Coastal Buffer Research Articles

Challenges of Transforming Coastal Buffer Zones into Urban Systems and their Sustainable Development Management: Case of Lake Issyk-Kul

Challenges of Transforming Coastal Buffer Zones into Urban Systems and their Sustainable Development Management: Case of Lake Issyk-Kul

A novel Slepian approach for determining mass-term sea level from GRACE over the South China Sea

Treatment of land-to-ocean leakage is crucial in modeling the mass-term sea level (MSL) using the Gravity Recovery and Climate Experiment (GRACE) satellite gravity measurements. In this study, we utilized the Spherical Slepian functions (SSFs) to determine MSL variations in the South China Sea. A sensitivity simulation in terms of trend, annual amplitude, and phase revealed that the SSF solution with a 1° coastal buffer zone provides a better land-to-ocean leakage correction than traditionally used Spherical Harmonics (SH). It was also found that an additional smoothing procedure for SSF with low concentrating energy could significantly reduce the high-frequency noise in GRACE (e.g., the north–south strips). The spatiotemporal characteristics of the true MSL were further compared among GRACE SH and Mascon solutions, model-predicted ocean bottom pressure, and steric-corrected altimetric data (i.e., satellite-altimetric sea level minus steric effect). Results revealed that despite the SSF-inverted regional MSL solution being generally similar to other results, this technique notably recovered the realistic magnitude of detailed features. The apparent MSL signal was, for instance, precisely recovered in the central part of the Gulf of Thailand and the Sunda Shelf by the SSF, while the SH significantly underestimated it due to smoothing. In addition to the seasonality, the interannual signal decomposed from the SSF-inverted residual MSL (by removing the trend and periodic signals) was the strongest and well cross-correlated with the Southern Oscillation Index. With more detailed spatial patterns revealed by MSL from GRACE SSF, our findings demonstrate that SSF is more suitable for regional-scale studies.

Landcover-based detection of rapid impacts of extreme storm on coastal landscape

On September 24, 2022, Post-Tropical Hurricane Fiona made landfall in Atlantic Canada and caused unprecedented damages to the coastal communities and ecosystems therein. The aftermath triggered local government and communities in Prince Edward Island (PEI), Canada to rethink current policies and practices for coastal protection in the context of climate change. This historic hazard represents the escalating frequency and intensity of extreme weather events that globally threaten coastal regions, accelerating coastal erosion and endangering communities. This study employs landcover-based detection to assess rapid storm impact of Fiona on coastline of PEI using Sentinel-2 satellite images, to gauge the efficacy of landcover-based detection and quantify storm-induced coastal environmental changes. Our results indicate that, following Fiona, over 51 km2 coastal land loss due to the erosion at beach foreshore and inundation at tidal flat, and over 11 km2 sand dune loss mainly on the PEI north shore. This constitutes a 3.5 % loss of coastal land resources within the 1798 km2 PEI coastal zone. Fiona also caused over 194 km2 area in coastal buffer zone showed temporal fluid-mud from the eroded sediments of sand dunes, cliffs, and tidal flats, suggesting the significant sediment loss from vertical structures in addition to the direct retreat. The landcover-based method can be regarded as a valuable tool for the storm impacts on coastal environments. Based on the coastal change pattern, more sustainable coastal protection and adaptation measures should be developed, focusing on reducing hydrodynamic intensity and improving erosion capacity, with consideration of the increasing likelihood of more intense and frequent storm events in a warming climate.

