Coastal zones are dynamic interfaces responding to complex natural processes and anthropogenic pressures.Monitoring shoreline evolution is essential for sustainable coastal management,particularly given climate change...Coastal zones are dynamic interfaces responding to complex natural processes and anthropogenic pressures.Monitoring shoreline evolution is essential for sustainable coastal management,particularly given climate change,urban expansion,and sediment flux disruption.This study investigates shoreline changes along Morocco’s northern Atlantic coast from 1990 to 2023,an area of strategic economic importance and environmental vulnerability.Landsat satellite imagery and geospatial techniques,including the Digital Shoreline Analysis System(DSAS v5.1)and the Normalized Difference Water Index(NDWI),provided a high-resolution,diachronic assessment.Shoreline extraction and image enhancement were conducted with ENVI software,and change detection utilized Linear Regression Rate(LRR)and End Point Rate(EPR)indicators.Results revealed significant spatial variability:sectors like northern Moulay Bousselham and Chlihat showed pronounced accretion(+3.2 to+4.7 m/year),while areas such as Tahaddart and southern Mehdia experienced severe erosion(up to−3.4 m/year).The total net eroded area exceeds 58,000 m².Trends correlate strongly with hydrodynamic forces,upstream damming,sediment extraction,and extreme weather events,notably storms in 2014 and 2017.Findings align with studies highlighting compounded effects of sediment starvation and sea-level rise.By integrating remote sensing,time-series analysis,and uncertainty quantification,this research provides insights into the primary drivers of shoreline dynamics,emphasizing the urgent need for adaptive,evidence-based coastal management strategies,including regulation of sand mining,sediment buffer restoration,and soft-engineering solutions.展开更多
Numerical analysis was made for shoreline evolution in the vicinity ofcoastal structures, including spur dike, detached breakwaters. The nonlinear partial differentialequation was derived, and numerical solutions were...Numerical analysis was made for shoreline evolution in the vicinity ofcoastal structures, including spur dike, detached breakwaters. The nonlinear partial differentialequation was derived, and numerical solutions were obtained by the finite difference method. Thenumerical results show good agreement with previous analytical results.展开更多
This contribution focuses on a multidisciplinary research showing the geomorphological evolution and the beach sand composition of the Tyrrhenian shoreline between Capo Suvero promontory and Gizzeria Lido village(Cala...This contribution focuses on a multidisciplinary research showing the geomorphological evolution and the beach sand composition of the Tyrrhenian shoreline between Capo Suvero promontory and Gizzeria Lido village(Calabria,southern Italy). The aim of the geomorphological analysis was to reconstruct the evolutionary shoreline stages and the present-day sedimentary dynamics along approximately 6 km of coastline. The results show a general trend of beach nourishment during the period 1870–2019. In this period, the maximum shoreline accretion value was estimated equal to + 900 m with an average rate of + 6.5 m/yr. Moreover, although the general evolutionary trend is characterized by a remarkable accretion, the geomorphological analysis highlighted continuous modifications of the beaches including erosion processes. The continuous beach modifications occurred mainly between 1953 and1983 and were caused mainly by human activity in the coastal areas and inside the hydrographic basins. The beach sand composition allowed an assessment of the mainland petrological sedimentary province and its dispersal pattern of the present coastal dynamics. Petrographic analysis of beach sands identified a lithic metamorphi-clastic petrofacies, characterized by abundant fine-grained schists and phyllites sourced from the crystalline terrains of the Coastal Range front and carried by the Savuto River. The sand is also composed of a mineral assemblage comparable to that of the Amato River provenance. In terms of framework detrital constituents of QFL(quartz:feldspars:aphanitic lithic fragments) and of essential extraclasts, such as granitoid:sedimentary:metamorphic phaneritic rock fragments(Rg:Rs:Rm), sand maturity changes moderately from backshore to shoreface, suggesting that transport processes had a little effect on sand maturity. Moreover, the modal composition suggests that the Capo Suvero promontory does not obstruct longshore sand transport from the north. Indeed, sands displaced by currents driven by storm-wave activity bypass this rocky headland.展开更多
