Holgate, S.J.; Matthews, A.; Woodworth, P.L.; Rickards, L.J.; Tamisiea, M.E.; Bradshaw, E.; Foden, P.R.; Gordon, K.M.; Jevrejeva, S., and Pugh, J., 2013. New data systems and products at the Permanent Service for Mean Sea Level.

Sea-level rise remains one of the most pressing societal concerns relating to climate change. A significant proportion of the global population, including many of the world's large cities, are located close to the coast in potentially vulnerable regions such as river deltas. The Permanent Service for Mean Sea Level (PSMSL) continues to evolve and provide global coastal sea-level information and products that help to develop our understanding of sea-level and land motion processes. Its work aids a range of scientific research, not only in long-term change, but also in the measurement and understanding of higher frequency variability such as storm surges and tsunamis. The PSMSL has changed considerably over the past 10 years, and the aim of this paper is to update the community about these changes as well as provide an overview of our continuing work.

Dusek, G. and Seim, H., 2013. Rip current intensity estimates from lifeguard observations.

Lifeguard observations of rip intensity are utilized as an alternative to rip current rescue data to determine the influence of the wave field on rip current activity. Daily rip current intensity observations were made by Kill Devil Hills Ocean Rescue on the Outer Banks of North Carolina over two summers. The daily observations were made at up to 19 alongshore locations over 7.5 km of beach and compared to local wave field observations. The lifeguard intensity observations compare favorably to rip current rescue data when rescues occur; however, rip intensity observations offer significant advantages over rip rescue data: (1) Rip current intensity observations are a continuous data record and provide data even when bathers are not present, and (2) lifeguard observations provide an estimate of rip current intensity, while rescue data only indicate rip current occurrence. Results of this study generally compare favorably to previous research and to expected rip current dynamics. Rip intensity is compared to observed wave spectral statistics (significant wave height, mean direction, peak period, and directional spread) at 12-m depth and to wave height and direction refracted and shoaled to just outside the surf zone to provide a more dynamically relevant comparison. Rip intensity increases with significant wave height (at a threshold value of 0.7 m), wave directions closer to shore normal, and narrower directional spread. The results suggest that wave height determines a baseline intensity level, which is then modulated depending on the direction and spread. No relationship was found between rip intensity and peak period. Rip intensity is analyzed with wave spectral components (wind sea, swell, and multiple swells) and generally yields similar results to the analysis of the bulk spectral measurements.

Benedet, L.; Finkl, C.W., and Dobrochinski, J.P.H., 2013. Optimization of nearshore dredge pit design to reduce impacts on adjacent beaches.

The magnitude of the effects of nearshore dredge pits on adjacent beaches depends on a range of parameters, including seabed geomorphology, local wave climate, sediment supply, and pit design characteristics (e.g. distance offshore, depth of cut, cross-shore and alongshore extents, shape of pit). Delft3D, a morphological model developed by Deltares, was used to investigate relationships between dredge pit design parameters and impacts on adjacent beaches. The purpose of this study was to identify design parameters that affected the magnitude of dredge pit effects on adjacent beaches. An ancillary purpose was to develop a scientific basis for dredge pit design recommendations for beach restoration and other sediment needs of coastal infrastructure projects. Dredge pit design sensitivity tests were conducted using Delft3D. A schematic model was constructed using shore-parallel contours and tests for a single-wave condition and for an annual wave climate. The depth of the cut and the cross-shore length of the dredge pits greatly influenced the magnitude of the dredge pit impacts on the adjacent beaches. The distance of the borrow pits from the shore influenced the magnitude and location of the impacts (because of the oblique wave incidence). An inverse relationship was verified between the water depth where the borrow was located and the magnitude of its impacts on adjacent beaches. Dredge pit impacts on adjacent beaches can be reduced significantly by designing narrow, elongated parabathic pits with have a shallow cut depth. Depth of cut increments had pronounced effects in shallow water (2–6 m), but in water depths greater than 8 m, gradual depths of cut increments of 2 m did not significantly affect its impact on adjacent beaches. Results of this study indicate that the effects of dredge pits on adjacent beaches can be reduced by half by adopting optimal pit designs while maintaining the same dredging volume.

