Surfrider wrote this paper to educate coastal activists about "beach nourishment." Many coastal experts believe the term "beach nourishment" is a misleading term and that these projects should be called "beach dredge and fill projects" to reveal their true impact on the beach. Surfrider Foundation’s Board of Directors decided to use the term "beach fill" to describe this process of engineering beaches. Beach fill is an engineering method to address coastal erosion that is becoming a more common erosion response tool considered by many coastal managers, public agencies, engineers and coastal residents. There are many issues involved with beach fill that local citizens should understand so they can decide whether beach fill is appropriate for their beach. This paper details the costs and benefits of beach fill and provides a comprehensive list of references on the topic.
Beach fill refers to the process of placing sand on a beach where it previously eroded. It is also known as beach renourishment, beach replenishment, and beach dredge and fill. Beach fill is typically a response to coastal erosion that threatens to undermine property, buildings, and infrastructure. For a long time, coastal engineers preferred "hard structures" to protect coastal property. “Hard structures” include responses such as seawalls, groins and jetties. More recently, engineers and coastal communities use "soft engineering" such as beach fill, dune creation and restoration, sand scraping and dune reshaping. In many places, beach fill is the primary method used for property protection. This change towards “soft engineering” efforts is occurring because hard engineering projects are expensive, permanent, can cause additional erosion problems, and are unsightly. While usually preferred to hard engineering, beach fill is not a “silver bullet” for coastal erosion problems. Beach fill is also expensive, has poorly understood ecological effects and better alternatives are often available. Because of the recent emphasis on using beach fill and a perceived lack of information on the issue, Surfrider chose to write this paper to educate activists so they have the facts needed to make wise decisions about management of their beaches.
This document has two main sections that detail the costs and benefits of beach fill. The paper further breaks down each of the sections into the different categories of costs and benefits. For further information on beach fill, see the Surfrider Foundation Beach Preservation Policy for Surfrider's perspective on the available alternatives.
Why fill a beach?
Coastal managers often choose beach fill to restore a beach that is eroding. Approximately 80% of the nation’s beaches are eroding (cite) and since most beaches support a lucrative visitor industry in coastal towns and protect valuable coastal property from storm damage, many people view beach erosion as a significant economic loss and are willing to spend a lot of money in response. For example, in 1998, California’s beaches generated $14 billion dollars of direct revenue. When the indirect and induced benefits of this spending are added, California’s beaches total contribution to the national economy is $73 billion. These figures show that beaches have enormous value so fill projects can have very strong economic justifications.
An important point is that in many cases beach erosion problems are the result of prior shortsighted decisions. Coastal erosion simply means that a stretch of beach receives less sand than flows away from it. Left alone, erosion is often not a problem because beach width tends to remain the same along a naturally eroding shoreline over long periods of time. Beaches are naturally very dynamic and may erode or accrete through storms and seasons. It can be disheartening to see a narrow beach after a big winter storm, but more often than not the beach will widen again during calmer periods. The sand deficit only becomes a problem when an eroding shoreline threatens to undermine houses, roads and other structures that people built along the coastline. From this perspective, the decision to build too close to an eroding coastline brings on the erosion problem. Furthermore, in many cases previous shoreline protection projects (like groins or jetties) have disrupted sand supplies to beaches and caused erosion problems. For many beaches on the West coast, flood control projects and dams cut off natural sand supplies. Armoring naturally eroding bluffs also restricts natural sand flows to beaches. Shoreline structures such as groins, jetties and seawalls can also disrupt the littoral flow of sand and reduce the sand supply to a beach. Sea level rise and subsidence of the coast for natural and anthropogenic reasons can also result in erosion. For example, in Texas and Louisiana the coast is subsiding from oil extraction. These examples show why fill can be a “band aid” approach because it does not address the underlying chronic deficit of sand at a beach. In some places, restoring natural sand flows, moving buildings away from the coast (or nor rebuilding them when damaged by storms) or increasing setbacks for new buildings may offer better alternatives to beach fill.
How do you fill a beach?
