BioOne.org will be down briefly for maintenance on 14 May 2025 between 18:00-22:00 Pacific Time US. We apologize for any inconvenience.
Registered users receive a variety of benefits including the ability to customize email alerts, create favorite journals list, and save searches.
Please note that a BioOne web account does not automatically grant access to full-text content. An institutional or society member subscription is required to view non-Open Access content.
Contact helpdesk@bioone.org with any questions.
Díaz-Sánchez, R., López-Gutiérrez, J.S., Lechuga, A., Negro, V., 2013. Runup variability due to time dependency and stochasticity in beach profiles. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings of the 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 001-006, ISSN 0749-0208.
Equations for extreme runup worked out from several experimental studies are compared. Infragraviatory oscillations dominate the swash in a dissipative state but not in intermediate reflective states. Therefore two kinds of equation depending on either significant wave height, H0, or the Iribarren number, ξ0, should be used. Through a sand bed physical model with a uniform sand bed slope, equations are proposed for both beach states, and results are compared with precedent field and physical model experiments. Once the equations are chosen, the time-longshore variability in a medium long term time scale of the foreshore slope is evaluated in two extreme cases relating to the Spanish coast. The Salinas beach on the North coast (Bay of Biscay) displayed a permanent dissipative beach state with small variations in the beach foreshore slope both along the shore and in time, so foreshore slope deviations in a medium-long term period were irrelevant and extreme runup is predicted with the wave height worked out from the design return period. Peñíscola beach on the East coast (Mediterranean sea) displayed an intermediate state. If only time variations are analysed, variations in determining extreme runup are irrelevant. In contrast, significant differences were found when the longshore variations were studied in this Mediterranean beach.
Burningham, H., French, J.R., 2014. Travelling forelands: complexities in drift and migration patterns. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 102–108, ISSN 0749-0208.
Cuspate forelands have been described from a range of shorelines around the world, but in the majority of cases, the foreland maintains a constant position relative to the neighbouring shoreline. Here, we describe the contemporary geomorphology and historical evolution of a small cuspate foreland on the Suffolk coast, UK, which has been migrating northward for several centuries. Benacre Ness, a mixed sand and gravel sedimentary accumulation, is currently located at Kessingland, 5 km to the north of Benacre, from which it gained its name when adjacent to it in the 19th century. The foreland was previously called Covehithe Ness, having been adjacent to Covehithe (3 km south of Benacre) early in the 19th century. Previous sediment transport experiments and modelling studies have demonstrated a net southerly transport direction on this coastline, yet the foreland has continued to migrate northward over several centuries. Local reversals in sediment transport direction and rates are likely responsible for the northward migration of the foreland, but substantial changes in behaviour over the last 400 years suggest a close relationship between foreland dynamics and coastal configuration.
Chaumillon E., Ozenne F., Bertin X., Long N., Ganthy F., 2014. Wave climateand inlet channel meander bend control spit breaching and migration of a new inlet: La Coubre Sandspit, France. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 109–114, ISSN 0749-0208.
This study focuses on the mid-term (infra annual and pluri annual; over the period 1999–2013) morphological evolutions of a sandspit (La Coubre Sandspit, West coast of France), with a particular emphasis on spit breaching, new inlet opening and migration. Morphological evolutions are observed from a large number of aerial photographs and satellite images and are compared with wave parameters and extreme events (periods where significant wave height exceeds the 1% largest waves with water level exceeding the 90% highest water level) obtained from a high resolution hindcast wave modelling. It appears that extreme events are likely to be responsible for spit breaching and new inlet opening. Once opened, the new inlet migrates downdrift, but its migration rate is not correlated with the wave climate variations. Detailed geomorphological observations suggest that the main control on downdrift inlet migration is related to orientation of the meander bend of the tidal inlet main channel. When the meander bend is convex in an updrift direction, it counteracts the littoral drift and slows the inlet migration. Oppositely, when the meander bend is convex in a downdrift direction, the meander-induced transport is in the same direction as wave-induced longshore transport, which allows the inlet to migrate much faster.
Duce, S., Vila-Concejo, A., Hamylton, S., Bruce, E., Webster, J. M, 2014. Spur and groove distribution, morphology and relationship to relative wave exposure, Southern Great Barrier Reef, Australia. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 115–120, ISSN 0749-0208.
Spur and groove features occur on the seaward reef slope of coral reefs around the world. They are believed to act as important natural breakwaters, regulating the hydrodynamic energy and nutrients received by reef platforms. They also represent one of the most diverse and productive zones of modern reefs. However, the formation processes and morphodynamics of spur and groove systems are poorly understood, particularly in the Great Barrier Reef (GBR). This paper constitutes the first broad scale analysis of spur and groove systems in the Capricorn Bunker Group (CBG) in the southern GBR. It uses remotely sensed imagery coupled with ground-truthed data to measure groove length at four reefs (Wreck, Heron, One Tree and Lady Elliot). A total of 2621 grooves were digitised across the four study reefs. Groove length was found to vary both between and within the study reefs. The maximum groove length was 536 m. Average groove length ranged from 93 m at Wreck Reef to 32 m at Heron Reef. This data was compared to relative wave exposure estimates derived from the fetch scenario at each reef. Strong positive correlation was found with groove length increasing as wave exposure increased. Groove length was highly spatially dependant and varied around the reef platforms according to the degree of wave exposure. The longest grooves were found on the most exposed, eastern sides of all reefs. These results provide valuable insight into spur and groove function, formation and likely response to future environmental changes in the CBG and further afield.
Matutano, C., Negro, V., López-Gutiérrez, J. S., Esteban, M.D., Hernández, A,. 2014. The effect of scour protections in offshore wind farms. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 012–017 ISSN 0749-0208.
The installation of offshore scour protection systems in offshore wind farms allows avoid the effect of scour phenomenon around these structures. Up to date, numerous research projects have been carried out to justify the necessity of the scour protection systems and also to optimize their design. Protection systems based on riprap is frequently used due to its low cost and easy availability compared to other solutions such as geotextile bags or prefabricated concrete blocks. The sizing of these structures can be performed according to a series of recommendations that can optimize the costs associated with them, but there have been only few studies with real data up to now which have allowed identify the need for such protections.
This investigation aims to assess the functionality of the scour protections adopted through the available data about their characteristics and the scour depth developed around the foundations. In this sense, this paper presents the results of a study that analyzes the functionality of scour protections in different European offshore wind farms.
Knight, J., Burningham, H., 2014. A paraglacial coastal gravel structure: Connell's Bank, NW Ireland. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 121–126, ISSN 0749-0208.
Coastal gravel structures have been well documented worldwide and are formed dominantly by onshore wave transport of gravel, mainly during storm events. They are commonly observed along paraglacial coastlines where their origins are more ambiguous because of the effects of antecedent patterns of sediment supply, glacioisostatic sea-level change, and contemporary coastal processes. This paper describes the properties and polygenic origin of Connell's Bank, a small paraglacial gravel structure on the Atlantic-facing coast of NW Ireland. This feature has been shown on historical maps, air photos and satellite imagery since ca. 1850 but its outline has varied depending on seasonal migration, expansion and contraction of a sand veneer. It has also acted as a major control on tidal channel position within the estuary, and thus on sensitivity of the estuary system to ocean forcing. In detail, the bank surface is composed of cobbles sourced from outside of the immediate catchment. These surface cobbles are strongly winnowed, forming a lag deposit, whereas below the surface, cobbles exist within a granule and shell matrix. A significant proportion of surface cobbles show evidence for recent ventifaction by blown sand at low tide. The paraglacial evolution of Connell's Bank since the last glaciation comprises the following stages: (1) deposition of coarse glacigenic sediment as a moraine or proximal outwash fan during the late Pleistocene lowstand; (2) reworking of sediments onshore during early Holocene sea-level rise; (3) surface winnowing during mid to late Holocene tides and storms; and (4) surface cobble modification by contemporary wind abrasion.
Huisman, B.J.A., Sirks, E.E., van der Valk, L., Walstra, D.J.R., 2014. Time and spatial variability of sediment gradingin the surfzone of a large scale nourishment. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 127–132–134, ISSN 0749-0208.
Temporal and spatial variations in sediment gradation in the surfzone were investigated for a large scale nourishment (Sand Motor) at the Dutch coast (~ 21.5 million m3 sand). This nourishment provides an excellent opportunity to investigate the effect of hydrodynamic conditions on the spatial and temporal development of sediment grading. A strong point of the Sand Motor is that it has a well-known initial sediment composition. Measurements of the sediment grading at the Sand Motor were carried out during and after its construction to investigate the sorting process. Samples were taken for six cross-shore rays at ten depth contours (from MSL -1m to MSL -10m). A weighted average of the grain size distribution was determined for each cross-shore transect to investigate the alongshore sorting process. Similarly, cross-shore averaged sediment properties were determined for the samples above and below MSL -4m to assess the cross-shore sorting process. The sieved samples showed that: (1) significant sediment sorting takes place across the surfzone of the Sand Motor. Typically, the sediment in the surfzone of the exposed part of the Sand Motor is 20 to 30% coarser than the average for the survey; (2) a large depositional area with relatively fine material (150 to 200 μm) from the Sand Motor has developed on the Northern side of the Sand Motor; and (3) an alongshore band with finer sediment was found at water depths of 4 to 6 meter below MSL as a result of selection processes at the waterline.
Min, J. E., Choi, J. K., Yang, H., Lee, S., Ryu, J. H. 2014. Monitoring changes in suspended sediment concentration on the southwestern coast of Korea. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 133–138, ISSN 0749-0208.
Concentrations and distribution patterns of suspended sediment (SS) are key indicators of marine environmental change, particularly in coastal areas, which gives good information on the deposition and migration of sediments from land. In this study we analyzed 632 scenes (79 days × 8 scenes) of Geostationary Ocean Color Imager (GOCI) data in order to investigate SS variations relating to tides, tidal currents, bottom morphology, river discharge, and so on. We also compared them to the numerical model of tidal currents for the Yellow Sea. The study area, the coastline of Mokpo, is characterized by shallow water depths (<50 m), a relatively large tidal range (8 m) and by strong tidal currents (1 to 2 m/s). The coastal area of Mokpo shows extremely high SS concentrations (SSC) caused by a resuspension of bottom sediments. GOCI, the world's first geostationary ocean color observation satellite, can obtain data hourly during daylight. Therefore, GOCI is well equipped for the detailed analysis of time-series variations in SSC with regard to tides and tidal currents along Mokpo. The concentrations and distribution patterns of SS in the study area were mainly affected by tidal currents. During flood tide, SSC showed higher values than during ebb tide, and the SS distribution pattern flowed in a northerly direction. On the other hand, during ebb tide, the SS distribution pattern flowed towards the south. Bottom morphology also displayed a similar pattern to the SS distribution.
Ratas, U., Rivis, R., Kont, A., Tõnisson, H., Vilumaa, K., Anderson, A., Szava-Kovats, R.,2014. Regional variation in the dynamics of Estonia's coastal landscapes. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 139–144, ISSN 0749-0208.
The coastal landscapes of Estonia are young (less than 10,000 years old). Their development is affected by the Baltic Sea, by pre-existing geomorphology and by regional tectonic uplift. Since emerging from the sea ~5,000 years ago, the coastal landscapes have been evolving under regressive sea conditions. The landscape diversity is greatest on coasts with variable topographies and those exposed to wind and waves. Low and flat parts of the coast, which are seasonally inundated, exhibit less variable landscapes. Landscape changes in coastal areas no longer affected directly by the sea have been caused largely by human activity. Abrupt socio-political and economic changes over the last century led to a cessation of traditional land use during the Soviet era with urban sprawl and expansion of recreation areas after re-independence in the beginning of the 1990s. The aim of this paper is to analyze the structure, formation conditions, and the velocity and extent of change in coastal landscapes (for both natural and human-induced impacts) along different coastal regions of Estonia. The Estonian coast can be divided into four distinct regions: 1) Gulf of Finland; 2) Baltic Proper; 3) Gulf of Livonia and 4) Coast of Väinameri, making it possible to compare the influence of sea exposure, geological structure, vegetation, soil productivity, age of human settlements and character of land use on the development of coastal landscapes. The results of the current study are applicable to coastal conservation, to the development of sustainable coastal land use and to the facilitation of transnational tourism.
Schwarzer, K., Bohling, B., Heinrich, C., 2014. Submarine hard-bottom substrates in the western Baltic Sea–human impact versus natural development. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium(Durban, South Africa),Journal of Coastal Research, Special Issue No. 70, pp. 145–150, ISSN 0749-0208.
Large areas of the seafloor in the western Baltic Sea are covered by lag deposits of Pleistocene origin, consisting of gravel, stones and boulders. From about 1800–1974, commercial extraction of stones and boulders from these shallow submarine areas was carried out. These activities have fundamentally changed the sediment distribution patterns and ecological conditions of the seafloor. Based on comparisons between old analogue and modern digital sidescan sonar images and direct abrasion measurements on the seafloor by scuba divers, the development of this hard-bottom substrate was studied on a decadal to seasonal scale. We show that due to abrasion processes the amount of boulders has been increased over a 22 year period. Thus, natural regeneration of hard-bottom substrate and improvement of the ecological status of the shallow marine environment is possible. This needs to be considered in order to reestablish a “good ecological status” as demanded by administrative guidelines like the EU Water Framework Directive and the Marine Strategy Framework Directive.
Smith, A.M., Guastella, L.A., Goble, B.J., 2014. Forecasting lagoon outlet erosion: KwaZulu-Natal, southeast Africa. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 151–156, ISSN 0749-0208.
The Amanzimtoti Lagoon is at the mouth of the Amanzimtoti River. The lagoon outlet changes systematically in response to the 18 year long Dyer-Tyson summer rainfall cycle (DTC). During the dry part of the DTC the lagoon is generally closed, opening only during heavy rainstorms. When closed the lagoon is separated from the sea by a baymouth bar, varying from 30 to 60 m wide. The open-days per year have increased dramatically as the DTC has entered the wet phase. Early in the DTC the lagoon rarely opened, and when this occurred it breached near the centre of the headland bound bay, but as the DTC-driven runoff cycle has progressed the outlet has remained open. However, during this open phase the outlet has been forced southward along the back beach until it deflected seaward by the southern headland outcrop. This appears to be brought about by longshore drift and an increased beach width. We suggest that this is due to the shoreward reworking of sediment by waves. This sediment has been brought down by the river in increasing amounts as the wet part of the DTC waxes, strengthening the seasonal rainfall and the river flow cycle. Wave reworking has forced the outlet along the back beach causing erosion of the coastal dune behind the back beach. Thus, the lagoon mouth enters a predictable erosion phase as the DTC progresses. This cyclicity can be used to forecast this type of lagoon outlet erosion. The Amanzimtoti Lagoon has strong similarities to the Hapua Lagoon-type recognized from New Zealand.
Kang, J., Woo, H.J., Lee, Y.-K., Son, Y.B., 2014. Seasonal sedimentary processes of the macrotidal flat in Gomso Bay, Korea. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 157–163, ISSN 0749-0208.
To understand seasonal sedimentary processes, we analyzed sediment grain size, short-term sedimentation rates, and chemical tracers to determine sediment provenance in the Gomso tidal flat, which is located on the western coast of Korea. It is a funnel-shaped embayment with a mean tidal range of 4.3 m. Calculating the elevation from a digital elevation model (DEM), the landward inner bay was relatively higher than that of the outer bay. Sandy sediments generally dominated the outer bay, whereas sandy mud sediments were distributed in the inner bay. The middle bay consisted of muddy sand sediments. From February 2011 to February 2012, the net deposition rate in the inner tidal flat of the bay was 41 mm/year. Erosion dominated the middle and outer tidal flats of the bay, with net erosion rates of −30 and −10 mm/year, respectively. Seasonal variations in sedimentation in the Gomso tidal flats occurred with deposition via the inflow of fine-grained sediments during spring and summer and winnowing from the bay during autumn and winter. The rare earth element (REE) analysis proved that the fine-grained sediments were transported from Jujin Stream in the southern bay and deposited on the middle bay tidal flats, especially during the rainy season. The source of the outer bay sediments was related to the inflow of fine sediments of alluvial origin. Therefore, the major forcing factors affecting the seasonal variation in sedimentation involve a combination of tidal currents and waves, together with heavy rainfall.
Jarmalavičius, D., Pupienis, D., Žilinskas, G., 2014. Sea level fluctuation and shoreline evolution on decadal time scale, Lithuanian Baltic Sea coast. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 164–169, ISSN 0749-0208.
Fluctuations in sea level are reflected in shoreline dynamics. Depending on the nature of the change, the coast is dominated by either erosion or accumulation processes. However, despite considerable attention to this subject, few works have been dedicated to the direct research of coastal development dependence on these determining factors. The objective of this paper was to assess the impact of sea level fluctuations on shoreline dynamics based on coastal monitoring data. The monitoring of coastal dynamics has been carried out since 2002. Annual shoreline displacement was determined based on the obtained data. In addition to morphometric data, sea level data from the Klaip da gauge station from 2002–2012 were used. The results showed that the long-term tendency of shoreline displacement was not uniform. From 2002–2012, a shoreline recession of the mainland coast was observed, whereas accumulation processes prevailed in the Curonian Spit. Also, a trend of rising sea level was observed from 2002–2012. No significant correlation between shoreline displacement and sea level on a decadal time scale was found. This may be due to the fact that the long-term trend in sea level was negligible and had no distinct impact on coastal dynamics. Short-term changes in sea level, on the other hand, have had a greater impact on coastal dynamics. A good correlation between the short-term change in yearly sea-level and shoreline displacement was observed.
Silva, A.L.C., Silva, M.A.M., Souza, R.S., Pinto, M.L.V., 2014. The role of beachrocks on the evolution of the Holocene barrier systems in Rio de Janeiro, southeastern Brazil. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 170–175, ISSN 0749-0208.
Beachrocks at different locations along Rio de Janeiro coast (southeastern Brazil) play an important role in the understanding of coastal evolution and sea-level fluctuations in the Holocene. The studied area presents a long and wide stretch of coastal plain characterized by two sandy barriers, which confine a series of small isolated chain-like lagoons in addition to large lagoons on the reverse side of the inner barrier. The beachrocks occur at different positions in relation to present-day mean sea level. These can be observed as submarine outcrops and along the beaches. The 8.100 years old B.P. beachrocks reveal a phase of retrogradation of the barrier system, and the drowning and partial preservation of this barrier during the sea transgression through the Holocene. The beachrocks are composed of medium-to coarse sand grained bioclastic quartz-rich sandstones which are strongly cemented by calcite. Three successive events of calcite cementation have drastically reduced the porosity of the rock. Calcite cement occurs as three basic forms: isophacous fringe of very fine crystalline calcite, aphanocrystalline calcite and coarsely crystalline calcite. Each textural type indicates different geochemical composition of the pore waters during the very early diagenetic evolution within the intertidal zone of the coastal barrier system.
Jeanson, M., Anthony, E.J., Etienne, S., Dolique, F., 2014. Morphodynamic characterization of beaches on a Pacific atoll island: Tetiaroa, French Polynesia. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 176–181, ISSN 0749-0208.
Beach profile types and wave characteristics were monitored in April 2013 on the small islet of Onetahi in the south Pacific coral reef atoll of Tetiaroa, French Polynesia, with the aim of characterizing atoll islet beach morphodynamics. Twelve beach profiles were each surveyed using a theodolite, and water levels and wave characteristics measured over four semi-diurnal tidal cycles using four miniature pressure sensors deployed in the subtidal zone. Water levels corresponded to a very narrow microtidal range (~0.2 m). Wave heights were extremely low throughout (<0.15 m), and spectral decomposition showed a mix between gravity and infragravity energy. The latter dominant at high water, whereas energy was virtually nil at low tide. The wave characteristics, which reflect significant filtering of large Pacific waves by the atoll reef, were not in phase with the intertidal beach morphology. These were interpreted as largely inherited from differential exposure to higher-energy events that occasionally impacted the atoll, notably Cyclone Oli in February 2010. Sand aprons in the lagoon, moving from the eastern to the southern and ultimately the western shores of the island in response to wave pumping, locally enhance build-up of the lower beach where shoreline orientation changes. Confrontation of these observations with long-term islet shoreline trends identified by Le Cozannet et al. (2013) suggests that high-energy event-scale changes and daily background beach cosmetic changes associated with subtidal sand apron mobility, and intertidal swash reworking during the narrow tidal excursion are embedded in long-term morphological stability likely hinged on sand circulation around the islet.
Williams, J.J., Esteves, L.S., Conduche, T., Barber, P., Tindle, A., 2014. Using Combined Modelling Approaches to Improve Coastal Defence Design: a case study at Hopton, UK. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 018–022, ISSN 0749-0208.
A storm that occurred close to the spring tidal maxima in March 2013 resulted in beach lowering and cliff recession of c. 5 m along a 110 m frontage at Hopton-on-Sea, UK and threatened the static caravan park of Bourne Leisure Ltd. This paper reports a study using XBeach and MIKE21 models to assist with the design of new coastal defences to reduce cliff and beach erosion. Two schemes are examined here: three fishtail rock groynes (Scheme 1); and ten ‘double-head’ curved rock groynes (Scheme 2). The selected design must provide acceptable level of protection and, to be granted consent, no adverse environmental impact must be demonstrated. Current practice using a single numerical model can provide a cost-effective tool for coastal defence assessments. However, the work presented here show that when good agreement between complementary models can be demonstrated, greater confidence can be given to model results. Specifically, refinements to the present scheme design were made possible by the use of the XBeach model, which allowed identification of the cross-shore limits of sediment transport in storm conditions, and by the MIKE21 model which allowed quantification of alongshore scheme impacts. Together, the model results have assisted the development of an improved final scheme design which minimizes potential environmental impacts.
Meirelles, S., Horner-Devine, A.R., Henriquez, M., Stive, M., Pietrzak, J., Souza, A.J., 2014. Middle shoreface sand transport under stratified regimes. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 182–186, ISSN 0749-0208.