Functional Assessment of Coastal Buffer Zone Installation by Numerical Method

Functional Assessment of Coastal Buffer Zone Installation by Numerical Method

ShoreScape

Urbanized sandy shores around the world suffer from coastal erosion due to a lack of sediment input and sea level rise. These dynamics place new demands on coastal spatial planning. To compensate for coastal erosion in a more natural and systemic way, sand nourishments are deployed as a ‘Building with Nature’ technique, restoring the sediment balance and promoting dune formation as coastal defence. In this research, Building with Nature is reframed as a landscape approach, regenerating the coastal landscape by tuning the interactions between the geomorphological, ecological, and urban system, to adapt to sea level rise. To this end, design principles have been developed that integrate nourishment dynamics, natural succession, and adaptive urban design to build towards safe and multi-functional coastal landscapes— Shore-Scapes. They focus on spatial coastal configurations utilizing wind-driven sedimentation processes to build up the coastal buffer, supporting dune formation, multifunctionality, and landscape differentiation. To direct sediment dynamics for coastal reinforcement and landscaping, three subsequent tools for dynamic design have been derived: morphogenesis, dynamic profiling, and aeolian design principles. With these principles, validated by fieldwork, GIS, and computational modelling, spatial arrangements can be composed enhancing the aeolian build-up of the coastal landscape over time. These principles were applied and contextualized in four case studies along the Dutch coast. They illustrate how dunes along urbanized shores can grow naturally after nourishment and allow coastal safety, recreation, and nature to complement each other.

Spatial-Temporal Effect of Sea–Land Gradient on Land Use Change in Coastal Zone: A Case Study of Dalian City

Geographically, the coastal zone is a unit where the marine system and the terrestrial system intersect and have the closest relationship with human survival and development. The study of coastal-zone land use change is therefore of great significance in promoting the sustainable development of coastal areas in terms of resources and environment. However, the relationship between urban land use change and distance from the coastline is indeterminate in current research. This paper aims to assess the spatial and temporal characteristics of coastal land use change with the sea–land gradient, as well as to reveal the role of coastal ecosystems. The indices of the dynamic index, net transfer matrix, and aggregation index were measured in different coastal buffer zones quantitatively. A case study of Dalian between 2000 and 2015 indicates that Dalian’s urban construction land is distributed among the coastal zones with a high total and fast growth rate. The land use conversion direction varies significantly between different buffer zones, with [0, 2.5] km tilted mainly towards urban types and [10, Max] km tilted mainly towards rural areas. The aggregation of land use structure in Dalian fluctuated and increased year by year. As the distance from the coastline gets closer, land use is going to get more diverse.

Accurate mapping of Chinese coastal aquaculture ponds using biophysical parameters based on Sentinel-2 time series images

Aquaculture plays a crucial role in the global food security and nutrition supply, where China accounts for the largest market share. Although there are some studies that focus on large-scale extraction of coastal aquaculture ponds from satellite images, they have often variable accuracies and encounter misclassification due to the similar geometric characteristics of various vivid water bodies. This paper proposes an efficient and novel method that integrates the spatial characteristics and three biophysical parameters (Chlorophyll-a, Trophic State Index, and Floating Algae Index) to map coastal aquaculture ponds at a national scale. These parameters are derived from bio-optical models based on the Google Earth Engine (GEE) cloud computing platform and time series of high-resolution Sentinel-2 images. Our proposed method effectively addresses the misclassification issue between the aquaculture ponds and rivers, lakes, reservoirs, and salt pans and achieves an overall accuracy of 91 % and a Kappa coefficient of 0.83 in the Chinese coastal zone. Our results indicate that the total area of Chinese coastal aquaculture ponds was 1,039,214 ha in 2019, mainly distributed in the Shandong and Guangdong provinces. The highest aquaculture intensity occurs within the 1 km coastal buffer zone, accounting for 22.4 % of the total area. Furthermore, more than half of the Chinese coastal aquaculture ponds are concentrated in the 0–5 km buffer zone. Our method is of general applicability and thus is suitable for large-scale aquaculture ponds mapping projects. Moreover, the biophysical parameters we employ can be considered as new indicators for the classification of various water bodies even with different aquaculture species.

