scholarly journals Sand Trapping Fences as a Nature-Based Solution for Coastal Protection: An International Review with a Focus on Installations in Germany

Environments ◽  
2021 ◽  
Vol 8 (12) ◽  
pp. 135
Author(s):  
Christiane Eichmanns ◽  
Simone Lechthaler ◽  
Wiebke Zander ◽  
Mariana Vélez Pérez ◽  
Holger Blum ◽  
...  

Sand trapping fences are a widely used nature-based solution to initiate dune toe growth along sandy shorelines for coastal protection. At present, the construction of sand trapping fences is based on empirical knowledge, since only a few scientific studies investigating their efficiency exist. However, the restoration and maintenance of beach-dune systems along the coast requires knowledge of the interaction between the beach-dune system and the sand trapping fences to provide guidance for coastal managers on how and where to install the fences. First, this review gives an overview of the typical aerodynamic and morphodynamic conditions around a single porous fence and the influence of various fence height and porosity values to understand the physical processes during dune establishment. Second, different approaches for evaluating the efficiency of sand trapping fences to trap sediment are described. This review then highlights significant differences between sand trapping fence configurations, nationally as well as internationally, regarding the arrangement, the materials used, and the height and porosity. In summary, it is crucial to enable an intensive exchange among the respective coastal authorities in order to create uniform or transferable guidelines taking local conditions into account, and thus work collaboratively on the idea of sand trapping fences as a nature-based solution in coastal areas worldwide.

2017 ◽  
Author(s):  
Gemma L. Franklin ◽  
Alec Torres-Freyermuth ◽  
Gabriela Medellín ◽  
María Eugenia Allende-Arandia ◽  
Bernabé Gómez ◽  
...  

Abstract. Reefs and sand dunes are critical morphological features providing natural coastal protection. Reefs dissipate around 90 % of the incident wave energy through wave breaking, whereas sand dunes provide the final natural barrier against coastal flooding. The storm impact on coastal areas with these features depends on the relative elevation of the extreme water levels with respect to the sand dune morphology. However, despite the importance of the barrier reefs and dunes in coastal protection, poor management practices have degraded these ecosystems, increasing their vulnerability to coastal flooding. The present study aims to investigate the role of the reef-dune system in coastal protection under current climatic conditions at Puerto Morelos, located in the Mexican Caribbean Sea. Firstly, a nonlinear non-hydrostatic numerical model (SWASH) is validated with experimental data from a physical model of a fringing reef. The numerical model predicts both energy transformation and runup statistics as compared with experimental results for two different reef crest geometries conducted in a physical model. Thus, the numerical model is further used to investigate the role of the reef-dune degradation in coastal vulnerability. Wave hindcast information, tidal level, and a measured beach profile of the reef-dune system in Puerto Morelos are employed to predict extreme runup and estimate the storm impact scale for different scenarios. The numerical results show that ecosystem degradation has important implications for coastal protection against storms with return periods of less than 10 years. This highlights the importance of conservation of the system as a mitigation measure to decrease coastal vulnerability and infrastructure losses in coastal areas in the short to medium term.


2021 ◽  
Vol 10 (1) ◽  
pp. 14
Author(s):  
Giuseppe Barbaro ◽  
Giandomenico Foti ◽  
Giuseppina Chiara Barillà ◽  
Ferdinando Frega

The dune systems are very important from an environmental, landscape, and coastal defense point of view within coastal areas. Currently, dune systems are significantly reduced compared to a few decades ago and, in Europe alone, dune systems have decreased by 70%. During the same period, intense beach erosion processes have often been observed, and, currently, 30% of the world’s coasts are eroding. These processes have various causes, both natural and anthropogenic, and the knowledge of the causes of the erosive processes are very important for an effective planning and management of coastal areas and to correctly plan any interventions on dunes and beaches. The paper, through a case study, analyzes the beach and dune erosive processes, their causes, and the possible interventions. The case study concerns the archaeological site of Kaulon, located on a dune in the Ionian coast of Calabria (Italy). The beach near the site was affected by erosive processes and during the winter of 2013–2014, the site was damaged by two sea storms. To identify the causes of these processes, three erosive factors were analyzed. These factors are anthropogenic pressure, wave climate and sea storms, and river transport. The effects produced by these factors were assessed in terms of shoreline changes and of damage to the beach–dune system, also evaluating the effectiveness of the defense interventions. The main causes of the erosive processes were identified through the cross analysis of erosive factors and their effects. This analysis highlighted that in the second half of the last century the erosive processes are mainly correlated to anthropogenic pressure while, recently, natural factors prevail, especially sea storms. Regarding the interventions, the effects produced by two interventions carried out during the winter of 2013–2014, one built in urgency between the first and second sea storm and the other built a few years after the second sea storm were analyzed. This analysis highlighted that the latter intervention was more effective in defending the site.