Observations from a field experiment along the south-Holland coast, the Netherlands, were carried out in order to obtain new insights about the impacts of the Rhine ROFI (Region of Freshwater Influence) on the sand transport patterns. The net alongshore sand transport is generally governed by tides. The sediment concentration in the middle shoreface increased significantly with approaching waves of higher than ~1 m and Tm0 > 5 s. The southward net transport of the alongshore component does not agree with the literature. Modulations of the net cross-shore transport direction were observed. The net transport is more relevant during the neap tides where the velocity magnitudes are smaller.
Miles, J., Thorpe, A., Russell, P., Masselink, G., 2014. Megaripple dynamics on a dissipative sandy beach. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 187–192, ISSN 0749-0208.
Conventional force models of bedform dimensions link bedform wavelength and height to wave orbital excursion and wave orbital velocity. Self-organization models, however, suggest that bedform wavelengths either: grow, remain stable, or are wiped flat, but are unable to reduce in length. This paper presents measurements of megaripple evolution on a macrotidal sandy dissipative beach at Perranporth, England, using measurements from a Sand Ripple Profiler. Measurements were made as the tide flooded and ebbed over the instruments, producing a cross-section of the moving surf zone for 12 separate tides. Water depths varied from 1 to 6 m, and wave heights were up to 2.2 m. The data allowed megaripple dimensions to be observed with heights up to 30 cm and wavelengths up to 1.8 m. Megaripples were observed to grow and decay in both length and height. Megaripple spacing did not increase consistently with age of ripple. Megaripple lengths changed at rates of up to 5 cm/minute, and height changed at rates of up to 0.5 cm/minute. Maximum changes took place in large orbital velocity conditions. At orbital velocities > 0.5 m/s, ripples attempted to stabilize at a wavelength related to the orbital excursion, suggesting a forced mode. The most stable ripples had the greatest height and steepness. At orbital velocities < 0.5 m/s the spacing was greater than the orbital excursion, suggesting self-organized growth may be a more appropriate model for small orbital velocities.
Puig, M., Del Río, L., Plomaritis, T.A., Benavente, J., 2014. Influence of storms on coastal retreat in SW Spain. Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 193–198, ISSN 0749-0208.
Natural and anthropogenic controls contribute to coastal change at diverse temporal and spatial scales. This study presents an analysis of storminess and a correlation with the medium-term shoreline erosion rates in two sand spits of the Gulf of Cadiz (SW Spain). Recession rates were assessed by means of aerial photographs and orthophotographs considering the dune foot as an appropriate proxy. Storm events were obtained from a combination of coastal wave buoy data and the hindcast database of the HIPOCAS project. The characteristics of the storms were compared with shoreline changes determined using the aerial photographs, and the correlation between them was estimated and discussed. The best agreement between storms and shoreline change was observed in section 1 of Sancti Petri sand spit, while Valdelagrana sand spit showed a lower dependence between shoreline erosion and storminess. This is related to the contrasting exposure of both sites, with Sancti Petri being more exposed and thus more sensitive to storm impact. It is suggested that the main causes of retreat in Valdelagrana are human interventions performed on the coast and in the nearby rivers (breakwaters, jetties and dams). Nevertheless, storminess contributes to modulate recession rate, so that erosion rates increase when the number of storms is higher.
Randazzo, G., Cigala, C., Crupi, A., Lanza, S., 2014. The natural causes of shoreline evolution of Capo Peloro, the northernmost point of Sicily (Italy). In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 199–204, ISSN 0749-0208.
During recent times, the world's coastline has been constantly changing, and factors such as: the absence of sediment transport from rivers, urbanization of the coastal zone, construction of protective structures and ports, contribute to such change. An increase in frequency and intensity of storm events may also play a role. In the area of Capo Peloro (eastern Sicily) in the last 180 years, the changing coastline has been assessed using maps, aerial photographs, urban plans, historical notes, and surveys from 1824 to 2013 with the support of a long winded dataset series (1951 to 2012). The area of Capo Peloro is the northernmost headland of Sicily, dividing the Tyrrhenian from the Ionian Sea and stretching into the Strait of Messina. The four beaches which constitute the continuous coastal system of the cape show rapid evolution. Analysis of the wind records shows a decreasing trend for winds coming from the orientation range of 290°–330°, while there is an increasing trend for those coming from the range of 331°–20° and, in general, wind intensity has increased in the last 9 years. Comparison of the coastal evolution pattern and the wind data set, a direct relationship has been recognized, while urbanization has not affected this trend.
The beach of Tiro a Volo lost its capability to regenerate and protect itself naturally in 2012, which was the windiest year of the series considered. Erosion in 2012 uncovered old anthropic structures, eliminating the morphological connection between the beach and the alluvial plain. The hardening of the landward limit of the beach caused a loss of beach resilience. Due to the exposed structures, an artificial redistribution of the sedimentary material in the area is now necessary.
Biancini da Silva, A., Barboza, E.G., Rosa, M.L.C.C., Dillenburg, S.R., 2014. Meandering Fluvial System Influencing the Evolution of a Holocene Regressive Barrier in Southern Brazil. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 205–210, ISSN 0749-0208.
A meandering fluvial system changes its course according to geological time, eroding rocks and pre-existing deposits and transporting large volumes of sediment to the coastal plains. Understanding the evolution of channels and paleochannels in regions showing coastal barriers and relating them to changes in sea level becomes extremely important to comprehend the factors that contribute to the behavior of coastal barriers. During the Holocene the barrier at Passo de Torres located northeast of the Mampituba River, along the southern coast of Santa Catarina state, prograded approximately 5.5 km. The barrier comprises both foredune ridges, which occur in the landward portion, and transgressive dune ridges, which occur seawards. One feature that stands out in the region is that the regressive barrier morphologies are truncated (eroded) by paleochannels and channels of a meandering fluvial system, which can be related to the dynamics of the Mampituba River. These paleochannels have elongated morphologies with SW – NE orientation and are up to 25 km long. With the purpose of characterizing the longer paleochannels, the geophysical method of ground penetrating radar (GPR) was used, associated with drill hole and radiocarbon dating. The GPR profile reveals continuous reflectors (± 5 m depth) with great contrast and lateral continuity for over 450 m. These represent an erosive surface, interpreted as the base of the fluvial channel. The granulometric results indicate that around 5 m, an increase in grain size (fine sand grading to medium sand) and the presence of several shells. These are very fragmented, characterizing a probable bedload transport. However, shells of the genus Donax sp. were collected intact with no signs of abrasion. This genus inhabits beach environments (specifically foreshore) and cannot survive in freshwater environments. These shells were incorporated to the bedload of the fluvial channel through an inlet, probably during storm surge events. These events carried beach sands, associated with shells (mainly Donax sp.), towards the continent, which were incorporated into the fluvial sediments. The dating of these species revealed an age between 5.6 – 5.4 cal ka. The ages obtained are consistent with the maximum sea level of the Postglacial Marine Transgression (PMT) in southern Brazil. Because these shells are exclusive to beach environments, dating allowed us to infer that this channel was active and had connection with the ocean at about 5.5 ka, concomitant with the maximum sea level of PMT.
Bugajny, N. and Furmańczyk, K., 2014. Dune coast changes caused by weak storm events in Miedzywodzie, Poland In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 211–216, ISSN 0749-0208.
This paper describes the impact of weak storm events on morphological changes of the sandy, non-tidal Southern Baltic coast. It was initially assumed that weak storms do not cause any significant changes on the coast, i.e. dune erosion. For this purpose, 14 RTK-GPS surveys were carried out during June to December 2012, consisting of a cross-shore profile every 100 m along a 2 km stretch of coast. Offshore wave data (WAM model) and water level data (tide gauge) were also collected. The hydrodynamic conditions were grouped into 3 groups by Ward's hierarchical cluster analysis to investigate relationships with morphological changes on the coast. Correlation between volume changes and shoreline displacement for profiles and each group of hydrodynamic conditions were obtained. The correlation coefficient value for profiles ranged from R=0.41–0.91; and for groups R=0.79–0.82. It was found that for the first group (Hs<1 m), accumulation was observed almost in the whole area. For the second hydrodynamic group, some profiles accumulated while others experienced erosion. For the last group, erosion processes were dominant. The study reveals the oscillating nature of the coast within the study area. Volumetric changes between the first and last survey ranged from 0.8 m3/m to approximately −1.2 m3/m and the shoreline changed from rough to smooth.
Simeone, S., De Falco, G., Quattrocchi, G., Cucco, A. 2014. Morphological changes of an Mediterranean beach over one year (San Giovanni Sinis, western Mediterranean).In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 217–222, ISSN 0749-0208.
Mediterranean beaches experience major modifications in their morphology and grain size features mainly during intense storms and extreme meteo-marine events. The assessment of beach response to storms can be useful in the evaluation of coastal hazards, and in relation to the efficiency of management projects such as artificial nourishment. This paper aims to establish the subaerial morphological response of a beach located in western Sardinia (western Mediterranean) during the period of a year. Both experimental and numerical approaches were adopted to investigate the beach system. In particular, beach profiles, acquired by means of Differential Positioning System were used to analyze the morphological changes of the beach and wave parameters and current velocity data were collected by means of an Acoustic wave and current meter (ADCP). Numerical techniques were also applied to investigate the hydrodynamics in the area of study. Coupled wind wave - 3D hydrodynamic finite element model were used to reproduce the wave propagation and the wind, tide and wave induced 3D water circulation along the coastal areas, and it displayed a good accuracy. During the year, the beach experienced intense morphological changes in the area where submerged beach is not occupied by rocky outcrops and the model was also able to reproduce the related observed periods of strong wind wave events. The interdisciplinary approach allowed an evaluation to be made about the response of the beach morphology in respect to meteo-marine forcings.
Suursaar, Ü., Alari, V., Tõnisson, H., 2014. Multi-scale analysis of wave conditions and coastal changes in the northeastern Baltic Sea. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 223–228, ISSN 0749-0208.
Temporal variations of shoreline changes have been analyzed and interpreted in three differently exposed Estonian coastal sections. Using coastline contours that have been recorded frequently over the last twelve years, as well as recently digitized aerial photographs, orthophotos and old topographic maps (some of them dating back to 1900), all overlaid in the Mapinfo software, areal changes over different sub-periods were calculated. To explain the shoreline changes, two different wave modelling approaches were used and mutually compared. Both the BaltAn65 reanalysis (an ERA-40 refinement) forced SWAN model hindcast (1965–2005) and the point model runs (1966–2012), locally and independently calibrated against extensive wave measurements in these coastal study sites, confirmed specifically higher (and increasing) intensity of coastal processes in the westerly exposed study sites, and a decrease in northerly exposed sites. Some common quasi-periodic cycles with high stage approximately in 1985–1995, and probably also from 2007 can be found. However, the role of a few randomly occurring extreme winter storms (such as in 1967, 2005, 2007 and 2012) was often decisive within the sub-periods.
Hannes Tõnisson, Ülo Suursaar, Are Kont, Kaarel Orviku, Reimo Rivis, Robert Szava-Kovats, Kadri Vilumaa, Triin Aarna, Maris Eelsalu, Katri Pindsoo, Valdeko Palginõmm, Urve Ratas
Tõnisson, H., Suursaar, Ü., Kont, A., Orviku, K., Rivis, R., Szava-Kovats, R. Vilumaa, K., Aarna, T., Eelsalu, M., Pindsoo, K., Palginõmm, V., Ratas, U. 2014. Field experiments with different fractions of painted sediments for studying material transport in three coastal study sites in Estonia. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 229–234, ISSN 0749-0208.
Our current understanding of the morphodynamics in swash and surf zones is limited due to their turbulent and irregular nature. The importance of this zone to sediment transport led us to perform a sophisticated field experiment using painted sediments. Sediments collected locally from beach ridges were sorted into the following diameters: 1–2 5 cm, 2.5–5 cm and 5–10 cm. The sediments were painted, amassed in piles and placed at 0.5–10 m depths in three sites near the Estonian coast. The locations were recorded with GPS devices and photographed. The sediment piles placed in the sea were monitored at least once after an intense storm or once before and after the storm season. Some sediments were placed on the shoreline and monitored daily for a shorter period. Hydrodynamic parameters were also measured or hindcasted during the experiment. We found that wave breaking during storms can take place even at 6 m depth, but mostly between 2–4 m depth. Sediment fractions between 1–10 cm diameters can be transported over 20 m towards the shore. Even sediment piles at 10 m depth were moved 2–4 m, but towards the open sea. Sediments accumulated on the shoreline moved up to 3 m/hour along the shore and approximately 350 m during three months. We also found that calm periods can be more influential in places where regular vessel-generated waves wash the shores. As vessel-generated waves often approach from a different angle than natural waves, they can cause notable erosion during the periods when natural waves are weak or absent.
Larnier, S., Almar, R., Cienfuegos, R., Lejay, A., 2014. On the use of the Radon transform to estimate longshore currents from video imagery. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 023–028, ISSN 0749-0208.
In nearshore applications, the estimation of longshore currents is of primary importance since it controls the alongshore sediment transport and coastal evolution. Direct estimation of longshore currents using in-situ instruments is difficult and costly, especially under highly energetic wave climates. Low cost remote sensing systems based on video observations constitute a promising alternative when the drifting sea foam left after the passage of breaking waves is visible. In this paper we describe a method based on longshore timestacks that necessitates less data than approaches using the full video frames. Our approach uses the Radon transform applied on the time series derived from timestacks to produce an estimate of the longshore component of nearshore surface currents detected from the foam signature in video images. The Radon transform can be used to separate the wave crests from the drifting foam part. The identification of the longshore drift is enhanced with both a temporal and a spatial filters. The corresponding sinogram from the Radon transform is computed in order to find the angle of the alongshore drifting that is further converted into the longshore component of the surface currents. For the estimation of longshore currents, our approach is first tested using synthetic timestack examples created using anisotropic Gaussian random current fields. Comparisons between estimates derived by our algorithm and manual operator detection from videos are performed showing good agreement. These videos come from a field campaign conducted in the Mataquito River mouth area in the Maule region (Chile). Field test comparisons were also made against in situ current meter from the 2008 Truc Vert experiment in Aquitaine (France). It was taking place during an energetic event.
Aps, R., Tõnisson, H, Anfuso, G., Perales, J.A., Orviku, K., Suursaar, Ü. 2014. Incorporating dynamic factors to the Environmental Sensitivity Index (ESI) shoreline classification - Estonian and Spanish examples. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 235–240, ISSN 0749-0208.
Oil transportation is growing in the Baltic Sea area and especially in the Gulf of Finland where it will reach approximately 180–200 million tons a year by 2020. Growing oil transportation is considerably contributing to the risk of accidental spill-related shoreline oiling. This paper focuses on amending the Environmental Sensitivity Index (ESI) related shoreline classification to local conditions by dynamically changing the categorization of the shoreline in terms of its susceptibility to spilled oil caused by extreme meteorological events. This takes into consideration a number of natural physical factors. The paper presents the results of two European case studies: the Estonian shoreline of the Gulf of Finland (Baltic Sea), and the Spanish coast of the Gibraltar Strait. Susceptibility to spilled oil of some categories of the Estonian shoreline (sandy shores, till shores and gravel shores) occasionally changes over time from low to high sensitivity and back; especially conditioned to the influence of heavy storms. The studies carried out in Spain revealed a well recognizable indirect proportionality between foreshore slope and the tidal range. At many locations, the dynamic morphological characteristics of the beach appeared to be largely determined by contouring and specific conditions that are modifying the initial ESI related categorization of the sandy beaches concerned. The novelty of this work is in attempt to move from the standard ESI related, and locally adapted, static shoreline classification towards more dynamic shoreline monitoring based on characterization of the elements sensitive to oil pollution on shorelines.
Bruno, M.F., Molfetta, M.G., Petrillo, A.F., 2014. The influence of interannual variability of mean sea level in the Adriatic Sea on extreme values. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 241–246, ISSN 0749-0208.
The analysis of sea level data, in the low and middle Adriatic (south of Italy),collected by 6 stations belonging to the National Tide Gauge Network and to Apulia Region Meteomarine Network, shows a generalized increase in the mean sea level from 2008. The change between 2007 and 2009 is in the order of about 10 cm. A GPD distribution has been fitted to extreme series (5 extremes per year from 1999 to 2012) of sea level observed values, observed levels corrected with current annual mean sea level and tidal residuals. The analysis shows a significant increase in extremes of sea level values, while the extremes of corrected observed values and tidal residuals are quite similar respect to those found using observed data updated to 2006. Due to the sea level increase, the extremes, in observed sea level, rise drastically when updating time series to 2012, but, removing the effect of Mean Sea Level (MSL), these differences significantly decrease in the return levels.
Carrasco, A.R., Reis, M.T., Neves, M.G., Ferreira, Ó., Matias, A, Almeida, S., 2014. Overtopping hazard on a rubble mound breakwater. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 247–252, ISSN 0749-0208.
A major concern of coastal engineering is not only to access the damage to coastal structures by severe wave overtopping, but also the hazard imposed to users. Local hazard is often associated to the volume of overtopping water per unit of time (called overtopping discharge). Despite two decades of intensive research, it is yet not fully clear to practitioners what is the best method to compute the discharge parameter and its application on the assessment of local hazard. This work provides insight into the overtopping characterization in rubble mound breakwaters, by distinguishing different methods to assess hazardous overtopping. Fieldwork was conducted over a tidal cycle in a breakwater located at Albufeira Harbour (South coast of Portugal) under storm conditions (Hso~ 3 m; Tp ~ 9 s). Mean overtopping discharges were calculated from field measurements of flow depths and velocities at the breakwater slope armour and at the impermeable crest. Two different velocities were calculated: overtopping leading-edge velocity and overtopping peak velocity. The two methods provided similar results, with higher velocities occurring during high-tide (between 2 and 10 m/s). Mean overtopping discharges at the beginning of the impermeable crest ranged between 0.2 and 0.8 l/s/m. Under the measured hydrodynamic conditions, the breakwater offers risk to all types of pedestrians. Additionally it is shown that field measurements compare relatively well with empirical prediction methods (for the overall analysed overtopping events), namely the corrected NN_OVERTOPPING2 neural network tool. Besides contributing to the overall database on wave overtopping in coastal structures, the presented results can also be used for calibration and validation of overtopping evaluation methods (empirical formulae, artificial neural networks and numerical and physical models).
Aramuge, A., Rocha, A., Silva, P.A, 2014. A contribution to climate change assessment of storm surge along the coast of Mozambique. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 253–258, ISSN 0749-0208.
About two-third of total population of Mozambique lives along the coast which is 2700 km long. Mozambique is affected by tropical cyclones which are formed in the Indian Ocean, most of them inducing storm surges along the coast. This study presents an analytical model to estimate sea level changes, particularly extreme events (storm surges) from atmospheric pressure and wind data. The meteorological tides, for Maputo tide gauge station, were obtained by applying a low pass filter, with a cut off frequency of 33 hours. The analytical model was validated by comparing the generated meteorological residuals, trough inverted barometer and wind forcing, against the meteorological residual obtained from the tidal gauge. The analysis of the distribution curves of relative and cumulative frequencies, allowed the definition of three classes of storm surges namely: significant, very significant and highly significant for the percentile of 95, 99 and 99.9 respectively. There is a good agreement with a high correlation between the results obtained from the two methods. The alongshore wind, mainly from south or southeast, represents the main contribution for storm surge generation. The analytical model will be used to evaluate changes in the statistical properties of storm surges for future climate change scenarios along the Mozambican coast.
Guisado-Pintado, E., Malvárez, G., Navas, F., Carrero, R., 2014. Storms based morphodynamics from wave energy dissipation for beach characterisation. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 259–265, ISSN 0749-0208.
High energy events are responsible for most significant and visible changes in beach morphology and sediment disposal in a short temporal scale. Storms are associated with damage to the coastal ecosystem and societal services such as severe shoreline erosion, collapse of coastal infrastructures and properties (ports, seawalls). These also affect the effectiveness of coastal defence works such as beach nourishment. In a scenario of climate change, with predictions of sea level rise and an increase in storminess being the most important threats affecting the coastal environments, the understanding of wave climate and the role of high energy events are of key importance. In this paper an index for the characterisation of modal regimes and extreme wave events, based on a 10-year wave hindcast on a 1-hour basis, is developed to characterize wave storms regime of the Andalusia region of southern Spain. Results of the implementation of this method are presented through two case studies; one concerning a low-energy environment located on the Mediterranean coast and other for the higher energy Atlantic coast. Analysis and characterisation of the wave parameters during modal and storm conditions and the study of the spatial distribution of wave energy dissipation patterns, among other hydrodynamic parameter such as wave orbital velocity, are carried out and implemented through a morphodynamic index for nearshore environments. Results show the variability of wave energy dissipation patterns among both study sites, the role of the nearshore topography and the adaptation of the surf zone in wave hydrodynamic processes. Further, the morphodynamic resilience helps in identifying the potential for changing behaviour in energy dissipation and morphological effects derived from high energy events when compared with low-energy modal conditions.
Liu, K.., McCloskey, T.A., Bianchette, T.A., Keller, G., Lam, N.S.N., Cable, J.E., Arriola, J. 2014. Hurricane Isaac Storm Surge Deposition in a Coastal Wetland along Lake Pontchartrain, Southern Louisiana. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 266–271, ISSN 0749-0208.
