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Sample records for beach ridges foredunes

  1. Meso-scale aeolian transport of beach sediment via dune blowout pathways within a linear foredune

    NASA Astrophysics Data System (ADS)

    O'Keeffe, Nicholas; Delgado-Fernandez, Irene; Jackson, Derek; Aplin, Paul; Marston, Christopher

    2016-04-01

    The evolution of coastal foredunes is largely controlled by sediment exchanges between the geomorphic sub-units of the nearshore, beach, foredune and dune field. Although blowouts are widely recognised as efficient sediment transport pathways, both event-scale and meso-scale quantification of their utility in transferring beach sediments landwards is limited. Foredunes characterised by multiple blowouts may be more susceptible to coastline retreat through the enhanced landwards transport of beach or foredune sediments. To date, a key constraint for investigations of such scenarios has been the absence of accurate blowout sediment transport records. Here we use the Sefton coast in north-west England as a study area where an unprecedented temporal coverage of LIDAR data is available between 1999 and 2015. Additionally, an extensive set of aerial photography also exists, dating back to 1945 allowing comparison of blowout frequency and magnitude together with the alongshore limits of coastline retreat. Digital terrain models are derived for each year that LIDAR data is available. Informed by LIDAR based topography and areas of bare sand (aerial photos) terrain models have been created containing individual blowouts. Differentials in 'z' values between each terrain model of each available year has identified topographic change and total levels of transport. Preliminary results have confirmed the importance of blowouts in transporting beach or foredune sediment landwards and thus potentially promoting coastline retreat. Repetition of processes across a larger number of blowout topographies will allow better identification of individual blowouts for 'event' scale field investigations to examine spatial and temporal variability of beach sediment transport via blowouts routes.

  2. Coastal foredune displacement and recovery, Barrett Beach-Talisman, Fire Island, New York, USA

    USGS Publications Warehouse

    Psuty, N.P.; Pace, J.P.; Allen, J.R.

    2005-01-01

    Coastal foredune mobility has been tracked at Fire Island National Seashore since 1976 with annual field surveys and analysis of frequent aerial photography. Sequential mapping of the foredune crestline depicts nearly islandwide displacement during major storm events, such as in 1992, and localized displacement during alongshore passage of inshore circulation cells during other years. An instance of localized landward erosion and curvilinear displacement along approximately 400 m of foredune occurred in 1994, followed by recovery over the next nine years. Data from annual surveys and partially supported by four LIDAR flights establish that volume recovery rates in the foredune ranged from about 1.0 m3/m/yr to nearly 12.0 m3/m/yr. Analysis of the foredune morphology and location shows nearly complete recovery of foredune shape and dimension during this interval and it also demonstrates that there has been inland displacement of the foredune crestline of up to 40 m. Total volume recovery within the localized foredune erosion site was greatest, between 34 m3/m to 47 m3/m, in areas of greatest displacement and eventually contributed to creation of a foredune of similar dimension along the entire eroded zone. This process of erosion and recovery describes a mechanism for foredune dimension retention during episodic erosion and displacement and may be a model for foredune persistence accompanying barrier island migration.

  3. Coastal foredune displacement and recovery, Barrett Beach-Talisman, Fire Island, New York, USA

    USGS Publications Warehouse

    Psuty, N.P.; Pace, J.P.; Allen, J.R.

    2005-01-01

    Coastal foredune mobility has been tracked at Fire Island National Seashore since 1976 with annual field surveys and analysis of frequent aerial photography. Sequential mapping of the foredune crestline depicts nearly islandwide displacement during major storm events, such as in 1992, and localized displacement during alongshore passage of inshore circulation cells during other years. An instance of localized landward erosion and curvilinear displacement along approximately 400 m of foredune occurred in 1994, followed by recovery over the next nine years. Data from annual surveys and partially supported by four LIDAR flights establish that volume recovery rates in the foredune ranged from about 1.0 m3/m/yr to nearly 12.0 m 3/m/yr. Analysis of the foredune morphology and location shows nearly complete recovery of foredune shape and dimension during this interval and it also demonstrates that there has been inland displacement of the foredune crestline of up to 40 m. Total volume recovery within the localized foredune erosion site was greatest, between 34 m3/m to 47 m3/m, in areas of greatest displacement and eventually contributed to creation of a foredune of similar dimension along the entire eroded zone. This process of erosion and recovery describes a mechanism for foredune dimension retention during episodic erosion and displacement and may be a model for foredune persistence accompanying barrier island migration. ?? 2005 Gebru??der Borntraeger.

  4. Evolution of a foredune and backshore river complex on a high-energy, drift-aligned beach

    NASA Astrophysics Data System (ADS)

    Heathfield, Derek K.; Walker, Ian J.

    2015-11-01

    This paper examines the multi-decadal evolution of a foredune and backshore river complex on a wave-dominated, drift-aligned coast at Wickaninnish Bay on southwestern Vancouver Island, British Columbia, Canada. Local shoreline positions are generally prograding seaward as fast as + 1.46 m a- 1 in response to rapid regional tectonic uplift and positive onshore sediment budgets. The northern end of the foredune system has extended rapidly alongshore in response to net northward littoral drift. Despite these net accretional responses, the beach-dune system experiences relatively frequent (return interval ~ 1.53 years) erosive events when total water levels exceed a local erosional threshold elevation of 5.5 m above regional chart datum. Geomorphic recovery of the beach-dune system from erosive events is usually rapid (i.e., within a year) by way of high onshore sand transport and aeolian delivery to the upper beach. This response is complicated locally, however, by the influence of a backshore river that alters spatial-temporal patterns of both intertidal and supratidal erosion and deposition. Historic landscape changes and rates of shoreline positional change are derived from several years of aerial photography (1973, 1996, 2007, 2009, 2012) using the USGS Digital Shoreline Analysis System (DSAS). Significant volumetric changes are also estimated from aerial LiDAR-derived DEMs in 2005, 2009 and 2012, and related morphodynamics are interpreted using a statistically constrained geomorphic change detection method. Results suggest that supratidal bar development, overwash deposition and aeolian deposition on a low-lying supratidal platform, combined with alongshore extension of the foredune complex, is forcing Sandhill Creek to migrate northward in the direction of beach drift. In response, the river actively erodes (- 1.24 m a- 1) a bluff system landward of the channel, which generates substantial sediment volumes (- 0.137 m3 m- 2 a- 1) that feed a large intertidal

  5. Beach morphodynamics and types of foredune erosion generated by storms along the Emilia-Romagna coastline, Italy

    NASA Astrophysics Data System (ADS)

    Armaroli, Clara; Grottoli, Edoardo; Harley, Mitchell D.; Ciavola, Paolo

    2013-10-01

    The objectives of this study are to examine the response of a dune and beach system on the Adriatic coastline in northern Italy to the arrival of storms, compare it with seasonal (months) and medium-term (3-year) morphodynamic change, and evaluate results predicted by the numerical model XBeach. The studied coastline stretches 4 km from the Bevano River mouth to the north of the site to the township of Lido di Classe to the south, where the beach is protected by coastal structures. Fieldwork consisted of topographic profile surveys using RTK-DGPS technology (7 times over an approx. 3-year period). 103 samples of surface sediment were collected along 20 of the cross-shore profiles at 6 distinct cross-shore positions, selected on the basis of morphological beach characteristics. Data analyses of dune and beach slopes enabled the study area to be divided into 6 separate morphological zones using the spatial (longshore and cross-shore) variation of morphologies located on the backshore and intertidal beach observed in a preliminary survey of the area. Other criteria were a spatial consistency in beach slopes and/or presence/absence of intertidal morphologies identified in the aerial photographs and Lidar data. The swash zone slope did not show any significant variability for the entire area. A weak seasonal trend in the variability of the mean foredune slope was observed, with steeper slopes typically during winter and flatter slopes during summer. Analysis of grain size revealed that the beach sediment is well-sorted fine sand tending to medium, with a decreasing trend in size from the Bevano River mouth southwards towards Lido di Classe. According to the Masselink and Short (1993) classification, the natural part of the study site has an Intermediate Barred Beach (IBB) and following the Short (1999) classification, results in a modally LBT (longshore bar-trough) or LTT (low tide terrace) with a small section being TBR (transverse bar and rip). Storms are considered

  6. Earthquakes and beach ridges on Kamchatka

    NASA Astrophysics Data System (ADS)

    Bourgeois, J.; Ortuno, M.; Thibault, C.; Higman, B.; Pinegina, T.

    2003-04-01

    There are several proposed origins for beach ridges, or berms, with the majority of studies focused on Atlantic-type margins. Primary factors invoked for beach-ridge formation include changes in sea-level, in wave climate, and in sediment supply. On subduction-zone margins, co-seismic deformation can force any of these three factors. For example, subsidence of the shoreline (local sea level rise) will generally lead to coastal erosion, whereas shoreline uplift (subduing local wave climate) will strand beach ridges. Earthquake-triggered landslides may significantly increase sediment supply. Some authors working on Pacific margins have correlated either beach ridges (e.g., A. Kurbatov on Kamchatka; P. Saltonstall and G. Carver on Kodiak), or buried erosional scarps (e.g. R.A. Meyers et al., Washington State) with subduction-zone earthquakes and the seismic cycle. Our work on Kamchatka provides examples where buried scarps and beach ridges are superimposed, each pair of which we interpret to be the result of a single seismic cycle, apparently consistent with some other data and interpretations (Kodiak, particularly). That is, in a setting where the shoreline subsides during an earthquake and recovers thereafter, beach ridges overlie buried scarps. In one case on Kamchatka, in southern Vestnik Bay, there is a spectacular outcrop illustrating this relationship. This model by no means explains all beach ridges, so identifying earthquake-forced beach ridges remains a challenge.

  7. Coastal foredune evolution: evidence for physical control

    NASA Astrophysics Data System (ADS)

    Ruggiero, P.; Zarnetske, P. L.; Mull, J.; Hacker, S.; Seabloom, E.

    2010-12-01

    Coastal dunes in the US Pacific Northwest, comprising approximately 45% of the Oregon and Washington coasts, were historically managed to maximize coastal protection through the planting of two invasive beach grass species, European beach grass (Ammophila arenaria), and American beach grass (Ammophila breviligulata). The switch in dominance from native, Elymus mollis, to invasive dune species resulted in a complete state change in coastal dune systems. Prior to the invasion of the exotic species, native dune plants formed small hillocks or short parallel ridges depending on sand supply. In contrast, the invasive beach grasses create stable foredunes, with dune ridges reaching as much as 15 to 20 meters tall which intercept sand and decrease sand supply to the back dune. Currently pressure exists to manage some of these biogeomorphic systems for ecosystem restoration rather than solely for coastal protection. To balance these competing management objectives it has become crucial to quantify the relative importance of physical versus ecological controls on coastal dune evolution over various time and space scales. In this paper we examine the remarkable evolution of the foredunes within the Columbia River Littoral Cell (CRLC) from 1988 to 2010, a time period in which quantitative topographic surveys are bracketed by quantitative ecological surveys of grass cover dominance. Most of the region’s foredunes were severely eroded during the two extraordinary winters of 1997/1998 (a major El Niño event) and 1998/1999 (a moderate La Nina event). Subsequent to these winters the beaches and foredunes have, for the most part, experienced significant seaward progradation and vertical accretion. Across the mouth of the Columbia River significant gradients exist in both the ecological (grass species dominance and density) and physical (shoreline change rates) parameters that are thought to be first order controls on coastal dune geomorphology. These gradients allow us to test

  8. Aeolian beach ridges and their significance for climate and sea level: Concept and insight from the Levant coast (East Mediterranean)

    NASA Astrophysics Data System (ADS)

    Mauz, B.; Hijma, M. P.; Amorosi, A.; Porat, N.; Galili, E.; Bloemendal, J.

    2013-06-01

    Relict beach ridges of aeolian origin and associated soils are often used for inferring relative sea level and climate with contrasting results. Most studies link the aeolian coastal deposits to regressive phases, some to high sea-level stands, and a few to intermediate relative sea-level positions. We interpret the apparent contradictions as indicating the lack of an over-arching concept and the inconsistent usage of sea level-related terms. In this paper we present an integrated morpho-sedimentological concept for a microtidal, mid-latitudinal coast and review existing data from the Levant (East Mediterranean) coast to evaluate the concept and to eliminate nomenclatural confusion. A coastal depositional environment in a semi-arid environment consists of shallow-marine, aeolian and alluvial facies which together form an aeolian beach-ridge complex as a package of strata which respond simultaneously to sea-level change. A transgressive complex forms through reworking or overstepping of the coastal foredune and a regressive complex forms by downstepping. Under transgression the aeolian beach ridge represents the highstand deposit and its adjacent shallow marine sediment is the transgressive deposit. Under regression the complex represents the falling stage and the associated downdip surface marks the lowstand. On the Levant coast we find chronologically well-constrained, offlapping aeolian beach ridges as parts of six downstepping beach ridge complexes formed between ~ 200 ka and 10 ka. The complexes represent the falling stage systems tract (FSST) of a short-lived (5th-order) depositional sequence when the shoreline shifted from a position close to the modern coastline to the shelf or below the shelf edge. Three of these FSSTs and their up dip and down dip super bounding surface together form the 4th order (~ 100 ka) sequence of the last interglacial/glacial cycle. The absence of transgressive, highstand and lowstand systems tract is explained by the poor

  9. The Magilligan beach ridge plain (Northern Ireland, UK): A detailed sedimentary approach

    NASA Astrophysics Data System (ADS)

    Tillmann, Tanja; Surmann, Kirstin; Cooper, Andrew

    2015-04-01

    Beach ridges are a common geological feature on prograded sandy coasts . Beach ridges and their subsurface deposits record past coastal processes and are indicators of previous shoreline position, shape and sea level. This work presents preliminary results and provides new information about the late Holocene development of the Magilligan Foreland in Northern Ireland (UK). The triangular beach-ridge plain of Magilligan was formed in the early and mid-Holocene as a consequence of land and sea level change and sediment abundance. The focus of the investigations is a detailed grain size analysis of beach ridge deposits using the settling tube method. The main aim is to distinguish the beach ridge deposits from the aeolian dune sand cover and to draw conclusions about the development and sedimentary formation of the beach ridges. A semi-continuous outcrop of the upper units of the beachridge plain is preserved along the coastline. The geological descriptions in the field show significant differences between adjacent outcrops and grain size analysis was undertaken to distinguish aeolian and swash-lain sediemnts. Buried soil layers and unconformities helped to define the palaeotopography which consist of a sequence of beach ridge crests and inter-ridge depressions. The beach ridges of the subsurface are independent of the modern dune topography. There are more beach ridges than previously thought.

  10. Formation of Ephemeral Bedform Turrets in Coastal Foredunes.

    PubMed

    Jackson; Cooper

    1999-09-01

    Rare, erosional turret bedforms are described in a coastal foredune environment. These ephemeral structures are formed as a result of moist columns of sand being sculpted by aeolian action of saltating particles. Mature formation of these features appears to be facilitated by the action of an advancing foredune ridge, first preserving and then isolating the turrets for further enhanced erosion within a dune environment. It is envisaged that these structures may be preserved in dune stratigraphy. PMID:10504140

  11. RPAS Monitoring of the Morphological Evolution of Coastal Foredunes

    NASA Astrophysics Data System (ADS)

    Taddia, Yuri; Corbau, Corinne; Elena, Zambello; Russo, Valentina; Pellegrinelli, Alberto; Simeoni, Umberto

    2016-04-01

    beach (about 1.50 meter amsl), isolated embryo dunes (incipient foredunes) and foredunes develop along a cross-shore section of about 30 meters; • a "depresssive" interdune of about 10 meters; • a second field of successive well-developed dunes. The first foredunes are of small dimensions (about 0.50 m height), and are aligned to the prevailing wind directions. The second field of dunes are higher (about 1 meter height) and form a "continuous" dune ridge parallel to the shoreline. Another significant advantage of this method is the possibility to obtain information on the vegetation, which is an important factor driving the evolution of coastal dunes. Different blowouts and pathways have been also mapped. The use of the orthophoto will therefore allow to collect simultaneously physical and biological data and consequently to analyze their interaction in order to improve the management of the coastal dune systems. This study exhibits how RPAS can be successfully used in representing the spatial distribution of embryo coastal dunes and in monitoring their development.

  12. Constructing notches in foredunes: Effect on sediment dynamics in the dune hinterland

    NASA Astrophysics Data System (ADS)

    Riksen, Michel J. P. M.; Goossens, Dirk; Huiskes, Hendrik P. J.; Krol, Johan; Slim, Pieter A.

    2016-01-01

    Measurements were carried out on the island of Ameland (The Netherlands) to determine whether notches cut into foredunes stimulated the supply of fresh calcareous beach and dune sand into the white and grey dune habitats behind the dunes, increasing these habitats' biological quality. Sediment characteristics and dynamics (deposition flux and grain size properties) as well as aspects of the vegetation (occurrence, composition and cover density) were studied along six transects, three behind an intact foredune and three behind a foredune with a notch cut into it. Compared to an intact foredune, the notched foredune exhibited higher deposition and accumulation behind the dune. The extra supply of sand was small, however, and for the notches studied, limited to the zone within approximately 50-60 m of the foredune's crest. Farther away from the dune, the effect of the notches became negligible. The presence of a notch did affect the grain size composition of sediment deposited behind the foredune. For intact foredunes, the grain size composition behind the dune was similar to that on the dune itself. When a notch had been cut, the sediment was finer behind the foredune, gradually coarsening away from the dune. Sand spray (deposition of sand eroded from the dune and transported in modified saltation during heavy winds) explains these granulometric results. The effect of the notches on the vegetation in the grey dune habitat behind the foredune was small and, for the notches studied, limited to the first approximately 35 m of the grey dune area, between 30 and 65 m from the foredune's crest. The notches had a greater effect on the white dune habitat but - in the opinion of the authors - this remained disproportionately small relative to the effort required for notch excavation and maintenance.

  13. Building of tropical beach ridges, northeastern Queensland, Australia: Cyclone inundation and aeolian decoration

    NASA Astrophysics Data System (ADS)

    Tamura, Toru; Nicholas, William; Brooke, Brendan; Oliver, Thomas

    2016-04-01

    Processes associated with tropical cyclones are thought responsible for building coarse sand beach ridges along the northeastern Queensland coast, Australia. While these ridges are expected to be geological records of the past cyclone, they question the general consensus of the aeolian genesis of sandy beach ridges. To explore the ridge-forming process, we carried out the GPR survey, auger drilling, pit excavation, grain-size analysis, and OSL dating for coarse sand beach ridges at the Cowley Beach, northeastern Queensland. The Cowley Beach is a mesotidal beach characterized by a low-tide terrace and steep beach face. Ten beach ridges are recognized along the survey transect that extends 700 m inland from the shore. 37 OSL ages are younger seawards, indicating the seaward accretion of the ridge sequence over the last 2700 years. The highest ridge is +5.1 m high above AHD (Australian Height Datum). Two GPR units are bounded by a groundwater surface at c. +1.5 m AHD. The upper unit is characterized by horizontal to hummocky reflectors punctuated by seaward dipping truncation surfaces. These reflectors in places form dome-like structure that appears to be the nucleus of a beach ridge. The shape and level (+2.5 m AHD) of the dome are similar to those of the present swash berm. The lower unit shows a sequence of reflectors that dip at an angle of present beach face. The sequence is dissected by truncation surfaces, some of which are continuous to those in the upper unit. Coarse sand mainly forms beach ridge deposits below +4.0 m AHD, while a few higher ridges have an upward fining layer composed of medium sand above +4.0 m, which is finer than aeolian ripples found on the backshore during the survey. In addition, pumice gravel horizons underlie the examined ridge crests. The sequence of seaward dipping reflectors indicates that the Cowley Beach, like other many sandy beaches, has prograded during onshore sand accretion by fairweather waves and has been eroded by storms

  14. Abandoned Beach Ridges in the Mejillones Peninsula, Northern Chile: Implications for Paleoseismology of Great Subduction Earthquakes.

    NASA Astrophysics Data System (ADS)

    del Río, I. A.; Gonzalez, G.; Antinao, J. L.; McDonald, E.; González-Carrasco, J. F.; Shrivastava, M. N.

    2015-12-01

    The Mejillones Peninsula, in northern Chile, shows a well-preserved set of beach ridges parallel to the present coast. These beach ridges can be observed up to 20 km inland and at 200 m above sea level. Previous dating performed in fossils extracted from the oldest beach ridges yielded ages of 400 ka (Victor et al., 2011). However, numerical ages for younger beach ridges have not been determined, therefore a complete time record is not available. InSar data show that the Mejillones Peninsula was uplifted several centimeters during the last two subduction earthquakes (Antofagasta Mw 8.1, 1995 earthquake and the Mw 7.7, 2007 Tocopilla earthquake) occurred in the area (Loveless et al., 2010). A permanent GPS station deployed by CALTECH (http://web.gps.caltech.edu/~jeff/andes/) in this peninsula has measured a coseismic uplift during the 2007 Tocopilla earthquake. This data suggest that the beach ridges were abandoned as a consequence of coseismic uplift during great subduction earthquakes and therefore they represent the long-term record of past earthquakes. In order to prove this hypothesis we excavated five trenches across the beach ridges. Our idea is to look for stratigraphic evidence of the abandonment mechanism and to collect samples for dating the beach ridges using the method of optically stimulated luminescence (OSL). The ages will be used to estimate long-term uplift rate and temporal variation of this rate. By confronting short-term uplift rate provided by GPS data with long-term rate we hope to know what it is the amount of the coseismic slip that remain in the geological record.

  15. Heightened North Pacific Storminess during Synchronous Late Holocene Erosion of Northwest Alaska Beach Ridges

    NASA Astrophysics Data System (ADS)

    Mason, Owen K.; Jordan, James W.

    1993-07-01

    A progradational regime of falling sea level and/or high sediment input has produced extensive beach ridge plains in northwest Alaska during the last 4000 yr. Eleven Chukchi Sea beach ridge complexes, oriented at various angles to wind fetch, provide a cumulative history of longshore transport and erosion. Archaeological and geological upper limiting radiocarbon ages ( n = 59) allow correlations between depositional units on seven beach ridge complexes. Progradation started 4000 yr B.P. at nearly all complexes, as eustatic sea level stabilized. Two disconformities or truncations are found on most of the complexes, providing time-parallel storm horizons, dated at 3300-1700 and 1200-900 14C yr B.P. Between 1700 and 1200 14C yr B.P. most of the complexes prograded, indicating the predominance of less-stormy conditions. Modern synoptic patterns that produce Chukchi beach ridge erosion are linked to northerly shifts in North Pacific storm tracks. The regionwide beach ridge erosional truncations correlate with records of glacier expansion, heightened precipitation evident in tree-rings, stream flooding, and shelf deposits reworked by storm surges.

  16. Granulometry of pebble beach ridges in Fort Williams Point, Greenwich Island, Antarctic Peninsula; a possible result from Holocene climate fluctuations

    USGS Publications Warehouse

    Santana, E.; Dumont, J.F.

    2007-01-01

    We present a granulometric study of emerged pebble beach ridges in the Fort Williams Point, Greenwich Island, Antarctic Peninsula. We studied 8 beach ridges from the shore up to 13.5 m above current sea level. The beach ridges are made of volcanic material from the surrounding relief, but also include glacially transported gneiss and granodiorite pebble and cobble. Based on granulometric distribution analysis of 2100 samples from 39 locations we identified evidence of 4 sequences of 1 to 3 ridges. Most of the material seems to be reworked from a till. Pavement formation by iceberg between the sequences of beach ridges suggests periods of lower temperature. The interpretation suggests that sequences of beach ridge construction formed during warmer periods of the late Holocene. This occurs in the framework of an isostatic postglacial uplift allowing the progressive mobilization of periglaciar material.

  17. Polar gravel beach-ridge systems as archive of climate variations (South Shetland Islands / Western Antarctic Peninsula)

    NASA Astrophysics Data System (ADS)

    Lindhorst, Sebastian; Schutter, Ilona; Betzler, Christian

    2014-05-01

    The architecture of polar gravel beach-ridge systems is presented and their potential as archive of past wave-climate conditions is evaluated. Raised beaches are common on paraglacial coasts which experienced a net uplift during the Holocene as the result of postglacial isostatic rebound. Ground-penetrating radar data obtained along the coasts of Potter Peninsula (King George Island) show that beach ridges unconformably overlie seaward-dipping strata of the strand plain. Whereas strand-plain progradation is the result of swash sedimentation at the beach face under enduring calm conditions, ridge construction reflects enhanced wave action at the beach as the result of increased storminess or reduced nearshore sea ice. The number of individual ridges which are preserved from a given time interval varies along the coast depending on the morphodynamic setting: Sheltered coasts are characterized by numerous small ridges, whereas fewer but larger ridges develop on exposed beaches. The sedimentary architecture of individual beach ridges is interpreted to reflect maximum wave-runup height during the time of ridge construction. Ridges at sheltered parts of the coast exhibit either seaward-dipping beds, interpreted to result from swash deposition, or an aggradational stacking pattern being the result of wave overtopping. At exposed beaches, larger ridges develop composed of seaward- as well as landward-dipping beds. Radiocarbon data indicate that the frequency of ridge building ranges from decades in low-energy settings to more than 1500 years under high-energy conditions. In the study area, beach ridges group into four distinct levels: up to 4 m, 5.5 m, 7.5 m, and 10 m above the present day storm beach. Hence, these levels are interpreted to reflect periods of increased wave activity in the area of the South Shetland Islands at about 4.3, 3.1, 1.9, and 0.35 ka cal BP.

  18. Automated Feature Extraction of Foredune Morphology from Terrestrial Lidar Data

    NASA Astrophysics Data System (ADS)

    Spore, N.; Brodie, K. L.; Swann, C.

    2014-12-01

    Foredune morphology is often described in storm impact prediction models using the elevation of the dune crest and dune toe and compared with maximum runup elevations to categorize the storm impact and predicted responses. However, these parameters do not account for other foredune features that may make them more or less erodible, such as alongshore variations in morphology, vegetation coverage, or compaction. The goal of this work is to identify other descriptive features that can be extracted from terrestrial lidar data that may affect the rate of dune erosion under wave attack. Daily, mobile-terrestrial lidar surveys were conducted during a 6-day nor'easter (Hs = 4 m in 6 m water depth) along 20km of coastline near Duck, North Carolina which encompassed a variety of foredune forms in close proximity to each other. This abstract will focus on the tools developed for the automated extraction of the morphological features from terrestrial lidar data, while the response of the dune will be presented by Brodie and Spore as an accompanying abstract. Raw point cloud data can be dense and is often under-utilized due to time and personnel constraints required for analysis, since many algorithms are not fully automated. In our approach, the point cloud is first projected into a local coordinate system aligned with the coastline, and then bare earth points are interpolated onto a rectilinear 0.5 m grid creating a high resolution digital elevation model. The surface is analyzed by identifying features along each cross-shore transect. Surface curvature is used to identify the position of the dune toe, and then beach and berm morphology is extracted shoreward of the dune toe, and foredune morphology is extracted landward of the dune toe. Changes in, and magnitudes of, cross-shore slope, curvature, and surface roughness are used to describe the foredune face and each cross-shore transect is then classified using its pre-storm morphology for storm-response analysis.

  19. Late Quaternary Alluvial Fans and Beach Ridge Systems in Jakes Valley, Central Great Basin, USA

    NASA Astrophysics Data System (ADS)

    Garcia, A. F.; Stokes, M.; Benitez, L.

    2002-12-01

    Alluvial fan and lake beach ridge landforms provide archives of the geomorphic response to Late Quaternary climate change within the Great Basin region. This study presents the first detailed results of landform mapping and soil characterization from Jakes Valley, a high altitude (1920m) and internally drained basin, located within a previously unstudied part of White Pine County, East-Central Nevada. Mountain front alluvial fans sourced from the White Pine and Egan Ranges (west-east basin margins) are characterized by four morphostratigraphic units: Qf0 (oldest) through to Qf3 (youngest). Analysis of the soil properties of these stratigraphic units reveals two landform-soil assemblages: 1) Qf0-1, characterized by well-developed calcic soils (stages III+ to IV) and 2) Qf2-3, characterized by less well-developed calcic soils (stages I to II). Beach ridge systems formed during pluvial lake highstands are extensively developed into the mid and distal parts of alluvial fans. Integrated field and aerial photograph mapping has revealed a sequence of between 4-6 ridges with linear and / or highly curved / arcuate morphologies. Beach ridge soil properties are characterized by less well-developed calcic soils (stages I+ to II) that are similar to soils formed in Qf2 alluvial fan units. The interaction between the alluvial fan and beach ridge landforms can be utilized to explore the geomorphic response in relation to climatic amelioration during the Late Pleistocene-Holocene transition. Of particular interest is the common occurrence of the curved / arcuate beach ridges which may correspond to a period of fan progradation coincident with base-level lowering.

  20. Proxy late Holocene climatic record deduced from northwest Alaska beach ridges

    SciTech Connect

    Mason, O.K.; Jordan, J.W.

    1992-03-01

    A climatically sensitive, oscillatory pattern of progradation and erosion is revealed in late Holocene accretionary sand ridge and barrier island complexes of Seward Peninsula, northwest Alaska. Archaeological and geological radiocarbon dates constrain the chronology for the Cape Espenberg beach ridge plain and the Shishmaref barrier islands, 50 km to the southwest. Cape Espenberg, the depositional sink for the northeastward longshore transport system, contains the oldest sedimentary deposits: 3700 +/- 90 B.P. (B-23170) old grass from a paleosol in a low dune. The oldest date on the Shishmaref barrier islands is 1550 +/- 70 B.P. (B-23183) and implies that the modern barrier is a comparatively recent phenomenon. Late Holocene sedimentation along the Seward Peninsula varied between intervals of rapid progradation and erosion. Rapid progradation predominated from 4000-3300 B.P. and from 2000-1200 B.P., with the generation of low beach ridges without dunes, separated by wide swales. During erosional periods higher dunes built atop beach ridges: as between 3300-2000 B.P. and intermittently from 1000 B.P. to the present. Dune formation correlates with the Neoglacial and Little Ice Age glacial advances and increased alluviation in northern and central Alaska, while rapid progradation is contemporaneous with warmer intervals of soil and/or, peat formation atop alluvial terraces, dated to 4000-3500 and 2000-1000 B.P.

  1. Beach-ridge development and lake-level variation in southern Lake Michigan

    USGS Publications Warehouse

    Thompson, T.A.

    1992-01-01

    The most accurate source of information on lake-level fluctuations in the Great Lakes is the historical record from lake-level gauges. Although it can be semiquantitatively extended back into the late 1700's, the historical record is too short to recognize long-term patterns of lake-level behavior. To extend the historical record, information must be obtained from the Great Lakes geologic record. Such information includes the elevation and age of geomorphic features and stratigraphic sequences. One of the longest geologic records of late Holocene lake-level variation is preserved in a beach-ridge complex along the southern shore of Lake Michigan called the Toleston Beach. This strandplain contains over 150 beach ridges that arc across northwestern Indiana and fan out into northeastern Illinois. Each ridge was formed during the fall from a high lake level, and the elevation of the foreshore deposits in each ridge provides information on the upper physical limit of lake level over the past 4000 years. Three scales of quasi-periodic lake-level variation were determined by radiocarbon-dating basal peats of wetlands between the ridges and by measuring the elevation of foreshore (swash) deposits within ridges. These three scales are: (1) a short-term and small-scale fluctuation of 25 to 35 years with a range of about 0.5 to 0.6 m; (2) an intermediate-term and meso-scale fluctuation of 140 to 160 years and a range of about 0.8 to 0.9 m; and (3) a long-term and large-scale fluctuation of 500 to 600 years and a range of 1.8 to 3.7 m. The short-term and intermediate-term fluctuations are reflected in the historical record. An increase in the rate of shoreline progradation from east to west across Indiana's shoreline causes differential preservation of the lake-level fluctuations. That is, groups of four to six ridges in the western part of the strandplain that formed in response to the small-scale fluctuations combine eastward into single ridges and groups of ridges

  2. Relict progradational beach ridge complex on Cat Island in Mississippi Sound

    SciTech Connect

    Rucker, J.B.; Snowden, J.O. )

    1989-09-01

    Comparative field and aerial photographic studies of the Mississippi-Alabama Gulf Coast barrier islands reveal that Cat Island, the westernmost barrier island in the series, is unique in having a large number of prominent, forested beach ridges. The Cat island ridge complex is composed of three distinct sets of subparallel east-west-trending ridges. The ridge set on the south side of the island is younger and less well-developed than the older two sets. The beach ridge sands are characterized by an ilmenite-kyanite-staurolite heavy mineral assemblage, which indicates an eastern source, ultimately the southern Appalachian igneous-metamophric complex. This mineralogy distinguishes the barrier island complex from the nearby Mississippi River deltaic sediments, which are characterized by an amphibole-rich heavy mineral suite. There is considerable evidence that the barrier island system predates the eastward progradation of the St. Bernard lobe of the Mississippi delta complex, which began its eastward progradation about 3,000 years ago and continued until its abandonment approximately 1,500 years ago.

  3. Coastal foredune evolution: evidence for ecological control

    NASA Astrophysics Data System (ADS)

    Zarnetske, P. L.; Ruggiero, P.; Mull, J.; Hacker, S.; Seabloom, E.