Land management on small islands based on settlement distribution patterns: studies on Sulabesi Island, Indonesia

With limited land availability, the land use and management on the small island must be sustainable. Sulabesi Island, with an area of <2000 km<sup>2</sup>, makes it one of the small islands in North Maluku and a remote island. This condition makes Sulabesi vulnerable to land loss and faced with adverse threats both environmentally and socio-economically if the allocation of residential places does not manage appropriately. The study aimed to identify the distribution of coastal settlement land with the characteristics of the island landscape, including analyzing its suitability to coastal boundaries and recommending directions for the development of coastal settlements on Sulabesi island. The method of this study used the geographic information system (GIS) to provide a spatial picture with overlaying and buffering techniques. The data analysis used topography, slope, distribution of settlements, and coastlines with collected data sources from government agencies and remote sensing, including field observations. The analysis results showed that the settlements scattered Sulabesi island randomly and separately with linear patterns, clustering, and combinations. The distribution in the island landscape was with a dominant height at 0-200 m and a slope of 0-30% or is a flat-steep plain. Besides that also shows a mismatch of utilization between the residence and the coastal border area, so land use for future settlements can do on the more proportional ground, especially outside the coastal buffer area. The results of this study's analysis can be used for further direction in regional planning and land management on small islands.

Coastal buffer distances and secondary sonic booms

This presentation describes how secondary sonic booms have influenced our understanding of appropriate coastal buffer distances for supersonic aircraft. The International Civil Aviation Organization issued its Circular 126 in 1975 after the completion of test flights for the supersonic aircraft Concorde but before it began routine operations. This guidance was to prepare everyone for Concorde’s introduction. Particularly Chapter 5 recommended that a supersonic aircraft over the ocean should slow down to subsonic speeds at least 45 nautical miles before reaching the coastline, providing a coastal buffer distance to keep the sonic boom off of land. However, when Concorde began regular transatlantic service, the phenomenon of secondary sonic booms was better appreciated. Air France and British Airways changed their operations to provide much larger coastal buffer distances on the order of 150 nautical miles. Increasing the coastal buffer distances was successful in enabling routine Concorde operations. Implications for the introduction of future civilian supersonic aircraft are described. [Work funded by the FAA through ASCENT Project 57. Any opinions, findings, conclusions or recommendations expressed in this material are those of the author and do not necessarily reflect the views of the FAA.]

Protective Effects of Existing Coastal Buffers on Mitigating Cyclonic Impacts in Bangladesh

Protective Effects of Existing Coastal Buffers on Mitigating Cyclonic Impacts in Bangladesh

Planning and Management of Coastal Buffer Zones in Taiwan

Overuse of coastal regions may lead to coastal erosion and shoreline retreat, threatening the inherent life and property of the coast. This is because typhoon waves with storm surges frequently attack overdeveloped coasts and related structures. In the present study, coastal buffer and protection zones were defined for the management of coastal disasters. The coastal buffer zone may offer remarkable advantages to avoid improper coastal use and limit the impact of extreme events by reducing erosion, mitigating coastal disasters, improving water quality, expanding habitats, and minimizing coastal degradation. Further, factors affecting the establishment of coastal buffer zones were classified according to natural and anthropogenic characteristics. Moreover, regarding the direction of research into coastal buffer zones, themes and countermeasures for coastal buffer zone management were discussed from the perspectives of technology, planning, and management policies. Finally, the application of numerical models to assess the impact factors in coastal buffer zones are proposed.

CRESI: A susceptibility index methodology to assess roads threatened by coastal erosion

A new method is proposed to assess the susceptibility of coastal roads to structural deterioration from shoreline erosion caused by natural processes such as waves, tides, and the effects of climate change, including sea level rise. The approach is based on a new susceptibility index method called the Coastal Road Erosion Susceptibility Index (CRESI) that incorporates key parameters that control road structure and coastal buffer resistance to erosion and impacts from the ocean side. The index was applied to a network of Hawaii State roads and an extensive set of field data and observations were collected throughout all the major islands. This data has been cataloged into a database of coastal road assets that continues to be expanded. Over 300 sites were assessed as part of the project. Based on the value of CRESI, vulnerable road sections were segmented into one of three levels of erosion susceptibility. In addition, the twenty most vulnerable locations were ranked, based largely on the CRESI index, for purposes of road management and planning. Ongoing work relating to improvements in the methodology to better account for traffic and a more accurate set of natural (ocean) processes with a potential hazard risk are also described. The proposed new methodology can be applied to other regions with only minor adjustments for local boundary conditions, if necessary. The results of the applied new method from Hawaiian state roads show that the methodology proves useful and promising for government-, state-, and county-level road authorities and agencies in the assessment of the coastal road erosion problems and their decision making with regard to corresponding remediation measures.

