Will hurricane sedimentation aid southeastern US saltmarsh resiliency in the face of climate change and sea-level rise?

2021 ◽  
Author(s):  
Alice Staro ◽  
Duncan FitzGerald ◽  
Zoe Hughes ◽  
Christopher Hein ◽  
Ioannis Georgiou ◽  
...  
Keyword(s):  
Climate Change ◽  
South Carolina ◽  
Sea Level Rise ◽  
Sea Level ◽  
Storm Surge ◽  
Salt Marshes ◽  
Marsh Surface ◽  
Organic Content ◽  
Southeastern Us ◽  
Hurricane Irma

<p>Coastal saltmarshes are an important and highly diverse ecosystem, shielding the mainland from erosion and flooding. Along the US East Coast these valuable wetlands are endangered due to climate change, sea-level rise, and reduced fluvial sediment fluxes. Although hurricanes are commonly an erosional agent, they may be responsible for delivering significant volumes of sediment to the marsh surface, which could aid resiliency by increasing vertical accretion. This study analyzes marsh sediment cores collected during December 2017 within the Georgia Bight, targeting deposits associated with Hurricane Irma, which caused significant wave energy and storm surge along the coast from Florida to South Carolina in September 2017.</p><p>We have focused our initial research on samples from Sapelo Island (Georgia), where Hurricane Irma produced maximum wind velocities of 17.5 m/s and a 1.3 m storm surge, inundating the marsh for 14.8 hrs. We find that Irma-related layers are between 2 and 7 cm thick and well-oxidized. These deposits typically consist of laminated mud with low organic content (LOI: 10-25%) and low bulk density (0.3-0.8 g/cm<sup>3</sup>). On average, Irma event sediment thickness is 4 times the historical average annual accretion, which in Georgia salt marshes is 1.55 mm.</p><p>A direct comparison of Irma-affiliated marsh accretion and historical rates is complicated due to differences in consolidation, rooting and vegetation, and the sedimentation history of the marsh. Nonetheless, the storm layer represents a significant addition of sediment to the marsh surface. Thus, future increases in event sedimentation, associated with increased frequency or severity of storms, could help compensate for sea-level rise and lessen the likelihood or extent of marsh loss due to submergence.</p>

Marsh Processes and Their Response to Climate Change and Sea-Level Rise

2019 ◽  
Vol 47 (1) ◽  
pp. 481-517 ◽  
Author(s):  
Duncan M. FitzGerald ◽  
Zoe Hughes
Keyword(s):  
Climate Change ◽  
Carbon Dioxide ◽  
Sea Level Rise ◽  
Suspended Sediment ◽  
Sea Level ◽  
Salt Marshes ◽  
Biomass Productivity ◽  
Sediment Supply ◽  
Marsh Vegetation ◽  
Suspended Sediment Concentrations

In addition to their being vital components of mid- to high-latitude coastal ecosystems, salt marshes contain 0.1% of global sequestered terrestrial carbon. Their sustainability is now threatened by accelerating sea-level rise (SLR) that has reached a rate that is many times greater than the rate at which they formed and evolved. Modeling studies have been instrumental in predicting how marsh systems will respond to greater frequencies and durations of tidal inundation and in quantifying thresholds when marshes will succumb and begin to disintegrate due to accelerating SLR. Over the short term, some researchers believe that biogeomorphic feedbacks will improve marsh survival through greater biomass productivity enhanced by warmer temperatures and higher carbon dioxide concentrations. Increased sedimentation rates are less likely due to lower-than-expected suspended sediment concentrations. The majority of marsh loss today is through wave-induced edge erosion that beneficially adds sediment to the system. Edge erosion is partly offset by upland marsh migration during SLR. ▪ Despite positive biogeomorphic feedbacks, many salt marshes will succumb to accelerating sea-level rise due to insufficient mineral sediment. ▪ The latest multivariate marsh modeling is producing predictions of marsh evolution under various sea-level rise scenarios. ▪ The least well-known variables in projecting changes to salt marshes are suspended sediment concentrations and net sediment influx to the marsh. ▪ We are in the infancy of understanding the importance and processes of marsh edge erosion and the overall dynamicism of marshes. ▪ This review defines the latest breakthroughs in understanding the response of salt marshes to accelerating sea-level rise and decreasing sediment supply. ▪ Climate change is accelerating sea-level rise, warming temperatures, and increasing carbon dioxide, all of which are impacting marsh vegetation and vertical accretion.

