Defence Structures Research Articles

SEARCH FOR CULTURAL IDENTITY IN THE TRADITION OF FORTIFIED STRUCTURES

The country's fast growth in Qatar has recently opened the door to questioning future development directions. The country's need to enhance local identity has promoted many campaigns for conserving local tradition and preserving national heritage, following an opposite direction compared to the recent construction boom in contemporary architecture. Heritage restoration and reuse can be a sustainable strategy to enhance the local tourism offer and improve country identity values with the involvement of local communities. The historical origins of the country are embedded in the defensive functions of many heritage buildings currently undergoing a series of interventions financed by governmental institutions to promote the valorization of national resources and culture. The paper illustrates the conducted analyses and shows how the defensive structures are located in the Qatar territory into three main areas to defend from the invasions from the North-West and the East sides of the country. The results show three main categories of buildings based on their traditional defensive function and location: traditional forts, fortified residential buildings to protect the population and watch towers to provide surveillance. The research highlights how heritage sites still need to be valorized and how the conservation practice can promote sustainable growth and development of the country in the post-oil area.

ZMIEVY VALY. THE PRESENT: SCIENTIFIC ISSUES, TASKS AND PERSPECTIVES

The history of research and the issues of research and protection of wood-earth embankments in the Middle Dnipro region known as Zmiievi Valy (the Dragon Ramparts) are reviewed in the paper. The history of the study of this type of archaeological site is briefly described. In the 19th century, the ramparts were described by several researchers. In the second half of the 20th century, the ramparts were explored by M. P. Kuchera. The research lasted 10 years. As a result of field work, the main characteristics of the constructions are described. The paper presents an outline of the scientific issues of Zmiievi Valy and the defense system of princely Kyiv. The problem of using a separate topo-geodetic service during the construction of a defense system is considered. The main methods of interaction and strengthening of defense lines and the surrounding landscape are outlined. Tasks for future research are set and their prospects are outlined. The connection of the theme of the Zmiievi Valy with many areas of work with the cultural heritage of Ukraine is shown. The main parameters of the future research and protection program are briefly outlined. Among the tasks of the program are the following: 1) Digitization of all scientific publications and archival materials related to the topic of Zmiievi Valy; 2) Collection and digitization of various cartographic and visual materials; 3) Development and implementation of measures for the protection of Zmiievi Valy. Monitoring of the current state of each line of shafts. A comprehensive survey of not only the remains of the ramparts and the surrounding area. 4) Drawing up a management plan for Zmiievi Valy; 5) Development of an advocacy campaign on the subject of Zmiievi Valy; 6) Creation of a unique geo-informational atlas of defense structures and surrounding space. Specific models of the landscape will contribute to the study of various aspects of the functioning of Kyiv’s defense system. Application of information modeling will allow us to move away from abstract statements in the field of military history.
 Zmiievi Valy as a complex sites that have given birth to a certain mythology around them and are wrapped in an ancient local oral folk and cabinet history tradition, still influence the present and have a significant potential to enrich our future.

The impact of coastal realignment on the availability of ecosystem services: gains, losses and trade-offs from a local community perspective

Coastal realignment is the procedure of repositioning or removing coastal defense structures to restore tidal flooding and facilitate the development of intertidal ecosystems in a previously reclaimed area from the sea. A key policy objective of coastal realignment is to increase ecosystem services provided by intertidal ecosystems and thereby contribute to human well-being. However, the social response to coastal realignment is often negative, raising the question as to what extent communities living nearby project locations recognize, value and benefit from the goods and services provided by restored intertidal ecosystems. In this study, we examine public perceptions of ecosystem services gains, losses and trade-offs associated with coastal realignment. We hereby focus on three coastal realignment case study locations in the Southwest delta, the Netherlands. Questionnaires were administered in nearby villages and the collected data (N = 261) were analyzed using random forest regression models. A notable outcome of this study is that local communities often consider coastal realignment interventions to decrease rather than increase the availability of ecosystem services. This points to a discrepancy between how coastal realignment is viewed from a policy perspective and a local community perspective. Changes in the availability of cultural ecosystem services were found to have the highest impact on the level of support for coastal realignment, while the importance attached to provisioning, regulating and supporting ecosystem services was notably lower. In consequence, to increase public support, it will be essential to minimize the loss of cultural ecosystem services, or better yet, find ways to increase cultural ecosystem services through coastal realignment, for instance by creating opportunities for recreation and tourism.

