Overwash Fans Research Articles

Impact of Hurricane Harvey on the Upper Texas Coast: Using Airborne Lidar Data Sets with UAV-Derived Topographic Data to Monitor Change and Track Recovery

The frequency of hurricanes and tropical storms is increasing; for example, there were a record-breaking 31 named storms during the 2020 Atlantic hurricane season. Texas has historically been susceptible to hurricanes and tropical storms; however, Hurricane Harvey in 2017 was the highest category storm event to cross Texas since 2000. Our regional change analysis used 2016 and 2018 lidar-derived elevation models with 1 m spatial resolution to determine above-sea level changes due to Hurricane Harvey. The upper Texas coast experienced shoreline erosion, with local depositional events occurring on the southeastern sides of jetties and groins. Incidents of dune washout and overwash fans were present along the barrier islands of the upper Texas coast, as well as erosion to foredune complexes and a decrease in dune heights. As of March 2018, recovery is visible through berm buildup and backbeach aggradation. Our multiyear analysis (above sea level) of four sites within Galveston and Follett’s Islands determined the immediate impact of Harvey (2016–2017) and followed recovery until March 2019. The multiyear analysis determined that all four sites experienced varying levels of recovery by 2018. UAV surveys conducted in 2022 showed potential in acquiring topographic data for comparison with 2019 beach-dune conditions.

Nature versus Humans in Coastal Environmental Change: Assessing the Impacts of Hurricanes Zeta and Ida in the Context of Beach Nourishment Projects in the Mississippi River Delta

Hurricanes are one of the most devastating earth surface processes. In 2020 and 2021, Hurricanes Zeta and Ida pounded the Mississippi River Delta in two consecutive years, devastated South Louisiana, and raised tremendous concerns for scientists and stakeholders around the world. This study presents a high-resolution spatial-temporal analysis incorporating planialtimetric data acquired via LIDAR, drone, and satellite to investigate the shoreline dynamics near Port Fourchon, Louisiana, the eye of Ida at landfall, before and after the beach nourishment project and recent hurricane landfalls. The remote sensing analysis shows that the volume of the ~2 km studied beachfront was reduced by 240,858 m3 after consecutive landfalls of Hurricanes Zeta and Ida in 2020 and 2021, while 82,915 m3 of overwash fans were transported to the backbarrier areas. Overall, the studied beach front lost almost 40% of its volume in 2019, while the average dune crest height was reduced by over 1 m and the shoreline retreated ~60 m after the two hurricane strikes. Our spatial-temporal dataset suggests that the Louisiana Coastal Protection and Restoration Authority’s (CPRA’s) beach nourishment effort successfully stabilized the beach barrier at Port Fourchon during the hurricane-quiescent years but was not adequate to protect the shoreline at the Mississippi River Delta from intense hurricane landfalls. Our study supports the conclusion that, in the absence of further human intervention, Bay Champagne will likely disappear completely into the Gulf of Mexico within the next 40 years.

Coastal erosion and sediment reworking caused by hurricane Irma – implications for storm impact on low‐lying tropical islands

AbstractHurricane Irma (September 2017) was one of the most devastating hurricanes in recent times. In January 2018, a post‐hurricane field survey was conducted on Anegada (British Virgin Islands) to report on the erosional and depositional evidence caused by Hurricane Irma's storm surge and waves. We document the type and extent of hurricane‐induced geomorphological changes, allowing for an improved risk assessment of hurricane‐related inundation on low‐lying islands and carbonate platforms.Anegada's north shore was most impacted by Hurricane Irma. The surge reached about 3.8 m above sea level and onshore flow depths ranged between 1.2 to 1.6 m. Storm wave action created 1 to 1.5 m high erosional scarps along the beaches, and the coastline locally retreated by 6 to 8 m.Onshore sand sheets reached up to 40 m inland, overlie a sharp erosive contact and have thicknesses of 7 to 35 cm along the north shore. In contrast, lobate overwash fans in the south are 2 to 10 cm thick and reach 10 to 30 m inland.Moreover, the hurricane reworked a pre‐existing coast‐parallel coral rubble ridge on the central north shore. The crest of the coral rubble ridge shifted up to 10 m inland due to the landward transport of cobbles and boulders (maximum size 0.5 m3) that were part of the pre‐hurricane ridge.A re‐survey, 18 months after the event, assessed the degree of the natural coastal recovery. The sand along the northern shoreline of Anegada that was eroded during the hurricane and stored in the shallow water, acted as a nearshore source for beach reconstruction which set in only days after the event. Beach recovery peaked in February 2018, when beaches accreted within hours during a nor'easter‐like storm that transported large volumes of nearshore sand back onto the beach.

