Detailed hydrodynamic and morphological data are presented from a field deployment spanning 2 days (four tide cycles). The data include bed-elevation changes measured at each low tide and continuous records of water-surface elevation, cross-shore and long-shore current velocities, and suspended sediment concentrations all measured within 20 cm of the bed. During the deployment, an intertidal bar migrated onshore and infilled a runnel on its landward side. The depth of this runnel was initially 0.6 m. During the migration of the bar, the significant wave height in deep water was ca. 2 m and wave period was 7 seconds. The significant wave height over the intertidal bar crest was about 0.25 m. Suspended sediment fluxes were estimated (product of current velocity and suspended sediment concentration profile) and partitioned between mean and oscillatory components with the latter further partitioned between short and long wave contributions. When the bar was migrating shoreward and infilling the runnel, estimated suspended sediment flux for all components was directed landward on the bar crest. Once the migrating bar had infilled the runnel, however, the suspended sediment fluxes for the mean component were directed seaward, whereas the short wave-driven flux was still directed landward. These results represent a clear example of morphodynamic interactions—(a) as waves cross the intertidal bar the onshore mean and oscillatory components transport sediment shoreward, (b) the presence of the runnel reduces the offshore component of oscillatory transport by channeling the flow alongshore, (c) the runnel rapidly infills due to the strong transport asymmetry, (d) once the runnel has infilled, the mean cross-shore current and mean sediment flux reverse direction. When the runnel is present, the general intertidal circulation is a horizontal cell circulation with rip currents, whereas it becomes a vertical undertow circulation when the runnel has infilled.

A highly detailed digitized map depicts 22 benthic habitats in 3140.5 km² of the Florida Keys National Marine Sanctuary. Dominant are a seagrass/lime-mud zone (map area 27.5%) throughout Hawk Channel and seagrass/carbonate-sand (18.7%) and bare carbonate-sand (17.3%) zones on the outer shelf and in The Quicksands. A lime-mud/seagrass–covered muddy carbonate-sand zone (9.6%) abuts the keys. Hardbottom communities (13.2%) consist of bare Pleistocene coralline and oolitic limestone, coral rubble, and senile coral reefs. Smaller terrestrial (4.0%) and marine habitats, including those of live coral (patch reefs, 0.7%), account for the rest (13.7%) of the area.

Derived from aerial photomosaics, the seabed dataset fits precisely when transposed onto a newly developed National Geophysical Data Center hydrographic-bathymetry map. Combined, the maps point to new information on unstudied seabed morphologies, among them an erosional nearshore rock ledge bordering the seaward side of the Florida Keys and thousands of patch-reef clusters aligned in mid–Hawk Channel. Preliminary indications are that the ledge may represent the seaward extent of the 125-ka Key Largo and Miami Limestone that form the keys, and the patch reefs colonized landward edges of two noncoralline, non-dune-ridge topographic troughs. The troughs, their substrate, and inner-shelf location along the seaward side of the Hawk Channel bedrock depression are the first of that type of nuclei to be recognized in the Florida reef record. Together, the map datasets establish the efficacy and accuracy of using aerial photographs to define in extraordinary detail the seabed features and habitats in a shallow-reef setting.

This investigation focuses on sedimentological attributes and the litho- and chronostratigraphic framework of Holocene sediment core sections recovered in Alexandria's Eastern Harbor in Egypt, for many centuries the major port in the southeast Mediterranean. Holocene sediment trapped in the harbor, formed of marine calcareous sand, muddy sand, and mud, are examined to define major depositional patterns that developed before and after expansion of Alexandria in the 4th Century BC. Petrologic and radiocarbon data indicate that the harbor formed between two Pleistocene carbonate sandstone (kurkar) coastal ridges and was flooded by seawater during the transgression at about 8000 years before present (BP). Sediments accumulated at an average rate of 1–3 mm/y largely by wave- and wind-driven currents driving material from the Egyptian shelf into the high-energy basin. The association of distinct biological components, failed slump-like sediment strata, and important hiatuses (time gaps) record the episodic influence of powerful events, such as large storm surges, seismic tremors, and tsunamis. These events likely transported marine biota and sediment from the kurkar ridge and inner shelf north of the harbor and also eroded and displaced substantial amounts of older deposits laterally within the basin.

