Severe Beach Erosion Research Articles

Climate change and Its Impact on coastal communities in india: A quantitative investigation

Climate change has become an international problem. It is having an impact on various facets of our lives. Particularly in coastal areas in India. The increasing sea levels, abnormal weather conditions, and severe weather occasions have become a substantial issue for those communities, representing a significant danger to their jobs and safety. India's extensive coastline spanning over 7,500 kilometersharbors a plethora of individuals who rely on the sea for their subsistence. However, the adverse effects of climate change have imperiled their existence, rendering them vulnerable to various perils. The repercussions of these cataclysmic changes have resulted in severe beach erosion, damage to infrastructure, and property loss, leaving the coastal communities in despair. To ameliorate this bleak predicament. This is imperative to explore sustainable solutions that can aid in mitigating the current situation. climate change has caused devastation to native habitats and wildlife. This influencing the economic situation and diversity of the region. how communities are adjusting to the transforming climate and what steps can be taken to lessen their susceptibility to the climate change effects.

Spatiotemporal Variability of Extreme Wave Storms in a Beach Tourism Destination Area

This study explores the spatiotemporal variability of extreme wave storms around the Canary archipelago, with special focus on the southern coastal flank of Tenerife island, a strategic beach tourism destination of large socioeconomic importance. To this end, experimental and simulated data of winds and waves are used to study the severity, seasonality, and directionality of wave storms with considerable potential to cause significant impact on beaches. Furthermore, tidal experimental records are employed to test the joint occurrence of wave storms and significantly high sea levels. Long-term statistical analysis of extreme wave storms at different locations reveals a complex spatial pattern of wave storminess around the islands and in the southern flank of Tenerife, due to the intricacy of the coastline geometry, the presence of deep channels between islands, the high altitude and complex topography of the islands, and the sheltering effects exerted by each island over the others, depending on the directionality of the incident wave fields. In particular, south of Tenerife, the energy content and directionality of wave storms show substantial spatial variability, while the timing of extreme wave storms throughout the year exhibits a marked seasonal character. A specific extreme storm is examined in detail, as an illustrative case study of severe beach erosion and infrastructure damage.

THE ROLE OF GEOTEXTILE TUBE AS LOW-CRESTED BREAKWATERS IN RESTORING SEVERE BEACH EROSION PROBLEM AT PEBUAHAN BEACH IN BALI ISLAND

Pebuahan Beach in Jembrana Regency, Bali has experienced severe beach erosion since the construction of the Nusantara Pengambengan fishing port, 10 km east of Pebuahan. Efforts to countermeasure the coastal problem has been carried out by many local residents, but failed due to strong longshore drift. Through a collaboration between the Research Center for Water Resources, the Bali Penida River Basin, and PT. Geotechnical Systemindo, the implementation of low-crested breakwaters (LCB) or PEGAR, made of Woven Geotextile Tubes was initiated. Four woven geotextile tubes C12.9 m with length varied from 20 m to 25 m were installed to form LCB with the length of 60 m, at distance to the coast of 50 m. The monitoring of shoreline changes was conducted over the 3 months after its installation, which shows the formation of a new shoreline with the amount of deposited sand of 185.8 m3. The breaking wave on LCB crest results in successfully controlling the longshore current, hence the longshore drift settles behind the LCB to form a new coastline. It is expected this field study can be treated as an additional input to improve LCB Guideline and to expand LCB effectiveness scope not only apply to shallow wave conditions and beaches such as on North coast of Java, but also can be applied more universally to a deeper coastal waters with high wave conditions.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/AFzvkvYY2Do

