Coastal Sector Research Articles

Assessment of stability of an exposed microtidal beach, Western Tasmania

Beach erosion is an increasing threat to the natural resources of many countries, and is expected to increase with rising sea-level. West Tasmania has extensive fetch from the circum-polar Antarctic Ocean, also located in the “Roaring Forties” latitudes. Beaches of this coastline previously studied have shown major erosion, attributed to recent relative sea-level rise as they are largely secluded from human impacts. This study assessed Four Mile Beach, located in the central section of the west coast using methods of spatial analysis 1952–2011, beach profile survey and sediment analysis. Results showed only minor erosion of the vegetation line to the north, and stability and progradation in the central and southern extents of the beach. Blowouts showed more major changes, with three large blowouts towards the south becoming parabolic dunes, and one in the north re-vegetating. Dune sediment was mostly rounded fine sand indicative of active aeolian processes, while seaward edge sediment was sub-angular with a 15–20% of carbonate content on most transects, indicative of a sediment supply from offshore. Ongoing coastal stability of this pristine coastline would be facilitated by continued monitoring, management of any potential human impacts, and control of any potential invasive species that may affect sediment budgets.

Ember risk modelling for improved wildfire risk management in the peri-urban fringes

Although embers are a leading cause of house loss and damage from wildfire, risk reduction activities such as vegetation management and planning requirements do not adequately account for the risk of embers. To help address this, a model of the potential ember risk is presented. It takes into account local vegetation and background wind conditions for both long-range and short-range ember dispersal. This model is developed to provide indications of the importance of embers to the household-level wildfire risk in communities at the wildland-urban interface. The model provides information for householders to improve understanding of the nature of ember risk within the community, and to assist planning in order to respond to that risk. A case study of the 2015 Warringine Park (Coastal Section) bushfire in Australia is presented, which demonstrates how the model could be used to assist with community planning. The utility of this outcome for community and household level wildfire planning and preparation is discussed.

Shoreline Changes and Coastal Erosion: The Case Study of the Coast of Togo (Bight of Benin, West Africa Margin)

The coastal strip between the Volta River delta and the westernmost portion of Benin (West Africa Margin of Atlantic Basin) is highly populated (e.g., Lomé) due to migrations from inland areas. The coastal zone has proved to be very vulnerable because of the potential development of sometimes catastrophic events related to different and interacting causes, resulting in negative effects on natural ecosystems and socio-economic conditions. The main problem is the marked erosion of large coastal sectors with maximum retreat rates of the order of 5 m/year. The continuous loss of territory leads to a progressive impoverishment of activities and human resources and to the increase of geological risk factors. The coastal erosion is induced both by natural and anthropic causes and can be controlled only by means of prevention programs, detailed scientific studies and targeted technical interventions. The main erosional processes observed in the study area are triggered by the presence of the Lomé port and other human activities on the coastal strip, including the water extraction from the subsoil, which induces subsidence and the use of sediments as inert material. These elements, together with the reduction of the solid supply from Volta River (caused by the realization of the Akosombo dam) are among the main factors that control the medium and long-term evolution of the area. Also relative sea level changes, which take into account also tectonic and/or isostatic components, can contribute to the process. In order to have a real understanding of the coastal dynamics and evolution, it would be necessary to develop a scientific structure through the collaboration of all countries of the Bight of Benin affected by coastal erosion. The aim should be primarily to collect the interdisciplinary quantitative data necessary to develop a scientific knowledge background of the Bight of Benin coastal/ocean system. In conclusion, some proposals are presented to reduce the vulnerability of the coastal area as for example to plan surveys for the realization of appropriate coastal protection works, such as walls, revetments, groins, etc. A possible expansion of the port of Lomè is also considered. Proposals comprise the constitution of a Supranational Scientific Committee as a coordinating structure on erosion for both the study of phenomena and planning interventions.

Barrier Islands Resilience to Extreme Events: Do Earthquake and Tsunami Play a Role?

