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Aguiar, V. M. C., Abuchacra, P. F. F., Baptista Neto, J. A., 2013. Biogeochemistry of Jurujuba Sound, concerning phosphorus dynamics, Rio de Janeiro, Brazil.
Guanabara Bay stands out as one of the most polluted coastal areas of Brazil, highly eutrophicated, surrounded by industries and a non planned urbanized area. The concentrations of nutrients in this area vary greatly, generally presenting higher levels in the inner portions. Jurujuba is a small sound located at the eastern board of Guanabara Bay and comprises a local fishing community, which makes it economically important. The present study proposes to evaluate the trophic levels of this area not only through the water column, but also through the composition of sedimentary organic matter. Results revealed unquestionable effects of eutrophication as hypoxia in bottom waters, and phytoplankton blooms in the surface, with chlorophyll-a values up to 40.58 μg.L−1, and oxygen contents as low as 0.86 mg.L−1. Surprisingly, concentrations of dissolved nutrients were mostly characteristic of oligotrophic environments. Dissolved inorganic phosphorus varied between 0.09 and 3.98 μM. Ammonium varied between 0.78 and 3.84 μM. In the sediments, inorganic phosphorus (IP) varied between 1.61 and 15.80 μmol.g−1 and organic phosphorus (OP) presented maximum and minimum values of 10.06 and 1.52 μmol.g−1, respectively. Biopolymers characterized the sediments as hypertrophic, with high levels of proteins (PRT) and carbohydrates (CHO), therefore, confirming the conditions of eutrophication in this environment, despite the low levels of dissolved nutrients. PRT:CHO<1 characterized Jurujuba sound as a detrital-heterotrophic system, corroborating the contents of organic matter as high as 28.78%.
Nascimento-Filho, G.A.; Montes, M. de J.F.; Gaspar, F.L.; Paulo, J.G.; Feitosa, F.A. Eutrophication and water quality in a tropical estuary.
The use of indexes and trophic state models are gaining importance in evaluating the degree of anthropogenic influence on estuarine eutrophication and the impact on coastal and adjacent areas. A TRIX index and an ASSETS model were used to evaluate the level of eutrophication in the estuary of Suape Industrial Port Complex. The values for the TRIX trophic state multivariate index revealed the increase towards the upper estuary, going from 2.26 at high tide at station 1 (low estuary), demonstrating a medium trophic state and good water quality, to 6.43 at low tide at station 3 (upper estuary), showing an elevated trophic state and poor water quality, where continental drainage is accelerating the eutrophication process in the environment. In the evaluation generated by the ASSETS eutrophication model, the estuary eutrophication level was considered to be moderate, with Overall Human Influence considered Low, General Eutrophication Conditions also considered Low. Finally, the Determination of Future Outlook showed an unchanged expression and perspectives for slow degradation. The comparison between the index and model showed some similarities, in general, TRIX quantified the Massangana river estuary at a level medium of eutrophication and ASSETS qualified it as moderate.
Archetti, R., Mancini, M.L. 2013. Freshwater discharge by estuarine transition flow near Cesenatico (Italy)
The freshwater dispersion plume in the sea is described in the paper with the aim of a 3D numerical model and with the validation of field campaigns carried out in different conditions. The investigated area regards the coastal zone near Cesenatico (Adriatic Sea, Italy). The fresh water is dispersed by the Canal Harbor mouth in open sea. Surface lagrangian paths, acquired by innovative properly designed drifters, have allowed the validation of the hydrodynamic model. During the first campaign the hydrodynamic is driven only by the tidal oscillation and during the second also by surface wind, the tested conditions were, so, different and interesting for the understanding of the complex dynamic. The presented study can represent a tool useful for the water quality coastal management.
Azevedo, A., Sousa, A.I., Lencart e Silva, J.D., Dias, J.M. and Lillebø, A.I., 2013. Application of the generic DPSIR framework to seagrass communities of Ria de Aveiro: a better understanding of this coastal lagoon
Seagrasses are rooted flowering plants, forming dense and highly productive meadows in transitional and coastal waters, which assure major functions and services contributing to the ecosystems health. However, the increased decline and fragmentation of seagrass meadows lead to the loss of the associated benefits. In Ria de Aveiro coastal lagoon (Portugal), seagrass meadows showed a marked decline during the past three decades. In this context, the DPSIR framework (Drivers-Pressures-State-Impacts-Response) arises as an useful tool for environmental assessments. The objective of this study was to apply the DPSIR conceptual model to the seagrass communities in the Ria de Aveiro lagoon, to identify the main drivers, pressures, state and impacts resulting in its decline. Lastly, it was intended to propose possible management responses towards the maintenance of the functions and services provided by the seagrass communities in the Ria de Aveiro. This framework provided an integrated view of the past-present information considering the background data available. The results obtained by the application of the DPSIR framework to the seagrass communities of Ria de Aveiro lagoon structured the existing data from the point of view of a multiple-effect chain, and it was suggested that seagrasses decline in this coastal system have been mainly due to anthropogenic pressures. In conclusion, this work is a relevant contribution from an ecological-scientific perspective of seagrass meadows in the Ria de Aveiro lagoon, with succinct information potentially useful to be integrated in management tools applied to the overall coastal lagoon.
Azzellino A., Carpani M., Çevirgen S., Giupponi C., Parati P., Ragusa F., Salvetti R. 2013. Managing the nutrient loads of the Venice Lagoon Watershed: are the loads external to the watershed relevant under the WFD River Basin District framework?
Water policy in the EU needs to be increasingly coordinated under the integrated management structure required by Water Framework Directive. In the WFD framework, all river catchments are assigned to administrative River Basin Districts (RBDs) that produce river basin management plans (RBMPs). RBMPs need to define appropriate Program of Measures (PoMs) based on the knowledge of the pressures and impacts affecting the water environments. However, pressures may also be external to the administrative RBDs, and still play a significant role. This study presents the case of the Venice Lagoon Watershed (VLW) and analyses the apportionment of the nutrient loads discharged to the lagoon by apportioning the external and the internal nutrient sources. VLW is included in the River Basin District of the Eastern Alps, although due to the complex framework of legislations and authorities that have managed the watershed to date, it is the object of a separate planning. The source apportionment assessment is assessed at the watershed scale by combining direct measurements and modeling results. The US Soil and Water Assessment Tool is used to simulate the expected improvements due to the application of “within watershed” measures. Model simulations pointed out the significant contribution of the loads external to the watershed, which seriously affect the effectiveness of the “within watershed” PoMs which are revealed largely ineffective if not coordinated with PoMs of boundary RBDs.
Choi, K.Y., Kim, S.H., Hong, G.H., Kim, C.J., 2013. Assessment of the metal contamination and potential toxicity of sediment from artificially closed system port in South Korea.
A study was performed to determine the total and potentially bioavailable heavy metal concentrations in sediments from the Port of Incheon, and the differences in contamination for each pier were identified. Metal enrichment factors (EF) suggested that contamination with Cu, Zn, Cd, Pb, and Hg was occurring at the port. Ni, Cu and Zn concentrations exceeded the effect range low level at most sampling sites according to U.S. NOAA sediment quality guidelines (SQGs). The potential toxicity of metals was determined by 1M HCl extractions. Large portions of Cu, Zn, Cd, and Pb were present as potentially bioavailable fractions (1M HCl extractable fractions) and they were introduced from anthropogenic activities. Principal component analysis (PCA) was performed in order to assess the sources of contamination of the sediment and the influence of anthropogenic activities on sediment quality. Two PCA factors were obtained for identifying the sampling sites affected by anthropogenic activities. Patterns of sediment contamination at each pier were classified, and the results showed that Cu–Zn–Cd–Pb–Hg and Ni were the main components.
Delpeche-Ellmann, N.C., Soomere, T., 2013. Using Lagrangian models to assist in maritime management of Coastal and Marine Protected Areas
Several previous attempts to mitigate current-driven environmental risks to the nearshore via a concealed structure of surface Lagrangian transport have assumed a constant value to the entire nearshore. We extend these attempts towards more realistic accounting for the Coastal and Marine Protected Areas (MPA). We investigate the effects shifting the present fairway would have on the amount of current-driven pollutants the MPA may receive. The Rossby Centre Ocean circulation model, the TRACMASS Lagrangian trajectory model and statistical methods were employed to identify patterns of current-driven transport in the Gulf of Finland, the Baltic Sea, for the period 1987–1991. Pollution point sources were assumed to occur along the fairway. An analysis was made on how much of the pollution travelled to each of the MPA and the time frame involved. The existing fairway passes extremely close to one of the MPA. Shifting the fairway by a small distance to the south leads to a huge decrease in the amount of pollution. However deciding to shift a fairway requires several other factors to be considered, for this may also increase the risk of pollution for other MPAs or be incompatible with the national legislation.
Guebert, F.M., Barletta, M. and Costa, M.F., 2013. Threats to sea turtles in the Western Atlantic: poaching and mortality in small-scale fishery gears.
Interactions between small-scale fishery activities and sea turtles were investigated in coastal fishers' population of the South and Northeast Brazilian coast, Western Atlantic. Data were collected using semi-structured questionnaires (N=418). The presence of four sea turtle species was confirmed in the studied areas: Chelonia mydas, Caretta caretta, Eretmochelys imbricata and Dermochelys coriacea. Adults are commonly seen in the water, and nesting females and hatchlings on beaches, especially at the Northeast region. The presence of the three most easily distinguishable ontogenetic phases (hatchlings, juveniles and adults) confirms the importance of the estuaries and adjacent areas for sea turtles feeding, gathering, nesting, growing and resting grounds. Fishing was considered the most important threat to sea turtles (77%). Gillnets with small mesh sizes (<60 mm) more frequently interact with sea turtles (65%), and mortality was mostly related to gillnets with larger mesh sizes (>60 mm) (100%) (p<0.01). Although poaching is a cultural habit still practiced by many people, fishers did not openly assume it. In addition, most fishers (82%) (p<0.01) do not know that it is possible or how to recover sea turtles drowned in fishing gears. Conservation measures should be adopted by fishers to reduce sea turtle mortality such as monitoring soak gillnets more frequently, avoiding nets with larger mesh sizes and thicker threads, and an awareness campaign to provide recovery procedures for turtles drowning in fishing gears. This would be the basis of the design of desirable mitigation actions enhancing conservation efforts and benefiting marine diversity as a whole.
Ivar do Sul, J.A. and Costa, M.F. Plastic pollution risks in an estuarine conservation unit.
Plastics enter the marine environment mostly from land-based sources, often via estuaries. However, studies related to plastic debris pollution remain rare within these environments. An estuarine beach comprised within a Marine Conservation Unit (MCU) in the Northeast coast of Brazil was studied during one year regarding plastic pollution. Petroleum derived products were >95% of all items, as commonly reported for other coastal and marine habitats. Monthly totals of marine debris presented an average of 10.8±1.63 items.100m−2, much lower than reported in the literature for other estuarine beaches. Three main sources were identified: fisheries, local users and human settlements along the river basin. The most frequent (56%) size category was 11–100cm2, but fragmented items alone were 83% of observed items. The main impact on the estuarine and visiting biota expected is the ingestion of plastic items and fragments, which was corroborated by recent works on estuarine fishes. Interactions with fishing gear are highlighted in the context of this MCU. To protect the traditional livelihoods in the Goiana Estuary, the guarantee of a healthy ecosystem, inclusive free from plastic pollution, must be included in management plans.
Ji, H., Pan, S. and Han, X., 2012. Effect of wastewater discharge on Jiangsu coastal environment, China
To meet the needs of the rapid economic development in the coastal area of Qidong City in Jiangsu Province of China, a new wastewater treatment plant and a reclaimed water plant have been planned. The preliminarily treated wastewater will be discharged to the coastal area in the Yellow Sea near Dayang Port. Due to the complex tidal regime in the area, the impacts of the outfall from the treatment plant can be important for the surrounding marine environment. The present study aims to investigate the impacts of the discharge of the treated wastewater into the Yellow Sea under three operational conditions using the TELEMAC software. The computational domain covers a large coastal area (~2800 km2). TELEMAC2D is used to compute the depth-averaged currents, and the convection and diffusion of the pollutants, namely CODMn and Inorganic Nitrogen, which are treated as the neutral buoyancy tracers, but with temporal decay. The hydrodynamic aspects of the model are calibrated with the field measurements. The model results show a good agreement of the computed water levels and velocities compared with the field measurements. Model applications include the impact studies with the normal operational conditions of both wastewater treatment plant and reclaimed water plant, and two accidental operational conditions with increased discharges of treated and untreated wastewater. The results show that when both plants are operating under normal full capacity conditions, the treated wastewater discharged to the sea poses no threat to the water quality and marine environment under the current regulations. However, when the untreated wastewater is discharged in the sea, it will pose a significant threat to the water quality.
Jun, K.W. and Jang, C.D., 2013. Effects of Salinization of Groundwater along the Western Coast of Korea are Reduced by Artificially Recharging with Freshwater
Climate change, which is becoming an issue throughout the entire world, is also affecting the seawater intrusion aspect of the coastal region of the Korean peninsula. The Korean coast which is surrounded by the three oceans, was used to analyze the trend of seawater intrusion, and the results showed that the west coast of Korea was in a more serious state than the other coasts. Salinization of groundwater by seawater intrusion in coastal areas may cause decreases in crop harvests due to reduced availability of freshwater for irrigation. This research used the groundwater analysis model, the FEMWATER, to analyze the characteristics of the seawater intrusion in the Younggwang region of the west coast. By using the data from the groundwater well, a 3 dimensional model of underground space was set up and a numerical simulation of the effects of the artificial recharging of fresh water in order to reduce the damage of seawater intrusion was carried out.
Virgínia A. Martins, João A. Dias, Lázaro M. Laut, Frederico Sobrinho, José Francisco Santos, Maria Antonieta Rodrigues, Fabrizio Frontalini, Paulo Miranda, Denise Terroso, Sandra Fernández-Fernández, Bruna Ferreira, Cristina Bernardes, Rubens Figueira, Sílvia Sousa, Paula Amaral, Michel Mahiques, Ana Bernabeu, Daniel Rey, Belén Rubio, Fernando Rocha
Martins, V.A., Dias, J.A., Laut, L.M., Sobrinho, F., Santos, J.F., Rodrigues, M. A., Frontalini, F., Miranda, P., Terroso, D., Fernández-Fernández, S., Bernardes, C., Figueira, R., Sousa, S., Amaral, P., Mahiques, M., Bernabeu, A., Rey, D., Rubio, B., and Rocha, F., 2013. Speciation of rare earth elements in surface sediments of Lagoon of Aveiro (N Portugal).
The goal of this work is to determine the distribution of the rare earth elements in the surface sediments in the Ria de Aveiro (N Portugal) coastal lagoon. Concentrations of REE (La, Ce, Nd, Sm) and related elements (Th, Y and Sc) were evaluated by total digestion of sediments in the fine fraction of 33 grab-samples of surface sediments. The same method was followed for Al, Ca, S and Zr, related to terrigenous sources, but also, in the cases of Ca and S, to biogenic and quimiogenic processes. Concentrations of REE and related elements were additionally assessed by a three-step sequential chemical extraction (E1-3) procedure coupled with ICP MS determination. The geochemical results were processed by statistical analysis combining textural and mineralogical data (XRD techniques).
The results show that mobile La, Ce, Nd, Sm and Y are mostly adsorbed by amorphous Mn hydroxide (E3), secondly associate with organic matter (E2) and only in a very small extent are adsorbed on clay mineral structural sheets or associated with carbonates (E1). Thorium and Sc are almost exclusively linked with E2. Ytrium shows a very high percentage of availability, whilst Ce, La, Sc and Th are by far less mobile.
Results of cluster analysis reveals that sediments are enriched in: i) quartz, feldspars and anhydrite in the most hydrodynamic areas with good connection with the ocean, where tidal currents are stronger and water is salty and well-oxygenated; ii) mud, TOC, phyllosilicates, siderite, pyrite and S in low hydrodynamic areas. In these areas, pyrite and siderite can result from reducing bacterial activity in subsurface sediments. Early diagenetic changes in the sediments would also influence the elements adsorption to clay minerals and their co-precipitation with carbonates (E1). The highest values of REE, in E1, occur in distal locations in relation to the mouths of rivers and streams. The retention of the elements in this phase may occur mainly in the lagoon, depending on the availability of carbonates and clay minerals and their assemblage's composition. Concentrations of REE and related elements adsorbed by organic matter (E2) and by amorphous Mn hydroxide (E3) tend to rise near the rivers mouths and may be related to geochemical processes that take place upstream in the course of the rivers before the entry of sediments into the lagoon. Elemental concentrations retained in the structure of mineral phases (R), also tend to reach high values near the rivers mouths but in low hydrodynamic areas. There is some fractionation between Th and the light REE which is more evident in the Murtosa channel that is fed mainly by the Antuã river.
Virgínia A. Martins, João A. Dias, Cristina Bernardes, Belén Rubio, Ana Bernabeu, Daniel Rey, António M. Soares, Frederico Sobrinho, Lázaro M. Laut, Fabrizio Frontalini, Denise Terroso, Paulo Miranda, Sandra Fernández-Fernández, Maria Antonieta Rodrigues, Rubens Figueira, Sílvia Sousa, Paula Amaral, Michel Mahiques, Fernando Rocha
Martins, V. A., Dias, J. A., Bernardes, C., Rubio, B., Bernabeu, A., , Rey, D., Soares, A.M., Sobrinho, F., Laut, L.M., Frontalini, F., Terroso, D., Miranda, P., Fernández-Fernández. S., Rodrigues, M.A., Figueira, R., Sousa, S.M., Amaral, P. Mahiques, M. and Rocha, F., 2013. The ITRAX core scanner, an useful tool to distinguish anthropic vs climatic influences in lagoon of Aveiro (N Portugal).
The main goal of this work is to distinguish anthropic and climatic influences in sediments from the lagoon of Aveiro (Portugal). This study is based on a core (240-cm long) collected in Murtosa Channel. Optical and X-radiographic images and high-resolution elemental profiles were acquired with ITRAX micro-X-ray fluorescence (XRF) core scanner. Samples collected at each ≈3 cm along the core were analysed for grain size and total organic carbon. Furthermore, the fine fraction of selected layers was subjected to geochemical analysis by ICP-MS, after total acid digestion of the sediments, and mineralogical analysis, by XRD techniques. A radiocarbon age was determined by AMS, using molluscs shells collected at a depth of 90 cm.
Sediments along the core are composed by fine and medium sand, with several mud layers. Sediments composing the first 100-cm may have been deposited after 1950, as it is indicated by the radiocarbon data, the increasing trend of Zn/Al, Pb/Al and Cu/Al and total concentrations of Zn, Pb, Cu, V, Cr, As and Ni in this interval that therefore might be linked with industrial activities of Chemical Complex of Estarreja. The progressive increase of Si/Al, Cl/Al, Rb/Al, K/Al and Br/Al and reduced Al concentrations, from the base to the top of this core, are interpreted as being related to higher marine influence and greater differences in tidal currents with longer exposition to air of the sediments with the consequent formation of brines favouring minerals precipitation in the area (e.g. anhydrite). These results seem to be a consequence of several works developed over time like: i) dredging to improve the navigation access to the harbour, located in the external sector of the lagoon; ii) the control of the course of some rivers influencing the supply of sediments. The tendency of sea level rise may have also emphasized the gradual increase of marine influence in this area. Fine-grained sections, related to an increase in Al, phyllosilicates, organic matter, pyrite and siderite contents would be attributed to phases of greater supply of fine-sediments during heavy rainfall events by the nearby Antuã river and other streams during negative phases of North Atlantic Oscillation. Higher deposition of organic matter enhanced diagenetic changes with pyrite and siderite formation. In the bottom of the core another record of pollution was unveiled to mining activities at the beginning of 20th century.
Mayén, N., Fernández, P. and del Campo, J.M., Almazán J.L., 2013. Small Projects can make big changes in our coast. El Salvador Central America.
Under a General objective to design an optimal and integrated use of the resources by reusing and recycling them to improve the quality life for people with low economic power who lives in the coastal area of El Salvador, we have arrived also to different Specific objectives: to create a simple water collection system, to reuse wastewater, to get the most out of the heat generated by de designing of a green stove, to use plastic bottles as a garbage containers and use them as green bricks, to get energy independence for people who lives in the coastal area of El Salvador, to design a rain water injection system, as a contribution to small river basin and to maintain a friendly and clean environmental coastal areas.
The experiments, made in a coastal house in San Salvador, have got a reduction of electricity consumption by 54.75KWH equivalent of 57% compared with periods before the experiment. Considering that in El Salvador there are 957,480 families with a consumption around 100KWH per month, and if the measures made in the house model are applied in all these houses with at least 80%; it could be saved 503,251488 KWH in a year, in addition 357,308 tons of CO2 will be not send to the atmosphere and the families will save in total USD$149,572,633.
Developing the measures proposed in the scope of this document, with small project will make a big change in each family of the coastal area of El Salvador.
Meireles, A.J. A, Gorayeb, A, Silva, D.R.F, Lima, G.S, 2013. Socio-environmental impacts of wind farms on the traditional communities of the western coast of Ceará, in the Brazilian Northeast
The global expansion of wind power has resulted from the development of scientific research that aims to establish an energy network which minimizes the emission of pollutants derived from the combustion of fossil fuels. Ceará, in the Brazilian Northeast, has a considerable potential for the generation of environment-friendly power, due to the occurrence of strong winds on many parts of the coast and at higher elevations. Given this, the present study aimed to evaluate the socio-environmental damage caused by the installation of a wind farm on the coastal plain of the municipality of Camocim, on the western coast of the state, and to identify the consequences for the coastal environment and the traditional community of Xavier, which survives primarily on fishing, agriculture, and the extraction of natural resources. The study was based on the recognition and definition of the environmental components of the local landscapes, and the mapping of the community's territory, based on the social cartography approach. The study area is characterized by mangrove ecosystems, dune fields, interdunal lakes, fluvial-lacustrine coastal plains, and a sandy beach. The integration of these different environments underpins the traditional lifestyle of the local community, which is based primarily on the exploitation of natural resources. Given this, the community of Xavier, which is made up of 20 families, was affected directly by the installation and subsequent operation of the local wind farm (one of the largest in the Brazilian Northeast, with 50 wind turbines generating a maximum output of 104.4 MW, and approximately 135 km of transmission lines) through (1) the gratuitous occupation of a significant portion of the community's territory, (2) deforestation of fixed dunes, (3) the suppression of dunes by bulldozing, (4) burying of interdunal lakes, (5) disturbance of the margins of fluvial-lacustrine systems, (6) compaction and impermeabilization of the soil, and (7) artificial retention of mobile dunes. These findings indicate that the licensing of wind farms in the state ignores a set of socio-environmental principles. The results of this analysis indicate the need for a regional blueprint for the development of effective socio-environmental policies for the sustainable exploitation of the coastline of the Brazilian Northeast, and in particular for the definition of the sectors most appropriate for the installation of wind farms, such as the coastal plains, which have been classified as the alternative sites with the best potential, as long as effective licensing measures are implemented.
Melo, K.R., Tagliaro, C.H. and, Beasley, C.R., 2013.Seasonal changes in the subtidal benthic macrofauna of a mangrove coast
Mangrove coasts in northern Brazil are subject to seasonal discharges of freshwater input from rivers and terrestrial runoff. However, little is known about the effects of freshwater discharge on the subtidal benthos in the region. Thus, three sites, each representing a different level of seasonal discharge, Canela island (low), Ajuruteua beach (medium), and the Caeté Bay (high) were sampled in the dry (October) and wet (April/May) seasons of 2007 and 2008, respectively. Sampling was carried out using a Petersen grab and a bottom dredge (total n=74). Additional replicas (n=12) were obtained by grab for sediment analyses. Salinity and turbidity of the bottom waters, and percentage of silt/clay in the sediment were also measured. Benthic macrofauna and environmental data were analyzed using uni- and multivariate techniques. A total of 661 individuals were distributed among 47 taxa of which polychaetes and crustaceans dominated at all three sites. No significant differences in macrofaunal abundance were found among sites and dates. At all sites, in the wet season, the number of taxa was low and dominance was high, especially in the Caeté Bay. The polychaete Nephtys fluviatilis only occurred in the Caeté Bay in the wet season, and yet was the dominant taxon (22.7% of total abundance). The Ajuruteua beach and Canela island samples were composed of typically marine taxa. The polychaete Armandia sp., the gastropod Olivella minuta, mysiid and phoxocephalid crustaceans and the echinoderm family Mellitidae were most abundant in the dry season at Canela island. Salinity was the most important environmental factor associated with high numbers of taxa in the dry season. Silt and turbidity were associated with low numbers of taxa in the wet season. In conclusion, the subtidal benthic macrofauna at Canela island, Ajuruteua beach and the Caeté Bay is mainly composed of polychaetes and crustaceans. The higher freshwater discharge in the wet season, resulting in lower salinity, higher percentage silt and greater turbidity, is associated with lower abundance, fewer taxa and a different faunal composition at Canela and Ajuruteua, and strong dominance of an oligohaline polychaete in the Caeté Bay
Mirvakili, H.S., Zaker, N.H., Imani, F., 2013. Evaluation of Oil Pollution and Origin in Surface Coastal Sediments of Kharg Island in the Persian Gulf
Kharg Island in the Persian Gulf is the major oil export terminal of Iran. More than 90% of the Iranian crude oil is exported through the sea oil terminals in this Island. The marine environment of the Kharg Island has been exposed to oil pollution, for several decades, from extensive oil extraction, transportation and refinement. The accidents of oil tankers and the discharges of oily wastewater from crude oil tanks, oil refineries and petrochemical industries are the major sources of the discharge of oil into the coastal area of the Island. The gas flaring emission is another source of marine oil pollution in the Island. The studies on the marine oil pollution in the Kharg Island are very limited.
In this paper the oil pollution of the shallow coastal waters adjacent to the coastline of the Kharg Island is discussed using the analysis of the concentration of hydrocarbons in the sediment samples. Eleven sediment samples were collected around the Island in 2012. The results showed a wide range of TPH concentrations with up to 5624 μg/g in highly polluted samples from the coastal areas near the oil terminals to only a few μg/g in non-polluted areas in the northern part of the Island. PAHs concentrations in the samples were low and ranged between 9.7 and 46.7 μg/g indicating that the coastline sediments were not contaminated with these compounds. The use of several indexes indicated that the hydrocarbons in the polluted sediments were mainly from crude oil.
Péron, C. , Chevallier, D., Martin G., Chatelet A., Anthony, E.J., Le Maho Y., Gardel, A., 2013. Beach morphological changes in response to marine turtles nesting: a preliminary study of Awala-Yalimapo beach, French Guiana (South America)
Each year from February through July, Chelonia mydas (green turtles) and Dermochelys coriacea (leatherback turtles) come to nest on Awala-Yalimapo beach. During the nesting season, the presence of gravid turtles may directly affect the general morphology of the beach by provoking sand remobilization during firstly the conception of their nest and then during the nest disguising. Digital elevation models were realized to qualify and quantify the topographic modification conducted by the macro-bioturbation effect of marine turtles. Green turtles and leatherback turtles do not provoke the same perturbation on the beach. C. mydas affect the upper part of the beach by constructing their nest. Whereas D.coriacea provoke more important impact on the lower upper-beach when they come to lay. During the covering activity leatherback tend to disturb the morphology of the beach around their nests. Morphological changes on the beach during the nesting season draw attention to the potential effect of animal on their terrestrial habitat.
Ra, K., Kim, E.-S., Kim, K.-T., Kim, J.-K., Lee, J.-M., and Choi, J.-Y., 2013. Assessment of heavy metal contamination and its ecological risk in the surface sediments along the coast of Korea.
We studied the spatial distribution of heavy metal contamination and its ecological risk assessment in sediments from the Korean coast. Surface sediments collected from 12 coastal zones of Korea (total 200 sediment samples) along the west, south and east coast of Korea have been analyzed for heavy metals including Cr, Co, Ni, Cu, Zn, As, Cd, Pb and Hg using ICP-MS. Mean concentrations were 58.3 mg/kg for Cr, 10.2 mg/kg for Co, 24.3 mg/kg for Ni, 36.5 mg/kg for Cu, 122 mg/kg for Zn, 9.1 mg/kg for As, 0.25 mg/kg for Cd, 35.0 mg/kg for Pb and 0.046 mg/kg for Hg, respectively. Sediments sampled from heavily industrialized areas such as Shihwa, Masan, Gwangyang and Ulsan were highly contaminated with Cu, Zn, Cd and Hg. Significantly positive correlation among metals were observed (p<0.01). This suggests that sources of metal contamination were mainly attributed to anthropogenic inputs from surrounding environment, especially national industrial complexes that consist of iron, steel, machinery, electronics and petrochemical. The results of metal assessment indices indicated that the Korean coast sediments were moderately contaminated with Cu, Zn, As, Cd, Pb and Hg. The mean of metal enrichment levels decreased following the order of Cu>Hg>Cd>Zn>As>Pb>Co>Cr>Ni. Based on the comparison with sediment quality guidelines (SQGs), Cu, As and Zn levels at more than 40% of sediment samples exceeding TEL values are likely to result in potential adverse effects on sediment-dwelling organisms.
Richards, R., Hughes, L., Gee, D. and Tomlinson, R., 2013. Using generalized additive models for water quality assessments: A case study example from Australia
Water quality management is an ongoing challenge for coastal managers. They are faced with disentangling the multiple determinants involved when assessing the utility of management interventions, understanding the processes behind historical trends and progress towards future water quality goals. Nonparametric statistical methods such as locally weighted scatterplot smoothing are often used in water quality assessments for this purpose while generalized additive models (GAMs) have been applied sparingly. Conversely, the extensive use of GAMs for air quality studies because of their reported ability to account for nonlinear confounding effects of seasonality, covariate trends and weather variables indicates that this is a statistical method that is well–suited to water quality studies. In this paper, we present a case–study application of GAMs in demonstrating the potential for this methodology to be used for trend analysis of water quality datasets. The case study is based upon an extensive water quality monitoring program that recently took place along the coastal region of the Gold Coast, Queensland, Australia. We use GAMs to uncover the functional relationships between a common water quality indicator (turbidity) and the suite of predictor variables that are expected to influence turbidity. The selection of suitable candidate predictors to trial in the model is based on expert judgement regarding the key determinants of turbidity in the case study area and is partially undertaken to minimise the effects of ‘colinearity' in the predictor variables. Overall, the GAM approach performed well and provided insight into the drivers of turbidity for the case study area.
