Hasil untuk "Harbors and coast protective works. Coastal engineering. Lighthouses"

Cheikh Omar Tidjani Cisse, Rafael Almar, Mamadou Sadio

Coastal storms represent a major environmental issue and constitute an important challenge for coastal flood management. This study analyzes the frequency and characteristics of storms on the Senegalese coast between 1993 and 2023, focusing on four coastal cities: Dakar, Saint-Louis, Mbour, and Cap-Skring. The analysis is based on wave data from the ERA5 model and on meteorological and oceanographic data from different models. Storms were detected using the Peak Over Threshold (POT) method, based on the 95th percentile and fitted to a generalized Pareto distribution (GPD). The results reveal a contrasted spatial distribution of coastal storms, with a higher occurrence in Dakar and Saint-Louis. An apparent increase in the frequency of storms is observed in Saint-Louis, Mbour, and Cap-Skring, while an apparent decrease is noted in Dakar; however, these trends are not statistically significant. Extreme coastal water levels (ECWL) associated with storms show an opposite evolution, with an apparent decrease in the first three regions and an apparent increase in Dakar. The most intense and longest storms, in terms of energy content (Es), are mainly observed in Dakar and Saint-Louis. A linear relationship is highlighted between the duration and intensity of storms. Storm occurrence shows a strong seasonal modulation, with a predominance during the dry season (November to May). The most energetic storms are mostly generated by waves from the west to west-northwest direction in Dakar and Saint-Louis, while Mbour and Cap-Skring present a wider directional window. This first analysis at the scale of the Senegalese coast provides essential elements for understanding the risk of coastal storms and constitutes support for coastal flood management in a context of climate change.

Kun Qi, Jennifer G. Duan, Chuck Gerba et al.

Pathogen transport in irrigation canals was simulated via a one-dimensional hydrodynamic and sediment transport model. The governing equations are St. Venant for sediment-laden flow and convection and a diffusion equation for pathogen transport in water and sediment. The first-order kinetic theory was applied to estimate the die-off and growth of a pathogen in water and sediment. The coupled equations were solved numerically via the HLLC approximate Riemann solver. The model was verified via laboratory experimental data from Escherichia coli (E. coli), Bacteriophage MS2 (MS2), and Enterobacteria phage PhiX174 (PhiX174). A comparison of the simulated and measured pathogen concentrations revealed that the number of pathogens in the water increased sharply with increasing shear stress and reached a constant value at a given flow discharge. These results suggest that pathogen concentrations in water are influenced by flow dynamics and sediment on the bed, especially pathogen entrainment and transport with sediment load.

Didier M. de Bakker, Chris T. Perry, Alice E. Webb

The long-term development of coral reef frameworks and the net vertical accretion of reefs fundamentally underpins the provisioning of most reef-related ecosystem services. One area of particular concern at present is how rates of reef accretion are changing under ecological decline and what the consequences of this may be for the capacity of reefs to keep pace with near-future sea-level rise (SLR). This may have major implications for the capacity of reefs to maintain their coastal protective functions and to support reef island stability. Both are issues relevant to understanding future tropical coastal risk. Long-term (millennial timescale) rates of reef accretion are relatively well constrained, including through past periods of sea-level fluctuations. However, widespread and persistent ecological degradation of coral communities has caused many reefs to diverge significantly from their past accretion trajectories. This renders historical analogues increasingly unreliable for projecting future accretion potential. Addressing this necessitates a reorientation towards considering reef accretion rates across shorter (ecological to geomorphic) timescales, i.e., over years to multi-decades. This is essential if we are to better constrain contemporary reef accretion rate and SLR interactions at timescales relevant to predicting emerging coastal risks and understanding future implications for reef-derived benefits. Here, we review existing approaches for quantifying vertical reef accretion rates of modern reefs. These methods span data recovered from fossil outcrops or core-derived records, the conversion of carbonate budget data, direct in situ measurements and emerging remote sensing and image-based techniques. The review explores the advantages and limitations of these different approaches and outlines options for developing an integrated framework to link past, present and future reef accretion potential.