Intermittent Retreat Behavior in Experimental Barrier Island Response to Constant Sea Level Rise and Wave Forcing

AbstractBarrier islands are naturally low‐lying features and are susceptible to drowning from sea level rise. However, previous work suggests that barrier islands can retreat upslope to maintain their subaerial extent, though not necessarily at a constant rate even under steady forcing. To explore this idea, we performed physical experiments where barrier islands were subjected to a constant relative sea level rise (RSL) and a constant wave environment. We tracked the islands through time with overhead images and periodic laser elevation scans. Time series of island location show that the islands did not retreat at constant rates through the transgression. Rather, overall long‐term retreat occurred through a punctuated retreat motion comprising steady retreat alternating with accelerated steps. The source of this complex behavior is a cycling between two morphologies: one where an island has a developed ridge and another where no ridge is present. Sea level rise allows waves to overtop the island and erode the ridge that once kept the waves at bay. That sediment is deposited behind the island, moving the barrier landward. Waves continue to push sediment back toward the mainland until the island becomes too wide for waves to carry sediment across the island. This begins a process of backfilling the overwash fan, eventually creating a new ridge. These simple experiments support previous theoretical suggestions that periodic overwash is a key part of a barrier island's behavior during a transgression, and that this can lead to punctuated retreat even when RSL rise is steady.

Stormtools Design Elevation (SDE) Maps: Including Impact of Sea Level Rise

Many coastal communities in the US use base flood elevation (BFE) maps for the 100-year return period, specified on Federal Emergency Management Agency (FEMA) Flood Insurance Rate Maps (FIRMs), to design structures and infrastructure. The FIRMs are increasingly known to have serious problems in accurately specifying the risk coastal communities face, as most recently evidenced during hurricanes Harvey and Irma in 2017 and Florence and Michael in 2018. The FIRM BFE maps also do not include the impact of sea level rise, which clearly needs to be considered in the design of coastal structures over the next several decades given recent National Oceanic and Atmospheric Administration (NOAA) sea level rise (SLR) projections. Here, we generate alternative BFE maps (STORMTOOLS Design Elevation (SDE) maps) for coastal waters of Rhode Island (RI) using surge predictions from tropical and extratropical storms of the coupled surge-wave models from the US Army Corp of Engineers, North Atlantic Comprehensive Coast Study (NACCS). Wave predictions are based on application of a steady state, spectral wave model (STWAVE), while impacts of coastal erosion/accretion and changes of geomorphology are modeled using XBeach. The high-resolution application of XBeach to the southern RI shoreline has dramatically increased the ability to represent the details of dune erosion and overtopping and the associated development of surge channels and over-wash fans and the resulting landward impact on inundation and waves. All methods used were consistent with FEMA guidelines for the study area and used FEMA-approved models. Maps were generated for 0, 2 ft (0.6 m), 5 ft (1.5 m), 7 ft (2.1 m), and 10 ft (3.1 m) of sea level rise, reflecting NOAA high estimates at various times for the study area through 2100. Results of the simulations are shown for both the southern RI shoreline (South Coast) and Narragansett Bay, to facilitate communication of projected BFEs to the general public. The maps are hosted on the STORMTOOLS ESRI Hub to facilitate access to the data. They are also now part of the RI Coastal Resources Management Council (CRMC) risk-based permitting system. The user interface allows access to all supporting data including grade elevation, inundation depth, and wave crest heights as well as corresponding FEMA FIRM BFEs and associated zones.