Hurricanes play an important role in shaping the coast of Louisiana. Although the sedimentary signatures of hurricane deposits have been documented in several different coastal environments along the northern Gulf coast, no studies have as yet documented the signatures in wetlands adjacent to large, inland brackish water bodies. In this paper we present results of a case study documenting the distribution and characteristics of storm surge deposits related to Hurricane Isaac (2012) in a wetland on the western shore of Lake Pontchartrain, Louisiana. Hurricane Isaac, a category1 storm, made landfall near the mouth of the Mississippi River on August 28, 2012. Due to its large size and slow movement, Isaac generated strong easterly winds across Lake Pontchartrain, producing a large storm surge along the west shore of the lake and unprecedented flooding in the surrounding lowlands. Loss-on-ignition, XRF, radioisotopic, and grain-size analyses conducted on sediment cores and surface samples from the area identify two distinct sedimentary signatures for the Hurricane Isaac deposits. Near the lake shore the signature is characterized by a laminated silty sand with a geochemical profile closely resembling that of lake bed material. Storm deposits located in a brackish swamp ~ 1km inland consist of a dark, low-organic mud with low concentrations of terrestrial metals and elevated concentrations of Br, S, and Cl. Differences in the storm signal are explained by the differing effect of topographical features on the depositional and transportation processes occurring at the two sites. Utilizing the geochemical/compositional signatures as a hurricane-generated storm surge proxy indicates the possible occurrence of a similar event predating the historical record.
Lau, A.Y.A., Etienne, S., Terry, J.P., Switzer, A.D., Lee, Y.S., 2014. A preliminary study of the distribution, sizes and orientations of large reef-top coral boulders deposited by extreme waves at Makemo Atoll, French Polynesia. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 272–277, ISSN 0749-0208.
The history of extreme wave events on the Tuamotu Archipelago of French Polynesia in the central South Pacific remains poorly understood, even though huge wave deposited coastal boulders were identified in the area decades ago. Numerous large coral boulders deposited on the reef flats of Makemo Atoll (16.56°S, 143.73°W) were investigated in this study in an attempt to understand the characteristics of extreme wave events in the region. The positions, dimensions and orientations of 286 boulders were measured along over 15 km of the northern coastline of the atoll. The biggest clast measures over 130 m3 in size and it weighs more than 310 tonnes. The size-distribution of the Makemo boulders suggests that these huge clasts were transported by extreme storm waves. The long-axes of boulders are mostly aligned parallel to sub-parallel to the shoreline. However, a relationship between the boulder size and orientation was not found, suggesting the orientation of boulders is not representative of boulder transport mode.
Kim, C.S., Lim, H.S., Jeong, J.Y., Shim, J.S., Moon, I.J., Oh, Y.J., You, H.Y., 2014. Response of Coastal Waters in Yellow Sea to Typhoon Bolaven. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 278–283, ISSN 0749-0208.
In August 2012, Typhoon Bolaven (1215) passed through the East China Sea (ECS) and the Yellow Sea (YS), leading to severe coastal damages in Korea. This study investigated the responses of the coastal waters along the meridional direction of the YS and the ECS to Typhoon Bolaven. This included the causes of record-breaking high waves in the ECS, the possible danger of coincident peak surges and high tides, resonant coupling between the typhoon, tides and topography, and the impact of Bolaven-induced sea surface cooling on the intensity of Typhoon Tembin (1214). Analyses were conducted using observations from an ocean platform, buoys, and tidal stations, as well as a numerical model during the passage of Bolaven. Results revealed that the western coast of the Korean Peninsula fortunately avoided severe storm surge damages due to weak tidal action during the passage of Bolaven, although pure surge components were significantly high. However, we found that there was the possibility of resonant coupling between surges, tides and topography in the YS, which would contribute to further enhancement of the storm surge. Based on the wave simulations, it was revealed that a straight track and fast translation of Bolaven maximized the production of record-breaking high waves in the ECS.
Ha, T., Choi, J.-Y., Yoo, J., Chun, I., Shim, J., 2014. Transformation of small-scale meteorological tsunami due to terrain complexity on western coast of Korea. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 284–289, ISSN 0749-0208.
On the 4th of May, 2008, a meteorological tsunami occurred in the Yellow Sea and abnormal waves were observed at Jukdo Island, located on the western coast of Boryeong, Korea. The event attracted the attention of many engineers and scientists because it caused extreme waves only at Jukdo Island, unlike the meteorological tsunami event in 2007, which caused abnormal extreme waves along the western coast of Korea. In general, a meteorological tsunami can be forecasted using large-scale meteorological observation data and climate modeling systems. However, a small-scale meteorological tsunami like the event that occurred in 2008, which can cause abnormal extreme waves only in specific coastal areas, should be analyzed using a high-resolution modeling system because water motions can be affected by local terrain. In this study, numerical experiments were conducted to identify the generation and amplification mechanisms of the meteorological tsunami that hit Jukdo Island in 2008. To achieve this objective, we generated virtual meteorological tsunamis using atmospheric pressure disturbances observed in 2008 and simulated the propagation and run-up of the meteorological tsunamis over real topographies by varying specific characteristics of the local terrain. A three-dimensional hydrodynamic model, MOHID, and a Boussinesq-type wave model, FUNWAVE-TVD Version 2.0, were employed to simulate the generation and transformation of the meteorological tsunamis, respectively. The numerical models were first validated by comparing the numerical results with the available tidal records observed during the event, and then used to identify the generation and amplification mechanism of the meteorological tsunami that hit Jukdo Island. Finally, the transformation of a small-scale meteorological tsunami due to terrain complexity is discussed in detail.
Spencer, D., Lemckert, C.J., Yu, Y., Gustafson, J., Lee, S.Y., Zhang, H., 2014. Quantifying Dispersion in an Estuary: A Lagrangian Drifter Approach. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 029–034, ISSN 0749-0208.
Describing the physical drivers of water bodies plays an integral role in the marine environment. Lagrangian drifters are used to describe hydrodynamics, where tracking groups (clusters) of drifting floats is performed to determine the dispersion behaviour in the water. Using two types of Lagrangian drifters released in Moreton Bay, Australia, the dispersion behaviour is determined over the duration of a semi-diurnal spring tide cycle. A Self-Locating Datum Marker Buoy (SLDMB) was designed as the first drifter type. The second drifter (Small Drifter) was designed to be approximately half the size of the SLDMB. SLDMB and Small Drifter clusters were deployed for approximately 16hrs and 9–12hrs, respectively. Their trajectories and dispersion were influenced by the oscillating tidal current during the course of the drifter deployment, as well as fluctuating wind speed and direction. The Small Drifters exhibited a higher degree of dispersion than the SLDMBs; illustrating that the different drifter design had a significant impact on their susceptibility to wind induced shear dispersion – a consideration that all drogue based studies need to consider when interpreting results. A MIKE 3 model was used to assist with the investigation at hand using a dispersion coefficient of 0.2m2/s. The model required further adjustments with respect to tidal forcing and bathymetry resolution in order to enhance dispersion simulation.
Radermacher, M., Wengrove, M.E., Van Thiel de Vries, J.S.M., Holman, R.A., 2014. Applicability of video-derived bathymetry estimates to nearshore current model predictions. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 290–295, ISSN 0749-0208.
In the framework of swimmer safety, coastal managers desire accurate nearshore current predictions obtained from numerical models. To this end, detailed and up-to-date bathymetry is a necessity. Remote sensing techniques for bathymetry estimation are a promising solution. The focus of this paper is to assess the performance of wavenumber-based bathymetric inversion using Argus imagery (also known as the cBathy algorithm) as a feasible input bathymetry for numerical models to make reasonable nearshore current predictions. Numerical flow simulations on a cBathy bed are compared to simulations on an in-situ surveyed bathymetry. Results demonstrate that simulated nearshore currents on a cBathy bathymetry have a root-mean-square error in the order of 10 cm/s (magnitude) and 40 degrees (direction) when compared to simulated currents on a surveyed bathymetry. In the intertidal zone cBathy should be combined with a different method for bathymetry estimation in order to decrease these errors.
Oh, S.-H., Jeong, W.-M., 2014. Extensive monitoring and intensive analysis of extreme winter-season wave events on the Korean east coast. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 296–301, ISSN 0749-0208.
Extensive wave monitoring was carried out over nine consecutive years at nine different locations along the east coast of Korea in order to examine the overall wave statistics and to investigate the generation and propagation mechanism of occasional high waves in this region. This type of long-term wave observation at multiple stations has never been performed on the Korean east coast. Appearances of high waves, defined by criteria of Hs≥3 m and Ts≥9 s at any of the nine stations within a single day accounted for approximately 5% of the total data. These high waves mostly occurred in winter under the influence of strongly developed winter storms over the East Sea. Among these high wave events, three representative cases were subjected to a further intensive analysis by using the corresponding wave data together with meteorological data at that time. Based on such a synthetic analysis, it was possible to understand details regarding the general patterns in the development of low pressures and subsequent formation of strong wind fields around the coastal zone, which eventually affected the characteristics of the high waves that were observed.
Iida, T., Kure, S., Udo, K., Mano, A., Tanaka, H., 2014. Breach process simulation of coastal levees broken by 2011 tsunami. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 302–307, ISSN 0749-0208.
On March 11, 2011, a tsunami hit the Sendai Bay Coast and broke 80% of the coastal levees. The areas around the breached levees were scoured deeply, causing serious adverse effects on post-disaster reconstruction efforts. This motivated us to analyze the mechanism of the local scour in the areas around breached levees. We collected and investigated various data such as aerial photographs and tsunami videos. As the results of the investigation, we found the breach points progressing in two steps. Firstly, the brittle structure was destroyed by the first leading wave. Secondly, the concentration of the return flow eroded and breached levees with the broken points from the first step. In order to understand the details of the second step, a numerical simulation was conducted using a finite volume method. From the result of the simulation, the scouring mechanism around breached levees was analyzed and discussed.
Naquin, J.D., Liu, K.B., McCloskey, T.A., Bianchette, T.A., 2014. Storm Deposition Induced by Hurricanes in a Subsiding Coastal Zone. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium(Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 308–313, ISSN 0749-0208.
To understand the geological processes induced by tropical cyclones, geochemical and sedimentological analyses were performed on a 3 m sediment core (basal 14C date of 940 /− 50 years BP) extracted from a marsh adjacent to a backbarrier lake along Louisiana's Gulf of Mexico coast (USA). This study was conducted in order to identify the geologic changes within a subsiding coastal region in the light of coastal recession and past hurricane activity. Previous studies show that Bay Champagne, a semi-circular lake near Port Fourchon, Louisiana, is subjected to subsidence rates between 1.0 and 1.2 cm year−1, the highest rate of retreat within the entire northern Gulf of Mexico. Loss-on-ignition (LOI) and X-ray fluorescence (XRF) analyses, employed to generate lithological and geochemical core profiles, identified three distinct sand layers measuring up to 50 cm in thickness deposited by recent hurricanes. LOI shows large decreases in water, organic, and carbonate contents, indicating the occurrence of marine inundation. Within each marine incursion layer terrestrial elemental concentrations as determined by XRF display large depletions. Grain size analysis of a portion of the core (30–86 cm) indicates the presence of two series of sequential high-energy storm deposits followed by intense fluvial flooding within Bay Champagne. These events are attributed to Hurricanes Katrina/Rita in 2005 and Gustav/Ike in 2008
Rangel- Buitrago, N., Anfuso, G., Alvarez, O., Phillips, M., Thomas, T., M. Forero. 2013. Characterization of wave climate and extreme events into the SW Spanish and Wales coasts as a first step to define their wave energy potential. Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 314–319, ISSN 0749-0208.
The characterization of wave climate and extreme events is a key issue for planning coastal and offshore activities. The energy sector is obliged to use alternative sources directed towards environment friendly renewable energy. Ocean waves constitute a potential source of this kind of energy and detailed knowledge of site specific wave climates constitutes the first step in developing a wave energy system. Consequently, this work deals with the analysis of wave climate at Cadiz (SW Spanish Atlantic coast) and Tenby (S Wales, UK). At the former site, wave records include 22 years of data covering the period between 1987 and 2008. Offshore wave climate showed clear cyclic variations in average monthly significant wave height (Hs). Waves were usually low (Hs<0.8 m, Cadiz - Hs<1.0 m, Tenby) from May to August (late spring to summer), reaching minimum values in August (Hs = 0.6 m Cadiz - Hs = 1.0 m Tenby). Winter waves rapidly increased in height, reaching peak values (Hs = 1.2 m, Cadiz, Hs = 2.1 m, Tenby) between December and January. Energy patterns calculated using the equation of wave energy flux, showed monthly averages at Cadiz and Tenby of circa 5 kW/m and 15 kW/m respectively that reached average values of 37 kW/m and 155 kW/m respectively, during winter. Despite this, Atlantic coastal locations receive less attention when compared with other coastlines around the world since they are considered to be relatively calm areas. Wave power values recorded in this research suggest that the SW Spanish Atlantic and South Wales coastal areas are potential sources of renewable energy.
Dias, J.M., Lopes, C.L., Coelho, C., Pereira, C., Alves, F.L., Sousa, L.P., Antunes, I.C., Fernandes, M. da L., Phillips, M.R., 2014. Influence of mean sea level rise on Ria de Aveiro littoral: adaptation strategies for flooding events and shoreline retreat. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 320–325, ISSN 0749-0208.
Floods and shoreline retreat in coastal areas threaten many millions of people across Europe. Moreover, it is agreed that climate change can amplify the magnitude and frequency of flooding events and accelerate the shoreline retreat. The main goal of this work is to assess flood and shoreline retreat risk, and define adaptation strategies under present conditions and future climate change scenarios on the Ria de Aveiro and its littoral. The hydrodynamic model ELCIRC was implemented for the Ria de Aveiro lagoon and GENESIS (U.S. Army Corps of Engineers) and LTC (Long-Term Configuration) shoreline evolution models for the littoral stretch between Esmoriz and Mira. Numerical results in present and future scenarios were used to map the flooded lagoon extension and the shoreline evolution of this coastal stretch. Analysis showed an increase of the lagoon's flooded area, relative to the present, with regions more exposed to sea level rise being lowland areas located at the margins of the lagoon's deeper channels. Examination of the littoral stretch showed a slight increasing trend of shoreline retreat under predicted future climate change scenarios, thereby increasing the probability of sand spit rupture. Data from numerical predictions were integrated into Geographical Information Systems covering the coastal and lagoon study areas, and produced hazard and risk maps including the identification of regional use and activities. Structural and non-structural measures were subsequently developed in order to mitigate flood and shoreline retreat effects.
Loureiro, C., Ferreira, Ó., Cooper, J.A.G., 2014. Non-uniformity of storm impacts on three high-energy embayed beaches. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 326–331, ISSN 0749-0208.
Coastal storms are highly significant and destructive events and important natural hazards that have major impacts upon the physical and human-cultural coastline environments. Exceptional coastal storms in the last decades have emphasized the urgent need to reinforce scientific knowledge regarding the frequency, impact and role of these extreme events. This is particularly relevant for embayed beaches, where geomorphological control promotes characteristic morphodynamic responses that are distinct from the better studied long-linear beaches. This paper analyses storm response from datasets of morphological change obtained from three embayments located in three distinct wave environments. Analysis of the morphological response to extreme storm events, particularly the 2007 March Equinox storm in eastern South Africa, the January-February 2009 storm group in southwestern Portugal and the December 2011–January 2012 storm group in northwestern Ireland, demonstrate that storm-induced morphological change in the Durban Bight, Arrifana beach and Portstewart Strand is highly variable alongshore. Retreat values for the mean high water spring shoreline are shown to differ significantly within each embayment. This alongshore non-uniform response to storm-events is attributed to boundary effects triggered by the presence of natural headlands or outcrops and/or artificial engineering structures. Megarip development drives variability in storm response in Arrifana, while wave shadowing and interruption of longshore sediment movement under south-easterly/west-northwesterly storm waves promotes the northward/westward increase in shoreline retreat in the Durban Bight and Portstewart Strand, respectively. Boundary effects significantly influence short-term morphodynamic behaviour during storms and, consequently, determine alongshore non-uniform morphologic response to storm events, irrespective of embayment dimensions and event magnitude.
Yoon, S.B., Kim, S.C., Baek, U., Bae, J.S., 2014. Effect of Bathymetry on Propagation of Tsunamis towards the East Coast of Korea. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 332–337, ISSN 0749-0208.
In this study the effect of underwater topography of the East Sea on the propagation of tsunamis towards the Korean Peninsula is investigated using the dispersion-correction finite difference numerical model. A series of numerical simulations are conducted for three tsunami events including the 1964 Niigata Tsunami, the 1983 Central East Sea Tsunami and the 1993 Hokkaido South-West Sea Tsunami for the cases of examining the individual or combined influence of underwater topographic features. These include the Yamato Rise, a submerged ridge connecting Yamato Rise and the Shimane Peninsula of Japan, and K-shaped submerged ridges emerging from the east coast of Korea towards the East Sea. In particular, in order to evaluate quantitatively the effects of underwater topography on the propagation of tsunamis, a new concept of energy discharge per unit width is introduced. Using this concept, the quantitative analyses of energy propagation during tsunami events are performed. The analyses show that the underwater topographies including the submerged rises and ridges capture the tsunami energy and transport it to coastal areas connected to those topographies.
Kazimierz Furmańczyk, Paweł Andrzejewski, Rafał Benedyczak, Natalia Bugajny, Łukasz Cieszyński, Joanna Dudzińska-Nowak, Andrzej Giza, Dominik Paprotny, Paweł Terefenko, Tomasz Zawiślak
Furmańczyk, K., Andrzejewski, P., Benedyczak, R., Bugajny, N., Cieszyński, Ł., Dudzińska-Nowak, J., Giza, A., Paprotny, D., Terefenko, P., Zawiślak, T., 2014. Recording of selected effects and hazards caused by current and expected storm events in the Baltic Sea coastal zone. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 338–342, ISSN 0749-0208.
Routine monitoring has already become a legal obligation and apparent necessity for EU members, especially of such dynamic and important habitat as the Baltic Sea and its shores. One of the subsystems of SatBałtyk, a Polish research project for maritime observation, is dedicated to coastal monitoring. It focuses on recording and forecasting the consequences of storm events along the Baltic's Polish shoreline. Three sites (7–12 km-long sections of dune coast) were selected for detailed research: the Dziwnow Spit, Jamno and Bukowo lakes' spits and part of the Hel Peninsula. Work started in 2010 and will continue until 2015. A numerical model, XBeach, was implemented in order to provide forecasts of several parameters, i.e. beach flooding, dune erosion, suspension of matter in the water after storm and rip current occurrence. It combines external data with in situ measurements by the researchers. Many pieces of equipment were installed for this research: a satellite receiving station, underwater probe ADCP (Acoustic Doppler Current Profiler), a tide gauge, a hyperspectral radiometer and two video cameras for constant shoreline observation. The system is currently being calibrated and verified; an online visualisation available to the public is due to be launched as a long-lasting outcome of the project.
Mawdsley, R.J., Haigh, I.D., Wells, N.C., 2014. Global changes in tidal high water, low water and range. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 343–348, ISSN 0749-0208.
Impacts of extreme sea levels are increasing as the population and infrastructure in coastal zones increases. Extreme high sea levels generally increased at a similar rate to mean sea level through the twentieth century at most sites around the world, suggesting that the same mechanisms are driving both increases. However, the simplicity of this conclusion belies the fact that many mechanisms known to act on the different components of sea level, have been observed to change in local and regional studies. Using a ‘quasi-global’ dataset of sea level records, this paper investigates changes in the tidal component of sea level and shows that changes in mean high and low waters, and hence tidal range, are occurring over long-time scales at many sites around the world. Over half of the selected sites show significant trends in tidal range datums, but no clear spatial patterns of change exist, suggesting that mechanisms are affecting the tide on local scales. Trends are dependent on the tidal datum selected which has wide-ranging practical applications given the variety of uses of tidal datums.
Smith, A.M, Green, A.N, Cooper, J.A.G. et al., 2014. Cliff-top storm deposits (55-63m amsl) from Morgan Bay, South Africa. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 349–353, ISSN 0749-0208.
Cliff-top storm deposits (CTSDs) occur south of Morgan Bay, South Africa at elevations varying from ±55- to 63m. These occur as a ±10m-wide horizontal fringe of shell breccia mixed into a very thin (>15cm) sandy soil on the cliff top platform. Visually it is evident that the shell breccia is of various ages. Comparisons with proven wave breccia from this area indicate the same source. We suggest that this breccia was deposited as fall-out from wave and wind-borne plumes produced by wave bores striking the cliff base. These bores would likely have been produced by waves at least ~40m in height. Alternative interpretations, such as a perched marine desposit or tsunamiite are rejected in favour of CTSDs produced by multiple large wave events.
Jinsung Seo, Bumshick Shin, Kyuhan Kim, 2014. Monitoring System of High Waves and Tsunami using HF Ocean Radar in the East Coast of Korea, Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 035–040, ISSN 0749-0208.
The east coast of Korea is exposed to the danger of tsunamis because it is contiguous to Japan. Damages took place in the region when tsunami occurred in the west of Japan in 1986 and 1993. Fear of the destruction caused by has increased following the 2011 Great Tsunami of Japan. The west coast of Japan embodies many high tsunami risk areas where tsunami may be triggered by earthquakes. As no earthquake has ever occurred there, these high risk areas contain high amount of potential energy. Furthermore, frequent high waves due to climate change have become one of the major factors with respect to coastal structure damage, beach erosion and various coastal disasters along the shoreline. In order to make a counterplan for coastal disaster, precise analysis of the high wave characteristics, through continuous monitoring, is essential. In this study, continuous long-term observation is implemented with an Ocean Radar. Ocean Radar conducts remote observation equipped with ground-based radars which enable series of simultaneous observations of extensive range of the coast with high frequency. Ocean Radar for continuous long-term observation is operated at Samcheok on the east coast of Korea. Samcheok has experienced tsunami damage in previous years and is where a nuclear power plant is located. In order to examine the reliability of the Ocean Radar, a pressure-type wave gauge, ultrasonic wave gauge, and ocean buoy are installed for data comparison and verification. The Ocean Radar used in this study is an array-type HF-RADAR named WERA (WavE RAdar). Data analysis of the continuous long-term observation verifies more than 90% of the wave data collected within 25km range from the center of two sites. Only less than 1% of the entire observation is unmeasured by time series analysis, but data from other wave gauges show similar features. Moreover, a comprehensive monitoring system supported by such observations is developed for the public for internet based real-time reports on waves and currents.