Barrier islands are indicators of coastal resilience. Previous studies have proven that barrier islands are surprisingly resilient to extreme storm events. At present, little is known about barrier systems’ resilience to seismic events triggering tsunamis, co-seismic subsidence, and liquefaction. The objective of this study is, therefore, to investigate the morphological resilience of the barrier islands in responding to those secondary effects of seismic activity of the Sumatra–Andaman subduction zone and the Great Sumatran Fault system. Spatial analysis in Geographical Information Systems (GIS) was utilized to detect shoreline changes from the multi-source datasets of centennial time scale, including old topographic maps and satellite images from 1898 until 2017. Additionally, the earthquake and tsunami records and established conceptual models of storm effects to barrier systems, are corroborated to support possible forcing factors analysis. Two selected coastal sections possess different geomorphic settings are investigated: (1) Lambadeuk, the coast overlying the Sumatran Fault system, (2) Kuala Gigieng, located in between two segments of the Sumatran Fault System. Seven consecutive pairs of comparable old topographic maps and satellite images reveal remarkable morphological changes in the form of breaching, landward migrating, sinking, and complete disappearing in different periods of observation. While semi-protected embayed Lambadeuk is not resilient to repeated co-seismic land subsidence, the wave-dominated Kuala Gigieng coast is not resilient to the combination of tsunami and liquefaction events. The mega-tsunami triggered by the 2004 earthquake led to irreversible changes in the barrier islands on both coasts.

User Needs Analysis for the Definition of Operational Coastal Services

According to the global growth of the “Blue economy”, coastal zones are under pressure from both land and marine side economic activities. The fragmentation of sectorial interests and legislation along the coasts has led to the need for bridging knowledge (data/information and methods/tools) and governance (decision-makers at every level) in order to ensure sustainable economic development and social and ecosystem resilience. This poses the need for an interaction process that associates user needs to the European and national legislative framework to create a policy-oriented demand of Copernicus Earth Observation services in coastal areas. Such goals need a strong and effective system to monitor compliance and to assess the progress of the legislation. This study aims at identifying potential gaps in the current Copernicus product offer for the monitoring of the coastal sector through the elicitation of stakeholder requirements. The methodology is applied to the Italian landscape of users, but it is scalable at European level. The results provide a clear overview of the coastal user requirements, highlighting the common need of integrated information for the management, and represents the basis for defining the coastal services.

Contribuições de Paulo Freire na Educação do Campo: formação de professores/as e o ensino de Ciências

This work presents a reflection on the theoretical and methodological thinking of the Brazilian educator Paulo Freire in the field of the Countryside Education and his contributions to the process of training teachers of Natural Sciences. With this objective, the Pre-service teacher education courses of the Countryside Education at the Federal University of Paraná - Coastal Sector was taken as a reference, from which the historical, philosophical, social and practical principles and influences that led to the implantation of courses of this nature at national public universities are presented. Methodologically, it is a theoretical study, but it also has empirical evidence of educational practices already carried out. Among the final reflections, the importance of Freire’s pedagogy stands out as a counter-hegemonic and guiding pedagogy for the education of the people from the rural areas, waters and forests. Keywords: Freirean thinking. Training of countryside teachers.

Историко-географическая эволюция Бессарабии по сведениям старинных карт

Problems of research of the territorial development of the old-developed regions are due to the duration and extraordinary saturation of historical processes that flowed and continue in them. The study of changes in the territories of states and various entities is important not only for understanding the past: local and regional conflicts whose roots often go deep into centuries, remain for a long time and continue these days, territorial claims are relevant now. This is especially evident on the example of such regions of oldest development, as the Black Sea region. Historic-cartographical studies, systematization of previously known and newly identified sources, the analysis of old geographical maps and plans allow us to form a holistic picture of the evolution of space, its territorial structure, as well as the functional role of one or another place in the past and present. In the article on the example of Bessarabia—the historic-geographical region of the North-Western Black Sea coast—the most important cartographic works presented, being key for certain stages of its historic-geographical evolution and development of cartography as a whole: the Antiquity and the Middle Ages (when the first geographical maps appeared), the 15th–18th centuries (when the toponym under study was first applied into maps, and detailed topographic maps began to be created) and the 19th–20th centuries (when political events again changed the semantics of the toponym Bessarabia). It is shown how geographical representations of the region transformed during different historical periods. The content of the toponym denoting region is considered, at different times related to different sections of the Black Sea coast and included various territories, as well as its use today as a political tool reflecting actual territorial claims.

