Coastal Structures as Beach Erosion Control and Sea Level Rise Adaptation in Malaysia: A Review

Advancing coastal resilience: Coastal vulnerability assessment using cutting-edge space geodetic and optical imaging techniques

Space geodetic and optical imaging techniques are employed to assess the coastal vulnerability index (CVI) in order to adapt to the contemporary approach to coastal classification. Satellite altimeter, Satellite Pour l'Observation de la Terre (SPOT) and integrated multi-satellite retrievals for GPM (IMERG) were among the satellite data used. The variables were deemed adequate based on the spatiotemporal estimates, then were quantified through expert-weighted scores and integrated into a single index over the Terengganu coastal area. The CVI findings performed better with eight variables, showing higher overall accuracy (70.83%), Kappa coefficient (59.02%), and area under curve (AUC) (0.8) than the conventional six variables. Vulnerability rankings are distributed relatively evenly across the Terengganu coast, with the moderate (2) ranking being the most predominant at 27.2% of the total area. Space geodetic and optical imagery techniques prove highly beneficial to CVI assessment, offering a viable alternative to traditional methods, especially for broader-scale coastal management.

Architected materials for artificial reefs to increase storm energy dissipation

Increasing extreme weather events require a corresponding increase in coastal protection. We show that architected materials, which have macroscopic properties that differ from those of their constituent components, can increase wave energy dissipation by more than an order of magnitude over both natural and existing artificial reefs, while providing a biocompatible environment. We present a search that optimized their design through proper hydrodynamic modeling and experimental testing, validated their performance, and characterized sustainable materials for their construction.

The impact of climate change on coastal erosion in Southeast Asia and the compelling need to establish robust adaptation strategies

Climate change alters the climate condition and ocean environment, leading to accelerated coastal erosion and a shift in the coastline shape. From previous studies, Southeast Asia's coastal region is suffering from severe coastal erosion. It is most sensitive and vulnerable to climate change, has broad and densely populated coastlines, and is under ecological pressure. Efforts to systematically review these studies are still insufficient despite many studies on the climate change linked to coastal erosion, the correlation between coastal erosion and coastal communities, and the adaptative measures to address these issues and their effectiveness in Southeast Asia. Therefore, by analyzing the existing literature, the purpose of this review was to bridge the knowledge gap and identify the link between climate change and coastal erosion in Southeast Asia in terms of sea-level rise, storm surge, and monsoon patterns. The RepOrting standards for Systematic Evidence Syntheses (ROSES) guided the study protocol, including articles from the Scopus and Dimension databases. There were five main themes considered: 1) climate change impact, 2) contributing factors to coastal erosion, 3) coastal erosion impact on coastal communities, 4) adaptation measure and 5) effectiveness of adaptation measure using thematical analysis. Subsequently, nine sub-themes were produced from the themes. Generally, in Southeast Asia, coastal erosion was reflected by the rising sea level. Throughout reviewing past literature, an interesting result was explored. Storm surges also had the potential to affect coastal erosion due to alterations of the atmospheric system and seasonal monsoon as the result of climate change. Meanwhile, an assessment of current erosion control strategies in relation to the relative hydrodynamic trend was required to avoid the failure of defence structures and the resulting danger to coastal communities. Systematically reviewing the existing literature was critical, hence it could significantly contribute to the body of knowledge. It provides valuable information for interested parties, such as authorities, the public, researchers, and environmentalists, while comprehending existing adaptation practices. This kind of review could strategize adaptation and natural resource management in line with coastal communities' needs, abilities, and capabilities in response to environmental and other change forms.

A review of the management of water resources in Malaysia facing climate change

This paper reviewed the impacts of climate change on the management of the water sector in Malaysia discussing the current status of water resources, water service, and water-related disasters. The implementation of engineering practices was discussed to provide the detailed assessment of climate change impacts, risks, and adaptation for sustainable development. The narrative methods of reviewing the literatures were used to get an understanding on the engineering practices of water infrastructures, implication of the government policies, and several models as the main motivation behind the concept of integrated water resource management to contribute as part of the sustainable development goals to achieve a better and more sustainable future for all. The findings of this review highlighted the impacts of climate change on the rivers, sea, lakes, dams, and groundwater affecting the availability of water for domestic and industrial water supplies, irrigation, hydropower, and fisheries. The impacts of climate change on the water-related disasters have been indicated affecting drought-flood abrupt alternation and water pollution. Challenges of water management practices facing climate change should be aware of the updated intensity-duration-frequency curves, alternative sources of water, effective water demand management, efficiency of irrigation water, inter-basin water transfer, and nonrevenue water. The transferability of this review findings contribute to an engagement with the society and policy makers to mobilize for climate change adaptation in the water sector.