The majority of beach fill projects involve mining or dredging sand from an offshore source, transporting it to the beach and bulldozing the fill from 100 to 250 ft out into the water. It is an intensive construction project and each part of this process can harm the local environment. This section will briefly describe each part of the process and highlight the potential environmental effects.
Dredging and Mining
Approximately 95% of beach fill sand comes from offshore deposits. Sand from these offshore “borrow sites” is usually dredged and piped from the source site to the beach and bulldozed into place. Sand dredged from beyond the 3-mile state limit on the Outer Continental Shelf (OCS) is managed by the Marine Minerals Program of the US Bureau of Ocean Energy Management. Sand is also dredged from inlets, estuaries, lagoons and adjacent beaches where sand accretes. Some of these sources are less common because they sometimes cost more and contain sand that is too fine to use as “beach quality” sand. Other potential sources on land are sand from inland quarries and sand cleaned out of debris basins that trap sediment from floods. Sand dredging and mining have many potential environmental impacts, which a subsequent section will describe in detail.
After dredging or mining sand, the beach fill is transported by truck or pipeline and then pumped as a slurry into large piles on the beach. Bulldozers then push the fill out into the planned artificial profile. Some beach fill projects deposit most sand into nearshore sandbars (berms) under the assumption that currents will move sand onto the beach. These activities also have many environmental effects associated with them that will be discussed below.
Some beach fill projects are referred to under names such as sand recycling or sand bypass. Sand recycling projects dredge sand from an area where it accumulates and move it to “refill” the area that eroded. Sand bypass systems move sand past a structure that restricts the flow of sand along the coast, commonly a jetty. Sand is dredged on one side of the structure and then pumped onto on the other side. Some sand recycling or sand bypass systems are permanently installed on the beach and are designed to replace the natural sand flow.
Benefits of Beach Fill
Beach fill projects can protect property, houses and infrastructure from storms. The projects increase beach width and add sand to nearshore sandbars, which provides a buffer against storms and erosion. In December 2000, the Army Corp of Engineers published a study that compared the property damages from Hurricanes Bertha and Fran to beaches in North Carolina with and without beach fill projects. The study found that beach fill projects reduced storm damages but the study could not estimate the value of this benefit.
Another benefit of beach fill is avoiding construction of hard and permanent shoreline structures such as seawalls, revetments and groins. Shoreline armoring can, in many cases, result in total loss of the beach. When viewed from this perspective, avoiding shoreline armoring along the coast can be a significant benefit.
For some species that depend on the beach for habitat, beach fill may provide environmental benefits. In areas where the beach has completely eroded, often where seawalls have been constructed, restoring the beach through fill can replace some lost habitat. Some researchers found these habitat benefits for brown pelicans, loggerhead turtles and piping plovers. An important point is that these habitat benefits occur on a case-by-case basis. In many places, beach fill projects damaged habitat for these species.
The recreational benefits of beach fill include increasing the available beach area and sometimes possibly improving surfing conditions. Restoring sand on a beach can increase “towel space” until the beach erodes again (often faster with artificially filled beach profiles), so people have more area for recreation. In some cases, beach fill projects temporarily improved surfing conditions by creating a more pronounced system of nearshore sand bars. The “Superbank” on the Gold Coast of Australia is an example. Superbank is a surfing area that connects two previously existing surfing areas, Snapper Rocks and Kirra, to create a surfing wave that is almost a mile long. This was created by additional sand filling in the area between the two existing spots and the sand is coming from a sand bypass system that is constantly pumping sand across an inlet.
The economic benefits of beach fill include reduced storm damages and increased tourism. A beach fill project can lower the chances that a storm will damage coastal property and infrastructure. This reduced risk is an economic benefit to property owners. Beach fill projects also provide more recreational beach area and possibly attract more visitors. With the considerable value of coastal property and tourism, these benefits can be substantial.
Impacts of Beach Fill
Beach fill can create a false sense of security in storm-prone areas, with additional development following fill projects. The additional development will then result in larger damages when a storm eventually hits. Furthermore, the new development will require perpetual fill to protect the property. These situations count as costs because in many cases fill projects are proposed as one-time expenditures when in reality they prompt larger, perpetual expenditures over time.