Impacts of coastal land use change in the wet tropics on nearshore coral reefs: Case studies from Papua New Guinea

Logging and plantation agriculture are vital to economies and livelihoods in tropical nations, including Papua New Guinea. To meet global demand, hundreds of thousands of ha of diverse natural habitat have been logged, cleared and replaced with monoculture crops. Resulting hydrological changes have increased sediment, nutrient and pesticide runoff, impacting down-stream habitats. Here, case studies from Kimbe Bay (New Britain) and Mullins Harbour (Milne Bay), examine effects on nearshore coral reefs. In both places, logging and oil palm development had destabilized soils and removed or degraded riparian vegetation. Downstream, nearshore reefs had high silt levels, which, coincident with minor coral bleaching and predation by crown-of-thorns starfish, were correlated with high levels of coral mortality and low coral species richness. Sediment and related impacts can be reduced by effective catchment management, such as avoiding steep slopes, expanding stream and coastal buffer zones, minimizing fertilizer and pesticide use, monitoring and reactive management.

Coastal Buffer Zone Management in Banten Province Coastal Region During The December 2018 Tsunami Waves in The Sunda Strait

Natural disasters in coastal areas and small islands in Indonesia occurred several times in the last decade. Banten Province coastal region was directly affected by the tsunami waves last December 2018 due to the Anak Krakatau Volcano’s activities, covering Pandeglang and Serang Regencies. Regional and spatial planning in a coastal buffer zone is mandated by laws and regulations, both central and local, but still sometimes neglected. The spatial analysis was carried out by identifying land use/cover in Banten Province coastal area using high and medium resolution images acquired from the Google Earth website. The results of the land use/cover map observations, which validated with field data, showed that the built-up area from the tourism sector in the form of buildings, facilities, and infrastructures dominate the coastal buffer zone, both in Pandeglang and Serang Regencies, especially in Anyer District (22.3 ha), Carita District (10.7 ha), and Cinangka District (7.2 ha). Moreover, human settlements and supporting public facilities also contribute and dominate the built-up area on the coastal buffer zone in Panimbang District (15.8 ha) and Sumur District (6.4 ha). Implementation of a coastal buffer zone in a vulnerable area such as Banten Province should be evaluated to minimize the impact in the future.

Urban dunes

Sandy shores worldwide suffer from coastal erosion due to a lack of sediment input and sea-level rise. In response, coastal sand nourishments are executed using ‘Building with Nature’ techniques (BwN), in which the sand balance is amplified and natural dynamics are instrumental in the redistribution of sand, cross- and alongshore. These nourishments contribute to the growth of beaches and dunes, serving various design objectives (such as flood safety, nature, and recreation). Nevertheless, human interference (such as buildings and traffic) along urbanized sandy shores may have significant, yet poorly understood, effects on beach and dune development. Better insight is required into the interplay of morphological, ecological and urban processes to support Aeolian BwN processes for dune formation and contribute to the sustainable design of urbanized coastal zones. This paper aims to bridge the gap between coastal engineering and urban design by formulating design principles for BwN along urbanized sandy shores, combining nourishments, natural dune formation and urban development on a local scale to strengthen the coastal buffer. The first part of the paper analyses sedimentation processes in the (built) sea-land interface and identifies spatial mechanisms that relate coastal occupation to dune formation. Hence a preliminary set of design principles is derived by manipulating wind-driven sediment transport for BwN dune formation after nourishment. In the second part of the paper, these principles are applied and contextualized in two case-studies to compare their capability for BwN in different coastal profiles: the vast, rural, geomorphologically high dynamic profile of a mega-nourishment (Sand Motor); versus the compact, highly urbanized, profile(s) of a coastal resort (Noordwijk). Conclusions reflect on the applicability of BwN design principles within different coastal settings (dynamics, urbanity) and spatial arrangements facilitating BwN dune formation.