Deer do not affect short-term rates of vegetation recovery in overwash fans on Fire Island after Hurricane Sandy.

Coastal resilience is threatened as storm‐induced disturbances become more frequent and intense with anticipated changes in regional climate. After severe storms, rapid recovery of vegetation, especially that of dune‐stabilizing plants, is a fundamental property of coastal resilience. Herbivores may affect resilience by foraging and trampling in disturbed areas. Consequently, assessing the impacts of herbivores on recovering vegetation is important for coastal land management.We combined imagery classification, wildlife monitoring, and trend analysis to investigate effects of white‐tailed deer on recovery rates of vegetation four years poststorm in nine overwashed areas. We estimated local deer density with trail cameras, how it relates to an index of primary productivity, and assessed the relationship between deer density and rates of vegetation recovery in overwash fans.Prestorm vegetation cover consisted of shrubs and sporadic patches of beach grass. Poststorm cover was dominated by beach grass. At current rates, vegetation coverage will return to prestorm conditions within the decade, though community transition from grasses to shrubs will take much longer and will vary by site with dune formation.The effect of deer on rates of vegetation recovery was negative, but not statistically significant nor biologically compelling. Although effects of deer trampling on beach grass are evident in classified imagery, deer foraging on beach grass had little effect on its rate of spread throughout overwash fans.While the rate of spread of the primary dune‐building grass was not deleteriously affected by deer, locally high deer densities will likely affect the future establishment and development of herbs and shrubs, which are generally more palatable to deer than beach grass.

Effects of white-tailed deer (Odocoileus virginianus) exclusion on plant recovery in overwash fans after a severe coastal storm.

We documented the impacts of an abundant deer population on dune vegetation recovering from severe storm surge on a barrier island through use of permanent plots and a repeated measures analysis. Three years after landfall of the storm, vegetation cover was dominated by American beachgrass, Ammophila breviligulata, though we observed 12 plant species among plots surveyed. We documented significantly greater vegetation cover in fenced than unfenced plots in overwash fans in two consecutive years. The difference in species richness between fenced and unfenced plots was significant, though richness was consistently low (≤4 species per plot) and we did not detect a statistically significant difference between years. Both deer trampling and foraging effects were captured in this study, though separation between these effects was not possible. Because trampling effects are often exacerbated on sandy soils, trampling and foraging effects should be isolated and investigated in future assessments of deer impacts on coastal vegetation. Managing deer to lower abundance may enhance coastal resilience if vegetation is allowed to recover unimpeded by foraging and trampling, though a better understanding of the precise nature of deer impacts on dune vegetation is necessary.

Sedimentary architecture and depositional controls of a Holocene wave‐dominated barrier‐island system