Rocha, C., Cordeiro, N., Nolasco R., Dubert J., 2013. Numerical modelling of the phytoplankton patterns in an upwelling event off the NW Iberian Margin.
An extreme event in September 2007, presenting a strong upwelling core detaching from the Galician NW coast and extending towards west-northwest from the Cape Finisterre - Cape Ortegal zone, with the formation of several filaments and a consequent strong response in chlorophyll concentration values is analyzed. To do so, a NPZD biogeochemical module coupled to a ROMS_Agrif configuration is used. The model response was satisfactory and an analysis of the event, including its forcing, was made. The particular wind direction and intensity along with the specific coastal orientation of the study area were identified as important characteristics for the development of the event. The analysis of the behavior and evolution of this phytoplankton bloom may give further insight in the relations between atmospheric forcing, the consequent characteristic coastal ocean processes, and their conditioning in phytoplankton distribution and patterns in the study area.
Rosa Filho, J. S. and Aviz, D. Macrobenthic communities of an Amazonian estuary (Guajará Bay, Brazil): temporal and spatial changes.
This study describes the spatial and temporal patterns of changes in the macrobenthic communities of Guajará Bay, an estuary in northern Brazil. Samples were collected at seven sites in the dry (December 2004 and September 2005) and rainy seasons (March and June 2005). On each occasion, four biological samples and one sediment sample were collected at each site using a Petersen grab (0.039 m2). Simultaneously, the pH of the surface water, salinity, electrical conductivity and temperature were measured. Water parameters, except temperature, showed strong seasonal variation. As a general rule, pH, salinity and electrical conductivity were higher in the dry season and increased toward the mouth of the estuary. Sediment characteristics varied little in space or time. Almost 99% of all the specimens collected were annelids. The abundance and diversity of the organisms were significantly higher in the rainy season, when there was a marked increase in the abundance of oligochaetes and insect larvae, whereas polychaetes predominated during the dry season. The results of the ANOSIM indicated significant differences in the composition of the macrofaunal communities between seasons. The groups formed by the CCA reflected the distance from the mouth of the estuary. At the innermost sites, characterized by lower electrical conductivity and rich, organic sandy sediments, oligochaetes predominated, whereas at the sites further downstream, where more saline conditions predominate, polychaetes were found in higher densities. The results indicated that the structure of the macrobenthic communities in this estuarine bay are structured primarily by salinity, and secondarily by seasonal changes in rainfall rates, which affect the characteristics of both the water and sediments.
Sousa, J.A., Cunha, K.N. and Nunes, Z.M.P., 2013. Influence of seasonal factors on the quality of a tidal creek on the Amazon coast of Brazil.
The nutrients produced by mangrove ecosystems play an important role in the fertility of tropical estuaries. The highly indented Pará-Maranhão littoral is part of the Amazon Coast, and is formed by an extensive array of inlets, bays and estuaries. Tidal creeks connect the local mangroves to the adjacent bays and estuaries. The Emboraí Velho creek is located on a local oyster farm, where the monitoring of the water quality is an essential routine. This study investigated the effects of seasonal variation in conditions on the quality of the water of this tidal creek. The samples were collected each month between April, 2009, and July, 2011, during the spring tide. The temperature, salinity, pH, turbidity, conductivity, and dissolved oxygen concentration of the water were analyzed in situ using a multiparameter probe. Water samples were also collected for nutrients and chlorophyll-a analysis in the laboratory. Salinity and conductivity varied significantly (p < 0.05) among the different periods. Mean salinity ranged from 21±6.90, in the rainy season, to 35±2.66 in the dry, with mean conductivity following the same trend, varying from 33±10.14 mS.cm−1 in the rainy season to 54±3.67 mS.cm−1 in the dry. During the flood tide, the mean chlorophyll-a concentration was higher in the rainy season (12.75±5.13 mg.m−3) in comparison with the dry (9.85±1.86mg.m−3). None of the other variables varied significantly between the periods analyzed. These results reinforce the need for the regular monitoring of water quality in order to determine the periods when environmental conditions are appropriate for oyster farming.
Tay, H.W., Bryan, K.R. and Pilditch, C.A., 2013. Dissolved inorganic concentrations in an estuarine tidal flat
Waikareao Estuary is a shallow tidally dominated estuary located in Tauranga Harbour, New Zealand. The primary aim of this study was to determine the seasonal variations in nitrate and ammonium concentration in sediment pore-waters on a tidal flat margin in the Waikareao Estuary. Vertical profiles of sediment pore-water were sampled 5, 10, 25, 50 and 75-cm depths to provide snapshots of nutrient concentration at different times of the year. Pore-water recycling processes were an important source of dissolved inorganic nitrogen (DIN) to the estuary during low tide with greatest concentrations observed in mid-winter and summer. Pore-water profiles showed ammonium as the dominant form of DIN in the wells. Nitrate concentration was higher in surface sediment and ammonium dominated the mid-depth regions (25–50 cm). The vertical stratification of the DIN in the wells suggested oxidation at the surface produced higher nitrate concentrations while at deeper depths, ammonification and dissimilatory nitrate reduction to ammonium produced higher ammonium concentrations. Long-term monitoring by the Regional Council of Kopurereroa Stream which discharges into Waikareao Estuary, showed higher nitrate concentrations than the tidal flat wells and other monitored sites. This further highlights that the primary source of nitrate into estuaries is through freshwater discharge and ammonium is dominated by sediment recycling processes.
Açanal, L., Loukogeorgaki, E., Yagci, O., Kirca, V.S.O. and Akgül, A., 2013. Performance of an inclined thin plate in wave attenuation
In practice, in some cases, tandemly applied pile-mounted horizontal or inclined thin plates emerge as functional coastal structures in terms of diminishing wave height in front of Rubble Mound Breakwaters (RMBs) and consequently, reduce the required armor unit size and RMB's overall weight. In this study, the hydrodynamic performance of an Inclined Thin Plate (ITP) under regular waves is experimentally investigated. The objective of the laboratory experiments is the assessment of the ITP's efficiency in terms of wave attenuation. Various inclination angles in combination with different submergence degree of the structure under various wave conditions are examined. Regarding the examined ITP configurations, three different inclination angles are considered, i.e. 5, 10, and 15 deg as well as a horizontal plate on the free surface. For the inclined configurations, ITP was placed in a manner such that 2/3 and 3/4 of its length was submerged. The findings revealed that the transmission coefficients can be reduced down to 0.2–0.3. The findings revealed that a tandemly applied ITP has great functionality in diminishing the wave height at the seaward side of a RMB. In this way, the overall weight of the RMB and the weight of the armor units of the RMB are markedly reduced, which is highly necessary in cases where the foundation stability is poor.
Akgul, M.A., Yilmazer, D., Oguz, E., Kabdasli, M.S., Yagci, O., 2013. The effect of an emergent vegetation (i.e. Phragmistes Australis) on wave attenuation and wave kinematics
Coastal vegetation acts as a natural barrier at many coastal zones, protecting the landside against wave effects and coastal erosion. It is known that coastal vegetation affects wave properties, and studies regarding this topic have been made in a wide variety, mostly focusing on wave attenuation. In this study, laboratory experiments have been conducted in a wave basin to inspect the effect of an emergent vegetation on wave attenuation, wave transformation and wave kinematics. A blank area is present along the reed field, which enables energy transformation during wave propagation. Three different regular waves have been sent to a natural reed field, and wave heights and kinematics have been measured around the structure. The results indicate that crest-parallel energy transmission takes place as the waves propagate along the reed field, which is boosted at the end of the reed, and the transmission becomes faster on waves with higher wave steepness. Measured water particle velocities have been evaluated to obtain the steady-cyclic and fluctuation components, by which, turbulence intensities in front and at the wake of the reed field have been evaluated. The results indicate that turbulence intensity increases at the mid-depth at the wake of the structure, becoming higher with increasing wave steepness. Thus, one may conclude that energy dissipation takes further place after the end of the reed field due to turbulence.
Aristodemo, F., Tomasicchio, G.R. and Veltri, P., 2013. Wave and current forces at a bottom-mounted submarine pipeline.
The present work deals with the analysis of in-line and transverse forces for a bottom-mounted slender pipeline subjected to periodic motions characterized by non-linear Stokes and cnoidal waves, and also with a superimposed positive current. Full-scale laboratory tests were conducted in the large wave flume of CSMI at Padua, Italy, and characterized by a longitudinal vertical wall which was built in the flume to create two separate channels where simultaneous measurements of pressures, velocities and surface elevations were performed. The experimental dataset was defined by 39 tests with periodic waves using a smoother cylinder, 14 tests with periodic waves using a rougher cylinder and 11 tests with periodic waves plus currents, leading to a Keulegan-Carpenter number ranging from 4 to 13. The hydrodynamic coefficients of Morison and transverse force models were deduced from the time records of kinematics and pressures at the cylinder through the evaluation of the performances of time and frequency domain techniques such as the ordinary and the weighted least squares. The comparisons between experimental and calculated non-linear forces in terms of peaks, associated phase shifts and spectral densities show acceptable accuracy as regards the Morison force components and a poor estimation of the vertical forces.
Bakhtyar, R., Razmi, A.M., Barry, D.A., Yeganeh-bakhtiary, A. Kees, C.E., and C.T. Miller, 2013. Two-Phase Flow Modeling of the Influence of Wave Shapes and Bed Slope on Nearshore Hydrodynamics.
An Eulerian two-phase flow model (air-water) was used to simulate nearshore hydrodynamic processes driven by wave motion. The flow field was computed with the Reynolds-Averaged Navier-Stokes equations in conjunction with the Volume-Of-Fluid method and the RNG turbulence-closure scheme. To study the effects of different wave shapes on surf-swash zone hydrodynamics, a set of numerical experiments was carried out. Predictions of three wave theories (Airy, 2nd-order Stokes and 5th-order Stokes) were compared, with a focus on the turbulence and flow fields. Model performance was assessed by comparing numerical results with laboratory experimental observations. Relationships between the water depth, undertow, TKE and wave characteristics are presented. The results indicate that the characteristics of turbulence and flow, for example the position of wave breaking and magnitude of TKE, are affected by different wave types. Numerical simulations showed that only high-order Stokes wave theory predicts the nonlinearity required for predicting hydrodynamic characteristics in agreement with existing understanding of nearshore processes. Numerical simulations were run for different hydrodynamic conditions, but with a focus on different bed slopes. The transformation of incoming waves as they reach shallow water occurs closer to the shoreline for steeper profiles. Consistently, the peaks in TKE and wave set-up are shifted onshore for steeper slopes. The numerical results showed that TKE and undertow velocity are smaller on dissipative beaches than on intermediate beaches.
Chris Brown†, 2013. Monitoring and Maintenance of Plymouth Breakwater
This Breakwater now has four zones of discrete armour: -
the submerged foreshore rock slope
tidal berm – rock partially covered by 100te precast concrete blocks known as Wavebreakers at a coverage of between 40 and 80% deposited from unique catamaran pontoon
an impermeable fitted masonry carapace over the crown of the Breakwater from LWM to LWM
on the lee side, rock from LWM to the seabed
Concerns have long been raised regarding the stability of both roundheads, the foreshore berm and the 100te Wavebreakers on the berm. Although records of placement of materials exist from 1839 to date, these do not allow accurate estimation of movement to be made. Nor do repetitive cross-sectional surveys, as made between 1840 and 1995, allow any more than a gross approximation of volume change to be made, and then only at discrete sections.
Recent developments with GPS, aerial LIDAR and sonar bathymetry have allowed much greater accuracy in offshore surveying than in the past and for the first time an integrated digital baseline survey of the Breakwater was undertaken in 2011, to a sub-aerial accuracy of better than 10cm. Using this, a new basis for monitoring the breakwater is available. The potential for this work to be accompanied by both desk and model studies to determine the limits of stability and the service performance of the Breakwater, so that a final profile can be confirmed and its integrity demonstrated would be greatly enhanced by input from the academic community.
Buccino, M., Del Vita, I., and Calabrese, M., 2013. Predicting wave transmission past Reef BallTM submerged breakwaters
Reef Balls™ are hemispherical shaped artificial units, made of neutral concrete and characterized by a particular surface textures to promote the growth of marine life. They can be arranged in different layouts to form submerged breakwaters, even of significant width. Although structures in Reef Balls have been employed for the protection of a number of top quality sites, no well-established design tool exists for the prediction of wave transmission behind them. In this article a set of equations is provided, based on the so-called “Conceptual Approach” originally developed for ordinary structures. The new expressions proved to fit properly more than 300 experimental data, coming from physical model tests conducted at two different American laboratories: Queen's University Coastal Engineering Research Laboratory (Canada) and the USACE Engineering Research and Development Center Coastal and Hydraulics Laboratory (USA).
Chen, Y. P., Xie, D. M., Zhang, C. K, Qian, X. S., 2013. Estimation of long-term wave statistics in the East China Sea.
This study used a state-of-the-art approach to estimate the long-term wave statistics in the East China Sea. The wave climate in the past 60 years (1950–2009) was simulated by a third generation wave model driven by the NCEP/NCAR reanalysis wind data. Based on the statistical analysis of the numerical results, the mean wave fields and the extreme wave fields with 100-year and 50-year return period on the whole computational domain were obtained. The spatial variations of the wave fields show that the statistical waves decrease from south to north and from sea to coast in general, which can be associated with the local topography of the East China Sea. The seasonal variations show that the mean waves in the winter and autumn are slightly larger than those in the spring and summer, while the extreme waves in the summer are much larger than those in the other seasons, which is mainly due to the seasonal variation of monsoonal winds and the occurrence of typhoon events in the summer. The outputs of this paper are helpful to understand the distribution of mean and extreme waves in the East China Sea, and also useful to calculate the design waves in the coastal area if nearshore wave model like the SWAN model is introduced.
Choi, J.-Y., Park, J.-Y., Cho, K.-H., Hyun, S.-K., Yoo, J., Lee, D.-Y. and Jun, K.-C., 2013 Field observation and modeling of wave set-up on a macrotidal beach: the Malipo Experiment.
Korea Research Ocean & Development Institute (KORDI: now renamed the Korea Institute of Ocean Science & Technology, KIOST) conducted a field observation experiment (the Malipo Experiment) using a variety of wave gages and current meters simultaneously at the Malipo Beach, South Korea, from December 2009 to March 2010 in order to understand the coastal processes in a macrotidal environment. The Malipo Beach has a typical macrotidal beach environment characterized by a very gentle beach slope of 1/50 and strong tidal currents corresponding to the extreme tidal range of 7 m. As a part of this program, we observed the intertidal-zone wave set-up using a wave-rider buoy moored at 20 m water depth and seven pressure-type wave gages perpendicularly aligned to the shore at the intertidal zone for 17 days beginning from December 17th, 2009 in order to understand wave breaking and set-up characteristics in the macrotidal environment. Based on the observation data analysis, the relationship between the wave set-up and wave height at offshore (Hs,0) is η = 0.11Hs,0 showing that influence of alongshore tidal currents on the wave set-up was negligible. It was analyzed that, however, wave set-up might be influenced by shore-normal currents. The wave set-up at the study site was smaller than previous researches. It might result from its low breaking index and the wave characteristics of short wave period and wide-spreading directional spectra at the study site. Results of model simulation by combining a wave model with a circulation model showed that simulated wave set-up heights were generally lower than the measurements.
Chun, I., Min, Y., Ha, D. and Park, K., 2013. A General Purpose Numerical Tool for Determining Wave Control Capability of Perforated Coastal Structures
Perforated breakwaters or seawalls have been installed as structures to maintain water surface tranquility inside or outside harbors by suppressing wave reflection or overtopping. In addition, they can also reduce the impact of wave-breaking forces acting on the structure, ultimately increasing its structural stability. Recently, they have been often employed as transmissive structures that facilitate sea water exchange between the inside and outside harbors. Here, analytical and experimental studies were performed to establish a numerical tool for predicting the wave control characteristics of general perforated coastal structures under regular wave conditions. The numerical analysis, which is based on a boundary element method, was established to calculate wave reflection and transmission coefficients as well as wave pressures and forces acting on various perforated wall structures. This analysis could also accommodate any length of curtain and sill above and below the perforated walls, depth variations among wave chambers, porous materials filling the wave chambers, etc. The friction factor on the perforated walls was revealed in the analysis by an experimental formula extracted from a separate hydraulic experiment. In addition, the nonlinear frictional loss through the perforated wall was determined through an iterative calculation procedure. Hydraulic experiments were also carried out for several types of perforated wall structures, and their results were in good agreement with the numerical values. In addition, the numerical tool was also applied to experimental conditions identical to those of existing studies on perforated wall structures. These results also showed good agreement between experimental and numerical values. Finally, a user-friendly computer program was developed to facilitate the design practice of perforated structures.
Denissenko, P., Didenkulova, I., Rodin, A., Listak, M. and Pelinovsky, E., 2013. Experimental statistics of long wave runup on a plane beach.
A series of experiments at the 300 m length and 3.5 m depth Large Wave Flume (GWK), Hannover, Germany is conducted to study the statistics of long wave runup on a plane beach. Major goal of this experimental study is to test the applicability of the theoretical model based on rigorous solutions of the nonlinear shallow-water equations for waves on a sloping beach. According to the theory, the extreme values of the runup displacement and velocity of the moving shoreline, and consequently statistical distributions of extreme runup characteristics can be found from the associated linear theory. In particular, if an incident wave field is represented by a narrow-band Gaussian process, extreme runup characteristics can be described by the Rayleigh distribution even for strongly nonlinear waves. It is shown that the distribution function of the extreme runup characteristics can be approximated by the Rayleigh curve in the wide range of wave amplitudes and spectra even if an incident wave field is represented by a non-Gaussian process.
Díaz-Sánchez, R., López-Gutiérrez, J.S., Lechuga, A., Negro, V., Esteban, M.D., 2013. Direct estimation wave setup as a medium level in swash.
The extreme runup is a key parameter for a shore risk analysis in which the accurate and quantitative estimation of the upper limit reached by waves is essential. Runup can be better approximated by splitting the setup and swash semi-amplitude contributions. In an experimental study recording setup becomes difficult due to infragravity motions within the surf zone, hence, it would be desirable to measure the setup with available methodologies and devices. In this research, an analysis is made of evaluated the convenience of direct estimation setup as the medium level in the swash zone for experimental runup analysis through a physical model. A physical mobile bed model was setup in a wave flume at the Laboratory for Maritime Experimentation of CEDEX. The wave flume is 36 metres long, 6.5 metres wide and 1.3 metres high. The physical model was designed to cover a reasonable range of parameters, three different slopes (1/50, 1/30 and 1/20), two sand grain sizes (D50 = 0.12 mm and 0.70 mm) and a range for the Iribarren number in deep water (ξ0) from 0.1 to 0.6. Best formulations were chosen for estimating a theoretical setup in the physical model application. Once theoretical setup had been obtained, a comparison was made with an estimation of the setup directly as a medium level of the oscillation in swash usually considered in extreme runup analyses. A good correlation was noted between both theoretical and time-averaging setup and a relation is proposed. Extreme runup is analysed through the sum of setup and semi-amplitude of swash. An equation is proposed that could be applied in strong foreshore slope-dependent reflective beaches.
Didenkulova, I., Denissenko, P., Rodin, A. and Pelinovsky, E., 2013. Effect of asymmetry of incident wave on the maximum runup height.
Shoaling and runup of long waves on a beach form a classical task for coastal oceanography and engineering. Though many empirical and theoretical formulae have been developed in this field, most of them are targeted to typical waves and situations, while the greatest hazard is caused by extreme events, such as, for example, extreme storms and catastrophic tsunamis. From this point of view it was shown theoretically that one of the most important parameters which influence the wave runup height is the steepness of the incident wave front and the asymmetry of the incident wave. It helped to provide a simple explanation to the extreme runup observed during the catastrophic 2004 Indonesian tsunami event. However, the theoretical results were obtained under many assumptions (ideal fluid, no wave breaking, no bottom friction) and have not been validated. Here we present an experimental study performed in the Large Wave Flume (GWK), Hannover, Germany, which is focused on the influence of the asymmetry caused by the non-linear deformation of incident waves on their runup on a plane beach. The series of experiments are aimed to validate the theoretical formulae for runup height of asymmetric waves. Obtained results are in a good agreement with theoretical predictions and corresponding formulae are recommended to be considered in wave forecasts.
Didenkulova, I., Sheremet, A., Torsvik, T. and Soomere, T., 2013. Characteristic properties of different vessel wake signals.
The potential threat in terms of environmental protection and safe navigation posed by wake waves from high-speed ferries and fast conventional ships is well documented. Vessels that travel in the near-critical regime (depth Froude number ~1) at some sections along their ship tracks can generate packets of large, solitonic, very long and long crested waves. However, it is difficult to determine a general characterization of such wakes at the coast, due to the transient and nonlinear nature of this phenomenon, and the fact that wake impact is influenced by the local bathymetry and coastline configuration. This paper investigates the potential benefits of wake analysis by means of a time-frequency technique (windowed Fourier transform), which is a standard signal analysis method that has only recently been applied for wake analysis. Analysis of ship wakes have been performed based on instrumental data of sea surface elevation recorded at different sites in Tallinn Bay, the Baltic Sea, which is characterized by very intense ship traffic and provides a rich collection of vessel-wake signals. Results show that the wake signals are easily identified in spectrograms. The method is particularly useful for identification of low frequency signals that may easily be masked by high frequency noise in the wave record. Furthermore, the spectrogram provides information that makes it possible to associate wake events with individual ships at a given location. This approach also opens a new direction for the statistical description of wakes, applicable to the characterization of the “wake climate” for sites with intense vessel traffic.
Feng, X., Shaw, A.G.P. and Zhang, W., 2013. Study on reverse calculation for unidirectional waves from shallow water
In the coastal region, some wave measurements are usually deployed in shallow water. However, the knowledge of deep-water waves is more required in some cases. Targeting the east coast of Taiwan with a steep slope, we experimentally detect the capability of the linear spectrum theory in reversely estimating unidirectional deep-water waves from the shallow-water waves. Tank experiments of irregular waves show that the nonlinearity of wave-wave interactions significantly contributes to the total energy transfer. The energy of incident waves around peak frequency is transferred to lower and higher frequency domains. Even though waves are travelling through a short distance under a steep slope, the nonlinear wave-wave interactions cannot be neglected. In the application of the linear spectrum theory, the reversely calculated deep-water spectrum is found to be overestimated in frequency over 2Hz and in total energy of spectrum, but underestimated around peak frequency. There is evidence to show that the ratio of H1/3/Hs is correlated with the spectral bandwidth and Kurtosis.
Fernández Lázaro, A., Gutiérrez Serret R.M., Negro, V. and López-Gutiérrez, J.S., 2012. Use of a scrapped ship as a floating breakwater for shore protection.
The purpose of this research is to assess the effectiveness of a ship used as a detached floating breakwater for coastal protection and forming salients of sand or tombolos. Floating breakwaters have been extensively used as port or coastal protection structures and display advantages in terms of construction and ecology, amongst others. However, the greatest problem these structures present is the limited range of wave heights and periods for which they are really effective. Furthermore, ships may be considered as floating structures which, used as breakwaters, would keep the advantages of floating breakwaters and would increase their range of applicability. The possibility of using ships at the conclusion of their useful life for this purpose would also involve greater economic and environmental advantages. Tests were carried out to assess the ship's effectiveness as a detached floating breakwater using a scaled down physical model to determine the vessel's transmission coefficient (Kt) as to regular waves with significant periods of 5 sec to 12 sec and significant wave heights of 1.5 m to 4 m at depths from 20 m to 35 m. The ship proves effective for waves up to 4 m significant height and significant periods up to 9 sec. Hanson and Kraus and Pilarzyk's analytical models, which take transmission coefficients into account, were used to analyse the shore's response to the breakwater protection. The results obtained show that salients form for waves with periods between 6 sec and 9 sec. It is also concluded that the depths tested are far different from the more usual shallow water involved in constructing detached breakwaters and the shore's response is therefore scarce.
Giudici, A., Soomere, T., 2013. Identification of areas of frequent patch formation from velocity fields.
We explore the ability of the formation of patches of substances floating on the sea surface owing to intrinsic features of ocean circulation associated with persistent flow convergence in areas characterised with strong vertical velocities (e.g. hosting downwelling). Their impact on the field of surface floaters can be quantified using so-called flow compressibility of a two-dimensional velocity field. Large values of this measure for idealized, delta-correlated-in-time flows are directly related to the tendency of floating tracers to gather into patches. We employ a modification of this measure, so called finite-time-compressibility to describe the real marine flows in a more consistent way, accounting for the match of areas with high convergence with the Lagrangian transport of the resulting patches. Analysis of this measure for the Gulf of Finland, the Baltic Sea, using surface velocity fields from the OAAS model with a resolution of 1 nm shows that domains where systematic development of patchiness is very likely occur either along straight sections of the coastlines that usually host downwelling. Surprisingly, high values of finite-time compressibility frequently occur throughout the year in two offshore locations and in the windy season near the centre of the widest part of the gulf.
Hadadpour, S., Moshfeghi, H., Jabbari, E. and Kamranzad, B., 2013. Wave hindcasting in Anzali, Caspian Sea: a hybrid approach.
Wave characteristics are necessary for many coastal operations and marine structures design. Different methods such as empirical methods, numerical models and soft computing have been developed for this purpose. In this study, one of the well-known numerical models, SWAN model, has been used for the prediction of wave parameters in Anzali, Caspian Sea. Wind field is one of the most important factors in the wave modeling. In this study, QuikSCAT wind field was investigated for wave hindcasting in Anzali using SWAN model. For this purpose, the gaps in the QuikSCAT measurements data were filled using spatial interpolations. Furthermore, the Anzali buoy recorded data were used to calibrate and validate the model. In order to select the appropriate intervals of calibration and verification, the statistical similarities between corresponding data in both periods were considered. Hence, the buoy was located in deep water the whitecapping dissipation coefficient was more influential than friction and breaking effects on the results. Finally, the numerically modeled wave characteristics were improved using linear transfer function and artificial neural network (ANN). The results indicated that the wave characteristics modification using ANN yields more accurate results in comparison with linear transfer function.
Jung, J.-S. and Cho, Y.-S., 2013. A 3D Hydrodynamic Model for Determination of Maximum Food Level inside Saemangeum Embankment
In this study, the variation of flood water level inside the Saemangeum Embankment is studied. In particular, the maximum flood level inside the Embankment is investigated for design of the land reclamation level. Water level inside the Embankment may be affected by flooding from connected rivers, tides and discharges through gates. The tidal range outside Embankment is about 6.0~7.5m. The water level is numerically simulated by using a commercial hydrodynamic model: Delft3D-Flow. By analyzing measured tidal data measured over 31 years (1981–2011), the smallest tidal difference is selected for simulations. The maximum flood level inside Embankment generally increases as the tidal difference decreases because the sea level outside Embankment is relatively high during the ebb tide.
Kamranzad, B., Etemad-Shahidi, A., Chegini, V. and Hadadpour, S., 2013. Assessment of CGCM 3.1 wind field in the Persian Gulf
Increasing of the greenhouse gases emission causes the climate changes. Therefore, usage of the marine renewable energy resources such as wind and wave energies has been increased during the last decades. Climate variability can change the wind and consequently wave patterns and the available energy amounts. Therefore, assessment of the potential effect of climate change on the wind regime is important. In this paper, wind characteristics obtained from a global climate model (CGCM 3.1) is used for assessing the effects of climate change on the wind regime in the Persian Gulf. CGCM 3.1 results were compared quantitatively with those of ECMWF in the Persian Gulf and the results showed that in comparison to ECMWF, CGCM 3.1 wind speeds are mostly underestimated for both average and maximum values. Dominant wind directions represented by two wind fields are nearly similar except for a point located in Strait of Hormuz. Variations of the annual wind speed in this area were also evaluated until 2100 and time series of annual averages of the wind speeds and statistical analysis indicate a decreasing trend in all points in the domain. Variation of wind speed frequency based on CGCM 3.1 winds was also assessed for different intervals and the results showed that the variations of wind speed frequencies are marginal. Although there is a insignificant reduction in the average wind speed, this can lead to large variations in the wind and wave energies and also extreme values of wave characteristics.
Kang, S.K., Jung, K.T., J.J. Park, Kim, E.J., and So, J.K., 2013. Tidal Regime Change of the Large Scale of Reclamation in the West Coast of the Korean Peninsula in the Yellow and East China Sea.
A depth-averaged two-dimensional numerical model has been established in order to investigate tidal regime change by the large scale of reclamation in the west coast of Korean Peninsula. The fetched variable-grid system was used to discretize the complicated coastal region efficiently. Maximum six month integration of the model was carried to investigate the tidal change over 10 tidal components prescribed along the open boundaries consisting of the Ryuku Islands, Korea Strait, and Tiwan Strait. The tidal regime change appears widely in the whole Yellow Sea and its effect reaches to the shelf break region in the East China Sea. The Kelvin-wave type distribution of tidal amplitude along the west coast of KP is distorted and the propagation speeds of semi-diurnal and diurnal tidal waves increase around the reclamation and neighboring regions. The change of the propagation speed after reclamation seems to be due to weaker lateral friction by simplification of the land boundary. The tidal amplitudes decrease within several tens of km just around the reclamation area, while the amplitudes outside the region increase slightly. Such decreasing or increasing patterns appear alternatively. This implies that the change of tidal regime propagates toward the remote region far away from the reclamation site. Therefore, prescription of tidal components as open boundary condition should be carefully determined after considering any possible tidal regime change near the boundaries by reclamation of an inner model domain. The model result also confirms that friction at the lateral boundary affects the propagation of tidal waves as much as the bottom-friction effect.
Kazeminezhad, M.H., 2013. Numerical simulation of oscillatory flow around submarine pipelines
Submarine pipelines, which often installed over seabed without any protection, are widely used to transport products from one location to another. In shallow water regions, the pipelines are affected severely by the wave-induced oscillatory motion. In this study a numerical model is presented to simulate the flow pattern around pipeline exposed to the oscillatory flow. The flow hydrodynamics is described via the solution of the Reynolds-Averaged-Navier-Stokes equations with a k-ϵ turbulence closure model. The numerical model is employed to describe the flow pattern, vortex shedding, gap flow prevailed below the pipe and hydrodynamic forces in oscillatory flow condition. Then, the flow velocity in the gap beneath pipe is discussed for different gap to diameter ratios in both unidirectional and oscillatory flow conditions. Results indicated that the k-ϵ turbulence closure model is capable of simulating the vortex shedding behind the pipe in oscillatory flow condition. It is also indicated that for the oscillatory flow case (KC=7, Re=9500), the maximum velocity of the gap flow increases with decreasing the gap between pipe and bed surfaces. By contrast, in the steady current case (Re=9500), the maximum velocity of the gap flow slightly decreases with decreasing the gap. In oscillatory flow conditions, a phase-lag between the gap flow and free-stream flow was found, especially for the small gap ratios. The relative maximum flow velocity between pipe and bed surfaces (umax gap/um) decreases as the Keulegan-Carpenter number increases. According to the obtained results, the maximum velocity of the gap flow in oscillatory flow conditions is higher than that of the steady currents.