In addition to natural processes, the influence of human activity is detected in harbor sediments after ∼2400 years BP, following development of Alexandria by the Ptolomies and their successors, the Romans. Among important components in cores are artifacts and lithoclasts. The development of important mud-rich deposits from ∼2200 to 1800 years BP is attributed in part to construction of the Heptastadion, the large causeway and aquaduct system built to connect Alexandria with Pharos Island to the north. Structures such as breakwaters have modified sedimentation patterns but do not fully protect the quasi-closed harbor. Ongoing geoarcheological investigations hold promise to more precisely distinguish effects of natural processes from those of human-related activities.

This investigation examined the influence of tissue distribution, gender, reproductive state, temporal variation, salinity, and water temperature on zinc, cadmium, and copper tissue concentrations in two intertidal gastropods, Austrocochlea constricta and Bembicium auratum. More of the variability in total zinc, copper, and cadmium concentrations of both species was explained by trace metal variability in digestive/gonad tissue than by variability in somatic tissue metal concentration. Although there was significant temporal variation in tissue trace metal concentrations, gender, reproductive state, salinity, and water temperature individually did not account for these differences. It was not possible to entirely disentangle the interactions of several concurrent processes such as spawning and mass gain and loss; however, these do not appear to be confounding factors for the use of these gastropods as biomonitors for the comparison of trace metal concentrations between populations at different locations.

Coastal seacliff erosion in California threatens property and public safety, whereas coastal beach erosion threatens the coastal tourism economy. While coastal rivers, seacliffs, and gullies supply the majority of littoral material to California beaches, the relative contributions of these sources are coming into question. These beach-sediment sources must be accurately quantified to formulate proper solutions for coastal zone management.

This study evaluated the seacliff and coastal gully beach-sediment contributions to the Oceanside Littoral Cell using airborne LIght Detection And Ranging (LIDAR). Seacliff and gully beach-sediment contributions were compared with coastal river beach-sediment contributions estimated in previous studies. This study took place over a relatively dry period from April 1998 to April 2004.

The results indicate that seacliffs provided an estimated 67% of the beach-size sediment to the littoral cell, followed by gullies and rivers at 17% and 16%, respectively, over the period of the study. The total volumetric seacliff erosion rates were used to back-calculate average annual seacliff face retreat rates for the study period. These rates ranged from 3.1 to 13.2 cm/yr and averaged 8.0 cm/yr for the Oceanside Littoral Cell.

Comparison of these results to previous studies suggests that the relative seacliff sediment contributions may be higher than previously thought. Conversely, beach-sediment contributions from gullies were significantly lower compared with previous studies. This is likely because of the episodic nature of gullying and the relatively dry study period. Nevertheless, the results of this study indicate that seacliff sediment contributions are a significant sediment source of beach sand in the Oceanside Littoral Cell, and the relative annual seacliff beach-sand contribution is likely higher than previous studies indicate.

Large coastal areas have been closed to shellfishing by fecal coliform pollution. Sources of contamination include humans and animals, with conveyance by storm-water runoff an increasingly important problem in rapidly developing coastal areas. Estuarine waters in southwestern Brunswick County, North Carolina, have long been closed to shellfishing, but sources and modes of fecal contamination have been debated. Water-quality monitoring data allowed evaluation of storm-water runoff and malfunctioning septic systems as causes for closures. Fecal coliform concentrations did not respond to changes in salinity. Plots of fecal coliform concentrations vs. rainfall totals in the 48-hour period prior to sampling at 10 monitoring locations in shellfishing waters revealed no clear rainfall effect. There were no significant differences in fecal coliform concentrations between periods with no rainfall in the preceding 72 hours and 24- or 48-hour periods with any rainfall at 9 of 10 monitoring locations. Fecal coliform concentrations after the highest 48-hour rainfalls (>1.5″) were not significantly higher than the highest concentrations after dry periods. Thus, storm-water runoff alone could not account for fecal coliform contamination in these shellfishing waters. The highest fecal coliform concentrations at monitoring locations within the estuarine watersheds were associated with on-site human waste-treatment systems. Site inspections confirmed that some instances of high fecal coliform counts resulted from improperly performing septic systems. Densities of septic systems reached 20/ha, with many areas of high density having soils severely limited for septic-system suitability. Ditching and drainage systems in densely developed areas facilitated septage discharge to adjacent estuarine waters. Although storm water conveyed some of the total load of nonhuman fecal contaminants, it also conveyed fecal contaminants from poorly performing septic systems, which, under these circumstances, represent important sources of fecal contamination.

