Communicating simulation outputs of mesoscale coastal evolution to specialist and non-specialist audiences

Coastal geomorphologists and engineers worldwide are increasingly facing the non-trivial challenge of visualising and communicating mesoscale modelling assumptions, uncertainties and outcomes to both coastal specialists and decision-makers. Visualisation of simulation outcomes is a non-trivial problem because the more abstract scientific visualisation techniques favoured by specialists for data exploration and hypothesis-testing are not always as successful at engaging decision-makers and planners. In this paper, we show how the risk of simulation model outcomes becoming disconnected from more realistic visualisations of model outcomes can be minimised by using the Coastal Modelling Environment (CoastalME). CoastalME is a modelling framework for coastal mesoscale morphological modelling that can achieve close linkages between the scientific model abstractions, in the form of lines, areas and volumes, and the 3D representation of topographic and bathymetric surfaces and shallow sub-surface sediment composition. We propose and illustrate through the study case of Happisburgh (eastern England, UK), a transparent methodology to merge the required variety of data types and formats into a 3D-thickness model that is used to initialise a simulation. We conclude by highlighting some of the barriers to the adoption of the methodology proposed

Beach Nourishment: A 21st Century Review

Long-term erosion is experienced by most of the coastlines worldwide, and it is usually attributed not only to sea level rise but also to the retention of sand in dams, the occupation of dry beaches by urbanized areas, the disturbance of the natural patterns of longshore drift, the mining of sand as building material for construction, and so on. Beach nourishment has evolved as the favored erosion-mitigation strategy in many areas of the world. The increasing number of people living on the coast, the safety of those people, and the high values of coastal property are all factors that have made beach nourishment a cost-effective strategy for managing erosion in many locations. However, a new scenario of sand scarcity and environmental care has arisen in recent decades. There have been a number of different and interesting cases of various aspects of beach nourishment in the last years. The purpose of this Special Issue has been to publish the different experiences and research related to this topic. After a careful review process, nine papers were included. Their thematic contributions include the use of field methods such as the use of remotely piloted aircraft systems (RPAS) or un-manned aerial vehicles (UAV) for faster and automated mapping of the coastal area or the acquisition of geomagnetic data in marine environments; the use of multi-approach methodologies to assess the interaction between coastal structures and beaches and in particular of submerged pipelines; the need to adopt a plan for the optimal use of limited resources of available sediment from a regional perspective and the assessment of the effectiveness of beach nourishments; the understanding of the role of submerged geological control of beach profiles together with the implementation of innovative beach nourishment strategies while facing the non-trivial challenge of visualizing and communicating mesoscale modeling assumptions, uncertainties and outcomes to both coastal specialists and decision makers; and the influence of sea-level rise and erosion on diminution of beach habitats

Beach Nourishment: A 21st Century Review

Erosion is experienced by most coastlines worldwide, and it is usually attributed not only to sea level rise but also to the retention of sand in dams, the occupation of dry beaches by urbanized areas, the mining of sand as a building material for construction, and so on. Beach nourishment has evolved as the favored erosion-mitigation strategy in many areas of the world. The increasing number of people living on the coast, the safety of those people, and the high values of coastal properties are all factors that have made beach nourishment a cost-effective strategy for managing erosion in many locations. However, a new scenario of sand scarcity and environmental care has arisen in recent decades. There have been many different and interesting cases of various aspects of beach nourishment in recent years. The purpose of this invited Special Issue is to publish the most exciting experience and research with respect to this topic. Thus, novel techniques for designing, executing, and controlling these kinds of works as well as different case studies and their monitoring results and conclusions have been included, in order to present an updated state of the art for marine scientists, researchers, and engineers

A new approach for incorporating sea-level rise in hybrid 2D/one-line shoreline models

