Inundation Events Research Articles

Limited plankton community shifts over winter inundation events in Austral temporary wetlands

ABSTRACT Plankton are key components of wetland ecosystems, comprising different food web levels. In the present study, we assessed temporal plankton diversity patterns in three temporary wetland systems over winter inundation periods. We examined taxon relationships with environmental variability associated with wetland inundation phase changes, over six consecutive sampling events (i.e. T1–T6; or until the ponds dried). Fifty-nine phytoplankton species belonging to 36 genera were identified across the three wetlands, with 21, 22 and 19 taxa being identified for Wetlands 1, 2 and 3, respectively. Twenty-five zooplankton taxa were also identified across the three wetlands. Significant differences in environmental variables were found across sampling events. Ammonium, conductivity, dissolved oxygen, water temperature, turbidity, nitrates (NO3–N) and zooplankton abundances were identified as important variables structuring phytoplankton communities, whereas, NO3–N, phosphates and chlorophyll-a concentration were identified as important environmental variables for zooplankton. No significant differences were, however, observed in plankton community structure over time or among wetlands. Accordingly, hydroperiod phases did not have any significant influence on the plankton taxa richness in this study, in contrast to other seasons in the region and other parts of the world. The present study highlights that where temporary wetlands are characterised by both summer and winter inundation events, community succession dynamics may be seasonally distinct and require sampling in both periods to fully understand propagule and emergent community dynamics.

Inundation prediction in tropical wetlands from JULES-CaMa-Flood global land surface simulations

Abstract. Wetlands play a key role in hydrological and biogeochemical cycles and provide multiple ecosystem services to society. However, reliable data on the extent of global inundated areas and the magnitude of their contribution to local hydrological dynamics remain surprisingly uncertain. Global hydrological models and land surface models (LSMs) include only the most major inundation sources and mechanisms; therefore, quantifying the uncertainties in available data sources remains a challenge. We address these problems by taking a leading global data product on inundation extents (Global Inundation Extent from Multi-Satellites, GIEMS) and matching against predictions from a global hydrodynamic model (Catchment-based Macro-scale Floodplain – CaMa-Flood) driven by runoff data generated by a land surface model (Joint UK Land and Environment Simulator, JULES). The ability of the model to reproduce patterns and dynamics shown by the observational product is assessed in a number of case studies across the tropics, which show that it performs well in large wetland regions, with a good match between corresponding seasonal cycles. At a finer spatial scale, we found that water inputs (e.g. groundwater inflow to wetland) became underestimated in comparison to water outputs (e.g. infiltration and evaporation from wetland) in some wetlands (e.g. Sudd, Tonlé Sap), and the opposite occurred in others (e.g. Okavango) in our model predictions. We also found evidence for an underestimation of low levels of inundation in our satellite-based inundation data (approx. 10 % of total inundation may not be recorded). Additionally, some wetlands display a clear spatial displacement between observed and simulated inundation as a result of overestimation or underestimation of overbank flooding upstream. This study provides timely information on inherent biases in inundation prediction and observation that can contribute to our current ability to make critical predictions of inundation events at both regional and global levels.

Measurement Approach to Develop Flood-Based Damage Fragilities for Residential Buildings Following Repeat Inundation Events

Measurement Approach to Develop Flood-Based Damage Fragilities for Residential Buildings Following Repeat Inundation Events

Satellite-Based Flood Inundation and Damage Assessment

Because recurring floods in the Philippines have become more damaging throughout time, risk assessments, quantifying, and visualizing flood damages as accurately as possible become imperative. To deal with an up-todate database and a practical assessment tool, a satellite imagery-based method was used which aimed to map flood inundation and estimate damages brought by the flood during Typhoon Ulysses. This paper presents a framework for an integrated flood risk management in a river basin context with the following components as follows: 1) collection of the comprehensive database containing information relevant for flood analysis; 2) use of a satellite-imagery based method for flood inundation map using Google Earth engine; 3) validation of map accuracy through quick post-flood participatory approach. Analysis of the recent flood inundation event in November 2020 in Cagayan Valley, Philippines showed the inundation of an extensive area of 620.88 km2 affecting the Cagayan province at 55.91% and Isabela province at 44% share of inundation. The flood severely affected approximately 614.05 km2 of the total croplands. Using a participatory validation approach, the overall accuracy of datasets used is 97.78% while flood extent is 95%. Through this study, the framework, approach, and methodology can be replicated in other locations in the Philippines and in other countries which recurrently experience flooding.

