Sand dunes are found in a variety of shapes in deserts and coasts and also on the planet Mars. The basic mechanisms of dune formation could be incorporated into a continuum saltation model, which successfully reproduced the shape of the barchan dunes and has been also applied to calculate interaction of barchans in a field. We have recently extended our dune model to investigate other dune shapes observed in nature. Here, we present the first numerical simulation of the transformation of barchan dunes, under the influence of vegetation, into parabolic dunes, which appear frequently on coasts. Further, we apply our model to reproduce the shape of barchan dunes observed on Mars, and we find that an interesting property related to the martian saltation is relevant to predict the scale of dunes on Mars. Our model can also reproduce unusual dune shapes of the Martian north polar region, like rounded barchans and elongated linear dunes. Our results support the hypothesis that these dunes are indurated.

Aeolian sand ripples are a common feature on sandy deserts and beaches. Standard aeolian ripples have wavelengths of a few centimeters and amplitudes of a few millimeters. Sometimes, much larger ripples are observed. These are known by different names, such as ridges, granule ripples, gravel ripples, or megaripples. Aeolian megaripples are composed of a mixture of coarse and fine noncohesive material; a bimodal distribution of particle sizes is thought to be necessary for large, ripplelike bed forms to develop. Here, we discuss the extension of a recent model for the dynamics of aeolian megaripples. The model assumes that both the saltation and reptation fluxes are modulated by the emergent bed forms. We present a linear stability analysis of the full model as well as the results of numerical simulations. The modeled megaripples evolve through interactions between ripples of different sizes. The formation of megaripples is therefore another example of a self-organizing geomorphological system.

An analysis of storm-driven sedimentary changes on the shoreface of a low–wave-energy cuspate delta on the southern coast of Spain is examined. Bathymetric surveys, ranging from 1- to 40-m depth, were collected 2 days before and 9 days after a high-magnitude Levante storm. The storm lasted only 36 hours, with peak wind gusts of 100 km/h (28 m/s) and maximum wave heights of 7.4 m. Storms of similar magnitude have only been recorded four times in the last 20 years along this coast. The deltaic nearshore and shoreface was divided into three main morphologic and morphodynamic zones based on process-response mechanisms following the storm event. The eastern section, characterised by a steep and concave shoreface, only had minor erosion and deposition as a result of the storm. The area seaward of the river mouth, an intermediate zone where the coastline changes orientation, is characterised by a widening surf zone and an irregular shoreface out to 10-m depth before dipping steeply to 40-m depth. Poststorm changes along this transitional area resulted in the deposition of a thin veneer of sediment over a 3 km² area from 10- to 40-m depth. The western section, a shallow and wide delta front with a double-bar, a trough, and shore-oblique topography, was modified the most by the storm, with significant upper shoreface erosion and shore-oblique erosional scars in 5–7-m depth. Results of spectral wave modelling of wave-induced force match well with observed morphological change; force is minimal along the east coast, more pronounced along the steep shoreface opposite the river mouth, and at a maximum along the west coast. It is suggested that coastal orientation, shoreface morphology (topography, gradients), and storm parameters (wave and wind direction) generated contrasting wind and wave-induced currents on the delta shoreface, resulting in spatial differences in storm response.