BEACH PROCESSES AND SHORE PROTECTION ALONG THE NORTHERN COLOMBIA COAST

The shoreline of northern Colombia is located in the tropical zone along the south coast of Caribbean Sea. Its coastal processes are strongly influenced by the northeast trade wind, which results in the dominating northeasterly approaching wave occurring over 95% of the time. This drives a persistent southwestward longshore sand transport. The state of the beach along the generally northeast-southwest trending northern Colombia coast is strongly influenced by this constant unidirectional longshore sediment transport. At locations where this westward longshore sand transport is interrupted, naturally or anthropogenically, beach accretion occurs along the updrift shoreline coupled with erosion at the downdrift side. Natural interruption of longshore transport can be caused by tidal inlets, protruding headland, shoreline orientation change, and nearshore bathymetry variations. Anthropogenic interruption of the longshore transport along the northern Colombia coast is mainly caused by the construction of groins, as well as harbors at some locations. Numerous groins were constructed due to their local success in creating beach accretion at the drift side. However, severe beach erosion occurs along the downdrift shoreline. Shoreline protection along the northern Colombia coast, and coasts in the tropical area in general, should carefully consider the persistent unidirectional longshore sand transport and should not be misguided by the local updrift accumulation as being a successful project.

Regional Scale Risk-Informed Land-Use Planning Using Probabilistic Coastline Recession Modelling and Economical Optimisation: East Coast of Sri Lanka

One of the measures that has been implemented widely to adapt to the effect of climate change in coastal zones is the implementation of set-back lines. The traditional approach of determining set-back lines is likely to be conservative, and thus pose unnecessary constraints on coastal zone development and fully utilising the potential of these high-return areas. In this study, we apply a newly developed risk-informed approach to determine the coastal set-back line at regional scale in a poor data environment. This approach aims to find the economic optimum by balancing the (potential) economic gain from investing in coastal zones and the risk of coastal retreat due to sea level rise and storm erosion. This application focusses on the east coast of Sri Lanka, which is experiencing rapid economic growth on one hand and severe beach erosion on the other hand. This area of Sri Lanka is a highly data-poor environment, and the data is mostly available from global databases and very limited measurement campaigns. Probabilistic estimates of coastline retreat are obtained from the application of Probabilistic Coastline Recession (PCR) framework. Economic data, such as the discount rate, rate of return of investment, cost of damage, etc., are collated from existing estimates/reports for the area. The main outcome of this study is a series of maps indicating the economically optimal set-back line (EOSL) for the ~200-km-long coastal region. The EOSL is established for the year 2025 to provide a stable basis for land-use planning decisions over the next two decades or so. The EOSLs thus determined range between 12 m and 175 m from the coastline. Sensitivity analyses show that strong variations in key economic parameters such as the discount rate have a disproportionately small impact on the EOSL.

Influence of age and sex on winter site fidelity of sanderlings Calidris alba.

Many migratory bird species show high levels of site fidelity to their wintering sites, which confers advantages due to prior knowledge, but may also limit the ability of the individual to move away from degrading sites or to detect alternative foraging opportunities. Winter site fidelity often varies among age groups, but sexual differences have seldom been recorded in birds. We studied a population of individually colour-marked sanderlings wintering in and around the Tejo estuary, a large estuarine wetland on the western coast of Portugal. For 160 individuals, sighted a total of 1,249 times between November 2009 and March 2013, we calculated the probability that they moved among five distinct wintering sites and how this probability is affected by distance between them. To compare site fidelity among age classes and sexes, as well as within the same winter and over multiple winters, we used a Site Fidelity Index (SFI). Birds were sexed using a discriminant function based on biometrics of a large set of molecularly sexed sanderlings (n = 990). The vast majority of birds were observed at one site only, and the probability of the few detected movements between sites was negatively correlated with the distance among each pair of sites. Hardly any movements were recorded over more than 15 km, suggesting small home ranges. SFI values indicated that juveniles were less site-faithful than adults which may reflect the accumulated knowledge and/or dominance of older animals. Among adults, females were significantly less site faithful than males. A sexual difference in winter site fidelity is unusual in shorebirds. SFI values show site-faithfulness is lower when multiple winters were considered, and most birds seem to chose a wintering site early in the season and use that site throughout the winter. Sanderlings show a very limited tendency to explore alternative wintering options, which might have implications for their survival when facing habitat change or loss (e.g., like severe beach erosion as can be the case at one of the study sites).