C. Gabriel David, Johanna Kremer, M Ashwini et al.

Coastal areas face unprecedented challenges from accelerating sea-level rise, increasing urbanisation and biodiversity loss, necessitating sustainable coastal protection strategies that go beyond traditional engineering approaches: While Nature-based Solutions (NbS) offer ecological benefits, their implementation faces constraints in space, timely readiness and standardisation. Hybrid Nature-based Solutions (HNbS) have emerged as promising alternatives, yet current taxonomic classifications remain ambiguous and insufficient to accommodate emerging technologies. This synthetic review analyses the evolution and current role of NbS in coastal climate change adaptation through a comprehensive juxtaposition of design principles and functional mechanisms of engineered and nature-based coastal defences. The review synthesises knowledge from sustainable climate adaptation and digital fabrication literature to establish precise taxonomic classifications for solutions that integrate engineered and nature-based approaches, namely HNbS. The analysis reveals gaps in the existing HNbS taxonomy, particularly regarding structures enabled by digital fabrication technologies. The three identified, distinct categories of HNbS are: (1) Hybrid Nature-based Strategies, combining engineered and natural elements at planning scales; (2) Hybrid Nature-based Modules, integrating both components within individual structures; and (3) Confluent Hybrid Nature-based Solutions, representing an emerging category where engineering and natural systems converge at material or microorganism scales, offering distinctly engineered infrastructures with natural characteristics. While contemporary hybrid approaches are being implemented, Confluent Hybrid Nature-based Solutions under research, may face a critical timing mismatch due to a gap between lengthy innovation timelines and urgent adaptation needs. Dynamic Adaptive Policy Pathways provide a framework for strategically accommodating these emerging innovations, enabling early-stage solutions and performance demonstration under real-world conditions. The new taxonomic framework outlined in this study prevents imprecise terminology and provides a foundation for robust, low-regret coastal adaptation strategies addressing contemporary and future coastal pressures like climate change impacts and biodiversity conservation requirements.

Mojtaba Mehraein, Vahid Reza Zendehnam, Seyed Hossein Mohajeri et al.

The scour hole caused by 3-dimensional wall jets (3DWJ) is a serious problem downstream of dams and power stations. The current study utilized a newly created hybrid machine learning (ML) model to predict the changes in the dimensions of the primary scour hole over time caused by a 3DWJ. To fill the gap in the available knowledge, different experiments were done using uniform and non-uniform sediment. ML models and the linear regression were used to derive the prediction models. The results of the current study showed that the ML models have better accuracy than the linear regression model. Among all the developed hybrid ML models, the accuracy of the hybridized Categorical Boosting (CatBoost) with Gray Wolf Optimization algorithm (GWO-CB) yielded superior predictions. Sensitivity analysis confirmed the densimetric Froude number and the scouring time were important predictors. The effects of the expansion ratio on maximum scour depth and ridge height were the less important. However, the expansion ratio effects were larger than the effects of the tailwater depth ratio and sediment size ratio in the development of the scour hole in the streamwise and spanwise directions. The accuracy of GWO-CB models was considerably higher than the models previously applied in the literature. The proposed methodology revealed a robust and reliable model for predicting the scour hole dimensions.

Chinomnso C. Onwubiko, Denis Worlanyo Aheto

Coastal habitats are crucial in mitigating the impact of coastal hazards on society. However, the shortage of information about the role of these habitats in reducing floods in Rivers State, Nigeria, is limited. This study aims to assess the contribution of mangrove habitats in protecting coastal communities from flooding using the InVEST coastal vulnerability model (version 3.10.2). The model analyzes various data inputs and assigns relative numbers, ranging from 1 to 5, indicating different levels of exposure. Data on population, bathymetry, shoreline type, land use land cover, and continental shelf were obtained from relevant websites and the InVEST model package. The findings indicate that the mangrove habitats in Rivers State offer minimal protection against coastal flooding due to their degraded state caused by oil spills and over-exploitation. Additionally, sandy beaches provide little to no protection, and the socio-economic conditions in the communities contribute to increased vulnerability to flooding. The study recommends awareness programs to educate the public about the importance of mangroves for coastal protection in addition to their conservation and restoration.