Continental shelf environments along the Florida Atlantic southeast coast offshore Palm Beach County were mapped by interpreting seafloor topography derived from airborne laser bathymetry. The study area covered approximately 270 km² along 75 km of coast, extending from the shore to about 55 m water depth beyond the shelf break to the upper Florida-Hatteras Slope. Forty-two mapping units were used to depict seafloor features that ranged from bedrock outcrops and coral reefs to different types of morphosedimentary bodies. Background theory and protocols of geomorphological symbolization are provided as a rationale for the seafloor mapping. Geomorphological mapping symbols were developed specifically for this project and collected in a symbol library as part of an ArcInfo GIS extension that was used to produce the maps in a GIS environment. Spatial distribution patterns of landform assemblages evident in the color-pattern mapping units permitted regionalization of shelf environments into three primary geomorphological reaches: Reach I, Sand Flats and Karst Topography; Reach II, Sand Flats and Coral Reefs; and Reach III, Sand Flats, Hardgrounds, and Coral Reefs. The main hardbottom mapping units include rock outcrop and subcrop, rock rubble, ridge fields, and structural sand flats. Sandy nontidal morphosedimentary bodies include diabathic channel fields, dune fields, sand flats, and bar and trough systems. Tidal morphosedimentary features include ebb-tidal deltas, sandbars, and lobe bars. Results of this mapping effort showed that it is possible to map marine and drowned terrestrial landforms on the continental shelf as depicted in high-resolution airborne laser bathymetry. Adaptation of existing symbols or development of specialized symbolization was required to show geomorphic units to advantage. These maps, which characterize shelf environments, are contextualized in terms of shapes, forms, materials, and coastal process zones. These types of maps find immediate application in regional and detailed sand searches for beach renourishment, subsea cable and pipeline routes, wave and current modeling studies, and environmental management.

In the present study, a spectral analysis was applied to field data and a numerical model of southeastern Everglades and northeastern Florida Bay that involved computing and comparing the power spectrum of simulated and measured flows at the primary coastal outflow creek. Four dominant power frequencies, corresponding to the S1, S2, M2, and O1 tidal periods, were apparent in the measured outflows. The model seemed to reproduce the magnitudes of the S1 and S2 components better than those of the M2 and O1 components. To determine the cause of the relatively poor representation of the M2 and O1 components, we created a steady-base version of the model by setting the time-varying forcing functions—rainfall, evapotranspiration, wind, and inland and tidal boundary conditions—to averaged values. The steady-base model was then modified to produce multiple simulations with only one time-varying forcing function for each model run. These experimental simulations approximated the individual effects of each forcing function on the system.

The spectral analysis of the experimental simulations indicated that temporal fluctuations in rainfall, evapotranspiration, and inland water level and discharge boundaries have negligible effects on coastal creek flow fluctuations with periods of less than 48 hours. The tidal boundary seems to be the only forcing function inducing the M2 and O1 frequency flow fluctuations in the creek. An analytical formulation was developed, relating the errors induced by the tidal water-level gauge resolution to the errors in the simulated discharge fluctuations at the coastal creek. This formulation yielded a discharge-fluctuation error similar in magnitude to the errors observed when comparing the spectrum of the simulated and measured discharge. The dominant source of error in the simulation of discharge fluctuation magnitude is most likely the resolution of the water-level gauges used to create the model boundary.

The world's sandy beaches, already eroding at rates of concern to coastal managers, are facing a further threat based on predictions of global climate change. Although mean sea level rise has long been recognized as a likely consequence of climate change, it has been suggested that there may also be a change in ocean storminess—that is, the intensity and frequency of storm events. While the effects of a change in wave height can be handled with existing analysis methods, the effects of a change in the rate at which storms arrive are less obvious and harder to predict. As a prelude to model studies investigating coastal response to changes in storminess, it is necessary to have a reliable method for generating storm and wave histories that contain waves that not only conform to known distributions of height and period but that also arrive at the proper rate in time.

In the current work a statistical model of the arrival rate of storms and the wave heights within those storms has been developed. Storminess can be modelled by describing interstorm period, storm duration, the average wave height, and the temporal distribution of storm significant wave heights using methods that have been applied in rainfall modelling. The model has been verified against existing wave climate parameters of wave exceedence and wave persistence, and it has been shown to reproduce these statistics reliably.

Coastal environments might be envisaged as being composed by two interacting subsystems: one natural and the other socioeconomic. This work proposes a system of recreational beaches classification in a rank of four indicators (A for excellent, B for good, C for regular, and D for bad), which can be useful in developing countries, where it is important to promote transfer of scientific information about coastal quality in a simple and useful form and to help identify areas worth preserving and others with potential for more intensive use, provided that the appropriate control is in place. The method analyses 60 parameters grouped into two subsystems (natural and socioeconomic). Each of the 30 natural parameters was assessed based on an attribute scale ranging from the worst (1) to the best (3) quality. For the socioeconomic parameters, only positive or negative categories were attributed. For both subsystems, a scale from 1 (not important) to 3 (very important) was used to indicate the weight of each parameter. The sum of the parameters for each subsystem was used separately to find a score. To classify the beaches, different percentages of the total score were used. The scale ranged from 33 to 100% for the natural subsystem and 0 and 100% for the socioeconomic subsystem. A pilot study was made at nine beach areas (∼500 m each) of three different uses and development levels (overdeveloped, developed, and underdeveloped). The D indicator did not appear in our results. The best indicators occurred at less developed beach areas.