Morphological Change near Artificial Reefs as a Beach Erosion Countermeasure

ABSTRACT Kim, K.H.; Shim, K.T., and Shin, B.S., 2016. Morphological Change near the Artificial Reefs as a Beach Erosion Countermeasure. In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 403–407. Coconut Creek (Florida), ISSN 0749-0208. At the Namhangjin Coast on the eastern coast of South Korea, there are five artificial reefs constructed as a form of countermeasure to prevent beach erosion. Since the construction, severe beach erosion has not occurred, and due to the presence of the artificial reefs various sedimentation effects have taken place. However, inside the opening gaps between the artificial reefs, the occurrences of return flow and severe scouring have been observed. In this field investigation the effects of one of the six artificial reefs, installed particularly for abalone, seaweed and fish farming, have been reviewed. Furthermore, th...

Analysis of Coastal Erosion due to the 2011 Great East Japan Tsunami and its Recovery Using Ground Penetrating Radar Data

ABSTRACT Takamura, M.; Udo, K.; Sato, M., and Takahashi, K., 2016. Analysis of Coastal Erosion due to the 2011 Great East Japan Tsunami and Its Recovery Using Ground Penetrating Radar Data. In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 477–481. Coconut Creek (Florida), ISSN 0749-0208. The 2011 Great East Japan Tsunami caused severe beach erosion along the Pacific coast. Eroded beaches began to recover rapidly after the tsunami, but the rate of beach recovery declined recently. We conducted a ground-penetrating radar (GPR) and borehole survey at Yamamoto Beach, which was eroded by the 2011 tsunami, to understand the tsunami recovery process using a new method that combines GPR, satellite images or aerial photographs, and tidal data. We compared reflective surfaces with geological layers observed using the GPR and borehole survey, respectively, to...

The Influence of a Seawall on Postnourishment Evolution in a Sea-Breeze-Dominated Microtidal Beach

ABSTRACT Medellin, G.; Marino-Tapia, I., and Euan-Avila, J., 2015. The influence of a seawall on postnourishment evolution in a sea-breeze-dominated microtidal beach. The postnourishment beach evolution is evaluated on a sea-breeze-dominated microtidal beach in Yucatan (Mexico). The study area has experienced severe beach erosion due to both alongshore sediment-transport gradients during calm conditions and offshore sediment transport during extreme wave events. Therefore, a shoreline restoration program, including beach nourishment and the removal of groynes, was carried out in 2002. Bimonthly subaerial/intertidal beach profiles measured during 7 years (2002–09), in front of a seawall and at an adjacent beach (nonwalled), are employed to analyze the beach nourishment evolution. Empirical orthogonal function (EOF) analysis of the shoreline time series is performed using the data extracted from the 50 field surveys. The temporal evolution of the EOF analysis shows the following: (1) an abrupt increase in b...

Composite coastal protection methods used at Cijin Coast, Taiwan

Cijin Coast has suffered from severe beach erosion and a consequent coastline retreat. To analyze the trend of topographic evolution of Cijin Coast, bathymetric data from field investigation were used and both numerical simulation and physical modeling were implemented in the wave basin to obtain the corresponding parameters that replicate similar phenomena. To protect Cijin Coast, composite coastal protection methods, such as submerged detached breakwaters accompanied with artificial nourishments, were proposed. Parameters used in previous studies were employed to test the proposed protection methods, and the results showed that the methods were effective in preventing the consequent retreat of the coastline. Thus, field construction of the proposed methods was initiated and completed in August 2013. Recent aerial photographs showed that the beach erosion was eliminated, proving the validity of the composite methods.