Kim, D.C., Kim, K.O., Pelinovsky, E., Didenkulova, I. and Choi, B.H., 2013. Three-dimensional tsunami runup simulation for the port of Koborinai on the Sanriku coast of Japan.
The huge tsunami generated by the earthquake that occurred off the Pacific coast of Japan at 14:46 JST (05:46 UTC) on Friday, 11 March 2011 produced a maximum runup of 40 m on the east coast of Japan. The earthquake triggered extremely destructive tsunami waves up to 37.9 m in height that struck Japan minutes after the quake. Koborinai is a tiny fishery port located north of Miyako City in the Iwate Prefecture. A survey team from the University of Tokyo Earthquake Research Institute (ERI) found high water marks and other evidence of a gigantic wave at the port of Koborinai. The port is on low land sandwiched between two mountains. A joint survey team from ERI-Sungkyunkwan University (SKKU) and Korea Ocean Research & Development Institute (KORDI) visited again and surveyed the site in detail. The 3D Princeton Ocean Model was applied to describe the propagation and runup of the tsunami on the Japanese coast. The numerical simulation results obtained were in satisfactory agreement with observations made in the general area, except those made in many v-shaped valleys along the northern Iwate coast. The extremely high runup of tsunami waves at the port at Koborinai were successfully reproduced by numerical simulation through stepwise refinement of the spatial scale using multi-nesting and consideration of the vertical acceleration of flow along steep slopes using a CFD model to solve the Reynolds-averaged Navier–Stokes (RANS) equations. The velocity field was also computed, and the simulation results show that the water flow that climbed the coast possessed a strong vertical velocity component.
Kim, D.C., Kim, K.O., Choi, B.H., Kim K.H. and Pelinovsky, E., 2013. Three-dimensional runup simulation of the 2004 Indian Ocean tsunami at the Lhok Nga twin peaks.
A post-tsunami runup survey for the 2004 Sumatra–Andaman earthquake showed that the highest runup which was recorded at Lhok Nga (West Banda Aceh, Sumatra). A reported maximum tsunami height of 35 m and maximum runup height of up to 51 m occurred near the Lhok Nga Twin Peaks (Labuhan and Ritieng). A numerical simulation was performed to reproduce tsunami characteristics in this area. The tsunami source was computed using fault parameters proposed by Tanioka et al. Tsunami wave propagation from the source to the coast was studied with 3D shallow-water equations. The coastal runup behavior of the tsunami at the Lhok Nga Twin Peaks was studied within a framework of fully nonlinear dispersive Reynolds-averaged Navier–Stokes equations using the FLOW3D code. This approach made it possible to reproduce the extreme characteristics of the tsunami in this coastal area, including observed overflow through a saddleback between the twin peaks. The numerical simulation results compare well with data from field surveys.
Kim, K.O., Jung, K.T. and Choi, B.H., 2013. Propagation of a tsunami wave generated by an earthquake in the Nankai Trough onto the South Korean coast.
The earthquake of magnitude 9.0 that occurred in March 2011 and the ensuing crisis at the Fukushima Daiichi nuclear power plant prompted sweeping reviews of Japan's disaster preparedness and criticism over apparent failures to take into account potential risks. Based on studies conducted after the catastrophes, the Japanese government revised its tsunami projections in a report posted on a government website. While the earlier forecast in 2003 put the potential maximum height of a tsunami runup at less than 20 m, a governmental panel of experts in Japan recently reported that the occurrence of a magnitude-9.0 earthquake in the Nankai trough, which runs east of Japan's main island of Honshu to the southern island of Kyushu, might generate a tsunami runup with a height of more than 34 m, which would inundate much of Japan's Pacific coast. A chronicle of Cheju Island (Tamraji) reports that a tsunami was propagated by the 1707 Hoei earthquake. The tsunami from the 2011 earthquake event was also propagated to the southern shore of Korea. In this study, we conducted a numerical simulation of the propagation of the tsunami from Japan's Pacific coast to the southern shore of the Korean Peninsula. Simulation results are presented for 11 scenarios of initial water displacement identified by the Japanese government. The simulation results indicate that after an earthquake in the Nankai Trough, tsunami waves would reach Cheju Island in approximately 3.5 hours and the southern coast of Korea in approximately 4 hours, with a maximum runup height of approximately 1.5 m.
Kim, K.O., Choi, B.H., Pelinovsky, E. and Jung, K.T., 2013. Three-dimensional simulation of 2011 East Japan-off Pacific coast earthquake tsunami induced vortex flows in the Oarai port.
The huge tsunami was generated by the 11 March 2011 off coast of the Pacific side of East Japan, recording a maximum 40 meter run up in Iwate prefecture. The tsunami wave attacked the Oarai port of Ibaraki prefecture within 30 minutes, and created an enormous vortex flow within the harbor. A similar feature was observed in the Imwon port, in the Eastern Korean coast during the 1983 tsunami event in the East (Japan) Sea. A set of simulations have been performed to investigate the generation of the powerful vortex caused by the 2011 tsunami event at the Oarai Port. The application of numerical models has successfully reproduced the formation of the vortex in the center of the port, which can be clearly identified in a photograph taken during the tsunami. The simulation of tsunami generation and propagation at the outer sea is performed with a hydrostatic model and, for the investigation of a more detailed transient pattern of water flows, the model which uses full Reynolds-averaged Navier–Stokes equations is applied. Examination of the Oarai and Imwon vortexes implies that the generation and strength of a vortex due to tsunami wave is strongly related in the size and the shape of port and breakwater layouts. The present work indicates that time-variation the inflow through the mouth of a harbor controls the transient pattern of the vortex.
Kim, K.-H., Shin, S., Widayati, A.Y.W., 2013. Mitigation Measures for Beach Erosion and Rip Current In: Conley, D.C., Masselink, G., Russell, P.E. and O'Hare, T.J. (eds.)
Korea has achieved both economical and socio-cultural developments in recent years, and in the midst of these changes, the issue of beach erosion has been recognized as one of the most important and controversial coastal problems in the country. Hence coastal protection is required which they have to be designed, constructed and maintained efficiently (Pilarczyk and Zeidler, 1996). This case study on beach erosion was conducted at Haeundae Beach in Busan, located in the south coast of Korea. Haeundae Beach is regarded as the most popular and beautiful urban beach in Korea. One of the main purposes of this study is to take comprehensive countermeasures to mitigate the beach erosion problem at Haeundae Beach. The historical investigations, field observations, laboratory experiments, and numerical simulations were conducted to understand the problems and to obtain solutions for countermeasures. The laboratory experiments of 3D hydraulic model tests qualitatively reproduced erosion patterns and rip currents that were shown in numerical simulations. The results of laboratory experiments showed improvements in the countermeasure plan using both beach nourishment and submerged breakwaters from erosion.
Kim, S.-W. and Suh, K.-D., 2013. Performance analysis of vertical breakwaters designed by partial safety factor method
The partial safety factor method has been developed in Europe, Japan, and Korea to overcome the limitations of the deterministic method for design of the vertical breakwater. The practical engineers prefer the partial safety factor method because this method is relatively simple to use compared with other probabilistic methods. However, the partial safety factor method does not evaluate the displacement of the vertical breakwater, while only defining the boundary between safety and failure domains within a given target safety level. Therefore, it is required to examine the performance of the breakwater designed by the partial safety factor method in terms of caisson sliding distance. In the present study, the partial safety factors developed by an advanced research for vertical breakwaters are used with the target reliability indices of 2.33 and 2.0. The performance analysis of 12 cross-sections of five vertical breakwaters was conducted by the method based on the Monte-Carlo simulation. Especially, this method considers a technique to eliminate the unrealistic extreme values of the design variables. As a result, the breakwaters designed by the partial safety factor method with the target reliability index of 2.0 are found to be stable except for one cross-section with high uncertainty of wave height. On the other hand, all the breakwaters with the reliability index of 2.33 are found to be stable irrespective of any uncertainty of wave height. Finally, it is found that the vertical breakwaters designed with the reliability index of 2.33 satisfy the allowable exceedance probabilities for both repairable and ultimate limit states.
Kim, Y.T. and Lee, J.I., 2013. Experiments on Seawater Exchange and Lee Side Stability of Breakwater.
This study deals with the performance of artificial seawater exchange structures and the lee side stability of the associated breakwater structures. Artificial seawater exchange structures are constructed with breakwaters to create circulation of the sea water. The tidal range under consideration from Approximate Lowest Low Water (App. LLW) to Highest Water Level (HWL) of this area is only 0.4 m, therefore, sea water circulation by tidal currents will be negligible. Various designs for structures which can force circulation of the inner harbor water are presented. These were quantitatively evaluated by using 2-D hydraulic model experiments. The results show that the seawater change structure is efficient for exchanging seawater at a rate of 1.5–4.3 m3/s for H s = 2–3 m. The measured damage of the rubble mound at the lee side of the structure due to overtopping is very severe. Various shapes of superstructure and of amour blocks were tested to reduce such damage. The main mechanism for reducing this damage is to ensure that any overtopping is returned to seaward and not to the lee side slope of the structures.
Lee, C.-E., Kim, G. and Kim, S. U., 2013. Stochastic reliability analysis of armor units of rubble-mound breakwaters under the multiple loads.
A stochastic reliability analysis model was developed for evaluating the time-dependent capacity variation of armor units of rubble-mound breakwaters subject to the multiple loads of arbitrary magnitudes which could occur randomly. The initial structural capacities and the damage rates of armor units of ruble-mound breakwaters was estimated as a function of the incident wave height with a given return period by using the modified Hudson's formula and Melby's formula. The structural capacity of armor units of rubble-mound breakwaters was also analyzed in detail through the lifetime reliability investigations according to the limit states such as the serviceability or ultimate limit state and the conditions of multiple loads. Finally, the repair intervals for the structural management was quantitatively evaluated by the present model that were developed by combining the target probability for repair and the accumulated probabilities of failure obtained from the present stochastic reliability analysis model.
Lim, H.S., Chun, I.S., Kim, C.S., Park, K.S., Shim, J.S. and Yoon, J.J, 2013. High-Resolution Operational Coastal Modeling System for the Prediction of Hydrodynamics in Korea Using a Wave-Current Coupled Model
We have developed a high-resolution operational coastal modeling system for the coastal waters of Korea using a wave-current coupled model ROMS. The operational oceanographic system consists of operational modeling and monitoring modules. The modeling system comprises atmospheric and hydrodynamic models coupled with three-dimensional hydrodynamics, wave, sediment transport, and water quality model. The hydrodynamic variables are forecasted on a 72-hour basis. The real-time monitoring system is comprised of buoy, HF-radar and geostationary Communication Ocean Meteorological Satellite (COMS). The web-GIS-based coastal information system provides predicted results with real-time monitoring data for dissemination to the public and validation of the predicted results. The operational coastal modeling system uses the ROMS hydrodynamic model coupled with SWAN, a wave model. WRF is used for meteorological modeling of atmospheric forcing, NAO.99jb is a regional tide model used for the tides, and CE-QUAL-ICM is an eutrophication model that is used for simulating the water quality. The atmospheric forcing is derived from the predicted results of the WRF atmospheric model, which has been operated for forecasting in the East China Sea and East Sea. The ocean boundary condition is derived from data-assimilative ROMS, which has been in operation for the Yellow Sea. The hydrodynamic variables were calibrated with tidal surface elevation and verified with current data observed by a bottom-mounted ADCP and AWAC. To validate the predicted results, we use real-time monitoring data from hydrodynamic measurements observed by the operational AWAC and buoy, 1-h averaged surface currents measured by HF-radar, and suspended sediment concentration (SSC) obtained hourly and derived from the Geostationary Ocean Color Imager (GOCI) of COMS. The wave-current coupled ROMS-SWAN modeling system shows enhanced wave-current interaction for the coastal waters of Korea, especially for the prediction of storm surge height and variation of suspended sediment transport. This operational coastal modeling system has been originally developed for the prediction system of coastal waters of Korea and used for the development of an Integrated-Maritime Prediction System (I-MAPS) supporting the operation of the major ports system of Korea such as Incheon and Gunsan on the western coast of Korea, and Yeosu, Masan and Busan on the southern coast of Korea. I-MAPS will also provide monitoring and predicted data to governmental agencies and to the public to support ship navigation and marine activity and to solve problems associated with coastal accidents, such as storm surge, inundation, search and rescue, and oil-spills, as a part of the Korea Operational Oceanographic System (KOOS) which will be in operation by the end of 2013.
Lin, T.-Y., and Liou, J.-Y., 2013. Lessons learned from two coastal dune reconstruction experiments in Taiwan.
Coastal dunes represent a natural barrier and play a vital role in the coastal defense against the waves and tides. Dune enhancement or reconstruction is considered to be a solution to avoid the negative effects on the ecological and aesthetic values of the coast by those engineering structures. Two field experiments were conducted for dune building at the Tainan coast in Taiwan. Experimental sets, including artificial vegetation, sand fence deployment and the bulldozed dunes with different surface pavements, were set up to re-build the foredune that have been previously damaged. A small natural remnant dune was chosen as the comparison set for evaluating the effectiveness of the sand accumulation and vegetation growth. The dune reconstruction processes were observed by monitoring the changes of dune profiles, surface sand grain size, and the vegetation density. The experiment results are used to suggest an appropriate dune rehabilitation procedure for this area. The results reveal that a bulldozed dune can raise the height immediately, and putting oyster racks on the bare surface can help the accumulation of sand and the colonization of vegetation that will quickly stabilize the artificial foredune. Sand surface covered with oyster shells may avoid wind erosion at the beginning, but it also hampered the vegetation colonization. Muddy sand surface formed a hard crust to reduce the wind erosion, but it also hindered the infiltration process that two gullies were found on the dune after a heavy rain. Sand fence should have an appropriate fence porosity to be effective.
Marcinkowski, T., Szmytkiewicz, M, 2013. Performance of submerged breakwaters as improvement of beach fill effectiveness in Gdynia, Poland
The study is focused on improvement of beach fill effectiveness due to construction of submerged breakwaters at an extremely sediment-hungry coastal segment, situated in the Gulf of Gdansk in Gdynia municipality. The studied coastal segment stretches over 500 metres between a cliff headland belonging to a local nature reserve and a walkway pier. The segment has been heavily eroded, resulting in disturbances to the operation of the wharf, as well as the local urban infrastructure. Geophysical records show that the sediment layer in the coastal zone hardly exists. To reduce the vulnerability of this coastal section a 3-segment submerged breakwater was constructed in 2006. It was situated 150 m offshore and the crest was positioned 0.5 m below MWL. The modeling was aimed at precise mapping of structures' effect and was carried out using MIKE 21/3. Bathymetric maps from 2005 – 2010 were used to verify the calculated sea bottom changes. The comparison of wave heights and water circulations, calculated both with and without the presence of the structures, showed that during storms the wave energy reaching the shore is reduced by 45% for the mean water level when the structures are present. For storm surges of 1.1 m the effectiveness of the structures is reduced to some 20%. For the mean water level the reduction of water circulation velocity is 20 – 25%. The presence of submerged breakwaters slow down the migration of sediment; the increase of residence time of beach fill was estimated between 15 and 20%.
Marzeddu, A., Gironella, X., 2013. Impulsive wave loads on rigid structure, an experimental approach
Within the European project ‘Hydralab IV', HyRes we aim to improve the characterization of wave loads on rigid structures and the associated response by carrying out some laboratory experiments. Wave loads on rigid structures are divided into quasi static loads and impact loads. If the physics of quasi-static loads due to waves is well known, this cannot be said the same for wave impact loads. A comprehensive method to design maritime rigid structures under impact loads does not exist yet and the actual design method suggests avoiding scenarios where impact loads can take place. In the last decade, some laboratory experiments have been carried out; however some questions remain still unanswered. The use of different sensors can lead to significant changes in the results and an “exhaustive comparison” between dissimilar types of sensors has not been done yet. Even the magnitude of these forces can be underestimated during a laboratory test just for the choice of sample frequencies which are too low. This paper describes the experiments performed on a small scale flume at UPC on a scaled vertical breakwater in order to compare the results of pressure transducers and force load cells. Moreover, a high frequency sampler (up to 20 KHz) was used in order to understand the importance of sample frequency on the magnitude of the results. A simplified scenario has been set up in order to make the data analysis easier.
Matsumoto, A., Mano, A., Mitsui, J., and Hanzawa, M., 2013. Armor block stability of submerged breakwaters predicted by numerical wave flume
Submerged breakwaters are one of the most fundamental structures to protect coastal areas from wave action. To ensure the stability of a whole structure, it is primarily important to determine the required mass of armor units accurately. This study aims to evaluate the armor block stability based on a flow field calculated by a numerical wave flume. The flow field was calculated by using a 2D VOF-type numerical wave flume. The wave force acting on an armor block was calculated using the Morison formula. Drag, inertia and lift coefficients for the Morison formula were determined by using an exact 3D VOF-type numerical model. The resultant stability of the armor block was judged from a comparison between the wave force and the stabilizing force originating from the mass of the armor block. An evaluation method for the critical condition of armor block stability of submerged breakwaters is proposed. Parameters for the evaluation were calibrated through comparisons between experimental and numerical results. An impact wave force with short duration acted when the water depth above the breakwater was shallow. In such a situation, even if the peak value was large, the impulse was not so large. To estimate the displacement of the block, the equation of the motion of the block was solved. The agreement between predicted and experimental stability was improved by using the fluid force coefficient corresponding to an individual water depth condition. That is to say, the applicability of the model was shown to have improved.
Mazaheri, S., Kamranzad, B. and Hajivalie, F., 2013. Modification of 32 years ECMWF wind field using QuikSCAT data for wave hindcasting in Iranian Seas
Hindcasting of long term wave characteristics is necessary for designing coastal and marine structures as well as other marine activities. For this purpose, numerical modeling is used for simulating the wave regime. Numerical wave modeling requires an accurate wind field with high temporal and spatial resolutions in a long period. In this paper, ECMWF wind field was firstly compared with QuikSCAT satellite measurements using wind roses. Despite the good agreement of dominant wind directions obtained from two wind sources in most locations, modification of ECMWF was performed for each component of the wind vector, separately for achieving more accurate wind field. Then, the modified ECMWF was utilized as numerical wave modeling input. Numerical wave model was SWAN and the models were calibrated and verified in each sea and the results show good consistency with the measured wave data.
Niroshinie, M.A.C., Suzuki, T. and Sasaki, J., 2013. Numerical modeling of bed profile evolution using Large Eddy Simulation
In the surf zone, turbulence and complex fluid motions due to wave breaking cause sediment suspension and movements. For the bed profile, the main causes of topography change are sediment pickup, suspension and settlement. Accurate modeling of the turbulence generated by the flow field is necessary for proper estimation of generated bed profiles. Until now, many types of numerical models, which can estimate bed profile evolution in the surf zone, were developed. Large Eddy Simulation (LES) model was used to estimate the flow fields due to the turbulence generated by wave breaking. The present model consists of a LES model coupled with a sediment pickup/advection model and a bed profile evolution model. The sediment pickup rate is calculated with the sediment pickup function using Shield`s number at the bottom. The sediment particles are 0.15 mm diameter and assumed to be moved with advection of flow field. The continuity equation for sediments is solved to estimate the updating bed. The updated bed is feedback to the hydrodynamics model. Numerical simulation results were compared with the experimental results for velocity vector fields and generated bed profiles. It was observed that, the experimental results of velocity vector fields are consistent with numerical results. Also it was found that, formation of bed profiles near breaking region and swash zone was significant both in numerical and experimental results.
Oguz, E., Elginoz, N., Koroglu, A., Kabdasli, M.S., 2013. The effect of reed beds on wave attenuation and suspended sediment concentration.
The effect of emergent and submerged vegetation on uniform and oscillatory flow conditions has been intensively studied by researchers in the last two decades. It has been determined that vegetation affects wave characteristics and cause wave attenuation especially in shallow waters where wave orbitals are in interaction with vegetation. Consequently they affect sediment deposition and resuspension acting as a sink. The aim of this study is to determine wave attenuation due to vegetation, and to identify the effect of emergent vegetation on suspended sediment concentration. In this experimental study, a reed bed was established on a sandy bottom in a wave flume in ITU Hydraulics Laboratory. Regular waves with different wave steepness were generated in the flume and water surface elevations through the reed bed were measured using resistance type wave gauges. Suspended sediment concentration time series were measured using OPCON along depth. The gradual wave attenuation due to reed bed was determined and wave transmission coefficients for different waves were found between 0.35 and 0.55 and these values are reversely proportional with wave steepness. It has been found out that wave attenuation also decreases with increasing KC numbers. Suspended sediment concentration measurements inside the reed bed were a little bit harder to interpret, but a decrease in concentration; before the waves reach the reed bed and after the waves left the reed bed, was determined. In spite of many studies on effects of vegetation on flow conditions there is still a lack of understanding vegetation-flow interaction and sedimentation around them. This study is an attempt to make a contribution on this topic.
Oudart, T., Larroudé, Ph. and Bouchette, F., 2013. Two numerical approaches: 2D and 3D SPH model to simulate extreme waves over a barrier island
The barrier islands usually erode seriously during the occurrence of typhoon, especially, when storm surge comes at the spring tide period. The high water level combined with typhoon wave run-up induces overwash on the barrier islands and pushes the barrier sand into the lagoon behind. . We tentatively characterize this natural phenomenon with numerical modeling of the propagation of water waves onto a barrier island. The modelling work is based upon 2D and 3D Smooth Particle Hydrodynamics (SPH) models. The barrier island response to typhoon waves is analyzed in two different ways: 1) comparing the results from an experimentation in a wave flume with those from SPH computations performed on exactely the same barrier island morphology and the same long wave forcings; b) performing SPH computations in a real case study, i.e. the Wan Lu Tziao barrier island, south-western Taiwan (ANR KUN-SHEN program), from the shoaling zone in the open sea to the lagoon.
Rahman, S., Mano, A. and Udo, K., 2013. Quasi-2D Sediment Transport Model Combined with Bagnold-type Bed Load Transport.
Suspended load and bed load sediment transport are important component for the sediment transport in surf zone. The purpose of this study is to obtain a good model for sediment transport in surf zone by combining a quasi-2D sediment transport model and the Bagnold-type sediment transport model. The quasi-2D sediment transport model is used to simulate the suspended load transport, while the Bagnold-type for the bedload transport. A quasi-2D numerical wave model called Funwave was expanded to accommodate the sediment transport model. The model is validated by the published data for sediment transport in a wave flume. Two mode of morphological change is compared to evaluate the influence of wave-current (mode A) and instantaneous bottom velocity (mode B) in the third and forth velocity moment of Bagnold-type sediment transport model. Four sets of bed load transport parameters are evaluated to calculate bed level change. The evaluation shows that although eB exceeds one, it can produce bed level change similar to that by using the parameters proposed by Bailard. Parameters proposed by van der Molen calculated very high bed level change, while Gallagher's parameter produced relatively small bed level change. The performance of two modes of morphological change shows that mode A produce much better morphological change than mode B in surf zone for the bedload transport component. While for the suspended load component, mode B produces very high erosion in surf zone. Coupling of mode B and a wave motion-induced suspended load transport gives comparable morphological change to the experimental data.
Rocha, M.V.L., Silva, P.A., Michallet, H., Abreu, T., Moura, D., Fortes, C.J., 2013. Parameterizations of wave nonlinearity from local wave parameters: a comparison with field data
Three different parameterizations of wave nonlinearity from local wave parameters are applied to field data (free-surface elevation and flow velocities) gathered in different beaches along the Portuguese coast, under diverse wave conditions. The hydrodynamics of the various sites are analyzed, together with the performance of each formulation. The data considered extend the range of the data previously used by the authors of the parameterizations, including longer wave lengths and higher Ursell numbers. A comparison is done, based on skill and agreement index values, to understand the performance and applicability of each parameterization and what could be changed to improve such formulations.
Saket, A., Etemad-Shahidi, A., Moeini, M.H., 2013. Evaluation of ECMWF wind data for wave hindcast in Chabahar zone
Wind waves are the most important environmental forces acting on the marine structures. Due to the incompleteness of measured wave parameters, wave prediction plays a key role in the design of coastal and offshore structures. Nowadays, numerical wind wave models are widely used for wave hindcast and forecast. Since wind is the most important forcing term in the numerical wind wave model, the selection of appropriate wind source is a vital step in the wave modeling. In the present study; two wind sources i.e. the measured synoptic and the ECMWF (European Center for Medium Range Weather Forecasts) data, were evaluated for wave simulation near the Chabahar zone. To simulate wave parameters the third generation spectral SWAN model was utilized and the results were compared with those of in situ measurements in a depth of about 17 m. The whitecapping dissipation coefficient and bottom friction factor were used for calibration of the model. The sensitivity analysis showed that other physical parameters have no specific effect on the wave characteristics. Calibration of whitecapping dissipation rate led to the overestimation of high waves. Therefore, a combination of whitecapping dissipation and bottom friction factors was used to calibrate the model. It was found that the SWAN model forced by ECMWF wind data predicted the south-west and west waves successfully while underestimated the east, south-east and south waves. This was mainly due to well prediction of south-west and west wind and underestimation of wind from the east to the south by the ECMWF model. In addition, it was revealed that synoptic wind data can be used as an appropriate wind source for wave hindcasting at the studied area.
Salvadori, G., Tomasicchio, G.R.., D'Alessandro, F. 2013. Multivariate approach to design coastal and off-shore structures.
A frequent statistical problem in many coastal and off-shore engineering situations is to estimate the probability of structural failure expressed in terms of Return Period and Design Quantile. Usually, an univariate analysis is carried out to quantify the risk of failure. However, coastal and off-shore structures typically fail because of the occurrence of a critical combination of all the variables at play in a sea storm: thus, it may be important to consider the joint occurrence of dangerous conditions. The present manuscript outlines an original approach, exploiting Copulas, in order to provide a consistent framework for the calculation of bivariate Return Periods and Design Quantiles, which can be generalized to the multivariate case.
Shim, J., Kim, J., Kim, D., Heo, K., Do, K., Park, S., 2013. Storm surge inundation simulations comparing three-dimensional with two-dimensional models based on Typhoon Maemi over Masan Bay of South Korea.
Severe storm surge inundation was caused by the typhoon Maemi in Masan Bay, South Korea in September 2003. To investigate the differences in the storm surge inundation simulated by three-dimensional (3D) and two-dimensional models, we used the ADvanced CIRCulation model (ADCIRC) and 3D computational fluid dynamics (CFD) model (FLOW3D). The simulation results were compared to the flood plain map of Masan Bay following the typhoon Maemi. To improve the accuracy of FLOW3D, we used a high-resolution digital surface model with a few tens of centimeter-resolution, produced by aerial LIDAR survey. Comparison of the results between ADCRIC and FLOW3D simulations shows that the inclusion of detailed information on buildings and topography has an impact, delaying seawater propagation and resulting in a reduced inundation depth and flooding area. Furthermore, we simulated the effect of the installation of a storm surge barrier on the storm surge inundation. The barrier acted to decrease the water volume of the inundation and delayed the arrival time of the storm surge, implying that the storm surge barrier provides more time for residents' evacuation.
Tomasicchio, G.R., D'Alessandro, F. 2013. Wave energy transmission through and over low crested breakwaters.
In the present paper, a formulation for the estimation of the wave transmission coefficient, Kt, at low-crested structures (LCS) is proposed based on a large laboratory database. The adopted database considers 2D experiments on wave transmission at LCS; it consists of 3327 values of Kt from 33 datasets and includes rubble mound structures with natural and concrete units, as well as impermeable slopes. According to Goda and Ahrens (2008), the wave transmission coefficient is formulated as the summation of the wave energy transmitted over and through LCS. Application of the new formulation showed a good agreement between measured and predicted Kt.
Tsung, W.S., Hsiao, S.C., Huang, T.Y. and Wu N.J. 2013. Simulation of propagation and run-up of landslide-induced waves using meshless method.
A two-dimensional numerical model using radial basis functions (RBFs) and collocation points for solving partial differential equations (PDE) is presented in this study. This method is a general meshless method called RBF collocation method. The basic concept of RBF collocation method is to approximate the solution for a PDE as a linear combination of RBFs. The feature of this method requires neither the domain nor the boundary meshes. The main framework is developed by Wu and Chang (2011), and is applicable for solving moving boundary problems with free surface wave. Different from the conventional RBF collocation methods that usually malfunction in the seeking of partial derivatives around the boundaries, the present model resolved the problems by additionally requiring the satisfaction of the governing equations on boundaries. The model validation is performed by comparing the present results of the submarine landslide induced-wave with other numerical solutions, such as BIEM (Lynett and Liu, 2002), a high-order Boussinesq-type model (Furhman and Madsen, 2009). Fairly good agreements are observed. Finally, the landslide-induced wave propagation and shoreline motion on three plane slopes are also discussed.
Valsamidis, A., Cai, Y., Reeve, D.E., 2013. Modelling beach-structure interaction using a Heaviside technique: application and validation
In this study, an analytical solution, based on a Heaviside technique, is developed to model the shoreline evolution in the vicinity of a groyne due to a random sequence of waves. The beach at Borth, Wales, UK was used as a case-study. A wave time-series covering a time period of about 12 years, was used to test the performance of a recently constructed coastal defence scheme. Transformations of the wave time-series from offshore to nearshore were performed using a semi-empirical procedure. Three different wave breaking formulae were independently applied to the wave model, and their effects to the consequent shoreline evolution were investigated. In addition, three different longshore transport formulae were compared. These were the CERC, the Kamphuis and the Bayram formulae. Results showed that the CERC formula predicted a significantly greater amount of sediment transport and hence erosion on the downdrift side of the groyne while the models based on Kamphuis and the Bayram formulae gave comparable results. All the results exhibited a strong sensitivity to the temporal resolution of the forcing. Finally, some sensitivity to the treatment of wave breaking was found.