Analysis of Flood Vulnerability and Transit Availability with a Changing Climate in Harris County, Texas

2019 ◽  
Vol 2673 (6) ◽  
pp. 258-266 ◽  
Author(s):  
Joshua A. Pulcinella ◽  
Arne M. E. Winguth ◽  
Diane Jones Allen ◽  
Niveditha Dasa Gangadhar
Keyword(s):  
Climate Change ◽  
Sea Level Rise ◽  
Sea Level ◽  
Storm Surge ◽  
Extreme Weather ◽  
Extreme Weather Events ◽  
Harris County ◽  
Weather Events ◽  
Block Groups ◽  
The Impact

Hurricanes and other extreme precipitation events can have devastating effects on population and infrastructure that can create problems for emergency responses and evacuation. Projected climate change and associated global warming may lead to an increase in extreme weather events that results in greater inundation from storm surges or massive precipitation. For example, record flooding during Hurricane Katrina or, more recently, during Hurricane Harvey in 2017, led to many people being cut off from aid and unable to evacuate. This study focuses on the impact of severe weather under climate change for areas of Harris County, TX that are susceptible to flooding either by storm surge or extreme rainfall and evaluates the transit demand and availability in those areas. Future risk of flooding in Harris County was assessed by GIS mapping of the 100-year and 500-year FEMA floodplains and most extreme category 5 storm tide and global sea level rise. The flood maps have been overlaid with population demographics and transit accessibility to determine vulnerable populations in need of transit during a disaster. It was calculated that 70% of densely populated census block groups are located within the floodplains, including a disproportional amount of low-income block groups. The results also show a lack of transit availability in many areas susceptible to extreme storm surge exaggerated with sea level rise. Further study of these areas to improve transit infrastructure and evacuation strategies will improve the outcomes of extreme weather events in the future.

Salt marsh resilience to sea-level rise and increased storm intensity

2021 ◽  
Author(s):  
Natascia Pannozzo ◽  
Nicoletta Leonardi ◽  
Iacopo Carnacina ◽  
Rachel Smedley
Keyword(s):  
Salt Marsh ◽  
Sea Level Rise ◽  
Sea Level ◽  
Storm Surge ◽  
Salt Marshes ◽  
Sediment Budget ◽  
Geophysical Research ◽  
Storm Intensity ◽  
Combined Impact ◽  
And Sea Level

<p>Salt marshes are widely recognised as ecosystems with high economic and environmental value. However, it is still unclear how salt marshes will respond to the combined impact of future sea-level rise and possible increases in storm intensity (Schuerch et al. 2013). This study investigates marsh resilience under the combined impact of various storm surge and sea-level scenarios by using a sediment budget approach. The current paradigm is that a positive sediment budget supports the accretion of salt marshes and, therefore, its survival, while a negative sediment budget causes marsh degradation (Ganju et al. 2015). The Ribble Estuary, North-West England, was used as test case, and the hydrodynamic model Delft3D was used to simulate the response of the salt marsh system to the above scenarios. We conclude that the resilience of salt marshes and estuarine systems is enhanced under the effect of storm surges, as they promote flood dominance and trigger a net import of sediment.  Conversely, sea-level rise threatens marsh stability, by promoting ebb dominance and triggering a net export of sediment. Ultimately, when storm surge and sea-level scenarios are combined, results show that storms with the highest intensities have the potential to counteract the negative impact of sea-level rise by masking its effects on the sediment budget.</p><p><strong>Acknowledgements</strong></p><p>We acknowledge the support of the School of Environmental Sciences, University of Liverpool.</p><p><strong>References</strong></p><p>Ganju, N.K., Kirwan, M.L., Dickhudt, P.J., Guntenspergen, G.R., Cahoon, D.R. and Kroeger, K.D. 2015. “Sediment transport-based metrics of wetland stability”. Geophysical Research Letters, 42(19), 7992-8000.</p><p>Schuerch, M., Vafeidis, A., Slawig, T. and Temmerman, S. 2013. “Modeling the influence of changing storm patterns on the ability of a salt marsh to keep pace with sea level rise”. Journal of Geophysical Research-Earth Surface, 118(1),<strong> </strong>84-96.</p>

Estimation of increase in storm surge damage due to climate change and sea level rise in the Greater Tokyo area