This study explores impacts of off-road vehicles on ghost crab populations as a measure of impact from recreational beach use on two beaches of the Cape Hatteras National Seashore and assesses the effectiveness of several alternatives for the use of off-road vehicles (ORVs) on the beach. Ghost crab population size and density have been used as indicators of the environmental quality of beaches and dunes. Data on the creation of an “ORV corridor” in which ORVs can drive on the landward portion of the berm, but not on the beach crest, indicate that it may be possible to preserve ghost crab populations on the beach while still permitting the use of ORVs. Closing the beach crest 24 hours a day may be the optimal solution for preservation of ghost crab populations. High-energy weather events, however, resulted in larger changes to the population dynamics of the ghost crabs. After storms, ghost crabs were able to (re)inhabit areas where their numbers previously had been reduced by the operation of ORVs. While temporary closures of the beach crest may be used to reduce the short-term impacts of ORVs on ghost crab populations on the outer banks of North Carolina, long-term impacts ultimately are controlled by the strength and frequency of storms that reset the system.

The indentation index, which is the ratio between the real length of a coast and its Euclidean length, is a parameter applied to characterize rock coasts and to study their evolution. Rather than subjectively selecting two or more sectors of a rock coast, the method proposed in this paper considers analyzing the indentation index on the same coastline previously split into several adjacent tracts with equal Euclidean length. By digitizing the coastline in a GIS environment, it becomes possible to test several Euclidean length values on the same coastline, obtaining a different spatial variability of the indentation index with each trial. The best length values that maximize the spatial variability of the indentation index are those that determine an indentation index pattern characterized by high variance and low spatial autocorrelation. The spatial distribution of the indentation index can eventually be analyzed considering known littoral forces acting on the studied coast. When more than one Euclidean length value is found to maximize the variability of indentation index within the same coast, it is likely that there are one or more littoral forces acting or interacting differently at different scales.

This paper surveyed tourist users primarily on Olu Deniz beach, Turkey. The majority (70%) were British who used the beach for both recreation activity and to enjoy open space and scenery. Major dislikes were found to be litter (41%), water quality (31%), and dogs' faeces (24%). A positive willingness to pay (WTP) was expressed by 87% of British respondents. British tourists expressing a WTP were prepared to pay £1.03 per adult per visit, giving a mean of £0.90 for the whole sample. Diminishing marginal utility is apparent in the WTP valuation with increased use of the beach. WTP valuation also varies significantly with beach rating. Variables found not to be significant in predicting WTP were: age, gender, income levels, social class, and the contribution the beach experience made to the enjoyment of the total holiday. The WTP valuations given by respondentstended to be round numbers, which may not be full market valuations but do represent revenue raising opportunities for coastal zone managers. The vehicle of payment selected by 72% of respondents was “adults paying per visit.” Nearly all (99%) the respondents thought that children should not pay any contribution. The consumer surplus for enjoying the beach was £1.11 per adult per visit. Understanding tourists' values and acting in accordance with them may be paramount for the successful introduction of tourist ecotaxes. The reported reduction in visitors to the Balearic Islands (10%) following the imposition of a tourist ecotax of circa € 1 per person per day is similar to the proportion of respondents who were not willing to pay to maintain or improve the beach. This reduction in demand may reflect a refusal to pay tourism ecotaxes on principle or a simple market reaction to an increased price or charge.

