The U.S. Department of the Interior, Minerals Management Service, provides policy direction relative to the development of all marine mineral resources located beneath Federal waters of the United States. Over the last ten years or so, geological studies encompassing the collection and analysis of seismic, vibracore, and grain size data have been conducted in partnership with coastal States in the Atlantic and Gulf of Mexico to locate suitable sources of compatible sand for beach and coastal restoration. Environmental studies have been initiated to provide biological, physical, and other pertinent information for decisions regarding leasing and use of this resource. Aggregate dredging studies also have been conducted in the event that an offshore aggregate mining operation is proposed in the future. A symposium was held in New Orleans in January 2002 to report results from several studies completed over the past 2 years. The papers prepared for this Special Issue summarize the findings of recently completed environmental studies.

Physical processes and biological data were collected and analyzed at five sand resource areas offshore Alabama to address environmental concerns raised by potential sand dredging for beach replenishment. Nearshore wave and sediment transport patterns were modeled for existing and post-dredging conditions, with borrow site sand volumes ranging from 1.7 to 8.4 × 10⁶ m³. Wave transformation modeling indicated that minor changes will occur to wave fields under typical seasonal conditions and sand extraction scenarios. Localized seafloor changes at borrow sites are expected to result in negligible impacts to the prevailing wave climate at the coast. For all potential sand excavation alternatives at borrow sites offshore Alabama, maximum variation in annual littoral transport between existing conditions and post-dredging configurations was approximately 8 to 10%. In general, increases or decreases in longshore transport rates associated with sand mining at each resource area amounted to about 1 to 2% of the net littoral drift, distributed over an approximate 10 km stretch of shoreline. Because borrow site geometries and excavation depths are similar to natural ridge and swale topographic characteristics on the Alabama Outer Continental Shelf, infilling rates and sediment types are expected to reflect natural variations within sand resource areas.

Impacts to the benthic community are expected from physical removal of sediments and infauna. Based on previous studies, levels of infaunal abundance and diversity may recover within 1 to 3 years, but recovery of species composition may take longer. Western areas can be expected to recover more quickly than eastern areas because of opportunistic life history characteristics of numerically dominant infauna west of Mobile Bay.

Physical processes and biological data were collected and analyzed for eight sand resource areas on the New Jersey Outer Continental Shelf to address environmental concerns raised by the potential for mining sand for beach replenishment. Nearshore wave and sediment transport patterns were modeled for existing and post-dredging conditions, with borrow site sand volumes ranging from 2.1 to 8.8 × 10⁶ m³. Wave transformation modeling indicated that minor changes will occur to wave fields under dominant directional conditions and selected sand extraction scenarios. Localized seafloor changes at borrow sites are expected to result in negligible impacts to the prevailing wave climate at the coast. At potential impact areas along the New Jersey coast, wave height changes averaged approximately ±3 to 15% when compared with wave heights for existing conditions. For all selected sand borrow sites offshore New Jersey, average variation in annual littoral transport was approximately 10% of existing values. Because borrow site geometries and excavation depths are similar to natural ridge and swale topographic characteristics on the New Jersey OCS, infilling rates and sediment types are expected to reflect natural variations within sand resource areas.

Infaunal distribution and abundance correlated best with the relative percentages of gravel and sand in surficial sediments. In addition to sediment regime, other physical environmental differences between northern and southern portions of the study area also may have affected infaunal community patterns. Impacts to the benthic community are expected from physical removal of sediments and infauna. Based on previous studies, levels of infaunal abundance and diversity may recover within 1 to 3 years, but recovery of species composition may take longer. The nature and duration of benthic effects may differ with location of mined sites, due to physical and biological differences between northern and southern portions of the New Jersey shelf.

In an effort to assess the possible changes to physical oceanographic processes that might result from alteration of bathymetry as a result of dredging or sand mining, we evaluated the differences in the output of various numerical models run with the natural and hypothetical post-dredging bottom conditions. Fenwick and Isle of Wight Shoals offshore of the Delaware-Maryland border of the mid-Atlantic continental shelf served as the test site. We considered two dredging scenarios, a one-time removal of 2 × 10⁶ m³ of sand from each of two shoals and a cumulative removal of 24.4 × 10⁶ m³, but only the larger appeared significant.