In the Wadden Sea of the southern North Sea, severe depletion of fine-grained sediments has been observed since dike construction due to increased energy levels. Of particular interest is the seasonal turnover of the fine sediment fractions. To better understand the seasonal response of muddy sediments, surface sediments, box-core sedimentary facies, and accumulation rates were investigated in a back-barrier basin of the East Frisian Wadden Sea, Germany.

Measurements of accumulation rates indicate that the tidal flats are currently erosional. In summer, fine-grained sediments drape large areas of the nearshore tidal flats, whereas in winter the same tidal flats are dominated by sand. The distribution pattern of grain-size modes shows that in summer the sediment is mostly unimodal, whereas in winter the sediment is bimodal. This pattern is explained by the mixing and unmixing of different source populations in response to seasonally changing energy conditions. Size analyses of the mud fractions have revealed a general dearth of particles around 7 phi. The mud is thus composed of at least two different subpopulations: a better sorted coarse population (<7 phi) and an unsorted fine population (>7 phi). This suggests that the finer particles deposited in summer are incorporated in larger flocs and aggregates, which are hydraulically equivalent to codeposited sand particles; the flocs and aggregates subsequently are broken down and eliminated in winter. The apparent seasonal coarsening/fining is therefore regarded to be an artefact of the mechanical procedure of grain size analysis, in the course of which flocs and aggregates are broken down into their constituent particles. Box core peels confirm that most surface sediments are draped by mud in summer, whereas the sediments display wave-generated sedimentary structures in winter.

A ground-water model was developed for Miami–Dade County Florida, which lies within the Southeast Atlantic Coastal Zone, as a predictive tool that will be used to analyze different water-management scenarios, including regional water-supply plans and the Comprehensive Everglades Restoration Plan (CERP). The model is being developed by the South Florida Water Management District (SFWMD) based on a modified version of the US Geological Survey modular three-dimensional, finite-difference, ground-water-flow model (MODFLOW). This version includes the Wetland and Diversion packages, which are MODFLOW modules that enable the top layer of the grid system to include overland flow through dense vegetation, channel flow through a slough network, and interaction with levees, and thus can closely simulate the natural system.

The model domain is discretized into 430 rows by 367 columns with a uniform cell size of 500 ft × 500 ft (152.4 m). Four horizontal layers are used to represent lithologic zones within the surficial aquifer, one of the most transmissive aquifers in the world, with transmissivity values as high as 300,000 ft²/d (27,870.9 m²/d). Boundary conditions were established by water levels in canals on the northern and southern edges of the modeled region and by water-level measurements in wetlands along the western edge. The eastern boundary with the Atlantic Ocean was determined by using mean tidal fluctuations to calculate the equivalent fresh-water head.

The main advantage of this model, besides the high degree of detail and the number of variables, is that it can simulate hydroperiods within wetland areas using the Wetland and Diversion packages. These packages allow the model to represent the full hydrologic cycle within the wetland areas, including sources and sinks on a daily basis, starting with total precipitation as a driving force.

During calibration (1988–90), a very low sensitivity to conductivity and canal conductances was observed. Therefore, the fit between the model-computed water levels and the observed historical ground-water levels was achieved mainly by adjusting general head boundary conditions and wetland parameters within the active domain. The model is highly sensitive to the operational rules, especially the stages at which the canals are maintained, and is therefore responsive to the way that the system is managed.

Barbados is one of the few localities in the world with uplifted fossil coral reef tracts that provide detailed insights into interglacial sea level change during the Late and Middle Pleistocene. Since the late 1960s, several sea level reconstructions have been established, each contributing to the “Barbados Model” of sea level change. Considering the global importance of paleo–sea level research in Barbados, it is important to note that substantial issues are still unresolved regarding the results obtained thus far. In this paper, we deal with one of the major problems of paleo–sea level reconstruction on Barbados—the assumption of constant uplift—which we test along the Clermont Nose traverse on the southern part of the west coast of Barbados. We demonstrate that uplift along this transect was not, in fact, constant over the last 500,000 years. The data from Clermont Nose strongly support the argument that anticlinal warped areas might have complex tectonic histories and are therefore not necessarily suitable for Pleistocene sea level reconstructions.