Schwab, W.C.; Baldwin, W.E.; Hapke, C.J.; Lentz, E.E.; Gayes, P.T.; Denny, J.F.; List, J.H., and Warner, J.C., 2013. Geologic evidence for onshore sediment transport from the inner continental shelf: Fire Island, New York.

Sediment budget analyses along the south shore of Fire Island, New York, have been conducted and debated in the scientific and coastal engineering literature for decades. It is well documented that a primary component of sediment transport in this system is directed alongshore from E to W, but discrepancies in volumetric sediment budget calculations remain. An additional quantity of sand, averaging about 200,000 m³/y is required to explain the growth of the western segment of the barrier island, a prograding spit. Littoral sediment derived from updrift erosion of the coast, addition of beach nourishment fill, and onshore transport of inner continental shelf, shoreface sediments, or both have all been proposed as potential sources of the additional sediment needed to balance the sediment budget deficit. Analysis of high-resolution seafloor mapping data collected in 2011, including seismic reflection profiles and inteferometric sonar acoustic backscatter and swath bathymetry; comparison with seafloor mapping data collected in 1996–1997; and shoreline change analysis from 1933 to 2011 support previous suggestions that the inner-shelf Holocene sedimentary deposit is a likely source to resolve this sediment budget discrepancy.

Ford, M.R.; Becker, J.M., and Merrifield, M.A., 2013. Reef Flat wave processes and excavation pits: observations and implications for Majuro Atoll, Marshall Islands.

An experimental deployment of pressure sensors was undertaken to assess the impact of reef flat excavation pits on wave processes at Majuro Atoll, Marshall Islands. Experiments were undertaken on two sections of an 80-m-wide fringing reef flat, one modified by the excavation of a 17-m wide, 4- to 5-m deep pit and the other an unmodified reef flat of comparable width, topography, and incident wave energy. A wave-driven inundation event during the experiment led to minor amounts of debris overwashing the road surface. The event was associated with southerly swell that was normally incident to the study site at high tide, resulting in enhanced shoreline energy in both the sea and swell and the infragravity frequency bands. The shoreline with the excavation pit received slightly smaller wave heights (∼8%) for all wave conditions, including the overwash event, compared to the unmodified shoreline. The statistically significant difference is largely a result of a decrease in infragravity wave energy over and shoreward of the pit that compensates for a weak increase in sea and swell energy. The influence on infragravity energy levels is likely to depend on the pit geometry and position, as well as the wave forcing; hence, not all pits are likely to lead to net wave energy dissipation. Implications of the findings are discussed with respect to the impacts of reef flat excavation on a highly developed, urbanised atoll.

Quan, S.; Kvitek, R.; Smith, D., and Griggs, G. 2013, Using vessel-based LIDAR to quantify coastal erosion during El Niño and inter-El Niño periods in Monterey Bay, California.

Vessel-based light detection and ranging (LIDAR) was employed to collect coastal topography data and to quantify the rates of erosion and spatial distribution of coastal retreat around Monterey Bay, California during the 2008–09 (non-El Niño) and 2009–10 El Niño. These data were compared with pre/post-El Niño LIDAR data from 1997–98 to assess shoreline change and to test the following hypotheses: (1) that broad-scale (km) spatial distribution of erosion rates is positively correlated with wave energy, and (2) that fine-scale erosion hot spots (segments of the coastline exhibiting considerably higher rates of erosion than adjacent areas) shift at predictable alongshore wavelengths between consecutive El Niño and inter-El Niño periods. Broad-scale erosion was found to be significantly higher during the 2009–10 El Niño vs. the 2008–09 non-El Niño period in both the south (1.8 m vs. 0.1 m average) and north bays (0.5 m vs. 0.0 m average). The broad-scale distribution of erosion rates during the 2009–10 El Niño was positively correlated with wave energy. In southern Monterey Bay, erosion rates increased along a wave energy gradient from south to north, whereas erosion and wave energy were both focused and highest at a single location in the northern bay. Fine-scale erosion hot spots were found to occur during the 1997–98 and 2009–10 El Niño and the 1998–08 inter-El Niño period. These hot spots were found to be significantly correlated at −160 m during the 1997–98 El Niño to 1998–2009 inter-El Niño periods and 100 m during the 1998–2009 inter-El Niño to 2009–10 El Niño periods in southern Monterey Bay. Hot spots that occurred during one El Niño or inter-El Niño period shifted spatially alongshore during the subsequent El Niño or inter-El Niño period. Vessel-based LIDAR proved to be effective for detecting coastal change at high spatial resolutions and revealing fine-scale patterns of shoreline retreat.