This paper presents a wave measurement technique based on single-video monitoring of moored buoys. A simple photogrammetry is proposed, with a constraint that the distance from video camera to buoy should be predetermined. The distance is approximated to a constant under the condition that it is much greater than the range of the buoy motion. Image coordinates of a buoy are mapped onto a spherical surface without significant errors in vertical ground coordinates. Wave characteristics are comparable to those from a bottom pressure gauge, indicating that the video technique has the potential to remotely measure waves in coastal environments. We anticipate our finding to be a starting point for an economic instrument of wave measurement through development of an automated image processing technique.

The sediment distribution in the southern Bay of Campeche is mainly governed by wind-induced currents and mesoscale cyclonic eddies. An increase in sediment grain size toward the sea is attributed to the presence of a convergence zone that sorts the sediments from heavier to lighter. A small anticyclonic eddy near the coast leads to a concentration of sediments westward of the Grijalva-Usumacinta River. We combined current profiles and charts of the distribution of magnetic susceptibility within sediments with a hydrodynamic numerical model to elucidate the distribution of the major sedimentary units in the Southern Bay of Campeche, Gulf of Mexico. Acoustic Doppler current profiles and geostrophic velocity data were used to set the water velocity at the open boundaries of the applied numerical model. The model was forced by the dominant winds. Sediment on the southeastern side of the bay is dominated by carbonates because of a lack of river discharge and other systems that contribute terrigenous sediments. In the southernmost side of the bay, where the major rivers are located, the bottom sediments are mainly of terrigenous origin.

Sediment cores (up to 6 m in length) from the bottom of the Blue Hole, a 125 m deep Pleistocene sinkhole located in the lagoon of Lighthouse Reef Atoll, Belize, consist of undisturbed, annually layered biogenic carbonate muds and silts with intercalated coarser grained storm beds. The sedimentation rate of the layered sections is 2.5 mm/y on average, and the long cores span the past 1500 years. Oxygen isotopes of laminated sediment provide a late Holocene climate proxy: A high-resolution δ¹⁸O time series traces the final Migration Period Pessimum, the Medieval Warm Period, the Little Ice Age, and the subsequent temperature rise. Carbon isotopes (δ¹³C) decrease up core and show the impacts of the decline of the Mayan culture and the Suess effect. Time series analyses of δ¹⁸O and δ¹³C content reveal 88-, 60-, 52-, and 32-year cyclicities, and suggest solar forcing. Storm event beds are most common during AD 650–850, around AD 1000, during AD 1200–1300, and AD 1450–1550. Major storm beds are rare during the past 500 years BP.

The implantation of a submarine outfall pipe in 1995 for the cellulose pulp and paper companies Celbi and Soporcel, Portugal, led to some changes in the Leirosa sand dunes system. The use of heavy machinery and the close proximity of a breakwater aggravated the long-term problems of erosion in this coastal ecosystem.

Sand accretion was the first step in the reconstruction of the Leirosa dunes. Subsequently, to stabilize the sand, we carried out revegetation, planting the grass Ammophila arenaria (L.) Link.

In February 2001, after a particularly severe winter, most of the ocean-facing side of the Leirosa rehabilitated sand dune system was severely damaged. In spite of this problem, the monitoring plan to assess sand erosion and vegetation growth continued.

In 2005, after balancing several alternatives, the Leirosa sand dunes were reconstructed with layers of geotextiles filled with sand. Once the sand containers were in place, this protective barrier was covered with sand and planted with A. arenaria, turning this area into an attractive and safe coastal dune system.

In March 2006, some problems occurred, probably caused by poor sealing of the geotextiles layers, which led to parts of the three bottom layers breaking open. To stabilize and reinforce the sand dune in this specific weakened area, we are currently analysing the use of geotextile tubes.

The attempts to promote the sustainable rehabilitation of a dune system and the implied problems related to its location on a particularly harsh Atlantic coast are discussed in the paper.

