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There is conflicting evidence on whether people, particularly those with preexisting mental health problems, have worse mental health during and after extended solitary confinement (SC) stays. Using administrative data on 843 men, we examined within-person changes in mental health functioning and service use surrounding long-term stays in SC in Florida correctional facilities. During these stays, service use increased, psychological functioning improved, and mental health crises declined. The former two associations persisted during step-down placements in lower levels of restrictive housing and during the month following restrictive housing stays. The same associations were observed among men with and without serious mental illnesses, though they were more muted among the former group. The increased provision of treatment might prevent mental health problems from developing or worsening among those held in long-term SC and might even improve psychological functioning relative to when the same people are in general population housing.

The punitive era in the United States and other countries has included reliance on long-term restrictive housing (LTRH)—consisting of solitary confinement with few privileges—as a means of managing violent and disruptive individuals in prison. We examine how work in such housing may influence how personnel, including officers and staff, view individuals in prison and assess two hypotheses. First, those who work in LTRH will be more likely to hold a dehumanized view of these individuals. Second, the theoretical mechanisms through which such a view may arise involve brutalization, organizational context and culture, role conflict and distancing, and empathy fatigue. We assess these hypotheses using a mixed-methods study, analyzing data from a large-scale prison personnel survey ( n = 9,656) and qualitative focus group and interview data ( n = 144). Implications of the study’s findings for theory and research on restrictive housing, corrections, and the punitive era are discussed.

Wave overtopping of sea defences poses a hazard to people and infrastructure. Rising sea levels and limited resources mean accurate prediction tools are needed to deliver cost-effective shoreline management plans. A dearth of in-situ data means that the numerical tools used for flood forecasting and coastal scheme design are based largely on data from idealised flume studies, and the resulting overtopping predictions may have orders of magnitude uncertainty for complicated structures and some environmental conditions. Furthermore, such studies usually only provide data on the total volume of overtopping water, and no data on the speed of the water. Here we present WireWall, an array of capacitance-based sensors which measure the speed and volume of overtopping water on a wave-by-wave basis. We describe the successful validation of WireWall against traditional flume methods and present results from the first trial deployments at a sea wall in the UK. WireWall results are also compared with numerical predictions based on EurOtop guidance. WireWall technology offers an approach for reliable acquisition of the data needed to develop resilient coastal protections schemes.

A signature feature of the get-tough era in American corrections has been the proliferation of restrictive housing (RH). Although sometimes equated with solitary confinement, this housing encompasses a variety of distinct forms of incarceration. They are unified by an emphasis on restricted movement and privileges—yet vary in their design and uses. Despite that fact, little is known about the prevalence of different forms of housing. To address this research gap, we use a case study of Florida policy and administrative records data to illuminate the variety of RH types and the varying prevalence of each. We then discuss the implications of the findings for the study of RH uses and impacts and for policy.

The present study examines the relationship between legal status and prisoner misconduct by comparing official disciplinary infraction reports between documented, undocumented, and native-born inmates. We also examine the extent to which such effects vary across different types (i.e., criminal and non-criminal) of reported infractions. Using data from the Florida Department of Corrections, the results reveal that undocumented foreigners have a higher likelihood and a higher frequency of any misconduct and criminal misconduct as well as a higher frequency of non-criminal misconduct than the other two groups, while no such differences are found between documented and native-born prisoners. Our research underscores the salient role of legal status in predicting the in-prison behaviors of foreign-born inmates.

Following the 1st International Workshop on Waves, Storm Surges and Coastal Hazards, which incorporated the 15th session of the long-standing the International Workshop on Wave Hindcasting and Forecasting, in September 2017 in Liverpool, United Kingdom, a topical collection has appeared in recent issues of Ocean Dynamics. Here, we give a brief overview of the 15 papers published in this topical collection as well as an overview of the widening scope of the conference in recent years. The continuing trend towards closer integration between the wave and ocean modeling communities is reflected in this workshop, culminating in the renaming of the workshop, while maintaining the connection with the three-decade long history of the wave workshop. This is also seen in this topical collection, with several papers exploring wave-generated storm surge, wave-tide contributions to coastal flooding, forcing a global ocean model with fluxes from a wave model and interaction between surface waves and sea ice.