Lee, Y.G.; Kim, S.; Jeong, D.U.; Kim, J.K., and Woo, H.J., 2013. Effects of heavy rainfall on sedimentation in the tidal salt marsh of Suncheon Bay, South Korea.

Tide observations, geographic surveys, sediment composition, and sediment accretion rate monitoring were conducted to investigate the relationship between general pattern changes and control factors of the accretion rate at 10 localities of the tidal salt marsh of Suncheon Bay over 2 years (June 2007–May 2009). The substrate sediments of the tidal salt marshes that are distributed between the mean sea level and the high water of ordinary spring tide are mainly composed of silt (37.98%) and clay (60.45%) and have a high average annual accretion rate of 28.88 mm/y. The high substrate sedimentation of tidal salt marshes is caused by: (1) a high concentrated suspended sediment supply from the tidal flat; (2) considerable marsh grass vegetation; (3) undeveloped tidal salt marsh creek; and (4) marsh elevation distributed between the mean sea level and the high water of ordinary spring tide. The variation in patterns of the average monthly accretion rate can be divided into three stages: the low stage (June 2007 to February 2008) was the period of lowest accretion rate over 2 years and consistently measured between 5.35 mm and 12.40 mm, averaging out to 8.89 mm that period. The recovery stage (March 2008 to October 2008) was a period of rapid increase in accretion rate and measured from 14.93 mm to 49.47 mm with an average of 33.02 mm. The high stage (November 2008 to May 2009) was a period of high deposition in accretion rate, and measured between 46.67 mm and 53.38 mm, averaging to 49.83 mm. These three stages were formed and changed by heavy rainfall brought about by typhoons in the summer season of Korea and undeveloped tidal salt-marsh creek system. It was confirmed that heavy rainfall may significantly alter the sediment flux within the marsh system in this study.

Warrick, J.A., 2013. Dispersal of fine sediment in nearshore coastal waters.

Fine sediment (silt and clay) plays an important role in the physical, ecological, and environmental conditions of coastal systems, yet little is known about the dispersal and fate of fine sediment across coastal margin settings outside of river mouths. Here I provide simple physical scaling and detailed monitoring of a beach nourishment project near Imperial Beach, California, with a high portion of fines (∼40% silt and clay by weight). These results provide insights into the pathways and residence times of fine sediment transport across a wave-dominated coastal margin. Monitoring of the project used physical, optical, acoustic, and remote sensing techniques to track the fine portion of the nourishment sediment. The initial transport of fine sediment from the beach was influenced strongly by longshore currents of the surf zone that were established in response to the approach angles of the waves. The mean residence time of fine sediment in the surf zone—once it was suspended—was approximately 1 hour, and rapid decreases in surf zone fine sediment concentrations along the beach resulted from mixing and offshore transport in turbid rip heads. For example, during a day with oblique wave directions and surf zone longshore currents of approximately 25 cm/s, the offshore losses of fine sediment in rips resulted in a 95% reduction in alongshore surf zone fine sediment flux within 1 km of the nourishment site. However, because of the direct placement of nourishment sediment on the beach, fine suspended-sediment concentrations in the swash zone remained elevated for several days after nourishment, while fine sediment was winnowed from the beach. Once offshore of the surf zone, fine sediment settled downward in the water column and was observed to transport along and across the inner shelf. Vertically sheared currents influenced the directions and rates of fine sediment transport on the shelf. Sedimentation of fine sediment was greatest on the seafloor directly offshore of the nourishment site. However, a mass balance of sediment suggests that the majority of the fine sediment moved far away (over 2 km) from the nourishment site or to water depths greater than 10 m, where fine sediment represents a substantial portion of the bed material. Thus, the fate of fine sediment in nearshore waters was influenced strongly by wave conditions, surf zone and rip current transport, and the vertical density and flow conditions of coastal waters.