Assessment of social factors that promote the vulnerability of communities to coastal hazards in the Volta estuary in Ghana

Although vulnerability assessments have been widely conducted along the coast of Ghana, they have not focused on the factors contributing to social vulnerability of households and communities to disaster risks. Using an indicator-based approach, this study examines the social factors that affect the exposure, sensitivity and adaptive capacity of households and communities in the Volta estuary, Ghana. Results indicate that all the communities within the study area were exposed to climate change related hazards. However, two communities, Azizanya in Ada East District and Fuveme in Anloga District, were highly exposed with unweighted indexes of 0.50 and 0.76, respectively. Sensitivity among communities was generally high ranging from 0.00 to 0.87 due to several social factors including low household income, high number of children and aged at home, and lack of social amenities such as roads, health facilities, markets, and schools. The communities recorded high adaptive capacity and were able to withstand the ravages of the ocean and the river system. Households and communities developed various adaptation measures such as relocation to nearby communities or higher grounds, open spaces and packing of their belongings on higher objects such as tables, whiles government actions included occasional dredging and constructions of sea defense structures. An integrated, multi-stakeholder approach involving government, non-governmental community-based organisations, communities, households, and other stakeholders is proposed to design and implement a comprehensive disaster management plan to combat climate change related coastal disasters.

Wind Effects on Wave Overtopping at a Vertical Sea Defense

The wind effect on the efficiency of a coastal defense structure is studied in this paper. It is normally assumed that the strength of the wind impact is characterized by the impulse parameter. If it is lower than a certain value, the wind is expected to have a dominant effect on the wave overtopping rate. In contrast to the regular observation, this study reports a new regime of wave overshoot when a low value of the impulse parameter does not lead to increased importance of wind. It is argued that the new regime appears due to the triplet instability previously studied by others. The variation of the standing wave height and the overshooting jet between the sequential cycles results in independence of the overtopping rates of the wind speed.

Coevolution of Extreme Sea Levels and Sea‐Level Rise Under Global Warming

AbstractDesign of coastal defense structures like seawalls and breakwaters can no longer be based on stationarity assumption. In many parts of the world, an anticipated sea‐level rise (SLR) due to climate change will constitute present‐day extreme sea levels inappropriate for future coastal flood risk assessments since it will significantly increase their probability of occurrence. Here, we first show that global annual maxima sea levels (AMSLs) have been increasing in magnitude over the last decades, primarily due to a positive shift in mean sea level (MSL). Then, we apply non‐stationary extreme value theory to model the extremal behavior of sea levels with MSL as a covariate and quantify the evolution of AMSLs in the following decades using revised probabilistic sea‐level rise projections. Our analysis reveals that non‐stationary distributions exhibit distinct differences compared to simply considering stationary conditions with a change in location parameter equal to the amount of MSL rise. With the use of non‐stationary distributions, we show that by the year 2050 many locations will experience their present‐day 100‐yr return level as an event with return period less than 15 and 9 years under the moderate (RCP4.5) and high (RCP8.5) representative concentration pathways. Also, we find that by the end of this century almost all locations examined will encounter their current 100‐yr return level on an annual basis, even if CO2 concentration is kept at moderate levels (RCP4.5). Our assessment accounts for large uncertainty by incorporating ambiguities in both SLR projections and non‐stationary extreme value distribution parameters via a Monte Carlo simulation.