Despite concerns and debates about the policy of using extended solitary confinement for managing individuals deemed to be too violent or disruptive to be controlled any other way—for the broader g...

Coastal communities and infrastructure need protection from flooding and wave overtopping events. Assessment of hazard prediction methods, used in sea defence design, defence performance inspections and forecasting services, requires observations at the land-sea interface but these are rarely collected. Here we show how a database of hindcast overtopping events, and the conditions that cause them, can be built using qualitative overtopping information obtained from social media. We develop a database for a case study site at Crosby in the Northwest of England, use it to test the standard methods applied in operational flood forecasting services and new defence design, and suggest improvements to these methods. This novel approach will become increasingly important to deliver long-term, cost-effective coastal management solutions as sea-levels rise and coastal populations grow. At sites with limited, or no, monitoring or forecasting services, this approach, especially if combined with citizen science initiatives, could underpin the development of simplified early warning systems.

Estuarine salt intrusion greatly threatens freshwater supply in surrounding lands. Physical barriers, which reduce the estuary length (L), are widely constructed to control salt intrusion. Yet, the role of L in salt intrusion remains unknown. Using a process-based, idealized, semi-analytical three-dimensional model, we systematically investigate for the first time this unknown for tide-dominated, periodically weakly stratified estuaries. Results show decreasing L significantly reduces salinities for short estuaries (L < Lw/4, with Lw the dominant tidal wavelength), but not for long estuaries. Tidal pumping remains a key salt importer in most estuaries, regardless of L. However, substantial decreases in L relative to Lw/4 can change the dominant landward salt importer from tidal pumping to horizontal diffusion. The latter, together with gravitational circulation, weakens responses of salt intrusion to changes in tidal and river forcing in short estuaries. This study highlights the importance of considering L to understanding and mitigating salt intrusion.

A total of 3719 articles appearing in five key generalist forensic psychology journals (n = 1374) and six more specialist targeted forensically related journals (n = 2345) between 2015 and 2020 were subject to a bibliometric analysis to reveal trends in research topics, populations studied, jurisdiction, and research methods employed. Research on offenders dominated and over half of all the papers were located in North American jurisdictions. About a third of papers made explicit reference to diversity and two thirds of research designs employed quantitative methodologies. The discussion features comments on changing trends over time from forensic psychology’s initial narrow focus on witness testimony to its current broader remit, and the different coverage between targeted and generalist journals. The conclusion offers some reflections for future forensic psychology.

Asymmetric tidal turbulence (ATT) strongly influences estuarine health and functioning. However, its impact on the three-dimensional estuarine dynamics and the feedback of water motion and salinity distribution on ATT remain poorly understood, especially for short estuaries (estuarine length ≪ tidal wavelength). This study systematically investigates the abovementioned interactions in a short estuary for the first time, considering periodically weakly stratified conditions. This is done by developing a three-dimensional semi-analytical model (combining perturbation method with finite element method) that allows a dissection of the contributions of different processes to ATT, estuarine circulation, and salt transport. The generation of ATT is dominated by (i) strain-induced periodic stratification and (ii) asymmetric bottom-shear-generated turbulence, and their contributions to ATT are different both in amplitude and phase. The magnitude of the residual circulation related to ATT and the eddy viscosity–shear covariance (ESCO) is about half of that of the gravitational circulation (GC) and shows a “reversed” pattern as compared to GC. ATT generated by strain-induced periodic stratification contributes to an ESCO circulation with a spatial structure similar to GC. This circulation reduces the longitudinal salinity gradients and thus weakens GC. Contrastingly, the ESCO circulation due to asymmetric bottom-shear-generated turbulence shows patterns opposite to GC and acts to enhance GC. Concerning the salinity dynamics at steady state, GC and tidal pumping are equally important to salt import, whereas ESCO circulation yields a significant seaward salt transport. These findings highlight the importance of identifying the sources of ATT to understand its impact on estuarine circulation and salt distribution.

