Shoreline Advancement Research Articles

Spatiotemporal analysis of shoreline change trends and adaptation in Bali Province, Indonesia

Shoreline change is a dynamic and complex phenomenon influenced by various natural and anthropogenic factors. Monitoring these changes is crucial for understanding coastal dynamics, managing resources, and mitigating the impacts of coastal erosion and accretion. Remote sensing plays a vital role in monitoring shoreline change. This technology has emerged as a powerful tool for accessing and monitoring shoreline changes due to its ability to capture large-scale spatial data over different periods. This study investigated the dynamic changes in shoreline position in Bali Province from 2016 to 2021 using high-resolution PlanetScope imagery data. Multitemporal shorelines were extracted using the Normalized Difference Water Index (NDWI) to delineate seawater from distinct land-cover types. The end point rate (EPR) model was then used to statistically quantify the shoreline change rates. The results revealed variations in the positions of the shorelines throughout the study, with rapid erosion emerging as a major concern in Bali Province, primarily driven by human activities and/or coastal hydrodynamics. During the study period, the shoreline in Bali Province decreased from 668.64 km to 662.59 km at an average rate of -1.21 m/yr due to continuous erosion, with the most significant retreat occurring at Klungkung Regency. On the other hand, human-caused shoreline advancement, such as land reclamation, harbor, and airport construction, has resulted in a net land increase of 1.25 km2. The protection strategies include structural interventions such as breakwaters and seawalls. The finding provides valuable information that will be helpful for coastal planning and management to reduce the loss of the economy and safeguard the future coastal environment in Bali’s coastal areas.

STUDY OF CROSS-SHORE PROFILES AT SOUTH COASTS OF THE CASPIAN SEA UNDER RAPID CHANGES IN WATER LEVEL

Coastal zone management needs the prediction of the changes in shoreline and coastal profiles, where the fluctuation of sea water level plays an essential role. Climate change and human activities have accelerated the fluctuation/falling of water levels in lakes and enclosed water basins. Using satellite images and cross-shore beach profiles at twelve monitoring stations along the southern coasts of the Caspian Sea, the effect of the rapid fall of water level on the nearshore morphology is studied in this research. Radiometric and atmospheric corrections are made on satellite images, and the NDWI index is used to increase the accuracy of the shoreline extraction. Comparing the accuracy of different methods, it is concluded that the Hands (1984) formula relatively better predicts the shoreline advancement rate due to lowering water level.

Shoreline change detection along North Sebou–Moulay Bousselham, based on remote sensing analysis

Sustainable management of the shoreline is crucial. Shoreline mapping is very essential to investigate the impact of the dynamic nature of the coastal area over a certain period. Coastal zone at the north Sebou estuary experience some issues as shoreline retreats as well as shoreline advancement in some locations. Shoreline mapping along the northern area of Sebou estuary was implemented by applying remote sensing technology to detect and analyze shoreline changes.Multi-temporal satellite images with different periods during the last 37 years (1984–2021) were used to detect changes as well as analyze shoreline change rates. Landsat images (Landsat 5–TM, Thematic Mapper TM, Landsat7 ETM+, Landsat 8 OLI_TIRS) were corrected from geometric and radiometric perspectives, then classified by assigning six different classes for analyzing the evolution of the coastal zone from 1984 to 2021. To detect changes in both land use and land cover, the Support Vector Machine algorithm supervised classification was executed to classify the images. As a powerful statistical analysis tool, DSAS was used to assess the rate of shoreline change by EPR technique and to anticipate the required coastal protection measures along the coastline.The classification results show that agricultural land, bare land, and sand-dune beaches have decreased by −8.26%, −5.92%, and −4.53% respectively. On the other hand, statistical analysis of DSAS shows that the northern area of Sebou estuary experienced an average accretion rate of (+0.96 m/yr) while erosion rates achieved an average of (−1.04 m/yr). A drastic erosion was noticeable at the right side of the estuary with (−3.1 m/yr). The decision matrix by EPR method has been developed. It illustrates the evolution, risk level, and proposed decision at each sector along the shorelines during the preceding three decades. The final goal of this study is to support decision-makers in implementing preventive management techniques in the most vulnerable locations.