Benjamin D. Jones, Mark E. Dickson, Murray Ford et al.

Coastal landforms and associated archaeological records are at risk of erosion from a combination of rising sea levels and increasingly frequent high-intensity storms. Improved understanding of this risk can be gained by braiding archaeological and geomorphological methodologies with Indigenous knowledge. 1 In this article, archaeological, geomorphological and mātauranga (a form of Indigenous knowledge) are used to analyse a prograded Holocene foredune barrier in northern Aotearoa/New Zealand. Anthropogenic deposits within dune stratigraphy are radiocarbon-dated and used as chronological markers to constrain coastal evolution, alongside geomorphological analyses of topographic data, historical aerial photographs and satellite imagery. These investigations revealed that the barrier is eroding at a rate of 0.45 m/year. A midden in the foredune, which has been radiocarbon dated to 224–270 B.P. (95% Confidence), has been exposed by coastal erosion, confirming that the barrier is in the most eroded state it has been within the past ~300 years. Vertical stratigraphy reveals the presence of midden and palaeosol deposits capped by dune sand deposits in the foredune, indicating that vertical accretion of the foredune continued over the last ~200 years, despite the barrier now being in an eroding state. Mātauranga played a vital role in this project, as it was the coastal taiao (environmental) monitoring unit of Patuharakeke (a Māori sub-tribe) that discovered the midden. The ecological mātauranga shared also played a vital role in this project, adding experiential evidence to empirical observations. The work of local Indigenous groups, like Patuharakeke, demonstrates the active use of mātauranga, woven with Western science methods to preserve or capture the knowledge contained within archaeological sites at risk of being lost to coastal erosion. In this study, we present a method for weaving mātauranga, geomorphological and archaeological approaches to gain a deeper understanding of coastal landscape development.

Zhonghao Zhao, Yuan Xu, Xianye Wang et al.

The erodibility of sediment mixtures is a key factor in sediment dynamic processes and morphological evolution in coastal environments. However, it remains insufficiently understood. In the current study, the critical shear stress of sediments is analyzed with different mud contents and consolidation degrees from experimental results and previous studies. The results indicate that the critical shear stress increases with clay content, peaking at 30% clay content, and then gradually decreasing. Compared to the solid volume fraction of mud (clay and silt), the solid volume fraction of clay shows a higher relation with the critical shear stress of sand-mud mixtures. The role of the consolidation degree in the erodibility of sediment mixtures was quantified through consolidation experiments, revealing an exponential relation between critical shear stress and consolidation coefficient. An empirical equation for the critical shear stress is proposed to consider the mud content, the solid volume fraction of clay, and the consolidation degree. This equation is applicable to mixed sediment over the full range of mud content and varying consolidation degrees. It has a simple form, is easier to apply, and outperforms other empirical equations (RMSE = 0.62; R2 = 0.73).

Mohammad Mehdi Farzanmehr, Jahanshir Mohammadzadeh-Habili

A sharp-crested weir is the simplest type of weir and is mainly used for discharge measurement in open channels. The surface profile of an ogee weir also is designed based on the lower nappe profile of the free jet passing over a sharp-crested weir. In the current study, influences of sedimentation on the discharge coefficient and lower nappe profile of a sharp-crested weir were experimentally investigated. The results indicated that for a specific discharge value, an increase in upstream sedimentation depth results in the reduction in the water level of the approach flow to the sharp-crested weir, and, consequently, a reduction in the weir water head. As the discharge coefficient is inversely influenced by the weir water head, increases in the sedimentation depth resulted in raising the discharge coefficient of the sharp-crested weir up to 42%. Furthermore, the results indicated that with increases in upstream sedimentation depth, the lower nappe profile of the free jet passing over the sharp-crested weir tends toward that of a vertical drop. Under upstream sedimentation, the discharge coefficient of the sharp-crested weir is mainly influenced by the weir's effective height (difference between weir height and sedimentation depth) and it is minimally influenced by sediment grain sizes. Using the experimental results supported by dimensional analysis, the discharge coefficient of the sharp-crested weir was accurately derived as an increasing function of the ratio of weir water head to weir effective height.