Research on the laws controlling the shoreline equilibrium shape has been one important topic of studying the evolvement and stabilization of sandy coasts. After a brief review of the progress on the equilibrium shape...Research on the laws controlling the shoreline equilibrium shape has been one important topic of studying the evolvement and stabilization of sandy coasts. After a brief review of the progress on the equilibrium shape laws research, five models are introduced in detail. Advantages and disadvantages of these models are then discussed, which leads to the conclusion that the empirical formula integrating with analysis of mechanism should be the future direction of study on the headland-bay equilibrium shape laws. Finally, the importance of the study on the equilibrium shape of headland-bay in China is also discussed.展开更多
Shoreline change analysis frequently begins with feature identification through visual interpretation(proxy-based shoreline)or the intersection of a specific tidal zone(datum-based shoreline).Using proxy-based shoreli...Shoreline change analysis frequently begins with feature identification through visual interpretation(proxy-based shoreline)or the intersection of a specific tidal zone(datum-based shoreline).Using proxy-based shoreline information,this study quantifies the distance between proxy-based and datum-based shoreline data,which is defined as the proxydatum bias.The study was conducted at meso-tidal beaches in Kuala Nerus,Terengganu,Malaysia,with morphodynamic responses to northeast and southwest monsoons.The high-water line(HWL)shoreline(proxy-based)was determined using ortho-rectified aerial images captured by an unmanned aerial vehicle(UAV).By contrast,the mean high-water(MHW)shoreline(datum-based)was determined using measured beach profiles adjusted with the Peninsular Malaysia Geodetic Vertical Datum(DTGSM).The theoretical proxy-datum bias was approximated using the best estimate(median)for the beach slope,wave height,and wave period from the estimated total water level(TWL)model.Based on the study,the recorded horizontal proxy-datum bias for the research area was up to 32 m.This study also discovered that the theoretical assumption of the proxy-datum bias based on the TWL model yields values comparable to those of the measurements,with a narrower distinction in bias for steeper beach slopes than the obtained results.The determined proxydatum bias value can benefit future shoreline change studies as it could be incorporated to either proxy-based shorelines by shifting the shoreline seaward or to datum-based shorelines by shifting the shoreline landward in order of the bias value.The seasonal monsoon’s effect on beach profiles should be considered when calculating bias values and conducting potential shoreline change rate studies.展开更多
文摘Coastal zones are dynamic interfaces responding to complex natural processes and anthropogenic pressures.Monitoring shoreline evolution is essential for sustainable coastal management,particularly given climate change,urban expansion,and sediment flux disruption.This study investigates shoreline changes along Morocco’s northern Atlantic coast from 1990 to 2023,an area of strategic economic importance and environmental vulnerability.Landsat satellite imagery and geospatial techniques,including the Digital Shoreline Analysis System(DSAS v5.1)and the Normalized Difference Water Index(NDWI),provided a high-resolution,diachronic assessment.Shoreline extraction and image enhancement were conducted with ENVI software,and change detection utilized Linear Regression Rate(LRR)and End Point Rate(EPR)indicators.Results revealed significant spatial variability:sectors like northern Moulay Bousselham and Chlihat showed pronounced accretion(+3.2 to+4.7 m/year),while areas such as Tahaddart and southern Mehdia experienced severe erosion(up to−3.4 m/year).The total net eroded area exceeds 58,000 m².Trends correlate strongly with hydrodynamic forces,upstream damming,sediment extraction,and extreme weather events,notably storms in 2014 and 2017.Findings align with studies highlighting compounded effects of sediment starvation and sea-level rise.By integrating remote sensing,time-series analysis,and uncertainty quantification,this research provides insights into the primary drivers of shoreline dynamics,emphasizing the urgent need for adaptive,evidence-based coastal management strategies,including regulation of sand mining,sediment buffer restoration,and soft-engineering solutions.
文摘Numerical analysis was made for shoreline evolution in the vicinity ofcoastal structures, including spur dike, detached breakwaters. The nonlinear partial differentialequation was derived, and numerical solutions were obtained by the finite difference method. Thenumerical results show good agreement with previous analytical results.
