The Suffolk coast around Dunwich and Sizewell has experienced major changes during the past 2000 years, with significant loss of land caused by marine erosion. Against a background of projected acceleration in sea level rise and storminess resulting from global climate change, concern has been expressed that present coastal defences may become unsustainable in the medium to longer term, and that the survival of internationally important wildlife habitats is under threat. This paper examines the past coastal evolution in the light of natural processes, and provides a discussion of future management options. Based on analysis of historical maps, charts, air photographs, and ground survey data, it is shown that rates of coastal erosion have actually been much lower in the last 50 years than historically, and at present there is little scientific evidence to support a case for large-scale managed realignment or abandonment of flood and coastal defences. However, in some areas, notably the very northern end of the Minsmere barrier and the middle part of the Dunwich-Walberswick barrier, local realignment and/or construction of stronger secondary flood defences are required to establish a coastal condition that is more in equilibrium with current processes, and to provide adequate protection against marine flooding even under present climatic and sea level conditions.

Low Isles Reef is the most southerly located of 46 coral reef platforms unique to the inner shelf of the northern Great Barrier Reef Province, Australia, which support both sea grass and mangrove growth. Such reefs develop in areas that are influenced by river flood plumes and where interreef sediments are dominated by terrigenous mud. Low Isles Reef has long been a popular tourist destination. Informal reports of decreasing visibility, a decline in scleractinian corals, and increases in soft coral and macroalgae have sparked speculation that agricultural activities in coastal catchments are affecting the reef. Comparison of the modern surface of Low Isles Reef with historical surveys and photographs dating back to 1928 allows quantification of modern sedimentary processes, rates of change, and factors influencing reef development. Results indicate that changes on Low Isles Reef are related to remobilization of coarse sediment during storm events and gradual shoreline retreat associated with rising sea level. Retreat of shingle ramparts and elongate ridges of coral debris toward the reef interior has led to the infilling of subtidal ponds on the reef top, which supported hard coral colonies in 1928. The gradual development of a composite shingle rampart along the windward margin has promoted an increase (∼150%) in the area of the reef top covered by mangroves. On the leeward margin, a decrease in hard corals since 1950 may reflect a rising contribution of organic debris from the expanding mangrove swamp. Results suggest that recent changes on Low Isles Reef can be explained in the context of natural processes. Further study is needed before the effects of agricultural activities in coastal catchments on reef health can be confirmed.

Sorting of sediment on a beach occurs when the cross-shore profile consists of graded sediments. Each grain-size fraction within a mixture responds differently to the same hydrodynamic regime. Sorting of sediment under wave action takes several forms. Stratified layers of finer and coarser sediment are formed, depending on wave climate, grain size, and beach slope. Grain size and sorting studies are of great importance in characterizing the dynamic beach environment. Some field data have been reported in the literature. In the present study, the cross-shore distribution of sediments, as well as the corresponding beach profiles, were measured in a wave basin on 1:5 beach slope for regular waves. Eighteen sets of experiments were performed on cross-shore sorting mechanisms using two different sand beds.

The sorting of bed material and the formation of armor coats along beach profiles were defined by grain-size distribution and dimensionless parameters in this study. The experiments showed that finer material was deposited on the crest of bar-type beach profiles, but coarser grains accumulated on the foreshore, trough, ridge, and toe sections. Finer materials settled on the foreshore and crest of step-type profiles while coarser grains were deposited on the ridge and toe sections.

The effect of the movement of a particular fraction on the sediment transport rate was also studied. Calculated sediment transport, modified to include the effects of sorting, was compared with transport rates measured in the wave basin. This suggested that the results under the experimental conditions were satisfactory for the description of sediment transport in the surf zone using the partial sediment transport mechanism over the beach profiles.