Asymmetry between Accretional Advance and Erosional Retreat of Shoreline Position in On-offshore Direction

Yoo, H.J.; Kim, H.; Lee, J.L., and Park, J.Y., 2021. Asymmetry between accretional advance and erosional retreat of shoreline position in on-offshore direction. In: Lee, J.L.; Suh, K.-S.; Lee, B.; Shin, S., and Lee, J. (eds.), Crisis and Integrated Management for Coastal and Marine Safety. Journal of Coastal Research, Special Issue No. 114, pp. 6–10. Coconut Creek (Florida), ISSN 0749-0208. Episodic shoreline retreat often slowed recovery in low frequency periods (weeks or months). The asymmetry between wave energy rise and collapse is closely related to the asymmetry of shoreline advancement and retreat, but the latter is more pronounced due to the different profile adjustment processes. Long-term wave time series data and shoreline time series data were analyzed at Won-pyeong beach located on the east coast of Korea. When waves such as storms come into the beach, the shoreline quickly retreated, and in relatively quiet times, the beach slowly recovered to it's original position. Also, the asymmetry of the shoreline position with respect to time is stronger than that of the wave height. A methodology is proposed here, and the envelope rope curve can be used to predict profile and average shoreline changes in the reference section for erosion steps such as storms.The proposed equation was in good agreement for shoreline asymmetry position, and is satisfactory. Empirical formular are slightly different in the relatively calm period, this is an artificial change formed by external pressure conditions such as artificial nourishment. Several variables were used as correction factors. It`s important for future research to propose standardized correction factors and ranges by applying them at various sites.

A multidisciplinary approach to study slope instability in the Alboran Sea shoreline: Study of the Tamegaret deep-seated slow-moving landslide in Northern Morocco

Coastal landslides cause great economic damage to human installations along the Mediterranean shoreline. In the Alboran Sea, this phenomenon is very common and causes many problems for residential resorts and road infrastructures in coastal areas. In the last two decades, such slope instability processes were the subject of many studies, which employed multidisciplinary approaches to understand their underlying mechanisms and surficial kinematics in Southern Spain and elsewhere in the Mediterranean. However, advanced and new investigation methods and techniques used in these studies have never been performed in Northern Morocco despite the geomorphological, geological and climatic resemblance between the two regions. In this paper we analyze the mechanisms and processes controlling the Tamegaret slow-moving deep-seated landslide (Northern Morocco) in order to bridge this knowledge gap and to understand landslide slope dynamics on their regional context. To do so, Electrical resistivity Tomography, field investigations and multi-temporal Synthetic Aperture Radar Interferometry (InSAR) were performed to characterize slope instability processes at the study area. The interpretation of Historic aerial photographs and UAV surveys was also conducted to study the major redistribution of mass caused by recent road widening work at the landslide headscarp. Results show that the Tamegaret landslide owes its existence to deep creep processes controlled by a rock flow type gravitational deformation. Extensional tectonic structures and marine erosion processes that eliminate landslide deposits from the foot area constitute the most relevant control factors of this dynamic. InSAR results show that this deep-seated landslide is currently (2017–2019) characterized by very slow displacement rates (2–3 cm/year maximum). Yet, the substantial deformation observed both in the field and on aerial/satellite photographs suggests that the acceleration occurred during the road-widening work which caused major changes to the natural topography in the period (2009–2012). This deformation phase was manifested by local shoreline advancement at the landslide foot area. Such results show that studying historic shoreline variations can be an effective low-cost time-saving tool allowing the reconstruction of active landslide kinematics in coastal areas. On a regional scale, findings of this study highlight the resemblance between the coasts of Southern Spain and Northern Morocco in terms of (i) the geomorphological processes controlling the coastal slope dynamics at the region; (ii) the displacement rates measured in Tamegaret compared to other unstable slopes in the Northern shore of the Alboran Sea and (iii) the bad-engineering on old dormant landslides which compromises their stability. Therefore, we suggest limiting construction work on coastal hillslopes of Northern Morocco in order to prevent bad construction practices from causing economic losses in the Southern shoreline of the Alboran Sea as well.