Modeling Integrated Coastal Flood Hazard in Hurricane Season

The manuscript proposed a procedure designed to determine the hazard of total coastal flooding during the impact of hurricanes, which uses in its formulation the combination of river flooding and that caused by marine upwelling, which is multiplied by a density factor of the water that finds an explanation for the effect is shielding and rising of the water level when the currents of both floods collide in the coastal zone. The application of the procedure experimentally in the coastal sector Sevilla, of the municipality Guama province Santiago de Cuba, resulting in the confirmation of areas previously modeled and estimated coastal flooding in the wake of extreme weather events in the study area; in addition to other new areas that confirm the actual visual and instrumental observations not included in previous studies.

A diachronic study of the Mediterranean coastline: A geometric approach

Coastal areas represent one of the country's most important environmental and economic resources. They are naturally dynamic, with changes that can occur on a human time scale and that need to be quantified for the proper management of shorelines and, in particular, the beaches on which the local economy is largely based. This work focuses on the diachronic study of the coastline of the Mediterranean coast, particularly the coastal fringe at the mouth of the Wadi Aliane. In order to assess and remedy the risks of erosion and accretion of the coastline, the methodology followed consists of the application of automatic analytical techniques using multi-temporal photo-interpretation, a Geographic Information System (GIS) and a Digital Shoreline Analysis System (DSAS). The rate of change will be calculated from the multi-date maps, (1981- 1997 and 2016) using the End Point Rate (EPR) index. Comparison of the results of the interpretation of aerial photos and satellite images of the Oued Aliane coastline used (1981, 1997, and 2016) provided information that allowed us to understand the evolutionary behaviour of the wet sand/dry sand line over 36 years. This numerical analysis of the 1981 -1997 and 2016 coastlines in the coastal sector of Oued Aliane, shows us that zones A, C and D are mainly affected by erosion, while the mouth part is affected by accretion because it is considered a delta and therefore a sedimentation area.

Observed Changes of a Mega Feeder Nourishment in a Coastal Cell: Five Years of Sand Engine Morphodynamics

Recently, mega feeder nourishments have been proposed as a new strategy to nourish sediment-starving beaches. This strategy involves the placement of a large, concentrated sediment volume at a single location along the coast. Wind, waves and currents act as the natural agents to spread the sediment alongshore over the course of years to decades. This article presents the morphological development of the first full-scale implementation of this strategy, examining the 20 × 106 m3“Sand Engine” feeder nourishment and its impact on adjacent coastal sections. The analysis is based on 37 high-resolution topographical surveys, executed in a 17 km coastal cell. These unique data describe the alongshore spreading in the first five years and the response at different elevations of the coastal profile. The analysis shows rapid transformation of the nourishment’s planform shape, changing rapidly into a smooth (Gaussian-like) shape which is gradually extending alongshore over time. Within five years, sediment has been distributed to a 5.8 km stretch of coast from the initial 2.2 km peninsula footprint. Changes in cross-shore and alongshore extent varied strongly over depth, with the strongest morphological response at the mean sea level (MSL) isobath and limited morphodynamic activity at deeper water, below −8 m MSL. This depth-dependent response has resulted in decreasing subtidal slopes in eroding areas, accretive areas contrastingly show a slope increment. These results yield important insights in nourished sediment mobility at different depths near the coast and distribution over a larger coastal cell. However, this single-design assessment cannot address the wide range of mega nourishment design parameters essential for morphological development of its coastal cell. This work suggests limiting cross-shore extent, since it is uncertain whether nourished sediment at deeper water will become active in the coastal system. A continuation of the current monitoring and future research might shed more light on this.

Victoria Land, Antarctica: An Improved Geodynamic Interpretation Based on the Strain Rate Field of the Current Crustal Motion and Moho Depth Model

