Coastal Storm Surge Research Articles

The Roman fish tanks of the Western Mediterranean basin as potential scenarios for research on sea-level changes

PurposeThis paper analyses Roman fish tanks, which have functional elements that could be used to research on palaeo-sea-levels. Thus, the conditions of 37 installations in the Western Mediterranean basin are reviewed to identify those that have the best environmental and constructive conditions to be analyzed.Design/methodology/approachThe methodology was largely based on the review of existing scientific bibliography dealing with sea-level variations from studies on historical constructions, existing historical documentation on Roman fish tanks on the Mediterranean coast, as well as the fieldwork carried out in fish tanks on the Mediterranean coasts.FindingsThe Roman coastal fish tanks located in the shoreline of the Western Mediterranean Sea have turned out to be an excellent indicator of sea-level changes. Nevertheless, current coastal retreat, erosion and storm surges are posing significant threats to their preservation, and they could be considered as a heritage at risk of disappearance. Moreover, variations in the tectonic behaviour of the different coastal sectors make it challenging to select these facilities as an indicator of the sea level.Originality/valueThe analysis of Late Holocene sea-level changes and palaeoenvironments from archaeological and biological evidences, although not without difficulties, is very convenient because it provides very precise data that cannot be obtained with other absolute dating methods. This approach is increasingly gaining popularity with researchers and is very innovative in its method of combining the results of several scientific disciplines.

Understanding the Effects of Wind Intensity, Forward Speed, Pressure and Track on Generation and Propagation of Hurricane Irma Surges around Florida

In this study, it is demonstrated that hurricane wind intensity, forward speed, pressure, and track play an important role on the generation and propagation of coastal storm surges. Hurricane Irma, which heavily impacted the entire Florida peninsula in 2017, is used to study the storm surge sensitivity to varying storm characteristics. Results show that the west coast experiences a negative surge due to offshore wind of the approaching storm, but the positive surge returns after the hurricane eye passes over a location and wind became onshore. In the west coast peak, surges are intensified by an increase in onshore wind intensity and forward speed. In the Florida Keys, peak surges are intensified by an increase in wind intensity, a decrease in forward speed and a decrease in pressure. In southeast and east Florida, peak surges are intensified by decrease in pressure, although overall surges are less significant as the water can slide along the coastline. In the recessed coastline of Georgia-Carolinas, maximum surge is elevated by an increase in onshore wind intensity. Shifting the track westward increases peak surges on the west coast, while shifting the track eastward increases peak surge on the east coast. The results demonstrate a new understanding about the sensitivity of surge to varying parametric conditions and the importance of considering changes in the coastline orientation in storm surge predictions.

Evaluating storm surge predictability on subseasonal timescales for flood forecasting applications: A case study for Hurricane Isabel and Katrina

Coastal flooding operational forecasting in the US is limited to short-range temporal scales (3–7 days), which limits the response time for emergency preparation and planning. The sub-seasonal prediction project (SubX), which produces weather forecasts with a lead time of up to four weeks, provides an opportunity to assess the potential for creating probabilistic flood forecasts with longer lead times. Using the ADCIRC hydrodynamic model for coastal storm surge, two major hurricanes, Isabel (2003) and Katrina (2005), were used as case studies to test coastal flood predictions induced by wind and pressure fields generated from five global weather models within SubX. The storm surges simulations are forced by Sea Level Pressure (SLP) and 10 m winds fields from SubX models for a lead-time of up to 30 days before storm landfall. The subseasonal surge forecasts are evaluated temporally and spatially at 1–4 weeks lead-time against the NOAA tide gages observations and a verification dataset derived by forcing the storm surge model with wind and pressure fields from the NCEP-Reanalysis. The results are evaluated in terms of lead-time and forecast skill metrics. The storm surge forecast skill is measured using the mean square error skill score (MSESS) relative to the verification dataset and an approximate of the climatology. A skill score greater than 0.55 is considered here useful for flood forecasting. The multi-model ensemble (MME) mean surge forecasts driven by several members of SubX models demonstrate skill greater than 0.55 up to a 4-day and 10-day lead for Katrina and Isabel, respectively. A sharper decrease in MSESS was noted from week 1 to week 3 lead-times for Katrina, in comparison to Isabel. Some ensemble members forecasted hurricanes and storm surges as early as 3–4 weeks lead-time. However, due to the offsets developed in the timing and magnitude of the peak at these lead-times, and based on a sample size of only two events, it is hard to establish the significance of these longer lead-time results. While a follow up study involving flood reforecasts over the entire SubX reforecast period (1999–2015) is needed to support more robust statistics of the forecast skill, our case studies demonstrate the feasibility of probabilistic flood forecasting at subseasonal timescales using the SubX models.

