Understanding Our Coastal Environment
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Stability Domains in Barrier Island Dune Systems J
Ecological Complexity 2 (2005) 410–430 http://www.elsevier.com/locate/ecocom Stability domains in barrier island dune systems J. Anthony Stallins * Department of Geography, Florida State University, Room 323 Bellamy Bldg. Tallahassee, FL 32306, USA Received 1 February 2005; received in revised form 12 April 2005; accepted 25 April 2005 Available online 17 October 2005 Abstract Early ecological descriptions of barrier island dune landscapes recognized the importance of biogeomorphic feedbacks and thresholds. However, these dynamics have not been formally linked to complexity theory. In this article, I develop models of dune landscape phase states, or stability domains, based on a synthesis of these prior studies and statistical analyses. Data for these analyses were obtained from compositional and topographic sampling along Sapelo Island, Georgia and South Core Banks, North Carolina. These undeveloped barrier islands are at opposite ends of a regional meteorological gradient in storm- forced overwash disturbance along the southeastern US Atlantic coast. The topography and plant functional group abundances on each island were supportive of earlier studies noting the propensity for distinct self-organizing biogeomorphic feedbacks to emerge along barrier coasts. On South Core Banks, where storm forcings of overwash are more frequent, the recovery processes initiated by burial-tolerant species may reduce topographic resistance to overwash exposure and contagion. On Sapelo Island, a greater abundance of dune-building and burial-intolerant swale species may confer a higher topographic roughness and more resistance to overwash exposure and contagion. Conceptually, the biogeomorphic modifications of overwash forcings on each island perpetuate the habitat conditions and dominant dune plant species in a weak positive feedback. -
Stochastic Dynamics of Barrier Island Elevation
Stochastic dynamics of barrier island elevation Orencio Duran´ Vinenta,1 , Benjamin E. Schafferb, and Ignacio Rodriguez-Iturbea,1 aDepartment of Ocean Engineering, Texas A&M University, College Station, TX 77843-3136; and bDepartment of Civil and Environmental Engineering, Princeton University, Princeton, NJ 08540 Contributed by Ignacio Rodriguez-Iturbe, November 11, 2020 (sent for review June 29, 2020; reviewed by Carlo Camporeale and A. Brad Murray) Barrier islands are ubiquitous coastal features that create low- a marked Poisson process with exponentially distributed marks. energy environments where salt marshes, oyster reefs, and man- The mark of a HWE is defined as the maximum water level groves can develop and survive external stresses. Barrier systems above the beach during the duration of the event and charac- also protect interior coastal communities from storm surges and terizes its size and intensity. This result opens the way for a wave-driven erosion. These functions depend on the existence of probabilistic model of the temporal evolution of the barrier/dune a slowly migrating, vertically stable barrier, a condition tied to elevation, along the lines of the stochastic model of soil moisture the frequency of storm-driven overwashes and thus barrier ele- dynamics (4). The knowledge of the transient probability dis- vation during the storm impact. The balance between erosional tribution function of barrier elevation allows the calculation of and accretional processes behind barrier dynamics is stochastic in after-storm recovery times, overwash probability and frequency, nature and cannot be properly understood with traditional con- and the average overwash transport rate driving the landward tinuous models. Here we develop a master equation describing migration of barriers. -
Natural and Anthropogenic Influences on the Morphodynamics of Sandy and Mixed Sand and Gravel Beaches Tiffany Roberts University of South Florida, [email protected]
