Coastal Erosion Prevention Research Articles

A comprehensive approach to evaluate coastal dune evolution in Haiyang, China

Coastal dunes record the evolutionary process of coastal dynamic geomorphological systems, and provide valuable information on climate change, sea level changes, environmental evolution. These dunes are essential for global change research. In view of the dynamic changes in coastal dunes caused by extreme weather, coastal erosion and human activities, we propose a comprehensive evaluation method for coastal dune evolution, which monitors Haiyang Ten Thousand Meters Beach of China from three perspectives: point, line, and surface. This method integrates LiDAR, GNSS, and RS technologies. The research results indicate that between 2016 and 2018, 68% of the GNSS point measurements in 22 survey profiles of coastal dunes were eroded along the foreshore. During 2011-2020, the coastline based on the RS data basically remained stable; only the estuarine district underwent significant changes, and the overall average change rate was 1.32 m/a. The overall morphological evolution of coastal dunes obtained by LiDAR in 2018 was relatively stable, but there was a weak erosion trend in the foreshores of the coastal dunes. This study is beneficial for providing precise targets for remediating and restoring eroded coastal areas in the future. Furthermore, it can provide technical support and informational information for ecological environment protection, coastal erosion prevention and environmental evolution in the Haiyang Ten Thousand Meters Beach Marine Nature Reserve.

Ecosystem services for supporting coastal and marine resources management, an example from the Adriatic sea (Central Mediterranean sea)

Ecosystem Services (ESs) assessment is increasingly considered the constitutive metric to embrace the social, ecological, and economic spheres. Spatially explicit ES assessments can integrate and standardize different types of information, making them comparable. In this context, a multiple coastal and marine ESs assessment in the Northern-Central Adriatic Sea was carried out, considering seven ESs. Two cultural (tourism and recreational boating), two regulating (carbon sequestration and coastal erosion prevention potential), and three provisioning (mussel, whitefish aquaculture, and industrial fishery) ESs have been measured. The spatial analysis described (un)sustainable human uses of ecosystems in the area. (De)coupling of ES capacities and flows and synergies and tradeoffs among ESs were analyzed. Results indicate spatial agreement for capacities, while contrasting results emerged from the analysis across flows and of the capacity-flow balance. The evidence of a geographical pattern and areas of high, medium, and low capability to provide ESs across the study area was highlighted, suggesting the need for implementing the natural resources management. Some coastal provinces maximize a single ES at the detriment of other ESs, and other provinces built mimics of Nature through artificial facilities. These strategies are not far-sighted in the view of conserving the supply of the whole ESs set. These findings might be useful in the context of the Marine Strategy Framework Directive (MSFD), and for the implementation of the Maritime Spatial Planning (MSP) in the Northern-Central Adriatic Sea.

A Study on Developing Structural Measure for the Prevention of Coastal Erosion

The impact of coastal erosion has adversely affected the socioeconomic conditions of the coastal communityworldwide. The coastal environment is experiencing a wide range of natural and anthropogenic pressurein India. The coastal zone has been receiving increased attention due to pressure of population growth,developmental activities, trade and transport and presence of vital and critical habitats. Severe coastalerosion, loss of marine ecosystem, industrial pollution, sedimentations in harbours and portsare some ofthe major concerns to the coastal zone managers. Thus, the presented study identifies the effects of existingmethods and suggesting an inventive structural measure to prevent the coastal erosion. Further, the suggestedmeasure supports the development of marine ecosystem as intact as an artificial coral reef which improvesthe coastal community’slivelihoodsand sustenance of coastal ecosystem.

Topographical change assessment of tidal flats in Ha Long - Cam Pha, Quang Ninh using Landsat

Assessment of landform change in tidal flat is crucial for ecological environment protection, coastal erosion prevention and development likelihood for local people. Multi-temporal remote sensing images are useful data to detect the change of tidal flat. This study aims to assess intertidal topographic changes by comparing digital elevation model (DEM) from 1988 to 2014. The DEMs were generated from Landsat images from 1988÷1990; 2000÷2001 and 2013÷2014 using the waterline method. Correlation between DEM in 2013÷2014 and field data reached the value R of 0.821. The area variation of tidal flat topography is presented by spatial indicators. (1) the change of area of tidal flat such as high tidal flat, middle tidal flat, and low tidal flat using overlay analysis. (2) volume change of tidal flat were detected by subtraction from DEMs. The area of tidal flat decreased 25.56 ha which shows erosion from 1988÷2001. Overall, 1000m3 of sediment deposited on the high tidal flat was indicated.