Sembiring, L., Van Dongeren, A., Winter, G., Van Ormondt, M., Briere, C., Roelvink, D., 2014. Nearshore bathymetry from video and the application on rip current predictions for The Dutch Coast. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 354–359, ISSN 0749-0208.
This paper demonstrates the potential use of nearshore bathymetry estimated from video data in a coastal operational model for the Dutch Coast, which provides daily forecast of waves, water levels and (rip) currents. Two video techniques to obtain beach bathymetry from video data- Beach Wizard and CBathy are validated against jet ski surveyed bathymetry. Both methods show good agreement with surveyed data, and bathymetric features of the beach are adequately produced. To assess the applicability of video-derived bathymetry for the purpose of rip current predictions, a model is built for Egmond aan Zee in The Netherlands, in which rip current predictions based on video-derived bathymetry are compared with those based on the jetski survey. Results show that predicted maximum mean offshore-directed (rip) velocities are in good agreement when using surveyed bathymetry (reference model) and video-derived bathymetry. Finally, to address the rip current forecasting skill, this local model is forced by wave boundary conditions obtained from a larger-scale wave prediction model, in addition to the bathymetry from video. Results show that useful information can still be obtained regarding the rip currents' flow where maximum offshore-directed velocities obtained from the predictive model resemble adequately rip currents pattern in the reference model. This paper will discuss each component of the model system and the validation result on hindcasting and forecasting rip currents.
Suh, S.W., 2014. Massive Cooling Water Dispersion in a Shallow Macro-tidal Coastal Zone in Korea. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 360–365, ISSN 0749-0208.
The Hanbit Nuclear Power Plant is located on a macro-tidal coastline in mid-western Korea; it generates 5900 MW of electricity through 6 units. It discharges 354.6 m3 s−1 of cooling water, with excess temperature of ΔT = 7.6 °C, into the shallow coastal water. The mean depth around the Hanbit NPP is ~10 m, in which strong tidal currents of >1.0 m s−1 occur during spring tides. This study examines the complex thermal dispersion in a shallow sea environment. To accurately delineate the dispersion characteristics, 15 sets of seasonal field observations for wave, tide, tidal currents, and water temperature were conducted over 3 years from 2002 to 2004. Water temperature at 30 stations around the power plant was measured simultaneously over a 15-day period to investigate seasonal changes in the tidal hydrodynamics. Spectral analysis was employed to understand the dominant semidiurnal forcing upon thermal plume movement. The results revealed that wide thermal plumes were spreading beyond the regional tidal excursion. Numerical models based on two-dimensional hydrodynamic advanced circulation (ADCIRC) and fine-grid Eulerian-Lagrangian transport models were also developed, which reproduced the results of the field observations with satisfaction.
Van Dongeren, A., Ciavola, P., Viavattene, C., De Kleermaeker, S., Martinez, G., Ferreira, O., Costa C., R. McCall, 2014. RISC-KIT: Resilience-Increasing Strategies for Coasts–toolkit. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 366–371, ISSN 0749-0208.
Recent and historic high-impact events have demonstrated the flood risks faced by exposed coastal areas. These risks will increase due to climate change and economic development. This requires a re-evaluation of coastal disaster risk reduction DRR strategies and prevention, mitigation and preparedness PMP measures. To this end, the UN Office for Disaster Risk Reduction formulated the Hyogo Framework for Action, and the EU has issued the Floods Directive. By their nature, neither is specific about the methods to be used to assess coastal risks, particularly those risks resulting from dune and structure overtopping, the non-stationarity of surge and flash flood events, and coastal morphodynamic response. This paper describes a set of open-source and open-access methods, tools and management approaches to fill this gap. A Coastal Risk Assessment Framework will assess coastal risk at a regional scale. Thus critical hotspots can be identified for which an impact-oriented Early Warning System/Decision Support System is developed. This can be applied in dual mode: as a forecast and warning system and as an ex-ante planning tool to evaluate the vulnerability. The tools are demonstrated on case study sites on a range of EU coasts with diverse geomorphic settings, land use, forcing, hazard types and socio-economic, cultural and environmental characteristics. Specific DRR plans will be developed for all sites. A management guide of PMP measures and management approaches is to be developed. The toolkit will benefit forecasting and civil protection agencies, coastal managers, local government, community members, NGOs, the general public and scientists.
Aps, R., Tõnisson, H, Anfuso, G., Perales, J.A., Orviku, K., Suursaar, Ü. 2014. Incorporating dynamics factor to the Environmental Sensitivity Index (ESI) shoreline classification Estonian and Spanish example. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 372–377, ISSN 0749-0208.
Oil transportation is growing in the Baltic Sea area and especially in the Gulf of Finland where it is reaching approximately 180–200 million tons a year by 2020. Growing oil transportation is considerably contributing to the risk of accidental spill related shoreline oiling. This paper focuses on amending the Environmental Sensitivity Index (ESI) related shoreline classification to local conditions by dynamically changing the categorization of shoreline in terms of its susceptibility to spilled oil caused by extreme meteorological events and taking into consideration a number of natural physical factors. The paper presents the results of two European case studies: the Estonian shoreline of the Gulf of Finland (Baltic Sea), and the Spanish coast of the Gibraltar Strait. Susceptibility to spilled oil of some categories of the Estonian shoreline (sandy shores, till shores and gravel shores) is occasionally changing over time from low to high sensitivity and back, and that especially conditioned to the influence of heavy storms. The studies carried out in Spain revealed a well recognizable indirect proportionality between foreshore slope and the tidal range. At many locations, the dynamic morphological characteristics of the beach appeared to be largely determined by contouring and specific conditions that are modifying the initial ESI related categorization of the sandy beaches concerned. The novelty of this work is in attempt to move from the standard ESI related and locally adapted static shoreline classification towards more dynamic shoreline monitoring based on characterization of the sensitive to oil pollution shoreline elements.
Karymbalis, E., Chalkias, C., Ferentinou, M., Chalkias, G., Magklara, M. 2014. Assessment of the Sensitivity of Salamina (Saronic Gulf) and Elafonissos (Lakonic Gulf) islands to Sea-level Rise. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 378–384, ISSN 0749-0208.
This paper deals with the classification of the coasts of two Greek islands (Salamina and Elafonissos), according to the sensitivity to long-term sea-level rise by applying the Coastal Sensitivity Index (CSI). Salamina lies in the Saronic Gulf about 2 km off-coast from Piraeus (the port of Athens). The island has an area of 93.5 km2 while the total length of the coastline is 131.3 km. Elafonissos has an area of 19 km2 (coastline length: 30.4 km) and lies west of cape Maleas in the Lakonic Gulf (South-east Peloponnese). CSI calculation involves the physical variables of geomorphology, coastal slope, relative sea-level rise rate, shoreline change rate, mean tidal range and mean wave height, in a quantifiable manner. Every section of the coastline is assigned a risk ranking based on each variable, and the CSI is calculated as the square root of the product of the ranked variables divided by the total number of variables. CSI maps which were produced for the studied islands showed that Elafonissos is more susceptible to a future sea-level rise since an extensive length of its coast (16.7 km, corresponding to 54.5% of the entire coastline) is characterized as highly and very highly sensitive primarily due to the low topography and the presence of extensive sandy beaches. On the other hand only 2 km of Salaminas' shoreline, corresponding to 1.5% of the entire coast of the island, is of high sensitivity. Areas of high and very high CSI values host socio-economically important land uses (urban areas and recreational activities).
Borges, P., Phillips, M.R., Ng, K., Medeiros, A., Calado, H., 2014. Preliminary coastal vulnerability assessment for Pico Island (Azores). In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 385–388, ISSN 0749-0208.
The SMARTPARKS project (PTDC/AAC-AMB/098786/2008), funded by the Portuguese Foundation for Science and Technology (FCT), aims at establishing a planning and management system for small island (SI) protected areas (PA). Diverging from traditional no-take zone protected areas this project strives to integrate human activities, economic and cultural development, and conservation objectives. Pico Island in the Azores archipelago was selected as a suitable case study site. Pico is a Natural Park with 35% of its area being classified as PAs. This paper presents the assessment of relative coastal vulnerability of Pico to erosion and coastal flooding in order to determine how best to manage the PAs with respects to coastal hazards. A Coastal Vulnerability Index (CVI) was developed based on remote sensing and fieldwork data whereby a set of physical coastal parameters, which serve as indicators of vulnerability, were obtained: type of cliff; exposure to swell/storm waves; outcrop flooded; and coastal defences. The CVI values were used to rate coastal segments into five classes ranging from extremely low to very high based on its relative degree of vulnerability. CVI will provide input into a decision support tool to facilitate effective planning and management on Pico Island Natural Park with the potential of adapting and extending this approach to the other SIs.
Stokes, C., Beaumont, E., Russell, P., Greaves, D., 2014. Coastal Impacts of Marine Renewables: Perception of Breaker Characteristics by Beach Water Users. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 389–394, ISSN 0749-0208.
Beach water users such as bathers and surfers are of economic importance to tourism in Cornwall, UK. Wave energy converters soon to be trialed at the ‘Wave Hub’ marine renewables test site in Cornwall, may reduce inshore wave heights and have an unknown effect on wave period, therefore potentially affecting water recreation and tourism on the beaches in its lee. There is little existing research to indicate what surf conditions are ‘preferred’ by various beach water user groups, and how they perceive different wave conditions has never been investigated. Without an understanding of how waves are observed and described by water users, little can be said about how likely they are to be affected by, or if they will correctly perceive, any changes to inshore waves caused by Wave Hub or future renewables projects. To investigate how waves are perceived, nearshore wave buoy measurements collected in 10 m water depth and transformed to breaking height, were compared to concurrent visual observations of mean breaker height and period made by 354 participants. Ratios of observed over measured height and period were used to quantify the perceptions. The vast majority of water users underestimated significant wave height and period at breaking, and their average perceptions can be approximated by Hvis ≈ 0.70Hb and Tvis ≈ 0.83T1/3 (for waves 0.5≤Hb≤ 3.5 m and 3 ≤T1/3 ≤ 15 s). Although perceptions were highly varied, average perceptions did not change significantly under different wave conditions. Perception of wave period did not change significantly between the different water user groups considered. Expert water users and surfers generally under predicted wave height the most, especially for small and/or short period waves, while novices and non-surfing water users made height observations closer to measurements.
Giovanni De Falco, Francesca Budillon, Alessandro Conforti, Sandro De Muro, Gabriella Di Martino, Sara Innangi, Angelo Perilli, Renato Tonielli, Simone Simeone
De Falco, G., Budillon, F., Conforti A., De Muro, S., Di Martino G., Innangi, S., Perilli, A., Tonielli, R., Simeone, S. 2014. Sandy beaches characterization and management of coastal erosion on western Sardinia island (Mediterranean sea).In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa),Journal of Coastal Research, Special Issue No. 70, pp. 395–400, ISSN 0749-0208.
Coastal erosion is a global problem which affects sandy and rocky shores worldwide. Coastal erosion can be triggered by several causes. Local processes can generate erosion hot spots, whereas at the global scale, the main forces are sea level rise, changes in storm climate and human interference. Beaches along the Mediterranean sea are strongly affected by coastal erosion. Recently, the Protocol on Integrated Coastal Zone Management in the Mediterranean (PAP/RAC 2007) recommended the prevention of erosion processes by restoring the natural adaptive capacity of the coast and by improving the knowledge on the state, development and impact of coastal erosion. In order to achieve the objective of the PAP/RAC protocol, we characterized 24 sandy beaches along ~270 km of the western coastline of the Sardinia island (western Mediterranean). Grain size and mineralogy of the foreshore sediments were analyzed and the intertidal elevation/bathymetric profile were measured using the Differential Global Positioning System. Aerial photos were used to identify the shoreline configuration, the number of bars and morphodynamic features. A digital elevation model (DEM) of the adjacent shelf was produced and acoustic backscatter, grab and box-corer sediment samples were collected in order to characterize the seafloor and to identify the substrate lithology, particularly the distribution of sandy sediments. The investigated coastline is characterized by linear, multibarred beaches and wide transgressive dune fields formed by terrigenous and coarse sand. These linear beaches are alternated with embayed beaches which locally show a mixed terrigenous/bioclastic carbonate composition. Large sandy bodies were found in the inner shelf, often forming dune fields which were uncovered by mud drapes. A database was created to facilitate the characterization of the beach systems along the studied coastline and adjacent inner shelf. It is anticipated that the database will be used by policy makers in support of the implementation of coastal erosion management strategies.
Gomes, R.K.S., Sousa, F.B.B., Amanajás, V.V., Santos, G.C., Pereira, L.C.C, 2014. Guidelines for the management of the coastal zone of the Amazon estuary in the Brazilian state of Amapá. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 401–406, ISSN 0749-0208.
The study area is located in the district of Anauerapucu, at the watershed of the hydrographic basins of the Matapi and Vila Nova rivers. The objective of this study was to contribute to the social diagnosis of this estuarine community. Guidelines for the effective management of this coastal area were proposed. Data were collected using structured and semi-structured questionnaires in interviews with 63.3% of the local families, and all the association leaders, as well as a survey of the available services and infrastructure, and direct observations. Following this phase, a participative approach was employed in the local community. A socio-economic profile dominated by relatively young individuals (51.1% of population under 20 years of age), with agriculture and the extraction of natural resources as the primary occupations. However, the primary source of monetary income (73%) is government benefits. The community was also characterized by low levels of schooling. The principal health problems are diarrhea and hepatitis, reflecting the poor quality of the local drinking water. Due to the lack of a public sanitation system, most households (62.3%) have cesspits, which drain into the estuary. The community has five associations, although they do not participate in the social movements that campaign for the improvement of the quality of life of the population. The principal environmental problems of the community are the poor quality of the water supply and the inadequate disposal of domestic refuse. Overall, the results of this study indicate clearly that the socio-environmental problems of the local community are derived from the lack of effective public policies or management of the estuarine coastal zone of the state of Amapá. We provided some suggestions for the improvement of the current situation found within the study area.
Esteves, L.S., Thomas, K., 2014. Managed realignment in practice in the UK: results from two independent surveys. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 407–413, ISSN 0749-0208.
Shoreline Management Plans in England envisage implementation of managed realignment along 550 km or 10% of the coastline length by 2030. About 66 km of the coastline has been realigned between 1991 and the end of 2013. Therefore, an eight-fold increase in the length of realigned shorelines is expected in the next 20 years. It is now timely to gather and evaluate experiences and lessons learned from existing experience to inform future projects. This article presents results from two surveys concerning experiences and perceptions of managed realignment in the UK. The UK is often recognised as leading the implementation of managed realignment worldwide and it is anticipated that the national experience attracts great interest of international researchers and practitioners. Findings from a qualitative survey focusing on practitioners experience are contrasted by the results from a quantitative survey allowing comparison of practitioners', consultants', researchers' and stakeholders' views. Three key issues identified through the analysis of the responses are discussed in this article: (1) the multiple functions of realignment sites should be emphasised to increase buy-in from stakeholders; (2) working in partnership with relevant organisations and landowners from the inception of project planning is highly beneficial; and (3) knowledge has greatly advanced in many aspects, but improved understanding about the long-term evolution of sites is needed. Stakeholders' views are considerably more negative about the outcomes of managed realignment, especially concerning flood risk management, when compared with other groups assessed here. Consultants' and practitioners' views are more positive, although many indicate results vary depending on the site and aspects being assessed. More than 60% of all groups agree that better understanding about long-term evolution of realigned sites is needed, especially sedimentation and biogeochemical processes. This study identifies aspects about which stakeholders' views most differ from the practical knowledge gathered from consultants, practitioners and researchers. It is suggested here that improved practice and stakeholders engagement can be achieved by obtaining and disseminating quantifiable and reliable evidence of the multiple benefits offered by realigned sites. Although these findings reflect the UK experience, they are likely to be useful to inform future initiatives elsewhere.
Araújo, M.A.V.C., Di Bona, S., Trigo-Teixeira, A., 2014. Impact of detached breakwaters on shoreline evolution: a case study on the Portuguese west coast. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 041–046, ISSN 0749-0208.
The Portuguese West Coast is facing severe erosion problems that threaten both the population andthe immediate seaside properties. Some locations, such as the Vagueira region, are especially vulnerable. In an attempt to reverse the present erosional trend, a coastal defense scheme involving two detached breakwaters was introduced in a phased manner. In this work, the impact of those two detached breakwaters on the down-drift coast is investigated. The study area extends from south of the Costa Nova village southwards to Mira. The shoreline evolution is predicted, for various decades, using the GENESIS model. The present time shoreline position, from which future situations are predicted, was obtained using LIDAR data acquired in 2011. Two different future scenarios are investigated: the ‘do-nothing’ scenario, which assumes that no further engineering interventions will be performed on the coast; and the ‘detached breakwaters protected’ scenario, with the first breakwater introduced in 2011 and the second in 2026. Depending on sediment supply, two types of simulations are carried out: calibrated simulations, which assume that the amount of sediments in the future will be equal to those in the present situation; and extreme simulations, which assume an acute shortage in sediment supply. Results show that if no further interventions are executed at the Vagueira region, the entire coastal stretch will continue to erode, which could lead to extreme consequences in some locations, depending on sediment supply. If two detached breakwaters are introduced at different intervals, a new accreting trend is predicted at the Vagueira region, reversing the present erosional phase. However, the erosional trend will continue southwards, unless a 3rd detached breakwater is introduced in Mira.
Carrero, R., Navas, F., Malvárez, G., Guisado-Pintado, E. 2014. Artificial intelligence-based models to simulate land-use changes around an estuary. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 414–419, ISSN 0749-0208.
Understanding human-driven land-use changes is a key element for successful coastal management and planning. Land-use change modelling helps to increase our comprehension of the patterns of these changes and the interacting factors affecting them. In previous years, a wide variety of land-use modelling approaches have arisen, however not all of them fit with the complex and especially dynamic behaviour of land use changes in coastal areas. In this sense, the so called ‘fifth generation’ of models represent an opportunity, as they integrate computer modelling with artificial intelligence technology allowing a more flexible and non-linear approaches that better emulate the real and complex behaviour of land use changes in rapidly evolving environments such as coastal areas. In this paper the applicability of artificial intelligence based models to simulate land-use changes is explored and applied to a specific case in a coastal stretch. First the potential of a Cellular Automata (CA) is compared with other modelling approaches. In the study CA proved to be a powerful approach due to its capacity of performing dynamic and complex spatial modelling, its affinity to work with geographic and remote sensing data, and its compatibility with other models. Second, a specific CA-Stochastic model is tested in an estuary located in southwestern Spain. The model is applied to simulate land-use changes from 1999–2007, using a spatial resolution of 10×10 m-cell, considering eight representative land-use classes, 30 different land-use transitions and fifteen variables affecting each transition. Validation based on a fuzzy similarity method is performed to compare the real and simulated maps. Results show high analytic capacity and good performance of the model. Four major strengths are identified: i) the integration of physical variables with human-controlled variables; ii) the successful simulation of multiple, simultaneous land-use changes; iii) the management of high-resolution spatial data; and iv) the flexibility of the model. In terms of its application to coastal management and planning, CA-based models not only help to understand past land use changes and the natural and human factors behind them, but also represent a great potential to forecast land use changes and create future spatial-explicit scenarios to assist decision-making in the mid-long term.
Reimann, M., Ehrlich, Ü., Tõnisson, H., 2014. Regional differences in recreational preferences of Estonian coastal landscapes. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 420–425, ISSN 0749-0208.
Estonia has rich and valuable coastal landscapes. Estonian natural coastline is classified into five shore types: cliffs, till, gravel, sandy and silty. Those shore types are well distinguishable and recognised by scientists and the general public. Shoreline types are not distributed equally, some shore types occur in all counties, other shore types are found only in certain parts of Estonia. The main aim of the current study is to assess whether people's preferences for shore types are related to the types occurring in their home county. A survey (N=1,519) was carried out on an Estonian working age population in all 15 counties, of which 7 counties have a coastline. The questionnaire contained information on Estonian shores, which were presented in coloured photos. Respondents were asked to rank the photos according to the question: “Which shore type do you prefer to visit in your leisure time?” Differences were found among preferences in various regions; however, sandy shores were highly preferred among all respondents. In other types, differences appeared. Respondents are less likely to prefer shore types which are dominant in their region than shore types which are absent or less common in their county.
Williams, A. T., Barugh, A., 2014. Beach user perceptions at the eastern Yucatan peninsula, Mexico. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 426–430, ISSN 0749-0208.
Socio-demographic parameters and beach user preferences and priorities were analysed from 160 questionnaire interviews at Playa Linda and Playa Choc-Mool in Cancun - a mega resort; Playa del Carmen (lower level resort) and Tulum, which was located in a protected area, all located along the Yucatan peninsula, Mexico. Prioritisation of 50 beach qualities were undertaken and a strong relationship (p<0.05) was found at all four beaches between perceived water quality and the presence of visual litter pollution. Litter free white sand and water quality was the highest preference and scenery was considered more important than safety at Tulum. Fifty per cent of users expressed a preference for visiting an undeveloped beach with just a few facilities (bar/toilet), with only 9.6% expressing a preference for a highly developed resort. A significant difference (p<0.05) occurred between females and males, the former preferring a beach with few facilities, the latter an undeveloped one. Similar differences were found for the presence of harmful sea creatures, the importance of toilets, presence of oil on the beach, cooking smells; sun bed hire had a much higher significant difference (p=0.02). American visitors preferred a large range of restaurants, car parks, tarmac roads; Europeans seemingly the opposite. Beach users who had travelled the furthest seemed to prefer a more natural beach, but facilities and access at commercial resorts were appreciated. Fifty percent wanted a dog ban on all beaches.
Pilkey, O.H. and Cooper, J.A.G. 2014. Are natural beaches facing extinction? In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa) Journal of Coastal Research, Special Issue, No. 70 pp. 431–436. ISSN 0749-0208.