Characterizing the Non-linear Interactions Between Tide, Storm Surge, and River Flow in the Delaware Bay Estuary, United States

Low-lying coastal areas in the mid-Atlantic region are prone to compound flooding resulting from the co-occurrence of river floods and coastal storm surges. To better understand the contribution of non-linear tide-surge-river interactions to compound flooding, the unstructured-grid Finite Volume Community Ocean Model was applied to simulate coastal storm surge and flooding in the Delaware Bay Estuary in the United States. The model was validated with tide gauge data in the estuary for selected hurricane events. Non-linear interactions between tide-surge-river were investigated using a non-stationary tidal analysis method, which decomposes the interactions’ components at the frequency domain. Model results indicated that tide-river interactions damped semidiurnal tides, while the tide-surge interactions mainly influenced diurnal tides. Tide-river interactions suppressed the water level upstream while tide-surge interaction increased the water level downstream, which resulted in a transition zone of damping and enhancing effects where the tide-surge-river interaction was prominent. Evident compound flooding was observed as a result of non-linear tide-surge-river interactions. Furthermore, sensitivity analysis was carried out to evaluate the effect of river flooding on the non-linear interactions. The transition zone of damping and enhancing effects shifted downstream as the river flow rate increased.

Ensemble generation for hurricane hazard assessment along the United States’ Atlantic coast

Atlantic tropical cyclones (TCs) affect the United States every year, and depending on their intensity, can cause coastal storm surge and inland inundation, leading to substantial damages in the east coast. Accurate TC risk assessment, however, is not easily quantified given the limited spatial and temporal historical records. This paper describes the development of a model framework for TC forecasts based on large ensemble generation. We illustrate the capability of the ensemble technique to improve TC forecasts by generating probabilistic forecasts of track and intensity. We show that the using this approach can generate tracks that are statistically similar to those of the underlying historical records, even TCs with long return periods. We began with historical compilations of the NOAA National Climatic Data Center (NCDC) tropical cyclone database. TCs reaching a hurricane strength and making landfall in or passing close to the United States were identified. The geographical area influenced by these hurricanes was discretized and the parameters of Markov chains and multivariate distributions were derived for each discretized area. Synthetic tracks were generated using repetitive random draws from the spatiotemporal distribution of historical genesis and storm motion, conditioned by Markov chains for each 6-hour displacement. Kolmogorov–Smirnov (K–S) tests revealed that the ensemble members and ’best track’ data are drawn from the same underlying population at the 95% significance level, with no test statistics exceeding the critical value of 0.13. The proposed algorithm is validated in both macro and micro scales. The results revealed that the general pattern of hurricane activities conforms well to the historical observations with high spatial correlations, over 90% for the Saffir–Simpson hurricane categories of 1 through 4 and near 80% for the category 5. The track generator also produces a history of potential wind and translational speeds for both of these scales.