The study of wave transformation processes relied upon a series of runs of the REF/DIF-1 model using sixty wave conditions selected from analysis of the records from a nearby, offshore wave gauge. The model was tuned and calibrated by comparing measured near-shore wave conditions with data calculated using the same measured offshore waves that generated the real near-shore conditions. The modeled, post-dredging data indicated an increase in wave height of up to a factor of two in the area between the dredged shoals and the shore and, in some locations, a lesser increase in breaking wave height and a decrease in breaking wave height modulation. The model results also may help explain the existing pattern of erosion and relative stability.

Application of the well-known SLOSH model (Sea, Lake, and Overland Surges from Hurricanes) for storm surge and POM (Princeton Ocean Model) for tidal currents indicates that the likely dredging related changes in those processes are negligible.

The mining of sand resources from the inner continental shelf for beach nourishment may lead to impacts or increase stress on commercial and noncommercial living resources that utilize these areas. The objective of our work was to characterize benthos present in areas likely to be mined and to predict impacts of sand mining. In 1998 and 1999 we used a combination of methods (grab samples, sediment profile cameras, video sled, and trawl) to collect data on the benthos, both fishes and invertebrates, which utilized several potential sand mining areas. We found benthic communities and fish assemblages to be typical of middle Atlantic sandy inner continental shelf habitats. A sand mining scenario that removed the top meter of sand from Fenwick Shoal would disturb approximately 7.7 km² with the potential acute impact on noncommercial sessile species being the loss of about 150 × 10⁶ individuals representing 300 kg of wet weight biomass that could have functioned as trophic support to fishes. In addition, mobile species would be displaced and have to search for replacement habitat. To minimize impacts and promote recolonization of mined areas the total removal of substrate should be avoided. Small areas with a project area should be left to serve as refuge patches that would promote recolonization and serve as habitat for mobile species. Predicted impacts on demersal fishes would be lessened by a rapid recolonization, particularly the recovery of mobile epifaunal crustacean that serve as the primary trophic support species. Project timing and engineering could also be used to lessen impacts on fishes by reducing stress on crustaceans. For example, mining activities that ended in time for Spring/Summer recruitment would favor crustaceans while a Fall/Winter end would favor annelids.

Ship Shoal, a transgressive sand body located at the 10 m isobath off south-central Louisiana, is deemed a potential sand source for restoration along the rapidly eroding Isles Dernieres barrier chain and possibly other sites in Louisiana. Through numerical wave modeling we evaluate the potential response of mining Ship Shoal on the wave field. During severe and strong storms, waves break seaward of the western flank of Ship Shoal. Therefore, removal of Ship Shoal (approximately 1.1 billion m³) causes a maximum increase of the significant wave height by 90%–100% and 40%–50% over the shoal and directly adjacent to the lee of the complex for two strong storm scenarios. During weak storms and fair weather conditions, waves do not break over Ship Shoal. The degree of increase in significant wave height due to shoal removal is considerably smaller, only 10%–20% on the west part of the shoal. Within the context of increasing nearshore wave energy levels, removal of the shoal is not significant enough to cause increased erosion along the Isles Dernieres. Wave approach direction exerts significant control on the wave climate leeward of Ship Shoal for stronger storms, but not weak storms or fairweather. Instrumentation deployed at the shoal allowed comparison of measured wave heights with numerically derived wave heights using STWAVE. Correlation coefficients are high in virtually all comparisons indicating the capability of the model to simulate wave behavior satisfactorily at the shoal.

Directional waves, currents and sediment transport were measured during winter storms associated with frontal passages using three bottom-mounted arrays deployed on the seaward and landward sides of Ship Shoal (November, 1998–January, 1999). Episodic increases in wave height, mean and oscillatory current speed, shear velocity, and sediment transport rates, associated with recurrent cold front passages, were measured. Dissipation mechanisms included both breaking and bottom friction due to variable depths across the shoal crest and variable wave amplitudes during storms and fair-weather. Arctic surge fronts were associated with southerly storm waves, and southwesterly to westerly currents and sediment transport. Migrating cyclonic fronts generated northerly swell that transformed into southerly sea, and currents and sediment transport that were southeasterly overall. Waves were 36% higher and 9% longer on the seaward side of the shoal, whereas mean currents were 10% stronger landward, where they were directed onshore, in contrast to the offshore site, where seaward currents predominated. Sediment transport initiated by cold fronts was generally directed southeasterly to south-westerly at the offshore site, and southerly to westerly at the nearshore site. The data suggest that both cold fronts and the shoal, exert significant influences on regional hydrodynamics and sediment transport.