Mapping the Past: Preliminary Assessment of Survey of Archaeological Sites and Monuments in District Bhimber, AJ&K (2020-21)

Archaeological research has played a crucial role in preserving the cultural heritage of the Bhimber region. Numerous researchers and explorers have contributed to documenting its historical monuments and sites, but its potential has not been exploited at large. To document the archaeological potential of the District Bhimber, a survey was proposed. This paper focuses on the preliminary results of this survey and documentation of archaeological sites and monuments in the Bhimber district, AJ&K, conducted between 2020-21. The main objective of the survey was to find new sites and monuments and document in detail the exposed features of already reported and new sites and monuments. Traditional field walk following village to village survey methodology equipped with proforma has been adopted for the documentation of sites and monuments. Through these efforts, over fifteen archaeological sites and historic monuments have been identified and documented detail in District Bhimber, with the majority located in Tehsil Bhimber. The sites comprise of religious structures such as temples, gurdwaras, mosques, as well as residential and defensive structures such as forts and havelis mainly associated to Sikh and Mughal period. The discovery of these significant structures emphasizes the need for continued research and preservation efforts to safeguard the cultural heritage of the region for future generations. There is still a need of large-scale survey to document the archaeological sites and monuments in other regions of the Bhimber as well as AJ&K.

El futuro de la Junta Interamericana de Defensa y su Relación con la Integración yResiliencia del Hemisferio Occidental

XXI Century speeded up the changes in the defense and security landscape, mainly by the interference of new technologies and the diversification of actors that influence the field of action in multiple domains. These changes must be studied and analyzed continuously to keep defense and security structures and alliances up to date and capable of facing all alternative actions, with a readiness that makes them always one step ahead of the opposing strategy. This article aims to identify, throughout a prospective analysis, the challenges and threats that are being addressed and will be faced by the Inter-American Defense Board (IADB) in the future's complex multidimensional, multi-domain, and transnational threats landscape. Additionally, the paper seeks for international cooperation opportunities that could provide IADB tools and new procedures to improve its capabilities, studying another regional and complex alliance such as the European Union, by a defense and security approach. The actions proposed not only will reinforce the own IADB but strengthen the Organization of American States (OAS) to reach a pioneering role as an international alliance committed to people’s equity and the defense of democracy, in a real non-polarized, and multilaterals world.

Formation of working equipment of increased efficiency for earthmoving and transport machines

Problem. The problem is low productivity when performing earthworks by earthmoving machines on long construction sites in road, transport, land reclamation construction, during repair and laying of main pipelines, construction of defense structures, which are related to the development of soil and its lateral transportation due to the predominant use machines of cyclic action. Increasing the efficiency of soil digging by bucket earthmoving and transport machines by reducing soil digging resistance and increasing the volume of soil in the bucket. Goal. Formation of new technical solutions of highly efficient working equipment of earthmoving and transport machines. Methodology. System analysis, classification and synthesis of new effective structural elements for the creation of working equipment of earthmoving and transport machines of increased efficiency. Physical modeling to clarify the physical essence of the work process and the performance of the proposed structures. Results. New technical solutions of cutting, transporting, limiting components for the creation of highly efficient earthmoving and transport machines are proposed. Originality. Combining the process of digging the soil with its simultaneous transportation in the direction with the specified parameters. Practical value. The designs of working equipment of earthmoving and transport machines were proposed with the use of cutting and throwing devices for effective continuous lateral transportation of soil and filling of bucket working bodies.