GIS-Based Assessesment of the Romanian Marine and Coastal Areas Hydrodynamical Characteristics as Part of Maritime Spatial Planning

"The Romanian coastal zone is strongly impacted by the marine processes, inducing a continuous emergent process nearly the sea-land interface. The sustainable anthropogenic development of the coastal zone is requiring the preservation of the natural landscape, respectively the natural characteristics and processes belonging of its specificity within different regional coastal areas, including marine natural reserves and marine protected areas/MPAs.Thus, the development and preservation of the marine activities within coastal water bodies, as well as coastal buffer areas, with specific measure of coastal protections or erosion control works, had become an activity of foremost interest.In this regard, the new methodologies and tools of the remote sensing and Geographic Information Systems/GIS were applied to support the monitoring of the natural factors within regional coastal and maritime planned areas with intense development within Romanian Exclusive Economic Zone/EEZ. Certain results and positive effects on MSP Directive implementation, based largely on various data, are accessible in the present work, in relation with reduction of the ecological impact of the different socio-economic activities, including coastal and maritime transportation, as well as specifically designation of the coastal and marine locations for the installations of the marine energy convertors. Key-Words: GIS, remote sensing, marine and coastal waves, wave energy, MSP "

Gravitationally Consistent Mean Barystatic Sea Level Rise From Leakage‐Corrected Monthly GRACE Data

AbstractGravitationally consistent solutions of the Sea Level Equation from leakage‐corrected monthly‐mean GFZ RL06 Gravity Recovery and Climate Experiment (GRACE) and GRACE Follow‐On (GRACE‐FO) Stokes coefficients reveal that barystatic sea level averaged over the whole global ocean was rising by 1.72 mm a−1 during the period April 2002 until August 2016. This rate refers to a truely global ocean averaging domain that includes all polar and semienclosed seas. The result corresponds to 2.02 mm a−1 mean barystatic sea level rise in the open ocean with a 1,000 km coastal buffer zone as obtained from a direct spatial integration of monthly GRACE data. The bias of +0.3 mm a−1 is caused by below‐average barystatic sea level rise in close proximity to coastal mass losses induced by the smaller gravitational attraction of the remaining continental ice and water masses. Alternative spherical harmonics solutions from CSR, JPL, and TU Graz reveal open‐ocean rates between 1.94 and 2.08 mm a−1, thereby demonstrating that systematic differences among the processing centers are much reduced in the latest release. We introduce in this paper a new method to approximate spatial leakage from the differences of two differently filtered global gravity fields. A globally constant and time‐invariant scale factor required to obtain full leakage from those filter differences is found to be 3.9 for GFZ RL06 when filtered with DDK3, and lies between 3.9 and 4.4 for other processing centers. Spatial leakage is estimated for every month in terms of global grids, thereby providing also valuable information of intrabasin leakage that is potentially relevant for hydrologic and hydrometeorological applications.

Identifying opportunities for local assisted expansion of coastal upland vegetation in an urban estuary

Resilience planning requires an understanding of the potential impact of accelerated sea level rise on the narrow coastal habitats between the sea and the built environment in urban estuaries. Preliminary work suggests that facilitating expansion of coastal upland vegetation (grasslands and maritime shrubland/successional maritime forest) may improve resilience. We created a GIS model for Jamaica Bay, New York to identify areas of inland salt marsh migration induced by sea level rise and map potential locations for expansion of coastal upland vegetation through plantings of local provenance given land use, soil type, and adjacency to predicted future salt marshes. We predicted that regularly flooded salt marshes (low marsh) will comprise the large majority of salt marsh area (89% up from 68% currently) in the coming century due to daily tides covering areas currently categorized as irregularly flooded salt marsh (high marsh), brackish marsh and coastal upland vegetation. Considering land use, 16% of the area suitable for coastal upland vegetation within the coastal buffer zone could be considered possible sites for local assisted coastal upland vegetation expansion with about a fifth of those areas adjacent to predicted new sea level rise induced inland salt marsh areas. Parks and recreational facilities (43%) and open space (32%) were the dominant land uses available for local assisted coastal upland vegetation expansion adjacent to predicted new sea level rise induced inland salt marsh areas. Potential sites for local assisted coastal upland vegetation expansion were considerably more numerous on sandy soils than on loamy sand soils. Maintained lawn and shrubs and the borders of roads and railroads provided available space in areas disjunct from the predicted new salt marsh areas. Our study of opportunities for local assisted expansion of coastal upland vegetation fills a gap within existing models and informs land managers of predicted future inland salt marsh migration locations, regions of existing vegetation to support, and areas where restoration plantings may help sustain coastal upland vegetative communities and their many ecological services.

