Coastal plumes, which carry run-off from land, influence the circulation patterns and ecology of nearby coastal areas, causing eutrophication, turbidity, and spread of harmful pollutants. They can be observed along many coasts. Estuarine and ocean fronts result when denser water under-rides lighter water giving rise to an inclined interface and a strong convergence at the surface, which can concentrate phytoplankton and pollutants. To detect and map fronts and plumes, remote sensors exploit their differences in turbidity, color, temperature, or salinity from ambient background water. The most effective remote sensing techniques for observing coastal plumes and estuarine/ocean fronts are reviewed. Studies are presented, which use data from multispectral and hyperspectral imagers, thermal infrared (TIR) radiometers, microwave radiometers, and Synthetic Aperture Radar (SAR). Mounted on satellites and aircraft, these sensors provide the spatial/temporal resolution and coverage needed for tracking plumes and fronts, including their high temporal and spatial variability. This article reviews the most effective remote sensing techniques for observing coastal plumes and ocean fronts and illustrates the application of these techniques in a case study.

Mombasa is the second largest city in Kenya and the largest international seaport in East Africa, with over 650,000 inhabitants. The city has a history of natural disasters associated with extreme climatic events, most recently, the severe rain-induced flooding in October 2006, which affected about 60,000 people and caused damage to important infrastructure. Because the city is expected to continue to experience rapid growth, the future impacts of such events can only increase. Changes in sea level and storm surges are components of climate change that have the potential to further increase the threats of flooding within the city. This geographic information system–based study provides a first quantitative estimate, both now and through the twenty-first century, of the number of people and associated economic assets potentially exposed to coastal flooding due to sea-level rise and storm surges in Mombasa. The current exposure to a 1 ∶ 100 y extreme water level for the Mombasa district is estimated at 190,000 people and US$470 million in assets. About 60% of this exposure is concentrated in the Mombasa Island division of the city, where about 117,000 people (2005 estimate) live below 10 m elevation. By 2080, exposure could grow to over 380,000 people and US$15 billion in assets, assuming the well-known A1B sea-level and socioeconomic scenario. Future exposure is more sensitive to socioeconomic than climate scenarios. However, there is significant scope within the city limits to steer future development to areas that are not threatened by sea-level rise. Hence, forward planning to focus population and asset growth in less vulnerable areas could be an important part of a strategic response to sea-level rise. The methods used here could be applied more widely to other coastal cities in Africa and elsewhere to better understand present and future exposure and worst-case risks due to climate change and rising sea levels.

It has been well established that numerous coastal areas are threatened by sea-level rise and coastal flooding. Some of these vulnerable lands contain significant archeological sites and cultural resources. The accurate calculation of shoreline rates of change and identification of coastal hazard zones for areas containing cultural resources is crucial for the development of effective coastal zone management strategies that address resource conservation and preservation. This investigation employed geospatial and analytical statistical techniques to conduct a shoreline change study on Rainsford Island occurring from 1944 to 2008. The 4.45-ha island, located in Boston Harbor, Massachusetts, consists of two heavily eroded drumlins connected by a low-lying bar. Past archeological surveys have concluded that Rainsford Island has numerous historical sites and is an area of high prehistoric sensitivity. A recent geophysical survey mapped a Revolutionary War era cemetery on the island. Multiple data sources were integrated, including historical maps, aerial photographs, and airborne laser topographic data for shoreline delineation over various temporal and spatial scales. The Digital Shoreline Analysis System was used to determine rate-of-change statistics and distances, and to identify hotspot areas of erosion and accretion. The results show that the island eroded during the study period at a rate of 0.05 m/y on average, with erosion rates as high as −0.59 m/y. The bar has migrated SE resulting in erosion along the island's northern shoreline. Predictive modeling indicates that 26% of the island would become inundated with 1 m of sea-level rise including the area containing the cemetery.