Beach fill projects have been linked to increased swimmer injuries, as the sand placement may cause sharp drop offs into deep water allowing larger waves to crash directly on the shore rather than being broken up by nearshore sand bars. This was seen in Harvey Cedars, NJ. Senator Frank Lautenberg called for an investigation into these sorts of injuries in 2008.
Fill projects can have a number of environmental impacts, many of which are still poorly understood. Some of these potential impacts include burying onshore or offshore habitat, and using sand that is not compatible (grain size or color) with existing beach sand. These differences in sand characteristics can affect the reproductive of sea turtles or other species that utilize the beach for nesting or reproduction. These impacts are discussed in more detail below and in this separate article on beach ecology.
Offshore Dredging Impacts
Dredging for sand at offshore ‘borrow’ sites kills bottom dwelling species and increases turbidity at the site and adjacent areas. In some studies, species reestablished themselves within a year but other sites showed long-term effects from the dredging. Despite the many projects and the money spent for monitoring, no long-term studies have documented the level of impact that continuous dredging has on offshore communities. Rigorous research on direct impacts to bottom organisms and indirect impacts due to long-term increases in turbidity is needed.
Fill placement impacts
The dumping of fill can substantially disrupt the natural beach system. A slurry of muddy sand is pumped onto the beach, often through pipes that extend a mile or more from the offshore dredge site. The slurry is often a mixture of fine-grained silt and sand. This material is then bulldozed into place, forming a highly artificial profile that often extends hundreds of feet into the water. In instances with inland sand sources, trucks must carry the fill material onto the beach where bulldozers also move it into place. Temporary roads are often built for vehicle access. Beach use is prohibited during this phase and natural ecosystems are disrupted by heavy construction equipment. Researchers have found that these activities can significantly reduce the abundance of several species that live in beach sand. Many of these species are important food sources for surf zone fish and birds. Disrupting the food chain affects many of the species highly valued by fishers and tourists.
Beach fill has several potential impacts: burying existing habitat, changing the sand composition of the beach and clouding nearshore waters as the beach fill settles. By placing new fill material on the beach, beach fill buries existing ecosystems on the beach and in nearshore areas. This can disturb both the sand-based ecological communities on the beach and the ecosystems immediately offshore, such as eel and surf grass and hardbottom reefs. In Florida, beach fill projects bury nearshore hardbottom reefs and can disrupt their associated fish communities, which normally use these habitats as important nursery areas. Researchers in Florida found in one case, a fill project burying 12 acres of nearshore reefs decreased fish abundance by 10 to 30 times. The effects of beach fill on nearshore softbottom systems are more ambiguous. A recent study by the Army Corps of Engineers on the effects of a beach fill project in northern New Jersey found few biological impacts on fishes using sand bottoms. These results are not always applicable to regions outside the study area.
The sand composition of beach fill can harm many beach-dependent species. Differences in offshore grain size, composition, and color can result in steeper beaches, large scarps (ledges in the shoreface of the beach), carbonate sediments that can rapidly decompose into muds, and offshore sand that can be a different temperature than natural sand. These differences can disturb sea turtles (of which all species are listed as endangered or threatened). Sea turtles climb the beach to lay their eggs in nests. Beaches with steep scarps or have sand that is too difficult to dig in can prevent sea turtles from effectively laying their eggs. In addition, different sand colors vary the temperature of the beach. The temperature of the sand plays a role in determining the sex of the incubating turtles, so sand that is too dark can result in an imbalance in the sex of newly hatched sea turtles. A study on the effects of nourished beaches on loggerhead turtles at Jupiter Island, Florida found all of the impacts listed above.
In addition to disrupting the beach ecosystem, the projects often affect nearshore water quality. As the sand settles, fine particles wash away and turbidity increases adjacent to the project. Although it is sometimes argued that this imitates the natural processes that deliver sand to a beach via rivers, the timing of these projects may not mimic the timing of natural sediment-supplying events, which makes the ecological impact incomparable. On the East Coast, most natural sand supplies do not occur in this manner, as very few rivers carry enough sediment to be a significant source at any time of year. As such, any fill project will be a major departure from the natural cycle.