    2010-12-01

    The development and modification of landscape features existing at the aquatic-terrestrial interface - estuaries, salt marshes, mangroves, lacustrine environments, rivers and streams, and coastal dunes - is one of the most striking outcomes from the interactions and feedbacks between ecology and geomorphology. These distinct biophysical features arise from interactions among sediment, vegetation, and a fluid medium (air or water). Importantly, these features provide services including habitat, resources, and protection for human and ecological systems. Across 22 years (1988-2010) and 160 kilometers of coastline, we investigate the relative contributions of physical and ecological processes in shaping coastal foredunes along the Columbia River Littoral Cell (CRLC) in the U.S. Pacific Northwest (PNW). This system is particularly well suited to investigate this interplay because it contains significant gradients of physical (e.g., shoreline change rates) and ecological (e.g., vegetation species and densities) forces. Further, the two dominant sand binding grass species (invasive Ammophila grasses) are individually associated with different foredune morphologies through space and time (A. arenaria occurs on taller foredunes while A. breviligulata occurs on shorter foredunes). Within the last 22 years, A. breviligulata has spread and replaced much of A. arenaria as the dominant vegetation on CRLC foredunes. We hypothesize that after accounting for the primary physical drivers shaping foredunes (shoreline change rate, sediment accumulation rates, and frequency/intensity of storm events including El Niño/La Niña), we will find an ecological control or an interaction among physical and ecological forces on PNW coastal foredune geomorphology. Here we test whether any residual variation in interannual- to decadal-scale coastal foredune evolution is due to the change in Ammophila species abundance and density over this time period, and determine whether grass species are

  4. Geochronologic evidence for a possible MIS-11 emergent barrier/beach-ridge in southeastern Georgia, USA

    USGS Publications Warehouse

    Markewich, H.W.; Pavich, M.J.; Schultz, A.P.; Mahan, S.A.; Aleman-Gonzalez, W. B.; Bierman, P.R.

    2013-01-01

    Predominantly clastic, off-lapping, transgressive, near-shore marine sediment packages that are morphologically expressed as subparallel NE-trending barriers, beach ridges, and associated back-barrier areas, characterize the near-surface stratigraphic section between the Savannah and the Ogeechee Rivers in Effingham County, southeastern Georgia. Each barrier/back-barrier (shoreline) complex is lower than and cut into a higher/older complex. Each barrier or shoreline complex overlies Miocene strata. No direct age data are available for these deposits. Previous researchers have disagreed on their age and provenance. Using luminescence and meteoric beryllium-10 (10Be) inventory analyses, we estimated a minimum age for the largest, westernmost, morphologically identifiable, and topographically-highest, barrier/beach-ridge (the Wicomico shoreline barrier) and constrained the age of a suite of younger barrier/beach-ridges that lie adjacent and seaward of the Wicomico shoreline barrier. At the study site, the near-shore marine/estuarine deposits underlying the Wicomico shoreline barrier are overlain by eolian sand and an intervening zone-of-mixing. Optically stimulated luminescence (OSL) data indicate ages of ≤43 ka for the eolian sand and 116 ka for the zone-of-mixing. Meteoric 10Be and pedostratigraphic data indicate minimum residence times of 33.4 ka for the eolian sand, 80.6 ka for the zone-of-mixing, and 247 ka for the paleosol. The combined OSL and 10Be age data indicate that, at this locality, the barrier/beach ridge has a minimum age of about 360 ka. This age for the Wicomico shoreline-barrier deposit is the first for any Pleistocene near-shore marine/estuarine deposit in southeast Georgia that is conclusively older than 80 ka. The 360-ka minimum age is in agreement with other geochronologic data for near-coastline deposits in Georgia and South Carolina. The geomorphic position of this barrier/beach-ridge is similar to deposits in South Carolina considered to be

  5. Geochronologic evidence for a possible MIS-11 emergent barrier/beach-ridge in southeastern Georgia, USA

    NASA Astrophysics Data System (ADS)

    Markewich, H. W.; Pavich, M. J.; Schultz, A. P.; Mahan, S. A.; Aleman-Gonzalez, W. B.; Bierman, P. R.

    2013-01-01

    Predominantly clastic, off-lapping, transgressive, near-shore marine sediment packages that are morphologically expressed as subparallel NE-trending barriers, beach ridges, and associated back-barrier areas, characterize the near-surface stratigraphic section between the Savannah and the Ogeechee Rivers in Effingham County, southeastern Georgia. Each barrier/back-barrier (shoreline) complex is lower than and cut into a higher/older complex. Each barrier or shoreline complex overlies Miocene strata. No direct age data are available for these deposits. Previous researchers have disagreed on their age and provenance. Using luminescence and meteoric beryllium-10 (10Be) inventory analyses, we estimated a minimum age for the largest, westernmost, morphologically identifiable, and topographically-highest, barrier/beach-ridge (the Wicomico shoreline barrier) and constrained the age of a suite of younger barrier/beach-ridges that lie adjacent and seaward of the Wicomico shoreline barrier. At the study site, the near-shore marine/estuarine deposits underlying the Wicomico shoreline barrier are overlain by eolian sand and an intervening zone-of-mixing. Optically stimulated luminescence (OSL) data indicate ages of ≤43 ka for the eolian sand and 116 ka for the zone-of-mixing. Meteoric 10Be and pedostratigraphic data indicate minimum residence times of 33.4 ka for the eolian sand, 80.6 ka for the zone-of-mixing, and 247 ka for the paleosol. The combined OSL and 10Be age data indicate that, at this locality, the barrier/beach ridge has a minimum age of about 360 ka. This age for the Wicomico shoreline-barrier deposit is the first for any Pleistocene near-shore marine/estuarine deposit in southeast Georgia that is conclusively older than 80 ka. The 360-ka minimum age is in agreement with other geochronologic data for near-coastline deposits in Georgia and South Carolina. The geomorphic position of this barrier/beach-ridge is similar to deposits in South Carolina considered to be

  6. Spatio-Temporal Variability in Accretion and Erosion of Coastal Foredunes in the Netherlands: Regional Climate and Local Topography

    PubMed Central

    Keijsers, Joep G. S.; Poortinga, Ate; Riksen, Michel J. P. M.; Maroulis, Jerry

    2014-01-01

    Depending on the amount of aeolian sediment input and dune erosion, dune size and morphology change over time. Since coastal foredunes play an important role in the Dutch coastal defence, it is important to have good insight in the main factors that control these changes. In this paper the temporal variations in foredune erosion and accretion were studied in relation to proxies for aeolian transport potential and storminess using yearly elevation measurements from 1965 to 2012 for six sections of the Dutch coast. Longshore differences in the relative impacts of erosion and accretion were examined in relation to local beach width. The results show that temporal variability in foredune accretion and erosion is highest in narrow beach sections. Here, dune erosion alternates with accretion, with variability displaying strong correlations with yearly values of storminess (maximum sea levels). In wider beach sections, dune erosion is less frequent, with lower temporal variability and stronger correlations with time series of transport potential. In erosion dominated years, eroded volumes decrease from narrow to wider beaches. When accretion dominates, dune-volume changes are relatively constant alongshore. Dune erosion is therefore suggested to control spatial variability in dune-volume changes. On a scale of decades, the volume of foredunes tends to increase more on wider beaches. However, where widths exceed 200 to 300 m, this trend is no longer observed. PMID:24603812

  7. Quartz thermoluminescence in a storm deposit and a welded beach ridge

    NASA Astrophysics Data System (ADS)

    Rink, W. J.; Pieper, K. D.

    2001-12-01

    We examined the natural residual thermoluminescence (NRTL) of quartz in samples collected from the surface and the subsurface of the beach on a sand spit in the Gulf of Mexico located at St. Joseph Peninsula State Park near Apalachicola Florida. The subsurface samples were collected within two berm structures that respectively, represented a hurricane deposit and a subsequently deposited smaller tidal berm (beach ridge) produced by wave action during a seven-week period following the storm. Higher NRTL was found in the underwater zone of the beach surface than in the areas exposed to full daylight on the beach and in the dunes (seawater is known to strongly absorb the ultraviolet component of daylight). In each of the berms, similar variations in NRTL could confidently be correlated to primary sedimentary structures. Strong transitions in NRTL occurred at boundaries between sedimentary units. These variations were used to interpret processes of berm formation and the identity of local sources of quartz incorporated into the berms.

  8. Internal architecture of foredunes and their dynamics resolved by GPR (Regneville inlet, Normandy, France)

    NASA Astrophysics Data System (ADS)

    Juliette, Baumann; Dujardin, Jean-Rémi; Duringer, Philippe; Robin, Nicolas; Schuster, Mathieu; Bano, Maksim

    2014-05-01

    Foredunes are the foremost dunes formed on the backshore of beaches by aeolian sand deposition trapped by vegetation. They are classical large scale features that develop along a large part of sandy coasts of the world. There are many papers covering various aspects of foredune (initiation, evolution, dynamics) but their internal architecture which reflects their dynamics is still not well known. Active and relic foredunes from the Regneville inlet have been surveyed with Ground Penetrating Radar (GPR). GPR is a non-invasive geophysical method based on high frequency electromagnetic wave propagation which can provide very detailed and continuous images of the subsurface. One of the goals of GPR measurements is to determine the geometries of fine structures by imaging the structures of sedimentary deposits. The GPR profiles have been obtained by using the 100, 250, 500 and 800 MHz shielded antenna and the acquisition mode was a constant offset. Direct field observations (natural outcrops and trenches) along modern foredunes during different hydrodynamic conditions complete their sedimentary/architectural characterization and bring a strong control for the interpretation of the GPR profiles. GPR allowed here to identify buried erosional surfaces and depositional stratifications. A conceptual model developing their formation and evolution can then be proposed: it starts with a phase of wave erosion followed by a more complex phase of eolian sand accumulation (vertical aggradation, lateral accretion). Shore-perpendicular GPR profiles reveal that the internal architecture of foredunes is marked by several sharp and seaward concave truncations which correspond to ancient marine scarps. They are the result of the erosion by waves of a foredune during storms or high-tides. Some of these scarps can be detected from the geomorphology (steps in the topographic profile, change in vegetation type), others not because they are sealed by blown sands accumulation (smoothed

  9. Ridge-Runnel and Swash Dynamics Field Experiment on a Steep Meso-Tidal Beach

    NASA Astrophysics Data System (ADS)

    Figlus, J.; Chardon-Maldonado, P.; Puleo, J. A.

    2014-12-01

    Ridge-runnel (RR) systems are morphological features that may form in the intermittently wet and dry zone of the beach immediately after storm events. Their onshore migration provides a natural way of recovery for an eroded beach but the detailed swash interactions and complex feedback mechanisms between wave dynamics, sediment transport and profile evolution are not well understood and challenging to measure in-situ. During a storm, elevated water levels and large waves can significantly erode the beach profile in a matter of hours through offshore-directed sediment transport. The beach recovery process, on the other hand, occurs over a much longer time period during less intense wave conditions. In the beginning of this 3-week field campaign at South Bethany Beach, Delaware, a Nor'easter, eroded significant portions of this steep, meso-tidal beach and formed a pronounced RR system which then evolved during the less energetic conditions after the storm. An extensive cross-shore array of sensors was installed immediately after the storm measuring near-bed velocity profiles (5 Nortek Vectrino Profilers) and horizontal velocities (6 Sontec Electromagnetic Current Meters; 1 side-looking Nortek Vectrino) suspended sediment concentrations (10 Optical Backscatter Sensors OBS-3+), and pressure fluctuations (7 GE Druck pressure transducers) in the swash zone. Dense topography surveys of the RR system were conducted twice a day during low tide conditions with a Leica RTK GPS rover system. In addition, sediment grab samples along the entire RR cross-section were collected daily. An offshore ADCP with surface wave tracking capability (Nortek 2MHz AWAC AST) measured directional wave spectra and current profiles at a water depth of approximately 6m. The RR system showed rapid onshore migration over the two tide cycles immediately after the storm, followed by a period of vertical ridge accretion of up to 3 ft at certain locations. A first look at the collected data and analysis

  10. Beach-ridge development in Lake Michigan: Shoreline behavior in response to quasi-periodic lake-level events

    USGS Publications Warehouse

    Thompson, T.A.; Baedke, S.J.

    1996-01-01

    Strandplains of arcuate beach ridges are common in coastal embayments in parts of the Great Lakes. Similarities in beach-ridge development and geomorphology are recognizable in many of the embayments in the Lake Michigan basin despite differences in size and shape, available sediment type and supply, predepositional slope and topography, and hydrographic regime between the embayments. These similarities are primarily a product of three scales of quasiperiodic lake-level variation ranging in time from 30 to 600 years and in water level change from 0.5 to 3.7 m. The interaction of these three lake-level variations can be represented on a Curray (1964) diagram (rate of water level change versus rate of sediment supply). The position of any shoreline on the diagram and the type of behavior the shoreline is experiencing is a product of the interaction of the three variations. Two large Strandplains of late Holocene beach ridges occur at opposite ends of Lake Michigan (Toleston Beach and Thompson embayment). The two areas exhibit similar patterns of beach-ridge development for the past 2600 calendar years. That is, both areas form beach ridges about every 30 years. Groups of 4 to 6 beach ridges reflect a longer-term lake-level variation of about 150 years. Only during the largest variation of about 600 years in duration do the two areas differ. The rise to the 1700 cal yr B.P. high caused the erosion of beach ridges back to 2800 cal yrs B.P. in northern Lake Michigan. In southern Lake Michigan, no erosion occurred during this lake level high. Differences in shoreline development between the two areas are related to the rate of sediment supply to the shorelines. As the sediment sink for the southern half of Lake Michigan, the southern strandplain received a greater sediment flux than the northern strandplain during the latter part of the late Holocene and produced a continuous record of beach-ridge development. ?? 1995 Elsevier Science B.V. All rights reserved.

  11. Integrated analysis of beach ridge and lagoon systems as indicator of sea-level changes

    NASA Astrophysics Data System (ADS)

    Sander, Lasse; Hede, Mikkel U.; Fruergaard, Mikkel; Morigi, Caterina; Johannessen, Peter N.; Nielsen, Lars; Clemmensen, Lars B.; Nielsen, Lars H.; Pejrup, Morten

    2015-04-01

    Beach ridges and lagoons are common features of the modern coastal landscape in much of Denmark and represent an important part of the Holocene raised marine deposits. We here present our results from investigations into the possibilities of retrieving continuous relative sea-level (RSL) information from these sedimentary archives, as facilitated by the analysis of surface morphology, coring, subsurface imaging, absolute chronology, and modern analogues. The island of Samsø (55˚51'N, 10˚36'E) was chosen as a case study example. While each of the used archives merely covers a part of the mid to late Holocene developments, their joint analysis allows identifying and separating periods of rapid RSL rise, stability and fall over most of the island's marine stage. We present possible correlations of the data from the lagoons with data from a wide beach-ridge system and suggest causal relations of the RSL reconstruction with the spatial arrangements of marine and glacial landforms on Samsø. The integrated use of a geographical perspective combined with geological precision and methodology has proven to be of great value for understanding temporal, spatial, and process relations in the investigated coastal environment. The study stresses the value of analyzing genetically independent though complementary sedimentary archives to retrieve more complete and potentially more robust results. The presented approach may be useful in microtidal, sediment-surplus environments with a transgressive-regressive Holocene RSL history.

  12. Anthropogenic disruption to the seismic driving of beach ridge formation: The Sendai coast, Japan.

    PubMed

    Goff, James; Knight, Jasper; Sugawara, Daisuke; Terry, James P

    2016-02-15

    The expected geomorphic after-effects of the Mw 9.0 Tōhoku-oki earthquake of 11 March 2011 (eastern Japan) are summarized by a schematic model of seismic driving, which details seismogenic disturbances to sediment systems that affect the rate or timing of sediment delivery to coastlines over timescales of 10(2)-10(4)years. The immediate physical environmental responses to this high-magnitude earthquake included a large tsunami and extensive region-wide slope failures. Normally, slope failures within mountain catchments would have significant impacts on Japan's river and coastal geomorphology in the coming decades with, for example, a new beach ridge expected to form within 20-100 years on the Sendai Plain. However, human activity has significantly modified the rate and timing of geomorphic processes of the region, which will have impacts on likely geomorphic responses to seismic driving. For example, the rivers draining into Sendai Bay have been dammed, providing sediment traps that will efficiently capture bedload and much suspended sediment in transit through the river system. Instead of the expected ~1 km of coastal progradation and formation of a ~3m high beach ridge prior to the next large tsunami, it is likely that progradation of the Sendai Plain will continue to slow or even cease as a result of damming of river systems and capture of river sediments behind dams. The resulting reduction of fluvial sediment delivery to the coast due to modification of rivers inadvertently makes seawalls and other engineered coastal structures even more necessary than they would be otherwise. PMID:26657245

  13. Regularity and predictability of Holocene beach-ridge building and erosion

    SciTech Connect

    Fairbridge, R.W.

    1985-01-01

    The history of the behavior of the world sea level during the Holocene Epoch, independent of glacioisostatic, hydroisostatic, neotectonic and compactional processes, is of considerable contemporary interest: both from scientific and humanitarian (political) points of view. If a rapid rise is imminent, plans and preparations are in order. If a long-term record of fluctuating sea level is demonstrable, ways must be discovered to discriminate between natural and anthropogenically activated components in modern tide-gauge data. In sites of abundant sand and gravel supply, beach ridges have been building prograded coastal plains for the last 6000 year or more. These exceptional landforms are found from high latitudes (Alaska, Baffin Island, Hudson Bay), to the subtropics (Mexico, Western Australia) and to the equatorial belt (Brazil, West Africa, Bay of Bengal, Java Sea). The ridges number up to 100 or more, displaying remarkable uniformity in elevation and separation, to suggest regular hydrodynamic cyclicity triggered by variable storminess and wave incidence, current gyre velocity, eustatic change of MSL, and geoidal effect due to changing spin rate of the globe. Radiocarbon dating suggests cycles related to both lunar tidal periods (18.6, 558 yr) and solar radiation/planetary periods (11, 22, 45, 90, 180, 360 yr). Interdisciplinary studies should facilitate predictability. Recent spectral analyses of sea level and climate proxies demonstrate critical phase relationships, especially with respect to the lunar 18.6 year and solar 11/22 year periodicities.

  14. Effect of a Shore-Oblique Ridge on Beach and Bar Morphodynamics at Kennedy Space Center, Cape Canaveral, Florida

    NASA Astrophysics Data System (ADS)

    Kline, S. W.; Adams, P. N.; Plant, N. G.; MacKenzie, R. A.; Jaeger, J. M.

    2012-12-01

    Processes linking beach and bar response to external wave forcing are poorly understood where spatial complexities, such as inner shelf shoals, are present. At NASA Kennedy Space Center (KSC), Cape Canaveral, Florida, two persistant surfzone sand bars occur in a region that also includes cape-associated shoals and multiple shore-oblique ridges at depths below the fair-weather wave base of sediment transport. These features transform incoming deep-water waves, redistributing the spatial pattern of wave energy along- and cross-shore. To observe beach and sandbar response in this complex environment we have collected and georectified hourly beach images at KSC since April 2010. Comparisons of imagery to monthly differential GPS surveys reveal that a double-bar system, with ~25-50 m spacing between crests, has persisted over the last 2 years. Welding of the inner and outer bars occurs intermittently. The preferred welding location coincides with a dune overwash area that has been an erosion hotspot (EHS) over the last decade. Strong nor'easter activity in November 2011 activated wave breaking across a large (~10 km long, ~500 m wide, ~5 m tall) shore-oblique subaqueous ridge that intersects the nearshore system at the EHS. Our observations allow testing of a hypothesis that the ridge controls nearshore morphodynamics through two mechanisms: 1) by focusing, dissipating, and shadowing wave energy, especially during storm events and 2) by providing a sediment source to the nearshore system. The former mechanism is supported through image and survey analysis that shows beach and bar behavior differ updrift and downdrift of the ridge-beach intersection. Three ADCPs were deployed during the early 2010-2011 and late 2011-2012 winter nor'easter seasons to measure wave transformation and current structures in this region. During the most recent deployment, an instrument on the ridge's leeward side was nearly completely buried, yet measured bottom currents (< 50 cm/s) do not

  15. Evolution of foredune barriers at Admiral Bay, Western Australia - Implications for Holocene relative sea levels and extreme wave events

    NASA Astrophysics Data System (ADS)

    Engel, Max; May, Simon Matthias; Scheffers, Anja; Squire, Peter; Pint, Anna; Kelletat, Dieter; Brückner, Helmut

    2014-05-01

    Only few geomorphological studies on the Canning Coast of Western Australia exist to date, most probably reflecting its remoteness and low population density. However, WA's annual gross state product (GSP) growth of ~5 % during the past decade and the highest GSP per capita nationwide resulting from a mining boom increase public attention as well as the demand for precise information on landscape inventory and evolution. In this paper, new data from a sequence of vegetated foredune barriers, gradually being eroded by a migrating estuary inside the macrotidal Admiral Bay (also known as McKelson Creek, Whistle Creek or Panganunganyjal), 110 km southwest of Broome, are presented. Based on sediment cores, DGPS-based elevation transects, and stratigraphical analyses on outcrops of the relict foredunes, we aim at (i) reconstructing lateral coastal changes during the Holocene, (ii) drawing inferences on relative sea-level (RSL) change, and (iii) identifying and dating imprints of extreme-wave events. Sedimentary analyses comprise documentation of bedding structures, foraminiferal content and macrofaunal remains (including shell taphonomy), grain size, and organic matter. Chronological contexts are established using 26 14C-AMS datings. Marine flooding of the pre-Holocene base landward of the 2.5 km-wide foredunes can be pinpointed to 7400-7200 cal BP. A mangrove ecosystem established and was quickly replaced by intertidal coarse sands after only 200-400 years. The high-energy intertidal environment prevailed until c. 4000 cal BP before turning into the present supralittoral mudflat environment. At that time, coastal regression led to beach progradation and isochronic formation of foredune barriers. Drivers of progradation were a stable RSL or gradual RSL fall after the mid-Holocene highstand and a positive sand budget provided by high sublittoral productivity of calcareous shells in combination with erosion at the adjacent sandstone capes and longshore drift. The foredunes

  16. Ground-penetrating radar study of beach-ridge deposits in Huangqihai Lake, North China: the imprint of washover processes

    NASA Astrophysics Data System (ADS)

    Shan, Xin; Yu, Xinghe; Clift, Peter D.; Tan, Chengpeng; Li, Shunli; Wang, Zhixing; Su, Dongxu

    2016-03-01

    Determining the origin of beach ridges in lacustrine basins can often be problematic. The sedimentary processes responsible for formation of beach ridges on the north shore of Huangqihai Lake were investigated by using ground penetrating radar (GPR). A 400 MHz GPR antenna was used to achieve a high vertical resolution of 0.04-0.08 m. The radar stratigraphy was then determined using principles of seismic stratigraphy. The radar facies (RF) were determined by analyzing internal configuration and continuity of reflections, as well as reflection termination patterns. The identified RF fall into three groups (inclined, horizontal and irregular). The inclined group consists of RF that display inclined reflections. The horizontal group consists of RF that exhibit predominantly horizontal reflections. In the irregular group, the reflections are typically weak. RF with reflections with gently landward dips in the shore-normal profile are interpreted as washover sheet deposits. RF with steeply landward-dipping and imbricated reflections are interpreted as washover lobes. Washover sheets develop when overwash fails to enter a significant body of water and sedimentation takes place entirely on the relatively flattened topography. Washover lobe development occurs when overwash enters a region in which topography dips steeply landward, and sedimentation takes place on the surface of washover sheets or previous washover lobes. The beach-ridge deposits are interpreted as being formed entirely from vertically and laterally stacked washover sheets and washover lobes. They were formed by wave-dominated processes and secondary overwash processes supplemented by longshore currents.

  17. AMS-dated mollusks in beach ridges and berms document Holocene sea-level and coastal changes in northeastern Kuwait Bay

    NASA Astrophysics Data System (ADS)

    Reinink-Smith, Linda M.

    2015-09-01

    In northeastern Kuwait, ancient beach ridges and associated berms are separated from the present shoreline by a 4-6 km-wide sabkha. A diverse mollusk fauna in the beach ridges attests to a former open marine environment. A total of 21 AMS dates were obtained in this study. Thirteen mollusk samples from beach ridges yielded AMS dates ranging from ~ 6990 cal yr BP in the southeast to ~ 3370 cal yr BP in the northwest, suggesting a southeast to northwest age progression during the Holocene transgression. In contrast, four samples from berms throughout the study area yielded AMS dates of 5195-3350 cal yr BP showing no age progression; these berms consist largely of Conomurex persicus gastropods that aggregated by storms during a highstand at ~ 5000-3500 cal yr BP. The berms are presently at ~ + 6 m above sea level, 2-3 m above the beach ridges. Human settlements were common on the ridge crests before and after the highstand. Regression to present-day sea level commenced after the highstand, which is when the sabkha began forming. A landward, marine-built terrace, which yielded AMS dates > 43,500 14C yr BP, probably formed during Marine Oxygen Isotope Stage 5e and hence is not genetically related to the beach ridges.

  18. Polar gravel beach-ridge systems: Sedimentary architecture, genesis, and implications for climate reconstructions (South Shetland Islands/Western Antarctic Peninsula)

    NASA Astrophysics Data System (ADS)

    Lindhorst, Sebastian; Schutter, Ilona

    2014-09-01

    The sedimentary architecture of polar gravel-beach ridges is presented and it is shown that ridge internal geometries reflect past wave-climate conditions. Ground-penetrating radar (GPR) data obtained along the coasts of Potter Peninsula (King George Island) show that beach ridges unconformably overlie the prograding strand plain. Development of individual ridges is seen to result from multiple storms in periods of increased storm-wave impact on the coast. Strand-plain progradation, by contrast, is the result of swash sedimentation at the beach-face under persistent calm conditions. The sedimentary architecture of beach ridges in sheltered parts of the coast is characterized by seaward-dipping prograding beds, being the result of swash deposition under stormy conditions, or aggrading beds formed by wave overtopping. By contrast, ridges exposed to high-energy waves are composed of seaward- as well as landward-dipping strata, bundled by numerous erosional unconformities. These erosional unconformities are the result of sediment starvation or partial reworking of ridge material during exceptional strong storms. The number of individual ridges which are preserved from a given time interval varies along the coast depending on the morphodynamic setting: sheltered coasts are characterized by numerous small ridges, whereas fewer but larger ridges develop on exposed beaches. The frequency of ridge building ranges from decades in the low-energy settings up to 1600 years under high-energy conditions. Beach ridges in the study area cluster at 9.5, 7.5, 5.5, and below 3.5 m above the present-day storm beach. Based on radiocarbon data, this is interpreted to reflect distinct periods of increased storminess and/or shortened annual sea-ice coverage in the area of the South Shetland Islands for the times around 4.3, c. 3.1, 1.9 ka cal BP, and after 0.65 ka cal BP. Ages further indicate that even ridges at higher elevations can be subject to later reactivation and reworking. A

  19. Recent coastal evolution in a carbonate sandy environments and relation to beach ridge formation: the case of Anegada, British Virgin Islands

    NASA Astrophysics Data System (ADS)

    Cescon, Anna Lisa; Cooper, J. Andrew G.; Jackson, Derek W. T.

    2014-05-01

    In a changing climate context coastal areas will be affected by more frequent extreme events. Understanding the relationship between extreme events and coastal geomorphic response is critical to future adaptation plans. Beach ridge landforms commonly identified as hurricane deposits along tropical coasts in Australia and in the Caribbean Sea. However their formative processes in such environments are still not well understood. In particular, the role of different extreme wave events (storm waves, tsunami waves and extreme swell), in generating beach ridges is critical to their use as palaeotempestology archives. Anegada Island is a carbonate platform situated in the British Virgin Island between the Atlantic Ocean and the Caribbean Sea. Pleistocene in age, Anegada is surrounded by the Horseshoe fringing coral reef. Two Holocene sandy beach ridge plains are present on the western part of the island. The north beach ridge plain is Atlantic facing and has at least 30 ridges; the south beach ridge plain is Caribbean Sea facing and contains 10 ridges. Historical aerial photos enabled the shoreline evolution from 1953 to 2012 to be studied. Three different coastal domains are associate with the beach ridge plains: strong east-west longshore transport affects the north coastline, the south-west coastline from West End to Pomato Point represents an export corridor for these sediments and finally, along the southern coastline, from Pomato Point to Settling Point the area presents a depositional zone with little to no change in the last 70 years. The link between the extreme wave events that have affected Anegada Island in the last 70 years and beach ridge creation is discussed. Hurricane Donna crossed over Anegada Island in 1960: its geomorphological signature is tracked in the shoreline change analysis and its implication in beach ridge formation is discussed. Anegada Island has also been impacted by tsunami waves (Atwater et al., 2012) and a comparative discussion of the

  20. Contextualization of Holocene beach ridge systems for relative sea-level reconstruction using the SRTM elevation model

    NASA Astrophysics Data System (ADS)

    Sander, Lasse; Raniolo, Luís Ariel; Alberdi, Ernesto; Pejrup, Morten

    2014-05-01

    Beach ridge plains are a common feature of prograding coastlines and they have in the past been widely used as geomorphological archives for the reconstruction of past coastal dynamics, event chronologies or late quaternary sea-level change. The most critical parameters for sea-level related research are the consistent definition and confidence of information on surface elevation of the beach ridge deposits. In most parts of the world, the availability of high-resolution geodata is very limited. The measurement of e.g. high-precision GPS (Global Positioning System) data is costly, time-consuming and essentially of limited spatial coverage. The SRTM (Shuttle Radar Topography Mission) dataset is a freely-available digital surface model covering landmasses between approximately 60° N and 56° S at a 90 m (3 arc seconds) resolution. The model elevations are indicated without decimals (integer) and are projected for the WGS84 ellipsoid. On a beach ridge plain at Caleta de los Loros, Río Negro, Argentina, we observed a good correlation of GPS-RTK (GPS-Real Time Kinematic) measurements (estimated vertical accuracy: <0,1 m) with the SRTM elevation model along a cross-ridge transect. An average vertical deviation of 0,96 m (SD: 0,48m) between the SRTM and the GPS-RTK-based elevations was determined for mostof the beach ridge transect (79% of length). Larger errors (maximum average error: 2,78 m, SD: 1,88 m) can be explained by eolian deposition and dune migration during the approx. 13 years between the date of SRTM data acquisition and our GPS measurement. This interpretation is supported by a multi-decadal sequence of Landsat false-color composites. Vegetation cover and rounding errors are further possible factors in explaining vertical deviation. The consistency of data quality was confirmed by a comparison study using a LiDAR (Light detection and ranging)-based digital elevation model (vertical accuracy: <0,1 m) to extract surface elevations on an extensive beach ridge

  1. Development of the barrier system at Ferry Beach, Maine--Evidence of transgressive and regressive phases

    SciTech Connect

    Van Heteren, S.; Fitzgerald, D.M. . Dept. of Geology); Fink, L.K. Jr. . Dept. of Geological Sciences)

    1993-03-01

    Ferry Beach is part of a barrier system that borders the southern end of the Saco Embayment. This portion of the coast is characterized by mesotidal conditions and low wave energy. The beaches in this area are fronted by a low gradient sandy offshore and backed by a continuous foredune ridge. The backbarrier consists of fresh water ponds at Ferry Beach, in the central part, and salt marshes adjacent to Saco River and Goosefare Brook. New ground-penetrating radar and vibracore data, supplemented with topographic profiles, have enabled the delineation and interpretation of the major stratigraphic units present at Ferry Beach. The internal structure of the barrier lithosome and backbarrier sedimentary unit shows evidence of three phases in the late Holocene development of the study area. The first, transgressive phase is identified in the unconformity between glaciomarine clays of the Presumpscot Formation and overlying backbarrier, barrier, and shoreface units. The second, transitional phase is recognized as a distinctly outlined sandy unit with landward and southward dipping layers on top of backbarrier and shoreface deposits. The unit is inferred to be either a recurved spit deposit or part of a new barrier incompletely welded to the older beach ridges. The third, regressive phase has resulted in the present-day beach ridge system. The barrier lithosome associated with this phase is characterized by 150 m of offshore dipping layers. The evolutionary style of the Ferry Beach barrier system is likely linked to variations in rates of relative sea-level rise and sediment supply. Rapid rise of relative sea level was the determining factor during Phase 1, while offshore and longshore (notably from the Saco River) sediment supply during the Holocene sediment maximum caused the barrier expansion during Phases 2 and 3.

  2. Probabilistic assessment of beach and dune changes

    USGS Publications Warehouse

    Sallenger, A.H., Jr.; Stockdon, H.; Haines, J.; Krabill, W.; Swift, R.; Brock, J.

    2004-01-01

    The recent availability of spatially-dense airborne lidar data makes assessment of the vulnerability of beaches and dunes to storm impacts practical over long reaches of coast. As an initial test, elevations of the tops (D high) and bases (Dlow) of foredune ridges along a 55-km reach on the northern Outer Banks, NC were found to have considerable spatial variability suggesting that different parts of the barrier island would respond differently to storms. Comparing statistics of storm wave runup to D high and Dlow, we found that net erosion due to overwash and dune retreat should be greatest at the northern and southern ends of the study area and least in the central section. This predicted spatial pattern of storm-induced erosion is similar to the spatial pattern of long-term erosion of the shoreline which may be controlled by additional processes (such as gradients in longshore transport) as well as the cross-shore processes considered here. However, consider feedback where at erosional hot spots there is a deficit of sand (caused by gradients in longshore transport) which lead to lower dunes and enhanced erosional cross-shore processes, such as overwash. Hence, the erosional hot spots would be exacerbated, further increasing the vulnerability of the beach and dunes to net erosion.