High concentrations of nutrients from agricultural and urban runoff, or those produced by coastal upwelling, are causing algal blooms in many estuaries and coastal waters. Algal blooms induce eutrophic conditions, depleting oxygen levels needed by organic life, limiting aquatic plant growth by reducing water transparency, and producing toxins that can harm fish, benthic animals, and humans. The magnitude and frequency of phytoplankton blooms have increased globally in recent decades, as shown in data from ocean-color sensors on-board satellites. Satellite and airborne measurements of spectral reflectance (ocean color) represent an effective way for monitoring phytoplankton by its proxy, chlorophyll-a, the green pigment that is present in all algae. This article reviews the use of remote sensing techniques for detecting phytoplankton and mapping algal blooms. Two case studies are presented, illustrating the advantages and limitations of satellite and airborne remote sensing.

The impacts of human activities on the sediment load of the Yellow River and the long-term evolution of the delta have been extensively investigated, but less is known of the variation in sediment grain size in the littoral zone. In this study, the data of surface sediment samples collected from the littoral area of the Yellow River Delta in 2000 and 2007 are used to investigate the spatial distribution and transport pathway of the sediment, as well as the grain size response to the drastic decrease in riverine sediment discharge. By applying the geostatistics analysis method to grain size parameters in determining the characteristic distance in the sediment trend analysis method, an effective way to understand the movement and gradation of surface sediments around the delta has been proposed. The results show that as a whole the sediment in the inshore erosion area is coarser than that in the offshore accretion area. The grain size trends obtained reveal two converging zones of sediment movement. We find a coarsening trend in sediment from 2000 to 2007. Possible mechanisms for this trend are discussed.

Changes in land use influence surface-water quality and thus present a potential threat to coastal ecosystem health. Land use–land cover changes (LULCC) in the lower Eastern Shore watersheds of Maryland have been rapid in the last decade, with increase in real estate development an obvious indicator. The objective of this study was to evaluate the extent of historical LULCC in the lower Eastern Shore watershed and coastal bays of Maryland from 1986 to 2006. Land use–land cover data were derived by supervised classification of Landsat TM 5 satellite imagery acquired in 1986, 1996, and 2006 using the Anderson level-1 classification system in Environment for Visualizing Images (ENVI 4.5), while LULCCs were detected in an Arc-GIS 9.2 environment.

The results showed that while urban and forest lands increased by 121.8% and 8.5%, respectively, in the lower Eastern Shore from 1986 to 2006, croplands and wetlands decreased by 19.6% and 21.3%, respectively. Area covered by surface water increased by 10%, submerging mostly wetlands of 150 km² in 17 of the 23 subwatersheds studied. The loss of these coastal wetlands is attributable in part to the changing climate and the resultant sea-level rise and in part to the activities of the invasive rodent Nutria (Myocastor coypus), reported to be a major menace in Maryland's Eastern Shore. The declining wetlands have serious ecological health implications for the Chesapeake Bay and its watersheds for several species and thus require urgent attention. More intensive and frequent monitoring of this delicate estuarine ecosystem is suggested.

The present work analyses the spatial and temporal variations of the herbivorous fish assemblage on 10 coral reef sites in the Caribbean island of Guadeloupe (French West Indies). The herbivorous fish assemblage was assessed by visual census along band transects; environmental data were collected to determine the relationship between environmental conditions and temporal and spatial variations in herbivorous fish abundance and distribution. Spatial variation in species abundance was related to variation of the benthic cover (e.g., coral and algae), depth, and protection status among sites. Short-term fluctuations of herbivorous fishes on the reef flats were linked to tide, swell, and wind, whereas long-term variations were seasonal and highly correlated to annual water temperature oscillations.

A new technique of predicting a one-dimensional wave transformation due to bottom variation was developed by using analytical and numerical approaches. The coefficients of the governing equation, the mild slope equation, were approximated as polynomial forms using the least squares method. The power series technique was applied to solve the second-order ordinary differential equation originally converted from the mild slope equation. Because the approximation was carried out after setting the coefficient of the highest-order term of the equation to unity, there was no singular point. This solution became, consequently, applicable to arbitrarily varying topography. Comparison of results from this study with the numerical solutions calculated by the finite element method showed good agreement for various cases.