Spatio-Temporal Analysis of Shoreline Movements along the Coastal Stretch from Bortianor to Winneba, Ghana

Shoreline movement is largely dependent on the extent of erosion and accretion, thus making it one of the most dynamic geomorphic phenomena along the coast. The study sought to assess the spatio-temporal dynamics of shoreline movements along the coastal stretch between Bortianor in the Greater Accra Region and Winneba in the Central Region of Ghana from 2000 to 2020. The study used shoreline data mapped from field-based high resolution aerial imagery and Landsat 7 and 8 images. Digital Shoreline Analysis System (DSAS) software 5 was used for the data processing and analysis, with reference to Shoreline Change Envelope, Net Shoreline Movement, End Point Rate, Linear Regression Rate and Weighted Linear Regression. It was observed that the entire shoreline under study generally experienced a continuous retreat than advancement due to the moderate to very high accretion. This notwithstanding, very high erosion was observed on the eastern side of the coast in Fete, leading to an advancement of the shoreline. The study recommends constant monitoring of the coastline by researchers and relevant stakeholders and also the need to put in place protective mechanisms such as sea defenses by the Ministry of Water Resources, Works and Housing to avoid the worse scenarios being experienced in other parts of the Ghanaian coastline. Keywords: shoreline movements, accretion, erosion, shoreline retreat, shoreline advancement DOI: 10.7176/JEES/11-1-04 Publication date: January 31 st 2021

STUDY OF RAPID SEDIMENTATION AT PARESAR INTAKE BASIN, CASPIAN SEA, DUE TO LARGE WRACK PARTICLES AND WIND-INDUCED CURRENTS

The rapid sedimentation at the entrance of Paresar intake basin is studied, in which unnatural wrack accumulation at the coast, combined with the existing sand, resulted in a major increase in the actual Longshore Sediment Transport (LST) rate. Considering the volume of updrift fillet at the northwest of main breakwater and the estimated LST rate, the advancement of updrift shoreline was highly unexpected. Sands and vegetative wracks were observed only 3 years after constructing the rubble mound breakwaters, resulting in water depth decrease at the entrance. Employing field measurements and numerical modeling, it is revealed that general wind-induced currents in Caspian Sea, which were ignored in the design, have a small effect on increasing LST rate. The unusual sedimentation can be mainly related to the high percentage of wrack particles at updrift coast.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/UNNnjDHL41k

Decadal effects of solid industrial wastes on the coastal environment: Gulf of Gabes (Tunisia, Southern Mediterranean Sea) as an example

The present work examines the different types of solid effluents dumped in the coastal environment from Gabes phosphate fertilizer plants, describes their coastal repartition and assesses their long-term environmental impacts. Scanning Electron Microscopy analysis of collected beach sediment samples showed that these wastes consist of phosphogypsum, fluorapatite (phosphate ore grains), smokey quartz, calcite, fluorite, calcite-Mg, apatite, pyrite, albite, sphalerite-Cd-U, fluorosilicates, sulfur dross and spent catalysts. Using fluorapatite as a mineralogical marker of the coastal spatial distribution of industrial wastes, solid effluents were found to carry bottom and/or suspended loads with a coastal transport limited at Essorrag Wadi, ∼10 km south from the industrial emissary. Phosphogypsum which is the main solid effluent was found to be completely dissolved in the seawater. The main decadal consequences of solid effluents on the coast were found to be the following: local disappearance of Posidonia oceanica seagrass, formation of an azoic benthic zone between Gabes and Ghannouche ports, gradual fattening of the beach, shoreline advancement, formation of a belt of coastal dunes, mouth clogging of coastal streams and formation of coastal lakes.

Salt and Wetland: Traditional Development Landscape, Land Use Changes and Environmental Adaptation on the Central Jiangsu Coast, China, 1450–1900

China’s coastal wetlands are subjected to increasing pressure in terms of the sustainability of the economic and social development, due to the rapid industrialization and urbanization over the last 30 years; the protection and sustainable use of wetland resource requires local knowledge of traditional development model, management policy and historical landscape change. However, there is a lack of the relevant research of traditional wetland utilization and environmental adaptation practice for China’s coast. Using the various data sets of the central Jiangsu coast, we reconstruct traditional development patterns of wetland and environmental adaptation process, based on a historical approach. The results show that, in this dynamic tidal flat wetland, with continued shoreline advancement, traditional salt-making activity in this region formed a low-density distribution and labor-intensive pattern, which had a remarkable adaptive change of production pattern from centralization to dispersion; this unique cultural ecological landscape was the result of the combined action between wetland evolution and monopolistic land use policies. This study reveals a representative cultural ecological landscape of coastal wetland development in China; an improved understanding of human-coast interaction and local knowledge is beneficial to the management of wetland resource uses, enhancing the value of ecosystem services provided by coastal wetlands.

WAVE ATTENUATION AND SEDIMENT TRANSPORT MONITORING OF LIVING SHORELINES IN THE DELAWARE BAY, U.S.