Forecasting oceanfront shoreline position to evaluate physical vulnerability for recreational and infrastructure resilience at Cape Hatteras National Seashore

The Cape Hatteras National Seashore (Seashore) is located along the Outer Banks of eastern North Carolina, and is renowned for its prominent historical landmarks and world-class recreation. Seashore managers maintain hundreds of assets that support visitor use. Additionally, and primary to the mission of the National Park Service (NPS), managers steward natural and cultural resources located on public and protected lands. The portfolio of assets managed by NPS within the Seashore carries a high level of risk due to its exposure to both coastal erosion and storm surge inundation. The impacts of Hurricane Dorian demonstrated the importance of examining the physical vulnerability of the entire portfolio managed by NPS within the Seashore. The purpose of this study was to 1) evaluate the functionality of the beta forecast tool available in the Digital Shoreline Analysis System (v 5.0); and 2) explore options for using the output to assess the potential physical vulnerability of NPS assets. The study determined that using the 10- and 20-year oceanfront shoreline position forecast provides decision makers with a first order screening tool that can be used to prioritize mitigation and adaptation strategies given the unpredictable nature of tropical and extra-tropical cyclones and uncertainty associated with sea level rise.

Climate Change Implications Found in Winter Extreme Sea Level Height Records around Korea

The impact of climatic variability in atmospheric conditions on coastal environments accompanies adjustments in both the frequency and intensity of coastal storm surge events. The top winter season daily maximum sea level height events at 20 tidal stations around South Korea were examined to assess such impact of winter extratropical cyclone variability. As the investigation focusses on the most extreme sea level events, the impact of climate change is found to be invisible. It is revealed that the measures of extreme sea level events—frequency and intensity—do not correlate with the local sea surface temperature anomalies. Meanwhile, the frequency of winter extreme events exhibits a clear association with the concurrent climatic indices. It was determined that the annual frequency of the all-time top 5% winter daily maximum sea level events significantly and positively correlates with the NINO3.4 and Pacific Decadal Oscillation (PDO) indices at the majority of the 20 tidal stations. Hence, this indicates an increase in extreme event frequency and intensity, despite localized temperature cooling. This contradicts the expectation of increases in local extreme sea level events due to thermal expansion and global climate change. During El Nino, it is suggested that northward shifts of winter storm tracks associated with El Nino occur, disturbing the sea level around Korea more often. The current dominance of interannual storm track shifts, due to climate variability, over the impact of slow rise on the winter extreme sea level events, implies that coastal extreme sea level events will change through changes in the mechanical drivers rather than thermal expansion. The major storm tracks are predicted to continue shifting northward. The winter extreme sea level events in the midlatitude coastal region might not go through a monotonic change. They are expected to occur more often and more intensively in the near future, but might not continue doing so when northward shifting storm tracks move away from the marginal seas around Korea, as is predicted by the end of the century.

Developing Vulnerability Index for the Coastal Storm Surge Hazards Considering Climate Change

Developing Vulnerability Index for the Coastal Storm Surge Hazards Considering Climate Change

Dynamic Sea Level Variation From GNSS: 2020 Shumagin Earthquake Tsunami Resonance and Hurricane Laura

AbstractRapid determination of sea level variations caused by tsunamis or major storm surges is important for coastal hazard mitigation. Coastal Global Navigation Satellite Systems (GNSS) stations at elevations less than ∼300 m can record time‐varying sea level changes by tracking signals that reflect from the sea surface, relative to direct signals from the satellites. We demonstrate that such GNSS stations can rapidly provide local sea level measurements for a near‐field tsunami, involving many hours of shelf resonance generated by the 2020 Shumagin earthquake as well as for the storm surge accompanying passage of the eye of Hurricane Laura over the Louisiana Coast. Coastal GNSS stations deployed to measure tectonic deformation and co‐seismic displacements can inexpensively augment the spatial sampling provided by tide gauges for measuring tsunami‐induced coastal resonance and storm surges. This information can guide response activities during the crucial initial hours of an event.

Comparative Assessment of Livelihood Vulnerability of Climate Induced Migrants: A Micro Level Study on Sagar Island, India

The effects of climate change are causing large scale human displacements over the past few decades. Climate refugees are putting the biggest challenges to the geophysical biological and social system all over the world. This paper attempts to assess and compare the vulnerability of the climate-induced migrants and regular settlers of selected mouzas of Sagar Island, south 24parganas, India. People are witnessing their lands vanishing under their feet in these constantly sinking and shrinking deltaic estuaries of Sundarban. Findings of LVI and LVI-IPCC analysis indicate that the climate-induced migrant communities are more exposed to climatic variability due to the poor adaptive capacity. Moreover, poor access to food, water, health facilities is making them extremely vulnerable with lower resilience as these mouzas are facing frequent flooding, severe coastal erosion, embankment breaching and higher storm surge on annual basis. The outcomes of this study could be beneficial ineffective on-site risk management and planning propositions.