An analytical approach that incorporates analysis of nearshore wave transformation and wave-induced longshore sediment transport was developed to quantify the significance of potential physical environmental impacts associated with offshore sand mining. Calculation of longshore sediment transport potential for a series of wave cases provided a method for determining the extent and magnitude of alterations to nearshore processes, but the magnitude of change alone did not provide enough information to determine the significance of changes for a particular coastline. This paper documents a method for evaluating the significance of borrow site impacts that incorporates temporal and spatial variations in the incident wave field. Example applications of this method are presented for borrow sites offshore Oregon Inlet, North Carolina; Martin County, Florida; and Corsons Inlet, New Jersey. As a management tool, this methodology holds several advantages over methods previously employed to assess the significance of borrow site impacts, including: 1) a model-independent component (observed shoreline change) is used to verify model results; 2) impacts associated with borrow site excavation can be directly related to their potential influence on observed coastal processes; 3) site-specific temporal variability in wave climate and sediment transport potential is calculated as part of the methodology; and 4) the procedure accounts for spatial and temporal variability in wave climate, as well as provides a means of quantifying significance of impacts relative to site-specific conditions.

A detailed study of the seabed surrounding dredge pits created during the mining of marine aggregate from a small licence off the south coast of the United Kingdom (“Licence Area 122/3”) has been completed. Over 350 km of high-resolution sidescan sonar imagery and 177 sediment samples have been obtained over a study area extending 10 km either side of the dredge zone (representing one full tidal excursion) in order to identify far-field effects on both physical and biological resources of the seabed.

The physical results presented here for Area 122/3 clearly show that the physical impact of dredging (without screening) on the seabed is limited to a zone within approximately 300 m downtide of the dredge area. This will generally be within the dredge licence boundary due to operational procedures. There is no evidence of suspended sediments falling to the seabed beyond this zone and causing significant changes, which may be manifested as infilling of small pits by fine sediments, siltation within crevices or development of migratory sand ripples. However, there is some statistical evidence from grab sampling that surface sediments have a greater sand fraction within the excursion track of the plume, than those sediments either side. Despite this small change in seabed particle size distribution, the benthic communities do not exhibit a detectable impact, as reported in the accompanying paper by Newell et al. (2002).

Analysis of ADCP backscatter data supports recent evidence for development of a near bed benthic boundary plume some 2–4 metres thick and a few tens of metres wide which extends beyond the limits of the dredge activity. On an extraction licence undertaking cargo screening, this near bed plume may exceed 4.5 kilometres downtide. Such a phenomenon provides a potential mechanism for impacting physical and benthic resources well beyond the dredge licence boundary and requires further investigation.

A survey of benthic macrofauna in the vicinity of a coastal marine aggregate dredging site off the south coast of UK was carried out in 1999. The object of the survey was to determine impact of marine aggregate dredging on community composition, the extent of impact outside the boundaries of the dredge site, and the rate of recolonization and recovery of the fauna following cessation of dredging. Part of the site was intensively dredged by vessels at anchor whilst other parts were less intensively exploited by trailer dredger. The impact of dredging within the intensively exploited anchor dredge site was limited to the dredged area. Impacts included a suppression of species variety, population density and biomass, as well as differences in species composition compared with the surrounding deposits. In contrast, trailer dredging had no impact on community composition of macrofauna within the dredge site.

No suppression of benthic community structure was recorded beyond 100 m from the dredge site. Species variety, population density, biomass and body size of macrofauna was enhanced for as much as 2 kilometers in each direction along the axis of the tidal streams. Whether this reflects organic enrichment derived from the dredge site warrants further investigation.

The rate of restoration of biomass following dredging was slower than that recorded for species diversity and population density. The data for the North Nab study site allow a generalised recolonization sequence to be constructed for coastal deposits.

The Minerals Management Service (MMS) International Activities and Marine Minerals Division is charged with management of Federal Outer Continental Shelf (OCS) sand and gravel resources that would be used for beach nourishment to repair storm damage and protect against sea-level rise. To reduce environmental damage associated with long-term and large-scale use of these resources, a project was funded by MMS to design a comprehensive physical and biological monitoring program for sand-mining activities. An initial task of this project was performance of a literature review to determine where information gaps existed regarding the effects of sand mining and which physical processes and biological resources should be the focus of monitoring. Based upon the literature review and a conference with other investigators, the monitoring program was designed to include the following elements: benthic communities and their trophic relationships to fishes, marine mammals and wildlife (operational monitoring), sediment sampling and analysis, wave monitoring and modeling, bathymetric and substrate surveys, and shoreline monitoring and modeling. Protocols were developed for these elements to ensure consistency of methods among studies. The two primary physical impacts of concern are changes to the sea bed resulting in changes to the erosion and sedimentation processes along the shore and changes to the sea bed that would have a direct and significant impact on the biological environment. The most important biological impacts from dredging to be monitored in this program are changes in benthic secondary production and trophic transfer to fishes.