Significant urban development surrounding the Gold Coast Broadwater and upper catchment has resulted in concerns about degrading water quality of the estuarine system. The Gold Coast Seaway plays an important role in the exchange of estuarine and oceanic waters influencing the intertidal waters of the region. Water quality within the Gold Coast Seaway and the immediately adjacent Broadwater was investigated three times at three sample depths at 13 sample locations. Conductivity, temperature, and depth casts, total (nitrogen and phosphorus) and dissolved inorganic (NO_x and NH₄ ) nutrients, and fecal indicator bacteria were measured at hourly intervals to compare the water quality under different tidal conditions at each location. Hydrological data were also collected. From these measurements, the intratidal variability of the Seaway waters was determined. Observed current velocities ranged from 0.001 to 0.909 m s⁻¹ and 0.018 to 1.8 m s⁻¹ during neap and spring tide periods, respectively. Physical parameters and nutrient concentrations demonstrated typical cyclic variations, with the influence of tidal and diurnal cycles apparent. Near minimum and maximum concentrations were generally observed at high and low water, respectively, indicating the influence of oceanic water during flood tides and catchment waters during ebb tides. Significant correlations were observed between surface water salinity values and total nitrogen and phosphorus concentrations. Fecal coliforms and Enterococcus spp. concentrations were low (<60 colony-forming units per 100 mL⁻¹), with no significant trends apparent between concentration and sample location, depth, or tidal phase.

The hydrogeochemical characteristics of shallow groundwater in the coastal areas of Kodiakarai have been investigated using geochemical analysis and statistical techniques. The geochemical data (electric conductivity, pH, total dissolved solids, Ca, Mg, Na, K, NO₃, SO₄, Cl, and HCO₃) of the water sample indicates that this water not suitable for drinking. The spatial distribution pattern indicates the total dissolved solids and electric conductivity were highly concentrated on the northeastern side, and that of sodium and chloride on the southwestern and northeastern side. The statistical treatment of the data (cluster, factor analysis) indicates three types of groundwater in the study area and that seawater incursion is the dominant process that influences the quality of the groundwater in the coastal region.

Seagrass restoration has often not been successful due to poor site planning, physical disturbance, transplant timing incompatibility, and physical and biological disturbances. As such, these factors are important for successfully restoring seagrasses, and global success has greatly increased. We conducted restorations in the mid-Atlantic region of the United States to reestablish this valuable habitat. Our restoration efforts in New Jersey involved transplants of both Zostera marina (eelgrass) and Ruppia maritima (widgeon grass). We found that Z. marina site success and transplant survival increased over the scope of this 4-year investigation (66%–100% and 34%–43%, respectively). However, R. maritima success was heavily dependant upon the year planted; with limited success in 2002 (12%) and high success during 2003 (80%), most likely related to the brown-tide bloom and nonbloom associated with these planting years. For both species restored, ecosystem function was becoming established by the end of the study, demonstrated by their ability to trap and bind fine particulate matter. We provide evidence from this study that seagrass restoration is a viable option for coastal managers and that once established, seagrasses can recover and expand.

The landing of Indian oil sardines, Sardinella longiceps Valenciennes, 1847, along the southwest coast of India is highly variable. A few physical parameters and processes correlated with sardine landing could not establish a flawless connection and explain the phenomena of interannual variability. Earlier research has indicated that the probable appearance and disappearance of sardines is an active movement in search of food and favourable conditions. But no specific study has been carried out to explain the variability of sardine catch based on chlorophyll availability on a synoptic scale. An attempt is made in this study to correlate variability in chlorophyll a with sardine landings along the waters of the southwest coast of India. We have estimated monthly averaged surface phytoplankton biomass along the waters of the southwest coast of India from the shoreline up to the 200-m isobath for 10 years from SeaWiFS ocean-colour data. This estimation is compared with the biological calendar of Indian oil sardines. The average chlorophyll a for the bloom initiation month (1998–2006) matches very well with oil sardine landings. The results imply that the concentration of chlorophyll during the bloom initiation month can be used to assess the quantity of fish that recruit into the population. Finer scale spatial variations in the chlorophyll along the coastal waters help in deciphering the migratory pattern of sardines during their active breeding phase. This study shows that 39% of interannual variability in fish landings is related to availability of chlorophyll a during the bloom initiation month.