University of South Florida Scholar Commons Graduate Theses and Dissertations Graduate School January 2012 Natural and Anthropogenic Influences on the Morphodynamics of Sandy and Mixed Sand and Gravel Beaches Tiffany Roberts University of South Florida, [email protected] Follow this and additional works at: http://scholarcommons.usf.edu/etd Part of the American Studies Commons, Geology Commons, and the Geomorphology Commons Scholar Commons Citation Roberts, Tiffany, "Natural and Anthropogenic Influences on the Morphodynamics of Sandy and Mixed Sand and Gravel Beaches" (2012). Graduate Theses and Dissertations. http://scholarcommons.usf.edu/etd/4216 This Dissertation is brought to you for free and open access by the Graduate School at Scholar Commons. It has been accepted for inclusion in Graduate Theses and Dissertations by an authorized administrator of Scholar Commons. For more information, please contact [email protected]. Natural and Anthropogenic Influences on the Morphodynamics of Sandy and Mixed Sand and Gravel Beaches by Tiffany M. Roberts A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy Department of Geology College of Arts and Sciences University of South Florida Major Professor: Ping Wang, Ph.D. Bogdan P. Onac, Ph.D. Nathaniel Plant, Ph.D. Jack A. Puleo, Ph.D. Julie D. Rosati, Ph.D. Date of Approval: July 12, 2012 Keywords: barrier island beaches, beach morphodynamics, beach nourishment, longshore sediment transport, cross-shore sediment transport. Copyright © 2012, Tiffany M. Roberts Dedication To my eternally supportive mother, Darlene, my brother and sister, Trey and Amber, my aunt Pat, and the friends who have been by my side through every challenge and triumph. -
Barrier Island Migration Sea Level Rise and the Future
Barrier Island Migration stable location and absence of historic inlets in this area suggest that barrier migration may not be a These barrier islands retreated or migrated north- continuous process over timescales of a thousand ward as the ocean continued rising. There is some years or less. Further to the east, the barriers are debate about how the barriers actually moved. more mobile and one can find evidence of barrier Some research suggests that the barriers slowly island rollover processes such as old flood shoals drowned in place and then “jumped” or “skipped” in the bay that were associated with inlets that have landward to a new position coinciding with the new opened and closed naturally over the last several position of the shoreline. More recent studies indi- hundred years. cate the islands move in a more continuous process where sand is transported across the island from the ocean to the bay, allowing the island to migrate Sea Level Rise and the Future landward. There are three primary ways that sand can be transported across a barrier island: inlet Along the New York coast, sea level is not only ris- formation, overwash processes and eolian (or wind) ing, the land is also slowly sinking, or subsiding due transport. On Long Island’s south shore, the inlets to geologic processes. The rise in the water level in are actually far more important than either over- relation to the land surface due to the sinking of the washes or the wind in terms of moving sand land- land and the raising of the sea is known as relative ward and driving barrier migration. -
HISTORICAL HURRICANES in SOUTH CAROLINA September 10-22, 1989 N Average, South Carolina Experiences a Land-Falling Hurricane Hurricane Hugo Every Seven Years
HISTORICAL HURRICANES IN SOUTH CAROLINA September 10-22, 1989 n average, South Carolina experiences a land-falling hurricane Hurricane Hugo every seven years. Between 1900 and 2000, 14 hurricanes Time of Landfall: 12 a.m., 9/22/1989 Saffir/Simpson Scale Category: Category 4 Omade landfall along the coast of South Carolina including three Location of Landfall: Sullivans Island, SC Estimated U.S. Damage Costs: $7 billion major hurricanes: Hurricane Hugo (1989), Hurricane Gracie (1959), Maximum Winds at Landfall: 140 mph Estimated U.S. Deaths: 49 and Hurricane Hazel (1954). These South Carolina hurricanes made the Minimum Pressure at Landfall: 27.58” (934 mb) Estimated Storm Surge: 18-20 feet Top 40 Most Intense Hurricanes in a study by scientists at the National Hurricane Center. Rankings were based on minimum central pressures SUMMARY at the time of landfall. Hugo ranked #11 on the list, followed by Hazel Hugo originated off the coast of western Africa near the Cape Verde Islands as a tropical disturbance on September 9th and quickly gained strength to a tropical storm on the 11th and hurricane on the 13th. Hugo reached maximum intensity at Category 5 on the 15th with winds estimated at 160 mph and a minimum pressure of 918 mb east of the Leeward Islands. at #13, and Gracie at #33. Although major hurricanes are rare for the The hurricane passed directly over the islands of Guadaloupe, St. Croix, and Puerto Rico over the next few days before heading northwestward toward the South Carolina coast. By 6 a.m. coastal sections of South Carolina, averaging one every 25 years, the EDT on September 21, 1989, hurricane warnings were issued for coastal South Carolina and more than 250,000 people evacuated the coast. -