城市生态保护红线划定与管理——以澳门特别行政区为例

我国澳门特别行政区是世界上人口密度最高的地区之一，人地关系紧张。随着城市和经济的发展，人类空间与生态空间失调，城市生态和人居环境问题不断加剧。在建设美丽湾区、美丽澳门和人们对美好人居环境需求的背景下，通过划定城市生态保护红线以控制和维持现有重要功能生态空间，保护和改善高敏感生态空间，维护区域生态安全显得尤为重要。基于对澳门陆域生态系统调查，结合城市和自然资源特征，从生态系统服务功能、生态系统敏感性、生物多样性分布以及现有生态保护区四个方面构建了城市生态保护红线划定方法框架，选取并评估水源涵养、雨洪调节、热岛调节、土壤保持、海岸带防护五类调节服务和生态系统服务中的休闲游憩的空间格局，水土流失敏感性和海岸带风暴潮敏感性两种生态敏感性的分布，并综合澳门具有保育价值生物的栖息地分布和现有保护区范围进行了城市生态保护红线的划定。研究结果显示，澳门城市生态保护红线区域总面积6.71km²，占研究区面积的19.79%，覆盖了44%的生态空间、12.4%的海岸线、所有的重要物种栖息地及三分之一的古树名木。依照此生态保护红线研究进一步提出针对各类红线地块的保护和管理措施。研究提出的城市生态保护红线划定思路，可以为其他城市的重要生态空间保护、修复与管理提供参考。;Macao Special Administrative Region is one of the most densely populated regions in the world, and the human-land relationship is tense. The fast development of the city and economy resulted in the imbalanced pattern of human space and ecological space, and serious problems of urban ecology and human settlement environment. In the context of building a beautiful Bay Area and a beautiful Macao, and people’s demand for a better living environment, it is particularly important to control and maintain the existing vitally functional ecological space, and to protect and improve the highly sensitive ecological space by delimiting the urban ecological conservation redlines, so as to maintain regional ecological security. Based on the survey of the terrestrial ecosystem in Macao and by combining the characteristics of the city and natural resources, this paper constructed a framework for the delineation of urban ecological conservation redlines from four aspects, i.e., ecosystem service functions, ecosystem sensitivity, biodiversity distribution and existing ecological protection zones. We selected and evaluated five types of regulation services (including water conservation, rain and flood regulation, heat island regulation, soil conservation, and coastal protection) and leisure and recreation in ecosystem services, and analyzed distribution of the sensitivity of water and soil erosion and the coastal storm surge. The results were further combined with the distribution of habitats of the species with high conservation value in Macao and the scope of the existing protected areas, and the urban ecological conservation redlines were finally delineated. The total area within the delineated Macao's urban ecological conservation redlines was 6.71 km², accounting for 19.79% of the study area, which covered 44% of the ecological space, 12.4% of the coastline, all the important species habitats and one third of the ancient famous trees. Corresponding protection and management measures were also provided according to different kinds of land parcels in this ecological conservation redlines. The proposed frame and method of urban ecological redlines delineation could also provide reference for conservation, restoration and management of important urban ecological spaces in other cities.