AbstractBarrier‐island system evolution is controlled by internal and external forcing mechanisms, and temporal changes in these mechanisms may be recorded in the sedimentary architecture. However, the precise role of individual forcing mechanisms is rarely well understood due to limited chronological control. This study investigates the relative role of forcing conditions, such as antecedent topography, sea‐level rise, sediment supply, storms and climate changes, on the evolution of a Holocene wave‐dominated barrier‐island system. This article presents temporal reconstruction of the depositional history of the barrier‐island system of Rømø in the Wadden Sea in unprecedented detail, based on ground‐penetrating radar profiles, sediment cores, high‐resolution dating and palynological investigations, and shows that ca 8000 years ago the barrier island formed on a Pleistocene topographic high. During the initial phase of barrier evolution, the long‐term sea‐level rise was relatively rapid (ca 9 mm year−1) and the barrier was narrow and frequently overwashed. Sediment supply kept pace with sea‐level rise, and the barrier‐island system mainly aggraded through the deposition of a ca 7 m thick stack of overwash fans. Aggradation continued for ca 1700 years until sea‐level rise had decreased to <2 mm year−1. In the last ca 6000 years, the barrier prograded 4 to 5 km through deposition of a 10 to 15 m thick beach and shoreface unit, despite a long‐term sea‐level rise of 1 to 2 mm year−1. The long‐term progradation was, however, interrupted by a transgression between 4000 years and 1700 years ago. These results demonstrate that the large‐scale morphology of the Danish Wadden Sea shoreline influences the longshore sediment transport flux and the millennial‐scale dispersal of sediment along the shoreline. On decadal to centennial timescales, major storms induced intense beach and shoreface erosion followed by rapid recovery and progradation which resulted in a highly punctuated beach and shoreface record. Major storms contributed towards a positive sediment budget, and the sustained surplus of sediment was, and still is, instrumental in maintaining the aggradational–progradational state of the barrier island.

Storm erosion during the past 2000 years along the north shore of Delaware Bay, USA

The recent impacts of tropical cyclones and severe storms on the U.S. Atlantic coast brought into focus the need for extended records of storm activity from different geomorphologic settings. Such reconstructions are typically developed from sites that experienced repeated overwash of sand into low-energy, depositional environments. However, salt-marsh sediment may also preserve a record of repeated erosion from tropical cyclones and storms. We describe late Holocene sediments beneath the Sea Breeze salt marsh (Delaware Bay, New Jersey) from more than 200 gouge cores positioned along seven transects. The stratigraphic record documents at least seven depositional sequences consisting of salt-marsh peat and mud couplets that represent dramatic changes in sedimentation regime. There are a number of processes that could produce these stratigraphic sequences against a background of rising relative sea level including: lateral migration of tidal creeks; tidal channel network and/or drainage ditch expansion; changes in sediment delivery rates; rapid relative sea-level change; tsunami; and formation of salt pans. The abrupt contacts between the salt-marsh peat and overlying intertidal mud suggest that erosion of the peat was followed by rapid infilling of accommodation space. Correlation of erosional surfaces across 2.5km suggests a common mechanism and we propose that the erosion was caused by tropical cyclones and/or storms. We developed a chronology of repeated salt-marsh erosion and recovery using 137Cs, metal pollution (Pb concentration and stable isotopes), and radiocarbon data. Two recent episodes of salt-marsh erosion may correlate with historic tropical cyclones in AD 1903, and AD 1821/1788 that impacted the Atlantic coast of New Jersey, but the erosive nature of the Sea Breeze site hinders definitive correlation. Prehistoric erosional sequences correlate with overwash fans preserved in the regional sedimentary record. We estimated that it takes from several decades to almost 200years for salt-marshes to recover from storm erosion.

Restoration of overwash processes creates piping plover (Charadrius melodus) habitat on a barrier island (Assateague Island, Maryland)