Living shorelines are considered a more natural approach to shoreline stabilization for low-energy coastlines in contrast to traditional “hard” shoreline armoring methods (i.e. bulkheads). Living shorelines often vary by design and materials, which are optimized for site-specific coastal and environmental conditions, such as wave climate, tidal range, sunlight exposure, etc.; however, the core benefits of all engineered living shorelines are typically the same: reduce shoreline erosion; enhance marine, intertidal, or backshore habitat; and increase resiliency to storm surge and/or sea level rise. While the general benefits of living shorelines are well known, project-specific technical data (i.e. percent of wave energy attenuation, shoreline advancement rates) documenting the effectiveness of living shorelines is more sparse. Moreover, monitoring equipment and analysis techniques required to capture the fine-detailed technical data can prove to be cost and/or labor intensive.

Recent Niger Delta shoreline response to Niger River hydrology: Conflict between forces of Nature and Humans

The Niger River Delta is a prolific hydrocarbon province and a mega-delta of economic and environmental relevance. To understand patterns of its recent shoreline evolution (1923–2013) in response to the Niger River hydrology, and establish the role played by forces of Nature and Human, available topographic and satellite remote sensing data, combined with hydro-climatic (rainfall and runoff) data were analyzed.Results indicate that the entire delta coastline dramatically receded: 82% of the >400 km-long coast retreated, during the period 1950–1987; and 69% between 2007 and 2012. Prior to 1950, there was a continuation of seaward advancement along 53–74% of the delta coast. The 1950–1987 shoreline recession coincided with occurrences of two major events in the Niger River basin; these are downward trends in hydro-climatic conditions (the great droughts of the 1970s-1980s), and dam construction on the Lower Niger River at Kainji (1964–1968). The 2007–2012 event corresponded with the extensive channel dredging during 2009–2012 in the Lower Niger River from the coastal town of Warri in the south to Baro in the north. Remarkably, the largest net shoreline advancement recorded in 74% of the entire delta area occurred within a year (2012–2013), which we link to increased sediment supply to the coast caused by the ‘2012’ floods, adjudged the worst floods in the entire Niger River Basin in the last few decades. With both anthropogenic and environmental factors inducing delta evolution, only innovative river and coastal management can determine the fortune of the future coastal development of the Niger Delta.

Shoreline changes at selected stretches on the Thiruvananthapuram-Kochi coast, southwest India

Information on shoreline changes is important for the planning of coastal protection works and development of infrastructure facilities in the coastal belt. The Thiruvananthapuram–Kochi sandy coastline in Kerala (India) is prone to severe changes in geomorphology. Continuous monthly data on shoreline positions with respect to the reference stations have been available for this study from 1989 to 2003; these data are analyzed for the seasonal, short- and medium-term changes. Results revealed that the magnitude of fluctuation of the shoreline positions varies with respect to the season and stretch. Seasonal fluctuation is maximum during the southwest monsoon, followed by the non-monsoon season. Shoreline changes classified under erosion, accretion, fluctuation, and stable condition are observed at different stations. During the period, maximum and minimum changes due to erosion occurred at Ambalapuzha and Eravipuram, respectively. Annual maximum fluctuation at any station is found to be 0.5–0.9 times that of the maximum fluctuation observed at that station for the entire period. Stretches with shore protection structures behaved differently, exhibiting continuous recession, tendency to arrest recession, fluctuation and advancement of shoreline. The changing trend – maximum and minimum distance to the shoreline – observed at Arattupuzha is unique when compared to that at other study reaches.

Integrating millennial and interdecadal shoreline changes: Morpho-sedimentary investigation of two prograded barriers in southeastern Australia

Prograded barriers are distinctive coastal landforms preserving the position of past shorelines as low relief, shore-parallel ridges composed of beach sediments and commonly adorned with variable amounts of dune sand. Prograded barriers have been valued as coastal archives which contain palaeoenvironmental information, however integrating the millennial timescale geological history of barriers with observed inter-decadal modern beach processes has proved difficult. Technologies such as airborne LiDAR, ground penetrating radar (GPR) and optically stimulated luminescence dating (OSL) were utilised at Boydtown and Wonboyn, in southeastern Australia, and combined with previously reported radiocarbon dates and offshore seismic and sedimentological data to reconstruct the morpho-sedimentary history of prograded barrier systems. These technologies enabled reconstruction of geological timescale processes integrated with an inter-decadal model of ridge formation explaining the GPR-imaged subsurface character of the barriers. Both the Boydtown and Wonboyn barriers began prograding ~7500–8000years ago when sea level attained at or near present height along this coastline and continued prograding until the present-day with an initially slower rate of shoreline advancement. Sources of sediment for progradation appear to be the inner shelf and shoreface with a large shelf sand body likely contributing to progradation at Wonboyn. The Towamba River seems to have delivered sediment to Twofold Bay during flood events after transitioning to a mature estuarine system sometime after ~4000cal. yr BP. Some of this material appears to have been reworked onto the Boydtown barrier, increasing the rate of progradation in the seaward 50% of the barrier deposited over the past ~1500years. The GPR imaged beachfaces are shown to have similar geometry to beach profiles following recent storm events and a model of ridge formation involving cut and fill of the beachface, and dune building in the backshore, explains the character of the preserved beachface record and the morphology of the ridges. This model is applicable to future management of individual beaches where such beaches are subject to ongoing cut and fill, dune building processes and inherited sediment budget conditions.