Surficial sediments from 56 stations on the Orinoco Delta offshore zone were analyzed by x-ray fluorescence spectrometry for aluminum (Al), barium (Ba), calcium (Ca), chromium (Cr), copper (Cu), iron (Fe), hafnium (Hf), magnesium (Mg), manganese (Mn), sodium (Na), nickel (Ni), rubidium (Rb), silicon (Si), strontium (Sr), vanadium (V), zinc (Zn), and zirconium (Zr). The resulting compositional data set was subjected to factorial and cluster analysis. The results demonstrated that two different sedimentary environments could be distinguished: (1) fine-grained sediments with significantly higher concentrations of Al, Cr, Fe, Mn, Rb, V, and Zn, and (2) coarse-grained sediments with significantly higher concentrations of Ca, Hf, Sr, Zr, and Si. On the other hand, Ba, Cu, Mg, Na, and Ni show relatively homogeneous concentrations in the sediments studied.

Our results suggest that the calcareous and coarse-grained quartz sand fringe is a transgressive and relict sediment from the last glacial. This fringe, which is parallel with the coastlines, occurs at between 80 and 170 meters of water depth. Presumably all the studied trace elements, except Sr, Hf, and Zr, are adsorbed on clays and/or are associated with oxide-oxyhydroxides of Fe-Mn. Strontium shows a good correlation with Ca, which suggests the presence of carbonates. The high degree of correlation between Zr and Hf suggests a common origin, probably associated with the presence of heavy minerals.

The concentrations of the trace elements reported in this work are useful as reliable baselines and can be used for comparison in future sediment studies.

Erosion along the West Coast of the United States is affected by climate controls that include a trend of increasing wave heights during at least the past 25 years that might be related to global warming and the El Niño Southern Oscillation (ENSO) range between El Niños and La Niñas that affects both annual wave conditions and monthly mean water levels that raise tidal elevations. These processes are analyzed for sites from Washington to south-central California, revealing a latitude dependence of the individual processes and how their combinations affect total water levels at the shore, which is important to beach and property erosion. Particularly significant on the coast of the Pacific Northwest (Washington and Oregon) has been the progressive decadal increases in deep-water wave heights and periods, which have increased breaker heights and elevated storm wave runup levels on beaches. Along the entire West Coast, the annual variations in wave conditions above and below any progressive decadal increase are controlled by the North Pacific index (NPI), the atmospheric pressure difference between the Hawaiian High and Aleutian Low, and the ENSO range, as demonstrated by a strong correlation with the multivariate ENSO index (MEI), with the highest wave conditions occurring during El Niños. In addition, the ENSO range is particularly important in controlling mean water levels, causing tides to reach their highest elevations during El Niños, again shown by correlations with MEIs along the entire West Coast. With El Niños producing increased deep-water wave heights, runup levels on beaches, and elevated tides, the total water levels at the shore from the combined processes are significantly higher compared with normal or La Niña years, resulting in episodes of major property erosion along the entire US West Coast.

Dredged materials from maintenance and deepening of inlets on coastal barriers are typically transported for disposal in deep water or on land. An alternative is to treat dredged materials as a resource, placing them on the ebb-tidal delta or subtidal shoals at depths where they are retained within the long-shore transport system and can nourish eroding down-drift beaches. Deposition of sediments onto subtidal shoals may, however, bury and selectively kill populations of benthic invertebrates, or indirectly alter assemblages by modifying sediment characteristics. Core sampling of the eastern (control) and western (disturbed) sides of Beaufort Inlet, North Carolina, twice before and once 8 months after a large (660,000 m³) disposal revealed significant coarsening of sediments and associated changes to assemblages of benthic macroinvertebrates in response to the perturbation. Impacts to sediments and macroinverte-brates were closely correlated and, although greatest where sediment was directly deposited, extended over a wider (at least 1 km to the east) area than the deposition. Of the taxa comprising faunal assemblages, spionid polychaetes were most affected by the disposal, declining in abundance. These results, which tie the deposition and dispersal of coarse sediments on an ebb-tidal delta to changes in benthos, imply a biological cost that may be less than that of direct nourishment of biologically productive intertidal beaches.