Micropollutant content of Sargassum drifted ashore: arsenic and chlordecone threat assessment and management recommendations for the Caribbean.

Massive Sargassum beachings occurred since 2011 on Caribbean shores. Sargassum inundation events currently involve two species, namely S. fluitans and S. natans circulating and blooming along the North Atlantic subtropical gyre and in the entire Caribbean region up to the Gulf of Mexico. Like other brown seaweeds, Sargassum have been shown to bioaccumulate a large number of heavy metals, alongside with some organic compounds including the contamination by historical chlordecone pollution in French West Indies (FWI), an insecticide used against the banana's weevil Cosmopolites sordidus. The present study reports, during two successive years, the concentration levels of heavy metals including arsenic in Martinique and Guadeloupe (FWI). We found that Sargassum can also accumulate a high concentration of chlordecone. Sargassum contamination by chlordecone is observed in areas close to contaminated river mouth but can be partly due to chlordecone desorption when secondary drifted on chlordecone-free shore. Our results further demonstrate that algae bleaching raises a number of questions about inorganic and organic pollutant (i) bioaccumulation, at sea for arsenic and close to river plumes for chlordecone, (ii) transport, and (iii) dissemination, depending the shoreline and the speciation for arsenic and/or metabolization for both.

A paradise went under– the unique hydrology of the atlas basin recorded in the pyramid texts

The Pyramid Texts portray a detailed, specific, and vivid scene of akhification (spiritual rebirth), including the positions, shapes, depths, colors, temperatures, inundation events, vegetation, and salinity of the bodies of water as well as the human activities of religion, irrigation, farming, and ferry around the Akhet. This paper reveals that this scene was an actual environment in the Atlas Basin right before the end of the green Sahara. All the above details exactly describe the characteristics of the two terminal megalakes of the basin, based on the water cycle of the green Sahara. The Akhet located at the outlet of the canal connecting these two lakes was a continuation of Atlantis. Most importantly, the Pyramid Texts tell us that, with advanced hydraulic and agricultural technologies, Atlanteans unknowingly triggered the water cycle collapse in the Atlas Basin and inflicted a breach to the green Sahara.

Impact of the Great Flood of 2016 on the Asphaltic Concrete Road Infrastructure in Louisiana

Extreme weather events, including inundation, are the major causes of weather-related disruption to the transportation sector. Considerable research has been conducted in recent years to evaluate the impacts of inundation on pavement functional and structural conditions. Yet, limited studies quantified how inundation may affect the long-term pavement performance and pavement life-cycle costs. As such, the main objective of this study was to quantify the impact of the 2016 inundation event in Louisiana, U.S., on the long-term pavement performance (in relation to reduction in the pavement service life [PSL]) and on pavement life-cycle costs. To achieve this objective, a total of 10 inundated pavement sections were evaluated. Pavement conditions, fatigue, and rutting indices for these sections were analyzed over a monitoring period of up to 15 years (11 years before and 4 years after inundation). Results indicated that the 2016 inundation event reduced the PSL of the inundated sections to an extent that depended on their pre-flooding pavement condition, traffic level, and asphalt concrete thickness. This reduction was attributed to the accelerated fatigue, rutting damage, or both, that resulted from prolonged water submergence and heavy traffic loading during debris hauling that took place after the inundation event. A logistic regression model with adequate accuracy was developed to predict whether an inundated pavement would experience reduction in its PSL based on the project conditions. The study findings were incorporated into a simple tool to assist transportation agencies make effective decisions for the maintenance and rehabilitation of inundated pavements.

