BEACH NOURISHMENT: Global Perspectives and Local Applications to the North Carolina Coastline Bryant C. Cooney Kari D. Forrest Juliana R. Miller Florian U. Moeller Jennifer K. Parker Fall 2003 Carolina Environmental Program Capstone Experience conducted at the UNC Chapel Hill Institute of Marine Sciences in Morehead City, North Carolina Field Site Director: Rachel T. Noble 1 TABLE OF CONTENTS I. INTRODUCTION……………………………………………………………………3 A. What is beach nourishment?........................................................................................3 B. What causes beach erosion?.........................................................................................4 II. BEACH NOURISHMENT AROUND THE GLOBE……………………………….7 A. Introduction…………………………………………………………………………..7 B. Western Europe………………………………………………………………………8 C. East Coast of the United States………………………………………………………23 III. SUMMARY OF NORTH CAROLINA PHYSICAL AND BIOLOGICAL CHARACTERISTICS PERTINENT TO BEACH NOURISHMENT…………………35 A. Physical Characteristics of the NC Coast…………………………………………...35 B. Biological Characteristics of the NC Coast………………………………………….36 IV. SUMMARY OF UNITED STATES ARMY CORPS OF ENGINEERS (USACE) BIOLOGICAL MONITORING PROGRAM REPORT ON BIOLOGICAL MONITORING PROGRAM FOR NEW JERSEY EROSION CONTROL PROJECT..41 A. USACE Biological Monitoring Program Overview………………………………...41 B. Sampling design and methods………………………………………………………..42 C. Nourishment area assessment………………………………………………………...43 D. Borrow area assessment……………………………………………………………....46 V. SHORTCOMINGS OF THE USACE-BMP DOCUMENT........................................ 47 A. Clarity........................................................................................................................... 47 B. Focus ........................................................................................................................... 49 C. Oversights.................................................................................................................... 49 D. Analysis of Data.......................................................................................................... 51 E. Conclusion................................................................................................................... 53 Total .................................................................................................................................. 55 Total .................................................................................................................................. 55 VII. RECOMMENDATIONS .......................................................................................... 61 VIII. REFERENCES CITED............................................................................................ 63 2 I. INTRODUCTION A. What is beach nourishment? Beach erosion has become a major problem for many coastlines around the world. Scientists and coastal managers have been working on ways to solve the problem of coastal erosion, and these solutions involve both hard structures such as groins and jetties and soft solutions like beach nourishment – projects comprised of borrowing sand and re- depositing it on the beach. Beach nourishment has recently become a more popular solution to the problem of erosion; however it has been around for many decades. It is important to realize that erosion is only a problem because people care a great deal about their beaches. There are many reasons why people care about preserving beaches and thus are interested in perfecting the beach nourishment process. Beaches are great sources of recreation. Swimming, surfing, sunbathing, playing beach volleyball, walking, running, kite-surfing, and building sand castles are only a few of the activities people do on beaches for exercise or clearing the mind and soothing the soul. Douglass (2002) refers to America’s beaches as “America’s longest playgrounds.” Approximately half of the world’s population lives within 100 km of an ocean and 51% of the United States’ population lives in a coastal county. In addition to the permanent residents, roughly 180 million people will visit coastal communities annually (ORCA, 2003). It is easy to see that beaches are very important to a very large proportion of the world’s population. Because of their recreational value, beaches are very large tourism industries, generating large amounts money for local economies. There are many regions that are famous for their beaches and it is these areas that are the main attraction to several parts of Spain, Italy, Australia, Florida, California, Florida, North Carolina, and the Caribbean. Beaches are valuable pieces of land that people love to be around and are “economic engines” (Douglass, 2002) that keep some local communities running. Some of the jobs beaches produce include lifeguards, surf shops and lessons, beach merchandise, hotels, seafood and restaurants, fishing, and boardwalks. The loss of beaches would result in a vast decrease in the job market. One specific example of how important the beaches are to jobs is California: 800,000 jobs contribute $14 billion in wages (Douglass, 2002). According to the tourism council, in North Carolina, over $10 billion comes in annually into the economy due to tourism and over 180,000 jobs are generated (NCSBPA, date not given). Furthermore, high value can be, and is, placed on wanting to live within a view of the water. This prime real estate on the water can be fleeting, however, as it can quickly be lost as the shoreline disappears due to beach erosion. According to Douglass, “Anything that hurts the beach also hurts the economy” and it is more true today than it has ever been. However, development along the shoreline of the world’s oceans is a controversial matter. There are opposing opinions. Some believe that development along the shoreline should always be possible, and that it should be possible to continually conduct beach nourishment to save homes even in areas that are considered high erosion areas. Others believe that either development should be prohibited, or that the buildings should simply be allowed to be reclaimed by the sea and not rebuilt after beach erosion takes place, because it was unintelligent to build on such a dynamic piece of land in the first place (UNCTV, date not given). 3 The biology of beaches is also important. People enjoy whale and dolphin watching, bird watching, shell examining, snorkeling and scuba diving along coastal areas, and many communities will take pride in certain animals that take advantage of local beaches. Sea lions, for example, that bask in the sun on beaches can be a source of local pride in California (Douglass, 2002). Some North Carolina locals also take pride in having sea turtles use their beaches to lay their eggs. Sea birds and fiddler crabs will also use the beach as their home and a source of food. Harming the beaches, as well as the process of beach nourishment, has the potential to impact specific species, and might deprive us of important biodiversity. There are some people who hold the opinion that nourishing the beaches will help keep the animals around by increasing their habitat size. There are others that believe nourishment ruins their natural habitats because nourishment projects can cause dramatic changes in sediment sizes along the beach, and beach structure and hydrology. It is apparent that before nourishment can occur, it is important to understand how beach erosion occurs. B. What causes beach erosion? Beach sands, firstly, are the result of the physical and chemical weathering of continental rocks. The sediments are deposited from land sources; however, once settled on the beach they are not dormant but are constantly changing (OUCT, 1999). There are several major regions of the beach starting from the upper berm down to below the sea level (Diagram I-1). An eroding beach is shown on the left, while an example of a nourished beach can be seen on the right. Worldwide erosion of coastal regions causes major changes in beach profiles. Coastal erosion contributes approximately 0.25x109 tons per year of sediment to the oceans. Two of the largest factors involved in the transport of sediments are grain size and composition. Clay materials are usually small and flakey and will increase the cohesiveness of the sediment making the shear stress necessary to put the sediments in motion greater. Non-cohesive sediments, however, are easier to move and are made up of larger grains. Larger sediments will remain in place while finer grain size is more easily lifted into the water column and can, therefore, be more easily carried out to sea. Sediments of average grain size are the easiest to erode and require slower current speeds to be lifted into suspension. Another important thing to note is that because it is harder to lift fine muds and clays into the water column, they are usually lifted in clumps. This can be a big factor in increasing the rate of erosion (OUCT, 1999). Turbulence is another important factor affecting the movement of sediments. When turbulence increases, there are more frictional interactions among the sediments to lift them and carry them to sea. Flow is not always turbulent, however. It is sometimes laminar (more or less straight) in even sea beds with slow current velocities. However, if the current speed picks up, the flow will become more turbulent right down to the sea bed. When grain size gets to the point where the sediments stick out into the lower sub layer of the water column, eddies begin to