Traditionally, an edge wave is measured along a long and straight coast with pressure-gauge arrays to acquire the frequency-wavenumber for dispersion relationships. Ideal measurement locations are limited, and the cost of purchasing and operating some 20 instruments emerges as a threshold requirement. In the present study, one instrument measuring both the bottom pressure and the flow velocity was used to retrieve edge-wave information on the east coast of Taiwan outside the Hua-Lien Harbor. Using the progressive linear-wave assumption for irrotational and inviscid shallow water provided the pressure-flow relationships for both the infragravity edge and leaky waves. The relationship for edge waves was helpful in identifying the edge-wave mode, whereas the relationship for the leaky waves eliminated the possibility of incorrectly interpreting a leaky wave as an edge wave. Applying this approach to field measurements on the east coast of Taiwan shows that a Stokes edge wave is a significant component in the band of period 70–120 seconds before the landfall of a typhoon coming from the southeast but still hundreds of kilometers from Hua-Lien Harbor. This result suggests that the approach being presented can be applied in the real ocean, and a unique method for taking into account edge waves may need to be considered for the resonance problem that occurs in Hua-Lien Harbor during passing storms.

The effectiveness of measures in protecting the coast against natural hazards depends on the extent of run-up by ocean waves, which is an essential parameter in their planning and design. Although, several formulae have been derived in the past for estimation of run-up in laboratory studies for a variety of wave front structures, certain uncertainties still remain pertaining to flat slopes and long waves. To understand the performance characteristics of vegetation in attenuating run-up, a comprehensive experimental investigation was taken up. The studies were carried out with regular and cnoidal waves propagating over a plane slope of 1 ∶ 30 in the presence and absence of vegetation of different characteristics. The results on the variation of dimensionless run-up as a function of wave and vegetal parameters are presented and discussed in this paper.

In this article we research the design of detached breakwaters, a type of coastal defence work designed to combat erosion on beaches in a stable, sustainable fashion. Our aim is to formulate a functional and environmental (nonstructural) method of design that defines the fundamental characteristics of a detached breakwater as a function of the desired effect on the coast whilst meeting social demands and preserving or improving the quality of the littoral environment. We aim to make this method generally applicable by considering relations between variables of different natures (climatic, geomorphologic, and geometric) influencing the changes experienced on the coast after the detached breakwater has been built. We carried out the study of the relations between the different variables on the data from 19 actual, existing detached breakwaters on the Spanish Mediterranean coastline, and we followed a methodology based on the implementation of nondimensional monomials and on a search for relations of dependency between them. Finally, we discussed the results obtained and came up with a proposal for a design method that uses some of the graphic relations found between the variables studied and that achieves the main objective. For example, a case of a detached breakwater's geometric presizing is solved as a practical demonstration of how the method is applied.

Beach litter is harmful and costly in many ways, and the number one form of litter on U.S. beaches is cigarette butts. Campaigns for smokeless beaches have been based largely on environment and aesthetics, but health and economic factors are also important. Beach tourism is often the most important source of revenue for coastal communities, and surveys have shown that the foremost requirements for beachgoers are clean sand and clean water. The present paper introduces a study of the smoking bans adopted so far on some U.S. beaches.

Surface discharge of negatively buoyant effluents into moving waterbodies creates a range of complex flow behavior. These complexities in the hydrodynamic phenomena develop through the interplay between a discharge's initial fluxes and the motion of the ambient current, which advects the discharge fluid downstream. In the present study, experiments were conducted for a comprehensive range of initial fluxes for negatively buoyant discharges in an ocean current through rectangular and semicircular channels. From this data, three flow regimes—the free surface jet, the shore-attached surface jet, and the plunging plume—and their range of occurrences were identified. These observations provide the basis for developing a revised flow classification diagram, which differs significantly from the positively buoyant discharge scheme as expected. A major difference is in the transition from the free surface jet regime to the shore-attached surface jet, whereas the plume-like regime has the same transition criteria. Eventually, using the developed diagrams, an initial tree-like classification framework is developed for both semicircular and rectangular discharge channels.

