This pilot study describes an analysis of the erosion processes of the Bang Khun Thien mangrove mud coast situated at the Upper Gulf of Thailand, and discusses measures to stop this erosion process and to rehabilitate the area. The rapid erosion observed is the result of the decimation in intertidal area by the dikes directly behind the coastline, constructed to protect the fish and shrimp ponds in the coastal area. The decrease in sediment yield from the Chao Phraya River as a result of the construction of the Bhumipol and Sirikit dams, and the local subsidence due to ground water withdrawal and natural settling will augment the observed coastal erosion, but at a much smaller rate. The latter effects are expected to become important on a time scale of about a hundred years only.

The key to stop the erosion processes and rehabilitate the area is therefore the restoration of the intertidal area. This can be done either entirely within the current coastline, but by sacrificing part of the fish and shrimp ponds, or partly within the current coastline and partly in the coastal zone, i.e. in the coastal area recently lost. In the latter case, the coastal area has to be protected from lateral transport of sediment by permeable groynes perpendicular to the coast. It is estimated that an intertidal mangrove belt of about 300 to 500 m is required to re-initiate sedimentation processes, hence to restore a favourable habitat for mangrove forest.

Coastal dune fields commonly occur along the shoreline of Lake Michigan. This study focuses on the geomorphic history of dunes at Petoskey State Park in northern lower Michigan. Results from this study revealed that 5 distinctive geomorphic units occur in the park: a lake terrace, parabolic dunes, linear and incipient parabolic dunes, and active dunes. Samples for optically stimulated luminescence (OSL) and radiocarbon dating were collected throughout the park and suggested that eolian activity began around 4800 cal. yr B.P. and has continued until the present time. In general, the dunes are progressively younger and smaller towards the shoreline. Intensive shoreline progradation and significant vertical aggradation of sand dunes has occurred at Petoskey State Park throughout the Middle and Late Holocene in association with fluctuations of the level of Lake Michigan.

Aeolian transport rates were measured for six months (March–September 1999) at paired scraped and natural shorelines on Bogue Banks, North Carolina. Although wave action was principally responsible for dune volume losses at scraped shorelines, substantial aeolian losses were observed. Beach scraping induced rapid onshore aeolian sediment movement by increasing sediment availability, altering dune morphology, denuding dune foreslopes and modifying dune sediment characteristics. In response to prevailing onshore winds, net transport of sediments across the foredune crest was 1.54 × 10⁻³ m³/m/day, resulting in dune growth at scraped locations. Dune planting with American beach-grass (Ammophila breviligulata) did not substantially reduce aeolian transport rates at a scraped beachfront. Minimization of aeolian losses at scraped dunes by installation of sand fencing is desirable from a management perspective. Accelerated dune migration and depletion of the longshore sediment budget are potential long-term effects of scraping-induced onshore sediment flux on Bogue Banks.

The coastal environment has changed in the past 25 years relation to the industrial and human settlement around the Tuzla Lake, Istanbul, Turkey. At first, the inlet of the Tuzla Lagoon Lake was filled and isolated from the sea, and changed to a fresh water lake. This was followed by chanelling of dirty creeks and a tunnel construction 8 m below the sea level just behind the lake. These engineering constructions resulted in a 3 m fall of ground water level in 4 years around the lake and, as a result a drought occurred in June, 2001. During this period, salty water encroachment and groundwater saltation occurred and farmlands faced significant irrigation problems. After the drought, two connection pipe lines were constructed between the sea and the lake. However, these pipes were filled by sea originated material, mostly shells, within a year and water exchange between the lake and the sea became impossible. As a result, environmental equilibrium has been disturbed and farming habits have changed.

The investigations on the lake mud after the drought reveal that sedimentation rate has been about 1cm/year for past 25 years. A bed rich in shrimp skeletons observed within the lake mud indicates significant pollutant introduction into the lake from industrial or agricultural activities.

Three Holocene tsunami events that struck the islands of Aruba, Curaçao, and Bonaire around 450–500 YBP, 1,500 YBP, and 3,500 YBP resulted in extensive deposits of coarse sediments and boulders along the coastal zone. The tsunami waves approached the islands from an easterly direction. We investigated paleo-tsunami imprints on the islands of Grenada, St. Lucia, and Guadeloupe to locate the source area of those three events. However, along the Caribbean coastlines of the islands, no evidence for Holocene tsunami impacts have been found. Instead, tsunami relics of Middle Pleistocene age are incorporated into tephra depositions of these volcanic islands. At least one Holocene tsunami event is preserved in the form of bimodal accumulations and boulder deposits along the east coast of Guadeloupe, indicating that the tsunami hit the island from the open Atlantic ocean. Radiocarbon dating yielded an age of about 2,400–2,700 years YBP for the event.