The greatest change in particle roundness, sphericity, and size in most fluvial systems generally occurs in the initial first few kilometers of sediment transport. Observations in natural settings and laboratory experiments have shown that changes, such as increased grain rounding and decreased size due to particle breakage, wear, and attrition, tend to be progressive along the dispersal path.

In marked contrast, this study records highly variable and poorly developed particle-texture trends downslope along short (<5 km) channels that extend directly from a high-relief carbonate source area down to the shore of Lake Annecy in the western Alps, SE France. The observed inconsistent patterns are measured in both a region-wide analysis using all collected samples and also in a more specific survey of samples in six different channels incised on the steep, topographically irregular mountain flanks that border the lake.

The major factor responsible for the irregular downslope patterns of roundness, sphericity, and size in the Annecy study area is the lateral introduction of sediment into the fluvial channels along dispersal paths. Episodic failure of mechanically unstable sediments and their transport down steep valley walls bring less-abraded sediment of variable shape and size along the dispersal paths. The valley wall sediment influx factor warrants further examination to better interpret sedimentation processes in dissected, high-gradient terrains that border coastal areas.

The western eye-wall of Hurricane Ivan (an upper Category 3 hurricane on the Saffir–Simpson scale) passed approximately 21 km east of Dauphin Island as it made an early morning landfall on September 16, 2004. The island experienced Category 1 hurricane (Saffir–Simpson scale) force winds and large storm waves. Ivan affected Dauphin Island in a variety of ways because of the island's morphology and proximity to nearby submerged and emergent features. The eastern end of the barrier island experienced diminished storm wave energy as a result of an emergent offshore sand island (Pelican-Sand Island), which is a portion of the shallow submerged Mobile Bay ebb-tidal delta. These offshore features absorbed most of the energy from Ivan's storm waves. The western end of the island, a thin and low-lying portion of the barrier island platform, received the full impact of the hurricane. Beach-derived sand was transported northward across this portion of the island by the action of storm waves that washed over it. As a result, a large number of gulf-facing dwellings are left stranded within the swash zone, and several are completely surrounded by water. Further west, the island was breached in several places by storm waves that created large channels. These incised features will likely close within a year under more typical fair-weather conditions. However, the resulting depressions behind the newly formed swash-zone berm will take many years to naturally infill. Beach nourishment will probably be necessary to return a large portion of the developed island to its prehurricane geomorphological setting. Hurricane Ivan revealed the fragile nature and precarious setting that Dauphin Island occupies in the Gulf of Mexico.

The bones and teeth of vertebrates occur on shorelines in quantities sufficient to provide a guide to the range of animals that live both inland and offshore. Burial is necessary for any remains to enter the fossil record and coastal deposits representing intertidal and shallow subtidal environments are potential repositories of this record. A survey of 150 published reports on rocky shores from the Cambrian to the Pleistocene reveals approximately 5% in which vertebrate remains are listed and described. In all cases, the vertebrates involved are marine in habit, but there is no reason to suppose that the remains of land-dwelling vertebrates should be excluded from such deposits. The potential for dinosaur remains to be incorporated in marine coastal deposits is appraised with particular attention to the Upper Cretaceous of Baja California (México) and southern California (U.S.A.). Newly discovered hadrosaur (duckbill) dinosaur bones from the Eréndira area on the Pacific coast of Baja California (México) are described as related to a Late Cretaceous rocky shoreline.