Application of the Artificial Coral Reef as a Coastal Erosion Prevention Method with Numerical-Physical Combined Analysis (Case study: Cheonjin-Bongpo beach, Kangwon province, South Korea)

Application of the Artificial Coral Reef as a Coastal Erosion Prevention Method with Numerical-Physical Combined Analysis (Case study: Cheonjin-Bongpo beach, Kangwon province, South Korea)

Improved Coastal Erosion Prevention Using a Hybrid Method with an Artificial Coral Reef: Large-Scale 3D Hydraulic Experiment

Coastal erosion, a worldwide social issue, has garnered substantial attention. Numerous methods have been implemented to control coastal erosion problems; however, the presence of rigid structures limits erosion mitigation, thereby causing various challenges. For instance, in the case of submerged breakwaters, local scour in front of the structure and scour caused by the flow occurring in open inlets affect the subsidence and stability of the structure and can also cause structural failure. To solve these problems, this paper proposes a hybrid method of using a submerged breakwater with an artificial coral reef installation; further, this study evaluates the attenuation of waves and mitigation of sediment transportation through large-scale 3D hydraulic experiments. We found that the hybrid method with an artificial coral reef installed in the open inlet shows excellent wave control and plays a clearly beneficial role in the advancement of the shoreline. The artificial coral reef method reduced the return flow generated by the drag force at the breakwater shoulder and open inlet. In addition, scour at the breakwater shoulder was inhibited by collecting the sand escaping offshore. Simultaneously, scour at the open inlet was also mitigated. The application of the hybrid method compensated for the problems caused by local scour and erosion in the submerged breakwater, thereby leading to the improvement of its function. Therefore, the hybrid method proposed in this paper was determined to be applicable not only for submerged breakwaters, but also for various structures for controlling coastal erosion.

Estimation of Background Erosion Rate at Janghang Beach due to the Construction of Geum Estuary Tidal Barrier in Korea

In this study, a reduction in sediment budget due to the development of a river watershed, resulting in coastal erosion, was reviewed, and the rate of background erosion was calculated through an examination of the loss of coastal sediment into the open sea. The west coast of the Korean peninsula is severely impacted by the intercept of inflowing sediments from rivers, owing to the watershed development. However, the effects have not fully propagated into the entire coastal area, and thus, the long-term coastal erosion remains insignificant. However, a serious and irrevocable disaster may occur once the coastal erosion begins. Therefore, an analysis of the coastal erosion resulting from changes in the sediment budget, due to the development of the watershed, was conducted on Janghang Songrim Beach. A littoral cell of the Geum River was selected for a quantitative analysis of the decrease in the sediment budget from the watershed development. The rate of coastal sediment loss offshore, which reflects the characteristics of the Janghang Songrim Beach, and the future rate of coastal erosion were calculated. Then, the results were verified by employing geometrically corrected satellite photographs from previous years. This will enable us to predict the time of coastal erosion in the future due to a reduction in the sediment budget and watershed development, and prepare for future disasters resulting from the coastal erosion. Based on research into the components constituting the coastal development, the present study presents theoretical formulae allowing the prediction of the sediment budget and providing a practical contribution to the prevention of coastal erosion, for which additional reliable studies need to be conducted.