Effects of Shoreline Dynamics on Saltmarsh Vegetation.

We evaluated the impact of shoreline dynamics on fringing vegetation density at mid- and low-marsh elevations at a high-energy site in the northern Gulf of Mexico. Particularly, we selected eight unprotected shoreline stretches (75 m each) at a historically eroding site and measured their inter-annual lateral movement rate using the DSAS method for three consecutive years. We observed high inter-annual variability of shoreline movement within the selected stretches. Specifically, shorelines retrograded (eroded) in year 1 and year 3, whereas, in year 2, shorelines advanced seaward. Despite shoreline advancement in year 2, an overall net erosion was recorded during the survey period. Additionally, vegetation density generally declined at both elevations during the survey period; however, probably due to their immediate proximity with lateral erosion agents (e.g., waves, currents), marsh grasses at low-elevation exhibited abrupt reduction in density, more so than grasses at mid elevation. Finally, contrary to our hypothesis, despite shoreline advancement, vegetation density did not increase correspondingly in year 2 probably due to a lag in response from biota. More studies in other coastal systems may advance our knowledge of marsh edge systems; however, we consider our results could be beneficial to resource managers in preparing protection plans for coastal wetlands against chronic stressors such as lateral erosion.

Reprint of Evolution of an anthropic source to sink system: Wabush lake

Wabush Lake is one of the few very well-constrained source-to-sink sedimentary systems in the world that exhibits near-continuous turbidity currents. In this system, approximately 20million tons of mine tailings are delivered each year to a 40km2 lake. Multibeam bathymetric surveys of this lake were carried out between 1999 and 2011. In addition, a program of extensive sampling and seismic surveys, an airborne LiDAR survey and a photogrammetric survey were carried out during this period. The objective of this study was to determine the evolution through time of this anthropic source-to-sink system, from the point where sediments exit the slurry pipelines at the head of the system to the distal end and bottom of the Lake. The total volume of the Lake is around 1×109m3.Analysis of subaerial and subaqueous datasets allows the evaluation of disposal strategies on the delta topset and on tailings accumulation. Disposal strategies influence the dynamics of the channels on the topset, thus in turn affecting the accumulation of tailings throughout the lake, as well as the shoreline advancement rate. Subaqueous erosional channels present on the bed of the Lake influence the depositional pattern of tailings as well as their granulometric distribution. These erosional channels are created by the shoreward migration of knickpoints. In some places, this migration can be documented over multiple surveys.Finally, sequential analysis of the 1999, 2004, 2006, 2008 and 2011 surveys has allowed detailed documentation of the infilling of the Lake, including the migration of sediment depocenters, the mechanism of emplacement and the progressive infilling of a series of minibasins.

Evolution of an anthropic source-to-sink system: Wabush Lake

Wabush Lake is one of the few very well-constrained source-to-sink sedimentary systems in the world that exhibits near-continuous turbidity currents. In this system, approximately 20million tons of mine tailings are delivered each year to a 40km2 lake. Multibeam bathymetric surveys of this lake were carried out between 1999 and 2011. In addition, a program of extensive sampling and seismic surveys, an airborne LiDAR survey and a photogrammetric survey were carried out during this period. The objective of this study was to determine the evolution through time of this anthropic source-to-sink system, from the point where sediments exit the slurry pipelines at the head of the system to the distal end and bottom of the Lake. The total volume of the Lake is around 1×109m3.Analysis of subaerial and subaqueous datasets allows the evaluation of disposal strategies on the delta topset and on tailings accumulation. Disposal strategies influence the dynamics of the channels on the topset, thus in turn affecting the accumulation of tailings throughout the lake, as well as the shoreline advancement rate. Subaqueous erosional channels present on the bed of the Lake influence the depositional pattern of tailings as well as their granulometric distribution. These erosional channels are created by the shoreward migration of knickpoints. In some places, this migration can be documented over multiple surveys.Finally, sequential analysis of the 1999, 2004, 2006, 2008 and 2011 surveys has allowed detailed documentation of the infilling of the Lake, including the migration of sediment depocenters, the mechanism of emplacement and the progressive infilling of a series of minibasins.