Studies on Holocene sea level change along the coast of northeastern South America can assist in understanding how the region's coastal environments might respond to future sea level change. A freshwater wetland along a wave-dominated pocket bay yielded a 980-cm-long sediment core, which records sediment and vegetation change over the past 7000 years. Above basal sand, peaty mud <450-cm depth is overlain by mangrove peat extending <100 cm and dark, peaty freshwater mud <35 cm. Three radiocarbon dates provide a chronological framework and estimate rates of sedimentation. Loss-onignition analysis shows a shift from basal silicates to organic matter at 4000 YBP that indicates a reduction in marine influences and the establishment of a mangrove habitat. Rhizophora dominates the fossil pollen record. Spores of the tree ferns Cnemidaria and Cyathea indicate an adjacent humid forest whereas Polypodium-type spores and Cyperaceae pollen in the upper part of the core indicate freshwater conditions. The reduction in the sedimentation rate from 1.99 mm y⁻¹ before 4000 YBP to 1.05 mm y⁻¹ after 4000 YBP reflects reduced delivery of external sediments to the wetland and the addition of authocthonous organic matter, whereas the further reduction to 0.61 mm y⁻¹ after 3000 YBP suggests declining rates of peat formation and reduced sediment inputs from the forested watershed. We conclude that the stratigraphy and plant succession was the result of long-term building of a beach ridge. Brackish water peat and then freshwater peat formed behind the bar.

We use Remote Sensing Reflectance (Rrs) measurements from Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) to produce maps of the absorption coefficient, a_ph(λ), by phytoplankton in Great Bay, New Jersey. First, the near-infrared data are used to determine the total scattering coefficient b(λ) for λ > 730 nm at all points of the image. Then, the infrared b(λ) is extended smoothly to the visible region of the spectrum and is in turn used to determine a_d(λ) and a_y(λ), the respective volume absorption coefficient by detritus and colored dissolved organic material (CDOM). The determination of b(λ), a_d(λ), and a_y(λ) allows us to simulate what Rrs(λ) should be in the absence of phytoplankton. Subsequently, the simulated Rrs(λ) without phytoplankton is compared with the measured Rrs(λ) to “black out” the spectrum of a_ph(λ) at any point of the image. By applying this procedure in the form of remote sensing algorithms, we can map out the distribution of a_ph(λ) at any given wavelength over the optically deep sections of coastal waters.

Atmospheric and oceanographic conditions stimulate high productivity of marine organisms in the Gulf of California that are bulk producers of calcium carbonate. Due to prevailing winter winds, north-facing beaches receive vast amounts of shell debris derived from offshore clam banks above the 50-m isobath. As shells undergo mechanical abrasion, the smaller particles of carbonate material are transferred from beaches by the wind and sequestered in coastal dunes. This study reports on two dune fields from the midriff zone of the Gulf. Sieve analysis is used to describe the grain size and sorting characteristics of seven samples from dunes at Cerro El Gallo near Mulegé and 12 samples from dunes farther south near San Nicolás. Dune sediments also were impregnated with epoxy to simulate rock samples from which thin sections were made to determine composition and relative abundances of constituent grains. The dunes at Cerro El Gallo are carbonate poor (5–15%) compared with those near San Nicolás (26–51%) and possible factors contributing to regional variation are explored.

Another part of this study appraises the fecundity necessary to produce any carbonate fraction integrated by coastal dunes from seashells. One of the region's more abundant clams, Megapitaria squalida, was used as a model to estimate the number of individuals of a given size and age class required to generate a cubic meter of pure carbonate sand. Satellite images of the dune fields at El Gallo and San Nicolás were viewed to map surface coverage. With input on the thickness of dune deposits and their composition, it is possible to roughly estimate the number of mature Megapitaria equal to the carbonate fraction of these dunes. The method may be applied to all coastal dunes on the Gulf of California and could be used to assess a part of the region's overall carbon budget heretofore unappreciated.