Impact of deforestation on mangrove tree diversity, biomass and community dynamics in the Segara Anakan lagoon, Java, Indonesia: A ten-year perspective

Indonesia has the largest area and the highest tree species richness but also one of the highest loss rates of mangroves worldwide. The Segara Anakan lagoon is a mangrove-fringed estuarine system in Java which is highly affected by deforestation, sedimentation, and land-use changes. The spatial variability of diversity, community composition, density, height, aboveground biomass and habitat complexity of the mangrove forest in relation to abiotic conditions was studied in 2014/2015. Vegetation characteristics were compared with those available from 2005/2006, and the effects of deforestation on the forest condition were assessed. In total, 15 mangrove tree species were recorded in 2015, six less than ten years ago. The two main areas of the lagoon, the central and eastern one, had a significantly different tree community composition. The central area was dominated by the palm Nypa fruticans and Aegiceras corniculatum and 74% of the ground was covered by the understorey plants Acanthus spp. and Derris trifoliata. Tree density, stand basal area, species number, aboveground biomass, and habitat complexity were significantly lower in the central area as a result of deforestation. Stand basal area and aboveground biomass decreased significantly over the 10 years as well as the density of Avicennia spp., Sonneratia spp., Ceriops spp., Aegiceras corniculatum, and Bruguiera spp. The eastern area was dominated by A. corniculatum and Rhizophora apiculata, and coverage with understorey plants was only 11%. The density of R. apiculata increased significantly over the 10 years as a result of natural regeneration and reforestation. The overall low tree height (2.8 m) and aboveground biomass (18.4 t dry mass ha−1) point to a young and degraded forest. In the central lagoon, mangrove reforestation is probably extremely difficult due to the strong expansion of understorey plants. It is assumed that ongoing deforestation will cause a further spread of understorey plants, a decrease in species number, tree density and habitat complexity. A decline in microhabitats and aboveground biomass can lead to a decrease of faunal species and biomass which in turn would influence nutrient cycling and impair the nursery function of the area. Also, important ecosystem services, particularly coastal protection against storms and prevention of coastal erosion are most likely affected.

Community Perceptions on Mangrove Forest Sustainability in Dukuh Bendo, Jatikontal Village, Purwodadi District, Purworejo Regency, Central Java

Mangrove forest has many functions, such as prevention of coastal erosion and seawater intrusion, reduce the risk of hurricane and tsunami, the place for spawning, nursery, and feeding grounds of marine biota, carbon storage, and direct use for human. However, many functions that mangrove has, unsustainable utilization of mangrove make the area of mangrove has decreased. The mangrove forest of Jatikontal, Purwodadi District, Jawa Tengah is studied as a case area that has suffered from degradation and declining the area during some years. Whereas, the south coast of Purworejo has a high risk of a tsunami. This research has aims to know the perception and behaviour of a community with the mangrove forest. The method of collecting data use the questionnaire giving to 30 respondents in Bendo, Jatikontal sub-district. Respondent is chosen with the purposive technique. The result of this study is as much 83.3% respondents have good perception, 16,7% respondents have moderate perception, and no respondent has a low perception of the sustainability of mangrove forests. Most of the community (66,7%) in Dukuh Bendo have a high concern for the preservation of mangrove forests. No single respondent is not concerned about the preservation of mangrove forests.

Amphibious Devices / Interventions that adapt to land and water in the protected area of Bask-Rrjoll, Shkodra

Albania went through an unprecedented population movement that followed the change of regime after 1990. A movement that manifested itself both internally and internationally, it had a huge impact on Albanian cities and territory. What is known today commonly as the informal settlements, those buildings came as a result of lack of control by the local authorities which were unable to either stop or direct development and the need for housing that followed the movement. This meant that the landscape and territory suddenly became overrun by self-built homes or business that changed the urban, rural and natural landscape. Many of these developments where pulled by the western cost which offered the possibility for a quick return in tourism. The protected landscape of Bune-Velipoja and in particular the area of Bask-Rjoll have become a hotspot also for the agricultural possibilities offered, thus starting the first settlements that would go and change the landscape itself. The result of human behavior and interaction in landscape has caused damage to its biodiversity and flora and fauna. By understanding how the population movement have affected the settling and quality of the landscape, the aim of this paper is to propose seemingly disconnected interventions that aim at preserving landscape, flood resilience, coastal erosion prevention and emphasizing the qualities of the landscape in order to re-evaluate the landscape as a touristic attraction. By including communities and giving them a sense of belonging to the landscape these preservations processes can become regenerative tools.