In Antarctica, the severe climatic conditions and the thick ice sheet that covers the largest and most internal part of the continent make it particularly difficult to systematically carry out geophysical and geodetic observations on a continental scale. It prevents the comprehensive understanding of both the onshore and offshore geology as well as the relationship between the inner part of East Antarctica (EA) and the coastal sector of Victoria Land (VL). With the aim to reduce this gap, in this paper multiple geophysical dataset collected since the 1980s in Antarctica by Programma Nazionale di Ricerche in Antartide (PNRA) were integrated with geodetic observations. In particular, the analyzed data includes: (i) Geodetic time series from Trans Antarctic Mountains DEFormation (TAMDEF), and Victoria Land Network for DEFormation control (VLNDEF) GNSS stations installed in Victoria Land; (ii) the integration of on-shore (ground points data and airborne) gravity measurements in Victoria Land and marine gravity surveys performed in the Ross Sea and the narrow strip of Southern Ocean facing the coasts of northern Victoria Land. Gravity data modelling has improved the knowledge of the Moho depth of VL and surrounding the offshore areas. By the integration of geodetic and gravitational (or gravity) potential results it was possible to better constrain/identify four geodynamic blocks characterized by homogeneous geophysical signature: the Southern Ocean to the N, the Ross Sea to the E, the Wilkes Basin to the W, and VL in between. The last block is characterized by a small but significant clockwise rotation relative to East Antarctica. The presence of a N-S to NNW-SSE 1-km step in the Moho in correspondence of the Rennick Geodynamic Belt confirms the existence of this crustal scale discontinuity, possibly representing the tectonic boundary between East Antarctica and the northern part of VL block, as previously proposed by some geological studies.

Sex-related and spatial variation in trace elements in feathers of the Kentish plover (Charadrius alexandrinus) from different coastal areas of the Iberian Peninsula

This study investigated the sex-related and spatial variation in trace elements concentrations in feathers of the Kentish plover (Charadrius alexandrinus) inhabiting different coastal locations in the Iberian Peninsula. Feathers were sampled in a total of 50 breeding birds from 7 different locations: 3 on the Mediterranean coast (n=18), 1 on the Atlantic coast of Andalusia (n=9) and 3 on the NW Atlantic coast (n=23). The feathers were analyzed to determine the concentrations of Al, Cr, Mn, Cu, Zn, As, Se, Cd, Hg and Pb. All of the trace elements were present at detectable concentrations, and the mean concentrations of Al, Zn and Cu were highest of those considered. The coastal section had a significant effect on 5 elements (Mn, Cu, As, Cd and Pb). The mean concentrations of almost all of the trace elements were highest in the birds from Andalusia, intermediate in the birds from the Mediterranean area and, in general, lowest in the birds from the NW Atlantic coast. Females showed significant higher Mn concentrations and high levels of exogenous elements (Al and As) in contrast with males. Less preening activity during the day of female birds, when they are occupied in incubating eggs, could favour higher concentrations of exogenous trace elements. The high levels of several trace elements observed in the samples from Mediterranean and Atlantic coast of Andalusia may pose a serious threat to these populations.

Effect of artificial seagrass on hydrodynamic thresholds for the early establishment of Zostera marina

Seagrass meadows have disappeared on many coastal sections due to anthropogenic disturbances, diseases, and/or eutrophication. To facilitate informed seagrass restoration, we i) quantified the hydrodynamic dislodgement thresholds for newly transplanted Z. marina shoots, and ii) tested the effect of artificial seagrass (ASG) as a hydrodynamic protection measure. Experiments were carried out by planting Z. marina rhizomes with living shoots into a sediment bed and exposing them to a range of wave and current conditions in a flume. The use of ASG significantly reduced wave height, as well as current velocity. The applied waves led to the development of ripples whereas currents led to erosion of the sediment bed. The number of shoots that were uprooted and dislodged increased with increasing bed shear stress and erosion. By reducing bed shear stress, the ASG raised the input current velocity threshold, which the transplanted shoots were able to withstand. The present study offers insight into the effect of artificial seagrass (ASG) on wave and current attenuation, as well as sediment erosion and shoot dislodgement. Our results help to inform the setting of hydrodynamic thresholds for the early establishment of Z. marina and to define the improvement of hydrodynamic conditions by ASG.

