneficial or not. Poorly executed beach nourishments can damage surrounding ecosystems and destroy wildlife. Even if nourishment is done properly, the new sediments will not last as long as the original sand. However, the beaches in this region bring significant tourism to this area in the summer months.
Cost benefit analysis is difficult in this situation, but the economic activity that is generated through beach tourism may help to compensate for the costs of beach nourishment. Below are several pictures demonstrating different aspects of beach erosion and beach replenishment. This is a picture of slurry, the water and sand mixture, being pumped onto a beach (Figure 5) This is a picture of a dredging vessel, which collects sand and pumps it onto beaches (Figure 6) This is a diagram of how beaches adjust seasonally with different wave action and erosion (Figure 7)