There is mixed evidence on whether incarcerated persons with mental illnesses have increased odds of being placed in solitary confinement. This study answered this question using a large system-wid...

In recent decades, long-term solitary confinement has become a mainstay of prison systems. Critiques and research of this confinement typically have focused on its potential harms. Few studies have examined the range of harms to those placed in it; fewer still have examined solitary confinement’s potential benefits or sought insight from those who work with them. Guided by Sykes’ deprivation theory, we draw on focus groups and interviews with 144 correctional personnel to examine their perceptions of incarcerated individuals’ experiences with, and responses to, deprivations of solitary confinement. We show that staff view the pains of imprisonment as potentially increasing or decreasing in solitary confinement and that they view incarcerated persons as adapting to such confinement in different ways.

Wave overtopping formulae, which often underlie coastal hazard early warning systems, are typically parameterised using wave conditions at the toe of the structure. For very shallow conditions where significant wave breaking occurs over the foreshore, this usually requires computationally-demanding numerical models—and practitioners skilled in their application—to accurately transform offshore waves to the structure toe. An additional concern is that overtopping formulae are scarcely validated in the field due to the very limited availability of in-situ overtopping data obtained at actual structures. Here, we validate a set of deep-water-parameter-based formulae for mean overtopping discharge (q) at smooth slopes, which remove the need for nearshore measurements or additional numerical modelling but require that a single representative foreshore slope angle (m) be defined. The validation is carried out against field data gathered at Crosby (UK) using two novel approaches: i) a new overtopping measurement system called “WireWall”; and ii) crowd-sourced data in the form of overtopping images obtained from a community Facebook page (social media). A method is introduced to define m for irregular bathymetries, based on the location where the local water depth is equal to the offshore significant wave height. The overtopping formulae proved accurate—with estimates of q being within a factor of 4 of observations—when compared to both 1-h averaged and 15-min averaged overtopping data, suggesting that the approach can be used for both design and assessment and now-casting hazard information. Finally, hindcasts made using the newly validated formulae for the events reported by the community indicate that q can exceed 10 l/s/m under yearly winter conditions, posing a serious hazard to pedestrians. This highlights the pressing need to update the current hazard warning system at Crosby, which estimates q to be a factor of 3 lower than the deep-water-parameter-based approach, on average.

As part of the rise of “get tough” punishment in recent decades, prison systems increasingly have relied on solitary confinement and what many contemporary accounts have termed “restrictive housing.” The latter includes an emphasis on some form of isolation and restrictions on privileges. Use of solitary-like confinement has engendered considerable debate because of differing views about whether it is moral or effective and whether it harms inmates. Despite this debate and the ubiquity of solitary-like confinement, there is much that remains unknown about its uses or effects. A central reason stems from inconsistent operationalizations of such housing in research and policy. This situation creates problems in generalizing the results of studies to diverse settings and populations. The goals of this article are to highlight these points and to advance scholarship and policy debates by presenting a conceptual framework for guiding and assessing research on restrictive housing.

Over the past decade, a growing number of scholars have explored the effect of prison visitation on individuals’ post-release behavior. Findings from this work generally indicate a link between in-prison visits and reductions in recidivism. Yet whether the effect of visitation on recidivism operates similarly across race and ethnicity remains largely unexplored. In the current investigation, we draw on data from the Florida prison system, to examine associations between visitation and recidivism, including whether the effect of visitation is similar across race and ethnic groups. Our findings contribute to research and theorizing on prison visitation by further unpacking the visitation-recidivism link. We conclude by discussing the broader policy implications of our findings.