The highly dynamic nature of some sandy shores with continuous morphological changes require the development of efficient and accurate methodological strategies for coastal hazard assessment and morphodynamic characterisation. During the past decades, the general methodological approach for the establishment of coastal monitoring programmes was based on photogrammetry or classical geodetic techniques. With the advent of new geodetic techniques, space-based and airborne-based, new methodologies were introduced in coastal monitoring programmes. This paper describes the development of a monitoring prototype that is based on the use of global positioning system (GPS). The prototype has a GPS multiantenna mounted on a fast surveying platform, a land vehicle appropriate for driving in the sand (four-wheel quad). This system was conceived to perform a network of shore profiles in sandy shores stretches (subaerial beach) that extend for several kilometres from which high-precision digital elevation models can be generated. An analysis of the accuracy and precision of some differential GPS kinematic methodologies is presented. The development of an adequate survey methodology is the first step in morphodynamic shore characterisation or in coastal hazard assessment. The sample method and the computational interpolation procedures are important steps for producing reliable three-dimensional surface maps that are real as possible. The quality of several interpolation methods used to generate grids was tested in areas where there were data gaps. The results obtained allow us to conclude that with the developed survey methodology, it is possible to survey sandy shores stretches, under spatial scales of kilometres, with a vertical accuracy of greater than 0.10 m in the final digital elevation models.

A slotted breakwater is a kind of perforated breakwater with vertical slots in the front wall of the structure. It can provide a sheltered area for loading and unloading of ships and crafts. In this study, a modified model to the one proposed by Suh et al. (2001) was developed to calculate the frequency-averaged reflection coefficient by means of the velocity potential. Using this model, the reflected energy spectrum from slotted breakwaters for normal incident waves can be calculated. A comparison with experimental and analytical works shows that this model can accurately predict frequency-averaged reflection from this type of breakwater. This model can provide a good trend to predict frequency-averaged reflection and is a powerful tool for predicting the reflected energy spectrum from slotted breakwaters. The effect of effective parameters such as relative wave chamber width, relative significant wave height, significant wave period, and porosity of the slotted wall was also considered on the frequency-averaged reflection and reflected energy spectrum in this model. One of the most important results is the calculation of frequencies in the reflected spectrum that have a minimum energy close to zero, denoted as zeroth frequency points. This means that a large part of the wave energy in such frequencies is absorbed by the structure of the breakwater.

The formation of rhythmic patterns at the Field Research Facility (U.S. Army Corps of Engineers, Duck, North Carolina) under extreme wave climatic conditions is analyzed in terms of the partial standing oscillations formed by the superposition of the incident edge wave and the wave reflected by the structure. The reflection coefficient at the pier is evaluated with an existing model used for the propagation of an edge wave through a permeable structure perpendicular to the coastline, modified here to deal with an arbitrary beach profile. The mass transport patterns under the partial standing edge waves are found to resemble the beach cusps and the crescentic bars observed on the shore, north of the pier, after a series of storm events.

Coastal landscapes are in a constant state of flux and continue to change with sea level rise. Past trends in land cover may be useful for predicting future landscapes under different scenarios of change. In this study, models representing land-cover change were created for a coastal forest–open water transition in a rapidly subsiding region in the Mississippi Delta, U.S.A. Land-cover images manually delineated from aerial photography for 1940, 1953, 1978, 1998, and 2004 served as the basis for the models. A combination of Markov chain analysis, a cellular automaton, and suitability images were used to model past trends and to create future land-cover scenarios. Model validation revealed that one of two model runs more closely matched reference images than null (no change) models. Models were generally better at predicting the location of land-cover classes on the landscape than the quantity of each class. Prediction accuracy varied among individual land-cover classes, with forest being the most stable and predictable, and scrub-shrub being the least stable and predictable. Future projections offered a range of outcomes and suggest that coastal stability structures are at least initially effective in promoting marsh replacement of open water. Without management intervention, our models predict dramatic loss of marsh and an increasing interface between water and the relatively resistant forest. These models can be helpful in examining responses of coastal transitions to sea level rise and evaluating the effectiveness of management efforts.