  3. Late Quaternary development of the Croatan Beach Ridge Complex, Bogue Sound, Bogue Banks, NC, USA and implications for coastal evolution

    NASA Astrophysics Data System (ADS)

    Lazar, Kelly B.; Mallinson, David J.; Culver, Stephen J.

    2016-06-01

    Foraminiferal, sedimentological, geophysical, and geochronologic data were utilized to elucidate the late Quaternary geologic development of the Croatan Beach Ridge Complex (CBRC), Bogue Sound, and Bogue Banks, North Carolina, USA. The CBRC is a relict beach ridge feature located on the mainland. It is separated from the modern barrier island, Bogue Banks, by Bogue Sound. Seventeen cores along shore-normal and shore-parallel transects provided material for sedimentologic and foraminiferal analysis and resulted in the recognition of seven depositional facies representing a variety of coastal depositional environments. Chronologic and depositional facies data suggest the CBRC was initiated during MIS 5a and rapid southward progradation produced a cape structure. Eolian reactivation of the upper sand of the CBRC occurred during the last glacial maximum (∼18 ka). The age of flood tide delta deposits in Bogue Sound suggests that the Holocene barrier island, Bogue Banks, had formed by ∼6 ka. Shoreface ravinement resulted in a shoreface landward of the present shoreline by ∼3.5 ka. Seaward and westward spit progradation of Bogue Banks began ∼1.7 ka and continued to ∼1.3 ka. Normal marine salinity conditions were present in Bogue Sound ∼1.1 ka, suggesting removal of at least the narrowest parts of the barrier island, coeval with a previously documented segmentation of the southern Outer Banks barrier islands. Previous work has linked this segmentation to climate warming and increased tropical storm activity during the Medieval Climate Anomaly. This study illustrates the complex response of this coastal system to Pleistocene and Holocene sea-level and climate change over two major sea-level cycles. In particular, the regional geomorphology during MIS5a and the Holocene sea-level highstand differ significantly and this, in large part, was controlled by the antecedent geologic framework, resulted in the contrasting more localized coastal geomorphic response.

  4. Deposition by the 2011 Tohoku-oki tsunami on coastal lowland controlled by beach ridges near Sendai, Japan

    NASA Astrophysics Data System (ADS)

    Takashimizu, Yasuhiro; Urabe, Atsushi; Suzuki, Koji; Sato, Yoshiki

    2012-12-01

    A study of the 2011 Tohoku-oki tsunami deposits on the coastal lowland of the Sendai Plain, Japan was carried out along a shore-perpendicular survey line in the Arahama area. Field descriptions and tsunami water depth measurements were complemented by sedimentary analyses, including grain size, grain fabric and diatom analysis. The tsunami deposits show a generally fining-inland trend along the 3.4 km long transect. The depositional facies, grain size analysis and grain fabric data suggest that most of the tsunami deposits were laid down during the tsunami inflow, except at one site. These tsunami deposits are characterized by parallel-laminated or massive sand and silt with pieces of woods, fragments of glass, rip-up mud clasts and an erosional base. Minor backwash deposits overlying the inflow sand layer were only observed on one beach ridge and attributed to the topographic high. Marine diatom species comprised only approximately 2% of the diatom assemblage in tsunami deposits and their content decreased landward. In this study, diatom assemblages were similar in the rice field soil and tsunami layers, suggesting that the muddy fraction of the deposits mainly consists of sediments derived from the tsunami-eroded rice field soil. As a result of soil erosion, the tsunami had a high suspended sediment load. Furthermore, after the first tsunami inundation, seawater left by the tsunami did not drain completely to the sea because of the high coastal beach ridge and/or coastal subsidence due to the massive earthquake. Therefore, strong tsunami outflows to the sea did not occur and these areas were covered by mud deposited from stagnant water.

  5. Late Quaternary development of the Croatan Beach Ridge Complex, Bogue Sound, Bogue Banks, NC, USA and implications for coastal evolution

    NASA Astrophysics Data System (ADS)

    Lazar, Kelly B.; Mallinson, David J.; Culver, Stephen J.

    2016-06-01

    Foraminiferal, sedimentological, geophysical, and geochronologic data were utilized to elucidate the late Quaternary geologic development of the Croatan Beach Ridge Complex (CBRC), Bogue Sound, and Bogue Banks, North Carolina, USA. The CBRC is a relict beach ridge feature located on the mainland. It is separated from the modern barrier island, Bogue Banks, by Bogue Sound. Seventeen cores along shore-normal and shore-parallel transects provided material for sedimentologic and foraminiferal analysis and resulted in the recognition of seven depositional facies representing a variety of coastal depositional environments. Chronologic and depositional facies data suggest the CBRC was initiated during MIS 5a and rapid southward progradation produced a cape structure. Eolian reactivation of the upper sand of the CBRC occurred during the last glacial maximum (∼18 ka). The age of flood tide delta deposits in Bogue Sound suggests that the Holocene barrier island, Bogue Banks, had formed by ∼6 ka. Shoreface ravinement resulted in a shoreface landward of the present shoreline by ∼3.5 ka. Seaward and westward spit progradation of Bogue Banks began ∼1.7 ka and continued to ∼1.3 ka. Normal marine salinity conditions were present in Bogue Sound ∼1.1 ka, suggesting removal of at least the narrowest parts of the barrier island, coeval with a previously documented segmentation of the southern Outer Banks barrier islands. Previous work has linked this segmentation to climate warming and increased tropical storm activity during the Medieval Climate Anomaly. This study illustrates the complex response of this coastal system to Pleistocene and Holocene sea-level and climate change over two major sea-level cycles. In particular, the regional geomorphology during MIS5a and the Holocene sea-level highstand differ significantly and this, in large part, was controlled by the antecedent geologic framework, resulted in the contrasting more localized coastal geomorphic response.

  6. Ground-penetrating radar (GPR) stratigraphy of late-Pleistocene relict foredunes on a coastal barrier: Matakana Island, New Zealand

    NASA Astrophysics Data System (ADS)

    Brook, M.; Shepherd, M.; Tinkler, R.; Williams, J.

    2012-04-01

    Matakana Island, North Island, New Zealand, forms a c. 24 km long barrier island between the Bay of Plenty and Tauranga Harbour, which it encloses. The island is of two distinct parts, with the larger seaward part comprising a Holocene sand barrier, extending parallel to the shoreline, and a harbourward (Pleistocene) part, adjoining the centre of the Holocene barrier. The Pleistocene section of the barrier consists of three terraces at 10, 40 and 70 m above sea level, although the precise process-origin and significance of the features are unknown. We focus on the relatively flat lowest (1.0-1.5 km wide) terrace, as oblique aerial photography indicates the presence of subdued ridges (amplitude 1 m) trending NW-SE, parallel to the current coastline. An investigation of this lower terrace using a 100 MHz pulseEKKO ground penetrating radar (GPR) along a 1 km SW-NE profile normal to the axis of the subdued ridges was undertaken. Following topographic correction, the profile revealed a continuous undulating reflector at 8-12 m depth, which corresponds with the low ridges visible on the surface. The ridge-and-swale nature of the reflector, coupled with the surface topography indicates it represents a relict foredune plain, mainly below present-day sea level. The age of the relict foredune plain is intriguing, with a maximum age of 780,000 due to the absence of Te Puna Ignimbrite, which is present on the higher terraces. Published maps indicate the lowest terrace is covered by lacustrine beds of the Matua Subgroup (minimum age c. 220,000 yr), yet it is difficult to reconcile the survival of ridge-and-swale foredune morphology under several metres of lacustrine deposits, suggesting that a tephra origin for the coverbeds is more likely. Nevertheless, the presence of a Pleistocene foredune plain slightly below present-day sea level indicates no significant long-term uplift, and possibly minor subsidence in this sector of the North Island.

  7. Investigation of Stinson Beach Park storm damage and evaluation of alternative shore protection measures

    SciTech Connect

    Ecker, R.M.; Whelan, G.

    1984-07-01

    An investigation was made of storm damage during the winter of 1982-83 to the National Park Service's Stinson Beach Park. The investigation included an assessment of the storm damage, evaluation of physical processes contributing to the damage, subsequent beach recovery, and the feasibility of implementing shoreline protection measure to reduce future risk. During the winter of 1982-83, the beach was almost completely denuded of sand, wave overwash damaged the foredune, vegetation on the foredune was destroyed, and backshore flooding occurred. Two structures and a parking lot were endangered as the shoreline receded. Subsequent recovery of the park beach was rapid. By January 1982 sand had moved back onshore and a beach berm was beginning to reform. The foredune and dune vegetation received the only permanent damage. Four shoreline protection alternatives were evaluated. These include no action, dune development/enhancement, construction of a rock riprap revetment, and offshore installation of artificial seaweed. The first costs (estimated costs, excluding maintenance) range from about $90,000 to $475,000. The least-cost protection measure is riprap revetment, which protects the two structures and parking lot endangered during the 1982-83 winter storms. Construction of a foredune along the entire park beach is the highest cost protection measure. If no shore protection action measures are implemented, wave overwash of the foredune can be expected to occur on the average of every 2 to 3 years, and beach degradation, similar to that during the 1982-83 winter, can be expected to occur on the average of every 10 to 12 years. 12 references, 19 figures, 18 tables.

  8. Towards increasing the spatial resolution of luminescence chronologies - Portable luminescence reader measurements and standardized growth curves applied to the beach-ridge plain of Phra Thong Island, Thailand

    NASA Astrophysics Data System (ADS)

    Brill, Dominik; Jankaew, Kruawun; Brückner, Helmut

    2016-04-01

    Since optically stimulated luminescence (OSL) dating is time consuming and cost intensive, age information available for individual study sites is usually restricted to significantly less than 100 ages. In particular the interpretation of complex depositional systems with temporally and spatially diverse sedimentation histories may suffer from the effects of a poor spatial resolution or an ineffective distribution of chronological data. In these cases, time and cost efficient approaches that provide reasonable dating accuracy are required to substitute or complement full luminescence dating. For the sandy beach-ridge plain of Phra Thong Island, Thailand, which is chronologically constrained by a set of approximately 50 luminescence ages, we evaluated the potential (i) of luminescence profiling using a portable luminescence reader, and (ii) of standardized growth curves (SGCs) to improve the resolution and sampling strategy of OSL dating in coastal settings. Although SGCs are related to some shortcomings in dating accuracy, and luminescence profiling with even the favorable conditions provided by the homogeneous sandy stratigraphy of the beach-ridge plain does not equal full luminescence dating, both approaches are capable of reproducing some of the main chronostratigraphic features of the island. This includes the differentiation between Holocene and last interglacial ridges, as well as the identification of the general east-west progradation and some (but not all) of several 1500-2000 year hiatuses within the Holocene sediment succession. However, while both approaches can successfully identify relative chronological trends, robust absolute age estimates can only be achieved by considering the highly variable dosimetry, which is the main contributing factor to bulk luminescence signals apart from deposition age on Phra Thong Island. At Phra Thong, portable reader signals as a proxy for palaeodoses combined with sample-specific dose rates proved as the best

  9. Preliminary geochemical data on shallow marine mollusc from middle Pleistocene-Holocene beach ridges in the gulf of S. Jorge (Patagonia, Argentina)

    NASA Astrophysics Data System (ADS)

    Consoloni, Ilaria; Zanchetta, Giovanni; Aguirre, Marina L.; Baneschi, Ilaria; Boretto, Gabriella M.; Dallai, Luigi; D'Orazio, Massimo; Fallick, Anthony E.; Isola, Ilaria; Pappalardo Adriano Ribolini, Marta

    2010-05-01

    The Patagonia coast comprised between ca 45° S and 43° S preserves a spectacular succession of Quaternary raised beach deposits mostly composed by gravelly beach-ridge successions containing abundant storm accumulations of mollusc remains. Currently, this coastal area is interested by the competing action of the warm Brazilian current from north and the Falkland (Malvinas) current from the south, and roughly it corresponds to the boundary of the Magellanean and Argentinean zooprovinces. Although paleontological studies have been conducted in the recent past (e.g. Aguirre, 2003) there are not practically geochemical studies on these natural archives to infer local paleoceanographic and paleoclimate changes. Preliminary geochemical studies (petrography, stable isotopes, trace elements) on the aragonitic shell Prototaqua antiqua collected in various localities spanning from Holocene to Middle Pleistocene (MIS 9 to MIS 1, e.g. Schellmann and Radke, 2000) successions indicate that this species is relatively well preserved and can be used for the reconstruction of the past coastal oceanographic changes in the area. Aguirre, M.L., 2003. Late Pleistocene and Holocene palaeoenvironments in Golfo San Jorge, Patagonia: molluscan evidence. Marine Geology 194, 3-30. Schellmann, G., Radtke, U., 2000. ESR dating of stratigraphically well-constrained marine terraces along the Patagonian Atlantic coast (Argentina). Quaternary International 68/71, 261-273.

  10. Coastal foredune evolution: the relative influence of vegetation and sand supply in the US Pacific Northwest.

    PubMed

    Zarnetske, Phoebe L; Ruggiero, Peter; Seabloom, Eric W; Hacker, Sally D

    2015-05-01

    Biophysical feedbacks between vegetation and sediment are important for forming and modifying landscape features and their ecosystem services. These feedbacks are especially important where landscape features differ in their provision of ecosystem services. For example, the shape of coastal foredunes, a product of both physical and biological forces, determines their ability to protect communities from rising seas and changing patterns of storminess. Here we assessed how sand supply and changes in vegetation over interannual (3 year) and decadal (21 year) scales influenced foredune shape along 100 km of coastline in the US Pacific Northwest. Across 21 years, vegetation switched from one congeneric non-native beachgrass to another (Ammophila arenaria to A. breviligulata) while sand supply rates were positive. At interannual timescales, sand supply rates explained the majority of change in foredune height (64-69%) and width (56-80%). However, at decadal scales, change in vegetation explained the majority of the change in foredune width (62-68%), whereas sand supply rates explained most of the change in foredune height (88-90%). In areas with lower shoreline change rates (±2 m yr(-1)), the change in vegetation explained the majority of decadal changes in foredune width (56-57%) and height (59-76%). Foredune shape directly impacts coastal protection, thus our findings are pertinent to coastal management given pressures of development and climate change. PMID:25833242

  11. Coastal foredune evolution: the relative influence of vegetation and sand supply in the US Pacific Northwest

    PubMed Central

    Zarnetske, Phoebe L.; Ruggiero, Peter; Seabloom, Eric W.; Hacker, Sally D.

    2015-01-01

    Biophysical feedbacks between vegetation and sediment are important for forming and modifying landscape features and their ecosystem services. These feedbacks are especially important where landscape features differ in their provision of ecosystem services. For example, the shape of coastal foredunes, a product of both physical and biological forces, determines their ability to protect communities from rising seas and changing patterns of storminess. Here we assessed how sand supply and changes in vegetation over interannual (3 year) and decadal (21 year) scales influenced foredune shape along 100 km of coastline in the US Pacific Northwest. Across 21 years, vegetation switched from one congeneric non-native beachgrass to another (Ammophila arenaria to A. breviligulata) while sand supply rates were positive. At interannual timescales, sand supply rates explained the majority of change in foredune height (64–69%) and width (56–80%). However, at decadal scales, change in vegetation explained the majority of the change in foredune width (62–68%), whereas sand supply rates explained most of the change in foredune height (88–90%). In areas with lower shoreline change rates (±2 m yr−1), the change in vegetation explained the majority of decadal changes in foredune width (56–57%) and height (59–76%). Foredune shape directly impacts coastal protection, thus our findings are pertinent to coastal management given pressures of development and climate change. PMID:25833242

  12. Morphodynamics of Prograding Beaches

    NASA Astrophysics Data System (ADS)

    Ruggiero, P.

    2012-12-01

    Long-term coastal evolution often results from the cumulative effects of small residual differences between relatively large signals. In light of dire projections of sea level rise over the next several decades to century, there is a strong societal need for accurate forecasts of net interannual- to decadal-scale coastal change. However, our present understanding of the processes responsible for storm-induced erosion and coastal recession is significantly more advanced than our knowledge of coastal recovery during calm periods. To investigate the processes and morphodynamics associated with progading beaches we synthesize findings from a long-term (15 years) beach morphology monitoring program in the U.S. Pacific Northwest. Most of the beaches along the Columbia River littoral cell (northwest Oregon and southwest Washington) were eroded during the two intense winters of 1997/1998 (a major El Niño event) and 1998/1999 (a moderate La Niña event). Subsequent to these winters the beaches have exhibited net residual progradation of several meters per year resulting in significant shoreline advance. During this same period as many as two to three new foredunes formed with backshore beach profiles accumulating sand at rates of well over 10 m3/m/yr. Interestingly, these large signals of horizontal and vertical coastal advance have occurred on beaches in which nearshore morphological variability is dominated by net offshore sandbar migration. Net offshore sandbar migration follows a three-stage process; bar generation near the shoreline, seaward migration, and bar degeneration in the outer nearshore with a cyclic return period of approximately 4 to 5 years in the region. Gradients in alongshore sediment transport, net onshore directed cross-shore sediment transport within the surf zone, and cross-shore feeding from a shoreface out of equilibrium with forcing conditions may each be partially responsible for the sediment supplied to the beaches and dunes during the study

  13. Coastal Dune Building Capabilities of Native and Exotic Beach Grasses: Initial Results From a Moveable Bed Wind Tunnel Experiment

    NASA Astrophysics Data System (ADS)

    Zarnetske, P. L.; Seabloom, E. W.; Ruggiero, P.; Hacker, S. D.; Killian, J.; Maddux, T.; Cox, D.; Pattanapol, W.; Bokil, V.

    2008-12-01

    Coastal dune morphology results from the interplay between wind, waves, sediment supply, and vegetation. Over the last 100 years in the U.S. Pacific Northwest, two exotic beach grasses (Ammophila arenaria and A. breviligulata) have replaced much of the native beach grass (Elymus mollis), and formed large continuous, and relatively stable, foredunes where open low-lying dynamic dune systems had previously dominated. Field measurements demonstrate a correlation between dominant beach grass species and foredune height, suggesting the potential for an ecological control on coastal vulnerability. Over a 20 year period, and across a broad range of sediment supply along the coast, A. breviligulata is associated with lower foredune heights than A. arenaria. Based on these correlations, we hypothesize that the A. arenaria is more effective at entrapping and stabilizing sand which results in steep and tall foredune morphology along reaches where this species dominates. A moveable bed wind tunnel experiment is being performed at Oregon State University's O.H. Hinsdale Wave Research Laboratory to test this hypothesis. Our experiments will quantify the relative sand trapping capabilities among the three beach grass species across different planting densities and wind speeds. Results from the experiment will help parameterize a computational fluid dynamics model describing dune building capabilities of different species, species' densities, wind speeds, and sediment supplies. Wind tunnel experiments and modeling results will be combined with field data, both biological and physical observations, to inform coastal protection measures and dune ecosystem management.

  14. Evolution of foredune texture following dynamic restoration, Doughboy Bay, Stewart Island, New Zealand

    NASA Astrophysics Data System (ADS)

    Konlechner, T. M.; Ryu, W.; Hilton, M. J.; Sherman, D. J.

    2015-12-01

    Growing concern regarding the geomorphic and associated biotic effects of dune management practises has led to an increase in the number of dune restoration projects globally. Most recent projects aim to enhance the efficiency of aeolian sediment dynamics and increase dune mobility by decreasing vegetation cover, but we lack objective measures to evaluate such projects. Here we demonstrate the use of landscape metrics to quantify the evolution of foredune texture following the removal of vegetation. A long-term program of marram grass (Ammophila arenaria) eradication in southern New Zealand (Doughboy Bay, Stewart Island) is examined. Four metrics: bare sand area, patch adjacency, complexity, and the range of proximity, are used to classify a series of foredune textures beginning with the pre-restoration state through the phases of marram removal, to the current state. Foredune texture at Doughboy Bay has evolved from a semi-stable to an active state as the consequence of restoration. Two metrics, bare sand and adjacency, appear to be particularly good measures of change following marram removal. Patterns and rates of change for these metrics are consistent with ground observations of increased 'naturalness' (native plant communities, sand mobility) over the same period. The set of landscape metrics derived for Doughboy Bay were compared to similar sets measured for a nearby foredune system where marram invasion has not occurred, and where conditions presumably represent equilibrium foredune texture. Since the removal of marram at Doughboy Bay and the consequent remobilization of the sand surface, the foredune texture has increased in similarity to that of the reference site, indicating a favourable shift in plant cover as a result of the restoration program. We conclude that landscape metrics can be used to track changes in foredune morphology following restoration. Second, the planning, management, and monitoring of coastal dune restoration programs will benefit

  15. A quantitative ~1ky lake level record of Lake Prespa (SW Balkans) derived from beach ridge sediments: implications for hydro-climatic changes from the Medieval Climate Anomaly to the present

    NASA Astrophysics Data System (ADS)

    van der Schriek, Tim; Giannakopoulos, Christos

    2016-04-01

    We present the first quantitative lake stage record of Prespa that covers the past millennium, based on the singular isthmus beach ridge complex, allowing numerical reconstruction of precipitation-driven inflow changes during the Medieval Climate Anomaly (MCA) and the Little Ice Age (LIA). Mediterranean precipitation change, based on lake-proxy reconstructions, shows a distinct W-E pattern over the past millennium. Generally, the West experienced drier conditions during the MCA and wetter conditions during the LIA; the East experienced opposite conditions. This pattern is linked to the multi-decadal North Atlantic Oscillation (NAO) Winter Index: positive phases are associated with drier (wetter) and negative phases with wetter (drier) conditions in the W (E) Mediterranean. The SW Balkans is located at the juncture of proposed boundary between these contrasting climate and hydrological domains. It is not clear which, if any, of these patterns reflects past precipitation changes in the region, given the lack of detailed palaeo-hydrological data. The beach ridge complex that underlies the entire isthmus separating Lakes Mikri- and Megali Prespa offers a unique opportunity to address this question. High, oblique, sediment-supply allows the formation and preservation of beach ridges that register the annual water level fluctuations of Lake Megali Prespa which are driven by wet season precipitation and contain a strong NAO-signal. Modern beach-ridge sediment facies were calibrated against observed lake levels, thus allowing the reliable determination of past lake levels from the geological record. Lake surface area variation was found to be a more reliable indicator of hydro-climate change than water level fluctuations as the latter are strongly influenced by lake bathymetry. Accordingly, surface areas were calculated for different water levels to enable the conversion of lake level stage-indicators to quantitative inflow estimates. The isthmus profile reveals a "high

  16. Beach-cusp formation

    USGS Publications Warehouse

    Sallenger, A.H., Jr.

    1979-01-01

    Field experiments on beach-cusp formation were undertaken to document how the cuspate form develops and to test the edge-wave hypothesis on the uniform spacing of cusps. These involved observations of cusps forming from an initially plane foreshore. The cuspate form was observed to be a product of swash modification of an intertidal beach ridge as follows. A ridge, cut by a series of channels quasi-equally spaced along its length, was deposited onto the lower foreshore. The ridge migrated shoreward with flood tide, while the longshore positions of the channels remained fixed. On ebb tide, changes in swash circulation over the ridge allowed the upwash to flow shoreward through the channels and the channel mouths were eroded progressively wider until adjacent mouths met, effecting a cuspate shape. Measured spacings of cusps, ranging in size from less than 1 m to more than 12 m, agree well with computed spacings due to either zero-mode subharmonic or zero-mode synchronous edge waves. Edge-wave-induced longshore variations in run up will cause water ponded behind a ridge to converge at points of low swash and flow seaward as relatively narrow currents eroding channels spaced at one edge-wave wavelength for synchronous edge waves or one half wavelength for subharmonic edge waves. The channels are subsequently modified into cusp troughs as described above.

  17. Quantifying the effects of European beach grass on aeolian sand transport over the last century: Bodega Marine Reserve, California

    NASA Astrophysics Data System (ADS)

    Cesmat, R.; Werner, S.; Smith, M. E.; Riedel, T.; Best, R.; Olyarnik, S.

    2012-12-01

    Introduction of European beach grass (Ammophila arenaria) to coastal dune systems of western North America induced significant changes to the transport and storage of sediment, and consequently the nesting habitat of the western snowy plover (Charadrius alexandrinus nivosus). At the Bodega Marine Reserve and Sonoma Coast State Park, Ammophila was introduced within the ~0.5 km2 dune area in the 1920's to limit the flux of sand through Bodega Harbor and agricultural land. To assess the potential impact of restoration efforts (Ammophila removal) on aeolian sediment flux, we measured sediment flux as a function of wind speeds and ground cover, and used these measurements to parameterize a spatial model for historical sand deposition Fine- to coarse-grained lithic to sub-lithic sand is delivered to the Bodega dune system from Salmon Creek beach, the down-shore terminus of a littoral system fed by the 3846 km2 Russian River catchment, several small (<100 km2) coastal catchments, and seacliff erosion. Littoral sediment traverses the 1.8 km wide dune system from NW to SE via aeolian transport. Ammophila colonization occurred initially adjacent to the shoreface, inducing deposition of a ~10 meter-high foredune and has subsequently encroached the ~0.5 km2 region between the foredune and Bodega Harbor. Comparison of historical topographic maps via raster subtraction indicates rapid construction of both the foredune and a ~15 meter-high transverse dune (Gaffney ridge) at the edge of the planted region. An average accumulation rate of ~4,000 m3/yr is indicated within the study swath by the preserved sediment volumes. Within the modern dune system, unvegetated areas exhibit 2-3 meter wavelength, ~1/2 meter amplitude mega-ripples, and the uppermost 2-10 cm consists of coarse-sand to granule-sized armor layer. In contrast, grain-sizes in vegetated areas are largely vertically homogenous. Open areas are typically 2-8 meters lower than adjacent vegetated areas, and show evidence for

  18. Beach ridges as paleoseismic indicators of abrupt coastal subsidence during subduction zone earthquakes, and implications for Alaska-Aleutian subduction zone paleoseismology, southeast coast of the Kenai Peninsula, Alaska

    USGS Publications Warehouse

    Kelsey, Harvey M.; Witter, Robert C.; Engelhart, Simon E.; Briggs, Richard; Nelson, Alan R.; Haeussler, Peter J.; Corbett, D. Reide

    2015-01-01

    The Kenai section of the eastern Alaska-Aleutian subduction zone straddles two areas of high slip in the 1964 great Alaska earthquake and is the least studied of the three megathrust segments (Kodiak, Kenai, Prince William Sound) that ruptured in 1964. Investigation of two coastal sites in the eastern part of the Kenai segment, on the southeast coast of the Kenai Peninsula, identified evidence for two subduction zone earthquakes that predate the 1964 earthquake. Both coastal sites provide paleoseismic data through inferred coseismic subsidence of wetlands and associated subsidence-induced erosion of beach ridges. At Verdant Cove, paleo-beach ridges record the paleoseismic history; whereas at Quicksand Cove, buried soils in drowned coastal wetlands are the primary indicators of paleoearthquake occurrence and age. The timing of submergence and death of trees mark the oldest earthquake at Verdant Cove that is consistent with the age of a well documented ∼900-year-ago subduction zone earthquake that ruptured the Prince William Sound segment of the megathrust to the east and the Kodiak segment to the west. Soils buried within the last 400–450 years mark the penultimate earthquake on the southeast coast of the Kenai Peninsula. The penultimate earthquake probably occurred before AD 1840 from its absence in Russian historical accounts. The penultimate subduction zone earthquake on the Kenai segment did not rupture in conjunction with the Prince William Sound to the northeast. Therefore the Kenai segment, which is presently creeping, can rupture independently of the adjacent Prince William Sound segment that is presently locked.

  19. Latest Holocene Mapping of Tsunamigenically- and Seismogenically-Influenced Beach, Dune and Fluvial Landforms at Tolowa Dunes State Park, Northwestern California

    NASA Astrophysics Data System (ADS)

    Vaughan, P. R.

    2015-12-01

    Beach, dune, fluvial, and marine terrace deposits comprise a 16 kilometer (km) coastal strip immediately south of the Smith River at Tolowa Dunes State Park (TDSP), ~ 3.5 km north-northwest from downtown Crescent City, California. The park has numerous Native American sites that are vulnerable to sea level rise and coastal erosion, part of which may be influenced by Cascadia interseismic deformation. Efforts at removal of exotic beach grass (Ammophila arenaria) that stabilizes most of the dune complex have begun; vegetation removal will remobilize the dunes and could obscure and also expose near surficial geologic features. Using a LiDAR base to capture extant data and give context to future resource protection projects, I surficially mapped the dunes and provisionally interpreted, tsunamigenically-derived cobbles (which are more than five feet thick in one road cut exposure) that extensively mantle the deflation plain in the lee of the foredune. Natural, test pit and auger exposures helped characterize fluvial and marsh deposits in the southern bank and floodplain of the Smith River. Optically stimulated luminescence and/or radiocarbon dates constrain the ages for cobble deposits and dunes throughout the park, and liquefaction features exposed in the southern bank of the Smith River. In combination with estimated rates of dune formation and migration at TDSP since the A.D. 1700 Cascadia earthquake, the ages for seismogenically-sourced sediment associated with dune ridges and cobble deposits are tentatively correlated with the ages of latest Holocene Cascadia triggered turbidites dated by Goldfinger et al. (2012) on the Smith River platform. The mapping also helped identify a marine terrace sequence on the southern limb of the northwest-trending Lake Earl Syncline that bifurcates the park, and suggests projection of the northwest-trending Cemetery Scarp, part of the Point St. George fault complex (Polenz and Kelsey 1999), through the southern part of the park.

  20. Evidence for change in climate variability during the late-holocene inferred from a sequence of Lake Michigan dune ridges

    SciTech Connect

    Lichter, J. )

    1994-06-01

    The timing of ridge formation at a sequence of northern Lake Michigan foredune ridges was calibrated with the historical lake-level record and with climate records to reconstruct a history of climate-related lake-level variation. Foredune ridges are constructed during receding and low lake levels related to regional drought. Shore recession during high lake levels may promote eolian erosion which modifies the shore-parallel foredune ridges into parabolic dunes. A chronology of ridge formation over the last 2400 years indicates that parabolic dunes developed only during periods of frequent ridge formation and drought. Analysis of ridge formation during the historical record of lake-level variation suggest that this association results from increase variability in regional water balances as opposed to variation in sediment supply. Periods of high variability in regional water balances occurred between 380 BC and AD 20, AD 20, AD 20-300, AD 880-990, AD 1180-1280, and AD 1520-1650.

  1. Holocene geoarchaeology of the Sixteen Mile Beach barrier dunes in the Western Cape, South Africa

    NASA Astrophysics Data System (ADS)

    Compton, John S.; Franceschini, Giuliana

    2005-01-01

    Holocene evolution and human occupation of the Sixteen Mile Beach barrier dunes on the southwest coast of South Africa between Yzerfontein and Saldanha Bay are inferred from the radiocarbon ages of calcareous dune sand, limpet shell ( Patella spp.) manuports and gull-dropped white mussel shells ( Donax serra). A series of coast-parallel dunes have prograded seaward in response to an overall marine regression since the mid-Holocene with dated shell from relict foredunes indicating periods of shoreline progradation that correspond to drops in sea level at around 5900, 4500 and 2400 calibrated years before the present (cal yr B.P.). However, the active foredune, extensively covered by a layer of gull-dropped shell, has migrated 500 m inland by the recycling of eroded dune sand in response to an approximate 1 m sea level rise over the last 700 yr. Manuported limpet shells from relict blowouts on landward vegetated dunes indicate human occupation of coastal dune sites at 6200 and 6000 cal yr B.P. and help to fill the mid-Holocene gap in the regional archaeological record. Coastal midden shells associated with small hearth sites exposed in blowouts on the active foredune are contemporaneous (1600-500 cal yr B.P.) with large midden sites on the western margin of Langebaan Lagoon and suggest an increase in marine resource utilisation associated with the arrival of pastoralism in the Western Cape.

  2. Stability and bistability in a one-dimensional model of coastal foredune height

    NASA Astrophysics Data System (ADS)

    Goldstein, Evan B.; Moore, Laura J.

    2016-05-01

    On sandy coastlines, foredunes provide protection from coastal storms, potentially sheltering low areas—including human habitat—from elevated water level and wave erosion. In this contribution we develop and explore a one-dimensional model for coastal dune height based on an impulsive differential equation. In the model, coastal foredunes continuously grow in a logistic manner as the result of a biophysical feedback and they are destroyed by recurrent storm events that are discrete in time. Modeled dunes can be in one of two states: a high "resistant-dune" state or a low "overwash-flat" state. The number of stable states (equilibrium dune heights) depends on the value of two parameters, the nondimensional storm frequency (the ratio of storm frequency to the intrinsic growth rate of dunes) and nondimensional storm magnitude (the ratio of total water level during storms to the maximum theoretical dune height). Three regions of phase space exist (1) when nondimensional storm frequency is small, a single high resistant-dune attracting state exists; (2) when both the nondimensional storm frequency and magnitude are large, there is a single overwash-flat attracting state; (3) within a defined region of phase space model dunes exhibit bistable behavior—both the resistant-dune and the low overwash-flat states are stable. Comparisons to observational studies suggest that there is evidence for each state to exist independently, the coexistence of both states (i.e., segments of barrier islands consisting of overwash-flats and segments of islands having large dunes that resist erosion by storms), as well as transitions between states.