A GIS-based screening method to identify climate change-related threats on road networks: A case study from Sweden

Extreme weather-related events are likely to increase in both frequency and intensity if current emission rates continue. Particularly vulnerable to the potential effects of climate change is the transportation sector, which fully relies on the uninterrupted accessibility of the road network. With the Swedish Government adopting a National Adaptation Strategy in 2018, creating a coordinated cross-disciplinary strategy underpinned by international frameworks, new ambition levels regarding climate change adaptation efforts have been established. Identifying particularly vulnerable parts of the road network is an essential step for National Road Authorities (NRAs) in early planning stages to prioritize adaptation efforts around high-risk areas to safeguard the road network. By utilizing both publicly and commercially available climate-related data, as well as applying and assessing new terrain analysis techniques, a large-scale vulnerability assessment is carried out for Halland County in southwestern Sweden by assessing three climate-adjusted extreme weather events (a 100-year pluvial flood event, a 100-year fluvial flood event, and an extreme coastal storm surge event) projected to exacerbate in the region. The study demonstrates how a GIS-based screening method, specifically adapted for NRAs or similar stakeholders, may provide quick overviews of potentially at-risk areas along road networks through a simple vulnerability index assigned to individual road segments. Further studies are recommended to compare modeled results to recorded flood events if available and incorporate updated climate change trajectories from upcoming IPCC reports.

A COMPREHENSIVE EVALUATION OF FLOOD HAZARDS FOR SABINE TO GALVESTON, TX, USA REGION

The Sabine Pass to Galveston Bay, TX Pre-Construction, Engineering and Design: Hurricane Coastal Storm Surge and Wave Hazard Assessment (S2G) includes flood hazard assessment for over 100 km of levee/floodwall/gate coastal storm risk management systems. The focus of the flood hazard assessment was to compute coupled water level and wave response near the structures, runup, and overtopping rate, combined hydrostatic and hydrodynamic pressure distributions on walls, overtopping nappe characteristics and other pertinent responses stochastically. Joint statistical analysis of forcing parameters, including epistemic uncertainty, was conducted to compute hazards. Design was based on varied confidence levels and thus reflected uncertainty. The approach brought high-fidelity components together to produce accurate probabilistic coastal flood hazard assessment.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/U_dFfj2oJ2A

IMPROVED COASTAL FLOOD RISK ESTIMATES THROUGH INTEGRATED JPM AND COUPLED PHYSICS APPROACH

Large scale flood risk computation has enjoyed a metamorphosis since Hurricane Katrina. Improved characterization of risk is the result of improved computational capabilities due to super computer capacity combined with coupled regional hydrodynamic models, improved local hydrodynamic models, improved joint probability models, inclusion of the most important uncertainties, metamodels and increased computational capacity for stochastic simulation. Improvements in our understanding of, and the ability to model, the coupled hydrodynamics of surge and waves has been well documented as has been improvements in the joint probability method with optimal sampling (JPM-OS) for synthesizing synthetic tropical cyclones (TC) that correctly span the practical hazard probability space. However, maintaining the coupled physics and multivariate probability integrity through the entire flood risk computation while incorporating epistemic uncertainty has had relatively little attention. This paper addresses this latter topic within the context of the Sabine Pass to Galveston Bay, TX Pre-Construction, Engineering and Design, Hurricane Coastal Storm Surge and Wave Hazard Assessment.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/qYFTO6l7UME

The interacting effects of storm surge intensification and sea-level rise on coastal resiliency: a high-resolution turbulence resolving case study

Climate change and global warming will increase the risk of coastal floods and storm surges, which can highly jeopardize communities and infrastructures along shorelines. There are two main drivers for this increase: surge amplification, which is caused by the projected hurricane intensification, and global sea-level rise (SLR). Although both factors can simultaneously affect storm surges, current knowledge on their interacting effects on the resiliency of coastal infrastructure is limited. To address this knowledge gap, we investigate the impacts of multiple storm surge scenarios on vehicles and buildings by varying wave heights, periods, and sea levels under current mitigation strategies. These surges are highly turbulent due to their high speed and wave-wave/bathymetry interactions. Large-scale numerical simulations with low-resolution (∼1–5 km) and depth-integrated models that do not resolve turbulence cannot assess the thorough impacts of these storm surges on infrastructures accurately. Hence, we employ a high-resolution numerical approach that is capable of resolving turbulent eddies down to ∼3 cm and capturing fluid-structure interactions. The distribution of hydrodynamic loads is found to vary nonlinearly in all directions with surge amplification and can significantly exceed calculations from classical theories that neglect turbulence. Two approaches from previous experiments are employed in a novel way to evaluate the resiliency of vehicles and infrastructure during storm surges. Our results indicate that vehicle mobility on the considered road will be imperiled by moderate surges (4 m wave height), and the elevated building will fail by surge intensification (8 m waves). We found that some storm-surge wave heights that are relatively safe now (e.g., 2 m waves for vehicles and 6 m for the building) will become hazardous in the future with an SLR. Therefore, road and building safety regulations should account for the interacting effects of hurricane intensification and SLR when devising mitigation strategies.