Combination of uncertainties in water level and wave height predictions for extreme storms can result in unacceptable levels of error, rendering flood hazard assessment frameworks less useful. A 2D inundation model, LISFLOOD-FP, was used to quantify sensitivity of flooding to uncertainty in coastal hazard conditions and method used to force the coastal boundary of the model. It is shown that flood inundation is more sensitive to small changes in coastal hazard conditions due to the setup of the regional model, than the approach used to apply these conditions as boundary forcing. Once the threshold for flooding is exceeded, a few centimetres increase in combined water level and wave height increases both the inundation and consequent damage costs. Improved quantification of uncertainty in inundation assessments can aid long-term coastal flood hazard mitigation and adaptation strategies, to increase confidence in knowledge of how coastlines will respond to future changes in sea-level.

There is a good understanding of past and present coastal processes as a result of coastal monitoring programmes within the UK. However, one of the key challenges for coastal managers in the face of climate change is future coastal change and vulnerability of infrastructure and communities to flooding. Drawing on a vulnerability-led and decision-centric framework (VL-DC) a Decision Support Tool (DST) is developed which, combines new observations and modelling to explore the future vulnerability to sea-level rise and storms for nuclear energy sites in Britain. The combination of these numerical projections within the DST and a Real Options Analysis (ROA) delivers essential support for: (i) improved response to extreme events and (ii) a strategy that builds climate change resilience.

Long-term coastal management of beach/dune systems requires the definition and assessment of storm events. This study presents a framework using statistical analyses and numerical modelling (XBeach) to characterize storm events and investigate their impact on beach/dune erosion. The method is developed using exemplary data from Formby Point on the Sefton coast (UK), which has a complex beach morphology and frontal dunes. Relevant storm events are classified by a versatile univariate response function taking into account both nearshore water levels and offshore significant wave heights (Hs). It is shown that compared to the established storm classification (Hs ≥ 2.5 m) 35% more storm events that are relevant for beach/dune erosion are identified. Also the events exceed critical conditions for longer durations, and cause greater erosion impact (12%) along the beach/dune profile. The proposed classification of storm events thus captures relevant events for the storm erosion and can inform coastal management strategies. This framework is widely applicable to other beach/dune systems. © 2021 The Authors

Resilient coastal protection requires adaptive management strategies that build with nature to maintain long-term sustainability. With increasing pressures on shorelines from urbanisation, industrial growth, sea-level rise and changing storm climates soft approaches to coastal management are implemented to support natural habitats and maintain healthy coastal ecosystems. The impact of a beach mega-nourishment along a frontage of interactive natural and engineered systems that incorporate soft and hard defences is explored. A coastal evolution model is applied to simulate the impact of different hypothetical mega-nourishment interventions to assess their impacts’ over 3 shoreline management planning epochs: present-day (0–20 years), medium-term (20–50 years) and long-term (50–100 years). The impacts of the smaller interventions when appropriately positioned are found to be as effective as larger schemes, thus making them more cost-effective for present-day management. Over time the benefit from larger interventions becomes more noticeable, with multi-location schemes requiring a smaller initial nourishment to achieve at least the same benefit as that of a single-location scheme. While the longer-term impact of larger schemes reduces erosion across a frontage the short-term impact down drift of the scheme can lead to an increase in erosion as the natural sediment drift becomes interrupted. This research presents a transferable modelling tool to assess the impact of nourishment schemes for a variety of sedimentary shorelines and highlights both the positive and negative impact of beach mega-nourishment.