Launching a Blue Economy: crucial first steps in designing a contextually sensitive and coherent approach

ABSTRACT The Blue Economy is an emerging framework through which sustainable development is being pursued within the oceans. To date there is limited guidance into how a Blue Economy should be enacted. We propose four initial steps in the development of Blue Economy policies and plans. Firstly, we argue for early deliberation over what is meant by the Blue Economy within the relevant context. Secondly, consideration of the sectors that make up a Blue Economy should be articulated. Thirdly, we argue that Blue Economy plans should aim to be coherent within the existing policy framework. Therefore, an assessment is required of the existing policy settings for the relevant marine and coastal sectors, and the degree to which they are already coherent, or ‘mutually consistent’ with each other. Finally, a contextually sensitive and coherent Blue Economy policy can be designed which plugs policy gaps and adds value to the existing situation. We test the application of these four steps in two different case study areas, a region of Australia and Timor Leste. Despite substantial differences in context, the process identified ways in which Blue Economy policies could add value to existing governance arrangements in both settings.

Geomorphological Difference and Genesis of Typical Sandy Coasts in the Northern and Southern Shandong Peninsula

Yue, B.; Liu, S.; Yan, Z.; Liao, J., and Gao, M., 2021. Geomorphological difference and genesis of typical sandy coasts in the northern and southern Shandong Peninsula. Journal of Coastal Research, 37(2), 380–388. Coconut Creek (Florida), ISSN 0749-0208.Two landform monitoring sections of sandy coasts in the southern and northern Shandong Peninsula are chosen as the research objects. Empirical orthogonal functions were used to extract the spatial characteristics function and time characteristics function of the first four modes from the monitoring data in summer and winter from December 2012 to December 2015. Characteristics of spatial changing and beach flat variation of the two sandy coasts were analyzed. Differences in geomorphic features and sedimentary characteristics between the southern and northern coasts have been compared. The difference and impact factors of the dynamic environment in the northern and southern Shandong Peninsula were discussed in this paper. The results show that the first characteristic function is the main model of showing beach section change. On the southern coast, the beach section presents a gradually enhancing trend characteristic from a beach berm to a broken belt. The northern coast shows the main fluctuation characteristic from the high tidal zone to an upper limit of the upper bound, which is related to waves and tides. Moreover, the second and third characteristic functions are controlled by seasonal periodic changes in stormy waves. The fourth characteristic function is speculated to be related to accidental factors.

Dominant Regulatory Factor of Shoreline Erosion Process: The Case of Western Coastal Sector in Sri Lanka

Dominant Regulatory Factor of Shoreline Erosion Process: The Case of Western Coastal Sector in Sri Lanka

Bedload Sediment Rate Prediction for the Sand Transport Along Coastal Waters in Ocean Management Strategy

Interactions among different landforms and varied complicated physical processes cause sediment transport in coastal regions being the interest of ocean management planning studies. In coastal zones, the derivation of the bedload sediment transport rate and the flow velocity distribution is done by entropy theory which assumes the modified spatiotemporal disorder power index (MSTDPI) and the time-averaged flow velocity (as a random variable). Studying the deposition trend of bedload sediment transport rate for the sand particle (BLSTRS) and estimating the coastal erosion rate as a case study, the Makran coast is selected. To analyze the spatiotemporal patterns, the disorder power index (entropy-power) method is applied in this study where the monthly data of six Makran coastal sections from January 1970 to December 2015 are used. The studied data are mainly focused on the correlation of the flow rate of the sediment from the Makran River, and the spatiotemporal patterns of BLSTRS. Despite their meaningful spatiotemporal variability, it is not very easy to explain how the abovementioned variables perform together; the entropy-power index allows a better understanding of the combined performance of such parameters as the flow velocity and sediment transport by showing clearer signals for the assessment of coastal engineering issues at very large (coastal) scales.

Dynamical descriptors of physical vulnerability to sea-level rise in sheltered coastal systems: A methodological framework