Study on anti-penetration performance of Kevlar reinforced honeycomb liquid-filled cabin on warship: Experimental verification and numerical analysis

The water hammer effect produced when fragments penetrate the liquid tank on warship will cause integral expansion and damage to the structure of the liquid tank. In this paper, a kind of liquid-filled honeycomb structure reinforced by Kevlar fiber tube is designed, and the mechanism of Kevlar fiber tube reinforced honeycomb liquid-filled structure against fragmentation is analyzed. The numerical model of Kevlar reinforced honeycomb liquid-filled structure is established, and the process of high-speed fragments penetrating the defense structure is analyzed by ALE calculation method, and the armor-piercing test of liquid-filled structure is carried out, which verifies the reliability of simulation calculation. The influence of honeycomb core layer and Kevlar fiber tube on the defense of liquid-filled structure against high-speed fragment is further discussed. In addition, an air compartment is arranged in the honeycomb liquid-filled structure to weaken the water hammer effect. It is found that the air compartment has a slight decrease in the ability to weaken the fragment velocity, but it greatly reduces the damage degree of the structure caused by fragment penetration.

Impacts of repeated coastal flooding on soil and groundwater following managed dike realignment

Coastal defense structures (e.g., dikes, seawalls) protect vulnerable communities along marine coastlines and estuaries from the physical and chemical influences of adjacent water bodies. These structures are susceptible to overtopping or breaching by tides and waves, with risks amplified by climate change-induced sea-level rise. Repeated inundation by saline water can contaminate freshwater resources and salinize soil, impacting land-use activities, including agricultural productivity. Managed ecosystem-based dike realignment and salt marsh restoration can provide alternatives to traditional coastal adaptation approaches. We assess the changes to soil salinity at a managed dike realignment project prior to the transformation from a diked terrestrial environment to an estuarine environment. Baseline data are compared to conditions following 8–10 months of intermittent flooding at spring tides.Results show that an increase in salinity occurred over the entire site in the shallow subsurface, with the most significant contamination occurring in low-lying areas. Bulk soil electrical conductivity (salinity proxy) measured from geophysical surveys increased from the previous freshwater condition of ∼300 μS/cm to over 6000 μS/cm following <20 flood events, while successive flooding resulted in increased soil moisture as infiltrated floodwater propagated to greater depths. Sediment deposition occurred at high rates, with up to 4 cm of sediment deposited per flood, converting much of the previously cultivated land into tidal mudflats. Deeper sediments and groundwater (i.e., >1.8 m depth) were not impacted over the time scale of this research. This study demonstrates that intermittent shallow flooding can rapidly increase moisture content and soil salinity in surficial sediments and, in turn, adversely impact conditions suitable for agricultural crop production. The realignment zone serves as an engineered analog of coastal flooding, presenting an opportunity to investigate how low-lying coastal environments may experience regular flooding in the future due to sea-level rise and intensifying coastal storms.

Spatial analysis of provision the population of Kharkiv with civil defense facilities

The article analyzed the territorial aspect of the distribution and capacity characteristics of civil defense structures in the city of Kharkiv, comparing it with the population size. In the first stage, population density was calculated for specific areas within the maximum permissible radius of the nearest available shelter. The spatial characteristics of the location (level of clustering) and capacity of the defense structures were examined for these same areas. Finally, the population size was correlated with the capacity of the civil defense structures, and spatial clustering of the identified areas was conducted based on this attribute. The geostatistical method of spatial interpolation was used to determine population density in specific areas and fill gaps in the primary data. The application of this method required the following sequential procedures: transforming the primary data according to a normal distribution, constructing a semivariogram model of the transformed variables, aggregating the model into a surface, and defining target polygons. During the calculation of the territorial provision of various types of shelters in the city of Kharkiv, the following sources were utilized: a layer of point objects from the interactive map of open data on the Kharkiv Geoportal (to determine the locations and types of protective structures), and information from the website of the non-commercial enterprise «Emergency Medical Care and Disaster Medicine Center» of the Kharkiv Regional Council (to update information on the capacity of storage facilities and anti-radiation shelters). The Global Moran’s Index and Local Moran’s Index are statistical methods used to assess spatial autocorrelation, which is the degree of clustering or spatial pattern in a variable across a defined area. In this case, they were employed to evaluate the spatial autocorrelation of the capacity of civil defense structures in specific parcels in Kharkiv. The Global Moran’s Index indicated a high level of clustering of areas based on this attribute. Using the Local Moran’s Index, parcels were classified into five object classes: High-High cluster (HH), Low-Low cluster (LL), a high-value outlier surrounded by low-values (HL), a low-value outlier surrounded by high-values (LH), and areas without cluster or outliers (non-significant). The scientific novelty of the article, compared to related studies on a similar topic, lies in the utilization and transformation of a hexagonal grid of population density distribution in the city of Kharkiv, in accordance with the research requirements. In the conclusions, based on the results of cluster analysis and through the adaptation of the tectological principle of the weakest link to the realities of the present, a comprehensive sequential strategy for addressing the shortcomings of territorial provision of civil defense structures in ensuring the population of Kharkiv was proposed.