Storm propagation speed (SPS) can noticeably impact coastal floods around semi-closed basins influenced by extratropical offshore storms. As a case study, the SPS impact on potential flood hazards due to extreme water levels along the UK east coast was studied using a numerical shelf sea model (FVCOM). The storm Xaver, which caused the largest North Sea surge over the past 60 years, was studied as a base scenario. Halving/doubling the SPS results in a smaller surge and a longer/shorter surge duration. Hence, the largest peak water level was found at actual speed, while the largest potential flood hazard occurred at half speed. Tide–surge interaction tends to reduce the M2 tide along the coast and advance its propagation for all SPS. A three-dimensional semi-analytical model, including a time-periodic wind forcing, was used to investigate the dominant mechanisms behind the surge dynamics, where wind duration is directly related to the SPS. Long wind durations correspond to small SPS, and vice versa. The semi-analytical model was applied to the North Sea. The model reproduces the spatial features of the North Sea surge and its dependence on SPS, confirming the surge induced by offshore storms is primarily associated with wind set-up. Model results suggest the SPS of Xaver is likely to have contributed greatly to the occurrence of the largest North Sea surge due to wind-generated resonance. The impact of the SPS on the surge and tide–surge interaction are of great importance to coastal flood hazard assessment.

Poorly constrained uncertainties limit the prediction of medium-term to long-term regional sediment budgets and morphological change, and thus hinder coastal management decision-making. We present a multi-disciplinary approach that aims to address this challenge and is implemented in the BLUEcoast project. The approach brings together scientists and coastal stakeholders across a range of scientific disciplines. Quantifying all processes at all scales is not feasible and our approach uses targeted representative case studies, which are carefully selected to allow subsequent upscaling and ensure transferability. We illustrate this approach with specific examples from the BLUEcoast consortium.

Benthic sediments in continental shelf seas control a variety of biogeochemical processes, yet their composition, especially that of fine sediment, remains difficult to predict. Mechanisms for mud or fine sediment deposition and retention are not fully understood. Using sediment data and a hydrodynamic model of the Northwest European shelf seas, a relationship is shown to exist between fine benthic sediment composition and regions of cyclonic tidal current rotation. The reduced thickness of cyclonic tidal benthic boundary layers compared with the anticyclonic case promotes deposition of fine sediment and trapping of resuspended material. Adding the effects of the benthic boundary layer thickness, as influenced by ellipticity or not, sheds some light on the limitations of approaches only focusing on bed shear stress and sediment pathways to predict the location of mud deposits. A tidal boundary layer predictor that includes ellipticity alongside tidal current magnitude and depth was shown to spatially agree with maps of mud deposits.

A region of freshwater influence (ROFI) under hypertidal conditions is used to demonstrate inherent problems for nested operational modelling systems. Such problems can impact the accurate simulation of freshwater export within shelf seas, so must be considered in coastal ocean modelling studies. In Liverpool Bay (our UK study site), freshwater inflow from 3 large estuaries forms a coastal front that moves in response to tides and winds. The cyclic occurrence of stratification and remixing is important for the biogeochemical cycles, as nutrient and pollutant loaded freshwater is introduced into the coastal system. Validation methods, using coastal observations from fixed moorings and cruise transects, are used to assess the simulation of the ROFI, through improved spatial structure and temporal variability of the front, as guidance for best practise model setup. A structured modelling system using a 180 m grid nested within a 1.8 km grid demonstrates how compensation for error at the coarser resolution can have an adverse impact on the nested, high resolution application. Using 2008, a year of typical calm and stormy periods with variable river influence, the sensitivities of the ROFI dynamics to initial and boundary conditions are investigated. It is shown that accurate representation of the initial water column structure is important at the regional scale and that the boundary conditions are most important at the coastal scale. Although increased grid resolution captures the frontal structure, the accuracy in frontal position is determined by the offshore boundary conditions and therefore the accuracy of the coarser regional model.

Brown, J.M.; Prime, T.; Phelps, J.J.C.; Barkwith, A.; Hurst, M.D.; Ellis, M.A.; Masselink, G., and Plater, A.J., 2016. Spatio-temporal Variability in the Tipping Points of Coastal Defense. 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. 1042 - 1046. Coconut Creek (Florida), ISSN 0749-0208. To enable effective adaptive management, early warning of when a ‘tipping point’ within a system's defense may occur is vital. A tipping point is a critical threshold at which the state of a system is altered, perhaps irreversibly. After the extremity of the UK's 2013/2014 winter, many coastal systems have undergone a change in state. For example, the conversion of a sandy beach into a rocky platform or an increase/decrease in flood hazard due to a defense breach or new intervention. Coastal monitoring networks around the UK have enabled data collection...