Since the completion of a 398,000 m³ nourishment project along 2 km of Rehoboth Beach, Delaware, in August 2005, the subaerial volume and area of the northern 25% of the beach has been monitored monthly through the use of terrestrial-based light detection and ranging (LIDAR) surveys. Traditionally, the Delaware Department of Natural Resources and Environmental Control and the U.S. Army Corps of Engineers use analyses of beach width from aerial imagery and volumes estimated from widely spaced profile surveys to assess nourishment performance and assist in determining renourishment quantities. However, these survey methods lack the spatial and temporal resolution needed for short-term management strategies. Recent efforts at monitoring Atlantic Coast beaches using airborne LIDAR show the potential of this technology for providing more detailed representations of beach volumetric change over time, but the operational costs still limit the frequency of surveys. Alternatively, our terrestrial LIDAR study allows for the development of models of subaerial beach topography with both high temporal and spatial resolution. Although geographically less extensive than airborne surveys, the digital elevation models from our data (1) allow for a better understanding of the range in variation in beach area and volume, especially that due to storm events, (2) provide more accurate volume estimates than traditional profile surveys by as much as 8%, and (3) indicate that the area and volume do not covary, limiting the usefulness of using aerial imagery in estimating volume.

Sea level rise has been identified as a possible factor contributing to marsh loss in Jamaica Bay, New York. However, Jamaica Bay has also experienced increases in tidal ranges throughout as a consequence of natural and engineering modifications that occurred in the bay during the first half of the twentieth century. The increases in the elevations of high tides are of the same order as the increase in regional sea level that occurred since the early 1900s. Marsh inundation in the bay is thus greater than noted to date and greater than that in adjacent bays where tidal ranges have been more stable. Changes in tidal hydrodynamics may be one more factor to consider in the list of potential causes of marsh loss in Jamaica Bay.

We evaluated habitat conditions available to infauna and epifauna across a gradient of shoreline development within the Pascagoula River estuary, Missisippi, to determine whether habitat characteristics and biotic responses were influenced by the degree of surrounding alteration. Three zones were defined: (H) severe alteration, (M) intermediate alteration, and (L) natural conditions starting about 5 km upstream. Eleven water-quality and habitat variables were quantified for infaunal and epifaunal nekton as indicators of habitat quality adjacent to both “restricted” and hardened shore and “unrestricted” or marsh-edge shore within each impact zone. Epifaunal nekton richness (S) was consistently greater at unrestricted shore types than restricted ones, highest in zone M and lowest in zone H, whereas infaunal S did not vary among impact zones or between shore types. Cluster analysis showed epifaunal nekton assemblages from unrestricted shores in zones M and L were most similar to each other, whereas restricted shore infaunal assemblages from zones H and M linked at ∼70%. SIMPER analysis indicated infaunal composition was not dissimilar among zones or between shore types. In contrast, epifaunal nekton assemblages were dissimilar from one another because of the presence and density of Corophium louisianum and Hargeria rapax, two major fish prey items. Our data suggest the relative quality of marsh-edge habitat depends upon the surrounding landscape and that the simple presence of marsh habitat is not enough to ensure a high level of ecosystem health. Rather, it is the spatial arrangement of the marsh that markedly affects the system's health. It is apparent that even the smallest patch of marsh habitat supported a larger diversity of fauna than nearby restricted habitats, suggesting that it matters where a salt-marsh habitat patch (including restoration sites) is located along the landscape because it will influence habitat quality and connectivity and thus the composition of infauna and epifauna nekton assemblages.

QuickBird false color satellite imagery was evaluated for distinguishing black mangrove [Avicennia germinans (L.) L.] populations on the south Texas Gulf Coast. The imagery had three bands (green, red, and near-infrared) and contained 11-bit data. Two subsets of the satellite image were extracted and used as test sites. Supervised and unsupervised image analysis techniques were used to classify the imagery. For the supervised classification of site 1, black mangrove had a producer's accuracy of 82.1% and a user's accuracy of 95.8%, whereas for the unsupervised classification, black mangrove had a producer's accuracy of 100% and a user's accuracy of 60.9%. In the supervised classification of site 2, black mangrove had a producer's accuracy of 91.7% and a user's accuracy of 100%, whereas in the unsupervised classification, black mangrove had a producer's accuracy of 100% and a user's accuracy of 85.7%. These results indicate that QuickBird imagery combined with image analysis techniques can be used successfully to distinguish and map black mangrove along the south Texas Gulf Coast.