Simulating hypervelocity impacts into rubble pile structures for planetary defense

Kinetic impactors are one of the most mature technologies for planetary defense and this technique was tested for the first time by NASA's Double Asteroid Redirection Test (DART) mission. The material and physical properties of the asteroid are very important in understanding the efficacy of a kinetic impactor. To constrain how the local topography of an impactor alters the response to the hypervelocity impact of a kinetic impactor, we used the adaptive smoothed particle hydrodynamics code, Spheral++, to impact plates into a rubble pile asteroid. By varying both the impact location and the strength between the boulders and regolith of the formed asteroid, we find that variations in the rubble pile contributes approximately 10% uncertainty to the resulting momentum enhancement in regolith dominated impacts. We further demonstrate that the craters produced from the impacts into the rubble pile are wide, shallow, and show deviations from symmetry due to the presence of boulders on the surface near the impact site. These simulations help us constrain the potential outcomes that may occur from a hypervelocity kinetic impact in a planetary defense scenario.

A report of wars in Glamorgan: evidence of damage, wreckage, and heritage?

Glamorgan is a historic county of Wales, limited south and west by the Bristol Channel, in which defensive structures are a frequent and a persistent topic regarding its heritage and history. Apart from Wales numerous castles, hillforts and fortifications, the country has also relics from the Great War and the Second World War. Several of them lost or demolished, however many of them still endure. Then, what role those remaining relics play on society? It is common to accept that the purpose of them was self-protective, providing defence from attack during raids and warfare. However, when conflicts and war are past and people’s interest in their history and heritage is progressively increasing through the years, how did Wales manage those remains and what do they mean? Some have argued that maintaining or conserving military remains is dependent on future management by the government and that it demands a deliberate re-framing of history. Based on those facts, this article has the objective to show and discuss evidence of damage, wreckage and defeat over time caused by war in the historic county of Glamorgan. As means to achieve it, significant use of maps and pictures will show the extent of damage and, individual case studies will be considered throughout this article to contribute to the discussion of different types of heritage and stories lost over time.

NEW FIND OF THE SCYTHIAN SWORD NEAR MOTRONYNSKE HILLFORT

In spring 2023 two kilometers south-west of the well-known Motronynske hillfort of Scythian Age on a flat plateau the iron Scythian sword was found out by chance on a little depth. In the Steppe and Forest-Steppe of North Pontic region swords and daggers of this type date to the second half of 6th—5th cc. BC (rather by the first half of the latter century). Near Motronynske hillfort a few finds of Scythian swords and daggers are known but swords of similar type have not occurred before.&#x0D; The site was examined by the author. It is a flat plateau with small depressions, located near the road to Hruskivka and Kamianka villages. Nearby the kurgan burial ground was located, investigated in 2018 by an expedition headed by O. D. Mohylov.&#x0D; The sword was found at a depth of 0.5 m from the modern surface, in forest loam. No cultural layer can be traced here but to the south of the site there are remains of defensive structures in the form of an earthen rampart with a moat that covers the plateau spurs from the side of Hruskivka. Near this rampart in 2019, a bronze triangular arrowhead with a spike was found, which according to A. I. Meliukova’s classification belongs to type 1, group 1, division III.&#x0D; In recent years several more swords and daggers of the 7th—5th centuries BC have been accidentally found in this area of the Kholodnyi Yar tract. This sword has a simple antenna-shaped pommel and butterfly-shaped cross-bar, i. e., according to the well-known classification of A. I. Meliukova, it belongs to the edged weapons of the II department of the 2nd type, which was widespread in the 6th — first half of the 5th century BC. The sword is 61.3 cm long, double-bladed, with a blade tapering in the last third of its length, well preserved. It weighs 650 grams. Finds of the edged weapons of infighting near the largest settlement of the Scythian Age in the Tyasmin-river-basin, presumably, are the evidence of a military collision of it’s inhabitants with the representatives of the nomadic world of Steppe.