Anna R. Armitage, Sabine Dittmann, Alice R. Jones et al.

Wetlands in hypersaline environments are especially vulnerable to loss and degradation, as increasing coastal urbanization and climate change rapidly exacerbate freshwater supply stressors. Hypersaline wetlands pose unique management challenges that require innovative restoration perspectives and approaches that consider complex local and regional socioecological dynamics. In part, this challenge stems from multiple co-occurring stressors and anthropogenic alterations, including estuary mouth closure and freshwater diversions at the catchment scale. In this article, we discuss challenges and opportunities in the restoration of hypersaline coastal wetland systems, including management of freshwater inflow, shoreline modification, the occurrence of concurrent or sequential stressors, and the knowledge and values of stakeholders and Indigenous peoples. Areas needing additional research and integration into practice are described, and paths forward in adaptive management are discussed. There is a broad need for actionable research on adaptively managing hypersaline wetlands, where outputs will enhance the sustainability and effectiveness of future restoration efforts. Applying a collaborative approach that integrates best practices across a diversity of socio-ecological settings will have global benefits for the effective management of hypersaline coastal wetlands.

Tim Wittenborg, Ildar Baimuratov, Ludvig Knöös Franzén et al.

The aerospace industry operates at the frontier of technological innovation while maintaining high standards regarding safety and reliability. In this environment, with an enormous potential for re-use and adaptation of existing solutions and methods, Knowledge-Based Engineering (KBE) has been applied for decades. The objective of this study is to identify and examine state-of-the-art knowledge management practices in the field of aerospace engineering. Our contributions include: 1) A SWARM-SLR of over 1,000 articles with qualitative analysis of 164 selected articles, supported by two aerospace engineering domain expert surveys. 2) A knowledge graph of over 700 knowledge-based aerospace engineering processes, software, and data, formalized in the interoperable Web Ontology Language (OWL) and mapped to Wikidata entries where possible. The knowledge graph is represented on the Open Research Knowledge Graph (ORKG), and an aerospace Wikibase, for reuse and continuation of structuring aerospace engineering knowledge exchange. 3) Our resulting intermediate and final artifacts of the knowledge synthesis, available as a Zenodo dataset. This review sets a precedent for structured, semantic-based approaches to managing aerospace engineering knowledge. By advancing these principles, research, and industry can achieve more efficient design processes, enhanced collaboration, and a stronger commitment to sustainable aviation.

Nasir U. Eisty, Jeffrey C. Carver, Johanna Cohoon et al.

In the evolving landscape of scientific and scholarly research, effective collaboration between Research Software Engineers (RSEs) and Software Engineering Researchers (SERs) is pivotal for advancing innovation and ensuring the integrity of computational methodologies. This paper presents ten strategic guidelines aimed at fostering productive partnerships between these two distinct yet complementary communities. The guidelines emphasize the importance of recognizing and respecting the cultural and operational differences between RSEs and SERs, proactively initiating and nurturing collaborations, and engaging within each other's professional environments. They advocate for identifying shared challenges, maintaining openness to emerging problems, ensuring mutual benefits, and serving as advocates for one another. Additionally, the guidelines highlight the necessity of vigilance in monitoring collaboration dynamics, securing institutional support, and defining clear, shared objectives. By adhering to these principles, RSEs and SERs can build synergistic relationships that enhance the quality and impact of research outcomes.