Predicting the impact of sea-level rise on intertidal rocky shores with remote sensing

Sea-level rise is an inevitable consequence of climate change and threatens coastal ecosystems, particularly intertidal habitats that are constrained by landward development. Intertidal habitats support significant biodiversity, but also provide natural buffers from climate-threats such as increased storm events. Predicting the effects of climate scenarios on coastal ecosystems is important for understanding both the degree of habitat loss for associated ecological communities and the risk of the loss of coastal buffer zones. We take a novel approach by combining remote sensing with the IUCN Red List of Ecosystem criteria to assess this impact. We quantified the extent of horizontal intertidal rocky shores along ~200 km of coastline in Eastern Australia using GIS and remote-sensing (LiDAR) and used this information to predict changes in extent under four different climate change driven sea-level rise scenarios. We then applied the IUCN Red List of Ecosystems Criterion C2 (habitat degradation over the next 50 years based on change in an abiotic variable) to estimate the status of this ecosystem using the Hawkesbury Shelf Marine Bioregion as a test coastline. We also used four individual rocky shores as case studies to investigate the role of local topography in determining the severity of sea-level rise impacts. We found that, if the habitat loss within the study area is representative of the entire bioregion, the IUCN status of this ecosystem is ‘near threatened’, assuming that an assessment of the other criteria would return lower categories of risk. There was, however, high spatial variability in this effect. Rocky shores with gentle slopes had the highest projected losses of area whereas rocky shores expanding above the current intertidal range were less affected. Among the sites surveyed in detail, the ecosystem status ranged from ‘least concern’ to ‘vulnerable’, but reached ‘endangered’ under upper estimates of the most severe scenario. Our results have important implications for conservation management, highlighting a new link between remote sensing and the IUCN Red List of Ecosystem criteria that can be applied worldwide to assess ecosystem risk to sea-level rise.

Movements and habitat use of loons for assessment of conservation buffer zones in the Arctic Coastal Plain of northern Alaska

Oil and gas development in the Arctic Coastal Plain, Alaska, may pose threats to wildlife. Management guidelines within the National Petroleum Reserve-Alaska dictate buffer zones for coastal wildlife habitat and for breeding and foraging sites of yellow-billed loons (YBLOs; Gavia adamsii), a species of conservation concern. However, few data exist to assess the value of these buffer zones for YBLOs or for sympatrically breeding red-throated loons (RTLOs; G. stellata) and Pacific loons (PALOs; G. pacifica). We evaluated movements of these loons on the Arctic Coastal Plain to understand: 1) seasonal timing; 2) marine habitat use; and 3) spatial characteristics of breeding home ranges. We then used those findings to evaluate current management strategies in the context of loon biology. Compared to RTLOs and PALOs, YBLOs nested on larger lakes, stayed on them longer, had larger home ranges, but less frequently used the marine environment in summer. During autumn, YBLOs and PALOs were located farther from shore than during spring or summer, whereas RTLOs used the marine environment similarly during all three seasons. Management buffers established for YBLO nesting areas corresponded well with nest site space use of all three species, suggesting cross-taxa applicability of current management guidelines for nesting habitat. However, the majority of loon locations on the Arctic Coastal Plain were outside of coastal buffer zones established to protect fish and wildlife habitat within the National Petroleum Reserve-Alaska. These findings can inform assessment of conservation buffer zones to mitigate anthropogenic disturbance to loons in Alaska.