Ridge and swale topography is exceptionally well developed on the continental shelves of the Mid-Atlantic Bight and the northeastern Gulf of Mexico. In both cases, these linear ridges are oriented parallel to the predominant wave approach direction, suggesting a common process for both their origin and maintenance. Most researchers have concluded that ridges were derived from shorefaces of barrier islands as they retreated across the shelf in response to rising sea level and tides or storm-driven currents maintain them.

The widely cited ridge formation theory of Huthnance (1982) requires a sufficient sand source, currents to move the sand, and an irregularity on the sea floor around which the ridges are initiated. McBride and Moslow (1991) postulated that one of the initial irregularities is a segment of an ebb-tidal delta abandoned by inlet migration. However, the search for other precursors continues. These theories of origin provide little information on how these features maintain their form once they are detached from the shore yet remain in a zone of active wave attack (i.e. in depths less than 20 m). Snedden et al. (1999) indicate that shoals in water depths less than approximately 20 m are migrating shoreward through the influence of Stokes Drift under fair-weather waves based on the work of McHone (1973). However, this model does not explain the maintenance of the form of linear shoal and ridge features.

To assess the impacts of dredging on these features it is essential that a better understanding of the processes that maintain these features be developed. A new conceptual model presented in this paper demonstrates how waves shoaling and refracting up either side of a ridge off the coast of Maryland and Delaware result in convergence of sand transport over the crest of the ridge, thus maintaining the ridge even after it is detached from shoreface processes.

The possibility that these ridges might deflate or disappear as a consequence of dredging, resulting in dramatic changes in wave conditions along the shore, is a major concern. The application of a spectral or phase-resolving wave model combined with two-dimensional hydrodynamic and sand transport models as applied in this paper represents a method to evaluate this potential impact of dredging.

With the increased demand for Federal sand and gravel resources on the outer continental shelf, the Minerals Management Service (MMS) is developing strategies for environmentally sound and fiscally responsible management of the resource. A process is needed for planning, decisionmaking, and coordination among stakeholders. Two workshops were conducted in Texas and New Jersey to solicit input from Federal, State, and local government representatives, university researchers, and private companies on key issues. Based on the results of the workshop, it was recommended that sand management task forces be established in each state, starting with those states that can provide a strong technical and administrative lead and have a high level of interest in accessing Federal borrow sites. Sand management task forces would be responsible for planning, coordinating, and facilitating the use of OCS sand for beach nourishment and coastal restoration projects. MMS's responsibilities include taking the lead in the design and funding of long-term monitoring studies of the impacts of dredging OCS sand, sponsoring workshops on technical and policy issues, and providing a clearinghouse for dissemination of studies and findings on actual environmental impacts, focusing on key issues such as cumulative impacts.

The simplest description of a given coast requires a minimum of three terms, embracing the following: (1) material (hard/soft; soluble or otherwise); (2) agencies (erosive/constructive; physical, chemical, biological, and geographic setting [latitude, exposure, fetch]), and (3) historical factors (time scale: geotectonic, glacioisostatic, eustatic, steric, anthropic). Deductive reasoning based on instrumental data such as tide gauges frequently lead to misleading conclusions, in that most are located in the northern hemisphere (land-dominated), near river mouths (variable runoff), sediment compaction, crustal lowering, coriolis effect of geostrophic current variation, and excessively short data spans (< 100 yr). Climatic oscillation influences sea level on all scales from ENSO (El Niño Southern Oscillation) and NAO (North Atlantic Oscillation) up to 1500 yr or more. Satellite observations furnish only the briefest “snap-shots.”

Classifications based on perceived “relative” relationships such as submergence or emergence are useful as generalizations, but only when provided with the time scale. Similar constraints apply to subsidence and uplift, and always subject to the three fundamental criteria.