Kevin Hermann, Sven Peldszus, Jan-Philipp Steghöfer et al.

Software security is of utmost importance for most software systems. Developers must systematically select, plan, design, implement, and especially, maintain and evolve security features -- functionalities to mitigate attacks or protect personal data such as cryptography or access control -- to ensure the security of their software. Although security features are usually available in libraries, integrating security features requires writing and maintaining additional security-critical code. While there have been studies on the use of such libraries, surprisingly little is known about how developers engineer security features, how they select what security features to implement and which ones may require custom implementation, and the implications for maintenance. As a result, we currently rely on assumptions that are largely based on common sense or individual examples. However, to provide them with effective solutions, researchers need hard empirical data to understand what practitioners need and how they view security -- data that we currently lack. To fill this gap, we contribute an exploratory study with 26 knowledgeable industrial participants. We study how security features of software systems are selected and engineered in practice, what their code-level characteristics are, and what challenges practitioners face. Based on the empirical data gathered, we provide insights into engineering practices and validate four common assumptions.

Lekshmi Murali Rani

The study of behavioral and social dimensions of software engineering (SE) tasks characterizes behavioral software engineering (BSE);however, the increasing significance of human-AI collaboration (HAIC) brings new directions in BSE by presenting new challenges and opportunities. This PhD research focuses on decision-making (DM) for SE tasks and collaboration within human-AI teams, aiming to promote responsible software engineering through a cognitive partnership between humans and AI. The goal of the research is to identify the challenges and nuances in HAIC from a cognitive perspective, design and optimize collaboration/partnership (human-AI team) that enhance collective intelligence and promote better, responsible DM in SE through human-centered approaches. The research addresses HAIC and its impact on individual, team, and organizational level aspects of BSE.

Adrian Bajraktari, Michelle Binder, Andreas Vogelsang

Modern science is relying on software more than ever. The behavior and outcomes of this software shape the scientific and public discourse on important topics like climate change, economic growth, or the spread of infections. Most researchers creating software for scientific purposes are not trained in Software Engineering. As a consequence, research software is often developed ad hoc without following stringent processes. With this paper, we want to characterize research software as a new application domain that needs attention from the Requirements Engineering community. We conducted an exploratory study based on 8 interviews with 12 researchers who develop software. We describe how researchers elicit, document, and analyze requirements for research software and what processes they follow. From this, we derive specific challenges and describe a vision of Requirements Engineering for research software.

Giuliana Dos Santos Pinheiro, Lise Tupiassu, Ana Elizabeth Neirão Reymão

This article explores the institutionalization of multiscale management in the Brazilian coastal zone, following the National Coastal Management Plan. It employs Secchi’s COQ3 framework to analyze and shed light on this subject. The study uses an exploratory and qualitative approach, employing case studies. It examines the evolution of coastal management in Brazil and highlights the challenges of multiscale management institutionalization. Drawing from Saravia’s public policy cycle insights, it assesses coastal management as a public policy, emphasizing variables and deficiencies in the process. The findings indicate fragmentation and regulatory shortcomings. To achieve integrated management, political cooperation is necessary for aligning interests and effective policy implementation across federal scales, contributing to sustainable coastal resource development in Brazil.

Tom Spencer, Janine Adams, Martin Le Tissier et al.

Although coasts are frequently seen as at the frontline of near-future environmental risk, there is more to the understanding of the future of coastal environments than a simple interaction between increasing hazards (particularly related to global sea level rise) and increasing exposure and vulnerability of coastal populations. The environment is both multi-hazard and regionally differentiated, and coastal populations, in what should be seen as a coupled social–ecological–physical system, are both affected by, and themselves modify, the impact of coastal dynamics. As the coupled dance between human decisions and coastal environmental change unfolds over the coming decades, transdisciplinary approaches will be required to come to better decisions on identifying and following sustainable coastal management pathways, including the promotion of innovative restoration activities. Inputs from indigenous knowledge systems and local communities will be particularly important as these stakeholders are crucial actors in the implementation of ecosystem-based mitigation and adaptation strategies.