Wu, Y.-T. and Hsiao, S.-C., 2013. Turbulence induced by a solitary wave propagating over a submerged object using particle image velocimetry.
We present an experimental study for solitary wave propagation over a submerged rectangular obstacle using the particle image velocimetry (PIV) technique. The PIV system, mainly consisting of a digital high-resolution camera and a dual-head pulse laser, is used to measure instantaneous free surface motion and corresponding velocity properties around the submerged object. Four fields of view (FOVs) are set in order to form a continuous flow fields around the structure. Quantitative mean properties are obtained by ensemble averaging 30 repeated measurements for each FOV. Therefore, the entire data of the time histories of the free surface elevation recorded by wave gauge is 120 sets, and the standard deviation (STD) for incident wave height is 0.61 mm or 1.3% of mean incident wave height. The experiments show high degree of repeatability. After gaining the mean velocity properties, the vorticity field can be calculated by taking curl of mean velocity field and the turbulent kinetic energy can be estimated from velocity fluctuations. It is found that the measured turbulence in the weather side is much larger than that in the lee side of object. A local maximum value of turbulent intensity in the weather side of object is about 63.4% of depth-averaged velocity as the crest of solitary wave approaches but not yet reaches the front edge of breakwater. On the other hand, a local maximum value of turbulent intensity in the trailing edge is around 37.1% of depth-averaged velocity.
Yoo, D.H., Yoon, J.J., Yoo, J., Lim, H.S., Choi, J.Y., 2013. Local parameter for armor weight estimation
A new surf parameter called the ‘wave action slope' is introduced to represent local wave conditions in shallow waters by employing local values of wave length or wave celerity and wave height. The use of wave theory on a flat bed of depth at the front of the breakwater might be considered far superior to the simple adoption of the deep water wave length for characterizing surfing waves at a shoaling depth. The wave action slope is formed by the product of the breakwater slope and the ratio of the celerity to the wave height. The optimum or minimum weight of the armor unit is related to the wave action slopes, which are employed for developing new empirical equations. Analyzing the laboratory data of van der Meer revealed that the armor weights are closely related to the wave action slope. By using the new surf parameter given with local parameter values, we suggest a simple but accurate equation to estimate the breakwater armor weight. Several empirical equations are applied to cases of failure experienced along the eastern coast of Korea. The values given by the Hudson equation are satisfactory for 26 of the 57 total failure cases. The number of satisfactory cases decreases by using recent empirical equations; of the 57 failure cases, the number of satisfactory cases yielded is 17 for the van der Meer/de Jong equation and 13 for the equation of the present study considering local parameters. The reduced number of satisfactory cases may indicate improvement of the new empirical equations over the Hudson equation.
Zhang, J., Zheng, J., Zhang, C., Jeng, D. and Guo, Y., 2013. Numerical study on the interaction between waves and twin pipelines in sandy seabed
In offshore engineering practice, the construction of an identical cylinder close to the existing pipeline may largely affect the near flow field and hydrodynamic forces on the pipelines. The interaction between incident ocean wave and twin pipelines in sandy seabed plays an important role in the design of submarine pipelines. A mathematical model based on the Volume-Averaged Reynolds-Averaged Navier-Stokes (VARANS) equations, a two-equation k-ϵ turbulence closure and an internal source term wave maker is adopted to describe this complex phenomenon. The sandy bed where the pipelines are partly buried is treated as a rigid porous material, and its impact on wave-pipeline interaction is considered in the VARANS model in terms of porosity and equivalent mean diameter of porous material. The impacts of burial depth and distance between the centers of twin pipelines on the wave-seabed-twin pipelines interaction are numerically investigated. The research results from numerical simulations indicate that the burial depth and relative position of twin pipelines significantly affect the wave-averaged flow velocity and dynamic pressure distribution.
Aagaard, T. and Sørensen, P., 2013. Sea level rise and the sediment budget of an eroding barrier on the Danish North Sea coast.
The barrier spit Skallingen on the Danish North Sea coast accreted significantly for a period of three centuries prior to 1970 but it is now strongly eroding and the average rate of shoreline recession is about 4.2 m/yr. The causes for the erosion are examined through a sediment budget approach and it is found that although mean sea level is presently rising at a rate of about 3.3 mm/yr, the impact of longshore sediment transport divergence is far more important to barrier erosion. Sediment losses from longshore transport gradients are partly offset by minor gains through onshore transport of sand across the shoreface as well as by beach nourishment. The results illustrate that the Bruun model (Bruun, 1962) is insufficient to predict coastal erosion and even though sea level rise may cause erosion, far larger erosion rates can be induced by indirect human impact. Moreover, since the barrier was formerly in an accretive state, the absolute magnitude of (some of) the sediment budget terms have clearly changed significantly during recent decades, and using a numerical model it is found that longshore sediment losses have increased by a factor 3–4 over the past century. This increased rate/gradient of longshore sediment transport has been due mainly to inlet channel dredging which degraded the ebb tidal delta that earlier sheltered the downdrift end of the spit.
Balouin, Y., Tesson, J. and Gervais, M., 2013. Cuspate shoreline relationship with nearshore bar dynamics during storm e events – field observations at Sète beach, France.
Cuspate shoreline or megacusps, having alongshore lengths of 100–1000 m, are features widely described, and several theories were proposed for their formation and evolution (edge waves, self-organization). Their dynamics is often related with rip-currents migration, crescentic nearshore bars evolution, even if the relationship between shoreline rhythms and inner-bar pattern appears to be extremely variable. An Argus video monitoring system was deployed in 2011 at Sète beach (French Mediterranean). This microtidal wave-dominated environment is characterized by the presence of a double crescentic nearshore bar and a cuspate shoreline with a 400 m wavelength. Wave climate is moderate at this site and most of the significant morphological evolution is observed during storm events. Monitoring of bar and shoreline evolution during two particularly energetic periods (autumn 2011 and spring 2012) permitted to evidence very different behavior in the coupling between bar and shoreline rhythms. Usually, a phase coupling is observed between bar shoals and a seaward bulge in the shoreline. However, during and just after an event, evolution and its timescale is variable for both morphologies, resulting in an apparent out-of-phase relationship. A storm group in autumn yields an important migration of the crescentic bar (200 m/day), due to an oblique wave incidence. However, shoreline cusps remained stable and migrated progressively during the storm fall. It took more than 10 days for the shoreline oscillations to recover a phased position with the bar shoals. In some occurrences, the bar displacement was rapidly reversed by a new event with opposite wave direction, and no shoreline migration was observed, probably because time was not long enough to observed a significant displacement. During the spring's storms, less energetic, a lower bar migration was observed (around 50 m), and a very small shoreline movement is seen, mostly due to the erosion of the flank facing incident waves. After this event, wave conditions decreased rapidly preventing any morphological evolution of both bar and shoreline. These observations indicate that the coupling between crescentic nearshore bars and shoreline rhythms is time-dependent, and a given period with significant energy on the falling storm is needed to recover a phased position of both morphologies.
Bond, J., Green, A.N., Cooper, J.A.G. and Humphries, M.S., 2013. Seasonal and episodic variability in the morphodynamics of an ephemeral inlet, Zinkwazi Estuary, South Africa.
The inlet dynamics of estuary and lake systems with ephemeral inlets have been little studied compared to systems with semi-permanent tidal inlets. Here we document the meso-scale dynamics of a barrier and its associated ephemeral inlet. The inlet is typically open during the rainy season and experiences closure during winter low flow periods. It does not migrate. The inlet is formed by fluvial overtopping of the barrier and when active, forms a small delta seaward of the channel and a small flood tide delta in the back-barrier. The tidal prism is insufficient to maintain the inlet and it is quickly sealed through wave-reworking of sand from the ephemeral delta when fluvial discharge diminishes. During a large ocean swell event coupled with abnormally high tides in 2007, a departure from this seasonal behaviour occurred. The barrier migrated 100 m landwards and formed a gently (1.74°) seaward dipping sand sheet. Whereas the barrier had previously been narrow, it was widened by 80 m and rose 1.5 m in elevation. A breach later occurred and rapidly migrated northwards, establishing a significantly deeper inlet. This closed following wave reworking of a large ephemeral delta. Since then the barrier has maintained its landward position yet the inlet has continued to function as it did prior to the storm surge. This episodic barrier retreat appears to represent crossing of a morphodynamic threshold that triggered historically unprecedented rates of barrier rollover, creating a new set of inlet morphodynamic processes. These were short-lived and the system appears to have reverted to the typical seasonal morphodynamic processes despite such rapid rollover.
Bradbury AP, Cope SN, Wilkinson C and Mason TE, 2013. Regional patterns of changing beach morphology at a decadal scale
The Southeast Regional Coastal Monitoring Programme commenced in 2002 and is on-going. In excess of 1000 km of open coast and estuarine shoreline are monitored at high resolution with a number of tools and at a range of spatial and temporal scales. The programme provides input to flood and coastal erosion risk management at a range of scales, from region-wide shoreline management plans, to detailed and localised geomorphological assessments. Detailed baseline surveys are repeated typically once every 5 years and three full surveys exist now for the entire coast. Sampling of the baseline surveys is conducted typically at biannual temporal interval. Annual analysis is conducted summarising coastal changes within coastal sub cells at a scale of typically 10–100 km. All data from the project are currently freely available via the project website ( www.channelcoast.org). Examples are used to illustrate the challenges associated with analysis of coastal geomorphological change over decadal and annual temporal scales. Differentiation between natural coastal processes and management practices are explored.
De Santiago, I., Morichon, D., Abadie, S., Castelle, B., Liria, P. and Epelde, I., 2013. Video observation of the morphodynamics of nearshore sandbars on a partially engineered embayed beach.
Embayed beaches are prevalent environments along the northern Spanish coastline. The present work analyses the temporal and spatial variability of nearshore sandbars on the pocket beach of Zarautz using daily video observations over 2 years. This partially urbanized beach can be divided into two well defined distinct areas: a natural section backed by a sand dune system to the East and an engineered section with rigid seawalls to the West. The objective of the present work is to evaluate if the engineered and natural sections of the beach present different morphological behaviors. The video image analysis was performed in two steps: First, sand bars were characterized visually and classified following standard classification schemes. Then, the outer sand bar migration was measured using automatic bar detection. Results show that the nearshore sandbars evolution covers a wide range of temporal and spatial variability. A noteworthy exception is the persistent presence of headland rips. The beach is mostly double-barred, with both bars able to go through all the states within the intermediate classification. The most common double bar morphological configuration is an inner low tide terrace coupled to well-developed megacusps, with an outer subtidal crescentic bar. Various preferred locations of rip channel formation are identified along the beach, suggesting that the effects of the headlands can propagate far away from the headlands towards the center of the embayment. Interestingly, the western engineered and more sheltered section of the beach sometimes exhibits a different beach state to that of the eastern section.
Dillenburg, S.R., Barboza, E.G., Tomazelli, L.J., Rosa, M.L.C.C., Maciel, G.S., 2013. Aeolian Deposition and Barrier Stratigraphy of the Transition Region between a Regressive and a Transgressive Barrier: an example from Southern Brazil.
The transition region between regressive and transgressive barriers on the northern and central coastal sectors of Rio Grande do Sul (RS) in southern Brazil is represented by a 170 km long stretch of coast where the barrier shows a general aggradational/stationary (a/s) behavior on a long term time scale. In this study, approximately 50 km of this transition region was analyzed at four sites: Tramandaí, Jardim do Éden, Cidreira and Dunas Altas. All barriers began forming around 7.8 - 7.2 ka. The northernmost site (Tramandaí) has a typical a/s stratigraphy, and barrier morphology is dominated by transgressive dunefields. Ten km to the south, at Jardim do Éden, the barrier shows a transgressive stratigraphy, and barrier morphology is also dominated by transgressive dunefields. At Tramandaí the maximum barrier height is around 4 m, with a maximum of 6 m, while at Jardim do Éden it averages 6 m, with a maximum of 11 m. Further to the south, 10 km from Jardim do Éden, the barrier at Cidreira shows a dominant transgressive stratigraphy developed in the last 7 ka, but with evidence of a relatively small regression (~600 m). Barrier height averages 10 m, reaching 20 m due to the existence here of a large transgressive dunefield. And finally, at around 30 km to the south of Cidreira, the a/s barrier of Dunas Altas occurs. Barrier morphology here is dominated by transgressive dunefields, with a surface height of around 8 m, but fronted by the largest and highest foredunes (around 8–10 m) in Rio Grande do Sul. The Dunas Altas coastline has regressed around 600 m in the last 7.8 ka. The Holocene barrier analyzed in this study, along a 50 km segment shows a general a/s behavior in the last 7.8 ka. The long time of a relatively stationary condition allowed the barrier to grow vertically by accumulation of aeolian deposits of at least four phases of transgressive dunefield development.
Earlie, C.S., Masselink, G., Russell, P.A., and Shail, R.K., 2013. Sensitivity analysis of the methodology for quantifying cliff erosion using airborne LiDAR – examples from Cornwall, UK.
The widespread problem of coastal cliff erosion and the management of the risk to infrastructure and property calls for robust quantification of cliff erosion rates. Quantification of sea-cliff rates of retreat on an annual to decadal time scale has typically been limited to rapidly eroding soft rock coastlines. This study uses airborne LiDAR technology to estimate cliff volume changes in hard rock environments to determine linear retreat rates. One epoch of LiDAR data was analysed (2007/2008–2010/2011) for ten sites around the coast of the southwest of England (Cornwall), selected due to the spatial variability in regional morphological processes, lithology and wave climate. Quantifying cliff recession rates using two LiDAR-derived Digital Elevation Models (DEM) requires selection of an elevation change threshold, below which the morphology is assumed to have undergone no significant change, referred to as the ‘vertical change threshold'. The errors inherent in using LiDAR and the various thresholds at which the data could be evaluated were tested. Linear rates of retreat were found to vary according to the threshold of error chosen, providing decreasing rates with an increase in threshold above 0.2–0.3 m. The rates of retreat observed at some low energy sites was of the same magnitude and in some cases lower (0.01–0.03 m yr−1) than the threshold of error inherent in the LiDAR data (0.03–0.1 m). The results were compared with the rates of retreat obtained from analysis of historic maps in Shoreline Management Plans which are non-statutory strategic assessments of the risks associated with coastal erosion that ultimately inform local and regional policy. Analysis of coastal erosion using LiDAR data tended to highlight the localised failures that occur episodically and which are averaged out in the rates derived from longer term analysis of historic maps.
Fernàndez-Mora, À., Calvete, D., Falqués, A., Ribas, F., and Idier, D., 2013. On the Predictability of Mid-term Cross-shore Profile Evolution
The aim of the present study is to analyse the mid-term beach profile evolution, considering the hypothesis that the alongshore processes can be neglected for the prediction of the mean profile evolution. To this end, a process-based model for the evolution of the cross-shore profile has been used. The model describes feedbacks between waves, rollers, depth-averaged currents and bed evolution, accounting for the effects of wave skewness and asymmetry on sediment transport. Offshore waves and tides conditions and bathymetric profiles measured at the FRF-USACE Duck are used to simulate a mid-term (72 days) onshore sandbar migration event. The model results agree with observed onshore movement and growth of the sandbar due to the inclusion of the intra-wave oscillatory flow with the skewness and asymmetry effects. The best predictions belongs to the averaging of the modelled evolution of individual cross-shore profiles that is better than the evolution of the mean cross-shore profile since. it takes into account the alongshore variability of the cross-shore profiles. These two methods result on better predictions than the individual profiles during the entire event.
Freire, P., Jackson, N.L. and Nordstrom, K.F., 2013. Defining beaches and their evolutionary states in estuaries
Projected rates of global sea level rise and human pressures have increased attention to the potential for landform change in estuaries. This paper assesses the status of the fetch-limited beaches in the Tagus estuary, one of the largest estuaries in Europe, with a focus on distinguishing active beaches from inactive vegetated banks and identifying conditions under which they change state. A total of 26 beaches were identified in the inner estuary and 49 in the tributary basins on 2007 aerial photographs and compared with conditions on older photographs (1944–1958). Lengths, widths and maximum fetch distances for beaches were measured and site visits were made to determine their origins and present conditions. Beaches occur at eroding uplands or marshes or on spits extending from eroding uplands. Human-created beaches occur on spoil areas, within niches formed by structures and where vegetation is eliminated or prevented from colonizing (e.g. boat launches and recreational surfaces). Basin infilling, with increase in the elevation of low tide terraces and the formation of bars, is reducing wave energies, and some beaches are reverting to vegetated banks. Beaches that become vegetated banks because of human actions occur where use for boating or recreation is abandoned and where spits that form off spoil deposits reduce fetch distances upwind.
Ganesh, R. and Gopaul, N., 2013. A Predictive Outlook of Coastal Erosion on a Log-Spiral Bay (Trinidad) by Wave and Sediment Transport Modelling
Coastal erosion is increasingly becoming a significant concern (economic and recreational) on considerable stretches of Trinidad's coastlines. Modelling investigations were undertaken into the impacts of time varying wave climates on coastal stability issues on Guayaguayare Bay, SE Trinidad. Erosion is currently occurring at an approximate rate of 0.6m per year (8-yr average). By utilising a wave dataset of approximately 5 years collected at both offshore and nearshore locations, a good appreciation into incoming wave energy was gained. Wave transformation modelling was carried out using DHI's MIKE21 SW. Increases in wave energy were found to be directly influenced by the North Atlantic winter storm period. Therefore, some variance in erosion rates, at different times of the year exists. Sediment transport across the bay was investigated using MIKE21 ST and LITDRIFT to determine volume variations. By using MIKE21 SW, transformed wave parameters at the shoreline were accurately obtained. Certain high risk zones were therefore identified as related to on-going coastal erosion. An insight into the seasonality of sediment transport processes (wave driven) taking place along this bay is now better understood but given a longer dataset more accurate quantifications can be made. Finally, net erosion/accretion zones were identified which can aid the coastal engineer/manager in making future infrastrucutural development decisions.
Garcin, M., Baills. A., Le Cozannet, G., Bulteau, T., Auboin, A-L., Sauter, J., 2013. Pluri-decadal impact of mining activities on coastline mobility of estuaries of New Caledonia (South Pacific)
This work aims at analysing the relative impact of sedimentary supply by rivers versus the effect of sea level rise and other processes over the last 5 decades of some representative coastal stretches of New Caledonia (South Pacific Ocean). The study of twelve coastal estuarine stretches has shown erosion rates ranging from −1.8m/y to accretion rates up to 5.5m/y over the last 50 years. During this time, the climate component of sea level rise has been evaluated around 0.5mm/y in Nouméa and can be considered identical on the studied island. Vertical movements affecting New Caledonia are suspected to be different between western and eastern parts of the island. Nevertheless, in areas with homogeneous vertical movement, the coastal stretches studied show various evolution rates. The analysis of accreting estuarine coastal areas shows that this evolution is linked to sedimentary supply from rivers. On New Caledonia Island, the creation of bare soils by nickel mining during the last 50 years has increased erosion processes on the watersheds and the solid discharge of the rivers. The study shows a strong correlation between the percentage of bare soil surfaces (up to 3.7 % of the watershed surface) generated by nickel mining and the coastline evolution rate (from −2m/y to 4m/y) around the estuaries of each watershed. Therefore, mining activity on watersheds is suspected to have been the major forcing factor of recent coastal changes during the last fifty years.
Guisado, E., Malvárez, G. and Navas, F., 2013. Morphodynamic environments of the Costa del Sol, Spain.
The morphodynamic environments of the Costa del Sol, in southern Spain, have never been investigated at a littoral cell scale. In the last half of the 20th century the tourism industry have transformed the coastal landscapes and, importantly, the natural processes inducing irreversible damages and changes. For the most part, a project-based view on engineering works has focussed on individual beach behaviour, but no assessment on morphodynamics has been reported at physiographic scale. Using an integrated modelling approach, which combines wave energy propagation and digital terrain integration (land and sea), in this paper a new characterisation of coastal morphodynamics for western Costa del Sol is presented. Methodologically, the challenge of integrating land and sea has been overcome using existing methods, which takes high-resolution interoperable bathymetric models of the continental shelf of this section of the Mediterranean, and couples it with the Official Digital Terrain Model. This allows for propagation of waves from deep water to realistic nearshore environments. Wave input is represented by wave spectra from the recording network of the Spanish Port Authority, and the wave propagation model SWAN is used to propagate wave parameters onshore. Given the variability of wave climate in the region, characterised by long periods of calms (over 77% per year) followed by high energy events (dominated by high frequency storm waves with periods of less than 7 seconds and maximum wave heights exceeding 5 metres), a wave power index is used to identify and provide input data for extreme wave conditions of great significance for beach morphodynamics in the region. Results show that at littoral cell scale, even in the presence of the steep nearshore (i) the adaptation of the system tends towards generating dissipative environments, (ii) the presence of abrupt changes in local bathymetry affects significantly wave orbital velocities even at depths beyond wave base potentially inducing nearshore sediment transport, and (iii) high energy events affect the coastal stretch in complex ways, where highly active short-crested/high-frequency wave conditions induce transitional morphodynamic states.
Harris, D.L. and Vila-Concejo, A., 2013. Wave transformation on a coral reef rubble platform
Wave transformation across coral reef platforms is the primary process affecting changes in coral reef geomorphology. Transformation regulates the amount of wave energy entering reef systems, however there have been relatively few hydrodynamic assessments conducted on coral reefs when compared to siliciclastic environments with the effects of common geomorphic features like rubble platforms on wave transformation never specifically examined. This study focuses on the changes in wave characteristics across a rubble platform in a high energy environment (One Tree Reef, southern Great Barrier Reef). Wave conditions were measured at five locations over two days along a cross-reef transect from the reef rim to lagoon. Most of the wave energy was dissipated during wave breaking with energy attenuation due to bottom friction a secondary process. Wave energy attenuation was between 60–99% of the offshore wave conditions only during high tide would wave propagation across the reef platform be capable of affecting reef geomorphology. The wave spectrum also changed with the shorter period gravity wave energy (3 – 20 s) almost completely expending during transformation while longer period infragravity waves (20 – 300 s) were capable of propagating across the reef platform. Wave heights were depth limited and primarily controlled by water depth which suggests that water depth over the reef platform and subsequently elevation of the reef platform above mean sea level govern the amount of wave energy transferred across into reef systems, with most of the gravity wave energy removed during propagation over coral rubble platforms.
Jayson-Quashigah, P-N., Appeaning Addo, K. and Kufogbe, S.K., 2013. Shoreline monitoring using medium resolution satellite imagery, a case study of the eastern coast of Ghana.
Shoreline change analysis provides important information upon which most coastal zone management and intervention policies rely. Such information is however mostly scarce for large and inaccessible shorelines largely due to expensive field work. This study investigated the potential of medium resolution satellite imagery for mapping shoreline positions and for estimating historic rate of change. Both manual and semi-automatic shoreline extraction methods for multi-spectral satellite imageries were explored. Five shoreline positions were extracted for 1986, 1991, 2001, 2007 and 2011 covering a medium term of 25 years period. Rates of change statistics were calculated using the End Point Rate and Weighted Linear Regression methods. Approximately 283 transects were cast at simple right angles along the entire coast at 200m interval. Uncertainties were quantified for the shorelines ranging from ±4.1m to ±5.5m. The results show that the Keta shoreline is a highly dynamic feature with average rate of erosion estimated to be about 2m/year ±0.44m. Individual rates along some transect reach as high as 16m/year near the estuary and on the east of the Keta Sea Defence site. The study confirms earlier rates of erosion calculated for the area and also reveals the influence of the Keta Sea Defence Project on erosion along the eastern coast of Ghana. The research shows that shoreline change can be estimated using medium resolution satellite imagery.
Kim, T.R and Lee, J.H., 2013. The difference in wave environments between intertidal sand beaches and mud flats.
The characteristics of wave environments are studied and compared between an intertidal beach and a mud flat. The Mohang Beach is an intertidal sand beach, located on the southwest coast of Korea with tidal range of over 5 meters. Strikingly, it lies just next to the large intertidal mud flat. In order to find the wave energy difference between the intertidal sand beach and mud flat, a numerical wave model is performed with same boundary input conditions, and a wave directional spectrum is calculated at the entrance of each site. Unstructured grids for numerical wave model are used because the details of the shore orientation and topography are important to simulate wave propagation and shallow water effects in nature. It is found that the sand beach is more exposed to the wave forces than the mud flat in all wave directions. The field measurement also shows higher wave heights at the sand beach than the mud flat. The local difference of wave propagation and energy is the main factor maintaining the two adjacent environments with disparate sedimentological characteristics.
Kim, C.H., Park, J.W., Lee, M.H. and Park, C.H., 2013. Detailed bathymetry and submarine terraces in the coastal area of the Dokdo volcano in the Ulleung Basin, the East Sea (Sea of Japan).
In the northeastern part of the Ulleung Back-Arc Basin, the East Sea, the Dokdo volcano anomalously emerges, rising abruptly from the sea floor (~2,100 m below sea level). It is lying as a cluster of emerged small islets surmounting a larger submerged volcanic edifice. In order to investigate the detailed bathymetry and morphologic characteristics around the volcano's underwater guyot type summit, we carried out multi-beam surveys from 2006 to 2011 and analyzed the data. From the near islets to ~30 m depth, the flank slopes are very steep and irregular, overlain by sunken rocks, indicating partial erosion and talus formation due to waves, currents and weathering. The area from ~30 m to ~80 m depth shows gentle rises and falls, with a modest slope. Below ~80 m, the bathymetry gradually transitions to a relatively flat undulation with a smooth slope, extending to offshore areas. The bathymetry and the seafloor image from backscattering data show that there are small islets of the Dokdo volcano and a rocky sea bottom elongated from the islets, probably originating from residual parts of the eroded and collapsed main crater of the volcano. The seafloor images identify typical rocky bottoms, like rocky protrusions, and less sediment around the survey area, except for some areas with shallow sand sedimentary deposits. The stepped slopes of the study area are interpreted to be wave-cut submarine terraces rather than terraces from other origins, based on their relatively flat morphology and lack of sediments. The submarine terraces suggest a repetition of sea level changes (transgressions and regressions) in the Quaternary.
Kroon, A., Kabuth, A.K. and Westh, S., 2013. Morphologic evolution of a storm surge barrier system.
Morphologic evolution of a barrier island system on the southern shore of Zealand, Denmark shows regular inlet breaching and inlet closing over the last centuries. At the same time, the barrier slowly moves in a landward direction at its most exposed stretches. Alongshore wave-driven processes cause shoreline alignment and closure of inlets. A combination of high-energy waves and high water levels induces inlet breaching and overwash processes over the barrier crests. However, local high water levels are often not correlated with storm events in the inner Danish coastal waters. The water level fluctuations along the southern shore of Zealand are strongly influenced by the water level fluctuations in the Kattegat due to wind set-up and seiches in the Baltic Sea; local wind set-up and local wave set-up on the southern shore of Zealand are often of secondary importance. Statistics on extreme water levels based on measured water levels over the last century are often used to express the risk for flooding in a coastal environment. The present study indicates that this approach cannot directly be used in case of coastal erosion and inlet breaching. Extreme water levels and associated exceedance curves may overestimate these risks in cases of de-coupled extreme water levels and storm events.
Jeong-Min Lee, Jun-Yong Park, Jin-Yong Choi, 2013. Evaluation of Sub-aerial Topographic Surveying Techniques Using Total Station and RTK-GPS for applications in Macro-tidal Sand Beach Environment.
Accurate documentation of monitoring beach topographic changes is an essential component of coastal process research and management. Thanks to rapid development of technology, accuracy and quality of recent beach land surveying data have improved accordingly. As increasing demand for detailed beach topography, the adoption of a proper survey design and data collection strategy is also a crucial factor in order to collect high-density data accurately and efficiently within a given time. Especially, an efficient topographic surveying technique, by which the required time and manpower for a survey can be minimized, should be considered in the case of macro-tidal beach environment having a limited daytime for surveying the exposed intertidal zone. As a part of the Coastal Erosion Monitoring And Prediction (CEMAP) system development program of the Korea Institute of Ocean Science and Technology (KIOST), we conducted accuracy and efficiency tests for four different beach-profile surveying methods of: 1) spot measurement using a total station; 2) spot measurement using a RTK-GPS system; 3) continuous walking measurement using a RTK-GPS backpack system; and 4) continuous measurement using a RTK-GPS system mounted on an all-terrain vehicle (RTK-GPS ATV system) at the Gosapo macro-tidal sand beach, South Korea. Test results indicate that the RTK-GPS spot measurement method have the lowest vertical error of about 2 cm, which includes equipment and operation errors, while the rest of them have similar vertical errors with a range of 3 - 6 cm. In terms of survey efficiency, the RTK-GPS ATV system have advantages in surveying time and operational manpower with a reasonable vertical error of about 3 cm over the other surveying methods. As a result, The RTK-GPS ATV system is the most suitable surveying method for examining the beach volume and morphologic changes in a macrotidal sand beach, while the spot measurement methods using the total station or the RTK-GPS system are adequate for accurate beach-profile change analysis.
Lopes, V., Baptista, P., Pais-Barbosa, J., Taveira-Pinto, F., Veloso-Gomes, F., 2013. DGPS based methods to obtain beach cusp dimensions.
Statistical correlations between wave parameters and cusp dimensions other than spacing may provide insight into which processes intervene in beach cusps formation and evolution. However, there is little information about cusp dimensions such as cusp depth, height or elevation. The aim of this work is to evaluate and compare different methods to determine beach cusp dimensions in order to assess which one produces more accurate, extensive and easy-to-achieve results. For this purpose some beach surveys were carried out at Ofir beach, located on the Portuguese west coast. Each one of the methods uses different sampling and processing strategies to obtain beach cusp dimensions. In method 0 cusp dimensions were determined using only two tape measures. The remaining 4 methods use Differential Global Positioning System (DGPS). Methods 3 and 4 provide values for cusp spacing, height, elevation and depth whilst methods 1 and 2 provide values for the first three parameters only. If one is only interested in measuring beach cusp spacing, height and elevation, then method 1 seems to be more adequate, due to its ease in sampling and in dealing with the data processing. Values of spacing, height and elevation obtained via Method 1 are the most accurate ones. On the other hand, if one wishes to perform a more detailed analysis, including parameters other than the above-mentioned and, for instance, to produce Digital Elevation Models (DEM), a combination of Method 1 and Method 3 or 4 is more appropriate.