On a generational scale, on developed shorelines, the world's recreational beaches are doomed. This is largely because of the widespread assumption that preservation of buildings is a higher priority than preservation of beaches in response to sea level rise. Continuing beach degradation will be inevitable through active or passive processes. Active degradation means the actual removal of the beach, mostly as a result of shoreline engineering or mining. By far, the most important cause of beach loss in this category will be hard structures, especially seawalls. The incorrectly but widely perceived panacea of each replenishment will become economically impossible because of raised sea levels. Replenishment leads to intensified beachfront development and this ironically and inevitably will increase the future construction of seawalls. Passive degradation refers to reduction of the quality of the beach to the point that human usage drops, along with political support for costly beach preservation by nourishment. Passive degradation includes trash accumulation, oil spills, beach driving and most importantly, pollution, which is increasing rapidly apace with population growth and remains largely unrecognized by the beach-using public.
Fátima L. Alves, Lisa P. Sousa, Tanya C. Esteves, Eduardo R. Oliveira, Inês C. Antunes, Maria da Luz Fernandes, Luís Carvalho, Sérgio Barroso, Margarida Pereira
Alves, F.L., Sousa, L.P., Esteves, T.C., Oliveira, E.R., Antunes, I.C., Fernandes, M.L., Carvalho, L., Barroso, S., Pereira, M., 2014. Trend Change(s) in Coastal Management Plans: the integration of short and medium term perspectives in the spatial planning process. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 437–442, ISSN 0749-0208.
Spatial planning can be seen as an interdisciplinary science that ensures sustainable development and land use, since it integrates policy, social, cultural, economic and environmental management issues. Marine and coastal spatial planning is particularly challenging due to their vulnerable, dynamic and complex nature and to the problems associated with sea level rise, erosion processes and land-use pressures in the coastal zone. Coastal erosion, flooding and shoreline retreat are serious problems along the coast of mainland Portugal. By using an innovative approach of coastal zone spatial planning, this study developed an Integrated Coastal Zone Management Plan for the Portuguese central region (stretch Ovar - Marinha Grande), where alternative planning policies to the previous ones were suggested. The study revealed that socio-economic analysis and the identification and valuation of ecosystems services and land use need to be incorporated in spatial planning to support decision-making favouring sustainable development. According to these approaches the Coastal Plan was developed considering three environmental scenarios to respond to the coastal erosion trends, based on a development model for the coastal region. In addition, the scenarios consider the public investments constraints (national budget) expected in the next decade and the short and medium term of the Plan. This Plan is differentiated from the previous by attempting to lessen further coastal erosion through the integration of different jurisdictions, legislations and directive measures and applying them to the terrain. This strategy shows itself as relevant to promote further forward-thinking Plans for other Portuguese coastal areas.
Monteiro, M.A.B, Oliveira, F.P., Araújo, J.N., Fernandes, M.E.B. 2014. Productive Chain of the Mangrove Crab (Ucides cordatus) in the Town of Bragança, in the Northern Brazilian State of Pará (Amazon Region). In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 443–447, ISSN 0749-0208.
The present study focuses on the production chain of the mangrove crab (Ucides cordatus), one of the key animal species in the mangrove forests of the Brazilian Amazon coast. The study began in the principal restaurants of the town of Bragança, in the northeastern extreme of the state of Pará, from which the principal components of the productive chain were identified, working back along this process until the primary producers, the crabbers, were detected. Questionnaires were applied each month throughout an annual cycle. The present study also identified the marketing processes (formal and informal) adopted by these social actors and analyzed the profit margins generated by the sale of the crabs at different stages in the process. All the social actors that compose this productive chain were monitored over an annual cycle. The Kruskal-Wallis nonparametric analysis of variance was used to evaluate the level of variation in the parameters analyzed. The results indicated that the U. cordatus productive chain in Bragança is composed of six social actors–crabbers, crabmeat pickers, primary and secondary traders, restaurants, and final consumers. While this chain is ramified, it is not complex, being formed by primary producers, wholesale and retail markets, and final consumers. All these levels are linked by the flow of capital, material, and information.
Negro, V., López-Gutiérrez, J.S., Esteban, M.D., Matutano, C., 2014. An analysis of recent changes in Spanish Coastal Law. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 448–453, ISSN 0749-0208.
Spanish coastal legislation has changed in response to changing circumstances. The objective of the 1969 Spanish Coastal Law was to assign responsibilities in the Public Domain to the authorities. The 1980 Spanish Coastal Law addressed infractions and sanctions issues. The 1988 Spanish Coastal Law completed the responsibilities and sanctions aspects and included others related to the delimitation of the Public Domain, the private properties close to the Public Domain, and limitations on landuse in this area.
The 1988 Spanish Coastal Law has been controversial since its publication. The “European Parliament Report on the impact of extensive urbanization in Spain on individual rights of European citizen, on the environment and on the application of EU law, based upon petitions received”, published in 2009 recommended that the Spanish Authorities make an urgent revision of the Coastal Law with the main objective of protecting property owners whose buildings do not have negative effects on the coastal environment.
The revision recommended has been carried out, in the new Spanish Coastal Law “Ley 2/2013, de 29 de mayo, de protección y uso sostenible del litoral y de modificación de la Ley 22/1988, de 28 de Julio, de Costas”, published in May of 2013. This is the first major change in the 25 years since the previous 1988 Spanish Coastal Law. This paper compares the 1988 and 2013 Spanish Coastal Law documents, highlighting the most important issues like the Public Domain description, limitations in private properties close to the Public Domain limit, climate change influence, authorizations length, etc. The paper includes proposals for further improvements.
Łonyszyn, P., Terefenko, O., 2014. Creation of an alternative season based on sustainable tourism as an opportunity for Baltic Sea Region. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 454–460, ISSN 0749-0208.
For several years, the Baltic Sea was divided by the Iron Curtain. However, though this situation changed over 20 years ago and this body of water has since become an internal sea of the European Union, there are still visible differences in the welfare and mentality of the people from the Baltic Sea Region. It's the world's largest body of brackish water, its beaches are exceptionally picturesque, and due to the concentration of iodine it is an exuberant source of medical richness. However, people view the coastal regions of the Baltic Sea countries almost exclusively as a destination for summer vacations. This results in the existence of an expansive, harmful tourist industry for a short time and distinct stagnancy throughout the rest of the year. The majority of local resorts from autumn to spring become examples of “ghost towns” where the inhabitants don't have regular incomes. The problem is, according to scholars, that extending the summer season is impossible in the Coastal Baltic Sea Region due to the local climate and economic conditions of the areas around the sea. The solution could be the creation of an alternative season based on sustainable tourism, as the extension of a summer season could only reduce the problem of the area's degradation due to mass tourism instead of solving it. This paper presents how an alternative season could be a real chance for a gradual end of the problem. Moreover, it shows real examples of transnational cooperation that could become the base for sustainable tourism in the Coastal Baltic Sea Region.
Catarina Fonseca, Carlos Pereira da Silva, Helena Calado, Fabiana Moniz, Chiara Bragagnolo, Artur Gil, Mike Phillips, Margarida Pereira, Miguel Moreira
Fonseca, C., Pereira da Silva, C., Calado, H., Moniz, F., Bragagnolo, C., Gil, A., Phillips, M., Pereira, M., Moreira, M., 2014. Coastal and marine protected areas as key elements for tourism in small islands. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 461–466, ISSN 0749-0208.
The Azores Archipelago (Portugal) is composed of 9 small islands located in the North Atlantic. To overcome the common challenges of this type of territory (e.g. isolation, closed systems, limited physical space and natural resources, endemism, small economies, small populations) and taking advantage of the natural and cultural heritage, the Regional Government of the Azores has based its Tourism Strategy on the high value of nature, landscape, flag species and outdoor experiences with a strong environmental friendly label. Pico Island offers the perfect scenario to enjoy such nature-based tourism activities, welcoming around 15,000 tourists per year, equivalent to the number of residents on the island. The island's natural and cultural heritage is outstanding and Pico Island Natural Park represents 35% of the territory, including several coastal and marine areas. Tourists' awareness about Pico protected areas, their activities and preferences can be extremely important to the management of the Island Natural Park. Integrated in the research project SMARTPARKS, a survey was conducted with 134 tourists, revealing the importance assigned to Pico protected areas and coastal zone. Among coastal and maritime activities, bathing and whale watching are the most frequent activities (57% and 44% of respondents, respectively) and 20% of respondents think whale watching should be promoted. This exploratory study gathered important information for decision-making agencies with respect to solving problems and possible solutions through tourism, namely the application of a fee system to help manage and conserve protected areas.
Yoshida, J., Udo, K., Takeda, Y., Mano, A., 2014. Framework for proper beach nourishment as adaptation to beach erosion due to sea level rise. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 467–472, ISSN 0749-0208.
Beach erosion caused by sea level rise is a serious problem for people over the world. Beaches play important roles in disaster prevention, recreational use, and nurturing unique ecosystems. Beach nourishment is capable of maintaining the position of the shoreline and the natural environment. However, applying artificial nourishment to the whole beach area is not a practical method due to high costs and the large quantity sand required. There has been no framework for effective adaptation of beach nourishment to solving coastal erosion issues. In this study, we focus on the beach nourishment as an adaptation to beach erosion due to sea level rise and attempt to construct a framework for proper beach nourishment. The framework for the adaptation proposal is as follows: (i) Prediction of shoreline changes and future beach width due to sea level rise; (ii) Determination of beach width to be protected in terms of disaster prevention, ecosystem conservation and recreation respectively; (iii) Specifying vulnerable areas where the area of and width of the beach Step; (iv) Estimation of sand volume and its cost applied only to the vulnerable area. This framework was applied to Japanese beaches where the determine beach width indicated that when a beach width of more than 10 m is needed for prevention against disasters, more than 20 m for ecosystem conservation, and more than 30 m for recreation use. The volume of sand required to maintain the beach width along the whole Japanese beach varies from 61× 106 to 2,300× 106 m3, and by the use of this framework, it is possible to estimate practical nourishment volume and its associated costs for disaster prevention, ecosystem conservation and recreation use.
Bouchette, F., Manna, M., Montalvo, P., Nutz, A., Schuster, M.,Ghienne, J.-F., 2014. Growth of cuspate spits. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70 pp. 047–052, ISSN 0749-0208.
The present work concerns cuspate spits: slightly symmetrical geomorphic features growing along the shoreline in shallow waters. We develop a new formulation for the dynamics of cuspate spits. Our approach relies on classical paradigms such as a conservation law to the shoreface scale and an explicit formula for alongshore sediment transport. We derive a non-linear diffusion equation and a fully explicit solution for the growth of cuspate spits. From this general expression, we found interesting applications to quantify shoreline dynamics in the presence of cuspate spits. In particular, we point out a simple method for the datation of a cuspate spit given a limited number of input parameters. Furthermore, we develop a method to quantify the mean alongshore diffusivity along a shoreline perturbed by well-defined cuspate spits of known sizes. Finally, we introduce a formal relationship between the geometric characteristics (amplitude, length) of cuspate spits, which reproduce the self-similarity of these geomorphic features.
Lam, N.S.N., Arenas, H., Brito, P.L., Liu, K.B., 2014. Assessment of vulnerability and adaptive capacity to coastal hazards in the Caribbean region. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 473–478, ISSN 0749-0208.
It has been documented that given the same type of climate related hazard and degree of exposure, the vulnerability of a region to the hazard and its resultant damages could be very different, depending on a number of natural and socioeconomic factors. An understanding of the factors contributing to the vulnerability of a region requires a good assessment method. This paper reports the results of a vulnerability assessment to hurricane hazards for the countries in the Caribbean region. The resultant index is a weighted combination of variables. The paper demonstrates a methodology to validate the weights of the variables used to compute the index through regression analysis with the storm damage data. The refined vulnerability indices for the 25 countries studied were found to range from 0.31 to 0.77. Small island countries were generally more vulnerable than large countries, with the highest vulnerability indices (>0.6) found in The Bahamas, Montserrat, St. Kitts and Nevis, and Turks and Caicos Is. Although the hurricane exposure was originally considered a key variable contributing to high vulnerability, low adaptive capacity in the form of low socioeconomic status, high electricity consumption, and low infrastructure development were found to have a higher weight contributing to the overall vulnerability index.
Magarotto, M., Costa, C., Tenedório, J.A., Silva, C.P., Pontes, T., 2014. Methodology for the development of 3D GIS models in the Coastal Zone. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 479–484, ISSN 0749-0208.
The present work involved a methodology which analyzes land use changes, from 1961 – 2011 using digital image processing and visual analysis of one satellite image and aerial photos. A simplified methodology using GIS 3D generates models of the coastal zone and its index of vertical growth. The GIS method uses SPRING - INPE (freeware) and ArcScence (ESRI). The data was obtained in the field (2011). The base area used was seventeen census sectors of the Brazilian Institute of Geography and Statistics (IBGE). To analyze vertical growth, a Volumetric Compactness Index (CVI) was created. It is able to track the tallest buildings over the years studied. The sectors were analyzed for spatial (N-S; E-W) and temporal (50 years) variations, where they were divided into North, Central and South zones of Boa Viagem. At all sectors occupation indexes are presently high, a strong trend of vertical growth exist that results in high volumetric compactness. Occupation and vertical growth are especially accentuated in the 1981–1996, reaching a maximum in 2011. Vertical growth increased from shore- inland being more prevalent towards the Central Zone, followed by the North and South. As a result of these processes, several problems arose with the most relevant including: impermeable coverings; large volumes of urban runoff; increasing temperatures; wind funneling; traffic jams; air pollution and; deficient water supply, wastewater collection and solid wastes collection. The results obtained using this methodology may be useful for the management of coastal areas and the potential for its development in relation to urban planning and development. The models obtained can prioritize mitigation actions in similarly developed neighborhoods.
Calado, H., Bragagnolo, C., Silva, S.F., Pereira, M. 2014. A multi-scale analysis to support the implementation of a regional conservation policy in a small-island archipelago – the Azores, Portugal. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 485–489, ISSN 0749-0208.
Small islands present both exceptional biodiversity and higher vulnerability. Their isolation has been identified as the main driver contributing to preserve the unique natural capital (10 of the 34 terrestrial biodiversity hotspots listed by Conservation International are wholly comprised of islands). However, small-island archipelagos may present a great variability among islands in terms of size and population, remoteness, incomes, natural and cultural landscapes, human pressures and vulnerabilities to global changes. This inexorably leads to different values, life-styles, and land use forms, which combine to shape cultural and socio-economic relationships of archipelagos, creating inter- and intra- island networks. Therefore, exploring inter- and intra-island relationships (based on historical, geographical, political and economic factors) can support a better understanding of networks and scale-dependent processes (ecological, economic, political, etc.), facilitating a more effective implementation of sustainable and biodiversity conservation policies at different levels. In this contribution, we present a multi-scale analyse to support the implementation of a regional conservation policy in a small-island archipelago (The Azores, Portugal). It represents a decision-making challenge for biodiversity conservation where a new management system of Protected Areas (PAs) was recently adopted. Three spatial units are considered: archipelago, island groups and island per se. The analysis integrates qualitative information, quantitative indicators and land use analyses in order to identify key areas of concern and relevant challenges for implementing the regional conservation policy at multiple levels. Findings underlined the importance to provide appropriate arrangements to better deal with scale mismatches arising from the divergence between spatial scale (where conservation challenges are identified) and administrative levels (where management interventions can be made).
Pupienis, D., Jarmalavičius, D., Žilinskas, G., Fedorovič , J., 2014. Beach nourishment experiment in Palanga, Lithuania. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 490–495, ISSN 0749-0208.
Palanga is one of the most popular Lithuanian seaside resorts, which has previously been valued for its wide beaches composed of light yellow fine-grained quartz sand. At the turn of the 20th and 21st centuries, intensified erosion processes in recreation zones led to shoreline retreat and the volume of beach sand reduced. Increased coastal erosion resulted in diminishing recreational space. In order to rebuild the eroded beaches, a decision to implement a beach nourishment project was made. From 2006 to 2012, through several stages along a 2.5 km stretch of shoreline, over half a million m³ of sand was added to the beach, dredged from the onshore Kunigi kiai sand quarry or offshore from the Baltic Sea floor. From 2004 to 2013, along the nourished stretch, coastal monitoring was carried out once a year in the spring; the beach's condition was assessed based on 10 cross-shore profiles: cross-shore levelling was carried out and sand samples were collected. On the basis of repeated cross-shore levelling, changes in the morphometric characteristics of the beach and dune ridges and sand volume were undertaken. Sand samples allowed the identification of its granulometric composition. The results showed that the shoreline has partially stabilised after the beach reclamation; the beach has become wider and higher, thus recreational conditions have partially improved, i.e. beach recreational space has increased. However, beach nourishment has not changed the coastal dynamic patterns. The beach is relatively stable due to the additional nourished sand. It should be noted that the morphometric parameters of the beach profile depend on the nourished sand volume. Due to the increased beach width, aeolian processes have intensified, resulting in an increased sand volume carried towards the coastal backdune forest. These shore reclamation operations have changed in the prevailing sand's granulometric composition. Previously, predominantly light yellow fine sand was replaced by dark brown medium sand. The beach restoration was the reason for an increase in beach slope.
Ferreira, M.A., Johnson, D., Pereira da Silva, C., 2014. How can Portugal effectively integrate ICM and MSP? In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 496–501, ISSN 0749-0208.
In 2013, the European Commission proposed a Directive to spur the integration of Maritime Spatial Planning (MSP) and Integrated Coastal Management (ICM) within and across Member States. To ascertain if key elements for integration exist, fundamental questions should be addressed: Are there (compatible) national policies/plans for the coast and ocean? Are ICM strategies in line with MSP policies? Are the agencies responsible for ICM and MSP coordinated? Are there common goals, indicators and integrated measures between both types of policies/plans? Portugal is one of the world's largest maritime nations, and is actively engaged in preparing policies and planning/management legislation for the ocean. An analysis of the current Portuguese policy/legislative framework, in terms of the above mentioned questions, suggested that: coordination among coastal and maritime policies and strategies is unclear, as is the articulation between institutions and between spatial plans for coastal and maritime zones; objectives of relevant policies are mismatched; there are yet no indicators to evaluate coastal and ocean policies/plans, and the articulation between measures to integrate ICM and MSP is unclear. Despite language barriers and people/institutional resistance to change, effective integration of MSP/ICM requires: flexibility and novel approaches, public participation and stakeholder involvement, systemic approaches, and finding strategic level indicators to evaluate integrated policies. Portugal can play a lead role in setting an example for other coastal nations worldwide. If appropriately tackled, the mismatches highlighted in this analysis provide pointers that may contribute to a more effective integration of ICM and MSP in Portugal and in other coastal nations.
Johnson, D., Lee, J., Bamba, A., Karibuhoye, C. 2014. West African EBSAs: Building capacity for future protection. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 502–506, ISSN 0749-0208.
The Convention on Biological Diversity (CBD)'s commitment to describe marine Ecologically or BiologicallySignificant Areas (EBSAs) through the organisation of a series of regional workshops has resulted in the collation and synthesis of relevant physical and biological datasets. Groups of typically 30–50 experts have pooled knowledge, with the support of technical facilitators, to undertake these intensive scientific and technical exercises in a growing number of marine regions around the world. The results, which are then subject to consideration by the Conference of the Parties to the CBD, describe areas meeting scientific criteria for EBSAs that may require enhanced conservation and management measures. For the South-East Atlantic (West Africa), such a regional workshop took place in Namibia 8-1 April 2013 and, subject to consideration by CBD scientific subsidiary body, the Conference of the Parties to the CBD should eventually be presented with a suite of descriptions of 45 areas meeting EBSA criteria in this region in October 2014 at its 12th meeting. This paper explains the processes that took place both before and after the West African Workshop. Firstly, the Sustainable Ocean Initiative (SOI) supported a first ever regional capacity building Workshop to facilitate the implementation of efforts towards Aichi Target 6 (sustainable fisheries) and 11 (marine protected areas), and to make connections between these targets and the EBSA process. This successful effort, held in Senegal in February 2013, prepared the ground for the subsequent EBSA Workshop. Experts became familiar with available data, with the challenges to be met and had an opportunity to exchange experiences. Sharing scientific information related to descriptions of areas meeting EBSA criteria toward achieving the Strategic Plan for Biodiversity 2011–2020 and Aichi Biodiversity Targets requires sustained effort and collaboration among various partners and experts. The Global Ocean Biodiversity Initiative (GOBI) brings together partners who can contribute skills and research results to inform this process. Areas meeting EBSA criteria in the South-East Atlantic region reflect transboundary connections – from river to sea, from inshore to offshore and deep-sea ecosystems. Ultimately their sustainable use should involve spatial area management tools including, where appropriate, an ecosystem-based approach to fisheries and networks of marine protected areas. The work of selected countries since the EBSA Workshop illustrates possibilities.
A. Oliveira, G. Jesus, J.L. Gomes, J. Rogeiro, A. Azevedo, M. Rodrigues, A.B. Fortunato, J.M. Dias, L.M. Tomas, L. Vaz, E.R. Oliveira, F.L. Alves, S. den Boer
Oliveira, A., Jesus, G., Gomes, J.L., Rogeiro, J., Azevedo, A., Rodrigues, M., Fortunato, A.B., Dias, J.M., Tomas, L.M., Oliveira, E.R. Alves, F.L., den Boer, S., 2014. An interactive WebGIS observatory platform for enhanced support of coastal management. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 507–512, ISSN 0749-0208.