2019 ◽  
Vol 21 (2) ◽  
pp. 364-380
Author(s):  
Antônio Emanuel dos' Santos Silva ◽  
Matheus Silveira Pinheiro ◽  
Davis Pereira de Paula

Ambientalmente as dunas frontais constituem estruturas verdes de proteção costeira contra o avanço do mar, em muitos casos, são responsáveis pela manutenção do equilíbrio sedimentar do sistema praia-duna, impedindo que processos como a erosão costeira e a inundação marinha se tornem danosos a sociedade civil e ao patrimônio construído. O objetivo deste estudo foi monitorar as variações morfológicas e sedimentares do sistema praia-duna entre os anos de 2016 e 2018, no trecho extremo oeste da Praia do Icaraí, através da determinação das taxas granulométricas, volumétricas e morfológicas do sistema praia-duna na Praia do Icaraí. Os procedimentos metodológicos foram divididos em três etapas principais: levantamento bibliográfico, geocartográfico e experimentos de campo. Considerou-se que as forçantes oceanográficas foram as principais responsáveis pela erosão e solapamento das dunas frontais presentes na área de estudo. Em linhas gerais, os resultados deste trabalho significam um importante instrumento de análise dos impactos das condicionantes oceanográficas e antrópicas sobre uma praia que sofre de erosão costeira acentuada. O estudo em um trecho mais preservado dessa praia indicou de forma direta os impactos sofridos em um litoral que vem passando por transformações contínuas em suas praias, como é o caso do litoral de Caucaia.Palavras-chave: Morfodinâmica; Sistema Praial; Dunas Frontais. ABSTRACTEnvironmentally the frontal dunes constitute green structures of coastal protection against the advance of the sea, in many cases, they are responsible for the maintenance of the sedimentary balance of the beach-dune system, preventing that processes such as coastal erosion and marine flooding become harmful to civil society and built heritage. The objective of this study was to monitor the morphological and sedimentary variations of the beach-dune system between the years 2016 and 2018, in the extreme west section of Icaraí Beach, by determining the granulometric, volumetric and morphological rates of the beach-dune system in Praia of Icaraí. The methodological procedures were divided into three main stages: bibliographic survey, geocartographic and field experiments. It was considered that the oceanographic forcings were the main responsible for the erosion and overlap of the frontal dunes present in the study area. In general terms, the results of this work represent an important instrument for analyzing the impacts of oceanographic and anthropogenic conditions on a beach that suffers from marked coastal erosion. The study in a more preserved stretch of this beach indicated in a direct way the impacts suffered on a coast that has undergone continuous transformations in its beaches, as is the case of the coast of Caucaia.Keywords: Morphodynamics; Praial System; Fore Dunes. RESUMENAmbientalmente, las dunas frontales son estructuras verdes de protección costera contra el avance del mar. En muchos casos, son responsables de mantener el equilibrio sedimentario del sistema de dunas de playa, evitando que procesos como la erosión costera y las inundaciones marinas dañen a la sociedad civil. y el patrimonio construido. El objetivo de este estudio fue monitorear las variaciones morfológicas y sedimentarias del sistema de dunas de playa entre 2016 y 2018, en el extremo occidental de Praia do Icaraí, determinando el tamaño de partícula, las tasas volumétricas y morfológicas del sistema de dunas de playa en Praia de Icaraí Los procedimientos metodológicos se dividieron en tres etapas principales: estudio bibliográfico, geocartográfico y experimentos de campo. El forzamiento oceanográfico se consideró el principal responsable de la erosión y el debilitamiento de las dunas frontales presentes en el área de estudio. En general, los resultados de este trabajo representan un instrumento importante para analizar los impactos de las condiciones oceanográficas y antropogénicas en una playa que sufre una severa erosión costera. El estudio en un tramo más preservado de esta playa indicó directamente los impactos sufridos en una costa que ha sufrido cambios continuos en sus playas, como es el caso de la costa de Caucaia.Palabras claves: Morfodinámica; Sistema de playa; Dunas frontales.