Seasonal benthic species composition linked to coastal defense structures (CDS) in Kuala Nerus, Terengganu, Malaysia

Background

The natural hydrodynamic process of Kuala Nerus, Terengganu, has changed since the extension of Sultan Mahmud Airport runway in 2008. Consequently, severe coastal erosion has occurred in the area, particularly during the northeast monsoon season (NEM). Numerous types of coastal defense structures (CDS) have been constructed to protect the coastline. Despite the loss of esthetic values, the effect of CDS construction on marine organisms in the area remains unknown. Hence, this study aims to assess the ecological aspects of macrobenthic compositions at the CDS area of Kuala Nerus, Terengganu, based on the differences between the southwest (SWM) and northeast (NEM) monsoon seasons.

Methods

Macrobenthos were collected from the sediment in July (SWM) and December 2021 (NEM) using the Ponar grab at 12 substations from five sampling stations.

Results

The density of macrobenthos was higher in SWM (48,190.82 ind./m2) than in NEM (24,504.83 ind./m2), with phylum Mollusca recording the highest species composition (60-99.3%). The macrobenthos species had a low to moderate level of diversity (H' = 1.4-3.1) with the species were almost evenly distributed (J' = 0.2-0.8). Windward substations exhibited coarser grain sizes (38.56%-86.84%), whereas landward substations exhibited very fine grain sizes (44.26%-86.70%). The SWM season recorded a higher organic matter content (1.6%-6.33%) than the NEM season (0.4%-3.1%). However, metal concentrations in the surface sediment were within the safe range and permissible limits for both seasons, inferring that the macrobenthos composition was unaffected.

Discussion

This study demonstrated that the CDS associated with the monsoon system has controlled the hydrodynamics and nearshore sedimentary processes in the Kuala Nerus coastal zone, thereby affecting the macrobenthos population, in terms of richness and density. The ecological and energetic effects of the coastal structures in different seasons have resulted in a more significant result, with the SWM exhibiting a higher macrobenthos composition than the NEM.

Spatiotemporal distribution of microplastics in Miri coastal area, NW Borneo: inference from a periodical observation

The current study aims to investigate the spatiotemporal distribution of microplastics (MPs) in the Miri coast, targeting their occurrences, characterisation, and potential sources. For a periodical study, coastal sediments were collected from three different time intervals (monsoon, post-monsoon, and post-COVID) and subjected to stereomicroscope, ATR-FTIR, and SEM-EDX analyses. These results show a significant increase of MPs in post-COVID samples by approximately 218% and 148% comparatively with monsoon and post-monsoon samples, respectively. The highest concentration of MPs was detected near the river mouths and industrial areas where the waste discharge rate and anthropogenic activities dominate. Fibre-type MPs are the most abundant, with an average of nearly 64%, followed by fragments, films, microbeads, and foams. The most dominant polymer types were polytetrafluoroethylene (PTFE), polyethylene (PE), polypropylene (PP), polystyrene (PS), and polyester (PET). Overall, the current study shows a better understanding of MPs occurrence and potential sources in the Miri coastal area.

Environmental impacts of shore revetment

Coastal structures, especially revetments, have been widely implemented to protect properties and infrastructures from erosive waves during storms. While being incompatible with nature-based solutions, revetments have still been constructed due to their effectiveness in solving coastal erosion. One of the most crucial concerns that should be considered as part of a revetment implementation is how to diminish and manage its possible impacts on the environment. Thus, a thorough understanding of how the revetments affect the surrounding environment must be achieved. This article critically reviews and summarizes their economic considerations, and environmental impacts on beach morphology, hydrodynamics, ecology, aesthetics, beach accessibility, beach recreation, and other notable aspects. Coastal practitioners and researchers, who are involved with the revetments, may increase their environmental awareness before implementing them. The revetments can be an excellent option to protect the eroding shoreline, if their possible environmental consequences are well-understood and properly managed.

Adaptation of coastal defence structure as a mechanism to alleviate coastal erosion in monsoon dominated coast of Peninsular Malaysia

The complexity of the coastal environment and the advent of climate change cause coastal erosion, which is incontrovertibly a significant concern worldwide, including Peninsular Malaysia, where, the coast is threatened by severe erosion linked to anthropogenic factors and monsoonal wind-driven waves. Consequently, the Malaysian government implemented a mitigation plan using several coastal defence systems to overcome the coastal erosion problem. This study assesses coastal erosion management strategies along a monsoon-dominated coasts by evaluating the efficacy of coastal protection structures against the coast. To this end, we analysed 244 km of the coastline of Terengganu, a federal state located on the east coast of Peninsular Malaysia. Due to a higher frequency of storms and the ensuing inception of high wave energy environments during the northeast monsoon (relative to southwest monsoon), the study area is the most impacted region in Malaysia with regard to coastal erosion. Fifty-five (55) coastal defence structures were detected along the Terengganu coastline. The Digital Shoreline Analysis System (DSAS) was utilised to compute changes in the rate statistics for various historical shoreline positions along the Terengganu coast to assess the efficacy of the defence structures. Additionally, this study acquired the perception of the existing coastal management strategies through an interview session with the concerned stakeholders. The rate statistics revealed the effectiveness and impact of the coastal defence structure on the coastline. Assessing the functionality of the coastal defence structures shed light on the present scenario of coastal erosion management. Greater efficacy and lower impact of coastal defence structures are prescribed for coastal erosion management strategies across the monsoon-dominated coast.