  3. Beach profile variation on Hawaiian carbonate beaches

    USGS Publications Warehouse

    Gibbs, A.E.; Richmond, B.M.; Fletcher, C.H.

    2000-01-01

    Beach profiles from selected Oahu and Maui beaches quantitatively document beach volume variation and change between 1994 and 1999. Along exposed, high-energy beaches, large fluctuations in beach volume, characterized primarily by the formation and erosion of extensive berms, dominate the seasonal changes. Beaches along more protected stretches of coastline show much less variation in profile morphology. Beaches on the west (leeward) coast of Oahu experienced the most seasonal variation in profile volume, followed by the north shore, east (windward) shore, and south shore. Similar to Oahu, beaches along the west coast of Maui showed the greatest overall profile variation. However, the mean variation for profiles along a single coastal reach showed little difference compared to other coastal segments. Although some beaches showed net gain or loss during the study period, most beaches remained relatively stable with change limited to a finite envelope. No island-wide trends in beach erosion or accretion were observed during the study period. However, no extreme events, such as tropical storms or hurricanes, directly influenced the Hawaiian Islands during the study period. This data set should therefore be considered as representative of typical annual beach activity. Greater variation and possible long-term change would be expected during extreme events.

  4. Reconstruction of Holocene coastal foredune progradation using luminescence dating — An example from the Świna barrier (southern Baltic Sea, NW Poland)

    NASA Astrophysics Data System (ADS)

    Reimann, Tony; Tsukamoto, Sumiko; Harff, Jan; Osadczuk, Krystyna; Frechen, Manfred

    2011-09-01

    Two sandy spits on the Świna barrier (Wolin and Uznam) provide a very detailed succession of Holocene coastal foredunes and dunes and are regarded as key sites along the southern Baltic Sea coast. Optically Stimulated Luminescence (OSL) dating is proven to be a powerful tool for the reconstruction of Holocene coastal spit evolution and foredune accretion; quartz extracted from the coastal sediments in the study area provides excellent properties for OSL dating. The OSL age from the innermost dune indicates that spit development of the Świna barrier started immediately after rapid sea-level rise of the Littorina transgression decelerated at ~ 6.6 ka. A significant change in the foredune progradation rate occurred during the late Subatlantic transgression at ~ 1.2 ka (800 AD), when migration rates decreased from 2.6 ± 0.7 m a - 1 to 1.3 ± 0.4 m a - 1 . Progradation accelerated again during the "Little Ice Age" between 1550 and 1850 AD. The systematic dating of 28 samples reveals six hiatuses during foredune succession, at ~ 2100 BC, ~ 900 BC, 200 BC-200 AD, ~ 600 AD, ~ 1000 AD, and ~ 1600 AD. The timing of these hiatuses correlates with the phases of transgressive dune development in the surrounding area (Troszyn and Świna) and with phases of increased aeolian activity in other parts of North- and West-Europe. We conclude that four of these phases of foredune erosion/instability and aeolian sediment mobilisation were caused by general climate shifts to cooler and stormier conditions at ~ 2200 BC, ~ 900 BC, ~ 600 AD, and at ~ 1600 AD, the latter corresponding to the "Little Ice Age". The period of increased aeolian activity around 1000 AD is probably to a phase of intensive forest clearance in Central Europe. In contrast, the systematic foredune accretion and foredune plain growth correlates to periods of positive sediment budget, milder and calmer climate, and an intact vegetation cover.

  5. Behaviour of Talitrus saltator (Crustacea: Amphipoda) on a rehabilitated sandy beach on the European Atlantic Coast (Portugal)

    NASA Astrophysics Data System (ADS)

    Bessa, Filipa; Rossano, Claudia; Nourisson, Delphine; Gambineri, Simone; Marques, João Carlos; Scapini, Felicita

    2013-01-01

    Environmental and human controls are widely accepted as the main structuring forces of the macrofauna communities on sandy beaches. A population of the talitrid amphipod Talitrus saltator (Montagu, 1808) was investigated on an exposed sandy beach on the Atlantic coast of Portugal (Leirosa beach) to estimate orientation capabilities and endogenous rhythms in conditions of recent changes in the landscape (artificial reconstruction of the foredune) and beach morphodynamics (stabilization against erosion from the sea). We tested sun orientation of talitrids on the beach and recorded their locomotor activity rhythms under constant conditions in the laboratory. The orientation data were analysed with circular statistics and multiple regression models adapted to angular distributions, to highlight the main factors and variables influencing the variation of orientation. The talitrids used the sun compass, visual cues (landscape and sun visibility) to orient and the precision of orientation varied according to the tidal regime (rising or ebbing tides). A well-defined free-running rhythm (circadian with in addition a bimodal rhythmicity, likely tidal) was highlighted in this population. This showed a stable behavioural adaptation on a beach that has experienced a process of artificial stabilization of the dune through nourishment actions over a decade. Monitoring the conditions of such dynamic environments and the resilience capacity of the inhabiting macroinfauna is a main challenge for sandy beach ecologists.

  6. Scale dependent behavior the foredune: Implications for barrier island response to storms and sea level rise

    NASA Astrophysics Data System (ADS)

    Houser, C.; Wernette, P. A.; Weymer, B. A.

    2015-12-01

    The impact of elevated storm surge on a barrier island tends to be considered from a single cross-shore dimension and dependent only on the relative elevations of the storm surge and dune. However, the foredune line is rarely uniform and can exhibit considerable variation in height and width alongshore at a range of length scales ranging from tens of meters to several kilometers. LiDAR data from Santa Rosa Island in northwest Florida, Padre Island, Texas and Assateague Island, Maryland are used to explore how the dune morphology varies alongshore and how this variability is altered by storms and post-storm recovery. While the alongshore variation in dune height can be approximated by a power law, there are scale-dependent variations in the dune that exhibit different responses to storm erosion and post-storm recovery. This suggests that the alongshore variation in dune morphology reflects the history of storm impact and recovery, and that changes in the variance magnitude through time may provide insight into whether the island will be resilient as it transgresses with rising sea level. The difference in variance magnitude at large spatial scales is associated with the framework geology unique to each island and a dominant control on island response to sea level rise.

  7. Seafloor off Natural Bridges State Beach, Santa Cruz, California

    USGS Publications Warehouse

    Storlazzi, Curt D.; Golden, Nadine E.; Gibbons, Helen

    2013-01-01

    The seafloor off Natural Bridges State Beach, Santa Cruz, California, is extremely varied, with sandy flats, boulder fields, faults, and complex bedrock ridges. These ridges support rich marine ecosystems; some of them form the "reefs" that produce world-class surf breaks. Colors indicate seafloor depth, from red-orange (about 2 meters or 7 feet) to magenta (25 meters or 82 feet).

  8. Shoreface storm morphodynamics and mega-rip evolution at an embayed beach: Bondi Beach, NSW, Australia

    NASA Astrophysics Data System (ADS)

    McCarroll, R. Jak; Brander, Robert W.; Turner, Ian L.; Leeuwen, Ben Van

    2016-03-01

    Embayed beach dynamics differ from open beaches due to the nature of headland control. Their resultant morphologies and morphodynamic behaviour are poorly understood due in part to a critical lack of surfzone and nearshore bathymetry observations. This study describes the morphodynamic storm response of a high-energy intermediate, 850 m long embayed beach over a three week period spanning a cluster of storms. A headland and subaqueous ridge protects the northern end of the beach, resulting in an alongshore wave height gradient. Contrary to existing beach state conceptual models, under energetic forcing the beach did not 'reset' or enter a 'cellular mega-rip' beach state. The protected northern end persisted in a low energy state, while the wave exposed southern section transitioned from transverse-bar-and-rip to a complex double-bar system, a process previously undescribed in the literature. Bar-rip morphology at the exposed end of the beach migrated offshore to greater depths, leaving an inner-reflective beach and longshore trough, while a mega-rip channel with 3 m relief developed at the exposed headland. The number of rip channels remained near constant over multiple storm events. Offshore sediment flux was 350 m3/m at the exposed headland and 20 m3/m at the protected end. Alongshore bathymetric non-uniformity decreased over the sub-aerial beach and inner surfzone, but increased in the outer surfzone and beyond. Suggested mechanisms for the persistence of 3D morphology during the cluster of storms include: (i) wave refraction to shore normal within the embayment; (ii) alongshore energy gradients; and (iii) pre-existing bar-rip morphology. Formation of the complex multi-bar state may be related to antecedent morphology, headland geometry, substrate gradient and localised hydrodynamic interactions near the headland. A new conceptual embayed beach state model is proposed for asymmetric, transitional embayed beaches. The model describes a pre-storm embayment where

  9. BEACHES HEALTH SURVEY

    EPA Science Inventory

    Baterial samples were taken at swimming beaches (primarily freshwater beaches) in Region 10 while evaluating potential bacterial sources (e.g., people, cattle, pets, septic systems, runoff, birds). For each beach selected, the preferred sampling is: background, low/no use period...

  10. Virtual Beach Manager Toolset

    EPA Science Inventory

    The Virtual Beach Manager Toolset (VB) is a set of decision support software tools developed to help local beach managers make decisions as to when beaches should be closed due to predicted high levels of water borne pathogens. The tools are being developed under the umbrella of...

  11. Video monitoring of meso-scale aeolian activity on a narrow beach

    NASA Astrophysics Data System (ADS)

    Hage, Pam; Ruessink, Gerben

    2014-05-01

    The morphologic evolution of coastal dunes is inextricably linked to the neighbouring beach through the incessant exchange of sand. Intense storm-wave processes erode the foredune within a few hours and transport its sand sand seaward, while aeolian processes return the eroded sand from the beach into the dune system, although at a much lower pace (months to years, or meso scale). Here we use an 8-year long data set of half-hourly snapshot video images, collected from an ≡ 50 m high tower on Egmond Beach (The Netherlands), and a concurrent meteorological and water level data set, to examine which factors affect aeolian sand delivery into the dunes. Egmond is a north-south oriented, micro- to meso-tidal, wave-dominated site that faces the North Sea. Its beach is relatively narrow ( ~ 100 m at spring low tide) and mildly sloping (~ 1 : 30), and consists of quartz sand with a median diameter of about 300 μm. Aeolian activity is clearly visible on the images as sand streamers and, in particular, sand strips, defined as low-amplitude, large-wavelength and slipfaceless deposits that migrate slowly in the wind direction and, depending on wind direction, can have orientations from almost shore-parallel to shore-normal. Beach width in combination with wind direction appeared to be the dominant factors in controlling aeolian activity. Many high wind (>≡ 13 m/s) events, especially from the west and northwest, were associated with a storm surge that inundated almost the entire beach with, accordingly, no possibility for aeolian transport. In contrast, sand-strip fields covered the entire beach during medium wind (≡ 12 - 13 m/s) events, especially when the wind was nearly shore-parallel. Many sand-strip events were observed to be regulated by the tide. Prominent sand-strip fields on the intertidal and upper beach were largely limited to low-tide situations with a wide beach, with a rising tide obviously destroying the intertidal sand strips and sometimes also negatively

  12. VIEW OF THE AREA BETWEEN THE BEACH (LEFT) AND BEACH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF THE AREA BETWEEN THE BEACH (LEFT) AND BEACH ROAD. NOTE THE RESIDENCES ON OPPOSITE SIDE OF BEACH ROAD. VIEW FACING NORTH. - Hickam Field, Fort Kamehameha Historic Housing, Along Worchester Avenue & Hope Street, Honolulu, Honolulu County, HI

  13. Mutli-Temporal Analysis of Beach Morphology on Fire Island, NY and the Impacts of Human Alterations Within the System

    NASA Astrophysics Data System (ADS)

    Hapke, C.; Lentz, E.; Kratzmann, M.; Bradley, M.

    2007-12-01

    longshore, westward direction. Previous shoreline change studies, conducted, at a broader spatial scale, show larger cells ranging from 8 to 10 km in length. These larger undulations appear to remain somewhat stationary over decadal timescales, and thus result in chronic erosion hotspots which lead to increased requests for permits to alter the beach. The reduction in the elevation of the beach from scraping, and the relocation of material from the berm to the foredune, where it is less likely to be mobilized during seasonal events, exacerbates the erosion, and slows the pulses of material that naturally move alongshore.

  14. NHD INDEXED LOCATIONS FOR BEACH

    EPA Science Inventory

    Beach locational data for BEACH Act. Beach locations are coded onto route.drain (Transport and Coastline Reach) feature of NHD to create Point Events and Linear Events. Beach locations are coded onto region.rch (Waterbody Reach) feature of NHD to create NHD Waterbody Shapefiles...

  15. Hawaii Beach Monitoring Program: Beach Profile Data

    USGS Publications Warehouse

    Gibbs, Ann E.; Richmond, Bruce M.; Fletcher, Charles H.; Hillman, Kindra P.

    2001-01-01

    Coastal erosion is widespread and locally severe in Hawaii and other low-latitude areas. Typical erosion rates in Hawaii are in the range of 15 to 30 cm/yr (0.5 to 1 ft/yr; Hwang, 1981; Sea Engineering, Inc., 1988; Makai Ocean Engineering, Inc. and Sea Engineering, Inc.,1991). Recent studies on Oahu (Fletcher et al., 1997; Coyne et al., 1996) have shown that nearly 24%, or 27.5 km (17.1 mi) of an original 115 km (71.6 mi) of sandy shoreline (1940's) has been either significantly narrowed (17.2 km; 10.7 mi) or lost (10.3 km; 6.4 mi). Nearly one-quarter of the islands' beaches have been significantly degraded over the last half-century and all shorelines have been affected to some degree. Oahu shorelines are by far the most studied, however, beach loss has been identified on the other islands as well, with nearly 13 km (8 mi) of beach likely lost due to shoreline hardening on Maui (Makai Engineering, Inc. and Sea Engineering, Inc., 1991). Causes of coastal erosion and beach loss in Hawaii are numerous but, unfortunately, poorly understood and rarely quantified. Construction of shoreline protection structures limits coastal land loss, but does not alleviate beach loss and may actually accelerate the problem by prohibiting sediment deposition in front of the structures. Other factors contributing to beach loss include: a) reduced sediment supply; b) large storms; and, c) sea-level rise. Reduction in sand supply, either from landward or seaward (primarily reef) sources, can have a myriad of causes. Obvious causes such as beach sand mining and emplacement of structures that interrupt natural sediment transport pathways or prevent access to backbeach sand deposits, remove sediment from the active littoral system. More complex issues of sediment supply can be related to reef health and carbonate production which, in turn, may be linked to changes in water quality. Second, the accumulated effect of large storms is to transport sediment beyond the littoral system. Third

  16. BACTERIA, BEACHES AND SWIMMABLE WATERS: INTRODUCING VIRTUAL BEACH

    EPA Science Inventory

    Safe beaches meet water quality standards and are valued for their aesthetics and the recreational opportunities that they afford. In the United States recreational water quality assessments and beach closure decisions are presently based on samples of enterococci or Escherichia ...

  17. Virtual Beach: Decision Support Tools for Beach Pathogen Prediction

    EPA Science Inventory

    The Virtual Beach Managers Tool (VB) is decision-making software developed to help local beach managers make decisions as to when beaches should be closed due to predicted high levels of water borne pathogens. The tool is being developed under the umbrella of EPA's Advanced Monit...

  18. Morphodynamics of Accreting Beaches

    NASA Astrophysics Data System (ADS)

    Ruggiero, P.; Gelfenbaum, G.; Sherwood, C. R.; Kaminsky, G. M.

    2002-12-01

    Beaches along the Pacific Northwest coast of the US have been shown to have large seasonal variability in shoreline position with several 10's of meters of recession occurring during the winter (high-energy waves) and typically similar scales of beach recovery during the summer (low-energy waves). However, many beaches along the Columbia River littoral cell (northwest Oregon and southwest Washington) have exhibited net residual progradation of several meters per year over decades, resulting in significant shoreline realignment. This historical shoreline advance has been primarily due to the dispersal of sand from the flanks of the ebb-tidal deltas following jetty construction at the entrances to the Columbia River and Grays Harbor. The installation of jetties removed the shallow shoals from the influence of tidal currents, resulting in a shoreface profile that was too shallow for the inherent wave energy. Onshore transport of large quantities of sand occurred over the next several decades, decreasing through time. While much of the original source material is now exhausted, many beaches today are still rapidly accreting on inter-annual time scales. Gradients in alongshore sediment transport, net onshore directed cross-shore sediment transport within the surf zone, and cross-shore feeding from a shoreface out of equilibrium with forcing conditions may each be partially responsible for this continued accretion. The primary morphodynamic mechanism for sub-aerial beach growth, and shoreline progradation on a seasonal scale, is hypothesized to be the development, onshore migration, and welding of inter-tidal (swash) bars to the upper beach face. To investigate the processes and morphodynamics associated with accreting beaches we have completed two field experiments and are applying computational models that link measured sediment transport to wave and current forcing. Experiments completed in Spring 2001 and Summer 2002 combined process measurements with observations of

  19. Virtual Beach 3: User's Guide

    EPA Science Inventory

    Virtual Beach version 3 (VB3) is a decision support tool that constructs site-specific statistical models to predict fecal indicator bacteria (FIB) concentrations at recreational beaches. VB3 is primarily designed for beach managers responsible for making decisions regarding beac...

  20. Shoreline relaxation at pocket beaches

    NASA Astrophysics Data System (ADS)

    Turki, Imen; Medina, Raul; Kakeh, Nabil; González, Mauricio

    2015-09-01

    A new physical concept of relaxation time is introduced in this research as the time required for the beach to dissipate its initial perturbation. This concept is investigated using a simple beach-evolution model of shoreline rotation at pocket beaches, based on the assumption that the instantaneous change of the shoreline plan-view shape depends on the long-term equilibrium plan-view shape. The expression of relaxation time is developed function of the energy conditions and the physical characteristics of the beach; it increases at longer beaches having coarse sediments and experiencing low-energy conditions. The relaxation time, calculated by the developed model, is validated by the shoreline observations extracted from video images at two artificially embayed beaches of Barcelona (NW Mediterranean) suffering from perturbations of sand movement and a nourishment project. This finding is promising to estimate the shoreline response and useful to improve our understanding of the dynamic of pocket beaches and their stability.

  1. Origin of the Herman-Norcross-Tintah sequence of Lake Agassiz beaches in Manitoba, Canada

    NASA Astrophysics Data System (ADS)

    McMillan, Kyle; Teller, James T.

    2012-05-01

    The giant glacial Lake Agassiz basin is fringed by many strandlines, which have long been used to trace the paleogeography of the former lake over its 5000 year history. The oldest and highest of these strandlines were placed into three groups by Warren Upham in the 1890 s - the Herman, Norcross, and Tintah - and form a staircase of small landforms. The formation of these old strandlines began as early as ~13.9 cal (12.0 14C) kyr BP and ended ~12.8 cal (10.8 14C) kyr BP, based on OSL dates and the history of lake level in the Agassiz basin. New mapping and augering of beach ridges in southern Manitoba, Canada, associated with the earliest phase of the lake, indicate that there are a series of up to 28 small discontinuous beach ridges that are generally only a few metres high and a few tens of metres wide. These beaches mainly consist of weakly defined beds of poorly sorted sediments; in many cases a central sandy diamicton unit lies stratigraphically between overlying beach sediments and clay diamicton (till) below. Spatially, ridges are separated by silty or sandy units or gravel lags; inter-beach lagoonal organics were not found. We discuss the possible origin of these Lake Agassiz beaches, concluding that they were deposited over a few centuries by episodic storm events, as lake level slowly declined. We base this conclusion on the nature of the sediments in the beach ridges and the regional geomorphology, as well theoretical considerations about sedimentation along a regressing shoreline of a large lake. Other origins are rejected, although some other factors may have contributed to formation of some of the beaches, such as temporary increases in sediment supply, variable rate of outlet erosion, and short increases in lake-level that reworked sediment upslope into ridges. Using the time frame of 13.9 to 12.8 cal kyr BP for the formation of the beaches, the average interval between formation of each beach is ~39 years.

  2. Response to storm conditions of two different beaches at the Mediterranean coast of Morocco

    NASA Astrophysics Data System (ADS)

    El Mrini, Aldelmounim; Anfuso, Giorgio; Nachite, Driss; Taaouati, Mohamed

    2010-05-01

    In recent decades the increased demand for the recreational use of beaches has resulted in the uptake of studies on the morphodynamic processes which are acting on beaches. This knowledge is fundamental for appropriate coastal erosion management, suitable tourist use of littoral and for the design and shape of human construction. The Mediterranean sectors of Moroccan littoral investigated in this study, Ksar Rimal and Cabo Negro beaches, are respectively located north and south of Cabo Negro promontory and, over recent years, have been subject to increasing tourist activity. This has consisted mainly of the construction of two tourist ports (Marina Smir and Kabila), residential developments, hotels and a motorway which runs parallel to the coast, affecting the dune ridges and two lagoons which are of great ecological interest. In detail, the dunes located in the backshore at Ksar Rimal beach, are nowadays occupied by summer houses threaten by coastal retreat. A wide, partially urbanized, backshore is observed at Cabo Negro beach. With the intention of characterize the morphodynamic and seasonal behavior and the response of the studied beaches to storm impact, a beach monitoring program was carried out in the period 2006-2008, with special attention to the February-March 2008 stormy period. On analyzing the information obtained, it was possible to characterize the morphology and sedimentology of the studied beaches, and to calculate beach volumetric variations. Ksar Rimal is an open, exposed beach characterized by an intermediate slope (tan β = 0.10) with medium-coarse sands. The beach showed a reflective beach state characterized by plunging breakers. Small morphological seasonal changes were observed, most important morphological and volumetric variations (about 20 m3/m) taking place after winter storms which usually gave rise to a more dissipative beach profile (tan β = 0.05) characterized by spilling breakers. Beach recovery was quite rapid, usually lasting 2

  3. Getting Aquainted with Beaches and Coasts.

    ERIC Educational Resources Information Center

    DeWall, Allan E.

    1980-01-01

    Explains how a shoreline is formed and how it changes, and why its changes do not always coincide with human plans. Subjects discussed include beaches, beach processes, inlets and beaches, and a marine glossary. (Author/DS)

  4. Geomorphology and anthropogenic impact including military constraints in a microtidal wave-dominated embayment in south western Sardinia (Porto Pino beach, SCI ITB040025, Mediterranean Sea). Implications for beach management.

    NASA Astrophysics Data System (ADS)

    De Muro, Sandro; Buosi, Carla; Pusceddu, Nicola; Frongia, Paolo; Passarella, Marinella; Ibba, Angelo

    2016-04-01

    The coastal zones of the Mediterranean have undergone increasing pressure over the last century. The intensifying coastal development and the increasing tourist impact have led to an intense transformation of the coastlines and adjacent marine areas. The beach and the coastal dune play an important role in protecting the coastline. Thus, the study of its geomorphological evolution and of its anthropic modification is fundamental in order to adopt the best management practices. In this regard, the LIFE Project (LIFE13NAT/IT/001013) SOSS DUNES (Safeguard and management Of South-western Sardinian Dunes) aims to safeguard the dune habitats and the beach system in a site belonging to the Natura 2000 network, an EUwide network of nature protection areas established under the 1992 Habitats Directive. This project is focused on a microtidal wave-dominated embayment located in south western Sardinia (Italy, Mediterranean Sea) called Porto Pino beach comprised in the SCI (Site of Community Importance) "Promontory, dunes and wetland of Porto Pino (ITB040025)". This research aims to investigate the geomorphological processes, the evolution and the main human impacts on Porto Pino beach as an useful tool for both conservation and coastal management. The coastal area of Porto Pino is represented by sandy shorelines extending for a total length of 5 km characterized by a wide primary and secondary dune systems, a backshore wetland lagoon and marsh area arranged parallel to the coastline. This littoral area can be ideally divided into three parts: the first, about 600 m long, in the north-west part characterized by the highest human pressure due to touristic activity on the foredunes and deposition of beach wrack; the second part in the south-east, about 1100 m long, characterized by a complex dune system (primary and secondary foredunes); and the third southernmost part included in a military area, about 3300 m long, characterized by transgressive dune system with low human

  5. Variation of the Beach Profile, Ocean Beach, San Francisco, California

    NASA Astrophysics Data System (ADS)

    Hansen, J. E.; Ho, T.; Li, A.; Perez, A.; Wong, Y.; Bissell, M.

    2006-12-01

    Ocean Beach is a 7-km-long stretch of beach that is the western boundary of the city of San Francisco with the Pacific Ocean. This beach is exposed to large winter waves produced in the North Pacific and smaller summer waves from both the North and South Pacific. Recent decades have seen an increased rate of erosion at the south end of the beach that has led to the partial collapse of a parking lot, and continued erosion threatens both public and private infrastructure. To gain an understanding of the variation in beach profiles we established six cross-shore profiles approximately 1 km apart. Each profile represents a part of the beach that experiences different wave conditions, caused by refraction across the San Francisco Bar, and thus has a different morphologic response to offshore sea conditions. The six sub-aerial profiles were measured using a total station one week apart in August 2006. All profiles increased in elevation and five of the six profiles showed the early formation or continued growth of berms. The same profiles will be re-analyzed in the autumn to determine further change, and compared to data collected by a 2004 SF-ROCKS group that also studied Ocean Beach. We will relate beach profile change to wave conditions measured at an offshore buoy to determine what wave conditions cause profile accretion or erosion. The results of this study will shed light on the processes occurring at Ocean Beach and will help us to understand why the south end of the beach is eroding.

  6. Post-storm evolution a high-energy remote sandy beach backed by a high and wide coastal dune

    NASA Astrophysics Data System (ADS)

    Castelle, Bruno; Bujan, Stéphane; Ferreira, Sophie

    2016-04-01

    During the winter 2013/2014, the high-energy meso-macrotidal remote beach of Truc Vert (SW France) was exposed to the most energetic wave conditions over at least the last 65 years with, for instance, the 2-month averaged significant wave height at the coast exceeding 3.6 m. Unprecedented beach and dune erosion was observed with the notable presence of a 700-m long localized megacusp embayment with the erosion scarp height exceeding 6 m in its centre where the dune retreat reached 30 m. Both the beach and the coastal dune eroded by about 90 m3/m within 3 months of severe storm activity, that is, a total beach-dune system sediment loss reaching 180m3/m. Beach and dune evolution after the winter 2013/2014 was inspected from March 2014 to November 2015 using bimonthly topographic surveys covering 1500+ m alongshore. 1.5 years after the winter 2014/2015, the beach-dune system did not fully recover to its pre-winter 2014/2015 level. The dune accreted by only a few m3/m while the beach accreted by an impressive amount of approximately 150m3/m, to reach a total volume that was only exceeded in 2012 within our full 10-year time series. Despite little volumetric changes, the dune showed significant morphological change through slumping and onshore wave- and wind-driven sediment transport. Seasonal natural revegetation was observed with large dune grass growth into the summer berm and within the erosion scarp with slumped clots of dune grass re-establishing their growth during the winter 2014/2015. In late 2015, the onset of morphological foredune development was observed. It is anticipated that, if Truc Vert is not exposed to a cluster of severe storms during the winter 2015/2016, the coastal dune will increase in volume within 2016 at a much higher rate than during 2015. Last but not least, starting in late 2015, the coastal dune of Truc Vert is now intensively monitored through regular 4-km long UAV photogrammetric surveys. Given that, nowadays, some scientists advocate

  7. Metopic ridge

    MedlinePlus

    ... infant is made up of bony plates. The gaps between the plates allow for growth of the skull. The places where these plates connect are called sutures or suture lines. They do not fully close until the 2nd or 3rd year of life. A metopic ridge occurs when the ...

  8. HIGH-ANGLE AEOLIAN CROSSBEDDING AT TRAIL RIDGE, FLORIDA.

    USGS Publications Warehouse

    Force, Eric; Garnar, Tom

    1985-01-01

    This paper described new evidence concerning the origin of the Trail Ridge mineral sands deposit in Florida. Rarely exposed sections of the orebody exhibit structures indicative of sand dune formation rather than coastal beach sand accumulation. The implications for mineral sands exploration, and therefore resources, in the southeastern USA are highlighted.

  9. Production of Excirolana armata (Dana, 1853) (Isopoda, Cirolanidae) on an exposed sandy beach in southeastern Brazil

    NASA Astrophysics Data System (ADS)

    Petracco, Marcelo; Cardoso, Ricardo Silva; Turra, Alexander; Corbisier, Thais Navajas

    2012-09-01

    The somatic and gonad productions of the cirolanid isopod Excirolana armata were analyzed by taking monthly samples from December 2003 to November 2005 on Una beach, São Paulo state (24°S), southeastern Brazil. Sampling was performed along three fixed transects established from the base of the foredunes to the waterline. Weight-specific growth rate was used to estimate the E. armata somatic production for 2004 and 2005, separately. The gonad production was estimated based on the monthly reproductive potential (mean number of eggs/embryos per female × monthly abundance of ovigerous females with near-release broods) for 2004. The annual somatic production of E. armata population varied from 15.57 to 17.25 g AFDW m-1 year-1 and the somatic production/biomass ratio ( P s/ B) from 3.55 to 3.14 year-1 for 2004 and 2005, respectively. The P s/ B ratios were higher for males (4.02 and 3.19 year-1 for 2004 and 2005) than for females (3.10 year-1 for both years). The annual gonad production ( P g = 1.07 g AFDW m-1 year-1) contributed about 15 and 6% to the total production ( P s + P g) of females and the population, respectively. The proportion of gonad to somatic production of females ( P g/ P s) increased with individual size (ca 90% in the 7.5 mm size class), and the annual weight-specific gonad production ( P g/ B ratio) was estimated to 0.24 year-1. The high P s/ B ratios estimated for E. armata derive from the fast growth of individuals and show the importance of this population to the energy flow on Una beach ecosystem. However, the low percentage of juveniles verified in this population and in other studies of populations of the genus Excirolana is discussed as an important source of underestimation of P s/ B ratio.

  10. Beach Volume Change Using Uav Photogrammetry Songjung Beach, Korea

    NASA Astrophysics Data System (ADS)

    Yoo, C. I.; Oh, T. S.

    2016-06-01

    Natural beach is controlled by many factors related to wave and tidal forces, wind, sediment, and initial topography. For this reason, if numerous topographic data of beach is accurately collected, coastal erosion/acceleration is able to be assessed and clarified. Generally, however, many studies on coastal erosion have limitation to analyse the whole beach, carried out of partial area as like shoreline (horizontal 2D) and beach profile (vertical 2D) on account of limitation of numerical simulation. This is an important application for prevention of coastal erosion, and UAV photogrammetry is also used to 3D topographic data. This paper analyses the use of unmanned aerial vehicles (UAV) to 3D map and beach volume change. UAV (Quadcopter) equipped with a non-metric camera was used to acquire images in Songjung beach which is located south-east Korea peninsula. The dynamics of beach topography, its geometric properties and estimates of eroded and deposited sand volumes were determined by combining elevation data with quarterly RTK-VRS measurements. To explore the new possibilities for assessment of coastal change we have developed a methodology for 3D analysis of coastal topography evolution based on existing high resolution elevation data combined with low coast, UAV and on-ground RTK-VRS surveys. DSMs were obtained by stereo-matching using Agisoft Photoscan. Using GCPs the vertical accuracy of the DSMs was found to be 10 cm or better. The resulting datasets were integrated in a local coordinates and the method proved to be a very useful fool for the detection of areas where coastal erosion occurs and for the quantification of beach change. The value of such analysis is illustrated by applications to coastal of South Korea sites that face significant management challenges.

  11. Human Health at the Beach

    MedlinePlus

    ... near the site where polluted discharges enter the water. Pollution can also come from high concentrations of farm ... is available online. Other Beach Safety Topics Beyond water pollution, there are other potential threats to human health ...

  12. Polar Ridges

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Context image for PIA03662 Polar Ridges

    This ridge system is located in the south polar region.

    Image information: VIS instrument. Latitude -81.7N, Longitude 296.5E. 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  13. Popham Beach, Maine: An example of engineering activity that saved beach property without harming the beach

    NASA Astrophysics Data System (ADS)

    Kelley, Joseph T.

    2013-10-01

    Beach and property erosion on coasts is a widespread and chronic problem. Historical approaches to this issue, including seawalls and sand replenishment, are often inappropriate or too expensive. In Maine, seawalls were banned in 1983 and replenishment is too costly to employ. Replacement of storm-damaged buildings is also not allowed, and a precedent case on Popham Beach, Maine required that the owner remove an unpermitted building from a site where an earlier structure was damaged. When the most popular park in Maine, Popham Beach State Park, experienced inlet associated erosion that threatened park infrastructure (a bathhouse), temporary measures were all that the law allowed. Because it was clear that the inlet channel causing the erosion would eventually change course, the state opted to erect a temporary seawall with fallen trees at the site. This may or may not have slowed the erosion temporarily, but reassured the public that "something was being done". Once a storm cut a new tidal inlet channel and closed off the old one, tidal water still entered the former channel and continued to threaten the bathhouse. To ultimately save the property, beach scraping was employed. Sand was scraped from the lower beach to construct a sand berm that deflected the tidal current away from the endangered property. This action created enough time for natural processes to drive the remains of the former spit onto the beach and widen it significantly. Whereas many examples of engineering practices exist that endanger instead of saving beaches, this example is one of an appropriate engineering effort to rescue unwisely located beach-front property.