Coastal sea level measured from tide gauges exhibits coherent variability at interannual and decadal scales. We investigate sea-level variability of large geographic areas using annual mean sea-level values obtained from the longest available records of coastal observations. Eight sea-level regional indices are constructed for the Atlantic and the Pacific Ocean basins. High coherency of sea-level variability at the decadal timescales between different oceanic regions is observed. The role of large-scale atmospheric forcing is then examined by comparison with the El Niño–Southern Oscillation (ENSO) and the North Atlantic Oscillation (NAO). Strong correlation between the NAO and the second empirical orthogonal function (EOF) of the northwest Atlantic data set was observed. The second EOF is also significantly correlated with the latitudinal position of Gulf Stream and the Arctic Oscillation (AO). Sea-level changes in the northeast Atlantic are driven by the NAO. Correlation with the AO was also observed. In the Pacific Ocean, ENSO dominates sea-level variability along the eastern and southwest sides of the basin. ENSO signatures appear also in the southwest Atlantic, indicating teleconnection patterns. It is proposed that ENSO-related variability in this region is forced through the Pacific–South American teleconnection mechanism. The correlation between southwest Atlantic sea level and ENSO increased after 1980. Sea-level variability on decadal scales in the northwest Pacific region is influenced by the Pacific Decadal Oscillation.

A GIS-based method that uses the visibility principle to calculate maximum fetch is presented. The software was programmed in the Arc macro language and implemented with the use of the GRID-based functions of the ArcInfo Workstation GIS. Applying L/4 as the effective wavebase and existing wind statistics, use of the method is exemplified by calculating the yearly resuspension frequency in the North Sea–Baltic Sea transition area.

A cross-shore profile evolution model, Uniform Beach Sediment Transport-Time-Averaged Cross-Shore (UNIBEST-TC), is used in the present study. The model was developed at WL/Delft hydraulic laboratory in the Netherlands and comprises a conglomerate of submodels representing identified processes of cross-shore sediment transport. Validation of UNIBEST-TC was carried out using the collected field data at the Egmond site in the Netherlands and at the Duck site in the US. The model is capable of predicting wave height and wave direction for both sites (Egmond site and Duck site). The prediction of long-shore current is reasonable for the Egmond site, but it is unsatisfactory for the Duck site. The difference between the measured and the predicted values for long-shore current and cross-shore current is partly due to the difference between the measured values, which are at a certain depth, and the predicted values that are depth-averaged velocity. Beside that, the turbulence in the breaker zone leads to errors in the measurements, which could be another factor. It is shown in the present study that on relative small scales, opposite morphological behavior is present. Therefore, morphodynamic profile modeling requires a representative characteristic bottom profile. To achieve a qualitative data for the calibration of the model, it is suggested that field measurements should include error ranges. Furthermore, the effect of small variations of the water depth on the processing of the signals should also be taken into account.

Air entrainment and bubble dispersion were studied systematically at vertical circular plunging jets in freshwater, saltwater, and seawater. Although the inception conditions for air entrainment are identical for all water solutions, experimental results show lesser air entrainment in seawater plunging jets for identical inflow conditions. Comparison between seawater and saltwater results suggest that organic matter and biochemicals harden the induction trumpet at plunge point and diminish air entrapment at impingement in seawater. Froude-similar experiments with different geometric scales show lesser air entrainment for inflow conditions satisfying . The results show that classical dimensional analysis of air entrainment is incomplete, while they would imply scales effects in terms of air entrainment for small laboratory studies with wave height at breaking less than 0.3 m.

A two-dimensional hydrodynamic model is newly developed by solving the nonlinear shallow-water equations. To improve the accuracy of the numerical model, a second-order upwind scheme is employed in discretization of the nonlinear convective terms of the momentum equations. The model developed is first verified by applying to prediction of tidal behaviors. The model is then used to predict sea level change due to major historical typhoons in the Southern coastal zone of the Korean Peninsula. The predicted sea levels are compared to available field measurements. A very reasonable agreement is observed.