Many studies about the susceptibility of coastal systems to flood hazard have been carried out using similar methodological approaches, based on the spatial integration of structural and dynamical variables. However, although the general framework fits well to most exposed coastal sectors, few examples can be found in the literature regarding the proposal of dynamical descriptors (variables of process) particularly relevant to the analysis of the physical vulnerability of sheltered coastal systems, such as lagoons. The aim of this study was to propose a methodology to assess the physical vulnerability to sea-level rise due to climate change which was tested in the Conceição Lagoon, located in Santa Catarina (Brazil), based on dynamic descriptors obtained from numerical modeling. After implementing a numerical model calibrated to satisfactorily reproduce the hydrodynamic characteristics of the studied system, we simulated different sea-level rise scenarios proposed by the Intergovernmental Panel on Climate Change (IPCC), using optimistic and pessimistic scenarios for the years 2050 and 2100. Results were classified following the often-adopted scheme of very low to very high vulnerability. The maximum variations in the lagoon level calculated by the model showed the importance of winds and tides (both astronomical and meteorological) as the main triggering processes of level oscillation. The final physical vulnerability spatial distribution, obtained by the integration of maximum lagoon level variations associated with future projections, allowed the recognition of the sectors within the lagoon system which are more prone to suffering impacts. Most of the system was considered to have an intermediate vulnerability to sea-level rise. However, sectors with high vulnerability were also identified, mostly located at the northern and southern shores of the lagoon (due to wind influence), as well as along its inlet margins (due to ocean dynamics). The proposed framework based on the variations of the water level can be widely adopted as a descriptor that synthesizes the main dynamic processes responsible for the physical vulnerability of sheltered systems, fitting to lagoons and bays with different physiographic characteristics. The determination of the spatial distribution of areas with different degrees of susceptibility can be a valuable tool for coastal planning and management actions to be performed in sheltered systems, which has been overlooked comparing to those applied in open coasts.

Late Quaternary landscape evolution of the buried incised valley of Concordia Sagittaria (Tagliamento River, NE Italy): A reconstruction of incision and transgression

While recent landscape changes can be usually easily read through accessible morphological features, relatively ancient processes can be difficult to detect as the associated morphologies and deposits are often buried below younger sediments. With the aim of understanding the evolution of the distal Venetian-Friulian Plain (NE Italy) after the Last Glacial Maximum (LGM), this work presents the analysis performed on a dataset of ca. 2300 mechanical and hand-made cores, which allowed a detailed reconstruction of the formation and evolution of an incised valley, now almost completely filled and with little to absent morphologic expression. Such valley, up to 1.2 km wide, with a depth of 20 m below the LGM alluvial plain and traced for a length of 25 km, is the result of the complex interplay between minor spring-fed rivers and the Tagliamento River. The detailed characterization of the infilling allowed to identify two main phases in the valley evolution. The first one is related to the activity of the paleo Tagliamento River and led to the deposition of a 10 m thick gravelly unit (ca. 19–9.5 ka cal BP). The second phase, which followed a disconnection of the Tagliamento, is linked to the Holocene marine transgression and led to the formation of a lagoon environment within the valley and to the deposition of a ca. 15 m thick unit of lagoon muds (ca. 8 ka cal BP - historic time). This latter unit lays on top of gyttja deposits, indicating for the first time in this area the presence of widespread lacustrine environments in the Early Holocene. This work presents an in-depth analysis on the evolution of a distal plain incised valley, from its formation to its final filling, providing at the same time the means to describe the development of the entire alluvial plain landscape, spanning from the end of the LGM to the middle Holocene. We present new data on the paleoenvironmental and morphologic evolution of the Venetian-Friulian Plain area as a consequence of the interplay between autogenic forces and sea-level rise. Our study allowed to understand the importance of both Alpine rivers and groundwater-fed streams in the formation of large incised valleys in the coastal sector of the whole Venetian-Friulian Plain. Finally, as during the transgressive phase the upstream sediment input in the valley was almost absent, this study provides insights into facies and architecture of a rare example of downstream-controlled filling of an incised valley.

An approach to coastline evolution as a tool for coastal management: case study of La Pedrera—Cabo Polonio Bay (Rocha, Uruguay)

A study of the position of the coastline was performed from the recent past (50 years) to Holocene ages (about 5000 years ago) in La Pedrera–Cabo Polonio coastal sector, in the southeast of Uruguay. Some persistent geoforms, such as marshes, located at very low elevations present lowest displacement of the recent coastline. Other recent landscapes, such as coastal gullies, developed on Late Pleistocene sediments are associated with a progradational coast in the short term. The geomorphological cartography was a useful tool for coastal management in the scenario of 10 cm sea-level rise per century and a coastal retreat of about 1 m per year. The analysis of coastline evolution provides information to assess the best measures to prevent coastal erosion and identify vulnerable areas. The presence of an escarpment (paleo coastline) located around + 10 to + 5 m above the current sea level appears to be the most appropriate criterion of minimum setback distances from current coastlines for constructions.