Types and Causes of Beach Erosion Anomaly Areas in the U.S. East Coast Barrier Island System: Stabilized Tidal Inlets
Middle States Geographer, 2007, 40:158-170 TYPES AND CAUSES OF BEACH EROSION ANOMALY AREAS IN THE U.S. EAST COAST BARRIER ISLAND SYSTEM: STABILIZED TIDAL INLETS Francis A. Galgano Jr. Department of Geography and the Environment Villanova University 800 Lancaster Avenue Villanova, Pennsylvania 19085 ABSTRACT: Contemporary research suggests that most U.S. beaches are eroding, and this has become an important political and economic issue because beachfront development is increasingly at risk. In fact, the Heinz Center and Federal Emergency Management Agency (FEMA) estimate that over the next 60 years, beach erosion may claim one out of four homes within 150 meters of the U.S. shoreline. This is significant because approximately 350,000 structures are located with 150 meters of the shoreline in the lower 48 states, not including densely populated coastal cities such as New York and Miami. Along the East Coast, most beaches are eroding at 1 to 1.5 meters per year. However, beach erosion is especially problematic along so-called beach erosion anomaly areas (EAAs) where erosion rates can be as much as five times the rate along adjacent beaches. Identifying and understanding these places is important because property values along U.S. East Coast barrier islands are estimated to be in the trillions of dollars, and the resultant beach erosion may also destroy irreplaceable habitat. There are a number of factors⎯natural and anthropogenic⎯that cause beaches to erode at anomalous rates. This paper will focus on the barrier island system of the U.S. East Coast, classify beach EAAs, and examine beach erosion down drift from stabilized tidal inlets because they are perhaps the most spatially extensive and destructive EAAs. -
CLASSIFICATION of CALIFORNIA ESTUARIES BASED on NATURAL CLOSURE PATTERNS: TEMPLATES for RESTORATION and MANAGEMENT Revised
CLASSIFICATION OF CALIFORNIA ESTUARIES BASED ON NATURAL CLOSURE PATTERNS: TEMPLATES FOR RESTORATION AND MANAGEMENT Revised David K. Jacobs Eric D. Stein Travis Longcore Technical Report 619.a - August 2011 Classification of California Estuaries Based on Natural Closure Patterns: Templates for Restoration and Management David K. Jacobs1, Eric D. Stein2, and Travis Longcore3 1UCLA Department of Ecology and Evolutionary Biology 2Southern California Coastal Water Research Project 3University of Southern California - Spatial Sciences Institute August 2010 Revised August 2011 Technical Report 619.a ABSTRACT Determining the appropriate design template is critical to coastal wetland restoration. In seasonally wet and semi-arid regions of the world coastal wetlands tend to close off from the sea seasonally or episodically, and decisions regarding estuarine mouth closure have far reaching implications for cost, management, and ultimate success of coastal wetland restoration. In the past restoration planners relied on an incomplete understanding of the factors that influence estuarine mouth closure. Consequently, templates from other climatic/physiographic regions are often inappropriately applied. The first step to addressing this issue is to develop a classification system based on an understanding of the processes that formed the estuaries and thus define their pre-development structure. Here we propose a new classification system for California estuaries based on the geomorphic history and the dominant physical processes that govern the formation of the estuary space or volume. It is distinct from previous estuary closure models, which focused primarily on the relationship between estuary size and tidal prism in constraining closure. This classification system uses geologic origin, exposure to littoral process, watershed size and runoff characteristics as the basis of a conceptual model that predicts likely frequency and duration of closure of the estuary mouth. -
Hurricane & Tropical Storm