Clay mineral analysis was conducted on the fine-grained sediments of a 20-meter core of Late Quaternary deposit in the south-central portion of the modern Changjiang delta plain to understand and characterize paleoenvironmental depositional conditions. Four clay mineral suites (Zones I to IV) were recognized in the core. The lowest level (Zone I, Late Pleistocene) of kaolinite (48%) and illite (45%) is representative of a pedogenic formation of alluvial environment. The next upper suite (Zone II, Early Holocene) of kaolinite (44%) and chlorite (22%) is related to an erosional coastal environment associated with an encroaching sea level. The suite (Zone III, Early to mid-Holocene) overlying Zone II incorporates the addition of smectite (6%), the abundance of which is closely linked to the topographic change and the relative sea level fluctuation in the study area. The uppermost suite (Zone IV, Late Holocene) of illite (53%) and smectite (7%) accumulated during the period of major deltaic progradation and presents a change of sediment source from the more local western highlands to the regional Changjiang River basin. Significant variations in the clay mineral signatures support concepts of morphologic change from a subaerially exposed area to the present depression-centered southern Changjiang delta plain during the Holocene as the delta margin was affected by sea level rise and sediment supply and source.

Forty-nine sediments were sampled along the coast of the Seine bay: 19 from the Port-en-Bessin harbor and 30 from the Bay des Veys. Metallic and polychlorinated biphenyl contaminations were estimated in harbor sediments by their comparison to the OSPAR Convention guidelines. Sediments in Bay des Veys were considered as nonpolluted materials and metal concentrations were chosen as regional reference data to calculate anthropogenic factor and gave human contributions of each metal in harbor sediments. The source of the principal pollutants was principally associated with the careening activities and the use of antifouling paints. A statistical study of data showed strong relationships between metals, organic matter, and fine-grained fraction (<50 μm) of sediments, assuming mobility of metals to water column in case of removal.

The mechanism of the threshold of sediment motion under wave action has been investigated by examining the dynamic forces acting on the sediment particle. The force analysis has led to a range of nondimensional parameters of clear physical significance, which are then applied to the analysis of a range of existing experimental data. The introduction of some new nondimensional parameters has resulted in significant improvement in the definition of the threshold of motion condition. Several empirical equations involving different nondimensional parameters have been derived, providing a mathematical description of the threshold condition of the sediment motion. The accuracy of these empirical equations is examined in the context of scientific and engineering applications and a simple equation is recommended for its accuracy and ease of use.

This article discusses a case study made on research carried out on a currently decaying inner harbor in a Cantabrian estuary (ría) (northern Spain), of which natural shelter conditions had led to the development of an old fishing vessel refuge against extraordinary winds and storms and the subsequent construction of a port. Previous research work has been on-going since 1978, seeking shore protection through simple beach restoration based solely on field observations with purely morphodynamic comprehension aims. The object of this investigation work is to now analyze possible definitive solutions for stabilizing the port's entry channel and maintaining its depth by using not only accumulated field experience but new measurements and numerical models.

The morphological units of an ebb tidal delta were mapped and results used to evaluate the relationship between morphology and hydrodynamics, as part of an investigation into the sedimentation at the Entrance Channel at Tauranga Harbour, New Zealand. Four end-member map units (shell lag, coarse sand, medium sand, and fine sand) were identified from the sidescan sonar imagery, which was verified using seabed sediment samples and SCUBA diver observations. These four units were used in a classification scheme that consisted of 10 composite map units. The use of standardized map units helped to reduce the subjectivity involved in sidescan sonar image interpretation. The mapping scheme was used to assist in the understanding of the impact of capital dredging on the morphological evolution of an ebb tidal delta. Observed morphological changes over the ebb tidal delta were attributed to possible changes in the asymmetry of the vertical tide and residual eddy currents.

A new shape function based on an exponential function and a hyperbolic function is derived to analyze the features of a prominent bar-type profile. The former exponential term represents the trend on the slope of the beach, whereas the latter hyperbolic term accounts for the geometric properties of the longshore bar. The present function provides a general functional form relating various geometric characteristics of a bar-type profile to two well-known dimensionless parameters: the surf zone parameter and the sediment fall velocity. An extensive nonlinear regression analysis was performed on field data as well as laboratory data measured from large wave tanks to test the validity of the present model. The model is capable of presenting the concave and convex features of a bar-type profile with a continuous equation without dividing a beach profile into many portions, which is a method commonly employed by previous studies. On the basis of the analysis, a model for describing the single bar beach profile is proposed.