Dinkum Sands was mapped in 1949 as a small island, one link in a 95-km-long chain of barrier islands near Prudhoe Bay, Alaska. Questions about its status as an Arctic island and the submerged land ownership led to a Federal/State joint monitoring program using topographic surveys, tide gauges, and other approaches. On the basis of the results the Supreme Court concluded that Dinkum Sands is a shoal rather than an island. The shoal attracts the yearly formation of pressure ridges at least as high as 15 m and undergoes drastic changes in location, shape, and elevation. Pressure ridges form from 10-cm-thick new ice when shifting and compression result in crumbling and the introduction of ice slabs into the sandy gravel shoal. This leads to a seasonal increase in shoal volume and height. With summer warming and sea-ice melting, part of the ice in the crest of the shoal (∼50%) melts and its height accordingly drops to below sea level. This lowering requires neither wave action nor lateral sediment transport. The original disappearance of the island in the 1950s, however, probably was not caused by diminished sediment supply from rivers or from coastal erosion, but by diminished local sediment supply through ice pile-ups or by increased erosion from wave attack. Similar changes in sediment volume as those observed in Dinkum Sands probably also occur on fully submerged shoals ranging to water depths of 20 or more meters, which are also marked by seasonal pressure ridge formation.

This paper focuses on relationships between the North Atlantic Oscillation (NAO) Index in selected months and periods and the ice conditions along the southern coast of the Baltic Sea. The data on ice conditions, including the number of days with ice (L) and the length of ice season (counted in days; S), cover 25 observation regions located between Arkona in the West and Kaliningrad in the East for winters of the 1950/51–1989/90 period. The NAO Index, understood to be the difference between normalized values of atmospheric pressure in Gibraltar and Reykjavik, was applied.

Correlation and regression analysis methods were applied to determine and study the relationships between NAO (independent variable) and the parameters of ice conditions L and S (dependent variables). The linear relationships recorded for sheltered basins (Szczecin Lagoon, Puck Bay Small, Vistula Lagoon) were stronger than those calculated for unsheltered ones (e.g., open Baltic Sea coast). The majority of relationships of ice conditions (L and S) to winter monthly NAO values, particularly for January (NAO_II) and February (NAO_II) in sheltered basins, are statistically significant, some of them even at the level of α = 0.01. The linear correlation coefficients, in most cases, were included within the range from −0.3 to −0.7. The strongest of them were calculated for January and February and encompassed the range from −0.5 to −0.7. The strength of these relationships tended to increase when particular months were connected into several-month periods of NAO Index, especially during the January–March and December–March periods. During these periods the correlation coefficients were usually in the −0.7 to −0.8 interval. In addition, the relationships of the NAO index with L were distinctly stronger than those with S. The strongest relationships, with linear correlation coefficients exceeding −0.80, were obtained for the number of days with ice (L) in protected areas, e.g., in Vistula Lagoon for a period of December–March (NAO_XII–III) and in Puck Bay for January–March period (NAO_I–III). These relationships are weaker in unsheltered areas, where the correlation coefficient does not exceed the value of −0.75. The strongest of them concern the estuarine regions of large rivers (Dziwnów, Świbno) and bays (Mie dzyzdroje), whereas the relationships between the NAO Index and L and S did not differ significantly from each other in unsheltered basins. However, for the NAO periods of December–March and January–March, they were stronger with S than with L.

The correlation coefficients show a decreasing tendency eastward along the southern Baltic Sea coast from Pomeranian Bay to Gdańsk Bay (northward of the Hel Peninsula). They become stronger in the western part of the Gulf of Gdańsk and in the mouth of the Vistula and again decrease eastward.

During some extremely severe or very mild winters, the extreme ice conditions do not always match the extreme NAO index values. During extremely severe winters, the ice cover could exist for a relatively long period, which is a result not only of the high inertia of thick ice covers but also of high cloudiness restricting the impact of insolation. However, during extremely mild winters, ice can disappear relatively quickly (thin covers, low cloudiness), comparable to the NAO index values.