On Assateague Island, an undeveloped barrier island along Maryland and Virginia, a foredune was constructed to protect the island from the erosion and breaching threat caused by permanent jetties built to maintain Ocean City Inlet. Scientists and engineers integrated expertise in vegetation, wildlife, geomorphology, and coastal engineering in order to design a habitat restoration project that would be evaluated in terms of coastal processes rather than static features. Development of specific restoration targets, thresholds for intervention, and criteria to evaluate long-term project success were based on biological and geomorphological data and coastal engineering models. A detailed long-term monitoring plan was established to measure project sustainability. The foredune unexpectedly acted as near-total barrier to both overwash and wind, and the dynamic ecosystem underwent undesirable habitat changes including conversion of early-succession beach habitat to herbaceous and shrub communities, diminishing availability of foraging habitat and thereby reducing productivity of the Federally-listed Threatened Charadrius melodus (piping plover). To address these impacts, multiple notches were cut through the constructed foredune. The metric for initial geomorphological success—restoration of at least one overwash event per year across the constructed foredune, if occurring elsewhere on the island—was reached. New overwash fans increased island stability by increasing interior island elevation. At every notch, areas of sparse vegetation increased and the new foraging habitat was utilized by breeding pairs during the 2010 breeding season. However, the metric for long-term biological success—an increase to 37% sparsely vegetated habitat on the North End and an increase in piping plover productivity to 1.25 chicks fledged per breeding pair—has not yet been met. By 2010 there was an overall productivity of 1.2 chicks fledged per breeding pair and a 1.7% decrease in sparsely vegetated habitat. Ideally, overwash restoration will sustain the availability of foraging habitat, but future foredune modifications may be necessary to maintain or increase overwash processes and piping plover habitat in the project area.

Restoring Beaches for Atlantic Coast Piping Plovers (Charadrius melodus): A Classification and Regression Tree Analysis of Nest‐Site Selection

To effectively restore wildlife habitat, ecological research must be easily translated into practical design criteria. Clear directives from research can support arguments that promote more appropriate restoration strategies. For the federally threatened piping plover (Charadrius melodus), beach stabilization practices often accelerate the degradation of suitable breeding habitat and could be revised to provide more advantageous conditions. Several studies of piping plover habitat selection have been conducted, yet useful and detailed design directives remain undeveloped. In this study, we use classification and regression tree analysis to (1) identify microhabitat characteristics and important variable interactions leading to nest establishment and (2) develop target, trigger, and threshold values for use in effective design and adaptive management of piping plover habitat. We found that nests primarily occur in three distinct habitat conditions defined by percent shell and pebble cover, vegetative cover, and distance to nearest dunes and the high tide line. Nest‐site characteristics vary depending on where in the landscape a nest is initiated (backshore, overwash fan, or primary dune). We translate these results into the following pragmatic target design parameters: (1) vegetative cover: less than 10% (backshore), 13% (primary dune); (2) shell/pebble cover: 17–18%; (3) dune height: ≤1.1 m; and (4) dune slope: ≤13%. We also recommend threshold values for adaptive management to maintain habitat that is attractive to plovers. This technique can be applied to many other wildlife habitat restorations. Future studies on niche parameters driving chick survival are necessary to realize the full potential of habitat restoration in increasing overall reproductive success.

Fifty-One Years of Shoreline Change at Little Lagoon, Alabama

In Alabama the term "coastal shoreline" applies to the Gulf shoreline and the shorelines of estuaries, bays, and sounds connected to the Gulf of Mexico and subject to its tides. However, Alabama shoreline studies have yet to include Little Lagoon, which has been connected to the Gulf of Mexico for most of the last 200 years according to historical charts. This study presents an analysis of shoreline change on Little Lagoon based on aerial photographs dating from 1955 to 2006. All images were georeferenced, projected, and digitized in a Geographic Information System to create sliver polygons that represented areas of change. The net change in lagoon size between 1955 and 2006 was relatively small (-0.4 percent), but significant changes occurred when evaluated on a larger scale. The greatest changes to Little Lagoon were found on its southern shoreline near tidal inlets, human development, and hurricane over-wash fans.

Sediment Spatial Patterns in a Hurricane Katrina Overwash Fan on Dauphin Island, Alabama, U.S.A.

Abstract Hurricane Katrina scoured the seaward side of Dauphin Island, Alabama, and then deposited the sediment on the back side of the island into a repeating pattern of arc-shaped overwash fans. We set out to determine if sediment sorting operated at the scale of the individual overwash fan during the storm. Variograms and kriging were used to create maps of the topography and sediment patterning in terms of the mean grain size, standard deviation, skewness, and mineral composition. Mantel tests were used to correlate hypothesized directional processes with the patterns. We found that sands near the surface were spatially sorted in a direction consistent with the north-northwesterly forces of Katrina. The spatial distribution was not correlated with the topography. Our results support the concept that horizontal spatial pattern formation primarily begins as the extreme forces of a hurricane subside.