Development of New Coastal Erosion Countermeasure Using Wave Energy Control Method

Kang, Y.K. and An, S.H., 2018. Development of New Coastal Erosion Countermeasure Using Wave Energy Control Method. In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 1516–1520. Coconut Creek (Florida), ISSN 0749-0208.Coastal erosion has become a social issue around the world, including Korea. A Considerable number of coastal erosions have occurred along the East Sea in Korea, primarily caused by port and harbor developments. Countermeasures have generally utilized wave breaks with wide–low–crest submerged breakwater (so-called artificial reefs), which are coastal constructions emulating the wave absorbing effect of natural reefs with good wave–protection performance. However, these result in secondary damages such as scouring near openings and erosion towards the rear because of strong currents generated by wave setups. This study suggests a new countermeasure for coastal erosion by controlling wave energy differentiated by incident wave, i.e., wave direction control method (WDCM) to prevent the critical coastal erosion expected from a massive harbor expansion project planned along the east coast of Korea. The WDCM attempts to balance disparities in wave energy caused by harbor expansion to restrain imbalanced wave energies that result in imbalanced littoral drift. To accomplish this purpose, low crest structures are obliquely deployed at 250–300 m from the coastline to manipulate the wave energy by modulating incident wave direction. This new deployment method avoids excessive interference with the incident waves, and prevents resilience by leaving cross-shore sediment transport unhindered. In order to determine the effectiveness of the proposed WDCM, numerical computations were conducted evaluating its performance regarding coastal erosion prevention.

Role of Godrej Mangroves in Climate Change Mitigation through Carbon Sequestration.

Godrej and Boyce Mfg. Co. Ltd. is conserving thousands of acres of mangrove forest along the western bank of Thane Creek (19º03’31.12” N, 72º56’31.54” E to 19º06’31.43” N to 72º56’31.54” E) since the decade of 1940s. In this rich biodiverse forest, we have recorded 16 species of mangrove and mangrove associated plants. These forests provide ecosystem services like prevention of coastal erosion, habitat for wildlife, livelihoods for local fisherfolk, research and education avenue for academia and regulation of local climate. This paper explains material and methodology used to measure sequestered carbon using data of past 3 years. Annually this forest sequesters 6 lakh tons of CO2 its potential annual increment value iaround 50,000 tons of equivalent CO2. This carbon sequestration service is very valuable considering high emission of CO2 in the Mumbai Metropolitan Region and its impact on climate change. The paper also highlights importance of this project to the society and need to sensitize stakeholders for the mangrove conservation.

인공식생을 이용한 해빈침식방지에 관한 수리실험

인공식생을 이용한 해빈침식방지에 관한 수리실험

The Wave Attenuation Effect of Artificial Reef on Coastal Erosion Prevention

해안 침식은 환경문제임과 동시에 사회적 문제 중 하나로 인식되고 있다. 해안 침식을 제어하기 위한 대응책으로서 방파제나 잠제, 인공어초 등이 그 활용 방안으로 떠오르고 있고, 실제로 이러한 구조물들은 파랑 에너지를 감소시켜 해안 침식을 방지하는 역할을 한다. 이러한 긍정적인 효과에 기초하여, 많은 잠제형 구조물들이 연안에 설치되고 있다. 이러한 해안 구조물의 파랑 에너지의 감소 효과를 살펴보기 위해, 파랑 전달률(K)과 Ursell 수, 파형경사 및 수심관련 매개변수들과의 상관성을 분석하였다. 본 실험은 파랑 에너지의 소산 효과를 나타낸다. 실험결과, 잠제에 의한 파고 감쇠율은 3열의 경우에 대해 최대 19.2%로 나타났다. 아울러, 파랑 에너지의 전달률은 Ursell 수에 의해 표현되 는 실험식을 도출할 수 있다.