Lopes, V., Freitas, M.C., Andrade, C., Taborda, R., Ramos, R. and Oliveira, M.A. 2013. A GIS-assisted reconstruction of the Holocene transgressive paleosurface of Pederneira lowland (W Portugal)
The Last Glacial Maximum low stand and coeval re-incision of the Portuguese hydrographic network created the space and defined the shape of the main morphological features available to accommodate the inundation resulting from the Holocene transgression and the marine sediments deposited in tune with changing base levels. The reconstruction of the transgressive paleosurface is relevant in paleoenvironmental studies, namely to establish the paleobasin morphology and evaluate accommodation volume. In the case of the study area (Pederneira lowland), the geological data set available to reconstruct that surface consists of borehole logs carried out for geotechnics and groundwater and three cores performed for paleoenvironmental reconstruction. The borehole data scatter non-uniformly across the lowland providing spatially biased information. The surveying of several Transient Electromagnetic Method (TEM) profiles yielded inconclusive results in separating sediment units below and above the transgressive surface due to poor contrast in sediment resistivity and high conductivity of groundwater. This study addresses a method for estimating that paleosurface using the combination of a standard geostatistical interpolation procedure (kriging) with a conceptual geomorphological model. The geomorphological model comprised the sketching of a paleoriver drainage system in which the position of the thalwegs was defined departing from present-day slope morphology and depths estimated by adjusting a mathematical curve describing their longitudinal profile to control points. Final adjustments to the paleodrainage system were constrained by borehole data and expert judgment. This methodology proved to be effective in an area where limited objective geological and geophysical data are available.
Orviku, K., Tõnisson, H., Kont, A., Suuroja, S. and Anderson, A., 2013. Retreat rate of cliffs and scarps with different geological properties in various locations along the Estonian coast.
Recently reported increased water depths and greater wave heights, perhaps associated with increased storminess, are likely to lead to more active changes, such as increased beach erosion, faster shoreline migration and sediment redistribution. A coastal environment particularly sensitive to the impact of sea-level rise is that of highly erodible cliffs and scarps. As structures are often built close to such formations, it is important to determine the retreat rate of cliffs and scarps. Among other things, knowing the retreat rate can help regulators plan coastal protection measures and can help property owners decide where to place their structures to avoid damage. The principal objective of the current study is to find and analyze the retreat rate of cliffs and scarps in several locations along the Estonian coast. Variable geological conditions, exposure to the sea and human influence are considered. The study was carried out in five different locations along the Estonian coast representing different geological properties, variable human influence and hydrodynamic conditions. Aerial photographs, orthophotos, RTK-GPS, leveling survey and archive data was used to measure the changes on the edges of the scarps and cliffs. It was found that the fastest rate of retreat appears on the location where the softest sediments are exposed to the roughest wave conditions – in Cape Kiipsaare. Here the yearly scarp-line retreat reached over 7 m/y (17 m3/y per meter of shoreline) which is faster than the fastest retreat rate of soft cliffs recorded anywhere else, but still two times lower in terms of the eroded volume of sediments.
Péron, C., Chatelet A., Gensac E., Gardel, A ., 2013. Mud bank migration from remote sensing and bathymetric data: The example of the Kourou River Estuary, French Guiana (South America)
In French Guiana, the coastal mud banks dynamics, specially the intertidal part, have been largely studied while the subtidal expansion suffers a lack of knowledge. The subtidal area requires significant study in order to understand the complete processes of mud bank migration.
The aim of this short paper is to compare the mud bank migration in the subtidal area combining remote sensing data and in-situ measurement. The determination of the delimitation of the subtidal part is realized with remotely sensed data using waves attenuation as a proxy of the subtidal part location. Waves are dampened by fluid mud at proximity of the subtidal area, and are highly detectable on SPOT images. The regular bathymetric survey of the Kourou harbor channel offers a detailed situation of fluid mud arrival along the channel and so on the subtidal migration of the mud bank. Fresh mud arrival in the Kourou channel induce significant depth addition, more precisely the mud lens, important dredging effort in the navigation channel is organized to allow the passage of ships. Therefore, it is observed that the passage of mud bank contributes differently along the channel with a more pronounced arrival of fluid mud in the offshore part of the navigation channel between 2003 and 2009 while the onshore channel were silting-up by the trailing edge of the mud bank from 2010. Combining both the mud bank position from remote sensing images analyses and mud lens surveys allow the determination of the localization of a mud bank along the Kourou coast for 10years.
Preoteasa, L., Vespremeanu-Stroe, A., Hanganu, D, Katona, O.,Timar-Gabor, A., 2013.
Histria (Istros) is a Milesian colony founded on the Black Sea coast during the 7th c.BC. Nowadays, the remains of the ancient city are located 8 km inland form the Black Sea coast, on the continental edge of the Razelm-Sinoe lagoon system which forms the southern part of the Danube Delta. Significant environmental changes occurred during and after the ancient city's lifetime, particularly related to dramatic shoreline displacement. The present study deals with the Late-Holocene coastal landscape transformation from the open-coast stage to the present-day lagoon system. Our research includes stratigraphic records by Ground Penetrating Radar scanning of the beach ridges, cores in lagoons and beach ridges and absolute age determination of the paleoshorelines. The study shows that the ancient city decoupling from the sea was due to the beach ridge plain development southward and eastward of the acropolis. The decline of the Histria city, documented during the 7th c. AD, temporally coincides with the decoupling of the city from the open coast as a consequence of the shoreline progradation. Discontinuous chronology and discordant stratigraphy obtained by OSL dating and GPR scanning of successive ridges document intense neotectonic movements which affected Saele-Chituc beach ridge plain. The seismic activity led to the recent drowning of its central part and the formation of the Sinoe lagoon; the same processes acted at the downdrift part of the Dunavat lobe and also in the areas presently occupied by Histria and Nuntasi Lakes. Several areas containing archeological remains are currently below sea-level due to local neotectonics.
The coastline of the Rio de Janeiro is dominated by coastal sandy barriers which the main aspects of Quaternary evolution is determined by sea level oscillations in the Pleistocene and the Holocene. Such barriers have been studied in terms of geomorphological mapping, sediment transport and detailed morphology, mainly in the Holocene barrier. This work pretend by using geophysical techniques, describe the characteristics in subsurface of the coastal plain in part of Paraiba do Sul River Delta, one of worldwide example of wave dominated deltas. To achieve the objectives we use different frequencies with the antennas with 80, 200 and 400 MHz, with the equipment made by Geophysical Survey System Inc. The results showed that the GPR lines obtained in the Pleistocene Beach ridges describe a observation of sequences of reflectors of foredunes in the top, and beach and upper and lower shoreface in the base of the line, a typical sequence of regressive coastal barrier, formed under conditions of sea level falling. On the other hand the morphology of the Holocene barrier is characterized by transgressive barrier and lagoon spit, even of the regressive pattern of the sea level in the last 5.500 years B.P. In this case the radar facies showed a well preserved sedimentary structures by the continuous overwhash process and lagoon spits, along barrier lagoon system. We conclude that the radar facies showed important indicators about the genesis of these features and the relative sea level.
Ruiz de Alegria-Arzaburu, A., Mariño-Tapia, I., Silva, R., Pedrozo-Acuña A., 2013. Post-nourishment beach scarp morphodynamics
Large and persistent beach scarps can be safety hazards to beach users and result in serious social and economic implications. In this study the morphological evolution of beach scarps of large dimensions is examined on a nourished microtidal Caribbean Mexican beach. Beach profiles were measured three-to-four monthly along the beach after the nourishment in December 2009 and over 1.5 years. A beach scarp was defined as a feature with a slope larger than the critical angle of repose of 32° and a minimum height of 0.25 m. The top and bottom positions of the scarps were calculated from the minimum and maximum values of the second derivative of the measured beach profiles (slope gradient). The cross-shore morphological evolution of the scarps was related to wave runup (R2) and tides, and also to both with the contribution of the longshore energy flux (Pl). During calm conditions characterised by longshore uniform mean and maximum R2 of 0.73 and 0.83 m, and Pl=180KN/s, the scarps remained present along the beach. Energetic conditions with mean and maximum R2 of 0.83 and 1.2 m and Pl=400KN/s, increased the longshore rythmicity of the beach and induced significant cross-shore erosion (over 20 m) and the disappearance of ~50% of the scarps. The added contribution of the longshore energy flux, wave runup and tidal elevation explain 40% of the morphological evolution of beach scarps over the study period.
Silva, T.A., Freitas, M.C., Andrade, C., Taborda, R., Freire, P., Schmidt, S., Antunes, C., 2013. Geomorphological response of the salt-marshes in the Tagus estuary to sea level rise.
Salt-marshes are highly valuable ecosystems due to their role in supporting the aquatic and bird life. Furthermore, many anthropogenic activities such as agriculture, salt production or aquaculture targets these areas. They also act as protective barriers to shores, given their ability to dissipate most of the wave and current energy in high tide. Sea level rise can place these intertidal zones at risk, reinforcing the need to understand their morphosedimentary and dynamic response to the variations on the forcing factors, thus allowing for a better management of these environments. Large expansions of salt-marshes and tidal flats are among the morphodynamic contents of the Tagus estuary. This study focuses on the recent past evolution of Tagus marsh areas in order to understand their geomorphological response to higher sea level scenarios. Cores were taken in four contrasting high salt-marsh expansions in estuarine margins (Trancão – TR, Mouchão da Póvoa – MP, Pancas – PA and Corroios - CO). Marsh surfaces were surveyed using DGPS-RTK and tidal regime characterized at each location. The cores reached at least 1.20m in depth and were sub-sampled every cm for 210Pb and 137Cs radioisotope determination, allowing the derivation of sedimentation rates. In all locations, accretion rates clearly exceed the post-1920 mean rate of sea level rise ( 0.21cm/year, Cascais gauge). Their linear extrapolation into the future, until reaching the upper threshold of marsh surface aggradation (MSHT), suggests that Tagus marginal marshes will not drown under the projected sea level elevation scenarios for the end of the 21th century.
Silveira, T.M., Carapuço, A.M., Sousa, H., Taborda, R., Psuty, N.P., Andrade, C. and Freitas, C., 2013. Optimizing beach topographic field surveys: matching the effort with the objectives
In any study design, the surveying approach should match the objectives, thereby limiting the effort to focus on the purpose of the inquiry. Often, in beach geomorphological research, study design is based on expert judgment, that does not assure the optimization of the field surveys. In this study, several dimensions of survey strategies were evaluated to compare the outcomes and uncertainties associated with field data collection. The objective of this work is to assess the accuracy of the derived volumes achieved by different survey strategies, including cross- and alongshore lines, with varying density and spatial distribution, to optimize the field survey effort. A number of survey strategies are simulated, covering a range of data resolutions and configurations, replicating a number of possibilities for field data gathering. Topographical data from different field surveying approaches were analyzed for a 4 km long coastal stretch in Portugal. Measures of beach volume were computed from cross-shore as well as alongshore information, and the errors associated with each approach evaluated. Results show that beach volume varies with the adopted survey strategy. As an example, beach volume change can be adequately portrayed and survey effort minimized either through the surveying of 3 alongshore lines, or through 200 m spacing beach profiling. This work highlights the importance of the study design in beach contexts because of its inevitable influence on the results of volumetric change analyses.
Thomas, T., Phillips, M. R., and Williams A. T., 2013. A Centurial Record of Beach Rotation.
Beach rotations are reliant on a bi-directional wave climate and headlands to impede alongshore sediment transport. This manifests itself in localised shoreline retreat or advance but does not lead to long term sediment loss or gain, as beaches often return to initial conditions in response to wave direction shifts and these changes are often seasonal. This paper assesses morphological changes of a headland embayed beach (Tenby, West Wales) over a 180 year period using GIS, cross shore profiles, and wave modelling. Within GIS maps, aerial photographs and direct field measurements identified two significant changes in beach orientation between the periods 1830–1919 and 1919–2009. Analysis of more recent data (1941–2009) showed that a statistically significant (R2 = 64%) negative phase relationship existed between the beach extremities and correlation changes revealed central region rotation. Results were consistent with wave modeling (RCPWave) that showed dominant waves emanate from southwest and cause long term longshore drift from south toward north. Subdominant waves emanating from the southeast cause counter-drift. In the decadal and seasonal term, negative phase relationships indicative of beach rotation were also established. Cross-correlation analysis between beach extremities showed that decadal term rotation occurred at timescales of less than one year. This was verified by seasonal term results, which showed with increased statistical significance that sediment exchange between headlands takes up to two months. Results have implications for coastal zone management and careful examination of these phenomena is required over both seasonal and longer timescales and should be considered in the development of new beach management strategies.
Tillmann, T. and Wunderlich, J., 2013. Barrier rollover and spit accretion due to the combined action of storm surge induced washover events and progradation: Insights from ground-penetrating radar surveys and sedimentological data.
Barrier islands and spits are geological young, highly dynamic and represent a complex coastal system that includes a number of different but closely related sedimentary depositional environments. In this study ground-penetrating radar data of different antenna frequencies and sedimentological data were combined to reveal the sedimentary structure and architecture of the southern barrier island spit of Sylt and to set up a barrier island stratigraphy. Based on these data, two sedimentological models have been generated for Southern Sylt which describes the inter-action between extreme events, coastal processes and sedimentary development and contains the major episodes of barrier island evolution. The first model is concerned with the spit add-on zone where the barrier spit is attached to the central island moraine core and shows a landward migration through barrier rollover affected by an interplay of barrier retreat and washover flooding associated with accumulation of sediment in a backbarrier environment as a result of several storm surges. The spit add-on zone reveals a transgressive coarsening upward sequence starting with sandy mud flat deposits at the bottom which turn into coarser sandy tidal flat deposits toward the top. Sandy tidal flat deposits are overlain by washover sheet and washover fan deposits. The second model demonstrates a barrier spit accretion through southerly directed progradation. Eroded sediment was transported along the west coast of Sylt by longshore drift and was added to the southern spit-end. Progradation and barrier spit accretion were interrupted by severe storm surges. Storm surge generated erosion unconformities in a foreshore to shoreface environment redraw old spit-end positions that represent stages of barrier spit progradation.
Vila-Concejo, A. Harris, D.L., Shannon, A.M., Webster, J.M., and, Power, H.E., 2013. Coral reef sediment dynamics: evidence of sand-apron evolution on a daily and decadal scale
This paper investigates sand apron progradation on decadal and daily scales on a platform reef (One Tree Reef, OTR) located in the southern Great Barrier Reef. The decadal scale is addressed by analysing sand apron progradation using remotely sensed images (aerial photos and satellite imagery) coupled with wind data and cyclone events. The daily scale is addressed through a field campaign that was undertaken in September-October 2011. The campaign consisted of hydrodynamic measurements in three stations over the southern sand apron in OTR. It was found that while there was a small overall progradation over the last 31 years, the progradation had not occurred continuously or consistently along the entire sand apron. Additionally, the effect of cyclones was not clear on the decadal scale. On the daily scale, it was found that currents are generally weak (<0.4 m/s) and that currents during conditions at which suspended sediment is maximized are ocean-ward directed on the central part of the sand apron and lagoon-ward directed on the easternmost end. As such, daily sediment transport does not represent a gross contribution to lagoon infilling by sand apron progradation. Our results show that sand apron progradation does not occur continuously on the decadal or the daily scale.
Vilumaa, K., Tõnisson, H., Kont, A. and Ratas, U., 2013 Ground-penetrating radar studies along the coast of Estonia.
Ground-penetrating radar (GPR) profiling has been performed in the study sites in west Estonian archipelago (Röögu, Lõimastu) and on the northern coast of the mainland (Juminda). The west Estonian study sites have emerged during regressive phases of the Limnea Sea. The coastal landforms there are younger and smaller than the landforms in northern Estonia, which have emerged at the beginning of the Ancylus Lake stage of the Baltic Sea. The study sites are characterized by a series of beach ridges, which are parallel to the shoreline. These ridges are separated by narrow and wet depressions where non-calcareous sand is covered with peat. The beach ridges are located at different distance from the current shore and at different altitudes. The results are based on cartographic analysis, topographic survey and georadar (SIR-3000, 100 MHz frequency) survey along transects. About 1 km long GPR profiles perpendicular to the ridges were examined. The GPR data were calibrated and compared with peat coring data. The average electromagnetic wave (EMW) speed values were: 0.035 m/ns for peat and 0.05 m/ns for sand. The study was conducted in order to determine the thickness of peat (0.2–2.0 m) and to characterize the topography of sub-peat mineral surface. Two different patterns of bedding in the sand layer can be detected. The top layers (1–1.5 m), which are probably of aeolian origin, are almost parallel to the surface of the initial beach ridges. Most of the lower layers are tilted seaward. Those layers may indicate a cross-shore transport of sand by waves.
Yuhi, M., Dang, M.H., Umeda, S., 2013. Comparison of accelerated erosion in riverbed and downstream coast by EOF analysis.
This study investigates the long-term variations of sediment volume in an integrated watershed composed of the Tedori River and the Ishikawa Coast, Japan, where both the riverbed and the coast have experienced rapid and serious erosion due to the combined effects of natural and anthropogenic factors. Contemporary data for coastal and riverbed evolution were compiled and compared, and the decadal variations of the seabed and riverbed elevation were examined using a set of field surveys collected over several decades. These topographic data have been analyzed using empirical orthogonal functions (EOFs) to determine the coastal responses to the reduction of sediment supply related to the antecedent riverbed erosion. It was shown that the characteristics of volumetric variation could be captured well by the temporal coefficient of the first mode of EOFs. The study area was divided into several sub-regions, and the variations of sediment volume were examined on decadal scales. The correlation between the variations has been discussed in relation to the anthropogenic modification such as the material mining in the river basin and the construction of coastal structures. On the regional scale, the correlation between the river and coastal evolution showed that the anthropogenic modifications in the fluvial basin have led to an accelerated imbalance of the coastal sediment budget, while the modified river regulations and construction of coastal structures have recently mitigated the river and coastal erosion. Several years of time lag were recognized between the riverbed and the coastal erosion.
Zhang C. K., Yang Y. Z., Tao, J. F., Chen, Y. P., Yao, P., Su. M., 2013. Suspended sediment fluxes in the radial sand ridge field of South Yellow Sea.
The radial sand ridge at the South Yellow Sea is one of unique geomorphic units in the world. It is famous of its radial current pattern and high suspended sediment concentration, forming abundant tidal flat resources which could be reclaimed for the land use. In order to make a scientific plan for the land reclamation, it is necessary to quantitatively understand the distribution of suspended sediment fluxes in this field. In this study, a 2D tidal current and suspended sediment transport model is developed and validated by the hydrologic survey data measured in 2006. The suspended sediment fluxes are calculated by the period-averaged multification of the simulated tidal current and sediment concentration in two consecutive tidal periods. The numerical results show that, in either winter or summer season, there has a positive sediment flux comes from the north and the south boundaries, indicating a net gain of sediment for the sand ridge field from both boundaries. The numerical results also show that a clockwise sediment flux system exists in the middle of the sand ridge field, but a small portion of sediment leaves the sand ridge area at the north wing. The overall gain of the sediment in this field is positive, implying that the radial sand ridge is still in the growing process.
Zhang, C., Zheng, J.H., Dong, X.W., Cao, K. and Zhang, J.S., 2013. Morphodynamic response of Xiaomiaohong tidal channel to a coastal reclamation project in Jiangsu Coast, China.
Xiaomiaohong tidal channel is located at the southern part of the large-scale radial sand ridge system along Jiangsu Coast, China. A land reclamation project was carried out on the tidal flat at the south bank of Xiaomiaohong channel in 2003, which led to the considerable change of channel morphology. This study aims to investigate the morphodynamic response of the tidal channel to the reclamation project through field observation and numerical modeling. Measured data shows that bed deposition occurred at both the east and west sides of the project area while erosion is found between the project area and the channel axis, especially around the northwest corner of the project area. The relationship between the observed bathymetry change and the reclamation project is discussed. A two-dimensional numerical model is developed to investigate the project effects on the tidal current, tidal volume, sediment concentration and morphological evolution. It is indicated that the change of morphodynamic processes due to the reclamation project is only concentrated near the project area and the project does not significantly influence the overall channel evolution. While the nearby current direction and velocity were changed and the tidal volume was reduced after the reclamation, sediment concentration was little affected. The model is able to qualitatively simulate some important evolution trend of the channel under the impact of reclamation project but some difference is also found with respect to the erosion/deposition intensity and scale.
Almeida, L.P., Masselink, G., Russell, P.E., Davidson, M.A., Poate, T.G., McCall, R.T., Blenkinsopp, C.E. and Turner, I.L. 2013. Observations of the swash zone on a gravel beach during a storm using a laser-scanner
The collection of detailed field measurements from the swash zone during storms is an extremely challenging task which is difficult to execute with traditional in-situ deployments (e.g., scaffold rigs with instruments). The levels of difficulty increase for gravel beaches where the wave energy reaches the beach face with almost no loss of energy, leading to violent plunging wave breaking on the beach face that can produce large vertical morphological changes and extremely strong uprushes that can easily and rapidly damage, bury or detach instrumentation. Remote-sensing techniques emerge as the most appropriate solution to perform field measurements under such adverse conditions since they have the ability to perform measurements without being deployed in-situ. A mid-range (~ 50 m) Laser-scanner mounted on a tower (~ 7 m high) in the mid beach face of a gravel beach (Loe Bar - SW England) was used to measure bed-level changes and runup at a sampling rate of 2 Hz along one beach profile during a storm. The results from the comparison of this system with other state-of-the-art instruments (e.g., ultrasonic bed level sensors, GPS and video cameras) indicate that the quality of the measurements obtained is within the accuracy of the standard methods. The advantages of this system is the reduced logistical infrastructure required for the deployment, the capability to perform surveys with high spatial and vertical resolution, during day and night, and to reach areas of the swash zone where no other instrument can be deployed safely. Measurements performed with a laser-scanner on a gravel beach (Loe Bar) show complex and fast-changing morphology on the gravel beach, which appears to be a form of negative morphodynamic feedback to controls the hydrodynamic evolution in the swash zone.
Araújo, M.A.V.C., Mazzolari, A. and Trigo-Teixeira, A., 2013. An object oriented mesh generator: application to flooding in the Douro estuary.
This paper presents the modification and improvement of an existing 2D unstructured finite element mesh generator, based on the advancing front concept. The original version of this mesh generator (MESHGR) was developed in Fortran language and, in this study, it is ported to C and improved in terms of robustness, efficiency and speed. The C code is object oriented and uses classes to describe each object. Besides generating the mesh, the code also enables some post-processing operations: mesh smoothing, edge swap and edge collapse algorithms are implemented based on triangle quality criteria. A R-tree algorithm is used to speed up interpolation and increase robustness. Various mesh generation strategies for the finite element analysis of shallow water flow are presented. The mesh generation is based on a series of criteria or size functions defining the mesh node density, which take into account the hydrodynamic, physical and geometrical features of the domain, such as the bathymetry and topographical length scales. The implemented algorithms create efficient automated unstructured meshes in which the triangular elements do not require further manual processing. The methodology is tested in a real complex domain, in the simulation of an extreme flood event in the Douro estuary, using the ADCIRC shallow water model, and proves to be successful. Computed results are in agreement with the historical records of water level for this estuary.
Ba, A. and Sénéchal, N. Extreme winter storm versus summer storm: morphological impact on a sandy beach
This contribution presents the morphologic response of a double-barred sandy beach facing the Atlantic swells in the south west of France under two storm events: the first one occurring during summer period while the beach is experiencing seasonal accretive conditions and the second one during winter while the beach is experiencing seasonal erosion conditions. Shoreline positions, inner bar positions and beach states were extracted from rectified merged video data. Despite a significant difference in usually considered storms thresholds (Hs, duration), the winter storm (Joaquim) being associated to Hs up to 8.5 m during 120 hours and the summer storm being associated to Hs up to 4.5 m during 17 hours, the shoreline and the inner bar positions one week after the apex of each storm were very similar to the one observed previous the apex. Analysis of wave conditions preceding the two events indicates that, relative to them, the two storms were similar in energy but also that conditions observed during falling conditions were favourable to rapid recovery. The beach morphology was probably also close to its equilibrium shape prior to each storm, and this may have vanished severe beach morphology readjustment. Indeed, computed averaged Gourlay parameters are consistent with observed beach states while sync-storm Gourlay parameters are not necessarily. Data also suggest that tide together with the storm duration may explain why no up-state transitions was observed during the summer storm while an slight up-state transition was observed during the winter storm. Thus our data suggest that recovery period can be very rapid even under extreme storms.
Bae, J.S., Yoon, S.B., Choi, J., 2013. Boussinesq Modelling of a Rip Current at Haeundae Beach.
The rip current occurring at Haeundae beach in Busan, South Korea was numerically investigated under directional random wave environment. The numerical simulations were performed using a fully nonlinear Boussinesq equation model, FUNWAVE which is capable of resolving phase interaction and simulating nearshore circulation since it includes the effect of wave-induced momentum flux and horizontal turbulent mixing. To examine the modelling, the rip current occurred on the 12th of June, 2011 at Haeundae beach was simulated by using observations. The results of numerical simulation showed the time-dependent evolution of the wave-induced nearshore circulation that was caused by transformation of random waves due to the unique topography of Haeundae beach. And, it was found that the rip current was well generated and developed through the region where relatively lower wave heights were caused by refraction and diffraction of waves due to the topographical characteristics (i.e., submerged shoal). In addition, we found that a narrow-banded spectral wave (i.e., a swell spectrum) close to a regular wave generates stronger rip current than a broad-banded spectral wave under an equivalent wave height and period condition.
Benavente, J., Del Río, L. Plomaritis, T.A, Menapace, W. 2013. Impact of coastal storm in a sandy barrier (Sancti Petri, Spain).
Behaviour of sandy geomorphological units under the impact of coastal storms is of great importance when studying coastal evolution in a medium- to short-term scale. In this paper we analyze the effect of storms in determining the recent evolution of Camposoto beach, a sector of Sancti Petri sandspit (Cadiz, SW Spain). Morphological and volumetric changes of washover deposits were evaluated under the effect of coastal storm series recorded during the winter 2009–2010. Several pre- and post-storm topographic surveys of the beach and foredune were performed using an RTK-DGPS, together with a topographic survey of the dune system and the washovers after that winter. The results were compared with dating from the winter 2008–2009, and with a DTM extracted from LIDAR from 2008. Moreover, changes in the area covered by the washover deposits and in the foredune morphology were evaluated by means of GIS tools on aerial photographs from 2008 and 2010. Results showed clear shoreline retreat in the study area, as well as an important impact of the 2009–2010 storm seasons over the foredunes. Changes in the morphology and dimensions of the washovers gave information about the patterns of storm-related medium-term evolution of the system. The above data were used for the calculation of thresholds of the minimum wave height capable of either activating former washover deposits or creating new washovers and foredune retreat. Based on these results we established thresholds for storms generating coastal retreat in the long-term evolution of the sandspit, as a consequence of dune erosion and overwash processes.
Bugajny, N., Furmańczyk, K., Dudzińska-Nowak, J., Paplińska-Swerpel, B., 2013. Modelling morphological changes of beach and dune induced by storm on the Southern Baltic coast using XBeach (case study: Dziwnow Spit)
The purpose of this paper is to demonstrate the usefulness of XBeach model (1D) in modelling changes of beach and dune morphology in terms of significant storm influence at sandy Dziwnow Spit area located in the non-tidal Baltic Sea, on the western part of the Polish coast. Research were carried out in the framework of the MICORE project (7th FP) the main goal of which was to develop an operational early warning system for coastal hazard based on the XBeach model. For model calibration, one significant storm event registered in 2009 was simulated and compared against pre- and post-storm morphological data consisting of geodetic measurement and airborne laser scanning data. XBeach model has been run for 8 cross-shore profiles with different configuration of model parameters. The model skill were tested on the base of statistical descriptor BSS for the terrestrial part of the profiles. The highest BSS values varied from 0.54 to 0.90 depending on the profile. The best performance of XBeach model for each profile was obtained by deactivating longwave stirring lws and keeping hmin parameter value to 0.05 in all simulations. Values of wetslp equalled 0.3 or 0.4 while dryslp were 1 or 1.5. The facua parameter values oscillated between 0.1 and 0.5. The results show that XBeach is reasonably modelling morphological changes like dune and beach erosion induced by storm event in Southern Baltic conditions and can be successfully applied to create an effective tool for hazard prediction.
Cho, K.-H., Choi, J.-Y., Park, K.-S., Hyun, S.-K., Oh, Y. and Park, J.-Y., 2013. A synoptic study on tsunami-like sea level oscillations along the west coast of Korea using an unstructured-grid ocean model.
Abnormal tsunami-like sea level oscillations were recorded along the west coast of Korea on March 29–31, 2007, and May 4, 2008. These oscillations had maximum amplitudes of 1.6 m and 1.4 m, respectively. Analysis of observation data revealed that sea level oscillations coincided with atmospheric pressure disturbances moving eastward over the Yellow Sea. The atmospheric pressure disturbance in 2007 was characterized by a 5.3 hPa air pressure jump at Yeonggwang whereas that in 2008 was characterized by a 2–3 hPa change at Boryeong. To understand the generation and amplification mechanisms of the two events, we carried out synoptic numerical experiments using a two-dimensional unstructured-grid ocean model. From analyses of weather radar images and weather charts, we estimated the direction and speed of the atmospheric pressure jump over the Yellow Sea. Atmospheric pressure disturbances during the 2007 and 2008 events moved with average speeds of 24 m·s−1 and 28 m·s−1, respectively, which are nearly equal to the propagation speed of the long ocean wave. As this movement occurred, it appears that sea level oscillations were enhanced via Proudman resonance over the Yellow Sea. Numerical simulations reproduced, reasonably well, the occurrence time and amplitude of sea level oscillations during 2008 event. However, simulations were unable to reproduce adequately the oscillation peaks during the 2007 event because they failed to reach near-resonant conditions over spatially varying water depths. For the synoptic experiments, we designed four types of atmospheric pressure jumps, each having a different size as defined by differences in amplitude, width, and length. In a variety of synoptic experiments, the gradient of atmospheric disturbance plays a significant role in amplifying long ocean waves under a near-resonant condition. The effects of a complicated bathymetry and geometry on long wave amplification still remain to be studied, including those of shoaling and local eigenfrequencies.