A new WebGIS observatory platform is presented, tailored for risk assessment and emergency preparation and response in coastal areas. The tool combines a sophisticated forecast modeling system for multi-scale analysis of water bodies, including waves, hydrodynamics and oil spills prediction, with real-time monitoring networks for forcing and continuous validation purposes. Tailor-made visualization and analysis products, conceptualized for multiple uses through a service-oriented framework, provide an easy and interactive access to both data and predictions. The system was customized for oil spills risk assessment and the rapid response to an oil spill emergency, and applied to the Aveiro lagoon. The tool addresses oil spill problems in two complementary ways: 1) a detailed risk assessment through georeferenced hazard and vulnerability maps and GIS layers of information to support the definition of contingency plans; and 2) the visualization of georeferenced oil spill predictions produced by a real-time oil spill forecasting system. Improvements relative to existing risk systems are 1) the possibility of selecting quick-access predictions for fast emergency response or high-quality, georeferenced GIS prediction products, 2) the flexibility in accessing products to evaluate local impacts of oil spills both in the water column and in the intertidal areas, and 3) the enhanced hazard and risk analysis through a combination of a multi-scenarios approach with the historical database of spill predictions, forced by daily hydrodynamic forecasts. Dependability of information, for both model results and monitoring data, is being implemented through innovative ways, targeting the robustness and quality control of the WebGIS platform.
Guastella, L.A., Smith, A, M., Breetzke T., 2014. Coastal management and mis-management: comparing successes and failures at two lagoon outlets in KwaZulu-Natal, South Africa. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 513–520, ISSN 0749-0208.
KwaZulu-Natal (KZN) has a high energy, dynamic coastline. The coast is a significant asset, utilised for residential, industrial, transport, nature conservation and recreational purposes. It is also the discharge point for many steep gradient, short-headed rivers. These rivers have highly variable discharges and, together with variable coastal erosion and deposition cycles, place stress on coastal resources and infrastructure. Many of the rivers, particularly those with smaller catchments, discharge into back-beach lagoons before discharging into the ocean. Lagoon outlet dynamics are variable and, when combined with ocean swells and/or river flooding, can cause erosion. Coastal managers need to be aware of the risks to coastal assets and to this end, informed decision-making is vital to ensure sustainability of coastal resources and protection of coastal infrastructure, albeit often inappropriately located. While a strategy of non-intervention of lagoon outlets is always preferable, there comes a point when intervention may be necessary to protect coastal infrastructure, particularly if the intervention can replicate natural processes. Fixed coastal webcams, backed up by on-site photography, are used to illustrate two contrasting examples of coastal management on the KZN south coast at: (a) Margate where intervention resulted in the saving of coastal infrastructure, and (b) Amanzimtoti where a lack of intervention resulted in a train derailment, loss of infrastructure, injuries and significant repair costs. This paper critically reviews these contrasting examples and concludes that a greater understanding of lagoon outlet dynamics can significantly contribute to improved coastal management practices, and in this instance, could have prevented this derailment.
Alves, B., Benavente, J., Ferreira, Ó., 2014. Beach users' profile, perceptions and willingness to pay in Cadiz (SW Spain). In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 521–526, ISSN 0749-0208.
Beaches are complex systems on which different activities and interests are pursued. The most widespread activities relate to tourism and recreation. An individual's choice for a particular coast depends on the site characteristics and user's perception. In order to identify beach users' profiles and perceptions, a beach survey was carried out in the beaches of Cadiz, SW Spain, and subsequent sociodemographic factors affecting people's willingness to pay for beach management were identified. Despite part of the economic interests in Cadiz being related to tourism-related activities, most of the beach users are Cadiz residents. Respondents say that the elevated number of people in the beach during high season is problematic and causes unpleasant consequences, like accumulation of litter. Moreover, people mentioned the inadequate number of beach facilities (e.g. recreational services, showers, W.C.'s) and the perceived need for beach nourishment in some specific areas of the coast. The hypothetical implementation of a fee for beach management improvement was not supported by interviewees. A high number of local visitors of low economic status seemed to be the variables driving this finding. Regardless of beach users' assertions that the quality of the urban coast of Cadiz could be improved, they were not prepared to pay increased tax to achieve this.
Souza Filho, J. R., Santos, R. C, Silva, I R., Elliff, C.I., 2014. Evaluation of recreational quality, carrying capacity and ecosystem services supplied by sandy beaches of the municipality of Camaçari, northern coast of Bahia, Brazil. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 527–532, ISSN 0749-0208.
The coastal municipality of Camaçari is currently under great real estate pressure. It is located within one of the main urban growth vectors of the State of Bahia, Brazil. In this context, the main goal of this research was to assess the recreational quality and the carrying capacity, and qualitatively evaluate the ecosystem services supplied by the beaches of the municipality of Camaçari and its adjacent coastal area. In order to evaluate the recreational quality, the beaches of Busca Vida, Jauá, Interlagos, Arembepe, Barra de Jacuipe, Guarejuba and Itacimirim were classified according to twenty-three geoenvironmental quality indicators and eleven infrastructure indicators. Aiming to evaluate the similarity of geoenvironmental and recreational infrastructure characteristics among the studied beaches, a multivariate cluster analysis was used. The ecosystem services were assessed and gathered according to Regulation/Support Services, Provision Services and Information and Culture Services classes. Some beaches experienced a usage level above their carrying capacity, contributing to low geoenvironmental quality and compromising the supplied ecosystem services, mainly the ones concerning regulation and support. In beaches with low urbanization levels and predominance of natural or poorly human impacted environments, a greater diversification and quality of ecosystem services was identified, both of regulation and support services as well as of provision, information, culture and leisure services.
Cohn, N., Ruggiero, P., Ortiz, J., D.J. Walstra, 2014. Investigating the role of complex sandbar morphology on nearshore hydrodynamics. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 053–058, ISSN 0749-0208.
Coastal environments are characterized by complex feedbacks between flow, sediment transport, and morphology, often resulting in the formation of nearshore sandbars. In many locations, such as Hasaki (Japan), the Netherlands, and the Columbia River Littoral Cell (CRLC, USA), these sandbars exhibit a net offshore migration (NOM) cycle whereby these features form in the inner surf zone, migrate seaward and decay offshore on interannual cycles. Depending on the stage of the cycle, the number and configuration of the bars may differ widely. It has long been recognized that sandbars act as natural barriers during storm events by dissipating wave energy through breaking far from the beach face. Thus, dependent on the stage of the NOM cycle, one might expect significant variability in nearshore hydrodynamics. Using a non-linear wave model we demonstrate that inter-annual variability in sandbar configuration can significantly alter inner surf zone and swash zone processes. The model indicates that under different end-member NOM stages the same wave conditions can result in up to a 36% variance in the vertical extent of infragravity runup and can alter both the rate and direction of net cross shore sediment transport.
Lee, K.-H., Shin, S., Kim, D.-S., 2014. Cross-shore variation of water surface elevation and velocity during the bore propagation. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 533–538, ISSN 0749-0208.
In this study, we have investigated the hydrodynamics of a turbulent bore generated by removing a gate suddenly with water impounded on one side. This bore generation method was referred to a general dam-break problem. In order to perform the numerical simulation of the bore formation and propagation, we considered the incompressible flows of two immiscible fluids, liquid and gas, governed by the Navier-Stokes equations. The interface between the two fluids (air and water) was tracked by the volume-of-fluid (VOF) technique, and the M-type Cubic Interpolated Propagation (MCIP) scheme was used to solve the Navier-Stokes equations. It is known that the MCIP method is a low diffusive and stable scheme and is generally extended the original one-dimensional CIP to higher dimensions, using a fractional step technique. A Large Eddy Simulation (LES) closure scheme, which is a cost-effective approach to turbulence simulation, was employed to predict the evolution of quantities associated with turbulence. In order to verify the applicability of this numerical model to the bore simulation, the simulation results were compared to the laboratory experimental data. The numerical model for the bore formation and propagation based on the two-phase fully nonlinear Navier-Stokes equations was well verified by comparing with the analytic model based on the fully nonlinear shallow water wave equations and the laboratory experimental results.
den Boer, S., Azevedo, A., Vaz, L., Costa, R., Fortunato, A.B., Oliveira, A., Tomás, L.M., Dias, J.M., Rodrigues, M., 2014. Development of an oil spill hazard scenarios database for risk assessment. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 539–544, ISSN 0749-0208.
The occurrence of oil spills in coastal regions may have catastrophic consequences on the environment and severe socio-economic impacts. This work presents a new methodology to evaluate the risk associated with oil spills in coastal zones and estuaries, and illustrates its application in a coastal lagoon (Ria de Aveiro, Portugal). A ranked list of the hydrodynamic scenarios under which oil spills are most likely generated through the analysis of 33 years of wave and wind data, retrieved from the ERA-INTERIM project database, and from the analysis of oil spills that occurred in the Atlantic Iberian shelf. Considering six spill locations and a single oil type spill inside the Aveiro harbor, the database resulted in approximately 3500 simulations. Hydrodynamic simulations were made with the MORSYS2D modeling system, a soft coupling of the hydrodynamic model ELCIRC and the wave model SWAN. The high-accuracy, unstructured grid, oil fate model VOILS was used in 2D mode to simulate the transport and the oil weathering processes at the surface and in the intertidal areas. The hazard assessment analysis included the determination of the trajectory of the plumes, the shoreline retention areas affected by the oil and their oil exposure time. Time evolution of the oil properties, such as the oil evaporation rate and emulsification processes of the mixture, are provided to support clean-up operations, as well as robustness controls such as oil mass balance.
Sousa, R.C., Pereira, L.C.C., Costa, R.M. and Jiménez, J.A., 2014. Tourism carrying capacity on estuarine beaches in the Brazilian Amazon region. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 545–550, ISSN 0749-0208.
Tourism Carrying Capacity (TCC) can be defined as the level of human activity that an area can support without provoking deterioration of its physical and environmental characteristics. The present study aimed to estimate the maximum number of visitors that Colares, Marudá and Murubira beaches can receive during periods of peak visitation. The TCC was calculated considering the Physical Carrying Capacity (PCC), the Real Carrying Capacity (RCC), and the Effective Carrying Capacity (ECC) of each beach. In each survey, the number of visitors along a pre-established transect (central portion of each beach) was counted every hour (8 am until 6 pm). The maximum recommended ECC values indicated a maximum of 674 visitors per day at Colares, 812 visitors per day at Marudá and 97 visitors per day at Murubira. In comparison with these recommendations, the observed numbers of visitors were relatively high at Marudá (885 visitors) and Murubira beaches (297 visitors), while Colares was within the suggested limit (193 visitors). Peak visitation rates were recorded between 1 pm and 4 pm, and observed carrying values varied from 1.5 to over 5.000 m2 per visitor at Colares beach, 0.7–426 m2 per visitor at Marudá beach, and 1.7–42.9 m2 at Murubira. The results of the present study indicated that the density of visitors on the study beaches exceeded tolerable limits, and that coastal management measures are necessary to improve local tourist activities.
Zalewski, T., Czapiewski, T, 2014. The impact of processes associated with risk assessment and categorization of bathing waters on the water safety system development on Polish Baltic coast. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium(Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 551–555, ISSN 0749-0208.
The present paper attempted to systematize contemporary Polish water safety systems and create a preliminary evaluation of water safety system changes on the Polish Baltic coast using new legislation. The main focus is a risk assessment in the form of audits of bathing waters along with a categorization thereof. Detailed analyses included assessments of: the Act of 18 August 2011 –concerning the safety of persons in water–, administrators of the water area, entities authorized to perform water rescue, operational standards and reporting, monitoring with respect to dangerous bathing spots and drownings. An analysis is presented on the basis of 90 bathing sites and guarded areas used for swimming in the West Pomeranian Province in 2013, which is then compared with statistics from 2010–2012. With the number of drownings in the West Pomeranian Province compared to that of the accepted international standard discussed within the final part of the publication.
Botero, C., Pereira, C., Anfuso, A., Cervantes, O., Williams, A.T., Pranzini, E., Silva, C.P. 2014. Recreational parameters as an assessment tool for beach In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 556–562 ISSN 0749-0208.
Beach quality can be understood according to uses established for this coastal system, the most common being tourism, fishing and conservation. This is especially true with regards to tourism, where quality is frequently measured with respect to two major areas: environmental and recreational. In 2002, an environmental quality index for tourist beaches was developed in Colombia, called ICAPTU (Índice de Calidad Ambiental en Playas Turísticas). ICAPTU had four indicators and eleven parameters, mainly focused in environmental aspects. In 2010, a research project started with the objective of updating ICAPTU with a more comprehensive scope, dividing environmental quality into three indicators: sanitary, eco-systemic and recreational. This research paper presents the progress on the design of five parameters considered in the newer version of ICAPTU, all related to recreational issues: a. Coastal Scenery, focused on an assessment tool tested in Europe, USA and Australia; b. Safety and security, measured from risk perception and real risk; c. Urbanization, related to ecosystem resilience to infrastructure on the shore; d. Zoning, understood as a spatial organization of beach activities; e. Environmental behaviour, assessed from a test focused on common attitudes of tourists when they visit the beach. These five parameters were used on-field techniques as a method for acquiring information. Several instruments were designed based on surveys, checklists and interpretation sheets. Every tool was applied and tested on Colombian beaches located in four Departments: La Guajira, Magdalena, Atlántico and Bolivar. Geospatial technologies are also explored as resources for improving the evaluation of beach environmental quality. Finally, this work concluded that beach quality can be assessed by recreational parameters, scientifically designed, supporting decision making of coastal zone management.
A.-E. Paquier, S. Meulé, E.J. Anthony, G. Bernard, 2014. Sedimentation and erosion patterns in a low shoot-density Zostera noltii meadow in the fetch-limited Berre Lagoon, Mediterranean France. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 563–567, ISSN 0749-0208
Seagrass meadows fulfill several coastal ecosystem services that include coastal protection, provision of shelter for fishes and fish nesting sites, and water oxygenation. These aspects are hinged in part on the capacity of these meadows to attenuate waves and to slow down currents. Berre lagoon (area: 155 km²) is a fetch-limited, micro-tidal brackish water body on the French Mediterranean coast. At the turn of the 20th century, the lagoon was occupied by extensive meadows of Zostera marina and Zostera noltii. Urban and industrial pollution and freshwater diversion into the lagoon contributed to the complete disappearance of Zostera marina while Zostera noltii declined dramatically. Since the 1970s, these sources of perturbation have been drastically reduced but with no appreciable effect on Zostera noltii. A study was carried out on a receding Zostera noltii meadow occupying a small shallow bay (< 2 m deep) fronting a beach over a 14-month period in order to monitor both patterns of shoot density and erosion and accretion in the bay. Berre lagoon experiences short-fetch waves generated by northwesterly “Mistral” winds that exhibit a seasonal pattern. Shoot density shows a markedly seasonal trend that does not appear to be related to bed changes, which evened out over the study period. The data show that bed changes are less marked over the Zostera noltii meadow, and are more important in non-colonized areas, as well as along the beach, which exhibits sediment rotation. These patterns are probably reflecting the influence of the meadow on wave dissipation patterns.
Kure, S., Winarta, B., Takeda, Y., Udo, K., Umeda, M., Mano, A., Tanaka, H. 2014. Effects of Mud Flows from the LUSI Mud Volcano on the Porong River estuary, Indonesia. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 568–573, ISSN 0749-0208.
On May 29, 2006, mud and gases began erupting unexpectedly from a hydrocarbon exploration well near Sidoarjo, East Java, Indonesia. The eruption, called the LUSI (Lumpur Sidoarjo [Lumpur means mud in Indonesian]) mud volcano, has continued since then at rates as high as 180,000 m3 per day. The mud inundated an area in excess of 6.5 km2, in spite of attempts to contain it via the construction of a series of levees. The mud is erupting and accumulating behind the levee system. It is also being pumped into the Porong River, which then carries the mud to the ocean approximately 20 km to the east. The main objective of this study is to assess the effect of mudflow from the LUSI volcano on the river and estuary environment such as sediment deposition and water quality using the observed river cross sections and bathymetry data after the eruption of the LUSI volcano. From the analysis it was found that a significant sediment deposition occurred at the river bed of Porong River due to increased sediment discharge from the volcano during the dry periods after which the sediment deposits on the river bed were gradually eroded and flushed away to the ocean by floods and high water flows during the wet periods. Environmental impacts due to increased sediment from the Porong River on the estuary and coastal region are discussed.
Lopes, C.L., Dias, J.M., 2014. Influence of mean sea level rise on tidal dynamics of the Ria de Aveiro lagoon, Portugal. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 574–579, ISSN 0749-0208.
Global mean sea level rise is an important consequence of climate change because of its impact on coastal regions. Recent studies highlight that tidal propagation in shallow waters tends to be modified with mean sea level rise, intensifying coastal threats. This study aims to quantify changes in tidal patterns in Ria de Aveiro coastal lagoon, Portugal in response to the local mean sea level rise. To achieve this goal the hydrodynamic model ELCIRC, previously calibrated and validated for Ria de Aveiro, was applied, considering the present mean sea level and a local mean sea level rise projection of 0.42 m for the end of the 21st century, assuming no change in bed elevation. The model results for present mean sea level show that the amplitude of the main semidiurnal (M2) and diurnal (K1) constituents decrease whereas the respective phase increases towards the head of the estuary, while the M4 constituent shows an opposite pattern, due to the upstream lagoon shallowness. As consequence, the tidal distortion is higher in the lagoon upper reaches than at the lagoon mouth. Under mean sea level rise conditions, the tidal wave tends to be less distorted in the upper lagoon, given that the M2 amplitude tends to increase while the M4 amplitude tends to decrease. The results highlight that tidal current magnitude decreases toward the channel's head for both scenarios, but their magnitude tends to increase with mean sea level rise. The residual currents showed a net export of materials to the ocean, which will increase with mean sea level rise.
Markull, K., Lencart e Silva, J.D., Simpson, J.H., Dias, J.M., 2014. The influence of the Maputo and Incomati rivers on the mixing and outflow of freshwater from Maputo Bay (Mozambique). In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 580–585, ISSN 0749-0208.
Maputo Bay is a tidally-energetic embayment, influenced by strong rainfall and associated river runoff during the wet season. Literature shows that salinity can regulate the nutrient cycle in mangrove estuarine ecosystems affecting the early life stages in these habitats which sustain the economically important shrimp stocks. The freshwater flow into Maputo Bay is for a part controlled by dam systems on its main rivers. In this work we investigate how varying flows from the Incomati and Maputo rivers interact with the tide to influence the evolution of the bay's salinity field. A 3-dimensional hydrodynamic model was applied to Maputo Bay, improving a previously published model through vertical and temporal refinement and recalibration, leading to a more accurate representation of the semidiurnal and fortnightly stratification-mixing cycles occurring during the wet season. However, the model still predicts salinities lower than those found in observations. An analysis showed that uncertainties in the salinity field increased towards the mouth of the Maputo River indicating the uncertainty of the modeled flow at the catchment as a possible cause of the underestimation of salinity in the bay. A set of experiments of varying Maputo and Incomati river flows show that for a flow as frequent as 5 times per year, the buoyancy input and the associated density driven flow contributed less than the tide in forcing the bay-shelf exchange. The inverse is observed for results where a flow with a 5-year return period leads to a more efficient bay-shelf exchange during neap tides than during spring tides. For this scenario, the results suggest that the estuarine plume was arrested inside the bay by tidal stirring during spring tide and released during neap tide when tidal stirring was subdued. The analysis of the separate and joint effects of the two rivers in setting the salinity field in Maputo Bay show a difference in extent of influence area between the rivers. These results suggest that the management of the freshwater inflow from the Maputo River can be crucial for maintaining lower salinities over parts of the bay to sustain the economically important marine resources.
Tomas, L.M., Rodrigues, M, Fortunato, A.B., Azevedo, A, Leitão, P.C., Oliveira, A., Rocha, A., Lopes, J.F., Dias, J.M., 2014. Salinity modelling accuracy of a coastal lagoon: a comparative river flow analysis of basin model vs. traditional approaches. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 586–591, ISSN 0749-0208..
The main purpose of this study is to investigate the uncertainties in the modelling of salinity fields in the Ria de Aveiro lagoon associated with the estimation of river flow discharges. The prediction of fresh water inputs is necessary to properly implement forcing conditions and consequently to provide accurate forecasts of baroclinic circulation in coastal lagoons. Located in the north-western Portuguese coast, the Ria de Aveiro is a shallow vertically homogeneous mesotidal coastal lagoon with a complex geometry. Although it is tidally dominated, it receives freshwater from five rivers, the Vouga, Antuã, Cáster, Boco and Ribeira dos Moínhos, whose contributions are responsible for the salinity variation within the system. This research concerns the accurate prediction of river flow to be used in the operational forecast system of the lagoon. Given the lack of observed data for river discharges, as there are only two real time measuring stations located in the Vouga and Antuã river basins, but far from the lagoon, alternative estimation approaches are needed. In order to estimate the river discharges for all five rivers, two different approaches were considered: the first estimates the Vouga river flow, the major fresh water source, based on the nearest real time measuring station and estimates the other river flows based on river basin areas proportionality; the second establishes river flows based on the precipitation/river flow relationships for the Vouga and Antuã rivers and on the areas of the other river basins using the SWAT model. The methodology comprises the exploitation of the 3D unstructured-grid hydrodynamic model SELFE, required to adequately simulate the flow and transport of salt in very complex domains such as the Ria de Aveiro. The model is forced by water elevations at the ocean boundary and river flows at the river boundaries, and atmospheric drivers at the surface (wind stress, atmospheric pressure and heat fluxes). The salinity model predictions were compared with data from seven stations, and its accuracy was assessed through Root Mean Square Error (RMSE). The river flows estimated by the first method led to the best fit between observed and predicted salinity.
Dudzińska-Nowak, J., Wężyk, P., 2014. Volumetric changes of a soft cliff coast 2008–2012 based on DTM from airborne laser scanning (Wolin Island, southern Baltic Sea). In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 59–64, ISSN 0749-0208.