Shore & Beach ◽  
2021 ◽  
pp. 17-21
Author(s):  
A.T. Williams

Between the years 1200 and 1600, vast quantities of sand were brought inshore from offshore bars as a result of centuries of ferocious storms, to form a series of dune systems along the South Wales coastline. Today, as a result of many housing, leisure, and industrial developments only a few remnants exist. On one such remnant at Porthcawl, Wales, UK, became a caravan site in the 1930s, which was abandoned in 1993 for political reasons. Within 27 years a minimum of 120,000 m3 of sand was transported from the adjacent beach and formed dunes >4 m in height along a 400- m frontal edge that extended some 130 m inland, approximately a third of the site. Typical vegetation found along the frontal part of the system are Ammophila arenaria (marram), Agropyron junceiforme (sand couch grass) and Euphorbia maritimum (spurge). To the rear of the system, vegetation included Agrostis tenuis and stolonifera, (bent and creeping bent grass), Cirsium avense (creeping thistle), and Caluna vulgaris (heather). A 4-m-high and c. 3000m2 area of a vigorous stand of Hippophae rhamnoides (sea buckthorn) has also formed. The rapidity of dune formation and vegetation colonization is staggering.


2018 ◽  
Vol 18 (4) ◽  
pp. 1247-1260 ◽  
Author(s):  
Gemma L. Franklin ◽  
Alec Torres-Freyermuth ◽  
Gabriela Medellin ◽  
María Eugenia Allende-Arandia ◽  
Christian M. Appendini

Abstract. Reefs and sand dunes are critical morphological features providing natural coastal protection. Reefs dissipate around 90 % of the incident wave energy through wave breaking, whereas sand dunes provide the final natural barrier against coastal flooding. The storm impact on coastal areas with these features depends on the relative elevation of the extreme water levels with respect to the sand dune morphology. However, despite the importance of barrier reefs and dunes in coastal protection, poor management practices have degraded these ecosystems, increasing their vulnerability to coastal flooding. The present study aims to theoretically investigate the role of the reef–dune system in coastal protection under current climatic conditions at Puerto Morelos, located in the Mexican Caribbean Sea, using a widely validated nonlinear non-hydrostatic numerical model (SWASH). Wave hindcast information, tidal level, and a measured beach profile of the reef–dune system in Puerto Morelos are employed to estimate extreme runup and the storm impact scale for current and theoretical scenarios. The numerical results show the importance of including the storm surge when predicting extreme water levels and also show that ecosystem degradation has important implications for coastal protection against storms with return periods of less than 10 years. The latter highlights the importance of conservation of the system as a mitigation measure to decrease coastal vulnerability and infrastructure losses in coastal areas in the short to medium term. Furthermore, the results are used to evaluate the applicability of runup parameterisations for beaches to reef environments. Numerical analysis of runup dynamics suggests that runup parameterisations for reef environments can be improved by including the fore reef slope. Therefore, future research to develop runup parameterisations incorporating reef geometry features (e.g. reef crest elevation, reef lagoon width, fore reef slope) is warranted.


2021 ◽  
Vol 19 (1) ◽  
pp. 1-9
Author(s):  
Permana Ari Soejarwo ◽  
Rismawaty Rusdi ◽  
Taryono Kodiran ◽  
Umi Muawanah

Indonesia coastal areas have considerable natural disaster potential including in Kalianda District South Lampung Regency. Natural disasters such as earthquakes, tsunamis and volcanic activity are likely to occur in coastal areas. The disaster has an impact on economic losses in the marine tourism area. In order to mitigate tsunami disasters in the marine tourism area of Kalianda District, South Lampung Regency, 3 (three) types of tsunami mitigation are needed, namely: construction of coastal protection, installation of the Tsunami Early Warning System (TEWS) and planting of coastal vegetation. This study aims to determine the value of willingness to pay (WTP) of community and tourists in supporting the management of the three types of tsunami disaster mitigation above by using economic valuation / Contingent Valuation Method (CVM). The results of this study indicate that the WTP value of community for coastal protection management is Rp 15.547/person/month while the WTP value of tourist is Rp 12.030/one time entry. Meanwhile, for the WTP value of TEWS management is obtained Rp 12.174/person/month. WTP value for the management of coastal vegetation is Rp 12.444/person/month. The WTP calculation is based on consideration of 3 (three) factors, namely age, income, livelyhood and education level. This research shows that the community and tourists are willing to pay for the management of the three types of tsunami disaster mitigation through BUMDes and entrance fees for marine tourism area. The three types of tsunami disaster mitigation can protect, provide security and calm to the community and tourists in the marine tourism area of Kalianda District, South Lampung Regency from future tsunami.