A high-resolution pollen study (136 samples) has been performed on the KTR05 core (738 cm long) located in the modern Grand Rhône prodelta. The objectives were (1) to evaluate the palynological and sedimentological record quality of a prodelta in comparison with fluvial inputs (2) and to quantify lost sediment (resuspensions) in this area. The core covers more than the last thirty years. By comparison with the modern pollen rain both in the Rhône delta and in the mid-drainage basin (Lyon), a seasonal forcing in pollen deposition has been demonstrated. Monthly pollen successions can be evidenced in a well preserved sequence, providing an estimate of the true sedimentation rate (60 cm.yr⁻¹). Importance of disturbed or incomplete sequences suggests that most of the sediment first deposited in the prodelta (around ⅔) has been resuspended. Sedimentological and palynological data record not only seasonal but fluvial impact. The progressive shift of the prodelta has been evidenced firstly with sedimentology and secondly with palynology. Despite high fluvial impact, pollen grains in the KTR05 core are representatives of the vegetation of the Rhône drainage basin. The apparent homogeneity of the pollen spectra evidences the high reliability of palynology applied on prodeltaic area, at least in a microtidal environment.

The sediment budget is fundamental in coastal science and engineering. Budgets allow estimates to be made of the volume or volume rate of sediment entering and exiting a defined region of the coast and the surplus or deficit remaining in that region. Sediment budgets have been regularly employed with variations in approaches to determine the sources and sinks through application of the primary conservation of mass equation. Historically, sediment budgets have been constructed and displayed on paper or maps. Challenges in constructing a sediment budget include determining the appropriate boundaries of the budget and interior cells; defining the possible range of sediment transport pathways, and the relative magnitude of each; representing the uncertainty associated with values and assumptions in the budget; and testing the sensitivity of the series of budgets to variations in the unknown and temporally-changing values. These challenges are usually addressed by representing a series of budget alternatives that are ultimately drawn on paper, maps, or graphs. Applications of the methodology include detailed local-scale sediment budgets, such as for an inlet or beach fill project, and large-scale sediment budgets for the region surrounding the study area. The local-scale budget has calculation cells representing features on the order of 10s to 100s of meters, and it must be shown separately from the regional sediment budget, with cells ranging from 100s of meters to kilometers.

This paper reviews commonly applied sediment budget concepts and introduces new considerations intended to make the sediment budget process more reliable, streamlined, and understandable. The need for both local and regional sediment budgets is discussed, and the utility of combining, or collapsing, cells is shown to be beneficial for local budgets within a regional system. Collapsing all cells within the budget creates a “macrobudget,” which can be applied to check for overall balance of values. An automated means of changing the magnitude of terms, while maintaining the same dependency on other values within the sediment budget, is presented. Finally, the need for and method of tracking uncertainty within the sediment budget, and a means for conducting sensitivity analyses, are discussed. These new concepts are demonstrated within the Sediment Budget Analysis System with an application for Long Island, New York, and Ocean City Inlet, Maryland.

The lack of systematic studies of the influence of bottom irregularities on ripple initiation led to a series of wave-flume experiments with the purpose of exploring a general relationship. Three types of sand beds with different degrees of roughness were prepared for the experiments: flat, notched, notch-mounded beds. Three kinds of well-sorted sands with different diameters were used for the bed material: fine, medium, and coarse sands. With combinations of waves, water depth, sand, and bed roughness, 248 experimental runs were carried out. Data were analyzed considering (1) the mobility of sediment, expressed in terms of the mobility number, M, (2) the degree of bed roughness, represented by the Reynolds number, Re, and (3) the asymmetry of flow field due to nonlinearity of waves, represented by the relative water depth, kh (= 2πh/L; h = water depth and L = wavelength). The result showed that the threshold for rippling is described by M = 2 A exp B, where A = 5.7 (3.79/(kh 0.65) − 1) and B = −8 × 10⁻⁴ Re. It was found that the threshold decreases with increase in bed roughness and attains constant value with further increased bed roughness. The threshold also decreases as the flow field becomes more symmetric. Comparison between available field data and the present findings shows that the threshold on a well-roughened bed, M = 2, defines the critical condition for ripple formation in the natural environment.

High-resolution bathymetry surveys of Egmont Channel were conducted in 1999 and 2001 using a Kongsberg Simrad EM 3000 multibeam bathymetric system. These data were supplemented with other bathymetry data, seismic profiles, underwater scuba observations, and current velocity data, in order to investigate the geologic and hydrodynamic characteristics of Egmont Channel.