Hybrid 2D/one-line shoreline models, which typically apply a finite volume approach to simulate sediment transport and the one-line theory to update the shoreline morphology, are being increasingly applied over meso timescales (10(1) to 10(2) years) to inform coastal management. The one-line theory assumption of a constant closure depth prevents these models from considering the effects of sea-level rise in the shoreline morphology update. Sea-level rise, an endogenous driving factor of meso timescale coastal behaviour, influences the closure depth through its effects on the wave climate. This paper presents a new hybrid 2D/one-line approach that enables a time-varying closure depth in response to annual variations in wave climate as a solution for mirroring the effects of sea-level rise on the coastal profile and associated shoreline evolution. This new hybrid approach is applied to hindcast meso timescale shoreline evolution in a sandy coastal system and compared against the traditional hybrid 2D/one-line approach. Results show that the traditional hybrid approach gives the most accurate predictions whereas the new hybrid approach overpredicts shoreline erosion. However, this overprediction is attributed to net closure depth overestimation. This attribution gives confidence that the shoreline response to the time-varying closure depth specified is within expectations since closure depth overestimation increases offshore sediment transport in shoreline models. Therefore, it is likely that enabling a time-varying closure depth in hybrid 2D/one-line models may improve meso timescale shoreline predictions under sea-level rise if closure depths can be accurately prescribed over time

On simulating shoreline evolution using a hybrid 2D/one-line model

Hybrid 2D/one-line shoreline models are becoming increasingly applied over the mesoscale (101–102 years; 101–102 km) to inform coastal management. These models typically apply the one-line theory to simulate changes in shoreline morphology based on littoral drift gradients calculated from a 2DH coupled wave, flow, and sediment transport model. However, the key boundary conditions needed to effectively apply hybrid 2D/one-line models and their applicability beyond simple planform morphologies are uncertain, which can potentially comprise coastal management decisions. To address these uncertainties, an extensive numerical modelling campaign is carried out to both assess the sensitivity and calibrate an advanced hybrid 2D/one-line model (MIKE21) against six variables in three different sandy coastal system morphologies: (a) a simple planform morphology with a gentle sloping profile, (b) a simple planform morphology with a steep sloping profile, and (c) a complex planform morphology. The six variables considered include nearshore discretisation, bathymetry, bed friction, sand grain diameter, sand porosity, sediment grading, and the weir coefficient of hard defence structures. Five key conclusions are derived from the sensitivity testing and calibration results. First, the optimal boundary conditions for modelling shoreline evolution vary according to coastal geomorphology and processes. Second, specifying boundary conditions within physically realistic ranges does not guarantee reliable shoreline evolution predictions. Third, nearshore discretisation should be treated as a typical calibration parameter as (a) the finest discretisation does not guarantee the most accurate predictions, and (b) defining a discretisation based on process length scales also does not guarantee reliable predictions. Fourth, hybrid 2D/one-line models are not valid for application in complex planform morphologies plausibly because of the one-line theory assumption of a spatially invariable closure depth. Fifth, hybrid 2D/one-line models have limited applicability in simple planform morphologies where the active beach profile is subject to direct human modification, plausibly due to the one-line theory assumption of a constant time-averaged coastal profile form. These findings provide key theoretical insights into the drivers of shoreline evolution in sandy coastal systems, which have practical implications for refining the continued application of shoreline evolution models

Modelling mesoscale evolution of managed sandy shorelines with particular reference to Caribbean small islands