Dong, S.; Tao, S.; Lei, S., and Guedes Soares, C., 2013. Parameter estimation of the maximum entropy distribution of significant wave height.

This paper compares the estimation of the four parameters of the maximum entropy distribution by different methods and applies them in two test cases with significantly different characteristics of variability. The moment method and the maximum likelihood method for the maximum entropy distribution with four parameters are formulated in the paper. These methods are compared with the moment method for the maximum entropy distribution with three parameters and an empirical curve-fitting method, both of which have been used earlier. These four estimation methods are applied to two test cases. One consists of hindcast wave heights at Weizhoudao hydrological station in the northern area of the South China Sea, which is subject to typhoon type of events. The other data set is hindcast wave heights at a location in the North Atlantic Ocean, which is subject to frequent storm weather. The maximum likelihood and the empirical methods appear to provide the most consistent results.

Romine, B.M. and Fletcher, C.H., 2013. A summary of historical shoreline changes on beaches of Kauai, Oahu, and Maui, Hawaii.

Shoreline change was measured along the beaches of Kauai, Oahu, and Maui (Hawaii) using historical shorelines digitized from aerial photographs and survey charts for the U.S. Geological Survey's National Assessment of Shoreline Change. To our knowledge, this is the most comprehensive report on shoreline change throughout Hawaii and supplements the limited data on beach changes in carbonate reef–dominated systems. Trends in long-term (early 1900s–present) and short-term (mid-1940s–present) shoreline change were calculated at regular intervals (20 m) along the shore using weighted linear regression. Erosion dominated the shoreline change in Hawaii, with 70% of beaches being erosional (long-term), including 9% (21 km) that was completely lost to erosion (e.g., seawalls), and an average shoreline change rate of −0.11 ± 0.01 m/y. Short-term results were somewhat less erosional (63% erosional, average change rate of −0.06 ± 0.01 m/y). Maui, Hawaii, beaches were the most erosional of the three islands with 85% of the beaches erosional, including 11% lost, and an average change rate of −0.17 ± 0.01 m/y. Seventy-one percent of Kauai, Hawaii, beaches were erosional, including 8% lost, with an average change rate of −0.11 ± 0.01 m/y. Most (60%) of the Oahu, Hawaii, beaches were erosional, including 8% lost, with an average change rate of −0.06 ± 0.01 m/y. Short-term results for Maui, Hawaii, and Oahu, Hawaii, were roughly the same as those found in the long term. Short-term analysis for Kauai, Hawaii, was less conclusive with an accretional average rate, but most of the beaches were erosional. Spatially, shoreline change is highly variable along the Hawaii beaches (length scales of hundreds of meters). Areas of chronic erosion were identified on all sides of the islands.

Kobayashi, N.; Pietropaolo, J.A., and Melby, J.A., 2013. Wave transformation and runup on dikes and gentle slopes.

Coastal flood-risk mapping requires the prediction of wave runup and overtopping of dikes and beaches. The cross-shore numerical model CSHORE is adjusted to predict irregular wave runup on impermeable dikes. The model is compared with 137 wave runup tests and 97 wave overtopping tests. The seaward boundary of the computation is taken at the location where wave setup is negligible. The spectral period and peak period at this boundary location are specified as input. The model predicts the measured cross-shore variation of the spectral significant wave height on the barred and sloping beaches in front of the dikes. The measured 2% and 1% exceedence runup heights are predicted within errors of about 20% for the spectral period used as input to CSHORE. The model predicts the threshold of wave overtopping, but the minor wave overtopping rates can be predicted only within a factor of 10. The model is also compared with 120 tests for wave runup on gentle uniform slopes as well as wave runup data on natural beaches in order to assess the utility of the numerical model for coastal flood-risk mapping on sand beaches.

Lim, H.S.; MatJafri, M.Z.; Abdullah, K., and Asadpour, R., 2013. A two-band algorithm for total suspended solid concentration mapping using THEOS data.