5.8 HURRICANE & TROPICAL STORM SECTION 5.8 HURRICANE AND TROPICAL STORM 5.8.1 HAZARD DESCRIPTION A tropical cyclone is a rotating, organized system of clouds and thunderstorms that originates over tropical or sub-tropical waters and has a closed low-level circulation. Tropical depressions, tropical storms, and hurricanes are all considered tropical cyclones. These storms rotate counterclockwise in the northern hemisphere around the center and are accompanied by heavy rain and strong winds (NOAA, 2013). Almost all tropical storms and hurricanes in the Atlantic basin (which includes the Gulf of Mexico and Caribbean Sea) form between June 1 and November 30 (hurricane season). August and September are peak months for hurricane development. The average wind speeds for tropical storms and hurricanes are listed below: . A tropical depression has a maximum sustained wind speeds of 38 miles per hour (mph) or less . A tropical storm has maximum sustained wind speeds of 39 to 73 mph . A hurricane has maximum sustained wind speeds of 74 mph or higher. In the western North Pacific, hurricanes are called typhoons; similar storms in the Indian Ocean and South Pacific Ocean are called cyclones. A major hurricane has maximum sustained wind speeds of 111 mph or higher (NOAA, 2013). Over a two-year period, the United States coastline is struck by an average of three hurricanes, one of which is classified as a major hurricane. Hurricanes, tropical storms, and tropical depressions may pose a threat to life and property. These storms bring heavy rain, storm surge and flooding (NOAA, 2013). The cooler waters off the coast of New Jersey can serve to diminish the energy of storms that have traveled up the eastern seaboard. -
Dear Investors As You May Might Have Heard from Different Media Outlets
Dear investors As you may might have heard from different media outlets, the east coast of the U.S. is facing a potential threat of landfall of the major hurricane named Florence in the coming days. The storm is currently about 385 miles/620 KM southwest of BERMUDA and about 625 miles/1005 KM southeast of Cape Fear North CAROLINA, moving to the direction of North and South Carolina. The intensity is currently Cat 4, with maximum sustained wind speed very close to 140 mph. As the storm moves to the coast, the wind will intensify to Cat 5 and maximum sustained winds can reach 155 mph. Timing is more difficult to predict now as many meteorologists suggest Florence will slow on approach to the coast, with a possible stalling that could exacerbate the impacts for the area it nears the shore. Catastrophe risk modeller RMS said, “Florence will be the strongest hurricane to make landfall over North Carolina since Hazel in 1954 – this would be a major event for the insurance industry. As with all hurricanes of this intensity, Florence poses significant impacts due to damaging hurricane-force winds and coastal storm surge, but inland flooding is becoming an increasing threat. Forecasts include the possibility of Florence slowing down after landfall and causing as much as 20 inches of rain in the Carolinas. While very significant, this remains much lower than the amount of rainfall observed last year during Hurricane Harvey.” Wind Florence is expected to make landfall as a hurricane between Cat 3 and Cat 4. The wind speed can reach 110-130 mph and central pressure is estimated 962mb. -
Coastal Geology of the Holocene Progradant Plains of Sandy Beach
Quaternary and Environmental Geosciences (2021) 12(1):1-17 Coastal geology of the Holocene progradant plains of sandy beach ridges in Santa Catarina state, Southeastern Brazil Geologia costeira das planícies progradantes holocênicas de cordões litorâneos arenosos no estado de Santa Catarina, sul do Brasil Norberto Olmiro Horn Filho Universidade Federal de Santa Catarina [email protected] Abstract Beach ridges are indicators of supratidal and intertidal depositional environments built by waves. The major factors that influence on the ridge’s formation is related to antecedent topography, sediment supply, sedimentary balance, and substrate gradient. They consist of siliciclastic and/or bioclastic sediments whose grain size varies from very coarse sand to very fine sand. At Santa Catarina state, progradant plains are related to Pleistocene and Holocene regressive marine processes. The Holocene marine terraces, object of this study, predominate in the coastal plains of Passo de