Many different kinds of classification have been applied to coasts in attempts to characterize dominant features in terms of physical or biological properties, modes of evolution, or geographic occurrence. Some of the earlier general classifications were broad in scope but lacked specificity while other specialized systems were narrowly focused, providing uneven coverage of taxonomic units for coastlines of the world. Due to more comprehensive study of coasts and the increasing availability of information, especially digital formats in GIS frameworks, integrated and systematic approaches to coastal classification are favored. The complex demands of today require sophisticated solutions to overlapping and interrelated problems in the littoral, as facilitated by organization of biophysical parameters into a coherent whole or universal scheme. The developmental approach to a new comprehensive classification system is thus proposed for the coastal fringe, a swath zone 5 to 10 km wide across the shoreline, which incorporates all important parameters necessary to categorize geomorphic units that can be mapped at meaningful scales. Consideration of coastal geomorphological properties are the theme of this approximation toward a modern taxonomic system where morphostructures are the unifying links that facilitate transition from one hierarchical level to another. The proposed approach employs differentiating criteria for hard rock (automorphic) and soft rock (allomorphic) coasts which are divided by chronometric parameters related to the antiquity of littoral landforms. Other levels of primary differentia include geodynamic-climatomorphogenic process zones, relief types (morphoregions), morphogenetic relief features, and relief elements and genetically homogeneous surfaces. Morphotypes are lower level taxons that provide examples of ingressional, egressional, and complex process-forms. The proposal for a unified system requires testing in the field and mapping at myriametric scales to update subsequent approximations.

Beach nourishment is increasingly seen as an appropriate management solution in areas which are experiencing beach erosion. Such a scheme has been implemented along the Lincolnshire coast between Skegness and Mablethorpe, on the east coast of England, since 1994. Poorly sorted, gravelly sandy sediment has been placed on the beaches in a gently sloping seaward profile to raise beach levels and protect the hard defences from wave attack. Grain size analysis of beach sediments, topographic profiling and remote sensing have been used to monitor the beach response. After nourishment, wave reworking caused a rapid redistribution of sediment over the beach profile during the succeeding weeks. Coarse sediment has remained on the beach berm, while finer sediment has migrated to the lower beach and sub-tidal zone. The berm face has correspondingly become steeper, producing more wave reflectance, and further scour and erosion of lower beach sediment, although there appears to have been little alongshore sediment transport. The most severe sediment loss has occurred around promontories and on the central portion of the convex-shaped coast which experiences greatest wave exposure. While the nourishment scheme has improved the standard of defence, further sediment losses could be reduced by nourishing the beach with a more natural size grading, promoting a flatter beach profile and increasing the dissipation of wave energy. Unless stabilization of the beach profile can be achieved, further periodic renourishment will be required to maintain relatively high beach levels.

The SW-Finnish archipelago presents a skerry coastline mosaic of land and sea under the influence of post-glacial land uplift. These conditions give rise to some dynamic and transitional geomorphological processes in the shoreline. The land uplift preserves the landforms as the shoreline processes cease to affect their development. Tombolos are isthmuses formed of sedimentary material between adjacent islands by shore processes. In the study area they are a few tens of meters long with varying details, often with the presence of boulders that have probably been concentrated on the site by ice push. The 203 tombolos found in this study are distributed widely across the study area, but they abound near esker and moraine areas. Narrow-mouthed flad-bays and near-shore glo-lakes represent other characteristic shore types in the region with 370 and 82 occurrences, respectively. Both of these formations are remarkably common in those parts of the archipelago where the islands are formed of highly fractured bedrock. We argue that the abundance of these landforms in the SW-Finnish archipelago is also a significant phenomenon in the global context, since usually these types of formations occur as individual incidents only. The presence and dynamics of these special shore forms in the region need to be recognized in coastal management and conservation planning.

An analysis of tide-gauge and atmospheric data reveals that a transient, unusual sea-level drop occurred in mid-April 1997 along coasts of the Nisyros island volcano, SE Aegean Sea. This event had an amplitude several times larger than the average tidal range (∼6 cm) and caused a transient shift of coastal biological zones and a biological anomaly, the signs of which survived for at least one year. This proves first, that the observed sea-level low was an effect of meteorological origin, not related to a clustering of seismicity which affected Nisyros and the wider area. Second, that the coastal biological zoning and the Biological Mean Sea Level (BMSL) are stable and characteristic in each site, and do not depend on short-wavelength fluctuations of the sea level. And third, that biological observations can be used to identify the detailed history of recent sea-level changes caused by tectonic, volcanic or even meteorological effects; the amplitude of such changes may be as low as a few tens of centimeters. An implication of the above is that in rocky, nearly tideless and low-energy coasts, BMSL (which generally corresponds to the Mean Low Waters during spring tides) approximates Mean Sea Level (MSL) with an accuracy similar to that obtained from ∼1 year long tide-gauge records, and therefore can define a geodetic datum suitable for all engineering projects.