Environmental monitoring through the method of traditional ship sampling is time consuming and requires a high survey cost. This study was carried out to investigate the relationship between total suspended solids (TSS) and satellite THEOS data by using a calibrated algorithm. The study area is the seawater region around Penang Island, Malaysia. Water-quality TSS values were collected simultaneously during the acquisition of the satellite imagery and later analyzed in the laboratory. The digital numbers of the corresponding TSS measurements were extracted and converted into reflectance values for algorithm regression. The two-band algorithm used here is based on the reflectance model, which is a function of the inherent optical properties of water, and this in turn can be related to the concentration of its constituents. The developed algorithm was used to correlate the digital signal and the TSS values. The generated algorithm was developed for two visible wavelengths, red and blue for this study. The digital numbers corresponding to the sea truth locations were extracted for algorithm calibration. Based on the values of the correlation coefficient squares (R²) and root-mean-square deviation (RMS), the proposed algorithm is considered superior. A water-quality image was generated using the multispectral data set and the proposed calibrated TSS algorithm. Finally, the generated TSS map was geometrically corrected to produce a geocoded map. Filtering was performed to the generated map to remove random noise, and it was color-coded for visual interpretation. This study indicates that the TSS algorithm developed from optical properties is a promising TSS model for high-accuracy TSS mapping using satellite data.

Horne, P.; Suteanu, C.; van Proosdij, D., and Baker, G., 2013. Elevation-dependent multiscale analysis of a complex intertidal zone.

Coastal geomorphology is the result of many complex interacting processes operating over a range of scales in space, and multiscale analysis on relevant scale intervals can help link form with process. Numerous studies focus on lines resulting from the intersection of a plane at a certain elevation with the three-dimensional landscape. However, in most cases, the reason for the choice of the actual elevation is not mentioned, nor at times is the value of the selected elevation even specified. Such an approach relies on the assumption that one studies an isotropic, self-affine pattern for which the irregularity is independent from elevation. The present study questions this assumption by applying fractal analysis not to one, but rather to a series of different elevations relating to tidal stages. The research takes place in a macrotidal estuary, in the Upper Bay of Fundy, Canada, where diurnal tides exceed 14 m. The topography of Avon Estuary is influenced by complex interacting factors, including hydrodynamic and sedimentary processes, vegetation, and ice formations, as well as by anthropogenic structures. The area–perimeter analysis method was applied to 0.5-m contour intervals on a digital elevation model derived from a light detection and ranging survey conducted at low tide. The results show a pronounced and coherent dependence of the fractal dimension on elevation. Fractal dimensions between 1.2 and 1.17 are generally associated with sand sediment transport and bedform development at elevation ranges from −5 to −1 m Canadian Geodetic vertical datum of 1928. Between D values 1.7 and 1.12 at elevations from −0.5 to 2.5 m CGVD28, vertical accretion processes dominate with bank edge erosion. D values continue to increase above elevations greater than 3 m as vegetation becomes established and stabilizes the intricate tidal creek networks. We show that this approach supports a better understanding of the interacting processes that dominate the area on different ranges of scale.

Stanley, J.-D. and Corwin, K.A., 2013. Measuring strata thicknesses in cores to assess recent sediment compaction and subsidence of Egypt's Nile Delta coastal margin.

Coastal flood risk in California is concentrated around urbanized embayments that are protected by infrastructure, such as levees, pumps, and flood walls, which pose a challenge to accurate flood prediction. A capability to predict coastal urban flooding at the parcel-scale (individual home or street) from high ocean levels (extreme high tides) is shown here by coupling a regional ocean forecasting system to an embayment-scale hydrodynamic model that incorporates detailed information about flood defenses. A unique flooding data set affords the rare opportunity to validate model predictions and allows us to identify model data that are essential for accurate forecasting. In particular, results show that flood defense height data are critical, and here, that information is supplied by a Real Time Kinematic Global Positioning System (RTK-GPS) survey, which yields ca. 1-cm, vertical root mean-squared error accuracy. Bathymetry surveys and aerial Light Detection and Ranging (LIDAR) data characterizing the embayment also prove essential. Moreover, hydrodynamic modeling of flood inundation is shown to significantly improve on planar surface models, which overestimate inundation, particularly when manipulated to account for run-up in a simplistic way. This is attributed to the transient nature of overtopping flows and motivates the need for dynamic, spatially-distributed overtopping models that are tailored to the urban environment.