Cumulative Impacts of Beach Fill
Many scientists are concerned about the long-term cumulative impacts of beach fill. Most research studies and permit reviews only assess the effects of a single beach fill project and ignore the combined effects of projects in surrounding areas and future projects at the same site. In a letter dated June 27, 2000 seventy Ph.D scientists expressed concern over the continuous absence of cumulative impact analysis, despite more than fifty large offshore dredge and fill projects in Florida in the last 40 years. They pointed out that permitting agencies routinely declare that no significant cumulative impacts exist when, in fact, no studies have specifically looked at this question.
Overall, existing scientific research does not support the routine conclusions of federal, state and local management agencies that beach fill has minimal long-term impacts. Proponents argue that beach fill projects disturb ecosystems for a several month period and then return back to their original state, so they conclude that fill projects have minimal long-term impacts. This conclusion ignores the fact that most fill projects are recurrent, so the project repeatedly disturbs the nearshore environment for an indefinite period. Almost no independent research has assessed the long-term, cumulative impacts of beach fill. Conservatively speaking, it is premature to conclude that no significant impacts occur from these projects. .
During construction, the public temporarily loses beach access. In many parts of the East Coast and particularly in New Jersey, beach fill projects have buried or permanently altered surfing areas. In addition, beach fill projects can sometimes result in a steep beach and create a dangerous “shorebreak.”
Another issue is public funding of beach fill projects on beaches without adequate public access. Along the East coast, beaches have often been nourished at the public’s expense even though the public had little or no access, with projects often primarily fronting private homes or hotels. As of 19XX, Congress requires projects that use federal funds to provide at least minimum levels of public access.
Beach fill projects can be extremely expensive and require continuous maintenance. Research on a comprehensive database of beach fill projects along the East coast, Gulf coast and Great Lakes found that by 1996 the U.S. had spent an estimated $2.4 billion (1996 dollars) on beach fill and that annual expenditures were approximately $100 million (1996 dollars). Most importantly, annual expenditures are increasing rapidly as more communities choose beach fill. These researchers estimated that the future 10-year costs of “renourishment” all the developed shorelines in New Jersey, North Carolina, South Carolina and Florida were $4.4 billion (1996 dollars). This study found that the average cost per mile in these states would be $5.5 million per mile. New Jersey had the highest costs at $17 million per mile and South Carolina had the lowest at $3.3 million per mile. These estimates show that beach fill projects are expensive and will require much larger expenditures in the future.
Beach fill projects are also short-term and need subsequent maintenance. Analysis of beach fill projects on the East Coast shows that the majority (62%) of projects lasted for 2-5 years and over a quarter (26%) survived less than a year. These data show that beach fill projects are rarely a one-time expenditure so the costs must be considered over the long-term. In this context, the true costs to maintain the beach can be very large, which the next few examples demonstrate. A recent project in New Jersey to nourish a 21-mile stretch of beach for 50 years is projected to cost $210 million or $10 million a mile. In North Carolina, another project to nourish 14 miles of beach is projected to cost $1.8 billion. These costs just cover the construction costs for the project and do not reflect the environmental damages that result.
A detailed state-by-state accounting of money spent on beach fill projects in the U.S. was compiled by the Program for the Study of Developed Shorelines.
Over the last several decades, reliance on hard structures for shoreline protection became unpopular because they are unsightly, expensive and can harm beaches. At the same time, beach fill developed into an increasingly popular engineering method to deal with coastal erosion. These projects temporarily restore the beach, can provide a buffer against storm damage and increase “towel space” on the beach. Beach fill projects are also expensive and often short lived, have poorly understood ecological consequences and may become increasingly problematic as sand resources diminish and sea level continues to rise. Once started, beach fill projects must be regularly maintained in perpetuity. They are not a long-term solution for coastal erosion problems. In many cases, limited retreat from the coast may be the best alternative for financial, environmental and aesthetic reasons. In cases where retreat is presumably impractical, coastal managers and the public should clearly understand the financial, recreational, environmental, and economic impacts of beach fill before committing to what will become a never-ending and recurrent expenditure.