Volumetric Analysis of Overwash Fans Resulting from Tropical Storms on North Hatteras Island, North Carolina

In 1999, Hurricanes Dennis, Floyd, and Irene affected the North Carolina coastline. Although none of these storms made landfall north of Cape Hatteras, the northern Hatteras Island shoreline suffered severe beach erosion and widespread overwash. The volume of three overwash fans located within a 3.75 km section of shoreline in Rodanthe was determined by measuring depth of deposition at selected locations on the fans. Fan area was determined from measurements taken from aerial photographs. The depths of deposition on the fans ranged from 0.2-1.2m, and 30-50m3 per meter length of fan were deposited at the sites. The volumes deposited exceed the amounts recorded during previous storms at locations along the U.S. East Coast. Subaerial sedimentation on barrier islands depends on high magnitude/low frequency events because their higher storm surge and wave heights produce dune breaching. Overwash is not widespread during lower magnitude storms because the water levels are not high enough to result in flow across the barrier. The total volume of overwash on North Hatteras Island was estimated from fan areas measured on aerial photographs in conjunction with the average depth of deposition measured on the Rodanthe fans. The total amount of sediment deposited was estimated to be 48 m3 per meter of fan length. Comparing these overwash volumes to amounts deposited by wind on the barrier island north of Hatteras Island shows that, on an annual basis, overwash far exceeds wind as a mechanism for transferring sediment inland. However, an extrapolation over a longer period to accommodate for temporal variations reveals that the volumes of sediment transferred by overwash and by wind are nearly balanced.

A backbarrier overwash record of intense storms from Brigantine, New Jersey

Analysis of aerial photographs and historic charts indicates that the barrier beach at Brigantine, NJ has migrated landward 300 to 400 m since 1869, primarily as a result of overwash during hurricanes and winter storms. A series of vibracores from the backbarrier salt marsh reveals a millennial-scale stratigraphic record of overwash deposition. Carbon-14 (C-14) and Cesium-137 (Cs-137) radioisotopic methods were used to date overwash deposits (washovers). The ages of recent washovers are consistent with deposition during intense storms in 1938, 1944, 1950, and 1962. An additional overwash deposit recovered in five of the sediment cores was likely deposited by an intense hurricane strike in 1821 or possibly in 1788. Two prehistoric overwash fans were likely deposited by intense storms striking the New Jersey Coast in the 7th to 14th centuries and 6th to 7th centuries A.D. The landward barrier migration indicates that the older overwash sediments were likely transported a considerably greater distance than the more recent overwash fans. The greater distance of transport may indicate that the prehistoric storms that deposited overwash fans across the study site were more intense than the most intense storm to strike this coast in the historic period, the hurricane of 1821. The spatially variable occurrence of overwash deposition at this site points to a need for multisite stratigraphic surveys of extensive stretches of the coast in order to develop reliable records of past intense storm frequency from backbarrier environments.

Total sediment budget of a transgressive barrier-spit, Skallingen, SW Denmark: A review

Average sea-level rise in the northern part of the Danish Wadden Sea has been 1.3 mm a−1 during the last 100 years but during the last 25 years a rise of 4.2 mm a−1 was observed. Concurrent with the recent sea-level rise the Skallingen barrier spit has migrated landward by 3–5 m a−1. Long term sediment budgets for each of the morphological units involved in the migration are reviewed (e.g. onshore in the shore face +90.000 m3 a−1, longshore -641.000 m3 a−1, foredunes +65,000 m3 a−1, overwash fan including shorenormal dunes +11,000 m3 a−1, spit terminus -96,000 m3 a−1, tidal flat + 10,000 m3 a−1 and backbarrier salt marsh +33,000 m3 a−1) and used to establish the relative importance of sediment transport processes involved in barrier migration. Strong interannual variations exist in the long term budget making evaluation of barrier behaviour based on short term measurements doubtful. In a cross shore sense the barrier spit is accreting in spite of the sea level rise. This is specially pronounced at an active overwash fan. However, due to substantial sediment losses to longshore transport the barrier, gets narrower and shorter during its transgressive behaviour. This may indicate that preservation of barriers in the geological record during rapid sea level rise is promoted when sediment loss to longshore transport is insignificant.