基金funded by MIUR (Ministero dell’Istruzione, dell’Universitàe della Ricerca),ex 60% fund (2019 year) to Fabio Ietto。
文摘This contribution focuses on a multidisciplinary research showing the geomorphological evolution and the beach sand composition of the Tyrrhenian shoreline between Capo Suvero promontory and Gizzeria Lido village(Calabria,southern Italy). The aim of the geomorphological analysis was to reconstruct the evolutionary shoreline stages and the present-day sedimentary dynamics along approximately 6 km of coastline. The results show a general trend of beach nourishment during the period 1870–2019. In this period, the maximum shoreline accretion value was estimated equal to + 900 m with an average rate of + 6.5 m/yr. Moreover, although the general evolutionary trend is characterized by a remarkable accretion, the geomorphological analysis highlighted continuous modifications of the beaches including erosion processes. The continuous beach modifications occurred mainly between 1953 and1983 and were caused mainly by human activity in the coastal areas and inside the hydrographic basins. The beach sand composition allowed an assessment of the mainland petrological sedimentary province and its dispersal pattern of the present coastal dynamics. Petrographic analysis of beach sands identified a lithic metamorphi-clastic petrofacies, characterized by abundant fine-grained schists and phyllites sourced from the crystalline terrains of the Coastal Range front and carried by the Savuto River. The sand is also composed of a mineral assemblage comparable to that of the Amato River provenance. In terms of framework detrital constituents of QFL(quartz:feldspars:aphanitic lithic fragments) and of essential extraclasts, such as granitoid:sedimentary:metamorphic phaneritic rock fragments(Rg:Rs:Rm), sand maturity changes moderately from backshore to shoreface, suggesting that transport processes had a little effect on sand maturity. Moreover, the modal composition suggests that the Capo Suvero promontory does not obstruct longshore sand transport from the north. Indeed, sands displaced by currents driven by storm-wave activity bypass this rocky headland.
基金the National Natural Science Foundation of China under the contract No. 40576041.
文摘Research on the laws controlling the shoreline equilibrium shape has been one important topic of studying the evolvement and stabilization of sandy coasts. After a brief review of the progress on the equilibrium shape laws research, five models are introduced in detail. Advantages and disadvantages of these models are then discussed, which leads to the conclusion that the empirical formula integrating with analysis of mechanism should be the future direction of study on the headland-bay equilibrium shape laws. Finally, the importance of the study on the equilibrium shape of headland-bay in China is also discussed.
基金Supported by the Internal Grant of Universiti Malaysia Terengganu under the Translational Research Grant No.Vot 53464.
文摘Shoreline change analysis frequently begins with feature identification through visual interpretation(proxy-based shoreline)or the intersection of a specific tidal zone(datum-based shoreline).Using proxy-based shoreline information,this study quantifies the distance between proxy-based and datum-based shoreline data,which is defined as the proxydatum bias.The study was conducted at meso-tidal beaches in Kuala Nerus,Terengganu,Malaysia,with morphodynamic responses to northeast and southwest monsoons.The high-water line(HWL)shoreline(proxy-based)was determined using ortho-rectified aerial images captured by an unmanned aerial vehicle(UAV).By contrast,the mean high-water(MHW)shoreline(datum-based)was determined using measured beach profiles adjusted with the Peninsular Malaysia Geodetic Vertical Datum(DTGSM).The theoretical proxy-datum bias was approximated using the best estimate(median)for the beach slope,wave height,and wave period from the estimated total water level(TWL)model.Based on the study,the recorded horizontal proxy-datum bias for the research area was up to 32 m.This study also discovered that the theoretical assumption of the proxy-datum bias based on the TWL model yields values comparable to those of the measurements,with a narrower distinction in bias for steeper beach slopes than the obtained results.The determined proxydatum bias value can benefit future shoreline change studies as it could be incorporated to either proxy-based shorelines by shifting the shoreline seaward or to datum-based shorelines by shifting the shoreline landward in order of the bias value.The seasonal monsoon’s effect on beach profiles should be considered when calculating bias values and conducting potential shoreline change rate studies.