This paper investigates the spatial and temporal variability of three different mixed sand and gravel beaches on the Suffolk coast, U.K. The beaches consist of a highly variable mixture of medium (−3.3 to −3.47 ϕ), moderately sorted gravel (0.85 to 0.78 ϕ), and 15 to 30% coarse (0.47 ϕ) moderately sorted (0.96 ϕ) sand. Above the high water mark beach sediments are predominantly gravel, whilst the sand fraction is concentrated in a planar region of the lower foreshore.

The beaches studied exhibit some characteristics of pure gravel beaches, some of pure sand beaches and some which are unique to mixed beaches. Distinctive sedimentary features include a coarser sand fraction and finer gravel fraction, the existence of multi-modality within the gravel fraction, very limited shape sorting, and high spatial and temporal variability. Beach profile responses are similar to those of pure sand and pure gravel beaches, including those changes occurring over semi-diurnal, spring-neap, and seasonal timescales. Some storm responses were also similar, including the formation of beach scarps, large ridges, reduced lower foreshore levels and a wide planar beachface region. However, beach profiles can flatten or steepen under storm conditions depending on the presence of seawalls at the back of the beach.

A conceptual model for beach accretion is developed which involves ridge formation on the upper foreshore and subsequent onshore migration to form beach ridges under high energy conditions. Post storm recovery is seen to rely on the accretion of these beach ridges. On the lower foreshore, accretion does not involve ridge accretion and occurs under lower energy conditions. The importance of sediment supply, beach width and nearshore water depth are also discussed.

British Columbia hosts Canada's most rapidly developing coastal communities along the semi-enclosed waterways of the Strait of Georgia. This region also is Canada's most seismically active zone. In 1946, the Vancouver Island M7.3 earthquake caused a number of submarine failures of sand and gravel shoreline deposits, destroying coastal facilities, shearing submarine cables and causing large, destructive waves. Multibeam and sidescan sonar technologies have been used to map three submarine landslides at Goose Spit, Mapleguard Spit and Grief Point. These sites are 32–55 km from the epicentre. The data image the failures in great detail, providing important information on size and style of mass-wasting. The total combined area affected by these three failures is over 1.3 × 10⁶ m². Submarine cores show the spit failures consisted of well-rounded beach gravel, cobble and sand, in some cases suspended in a cohesive mud matrix, while the Grief Point failure was likely a debris flow avalanche. Cone penetration tests at Goose Spit show soil profiles prone to liquefaction, lateral spreading and post-liquefaction landsliding with reasonably low ground accelerations.

Our objective was to evaluate the influence of water quality and sediment chemistry on the survival and growth of Halodule wrightii transplanted onto unconsolidated dredged materials in Lower Laguna Madre, TX. Subsequent to transplanting activities, we measured environmental conditions and seagrass parameters at transplant and natural beds over a 1-yr period. Although water quality characteristics at the transplant and comparison sites were compatible with seagrass growth, transplants failed to survive for more than a few months. Seagrasses at natural sites received high light (>6000 mols m⁻² y⁻¹) and exhibited typical patterns of annual growth, biomass and density as well as sediment chemical parameters. In contrast, the estimated annual quantum flux of 2500 to 3200 mols m⁻² y⁻¹ at the transplant sites was near the minimum light requirements for H. wrightii. The marginal light environment was a consequence of high turbidity from wind-driven sediment resuspension. Sediment erosion at the transplant site also resulted in a 30 cm increase in water depth. Sediment NH₄ concentrations at the transplant sites were at or above the maximum values for Texas seagrasses (up to 600 µM). Although NH₄ is generally considered a nutrient, recent evidence suggests that moderate to high NH₄ concentrations can be toxic to below ground tissues. We hypothesize that substrate loss, chronic stress from elevated sediment NH₄ levels coupled with minimal light caused the demise of the H. wrightii transplants. Consequently, this work illustrates the importance of site history and sediment bio-geochemistry as factors that control the success of seagrass transplanting efforts.