The evolution of the barrier-spit terminus of Skallingen was analyzed on navigational charts and aerial photographs. Between 1654 and 1905, the barrier spit Skallingen built up from a nonvegetated dry sandy ridge to exhibit extensive aeolian dune ridges. After 1910, the barrier-spit terminus slowly started to erode and, between 1945 and 2000, barrier-spit terminus eroded almost 2 km toward the northwest, in the opposite direction of the littoral drift. Cut-off of the sediment bypassing and dredging of the tidal channel is found to be the main reason for erosion of the barrier-spit terminus. Storms have affected the west coast of Skallingen and its barrier-spit terminus very differently, as most erosion at the terminus took place before 1981 and erosion on the west coast mostly took place after 1981. Contemporary with the erosion, a flood tidal delta appeared and it has migrated 1740 m since 1974. The front of the flood tidal delta has increased in height and is close to mean high water spring, and about 380,000 m³ of sediment was deposited within this flood tidal delta east of Skallingen between 1990 and 1999.

Dauphin Island, Alabama, is a 22.5 km-long microtidal barrier island/barrier spit in the northern Gulf of Mexico. As a result of the geomorphic and topographic differences across the island, tropical storms and hurricanes impact it in a variety of ways. Hurricane Frederic crossed the western end of Dauphin Island on 12 September 1979. Storm waves measuring up to 4.6 m above the mean high water level washed over much of the barrier spit portion of the island. On the eastern end of the island, one or more storm surges created a well-defined stratigraphic unit that was subsequently buried and preserved by migrating quartz-sand foredunes. The size of the storm-surge deposit was limited by several factors, including the wave run-up energy and the areal extent and elevation of the foredunes. The nature and types of invertebrate faunas found within the surge-wave deposit reflect a nearshore subtidal source (i.e., inner neritic—likely less than 10-m water depth). The storm deposit provides invaluable information regarding the strength and intensity of the storm not directly attainable through atmospheric and sea-wave records and is consistent with washover fan sedimentation from other areas in the Gulf of Mexico.

Reservoir construction and river diversions have dramatically reduced freshwater inflow to coastal salt marshes of the Nueces Estuary, Texas, facilitating hypersaline conditions. To moderate salinities and enhance habitat quality, ∼ 7570 m³ d⁻¹ of treated wastewater effluent was used as a nutrient-rich freshwater source in the lower estuary. For ∼1.5 years prior to and ∼3.5 years following wastewater diversion, we quantified salinity, inorganic nitrogen, and emergent vegetation changes at four stations various distances downstream from the diversion point. Wastewater prevented hypersaline conditions at station 72, closest to the diversion, but not downstream. Increased tidal creek NH₄ and NO₃⁻ NO₂⁻ concentrations were detectable 1200 m downstream, but concentrations were 50%–80% of those measured at station 72 within 325 m downstream. Emergent vegetation responded at station 72 only. Composition rapidly shifted (over a period of ≤ 1 y) from ∼80% monospecific cover of a highly salt-tolerant succulent, Salicornia virginica, to ∼50% cover of a less salt-tolerant shrub, Borrichia frutescens, intermixed with several other species. Percent cover ordination plots on each sampling date verified distinct pre- and postdiversion plant communities at this station. Mean porewater nutrient concentrations were not different among stations postdiversion, but lower C : N ratios and increased δ¹⁵N signatures of B. frutescens confirmed assimilation of wastewater-derived nitrogen at station 72. A variety of plants colonized bare areas near the diversion, creating about seven hectares of newly vegetated salt marsh. Wastewater diversions lowered salinity, increased nutrients, and increased cover of less salt-tolerant vegetation species near the diversion. However, these changes were restricted to a limited area, suggesting that increased diversions are necessary to produce substantial downstream effects.