On the Erosive Trail of A 14Th and 15Th Century Hurricane in Connecticut (Usa) Salt Marshes

This paper examines if an erosive hiatus found in the peat stratigraphy and marsh-accumulation record from northwest Hammock River Marsh (HRM), Connecticut (CT) can be attributed to a 14th or a 15th century hurricane, each documented by a radiocarbon-dated overwash fan in Succotash Marsh (SM) (Rhode Island) about 90 km to the east. Given that (i) the best estimate age range for the 15th century overwash deposit in SM (1400–1440 cal AD, 2 σ) overlaps entirely with that for first plant growth after erosion at HRM (1390–1450 cal AD, 2 σ), while the best estimate age range for the 14th century overwash deposit (1290–1410 cal AD, 2 σ) overlaps just 10 yr, and (ii) interpretation of the available stratigraphic and sedimentary evidence from HRM suggests that a high-energy event offers the simplest explanation for the observed marsh erosion, we conclude that a plausible link exists between the 15th century hurricane and the marsh erosion in HRM. The best estimate age range for the 14th century hurricane appears to overlap for 91% with the age range for the first plant growth (1290–1400 cal AD, 2 σ) following marsh erosion in East River Marsh (CT), located about 12 km west of HRM. These results imply that erosive boundaries in salt-marsh peat deposits have potential as markers of past hurricane activity.

700 yr sedimentary record of intense hurricane landfalls in southern New England

Five intense (category 3 or greater) hurricanes occurring in 1635, 1638, 1815, 1869, and 1938 have made landfall on the New England coast since European settlement. Historical records indicate that four of these hurricanes (1635, 1638, 1815, and 1938) and hurricane Carol, a strong category 2 storm in 1954, produced significant storm surges (>3 m) in southern Rhode Island. Storm surges of this magnitude can overtop barrier islands, removing sediments from the beach and nearshore environment and depositing overwash fans across back-barrier marshes, lakes, and lagoons. In a regime of rising sea level, accumulation of marsh, lake, or lagoon sediments on top of overwash deposits will preserve a record of overwash deposition. We examined the record of overwash deposition at Succotash salt marsh in East Matunuck, Rhode Island, and tested the correlation with historical records of intense storms. Aerial photographs taken after hurricanes in 1954 and 1938 show overwash fans deposited at the site. Analysis of 14 sediment cores from the back-barrier marsh confirmed the presence of these fans and revealed that 4 additional large-scale overwash fans were deposited within the marsh sediments. The four overwash fans deposited since the early seventeenth century at Succotash Marsh matches the historical record of significant hurricane-induced storm surge. These fans were most likely deposited by hurricanes in 1954, 1938, 1815, and either 1638 or 1635. Radiocarbon dating of two prehistoric overwash fans indicated that these were deposited between A.D. 1295– 1407 and 1404–1446 and probably represent intense hurricane strikes. In the past 700 yr, at least 7 intense hurricanes struck the southern Rhode Island coast and produced a storm surge that overtopped the barrier at Succotash Marsh.