Storms across the globe and their associated consequences in coastal zones (flooding and erosion), combined with the long-term geomorphic evolution of our coastlines, are a threat to life and assets, both socioeconomic and environmental. In a changing climate, with a rising global sea level, potentially changing patterns in storm tracks and storminess, and rising population density and pressures on the coastal zone, the future risk of coastal storm impacts is likely to increase. Coastal managers and policy makers therefore need to make effective and timely decisions on the use of resources for the immediate and longer Research focused on "monitoring and modelling to guide coastal adaptation to extreme storm events in a changing climate" is becoming more common; its goal is to provide science-based decision support for effective adaptation to the consequences of storm impacts, both now and under future climate scenarios at the coast. The growing transfer of information between the science community and end-users is enabling leading research to have a greater impact on the socioeconomic resilience of coastal communities. This special issue covers recent research activities relating to coastal hazard mapping in response to extreme events, economic impacts of long-term change, coastal processes influencing management decisions and the development of online decision support tools.

This paper provides a sensitivity analysis around how characterizing sandy, intertidal foreshore evolution in XBeach-X impacts on wave runup and morphological change of a vulnerable, composite gravel beach. The study is motivated by a need for confidence in storm-impact modeling outputs to inform coastal management policy for composite beaches worldwide. First, the model is run with the sandy settings applied to capture changes in the intertidal foreshore, with the gravel barrier assigned as a non-erodible surface. Model runs were then repeated with the gravel settings applied to obtain wave runup and erosion of the barrier crest, updating the intertidal foreshore from the previous model outputs every 5, 10 and 15 min, and comparing this with a temporally static foreshore. Results show that the scenario with no foreshore evolution led to the highest wave runup and barrier erosion. The applied foreshore evolution setting update is shown to be a large control on the distribution of freeboard values indicative of overwash hazard and barrier erosion by causing an increase (with 5 min foreshore updates applied) or a decrease (with no applied foreshore updating) in the Iribarren number. Therefore, the sandy, intertidal component should not be neglected in gravel barrier modeling applications given the risk of over- or under-predicting the wave runup and barrier erosion.

A pressing problem facing coastal decision makers is the conversion of "high-level" but plausible climate change assessments into an effective basis for climate change adaptation at the local scale. Here, we describe a web-based, geospatial decision support tool (DST) that provides an assessment of the potential flood risk for populated coastal lowlands arising from future sea-level rise, coastal storms, and high river flows. This DST has been developed to support operational and strategic decision making by enabling the user to explore the flood hazard from extreme events, changes in the extent of the flood-prone areas with sea-level rise, and thresholds of sea-level rise where current policy and resource options are no longer viable. The DST is built in an open-source GIS that uses freely available geospatial data. Flood risk assessments from a combination of LISFLOOD-FP and SWAB (Shallow Water And Boussinesq) models are embedded within the tool; the user interface enables interrogation of different combinations of coastal and river events under rising-sea-level scenarios. Users can readily vary the input parameters (sea level, storms, wave height and river flow) relative to the present-day topography and infrastructure to identify combinations where significant regime shifts or "tipping points" occur. Two case studies demonstrate the attributes of the DST with respect to the wider coastal community and the UK energy sector. Examples report on the assets at risk and illustrate the extent of flooding in relation to infrastructure access. This informs an economic assessment of potential losses due to climate change and thus provides local authorities and energy operators with essential information on the feasibility of investment for building resilience into vulnerable components of their area of responsibility.