Four sediment cores were collected in Suruí Mangrove. Cores 0.30-m long were sliced into small cores corresponding to 0–0.03, 0.05–0.10, 0.10–0.15, 0.15–0.20, 0.20–0.25, and 0.25–0.30-m depths. Polycyclic aromatic hydrocarbons, total organic carbon (TOC), and total sulfur (TS) were determined. Total organic carbon varied between 0.8% and 7.8%, with mean values varying according to sampling location (5.2% for core 1, 3.2% for core 2, 4.2% for core 3, and 2.7% for core 4). Total sulfur also varied in the studied cores with a mean ± standard deviation of 1.1% ± 0.7%. The lowest value (0.01%) was found in core 2 (0.10–0.15 m), and the largest one (2.6%) was observed in core 4 (0.25–030 m). The TOC/TS ratio indicated that most sediments showed reducing characteristics, except for four samples (core 1 of 0.10–0.15 m and 0.25–0.30 m, and core 2 of 0–0.03 m and 0.05–0.10 m). Total PAH concentrations varied between 4.4 and 1387 µg g⁻¹, indicating a local and restricted contamination of parts of the studied area. The highest percentages for total and carcinogenic PAHs and toxic equivalent factors were found in the sediment from core 1 from Suruí Mangrove, with a predominance of benzo[k]fluoranthene, benzo[a]pyrene, and naphthalene. In cores 3 and 4, collected closer to Guanabara Bay, benzo[a]anthracene and benzo[a]pyrene were also found. The sediment in Suruí Mangrove is functioning as a reservoir of compounds that are carcinogenic to the fauna and flora of the mangrove itself, and to the adjacent waters of Guanabara Bay.

Yangshan Deepwater Harbor, located in the Qiqu Archipelago adjacent to Hangzhou Bay, is the new deepwater harbor of the Port of Shanghai. Its construction, which began in 2002, entails three types of engineering projects: closing a series of inlets, land reclamation, and dredging. After the construction of harbors 1, 2, and 3, these engineering projects caused a series of morphological changes in the area. Because of the serious sedimentation in the harbor area, further construction of the planned harbors has been stopped for the time being. Research on the sedimentation and its causes is urgently needed in order to decide whether to continue construction of more harbors.

In this paper we analyze the morphological changes in the harbor area using bathymetric data collected from 1998 to 2010. Since 2004 bathymetry in the area has been surveyed every year, making it possible to analyze the spatial and temporal variation of sedimentation–erosion in detail. The analyses provide a good insight into how the morphological changes are related to the various projects of the harbor construction and how the changes develop over time. It is shown that in the year immediately after an inlet was closed accretion occurred on both sides of the closure. The sedimentation rates decrease significantly in the following years. Accretion accelerated from 2007 to 2009 but decreased thereafter. The results of the analyses indicate that routine dredging will be necessary to maintain the requisite 15-m depth requirement for berths, but a regular dredging routine is feasible.

For a better understanding of the mechanisms responsible for the observed morphological changes a numerical model based on Delft3D is used to simulate the hydrodynamic and sediment transport processes. The model results provide insights into how the morphological changes are related to the changes in hydrodynamics induced by the closures of the inlets.

Kotzebue Sound comprises a large part of the Northwest Arctic Borough (NAB) shoreline. It has a diverse coastal geomorphology. Natural coastal dynamics and global sea-level rise (SLR) are contributing to changes in the erosion and accretion of beaches. Recently published data from the joint project of the University of Colorado (Institute of Arctic and Alpine Research) and National Park Service (Arctic Network Inventory and Monitoring Program) for the first time makes systematic quantitative analysis of coastal changes along the Northwest Alaskan coast possible.