MODELLING OF SEDIMENT TRANSPORT IN BERIS FISHERY PORT

In this paper, the large amount of sedimentation and the resultant shoreline advancements at the breakwaters of Beris Fishery Port are studied. A series of numerical modeling of waves, sediment transport, and shoreline changes were conducted to predict the complicated equilibrium shoreline. The outputs show that the nearshore directions of wave components are not perpendicular to the coast which reveals the existence of longshore currents and consequently sediment transport along the bay. Considering the dynamic equilibrium condition of the bay, the effect of the existing sediment resources in the studied area is also investigated. The study also shows that in spite of the change of the diffraction point of Beris Bay after the construction of the fishery port, the bay is approaching its dynamic equilibrium condition, and the shoreline advancement behind secondary breakwater will stop before blocking the entrance of the port. The probable solutions to overcome the sedimentation problem at the main breakwater are also discussed.

Shoreline evolution due to construction of rubble mound jetties at Munambam inlet in Ernakulam–Trichur district of the state of Kerala in the Indian peninsula

Munambam inlet is in the West Coast of India falling in Ernakulam–Trichur districts of Kerala. This is the point where the north branch of Periyar river after joining Chalakudi and Pullut rivers meets the Arabian Sea. Due to the littoral drift from the north direction, a sand spit had formed at the mouth which caused frequent capsizing of boats. In order to arrive at a permanent problem, two breakwaters of length 360 m and 625 m had been constructed in the year 2000. After the construction of the breakwaters, the sand spit disappeared and there was considerable improvement in the bathymetry at the initial periods but the problem recurred. This paper highlights the details of the shoreline evolution from 1975 to 2012 derived from the actual field data and MIKE 21. The results indicate that the advancement of shoreline on either sides of the inlet is a peculiar phenomenon unlike erosion on one side and accretion on the other. Short term solutions for the management of the recurring problems are suggested in this paper. Long term solutions to the problem are also suggested, such as calling for the attention of the state and local government and research organizations.

Sedimentary evidence of Late Holocene human activity in the Pearl River delta, China

AbstractThis study examines the sedimentary evidence of human activities during the last 4000 years in the Pearl River deltaic area. The analyses are focused on indentifying agricultural signatures present in the sedimentary record and establishing the timing of a change from a simple, rice‐based agriculture to a more advanced, diverse agriculture. The examination is based on modern sediment and plant samples and a sediment core collected from the deltaic area. The analyses include particle size and diatom analysis to determine the environmental conditions that were associated with the period of human activities. Organic carbon isotope ratios and major metal elements reveal an expansion in commercial crop production and metal smelting in the Pearl River delta area about 2000 years ago. The input of organic matter from introduced sugarcane, a C4 plant, elevates the bulk organic carbon isotope values in the estuarine sediments above that represented by other common agricultural crops in the study area, including rice, banana and lotus, which are all C3 plants. The increase in bulk organic isotopic value coincides with the rise in the concentration of copper, iron and lead in the sedimentary sequence, suggesting a wider use of metal tools. These results indicate that advanced agriculture started about 2000 years ago as an expansion in human population took place in the area. This record also provides sedimentary evidence that help ascertain the timing and type of human activities that are linked to subsequent land reclamation on the deltaic plain, resulting in rapid shoreline advancement in the last 2000 years. Copyright © 2010 John Wiley & Sons, Ltd.

Frequent Monitoring and Numerical Modeling of Shoreline Change based on Automated Image Recording System

A monitoring method is applied to Yokosuka Coast in Miyagi Prefecture for understanding short-term topography change induced by wave action. Using images from an automated digital camera installed on the coast, shoreline position is determined after correcting the influence of wave run-up and tidal variation. Observed shoreline on the southern coast shows temporal variation in response to wave motion, whereas in the northern part of the study area, shoreline advancement is predominantly observed due to consistent recovery of the river mouth sand bar. Furthermore, a simple numerical modeling based on linear response function is applied to the present data set to reproduce the measured short-term shoreline variation.