  14. Landing Techniques in Beach Volleyball

    PubMed Central

    Tilp, Markus; Rindler, Michael

    2013-01-01

    The aims of the present study were to establish a detailed and representative record of landing techniques (two-, left-, and right-footed landings) in professional beach volleyball and compare the data with those of indoor volleyball. Beach volleyball data was retrieved from videos taken at FIVB World Tour tournaments. Landing techniques were compared in the different beach and indoor volleyball skills serve, set, attack, and block with regard to sex, playing technique, and court position. Significant differences were observed between men and women in landings following block actions (χ2(2) = 18.19, p < 0.01) but not following serve, set, and attack actions. Following blocking, men landed more often on one foot than women. Further differences in landings following serve and attack with regard to playing technique and position were mainly observed in men. The comparison with landing techniques in indoor volleyball revealed overall differences both in men (χ2(2) = 161.4, p < 0.01) and women (χ2(2) = 84.91, p < 0.01). Beach volleyball players land more often on both feet than indoor volleyball players. Besides the softer surface in beach volleyball, and therefore resulting lower loads, these results might be another reason for fewer injuries and overuse conditions compared to indoor volleyball. Key Points About 1/3 of all jumping actions in beach volleyball result in a landing on one foot. Especially following block situations men land on one foot more often than women. Landing techniques are related to different techniques and positions. Landings on one foot are less common in beach volleyball than indoor volleyball. This could be a reason for fewer injuries and overuse conditions. PMID:24149150

  15. Landing techniques in beach volleyball.

    PubMed

    Tilp, Markus; Rindler, Michael

    2013-01-01

    The aims of the present study were to establish a detailed and representative record of landing techniques (two-, left-, and right-footed landings) in professional beach volleyball and compare the data with those of indoor volleyball. Beach volleyball data was retrieved from videos taken at FIVB World Tour tournaments. Landing techniques were compared in the different beach and indoor volleyball skills serve, set, attack, and block with regard to sex, playing technique, and court position. Significant differences were observed between men and women in landings following block actions (χ(2)(2) = 18.19, p < 0.01) but not following serve, set, and attack actions. Following blocking, men landed more often on one foot than women. Further differences in landings following serve and attack with regard to playing technique and position were mainly observed in men. The comparison with landing techniques in indoor volleyball revealed overall differences both in men (χ(2)(2) = 161.4, p < 0.01) and women (χ(2)(2) = 84.91, p < 0.01). Beach volleyball players land more often on both feet than indoor volleyball players. Besides the softer surface in beach volleyball, and therefore resulting lower loads, these results might be another reason for fewer injuries and overuse conditions compared to indoor volleyball. Key PointsAbout 1/3 of all jumping actions in beach volleyball result in a landing on one foot.Especially following block situations men land on one foot more often than women.Landing techniques are related to different techniques and positions.Landings on one foot are less common in beach volleyball than indoor volleyball. This could be a reason for fewer injuries and overuse conditions. PMID:24149150

  16. 33 CFR 100.736 - Annual Fort Myers Beach air show; Fort Myers Beach, FL.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Annual Fort Myers Beach air show; Fort Myers Beach, FL. 100.736 Section 100.736 Navigation and Navigable Waters COAST GUARD, DEPARTMENT... Fort Myers Beach air show; Fort Myers Beach, FL. (a)(1) Regulated Area. The regulated area is formed...

  17. 33 CFR 100.736 - Annual Fort Myers Beach air show; Fort Myers Beach, FL.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Annual Fort Myers Beach air show; Fort Myers Beach, FL. 100.736 Section 100.736 Navigation and Navigable Waters COAST GUARD, DEPARTMENT... Fort Myers Beach air show; Fort Myers Beach, FL. (a)(1) Regulated Area. The regulated area is formed...

  18. 33 CFR 100.736 - Annual Fort Myers Beach air show; Fort Myers Beach, FL.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Annual Fort Myers Beach air show; Fort Myers Beach, FL. 100.736 Section 100.736 Navigation and Navigable Waters COAST GUARD, DEPARTMENT... Fort Myers Beach air show; Fort Myers Beach, FL. (a)(1) Regulated Area. The regulated area is formed...

  19. 33 CFR 100.736 - Annual Fort Myers Beach air show; Fort Myers Beach, FL.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Annual Fort Myers Beach air show; Fort Myers Beach, FL. 100.736 Section 100.736 Navigation and Navigable Waters COAST GUARD, DEPARTMENT... Fort Myers Beach air show; Fort Myers Beach, FL. (a)(1) Regulated Area. The regulated area is formed...

  20. 33 CFR 100.736 - Annual Fort Myers Beach air show; Fort Myers Beach, FL.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Annual Fort Myers Beach air show; Fort Myers Beach, FL. 100.736 Section 100.736 Navigation and Navigable Waters COAST GUARD, DEPARTMENT... Fort Myers Beach air show; Fort Myers Beach, FL. (a)(1) Regulated Area. The regulated area is formed...

  1. 76 FR 37700 - Safety Zone; Myrtle Beach Triathlon, Atlantic Intracoastal Waterway, Myrtle Beach, SC

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-28

    ... notice regarding our public dockets in the January 17, 2008, issue of the Federal Register (73 FR 3316... Intracoastal Waterway, Myrtle Beach, SC AGENCY: Coast Guard, DHS. ACTION: Notice of proposed rulemaking... Waterway in Myrtle Beach, South Carolina during the Myrtle Beach Triathlon. The Myrtle Beach...

  2. 77 FR 14321 - Safety Zone; Myrtle Beach Triathlon, Atlantic Intracoastal Waterway, Myrtle Beach, SC

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-09

    ..., 2008, issue of the Federal Register (73 FR 3316). Public Meeting We do not now plan to hold a public... Intracoastal Waterway, Myrtle Beach, SC AGENCY: Coast Guard, DHS. ACTION: Notice of proposed rulemaking... Waterway in Myrtle Beach, South Carolina during the Myrtle Beach Triathlon. The Myrtle Beach...

  3. Geomorphology of coastal sand dunes, Baldwin County, Alabama

    USGS Publications Warehouse

    Bearden, Bennett L.; Hummell, Richard L.; Mink, Robert M.

    1989-01-01

    Alabama's coastal eolian deposits are primarily vegetated dunes that are exemplified by sand ridges with flat to undulating upper surfaces and continuous irregular crests. Dune fields occur along Morgan peninsula between the foredune line and Little Lagoon and the Mobile Bay area. These dune fields consist primarily of one or more continuous ridges that parallel the coast and are generally vegetaed to grassy. Washover of the beach and backshore during Hurricane Frederic (1979) and subsequent smaller scale storms resulted in significant erosion of many of Alabama's dune fields. The primary dunes or foredunes are beginning to recover from the effects of these storms; however, numerous breaks in the primary dune line are present. Sand dunes in coastal Alabama provide protection against storm-generated waves and washover. The foredunes are protected by adherence to a Coastal Construction Control Line (CCCL) or construction setback line identified by markers along coastal Baldwin County.

  4. 75 FR 24997 - FPL Energy Point Beach, LLC; Point Beach Nuclear Plant, Units 1 and 2; Environmental Assessment...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-06

    ... COMMISSION FPL Energy Point Beach, LLC; Point Beach Nuclear Plant, Units 1 and 2; Environmental Assessment... Energy Point Beach, LLC (the licensee), for operation of the Point Beach Nuclear Plant, Units 1 and 2... Licensee and Owner from ``FPL Energy Point Beach, LLC'' to ``NextEra Energy Point Beach, LLC.''...

  5. Differentiating Experts' Anticipatory Skills in Beach Volleyball

    ERIC Educational Resources Information Center

    Canal-Bruland, Rouwen; Mooren, Merel; Savelsbergh, Geert J. P.

    2011-01-01

    In this study, we examined how perceptual-motor expertise and watching experience contribute to anticipating the outcome of opponents' attacking actions in beach volleyball. To this end, we invited 8 expert beach volleyball players, 8 expert coaches, 8 expert referees, and 8 control participants with no beach volleyball experience to watch videos…

  6. Beach lamination: Nature and origin

    USGS Publications Warehouse

    Clifton, H.E.

    1969-01-01

    A distinctive two-fold sedimentation unit characterizes lamination in the upper swash zone of beaches. Within the unit a fine and/or a heavy mineral rich layer at the base grades upward into a coarser and/or a heavy mineral poor layer at the top. This distinctive type of lamination results from grain segregation within bed flow during wave backwash. ?? 1969.

  7. Inside the "Long Beach Way"

    ERIC Educational Resources Information Center

    Olson, Lynn

    2007-01-01

    This article features Long Beach Unified School District, the 2003 winner of a prestigious prize in urban education. The district of more than 90,000 students is the first winner of the award to return to the competition as a finalist. Its reappearance on the list after earning the prize in 2003 raises interesting questions about how districts…

  8. Virtual Beach 3: user's guide

    USGS Publications Warehouse

    Cyterski, Mike; Brooks, Wesley; Galvin, Mike; Wolfe, Kurt; Carvin, Rebecca; Roddick, Tonia; Fienen, Mike; Corsi, Steve

    2014-01-01

    Virtual Beach version 3 (VB3) is a decision support tool that constructs site-specific statistical models to predict fecal indicator bacteria (FIB) concentrations at recreational beaches. VB3 is primarily designed for beach managers responsible for making decisions regarding beach closures or the issuance of swimming advisories due to pathogen contamination. However, researchers, scientists, engineers, and students interested in studying relationships between water quality indicators and ambient environmental conditions will find VB3 useful. VB3 reads input data from a text file or Excel document, assists the user in preparing the data for analysis, enables automated model selection using a wide array of possible model evaluation criteria, and provides predictions using a chosen model parameterized with new data. With an integrated mapping component to determine the geographic orientation of the beach, the software can automatically decompose wind/current/wave speed and magnitude information into along-shore and onshore/offshore components for use in subsequent analyses. Data can be examined using simple scatter plots to evaluate relationships between the response and independent variables (IVs). VB3 can produce interaction terms between the primary IVs, and it can also test an array of transformations to maximize the linearity of the relationship The software includes search routines for finding the "best" models from an array of possible choices. Automated censoring of statistical models with highly correlated IVs occurs during the selection process. Models can be constructed either using previously collected data or forecasted environmental information. VB3 has residual diagnostics for regression models, including automated outlier identification and removal using DFFITs or Cook's Distances.

  9. Sequential monitoring of beach litter using webcams.

    PubMed

    Kako, Shin'ichiro; Isobe, Atsuhiko; Magome, Shinya

    2010-05-01

    This study attempts to establish a system for the sequential monitoring of beach litter using webcams placed at the Ookushi beach, Goto Islands, Japan, to establish the temporal variability in the quantities of beach litter every 90 min over a one and a half year period. The time series of the quantities of beach litter, computed by counting pixels with a greater lightness than a threshold value in photographs, shows that litter does not increase monotonically on the beach, but fluctuates mainly on a monthly time scale or less. To investigate what factors influence this variability, the time derivative of the quantity of beach litter is compared with satellite-derived wind speeds. It is found that the beach litter quantities vary largely with winds, but there may be other influencing factors. PMID:20392465

  10. Recharge into a shingle beach

    NASA Astrophysics Data System (ADS)

    Keating, T.

    1984-04-01

    Traditionally, groundwater recharge in the U.K. has been calculated by the Penman method on a monthly basis, using values of potential evaporation derived from averaged meteorological data and monthly totals of rainfall. Recent work by K.W.F. Howard and J.W. Lloyd has shown that these monthly totals considerably underestimate recharge calculated over shorter time periods and they suggested that 1-day, or at worst, 10-day intervals should be used. In this paper field experiments to measure recharge into a shingle beach are reported. These experiments were made with a lysimeter over a 6-yr. period and have shown that recharge into the shingle occurs whenever significant precipitation occurs, even during the summer months. The Penman model is shown to be unrealistic for estimating recharge into such a beach and an alternative model for calculating recharge is proposed. This model is shown to yield good results.

  11. Grafts for Ridge Preservation

    PubMed Central

    Jamjoom, Amal; Cohen, Robert E.

    2015-01-01

    Alveolar ridge bone resorption is a biologic phenomenon that occurs following tooth extraction and cannot be prevented. This paper reviews the vertical and horizontal ridge dimensional changes that are associated with tooth extraction. It also provides an overview of the advantages of ridge preservation as well as grafting materials. A Medline search among English language papers was performed in March 2015 using alveolar ridge preservation, ridge augmentation, and various graft types as search terms. Additional papers were considered following the preliminary review of the initial search that were relevant to alveolar ridge preservation. The literature suggests that ridge preservation methods and augmentation techniques are available to minimize and restore available bone. Numerous grafting materials, such as autografts, allografts, xenografts, and alloplasts, currently are used for ridge preservation. Other materials, such as growth factors, also can be used to enhance biologic outcome. PMID:26262646

  12. Supratidal beach deposits in Giralia Bay (Exmouth Gulf, Western Australia) - a record for past tropical cyclones?

    NASA Astrophysics Data System (ADS)

    May, Simon Matthias; Gelhausen, Henrik; Brill, Dominik; Callow, Nik; Engel, Max; Scheffers, Anja; Joannes-Boyau, Renaud; Leopold, Matthias; Opitz, Stephan; Brückner, Helmut

    2016-04-01

    Past coastal flooding events related to tropical cyclones (TCs) and tsunamis may be inferred from geomorphic and sedimentary archives, i.e. in the form of particular landforms (beach ridges, washover fans), deposits (washover sediments in lagoons) or erosional features. In Giralia Bay, southern Exmouth Gulf (Western Australia), sandy ridge sequences in supratidal elevations form the landward margin of extensive mudflats. The formation of these ridges, as in other mudflats of NW Australia, is assumed to be mainly driven by TCs, although their relation to depositional processes and inundation levels during spring tide conditions, exceptional precipitation and discharge events, and storm surges needs to be clarified. Based on a simple process monitoring setup using a time-lapse camera and pressure gauges, geomorphological mapping by means of unmanned aerial vehicle survey and structure-from-motion techniques, as well as sedimentological and geochronological investigations, this study aims at (i) establishing the chronostratigraphy and reconstructing the formation of the supratidal beach deposits; (ii) identifying the most important driving processes involved in their formation; and (iii) understanding their significance for recording past TC activity. Sediment trenches cross the youngest, most seaward part of the ridge sequence. At the base of the sedimentary succession, sandy units are interbedded with mud layers, reflecting depositional conditions similar to the present distal mudflat. In the upper part of the ridges, mud intercalations recede, and sand layers of varying grain size distribution and mineralogical content dominate. Younger sediment layers clearly attach to older ones documenting the stepwise accretion of the ridges onto the mudflat. Muddy intercalations in the upper part of the succession are interpreted to represent deposition in locally restricted swales. Monitoring covered the time period between August 2013 and 2015 and capture an exceptional

  13. Contact with beach sand among beach-goers and risk of illness

    EPA Science Inventory

    Background: Recently, numerous studies of fecal contamination of beach sand have triggered interest among scientists, the news media, and the general public. Evidence shows that beach sand harbors higher concentrations of fecal indicator organisms (microbes considered to indicate...

  14. Beach monitoring criteria: reading the fine print

    USGS Publications Warehouse

    Nevers, Meredith B.; Whitman, Richard L.

    2011-01-01

    Beach monitoring programs aim to decrease swimming-related illnesses resulting from exposure to harmful microbes in recreational waters, while providing maximum beach access. Managers are advised by the U.S. EPA to estimate microbiological water quality based on a 5-day geometric mean of fecal indicator bacteria (FIB) concentrations or on a jurisdiction-specific single-sample maximum; however, most opt instead to apply a default single-sample maximum to ease application. We examined whether re-evaluation of the U.S. EPA ambient water quality criteria (AWQC) and the epidemiological studies on which they are based could increase public beach access without affecting presumed health risk. Single-sample maxima were calculated using historic monitoring data for 50 beaches along coastal Lake Michigan on various temporal and spatial groupings to assess flexibility in the application of the AWQC. No calculation on either scale was as low as the default maximum (235 CFU/100 mL) that managers typically use, indicating that current applications may be more conservative than the outlined AWQC. It was notable that beaches subject to point source FIB contamination had lower variation, highlighting the bias in the standards for these beaches. Until new water quality standards are promulgated, more site-specific application of the AWQC may benefit beach managers by allowing swimmers greater access to beaches. This issue will be an important consideration in addressing the forthcoming beach monitoring standards.

  15. USING HYDROGRAPHIC DATA AND THE EPA VIRTUAL BEACH MODEL TO TEST PREDICTIONS OF BEACH BACTERIA CONCENTRATIONS

    EPA Science Inventory

    A modeling study of 2006 Huntington Beach (Lake Erie) beach bacteria concentrations indicates multi-variable linear regression (MLR) can effectively estimate bacteria concentrations compared to the persistence model. Our use of the Virtual Beach (VB) model affirms that fact. VB i...

  16. NOWCASTING AND FORECASTING BEACH BACTERIA CONCENTRATIONS USING EPA VIRTUAL BEACH SOFTWARE

    EPA Science Inventory

    Evidence shows that traditional persistence-based beach closure decision making is inadequate, beaches are closed when they could be open and kept open when they should be closed. Intense interest is now focused on efforts to nowcast beach conditions using surrogate variables, su...

  17. 77 FR 27120 - Safety Zone; Virginia Beach Oceanfront Air Show, Atlantic Ocean, Virginia Beach, VA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-09

    ..., Virginia Beach, VA in the Federal Register (76 FR 13519). We received one comment on the proposed rule. No... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Virginia Beach Oceanfront Air Show, Atlantic Ocean, Virginia Beach, VA AGENCY: Coast Guard, DHS. ACTION: Temporary final rule. SUMMARY:...

  18. VISUAL BEACH: SOFTWARE FOR ACHIEVING BEACH AESTHETIC AND PUBLIC HEALTH PROTECTION

    EPA Science Inventory

    The Beaches Environmental Assessment and Coastal Health Act of 2000 directs the EPA to assure that 100% of significant public beaches are managed by 2008. Under the Act EPA is developing a program to monitor beach water quality and strategies for timely notification of the public...

  19. 130. PLAN OF IMPROVEMENT, HUNTINGTON BEACH MUNICIPAL PIER: LIGHTING DETAILS. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    130. PLAN OF IMPROVEMENT, HUNTINGTON BEACH MUNICIPAL PIER: LIGHTING DETAILS. Sheet 11 of 11 (#3284) - Huntington Beach Municipal Pier, Pacific Coast Highway at Main Street, Huntington Beach, Orange County, CA

  20. 129. PLAN OF IMPROVEMENT, HUNTINGTON BEACH MUNICIPAL PIER: LIGHTING DIAGRAM. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    129. PLAN OF IMPROVEMENT, HUNTINGTON BEACH MUNICIPAL PIER: LIGHTING DIAGRAM. Sheet lO of 11 (#3283) - Huntington Beach Municipal Pier, Pacific Coast Highway at Main Street, Huntington Beach, Orange County, CA

  1. 124. PLAN OF IMPROVEMENT, HUNTINGTON BEACH MUNICIPAL PIER: RAMP DETAILS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    124. PLAN OF IMPROVEMENT, HUNTINGTON BEACH MUNICIPAL PIER: RAMP DETAILS Sheet 6 of 11 (#3278) - Huntington Beach Municipal Pier, Pacific Coast Highway at Main Street, Huntington Beach, Orange County, CA

  2. 120. PLAN OF IMPROVEMENT, HUNTINGTON BEACH MUNICIPAL PIER: LAYOUT OF ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    120. PLAN OF IMPROVEMENT, HUNTINGTON BEACH MUNICIPAL PIER: LAYOUT OF EXISTING PIER Sheet 2 of 11 (#3274) - Huntington Beach Municipal Pier, Pacific Coast Highway at Main Street, Huntington Beach, Orange County, CA

  3. 7. GROUND VIEW OF PIER, LOOKING EAST FROM BEACH; SHOWING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. GROUND VIEW OF PIER, LOOKING EAST FROM BEACH; SHOWING 27TH BENT LANDWARD TO MAXWELL'S RESTAURANT, NEPTUNE'S GALLEY (RIGHT OF CENTER) - Huntington Beach Municipal Pier, Pacific Coast Highway at Main Street, Huntington Beach, Orange County, CA

  4. 8. GROUND VIEW OF PIER, LOOKING SOUTH FROM BEACH; SHOWING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. GROUND VIEW OF PIER, LOOKING SOUTH FROM BEACH; SHOWING 17TH BENT TO END; NEPTUNE'S GALLEY TO END OF PIER - Huntington Beach Municipal Pier, Pacific Coast Highway at Main Street, Huntington Beach, Orange County, CA

  5. 126. PLAN OF IMPROVEMENT, HUNTINGTON BEACH MUNICIPAL PIER: EXTENSION DETAILS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    126. PLAN OF IMPROVEMENT, HUNTINGTON BEACH MUNICIPAL PIER: EXTENSION DETAILS Sheet 7 of 11 (#3280) - Huntington Beach Municipal Pier, Pacific Coast Highway at Main Street, Huntington Beach, Orange County, CA

  6. 45. VIEW OF STAIRWAY UP FROM BEACH TO PIER APPROACH, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    45. VIEW OF STAIRWAY UP FROM BEACH TO PIER APPROACH, NORTHWEST SIDE OF PIER, LOOKING NORTHEAST - Huntington Beach Municipal Pier, Pacific Coast Highway at Main Street, Huntington Beach, Orange County, CA

  7. 127. PLAN OF IMPROVEMENT, HUNTINGTON BEACH MUNICIPAL PIER: FRAMING DETAILS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    127. PLAN OF IMPROVEMENT, HUNTINGTON BEACH MUNICIPAL PIER: FRAMING DETAILS Sheet 8 of 11 (#3281) - Huntington Beach Municipal Pier, Pacific Coast Highway at Main Street, Huntington Beach, Orange County, CA

  8. 121. PLAN OF IMPROVEMENT, HUNTINGTON BEACH MUNICIPAL PIER: LAYOUT OF ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    121. PLAN OF IMPROVEMENT, HUNTINGTON BEACH MUNICIPAL PIER: LAYOUT OF EXISTING PIER Sheet 3 of 11 (#3275) - Huntington Beach Municipal Pier, Pacific Coast Highway at Main Street, Huntington Beach, Orange County, CA

  9. 10. GROUND VIEW OF PIER, LOOKING SOUTH FROM BEACH; SHOWING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. GROUND VIEW OF PIER, LOOKING SOUTH FROM BEACH; SHOWING (LEFT-RIGHT) CAPTAIN'S GALLEY'S GALLEY TO END OF PIER - Huntington Beach Municipal Pier, Pacific Coast Highway at Main Street, Huntington Beach, Orange County, CA

  10. 122. PLAN OF IMPROVEMENT, HUNTINGTON BEACH MUNICIPAL PIER: LAYOUT OF ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    122. PLAN OF IMPROVEMENT, HUNTINGTON BEACH MUNICIPAL PIER: LAYOUT OF EXTENSION TO PIER Sheet 4 of 11 (#3276) - Huntington Beach Municipal Pier, Pacific Coast Highway at Main Street, Huntington Beach, Orange County, CA

  11. 125. PLAN OF IMPROVEMENT, HUNTINGTON BEACH MUNICIPAL PIER: MODIFIED RAMP ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    125. PLAN OF IMPROVEMENT, HUNTINGTON BEACH MUNICIPAL PIER: MODIFIED RAMP DETAILS Sheet 6A of 11 (#3279) - Huntington Beach Municipal Pier, Pacific Coast Highway at Main Street, Huntington Beach, Orange County, CA

  12. 110. PLAN AND ELEVATION OF HUNTINGTON BEACH MUNICIPAL PIER: PIER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    110. PLAN AND ELEVATION OF HUNTINGTON BEACH MUNICIPAL PIER: PIER APPROACH TO MID-SECTION Sheet 1 of 9 (#3252) - Huntington Beach Municipal Pier, Pacific Coast Highway at Main Street, Huntington Beach, Orange County, CA

  13. 128. PLAN OF IMPROVEMENT, HUNTINGTON BEACH MUNICIPAL PIER: BOAT LANDING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    128. PLAN OF IMPROVEMENT, HUNTINGTON BEACH MUNICIPAL PIER: BOAT LANDING DETAILS Sheet 9 of 11 (#3282) - Huntington Beach Municipal Pier, Pacific Coast Highway at Main Street, Huntington Beach, Orange County, CA

  14. BEACH ROAD SHOWING THE LAWN WITH KIAWE TREES BETWEEN THE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    BEACH ROAD SHOWING THE LAWN WITH KIAWE TREES BETWEEN THE ROAD AND THE BEACH. BEACH ROAD IS 14' WIDE. VIEW FACING SOUTH. - Hickam Field, Fort Kamehameha Historic Housing, Along Worchester Avenue & Hope Street, Honolulu, Honolulu County, HI

  15. 104. VIEW OF NORTHWEST SIDE OF PIER TAKEN FROM BEACH, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    104. VIEW OF NORTHWEST SIDE OF PIER TAKEN FROM BEACH, LOOKING SOUTH. BANDSHELL IS AT RIGHT Photograph #1574-HB. Photographer unknown, c. 1914 - Huntington Beach Municipal Pier, Pacific Coast Highway at Main Street, Huntington Beach, Orange County, CA

  16. 123. PLAN OF IMPROVEMENT, HUNTINGTON BEACH MUNICIPAL PIER: REPAIR DETAILS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    123. PLAN OF IMPROVEMENT, HUNTINGTON BEACH MUNICIPAL PIER: REPAIR DETAILS Sheet 5 of 11 (#3277) - Huntington Beach Municipal Pier, Pacific Coast Highway at Main Street, Huntington Beach, Orange County, CA

  17. 111. PLAN AND ELEVATION OF HUNTINGTON BEACH MUNICIPAL PIER: PIER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    111. PLAN AND ELEVATION OF HUNTINGTON BEACH MUNICIPAL PIER: PIER MID-SECTION TO END Sheet 2 of 9 (#3253) - Huntington Beach Municipal Pier, Pacific Coast Highway at Main Street, Huntington Beach, Orange County, CA

  18. Storm-built sand ridges on the Maryland inner shelf: a preliminary report

    USGS Publications Warehouse

    Swift, D.J.P.; Field, M.E.

    1981-01-01

    Several aspects of the Maryland ridge field are pertinent to the problem of ridge genesis in response to Holocene sea-level rise. There is a systematic morphologic change from shoreface ridges through nearshore ridges to offshore ridges, which reflects the changing hydraulic regime. Grain size is 90?? out of phase with topography, so that the coarsest sand lies between the axis of each trough and the adjacent seaward ridge crest, while the finest sand lies between each ridge crest and the axis of the adjacent seaward trough. Finally, analysis over a 43-year period on an outer ridge reveals a systematic pattern of landward flank erosion, seaward flank deposition, and seaward crest migration. These relationships support a model which explains the ridges as consequences of the up-current shift of maximum bottom shear stress with respect to the crests of initial bottom irregularities. The oblique orientation of the ridges with respect to the beach may be at least partly due to the more rapid migration rate of the ridges' inshore ends. ?? 1981 A.M. Dowden, Inc.

  19. Long Beach's Pivotal Turn around RTI

    ERIC Educational Resources Information Center

    Elliott, Judy

    2008-01-01

    This article briefly describes the tiered approach to intervention adopted by the Long Beach Unified School District. Long Beach Unified School District is the state's third largest urban school district with more than 90,000 students, 84 percent of whom are minority and 68 percent of whom qualify for free and reduced price lunch, and where over…

  20. A Study of Sandy Beach Zonation.

    ERIC Educational Resources Information Center

    Alexander, Steve K.

    1991-01-01

    Describes the study of sandy beach zonations as a seashore activity for either high school or lower-level college courses in biology, ecology, or marine biology. Students first draw a profile of a beach scene and then collect specimens from the zones of the shore. In a laboratory, students identify their specimens and relate them to the beach…

  1. PREDICTING BACTERIAL CONCENTRATION ON THE NATION'S BEACHES

    EPA Science Inventory

    A classical example of the failure of institutions and environmental technology to protect the nation's aesthetic, recreational, and public health values is represented by the July-August, 1999 Huntington Beach, California beach closure. This multi-million dollar regional public ...

  2. Effects of beach cast cleaning on beach quality, microbial food web, and littoral macrofaunal biodiversity

    NASA Astrophysics Data System (ADS)

    Malm, Torleif; Råberg, Sonja; Fell, Sabine; Carlsson, Per

    2004-06-01

    At the end of the summer, drifting filamentous red algae cover shallow bottoms and accumulate in huge cast walls on the open shores of the non-tidal central Baltic Sea. The hypotheses that beach cleaning increases water clarity, decreases the organic content of the sand, and increases the species diversity in the shallow zone closest to the shore, were tested through field investigations and experiments. Cleaned shorelines were compared with un-cleaned shorelines at two sites with different intensity of beach cleaning in a rural area of SE Sweden. The results show that water clarity was significantly increased off the intensively cleaned beach but not off the moderately cleaned one. Similarly, the total leakage of nitrogenous compounds decreased off the intensively cleaned beach, but not off the moderately cleaned. The organic content of the sand was lower on both cleaned beaches compared with nearby un-cleaned beaches. The total animal biomass was significantly lower on the intensively cleaned beach compared with the un-cleaned beach, but the moderately cleaned beach gave no such effect. The difference in biodiversity and community structure between cleaned and un-cleaned beaches was insignificant. The most obvious difference in species composition was a much higher number of planktivore opossum shrimps of the genus Mysis and Praunus on the un-cleaned beaches. The bacterial production and the amount of ciliates larger than 20 mm were also higher on un-cleaned beaches, indicating that the microbial food web off the un-cleaned beaches is stimulated by the discharge of decomposing algal material. The conclusion of the study is that mechanical cleaning reduces the organic content of the beach sand and may change the water quality and microbial production, but the effect on the macrofaunal biodiversity is insignificant.

  3. Suprabenthic biodiversity of Catalan beaches (NW Mediterranean)

    NASA Astrophysics Data System (ADS)

    Munilla, T.; San Vicente, C.

    2005-03-01

    An analysis of the suprabenthos has been carried out on 13 diverse type beaches in Catalonian coast (NE of Spain). A total of 29 717 specimens, belonging to 145 species and eight different zoological groups (mysids, amphipods, cumaceans, isopods, tanaidaceans, decapods, pycnogonids, and teleostean fishes) were obtained. The suprabenthos of Catalan beaches were characterized by a mean density of 40 ind. m -2, by the abundance of Mysids (75% of the total density) and by the higher diversity of Amphipods (64 species). Five population species were considered as typical of suprabenthic assemblages: Schistomysis assimilis, Mesopodopsis slabberi, Atylus guttatus, Pontocrates altamarinus, and Cumopsis goodsir. Four main types of beaches with different number of suprabenthic species and densities and three main faunistic groups are described and related to environmental physical factors of the analysed beaches (morphodynamics, exposure, etc.). The macrofaunal trend about to that the species richness decrease from dissipative to reflective beaches is confirmed for the suprabenthic communities.

  4. Dynamics of Shengjini beach (Albania)

    NASA Astrophysics Data System (ADS)

    Gashi, Ferim; Nikolli, Pal

    2015-04-01

    Dynamics of Shengjini beach (Albania) Pal Nikolli , Ferim GASHI Through archaeological and historical data, presentations of ancient topographic, cartographic materials (topographic maps obtained at different periods from 1870 to 1990), aerial photographs (2007), satellite images (2014) and direct measurements, paper defines and analyzes the position of the coastline of Shengjini beach (Lezha) from century XVI until today. The coastline of the Shengjini city (port) to Drin River estuary is oriented north-south direction and is approximately 10.5 km long. This part of the coast is sandy and sediment comes mainly from the River Drin and distributed by currents along the coast. In this paper are make provision for the position of the coastline in the future and analyzed the possibilities of human intervention in the coastal environment , etc. This work forms the basis for the issuance of necessary data required for various projections at the coastal environment Shëngjini. Results of this study will have a significant impact on state policies for integrated management of the coastal zone in the study and development of tourism. Key words: GIS, Remonte Sennsing, cartography, management of coastal zone, tourism, environment.

  5. Horseshoe crab (Limulus polyphemus) reproductive activity on Delaware Bay beaches: Interactions with beach characteristics

    USGS Publications Warehouse

    Smith, D.R.; Pooler, P.S.; Loveland, R.E.; Botton, M.L.; Michels, S.F.; Weber, R.G.; Carter, Daniel B.

    2002-01-01

    We used results from a survey of horseshoe crab reproductive activity that was conducted in 1999 throughout Delaware Bay to examine the relationship between estimates of spawning females and egg deposition and analyze how that relationship varies with geography, time within a spawning season, beach morphology, and wave energy. We found that beach morphology and wave energy interacted with density of spawning females to explain variation in the density and distribution of eggs and larvae. For example, the quantity of eggs in surface sediment (i.e., eggs that are potentially available to foraging shorebirds) was associated with the density of spawning females, beach morphology, and wave energy. The association between beach morphology and live eggs in surface sediment was strong especially in late May (Percent Reduction in Error = 86% from regression tree model) where egg density was an order of magnitude higher on beaches <15 m wide (3.38*105 m-2; 90% CI: 2.29*105, 4.47*105) compared to wider beaches (1.49*104 m-2; 90% CI: 4.47*103, 2.53*104). Results also indicate that, among bay-front beaches, horseshoe crabs prefer to spawn on narrow beaches, possibly because of reduced wave energy. At peak periods of spawning activity, density of spawning females was inversely related to foreshore width on mid-latitude beaches within Delaware Bay (t = -2.68, 7 df, p = 0.03). Because the distribution of eggs across the foreshore varied with beach morphology and widened as the spawning season progressed, methods used to sample eggs need to be robust to variation in beach morphology and applicable regardless of when the samples are taken. Because beach morphology and wave energy were associated with the quantity of eggs in surface sediment, certain beach types may be critical to the conservation of shorebird foraging habitat.