Super Typhoon Herb caused tremendous damages on the coastal defense structures and severe flooding near and at the National Taiwan Ocean University (NTOU) on the north coast of Taiwan. This article examined nearby structure failures, coastal waves, and water level conditions during this typhoon. It was found that the damaged sections of the coastal structures were related to coastal bathymetry, the severe seas, and great overtopping flows. A wave gauge, which was located 17 km east of NTOU and 30 km from the track of the typhoon center, recorded sea conditions at a mean depth of 11.5 m. The data showed that the recorded highest significant wave height during the storm was 7.8 m, which occurred during the passage of the typhoon center. The maximum wave height at that time was about 10.5 m, close to the breaking limit. It was also found that the time evolution of the wave conditions, including energy spectra, correlated well with the movement of the storm. Right after the typhoon center passed, the wave height quickly died down, much faster than the build-up rate of waves before the center passed. Water level analysis indicated that, historically, the highest storm surge at least in the past 40 years and high wave setups had increased the water level by more than 2 m in the shallow water. Together with high waves and over 5 hours of large overtopping flow rates (greater than 0.02 m³/s/m), superstructures of seawalls and scoured lee-side armor units of breakwaters were broken.

Understanding coastal change at mesotimescales is a prerequisite for developing predictive coastal response models and remains a “holy grail” for coastal scientists and engineers. The historical behavior of the Presque Isle strandplain on the North American Great Lakes provides insight into the complexities of net coastal response to a large set of geoenvironmental variables. Principal among these variables are high-frequency lacustrine transgressions and regressions of up to 1 meter in magnitude that occur at timescales of years to decades against a backdrop of longer term transgression (8 mm/y, 1901–97). Almost a century of coastal processes and anthropogenic modifications have resulted in nearshore net accretion of 15.5 × 10⁶ cubic meters (161 × 10³ m³/y) for this terminal end of a 36-kilometer-long coastal sediment dispersal system. Sediment eroded from the strandplain's updrift transgressive neck sector, coupled with additional inputs from mass wasting of an updrift bluff coast and beach nourishment, is dispersed primarily along-coast to build downdrift regressive shoreface and capping progradational strandplain depositional systems.

Several general rules describe coastal change during quarter century–scale regressive and transgressive lake phases. The downdrift composite spit sector of Presque Isle is always accretional across the entire nearshore profile regardless of lake phase. The response of the updrift transgressive sector is highly variable, and shoreline recession occurs during both regressive and transgressive lake phases. During periods of minor forced regression (−2 mm/y), the Presque Isle nearshore undergoes moderate net erosion, whereas during major transgression (12–15 mm/y), it undergoes minor to major net accretion. In general, erosional and accretional areas migrate on-, off-, and alongshore because transgressive-regressive cycles influence the interaction of natural and anthropogenic sediment source environments with the wave field, which entrains and disperses sediment.

The Middle-Late Holocene infill of the coastal plain of Marathon, Greece, consists of lagoonal deposits related to the decrease of the sea level rise rate. Between a little earlier than 5800 and 3500 Cal BP, mesohaline-oligohaline lagoonal carbonate muds were uninterruptedly accumulating in the central and more seaward areas of the embayment. At the same time in the nearshore environment, oligohaline pelloidal charophytic muds were deposited during periods of a relatively increased rate of sea level rise, whereas during periods with lower rates of sea level rise, extensive marshes were forming in supratidal settings. The formation of framboidal pyrite and evaporitic minerals point to a periodic anoxic, sulfidic, and schizohaline environment. In addition, a warm, strongly seasonal climate under the influence of resurgent continental groundwater is suggested. After 3500 Cal BP, the lagoon witnessed a relatively abrupt change to palustrine mud deposition. The embayment was frequently exposed, and communication with the sea was not perennial. This period, terminated at about 2400 Cal BP, is most likely associated with a wetter and probably more temperate climate. The uppermost depositional unit is dominated mostly by fluvial sediments deposited in a wetland with no recorded communication with the sea. The sea level rise, indicated by several peat formations, is estimated to be lower than that predicted by the glacio-hydroisostatic model and the data from other Greek areas that are considered relatively stable. Hence, a tectonic uplift of the area is suggested at a rate of about 0.4–0.5 mm/y, which almost counterbalances the predicted rate of relative sea level rise of about 0.6–0.7 mm/y for the last 2000 years. This is a plausible explanation for the relative geomorphological stability, since at least Classical times, suggested by the historical documents.