Modelling the mesoscale (10 to 100 years and 10 to 100 km) evolution of managed sandy shorelines is becoming increasingly necessary to guide the management of sandy coastal systems. Models that simulate mesoscale shoreline evolution assume an equilibrium active coastal profile. An equilibrium active coastal profile implies a fixed closure depth, defined as the seaward extent of the active coastal area, and shore-parallel depth contours, which present two limitations. First, an inability to account for sea-level rise, which will likely change the closure depth and be endogenous in coastal evolution over meso timescales. Second, an inability to account for complex planform morphologies where the closure depth varies longshore and depth contours are non-parallel. Such morphologies characterise sandy coastal systems in many vulnerable Caribbean islands where shoreline evolution models are most needed to guide coastal management. Hence, this thesis aims to create a method that accounts for sea-level rise and complex planform morphologies in mesoscale shoreline evolution predictions. Using a managed sandy coastal system in New York, Puerto Rico, and Southern California as test sites, I first assess the sensitivity of two mesoscale shoreline evolution models, MIKE21 and the Bruun Rule, to identify the most essential boundary conditions influencing shoreline evolution predictions in different coastal morphologies. I use the results of this sensitivity study to inform the development and application of three shoreline evolution modelling approaches, which include introducing: (a) a time-varying closure depth in MIKE21 as a solution to incorporate sea-level rise effects in mesoscale shoreline evolution predictions; (b) a space-varying closure depth in MIKE21 as a solution to account for complex planform morphologies in shoreline evolution predictions; and (c) a time and space-varying closure depth in MIKE21 as a solution to incorporate the effects of both sea-level rise and complex planform morphologies in meso timescale shoreline evolution predictions. Model sensitivity results show that nearshore discretisation, bathymetry, tides, friction and sediment properties are the key boundary conditions that influence shoreline evolution predictions regardless of the underlying morphology. I find that the optimal specifications of these boundary conditions match coastal system features, both morphology and processes. Specifying a time-varying closure depth in MIKE21 is found to provide a better alternative to the Bruun Rule for simulating mesoscale shoreline evolution under relative sea-level rise. However, I find that a time-varying closure depth causes MIKE21 to overpredict erosion over meso timescales, attributed to mean closure depth overestimation. Hence, there is a chance that a time-varying closure depth may improve mesoscale shoreline evolution predictions if closure depth time series estimations can be accurately prescribed. Enabling a space-varying closure depth in MIKE21 is found to replicate observed shoreline change in the Puerto Rico test site’s complex planform morphology more realistically than existing modelling approaches. Lastly, allowing a time and space-varying closure depth in MIKE21 is found to provide theoretically plausible meso timescale shoreline evolution predictions under relative sea-level rise in the Puerto Rico test site’s complex planform morphology compared to current modelling approaches

Towards the “Perfect” Weather Warning

This book is about making weather warnings more effective in saving lives, property, infrastructure and livelihoods, but the underlying theme of the book is partnership. The book represents the warning process as a pathway linking observations to weather forecasts to hazard forecasts to socio-economic impact forecasts to warning messages to the protective decision, via a set of five bridges that cross the divides between the relevant organisations and areas of expertise. Each bridge represents the communication, translation and interpretation of information as it passes from one area of expertise to another and ultimately to the decision maker, who may be a professional or a member of the public. The authors explore the partnerships upon which each bridge is built, assess the expertise and skills that each partner brings and the challenges of communication between them, and discuss the structures and methods of working that build effective partnerships. The book is ordered according to the “first mile” paradigm in which the decision maker comes first, and then the production chain through the warning and forecast to the observations is considered second. This approach emphasizes the importance of co-design and co-production throughout the warning process. The book is targeted at professionals and trainee professionals with a role in the warning chain, i.e. in weather services, emergency management agencies, disaster risk reduction agencies, risk management sections of infrastructure agencies. This is an open access book

Sediment Thickness Model of Andalusia’s Nearshore and Coastal Inland Topography

This study represents the first attempt to map the sediment thickness spatial distribution along the Andalusian coastal zone by integrating various publicly available datasets. While prior studies have presented bedform- and sediment-type syntheses, none have attempted to quantify sediment thickness at the scale and resolution performed in this study. The study area has been divided into 18 physiographic zones, and we have used BGS Groundhog Desktop v2.6 software for 3D modeling and sediment thickness model calculations. We present here the modeling workflow, model results, and the challenges that we have encountered, including discrepancies in geological maps, difficulty managing data input for grain size/consolidation, and the need for additional geological information. We have compared the modeled sediment fractions of the unconsolidated material with 4194 seabed samples distributed along the study area and found that the differences between the modeled versus the sampled emphasized the importance of incorporating river contributions, particularly from the Guadalquivir River, into the model for more accurate results. The model intermediate and final outputs and the software routines used to query the sediment thickness model are provided as publicly accessible datasets and tools. The modeled sediment thickness could contribute to making quantitative predictions of morphological change at a scale that is relevant to longer-term strategic coastal management in Andalusia. The methodology and tools used for this study are transferable to any study area