Chun, J., Ahn, K., Yoon, J.-T., Suh, K.-D. and Kim, M., 2013. Projection of extreme typhoon wave : Case study at Busan, Korea
Several studies predicted that the typhoons will be more intense in the future. Since the intensification makes the wave environments at the coastal zone more extreme, the analysis on the enhancement of typhoon waves is required for the future protection of the coastal zone. Most of the extreme wave analysis is based on the measured or hindcast wave data which does not reflect the future trend of variations. This study discuss the add-on effect of future typhoon intensification on the estimation of extreme waves. Especially, since the extreme waves at Busan port, Korea are generated by typhoons, the trends of the activity and intensity of typhoons on the southern coasts of Korean Peninsula between 1951 and 2010 were analyzed. At the analysis, it was found that there is a trend in the intensity of typhoons. By applying the wavelet analysis, the long-term trend of the intensity of typhoons on the southern coasts of Korean Peninsula was obtained. The increasing rate of annual maximum pressure drop is 0.0786 hPa/yr. After 50 years, the pressure drop and maximum wind speeds will increase by 3.93 hPa and 2.5 m/s, assuming that this trend will be maintained in the future. Applying these values to six historic intense typhoons, the changes of wave heights by these typhoons were calculated. According to the present numerical simulations, the significant wave heights will increase by 1.24 m after 50 years.
Collin, A., Etienne, S. and Planes, S., 2013. High-energy events, coastal boulder deposits and the use of very high resolution remote sensing.
In recent years, coastal boulders have become a trendy proxy in studying high-energy marine inundation events. From their morphology and spatial distribution, authors are able to characterize a singular event in terms of intensity (wave height, flow velocity). Recent post-catastroph studies (e.g. Indian Ocean 2004 and Japan 2011 tsunamis) have demonstrated also the interest of boulder deposits in reconstructing the event kinematics through a multi-proxy approach. But as boulder studies require a statistically robust dataset they are field-time consuming and sometimes fieldwork takes place in remote areas with low facilities. The use of very high resolution remote sensing could overcome some of these limits. In this paper, we evaluate the possibility to identify meter-size coral boulder thrown on a reef flat during the hit of a tropical cyclone. Image analysis allows for the discrimination of major geographical object encountered on coralline islands: submerged coral boulder, emerged coral boulder, perched reef, sand beach. Within emerged boulder population, specific bands available with WorldView-2 images (i.e. red and NIR2 band) allow the spectral discrimination and mapping of fresh and weathered elements.
Cooper, J.A. G. Jackson, D.W.T. and Gore, S. 2013. A groundswell event on the coast of the British Virgin Islands: spatial variability in morphological impact.
Extreme waves on Caribbean islands originate from hurricanes, tsunami and swell. The latter are most widespread and common but are the least studied. They are generated by slow-moving, low pressure systems in the western Atlantic from which swell propagates in all directions, some of it reaching the exposed shores of Caribbean Islands. Large swell waves with an approximate 1:20 year return interval reached 14–16 ft (>4.5 m) waves with a 17 second period during March 2008. Morphological impacts (coral reef damage, coral rubble deposition, beach erosion) were reported throughout the Eastern Caribbean from Guyana to Puerto Rico. In this paper we present observations of morphological impacts on sand, gravel and coral rubble beaches of the British Virgin Islands (BVI). The morphological response was highly variable according to coastal geologic setting, exposure to wave activity and nature of beach material. Exposed sand beaches with sandy shorefaces exhibited scarping, overwash and offshore sand transport, similar to that reported elsewhere for sand beaches. In some instances covering sand was stripped to expose underlying beachrock. Sand beaches with fronting reefs showed little change. Modification of coarse clastic beaches through erosion and deposition generally amounted to little more than surface modification of much larger hurricane and tsunami deposits.
Dewez, T.J.B., Rohmer, J., Regard, V., and Cnudde, C., 2013, Probabilistic coastal cliff collapse hazard from repeated terrestrial laser surveys: case study from Mesnil Val (Normandy, northern France)
Along cliff edges, coastal managers dealing with life-safety matters often wonder “how much time have I got left before I need to expropriate this house?” Here, we present a case study where repeated terrestrial laser scanner surveys (TLS) were performed to monitor a chalk cliff section in Normandy. The Mesnil Val cliff, cut in Upper Cretaceous chalk known as the Upper Lewes Nodular Chalk, is a ca. 750-m-long, 20–80m-high cliff section. It was surveyed 6 times between December 2005 and March 2008 at a 1 –point-per-5cm resolution. Successive Digital Surface Models (DSM) of the cliff surface were subtracted to reveal the location and shape of erosion scars. Scars detection relies on a robust indicator of observed noise distribution. The resulting scar inventory contains more than 8500 objects with volumes spanning 8 orders of magnitude (10−4 to 104) cubic meters. Probability Distribution Functions (PDF) of erosion scar thickness, area and volume scale as power laws. The scaling relationships between area (0.77) and volume (0.53) power law exponents demonstrate that rockfall are simply scaled (area/volume exponent ratio = 3/2). This finding legitimates the inference of rockfall volume distribution from easy-to-measure area PDF. PDF can also be turned into complementary cumulative distribution function (CCDF) which then gives the annual rate of exceeding a given scar dimension. Our statistical estimates have been empirically validated with five complete cliff collapse events occurring on the same cliff section in 13 years. Repeated TLS surveys provide invaluable information to help coastal managers make informed decision.
Finkl, C.W. and Makowski, C., 2013. Perception of Coastal Hazards in Terms of Physical, Biological, and Human-Induced Cascades: An Example from the Southeast Florida Coastal Zone (SFCZ).
Discussions of coastal hazard impacts commonly emphasize geomorphological, geodynamic, and meteohydrodynamic physical events. A true census of all coastal hazards must also, however, include not-so-obvious biological and anthropogenic impacts. Biological coastal hazards are now more common because increasing human presence along shores fosters contact with hazardous biological flora and fauna. Human-induced hazards, often viewed as normal daily activities, cryptically lead to unwanted erosion and deposition or to the pollution of coastal marine environments. The South Florida Coastal Zone (SFCZ) is a good example of how all three categories of coastal hazards (physical processes, biological ecodynamics, and anthropogenic machinations) collectively constitute a negative-pressure cascade upon the coast. Accurate identification and assessment of coastal hazard cascades is the critical ‘first step' in forming effective disaster resilience through public awareness.
Freitas, J.G., and Dias, J.A., 2013. 1941 windstorm effects on the Portuguese Coast. What lessons for the future?
On February 15, 1941, the Iberian Peninsula was struck by a devastating windstorm. Human and material losses were significant. Coastal areas were among the most affected. Storm surge caused by strong wind and low atmospheric pressures favoured overwash occurrence. Unlike other past catastrophic events, there is abundant information on the 1941 windstorm. Historical sources – newspapers, survivor's testimonies and official institutions reports - allowed us to realize its impact on territory and on populations. Until today 1941 phenomenon is still the biggest known storm. However, what happened then is almost forgotten. But, it can happen again. Sesimbra and Ria Formosa coastal areas are excellent case studies to understand what happened on the windstorm day and to discuss what could happen if an event like this reaches those regions again. The analysed data lead to the conclusion that the consequences would be even more devastating. First, because the current urbanization level is much higher. Second, Sesimbra and Ria Formosa are as vulnerable (or even more) to extreme events as they were in 1941. Third, its inhabitants have no “risk memory” and therefore have no concept of the danger inherent to seashore occupation. Preserving the memory of such events can be a way of preparing people for new disasters and to get authorities to take concrete measures to mitigate their effects.
Heo, K.-Y., Shim, J.-S., Kwon, J.-I., Jeong, J.-Y., Park, K.-S. and Choi, J.-W., 2013. Abnormal storm waves around the Korean Peninsula: A case study of an extratropical explosive cyclone over East Sea.
On April 3, 2012, an extratropical explosive cyclone developed over East Sea, producing heavy rainfall and strong winds. This cyclone produced maximum wind speeds of up to around 21 m s−1 over the ocean around Korea. As the explosive cyclone developed rapidly from 00 UTC April 3, 2012, it began to affect the coastal areas, and abnormal storm waves were generated by the strong wind. The observed maximum wave heights and periods around Korea were 11.1 m and 9.1 s at Chilbaldo, 12.0 m and 9.1 s at Marado, and 13.7 m, and 5.8 s at Ulleungdo in the period 04–10 UTC April 3, 2012. The objectives of this study are to investigate the mechanisms and conditions favorable for the development of the explosive cyclone, and to investigate the influence of the cyclone on the abnormal storm waves. To achieve the above objectives, numerical studies are conducted using the Weather Research and Forecasting (WRF) model as an atmospheric model and the open ocean wave model WAM. The explosive cyclone is amplified by latent heat release as well as the formation of an upper-level cut-off low, which resulted in the rapid intensification of the cyclone; while surface heat fluxes had a lesser contribution to the explosion of the cyclone. In situ meteorological observation data and wave data from buoy measurements for this event are available for comparison and validation. The comparisons show that the WRF and WAM models can accurately predict the wind speed and wave height.
At Haeundae Beach in Busan, which is located in the south-east part of South Korea, rip currents have recently occurred many times, and more than 100 people were swept away by fast-moving seaward currents in 2012. The main objective of the present study is to provide preventative measures for the protection of human life in areas where rip currents occur. The Korean Meteorological Administration plans to set up monitoring systems to establish the forecasting of rip current generation for the sake of public safety at Haeundae beach. To provide a user-friendly simulation tool, a forecasting system has been built in the form of a software package called HAECUM. The coastal flows and waves are produced at each time step and grid point by means of the systematic interfacing of hydrodynamic and wave models in HAECUM. The outputs from the system are viewed as combined current vectors for the ease of decision-making by emergency management officials. Using Lee's approach for estimating the surface onshore currents due to wave breaking, we compared measured data from real rip currents in the summer season of 2012 with the results from the model calculated with incident wave conditions, and rip current forecasting model for Haeundae beach is verified.
Kim, M.S. and Woo, S.B., Eom, H.M., 2013. Propagation of abnormal wave on 25 April 2008 at the West Coast of South Korea
On 31 March 2007, abnormal waves suddenly hit the West Coast of South Korea, causing heavy casualties and huge economic loss. Since the cause of wave generation is unknown, we aim to study the direction of wave propagation by investigating the abnormal wave signal recorded in the tidal stations. To determine the propagation direction of abnormal waves, we analyzed tidal level observation data at 1-min intervals, provided by the Korea Hydrographic and Oceanographic Administration (KHOA). To remove tidal components, wavelet decomposition, which filters wave periods ranging from 2 to 60 min, was performed. If the daily maximum amplitude exceeding 95% confidence interval of the total daily maximum amplitudes appeared simultaneously at more than three tidal stations, the day was defined as the day when abnormal waves occurred. Because of nonstationarity and localized peak in the time domain, wavelet analysis can be suitable for analyzing the power spectrum and wave period of abnormal waves. The time when maximum total power spectrum of the decomposed time series appears for the first time is considered the arrival time of the abnormal wave. The distance of crest line propagated by the abnormal wave was calculated by considering the arrival time difference between stations and long wave speed. The abnormal wave is assumed to propagate along a tangent to a circle with radius equal to the distance which the abnormal waves moved. Based on these considerations, we found that the propagation direction of the abnormal waves on 31 March 2007 was from the northwestern corner of the West Sea to the West Coast of South Korea. Similarly, abnormal waves that occurred on 25 April 2008 were propagated from the northwestern corner of the West Sea to the east–southeast.
Kim, T.R., Kang, T.S., Chun, J. and Hong, S.J., 2013. Development of system to countermeasure large swells on the East coast of Korea.
A recent increase in damages from large swells hitting the east coast of Korea has necessitated a system warning people on the shore. This paper introduces the development of a large swell warning system in the east coast of Korea using a wave numerical model in unstructured grids with offshore wave measurement data at the boundary as input conditions. Rapid warning and easy operation by nonprofessional operators in local government on the coast were important considerations. The system built a scenario DB of all the cases of swell hits to the coast, in terms of time and location, related to their detection at an offshore wave measurement site. Once the swell propagation field DB is constructed, whenever a dangerous swell is detected at the offshore site, the time and location for the dangerous shore hit by this swell is immediately picked from the DB and can be used for warning people by blocking the approach to the shore, siren, broadcasting or APP service in the smartphone.
Lee, G., Kim, J. and Jun, K.S., 2013. Estimation of probable flood discharge in tidal river using unsteady flow model
A method for estimating the probable flood discharge using unsteady flow model was developed. The method consists of two steps. Firstly, the unsteady flow model is applied to the current stream condition to simulate the peak discharge for each historical flood event. Then, the probable flood discharge is calculated by conducting a frequency analysis on the annual maximum series or partial time series of simulated peak discharges. The proposed method avoids the estimation of the probable rainfall and application of a rainfall-runoff model, and the accompanying uncertainty can thus be eliminated. The proposed method was applied to the main stream reach of the Han River in South Korea. The downstream reach of the Han River is greatly influenced by strong tidal variations, and it has another unique feature in that it contains two submerged weirs—Jamsil and Singok. The unsteady flow model was developed by modifying the existing FLDWAV model so as to model the characteristics of the Han River in the context of computational river hydraulics. Historical flood events were simulated and the probable flood discharges along the river reach was computed through partial duration series frequency analysis.
Lee, H.S., 2013. Abnormal storm waves in the East Sea (Japan Sea) in April 2012
The winter East Sea, a semi-enclosed sea surrounded by Korea in the west, Japan in the east and south and Russia in the north, normally experiences rough sea conditions due to East Asian monsoon and winter storms. In April 2012, record-breaking abnormally high waves, significant wave heights of 11.21 m and 12.39 m and significant wave periods of 13.6 sec and 14.3 sec at Akita and Yamagata GPS buoy sites, respectively, were observed along the Tohoku coast in the East Sea side of Japan. It was due to a well- and fast-developed low pressure passing through the East Sea. This paper describes how a low pressure could be grown so rapidly to tropical cyclone level in this time and numerical hindcast results for future forecast and engineering purpose. With respect to the meteorological condition, it is found that strong convective motion due to latent heat and water vapor from Tsushima Warm Current together with an accompanied front increases a pressure gradient at tropopause level accelerating the low growth. In the hindcast using an atmosphere-wave modeling system, two different initial and boundary condition data, NCEP FNL and JMA GSM, are used for applicability test. The result with NCEP FNL data shows a better agreement with observations in terms of surface winds. The observed peaks of significant wave height and period by Akita and Yamagata GPS buoy are captured well in both results. It is also found that the vertical resolution of initial and boundary condition data is important in atmospheric modeling; the higher vertical resolution tends to produce a deeper storm with lower central pressure and strong convective motion.
Haeundae beach draws one million visitors every summer season, and more than 100 people are rescued from rip currents every year. Beachgoers are unexpectedly carried away seawards, as far as 50 ~ 100 meters from shore, where swimming is restricted for safety reasons. Rescuers have strengthened lookout measures at several spots where dangerous rip currents have occurred. The determination of a predictive index for rip currents is vitally important for the protection of human life. Such an index allows governmental agencies to issue rip current warnings directly to the public, and allows for the establishment of preventative measures according to the magnitude of the rip current threat. We apply a modified rip current predictive index suitable for Haeundae - using wave height, wave period, and incident wave angle from the north. Compared with wave data acquired for the summer of 2011, the result of NERiPS-H (NEarshore Rip current Predictive System at Haeundae) index is reasonable and appropriate. Unfortunately, we have insufficient observed wave data. So, our NERIPS-H method has insufficient reliability. This lack of wave data will be addressed by additional intensive field surveys. Additional intensive field experiments were carried out at Haeundae Beach from June to August, 2012 for the collection of data. This in-situ measurement data will be used to improve the reliability of rip current predictive guidance.
Li, F., van Gelder, P.H.A.J.M., Callaghan, D.P., Jongejan, R.B., den Hijer, C. and Ranasinghe, R., 2013. Probabilistic modelling of wave climate and predicting dune erosion considering sea level rise
Knowledge about future oceanographic events will assist governments to better manage risk in coastal zones, a crucial task in the light of projected sea level rise, population growth and economic development. In this study, a 31-year data set of deep water wave climate parameters and bathymetry measurements (yearly cross-shore transect surveys) at Noordwijk, the Netherlands, were analyzed (1) to jointly estimate storm events variates of deep water wave conditions, and (2) to probabilistically compute dune erosion volume and the resulting coastal retreat distance with the simulated wave climate and plausible local sea level rise scenarios by 2100. The probabilistic coastline retreat models were applied and adjusted to the study site. Based on the outcomes of this application, a modeling technique can be established to propose a framework for probabilistically describing the coastal risk along the Dutch coast.
Lopes, C., Azevedo, A., Dias, J.M., 2013. Flooding assessment under sea level rise scenarios: Ria de Aveiro case study
Sea level rise is an important consequence of climate change with a significant impact on society and ecosystems. The present work aims to assess the sensitivity of Ria de Aveiro marginal flooded area to the sea level rise. A previous version of the hydrodynamic model ELCIRC was improved extending its numerical grid through the inclusion of the intertidal areas and the marginal topography. The present configuration was calibrated comparing model predictions with sea surface elevation data recorded at ten stations distributed throughout the lagoon. The root mean square error and the SKILL were computed, and generally an excellent/good agreement between predicted and observed sea surface elevation data was found. Once calibrated, the model was used to simulate the lagoon flooded area under present mean sea level and under two local sea level rise scenarios (0.42 m and 0.64 m), considering mean and spring tide conditions. In average was found an increase of 22% and 35% of the lagoon flooded area, respectively, relatively to the present. Additionally, an increase of 15% and 23% was found for the tidal prism at the inlet, for sea level rise scenarios of 0.42 m and 0.64 m, respectively. Numerical results evidenced that sea level oscillations induce important changes in the lagoon flooded area as well as on the local hydrodynamics. Consequently some activities developed in the lagoon margins may be in jeopardy, i.e. the agricultural fields located at the margins of S.Jacinto channel will be inundated by saltwater, if these sea level rise projections are confirmed.
Mano, A., IIda, T., Udo, K., and Tanaka. H., 2013. Breaking process and mechanism of coastal levees on Sendai Bay Coast hit by 2011 mega tsunami
The 2011 mega tsunami induced by the East Japan Earthquake, Mw 9.0 hit the Sendai Bay Coast, overtopped the coastal levees and intruded deeply onto the Sendai and Ishinomaki plains by flushing people, houses, trees, etc. The levees with 6 to 7 m height had been constructed along 65 km-long sandy beach to protect the hinterland from the storm surges and wind waves. Eighty percent of the levees were broken by the tsunami in various degrees ranging from scatter of the surface blocks to the complete disappearance. The government decided to rebuild the levees with the target of the local major hazards as the storm surges but in a durable way even for the tsunami overtopping. Based on this background, this study aims to find the breaking process and mechanism of the coastal levees especially for the destructive cases. We conducted field survey, and collected aerial photos, tsunami records and videos, blue prints of the levees, etc. We integrated information of the tsunami records and videos, and matched the spatial information of the various data by GIS. These analyses enabled well understanding on the breaking process and mechanisms composed from two steps: (1) The impact of the leading bore with the maximum amplitude of 6 to 7m broke weaker parts like structural joints, parapets, landward soil slopes. (2) Return flow concentration to the broken parts in the first step or to the channels and swamps expanded erosion to make tsunami channels and bays and to lead levee breach.
Matias, A., Masselink, G., Kroon, A., Blenkinsopp, C., and Turner, I.L., 2013. Overwash experiment on a sandy barrier
This paper uses results obtained from the large-scale BARDEX II experiment undertaken in the Delta flume to investigate the morphological response of a prototype sandy barrier to wave and tidal forcing during overwash conditions. Since overwash processes are known to control short-term barrier dynamics and long-term barrier migration, the development of a robust quantitative method to define the critical conditions leading to barrier overwash is important both for scientific and practical management purposes. The Overwash Potential (OP), defined as the difference between the wave runup and the barrier elevation is used to define the overwash threshold condition, and to predict the morphological outcome of a particular overwash event. When OP is negative, wave runup is lower than the barrier crest and insignificant morphological changes are noticed at the barrier crest. When OP is positive, overwash occurs because predicted runup elevation is higher than the barrier crest. When OP is close to zero, overtop is expected with limited intrusion of water across the top of the barrier crest. To make effective use of OP it is necessary to identify a reliable runup predictor. Twelve runup equations were tested for this purpose, and the results were compared with the ones obtained using data from BARDEX experiment on a gravel barrier. A most reliable approach for the determination of OP for sandy barrier was similar to gravel barrier overwash experiments, with runup predictions provided by the equation of Stockdon et al. [Stockdon, H.F., Holman, R.A., Howd, P.A.,Sallenger, A.H., 2006. Empirical parameterization of setup, swash, and runup. Coast. Eng., 53, 573–588]. This is striking, since different runup predictors would have been expected because beach slope, hydraulic conductivity, grain-size, amongst other factors, differ for both types of barriers. Nevertheless, the two main morphologic characteristics for the computation of OP are beach slope and the barrier crest elevation, both accounted for in the proposed equation. The use of OP values provides a practical means by which to identify potential coastal hazards associated with barrier overwash processes and is considered to have a range of practical coastal management applications.
McCarroll, R.J., Brander, R.W., MacMahan, J.H., Turner, I.L., Reniers, A.J.H.M., Brown, J.A. and Bradstreet, A., 2013. Assessing the effectiveness of rip current swimmer escape strategies, Shelly Beach, NSW, Australia .
Rip flow dynamics have important implications for swimmer escape strategies, with recent field studies indicating flow is often contained within the surf zone, re-circulating onto shallow bars. Combining physical measurements in a variety of conditions with various escape strategies allows insights into the safest response by individuals caught in a rip. A three day experiment was conducted at Shelly Beach, NSW in December, 2011. Lagrangian measurements of rip flow using GPS drifters were obtained. Participants with attached GPS were deployed in groups of 3 to 5 in rip currents to simulate various escape actions such as floating with the rip current, and swimming in a parallel direction at varying distances from shore. Day 1 and 2 measurements captured an open beach rip current and an adjacent topographic rip current in moderate energy conditions. Day 3 measurements were obtained on an open beach rip current at a more exposed section of the beach under higher energy conditions. Results were analysed by duration and assessed as being either (i) positive outcome (high chance of safe exit); or (ii) negative outcome (greater potential for hazard). Mean durations were Float (4 min), and Swim (2 min). Of the eight escape scenarios tested, half had potential negative outcomes, including 2 of 3 Float options and 2 of 5 Swim options. Negative outcomes for Floats were related to surf zone exits, and multiple circulations. Negative outcomes for Swims related to swimming against longshore directed circulation. Neither strategy was clearly more likely to result in a successful outcome across all scenarios. Further investigations are currently being conducted in a greater range of hydrodynamic and morphological conditions.
Mendoza, E.T., Trejo-Rangel., M. A., Salles, P., Appendini, C.M., Lopez-Gonzalez, J. and Torres-Freyermuth, A., 2013. Storm characterization and coastal vulnerability in the Yucatan Peninsula
A preliminary coastal hazard potential assessment due to storm impacts in terms of erosion and flooding for the Yucatan coast is presented. Firstly, a 30-year wave hindcast is employed in order to characterize the coastal storms by creating a 5-class storm scale in terms of wave information. Subsequently, the storm classification is converted to one based on the consequences over 26 beach profile sections located along the Yucatan coast. The storm consequences were classified according to their flood and erosion potential by means of parametric and numerical model results which are correlated with key beach characteristics such as beach width and maximum beach height. According to the obtained results, the storms were characterized in five different categories and it was found that the Yucatan coast presents higher threat to flood than to erosion during the impact of storms.
Picado, A., Lopes, C.L., Mendes, R., Vaz, N. and Dias, J.M., 2013. Storm surge impact in the hydrodynamics of a tidal lagoon: the case of Ria de Aveiro.
Storm surges are a hazardous phenomenon, since they may flood large coastal areas, causing socio-economical and habitation losses. Thus, the study of their characteristics and effects in coastal regions is crucial to prevent their negative consequences. This work aims at assessing the storm surges impact in the hydrodynamics of a tidal lagoon located in the north-western Portuguese coast (Ria de Aveiro). Storm surge amplitudes of 0.58 m, 0.84 m and 1.17 m for 2, 10 and 100 return periods, respectively, were determined adjusting the annual maximum amplitudes to a Generalized Extreme Value (GEV) distribution. To assess the hydrodynamic changes in the Ria de Aveiro under storm surge conditions, numerical modeling simulations were carried out, considering four scenarios: a single astronomical tidal forcing (reference) and astronomical tide plus 2, 10 and 100 years return period surges. Maximum levels and velocities for the entire lagoon and the tidal prism for the main cross-sections were determined and compared with the reference scenario. Generally, the model results suggest that during storm surge events the maximum levels increase in whole domain, with the largest increase found for the 100 return period storm surge scenario (1.17 m). The most significant changes occur at the main channels head for all scenarios, revealing that these regions are the most vulnerable to marginal flooding. Also, storm surges induce higher velocities and tidal prisms in the lagoon, increasing the marginal risk of erosion, as well as the salinization of the lagoon marginal lands.
Raji, O., Niazi, S., Snoussi M., Dezileau L., and Khouakhi A., 2013. Vulnerability assessment of a lagoon to sea level rise and storm events: Nador lagoon (NE Morocco)
Sea level rise is now a reality supported by scientific evidence, and coastal areas are already beginning to experience the consequences. The purpose of this work is to assess the vulnerability to accelerated sea level rise (SLR) and storm events in the barrier island of Nador lagoon, the largest lagoon (115 km2) of Morocco located along the Mediterranean coast. The vulnerability assessment was based on the combination of both a physical coastal vulnerability index and a socio-economic component, using a Geographic information system (GIS). The key results of this study are presented in vulnerability maps, and show that the Northwest sector of the barrier island is the most vulnerable area. Only the middle sector seems to be immune to the negative impacts of SLR and storm events. Human occupation of the area is mainly in the form of residential units, which represents only 3% of the total area. 20% of these units are located in highly vulnerable areas. Significant investments for future development projects are planned in an area identified as very vulnerable. This approach thus highlights the areas of the Nador lagoon where the effects of future SLR and storm events might be the greatest. Taking advantage of the currently low level of human occupation in the study zone, this information may have direct applications in coastal development programs and can assist decision-makers in the implementation of preventive management strategies in the most sensitive areas.
Raposeiro, P.D., Fortes, C.J.E.M., Capitão, R., Reis, M.T., Ferreira, J.C., Pereira, M.T.S., Guerreiro, J., 2013. Preliminary phases of the HIDRALERTA system: Assessment of the flood levels at S. João da Caparica beach, Portugal.
The length of the Portuguese coast, the severity of the sea conditions and the concentration of population and economic activities on its coastal zone justify the importance of studying wave-induced risks and, in particular, flooding due to wave action. Indeed, emergency situations caused by adverse sea conditions are frequent and put in danger the safety of people and goods, with negative impacts for society, economy and natural heritage. So, assessing the risk of flooding of coastal and port areas is essential for the proper planning and management of these areas. In this framework, a methodology for the flood risk assessment in coastal and port areas is under development. The methodology is embedded into the HIDRALERTA system, a novel integrated system for port and coastal management, designed to prevent emergency situations, to support their management and to forecast incidental long-term interventions. The present paper describes the methodology, the HIDRALERTA system and a case study, the São João da Caparica beach, on the Lisbon's area, where the referred methodology was recently applied. Sea wave characterization and flood level calculations are presented for the study.
Rebêlo, L., Costas, S., Brito, P., Ferraz, M., Prudêncio, M. I. and Burbidge, C., 2013. Imprints of the 1755 tsunami in the Tróia Peninsula shoreline, Portugal
A large earthquake shook the offshore region of Portugal in November 1st 1755 with an estimated magnitude of 8.5±0.3 in the Richter scale. It lead to the massive destruction of the city of Lisbon, which was followed by intense fires. Although most of the detailed consequences of the earthquake and tsunami focused in Lisbon, the effect of tsunami destruction was also reported in other locations along the Peninsula coasts and Morocco. At Setúbal, located 30 km to the south of Lisbon in the Sado estuary, evidences of inundation were also documented, reporting wave heights that reached a first floor height. Despite the magnitude of the inundation in the interior of the estuary, there has not been reported any evidence of the impact of this event on the estuarine shorelines. In order to understand the consequences of such a wave on the sandy shores of the region, we explore the inlet shoreline and seaward exposed region of the estuary, the Tróia peninsula. To do so, we integrate multiple types of data and information: dune ridge position were extracted from aerial photographs, shorelines from the historical maps, shoreline progradation rates, Ground Penetrating Radar profiles and optically stimulated dating of barrier sediments. This information allows us to reconstruct the shoreline following the tsunami, documenting a greater impact towards the inlet where the water flow concentrate as it entered the estuary. The impact of the tsunami in Tróia peninsula translates on the erosion of about 1000 years of barrier deposits within the spit end.
Rilo, A., Freire, P., Guerreiro, M., Fortunato, A.B., Taborda, R. 2013. Estuarine margins vulnerability to floods for different sea level rise and human occupation scenarios.
Sea level rise (SLR) is increasing the risk of flooding in marginal low-lying estuarine areas. High water levels in estuaries are associated with the simultaneous occurrence of various phenomena ranging from high tidal levels to large fresh-water discharges. The intense and diverse human occupation of some of these marginal areas increases the flood vulnerability, endangering human lives and causing heavy economic and environmental losses. This issue becomes even more relevant since the European Floods Directive establishes mandatory guidelines to all member states regarding flood risk assessment, integrating flood maps with territorial characteristics. The present study aims to assess the vulnerability to floods of a specific area in Tagus estuary, by integrating hydrodynamic modelling results with land use cartography. Results suggest that about 16.1% of the estuarine marginal fringe could be flooded for the 2050 scenario, rising up to 23.7% for the 2100 scenario. Moreover, industrial and urban areas will be the most affected sites. Considering future development scenarios planned for that site, the results point to an increasing vulnerability of urban areas and therefore to the relevance of this knowledge in future planning and management guidelines as well as measures to adapt to SLR. The uncertainties and implications of the study are also discussed, and future research topics are indicated.