Retrieval of coastal typhoon storm surge using multi-GNSS-IR

Retrieval of coastal typhoon storm surge using multi-GNSS-IR

The Network Coordination Office of NHERI (Natural Hazards Engineering Research Infrastructure)

NHERI, or the Natural Hazards Engineering Research Infrastructure, is supported by the United States National Science Foundation (NSF) as a distributed, multi-user national facility that provides the natural hazards research community with access to a powerful research infrastructure. NHERI is comprised of separate research infrastructure awards for a Network Coordination Office (NCO), Cyberinfrastructure, a Computational Modeling and Simulation Center, eight Experimental Facilities, and CONVERGE (an initiative to advance social sciences and interdisciplinary research). Awards made for NHERI contribute to NSF's role in the National Earthquake Hazards Reduction Program and the National Windstorm Impact Reduction Program of the United States. The mission of NHERI is to provide the earthquake, wind, coastal engineering, and social sciences communities with access to research infrastructure, education, and community outreach activities focused on improving the resilience and sustainability of the civil infrastructure against earthquakes, windstorms, and associated natural events such as tsunami and coastal storm surge. In this paper, the role and key NHERI activities are described for the NCO, which is led by Purdue University, along with partner institutions—the University of Texas at San Antonio, North Carolina State University, Texas Tech University, the U.S. Naval Research Laboratory, and the University of Hawaii at Manoa. The NHERI NCO serves as a focal point and leader of a multi-hazards research community, and maintains a community-based NHERI science plan. It manages scheduling of our partner NHERI Experimental Facilities and coordinates all components to ensure effective and fair governance, efficient testing and user support within a safe environment. Another important role of the NCO is to lead NHERI-wide educational and outreach activities. The NCO works to develop strategic national and international partnerships and to coordinate NHERI activities with other awardee components to form a cohesive and fully-integrated global natural hazards engineering research infrastructure that fosters collaboration in new ways.

Household level vulnerability in an Indian mangrove socio-ecological system

ABSTRACT The Sundarbans (West Bengal) is highly vulnerable to hydro-meteorological hazards such as coastal storm surges, flooding, cyclones and other climatic events. These events often lead to loss of productivity in ecosystem-based livelihoods, biodiversity, ecosystem goods and services. Communities directly dependent on socio-ecological systems for primary livelihood need to strengthen their resilience for early recovery and prepare for the impacts of future hazards. Current policies often assume that households are equally vulnerable to hazards. However, there is no robust empirical study available on the level and distribution of vulnerability amongst marginalised households. This study compared the levels of vulnerability amongst 500 households in five villages situated in the Mangrove ecosystem of the Indian Sundarban using the Livelihood Vulnerability Index (LVIs). The results uncover significant variations in levels and distribution of vulnerability between the villages. These findings could be used to tailor need-based bespoke adaptation and mitigation interventions to combat climate-induced variability or hazard events in the future. In order to optimise the benefits of policy or program for strengthening resilience of these households – this article recommends that policymakers consider micro-level differences in levels and distribution of vulnerability.