This study develops a method to determine compaction and subsidence of Holocene fluviomarine sections along Egypt's northern Nile Delta coastal margin based on variations of strata thickness with depth. Thicknesses of 3183 oxidized layers in 85 long cores (10 to 45 m) are examined to determine the nature of down-section and spatial patterns. The thickest layers are at depths of 1 to 2 m (dating to <1000 y BP) and become significantly reduced within the next meter due to (1) rapid expulsion of interstitial pore water from overburden compression of sediment and (2) evaporation in near-surface deposits in this hyperarid setting. Thicknesses decrease more irregularly to depths of 5 to 6 m and then more gently to the base of the sections. The more gradual compaction of strata at mid- and lower-core depths accounts for more than 50% of total Holocene compaction. The derivatives of regression curves determine the strata thickness reduction rate, which is treated as a proxy for compaction rate. Average compaction rates for Holocene sections vary along the approximately 225-km-long coastal margin: about 8.4 mm/y in the NE, about 7.7 mm/y in the NC, and about 3.7 mm/y in the NW sectors. These rates, somewhat higher than those previously proposed for this delta, are within the range for land subsidence obtained from recent satellite surveys. The interaction of natural factors, such as moderate to high compaction rates and rising global sea level, with human activities, especially those reducing sediment supplied to the lower delta, presents serious concerns for the delta's future. Without emplacement of a continuous network of protective structures along the coast, a marked landward retreat of about 30 km by the Mediterranean coast is projected in little more than a century, resulting in submergence and loss of agricultural and wetland terrains vital to Egypt's rapidly expanding population.

Obiefuna, J.N.; Nwilo, P.C.; Atagbaza, A.O., and Okolie, C.J., 2013. Land cover dynamics associated with the spatial changes in the wetlands of Lagos/Lekki Lagoon system of Lagos, Nigeria.

Urban sprawl is one of the severe land use/land cover (LULC) change agents, especially in rapidly urbanizing developing countries such as Nigeria. Land use/land cover is among the key drivers of environmental change as it leads to dramatic changes in both landscape patterns and ecosystem functions. Lagos metropolis, the nation's economic nerve center, is on a low-lying coastal landscape endowed with lagoons, wetlands, and other ecological assets. The Lagos/Lekki Lagoon system, with its catchments and wetlands, constitute about 71% of the state. With rapid urbanization and intense development pressure, some of the fringing wetlands and other land cover in the area have been converted to urban landscape. Just like the wetlands, the precise nature of these land cover changes is comprehensively unknown. In this ongoing study, land cover dynamics linked to the spatial changes in the wetlands fringing these lagoons are also comprehensively assessed. With low topography, high energy, and erosive coastlines, the extent of coastal erosion (1985–2009) in the area is assessed with remote sensing data and geographic information system (GIS) using topographic maps as baseline data. ENVI software is deployed for the processing of Landsat imageries, and unsupervised classification is used for image classification. The objective is to establish the locations and magnitude of the land cover dynamics between 1984 and 2006, ultimately leading to implications for flood risk on affected areas. Results show that as swamps decreased from 344.75 km² to 165.37 km² and mangroves decreased from 88.51 km² to 19.95 km², both between 1984 and 2006, built-up areas increased from 48.97 km² to 282.78 km² at 10.61 km²/y; water body decreased from 685.58 km² to 654.98 km² at −0.16 km²/y; bare land increased from 24.32 km² to 72.73 km² at 2.2 km²/y; and vegetation decreased marginally from 1369.15 km² to 1361.08 km² at −0.37 km²/y all between 1984 and 2006. Evidently most of the growth in built-up areas occurred in previous wetland areas and some vegetated areas. Most of the increase in built-up area occurred in the Eti-osa Local Government Area (LGA) and then in the Kosofe LGA. The decrease in the water body is attributable to anthropogenic action of reclamation and accretion arising from island formation on the Lekki Lagoon. Some of the consequences of the land cover (LC) dynamics are briefly highlighted.