Vilmar Leandro Dias Ferreira, Elizabeth Santos Pereira, Lucas Pluvie Souza de Mello et al.

As several researches indicate, since the 1950s one observed unprecedented warming of the atmosphere and oceans, resulting from greenhouse gas emissions and changes in land use and occupation, leading to sea level rise and impacts on coastal areas. In the municipality of Niterói—Rio de Janeiro, Brazil, where a large urban concentration in coastal areas is observed, a Climate Change Adaptation System was developed, through which mitigation and adaptation strategies are combined, in order to: reduce vulnerabilities; avoid losses and damages; build instruments to allow adaptation of natural, human, productive and infrastructure systems. In this context, this paper aims to measure possible impacts, in the biophysical and socioeconomic spheres, resulting from an eventual 0.50 m rise in mean sea level, which represents an optimistic scenario according to the National Oceanic and Atmospheric Administration. In contrast to similar studies, this work also considered daily and occasional water level variations, represented by the highest astronomical tide and the highest storm surge observed in the studied region. The following data were applied: digital elevation model, 2010 population census data, and real estate information. With the altimetry data, by means of GIS, the census sectors inserted in the affected areas were selected, to obtain data regarding population, number of households, and income. Specialized websites were applied to collect average property values. The simulations revealed that approximately 2950 households and more than 9000 residents could be directly affected, with losses that could exceed R$ 3.60 billion. The Oceanic Region is configured as the most exposed region, susceptible to losses of several ecosystems, economic losses in residential areas and possible destruction of urban infrastructure.

Francisco Flores-de-Santiago, Luis Valderrama-Landeros, Julen Villaseñor-Aguirre et al.

Although sandy islands in arid environments are vital protection sites for endemic species, they face constant natural and anthropogenic hazards, such as storm surge impacts and the occasional presence of off-road vehicles. Monitoring the sedimentary dune-beach displacement and balance is essential because sediment transportation usually does not depend on external sources, such as rivers. The latest generation of geomatic applications may be relevant to understanding coastal vulnerability due to their ability to acquire and process spatial data at unprecedented scales. The objective of this study was to analyze the sedimentary dynamics of a distinctive dune corridor on Altamura Island in the Gulf of California, Mexico. We compared three ultra-high spatial resolution digital surface models (DSMs) with geomorphic change detection (DoD), covering the 1150 m coastal stretch. We used light detection and ranging (LiDAR) data and analyzed changes in the coastline with the semi-automatic CoastSat tool. Although the orthomosaics and the DSM collected in April, June, and October 2021 show different conditions in sediment distribution along the beach-dune interface, depending on the direction and intensity of the wind, the two DoDs showed a constant sediment distribution balance of ~13 M m³ between April and June and June and October. LiDAR data along the 40-km length of the sandy island indicate that the entire island could present a similar sedimentation pattern between the dune and beach interface. The CoastSat data indicate a constant accretion of 125 m in the beach-ocean interface between 2015 and 2022. This study demonstrates that the sediment balance between the dune and the beach on arid sandy islands is vital for conserving their shoreline and all associated coastal ecosystems.

Yan Li, Amin Chabchoub

Wave transformation is an intrinsic dynamic process in coastal areas. An essential part of this process is the variation of water depth, which plays a dominant role in the propagation features of water waves, including a change in wave amplitude during shoaling and de-shoaling, breaking, celerity variation, refraction and diffraction processes. Fundamental theoretical studies have revolved around the development of analytical frameworks to accurately describe such shoaling processes and wave group hydrodynamics in the transition between deep- and shallow-water conditions since the 1970s. Very recent pioneering experimental studies in state-of-the-art water wave facilities provided proof of concept validations and improved understanding of the formed extreme waves’ physical characteristics and statistics in variable water depth. This review recaps the related most significant theoretical developments and groundbreaking experimental advances, which have particularly thrived over the last decade.