Above vs. belowground plant biomass along a barrier island: Implications for dune stabilization

Coastal regions are inherently and increasingly vulnerable and geomorphologically unstable, yet are invaluable economic and residential hubs. Dunes are dynamic buffers to erosion and the most natural, economical, and effective defense for coastal communities. Vegetation is integral to dune structure as it facilitates accretion and stabilization. Differences in the vegetation and root density likely translate to variability in coastal erosion prevention, but this notion has been largely unconsidered. We directly compared stabilizing factors, depth and density, of the root systems of two dominant mid-Atlantic dune plant species, native American beach grass (Ammophila breviligulata) and invasive Asiatic sand sedge (Carex kobomugi). Despite high plant density, C. kobomugi is targeted for removal in restoration efforts as its roots are assumed to provide less effective stabilization than A. breviligulata. We collected 30 cores and hand dug 14 A. breviligulata ramets at Island Beach State Park, New Jersey to examine biomass, root:shoot ratios, and root density. C. kobomugi had a more extensive root system with a root:shoot ratio of 11.36:1 compared to 1.62:1 for A. breviligulata. Similarly, cores 60 cm deep and 7.6 cm wide were sufficient to attain fully intact A. breviligulata roots, which did not extend deeper than 40 cm, but insufficient for C. kobomugi roots which extended beyond the sampling system vertically and horizontally. Scaling these findings to m−2, aboveground biomass is relatively equal, but C. kobomugi had over 700% more root mass m−2 than A. breviligulata. These results have strong implications for dune management. The root system of C. kobomugi may be better adapted to stabilize dunes and thus protect coastal areas during small and large-scale perturbations than previously supposed. This is a unique situation whereby the creation of monocultures will hyperstabilize dunes and make them more resistant to erosion at the cost of reduced biodiversity within the framework of resiliency.

BEACH VOLUME CHANGE USING UAV PHOTOGRAMMETRY SONGJUNG BEACH, KOREA

Abstract. Natural beach is controlled by many factors related to wave and tidal forces, wind, sediment, and initial topography. For this reason, if numerous topographic data of beach is accurately collected, coastal erosion/acceleration is able to be assessed and clarified. Generally, however, many studies on coastal erosion have limitation to analyse the whole beach, carried out of partial area as like shoreline (horizontal 2D) and beach profile (vertical 2D) on account of limitation of numerical simulation. This is an important application for prevention of coastal erosion, and UAV photogrammetry is also used to 3D topographic data. This paper analyses the use of unmanned aerial vehicles (UAV) to 3D map and beach volume change. UAV (Quadcopter) equipped with a non-metric camera was used to acquire images in Songjung beach which is located south-east Korea peninsula. The dynamics of beach topography, its geometric properties and estimates of eroded and deposited sand volumes were determined by combining elevation data with quarterly RTK-VRS measurements. To explore the new possibilities for assessment of coastal change we have developed a methodology for 3D analysis of coastal topography evolution based on existing high resolution elevation data combined with low coast, UAV and on-ground RTK-VRS surveys. DSMs were obtained by stereo-matching using Agisoft Photoscan. Using GCPs the vertical accuracy of the DSMs was found to be 10 cm or better. The resulting datasets were integrated in a local coordinates and the method proved to be a very useful fool for the detection of areas where coastal erosion occurs and for the quantification of beach change. The value of such analysis is illustrated by applications to coastal of South Korea sites that face significant management challenges.

BEACH VOLUME CHANGE USING UAV PHOTOGRAMMETRY SONGJUNG BEACH, KOREA

Natural beach is controlled by many factors related to wave and tidal forces, wind, sediment, and initial topography. For this reason, if numerous topographic data of beach is accurately collected, coastal erosion/acceleration is able to be assessed and clarified. Generally, however, many studies on coastal erosion have limitation to analyse the whole beach, carried out of partial area as like shoreline (horizontal 2D) and beach profile (vertical 2D) on account of limitation of numerical simulation. This is an important application for prevention of coastal erosion, and UAV photogrammetry is also used to 3D topographic data. This paper analyses the use of unmanned aerial vehicles (UAV) to 3D map and beach volume change. UAV (Quadcopter) equipped with a non-metric camera was used to acquire images in Songjung beach which is located south-east Korea peninsula. The dynamics of beach topography, its geometric properties and estimates of eroded and deposited sand volumes were determined by combining elevation data with quarterly RTK-VRS measurements. To explore the new possibilities for assessment of coastal change we have developed a methodology for 3D analysis of coastal topography evolution based on existing high resolution elevation data combined with low coast, UAV and on-ground RTK-VRS surveys. DSMs were obtained by stereo-matching using Agisoft Photoscan. Using GCPs the vertical accuracy of the DSMs was found to be 10 cm or better. The resulting datasets were integrated in a local coordinates and the method proved to be a very useful fool for the detection of areas where coastal erosion occurs and for the quantification of beach change. The value of such analysis is illustrated by applications to coastal of South Korea sites that face significant management challenges.