A sensitivity study of rising compound coastal inundation over large flood plains in a changing climate

Coastal flood hazards and damage to coastal communities are increasing steeply and nonlinearly due to the compound impact of intensifying tropical cyclones (TCs) and accelerating sea-level rise (SLR). We expand the probabilistic coastal flood hazard analysis framework to facilitate coastal adaptation by simulating the compound impact of predicted intensifying TCs and rising sea levels in the twenty-first century. We compared the characteristics of landfalling TCs in Florida (FL) and southwest Florida (SWFL) for the late twentieth and twenty-first centuries predicted by several climate models and downscaling models. TCs predicted by four climate models, one without downscaling and three with downscaling, were used by a coupled surge-wave model to predict the future flood hazard due to compound effects of TCs and SLR over a large SWFL coastal flood plain. By 2100, the coastal inundation metrics of the 1% annual chance coastal flood could become almost 3–7 folds of their current values, depending on the climate and downscaling models, Representative Concentration Pathway scenarios, Atlantic Multi-decadal Oscillation phases, TCs, SLR, precipitation, and how TCs and SLR are incorporated. By 2100, the current 1% (100-year) inundation event could become a 3-year event, and the 0.2% (500-year) inundation event could become a 5-year event.

Why do sea turtle nests fail? Modeling clutch loss across the southeastern United States

AbstractUnderstanding the relative influence of environmental conditions and disturbance types on species' nest success is imperative to our estimation of current and future population trajectories of vulnerable species, especially ectotherms. The reproductive output of oviparous species is highly dependent on the location of a nest in terms of the environment experienced by incubating embryos and the risk of disturbance events. Climate change may present a particular danger to oviparous species because eggs cannot behaviorally regulate and avoid extreme temperatures. Hierarchical Bayesian models offer a powerful tool for utilizing available long‐term datasets to predict current and future species–environment relations in a manipulatable framework. We modeled the probability of depredation and inundation events occurring during incubation and how these disturbances, along with local climate, predict total clutch failure for loggerhead sea turtles (Caretta caretta) using a dataset of over 9000 nest inventories from five nesting areas that span the latitudinal extent of primary nesting locations in the United States. We found that nesting distance from the high waterline was important in determining the probability of inundation and depredation disturbance events, as well as clutch failure. Nests that experienced at least one inundation event were more likely to have no emergence than nests that experienced at least one depredation event, which may be the result of concerted efforts to control highly destructive nest predators in our study sites or the magnitude of inundation disturbances. Extreme high‐temperature events increased the probability of clutch failure, but the probability of clutch failure decreased with increasing average temperatures up to a critical threshold. The results of these models have clear implications for conservation management decisions on where to deploy predator deterrents and relocate nests, as well as the potential for predicting future changes in nest productivity across the broad nesting range of loggerhead sea turtles.

Boulder Dislodgement During Coastal Storms and Tsunamis: Insights From a New Ensemble Model

AbstractBoulders are excellent candidate deposits to study coastal inundation events by storms and tsunamis due to their significant preservation potential. However, it is difficult to infer how and what forcing dislodged the boulder. We present a new model that enables ensemble and Monte‐Carlo‐type simulations to study the sensitivity of boulder, the fluid flow, and environmental parameters. Our examples show that boulder transport is complex and nonlinear, and to acknowledge the uncertainties of the boulder's preexisting transport conditions, a range of velocities and environmental parameters should be used to quantify the flow that caused boulder dislodgement.

THE EFFECT OF GROUNDWATER DEPTH ON FLOODING IN THE REGION OF PASAR MINGGU DISTRICT,DKI JAKARTA PROVINCE

The flood disaster that hit the capital city cannot be separated from the lives of the people living around it. Every time it rains, the city of Jakarta has never been separated from notifications about inundation or flooding events. The purpose of this study is to review the factors that cause inundation or flooding in the city of Jakarta and its surroundings, especially the Pasar Minggu sub-district, on the influence of the depth of the groundwater table. The author collects library materials in the form of lithological conditions of the research area, annual rainfall data in the research area and performs direct measurements of the depth of the groundwater table in the research area. The results of this study are to provide a review regarding the research area is a flooded area so that after all this inundation event is difficult to remove from the area of Jakarta and its surroundings based on the calculation of groundwater depth.Keywords: inundation, lithology, groundwater level