Bounded to the north by a linear steep scarp (∼38°) and by a more gradual slope (>10°) to the south Egmont Channel is an asymmetric tidal inlet and the main shipping channel for Tampa Bay, Florida.

The cross sectional area (17,964 m²) and the tidal prism (6×10⁸ m³) for Egmont Channel were derived in this study. Currents measured at Egmont Deep and the Sunshine Skyway Bridge (∼11 km away) with Acoustic Doppler Current Profilers, have a high correlation (97%) indicating the current velocities at Sunshine Skyway Bridge can be used as a proxy for current velocities at Egmont Deep. Seismic profile data indicate that both the mouth of Tampa Bay and the bay proper contain many stratigraphically controlled depressions. Egmont Deep is located at one of these depressions. Bathymetry and seismic data indicate that the main ebb jet for Egmont Channel is deflected northward by a local stratigraphic high located at the north end of Egmont Key.

The repeated high-resolution multibeam bathymetric surveys document sediment bedform migration. The bottom characteristics of the deep fluctuate due to the erosion and deposition of gravelwaves. Analysis of seismic data and SCUBA observations suggest that the most likely origin for Egmont Deep is a combination of erosion-resistant limestone strata interspersed with pockets of dissolution which is overlain by an irregular bed of mobile sediments. The strong tidal current scour maintains the depth of the feature and assures that any sediment that becomes incorporated in the deep is short-lived.

On a high-energy coast, with heterogeneous nearshore bathymetry and sediment dynamics (New Plymouth, New Zealand), two colours of artificial fluorescent tracer were used to i) investigate the sediment entrapment/bypassing of a port entrance, and ii) to monitor sediment movement from an experimental nearshore dredged-sand dump mound (47,000 m³). Two simultaneous releases (one for each colour) were made in 6 to 10 m water depths, near the port entrance and on the dump mound, 1400 m apart. The tracer was tracked over 10 months by collecting and analysing 1179 surficial sediment samples, with concomitant wave/current recording at up to 13 nearshore sites.

The results demonstrate trapping in the breakwater tip-shoal of the part, by-passing and movement through the complex nearshore reef system. The dominant transport was alongshore. Tracer released near the port entrance depicted a natural sediment “pathway” past the harbour shipping entrance and over the rocky reefs to the beaches 4.5 km away. Very little tracer was detected within the harbour, indicating that the main transport from the release depths (6–10 m) by-passed the harbour entrance and tip-shoal. The tracer shows that only sediments very close to the harbour breakwater (i.e. within 100 m) are trapped at the harbour entrance. From the dump mound, tracer was observed to migrate mostly longshore away from the port, although a minor “updrift” migration was observed.

The tracer results are in accordance with measured and numerically modeled currents, which show a dominant longshore flow away from the port and weak reversing flows in the quiescent lee of the harbour at the dump mound. The tracer data also suggest that the raised shore-normal reefs do not present a significant impediment to longshore transport, but rather that the nearshore circulation patterns are the predominant influence on the sediment transport vectors. Rates of tracer spreading were found to range from 0.095 to 0.288 m²s⁻¹, which is consistent with a high-energy coastal environment. Diffusion and advection of suspended sediments is the primary mechanism of sediment transport, and tracer was found on beaches 4.5 km distant from the release point within 13 days of injection.

In this paper, the geometric characteristics of wave-induced offshore bars are investigated by using physical models. Both regular and irregular waves were used during the testing. Beach sand with a mean diameter of 0.35 mm and a specific gravity of 2.63 was selected for the study. The initial slope of the beach was 1:5. Different wave groups were generated over the initially flat beach, and a number of geometric parameters were determined. These parameters included the location of the bar crest, the equilibrium point, and the closure point. The results of the experimental study were evaluated and some empirical expressions based upon the results are suggested to define those geometric parameters for pure regular waves, pure irregular waves and regular-irregular waves. The proposed formulas were compared with those of Silvester and Hsu (1997). These comparisons showed that a good correlation exists between the results of their earlier formulas and those of the proposed formulas derived for regular waves. It was also determined that the effect of wave types upon the bar crest is more than that of the equilibrium point.