Depth-dependent flexural behavior of plain and bar-reinforced ultra-high-performance hybrid fiber-reinforced concrete –analytical, numerical, and uncertainty modeling

Ultra-high-performance concrete (UHPC) has been the perfect material for precast, marine, defense, and high-rise structures due to its outstanding features, including high ductility, compressive strength, and enhanced durability. UHPC technology has gained wide attention for various applications. Government initiatives, however, have largely led to the development of these projects. The UHPC has not been widely adopted since there are no reliable and accurate codified formulas for predicting load-carrying capacity, which remains a significant obstacle. First, this study evaluated the applicability of popular international design guidelines for predicting the moment capacity of fiber-reinforced UHPC (UHFRC) beams. In addition, a nonlinear numerical approach for a robust model to predict the moment–curvature of UHFRC beams was developed and validated. The structural safety of UHFRC beams using a multivariate nonlinear probability model was verified. As beam depth increased, the reliability index decreased slightly, which could be attributed to its significant impact on the reliability index. The presence of reinforcement bars significantly affects the reliability index as its percentage increases. All reinforced beams with a depth of 120 mm or more and steel bars had a reliability index greater than 3.0. In the study, bar reinforcement is demonstrated to be a vital component of the UHFRC beam for ensuring structural integrity.

Variation of shell ornamentation with latitude and water depth-A case study using living brachiopods.

As a potential anti-predatory defensive structure, the shell ornamentation of marine calcifiers is usually used to understand the macro coevolution of the interactions between predators and preys. Marine calcifiers' shell ornamentation complexity is generally believed to vary negatively with latitude and water depth. In this paper, we explored the association between shell ornamentation and latitude/bathymetry using the latest global database of living brachiopods. We found that (1) ~59% of living brachiopods species are characterized by smooth shells and that (2) there is no statistically significant linear trend, either positive or negative, between the ornamentation index and latitudes nor with water depths. Both findings are puzzling for living brachiopods as they are sharply contrasted to the patterns of fossil brachiopods whereby the latter, especially Paleozoic brachiopods, are known to exhibit (1) a much greater ornamentation diversity and (2) (at least for the geological periods that have been studied) a linear latitudinal gradient of ornamentation complexity existed. The reasons why living brachiopods have such a high proportion of smooth or weakly ornamented shells and fail to demonstrate an unequivocal linear latitudinal ornamentation gradient were explored and are linked to a multitude of potential factors rather than uniquely only to the predation pressure. Among these, the most plausible factor seems to be the cryptic (refuge-type) habitats (e.g., deep waters, cold polar regions, and submarine rock caves) that living brachiopods have been adapted to due to their low metabolism, where predation pressure is low, allowing brachiopods to enact the predator avoidance strategy rather than having to manufacture robust shell ornamentation to survive in an otherwise highly engaged predator-prey global marine ecosystem.