Santos, M., Del Río, L., Benavente, J., 2013. GIS-based approach to the assessment of coastal vulnerability to storms. Case study in the Bay of Cádiz (Andalusia, Spain)
Storminess is considered one of the most significant natural threats to coastal areas, especially on sandy environments. When storm-related processes occur in developed areas, changes in coastal morphology are often accompanied by socioeconomic losses due to damage to infrastructure caused by erosion and flooding. The aim of this study is to assess coastal vulnerability related to storm events along a mesotidal, low-energy sandy coast in SW Spain, by analysing the main factors responsible for storm impact. This impact is considered in terms of vulnerability and coastal exposure, by the integration of physical variables (e.g. dune height or recent shoreline changes) and socioeconomic variables (e.g. land use type or population density) into a GIS. These variables are weighted and combined into two different indexes, a Physical Vulnerability Index (PhVI) and a Social Vulnerability Index (SoVI), which are then merged into a single normalized Coastal Vulnerability to Storm Index (CVSI). Results show significant spatial differences in vulnerability to storms along the study area, with the highest vulnerability level being found in the northernmost sector of the study area (Santa María del Mar urban beach), and the lowest level corresponding to the southernmost sector (El Castillo natural beach). Through the generation of colour-coded vulnerability maps, the index can be used as a guideline contributing to the determination of causes, processes and consequences of vulnerability related to storm events. Overall, the CSVI provides a rapid identification of potential risk areas, where specific intervention strategies should be adopted to prevent storm impacts.
Tõnisson, H., Suursaar, Ü., Rivis, R., Kont, A. and Orviku, K., 2013. Observation and analysis of coastal changes in the West Estonian Archipelago caused by storm Ulli (Emil) in January 2012.
The study analyzes the meteorological parameters, hydrodynamic conditions and coastal changes at three practically tideless locations on Saaremaa Island caused by storm Ulli (sustained wind speed 20 m/s, gusts 28 m/s) which struck the Estonian coast on 4 January 2012. It was the last and the most influential storm of a series of storms which began on November 2011. Wind and sea-level data from nearby meteorological and hydrological stations were used to provide the forcing data for hydrodynamic study. Wave hindcast was performed using a semi-empirical SMB-type wave model. Shorelines, scarp positions and beach profiles were measured in August 2011, and again during each of storm Berit (in November) and storm Ulli (in January). Local storm surge height reached 1 m, significant wave height (Hs) was up to 2.8 m, the combined sea level and Hs reached 3.65 m, and local wave run-up reached 3.2 m during Ulli. At Cape Kiipsaare, recession of the sandy scarp reached 9 m (at the rate of nearly 1m per hour). The loss of sand was approximately 4–5 m3 per 1 m of shoreline. Erosion occurred on the shores exposed to the prevailing wind direction while accumulation was recorded on the leeward side of the spit. Erosion mostly occurred at the elevations between 1–3 m. Although the winter 2011/12 included a series of influential storms, nearly two-thirds of coastal erosion during the winter 2011/2012 was caused by storm Ulli, which featured the highest sea levels.
Williams, H.F.L. and Denlinger, E. Contribution of Hurricane Ike storm surge sedimentation to long-term aggradation of Southeastern Texas coastal marshes
Hurricane storm surges transport littoral sediment inland and may represent an important mechanism for long-term aggradation of coastal marshes. Hurricane Ike made landfall near Galveston, Texas, on September 13th 2008, generating a large storm surge that flooded 100 km of coastal marshes in southeastern Texas between Galveston Bay and the Louisiana border at Sabine Pass. The objective of the study was to measure the contribution of the hurricane-derived sediment input to long-term marsh aggradation. A field survey of the storm surge deposit in southeastern Texas coastal marshes was conducted in January 2009 and repeated in January 2010. The results show that the deposit is well-preserved and forms a landward-tapering wedge of sandy to muddy sediments that extends hundreds to thousands of meters inland. Cesium-137 dating was used to estimate decadal-scale sedimentation rates at seven coastal marsh sites positioned along two transects beginning near the coastline and extending inland, aligned with the storm surge direction. Long-term sedimentation rates, including the sediment input from Hurricane Ike, vary from about 0.5 to 1.6 cm/year and decline with distance inland along both transects. The storm surge deposit of Hurricane Ike contributed between 42 % and 73 % of overall sedimentation at these sites in the 58-year period 1950–2008. The study findings suggest that hurricane storm surges may be the predominant mechanism for long-term aggradation of coastal marshes in the study area.
Wiyono, R.U.A., Sasaki, J. and Suzuki, T., 2013. Numerical Assessment of the 2011 Tohoku Earthquake Tsunami in Ports of Tokyo Bay with the Effectiveness of Floodgates
Floodgates were effective in reducing tsunami inundation at Funabashi and Kisarazu ports in Tokyo Bay during the 2011 Tohoku Tsunami. A numerical simulation utilizing a Finite Volume Coastal Ocean Model was carried out to demonstrate this conclusion. For the simulation, an unstructured mesh covering the tsunami propagation area was constructed. Detailed unstructured meshes at 5-m resolution were also constructed in ports and surrounding land area. Meshes were constructed using a 5-m resolution Digital Elevation Model and 50-m resolution bathymetry data. To evaluate floodgate effectiveness, potential impacts from the failure to close floodgates were investigated. An MPI HA8000 supercomputer at The University of Tokyo was utilized to execute the simulation. Simulation results were validated using inundation height data from a field survey. The effectiveness of floodgates at preventing the surrounding area from inundation is shown. When floodgates close, the surrounding area is safe from inundation. However, when floodgates do not close, the surrounding area can be inundated, and the extent of inundation can reach 620 m from the river at Funabashi Port and 450 m from the river at Kisarazu Port.
Woodward, E.M., Beaumont, E., Russell, P.E., Wooler, A., Macleod, R., 2013. Analysis of Rip Current Incidents and Victim Demographics in the UK
Rip currents are responsible for 67% of all individuals rescued by lifeguards on UK beaches, representing the greatest environmental risk to water users. There are currently no measures of human awareness of rip currents in the UK, and the worldwide research on human behavioural aspects surrounding rip currents is a small emerging research area. In the last few years the physical understanding of rip current behaviour has been much improved by studies using GPS floats. The aim of this study is to discover the key demographic characteristics of beach users caught in rip currents and the spatiotemporal variation in the UK by analysing the Royal National Lifeboat Institutions lifeguard rip current incident data for 2006 to 2011. The results show male teenagers (aged 13–17 years) are the most likely demographic to be involved in a rip incident., In addition, people bodyboarding, and people in non-patrolled areas of the beach are at higher risk. Rip incidents are most common on the popular Atlantic-facing beaches of north Devon and Cornwall where low-tide bar-rip morphology enhances rip current activity, presenting a major hazard to beach users. This study presents a significant insight into rip victim demographics, identifying key target audiences for future awareness campaigns and rip education schemes. It also provides a benchmark for further research into the investigation of why specific demographics are getting caught in rips by understanding the behaviour of these groups.
Yoon, J.J., Shim, J.S., 2013. Estimation of storm surge inundation and hazard mapping for the southern coast of Korea
The coastal area of Korea is damaged by the approach of typhoons every year. The most serious inundation damage, with loss of lives and properties, was caused by typhoon Maemi in September 2003. After this event, there has been increased interest in addressing these coastal zone problems. It is therefore desirable to accurately forecast the storm surge height. In this study, using a numerical finite-volume coastal ocean model (FVCOM), a storm surge was simulated to investigate its inundation characteristics for the coastal area at Masan, Yeosu and Busan cities on the southern coast of Korea. In the model, a moving boundary condition (wet-dry treatment) was applied to examine inundation propagation by storm surge. The model grids were extended up through the lowland area by applying the DEM, made by precisely combining the airborne-LiDAR survey and bathymetry data. A minimum 30 m resolution unstructured triangular mesh was applied to calculate the storm surge and inland inundation. Simulated inundation range and depth were compared with the inundation map made from field measurements after the typhoon event. The results of inundation simulations in this study show good correspondence with not only the observed inundation area but also inundation depth. We also estimated the special inundation level distributions for each return period. The numerical model system adopted in this study could be a useful tool for analyzing storm surges, and for predicting coastal inundation. In addition, it is necessary for preparing detailed evacuation plans, including hazard maps for associated storm surge inundation problems.
Antso, K., Kont, A., Palginõmm, V., Ratas, U., Rivis, R. and Tõnisson, H. 2013. Changing natural and human impacts on the development of coastal land cover in Estonia.
The structure of coastal land cover in Estonia is variable and shows considerable differences from site to site. The diverse geomorphology of the seashores is one of the key factors causing different velocity and magnitude of changes while the country's history of settling the coast has also shaped the character of land cover. The main objectives of the current paper are: 1) to give an overview of land use and the trends of development of land cover pattern in different parts of the Estonia's coast; 2) to analyze the relationships of natural and man-induced processes and their cumulative impact on the evolution of coastal land cover pattern in Estonia. The current paper focuses mainly on changes in land cover in agricultural areas and on small islands. In predominating agricultural coastal areas, the traditional open landscape of fields and grassland in the beginning of the 20th century has been replaced by woodland and grassland with shrubs by the start of the 21st century. Expansion of reed beds in the areas of former seashore grasslands is another striking phenomenon. The evolution of the landscapes on small islands is strongly dependent on the character of their formation and is well reflecting the relationships of vegetation, topography and moisture conditions. Cessation of traditional land use, rapid increase in coastal population and expansion of built-up areas in recent decades, together with higher storm activity, create stresses on the coast that threaten both nature and man.
Bacci T., Rende F.S., Nonnis O., Maggi C., Izzi A., Gabellini M., Massara F., Di Tullio L., 2013. Effects of laying power cables on a Posidonia oceanica (L.) Delile prairie: the study case of Fiume Santo (NW Sardinia, Italy).
Coastal areas are complex systems where both marine ecosystems and human activity interrelate, often raising several conflicts. The economic activities may, sometimes, disturb the functioning and stability of coastal ecosystems, particularly of the seagrass meadows, and menace their future existence. In the Mediterranean Sea the most important seagrass is Posidonia oceanica (L.) Delile, an endemic species, which meadows have been defined priority habitats following the 92/43/CEE Directive. Therefore, all technical solutions for cables or pipelines installation across a P. oceanica prairie should be adapted in order to protect these ecosystems and to prevent their degradation allowing the maintenance of a satisfactory state of conservation. In this work we present the results of an environmental study carried out in NW Sardinia coast (Italy), where three marine power cables were laid from 2007 to 2010. The technical project, named SAPEI, provided the electrical connection between Sardinian coast and Latium coast through the Tyrrhenian Sea. In the coastal areas colonized by P. oceanica prairies cables were lying on the seabed and anchored with appropriate anchoring devices, placed manually by divers, in order to avoid any damage to the meadows and to prevent cable sliding. Environmental investigations were carried out before, during and after cables installation in order to understand and define how cable laying can interact with seabed. From the end of 2007 to 2011 qualitative (three times a year) and quantitative (once a year) surveys have been performed along the cables routes. Results of environmental monitoring has allowed us to know the health state of P. oceanica in the interested area and it has allowed us to assess, over time, the interactions between seagrass prairies and power lines placed and anchored on it.
Bentz, J., Dearden, P., Calado, H., 2013. Strategies for marine wildlife tourism in small islands – the case of the Azores
Small islands typically exhibit characteristics like isolation, smallness, limited natural and human resources, which limit their capacity to embrace development. Marine wildlife tourism (MWT) can combine the apparently conflicting goals of development and conservation. It has a potential to provide significant benefits to local communities and ecosystems, when it is carefully managed. The Azorean islands have a great potential for MWT, given highly diverse marine ecosystems and various types of resident and migrating cetaceans. Several MWT activities are taking place though lacking effective management. Whale watching and other MWT activities such as scuba diving have an increasingly important role within the tourism sector, as the Azores offer good conditions for watching oceanic species close to the shoreline. Recently shark-watching demonstrated potential for a new MWT activity. Managing these new emerging activities is required. There is no island or regional-wide strategy for MWT in the Azores, assessing its potentials and impacts and making recommendations on how it can be developed in a sustainable manner. The goal of this project is to contribute to the sustainable development of small island economies through developing guidelines that will ensure MWT as a mechanism to conserve nature while supplementing local livelihoods. A specific objective is to develop a conceptual model of MWT for small islands that can be integrated in regional planning instruments and apply the model to a specific case study, in order to recommend the optimal development strategies and necessary management interventions for MWT development in the Azores. As a first approach, experts and stakeholders of the whale watching industry were interviewed in order to develop an understanding about their interests and perceived problems of the activity in the Azores. The results showed various management gaps. The opinions of the interviewees differed especially upon the management of the activity and its current sustainability. It proved the necessity for further research to assess the effectiveness of management policies using an integrated approach that incorporates both social and biological aspects of this and other MWT industries. The authors suggest multidisciplinary, participatory approach for effective co-management, providing a holistic view of the problem and forming the basis for adaptive management and thus the long-term sustainability for the activity.
Botero, C., Anfuso, A., Williams, A.T., Zielinski, S., Silva, C.P., Cervantes, O., Silva, L., Cabrera, J.A. 2013. Reasons for beach choice: European and Caribbean perspectives
Beach users' preferences range greatly according to their cultural and educational heritage, national and local traditions, social status, sex, etc. Questionnaire surveys carried out on beach user preferences (50 beach aspects) in Wales, UK (n = 2,345); Hollywood beach, Florida, USA (n = 83), the Costa Dorada, Spain (n =157); Malta (n = 154) and Turkey's Aegean coast (n = 245) showed that five parameters were of the greatest importance on beach choice: safety, facilities, water quality, litter and scenery. Such kind of detailed surveys has never been carried out in Caribbean countries. Consequently, a great uncertainty exists regarding beach users' preferences. During Easter 2012, a total of 435 beach users along eight beaches of the Caribbean littoral of Colombia (Mayapo, Riohacha, Taganga, Rodadero, Puerto Colombia, Salgar, Bocagrande and Manzanillo) were interviewed. Specifically, persons were asked (i) to choose from a list of parameters, the three most important aspects to be taken into account in choosing a beach and (ii) the reason they decided to visit that specific beach. Dealing with the former, results differed from ones recorded in Europe in that scenery was deemed not to be important. Concerning the latter, great variety of responses was recorded but the main aspect in beach selection was “proximity” for both local and national visitors. Aspects such as “a relaxed friendly” atmosphere and “party atmosphere” were mentioned. In this sense, it is interesting to notice the particular perception that Caribbean beach users showed for the “relaxed friendly” atmosphere. On many occasions beaches classified as such, were very crowded and extremely noisy because of loud music and peddlers. Results obtained constitute a first step in the knowledge of Caribbean beach users' preferences and therefore is one, which is of a great importance for beach management.
Camacho, R.A. and Martin, J.L., 2013. Bayesian Monte Carlo for evaluation of uncertainty in hydrodynamic models of coastal systems.
Uncertainty analysis constitutes the set of procedures and strategies conducted to identify, quantify, and report the impacts of different sources of errors on the predictions of a numerical model. Although during the last couple of decades several investigations in different areas of water resources have explicitly discussed the importance of a new modeling paradigm where model predictions are reported along with uncertainty estimates, uncertainty analysis remains an emerging topic in the field of hydrodynamic modeling. Presently, several unresolved issues remain with regard to the applicability, benefits, and limitations of existing strategies for quantification of uncertainty, and the identification of the principal sources of uncertainty in practical applications.
In this document we apply the Bayesian Monte Carlo (BMC) method as a strategy to perform uncertainty analysis in coastal modeling studies. BMC is based on robust principles of Bayesian inference and Monte Carlo simulations, and has been successfully applied for studies of groundwater modeling, hydrologic modeling, and water quality modeling in the past. The procedural aspects of the method are discussed in detail, and the implementation of the method is demonstrated for the hydrodynamic model of the St. Louis Bay estuary, Mississippi (USA) for the evaluation of the impacts of input data errors. Results indicate that BMC is an effective strategy for uncertainty analyses, although in professional practice its use may be limited by computational requirements. We also point out that the effectiveness of the method may be affected by the correct selection of the likelihood function and the model error variance.
Carrasco, A.R., Ferreira, Ó., Matias, A, 2013. Managing flood risk in fetch-limited environments
There is little unanimity concerning the environmental modifications potentially forced by the acceleration of global climate change in the coming century, or the future actions required to work towards a sustainable development of natural habitats in the coastal zone. A simple framework to assess the potential implications of flooding in fetch-limited coastal environments (with no relevant wave setup), experiencing both coastal and river flooding, was recently developed. It identifies tide, storm surge, sea level rise and river discharge as the main sources of flooding hazards. Hazard maps differentiate distinctive zones of flooding: the constantly flooded zone, the frequently flooded zone, and the infrequently flooded zone.
The framework prioritizes site-based local management, and identifies alternative tools for sustainable coastal resources, to face non-desired flood effects. It was applied to a morphologically complex (tidal channels network, salt marshes, dunes) occupied backbarrier coastal stretch located in Culatra Island, South Portugal (max. fetch ~ 4 km). The obtained inundation levels predicted for 1, 10 and 100 year-return periods were 2.02 m, 2.39 m, and 2.84 m above MSL, respectively. The high-, moderate-, and low-risk zones include about 34 m2, 1,073 m2 and 31,821 m2 of occupied area, respectively. Besides houses, flood impacts also affect other infrastructures (e.g., walkways and recreational structures). Several best practices principles and guidelines were proposed for the three risk zones, namely the adaptation to uses with ‘added value', which enhances the local ecological values and strengths economic activities. This study contributes to the method validation at a complex morphological area and enriches the understanding about the potential of flood in fetch-limited conditions, praising the perspective of ‘living with climate change'.
Carrero, R., Navas, F., Malvárez, G., and Cáceres, F., 2013. Participative Future Scenarios for Integrated Coastal Zone Management.
Coastal zones are rapidly changing all around the world due to strong human pressures such as urban sprawl, agriculture intensification, infrastructure expansion and industrial growth. In addition, climate change might become an important factor in the years to come, and its associated effects might affect coastal areas. To cope with this situation the need to adopt an Integrated Coastal Zone Management (ICZM) approach has been internationally recognised during the last decades. Nonetheless to be able to plan and manage coastal areas in the long-term while facing all the challenges that lie ahead, it is necessary to develop new tools that not only put into practice the ICZM principles but also incorporate and deal with the uncertainties that surround the future. In this paper, we present Participative Future Scenarios (PFS) as a tool to support decision-making in coastal areas under the ICZM principles. PFS allow exploring how coastal areas could develop in the future, using an integrative approach that combines quantitative and qualitative methods, taking into consideration coastal hazards and climate change, as well as human interaction, as the process is based on participatory techniques involving local stakeholders. The process carried out to implement PFS at the local scale has been pilot-tested in the Andalusian coastal municipality of Ayamonte, South Western Spain. Four well-differentiated scenarios showing alternative and plausible futures for the study site for the year 2050 were obtained. The result of this pioneer exercise points out that PFS are a powerful and ground-breaking tool for ICZM with a double potential: i) The generation of PFS is a valuable exercise per se as it provides an opportunity to promote participation, understand public's different opinions, facilitate communication between stakeholders and increase public awareness about coastal future problems (e.g. coastal hazards). ii) PFS can be-and should be- used as part of the decision making process for coastal planning, allowing policies to be designed in a more robust manner, accounting for critical uncertainties -as diverse as economic fluctuations or climate change- and helping to select the path to the most desirable future. Additionally, the PFS process proposed in this paper is a transferable technique that can be easily replicated in other coastal areas.
Nelsen, C., Cummins, A. and Tagholm H., 2013. Paradise Lost: Threatened Waves and the Need for Global Surf Protection
Ocean waves are an integral part of the marine system, providing recreation and economic values to coastal communities around the world. Worldwide, the importance of surfing is consistently undervalued. As a result, there are numerous examples around the world where surfing waves are currently under threat from inappropriate development. Many more surfing waves have already destroyed by development.
There are numerous discreet threats to surfing waves around the UK coastline. UK-based Surfers Against Sewage (SAS) is promoting the value of waves with the Waves Are Resources (WAR) Report and the Protect Our Waves (POW) petition calling for specific legislation to better protect surfing waves around the UK.
Internationally, the Surfrider Foundation successfully stopped a proposed six-lane toll road that would have destroyed a popular state park and degraded a world famous surfing area called Trestles. The project was opposed by thousands of water users, supported by a surf economics report. Surfers visiting Trestles contribute to San Clemente's local economy by spending money when they visit and contribute between $8 and $13 million a year to the local economy.
This paper presents an overview of the importance of surfing to coastal communities, provides an overview of threats to surfing around the globe and cases studies on successful efforts to protect surfing through coastal management, planning and legislation. The findings demonstrate the significant economic, social and environmental importance of surfing amenity to specific locales and support the need for appropriate consideration of impacts to surfing that may occur as a result of coastal management decisions.
Choi K.H., Kim, Y.M., and Jung, P.M., 2013. Adverse effect of planting pine on coastal dunes, Korea.
Forestation on the coastal dunes has been regarded as one of the best programs that help to stabilize the dune landscapes and protect the residential area from strong winds, blown sands, and salt spray. Introducing exotic species for dune stabilization was very common in the past. However, it could deprive coastal land of its ability to naturally recover, causing a retreat of coastline as well. As a typhoon passed through the Korean Peninsula early September in 2010, coastal dunes along the west coast of the peninsula were severely damaged during the storm. Some dunes retreated landward more after erosion, while others recovered their original profile through aeolian transport processes mainly in winter season. Vegetated dunes with pine trees recovered relatively less after the erosion than grass-covered dunes. Planting pine trees may interfere in these interactions, weakening natural recuperative power. We compared the characteristics of wind environment, morphology, and vegetation between the grass-covered dunes and the dunes covered with pine trees, for the purpose of the effectiveness of planting trees on dunes. The pine forest decreases the wind velocity on the front side of the dune to less than 50% of the grass-covered dune. Especially, the velocity of the strong winds faster than 4.5 m/s diminished to 25% of the control sites, resulting in decreased blown sand supply. Flora is also changed in the forested area. Terrestrial plants have invaded after pines were planted. In contrast, natural flora gets disappeared after the introduction of alien and exotic species. This study suggests that planting tree is likely to lead negative impact on coastal dunes. It may result in a retreat of coastline, loss of land, and devastation of dune ecosystems.
Clarke, B and Harvey N., 2013. Wither coastal management in Australia—a call for National Leadership
The prominence of the coast in terms of the Australian Government's policy has significantly diminished over the last decade. With the exception of planning for climate change and sea level rise there is an absence of forward thinking for the coast at the national level. This absence of national contribution towards direction setting has a filtering effect upon the states. Australia's coastal environments are highly varied and exhibit an impressive array of habitats and species. A federal role in coastal management in Australia is warranted because nationally coastal resources have important social, cultural and economic status. However, important aspects of coastal management have been largely neglected in recent years (integrated management, coastal natural resource management, marine and estuaries planning). This is evidenced by the abolition of the key federal governmental committees and agencies that had a direct mandate for the coast. It is argued that national leadership is critical to support and coordinate what has in the past a somewhat disparate and fragmented allocation of effort and funding. This paper provides an analysis of recent changes within the Australian Government and coastal management decision-making, funding allocations and initiatives and governance; and proposes a series of recommendations for possible ways forward.
Costa, S. and Coelho, C., 2013. Northwest coast of Portugal Past – behavior and future coastal defense options
Portugal's northwest coast, between Ovar and Marinha Grande presents an important sediment deficit, mainly due to rivers sediments supply reduction and harbors' constrains. The sediment transport capacity resulting from the wave's action (mainly from the northwest) is nourished with the sand of the up drift beaches, leading to the shoreline's erosion and retreat. The shoreline retreat represents conflicts with the land use and human occupation, and the protection of people and properties becomes essential. Thus, coastal interventions (seawalls and groins), try to constrain the shoreline evolution, conducting to an artificial coast and site aesthetical deterioration. This work's objective is to present an analysis of the shoreline evolution, in order to select a suitable model of coastal intervention. Thus, the current paper aimed a diagnostic based in the shoreline evolution indicators in the period between 1994–2011: a) average rate of shoreline retreat; b) number of coastal defense structures implemented; c) number of coastal emergency works and interventions; and d) number of registered events related to shoreline retreat (overtopping, dune system and coastal structures partial destruction). This analysis highlights the location of the most vulnerable areas. Furthermore, different scenarios of coastal defense interventions are discussed, having as variable the associated investment costs, which represents different strategies and impacts, namely: a) maintain the existent coastal defense structures; b) adapt the existent coastal defense structures; c) perform artificial nourishments; and d) propose new coastal defense solutions.
De la Torre Y, Balouin Y., Heurtefeux H. and Guérinel B., 2013.The “Storm Network” as a participative network for monitoring the impacts of coastal storms along the littoral zone of the gulf of Lions, France
The French coast of the Gulf of Lions is a low-lying coastal plain where humans have strongly developed infrastructure and urbanized the coastal zone, disregarding the potential impact of extreme events. This results in an increase of coastal vulnerability to extreme storms with damage to harbor facilities, coastal tourism infrastructures, and urban infrastructures. To improve the management and prevention of such threats on the coastal zone, a monitoring network of coastal storms and the resulting impacts was created. The aim of the “Storm Network” is to obtain good quality and homogeneous data along the entire Languedoc-Roussillon coastline to enhance the regional knowledge on coastal extreme events and their impacts and to validate morphological models. According to the analysis of all historical events, an assessment of three thresholds of morphological impacts was done, basing on the offshore significant wave high indicator. A monitoring program was defined with three corresponding levels of intervention such as: level 1 (3m<Hs<4m) for physical information gathering with no field visit required; level 2 (4m<Hs<5m) qualitative field observations; level 3 (Hs>5m) additional quantitative surveys and numerical modeling. In order to anticipate the event, an operational model for wave forecasting is used (WW3 Mediterranean model, by Ifremer). When reaching the defined levels, an automatic email is sent to the operators of the network to prepare the intervention. The Storm Network was implemented in 2011, was activated during the winter 2011/2012 and is currently running. It permitted to localize precisely the storm impacts and to analyze their spatial variability.
Esteves, L.S., 2013. Is managed realignment a sustainable long-term coastal management approach?
Concerns about sea-level rise and nature conservation led to a shift from hard engineering to more sustainable management approaches. Managed realignment (MR) is increasingly popular in Europe, especially in England where projects often have multiple aims, including: intertidal habitats creation, improved flood risk management and more affordable coastal defences. This article discusses whether MR is a sustainable strategy able to deliver the expected environmental and socio-economic benefits in England. Assessing the sustainability of MR is problematic, as data on projects' performance are scarce, of restricted dissemination and limited in scope and geographic coverage. Additionally, projects lack well-defined targets against which their performance can be evaluated. The few existing independent studies indicate a number of constraints including: reduced biodiversity in small realignment sites; new saltmarsh development at the expense of established habitats; poor ecosystem services provision; and lack of understanding about the effects of MR on hydrodynamic and sedimentary processes. There is little evidence so far that MR in England is achieving its strategic aims. Realignment sites are usually small, confined by new defences and located within or adjacent to designated conservation areas, where conflicts arise as designated freshwater habitats might be destroyed to give place to intertidal habitats. As sea level continues to rise, it is just a matter of time for coastal squeeze to affect the newly created intertidal habitats. Only through a coherent, long-term and national strategy that truly integrates planning, flood management and conservation objectives, MR will be able to deliver the expected benefits.
Fernández Carrasco, P., Pozo Menéndez, E., 2013. Chilean Caletas: more than artisan fishing villages.
As is widely known, Chile is a country characterized by its vast expanse of coastline, one of the main factors that have shaped Chilean culture throughout its history. Local people have been exploiting marine resources since records began and, currently, fishing is still one of the strongest economic sectors. Artisan fishing villages, are placed in this context. In 1998, more than four hundred fishing villages were legally recognized along the coast. Since then, they have been gradually regularized in order to protect fishermen's activity as well as to ensure the development of marine environment. In the last years, these villages have experienced a huge population growth, despite local infrastructures and equipments showing a lack of basic services and an unstable situation which could be categorised as poverty. The main objective of this research work is to analyse every fishing village by using particular and global approaches. This will lead us to the formulation and compilation of several development projects in order to allow the fishing villages to be considered as a main factor in coastal management, policy and planning. In addition, we have started the creation of a dynamic database that will offer a great opportunity to share information at different levels, by means of connecting local people with experts related in many different fields. Thus, an alternative answer to coastal development is proposed, including the three main sustainable characters: society, environment and economy.
García, M., Abogado, M. T., Pérez, F., Castillo, A., García, S., Marín, J., Morales, J. and Duarte, J.F., 2013. Developing Management Strategies for Coastal Public Domain in Venezuela: From Local Delimitation to National Implementation
Coastal public domain constitutes the area of interaction between land and sea. For its nature, is very dynamic due to the advance and retreat of the coastline. In Venezuela, coastal public domain is legally considered in the Law of Coastal Zones as an area to be delimited for conservation and public use purposes. The boundary of coastal zone has not defined, resulting in the inappropriate use of ecosystems and natural resources through incompatible developments with planning proposals. This article aims to establish criteria to define the boundaries of coastal public domain and to apply directives and guidelines in this space. These are derived from the National Policies for Conservation and Sustainable Development of Coastal Zones in Venezuela, established in 2010. The areas of study, Patanemo and Playa Coral - Bahía de Los Niños, have different natural characteristics and degrees of intervention. In both areas, a diagnosis was done and the coastal public domain boundaries were defined based on five (5) criteria. Used criteria are fully integrated into the physical, biotic aspects and risk management, allowing efficient planning. For Patanemo, three (3) directives and five (5) guidelines were applied. For Playa Coral - Bahía de Los Niños, two (2) directives and four (4) guidelines were applied. The directives and guidelines are adjusted to the natural characteristics of each area. A nationwide strategy to define and manage coastal public domain is to be established.
Gracia, V., García, M., Grifoll, M. and Sánchez-Arcilla, A., 2013. Breaching of a barrier beach under extreme events. The role of morphodynamic simulations
A study of three breaching episodes of the Trabucador barrier beach (Spanish Mediterranean coast) is presented. The analysis is done from a modeling perspective using XBEACH and SWAN. The morphodynamic model (XBEACH) has been validated with the available information. The so obtained Brier Skill Score index has been 0.44 which can be considered as acceptable. Results indicate that in all cases breaching was taking place after 8 hours of wave action (storm) or less. Besides, four main parameters control the final morphodynamic response of the barrier: the storm intensity, the water level and the initial emerged topography and the storm duration. Major breaching occurs when swell waves are in coincidence with high water levels whereas if they are uncoupled the barrier tends to be breached by a diversity of smaller channels.