Bibliography & Information Sources:
- ↑ Valverde, Hugo R., Arthur C. Trembanis, and Orrin H. Pilkey. “Summary of Beach Renourishment Episodes on the U.S. East Coast Barrier Islands.” Journal of Coastal Research. 15(4) Fall 1999. pp. 1100-1118
- ↑ King, Phillip. 1999. The Fiscal Impact of Beaches in California. A Report Commissioned by The California Department of Boating and Waterways. Public Research Institute. San Francisco State.
- ↑ (Inman, Douglas L. and Birchard M. Brush. (1973) The Coastal Challenge. Science. 181(1):20-31.).
- ↑ 4.0 4.1 4.2 4.3 4.4 Beach Nourishment and Protection. National Research Council. National Academy Press. 1995.
- ↑ Army Corps of Engineers, “Hurricane Fran Effects on Communities With and Without Shore Protection: A Case Study at Six North Carolina Beaches.” US Army Corps of Engineers Institute for Water Resources. December 2000.
- ↑ Newell, R.C., L.J. Seiderer, N.M. Simpson, and J.E. Robinson. “Impacts of Marine Aggregate Dredging on Benthic Macrofauna off the South Coast of the United Kingdom.” Journal of Coastal Research. 20(1). Winter 2004. pp. 115-125.
- ↑ Peterson, Charles H., Darren H.M. Hickerson, and Gina Grissom Johnson. “Short-Term Consequences of Nourishment and Bulldozing of the Dominant Large Invertebrates of a Sandy Beach.” Journal of Coastal Research. 16(2) 368-378.
- ↑ Manning, Lisa M.; Peterson, Charles H.; Fegley, Stephen R. "Degradation of Surf-Fish Foraging Habitat Driven by Persistent Sedimentological Modifications Caused by Beach Nourishment." Bulletin of Marine Science, Volume 89, Number 1, January 2013, pp. 83-106(24)
- ↑ http://www.palmbeachdailynews.com/news/news/dep-says-town-must-build-artificial-reef-costs-yet/nXbr8/
- ↑ Lindeman, K.C. 1997. Comparative management of beach systems of Florida and the Antilles: applications using ecological assesment and decision support procedures. Pp. 134-164. In G. Cambers, ed. Managing beach resources in the smaller Caribbean island. UNESCO Coastal Region & Small Island Papers #1, 269 p.
- ↑ Lindeman, K.C. and D.B. Snyder 1999. Nearshore hardbottom fishes of southeast Florida and effects of habitat burial caused by dredging. Fish Bull. 97(3):508-525
- ↑ Wilber, D.H., D.G. Clarke, G.L. Ray, and M. Burlas. “Response of surf zone fish to beachnourishment operations on the northern coast of New Jersey, USA.” MarineEcology Progress Series. 250:231-246. 2003.
- ↑ p. 112
- ↑ Steinitz, Mary J., Michael Salmon, and Jeanette Wyneken. “Beach Renourishment and Loggerhead Turtle Reproduction: A Seven Year Study at Jupiter Island, Florida.” Journal of Coastal Research. 14(3) 1000-1013.
- ↑ Hatheway, Darryl, personal communication, 2001 and “Surfers fight to stop Sandy Hook beach fill.” Asbury Park and Press. July 1, 2001.
- ↑ Trembanis, Arthur C., Hugo R. Valverde, and Orrin H. Pilkey. “Comparison of Beach Renourishment Along the U.S. Atlantic, Great Lakes, Gulf of Mexico and New England Shorelines.” Coastal Management. 27: 329-340. 1999
- ↑ Leonard, Lynn, Tonya Clayton, and Orrin H. Pilkey. “An Analysis of Replenished Beach Design Parameters on U.S. East Coast Barrier Islands.” Journal of Coastal Research. 6(1) Winter 1990. pp. 15-36.
- ↑ US Army Corps of Engineers. www.nan.usace.army.mil/project/newjers/factsh/pdf/barneg.pdf
- ↑ Needs reference