2015 ◽  
Vol 80 (1) ◽  
pp. 539-565 ◽  
Author(s):  
Sayaka Hoshino ◽  
Miguel Esteban ◽  
Takahito Mikami ◽  
Hiroshi Takagi ◽  
Tomoya Shibayama
Keyword(s):  
Climate Change ◽  
Sea Level Rise ◽  
Sea Level ◽  
Storm Surge ◽  
And Sea Level

scholarly journals Impact Assessment of Storm Surge and Climate Change-Enhanced Sea Level Rise on Atoll Nations: A Case Study of the Tarawa Atoll, Kiribati

2021 ◽  
Vol 7 ◽  
Author(s):  
Audrius Sabūnas ◽  
Takuya Miyashita ◽  
Nobuki Fukui ◽  
Tomoya Shimura ◽  
Nobuhito Mori
Keyword(s):  
Climate Change ◽  
Impact Assessment ◽  
Sea Level Rise ◽  
Sea Level ◽  
Storm Surge ◽  
Social Impact ◽  
Small Island ◽  
Impact Of Climate Change ◽  
Exposed Population ◽  
The Impact

The Pacific region consists of numerous Small Island Developing States (SIDS), one of the most vulnerable to flooding caused by compound effects of sea level rise (SLR) and storms. Nevertheless, individual studies regarding the impact assessment for SIDS, such as the low-lying Kiribati, remain scarce. This study assessed the impact of climate change-induced storm surge and SLR compounding effects on Tarawa, the most populous atoll of Kiribati, the largest coral atoll nation. It projected the impact using a combined dynamic surge and SLR model based on the IPCC AR5 RCP scenarios and 1/100 and 1/50 years return period storm events. This approach allows estimating the inundation scope and the consecutive exposed population by the end of the 21st century. The results of this study show that the pace of SLR is pivotal for Tarawa, as the sea level rise alone can claim more than 50% of the territory and pose a threat to over 60% of the population under the most intense greenhouse gas emissions scenario. Furthermore, most coasts on the lagoon side are particularly vulnerable. In contrast, the contribution of extreme events is generally minimal due to low wind speeds and the absence of tropical cyclones (TC). Despite this, it is clear the compound effects are critical and may inescapably bring drastic changes to the atoll nations by the end of this century. The impact assessment in this study draws attention to the social impact of climate change on SIDS, most notably atoll islands, and evaluates their adaptation potential.

scholarly journals Modelling the influences of climate change-associated sea-level rise and socioeconomic development on future storm surge mortality

2015 ◽  
Vol 134 (3) ◽  
pp. 441-455 ◽  
Author(s):  
Simon J. Lloyd ◽  
R. Sari Kovats ◽  
Zaid Chalabi ◽  
Sally Brown ◽  
Robert J. Nicholls
Keyword(s):  
Climate Change ◽  
Sea Level Rise ◽  
Sea Level ◽  
Storm Surge ◽  
Socioeconomic Development

scholarly journals A Study on Coastal Flooding and Risk Assessment under Climate Change in Mid-Western Coast of Taiwan

2017 ◽  
Author(s):  
Tai-Wen Hsu ◽  
Dong-Sin Shih ◽  
Chi-Yu Li ◽  
Yuan-Jyh Lan ◽  
Yu-Chen Lin
Keyword(s):  
Climate Change ◽  
Risk Assessment ◽  
Sea Level Rise ◽  
Sea Level ◽  
Storm Surge ◽  
Coastal Flooding ◽  
Risk Level ◽  
Western Coast ◽  
Wave Condition ◽  
The Impact

This study integrated coastal-watershed models and combined a risk assessment method to develop a methodology to investigate the impact resulting from coastal disasters under climate change. The mid-western coast of Taiwan suffering from land subsidence was selected as the demonstrative area for the vulnerability analysis based on prediction of sea level rise (SLR), wave run-up, overtopping, and coastal flooding under the scenarios of 2020 to 2039. Database from tidal gauges and satellite images were used to analyze sea level rise using EEMD (Ensemble Empirical Mode Decomposition). Extreme wave condition and storm surge were estimated by numerical simulation using WWM (Wind Wave Model) and POM (Princeton Ocean Model). Coastal inundation was then simulated via WASH123D watershed model. The risk map of study areas based on the analyses of vulnerability and disaster were established using the AHP (Analytic Hierarchy Process) technique. Predictions of sea level rise, the maximum wave condition and storm surge under the scenarios of 2020 to 2039 are presented. The results indicate that the sea level at the mid-western coast of Taiwan will rise in an average of 5.8 cm, equivalent to a rising velocity of 2.8 mm/year. The analysis indicates that Wuqi, Lukang, Mailiao, and Taixi townships are susceptive, low resistant and low resilient, and reaches the high risk level. The assessment provides that important information for making adaption policy in the mid-western coast of Taiwan.