  6. A hybrid beach morphology model applied to a high energy sandy beach

    NASA Astrophysics Data System (ADS)

    Karunarathna, Harshinie; Ranasinghe, Roshanka; Reeve, Dominic E.

    2015-11-01

    In this paper, the application of a hybrid coastal morphodynamic model to forecast inter-annual beach change is discussed through the prediction of beach change in a high energy sandy beach over a period of 5 years. The modelling approach combines a `reduced-physics' formulation with a data-driven approach through an inverse technique to form the hybrid coastal morphodynamic model. The beach considered for the demonstration of the model is the Narrabeen Beach, which is a dynamic sand beach located in New South Wales, Australia. Despite its simplicity, we find that the model is able to capture beach change at Narrabeen Beach at inter-annual timescales with root mean square error between measured and computed beach profiles less than 0.4 m on average. Even though the model is used to forecast inter-annual beach change in this study, its ability to predict beach change is not limited to that timescale but depends on the frequency of historic beach profile measurements available to determine key unknown parameters of the model. Also, the length of profile forecasts largely depends on the length of available historic measurements where longer data sets allow longer predictions within a range of beach behaviour contained in the observations. The ability of the model to reliably forecast coastal change at inter-annual and potentially at other timescales, and its high efficiency make it possible to be used in providing multiple simulations required for probabilistic coastal change forecasts which will be very useful for coastal management purposes.

  7. Tar loads on Omani beaches

    SciTech Connect

    Badawy, M.I.; Al-Harthy, F.T. )

    1991-11-01

    Owing to Oman's geographic position and long coastal line, the coastal areas of Oman are particularly vulnerable to oil pollution from normal tanker operations, illegal discharges, and accidental spills as well as local sources of oil input. UNEP carried out a survey on the coasts of Oman to determine the major sources of oil pollution and concluded that the major shoreline pollution problems in Oman arose from operational discharges of oil from passing vessels traffic. The oil, because of the high sea and air temperatures in the area, was subjected to relatively high rates of evaporation and photo-oxidation and tended to arrive at the coast as heavy petroleum particulate residues (tar balls). The aim of the present study was to measure the loads of tar balls in Omani coastal areas and to identify the source of oil pollutants on beaches.

  8. Sheet-gravel evidence for a late Holocene tsunami run-up on beach dunes, Great Barrier Island, New Zealand

    NASA Astrophysics Data System (ADS)

    Nichol, Scott L.; Lian, Olav B.; Carter, Charles H.

    2003-01-01

    A semi-continuous sheet of granule to cobble-size clasts forms a distinctive deposit on sand dunes located on a coastal barrier in Whangapoua Bay, Great Barrier Island, New Zealand. The gravel sheet extends from the toe of the foredune to 14.3 m above mean sea level and 200 m landward from the beach. Clasts are rounded to sub-rounded and comprise lithologies consistent with local bedrock. Terrestrial sources for the gravel are considered highly unlikely due to the isolation of the dunes from hillslopes and streams. The only source for the clasts is the nearshore to inner shelf of Whangapoua Bay, where gravel sediments have been previously documented. The mechanism for transport of the gravel is unlikely to be storm surge due to the elevation of the deposit; maximum-recorded storm surge on this coast is 0.8 m above mean high water spring tide. Aeolian processes are also discounted due to the size of clasts and the elevation at which they occur. Tsunami is therefore considered the most probable mechanism for gravel transport. Minimum run-up height of the tsunami was 14.3 m, based on maximum elevation of gravel deposits. Optical ages on dune sands beneath and covering the gravel allow age bracketing to 0-4.7 ka. Within this time frame, numerous documented regional seismic and volcanic events could have generated the tsunami, notably submarine volcanism along the southern Kermadec arc to the east-southeast of Great Barrier Island where large magnitude events are documented for the late Holocene. Radiocarbon ages on shell from Maori middens that appear to have been reworked by tsunami run-up constrain the age of this event to post ca. 1400 AD. Regardless of the precise age of this event, the well-preserved nature of the Whangapoua gravel deposit provides for an improved understanding of the high degree of spatial variability in tsunami run-up.

  9. 75 FR 16201 - FPL Energy Point Beach, LLC; Point Beach Nuclear Plant, Units 1 and 2; Exemption

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-31

    ... COMMISSION FPL Energy Point Beach, LLC; Point Beach Nuclear Plant, Units 1 and 2; Exemption 1.0 Background FPL Energy Point Beach, LLC (FPLE, the licensee) is the holder of Renewed Facility Operating License Nos. DPR-24 and DPR-27, which authorize operation of the Point Beach Nuclear Plant, Units 1 and...

  10. The Different Faces of San Francisco's Ocean Beach: Analyzing Sand Size and Beach Shape

    NASA Astrophysics Data System (ADS)

    Grove, K.; Labit, R.; Lui, S.; Rodriquez, I.; Yi, C.; Yu, M.

    2004-12-01

    Ocean Beach is located along the western edge of San Francisco adjacent to the Pacific Ocean. Erosion along the southern part of the beach is threatening a nearby highway and water treatment plant. To better understand this beach and the processes that form it, our SF-ROCKS research group collected data from seven locations along its length. We used an auto-level surveying instrument to measure beach profiles and we collected sand samples that were measured using sieves and a sieve shaker. We plotted profiles and grain-size data using Excel and Surfer software. The sediment is mostly fine sand, and the means of all samples range between 0.19-0.26 mm. There may be little variation along the beach because only small sand grains have survived the long journey from their Sierra Nevada source. Profile shape does vary along the beach. The profile at the northern end is about three times wider than the profile at the southern end. The northern profile is flatter overall, but all profiles had a steep beach face in August, when the data were collected. The differences in beach profiles may be related to position relative to the offshore bar, which appears to provide sand to the northern part of the beach. Our group will collect more data in November to see what changes have occurred after the large-wave season has begun. We will use Surfer software to compare summer and fall profiles, to see where sediment has been added and where sediment has been removed. We will also compare our results to the data collected by Dr. Patrick Barnard and his research group at the U.S. Geological Survey, who are using an All-Terrain Vehicle to measure beach profiles and a camera to measure sediment size. We will use our analysis of beach variations to make recommendations for reducing beach erosion.

  11. Morphodynamics of a mesotidal rocky beach: Palmeras beach, Gorgona Island National Natural Park, Colombia

    NASA Astrophysics Data System (ADS)

    Gómez-García, A. M.; Bernal, G. R.; Osorio, A. F.; Botero, V.

    2014-10-01

    The response of a rocky beach to different possible combinations of hydrodynamic conditions (tides, waves, oceanic currents) has been little studied. In this work, the morphodynamic response to different hydrodynamic forcing is evaluated from sedimentological and geomorphological analysis in seasonal and medium term (19 years) scale in Palmeras beach, located in the southwest of Gorgona Island National Natural Park (NNP), a mesotidal rocky island on the Colombian Pacific continental shelf. Palmeras is an important nesting area of two types of marine turtles, with no anthropogenic stress. In the last years, coastal erosion has reduced the beach width, restricting the safe areas for nesting and conservation of these species. Until now, the sinks, sources, reservoirs, rates, and paths of sediments were unknown, as well as their hydrodynamic forcing. The beach seasonal variability, from October 2010 to August 2012, was analyzed based on biweekly or monthly measurements of five beach profiles distributed every 200 m along the 1.2 km of beach length. The main paths for sediment transport were defined from the modeling of wave currents with the SMC model (Coastal Modeling System), as well as the oceanic currents, simulated for the dry and wet seasons of 2011 using the ELCOM model (Estuary and Lake COmputer Model). Extreme morphologic variations over a time span of 19 years were analyzed with the Hsu and Evans beach static equilibrium parabolic model, from one wave diffraction point which dominates the general beach plan shape. The beach lost 672 m3/m during the measuring period, and erosional processes were intensified during the wet season. The beach trends responded directly to a wave mean energy flux change, resulting in an increase of up to 14 m in the width northward and loss of sediments in the beach southward. This study showed that to obtain the integral morphodynamic behavior of a rocky beach it is necessary to combine information of hydrodynamic, sedimentology

  12. Effects of beach replenishment on intertidal invertebrates: A 15-month, eight beach study.

    NASA Astrophysics Data System (ADS)

    Wooldridge, Tyler; Henter, Heather J.; Kohn, Joshua R.

    2016-06-01

    Beach replenishment is an increasingly popular means to remediate coastal erosion, but no consensus exists regarding how long replenishment affects sandy beach intertidal invertebrates, key components of beach ecosystems. We monitored the intertidal invertebrate community for fifteen months following a replenishment project at eight beaches, each with replenished and control sections, across San Diego County. Nearly all taxa showed major declines in abundance immediately following replenishment. Populations of talitrid amphipods and the bean clam Donax gouldii recovered within one year, sooner than in previous studies. On some beaches, populations of the mole crab Emerita analoga bloomed four months after replenishment and were more numerous on replenished portions of beaches at that time. Mole crab populations subsequently declined and no longer differed by treatment. The polychaete community, composed of Scolelepis sp. and several other numerically important taxa, showed a strong replenishment-induced reduction in abundance that persisted through the end of the study. The large negative effect of replenishment on polychaetes, coupled with their overall importance to the invertebrate community, resulted in a more than twofold reduction in overall invertebrate abundance on replenished beaches at 15 months. Such reductions may have far reaching consequences for sandy beach ecosystems, as community declines can reduce prey availability for shorebirds and fish. As this and other recent studies have revealed longer times for the recovery of intertidal invertebrates than previously observed, longer study periods and more cautious estimates regarding the magnitude, variability, and duration of impacts of beach replenishment for management decision-making are warranted.

  13. Sea level anomalies exacerbate beach erosion

    NASA Astrophysics Data System (ADS)

    Theuerkauf, Ethan J.; Rodriguez, Antonio B.; Fegley, Stephen R.; Luettich, Richard A.

    2014-07-01

    Sea level anomalies are intra-seasonal increases in water level forced by meteorological and oceanographic processes unrelated to storms. The effects of sea level anomalies on beach morphology are unknown but important to constrain because these events have been recognized over large stretches of continental margins. Here, we present beach erosion measurements along Onslow Beach, a barrier island on the U.S. East Coast, in response to a year with frequent sea level anomalies and no major storms. The anomalies enabled extensive erosion, which was similar and in most places greater than the erosion that occurred during a year with a hurricane. These results highlight the importance of sea level anomalies in facilitating coastal erosion and advocate for their inclusion in beach-erosion models and management plans. Sea level anomalies amplify the erosive effects of accelerated sea level rise and changes in storminess associated with global climate change.

  14. Macrodebris and microplastics from beaches in Slovenia.

    PubMed

    Laglbauer, Betty J L; Franco-Santos, Rita Melo; Andreu-Cazenave, Miguel; Brunelli, Lisa; Papadatou, Maria; Palatinus, Andreja; Grego, Mateja; Deprez, Tim

    2014-12-15

    The amount of marine debris in the environment is increasing worldwide, which results in an array of negative effects to biota. This study provides the first account of macrodebris on the beach and microplastics in the sediment (shoreline and infralittoral) in relation to tourism activities in Slovenia. The study assessed the quality and quantity of macrodebris and the quality, size and quantity of microplastics at six beaches, contrasting those under the influences of tourism and those that were not. Beach cleanliness was estimated using the Clean Coast Index. Tourism did not seem to have an effect on macrodebris or microplastic quantity at beaches. Over 64% of macrodebris was plastic, and microplastics were ubiquitous, which calls for classification of plastics as hazardous materials. Standard measures for marine debris assessment are needed, especially in the form of an all-encompassing debris index. Recommendations for future assessments are provided for the Adriatic region. PMID:25440193

  15. What Is the Impact of Beach Debris?

    ERIC Educational Resources Information Center

    Fortner, Rosanne W.; Jax, Dan

    2003-01-01

    Presents a marine education activity. Students construct a web of changes that shows potential problems caused by solid waste on beaches. They then determine whether each change is an increase or a decrease from previous conditions. (Author/SOE)

  16. Differentiating experts' anticipatory skills in beach volleyball.

    PubMed

    Cañal-Bruland, Rouwen; Mooren, Merel; Savelsbergh, Geert J P

    2011-12-01

    In this study, we examined how perceptual-motor expertise and watching experience contribute to anticipating the outcome of opponents' attacking actions in beach volleyball. To this end, we invited 8 expert beach volleyball players, 8 expert coaches, 8 expert referees, and 8 control participants with no beach volleyball experience to watch videos of attack sequences that were occluded at three different times and to predict the outcome of these situations. Results showed that expert players and coaches (who were both perceptual-motor experts) outperformed the expert referees (who were watching experts but did not have the same motor expertise) and the control group in the latest occlusion condition (i.e., at spiker-ball contact). This finding suggests that perceptual-motor expertise may contribute to successful action anticipation in beach volleyball. PMID:22276408

  17. Plastics and beaches: a degrading relationship.

    PubMed

    Corcoran, Patricia L; Biesinger, Mark C; Grifi, Meriem

    2009-01-01

    Plastic debris in Earth's oceans presents a serious environmental issue because breakdown by chemical weathering and mechanical erosion is minimal at sea. Following deposition on beaches, plastic materials are exposed to UV radiation and physical processes controlled by wind, current, wave and tide action. Plastic particles from Kauai's beaches were sampled to determine relationships between composition, surface textures, and plastics degradation. SEM images indicated that beach plastics feature both mechanically eroded and chemically weathered surface textures. Granular oxidation textures were concentrated along mechanically weakened fractures and along the margins of the more rounded plastic particles. Particles with oxidation textures also produced the most intense peaks in the lower wavenumber region of FTIR spectra. The textural results suggest that plastic debris is particularly conducive to both chemical and mechanical breakdown in beach environments, which cannot be said for plastics in other natural settings on Earth. PMID:18834997

  18. Wave Overtopping of a Barrier Beach

    NASA Astrophysics Data System (ADS)

    Thornton, E. B.; Laudier, N.; Macmahan, J. H.

    2009-12-01

    The rate of wave overtopping of a barrier beach is measured and modeled as a first step in modeling the breaching of a beach impounding an ephemeral river. Unique rate of wave overtopping data are obtained from the measure of the Carmel River, California, lagoon filling during a time when the lagoon is closed-off and there is no river inflow. Volume changes are calculated from measured lagoon height changes owing to wave overtopping by a stage-volume curve, then center differenced and averaged to provide volume rates of change in the lagoon. Wave height and period are obtained from CDIP MOPS directional wave spectra data in 15m fronting the beach. Beach morphology was measured by GPS walking surveys and interpolated for beach slopes and berm heights. Three empirical overtopping models by van der Meer and Janssen (1995), Hedges and Reis (1998) and Pullen et al. (2007) with differing parameterizations on wave height, period and beach slope and calibrated using extensive laboratory data obtained over plane, impermeable beaches are compared with the data. In addition, the run-up model by Stockdon et al. (2006) based on field data is examined. Three wave overtopping storm events are considered when morphology data were available less than 2 weeks prior to the event. The models are tuned to fit the data using a reduction factor to account for beach permeability, berm characteristics, non-normal wave incidence and surface roughness influence. It is concluded that the Stockdon et al. (2006) model underestimates run-up as no overtopping is predicted with this model. The three empirical overtopping models behaved similarly well with regression coefficients ranging 0.72 to 0.86 using a reasonable range of reduction factors 0.66 - 0.81 with an average of 0.74.

  19. Monitoring beach changes using GPS surveying techniques

    USGS Publications Warehouse

    Morton, Robert; Leach, Mark P.; Paine, Jeffrey G.; Cardoza, Michael A.

    1993-01-01

    The adaptation of Global Positioning System (GPS) surveying techniques to beach monitoring activities is a promising response to this challenge. An experiment that employed both GPS and conventional beach surveying was conducted, and a new beach monitoring method employing kinematic GPS surveys was devised. This new method involves the collection of precise shore-parallel and shore-normal GPS positions from a moving vehicle so that an accurate two-dimensional beach surface can be generated. Results show that the GPS measurements agree with conventional shore-normal surveys at the 1 cm level, and repeated GPS measurements employing the moving vehicle demonstrate a precision of better than 1 cm. In addition, the nearly continuous sampling and increased resolution provided by the GPS surveying technique reveals alongshore changes in beach morphology that are undetected by conventional shore-normal profiles. The application of GPS surveying techniques combined with the refinement of appropriate methods for data collection and analysis provides a better understanding of beach changes, sediment transport, and storm impacts.

  20. An holistic approach to beach erosion vulnerability assessment.

    PubMed

    Alexandrakis, George; Poulos, Serafim Ε

    2014-01-01

    Erosion is a major threat for coasts worldwide, beaches in particular, which constitute one of the most valuable coastal landforms. Vulnerability assessments related to beach erosion may contribute to planning measures to counteract erosion by identifying, quantifying and ranking vulnerability. Herein, we present a new index, the Beach Vulnerability Index (BVI), which combines simplicity in calculations, easily obtainable data and low processing capacity. This approach provides results not only for different beaches, but also for different sectors of the same beach and enables the identification of the relative significance of the processes involved. It functions through the numerical approximation of indicators that correspond to the mechanisms related to the processes that control beach evolution, such as sediment availability, wave climate, beach morhodynamics and sea level change. The BVI is also intended to be used as a managerial tool for beach sustainability, including resilience to climate change impact on beach erosion. PMID:25123815

  1. Setting conservation targets for sandy beach ecosystems

    NASA Astrophysics Data System (ADS)

    Harris, Linda; Nel, Ronel; Holness, Stephen; Sink, Kerry; Schoeman, David

    2014-10-01

    Representative and adequate reserve networks are key to conserving biodiversity. This begs the question, how much of which features need to be placed in protected areas? Setting specifically-derived conservation targets for most ecosystems is common practice; however, this has never been done for sandy beaches. The aims of this paper, therefore, are to propose a methodology for setting conservation targets for sandy beach ecosystems; and to pilot the proposed method using data describing biodiversity patterns and processes from microtidal beaches in South Africa. First, a classification scheme of valued features of beaches is constructed, including: biodiversity features; unique features; and important processes. Second, methodologies for setting targets for each feature under different data-availability scenarios are described. From this framework, targets are set for features characteristic of microtidal beaches in South Africa, as follows. 1) Targets for dune vegetation types were adopted from a previous assessment, and ranged 19-100%. 2) Targets for beach morphodynamic types (habitats) were set using species-area relationships (SARs). These SARs were derived from species richness data from 142 sampling events around the South African coast (extrapolated to total theoretical species richness estimates using previously-established species-accumulation curve relationships), plotted against the area of the beach (calculated from Google Earth imagery). The species-accumulation factor (z) was 0.22, suggesting a baseline habitat target of 27% is required to protect 75% of the species. This baseline target was modified by heuristic principles, based on habitat rarity and threat status, with final values ranging 27-40%. 3) Species targets were fixed at 20%, modified using heuristic principles based on endemism, threat status, and whether or not beaches play an important role in the species' life history, with targets ranging 20-100%. 4) Targets for processes and 5

  2. 78 FR 35596 - Special Local Regulation; Long Beach Regatta, Powerboat Race, Atlantic Ocean, Long Beach, NY

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-13

    ... Zones; Recurring Events in Captain of the Port Long Island Sound Zone'' in the Federal Register (77 FR... SECURITY Coast Guard 33 CFR Part 100 RIN 1625-AA08 Special Local Regulation; Long Beach Regatta, Powerboat Race, Atlantic Ocean, Long Beach, NY AGENCY: Coast Guard, DHS. ACTION: Notice of Proposed...

  3. Predictive Modeling of Microbial Indicators for Timely Beach Notifications and Advisories at Marine Beaches

    EPA Science Inventory

    Marine beaches are occasionally contaminated by unacceptably high levels of fecal indicator bacteria (FIB) that exceed EPA water quality criteria. Here we describe application of a recent version of the software package Virtual Beach tool (VB 3.0.6) to build and evaluate multiple...

  4. Transformation of Palm Beach Community College to Palm Beach State College: A Case Study

    ERIC Educational Resources Information Center

    Basiratmand, Mehran

    2013-01-01

    The purpose of this single-site case study was to examine the organization and leadership change process of Palm Beach State College, a publicly funded institution in Florida, as it embarked on offering bachelor's degree programs. The study examined the organizational change process and the extent to which Palm Beach State College's organization…

  5. 77 FR 13519 - Safety Zone; Virginia Beach Oceanfront Air Show, Atlantic Ocean, Virginia Beach, VA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-07

    ..., 2008, issue of the Federal Register (73 FR 3316). Public Meeting We do not now plan to hold a public... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Virginia Beach Oceanfront Air Show, Atlantic Ocean, Virginia Beach, VA AGENCY: Coast Guard, DHS. ACTION: Notice of proposed rulemaking....

  6. Advanced Decision-Support for Coastal Beach Health: Virtual Beach 3.0

    EPA Science Inventory

    Virtual Beach is a free decision-support system designed to help beach managers and researchers construct, evaluate, and operate site-specific statistical models that can predict levels of fecal indicator bacteria (FIB) based on environmental conditions that are more readily mea...

  7. 77 FR 50019 - Safety Zone; Cocoa Beach Air Show, Atlantic Ocean, Cocoa Beach, FL

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-20

    ...) 366-9826. SUPPLEMENTARY INFORMATION: Table of Acronyms DHS Department of Homeland Security FR Federal... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Cocoa Beach Air Show, Atlantic Ocean, Cocoa Beach, FL AGENCY: Coast Guard, DHS. ACTION: Temporary final rule. SUMMARY: The Coast Guard...

  8. 76 FR 54703 - Safety Zone; Myrtle Beach Triathlon, Atlantic Intracoastal Waterway, Myrtle Beach, SC

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-02

    ... Triathlon, Atlantic Intracoastal Waterway, Myrtle Beach, SC in the Federal Register (76 FR 124). We received... Intracoastal Waterway, Myrtle Beach, SC AGENCY: Coast Guard, DHS. ACTION: Temporary final rule. SUMMARY: The Coast Guard is establishing a temporary safety zone on the Atlantic Intracoastal Waterway in...

  9. Beach-goer behavior during a retrospectively detected algal bloom at a Great Lakes beach

    EPA Science Inventory

    Algal blooms occur among nutrient rich, warm surface waters and may adversely impact recreational beaches. During July – September 2003, a prospective study of beachgoers was conducted on weekends at a public beach on a Great Lake in the United States. We measured each beac...

  10. Ridge Regression Signal Processing

    NASA Technical Reports Server (NTRS)

    Kuhl, Mark R.

    1990-01-01

    The introduction of the Global Positioning System (GPS) into the National Airspace System (NAS) necessitates the development of Receiver Autonomous Integrity Monitoring (RAIM) techniques. In order to guarantee a certain level of integrity, a thorough understanding of modern estimation techniques applied to navigational problems is required. The extended Kalman filter (EKF) is derived and analyzed under poor geometry conditions. It was found that the performance of the EKF is difficult to predict, since the EKF is designed for a Gaussian environment. A novel approach is implemented which incorporates ridge regression to explain the behavior of an EKF in the presence of dynamics under poor geometry conditions. The basic principles of ridge regression theory are presented, followed by the derivation of a linearized recursive ridge estimator. Computer simulations are performed to confirm the underlying theory and to provide a comparative analysis of the EKF and the recursive ridge estimator.

  11. PUSCH RIDGE WILDERNESS, ARIZONA.

    USGS Publications Warehouse

    Hinkle, Margaret E.; Ryan, George S.

    1984-01-01

    On the basis of a mineral survey, the Pusch Ridge Wilderness, located at the northern boundary of the city of Tucson, Arizona, offers little or no promise for the occurrence of energy resources. Only one area contains a probable potential for small, isolated contact-metamorphic deposits containing copper, molybdenum, tungsten, lead, and zinc. This area is located around the southwestern end of Pusch Ridge, adjacent to a residential area.

  12. Morphodynamics of intertidal bars near a seawall on a macrotidal beach, Wissant Bay, northern France

    NASA Astrophysics Data System (ADS)

    Sedrati, M.; Anthony, E.

    2009-04-01

    Several studies on beaches with intertidal bar-trough (ridge-and-runnel) systems in settings with relatively large tidal ranges (> 3 m) have focused on cross-shore bar mobility; however a few recent studies have drawn attention to the potential role of longshore transport induced by a mix of wave-tide and wind-forced longshore currents in the morphodynamics of the bars and troughs. The aim of this paper is to briefly highlight the relationship between wind-forced currents on the shallow intertidal zone and rapid intertidal bar-trough morphological response on a macrotidal beach. Fieldwork was conduced on Wissant beach, Wissant Bay, northern France, from 7 to 23 March, 2006. During the experiment, the beach (oriented NE-SW) exhibited three intertidal bar-trough systems and the upper bar was directly attached to a seawall. Seven digital elevation models (DEMs) were generated from high-resolution topographic surveys. Hydrodynamic measurements were obtained from five currentmeters (2 S4 and 3 ADCP) deployed on the bars crests and on the upper beach trough. Wave characteristics were obtained from the measured time series by spectral analysis using Fast Fourier Transforms. Wind speed and direction on the beach were measured using a portable weather station. The mean wind speed and directions averaged every three hours highlight closely-spaced high-energy events during the experiment, with long phases of significant lateral wind stress (NE to ENE). The measured waves and currents showed rapid and strong response to both the changes in wind speed and direction. Longshore currents measured during the experiment on the upper intertidal bar-trough system showed a clear SW flow pattern in response to NE to ENE wind approach directions while the currents in the lower intertidal zone flowed northeastward during the flood, following the coastline, and southwestward during the ebb in response to the tidal current modulation. Strong longshore migration of the upper intertidal bar

  13. Geomorphology and dynamics of a traveling cuspate foreland, Authie estuary, France

    NASA Astrophysics Data System (ADS)

    Hesp, Patrick A.; Ruz, Marie-Hélène; Hequette, Arnaud; Marin, Denis; Miot da Silva, Graziela

    2016-02-01

    Cuspate forelands or salients occur all over the world in lakes, estuaries and on ocean shores, yet there have been few studies conducted on traveling cuspate forelands (or salients), that is, forelands that migrate or travel alongshore. This paper presents a study of a traveling foreland in the Authie estuary, France, termed the Bec du Perroquet. Historical shoreline changes may be traced from the 1200's AD and the region has experienced both marked intertidal-subtidal accretion extending from the south, and massive erosion in the north since this period. An analysis of aerial photographs from 1947 until the present shows that the original Bec foreland was established at the mouth of the Authie estuary, but gradually disappeared by the 1960's and a new foreland developed in the middle of the northern-central portion of the bay. This foreland was composed of a suite of foredune ridges which have been successively eroded on the northern margin and initiated on the southern margin as the foreland traveled or migrated southwards. As the foreland traveled south, from 1947 to 2009 the northern part of the bay retreated more than 350 m, while mid-bay, the coastline retreated ~ 215 m. As the foreland evolves and migrates, incipient foredunes can develop rapidly (e.g. 18 ridges formed in an 11 week period), while at other times the ridges form slowly and may be eroded and disappear. Two or more foredune ridges may blend into a single ridge over time depending on the initial degree of vegetation cover on the ridge and swale set. Aeolian processes in dune swales are much more important in this system than in typical prograding foredune plain systems due to the sometimes marked lack of vegetation colonization in the swales following foredune ridge development, and aeolian deflation of the swales (along with blowout development) is important particularly when they become open conduits to the beach as erosion of the NW foreland proceeds. The ages of each of the surviving ridges

  14. Long or short? Investigating the effect of beach length and other environmental parameters on macrofaunal assemblages of Maltese pocket beaches

    NASA Astrophysics Data System (ADS)

    Deidun, A.; Schembri, P. J.

    2008-08-01

    Despite numerous published studies that have evaluated the influence of different physical parameters, including beach slope, sediment organic content and grain size, on beach macrofaunal assemblages, very few studies have investigated the influence of beach length on biotic attributes of the same assemblages. Four beaches on the Maltese Islands were sampled using pitfall traps at night for eight consecutive seasons during 2001-2003. Macrofaunal collections were dominated by arthropods, mostly isopods (especially Tylos europaeus) and tenebrionid beetles (especially Phaleria spp.). The environmental variables of beach slope, exposure to wave action, sediment organic content, mean particle diameter, log beach length, beach width and the beach deposit index (BDI) were regressed against a number of biotic parameters, including log individual abundance, total species, Shannon-Wiener ( H') diversity index value and the psammophilic fraction of the total species collected, whilst BIO-ENV and NMDS were used to identify the physical parameter which could best explain observed biotic patterns. RELATE was used to assess the long-term persistence of macrofaunal assemblages on beaches of different lengths. Results from this study suggest that, whilst the influence of beach length and beach width on individual abundance and total species number is unimportant, these 'beach-area' parameters may affect the taxonomic composition of a beach assemblage, mainly in terms of the psammophilic fraction of assemblages, as well as the permanence of macrofaunal assemblages on a beach. Shorter and narrower beaches were found to be more prone to sporadic and random events of colonisation by euryoecious species. In the absence of human disturbance and mass mortality events, beaches of limited dimensions can still maintain stable macrofaunal assemblages. Individual abundance and total species number could not be related to a single or small suite of physical parameters. The study further

  15. Inner shelf morphologic controls on the dynamics of the beach and bar system, Fire Island, New York

    USGS Publications Warehouse

    Hapke, Cheryl J.; Schwab, William C.; Gayes, P.; McCoy, Clay; Viso, Richard; Lentz, Erika E.

    2011-01-01

    he mechanism of sediment exchange between offshore sand ridges and the beach at Fire Island, New York is largely unknown. However, recent evidence from repeat nearshore bathymetry surveys, coupled with the complex but consistent bar morphology and patterns of shoreline change demonstrate that there is a feedback occurring between the regional geologic framework and modern processes. Analysis of bathymetric survey data provides direct confirmation that the offshore ridges are connected to the shoreface and are spatially persistent. The fixed nature of the nearshore morphology is further supported by time series camera data that indicate persistent bars with breaks that re-form in the same locations. A long-term time series of shoreline change shows distinct zones of erosion and accretion that are pervasive over time scales greater than a half-century, and their length-scales are similar to the spacing of the offshore ridge-trough system. The first-order geologic framework is responsible for the existence and locations of the ridges and troughs, which then influence the morphodynamics of the beach and bar system.

  16. Threats to sandy beach ecosystems: A review

    NASA Astrophysics Data System (ADS)

    Defeo, Omar; McLachlan, Anton; Schoeman, David S.; Schlacher, Thomas A.; Dugan, Jenifer; Jones, Alan; Lastra, Mariano; Scapini, Felicita

    2009-01-01

    We provide a brief synopsis of the unique physical and ecological attributes of sandy beach ecosystems and review the main anthropogenic pressures acting on the world's single largest type of open shoreline. Threats to beaches arise from a range of stressors which span a spectrum of impact scales from localised effects (e.g. trampling) to a truly global reach (e.g. sea-level rise). These pressures act at multiple temporal and spatial scales, translating into ecological impacts that are manifested across several dimensions in time and space so that today almost every beach on every coastline is threatened by human activities. Press disturbances (whatever the impact source involved) are becoming increasingly common, operating on time scales of years to decades. However, long-term data sets that describe either the natural dynamics of beach systems or the human impacts on beaches are scarce and fragmentary. A top priority is to implement long-term field experiments and monitoring programmes that quantify the dynamics of key ecological attributes on sandy beaches. Because of the inertia associated with global climate change and human population growth, no realistic management scenario will alleviate these threats in the short term. The immediate priority is to avoid further development of coastal areas likely to be directly impacted by retreating shorelines. There is also scope for improvement in experimental design to better distinguish natural variability from anthropogenic impacts. Sea-level rise and other effects of global warming are expected to intensify other anthropogenic pressures, and could cause unprecedented ecological impacts. The definition of the relevant scales of analysis, which will vary according to the magnitude of the impact and the organisational level under analysis, and the recognition of a physical-biological coupling at different scales, should be included in approaches to quantify impacts. Zoning strategies and marine reserves, which have not

  17. Internal structure of a barrier beach as revealed by ground penetrating radar (GPR): Chesil beach, UK

    NASA Astrophysics Data System (ADS)

    Bennett, Matthew R.; Cassidy, Nigel J.; Pile, Jeremy

    2009-03-01

    Chesil Beach (Dorset) is one of the most famous coastal landforms on the British coast. The gravel beach is over 18 km long and is separated for much of its length from land by a tidal lagoon known as The Fleet. The beach links the Isle of Portland in the east to the mainland in the west. Despite its iconic status there is little available information on its internal geometry and evolutionary history. Here we present a three-fold model for the evolution of Chesil Beach based on a series of nine ground penetrating radar (GPR) traverses located at three sites along its length at Abbotsbury, Langton Herring and at Ferry Bridge. The GPR traverses reveal a remarkably consistent picture of the internal structure of this barrier beach. The first phase of evolution involves the landward transgression of a small sand and gravel beach which closed upon the coast leading to deposition of freshwater peat between 5 and 7 k yr BP. The second evolutionary phase involves the 'bulking-out' of the beach during continued sea level rise, but in the presence of abundant gravel supplied by down-drift erosion of periglacial slope deposits. This episode of growth was associated with a series of washover fans which accumulated on the landward flank of the barrier increasing its breadth and height but without significant landward transgression of the barrier as a whole. The final phase in the evolution of Chesil Beach involves the seaward progradation of the beach crest and upper beach face associated with continued sediment abundance, but during a still-stand or slight fall in relative sea level. This phase may provide further evidence of a slight fall in relative sea level noted elsewhere along the South Coast of Britain and dated to between 1.2 and 2.4 k yr BP. Subsequently the barrier appears to have become largely inactive, except for the reworking of sediment on the beach face during storm events. The case study not only refines the evolutionary picture of Chesil Beach, but

  18. Beach science in the Great Lakes

    USGS Publications Warehouse

    Nevers, Meredith B.; Byappanahalli, Murulee N.; Edge, Thomas A.; Whitman, Richard L.