Although numerous field studies have evaluated flow and transport processes in salt marsh channels, the overall role of channels in delivering and removing material from salt marsh platforms is still poorly characterised. In this paper, we consider this issue based on a numerical hydrodynamic model for a prototype marsh system and on a field survey of the cross-sectional geometry of a marsh channel network. Results of the numerical simulations indicate that the channel transfers approximately three times the volume of water that would be estimated from mass balance considerations alone. Marsh platform roughness exerts a significant influence on the partitioning of discharge between the channel and the marsh platform edge, alters flow patterns on the marsh platform due to its effects on channel-to-platform transfer and also controls the timing of peak discharge relative to marsh-edge overtopping. Although peak channel discharges and velocities are associated with the flood tide and marsh inundation, a larger volume of water is transferred by the channel during ebb flows, a portion of which transfer takes place after the tidal height is below the marsh platform. Detailed surveys of the marsh channels crossing a series of transects at Upper Stiffkey Marsh, north Norfolk, England, show that the total channel cross-sectional area increases linearly with catchment area in the inner part of the marsh, which is consistent with the increase in shoreward tidal prism removed by the channels. Toward the marsh edge, however, a deficit in the total cross-sectional area develops, suggesting that discharge partitioning between the marsh channels and the marsh platform edge may also be expressed in the morphology of marsh channel systems.

The impact of beach nourishment on the development of coastal dunes was studied along the Dutch coast. A database of annual cross-shore profiles was analysed to derive volumetric changes associated with aeolian and hydrodynamic processes. The database covered a period of 15 years. Beach nourishment projects that were carried out arbitrarily within this time-span were selected, and the volumetric changes occurring on the selected sites were statistically related to the number of years following nourishment. An overall negative sand budget was found for the supratidal zone of the nourished sites. A substantial part of the sand was blown to the foredunes. One year after nourishment, this amount increased significantly. At the same time, the supratidal beach was eroded more. In the second and third year after nourishment, the erosion of the higher parts of the nourishment decreased. In the foredune, dune toe erosion due to storm surges was usually negligible until the fourth year following beach nourishment. Thus, beach nourishment temporarily protected the adjacent foredunes from being eroded by periodic wave attack, and also temporarily enlarged the aeolian sand transport rate to the dunes.

While the effects of major hurricanes have been intensively studied, less is known about the impact of the weaker but more frequent tropical cyclones, such as Hurricane Georges (1998). This hurricane, Category 2 at landfall, was non-typical in its effects. While high waves offshore and slow forward speed just before landfall resulted in island degradation, identical to that of Category 5 Hurricane Camille in 1969, the impact on the mainland was quite different. Only approximately 15% of the sand volume eroded by Camille in 1969 was removed from the Harrison County's mainland beach this time. Backshore areas of East Belle Fontaine Beach have prograded by 3–7 m. 20–90 cm vertical aggradation took place at several locations on its 10–45 m wide backshore. The short duration of hurricane-strength winds over the mainland and the availability of compensating sand supplies from adjacent sediment sources in the waning phase of the storm explain the limited extent of mainland shore erosion. Retreating shore bluffs and backfill from demolished bulkheads replaced eroded beach sand. Sand derived from artificial dunes on the backshore and from sand-rich nearshore areas have also mitigated effects of wave erosion.

Even with the development of modern technological equipment, the Emery-Method is still a widely used and straightforward tool for measuring beach profiles, especially in tropical developing countries, where often lack of infrastructure and unfavourable climatic conditions, among others, restrict the application of sophisticated electronic devices. This article focuses on its performance in a coastal environment adjacent to mangroves and proposes some modifications to the original method. Examples of applications during a long-term study and findings of error measurements are presented. Inaccuracies result from the properties of different sediment surfaces and systematic errors. For a given error margin, the minimum beach slope should not fall below a certain value.

Observations at sea, and ensuing logging of oceanographic data, was done centuries ago by captains according to norms varying from one flag to another. The idea to set up a uniform system and a “corps of observers” lies at the basis of the “First International Conference” on meteorology and oceanography (Brussels, 1853). Maury and Quetelet were central figures of the event. Quetelet is known as perhaps the first major organizer of international meetings. He is also considered as the “father of modern statistics”. Maury is, for many historians and oceanographers alike, the “father of oceanography”. Whether these reputations are deserved is not crucial, but they were the cogs that animated the first international conference on meteorology and oceanography.