Spatial and Seasonal Patterns of Flood Inundation in Lokoja, Kogi State, Nigeria

The study examines spatial patterns of flood inundation in Lokoja, Kogi state, Nigeria. Maximum Likelihood Classifier algorithm of the supervised land use/cover classification technique was utilized. The results obtained from the analysis were used to estimate the magnitude and visualize the seasonal and spatial pattern of flood inundation event. Eight Landsat Images comprising of two sets for each year (dry and wet seasons) were acquired from the portal of United States Geological Survey (2018). The Landsat images were classified into land cover classes such as Built Up, Vegetation and Water Body. After completing the land cover classification, the area of each class was determined and converted to square kilometers and percentages for both wet and dry seasons. Based on the classification, the brown colour depicts the built-up areas, blue for water body, and green for vegetation. Finally, accuracy assessment was carried out using historical Google Earth images, informed knowledge of the area, and GPS coordinates. ArcMap 10.5 was used to produce land use/cover maps for the study period. The result overall, revealed the effect of flood inundation to be more intense on vegetation. 1.62%, 4.60%, 23.05% and 6.43% of vegetated land was lost in 1999, 2009, 2012 and 2018, respectively. Therefore, efforts to improve resilience against variable weather, flood inundation and seasonal uncertainties should be encouraged.

Reported Occurrence of Multiscale Flooding in an Alpine Conurbation over the Long Run (1850–2019)

This paper deals with the identification of extreme multiscale flooding events in the Alpine conurbation of Grenoble, France. During such events, typically over one to several days, the organization in space and time of the generating hydrometeorological situation triggers the concurrent reaction of varied sets of torrents and main rivers and creates diverse socioeconomic damages and disruptions. Given the limits of instrumental data over the long run, in particular at the torrent scale, we explore the potential of a database of reported extreme flood events to study multiscale flooding over a Metropolitan domain. The definition of Metropolitan events is mainly based on the database built by the RTM (Restauration des Terrains de Montagne, a technical service of the French Forest Administration). Relying on expert reports, the RTM database covers the long lifetime of this French national service for the management of mountainous areas (1850–2019). It provides quantitative information about the time and place of inundation events as well as qualitative information about the generating phenomena and the consequent damages. The selection process to define Metropolitan events simply chronologically explores the RTM database and complements it with historical research data. It looks for concurrence between site events at the same date under a chosen set of criteria. All scales together, we selected 104 Metropolitan events between 1850 and 2019. Exploring the list of dates, we examine the homogeneity of the Metropolitan events over 1850–2019 and their space–time characteristics. We evidence the existence of multiscale flooding at the Metropolitan scale, and we discuss some implications for flood risk management.

Spatial and Seasonal Patterns of Flood Inundation in Lokoja, Kogi State, Nigeria

The study examines spatial patterns of flood inundation in Lokoja, Kogi state, Nigeria. Maximum Likelihood Classifier algorithm of the supervised land use/cover classification technique was utilized. The results obtained from the analysis were used to estimate the magnitude and visualize the seasonal and spatial pattern of flood inundation event. Eight Landsat Images comprising of two sets for each year (dry and wet seasons) were acquired from the portal of United States Geological Survey (2018). The Landsat images were classified into land cover classes such as Built Up, Vegetation and Water Body. After completing the land cover classification, the area of each class was determined and converted to square kilometers and percentages for both wet and dry seasons. Based on the classification, the brown colour depicts the built-up areas, blue for water body, and green for vegetation. Finally, accuracy assessment was carried out using historical Google Earth images, informed knowledge of the area, and GPS coordinates. ArcMap 10.5 was used to produce land use/cover maps for the study period. The result overall, revealed the effect of flood inundation to be more intense on vegetation. 1.62%, 4.60%, 23.05% and 6.43% of vegetated land was lost in 1999, 2009, 2012 and 2018, respectively. Therefore, efforts to improve resilience against variable weather, flood inundation and seasonal uncertainties should be encouraged.