2019 ◽  
pp. 84-114
Author(s):  
David Vogel

This chapter begins by exploring the conflicts over Southern California's beaches and coastal areas and then turns to efforts to protect the San Francisco Bay and the entire Pacific coast. In addition to its aesthetic value and opportunities for recreation, the coast is a major economic resource. It enhances the value of property located on or near it, and the coastal area also contains substantial deposits of oil. Precisely because the coast is a scarce and valuable resource with so many competing uses, protecting it, like the coastal redwoods, has been highly contentious. On one important dimension, the dynamics of two of the important cases described in this chapter depart from the book's explanatory framework. The campaigns to establish the Bay Conservation and Development Commission, the world's first coastal protection agency, as well as the more sweeping California Coastal Commission, received no business support. In both cases, the interests of business were not divided. Rather, their creation was made possible by extensive citizen mobilization, an outcome that reveals the important role played by public support for environmental protection in California beginning in the middle of the twentieth century.


2020 ◽  
Vol 8 (7) ◽  
pp. 510 ◽  
Author(s):  
Mario Maiolo ◽  
Riccardo Alvise Mel ◽  
Salvatore Sinopoli

Erosion processes threaten the economy, the environment and the ecosystem of coastal areas. In addition, human action can significantly affect the characteristics of the soil and the landscape of the shoreline. In this context, pursuing environmental sustainability is of paramount importance in solving environmental degradation of coastal areas worldwide, with particular reference to the design of complex engineering structures. Among all the measures conceived to protect the shoreline, environmentally friendly interventions should be supported by the stakeholders and tested by means of mathematical models, in order to evaluate their effectiveness in coastal protection through the evaluation of wave damping and bedload. This study focuses on protected nourishments, as strategic interventions aimed to counteract coastal erosion without affecting the environment. Here, we develop a simplified method to provide a preliminary assessment of the efficiency of submerged breakwaters in reducing wave energy at a relatively low computational cost, if compared to the standard 2D or full 3D mathematical models. The methodology is applied at Calabaia Beach, located in the southern Tyrrhenian Sea (Italy), in the area of the Marine Experimental Station of Capo Tirone. The results show that the simplified method is proven to be an essential tool in assisting researchers and institutions to address the effects of submerged breakwaters on nourishment protection.


2020 ◽  
Vol 12 (22) ◽  
pp. 3689
Author(s):  
Iain Fairley ◽  
Jose Horrillo-Caraballo ◽  
Ian Masters ◽  
Harshinie Karunarathna ◽  
Dominic E. Reeve

Coastal dunes have global importance as ecological habitats, recreational areas, and vital natural coastal protection. Dunes evolve due to variations in the supply and removal of sediment via both wind and waves, and on stabilization through vegetation colonization and growth. One aspect of dune evolution that is poorly understood is the longshore variation in dune response to morphodynamic forcing, which can occur over small spatial scales. In this paper, a fixed wing unmanned aerial vehicle (UAV), is used to measure the longshore variation in evolution of a dune system in a megatidal environment. Dune sections to the east and west of the study site are prograding whereas the central portion is static or eroding. The measured variation in dune response is compared to mesoscale intertidal bar migration and short-term measurements of longshore variation in wave characteristics during two storms. Intertidal sand bar migration is measured using satellite imagery: crescentic intertidal bars are present in front of the accreting portion of the beach to the west and migrate onshore at a rate of 0.1–0.2 m/day; episodically the eastern end of the bar detaches from the main bar and migrates eastward to attach near the eastern end of the study area; bypassing the central eroding section. Statistically significant longshore variation in intertidal wave heights were measured using beachface mounted pressure transducers: the largest significant wave heights are found in front of the dune section suffering erosion. Spectral differences were noted with more narrow-banded spectra in this area but differences are not statistically significant. These observations demonstrate the importance of three-dimensionality in intertidal beach morphology on longshore variation in dune evolution; both through longshore variation in onshore sediment supply and through causing longshore variation in near-dune significant wave heights.


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