The coastal impacts of climate change, including flooding and erosion due to storms and sea-level rise, and the possible adaptation responses have been studied using very different approaches; from very detailed site-specific, process-based investigations and interventions to global macroeconomic assessments of coastal zone vulnerability. This paper presents a flood defense real option analysis methodology that values potential investment decisions made in the building and maintaining of flood defenses around electricity infrastructure at local spatial scales for a large region. Real option analysis embraces uncertainty in future climate conditions and flexibility in the management of investment projects to produce a more precise optimal outcome than attained with traditional discount cash flow analysis alone. The method uses high-level analysis from flood inundation models to assess the cost of flooding for energy infrastructure at the present-day up to the highest plausible sea-level rise for the UK in 2100 known as the H++ scenario, which projects a sea-level rise of 1.8 m. These costs feed into a real option valuation model able to identify which energy infrastructure will benefit from investment, and when. This northwest UK study identifies two infrastructure sites that, today, would benefit from flood defence investment over discount cash flow analysis, increasing to an additional 14 in 2050. Using this method has identified 46 sites that would benefit from deferring flood defence investment now, reducing to 35 sites in 2050. This method of project valuation can be applied to any feature within the floodplain, e.g. infrastructure or residential housing, making it an adaptable and useful tool in identifying vulnerable features that require investment to ensure they stay resilient to extreme flood events in the future. This work is the result of an inter-disciplinary collaboration between hydrodynamic modelling, flood risk assessment and economics. The outputs of which are ideal to be fed into a decision-support tool, allowing stakeholders to interrogate and disseminate information about the spatial locations they are interested in.

Astronomical high tides and meteorological storm surges present a combined flood hazard to communities and infrastructure. There is a need to incorporate the impact of tide-surge interaction and the spatial and temporal variability of the combined flood hazard in flood risk assessments, especially in hyper-tidal estuaries where the consequences of tide and storm surge concurrence can be catastrophic. Delft3D-FLOW is used to assess up-estuary variability in extreme water levels for a range of historical events of different severity within the Severn Estuary, southwest England as an example. The influence of the following on flood hazard is investigated: (i) event severity, (ii) timing of the peak of a storm surge relative to tidal high water and (iii) the temporal distribution of the storm surge component (here in termed the surge skewness). Results show when modelling a local area event severity is most important control on flood hazard. Tide-surge concurrence increases flood hazard throughout the estuary. Positive surge skewness can result in a greater variability of extreme water levels and residual surge component, the effects of which are magnified up-estuary by estuarine geometry to exacerbate flood hazard. The concepts and methodology shown here can be applied to other estuaries worldwide.

Two-dimensional numerical simulations were used to investigate the impacts of storm clustering on the beach/dune evolution of the Sefton coast, Liverpool Bay, UK. A storm cluster consisting of a series of closely spaced seven events was identified using observed wave and surge data during the 2013/2014 winter period. First event in this cluster is regarded as exceptionally intense and the occurrence of seven storms within a very short time period, is unique. The XBeach coastal area model was used to simulate beach change from 1) the storm sequence (Clustered events) and 2) the same storms considering them as isolated events. Offshore metadata was transformed to the nearshore area using the Delft3D and SWAN models. Resulting evolution was first compared with the available post-storm profiles measured at a number of locations along the Sefton coast. Analysis of the Clustered and Isolated simulations showed the effect of clustering on the Sefton beach/dune system when compared to the impact of isolated events occurring on a fully recovered beach system. Morphological change occurred during each storm in the Cluster was influenced by the preceding storm(s), such that the evolution is not proportional to the storm power of the event, as it would be for Isolated events. Both storm cases resulted in heavy erosion at Formby Point (i.e. central of the Sefton coast) and accretion in the north and south. The Cluster prevented system recovery with the area of erosion continually extending south along the coast compared with that in Isolated events. The initial storm within the Cluster caused large bed level changes in the nearshore ridge-runnel system, enabling the subsequent storms to penetrate further south. The local convex geometry of the Sefton coast is found to have more influence on the beach/dune morphodynamics than the clustering effect. This study enhances the understanding beach/dune response to storm clusters, to interpret observed morphological changes and to develop tools for sustainable coastal management particularly in the Sefton coast and generally in similar systems worldwide.