Tidally-Driven Gas Exchange in Beaches: Implications for Sea Turtle Nest Success

Goforth, K.M. and Carthy, R.R., 2022. Tidally-driven gas exchanges in beaches: Implications for sea turtle nest success. Journal of Coastal Research, 38(3), 523–537. Coconut Creek (Florida), ISSN 0749-0208. The success of individual sea turtle nests is influenced by nest location on the beach and the resulting incubation environment. Several abiotic factors affect nest incubation, and thus nest success, but tides and gas exchange are two of the most important. The effects of tides on nest success have been well documented in regard to overwash and inundation events. However, the possible effect of tidally-driven gas exchange has received little attention. The incursion and retreat of the saltwater wedge may cause substantial movement of gases through the beach during the tidal cycle. This study quantifies the differences in tidally-driven gas exchange among beach types and shoreline elevation levels. Carbon dioxide (CO2) efflux was used as a means of measuring gas movement through the beach to examine tidal effects across different beach zones and among different beach types. CO2 efflux was measured throughout the tidal cycle at three distinct beaches (accreting, eroding, and nourished) at Cape San Blas, Florida. There was a general pattern of CO2 efflux rising and falling throughout the tidal cycle on each beach and a difference in the CO2 efflux observed among beaches and beach zones. Efflux patterns at the nourished and eroding beaches were similar, but the nourished beach exhibited a decreased and dampened CO2 efflux pattern throughout the course of the tidal cycle. Analyses of the hatchling turtle emergence success data from 2011 to 2014 for the three beaches found that emergence success differed among the three beaches. The highest emergence success was on the nourished beach, which exhibited a relatively consistent efflux pattern. These results suggest that tidally-driven gas exchange may have implications on nest incubation and survival and are a consideration in beach restoration management and best practices for coastline conservation.

Monitoring Sargassum Inundation on Beaches and Nearshore Waters Using PlanetScope/Dove Observations

<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Sargassum</i> beaching events have been reported in recent years around the Caribbean Sea and FL, USA, causing numerous environmental and economic problems. Satellite remote sensing has been widely used to monitor <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Sargassum</i> blooms in open waters, yet due to either coarse spatial resolution or low-revisit frequency, it is difficult to provide timely information on <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Sargassum</i> inundation from traditional satellite instruments. In this study, we demonstrate the capacity of 3-m resolution daily Dove imagery in monitoring <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Sargassum</i> beaching events on Miami beach (FL, USA) and Cancun beach (Mexico). A U-net deep learning (DL) computer model is developed to extract <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Sargassum</i> features from Dove imagery over beaches and nearshore waters. Application of the model to Dove image sequences between May and August 2019 shows two major inundation events on both Miami beach and Cancun beach, consistent with local reports. With the availability of 3-m resolution PlanetScope/Dove and PlanetScope/SuperDove data around the globe, the findings suggest that it is possible to monitor dynamic inundation events of not only <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Sargassum</i> but also other macroalgae in many other regions.

Late Holocene palaeogeographic evolution of the Lihoura coastal plain, Pteleos Gulf, Central Greece

The present study aims to determine the Late Holocene palaeogeographic evolution of the coastal Lihoura plain located at the western part of Pteleos Gulf, in central-eastern Greece. The study area is a low-lying marsh, located at the mouth of an ephemeral stream. In order to determine the evolution of the plain, three cores (max. depth of 6 m) were drilled. Grain size analysis coupled with macro- and micro-palaeontological analyses were performed on sediment samples collected from the cores and six biosedimentary facies were identified corresponding to different depositional palaeoenvironments. The chronostratigraphy of the cores was established by 14C radiocarbon datings on three samples. Furthermore, detailed (at a scale 1:5000) geomorphological mapping was carried out, providing us with valuable information on the palaeogeographic evolution of the area. The results suggest that during the Mid-Holocene, the sea inundated the Lihoura Bay and created a transitional marine-brackish environment. The existence of an elongated (SW-NE) limestone peninsula along with the development of a sand bar shortly after 5027–5462 cal yrs BP, led to the formation of a protected lagoonal environment at the western part of the marshy plain, which at times was influenced by multiple terrestrial inputs induced by fluvial sediment supply. At the northern part of the marshy plain, a very recent high energy marine inundation event has been recorded in the sedimentary stratigraphy. Average rates of relative sea-level rise of 0.78 ± 0.24 mm/yr, 0.94 ± 0.24 mm/yr and 1.45 ± 0.77 mm/yr were estimated for the last 5244.5 ± 217.5 cal yrs BP, 5543 ± 196 cal yrs BP and 1901 ± 200 cal yrs BP respectively, which is in good agreement with previously published sea-level data for the broader area.