Environmental impact of submerged and emerged breakwaters

Coastlines are constantly threatened by erosion. Effective coastal defense structures with the least environmental impacts are increasingly required. Submerged and emerged breakwaters have been implemented globally, while positively or negatively creating impacts on the environment. One of the most significant concerns in applying breakwaters is how to minimize their undesirable consequences on the environment. Thus, a thorough understanding of how submerged and emerged breakwaters affect the surrounding environment must be achieved. This article critically reviews and summarizes their environmental impacts on beach morphology, hydrodynamics, ecology, tourism, and recreation, as well as other notable impacts. This is a review article that may help coastal practitioners to manage coastal erosion with breakwaters more sustainably.

Coastal Vulnerability: A Brief Review on Integrated Assessment in Southeast Asia

Coastal zones are an essential part of maintaining sustainability in the world. Coastal regions have gained importance due to various factors, including high ecological production, dense population, industry compatibility, waste disposal, leisure, transportation, and development of military strategies. Coasts are often on the move and must adapt while nature constantly works to maintain balance. Southeast Asia has gained prominence due to its rich ecosystem, high productivity, and densely populated coastal region. In light of this, the coastlines of Southeast Asia are threatened by various factors, including global climate change and human activities. These factors exacerbate the shoreline erosion, frequent catastrophic events, rising sea levels, and saltwater intrusion. Coastal management has become one of the most important challenges of the past decade. The coastal vulnerability index (CVI) was developed to identify and manage vulnerable locations along the coast. Thus, this review attempts to summarize coastal vulnerability in Southeast Asian based on journals and reports. Topics covered include: (1) introduction to coastal vulnerability, (2) methods for determining coastal vulnerability, (3) factors influencing coastal vulnerability (4) associated coastal vulnerability, (5) assessment gaps, and (6) further courses of action. Consequently, assessment of coastal vulnerability will support Southeast Asian coastal communities in guiding mitigation strategies to manage coastal threats in future climate change and urban development.

Natural and Anthropogenic Factors Shaping the Shoreline of Klaipėda, Lithuania

Port of Klaipėda is situated in a complex hydrological system, between the Curonian Lagoon and the Baltic Sea, at the Klaipėda strait in the South-Eastern part of the Baltic Sea. It has almost 300 m of jetties separating the Curonian Spit and the mainland coast, interrupting the main path of sediment transport through the South-Eastern coast of the Baltic Sea. Due to the Port of Klaipėda reconstruction in 2002 and the beach nourishment project, which was started in 2014, the shoreline position change tendency was observed. Shoreline position measurements of various periods can be used to derive quantitative estimates of coastal process directions and intensities. These data can be used to further our understanding of the scale and timing of shoreline changes in a geological and socio-economic context. This study analyzes long- and short-term shoreline position changes before and after the Port of Klaipėda reconstruction in 2002. Positions of historical shorelines from various sources were used, and the rates (EPR, NSM, and SCE) of shoreline changes have been assessed using the Digital Shoreline Analysis System (DSAS). An extension of ArcGIS K-means clustering was applied for shoreline classification into different coastal dynamic stretches. Coastal development has changed in the long-term (1984–2019) perspective: the eroded coast length increased from 1.5 to 4.2 km in the last decades. Coastal accumulation processes have been restored by the Port of Klaipėda executing the coastal zone nourishment project in 2014.

Recent Progress of Rice Husk Reinforced Polymer Composites: A Review

Recently, because of the rising population, carbon overloading, and environmental distress, human beings have needed to increase awareness and responsibility for the reduction of agricultural waste. The utilization of agricultural waste as a filler material in reinforced polymers is a fascinating discovery. This review paper attempts to study the physical, mechanical, and thermal behavior of rice husk (RH) as a fiber for reinforcing various synthetic polymers, based on recent studies, conducted between 2017 and 2021. It also highlights that advanced modification techniques could further improve the performance of composites by tailoring the physical and chemical substances of the fiber or matrix. The thermal properties, including flame-retardance and thermal behavior, are also discussed. The characteristics of the fiber–matrix interaction between RH and the polymer matrix provide essential insights into the future-ready applications of this agricultural waste fiber. The way forward in researching RH polymer composites is finally reviewed.