A comparison of DTMs off a 2 km-long section of the southern Baltic Sea cliff coast at Wolin Island, composed of unconsolidated Pleistocene sediments with NW exposure and maximum height of 93 m, prepared on the basis of airborne laser scanning (ALS) data collected in 2008, 2009, 2011 and 2012 allowed the magnitude and spatial distribution of changes to be determined. Morphodynamic processes were spatially and temporally diverse. The time period 2008–2012 is dominated by erosion expressed by a negative sediment balance of −33,000 m3. The volume of eroded material was 49,080 m3, while the volume of accumulated material − 15,678 m3. The largest changes were observed in the upper parts of active cliff as a result of mass wasting triggered by loss of the slope stability due to erosion of the lower part of the slope. Significant erosion also occurred on the lower part of the cliff and on the beach. The accumulation is a consequence of material deposition on the beach and at the cliff base. Erosion could be correlated with the number of storm events and with water levels. The results confirm previous studies on the role of factors that regulate the magnitude of coastal erosion, the first being water level rise during the storm events as well as the influence of a series of storms.
Villagran M., Caamaño D., Cienfuegos R., 2014. Hydrodynamics of a river-associated tidal inlet and maintenance of dynamic equilibrium: preliminary findings. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 592–597, ISSN 0749-0208.
Detailed video images and ADCP measurements were used to describe the processes of suspended sediment transport by the Mataquito River into the Pacific Ocean. It is found that, in the absence of fluvial flood discharges, suspended sediment transport to the sea only takes place during low tide periods and it is characterized by pulses of different frequencies that in turn are related to the spatial velocity distribution at the river inlet. It was observed that at low tide the highest velocities are near the mouth of the river, presenting an heterogeneous spatial distribution. In this high speed zone, we hypothesized the shear stresses are big enough to re-suspend fine sediment that is transported into the ocean by the main river current. A simple conceptual explanation based on these findings is presented, seeking to explain the observed dynamic equilibrium of the Mataquito River inlet after the significant alterations produced by the 2010 M8.8 earthquake and tsunami.
Lencart e Silva, J. D., Lopes, C. L., Picado, A., Sousa, M. C., Dias, J. M., 2014. Tidal dispersion and flushing time in a multiple inlet lagoon. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 598–603, ISSN 0749-0208.
The Ria Formosa is a tidal multi-inlet shallow-water coastal lagoon located in the south of Portugal, subjected to the dry Mediterranean climate. The tide controls the Ria's exchange with the adjacent shelf for most of the hydrological year except for isolated torrential run-off events. Episodes of low hypoxia reported in the literature may be related to the lagoon's flushing time, affecting its shellfish production valued at 20 – 50 million €y−1. Over the past decades several observational and modelling studies presented values for the capacity of the tide to renovate the water inside the Ria. However, these studies lack either the spatial resolution to yield results unaffected by numerical diffusion or analyze a very limited part of the lagoon's territory. In this work, we use a very-high resolution hydrodynamic model to assess the flushing time exclusively due to tidal forcing inside the Ria Formosa. A bi-dimensional implementation of the finite-volume/finite-difference Eulerian Lagrangian hydrodynamic and transport model (ELCIRC) was used, allowing for the local refinement of the computational domain, which best suits the lagoon's complex morphology. The present model configuration was validated for tidal propagation with sea surface elevation collected in 1979/80 at 11 lagoon stations. The validation results show a good agreement between predicted and observed elevations, with root mean square errors lower than 20 cm and skill values higher than 0.98. A set of experiments were carried out by releasing a conservative tracer at different stages of the tide at discrete points of the Ria, where possible environmental hazard hot-spots are located and the flushing e-folding time calculated from the tracer's dilution. The results are discussed taking into account the propagation of the tide in this multi-inlet, meandering topography. Evidence is presented of topographic trapping due to the complex spatial distribution of the phase lags of the semi-diurnal tidal constituents. This evidence explains the significant increase of the flushing time from the inlets to the head of the channels, thus justifying the use of detailed spatial resolution when modelling such a complex system.
Plecha, S., Picado, A., Chambel-Leitão, P., Dias, J.M., Vaz, N., 2014. Study of suspended sediment dynamics in a temperate coastal lagoon: Ria de Aveiro (Portugal). In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 604–609, ISSN 0749-0208.
Suspended sediment concentrations are simulated at Ria de Aveiro, a lagoon located in a temperate climate area in the northwest of Portugal. The fine-grained suspended sediment concentration is analyzed using the numerical model MOHID ( www.mohid.com) and spatial maps of instantaneous and maximum concentration and also temporal variability at specified locations are analyzed in order to characterize the influence of the tide and sea level conditions in the suspended sediment concentrations within the lagoon. The highest suspended sediment concentrations were found in upstream areas during ebb conditions due to the river's proximity, while the minimum concentrations were observed near the inlet due to the presence of marine water poor in suspended sediments. When a 0.42 m sea-level rise (an estimate of conditions in 2100) is modelled, a decrease in suspended sediment concentration is observed for the overall study area, as result of an increase in the tidal prism.
Vaz, N.,Dias, J.M., 2014. Residual currents and transport pathways in the Tagus estuary, Portugal: the role of freshwater discharge and wind. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 610–615, ISSN 0749-0208.
Estuaries are interface areas between rivers and the coastal sea. They also receive point discharges of contaminants which can affect estuarine biogeochemistry. The study of residual circulation in estuaries is a key issue since it is related to the transport and dispersal of dissolved and non-dissolved substances. This study investigates the residual flows in a coastal plain estuary (the Tagus estuary, Portugal) taking into account the major forcing factors: tide, river discharge and wind stress. The methodology used is the implementation of a high resolution estuarine model in a 2D mode to simulate the tidal dynamics of the estuary. Tidal flows were calculated by tidally-averaging the flow currents along the whole estuary. The complex bathymetry of the estuary, tides, river discharge and wind stress modulate the residual flow in the Tagus estuary. The combine effect of the tide and river discharge creates preferential corridor flows in the deeper areas of the estuary. On the other hand, wind intensity and direction generate changes in residual currents in the shallow areas near the south shore of the estuary. River runoff changes the residual current intensity from values higher than 0.3 ms−1 (high discharge) to values of about 0.05 ms−1 (low discharge). The wind direction also induces changes in the residual flow patterns, inducing a rotation of the residual flow, according to the wind direction. Thus, the estuarine model of the Tagus estuary is a tool that sheds new insight about its fundamental hydrodynamics processes and consequently about the long term circulation patterns.
Solari, S., Chreties, Ch., López, G., Teixeira, L., 2014. Analysis of the recent evolution of the sand spit at the Solís Chico river mouth. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 616–620, ISSN 0749-0208.
The Solís Chico river, located on the southern Uruguayan coast, flows into the Río de la Plata estuary. The seaside resorts La Floresta and Parque del Plata are located on the estuary. In recent years the river mouth has migrated westward, away from the river axis, forming a sand spit that hinders the recreational use of Parque del Plata beach. In turn, at La Floresta there is a beach nourishment project whose main objective is to mitigate the erosion of the beach and the adjoining cliffs. This work aims to identify the causes of the recent migration of the river mouth and to analyze the possibility of using the sand spit as a borrow area for the beach nourishment. The river sediment supply to the coast for the period 1900–2010 was estimated, along with the long-shore and cross-shore sediment transport produced by sea waves. Furthermore, the plan-view stability of the river was studied in order to determine if the long-term evolution of the river is affecting the migration of the mouth. It was found that the migration of the mouth is mainly due to an extraordinarily high river sediment supply in 2002, combined with an increase in the net westward potential long-shore transport rate since the late 90s, and that the meander dynamics of the river are not affecting the evolution of the mouth. Additionally, the most likely area of natural breaching of the sand spit was identified, recommending its use as a borrow area for nearby beach nourishment.
Benavente, J., Plomaritis, T.A., del Río, L., Puig, M., Valenzuela, C., Minuzzi, B. 2014. Differential short- and medium-term behavior of two sections of an urban beach. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 621–626, ISSN 0749-0208.
The present study aims to identify factors that control the different morphological evolution of two sections of an urban beach. The study area is the Victoria Beach in Cadiz city (SW Spain). The beach comprises two sectors: Cortadura zone (CZ) and Victoria zone (VZ), both subject to the same offshore wave conditions. The area is a typical low energy coast with dissipative beach morphology, where storm conditions are generally recorded in the winter season. Variability of beach profiles was analyzed through the use of empirical orthogonal functions (EOF). For short-scale processes, nearshore wave and current measurements were collected simultaneously at both zones during a tidal cycle. Additionally, medium term beach evolution from the last 50 years was evaluated using aerial photos. Results of medium term beach changes show a clear retreat that in fact led to several artificial nourishments of the beach over the last years. Erosion observed in CZ was greater than in VZ. In the short term, VZ presented greater morphological variability than CZ, which only experienced some changes in beach volume. Wave and current measurements showed a higher wave height and longshore current velocity in CZ under the same offshore wave conditions, which might account for the higher erosive trend in this area and development of a more dissipative profile. The reason for this differential behavior is related to the different characteristics of wave propagation in the outer surf and shoaling zone of both sections.
Li, B., Ellis, J. T., Sherman, D. J., 2014. Estimating the Impact Threshold for Wind-Blown Sand. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 627–632, ISSN 0749-0208.
In many aeolian studies, it is commonplace to use Bagnold's (1936) equation to calculate threshold shear velocity (u*t), which includes an empirical constant, A, typically set at about 0.082 for maintaining saltation (the dynamic, or impact, threshold). Here, we present data from a pilot study to assess the variability of A to improve estimations of u*t, which in turn, should improve transport rate predictions. Using field data from three coastal environments, we measured or calculated all parameters within the Lettau and Lettau (1978) model and u*t equation. In Jericoacoara, Brazil (BRA), Inch, Ireland (IRE), and Esposende, Portugal (POR) wind velocities were measured with cup anemometer towers and transport rates were measured using traps for 31 data runs lasting 120 to 1020 seconds each. Mean grain sizes were 0.17 mm (IRE), 0.31 mm (POR), and 0.30 mm (BRA), and mean shear velocities were 0.38 m s−1 (IRE), 0.40 m s−1 (POR), and 0.49 m s−1 (BRA). Empirically determined, adjusted A values ranged from 0.02 to 0.21 with a mean and standard deviation of 0.11 and 0.04. No relationship exists between estimates of A and grain Reynolds number. A statistically significant (p < 0.001), negative relationship was found between A and mass transport rate, leading to substantial over-prediction of transport rates near the threshold and under-prediction during fast winds if a constant of 0.082 is used.
Castelle, B., Almar, R., Dorel, M., Lefebvre, J.P., Sénéchal, N., Anthony, E.J., Laibi, R., Chuchla, R., du Penhoat, Y., 2014. Rip currents and circulation on a high-energy low-tide-terraced beach (Grand Popo, Benin, West Africa). In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 633–638, ISSN 0749-0208.
Rip currents are wave-driven intense seaward-flowing jets of water that are important to both beach morphodynamics and the overall ecosystem. Rip currents are also the leading deadly hazard to recreational beach users worldwide. More specifically, the African region is reported to have the highest rates of drowning in the world, yet both the occurrence and the type of rips developing along the African beaches are unknown. In February 2013, a 12-day field experiment was performed at the high-energy low-tide-terraced sandy beach of Grand Popo beach (Benin, West Africa). Human drifter data and video imagery are combined to address wave-driven circulation and rip current activity. Results show two prevailing rip current types. (1) Low-energy (~ 0.2–0.4 m/s) swash rips, with short life-spans of about 1 minute, extend about 5–10 m offshore and occur preferably at mid to high tide at fixed locations in the center of beach cusps. (2) Higher-energy (0.2–0.8 m/s) surfzone flash rips become active with the onset of intense wave breaking across the low-tide terrace. They tend to migrate downdrift with a longer time-span of about 2–5 minutes. The relatively weak longshore current (0.2–0.55 m/s) measured during the experiment suggests that flash rips were driven by vortices generated by wave breaking rather than shear instabilities of the longshore current. Swash rips and flash rips are common at Grand Popo and often co-exist. We propose a conceptual model of both flash and swash rip activity on this stretch of the West African coast.
Cienfuegos R., Villagran M. ,Aguilera J.C., Catalán P., Castelle B., Almar R,, 2014. Video monitoring and field measurements of a rapidly evolving coastal system: the river mouth and sand spit of the Mataquito River in Chile. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 639–644, ISSN 0749-0208.
The understanding of morphological processes controlling the evolution of sand spit reformation after a tsunami impact is a challenging and interesting topic, especially in highly energetic and micro tidal environments. A field campaign performed during December 2012 at the Mataquito River mouth in Chile, allowed us to simultaneously monitor topo-bathymetry evolution, wave climate, tidal range, swash zone dynamics and upper beach face evolution over a portion of its sand spit. A video system was set up for a continuous and long-term monitoring of the evolution of the river mouth and sand spit. Primarily, in this work we focus on the application of a video-derived shoreline detection method to assess shoreline evolution and beach cusps migration at hourly scales. We test the method performance on short-term episodic migration of beach cusps recorded during the campaign. Beach face variations at a daily scale were observed, which can be attributed to the migration of beach cusps in the alongshore direction, and linked to wave forcing and alongshore sediment transport.
Poate, T.G., Masselink, G., McCall, R.T., Russell, P.E., Davidson, M.A., 2014. Storm-driven cusp behaviour on a high energy gravel beach. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 645–650, ISSN 0749-0208.
Gravel and mixed sand-gravel beaches are characterised by steep reflective profiles which provide effective forms of wave absorption and therefore coastal defence to many mid-latitude regions, including northwestern Europe and North America. In the UK the combination of energetic wave conditions and large tides creates very dynamic and responsive morphology often dominated by cuspate features. Recent storm-responsive field campaigns at Loe Bar, Cornwall, UK, have captured highly energetic wave conditions (Hs = 2.5–5.8 m) using temporary video camera installations, low tide 3D topographic surveys with real time kinematic GPS, local tide level measurements and inshore directional wave data. Characterised by fine gravel (D50 = 3 mm) and a steep reflective profile (tanβ = 0.118), the barrier at Loe Bar is exposed to an annual 10% exceedence significant wave height Hs10% of 2.4 m arriving predominantly from the southwest (Atlantic Ocean) and shore-normal to the beach. Under medium-wave conditions (Hs = 2–3 m), contrasting cusp behaviour was recorded with accretion and erosion, principally, through horn growth and decay (bed-level change Δz = c. 1 m). During more energetic conditions (Hs = 5.8 m), the morphological response is more consistent and the waves drive erosion of the lower profile causing bed-level changes over a tide in excess of 1.5 m. Very rapid recovery to pre-storm bed levels is observed with defined cusp evolution occurring within 12 hours during the falling limb of the storm as incident wave energy decreases. The unique gravel cusp dataset suggests free behavior due to cusp morphodynamic feedback, rather than hydrodynamic forcing, plays an dominant role in cusp evolution.
Ab Razak, M.S., Dastgheib, A., Suryadi, F.X., Roelvink, D. 2014. Headland structural impacts on surf zone current circulation, Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 065–071, ISSN 0749-0208.
The paper presents the morphodynamic investigation of embayed beaches through the impact of structural headlands. An XBeach model was successfully applied to predict the surf zone current pattern and to predict morphological features of three different embayment scales for low-moderate-high wave energy events. The formation of central rip currents in embayed beaches is linked to the presence of a sand bar, while topographical headland rips developed adjacent to the headland boundary are caused by the geological control of the headland structure itself. The effect of moderate and high waves has resulted to a decreased number of central rips in a longer embayment thus limiting the beach circulation to the cellular type. This type of rips could provide an initial insight into the offshore transport of sand from the coast. Whether wave breaking occurs outside or inside the embayment determines the initiation of large scale rip currents, megarips. Several factors that lead to the generation of megarip currents in literature should be taken into account as a guideline for morphodynamic studies in a high energy embayed coast. Nevertheless, the characteristics of surf zone current circulation in all cases presented in this study complies with the description of the theoretical embayment scaling parameter (δ') (Short and Masselink, 1999 and Castelle and Coco, 2012). Further establishment of this parameter is needed to properly describe the surf zone current circulation in embayed beach systems.
Almar, R., Hounkonnou, N., Anthony, E., Castelle, B., Senechal, N., Laibi, R., Mensah-Senoo, T., Degbe, G., Quenum, M., Dorel, M., Chuchla, R., Lefebvre, J-P, du Penhoat, Y., Laryea, W.S., Zodehougan, G., Sohou, Z., and Appeaning Addo, K., Kestenare, E., 2014. The Grand Popo beach 2013 experiment, Benin, West Africa: from short timescale processes to their integrated impact over long-term coastal evolution. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 651–656, ISSN 0749-0208.
The first large nearshore field experiment in the Gulf of Guinea was conducted at Grand Popo Beach, Benin, in February 2013, on an open wave-dominated micro- to meso-tidal coast, located mid-way between Cotonou and Lome harbours. The overall project aims at understanding at multi-scale (from event to interannual) the causes of the dramatic erosion observed throughout the Bight of Benin, and caused by the interaction of a large littoral drift with human engineering works. Grand Popo 2013 experiment was designed to measure the processes over the short term and to test the ability of an installed video system to monitor the evolution of this stretch of coast over the longer term. The beach, characterized by a low-tide terrace and a high tide reflective part, experiences a long swell (Hs=1.6 m, Tp=16 s, oblique incidence ~15–20°). Topographic surveys showed a double beach cusp system interaction and repeated surf-zone drifter runs revealed high flash and swash rip activity driven by wave dissipation over the terrace and energetic swash dynamics at the upper reflective beach. Swash was measured over a cusp system at two locations using video poles. Wave reanalyses (ERAInterim) were used to determine the wave climate and its variability, and to quantify sediment transport. This robust methodology is thought to be replicated elsewhere in different coastal environments in West Africa, in particular with the objective to monitor various sites within the framework of the new West African Coastal Observatory.
Hoonhout, B.M., Baart, F., Van Thiel de Vries, J.S.M. 2014. Intertidal Beach Classification in Infrared Images. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 657–662, ISSN 0749-0208.
Digital imagery is a powerful data source for coastal monitoring, maintenance and research. It provides high-resolution measurements in both time and space. The size and resolution of long-term imagery datasets provide great opportunities, but also pose problems of tractability in the data analysis. In order to fully use the possibilities of these datasets, reliable and automated classification of images is essential. This paper discusses an automated classification approach based on Conditional Random Fields (CRF). The algorithm is applied in pixel space only. Therefore it does not rely on in-situ measurements, nor is there a need for image rectification. The algorithm consists of three steps: segmentation, feature extraction and model training and prediction. We applied the method to a coastal thermal infrared image stream that monitors the wetting and drying of the upper intertidal beach in relation to tide and meteorological parameters. Classification of the upper intertidal beach provides information on the potential sources of Aeolian sediment. The use of 62 extracted features and structured learning proves to provide significantly better classification results compared to algorithms solely based on intrinsic intensity features.
Lefebvre, J.-P., Almar, R., Viet, N.T., Uu, D.V., Thuan, D.H., Binh, L.T., Ibaceta, R., Duc,N.V., 2014. Contribution of swash processes generated by low energy wind waves in the recovery of a beach impacted by extreme events: Nha Trang, Vietnam . In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 663–668, ISSN 0749-0208.
Nha Trang beach experiences southerly sediment drift during winter monsoons and northerly sediment drift during summer monsoons. In addition, the area is likely to be impacted by tropical storms or typhoons. Due to the presence of islands at the south east border of the bay, the strongest impact on the shoreline apart from extreme events is due to NE swell from October to April. The mechanism responsible for the sediment drift generated by low energetic locally generated wind waves is insufficiently understood. It involves the functioning of the swash zone for weak conditions. Two field experiments were scheduled before and after the period of cyclonic activity. The aim of the first experiment was to describe the site's bathymetry and the geomorphology of the upper beach and hydrologic functioning of the bay. A new method of measurements in the swash and surf zone based on processing of data extracted from HD video processing was tested successfully for wind wave conditions in a reflective beach. Here, we present some data obtained during the field experiment at different time scales. The data provides a first quantification of the impact on sediment transport from typical low energy conditions which are encountered during spring and summer in Nha Trang.
Senechal, N., Laibi, R.A., Almar, R., Castelle, B., Biausque, M., Lefebvre, E. J. Anthony, J.-P., Dorel, M., Chuchla, R., Hounkonnou, M.H., Du Penhoat, Y., 2014. Observed destruction of a beach cusp system in presence of a double-coupled cusp system: the example of Grand Popo, Benin. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 669–674, ISSN 0749-0208.
Beach cusps are common features of steep reflective and intermediate beaches. However, very few observations have reported double coupled cusp systems. Here, we present a dataset of observations of a beach exhibiting two sets of beach cusps. Data were collected at Grand Popo Beach (Benin, West Africa) in February 2013. Daily topographic surveys along a 380 m long stretch of shore allowed observation of the dynamics of the two sets of beach cusps. At the beginning of the field survey, we clearly observe two sets of cusps; the upper beach cusps system is relatively asymmetric with a typical wavelength of about 45 m, while the lower beach cusps system is relatively symmetric with a typical wave length slightly shorter (about 35 m). After two days, we measured the total destruction of the lower set of beach cusps while the upper set of beach cusps was only partially destroyed. The data suggest that destruction of the lower beach cusp system may be related to persistent accretionary conditions and/or calm conditions but probably also to the transition from wave-driven circulation (dominated by weak alongshore currents with flash and swash rips), to a second period characterized by dominant longshore currents further increasing in speed (with rare swash rips). Conversely, the disappearance of the western upper beach cusp may be related to an accretionary pattern and to the coalescence of two individual features. Our observations, consistent with previous works, suggest that beach cusps certainly arise as a result of some combination of erosion and accretion.
Matias, A., Carrasco, A.R., Loureiro, C., Almeida, S., Ferreira, Ó., 2014. Nearshore and foreshore influence on overwash of a barrier island. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 675–680, ISSN 0749-0208.