The Eastern Atlantic-Mediterranean boring bivalve Gastrochaena dubia (Mollusca: Gastrochaenidae) has a characteristically ‘8’ shaped calcareous chimney which encircles the siphonal aperture. The ‘8’ length (major axis) is strongly correlated with the valve dimensions (length and height) as well as the volume of the chamber bioeroded by the mollusc. Thanks to the relative robustness of this calcareous structure, it is possible to obtain, using plastiline material directly underwater, moulds of the siphonal aperture. These moulds allow to draw either population structure and bioeroding activity of G. dubia. This new method of measure results to be cheap, accurate and thanks to its non destructive properties, applicable also in Marine Protected Areas (MPAs).

Six species of Charadriidae were recorded at Ilha Comprida beach (South São Paulo State coast, Brazil) during weekly censuses over 3 years (1999, 2000, and 2001). They were grouped in this area taking into account their abundance and permanence on the flat. The first cluster was formed by Charadrius collaris, C. semipalmatus, and Vanellus chilensis, which showed high abundance and were present on the flat throughout the year. The second cluster included Pluvialis dominica and P. squatarola. They were not abundant, and all individuals migrated to North America during the reproductive seasons. The third group includes one species, C. modestus, which was rare; this species was recorded in winter. The number of species and the number of individuals probably fluctuated because of migration or movements among neighboring beaches.

The sensitivity of estimated suspended sediment transport rates was studied by applying existing current-wave fields within a coupled numerical model using the Bagnold and the Soulsby-van Rijn formulae. The study area was the Sylt-Rømø bight, an enclosed back barrier tidal basin located in the North Sea. The bight has an area of some 400 km² in which sand flats prevail. This work provides numerical estimates of sediment transport rates and shear velocities throughout the Sylt-Rømø tidal basin. Water levels, vertically-averaged two-dimensional current velocities and wave spectra were used as input from validated numerical model calculations. Four days covering a full storm period in April 1997 were selected for the calculations of total bed shear velocities and sediment transport rates. The simulation shows that during moderate wave conditions sediment transport mainly takes place in the tidal channels. However, with high wave energy present, sediment transport becomes more important in shallow areas. The general distribution of shear velocities and suspended sediment concentrations over the basin suggests a large erosion and resuspension of sediment in shallow areas by wave action which may not be so evident in the sediment transport rates because of the low current velocities. This suggests that storms will continue to erode shallow areas, thus increasing the tidal prism and probably the tidal currents which will result in the continuing export of sediment.

Because of the severe land loss in coastal Louisiana, many natural nesting areas for the Brown Pelican (Pelecanus occidentalis) are disappearing. Based on field measurements, geographical information system analysis, and a review of the relevant literature, we developed design criteria for the optimal artificial breeding habitat for Brown Pelican. Brown Pelican colonized islands had at least 70% open water within 20 km surrounding the island. Persistent pelican colonies occurred at least 7 km from the mainland and 0.3 km from the nearest island. Long-term colonized islands were between 10 and 70 ha in size with the shrub and dune habitat ranging from 2 to 20 ha on these islands. Pelicans preferred nesting in shrubs, and nesting occurred at an average elevation of 30 cm above mean sea level. We recommend that management for pelican nesting habitat includes loafing habitat: a beach that is at least 28 m wide is recommended.

For approximately 300 years, Tangier Island, located in the middle of the Chesapeake Bay, USA, has been continuously populated by up to 1,000 residents. At present, the population is near 700. The island is very flat and low, and residents live on three sandy ridges with elevations of about 1.0–1.5 m above mean sea level (msl). Over the past century, the relative sea level there has risen about 31 cm, in part due to the estimated subsidence of the island (in other parts of the Bay as well) at a rate of about 18 cm per century. As the level of the sea continues to rise in the 21st century and as shoreline erosion continues, the very existence of the island is in jeopardy. In this article, projections are made to the year 2100 in terms of how sea-level rise and continued shoreline erosion will impact the island. To evaluate impacts, several years of historical tidal levels were extrapolated to the year 2100, using the predicted sea-level changes. The predictions were compared with the observed levels in year 2000 to show the effects of relative sea-level change.

Shoreline erosion was also examined. The first map with enough accuracy to correctly depict temporal changes in shoreline was from 1850. When that map of Tangier Island was then compared with more recent ones, it was found that erosion was much more severe on the western shore due to the longer fetch over which wind-generated waves could develop. Implications for continued human habitation to the year 2100 were examined and the future island size was projected, assuming no additional human intervention beyond the present.