Dryland Watershed Restoration With Rock Detention Structures: A Nature-based Solution to Mitigate Drought, Erosion, Flooding, and Atmospheric Carbon

Historic land degradation is an ongoing threat to the Sky Islands of southern Arizona, US, and northern Sonora, Mexico, an area designated as a globally significant biodiversity hotspot. Land degradation has reduced ecosystem services provisioning, released carbon from disturbed soils into the atmosphere, and significantly diminished resilience to climate change. Private land managers in the region have developed methods to reverse degradation and restore biodiversity and ecosystem function. Land managers have used rock detention structures (RDS), technology adapted from traditional Indigenous practices in the region, as a tool for reversing desertification and watershed degradation. The structures were installed primarily for erosion control and water management, but they have had positive impacts on multiple biophysical systems. In this study, we analyze watershed-scale installation of RDS as a nature-based solution for climate change mitigation and adaptation. Case studies include four properties that offer examples of structures that have been in place over a period ranging from 1 to 40 years. We reviewed journal articles and other studies conducted at the four sites, supplemented with interviews, to catalogue the nature-based solutions provided by RDS. This study documents positive impacts on overall stream flow, reduction in peak runoff during inundation events, and increased sedimentation, which increase resilience to drought, erosion, and flooding. Data suggest potential impacts for climate change mitigation, though further research is needed. In addition, results suggest that watershed restoration with RDS offers a host of co-benefits, including an increase in biodiversity and wildlife abundance, an increase in vegetative cover, and increased surface water provisioning over time to support the land-based livelihoods of downstream neighbors. In the discussion, we consider barriers to replication and scalability using the strategy of the UN Decade on Ecosystem Restoration as a guiding framework, discussing issues of awareness, legislation and policy, technical capacity, finance, and gaps in knowledge.

Storm surge induced sediment accumulation on marsh islands in the southeastern North Sea: Implications for coastal protection

Coastal marshlands in tide-dominated shallow marine systems are prone to erosion and vulnerable to long term sea level rise. The natural adaptability of such areas mainly depends on sufficient sediment supply delivered during inundation events and protection against erosion processes. Artificial structures such as dykes, revetments and tidal gates ensure protection against erosion but influence the natural adaptability of the marshland. Establishing a reasonable balance between natural adaptation processes and coastal protection measures forms a challenging task. With the use of an autonomously operating turbidity sensor network and sediment traps installed at and around a marsh island in the North Frisian Wadden Sea (Hallig Langeness, Germany), we measured suspended particulate matter (SPM) concentrations and vertical accretion adjacent to artificial revetments and breakwater constructions. Measurements included seven storm surges in the winter season 2019/20 with peak water levels of 2.94–3.65 m above sea level. We found clear relations between SPM on the tidal flats and SPM on the marshland. While SPM concentrations in the tidal flats (SPMi) during storm surges range from 0.5 ± 0.014 to 1.14 ± 0.014 g/l, those in the marshland behind breakwaters (SPMrs) only reach on average 28%–47% of SPMi depending on the specific location. SPMrs/SPMi and peak water levels shows positive correlation, while SPMrs and the duration needed to fully inundate the marshland exhibits a negative correlation. Vertical accretion of the marshland is 7.4 ± 4.6 mm for the winter season 2019/20 and therefore about 2.6 times higher than the average for four years (2016–2020) at 2.8 ± 2 mm/a. The average vertical accretion per inundation increases from 0.2 mm at moderate inundations to 0.84 mm at storm surges. The hampering effect of breakwaters on sediment accumulation seems to diminish at storm surges compared to moderate inundations.

A Just Transition to Climate-resilient Coastal Communities in Aotearoa New Zealand

Even if global emissions of greenhouse gases were to fall to zero immediately, still we would expect significant sea level rise over the next half century, along with increased frequency and intensity of inundation events and coastal erosion. While this fact has been widely appreciated by public servants and policymakers, the ethical implications and distributive consequences of our climate adaptation policy decisions have not. Decisions to allow new development in areas likely to become uninhabitable could transfer investment risks from property owners to the public, for example, while decisions to relocate existing at-risk communities could disempower already relatively disadvantaged groups. A just transition to climate-resilient coastal communities will require reduced policy uncertainty and enhanced democratic decision making.