Beach Profile Model with Size-Selective Sediment Transport. II: Numerical Modeling

AbstractBeach profile evolution is a dynamic phenomenon that often leads to threatening consequences such as severe beach erosion and shoreline retreat. A new comprehensive morphodynamic model is introduced in this study that includes representation of bedload and suspended size-selective sediment transport and cross-shore sediment grain-sorting models. The model is capable of simulating the changes in cross-shore bathymetry and sediment grain size composition observed under laboratory conditions for both erosive- and accretive-type equilibrium beach profiles. The new model is most advantageous for scenarios with poorly sorted sediments or sites with strong cross-shore variability in sediment grain sizes. Information on sediment size composition in the domain and its history is also provided by the new model, which can be useful for engineering, recreational, or biological considerations.

Changes in beach gravel lithology caused by anthropogenic activities along the southern coast of Lake Michigan, USA

The southern coast of Lake Michigan is the most urbanized and most densely populated area in the Great Lakes region. Development of steel mills, harbors, and municipalities in NW Indiana and in NE Illinois in the last century and a half altered the nearshore environment so much that native beach gravel (>8 mm) now exist only in the exhumed paleo-beach remnants from the Nipissing Phase (~4,500 years ago) of Lake Michigan. Native gravel, collected from paleo-beach remnants at Mount Baldy Dune and Beach House Blowout, contain predominantly beach shingle, very platy siltstones (71–78 %), with secondary crystalline pebbles (18 %) in the east, and carbonate pebbles (12 %) in the west. A large amount of anthropogenic fill (steel industry waste, waste from power generating plants, construction debris, railroad, and road fill) has been added since the late 1800s to fill Lake Michigan and expand industrial land. Four areas of major coastal structures—Michigan City Pier and Breakwater, Burns Harbor Pier and Breakwater, Gary Works Pier, and Indiana Harbor Peninsula—altered the natural littoral drift and created four independent sectors on Indiana’s coast—Northeastern, Eastern, Central, and Western—between which no natural transfers of coarse sediments occur. Downdrift from the coastal structures, severe beach erosion has prompted extensive beach nourishment with non-native sandy gravel. Four distinct populations of modern beach gravel now exist along Indiana’s coast of Lake Michigan: (1) native gravel with diluted beach nourishment influence, (2) native gravel with a minor industrial influence, (3) compact gravel of nourished origin, and (4) anthropogenic gravel of industrial origin. Native gravel with diluted nourishment influence is found in the western, downdrift areas of the Northeastern (from Long Beach to Washington Park Beach) and Eastern Sectors (from eastern Indiana Dunes State Park to western Dune Acres) and contains up to 40 % compact carbonate and crystalline pebbles in addition to native beach shingle. Native gravel with minor industrial influence is found in the Central Sector of Indiana’s coast (from central Ogden Dunes to Marquette Beach) and contains predominantly beach shingle, platy clastic lithology, but also up to 30 % of chert and other pebbles released by industry. Compact gravel of nourished origin contains 60–90 % of carbonate and crystalline pebbles, and is found in the eastern, updrift areas of the Northeastern (Michiana Beach and Duneland Beach) and Eastern Sectors (from Crescent Beach to the western Beverly Shores). Anthropogenic gravel of industrial origin contains 70–90 % compact chert and slag and is found in every beach of the Western Sector and in the westernmost beach of the Central Sector. Streams draining into southern Lake Michigan generally contain little coarse sediment except in their channels near the roads and railroads, where angular to subangular anthropogenic pebbles predominate (70–90 %). However, streams have very little influence on gravel lithology along the coast because they seldom discharge anthropogenic gravel into Lake Michigan. Recent changes in gravel lithology along the southern Lake Michigan coast may affect changes in nearshore benthic flora and fauna as well as algal and bacterial blooms during warm summer months.