Barrier-island chains worldwide are undergoing substantial changes, and their futures remain uncertain. An historical analysis of a barrier-island chain in the north-central Gulf of Mexico shows that the Mississippi barriers are undergoing rapid systematic land loss and translocation associated with: (1) unequal lateral transfer of sand related to greater updrift erosion compared to downdrift deposition; (2) barrier narrowing resulting from simultaneous erosion of shores along the Gulf and Mississippi Sound; and (3) barrier segmentation related to storm breaching. Dauphin Island, Alabama, is also losing land for some of the same reasons as it gradually migrates landward. The principal causes of land loss are frequent intense storms, a relative rise in sea level, and a sediment-budget deficit. Considering the predicted trends for storms and sea level related to global warming, it is certain that the Mississippi-Alabama (MS-AL) barrier islands will continue to lose land area at a rapid rate unless the trend of at least one causal factor reverses. Historical land-loss trends and engineering records show that progressive increases in land-loss rate correlate with nearly simultaneous deepening of channels dredged across the outer bars of the three tidal inlets maintained for deep-draft shipping. This correlation indicates that channel-maintenance activities along the MS-AL barriers have impacted the sediment budget by disrupting the alongshore sediment transport system and progressively reducing sand supply. Direct management of this causal factor can be accomplished by strategically placing dredged sediment where adjacent barrier-island shores will receive it for island nourishment and rebuilding.

Hurricane Katrina made its final landfall on August 29, 2005, as a category three storm, at the mouth of the Pearl River on the Mississippi/Louisiana border. Between October and December of 2005, 16 cores were recovered along two transects in the Pearl River Marsh: one running east to west across the mouth of the delta, and the other running south to north through the center of the basin. Loss-on-ignition and grain-size analysis clearly identified the sediments deposited by the storm and the resulting 5.9 m storm surge. The inorganic storm layer consisted of fine grain sands and silts, which were easily distinguished from the organic peat that develops naturally in the marsh. Although the Pearl River Marsh received uniform storm surge, the storm layer was unevenly distributed and was thicker and more pronounced toward the center of the marsh. The funneling of the storm surge by the floodplain terraces and/or the winnowing effect of wave action could account for this variability. Only 5 of the 16 cores showed evidence of Hurricane Camille, which made landfall near the Pearl River Marsh, as a category five storm, in 1969. Erosion and bioturbation of the marsh sediments could have worked to blur or even erase this layer in some locations, which would explain the inconsistent record. If this level of variability and degradation is common for marsh environments, it presents a challenge to paleotempestological investigations from these areas and emphasizes the importance of environmental reconstructions based on multiple transects of cores.

The December 26, 2004, disastrous tsunami event in the Indian Ocean may have come as a shock and even a surprise to the communities outside geosciences. However, tsunami events are a natural part of the geosystems in regions of submarine earthquakes, and they will continue to hit the region even in the future. Here we present evidence of former tsunami events both on Sri Lanka and on the Maldives. Submarine “sandstorms” driven by tsunami waves brought littoral deposits down into caves 21 to 38 m below sea level. Radiocarbon dates allow the comparison with related tsunami signals in fens and lagoons, and historical documentation. The terrible December 26 event has raised a general awareness of tsunami events. It has also generated the installation of necessary warning systems. We are in urgent need, however, of a long-term tsunami chronology for a realistic tsunami hazards assessment.

Images from an Argus beach monitoring station were analyzed to count the number of people on two city beaches in Barcelona (NW Mediterranean) every hour for 4 years. Daily, weekly, seasonal, and interannual user distribution patterns were clearly established. Two different fit models were applied to the data based on a Fourier polynomial and nonlinear criteria, including external factors such as temperature and wind conditions, as well as predisposition factors. Finally, the evolution of beach users was compared with morphological beach changes caused by natural processes and human action. The results demonstrated that video observations provide a suitable method for counting people on the beach that could be useful for a number of coastal management applications.