Sedimentary evidence of intense hurricane strikes from New Jersey

Research Article| July 01, 2001 Sedimentary evidence of intense hurricane strikes from New Jersey Jeffrey P. Donnelly; Jeffrey P. Donnelly 1Department of Geological Sciences, Brown University, Providence, Rhode Island 02912, USA Search for other works by this author on: GSW Google Scholar Stuart Roll; Stuart Roll 1Department of Geological Sciences, Brown University, Providence, Rhode Island 02912, USA Search for other works by this author on: GSW Google Scholar Micah Wengren; Micah Wengren 1Department of Geological Sciences, Brown University, Providence, Rhode Island 02912, USA Search for other works by this author on: GSW Google Scholar Jessica Butler; Jessica Butler 1Department of Geological Sciences, Brown University, Providence, Rhode Island 02912, USA Search for other works by this author on: GSW Google Scholar Richard Lederer; Richard Lederer 1Department of Geological Sciences, Brown University, Providence, Rhode Island 02912, USA Search for other works by this author on: GSW Google Scholar Thompson Webb, III Thompson Webb, III 1Department of Geological Sciences, Brown University, Providence, Rhode Island 02912, USA Search for other works by this author on: GSW Google Scholar Geology (2001) 29 (7): 615–618. https://doi.org/10.1130/0091-7613(2001)029<0615:SEOIHS>2.0.CO;2 Article history received: 02 Nov 2000 rev-recd: 05 Mar 2001 accepted: 15 Mar 2001 first online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share MailTo Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation Jeffrey P. Donnelly, Stuart Roll, Micah Wengren, Jessica Butler, Richard Lederer, Thompson Webb; Sedimentary evidence of intense hurricane strikes from New Jersey. Geology 2001;; 29 (7): 615–618. doi: https://doi.org/10.1130/0091-7613(2001)029<0615:SEOIHS>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Nine Vibracores from the backbarrier marsh at Whale Beach, New Jersey, reveal three large-scale overwash deposits associated with historic and prehistoric storms. The uppermost and smallest overwash fan was deposited in the Ash Wednesday northeaster of March 5–8, 1962. A second more substantial overwash fan between 100 and 35 cm depth dates to the late eighteenth or early nineteenth century. This fan was most likely deposited during the 1821 hurricane, the only intense hurricane to make landfall in New Jersey in the past 350 yr. A third, larger overwash fan between 200 and 300 cm depth was deposited between A.D. 1278 and 1438 and is likely the result of a prehistoric intense hurricane strike. The combination of historical and stratigraphic evidence indicates that two intense hurricanes (winds >50 m s−1) have likely made landfall on the southern New Jersey coast in the past 700 yr, resulting in an annual landfall probability of 0.3%. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Aspects of Hatching Success and Chick Survival in Gull-Billed Terns in Coastal Virginia

-Because of a long-term population decline in Gull-billed Terns (Sterna nilotica) nesting along the coast of Virginia, we began a three-year study in 1994 to monitor hatching success and survival of Gull-billed Tern chicks at several Virginia colony sites. Colonies were located on either small, storm-deposited shellpiles along marsh fringes or large, sand-shell overwash fans of barrier islands. Nests were monitored one to three times a week for hatching success, and enclosures were installed around selected nests to monitor chick survival from hatching to about two weeks of age. Hatching success was lower in marsh colonies than island colonies, and was lower in 1995 than in 1994 and 1996, primarily because of flooding. The average brood size of nests where at least one chick hatched was 1.99 chicks. Survival rates of chicks to 14 days depended on hatch order and year but not brood size (one vs. two or more) or time of season. First-hatched chicks had higher survival rates than second-hatched and third-hatched chicks (0.661 compared to 0.442 and 0.357, respectively). The year effect was significant only for firsthatched chicks, with lower survival in 1994 (0.50) than in 1995 (0.765) or 1996 (0.758). Overall, productivity was low (0.53 chick per nest) compared to estimates for colonies in Denmark and was attributable to nest flooding by spring and storm-driven high tides and chick predation, mostly by Great Horned Owls (Bubo virginianus). Received 8 December 1997, resubmitted 25 October 1998, accepted 16 November 1998.