Torres, Pinheira, Jurerê, Tijucas and Navegantes, presenting heights from 3 to 6 m in elevations and 1 to 2 m in depressions. The ridge deposits are constituted by sandy sediments, medium to very fine, composed by quartz, opaque and heavy minerals and shell fragments. The runnel deposits comprehend silt-sand-clayey sediments enriched by organic matter. The evolution of Holocene Santa Catarina beach ridges is connected to the regressive events occurred after 5,1 ky BP that indicate the position of paleo coastlines and mean sea level of the Holocene. Key words: Geomorphology; Sedimentology; Coastal evolution. Resumo Os cordões regressivos são indicadores de ambientes deposicionais formados por ondas sob regime de supra e intermarés. Os fatores mais relevantes que influenciam na formação dos cordões estão relacionados à topografia antecedente, suprimento sedimentar, balanço sedimentar e gradiente do substrato. -
BARRIER ISLAND STATUS REPORT Fiscal Year 2020 Annual Plan
BARRIER ISLAND STATUS REPORT Fiscal Year 2020 Annual Plan In compliance with Act 297 of the 2006 Regular Legislative Session, the Coastal Protection and Restoration Authority (CPRA) provides this barrier island status report as part of the Annual Plan document, which will be submitted to each member of the Louisiana Legislature. The current Barrier Island Status report is available electronically at the CPRA website. Please visit www.coastal.LA.gov to download and review the full report. A summary of the report is provided below. CONSTRUCTED PROJECTS The coastlines of the modern Mississippi River delta plain are bordered by numerous barrier islands from Raccoon Island in the west to Hewes Point in the northern Chandeleur Islands (Figure 1). These barrier islands could be grouped to represent fragmented remnants of distal extremities of several major delta lobes and headlands: to identify these barrier islands with their respective delta lobes they have been grouped from west to east as the Early Lafourche Delta System, Late Lafourche Delta System, Modern Delta System, and the St. Bernard Delta System. The back- barrier lagoons are connected to the Gulf of Mexico by approximately 25 tidal inlets which separate these barrier islands from each other and allow the exchange of diurnal tides. Figure 1: Location of barrier islands belonging to Early Lafourche, Late Lafourche, Modern, and St. Bernard barrier island systems in Louisiana The restoration of Louisiana’s barrier islands and barrier island systems has been a priority for a number of restoration programs over the past several decades and over 40 barrier island projects have been constructed to date (including 13 in the Early Lafourche Delta System, 18 in the Late Lafourche Delta System, 9 in the Modern Delta System, and 2 in the St. -
EGU2009-7028-1, 2009 EGU General Assembly 2009 © Author(S) 2009
Geophysical Research Abstracts, Vol. 11, EGU2009-7028-1, 2009 EGU General Assembly 2009 © Author(s) 2009 Sea-level proxies extracted from GPR reflection data collected across recently formed berm, beach ridge and swale deposits on the island of Anholt, Denmark L. Nielsen and L. B. Clemmensen University of Copenhagen, Department of Geography and Geology, Copenhagen K, Denmark ([email protected]) GPR reflection data have been collected across the most recent part of a berm, beach ridge and swale system formed during the last 130 years on the northern coast of the island of Anholt, the Kattegat, Denmark. The reflected arrivals have a peak frequency of about 250 MHz and they image the subsurface with a vertical resolution of 0.1–0.2 m to a maximum depth of 5 m below the surface. The berm and beach ridges with maximum heights of about 1.8 m and 1.5 m, respectively, appear as mounded features in the GPR sections. The berm ridge also contains low-angle, seaward dipping reflections. Similar sea-ward dipping reflections are also observed below swales, and current swale surfaces appear to constitute erosion surfaces. Reflections downlapping on a package of reflections, which is interpreted to be representative of upper shoreface deposits, are suggested to constitute good proxies of sea level. Tamura et al. (2008) suggested that similar downlapping reflections may represent a depth level of about 1 m below the mean sea level based on investigations of the Kujukuri strand plain in eastern Japan. We have made 17 depth readings of such downlaps along our 159-m-long profile.