Álvarez-Molina, L.L.; Martinez, M.L.; Lithgow, D.; Mendoza-González, G.; Flores, P.; Ortíz-García, S., and Moreno-Casasola, P., 2013. Biological flora of coastal dunes and wetlands: Palafoxia lindenii A. Gray.

Palafoxia lindenii A. Gray is a short shrub endemic to the coastal dunes located in the central region of the Gulf of Mexico, mainly in the state of Veracruz. In this study we assembled information on this species and described the taxonomy and variation of the species, its phylogeny and geographical distribution, plant communities, physiological ecology, population biology, reproduction, geomorphological interactions, biotic interactions, response to water levels, and economic importance. The genus Palafoxia includes 12 species, all of them native to North America. The size of seeds varies widely along the geographic distribution of the species, which is most abundant in hot but not very humid sites. This species produces seeds all year long, although individuals do not reproduce simultaneously. Seeds germinating at the onset of the rainy season have a better survival rate than late cohorts. It is one of the first mobile dune colonizers. Similar to other dune species, it not only tolerates burial by sand, but grows better after burial and because of this it is a good foredune builder and forms trailing-ridges. It has a strong association with mycorrhizal fungi, which enhance growth and survival, but only when the plant is not under stress. Because of its dune-forming ability, the plant is important for the beach and coastal dunes as well as for the protection of coastal infrastructure. The leaves contain flavonoids with important antioxidative effects that benefit human health. Development and tourism along the coast are rapidly reducing the habitat of this species.

Palafoxia lindenii (A. Gray) es un arbusto endémico de las dunas costeras de la región central del Golfo de México, en el estado de Veracruz. En este estudio hemos recopilado información sobre esta especie y describimos su taxonomía y variación, filogenia y distribución geográfica, las comunidades que habita, su ecología fisiológica, biología de poblaciones, reproducción, interacciones geomorfológicas, interacciones bióticas, respuesta a los niveles de agua y su importancia económica. El género Palafoxia incluye 12 especies, todas ellas nativas del norte del continente Americano. Las semillas varían ampliamente a lo largo de la distribución geográfica de la especie, que es más abundante en sitios cálidos y no muy húmedos. Esta especie produce semillas todo el año, aunque los individuos no se reproducen al mismo tiempo. Las semillas que germinan en el inicio de la temporada de lluvias tienen una mejor tasa de supervivencia que las cohortes finales. Es una de las primeras plantas colonizadoras en dunas móviles. Al igual que otras especies de dunas, no sólo tolera el enterramiento por arena, también crece mejor en esas condiciones y debido a eso, esta planta es una buena especie formadora de dunas frontales. Tiene una fuerte asociación con hongos micorrícicos, que mejora el crecimiento y la supervivencia, cuando la planta no está bajo estrés. Debido a su capacidad como planta pionera para la formación de dunas, es una especie importante para la protección costera. Las hojas contienen flavonoides, con efectos importantes sobre la salud humana. El desarrollo y turismo a lo largo de la costa están reduciendo rápidamente el hábitat de esta especie.

Cappietti, L.; Sherman, D.J., and Ellis, J.T., 2013. Wave transmission and water setup behind an emergent rubblemound breakwater.

Wave transmission and water setup landward of emergent detached breakwaters play a major role in altering nearshore hydrodynamics, circulation, and morphodynamics and influencing the safety of recreational bathers. These phenomena have been extensively studied by means of small-scale laboratory experiments and numerical simulation, but field measurements have been extremely limited. In this work, wave transmission and setup were measured landward of a detached, emergent rubble-mound breakwater at Marina di Pisa, Italy. Water-surface elevations were measured with pressure transducers onshore and offshore of the breakwater. Measurements were made for 14 hours during a storm with significant wave heights up to 3.5 m and mean periods of 8.5 s. In the present work, the data were used to quantify and develop statistical relationships describing wave transmission and water setup and to evaluate the performance of empirical models of transmission and setup for emergent breakwaters. We found that the incident wave height explained (statistically) 94% of the variability in wave transmission and 96% of the variability in setup for the Marina di Pisa breakwater. There was a 99% coefficient of determination when explaining variation in setup using incident wave height and transmissivity. Of the empirical models we tested, those that best predicted observed wave transmission landward of the breakwater had root mean square (RMS) errors of 33%. The best available models to predict observed setup had RMS errors of 66%.