scholarly journals Impact Assessment of Climate Change on Storm Surge and Sea Level Rise Around Viti Levu, Fiji

2020 ◽  
Vol 2 ◽  
Author(s):  
Audrius Sabūnas ◽  
Nobuhito Mori ◽  
Nobuki Fukui ◽  
Takuya Miyashita ◽  
Tomoya Shimura
Keyword(s):  
Climate Change ◽  
Impact Assessment ◽  
Sea Level Rise ◽  
Sea Level ◽  
Storm Surge ◽  
Storm Surges ◽  
Population Exposure ◽  
Coastal Regions ◽  
Inundation Area ◽  
The Impact

Projecting the sea level rise (SLR), storm surges, and related inundation in the Pacific Islands due to climate change is important for assessing the impact of climate change on coastal regions as well as the adaptation of the coastal regions. The compounding effects of storm surges and SLR are one of the major causes of flooding and extreme events; however, a quantitative impact assessment that considers the topographical features of the island has not been properly conducted.Therefore, this study projects the impact of storm surge and SLR due to climate change on Viti Levu, which is the biggest and most populous island in Fiji. The impact of SLR on the inundation in coastal areas was simulated using a dynamic model based on the IPCC SROCC scenarios and the 1/100 years return period storm surge implemented based on the RCP8.5 equivalent scenario. The affected inundation area and population due to storm surges and SLRs are discussed based on the compound effects of SLR and storm surge.Although the contribution of SLR to the inundation area was quite significant, the 1/100 year storm surge increased by 10 to 50% of the inundation area. In addition, a narrow and shallow bay with a flat land area had the largest impact of storm surge inundation. Furthermore, the western wind direction had the most severe storm surge inundation and related population exposure due to the topographic and bathymetric characteristics of Viti Levu Island.

Quantifying vertical deformation of salt marsh substrates and their recovery during and after storm surge inundation

2021 ◽  
Author(s):  
Helen Brooks ◽  
Iris Moeller ◽  
Tom Spencer ◽  
Katherine Royse ◽  
Simon Price ◽  
...  
Keyword(s):  
Ecosystem Services ◽  
Salt Marsh ◽  
Sea Level Rise ◽  
Normal Stress ◽  
Sea Level ◽  
Storm Surge ◽  
Salt Marshes ◽  
Dynamic Responses ◽  
Ecosystem Functions ◽  
Vertical Deformation

<p>Salt marshes are globally-distributed, intertidal wetlands. These wetlands provide vital ecosystem functions (providing habitats, filtering water and attenuating waves and currents) that can translate into valuable ecosystem services. Alongside the existence of suitable horizontal accommodation space, the ability of the salt marsh platform to accrete or increase in elevation at a rate commensurate with current and projected future rates of sea-level rise is critical to ensuring future saltmarsh functioning.</p><p>While several studies have assessed whether marsh surface and subsurface processes can keep pace with sea-level rise, few have measured whether, and to what extent, a marsh substrate may consolidate during a storm surge and whether such deformation is permanent or recoverable. This is of key importance given that the frequency and/or magnitude of storm surges is expected to change over the next few decades in some locations. We apply strictly-controlled oedometer tests to understand the response of salt marsh substrates to an applied normal stress (such as that exerted by a storm surge). We compare sediment samples from Tillingham marsh, eastern England, where the sediment is clay/silt-dominated, to samples from Warton marsh, Morecambe Bay, North West England, where the sediment is sand/silt-dominated.</p><p>This research provides, for the first time, insight into the response of two compositionally-different UK marsh substrates to the application of normal stress, such as that induced by hydrostatic loading during extreme inundation events. We demonstrate that both the expected magnitude of axial displacement and the potential to recover vertical deformation after the event are affected by the particle size distribution and the void ratio, as well as past stress conditions on the marsh (particularly as a result of desiccation). The potential for irrecoverable vertical deformation in response to storm surge loading has not previously been identified in salt marsh studies.</p><p>The results of this research will improve the ability of future models of marsh geomorphological evolution to better represent these dynamic responses and their implications for the provision of ecosystem services. This research also challenges existing studies which often do not fully parameterise these dynamic responses when considering salt marsh morphodynamics.</p>

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