    2014-01-01

    Monitoring beach waters for human health has led to an increase and evolution of science in the Great Lakes, which includes microbiology, limnology, hydrology, meteorology, epidemiology, and metagenomics, among others. In recent years, concerns over the accuracy of water quality standards at protecting human health have led to a significant interest in understanding the risk associated with water contact in both freshwater and marine environments. Historically, surface waters have been monitored for fecal indicator bacteria (fecal coliforms, Escherichia coli, enterococci), but shortcomings of the analytical test (lengthy assay) have resulted in a re-focusing of scientific efforts to improve public health protection. Research has led to the discovery of widespread populations of fecal indicator bacteria present in natural habitats such as soils, beach sand, and stranded algae. Microbial source tracking has been used to identify the source of these bacteria and subsequently assess their impact on human health. As a result of many findings, attempts have been made to improve monitoring efficiency and efficacy with the use of empirical predictive models and molecular rapid tests. All along, beach managers have actively incorporated new findings into their monitoring programs. With the abundance of research conducted and information gained over the last 25 years, “Beach Science” has emerged, and the Great Lakes have been a focal point for much of the ground-breaking work. Here, we review the accumulated research on microbiological water quality of Great Lakes beaches and provide a historic context to the collaborative efforts that have advanced this emerging science.

  19. USING PUBLIC-DOMAIN MODELS TO ESTIMATE BEACH BACTERIA CONCENTRATIONS

    EPA Science Inventory

    Stretches of beach along popular Huntington Beach, California are occassionally closed to swimming due to high levels of bacteria. One hypothesized source is the treated wastewater plume from the Orange County Sanitation District's (OCSD) ocean outfall. While three independent sc...

  20. Route No. 1 near east end, view toward Overton Beach ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Route No. 1 near east end, view toward Overton Beach and Lake Mead, view to northeast - Route No. 1-Overton-Lake Mead Road, Between Overton Beach & Park Boundary, 6 miles south of Overton, Overton, Clark County, NV

  1. Monsoon-influenced variations in morphology and sediment of a mesotidal beach on the Mekong River delta coast

    NASA Astrophysics Data System (ADS)

    Tamura, Toru; Horaguchi, Keishi; Saito, Yoshiki; Nguyen, Van Lap; Tateishi, Masaaki; Ta, Thi Kim Oanh; Nanayama, Futoshi; Watanabe, Kazuaki

    2010-03-01

    A mesotidal beach on the Mekong River delta coast exhibits unique patterns of river sediment discharge and experiences reversals of ocean wave directions in response to the summer and winter monsoons. We analyzed long-term changes of the shoreline since 1936 from past topographic maps and satellite images, and short-term changes in geomorphology and sedimentology by undertaking repeated field surveys between November 2005 and February 2008 along six shore-normal beach transects. The shoreline of the Mekong River delta coast has changed asymmetrically over the last 70 years in response to net southwestward sediment transport related to dry northeasterly winter monsoons. During the summer rainy season, large volumes of sediments are discharged from the river; at this time, wave direction is reversed in response to the relatively weak southwesterly summer monsoon. Mud and very fine sand in the surface sediments of the northeastern (updrift) beach transects tend to be removed during winter, suggesting that the sediment supplied from the river during summer is temporarily deposited near the river mouth and later transported southwestward during the winter monsoon. The relief of intertidal bars on the beach increased during winter in response to higher waves. However, previous studies have suggested that higher waves flatten bars. We hypothesize that the increase in relief that we observed is related to a wide and shallow subtidal delta-front platform that attenuates ocean waves at all times other than at high tide. The beach profile varies longshore: the accreting to stable beach dips seaward at a gradient of about 1/80 with up to three longshore intertidal bars, classified here as either slip-face bars or low-amplitude ridges. In contrast, the eroding beach profile is much steeper (1/20-1/40) and linear without intertidal bars, and is similar in form to a low-tide terrace. Because there is little variation of wave size and grain size within the study area, we consider

  2. Fingermark ridge drift.

    PubMed

    De Alcaraz-Fossoul, Josep; Roberts, Katherine A; Feixat, Carme Barrot; Hogrebe, Gregory G; Badia, Manel Gené

    2016-01-01

    Distortions of the fingermark topography are usually considered when comparing latent and exemplar fingerprints. These alterations are characterized as caused by an extrinsic action, which affects entire areas of the deposition and alters the overall flow of a series of contiguous ridges. Here we introduce a novel visual phenomenon that does not follow these principles, named fingermark ridge drift. An experiment was designed that included variables such as type of secretion (eccrine and sebaceous), substrate (glass and polystyrene), and degrees of exposure to natural light (darkness, shade, and direct light) indoors. Fingermarks were sequentially visualized with titanium dioxide powder, photographed and analyzed. The comparison between fresh and aged depositions revealed that under certain environmental conditions an individual ridge could randomly change its original position regardless of its unaltered adjacent ridges. The causes of the drift phenomenon are not well understood. We believe it is exclusively associated with intrinsic natural aging processes of latent fingermarks. This discovery will help explain the detection of certain dissimilarities at the minutiae/ridge level; determine more accurate "hits"; identify potentially erroneous corresponding points; and rethink identification protocols, especially the criteria of "no single minutiae discrepancy" for a positive identification. PMID:26646735

  3. Burrowing inhibition by fine textured beach fill: Implications for recovery of beach ecosystems

    NASA Astrophysics Data System (ADS)

    Viola, Sloane M.; Hubbard, David M.; Dugan, Jenifer E.; Schooler, Nicholas K.

    2014-10-01

    Beach nourishment is often considered the most environmentally sound method of maintaining eroding shorelines. However, the ecological consequences are poorly understood. Fill activities cause intense disturbance and high mortality and have the potential to alter the diversity, abundance, and distribution of intertidal macroinvertebrates for months to years. Ecological recovery following fill activities depends on successful recolonization and recruitment of the entire sandy intertidal community. The use of incompatible sediments as fill material can strongly affect ecosystem recovery. We hypothesized that burrowing inhibition of intertidal animals by incompatible fine fill sediments contributes to ecological impacts and limits recovery in beach ecosystems. We experimentally investigated the influence of intertidal zone and burrowing mode on responses of beach invertebrates to altered sediment texture (28-38% fines), and ultimately the potential for colonization and recovery of beaches disturbed by beach filling. Using experimental trials in fill material and natural beach sand, we found that the mismatched fine fill sediments significantly inhibited burrowing of characteristic species from all intertidal zones, including sand crabs, clams, polychaetes, isopods, and talitrid amphipods. Burrowing performance of all five species we tested was consistently reduced in the fill material and burrowing was completely inhibited for several species. The threshold for burrowing inhibition by fine sediment content in middle and lower beach macroinvertebrates varied by species, with highest sensitivity for the polychaete (4% fines, below the USA regulatory limit of 10% fines), followed by sand crabs and clams (20% fines). These results suggest broader investigation of thresholds for burrowing inhibition in fine fill material is needed for beach animals. Burrowing inhibition caused by mismatched fill sediments exposes beach macroinvertebrates to stresses, which could depress

  4. Ridged Layer Outcrop

    NASA Technical Reports Server (NTRS)

    2004-01-01

    15 August 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a strange ridged pattern developed in an eroding layer of material on the floor of a Labyrinthus Noctis depression in the Valles Marineris system. The ridges bear some resemblance to ripple-like dunes seen elsewhere on Mars, but they are linked to the erosion of a specific layer of material--i.e., something in the rock record of Mars. Similar ridged textures are found in eroded dark-toned mantling layers in regions as far away as northern Sinus Meridiani and Mawrth Vallis. The explanation for these landforms is as elusive as this image is evocative. The image is located near 8.2oS, 93.6oW, and covers an area 3 km (1.9 mi) across. The scene is illuminated by sunlight from the upper left.

  5. Monitoring of beach enteromorpha variation with near shore video

    NASA Astrophysics Data System (ADS)

    Hu, Yali; Yu, Xinsheng; Yan, Zhijin; Yi, Weidong

    2014-07-01

    Beach is an important coastal protective barrier and tourism resources. Beach environment monitoring can help beach managers to make feasible decisions. Digital image of video monitoring technology can provide high resolution information of temporal and spatial variation of near shore in real time. The application of Video monitoring technology has been implemented in Qingdao's Shilaoren beach. The clustering method based on Gaussian mixture model is applied to extract beach enteromorpha changs for the digital images. Analysis results show that, the period of enteromorpha in Qingdao's Shilaoren beach was mainly from the early July to the mid-August in 2011, and the decline of enteromorpha is mainly associated with the rising temperature in the mid-August. Storm has significant impact on the beach enteromorpha. Tourists' activity space on the beach will decrease due to the enteromorpha covering on the beach, which affects beach tourism activities. Therefore, it's necessary to make preventive measures to avoid enteromorpha piling up on the beach, which is of great importance to the bathing beach environment and tourism development.

  6. Beach Sand Analysis for Indicators of Microbial Contamination

    EPA Science Inventory

    Traditional beach monitoring has focused on water quality, with little attention paid to health risks associated with beach sand. Recent research has reported that fecal indicator bacteria, as well as human pathogens can be found in beach sand and may constitute a risk to human h...

  7. 103. VIEW OF BEACH STRUCTURES ON NORTHWEST SIDE OF PIER, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    103. VIEW OF BEACH STRUCTURES ON NORTHWEST SIDE OF PIER, LOOKING SOUTHEAST; PACIFIC ELECTRIC RAILWAY CAR (UPPER LEFT), CONCESSION STANDS (LOWER LEFT), BANDSHELL (RIGHT), AND PIER IN BACKGROUND Photograph #5352-HB. Photographer unknown, c. 1914 - Huntington Beach Municipal Pier, Pacific Coast Highway at Main Street, Huntington Beach, Orange County, CA

  8. Tracer Studies In A Laboratory Beach Subjected To Waves

    EPA Science Inventory

    This work investigated the washout of dissolved nutrients from beaches due to waves by conducting tracer studies in a laboratory beach facility. The effects of waves were studied in the case where the beach was subjected to the tide, and that in which no tidal action was present...

  9. POLYMERASE CHAIN REACTION (PCR) TECHNOLOGY IN VISUAL BEACH

    EPA Science Inventory

    In 2000, the US Congress passed the Beaches Environmental Assessment and Coastal Health Act under which the EPA has the mandate to manage all significant public beaches by 2008. As a result, EPA, USGS and NOAA are developing the Visual Beach program which consists of software eq...

  10. Beaches in Motion. Interaction and Environmental Change. Secondary.

    ERIC Educational Resources Information Center

    Lee County School District, Ft. Myers, FL. Dept. of Environmental Education and Instructional Development Services.

    The terms "high energy" and "low energy" refer to the amount of energy a wave has that reaches the face of a beach. In this student guide, two types of beaches are investigated. The objective is to be able to identify whether a beach is of high or low energy. Background information is provided, as well as instructions and worksheets for activities…

  11. 107. VIEW OF BEACH DEVELOPMENT ON NORTHWEST SIDE OF PIER, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    107. VIEW OF BEACH DEVELOPMENT ON NORTHWEST SIDE OF PIER, LOOKING SOUTH-SOUTHEAST. SECTION OF PIER IS IN BACKGROUND Photograph #1579-HB. Photographer unknown, c. 1930-31 prior to replacement of original light standards in 1930-31 - Huntington Beach Municipal Pier, Pacific Coast Highway at Main Street, Huntington Beach, Orange County, CA

  12. Beach Cusps: Spatial distribution and time evolution at Massaguaçú beach (SP), Brazil

    NASA Astrophysics Data System (ADS)

    dos Santos, H. H.; Siegle, E.; Sousa, P. H.

    2013-05-01

    Beach cusps are crescentic morphological structures observed on the foreshore of beaches characterized by steep seaward protruding extensions, called cusp horns, and gently sloped landward extensions, called cusp embayments. Their formation depends on the grain size, beach slope, tidal range and incoming waves. Cusps are best developed on gravel or shingle beaches, small tidal range with a large slope for incoming waves generate a well-developed swash excursion. These structures are quickly responding to wave climate and tidal range, changing the position of the rhythmic features on the beach face. Beach cusps are favored by normal incoming waves, while oblique waves tend to wash these features out. This study aims to analyze the spatial distribution and temporal evolution of rhythmic features such as beach cusps in Massaguaçú embayment (Caraguatatuba, northern coast of São Paulo, Brazil). This embayment has an extension of 7.5 km with reflective beaches cusped mainly in its more exposed central portion. The data set for this study consists of a series of video images (Argus system), covering a stretch of the beach. Visible beach cusps were digitalized from these rectified images. Results obtained from the images were related to the wave climate, water level and the storm surges. Results show that the cusps on the upper portion of the foreshore were more regular and present than the cusps on the lower portion of the foreshore due to the tidal modulation of wave action. The cusp spacing on the upper portion of the foreshore is of about 38 m and the lower portion of the foreshore is of about 28 m and their presence was correlated with the wave direction and water elevation. As expected, waves approaching with shore-normal angles (southeast direction) were favorable to the formation of beach cusps while the waves from the southwest, south, east and northeast generated a longshore current that reduced or destroyed any rhythmic feature. Other important forcing was

  13. Beaches, Dunes, and Barrier Islands. Habitat Pac.

    ERIC Educational Resources Information Center

    Fish and Wildlife Service (Dept. of Interior), Washington, DC.

    The materials in this educational packet are designed for use with students in grades 4 through 7. They consist of a leader overview, teaching guides and student data sheets for three activities, and a poster. The leader overview describes the nature of beaches, dunes, and barrier islands, tracing their development, settlement, and management and…

  14. An Interview with Beatrice Beach Szekely

    ERIC Educational Resources Information Center

    Steiner-Khamsi, Gita

    2007-01-01

    This article presents an interview with Beatrice Beach Szekely, a comparative education scholar that specialized in the Soviet Union. She was editor of the journal "Soviet Education" from 1970 to 1989. During the interview, Szekely talked about how she became personally involved in Russian/Soviet studies of education. She related that her interest…

  15. Cosmology at the Beach Lecture: Wayne Hu

    ScienceCinema

    Wayne Hu

    2010-01-08

    Wayne Hu lectures on Secondary Anisotropy in the CMB. The lecture is the first in a series of 3 he delivered as part of the "Cosmology at the Beach" winter school organized by Berkeley Lab's George Smoot in Los Cabos, Mexico from Jan. 12-16, 2009.

  16. Erosion in the Beaches of Crete

    NASA Astrophysics Data System (ADS)

    Synolakis, C. E.; Foteinis, S.; Voukouvalas, V.; Kalligeris, N.

    2009-04-01

    In the past decade, erosion rates for the coastlines of Greece are rapidly increasing. Many beaches on the northern coast of the island have substantially retreated, while others have disappeared or will disappear within the present or the following decade if no action is taken. For the better understanding and visualization of the current situation, specific examples of rapid erosion are described and afterwards we speculate as to the causes. We infer that, as in other parts of the Mediterranean, the causes are anthropogenic and include removal of sand dunes to build roads, sand mining from beaches and rivers, permanent building construction within the active coastal zone, on or too close to shoreline, and poor design of coastal structures. The reason behind the rapid erosion of Greece coastlines is the complete lack of any semblance of coastal zone management and antiquated legislation. We conclude that unless urgent measures for the protection and even salvation of the beaches are taken and if the sand mining and dune removal does not stop, then several beaches will disappear within the present and the following decade.

  17. Cosmology at the Beach Lecture: Wayne Hu

    SciTech Connect

    Wayne Hu

    2009-03-02

    Wayne Hu lectures on Secondary Anisotropy in the CMB. The lecture is the first in a series of 3 he delivered as part of the "Cosmology at the Beach" winter school organized by Berkeley Lab's George Smoot in Los Cabos, Mexico from Jan. 12-16, 2009.

  18. Ridge from strings

    NASA Astrophysics Data System (ADS)

    Braun, M. A.; Pajares, C.; Vechernin, V. V.

    2015-04-01

    In the colour string picture with fusion and percolation it is shown that long-range azimuthal-rapidity correlations (ridge) can arise from the superposition of many events with exchange of clusters of different number of strings and not from a single event. Relation of the ridge with the flow harmonics coefficients is derived. By direct Monte Carlo simulations, in the technique previously used to calculate these coefficients, ridge correlations are calculated for AA, pA and pp collisions. The azimuthal anisotropy follows from the assumed quenching of the emitted particles in the strong colour fields inside string clusters. It is confirmed that in pp collisions the ridge structure only appears in rare events with abnormally high multiplicity. Comparison with the experimental data shows a good agreement. Good agreement is also found for pPb collisions. For AA collisions a reasonable agreement is found for both near-side and away-side angular correlations although it worsens at intermediate angles.

  19. Vegetation controls on the maximum size of coastal dunes

    NASA Astrophysics Data System (ADS)

    Durán, Orencio; Moore, Laura J.

    2013-10-01

    Coastal dunes, in particular foredunes, support a resilient ecosystem and reduce coastal vulnerability to storms. In contrast to dry desert dunes, coastal dunes arise from interactions between biological and physical processes. Ecologists have traditionally addressed coastal ecosystems by assuming that they adapt to preexisting dune topography, whereas geomorphologists have studied the properties of foredunes primarily in connection to physical, not biological, factors. Here, we study foredune development using an ecomorphodynamic model that resolves the coevolution of topography and vegetation in response to both physical and ecological factors. We find that foredune growth is eventually limited by a negative feedback between wind flow and topography. As a consequence, steady-state foredunes are scale invariant, which allows us to derive scaling relations for maximum foredune height and formation time. These relations suggest that plant zonation (in particular for strand "dune-building" species) is the primary factor controlling the maximum size of foredunes and therefore the amount of sand stored in a coastal dune system. We also find that aeolian sand supply to the dunes determines the timescale of foredune formation. These results offer a potential explanation for the empirical relation between beach type and foredune size, in which large (small) foredunes are found on dissipative (reflective) beaches. Higher waves associated with dissipative beaches increase the disturbance of strand species, which shifts foredune formation landward and thus leads to larger foredunes. In this scenario, plants play a much more active role in modifying their habitat and altering coastal vulnerability than previously thought.

  20. Vegetation controls on the maximum size of coastal dunes

    PubMed Central

    Durán, Orencio; Moore, Laura J.

    2013-01-01

    Coastal dunes, in particular foredunes, support a resilient ecosystem and reduce coastal vulnerability to storms. In contrast to dry desert dunes, coastal dunes arise from interactions between biological and physical processes. Ecologists have traditionally addressed coastal ecosystems by assuming that they adapt to preexisting dune topography, whereas geomorphologists have studied the properties of foredunes primarily in connection to physical, not biological, factors. Here, we study foredune development using an ecomorphodynamic model that resolves the coevolution of topography and vegetation in response to both physical and ecological factors. We find that foredune growth is eventually limited by a negative feedback between wind flow and topography. As a consequence, steady-state foredunes are scale invariant, which allows us to derive scaling relations for maximum foredune height and formation time. These relations suggest that plant zonation (in particular for strand “dune-building” species) is the primary factor controlling the maximum size of foredunes and therefore the amount of sand stored in a coastal dune system. We also find that aeolian sand supply to the dunes determines the timescale of foredune formation. These results offer a potential explanation for the empirical relation between beach type and foredune size, in which large (small) foredunes are found on dissipative (reflective) beaches. Higher waves associated with dissipative beaches increase the disturbance of strand species, which shifts foredune formation landward and thus leads to larger foredunes. In this scenario, plants play a much more active role in modifying their habitat and altering coastal vulnerability than previously thought. PMID:24101481

  1. Trophic niche shifts driven by phytoplankton in sandy beach ecosystems

    NASA Astrophysics Data System (ADS)

    Bergamino, Leandro; Martínez, Ana; Han, Eunah; Lercari, Diego; Defeo, Omar

    2016-10-01

    Stable isotopes (δ13C and δ15N) together with chlorophyll a and densities of surf diatoms were used to analyze changes in trophic niches of species in two sandy beaches of Uruguay with contrasting morphodynamics (i.e. dissipative vs. reflective). Consumers and food sources were collected over four seasons, including sediment organic matter (SOM), suspended particulate organic matter (POM) and the surf zone diatom Asterionellopsis guyunusae. Circular statistics and a Bayesian isotope mixing model were used to quantify food web differences between beaches. Consumers changed their trophic niche between beaches in the same direction of the food web space towards higher reliance on surf diatoms in the dissipative beach. Mixing models indicated that A. guyunusae was the primary nutrition source for suspension feeders in the dissipative beach, explaining their change in dietary niche compared to the reflective beach where the proportional contribution of surf diatoms was low. The high C/N ratios in A. guyunusae indicated its high nutritional value and N content, and may help to explain the high assimilation by suspension feeders at the dissipative beach. Furthermore, density of A. guyunusae was higher in the dissipative than in the reflective beach, and cell density was positively correlated with chlorophyll a only in the dissipative beach. Therefore, surf diatoms are important drivers in the dynamics of sandy beach food webs, determining the trophic niche space and productivity. Our study provides valuable insights on shifting foraging behavior by beach fauna in response to changes in resource availability.

  2. The effect of beach slope on tidal influenced saltwater intrusion

    NASA Astrophysics Data System (ADS)

    Zhao, Z.; Shen, C.; Jin, G.; Xin, P.; Hua, G.; Tao, X.; Zhao, J.

    2015-12-01

    Beach slope changes the tidal induced saltwater-freshwater circulations in coastal aquifers. However, the effect of beach slope on tidal influenced saltwater-freshwater mixing process is far from understood. Based on sand flume experiments and numerical simulations, we investigated the intrusion process of saltwater into freshwater under tidal forcing and variable beach slopes. The sand flume experiment results show that milder slope induces larger upper saline plume (USP) and seaward salt wedge interface (SWI) under tidal forcing. While, the steady state SWI keeps stagnant with different beach slopes. Consistent with the previous research, our numerical simulations also show a lager flux exchange across the milder beach induced by the tidal fluctuations. The groundwater table fluctuates more intensify with deeper beach slope. The next step of our study will pay attention to the effect of beach slope on the instability of USP which induces the salt-fingering flow.

  3. Quantifying Beach Response to Episodic Large Wave Events, a Predictive Empirical Model, Ocean Beach, San Francisco, CA

    NASA Astrophysics Data System (ADS)

    Hansen, J. E.; Barnard, P. L.

    2006-12-01

    Predicting beach response on an event scale is extremely difficult due to highly variable spatial and temporal conditions, lack of data on antecedent beach morphology, generic model shortcomings, and uncertainty of local forcing parameters. Each beach system is unique and classical beach erosion models may not be applicable to many high-energy beaches, especially those receiving large long-period waves. Therefore, developing an empirical model is the best way to predict future beach response at a given site. Based on 12 closely spaced (temporally) GPS topographic surveys during the winter of 2005-2006 at Ocean Beach, in San Francisco, California, we have developed a predictive empirical model that relates sub-aerial beach response to observed wave height, period, and direction. The model will provide important information to coastal managers, who will be able to better predict and mitigate possible loss from a forecasted wave event. Ocean Beach, located immediately south of the Golden Gate in San Francisco, is a high-energy, intermediate- slope beach that is exposed to waves generated in both the North and South Pacific. Winter breaking wave heights frequently reach 4 m and can exceed 7 m, with periods sometimes greater than 20 s. Our observations demonstrate that large seasonal variations in the sub-aerial beach profile are likely forced by several single large wave events. These events have led to the partial destruction of a recreational parking lot at the south end of the beach where an erosion hot spot is currently located, and continued erosion will threaten other parts of public infrastructure. This study, in combination with other ongoing research at Ocean Beach, will provide valuable insight that will not only aid local personnel in their management decisions but also contribute to a better understanding of sediment transport at high-energy beaches.

  4. Ridge network in crumpled paper.

    PubMed

    Andresen, Christian André; Hansen, Alex; Schmittbuhl, Jean

    2007-08-01

    The network formed by ridges in a straightened sheet of crumpled paper is studied using a laser profilometer. Square sheets of paper were crumpled into balls, unfolded, and their height profile measured. From these profiles the imposed ridges were extracted as networks. Nodes were defined as intersections between ridges, and links as the various ridges connecting the nodes. Many network and spatial properties have been investigated. The tail of the ridge length distribution was found to follow a power law, whereas the shorter ridges followed a log-normal distribution. The degree distribution was found to have an exponentially decaying tail, and the degree correlation was found to be disassortative. The facets created by the ridges and the Voronoi diagram formed by the nodes have also been investigated. PMID:17930105

  5. Ridge regression processing

    NASA Technical Reports Server (NTRS)

    Kuhl, Mark R.

    1990-01-01

    Current navigation requirements depend on a geometric dilution of precision (GDOP) criterion. As long as the GDOP stays below a specific value, navigation requirements are met. The GDOP will exceed the specified value when the measurement geometry becomes too collinear. A new signal processing technique, called Ridge Regression Processing, can reduce the effects of nearly collinear measurement geometry; thereby reducing the inflation of the measurement errors. It is shown that the Ridge signal processor gives a consistently better mean squared error (MSE) in position than the Ordinary Least Mean Squares (OLS) estimator. The applicability of this technique is currently being investigated to improve the following areas: receiver autonomous integrity monitoring (RAIM), coverage requirements, availability requirements, and precision approaches.

  6. Integrated protecting plan for beach erosion. A case study in Plaka beach, E. Crete, Greece

    NASA Astrophysics Data System (ADS)

    Petrakis, Stelios; Alexandrakis, George; Kozyrakis, George; Hatziyanni, Eleni; Kampanis, Nikolaos

    2015-04-01

    Coastal zones are among the most active areas on Earth, being subjected to extreme wind / wave conditions, thus vulnerable to erosion. In Greece and Crete in particular, beach zones are extremely important for the welfare of the inhabitants, since, apart for the important biological and archaeological value of the beach zones, the socio-economic value is critical since a great number of human activities are concentrated in such areas (touristic facilities, fishing harbors etc.). The present study investigates the erosional procedures observed in Plaka beach, E. Crete, Greece, a highly touristic developed area with great archaeological interest and proposes a cost-effective solution. The factors taken into consideration for the proposed solution in reducing the erosion of the beach were the study of the climatological, geological and geomorphological regime of the area, the recent (~70 years) shifting of the coastline through the study of topographic maps, aerial photographs and satellite images, the creation of detailed bathymetric and seabed classification maps of the area and finally, a risk analysis in terms of erosional phenomena. On the basis of the above, it is concluded that the area under investigation is subjected to an erosional rate of about 1 m/10 years and the total land-loss for the past 70 years is about 4600 m2. Through the simulation of the wave regime we studied 3 possible scenarios, the "do-nothing" scenario, the construction of a detached submerged breakwater at the depth of 3 meters and, finally, the armoring of the existing beach-wall through the placement of appropriate size and material boulders, forming an artificial slope for the reducing of the wave breaking energy and a small scale nourishment plan. As a result, through the modeling of the above, the most appropriate and cost-effective solution was found to be the third, armoring of the existing coastal wall and nourishment of the beach periodically, thus the further undermining of the

  7. Beaches and Dunes of Developed Coasts

    NASA Astrophysics Data System (ADS)

    Nordstrom, Karl F.

    2004-06-01

    This volume discusses the role of humans in transforming the coastal landscape. The book details the many ways beaches and dunes are eliminated, altered and replaced and the differences between natural landforms and the human artefacts that replace them. Emphasis is placed on the importance of retaining naturally functioning beaches and dunes in ways that achieve natural values while accommodating development and use. The issues dealt with in this book will be of interest to practising coastal engineers and research scientists, as well as to planners and managers of coastal resources at all levels of government. It will be of particular value to investigators planning for the future of coastal development under accelerated sea level rise. The book will also be useful as a reference text for graduate and advanced undergraduate courses in geography, geology, ecology and other disciplines dealing with the interaction between science, technology and society.

  8. Sand beach bacteria: enumeration and characterization.

    PubMed

    Khiyama, H M; Makemson, J C

    1973-09-01

    Bacteria in the water-saturated sand of a relatively unpolluted sand beach were enumerated by direct microscope and viable counting. The number of interstitial bacteria was estimated to be a significant fraction of the total number of bacteria present. Three hundred sixty-two strains were isolated and submitted to cultural and biochemical tests. Fermentational abilities and the production of indole suggested that a significant number of these bacteria were symbiotically associated with resident metazoans. PMID:4356458

  9. Sand Beach Bacteria: Enumeration and Characterization

    PubMed Central

    Khiyama, H. M.; Makemson, J. C.

    1973-01-01

    Bacteria in the water-saturated sand of a relatively unpolluted sand beach were enumerated by direct microscope and viable counting. The number of interstitial bacteria was estimated to be a significant fraction of the total number of bacteria present. Three hundred sixty-two strains were isolated and submitted to cultural and biochemical tests. Fermentational abilities and the production of indole suggested that a significant number of these bacteria were symbiotically associated with resident metazoans. PMID:4356458

  10. Assessment of offshore New Jersey sources of Beach replenishment sand by diversified application of geologic and geophysical methods

    USGS Publications Warehouse

    Waldner, J.S.; Hall, D.W.; Uptegrove, J.; Sheridan, R.E.; Ashley, G.M.; Esker, D.

    1999-01-01

    Beach replenishment serves the dual purpose of maintaining a source of tourism and recreation while protecting life and property. For New Jersey, sources for beach sand supply are increasingly found offshore. To meet present and future needs, geologic and geophysical techniques can be used to improve the identification, volume estimation, and determination of suitability, thereby making the mining and managing of this resource more effective. Current research has improved both data collection and interpretation of seismic surveys and vibracore analysis for projects investigating sand ridges offshore of New Jersey. The New Jersey Geological Survey in cooperation with Rutgers University is evaluating the capabilities of digital seismic data (in addition to analog data) to analyze sand ridges. The printing density of analog systems limits the dynamic range to about 24 dB. Digital acquisition systems with dynamic ranges above 100 dB can permit enhanced seismic profiles by trace static correction, deconvolution, automatic gain scaling, horizontal stacking and digital filtering. Problems common to analog data, such as wave-motion effects of surface sources, water-bottom reverberation, and bubble-pulse-width can be addressed by processing. More than 160 line miles of digital high-resolution continuous profiling seismic data have been collected at sand ridges off Avalon, Beach Haven, and Barnegat Inlet. Digital multichannel data collection has recently been employed to map sand resources within the Port of New York/New Jersey expanded dredge-spoil site located 3 mi offshore of Sandy Hook, New Jersey. Multichannel data processing can reduce multiples, improve signal-to-noise calculations, enable source deconvolution, and generate sediment acoustic velocities and acoustic impedance analysis. Synthetic seismograms based on empirical relationships among grain size distribution, density, and velocity from vibracores are used to calculate proxy values for density and velocity

  11. Intensified coastal development behind nourished beaches

    NASA Astrophysics Data System (ADS)

    Armstrong, Scott; Lazarus, Eli; Limber, Patrick; Goldstein, Evan; Thorpe, Curtis; Ballinger, Rhoda

    2016-04-01

    Population density, housing development, and property values in coastal counties along the U.S. Atlantic and Gulf Coasts continue to rise despite increasing hazard from storm impacts. Since the 1970s, beach nourishment, which involves importing sand to deliberately widen an eroding beach, has been the main strategy in the U.S. for protecting coastal properties from erosion and flooding hazards. Paradoxically, investment in hazard protection may intensify development. Here, we examine the housing stock of all existing shorefront single-family homes in Florida - a microcosm of U.S. coastal hazards and development - to quantitatively compare development in nourishing and non-nourishing towns. We find that nourishing towns now account for more than half of Florida's coastline, and that houses in nourishing towns are larger and more numerous. Even as the mean size of single-family homes nationwide has grown steadily since 1970, Florida's shorefront stock has exceeded the national average by 34%, and in nourishing towns by 45%. This emergent disparity between nourishing and non-nourishing towns in Florida demonstrates a pattern of intensifying coastal risk, and is likely representative of a dominant trend in coastal development more generally. These data lend empirical support to the hypothesis that US coastal development and hazard mitigation through beach nourishment have become dynamically coupled.

  12. Textural analysis of Point Calimere beach sand

    NASA Astrophysics Data System (ADS)

    Jeyapal, K. A.