Transitions in modes of coastal adaptation: addressing blight, engagement and sustainability

Coastal defences have long provided protection from erosion and flooding to cities, towns and villages. In many parts of the world, continued defence is being questioned due to both environmental, sustainability and economic considerations. This is exemplified in England and Wales, where strategic Shoreline Management Plans envisage realignment of many protected coasts, often with low population densities, over the coming decades. The policy transition from protection to realignment is often resisted by affected communities and can have high political costs. Whilst some preparations for such transitions have been made, the communities affected are often not fully aware of the implications of policy change, and this brings the potential for blight. In this paper, we investigate the challenges of implementing transitions in coastal policy within England and Wales. The analysis is based on data obtained from three workshops held in 2019 that were attended by council members, engineers, planners, scientists and other relevant professionals. Five conditions are found to promote contention: (i) policy actors with competing priorities and different decision making time frames (immediate to decadal to a century); (ii) divergence between regulations and ad hoc political decisions (e.g. in relation to the demand for new housing); (iii) limited or non-existent funding to support policy transition; (iv) community expectation that protection is forever; and (v) a disconnection between people and ongoing coastal change. Our research indicates that transitions can be better supported through: (1) integrated multi-scalar preparedness for coastal change; (2) an accessible evidence base and future vision to nurture political confidence in adaptation; and (3) defined, time-bound and accessible diverse funding streams to achieve transitions. Critically, these generic actions need to be embedded within the local political and planning system to facilitate transition to more sustainable coasts and their communities

PICES Press, Vol. 22, No. 2, Summer 2014

FUTURE and the FUTURE Open Science Meeting— The future of FUTURE (pp. 1-2); 2014 Inter-sessional Science Board Meeting: A note (pp. 3-5); More attractive science ecosystem design for FUTURE and beyond: A personal view (pp. 6-8); OSM Session on “Identifying multiple pressures and system responses in North Pacific marine ecosystems” (pp. 9-10); OSM Session on “Regional climate modeling in the North Pacific” (pp. 11-11); OSM Session on “Challenges in communicating science and engaging the public” (pp. 12-15); OSM Sessions on “Ecosystem status, trends, and forecasts” and “Ecosystem resilience and vulnerability” (pp. 16-17); OSM Session on “Strategies for ecosystem management in a changing climate” (pp. 18-19); OSM Workshop on “Top predators as indicators of climate change” (pp. 20-23); OSM Workshop on “Bridging the divide between models and decision-making” (pp. 24-26); OSM Workshop on “Climate change and ecosystem-based management of living marine resources” (pp. 27-28); OSM Workshop on an “Ecosystem projection model inter-comparison and assessment of climate change impacts on global fish and fisheries” (29-34); ICES Symposium on the “Ecological basis of risk analysis for marine ecosystems” (pp. 35-38); Human dimensions in the Russian Federation (pp. 39-42); Microbial Culture Collection at the National Institute for Environmental Studies, Tsukuba, Japan (pp. 43-45); The Bering Sea: Current status and recent trends (pp. 46-48); The state of the western North Pacific in the second half of 2013 (pp. 49-50); Unusual warming in the Gulf of Alaska (pp. 51-52); Obituary – Dr. Toshiro Saino (pp. 53-55); Program of topic sessions and workshops at PICES-2014 (pp. 56-56); 3rd International Symposium on “Effects of climate change on the world’s oceans” (pp. 57-57); PICES Interns (pp. 58-58