Mangrove forest decline: consequences for livelihoods and environment in South Sulawesi

Mangrove forests in the tropics and subtropics grow in saline sediments in coastal and estuarine environments. Preservation of mangrove forests is important for many reasons, including the prevention of coastal erosion and seawater intrusion; the provision of spawning, nursery, and feeding grounds of diverse marine biota; and for direct use (such as firewood, charcoal, and construction material)—all of which benefit the sustainability of local communities. However, for many mangrove areas of the world, unsustainable resource utilization and the profit orientation of communities have often led to rapid and severe mangrove loss with serious consequences. The mangrove forests of the Takalar District, South Sulawesi, are studied here as a case area that has suffered from degradation and declining spatial extent during recent decades. On the basis of a post-classification comparison of change detection from satellite imagery and a survey of households, we provide an estimate of the mangrove change in the Takalar District during 1979–2011 and the consequences of those changes. Mangrove forest areas were reduced by 66.05 % (3344 hectares) during the 33-year period of analysis, and the biggest annual negative change in dense mangrove forest cover (8.37 %) occurred during the period 2006–2011. The changes were caused mainly by the mangrove clearing and conversion to aquaculture, and consequences have been increasing forest degradation, coastal abrasion, seawater intrusion, a decline in fish capture, a reduction in juvenile shrimp and milkfish, and outbreaks of shrimp disease. On the other hand, the clearing and impoundment of mangrove forests for shrimp and seaweed culture have provided a source of foreign exchange and new opportunities for employment in the study area.

The economics of ecosystems and biodiversity, REDD+ and climate change in mangrove ecosystems of Southeast Asia

Mangroves are trees and shrubs that grow in saline coastal habitats. They occupy large stretches of the sub-tropical and tropical coastlines around the world. They not only provide valuable goods such as timber, fish and medicinal plants but also vital ecological services, such as prevention of coastal erosion. They also help buffer coastal communities from storms and floods. During the ASEAN Conference on Biodiversity held in Singapore in 2009, Ellison reported that mangrove forests in South East Asia are among the highest biodiversity resources in the world, occupying an area of 60.9 x 102 km2. Unfortunately, the region also has the highest rates of mangrove loss in the world, losing 628 km2 per year in two decades. In many parts of the world, where mangrove forests have been cleared, there are now problems of erosion and siltation, and loss of life and property have occurred due to destructive hurricanes, storms and tsunamis. The complex relationship between climate change and mangrove ecosystems can be seen from two different angles. On the one hand, mangrove ecosystems have a critical function in combating climate change; on the other hand, they are affected by climate change. The values of ecosystems vary according to local biophysical and ecological circumstances and the social, economic and cultural context. Intangible values, which may be reflected in society’s willingness to pay to conserve particular species or landscapes, or to protect common resources, must be considered alongside more tangible values such as food or timber to provide a complete economic picture. This has important implications for mangrove conservation strategies and suggests that the preservation of contiguous areas is preferable to patches that are spatially dispersed.

シルト質内湾での現地特性を活かした海岸侵食対策の検討

In many coasts of Thailand, serious coastal erosion has occurred and breakwaters for preventing it have been constructed. Especially since many coasts in the gulf of Thailand consist of very fine bed materials, wave dissipation breakwaters made of bamboo piles and detached breakwaters made of geotextile bags which were packed bed materials have been constructed instead of concrete block breakwaters. However, these arrangement plans were based on empirical techniques. This research examines the validity of the effect evaluation method of the coastal erosion prevention using a numerical prediction model. Moreover, the comparison of the bamboo pile breakwater and the geotextile detached breakwater shows that the former can acquire sufficient effect for the erosion prevention with construction costs cheaper a little than the latter.