Sea level rise along the East Asia and Chinese coasts and its role on the morphodynamic response of the Yangtze River Estuary

Coastal phenomena at river estuary areas will be affected by global climate change conditions. This paper reports on analysis of the sea level rise (SLR) from the last 50years of tide stations data along the East Asia and Chinese coasts and morphodynamic changes in the Yangtze River Estuary determined for four SLR rates. Long-term tide records of 58 stations from the Permanent Service for Mean Sea Level (PSMSL) database were analyzed to develop projected estimates of the SLR trends. The calculated average rate of SLR is 2.67mm/yr along the East Asia coasts, and 2.89mm/yr along the Chinese coasts, with a 5.44mm/yr estimate at the Yangtze Estuary, which is nearly three times the global average. Including the joint effects of the SLR and coastal land subsidence, the relative SLR will range from 1.5m to 2.7m at the Yangtze Estuary by the end of this century. Under the conditions of dry season water discharge, numerical simulation results show that the flood and ebb velocities would decrease for the SLR greater than 0.18m. The areas of influence will increase proportional to the scale of SLR, significantly changing deposition conditions in this river estuary. Simulation results indicate that more dramatic morphological changes occur in the estuary during the dry conditions as compared to wet conditions. During the wet seasons, significant topography changes occur only for the SLR greater than 0.59m, with an associated increase in the current velocities outside the river mouth. This may induce severe beach erosion problems, especially along the northern coasts of the Yangtze Estuary.

Environmental impacts and simultaneity of positive and negative storm surges on the coast of the Province of Buenos Aires, Argentina

The Argentine shore of the Rio de la Plata estuary and its southwards adjacent maritime front are normally affected by extratropical positive and negative storm surges that affect human activities seriously. Positive surges can raise the water level in the estuary by more than 3 m over the predicted tide; thus, flooding the coastal plain where over 13 million people live and causing extensive property damage. Sometimes, there has been loss of life too. Although less populated than the coastal plain, the maritime front has many important tourist resorts and also undergoes severe beach erosion processes and loss of property owing to positive surges. Negative surges are particularly troublesome in the Rio de la Plata because they critically affect navigation safety and drinking water supply by lowering the predicted water level in an amount that sometimes reached more than 4 m. A remarkable point is that the same storm event can simultaneously give rise to a positive surge on the maritime front and a negative one in the Rio de la Plata. The environmental impacts of positive storm surges are strongly aggravated by human intervention. At the same time, sea level rise due to global climatic change has also its influence.

茨城県阿字ヶ浦海岸における海浜変形の再現計算

Ajigaura Beach is one of the famous bathing beaches in Ibaraki Prefecture. In recent years, severe beach erosion has occurred. Even though beach nourishment has been carried out as a measure against beach erosion, wave run-up damage often occurred in the south part of the beach where the foreshore was narrowed. In this paper, topographic changes of the beach were investigated on the basis of the past aerial photographs and bathymetric survey data, and the numerical simulation using the BG model was carried out to reproduce the measured beach changes. The measured and calculated results were in good agreement.

SAND ACCUMULATION IN WAVE-SHELTER ZONE OF OHARAI PORT AND CHANGE IN GRAIN SIZE OF SEABED MATERIALS ON NEARBY COAST

Beach changes around Oharai Port facing the Pacific Ocean were investigated using bathymetric survey data collected over 25 years between 1979 and 2004. Between the south and offshore breakwaters of Oharai Port, 1.50×106 m3 of fine sand was deposited in this period, i.e., at an annual rate of 6.0×104 m3/yr, which was originally supplied from the Naka River 3 km north of the port. Also in the wave-shelter zone of the offshore breakwater south of the port, 7.0×106 m3 of fine sand was deposited between 1979 and 2004 at an annual rate of 2.8×105 m3/yr, which was transported by the northward longshore sand transport induced from outside to inside the wave-shelter zone of the offshore breakwater, resulting in severe beach erosion on the south coast outside the wave-shelter zone. Taking into consideration the fact that sand transport to the Kashimanada coast is now completely obstructed by the port breakwaters, sand bypassing and sand back passing to the coast from the sand deposition zone of Oharai Port are required.