    2013-05-01

    Grain size analysis helps to identify the nature of coastal and sedimentary environments.This parameters provide an insight in to the nature and the energy flux of the transporting agents and their nature of depositional environment. The Beach sediments from the Point Calimere coast are studied for analysis the impact of wave action over the coast. Cauvery and its tributaries are the Chief source for sediments are by the deposits. This dynamic coast of South India is reported to have accretion and erosion at invariably high degrees. Also the impact of land ocean interaction is at high intensity. Further there are chains of Dunes along this coast. The geomorphology of this coast is not a uniform stretch, it has curvature Point Calimere in the south and straight coast towards North. wave properties like reflection, refraction and diffraction are noticed along the study area. Beach Samples were collected along selected zones and their properties were studied in laboratory after sieving half phi interval. Mean mode, sorting, skewness and other statistics are calculated using moment and Folk and Ward graphical methods. This region has three different zones of waves and this wave impact shapes the coast. In few zones erosion were noticed and in few sited deposition Results expressed in metric units, provided of compositionally variable sediments. . The statistical results and field surveys of Point Calimere beach sand samples reveal sediment accretion and wave environments respectivelyGeographic coordinates of sampling stationt; t;

  13. Rescues conducted by surfers on Australian beaches.

    PubMed

    Attard, Anna; Brander, Robert W; Shaw, Wendy S

    2015-09-01

    This study describes the demographics, occurrence, location, primary hazards and outcomes involved in rescues performed by surfers on Australian beaches. Conservative estimates suggest that the number of rescues conducted by Australian surfers each year is on par with the number conducted by volunteer surf lifesavers. Surfers perform a considerable number of serious rescues in both lifesaver/lifeguard patrolled (45%) and unpatrolled (53%) beach locations. Rip currents represent the major physical hazard leading to rescue (75%) and the dominant emotional response of people rescued is one of panic (85%). Most surfer rescue events occur during conditions of moderate waves and sunny, fine weather with the highest proportion of rescues occurring on quiet beaches with few people around (26%). Swimming is the activity associated with most rescue events (63%), followed by board riding (25%). Males aged 18-29 represent the largest demographic of people rescued. Surfers with prior water-safety training are more likely to perform a higher number of rescues, however ability to perform rescues is not associated with formal training, but rather number of years' experience surfing. Seventy-eight percent of surfers were happy to help, while 28% expressed feelings of annoyance or inconvenience, generally towards unwary swimmers. Results of this research suggest that 63% of surfers feel they have saved a life. This value may be enhanced through improved training of surfers in basic water safety rescue techniques. PMID:26056968

  14. Impacts of storm chronology on the morphological changes of the Formby beach and dune system, UK

    NASA Astrophysics Data System (ADS)

    Dissanayake, P.; Brown, J.; Karunarathna, H.

    2015-04-01

    Impacts of storm chronology within a storm cluster on beach/dune erosion are investigated by applying the state-of-the-art numerical model XBeach to the Sefton coast, northwest England. Six temporal storm clusters of different storm chronologies were formulated using three storms observed during the 2013/14 winter. The storm power values of these three events nearly halve from the first to second event and from the second to third event. Cross-shore profile evolution was simulated in response to the tide, surge and wave forcing during these storms. The model was first calibrated against the available post-storm survey profiles. Cumulative impacts of beach/dune erosion during each storm cluster were simulated by using the post-storm profile of an event as the pre-storm profile for each subsequent event. For the largest event the water levels caused noticeable retreat of the dune toe due to the high water elevation. For the other events the greatest evolution occurs over the bar formations (erosion) and within the corresponding troughs (deposition) of the upper beach profile. The sequence of events impacting the size of this ridge-runnel feature is important as it consequently changes the resilience of the system to the most extreme event that causes dune retreat. The highest erosion during each single storm event was always observed when that storm initialised the storm cluster. The most severe storm always resulted in the most erosion during each cluster, no matter when it occurred within the chronology, although the erosion volume due to this storm was reduced when it was not the primary event. The greatest cumulative cluster erosion occurred with increasing storm severity; however, the variability in cumulative cluster impact over a beach/dune cross-section due to storm chronology is minimal. Initial storm impact can act to enhance or reduce the system resilience to subsequent impact, but overall the cumulative impact is controlled by the magnitude and number of

  15. Impacts of storm chronology on the morphological changes of the Formby beach and dune system, UK

    NASA Astrophysics Data System (ADS)

    Dissanayake, P.; Brown, J.; Karunarathna, H.

    2015-07-01

    Impacts of storm chronology within a storm cluster on beach/dune erosion are investigated by applying the state-of-the-art numerical model XBeach to the Sefton coast, northwest England. Six temporal storm clusters of different storm chronologies were formulated using three storms observed during the 2013/2014 winter. The storm power values of these three events nearly halve from the first to second event and from the second to third event. Cross-shore profile evolution was simulated in response to the tide, surge and wave forcing during these storms. The model was first calibrated against the available post-storm survey profiles. Cumulative impacts of beach/dune erosion during each storm cluster were simulated by using the post-storm profile of an event as the pre-storm profile for each subsequent event. For the largest event the water levels caused noticeable retreat of the dune toe due to the high water elevation. For the other events the greatest evolution occurs over the bar formations (erosion) and within the corresponding troughs (deposition) of the upper-beach profile. The sequence of events impacting the size of this ridge-runnel feature is important as it consequently changes the resilience of the system to the most extreme event that causes dune retreat. The highest erosion during each single storm event was always observed when that storm initialised the storm cluster. The most severe storm always resulted in the most erosion during each cluster, no matter when it occurred within the chronology, although the erosion volume due to this storm was reduced when it was not the primary event. The greatest cumulative cluster erosion occurred with increasing storm severity; however, the variability in cumulative cluster impact over a beach/dune cross section due to storm chronology is minimal. Initial storm impact can act to enhance or reduce the system resilience to subsequent impact, but overall the cumulative impact is controlled by the magnitude and number

  16. Shifts in the microbial community composition of Gulf Coast beaches following beach oiling.

    PubMed

    Newton, Ryan J; Huse, Susan M; Morrison, Hilary G; Peake, Colin S; Sogin, Mitchell L; McLellan, Sandra L

    2013-01-01

    Microorganisms associated with coastal sands serve as a natural biofilter, providing essential nutrient recycling in nearshore environments and acting to maintain coastal ecosystem health. Anthropogenic stressors often impact these ecosystems, but little is known about whether these disturbances can be identified through microbial community change. The blowout of the Macondo Prospect reservoir on April 20, 2010, which released oil hydrocarbons into the Gulf of Mexico, presented an opportunity to examine whether microbial community composition might provide a sensitive measure of ecosystem disturbance. Samples were collected on four occasions, beginning in mid-June, during initial beach oiling, until mid-November from surface sand and surf zone waters at seven beaches stretching from Bay St. Louis, MS to St. George Island, FL USA. Oil hydrocarbon measurements and NOAA shoreline assessments indicated little to no impact on the two most eastern beaches (controls). Sequence comparisons of bacterial ribosomal RNA gene hypervariable regions isolated from beach sands located to the east and west of Mobile Bay in Alabama demonstrated that regional drivers account for markedly different bacterial communities. Individual beaches had unique community signatures that persisted over time and exhibited spatial relationships, where community similarity decreased as horizontal distance between samples increased from one to hundreds of meters. In contrast, sequence analyses detected larger temporal and less spatial variation among the water samples. Superimposed upon these beach community distance and time relationships, was increased variability in bacterial community composition from oil hydrocarbon contaminated sands. The increased variability was observed among the core, resident, and transient community members, indicating the occurrence of community-wide impacts rather than solely an overprinting of oil hydrocarbon-degrading bacteria onto otherwise relatively stable sand

  17. 109. VIEW OF SOUTHEAST SIDE OF PIER TAKEN FROM BEACH, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    109. VIEW OF SOUTHEAST SIDE OF PIER TAKEN FROM BEACH, LOOKING WEST. VIEW SHOWS ART DECO BUILDINGS ADDED IN 1931 AND 5TH TEE ADDED IN 1940 Photograph #5369-HB. Photographer unknown, c. 1945, based on clothing of sunbathers; view probably taken in mid-1945 after the U.S. Army vacated the pier and it was reopened to the public. - Huntington Beach Municipal Pier, Pacific Coast Highway at Main Street, Huntington Beach, Orange County, CA

  18. Summer E. coli patterns and responses along 23 Chicago beaches

    USGS Publications Warehouse

    Whitman, R.L.; Nevers, M.B.

    2008-01-01

    Concentrations of E. coli in recreational beach water are highly variable both locally and temporally, but a broader understanding of these fluctuations may be explained through coastal observations. Currently, beach contamination study approaches tend to be site-specific underthe belief that politically delineated beaches are unique and management of beaches cannot be regionally oriented. E. coli data collected over five years from 23 Chicago beaches clearly identified ambient linked patterns at the regional scale. Temporal fluctuations were similar, with all beaches having simultaneous peaks and troughs of E. coli concentrations. Spatially, E. coli concentrations for beaches more closely situated were more closely correlated, indicating spatial autocorrelation. Julian day, wave height, and barometric pressure explained up to 40% of the variation, a value comparable to individual, less parsimonious site-specific models. Day of sampling could explain the majority of the variation in E. coli concentrations, more so than beach, depth, or time of day. Comparing beaches along a targeted coastline allows a better understanding of inherent background regional fluctuations and, ultimately, better predictions of E. coli concentrations in coastal recreational water.

  19. 3. Historic American Buildings Survey Cal State Division Beaches and ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. Historic American Buildings Survey Cal State Division Beaches and Parks Collection Photo 1958 Rephoto 1960 EAST ELEVATION - Adams & Company Building, 1014 Second Street, Sacramento, Sacramento County, CA

  20. Hyperspectral image classifier based on beach spectral feature

    NASA Astrophysics Data System (ADS)

    Liang, Zhang; Lianru, Gao; Bing, Zhang

    2014-03-01

    The seashore, especially coral bank, is sensitive to human activities and environmental changes. A multispectral image, with coarse spectral resolution, is inadaptable for identify subtle spectral distinctions between various beaches. To the contrary, hyperspectral image with narrow and consecutive channels increases our capability to retrieve minor spectral features which is suit for identification and classification of surface materials on the shore. Herein, this paper used airborne hyperspectral data, in addition to ground spectral data to study the beaches in Qingdao. The image data first went through image pretreatment to deal with the disturbance of noise, radiation inconsistence and distortion. In succession, the reflection spectrum, the derivative spectrum and the spectral absorption features of the beach surface were inspected in search of diagnostic features. Hence, spectra indices specific for the unique environment of seashore were developed. According to expert decisions based on image spectrums, the beaches are ultimately classified into sand beach, rock beach, vegetation beach, mud beach, bare land and water. In situ surveying reflection spectrum from GER1500 field spectrometer validated the classification production. In conclusion, the classification approach under expert decision based on feature spectrum is proved to be feasible for beaches.

  1. Shore litter along sandy beaches of the Gulf of Oman.

    PubMed

    Claereboudt, Michel R

    2004-11-01

    Beach debris abundance and weight were estimated from surveys on 11 beaches of the Gulf of Oman along the Omani coast. Debris were collected on two occasions from 100 m transects, sorted and categorized by origin and type. Overall contaminations ranged from 0.43 to 6.01 items m(-1) of beach front on different beaches with a mean value of 1.79+/-1.04 gm(-1) (95% C.I). In terms of weight, contamination levels ranged from 7.8 to 75.44 gm(-1) of beach front with a mean contamination of 27.02+/-14.48 gm(-1) (95% C.I). In terms of numbers of items, plastic debris ranked first on all beaches followed by either wood items or other organic materials such as cigarette butts. Industrial debris remained few on all beaches (<10%). Most debris had a local origin and, in terms of numbers, were associated with beach recreational activities whereas fishing debris represented the largest proportion of the debris in terms of weight. There were notable differences between beaches in the relative abundance of recreation-related and fishing-related debris. PMID:15530520

  2. Changes along a seawall and natural beaches: Fourchon, LA

    USGS Publications Warehouse

    Mossa, Joann; Nakashima, Lindsay D.

    1989-01-01

    This paper compares shoreline and beach morphology changes and responses to storms from 1985 to 1988 along sections of a rapidly eroding coast at the Bayou Lafourche headland, Louisiana. A beach consisting of a cement-filled bag seawall and nourishment was compared with natural beaches to the west and east of the project. Local patterns of beach response could be attributed to several recent processes and historical conditions. Hurricane Gilbert, which made landfall in Mexico, caused about 70% of the sediment loss on both the artificially-stablized and the natural shorelines over this three-year period.

  3. Using a watershed-centric approach to identify potentially impacted beaches

    EPA Science Inventory

    Beaches can be affected by a variety of contaminants. Of particular concern are beaches impacted by human fecal contamination and urban runoff. This poster demonstrates a methodology to identify potentially impacted beaches using Geographic Information Systems (GIS). Since h...

  4. Beyond beach width: Steps toward identifying and integrating ecological envelopes with geomorphic features and datums for sandy beach ecosystems

    NASA Astrophysics Data System (ADS)

    Dugan, Jenifer E.; Hubbard, David M.; Quigley, Brenna J.

    2013-10-01

    Our understanding of ecological responses to climatic and anthropogenic forcing lags far behind that of physical or geomorphic responses for beach ecosystems. Reconciling geomorphic features of beaches with ecological features, such as intertidal zones and mobile biota that are not described by beach width alone, could help address this issue. First, although intertidal zones characterized by distinct groups of mobile burrowing animals are described for beaches, the locations and elevations of these zones do not coincide with standard shoreline datums. Second, intertidal zonation on beaches is extremely dynamic due to the combination of unstable sandy substrate and a highly mobile biota; shifting strongly with tides, waves, storms, and beach conditions. We propose that beach biota use ecological "envelopes" of cross-shore habitat to cope with constantly changing beach conditions. We estimated the extent of these "envelopes" for a variety of taxa on tidal to daily, semi-lunar and seasonal to annual time scales, using literature values on cross-shore animal movements and a field study of the positions of intertidal beds of two species of typical mid and upper shore beach invertebrates. Daily or tidal cross-shore movement varied most (1 m to 100 m) with daily "envelopes" covering 7% to 85% of the available beach width. Semi-lunar movement (12 m) and envelopes (28%) were relatively small, while estimated annual "envelopes" were large, averaging 61% of beach width. The large scope of annual ecological envelopes relative to beach widths reflects how intertidal animals escape seasonally extreme or episodically harsh conditions. Intertidal bed positions of a talitrid amphipod and an opheliid polychaete correlated well with selected beach features in our field study suggesting that incorporation of ecological envelopes in models of shoreline evolution may be feasible. Describing ecological zones in terms of more dynamic shoreline features, such as total water level (TWL

  5. The influence of anthropic actions on the evolution of an urban beach: Case study of Marineta Cassiana beach, Spain.

    PubMed

    Pagán, J I; Aragonés, L; Tenza-Abril, A J; Pallarés, P

    2016-07-15

    Coastal areas have been historically characterized as being a source of wealth. Nowadays, beaches have become more relevant as a place for rest and leisure. This had led to a very high population pressure due to rapid urbanisation processes. The impacts associated with coastal tourism, demand the development of anthropic actions to protect the shoreline. This paper has studied the impacts of these actions on the Marineta Cassiana beach, in Denia, Spain. This particular Mediterranean beach has traditionally suffered a major shoreline regression, and the beach nourishments carried out in the 1980s would not have achieved the reliability desired. This research has analysed the historic evolution of the beach and its environment for a period of 65years (1950-2015). A Geographic Information System (GIS) has been used to integrate and perform a spatial analysis of urban development, soil erosion, stream flow, swell, longshore transport, submerged vegetation species and shoreline evolution. The results show how the anthropic actions have affected the shoreline. After the excessive urban development of the catchments, there is no natural sediment supply to the beach. The change in the typology of the sediment, from pebbles to sand, during the beach nourishments has led to a crucial imbalance in the studied area. Moreover, the beach area gained has disappeared, affecting the Posidonia oceanica meadow, and incrementing the erosion rates. The findings obtained are relevant, not only in the management and maintenance of the beaches, but also, in the decision-making for future nourishments. PMID:27065444

  6. Contextual view of Point Bonita Ridge, showing Bonita Ridge access ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Contextual view of Point Bonita Ridge, showing Bonita Ridge access road retaining wall and location of Signal Corps Radar (S.C.R.) 296 Station 5 Transmitter Building foundation (see stake at center left), camera facing north - Fort Barry, Signal Corps Radar 296, Station 5, Transmitter Building Foundation, Point Bonita, Marin Headlands, Sausalito, Marin County, CA

  7. NOWCASTING AND FORECASTING BEACH BACTERIA CONCENTRATION USING THE EPA VIRTUAL BEACH SOFTWARE

    EPA Science Inventory

    Beaches are subject to closure when bacterial counts exceed water quality criteria. Many authorities base these decisions on sample counts, which typically require a day or more to analyze. Sometimes called the persistence model, because conditions are assumed to persist, experie...

  8. MEETING IN MEXICO: NOWCASTING AND FORECASTING BEACH BACTERIA CONCENTRATION USING EPA'S VIRTUAL BEACH SOFTWARE

    EPA Science Inventory

    Beaches in the United States of (North) America are subject to closure when bacterial counts exceed water quality criteria. Many authorities base these decisions on water samples that typically require at least 18 hours to analyze. This persistence approach, or model, often leads...

  9. Holocene cemented beach deposits in Belize

    NASA Astrophysics Data System (ADS)

    Gischler, Eberhard; Lomando, Anthony J.

    1997-06-01

    Two types of cemented beach deposits occur on reef islands off the coast of Belize. These are (1) intertidal beachrock that is dominantly cemented by marine aragonite and high-magnesium-calcite cements, and (2) supratidal cayrock that is cemented mainly by vadose low-magnesium-calcite cements. Besides differences in position relative to present sea level and resulting early diagenesic features, beachrock and cayrock can be distinguished on the basis of differences in composition, texture, geographical position, and age. Whereas the composition of beachrock is similar to that of the adjacent marginal reef sediments, cayrock is enriched in benthic foraminifera. Intertidal beachrock is moderately to well sorted and well cemented, while supratidal cayrock is very well sorted, poorly cemented and friable. Beachrock occurs preferentially on windward beaches of sand-shingle Gays on the middle and southern barrier reefs and on the isolated platforms Glovers and Lighthouse Reefs. Cayrock only occurs on larger mangrove-sand Gays of the isolated platforms Turneffe Islands, Lighthouse Reef, and the northern barrier reef. 14C-dating of ten whole-rock and mollusk shell samples produced calibrated dates between AD 345 and AD 1435 for beachrock and between BC 1085 and AD 1190 for cayrock. The large-scale distribution of beachrock in Belize supports the contention that physical processes such as water agitation rather than biological processes control beachrock formation and distribution. Only on windward sides of cays that are close to the reef crest, where large amounts of seawater flush the beaches, considerable amounts of cements can be precipitated to produce beachrock. Cayrock forms due to cementation in the vadose zone and is only preserved on larger, stable mangrove-sand cays.

  10. Evaluation of potential sources and transport mechanisms of fecal indicator bacteria to beach water, Murphy Park Beach, Door County, Wisconsin

    USGS Publications Warehouse

    Juckem, Paul F.; Corsi, Steven R.; McDermott, Colleen; Kleinheinz, Gregory; Fogarty, Lisa R.; Haack, Sheridan K.; Johnson, Heather E.

    2013-01-01

    Fecal Indicator Bacteria (FIB) concentrations in beach water have been used for many years as a criterion for closing beaches due to potential health concerns. Yet, current understanding of sources and transport mechanisms that drive FIB occurrence remains insufficient for accurate prediction of closures at many beaches. Murphy Park Beach, a relatively pristine beach on Green Bay in Door County, Wis., was selected for a study to evaluate FIB sources and transport mechanisms. Although the relatively pristine nature of the beach yielded no detection of pathogenic bacterial genes and relatively low FIB concentrations during the study period compared with other Great Lakes Beaches, its selection limited the number of confounding FIB sources and associated transport mechanisms. The primary sources of FIB appear to be internal to the beach rather than external sources such as rivers, storm sewer outfalls, and industrial discharges. Three potential FIB sources were identified: sand, swash-zone groundwater, and Cladophora mats. Modest correlations between FIB concentrations in these potential source reservoirs and FIB concentrations at the beach from the same day illustrate the importance of understanding transport mechanisms between FIB sources and the water column. One likely mechanism for transport and dispersion of FIB from sand and Cladophora sources appears to be agitation of Cladophora mats and erosion of beach sand due to storm activity, as inferred from storm indicators including turbidity, wave height, current speed, wind speed, sky visibility, 24-hour precipitation, and suspended particulate concentration. FIB concentrations in beach water had a statistically significant relation (p-value ‹0.05) with the magnitude of these storm indicators. In addition, transport of FIB in swash-zone groundwater into beach water appears to be driven by groundwater recharge associated with multiday precipitation and corresponding increased swash-zone groundwater discharge at

  11. Geographic setting influences Great Lakes beach microbiological water quality

    USGS Publications Warehouse

    Haack, Sheridan K.; Fogarty, Lisa R.; Stelzer, Erin A.; Fuller, Lori M.; Brennan, Angela K.; Isaacs, Natasha M.; Johnson, Heather E.

    2013-01-01

    Understanding of factors that influence Escherichia coli (EC) and enterococci (ENT) concentrations, pathogen occurrence, and microbial sources at Great Lakes beaches comes largely from individual beach studies. Using 12 representative beaches, we tested enrichment cultures from 273 beach water and 22 tributary samples for EC, ENT, and genes indicating the bacterial pathogens Shiga-toxin producing E. coli (STEC), Shigella spp., Salmonella spp, Campylobacter jejuni/coli, and methicillin-resistant Staphylococcus aureus, and 108–145 samples for Bacteroides human, ruminant, and gull source-marker genes. EC/ENT temporal patterns, general Bacteroides concentration, and pathogen types and occurrence were regionally consistent (up to 40 km), but beach catchment variables (drains/creeks, impervious surface, urban land cover) influenced exceedances of EC/ENT standards and detections of Salmonella and STEC. Pathogen detections were more numerous when the EC/ENT Beach Action Value (but not when the Geometric Mean and Statistical Threshold Value) was exceeded. EC, ENT, and pathogens were not necessarily influenced by the same variables. Multiple Bacteroides sources, varying by date, occurred at every beach. Study of multiple beaches in different geographic settings provided new insights on the contrasting influences of regional and local variables, and a broader-scale perspective, on significance of EC/ENT exceedances, bacterial sources, and pathogen occurrence.

  12. Falcon Beach School Closure Review. Research 87-01.

    ERIC Educational Resources Information Center

    Manitoba Dept. of Education, Winnipeg. Planning and Research Branch.

    Falcon Beach School is a small school experiencing declining school enrollment and increasing operational costs. In February, 1987, Falcon Beach School was announced as a candidate for closure. The Planning and Research Branch of Manitoba Education conducted an economic and social analysis of the school operations. This research report provides…

  13. The Beach--A Natural Protection from the Sea.

    ERIC Educational Resources Information Center

    Sensabaugh, William M.

    1983-01-01

    The beach and sand dunes are the first line of defense protecting the land from the sea. The effectiveness of the beach is caused by its sloping surface which dissipates the energy of waves and by the flexibility of the slope which changes as the waves change. The process and rate of accretion and erosion are dependent on the size and frequency of…

  14. View of the yacht club facing north. The beach is ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of the yacht club facing north. The beach is in the foreground, the pier to the right. The painted octagonal window is above the deck. Avila's Front Street is at the rear of the building. - San Luis Yacht Club, Avila Pier, South of Front Street, Avila Beach, San Luis Obispo County, CA

  15. Dramatic Improvements in Beach Water Quality Following Gull Removal

    EPA Science Inventory

    Gulls are often cited as important contributors of fecal contamination to surface waters, and some recreational beaches have used gull control measures to improve microbial water quality. In this study, gulls were chased from a Lake Michigan beach using specially trained dogs, a...

  16. At Long Beach, Success Is Measured by Degrees

    ERIC Educational Resources Information Center

    Fain, Paul

    2009-01-01

    The California State University campus at Long Beach graduated 8,720 students last month. Each one got the opportunity to walk the stage, and F. King Alexander, the university's president, shook every hand. California State at Long Beach has made graduating a greater number of its 38,000 students its top priority. The slogan "Graduation Begins…

  17. Howard Beach Youth: A Study of Racial and Ethnic Attitudes.

    ERIC Educational Resources Information Center

    Lichter, Linda S.; Lichter, S. Robert

    This assessment of the climate of racial and ethnic attitudes in Howard Beach (New York) was conducted at John Adams High School, the public school attended by the greatest number of high school children in the Howard Beach community. The survey of 1,217 students was administered in December, 1986, several weeks before the incident in which a…

  18. 270. OFFICERS' QUARTERS (FORMER SUMMER COTTAGES) AT DOG PATCH BEACH, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    270. OFFICERS' QUARTERS (FORMER SUMMER COTTAGES) AT DOG PATCH BEACH, C. 1939. VIEW NORTH DOWN GREENWICH ROAD TOWARD FORMER SUMMER COTTAGES, CONVERTED TO OFFICER'S QUARTERS, OVER-LOOKING DOG PATCH BEACH. - Quonset Point Naval Air Station, Roger Williams Way, North Kingstown, Washington County, RI

  19. RECREATIONAL BEACH WATER QUALITY MONITORING WITH QUANTITATIVE POLYMERASE CHAIN

    EPA Science Inventory

    Recreational beaches are an important economic and aesthetic asset to communities, states and the nation as a whole. Considerable resources are expended each year in monitoring the water at these beaches for fecal indicator bacteria as a means of determining if it is safe for pu...

  20. Microfungi diversity isolation from sandy soil of Acapulco touristic beaches

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Microscopic fungi diversity in marine sandy soil habitats is associated with key functions of beach ecosystems. There are few reports on their presence in Mexican beaches. Although standard methods to obtain the fungi from soil samples are established, the aim of this pilot study was to test the pla...

  1. Tracer Studies In Laboratory Beach Simulating Tidal Influences

    EPA Science Inventory

    Bioremediation of oil spills on tidally influenced beaches commonly involves the addition of a nutrient solution to the contaminated region of the beach at low tide to stimulate the growth of indigenous oil-degrading bacteria. Maximizing the residentce time of nutrients in the be...

  2. Virtual Beach v2.2 User Guide

    EPA Science Inventory

    Virtual Beach version 2.2 (VB 2.2) is a decision support tool. It is designed to construct site-specific Multi-Linear Regression (MLR) models to predict pathogen indicator levels (or fecal indicator bacteria, FIB) at recreational beaches. MLR analysis has outperformed persisten...

  3. Bodies that Matter: Performing White Possession on the Beach

    ERIC Educational Resources Information Center

    Moreton-Robinson, Aileen

    2011-01-01

    Beaches remain important places within indigenous coastal peoples' territories, although the silence about our ownership is deafening. Many authors have argued that within Australian popular culture the beach is a key site where racialized and gendered transgressions, fantasies, and desires are played out, but none have elucidated how these…

  4. Composite analysis for Escherichia coli at coastal beaches

    USGS Publications Warehouse

    Bertke, E.E.

    2007-01-01

    At some coastal beaches, concentrations of fecal-indicator bacteria can differ substantially between multiple points at the same beach at the same time. Because of this spatial variability, the recreational water quality at beaches is sometimes determined by stratifying a beach into several areas and collecting a sample from each area to analyze for the concentration of fecal-indicator bacteria. The average concentration of bacteria from those points is often used to compare to the recreational standard for advisory postings. Alternatively, if funds are limited, a single sample is collected to represent the beach. Compositing the samples collected from each section of the beach may yield equally accurate data as averaging concentrations from multiple points, at a reduced cost. In the study described herein, water samples were collected at multiple points from three Lake Erie beaches and analyzed for Escherichia coli on modified mTEC agar (EPA Method 1603). From the multiple-point samples, a composite sample (n = 116) was formed at each beach by combining equal aliquots of well-mixed water from each point. Results from this study indicate that E. coli concentrations from the arithmetic average of multiple-point samples and from composited samples are not significantly different (t = 1.59, p = 0.1139) and yield similar measures of recreational water quality; additionally, composite samples could result in a significant cost savings.

  5. WATER QUALITY ASSESSMENT OF LAKE TEXOMA BEACHES, 1999-2001

    EPA Science Inventory

    A biological and inorganic assessment of five beaches on Lake Texoma was conducted from September 1999 through July 2001. Water samples for each beach site were divided into two groups, a swimming season and non-swimming season. Water properties such as temperature, alkalinity,...

  6. Beach morphology and coastline evolution in the southern Bohai Strait

    NASA Astrophysics Data System (ADS)

    Zhang, Wei; Wu, Jianzheng; Li, Weiran; Zhu, Longhai; Hu, Rijun; Jiang, shenghui; Sun, Yonggen; Wang, Huijuan

    2015-10-01

    The beach studied in this paper spans a length of 51 km and is one of several long sandy beaches in the southern Bohai Strait. Due to the obstruction of islands in the northeast and the influence of the underwater topography, the wave environment in the offshore area is complex; beach types and sediment transport characteristics vary along different coasts. The coastlines extracted from six aerial photographs in different years were compared to demonstrate the evolving features. Seven typical beach profiles were selected to study the lateral beach variation characteristics. Continuous wind and wave observation data from Beihuangcheng ocean station during 2009 were employed for the hindcast of the local wave environment using a regional spectral wave model. Then the results of the wave hindcast were incorporated into the LITDRIFT model to compute the sediment transport rates and directions along the coasts and analyze the longshore sand movement. The results show that the coastline evolution of sand beaches in the southern Bohai Strait has spatial and temporal variations and the coast can be divided into four typical regions. Region (I), the north coast of Qimudao, is a slightly eroded and dissipative beach with a large sediment transport rate; Region (II), the southwest coast of Gangluan Port, is a slightly deposited and dissipative beach with moderate sediment transport rate; Region (III), in the central area, is a beach that is gradually transformed from a slightly eroded dissipative beach to a moderately or slightly strong eroded bar-trough beach from west to east with a relatively moderate sediment transport rate. Region (IV), on the east coast, is a strongly eroded and reflective beach with a weak sediment transport rate. The wave conditions exhibit an increasing trend from west to east in the offshore area. The distribution of the wave-induced current inside the wave breaking region and the littoral sediment transport in the nearshore region exhibit a gradual

  7. Effect of ridge-ridge interactions in crumpled thin sheets

    NASA Astrophysics Data System (ADS)

    Liou, Shiuan-Fan; Lo, Chun-Chao; Chou, Ming-Han; Hsiao, Pai-Yi; Hong, Tzay-Ming

    2014-02-01

    We study whether and how the energy scaling based on the single-ridge approximation is revised in an actual crumpled sheet, namely, in the presence of ridge-ridge interactions. Molecular dynamics simulation is employed for this purpose. In order to improve the data quality, modifications are introduced to the common protocol. As crumpling proceeds, we find that the average storing energy changes from being proportional to one-third of the ridge length to a linear relation, while the ratio of bending and stretching energies decreases from 5 to 2. The discrepancy between previous simulations and experiments on the material-dependence for the power-law exponent is resolved. We further determine the average ridge length to scale as 1/D1/3, the ridge number as D2/3, and the average storing energy per unit ridge length as D0.881 where D denotes the volume density of the crumpled ball. These results are accompanied by experimental proofs and are consistent with mean-field predictions. Finally, we extend the existent simulations to the high-pressure region and verify the existence of a scaling relation that is more general than the familiar power law at covering the whole density range.

  8. Deepwater Horizon oil spill impacts on Alabama beaches

    NASA Astrophysics Data System (ADS)

    Hayworth, J. S.; Clement, T. P.; Valentine, J. F.

    2011-12-01

    From mid June 2010 to early August 2010, the white sandy beaches along Alabama's Gulf coast were inundated with crude oil discharged from the Deepwater Horizon well. The long-term consequences of this environmental catastrophe are still unfolding. Although BP has attempted to clean up some of these beaches, there still exist many unanswered questions regarding the physical, chemical, and ecological state of the oil contaminated beach system. In this paper, we present our understanding of what is known and known to be unknown with regard to the current state of Alabama's beaches in the aftermath of the Deepwater Horizon disaster. Motivated by our observations of the evolving distribution of oil in Alabama's beaches and BP's clean-up activities, we offer our thoughts on the lessons learned from this oil spill disaster.

  9. Deepwater Horizon oil spill impacts on Alabama beaches

    NASA Astrophysics Data System (ADS)

    Hayworth, J. S.; Clement, T. P.; Valentine, J. F.

    2011-07-01

    From mid June 2010 to early August 2010, the white sandy beaches along Alabama's Gulf coast were inundated with crude oil discharged from the Deepwater Horizon well. The long-term consequences of this environmental catastrophe are still unfolding. Although BP has attempted to clean up some of these beaches, there still exist many unanswered questions regarding the physical, chemical, and ecological state of the oil contaminated beach system. In this paper, we present our understanding of what is known and known to be unknown with regard to the current state of Alabama's beaches in the aftermath of the Deepwater Horizon disaster. Motivated by our observations of the evolving distribution of oil in Alabama's beaches and BP's clean-up activities, we offer our thoughts on the lessons learned from this oil spill disaster.

  10. USING TODAY'S DATA TO CLOSE THE BEACH TODAY. QUANTITATIVE POLYMERASE CHAIN REACTION (QPCR) RAPID BEACH CLOSINGS TOOL

    EPA Science Inventory

    Recreational beaches are an important economic and aesthetic asset to communities, states and the nation as a whole. Considerable resources are expended each year in the measurement of fecal indicator bacteria concentrations in the water at these beaches to determine whether thes...