Lonard, R.I.; Judd, F.W., and Stalter, R., 2013. The biological flora of coastal dunes and wetlands: Sporobolus virginicus (C. Linnaeus) K. Kunth.

Sporobolus virginicus (C. Linnaeus) K. Kunth is a warm temperate, subtropical, and pantropical rhizomatous grass. It is an important species in foredunes, primary dunes, interdunal depressions, salt marshes, brackish marshes, and on the margins of salt pans where it is often a dominant species. Sporobolus virginicus is a euhalophyte that tolerates soluble salts ranging from 3 to 94 parts per thousand, and where the pH varies from 6 to 8.8. This species is freeze sensitive at −2.5°C with no hardening capacity. Also known as seashore dropseed, seedlings are sensitive to tidal inundation, but established plants are not affected by waterlogged conditions. The species is important for controlling beach erosion and for stabilizing sandy substrates. Stands of S. virginicus provide food for livestock and wildlife. Herein, we present a review of the biology of this important species.

Chun, J.; Song, G.C., and Ahn, K., 2013. A simple numerical method on the partial reflection and transmission of water waves in the hyperbolic mild-slope equation.

This article presents a new numerical method for the partial reflection and transmission of water waves in the hyperbolic mild-slope equation. When the reflection or transmission coefficients of the breakwater are known, the present numerical method can be used to calculate the partial reflection and transmission around it in a simple manner. This method has been validated through several numerical experiments. The computed results showed that the present model successfully predicted the partial reflection and transmission of the water waves from the breakwater, regardless of the wave periods under the constraint of the reflection coefficient >0.2. Numerical experiments have also been conducted in permeable, semi-infinite breakwater problem with various reflection and transmission coefficients under normal and oblique incident wave conditions. The numerical results were compared with analytic solutions of Yu (1995) and McIver (1999), which were found to be in good agreement between the numerical results and the analytical solutions.

Cowles, G.W., 2013. A block-structured adaptive mesh refinement solver for morphodynamic modeling.

An adaptive solver for two-dimensional horizontal morphodynamic modeling studies is presented. The method employs an established augmented Riemann solver to compute unsteady, two-dimensional flows over arbitrary topography. An Exner equation is used to model the evolution of the bed using several common load formulas. The morphodynamic coupling is stabilized using an upwind approach. The scheme is implemented in a highly scalable block-structured adaptive mesh refinement framework. The resulting solver is well balanced and resolves the dry state while maintaining nonnegative depth. Idealized tests include comparison with exact Riemann solutions for dam break problems and an analytical solution for the migration of a one-dimensional sinusoidal bedform. Practical tests include the migration of a Gaussian perturbation and the evolution of flood and ebb shoals in a tidal inlet. The solver is benchmarked on a modern multiprocessor machine to quantify the scalability of the approach.

Yang, C.; Jiang, C., and Lin, B. 2013. Modelling graded sediment transport and bed evolution in a tidal harbour.

This paper presents the development of a sediment transport model to predict the bed evolution processes in estuarine and coastal waters. The model is based on an existing hydrodynamic and sediment transport model, with significant refinements being made to enhance its capability for simulating the transport of graded sediments under nonequilibrium conditions. A multifraction sediment transport model has been developed to replace the existing single-fraction model. The sediment mixture is divided into several fractions according to the grain size. For each fraction, the particle size is considered to be uniform, and its transport form, either as suspended load or bed load, is determined by the magnitude of a suspension index. A bed evolution model is developed to simulate the processes of bed level change and sediment grain size sorting. The model is applied to a laboratory model harbour, for which measurements of tidal currents and bed level inside the harbour are available. The water level, velocity distributions, and bed level changes predicted by the numerical model are compared with the laboratory data. Comparisons are also made between predictions made by the fractional model and the single-size model. The effect of bed sediment size change on the erosion process has been investigated.