TOURISTS’ PERCEPTIONS IN A CLIMATE OF CHANGE: Eroding Destinations

This research examines tourists’ perceptions of a coastal destination that has suffered severe beach erosion and is undergoing beach replenishment. Officials assume that tourist will inevitably react negatively to the transformed landscape; however, the findings indicate that tourists decode the site in polysemous ways. This study engages Lefebvre’s triadic model of social space to inform the discussion of the symbolic landscapes meanings constructed by producers and consumers. The key argument is that in the advent of global climate change, both the material and social elements have to be considered to devise long-term adaptation measures. The findings shed light on complexities involved in tourism destination’s adaptation to geomorphologic/climatic changes as well as contested meanings that emerge from the human-environment relationship.

Numerical Simulation of Rapid Erosion of Seisho Coast Triggered by Storm Waves during Typhoon 0709

On September 6, 2007, the Seisho Bypass extending along the Seisho coast was severely damaged over a length of 1.1 km owing to storm waves associated with Typhoon 0709, resulting in roads being closed to traffic for urgent repairs. During the typhoon, severe beach erosion occurred owing to both strong offshore sand transport and westward longshore sand transport by storm waves, and the foreshore was rapidly narrowed. However, the foreshore was recovered except the damaged area of the highway as a result of the effect of normal waves. These beach changes were predicted using the contour-line-change model incorporating Fukuhama et al.'s concept. The predicted results were in good agreement with the measured beach changes.

A 1500 yr record of North Atlantic storm activity based on optically dated relict beach scarps

Understanding of long-term dynamics of intense coastal storms is important for determining the frequency and impact of these events on sandy coasts. We use optically stimulated luminescence (OSL) dates on relict scarps within a prograded barrier sequence to reconstruct the chronology of large-magnitude erosional events in the western Gulf of Maine. OSL dates obtained on quartz-rich sediments immediately overlying relict scarps indicate severe beach erosion and retreat due to erosional events ca. 1550, 390, 290, and 150 cal yr B.P. Our data provide new evidence of increased storm activity (most likely frequency and/or intensity of extratropical storms) during the past 500 yr, which was preceded by a relatively calm period lasting ~1000 yr. The width of the coastal sequence preserved between successive paleoscarps shows strong correlation with the time interval elapsed between storms. Our fi ndings indicate that diagnostic geophysical and sedimentological signatures of severe erosional events offer new opportunities for assessing the impact and timing of major storms along sandy coasts.

Volumetric Analysis of Overwash Fans Resulting from Tropical Storms on North Hatteras Island, North Carolina

In 1999, Hurricanes Dennis, Floyd, and Irene affected the North Carolina coastline. Although none of these storms made landfall north of Cape Hatteras, the northern Hatteras Island shoreline suffered severe beach erosion and widespread overwash. The volume of three overwash fans located within a 3.75 km section of shoreline in Rodanthe was determined by measuring depth of deposition at selected locations on the fans. Fan area was determined from measurements taken from aerial photographs. The depths of deposition on the fans ranged from 0.2-1.2m, and 30-50m3 per meter length of fan were deposited at the sites. The volumes deposited exceed the amounts recorded during previous storms at locations along the U.S. East Coast. Subaerial sedimentation on barrier islands depends on high magnitude/low frequency events because their higher storm surge and wave heights produce dune breaching. Overwash is not widespread during lower magnitude storms because the water levels are not high enough to result in flow across the barrier. The total volume of overwash on North Hatteras Island was estimated from fan areas measured on aerial photographs in conjunction with the average depth of deposition measured on the Rodanthe fans. The total amount of sediment deposited was estimated to be 48 m3 per meter of fan length. Comparing these overwash volumes to amounts deposited by wind on the barrier island north of Hatteras Island shows that, on an annual basis, overwash far exceeds wind as a mechanism for transferring sediment inland. However, an extrapolation over a longer period to accommodate for temporal variations reveals that the volumes of sediment transferred by overwash and by wind are nearly balanced.