This study is based on shoreline indicators derived from 112 aerial photographs, spanning more than 50 years, from 1950 to 2003, processed by research staff at the Institute of Arctic and Alpine Research. The images were used in this study to locate and digitize the shoreline indicators for 1950, 1980, and 2003. Integration of Geographic Information Systems (GIS) with National Oceanic and Atmospheric Administration's Digital Ahoreline Analysis System (DSAS) provided quantitative measurements of historical coastal changes. Projections of SLR in the Arctic from climate models and historical erosion data were used to estimate future erosion rates.

The results show mean erosion rates of −0.12 to −0.08 m/yr in the region from 1950 to 2003. The northern and southern shorelines showed erosion between 1950 and 1980, but slight accretion/stabilization between 1980 and 2003. These changes possibly correlate with Aleutian low anomaly variations that affected the climate in the area of study. On the basis of the predictions of SLR in the Arctic for 2000–2049 and 2050–2100, mean erosion rates may increase to 0.6–1.65 m/yr. This would translate into an approximately 70–1000-m retreat of the shore, depending on its slope, composition, and geomorphologic type. These results help to assess coastal vulnerability and can contribute to regional planning efforts.

The Laguna Madre of Mexico is the second biggest hypersaline coastal lagoon from the Gulf of Mexico, and supports the most important artisanal shrimp fishery in the country. The population size structure of penaeids from this artisanal fishery was examined, analyzing temporal and interspecific variations. The results indicate that the shrimp fishery in Laguna Madre is supported by three penaeid species (Farfantepenaeus aztecus, F. duorarum, and Litopenaeus setiferus); the consistent presence of F. aztecus and F. duorarum caught throughout the year contrasted with the scarce occurrence of L. setiferus, which exhibited significant fluctuations in its relative contribution to shrimp catches. Significant differences in monthly mean size were observed for the three species. Larger individuals were caught in colder months (November–March); however, the body condition of shrimp was higher in warmer months (April–October). A negative relationship between shrimp size and water temperature was found, which could suggest differences in size at emigration according to temperature fluctuations.

Spatial variability in the structure of a population and in the reproductive traits of the narrow endemic coastal plant thorny knapweed (Centaurea horrida; Asteraceae) was estimated. Variations in the distribution of individuals and reproductive effort were described and quantified at the per-site scale (3 sites, less than 30 kilometers apart) for two habitats (cliff face and cliff plateau) to provide a basis for further investigations of the factors affecting C. horrida performance and to provide information necessary for an effective conservation of this species. Centaurea horrida was considerably more abundant at one site, especially in the cliff plateau, in the contribution of adults. Estimates of spatial variance for each life stage at both habitats revealed that, on the cliff plateau, a much greater variability was found at the per-site scale for classes of saplings and adults of middle size, whereas in the cliff face local (among replicates), spatial variance was higher for all comparisons. For all the reproductive traits considered, variation at the scale of the site in the two habitats was extremely low, whereas it was much more important among replicates, indicating that other determinants rather than recruitment are likely responsible for the heterogeneity in the abundance of adults across sites. Overall, these results suggested that, on cliff plateaus, different processes operate on the C. horrida population structure at the three sites. Consequently, site-specific management needs to be addressed. However, we believe that effective management strategies can only be proposed based on manipulative experiments that highlight the role of the major determinants of spatial patterns.

Most existing studies of beach replenishments make approximations or use rules-of-thumb for the cost of the volume of material applied or the cost per length of shoreline. Using published historical data from the US Atlantic coast, we develop a statistical model of the costs of beach replenishment episodes. The model can be used to evaluate the costs of replenishment as a function of the volume of material, the beach length, the episode location, the year, the type of episode, and the source of funding. Although it has been observed that beach replenishment activities are small and declining in number in some areas, such as in New England, we expect that future coastal erosion expected from changes in sea levels as exacerbated by storm events eventually may lead to increased attention to the use of beach replenishment as a “soft” structural response. It is critical for coastal planners to compare sound estimates of the costs of soft structures to the costs of alternative responses, including hard structures, retreat, and abandonment.