Fine-Scale Coastal Storm Surge Disaster Vulnerability and Risk Assessment Model: A Case Study of Laizhou Bay, China

In the assessment of storm surge vulnerability, existing studies have often selected several types of disaster-bearing bodies and assessed their exposure. In reality, however, storm surges impact all types of disaster-bearing bodies in coastal and estuarine areas. Therefore, all types of disaster-bearing bodies exposed to storm surges should be considered when assessing exposure. In addition, geographical factors will also have an impact on the exposure of the affected bodies, and thus need to be fully considered. Hence, we propose a fine-scale coastal storm surge disaster vulnerability and risk assessment model. First, fine-scale land-use data were obtained based on high-resolution remote sensing images. Combined with natural geographic factors, such as the digital elevation model (DEM), slope, and distance to water, the exposure of the disaster-bearing bodies in each geographic unit of the coastal zone was comprehensively determined. A total of five indicators, such as the percentage of females and ratio of fishery products to the gross domestic product (GDP), were then selected to assess sensitivity. In addition, six indicators, including GDP and general public budget expenditure, were selected to assess adaptability. Utilizing the indicators constructed from exposure, sensitivity, and adaptability, a vulnerability assessment was performed in the coastal area of Laizhou Bay, China, which is at high risk from storm surges. Furthermore, the storm surge risk assessment was achieved in combination with storm water statistics. The results revealed that the Kenli District, Changyi City, and the Hanting District have a higher risk of storm surge and require more attention during storm surges. The storm surge vulnerability and risk assessment model proposed in this experiment fully considers the impact of the natural environment on the exposure indicators of the coastal zone’s disaster-bearing bodies, and combines sensitivity, adaptability indicators, and storm water record data to conduct vulnerability and risk assessment. At the same time, the model proposed in this study can also realize multi-scale assessment of storm surge vulnerability and risk based on different scales of socioeconomic statistical data, which has the advantages of flexibility and ease of operation.

Disturbance legacies increase and synchronize nutrient concentrations and bacterial productivity in coastal ecosystems.

Long‐term ecological research can resolve effects of disturbance on ecosystem dynamics by capturing the scale of disturbance and interactions with environmental changes. To quantify how disturbances interact with long‐term directional changes (sea‐level rise, freshwater restoration), we studied 17 yr of monthly dissolved organic carbon (DOC), total nitrogen (TN), and phosphorus (TP) concentrations and bacterioplankton productivity across freshwater‐to‐marine estuary gradients exposed to multiple disturbance events (e.g., droughts, fire, hurricanes, and low‐temperature anomalies) and long‐term increases in water levels. By studying two neighboring drainages that differ in hydrologic connectivity, we additionally tested how disturbance legacies are shaped by hydrologic connectivity. We predicted that disturbance events would interact with long‐term increases in water levels in freshwater and marine ecosystems to increase spatiotemporal similarity (i.e., synchrony) of organic matter, nutrients, and microbial activities. Wetlands along the larger, deeper, and tidally influenced Shark River Slough (SRS) drainage had higher and more variable DOC, TN, and TP concentrations than wetlands along the smaller, shallower, tidally restricted Taylor River Slough/Panhandle (TS/Ph) drainage. Along SRS, DOC concentrations declined with proximity to coast, and increased in magnitude and variability following drought and flooding in 2015 and a hurricane in 2017. Along TS/Ph, DOC concentrations varied by site (higher in marine than freshwater wetlands) but not year. In both drainages, increases in TN from upstream freshwater marshes occurred following fire in 2008 and droughts in 2010 and 2015, whereas downstream increases in TP occurred with coastal storm surge from hurricanes in 2005 and 2017. Decreases in DOC:TN and DOC:TP were explained by increased TN and TP. Increases in bacterioplankton productivity occurred throughout both drainages following low‐temperature events (2010 and 2011) and a hurricane (2017). Long‐term TN and TP concentrations and bacterioplankton productivity were correlated (r > 0.5) across a range of sampling distances (1–50 km), indicating spatiotemporal synchrony. DOC concentrations were not synchronized across space or time. Our study advances disturbance ecology theory by illustrating how disturbance events interact with long‐term environmental changes and hydrologic connectivity to determine the magnitude and extent of disturbance legacies. Understanding disturbance legacies will enhance prediction and enable more effective management of rapidly changing ecosystems.