Accurate prediction of the occurrence and morphological consequences of overwash are important for coastal flood risk assessment and management. A number of morphological and oceanographic factors controlling overwash have been identified by several authors, including nearshore bathymetry. This work intends to identify alongshore variations in storm impact and evaluate the role of sub-aerial and submerged morphological variations in overwash occurrence. For this study, 24 cross-shore topo-bathymetric profiles were set on Barreta Island (Ria Formosa barrier island system, Portugal), extending from the nearshore to the lagoon level on the island backbarrier. Pre- and post-overwash surveys were made between August 2012 and April 2013. Offshore wave characteristics were obtained during overwash events including offshore significant wave height (Hs), peak period and wave direction. Wave propagation and wave parameters at breaking were obtained from SWAN model simulations. During the study period, overwash occurred both under storm conditions (e.g., Hs = 3.8 m) and non-storm conditions (e.g., Hs = 0.8 m), the latter coincident with spring high-tide. Overwash water intrusion distance across the barrier varied alongshore between 0 m (no overwash) and 40 m (reaching lagoon waters). Beach morphology was spatially variable, and changeable from one overwash episode to the next. Important morphological variations of the barrier include modification of barrier crest elevation, beach slope, and presence of swash bars in the vicinity of Ancão Inlet. Predictions of overwash occurrence were made by means of the computation of the Overwash Potential (OP), defined as the difference between the wave runup and the barrier elevation. Several runup equations were tested, and the results of obtained OP were compared to the observations of actual overwash occurrence to determine the most reliable approach. The selected predictor provided an accuracy of 88% for the identification of the locations where overwash processes occurred along the barrier. The predictions were variable alongshore due to variations in breaking waves and beach slope, which in turn are related to the existence of nearshore bars, associated with the presence of the updrift Ancão Inlet. This study proves that nearshore and foreshore morphologies have a major impact on the longshore variation of overwash distribution.
Pereira, L.C.C., Pinto, K.S.T., Vila-Concejo, A., 2014. Morphodynamic variations of a macrotidal beach (Atalaia) on the Brazilian Amazon Coast. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 681–686, ISSN 0749-0208.
Beach morphology, waves, tides, and current speeds were measured in a moderate-energy macrotidal environment of the Amazon coast (Atalaia beach, Brazil). The study was based on two complementary sets of data: (i) hydrodynamic and topographic data collected in four 25-hour campaigns during equinoctial and non-equinoctial periods, and (ii) climatological data (wind speed and direction, and rainfall) obtained from the Brazilian Institute of Meteorology. The results indicate that tidal currents run predominantly to the northwest during the flood tide and southeast during the ebb. The highest current speeds were recorded during the equinoctial period, reaching a maximum of 0.5 m/s in the flood tide. In March and June (rainiest months), ebb tide currents reached a maximum speed of 0.4 m/s. The tidal cycle was weakly asymmetric with the ebb tide lasting up to 6 hours and 40 minutes. High tides ranged from 4 m (non-equinoctial) to 5.7 m (equinoctial). Wave energy was modulated slightly during the low tide due to wave attenuation on the sandbanks, but substantial changes were not observed during ebb and flood tides. Modal wave height (Hb) varied from 1.1 to 1.43 m, associated with wave periods of 5.0–7.5s, with the highest values being recorded in November (intense winds). This beach can be classified as tide-modified, presenting primarily dissipative (Ω > 5) characteristic. Wave-dominated characteristics were observed in November, when Hs values were around 1.5 m and tidal elevation was approximately 4 m (non-equinoctial period).
Barboza, E.G., Rosa, M.L.C.C., Dillenburg, S.R., Biancini da Silva, A., Tomazelli, L.J., 2014. Stratigraphic analysis applied on the recognition of the interface between marine and fluvial depositional systems. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 687–692, ISSN 0749-0208.
Coastal areas contain interfaces between complex depositional systems as a consequence of the convergence of marine and continental environments. The knowledge of such complex depositional systems is important in understanding of coastal evolution and for coastal management. The present study deals with the subsurface identification of interfaces between fluvial and beach/shallow marine systems, using Ground Penetrating Radar (GPR). GPR profiles were measured along dip direction, at two sites on the coastal plain of Santa Catarina state (Pinheira and Passo de Torres), where deposits of fluvial and beach/foredune ridge systems occur. GPR data showed that fluvial and beach deposits are interdigitated in subsurface, with reflectors showing different downlap directions. The results of this study allow a more complete knowledge of the complex interfaces between marine and continental systems. Also, the identification of hidden older fluvial deposits in the subsurface of coastal plains gives important geotechnical information to be considered in the use and occupation of coastal areas and during prospection for placer deposits.
Tătui, F., Vespremeanu-Stroe, A, Preoteasa, L., 2014. Alongshore variations in beach-dune system response to major storm events on the Danube Delta coast. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 693–699, ISSN 0749-0208.
Deltaic beach-dune systems are extremely dynamic, responding to processes operating on scales from short-term variations related to storm and floods to long-term evolution driven by large-scale sediment dynamics (including lobe switching). On Danube Delta beaches, coastal storms and associated processes lead to a wide range of morphological impacts from moderate deposition to significant erosion. Coastal processes develop with marked temporal differences as a result of variations in storminess related to changes in climatic systems (North Atlantic Oscillation). In order to assess the variations in vulnerability to extreme storms, different sectors along the study site were examined using two storm impact indexes: Storm Impact Categories of Sallenger, 2000 and Dune Stability Factor of Armaroli et al., 2012, based on specific storm thresholds. There is a very good correspondence between the effects of the December 1997 – January 1998 extreme storm cluster and the vulnerability of the beach-dune system predicted with both indicators, with significant alongshore variations of storm impact. The driving factors imposing this variability at different time scales are also discussed, ranging from nearshore slope (which imposes different wave heights and storm induced water level increase) and sediment availability (in direct connection with the evolution of different deltaic lobes, position into the littoral cell and the distance to the Sf. Gheorghe arm mouth, river discharge variability and human interventions) to beach-dune morphology (accommodation space and pre-existing coastal morphology).
Fernández Lázaro, A., Gutiérrez Serret R.M., Negro, V., López-Gutiérrez, J.S., 2014. Analysis of wave attenuation and shore protection of a bulk carrier ship performing as a detached floating breakwater. Proceedings of the 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 007–012, ISSN 0749-0208.
The effectiveness of a bulk carrier working as a detached floating breakwater to protect a stretch of coast and form salients or tombolos is assessed in this paper. Experiments were conducted in the Madrid CEDEX facilities in a 30 m long, 3 m wide, 1/150 scale flume. The bulk carrier ship is 205 m long, 29 m wide and 18 m in height with a draught of 13 m, and has been subjected to irregular waves with significant heights from 2 m to 4 m and peak periods from 6 s to 12 s at a depth of 15 m, all prototype dimensions. Three probes were placed between the wave paddle and the ship to record incident and reflected waves and four probes were placed between the ship and the coastline to measure the transmitted waves. Transmission, reflection and dissipation coefficients (Ct, Cr, Cd) were calculated to determine wave attenuation. Results show good shelter in the lee of the ship with values of Ct under 0.5 for peak periods from 6 s to 11 s. In addition, forces on the mooring chains were measured showing maximum values of about 2000 tons at a 10 s peak period. Finally, two analytical models were used to determine the shoreline's response to the ship's protection and to assess the possible forming of salients or tombolos. According to the results, salients - but not tombolos - are formed in all tests.
Thorpe, A., Miles, J., Masselink, G., Russell, P., 2014. Bedform Dynamics in a Rip Current, Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 700–705, ISSN 0749-0208.
A Sand Ripple Profiler (SRP) was deployed in a rip channel on a dissipative sandy beach to measure bedform height (Δ), length (λ) and migration rate (Mr) throughout a macro-tidal cycle.
Data were collected in significant wave heights ranging from 0.5 m to 2.1 m and water depths of between 0.9 m and 7.4 m. Periods when the rip current was active were identified by comparing measured cross-shore velocity (U) with predicted cross-shore velocity from a bed return flow model. Rip flow was found to commence when offshore velocities reached approximately 0.1 m/s, maximum rip velocity as a 5 minute mean was 0.74 m/s. At lower tidal elevations (h < 2.5 m), in the strong offshore flow of the rip current megaripples were found to migrate offshore (Mr = 0–4 cm/min). When migration occurred in a rip current migration rates were correlated with U with the highest migration rates found in the strongest flows.
In non-rip current conditions megaripples exhibited two types of migration behaviour; (1) migrating onshore at a maximum rate of 2.1 cm/min when h was in the range of 2.5 m to 5 m and wave skewness was high and (2) megaripples were stable when mean flows and skewness were low, this occurred at higher tidal elevations when h > 5m.
Terefenko, P., Terefenko, O., 2014. Determining the role of exposure, wave force, and rock chemical resistance in marine notch development. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 706-711, ISSN 0749-0208.
In order to assess the role of coastal exposure, wave force, and rock chemical resistance in marine notch development a study was undertaken along 28km of the Algarve region in southern Portugal between Gale and Portimao. Notches were identified in the field, and exposure to wave force was calculated on the basis of wave refraction estimates. Almost 100 samples were collected and analyzed to assess calcium carbonate content of the coastal lithology. Finally with the use of GIS geostatistical methods, values of chemical resistance were calculated. Statistical correlation analysis enabled the definition of the importance of each investigated factor in the process of the formation of marine notches and the resulting shape. Since shape is a quantitative factor, several additional statistical calculations such as the Kruskal-Wallis test and analysis with tree classification methods were performed. The final results show that the importance of each factor controlling coastal morphology is changeable and depends generally on coastal exposure. Bigger wave force is assisted with lower diversity of coastal forms. The shape of the coastal notches depends on the notch exposure and wave force. The bigger the wave force the higher the probability that V-shape notches occur. The effect of the chemical resistance factor was less prominent though it does influence notch shape at specific levels of wave force.
Short, A.D., Bracs, M.A., Turner, I.L., 2014, Beach oscillation and rotation: local and regional response on three beaches in southeast Australia. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue 70, pp. 712-717, ISSN 0749-0208.
Six years of monthly subaerial surveys across three embayed beaches in southeast Australia located 270 km apart are utilized to compare the response of the beaches at the local and regional scale. The three beaches (Narrabeen, Moruya and Pedro) are exposed to a similar deep water wave climate (Hs ~1.5 m, T~10 s), identical tides (spring range 1.6 m) and have similar lengths (~3 km), easterly orientation and medium to fine sand. Over the six years all three beaches had synchronous oscillation and rotation, though at different magnitudes. The lower energy Moruya beach undergoes greater beach oscillation (up to 100 m) and rotation than the higher energy Narrabeen and Pedro. The results highlight the regional scale of synchronous beach response, as well as have implication for our understanding of sediment transport and shoreline stability in relation to beach state, with the lower energy beach having a more dynamic shoreline. Furthermore the six years of data is insufficient to detect longer term trends observed at Narrabeen since 1976.
Jackson, D.W.T.., Cooper, J.A.G., Green, A.N., 2014. A preliminary classification of sand dunes of the KwaZulu-Natal coast. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 718–722, ISSN 0749-0208.
The 550 km-long KwaZulu-Natal coast broadly divides into a bedrock-framed southern section and northern coastal plain section, each of approximately equal length. Seven types of coastal dune are identified on this coast: estuary barrier dunes; mainland beach foredunes; prograded beachridge dunes; headland bypass dunes; transverse dune fields; parabolic/migrating dunefield; and climbing dunes. The development and distribution of the various dune forms is more strongly controlled by the geological setting, than the aerodynamic regime.
Thomas, T., Lynch, S.K., Phillips, M.R., Williams, A.T., Duck, R.W. 2014. Relationships between sand spit evolution, environmental forcing and inland inundation.In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium(Durban, South Africa),Journal of Coastal Research, Special Issue No. 70, pp. 072–077, ISSN 0749-0208.
Topographic field data and environmental forcing agents were used to assess morphological changes (1995–2010) at Ginst Spit, Pendine Sands, West Wales and flood potential at Laugharne, a town in the lee of the spit. Areal change between annual surveys showed variable distal end migration eastward extending into the channel of the Towy, Taf and Gwendreath estuaries. Dominant waves emanate from south toward southwest and suggest that the longshore sediment drift is from west toward east. However, sub-dominant waves from southeast are limited by fetch but engender a counter drift back toward the west at the distal end forming the customary northward hook.Wave model results showed significant modifications occurred between the inshore model boundary and the nearshore zone and overall results suggest that spit evolution is dependent on sediment movement that occurs during high spring tidal conditions within this macrotidal environment. Precipitation and flood events were correlated to spit evolution, which suggested that a combination of fluvial and coastal processes in combination contribute to the flooding of Laugharne town.
Switzer, A.D., Yu, F., Gouramanis, C, Soria, J, Pham, T.D. 2014. An integrated approach to assessing coastal hazards at multi-century timescales. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 723–728, ISSN 0749-0208.
In many places on earth, the written record of coastal flooding events from tropical cyclones (typhoons, hurricanes) and tsunamis is too short or inconsistent to accurately assess the hazard posed by both kinds of event on scales beyond those of the average human lifespan. In this paper we summarize an integrated research paradigm that incorporates instrumental, historical, archaeological and geological records to extend the record of coastal flooding events to generate a multi-century analysis of recurrence interval for coastal flooding, thus, improving long-term risk assessment. The two primary factors in assessing risk from coastal hazards are frequency and magnitude. These can be addressed through field and modeling studies of washover deposits where they are found. We also summarize recent advances in the identification of overwash events from the geological record and report on the progress to distinguish storm and tsunami deposits. The recent advances have increased the utility of tsunami and storm deposits to improve coastal risk assessment.
Zikhali, V., Tirok, K., Stretch, D., 2014. Wind-driven waves in a shallow estuarine lake with muddy substrates: St Lucia, South Africa. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 729-735, ISSN 0749-0208.
Wind-waves in shallow lakes or estuaries with muddy substrates can drive sediment re-suspension and cause high turbidity levels that can negatively impact the productivity of photosynthetic organisms. This investigation evaluates the efficacy of a simple semi-empirical model (Young and Verhagen, 1996 : Coastal Engineering, 29, 47–78) for predicting the wave characteristics in these systems in order to include their effects in ecosystem models. The southern basin of the St Lucia estuarine lake in South Africa was used for a case study. Average depths are about 1 m with fetches up to approximately 10 km. Substrate materials vary from sandy to muddy with deeper locations predominantly the latter. An array of pressure sensing wave poles was deployed to measure significant wave heights and periods to compare with model predictions. The influence of the wind speed, fetch, fetch-averaged depth, and substrate composition were evaluated. Most of the observed waves were fetch limited during the conditions that prevailed during the two field trips. The results indicate that the model adequately captures the high energy wave events for persistent wind speeds and directions, but that there is considerable variability in its performance generally. Some of this variability can be attributed to difficulties in estimating appropriate fetch and depth parameters for variable winds and in the context of a lake with compound shape and variable bathymetry. There was no clear evidence of significant wave attenuation due to the muddy substrates.
Kelly, C.S., Green, A.N., Cooper, J.A.G. and Wiles, E. 2014. Beachrock facies variability and sea level implications: a preliminary study. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 736–742, ISSN 0749-0208.
In spite of the worldwide abundance of beachrocks and their acknowledged utility as an indicator of former sea level position, some studies have expressed doubt as to their position of cementation on paleo shorelines. These criticisms are not, however, coupled with nuanced sedimentological studies of beachrocks. Instead, few beachrock studies acknowledge any facies and therefore disregard important signatures of the depositional environment and, consequently, utility as paleo sea level indicators. This study presents detailed sedimentological descriptions and interpretations from two beachrock localities along the subtropical, microtidal, wave-dominated eastern coastline near Durban, South Africa. The outcrops record the migration of a paleo inlet and deposition in sub, inter, and supra tidal environments. Understanding the inferred depositional environment, and observed stratigraphic relationships between various beachrock facies is critical to teasing out the local evolution of shoreline and relative sea level. The outcrops studied here record multiple episodes of Holocene sea level rise and fall.
Laïbi, R. A., Anthony, E. J., Almar, N., Castelle, B., Senechal, Kestenare, E., 2014. Longshore drift cell development on the human-impacted Bight of Benin sand barrier coast, West Africa. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 078–083, ISSN 0749-0208.
The Bight of Benin is an open, microtidal, wave-dominated coast forming a 500 km-long mild embayment in the Gulf of Guinea, in West Africa, between the Volta River delta in Ghana, to the west, and the western confines of the Niger River delta in Nigeria to the east. The bight is exposed to energetic swells from the South Atlantic, and is characterised by Holocene sand barriers bounding lagoons. The barrier system has been sourced essentially by sand supplied through the Volta River delta, terminus of a large river catchment of 397,000 km2, although wave energy conditions and sand mineralogy also suggest inputs from the nearshore shelf. The long-term pattern of barrier progradation in the Bight of Benin culminated in a mildly embayed coast wherein incident wave behaviour, beachface gradient and the longshore sand transport system were intimately linked, generating what may be classified as an ‘equilibrium drift-aligned’ coast with a unique and homogeneous longshore drift cell stretching from the Volta River delta to the Niger River delta. This coast has, however, been significantly impacted over the last 50 years by the construction of three deepwater ports in Lomé (Togo), Cotonou (Benin) and Lagos (Nigeria) that have intercepted sand supply, as well as by a major dam on the Volta River, resulting in destabilization of the former single drift cell on this coast. The ensuing multi-cellular structure is characterised by long sectors of rampant coastal erosion that threatens parts of these cities, coastal villages and infrastructure.
Robin, N., Certain, R., Bouchette, F., Anthony, E.J., Meulé, S., and Aleman, N., 2014. Wave-driven circulation over a double nearshore bar system during storm conditions. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 084–089, ISSN 0749-0208.
Current profiles and waves were recorded from a multi-instrumented transect over a double nearshore bar system in the Gulf of Lions, NW Mediterranean Sea (France) during storm conditions with shoreface significant wave heights of up to 3.2 m. The results constitute a preliminary analysis aimed at constraining the 3D nearshore circulation in a microtidal system. Significant time changes in the vertical distribution of nearshore velocities were observed, forced by the wind/wave conditions. Such vertical changes have been highlighted by theoretical velocity profiles in the literature, but our study demonstrates much larger variability than has hitherto been shown. Another result obtained was that the hydrodynamic pattern observed in the inner trough was distinct from that observed along the seaward flank of the inner bar. For a well-defined threshold in wave height, velocities in the trough increased abruptly and earlier, and remained strong over a longer time than those on the seaward flank. The trough thus behaves essentially as a drain for water piled against the shore. This behavior is altered by the width of the surf zone (and not only by the significant wave height), which modulates the mean current velocity. These results are a useful preliminary step in improving numerical modeling of the complex surf-zone circulation over bar-trough systems.
Anderson, A., Vilumaa, K., Tõnisson, H., Kont, A., Ratas, U., Suuroja, S., 2014. Geomorphology of coastal formations on present and ancient sandy coasts. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 090–095, ISSN 0749-0208.
Many coastal sites are experiencing land uplift, so coastal formations can be found many kilometres inland from the present day shoreline. However, due to the relatively rapid, site specific and complicated development, their evolution is not very thoroughly studied yet. In this study, we analyse sediments and subsurface stratigraphy to explain the evolution and geomorphology of coastal formations (from present to ancient coastlines) located in sediment supply-limited areas. Several study sites were chosen on Tahkuna Peninsula, Hiiumaa Island in Estonia, where the rate of land uplift is 2.8 mm yr−1. Due to deficiency of sediment, dunes and old beach ridges that developed during the last 3,500 years are low (dunes up to 6–7 m, the studied ridges mostly less than 2 m). The coastal formations studied are located at different distances (up to 1 km) from the shoreline and at different altitudes (up to 13.2 m above sea level).
In the current research, granulometric analysis was used for studying the coastal formations; grain size was determined by dry sieving of sediments. Additional studies were carried out with ground-penetrating radar (SIR-3000) to compare the present and former coastlines and to explain geomorphic differences. Drilling was also used and special pits were dug for the examination of mineral deposits. The preliminary results show that the sands on the present coastline are similar to those of former shorelines, which may be caused by the wind regime, time scale for coastal formation development, and underlying sediments.
Balouin, Y., Belon, R., 2014. Evolution of Corsican pocket beaches. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 096–101, ISSN 0749-0208.
Pocket beaches are small beaches that are formed between headlands and within coves along rocky shorelines. They can be composed of a mix of boulders, pebbles, sand and mud and therefore have the attributes of a combination of shoreline types. Their evolution depends on wave forcing and morphological characteristics, and the most commonly observed dynamic is that of beach rotation due to prevailing wave direction. In this study, 44 pocket beaches off Corsica Island, in the Mediterranean were studied. The absence of significant tides and the generally weak coastal currents restrict significant beach morphology changes to the most important storm events though the variability of coastal evolution suggests that other factors played a role. To assess these evolution parameters, the morphological characteristics of the beaches as well as the historical evolution of the shoreline were studied. This analysis, based on aerial photos and DGPS surveys, allowed for the behavior of beaches over historical (1948–2012) period to be assessed. Over this period, 15 beaches are considered to be in erosion, 16 are stable and the others show shoreline progression. The historic analysis, through several increments of time, shows that beaches have been in perpetual movement. Moreover, some periods are particularly erosive (i.e., 1996 to 2002) for a number of beaches. Several parameters must be considered to explain the beach behavior changes such as: beach orientation, closure, geology, hydro-climatic regime, grain size and length. The wave backward modeling ANEMOC was used to analyze wave characteristics and the occurrence and direction of the most important storm events. The entire dataset was used to obtain a conceptual model describing the most important factors involved in the contrasting coastal evolutions observed, i.e., symmetric or asymmetric beach rotation, homogeneous retreat or progradation and rapid shoreline movements due to the presence of beach-cast Posidonia Oceanica seagrass litter.
This article is only available to subscribers. It is not available for individual sale.
Access to the requested content is limited to institutions that have
purchased or subscribe to this BioOne eBook Collection. You are receiving
this notice because your organization may not have this eBook access.*
*Shibboleth/Open Athens users-please
sign in
to access your institution's subscriptions.
Additional information about institution subscriptions can be foundhere