Helzel, T., Hansen, B., Kniephoff, M., Petersen, L., Valentin, M., 2013. Ocean Radar for Monitoring of Coastal Zones – new aspects after getting a world wide frequency allocation for these instruments
For more than 20 years, Ocean Radars have proved their reliability for diverse oceanographic application purposes and prediction situations. However, they were operating as systems on experimental license basis only. At the World Radiocommunication Conference 2012 (WRC-12) the International Telecommunication Union (ITU) has for the first time officially recognised oceanographic radar. This paper shows how in the future, primary (under some restrictions) and secondary frequency bands will be allocated worldwide for these powerful oceanographic sensors and how these bands allow to use the instruments for long and short ranges with a spatial resolution of up to 300 m. This step forward for the Ocean Radar result into a change from being experimental systems to operational applications. As a conclusion this will attract new potential users and the scientific community should use this opportunity to initiate new research projects. Samples from various applications and different validation studies with the ocean radar WERA demonstrate the advantage of this ocean radar technology. Especially the land-based installation of these systems make them attractive as they are easy to deploy and provide a very good data availability at low costs with the convenience of on-shore installations. Some ideas for new applications are introduced.
Jang D., and Hwang, J. H., 2013. Classification method of estuary considering the climate change in South.
Sea level rise attributed to climate change is expected to affect the estuaries of South Korea significantly. The seawater intrudes into the beds of river channels and into aquifers near the coastal zone, and such processes are expected to be magnified in the climate change regime. Further, flooding and erosion are expected to be intensified at the shorelines of rivers and in coastal zones. Such adverse effects are expected to occur, which will depend on the individual characteristics of different estuaries. Some of these characteristics include the volume of a tidal prism, the length of shoreline peripheral, and the bathymetries in the estuaries. Our present work modified the existing estuary classification systems to be more responsive to climate change; in particular, we have included the wave change impact. Many studies have proposed estuarine classifications recognizing the various features of each estuary. There are several ways to classify estuaries. First, estuaries can be classified with the Estuarine Circulation Classification (ECC) system. Second, Geomorphological Classification (GC) categorizes estuaries with the dominances among physical components. Third, Estuary Environment Classification (EEC) classifies with indices representing the physical processes and estuary shapes. However, these existing methods did not involve qualitative categorizations and also excluded the wave factor. They also did not include a category for the artificial estuaries, which are prevalent in Korea. Therefore, efficiently constructing a comprehensive response plan for the climate change based on these existing classification systems was not possible. Thus, a new quantitative method including the wave index and considering the artificial estuary is proposed here that can be utilized in a response to climate change.
Khouakhi A., Snoussi M., Niazi S., Raji O., 2013. Vulnerability assessment of Al Hoceima bay (Moroccan Mediterranean coast): a coastal management tool to reduce potential impacts of sea-level rise and storm surges
Projected increases in sea level rise (SLR) and in the magnitude and frequency of extreme weather events pose a major challenge for the management of low-lying coastal ecosystems and human settlements in the context of climate change. The bay of Al Hoceima is one of the least studied and largest low-lying coastal areas of the Moroccan Mediterranean coast, and is highly exposed to the effects of SLR and storms. The coast is also a touristic area and one of the most important economic assets in the region of Al Hoceima. Physical coastal vulnerability assessments are one of the principal tools for developing coastal management plans. Here we assess the vulnerability of the coastline to sea level rise and extreme weather events through a standard index methodology based on physical indices, before carrying out a socio-economic evaluation of potential impacts in the area. Using a combination of high resolution maps and remotely- sensed data, we selected the five most relevant physical parameters for local-scale vulnerability analysis, based on 50m/50m cells along the coastline . A total of 822 cells were identified and evaluated, with individual parameter scores ranging from 1 to 4 and calculated total scores from 10 to 20. We found that 41% of the studied coastline is highly vulnerable to the effects of SLR and extreme weather events. These findings will have direct repercussions for coastal development programs over both the short and long terms.
Kim, D.S., Hong, S.J and Park, H.S., 2013. Analysis of evacuation system on tsunami disaster prevention in Korea.
The purpose of this study is to develop tsunami hazard maps by analyzing the coastal inundation characteristics on the eastern coast of Korea. The Korean peninsula is mistakenly considered to be a country safe from tsunamis as it is located next to Japanese islands which are believed to act as a barrier in various disaster situations. However, in reality, it is rather disaster-prone as it is located in the seismic zone along the western coast of Japan in the East Sea. To date, five tsunamis have affected Korea, including the Kanpo tsunami in 1741, the Shankotan tsunami in 1940, the Niigata tsunami in 1964, the Central East Sea tsunami in 1983, and the Hokkaido south western tsunami in 1993, of which the Central East Sea tsunami and Hokkaido south western tsunami resulted in casualties and caused property damages, especially in the Gangwon province. In this study, future tsunamis with a high probability of occurrence are investigated through an analysis of the seismic zone in the East Sea. For the analysis, hypothetical tsunami scenarios are developed to examine the inundation characteristics and create tsunami hazard maps of the eastern coast of Korea; tsunami inundation characteristics are analyzed for the subject areas based on the numerical simulation results using different scenarios. According to the analysis, tsunamis tend to land in the eastern coastal areas of the Korea peninsula due to bathymetric features of the East Sea. Furthermore, tsunami heights are calculated to be up to twelve meters above mean sea level (MSL). Finally, the tsunami hazard maps are developed based on the inundation analyses of the study areas. By developing tsunami hazard maps, inundation areas, evacuation routes, and shelters can be easily predicted, established, and selected. In non-emergency situations, tsunami hazard map can be used for education and promotion purposes and as a reference for risk assessment and disaster prediction.
Kim, J. and Park, J., 2013. A statistical model for computing causal relationships to assess changes in a marine environment
In order to manage sustainable coastal development, it is essential to identify the causal relationships among observation parameters that reveal the changes in the marine environment in a quantitative manner. On the Saemangeum coast, a land reclamation project by constructing sea dike has been underway since 1991. To monitor and assess the changes in the marine environment due to the project, the states of the ocean's physics and circulation, water quality, marine geology, and the marine ecosystem have been measured through the integrated ocean observation networks. In this paper, the observed data are statistically investigated with regard to observed and latent variables, in order to identify their causal relationships and compute the degrees of their influence. We performed a multivariate statistical analysis using a structural equation model based on oceanographic theory using the monthly mean observed data. As a result, 15 principal components were extracted and the statistical model was obtained by estimating the standardized regression coefficients of the observed variables and the latent variables, as well as those between the latent variables. The statistical model was applied to both the inner reclaimed area and the outer sea area individually to verify the model quantitatively how well it explains the changes of marine environment due to the blocking of seawater exchange in the inner reclaimed area comparable to the outer sea area separated by the sea dike. Our results show that the proposed statistical approach is quite suitable for understanding phenomena in ocean science that occur causally by identifying theoretically-known causal relationships quantitatively. By predicting the various impacts on environmental changes in advance through the quantitative estimation of a statistic model, we can prepare appropriate countermeasures or alternatives for preserving and protecting the environment, whose vulnerability is an inevitable result of such development. In this respect, our study can be effectively utilized as a tool for coastal management, policy-making, and planning.
Landim Neto, F.O., Gorayeb, A, Silva, E.V, Pereira Filho, N.S, 2013. Application of the DPSIR model to an estuary of the Brazilian Northeast: a tool for local and regional management
The occupation and use of coastal environments are characterized by a general lack of planning, which provokes increasing pressures and the progressive intensification of problems such as deforestation, the pollution of water resources, inadequate disposal of solid waste, and the illegal occupation of public areas. The present study proposes a diagnosis of the environmental quality of the Guaribas estuary on the western coast of Ceará, in northeastern Brazil, based on the application of the DPSIR model (Driving Forces, Pressures, State, Impact, Responses). In the field, geographic coordinates were collected (GPS navigator), providing the data for the production of maps in an SIG environment, based on the interpretation of high spatial resolution satellite images. Based on the observed constraining factors, it was possible to predict eventual impacts, such as a reduction in fishery productivity, loss of habitats and biodiversity, and numerous problems in the sphere of public health. The appropriation of space was clearly related to the installation of the Pecém shipping terminal and industrial complex, as well as hotels financed by foreign investments attracted by the economic development policies of the state, which conflicts with the interests of the traditional local communities and creates a marked imbalance in the use of coastal space. The results of the present study indicate that the DPSIR model represents an excellent analytical tool for the evaluation of the local scenario, given the integrated analysis of socio-environmental problems, in addition to the identification of potential strategies that may be adapted to the perspective of public authorities, the economic sector, and society in general. Overall, there is clearly an urgent need for the regulation of the use of the coastal environments of western Ceará, Brazil.
Lee, H.S., Kim, I.H., Song, D.S. and Lee, J.L., 2013. A Correlation Analysis between a Swim Zone Width and Beach Survey Data in Sokcho Beach
Sokcho Beach is the 3 km-long sand beach located on the east coast of South Korea. Beach profile surveying and grain size sampling in four control sections were carried out in order to investigate the relationships of swim zone width between the median size, beach face slope, and scale factor. It is found that temporal variation in the southern part of beach is the most severe due to the presence of Oeongchi headland. As the result of the correlation analysis, the correlation factor of the swim zone width to the scale factor was estimated rather high (0.596). The present study shows the grains size is not an adequate indicator in estimating the swim zone width. Regular monitoring of the region is required to determine the seasonal changes, the sediment transport, and the changes in the sedimentation environment, and to acquire an accurate understanding of the beach environment and of the changes that it is undergoing.
Martín-Prieto J.A., Roig-Munar, F.X., Pons G.X., Rodríguez-Perea A., Alvarado, M. and Mir-Gual M. 2013. Description of erosion processes in Spratt Bight (San Andrés Island, Colombia) using Sequential End Point Rates (EPR).
San Andrés is a coral island located in the Colombian Caribbean, 700 km northwest of the main land. Twelve kilometers in length and three kilometers in width, it is one of the most populated islands with 2.612 inhabitants per square kilometer. Its economy is based on tourism. Despite being protected from storms and hurricanes by a chain of reefs that stretches across the north and east of the island, beaches suffer significant erosion. Spratt Bight is the biggest and the most important beach of the island. Temporal evolution of Spratt Bight was analyzed and the End Point Rate for several periods (from the year 1984 to 2010) has been calculated. Although beach nourishment between 1984 and 1990, erosive processes are dominant all over the beach. Erosion rates reach up to 35 m with an average of −1.3 m/year, in its central part. The other erosive sector is placed in the half north of the beach, with a maximum of 20 m and an average of −0.7 m/year. Detected erosion can be attributed to the construction of two perpendicular structures to the shoreline and a promenade located on top of the upper beach. The rigidity of these facilities does not allow the natural evolution of the beach, disconnecting the beach from the dunes and causing significant losses of sand by wind action.
Mosadeghi, R., Warnken, J., Mirfenderesk, H., Tomlinson, R., 2013. Spatial uncertainty analysis in coastal land use planning: a case study at Gold Coast, Australia.
Vulnerability of coastal areas to the global environmental changes and uncertainties in climate change predictions, particularly at local scales has presented a challenge to land-use planning in coastal cities. To make more accurate decisions, the uncertainty due to imperfect knowledge (epistemic uncertainty) is required to be considered in tandem with the inherent uncertainty or randomness of nature, and socio-economic dynamics (stochastic uncertainty). This paper examines the application of spatial Multi-criteria Decision Making (MCDM) tools to evaluate the effects of uncertainties at each stage of the decision- making process. The north east Gold Coast, Queensland (Australia) was considered as a case study to evaluate the sensitivity of the land-use planning decisions to input uncertainties. Uncertainty analysis in the framework of MCDM has been performed to address epistemic uncertainty. To examine the effects of uncertainty in a spatial context, conventional uncertainty analysis was combined with the visualisation capability of GIS and Monte Carlo simulation algorithm. The analysis results graphically display the sensitivity of output to the uncertainties in inputs and present a promising way to assist more transparency in the decision-making process.
Paganelli, D., La Valle, P., Ercole, S., Teofili, C., and Nicoletti, L., 2013. Assessing the impact of coastal defense structures on habitat types and species of European interest: a methodological approach
Mediterranean coastal zones generally present high environmental value and high biodiversity, and are characterized by the presence of a large amount of protected environments and species of European interest. The Mediterranean coastal environments are extremely sensitive and vulnerable transitional zone and they are strongly influenced by human activities (industries, tourism, shipping, fisheries and aquaculture/agriculture activities etc.), which affect the natural evolution of this complex system. The available literature also reports that about 15,100 km of European coastline is undergoing retreat. Within this context, ISPRA has developed a specific methodology aimed at evaluating the potential impacts of coastal defense structures on protected habitat types and on the related flora and fauna species. This approach was developed and shared within the framework of the Component 5 of the COASTANCE Project entitled “Guidelines for Environmental Impacts Studies focused on coastal protection works and plans”. The methodological approach proposed is subdivided into the following steps: 1) identification of the main coastal defense structures and their main potential environmental impacts; 2) identification and classification of the marine-coastal habitat types sensu Habitats Directive; 3) definition of the criteria required to associate the protected flora and fauna species with the different physiographic categories; 4) creation of the “impact vs habitats and species” matrix-system. The proposed methodology is a multi-disciplinary tool that can be used for both submerged and emerged environments. Its main advantage consists in enabling an a priori identification, on a single chart, of the main expected impacts induced by coastal defense structures on the protected environments. In this paper, we present the methodological approach developed in order to create the “impact vs habitats and species” matrix-system, with specific reference to the potential impacts expected on habitats and species of European interest.
Paganelli D., Nonnis O., Finoia M.G. and Gabellini M., 2013. The role of sediment characterization in environmental studies to assess the effect of relict sand dredging for beach nourishment: the example of offshore sand deposits in Lazio (Tyrrhenian Sea)
Beach nourishment with relict sands has been carried out for several years as a way to counter coastal erosion problems, and it has proven to be a successful beach protection method and one of the most important coastal management tools available. It is however known that relict sand dredging may have significant physical and biological effects on the marine environment, especially in highly biodiverse environments and sensitive habitats such as the Mediterranean marine and coastal system. Within this framework, the Regione Lazio (Italy) local Authority has financed and implemented some research projects aimed at identifying marine sand deposits along the Latium continental shelf. The research brought to the identification of five areas suitable for the exploitation of relict sands along the Tyrrhenian continental shelf. ISPRA was commissioned to carry out environmental characterization studies to evaluate the effects of dredging nourishment-aimed relict sand on the marine environment. This paper presents the results of the grain-size characterization study carried out in the areas identified as suitable for dredging of relict sands; the study allows the identification of the main sedimentological features of the investigated areas, providing some of the necessary information to assess the potential environmental effects of relict sand dredging.
Park, H.S., Hong, S.J. and Kim, D.S., 2013. Development of tsunami disaster response system using hazard mapping,
The purpose of this study is to develop the Tsunami Disaster Response System (TDRS) to reduce the damage caused by tsunami in the eastern coast of Korea. TDRS is constructed by using “hazard mapping techniques” along with several other methods. The highly populated and potentially dangerous areas of the eastern coast have been selected and a test is performed on forty-three different target regions to establish a tsunami disaster response system and hazard mapping. In addition, the existing tsunami response measures are analyzed including shelters, evacuation methods, and maps; and surveys are conducted to assess the climate, population and land-use of the selected regions. Topography and bathymetry data are also acquired and processed for numerical modeling, through which a total of forty-four hazard maps are prepared to estimate tsunami in four magnitudes (M7.5~M9.0) from eleven seismic zones for each study region. As a result, tsunami hazard maps are prepared on the eastern coast regions, which allows for a fast and accurate response to tsunami. Through this study, the study region for tsunami hazard mapping is selected, detailed topographical information and grid systems (4.5 m resolution) in the coastal zone are acquired, inundation characteristics are analyzed for each study region, and tsunami hazard maps are prepared for each study region. The “tsunami disaster response system” developed in this research will be employed as a comprehensive decision making system for tsunami; and will be utilized as a disaster prevention system to make an anticipative response against disasters by central and local governments; as well as a guide for evacuation and disaster management.
Pessoa, R.M.C., Pereira, L.C.C., Sousa, R.C., Magalhães, A., and da Costa, R.M., 2013. Recreational Carrying Capacity of an Amazon Macrotidal Beach During Vacation Periods.
Ajuruteua is one of the most popular beaches in the Brazilian state of Pará, and receives thousands of visitors during the peak summer months, primarily in July. The present study focused on the spatial and temporal patterns of use of Ajuruteua beach during the peak visitation period (July) and the rainy season (Easter holiday in April). The data were used to estimate the beach's recreational carrying capacity during the two seasons, as well as to formulate guidelines for future public policies related to local beach management. Larger numbers of beachgoers were recorded during the July sample, although substantial numbers were also observed during April, due to the low rainfall and high levels of sunshine during the specific period. During July, the peak visitation days were Saturday and Sunday. Peak visitation times were between 11:00 h and 12:00 h, and carrying capacity ranged from 6.0–1010.35 m2 per person in zone 1, 1.85–2575 m2 per person in zone 2, and 6.82–150 m2 per person in zone 3. In April, Friday and Saturday were the most popular days. Peak visitation times were between 12:00 h and 13:00 h, and carrying capacity was 7.07–72.17 m2 per person in zone 1, 53.91–436.67 m2 per person in zone 2, and 9.76–400 m2 per person in zone 3. Carrying capacity exceeded tolerable limits in July, and there is a clear need for the implementation of adequate coastal management strategies in order to improve local tourist facilities during peak vacation periods.
Luísa Schmidt, Ana Delicado, Carla Gomes, Paulo Granjo, Susana Guerreiro, Ana Horta, João Mourato, Pedro Prista, Tiago Saraiva, Mónica Truninger, Tim O'Riordan, Filipe Duarte Santos, Gil Penha-Lopes
Schmidt, L., Delicado, A., Gomes, C., Granjo P., Guerreiro, S., Horta, A., Mourato, J., Prista, P., Saraiva, T., Truninger, M., O'Riordan, T., Santos, F.D., and Penha-Lopes, G. 2013. Change in the way we live and plan the coast: stakeholders discussions on future scenarios and adaptation strategies
A scenario of increased risks due to climate change and coastal erosion, coupled with a stringent economic recession, is threatening the Portuguese coast. Three particular locations are the focus of CHANGE – Changing Coasts, Changing Climate, Changing Communities, a 3-year study (2010–2013) that aims to understand social perceptions about coastal risks and to examine new ways of adaptive management. The project involved assessing peoples' representations about the coastal present and possible coastal futures and discussed coastal change with local populations, in a country in which the protection of vulnerable coast to date has had little public involvement. The three coastal stretches studied face increasing coastal risks and the perspective of reduced public spending, fuelling uncertainty about their future. Public participation in coastal management has been almost entirely absent, which makes the social science based contribution of this research even more relevant. This research combines: a) scientific assessments on the past and future evolution of the shoreline, taking into account the impacts of climate change; b) interviews with policy-makers, coastal experts and stakeholders, as well as local public opinion surveys; c) the outputs of a model for coastal governance and community building, based on local discussions through focus groups and workshops. This paper is based on the surveys and focus groups undertaken in the case-study area most at risk from coastal change, Vagueira. We conclude that there is a growing perception of coastal threat and potential for the development of adaptive coastal management, taking advantage of local knowledge and initiative.
Silva, S.F. and Ferreira, J.C., 2013. Beach Carrying Capacity: The physical and social analysis at Costa de Caparica, Portugal
The bathing-tourism phenomenon on Costa de Caparica beaches has evolved into mass tourism, compromising environmental preservation and socioeconomic balance. The aim of the study focuses on the use of management tools, such as carrying capacity, expanding to associated surfing activity in the water, as surfers are also users. This tool operates in available surface area and utilization rates, and it is also strongly influenced by the interconnection of analysis methodologies under protection of areas of higher sensitivity, and within the recreational conflict and behavioral response of users. For physical carrying capacity a head-count of users (surfers and beachgoers) was made at two different Costa de Caparica beaches, assessing their spatial distribution. After that, conflicts were analysed and sand dunes' vulnerability were studied. Finally, through GIS, areas of use were delimited and by utilization rates the advisable maximum number of users for each area was obtained. Social carrying capacity was conducted through 322 personal interviews, looking at coastal perception and beach usage. The observations made during the summer months showed that user rates were 26m2 and 54m2 per use on the sand area and, 250m2 and 660m2 per user on the water plane for surfers. The comparison of physical and social carrying capacity showed an overcrowding phenomenon, which translated into a degree of discomfort for users, especially for surfers. This paper explores the physical dimension of the beaches and the perception of users, and the need to integrate the water plane as a part of the beach carrying capacity into the beach plans.
Choi K.H., Kim, Y.M., and Jung, P.M., 2013. Adverse effect of planting pine on coastal dunes, Korea.
Forestation on the coastal dunes has been regarded as one of the best programs that help to stabilize the dune landscapes and protect the residential area from strong winds, blown sands, and salt spray. Introducing exotic species for dune stabilization was very common in the past. However, it could deprive coastal land of its ability to naturally recover, causing a retreat of coastline as well. As a typhoon passed through the Korean Peninsula early September in 2010, coastal dunes along the west coast of the peninsula were severely damaged during the storm. Some dunes retreated landward more after erosion, while others recovered their original profile through aeolian transport processes mainly in winter season. Vegetated dunes with pine trees recovered relatively less after the erosion than grass-covered dunes. Planting pine trees may interfere in these interactions, weakening natural recuperative power. We compared the characteristics of wind environment, morphology, and vegetation between the grass-covered dunes and the dunes covered with pine trees, for the purpose of the effectiveness of planting trees on dunes. The pine forest decreases the wind velocity on the front side of the dune to less than 50% of the grass-covered dune. Especially, the velocity of the strong winds faster than 4.5 m/s diminished to 25% of the control sites, resulting in decreased blown sand supply. Flora is also changed in the forested area. Terrestrial plants have invaded after pines were planted. In contrast, natural flora gets disappeared after the introduction of alien and exotic species. This study suggests that planting tree is likely to lead negative impact on coastal dunes. It may result in a retreat of coastline, loss of land, and devastation of dune ecosystems.
Sousa, L.P., Lillebø A.I., Gooch G.D., Soares J.A., Alves F.L., 2013. Incorporation of Local Knowledge in the Identification of Ria de Aveiro Lagoon Ecosystem Services (Portugal).
Coastal lagoons, such as Ria de Aveiro, are of strategic importance as they play a crucial role in almost all biogeochemical processes that sustain the biosphere and provide a variety of services, which are essential to the human wellbeing. Due to their potential vulnerability, to the increased human-related activities and pressures, the management of these systems requires an integrated and ecosystem based approach with close engagement of civil society. It is in this context that this research aims to include the population knowledge in the identification of Ria de Aveiro ecosystem services. In the scope of the EU-FP7 LAGOONS project 9 Focus Groups with the coastal lagoon inhabitants have been developed, in order to combine different scientific disciplines with local knowledge and stakeholders' views. In these sessions the participants freely discussed the topic of ‘Ria de Aveiro', and identified the types of uses and activities, discussed the current management model, and presented some recommendations for the future. This paper uses this privileged contact and proximity with local population to analyse the ecosystem services that participants indirectly identified. Relevant examples are the use of the lagoon for recreation, fishing or education-research activities. In terms of results, participants mainly identified provisioning and cultural services; however, even indirectly, they show some concerns regarding regulation and support services. Participants recognized the dependency of their uses and activities to a healthy ecosystem. The incorporation of their knowledge and concerns in the Ria de Aveiro management strategies is very important, since it has a pedagogical role and if people identify themselves with the decisions, they will accept them and enforce the compliance by the various users of Ria.
Sousa, R.C., Pereira, L.C.C. and Costa, R.M., 2013. Water quality at touristic beaches on the Amazon coast.
The beaches of the Brazilian Amazon coast are visited by thousands of tourists each year, mainly during the peak summer vacation month of July. Unfortunately, the beaches have been developed without adequate planning and the lack of a public sanitation system results in frequent bacteriological contamination. Given this, the aim of the present study was to verify the bacteriological quality of the water (total coliforms) at three local touristic beaches over different stages of the tide cycle. The campaigns were conducted in July 2009 and 2010 at Ajuruteua, Atalaia, and Princesa beaches. Water samples were collected in the surf zone every 3 hours (7:00–19:00 h), over four days (Friday–Monday). Simultaneously, oceanographic instruments were placed in the surf zone to obtain hydrodynamic data (currents, tides, and waves). The high local hydrodynamic energy is the result of macrotides (> 4.0 m), moderate wave heights (Hs > 1 m), and currents with speeds of around 0.5 m/s. Atalaia has the highest density of bars and hotels, and also presented the highest proportion of contaminated samples (45% > 1100 MPN/100 ml). At Princesa and Ajuruteua beaches there is less urban development and a smaller number of potential sources of contamination (cesspits). Peaks of contamination were recorded during high and ebb tides, when the water level reached the cesspits, although there was a rapid turnover and bacteriological concentrations returned to tolerable levels during the other tidal phases. To improve the local water quality, sewage treatment plants are needed urgently at all three sites.
Văidianu, N., 2013. Fuzzy cognitive maps: diagnosis and scenarios for a better management process of visitors flows in Romanian Danube Delta Biosphere Reserve
The Danube Delta Biosphere Reserve (DDBR) is located on the Romanian Black Sea coast and covers a vast area characterized by a low population density and well-preserved ecosystems with considerable potential for tourism. The need for an integrated management for DDBR is not new. Since the 90's, Danube Delta was declared as Biosphere Reserve and the universal value of the reserve was recognized by the Man and Biosphere (MAB) Program of UNESCO. This study examines the perceptions of visitors in DDBR, with the aim of developing key concepts that will be used in future management and communication strategies regarding biodiversity conservation in the area. It is important to assess the implication level of several sectors to increase the efficiencies for sustainability and rehabilitation programs. A number of 20 visitors were interviewed during August 2012 in Sfântu Gheorghe village and qualitative data were obtained. The discussions revealed ideas and concepts trying to answer to the following questions: “Is Danube Delta Biosphere Reserve a tourist destination which fulfils your expectations?” “Which are the pros and cons of Danube Delta Biosphere Reserve management?” We used a Fuzzy Cognitive Mapping (FCM) approach and let stakeholders draw cause-effect networks. The identification of stakeholders' perceptions of the DDBR area allowed us to analyze the cognitive maps, which consist of variables, causal relationships among those variables and of strengths of the connections. Causal mapping contributes to the goal of using peoples' knowledge of ecosystems to improve understanding of socio-ecological systems. Lacks of coordination and effective policies between the governmental institutions and the different sectors of activities were also identified as common problems for both environmental and socio-economic aspects.
van Proosdij, D; Perrott, B and Carroll, K., 2013. Development and Application of a Geo-temporal Atlas for Climate Change Adaptation in Bay of Fundy Dykelands.
Globally, dykelands (former marsh areas protected by dykes) are of strategic importance for climate change adaptation. Many were originally designed to protect agricultural land, yet now protect valuable infrastructure. The purpose of this project was to develop a comprehensive digital atlas incorporating historical plans, shore protection, coastal geomorphology and LiDAR to serve as a basis for climate change adaptation planning in the Bay of Fundy. 110 paper plans were scanned, geo-referenced and features such as current and historical dykes, aboiteaux (tide gates), armouring, ditches, creeks, property boundaries, foreshore marsh, and geodetic elevations were digitized using ArcGIS. Attributes included age of structure, material, dimensions, and ownership. Dyke elevations were surveyed using an RTK GPS, and individual sections were identified as being vulnerable to storm surge and sea level rise. Erosion rates and width of foreshore marsh were calculated per dyke segment. At present, 55% of dykes within Nova Scotia are within 0.5 m of critical elevations established in the 1960s, 2% are more than 0.5 m below critical and all are below the predicted rates of SLR by 2055. There is also a strong relationship between the placement of armouring along the dyke toe and foreshore erosion. Conversely, timely placement of armouring along the foreshore marsh decreased rates of erosion. This was most effective in areas with the largest fetch; less effective where erosion was driven by tidal currents. All data were integrated into ArcReader for use by Agriculture personnel and have been essential for cost effective climate change adaptation planning including dyke topping, hazard mitigation and education.
Yoo, C.I., Roh, S.H., Ryu, C.R., 2013. Estimation of Critical Limits by Marine work types for the Construction of Seawall at Sinseondae in Busan, Korea
Weather and wave climate is an important factor for the calculation of workable days and operation hours of equipment for the construction of seawall. However, at present, the number of working days calculated is based on the results of Ro (1969) which are more than 40 years old. In addition, in recent years, the work environment has changed a lot because of state-of-the-art construction equipment and extreme weather conditions due to global warming. Therefore, it is necessary to recalculate workable days to estimate critical limits of marine construction. The purpose of this study is to analyze the critical limits of work types for the construction of seawall using daily field work sheets and the meteorological conditions at Sinseondae in Busan, Korea. Also, the measurements of damaged seawall by high waves and one small typhoon were carried out, and days spent on disaster recovery were recorded. Finally, the working hours for each kind of construction equipment at each stage were collected, and the utilization rate of the major equipments was calculated. The results of estimated weather conditions for workable days and non-workable days between September, 2006 and November, 2008 monthly average 26.1 and 4.3 days, respectively (as shown in the worksheet below). Moreover, workable and non-workable days compared with Ro (1969) are estimated to increase 129.1% and decrease 42.2%, respectively. The result clearly shows that workable days have increased by about 30% over the past 40 years. The duration of damaged seawall with reconstruction totals 62 days out of 317 workable days in 2007. As a matter of fact, it is reasonable to suppose that the purely monthly average of workable days of seawall construction is 20.1 days.
Zhang, X., Luo, J., Dong W. and Gao L., 2013. Exploring and visualizing three-dimensional ocean data in the China Digital Ocean Prototype System
Exploring and visualizing three-dimensional ocean data on visual globes is a new research domain necessary for the construction of the Digital Ocean and Digital Earth projects. In this paper, we report an effort to visualize and explore the ocean three-dimensionally for the China Digital Ocean Prototype System (CDOPS). This three-dimensional ocean environment is composed of three parts: the three-dimensional coast, the ocean surface and the three-dimensional ocean floor. In the study that follows, the in situ observational data were visualized by a two-dimensional graph. The remote sensing information product was overlaid on the globe in a distributed web environment, and the model output data were visualized and explored in a web environment with vertical profile and a seriate change-representation function. The applications of the CDOPS are introduced at the paper's end. This paper is based on an ongoing research project on the development of the CDOPS, a system that can facilitate the integration, sharing, visualization and usage of and access to ocean observation data and model computing data from the Digital Earth system.
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