Hillforts of the Scythian Period in the Middle Course of the Seim River

Despite many years of studies of the Scythian Age hillforts of the Seim River Putyvl region, their research has only just begun. This is largely the merit of the works of the Putyvl archaeological expedition, which surveyed all the fortified settlements of the region during 2012—2016. New topographic plans were created, the peculiarities of the cultural layer of a particular settlement were clarified. The research conducted allows identifying the general characteristics of the fortified settlements of the region. All the hillforts are located on promontories, with one or more ramparts on the field side. A characteristic feature is the presence of two or more sharp ridges, which gently descend to the floodplain. Minor studies of defensive structures were conducted only at three sites. The presence of a defensive ditch is assumed, although it can be traced only visually at two sites. In addition, a significant part of the hillforts is fortified by slopes. Based on the cultural layer we can distinguish three groups: the fortified settlement with a thick layer which has existed for a long time; the fortified settlement with a layer approximately 0.5 m thick; the fortified settlement with a thin layer and a small number of finds and objects. The latter are probably unfinished hillforts or administrative centres, combining several unfortified settlements. A comprehensive research of the material complex, given the small number of finds, is impossible. However, even with a superficial analysis there can be traced the connection of the Middle Seim tribes with the Yukhniv population of the forest belt. It is possible to assume the presence of mixed marriages, which led to the appearance of specific forms of ceramic vessels and some items in the population of the northern part of the Left Bank forest-steppe. The question about the time of existence of the sites in the Seim River Putyvl region remains open. Preliminarily we can speak about the middle of the 6th—4th centuries BC. However, in the 4th century BC there was only one fortified settlement – Shyriaievе.

Perspectives on factors that influence local communities’ vulnerability to coastal floods in Ketu South Municipality of Ghana

Vulnerability studies in relation to coastal floods in Ghana have generally focused on assessing the biophysical vulnerability and flood hazard modelling - rather than exploring the combination of both biophysical and socioeconomic factors that affect the vulnerability of coastal communities to floods. In response, this study aimed to explore the factors that influence the vulnerability of coastal communities in Ketu South Municipality, Ghana, to floods. These communities remain vulnerable to coastal flood events from storm surges, high tidal waves, lagoon overflow and heavy rainfall. However, the local conditions that make these communities vulnerable is poorly understood. The study used data from eight (8) in-depth interviews, nine (9) Focus Group Discussions and 354-household survey to explore local vulnerability factors in the study area. Results show that factors such as low land elevation, inadequate sea defence structures, high flood frequency, large flood extent, long flood duration, flood impacts, are among the exposure factors influencing vulnerability in the study area. It also shows that socioeconomic factors; such as weak demographic groups, low-income levels, low level of education, and some local adaptation measures plus external flood relief supports from National Disaster Management Organization (NADMO) influence the vulnerability of the communities. The result further revealed salt production activities, and relocating to flood prone areas, as well as rise in coastal water table and rapid shoreline erosion are the observable vulnerability factors in the study area whiles gender was a significant social factor influencing flood preparedness. These results can be useful for flood disaster management programs.

Wave Overtopping at Sea Dikes on Shallow Foreshores: A Review, an Evaluation, and Remaining Challenges

Wave overtopping is a critical parameter in the design of coastal defense structures. Nowadays, several empirical formulations based on small-scale experiments are available in the literature to predict the mean overtopping discharge at dikes on shallow foreshores. Although the accuracy of the predictions has improved due to each approach’s contributions, the formulations’ performance depends on their range of applicability. In engineering applications, it is important to know the performance and limitations of the different formulas. This work presents a new experimental dataset focused on very shallow and extremely shallow foreshore conditions for a range of foreshore slopes (i.e., 1/20, 1/35, 1/50, and 1/80) and relative water depths. The recent developments in wave overtopping research on very shallow and extremely shallow foreshore conditions have been reviewed using this dataset to reflect the existing uncertainties and challenges in the wave-overtopping literature. We find that predicting wave overtopping for extremely shallow foreshore conditions still requires improvement. Additional research is needed to understand the (residual) influence on the wave overtopping of the foreshore slope and relative magnitude of the infragravity wave height to the sea-swell wave height at the dike toe, especially for extremely shallow foreshore conditions. The variation in performance of the formulas for different foreshore slopes is demonstrated. Finally, some of the remaining uncertainties that need further exploration are discussed.