scholarly journals Projecting the effects of land subsidence and sea level rise on storm surge flooding in Coastal North Carolina

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jeremy Johnston ◽  
Felicio Cassalho ◽  
Tyler Miesse ◽  
Celso M. Ferreira

AbstractMuch of the United States Atlantic coastline continues to undergo subsidence due to post glacial settlement and ground water depletion. Combined with eustatic sea level rise (SLR), this contributes to an increased rate of relative SLR. In this work, we utilize the ADvanced CIRCulation model to project storm surges across coastal North Carolina. Recent hurricanes Irene and Matthew are simulated considering SLR and subsidence estimates for 2100. Relative to present day conditions, storm surge susceptible regions increase by 27% (Irene) to 40% (Matthew) due to subsidence. Combined with SLR (+ 74 cm), results suggest more than a doubling of areal flood extent for Irene and more than a three-fold increase for Hurricane Matthew. Considering current regional population distributions, this translates to an increase in at-risk populations of 18% to 61% due to subsidence. Even further, exposed populations are projected to swell relative to Matthew and Irene baseline simulations (8200 and 28,500) by more than 70,000 in all SLR scenarios (79,400 to 133,600). While increases in surge inundation are driven primarily by SLR in the region, there remains a substantial contribution due to vertical land movement. This outlines the importance of exploring spatially variable land movement in surge prediction, independent of SLR.

2021 ◽  
Author(s):  
Jeremy Johnston ◽  
Felicio Cassalho ◽  
Tyler Miesse ◽  
Celso Ferreira

Abstract Much of the United States Atlantic coastline continues to subside due to post glacial settlement and ground water depletion. Combined with sea level rise (SLR), this contributes to a larger relative rate of SLR regionwide. In this work, we utilize the ADvanced CIRCulation model to simulate storm surges across coastal North Carolina. Simulations of recent Hurricanes Irene (2011) and Matthew (2016) are performed considering SLR projections and land subsidence estimates for the year 2100. The model is validated against historic water level observations with generally strong agreement (mean R2 0.81, RMSE 10–31 cm). At current rates of subsidence, storm surge susceptible regions increase on the order of 30–40% by 2100 relative to near-present day conditions. Flood water redistribution leaves low-lying areas especially vulnerable, as many of which also experience increased land subsidence. Combined with SLR projections, results project more than a doubling of areal flood extent for Hurricane Irene from ~ 2,000 km2 (2011) to 5,000 km2 (2100, subsidence + 74 cm), and more than a 3-fold increase ~ 1,400 km2 (2016) to 4,900 km2 (2100, subsidence + 74 cm) for Hurricane Matthew. The expected inundation increases have substantial implications for communities and ecosystems located in coastal North Carolina.


2020 ◽  
Vol 33 (9) ◽  
pp. 3745-3769 ◽  
Author(s):  
Jianjun Yin ◽  
Stephen M. Griffies ◽  
Michael Winton ◽  
Ming Zhao ◽  
Laure Zanna

AbstractStorm surge and coastal flooding caused by tropical cyclones (hurricanes) and extratropical cyclones (nor’easters) pose a threat to communities along the Atlantic coast of the United States. Climate change and sea level rise are altering the statistics of these extreme events in a rather complex fashion. Here we use a fully coupled global weather/climate modeling system (GFDL CM4) to study characteristics of extreme daily sea level (ESL) along the U.S. Atlantic coast and their response to global warming. We find that under natural weather processes, the Gulf of Mexico coast is most vulnerable to storm surge and related ESL. New Orleans is a striking hotspot with the highest surge efficiency in response to storm winds. Under a 1% per year atmospheric CO2 increase on centennial time scales, the anthropogenic signal in ESL is robust along the U.S. East Coast. It can emerge from the background variability as soon as in 20 years, or even before global sea level rise is taken into account. The regional dynamic sea level rise induced by the weakening of the Atlantic meridional overturning circulation facilitates this early emergence, especially during wintertime coastal flooding associated with nor’easters. Along the Gulf Coast, ESL is sensitive to the modification of hurricane characteristics under the CO2 forcing.


2015 ◽  
Vol 7 (2) ◽  
pp. 118-132
Author(s):  
Yosuke Adachi

Abstract Sea level rise (SLR) is a topic of increasing importance, as global warming continues to drive it at the global level and other factors such as land subsidence also affect it at the local level. Economic and human-based approaches have been taken to assess its impact on society. However, quantifications of the effect of SLR on mortality have not been extensive. Therefore, the objective of this study is to quantify the relative impact of SLR on mortality due to extreme coastal flooding for 2011–2100. First, an empirical relationship between annual storm surges caused by tropical cyclones (TCs) and associated fatalities is established. Next, a conceptual framework is introduced to measure rises in sea level due to gradual SLR and temporary storm surges on a common scale called cumulatively raised sea level. An analysis applying SLR projections to this framework shows that, in addition to the deaths that occur because of coastal flooding due to TCs, at least 84–139 deaths due to extra coastal flooding caused by SLR may occur in the United States by 2100, in the absence of coastal population changes, adaptation, and protection failure. Higher-than-expected rates of SLR due to increased discharge from polar glaciers will raise this estimate to 277. Protection failure will also result in more fatalities. Conversely, adaptation, even when combined with coastal population increases, may lead to fewer fatalities.


2017 ◽  
Author(s):  
Mathew Hauer

Many sea level rise assessments focus on populations presently inhabiting vulnerable coastal communities, but to date no studies have attempted to model the destinations of these potentially displaced persons. With millions of potential future migrants in heavily populated coastal communities, sea level rise scholarship focusing solely on coastal communities characterizes sea level rise as primarily a coastal issue, obscuring the potential impacts in landlocked communities created by sea level rise induced displacement. Here I address this issue by merging projected populations at-risk of sea level rise with migration systems simulations to project future destinations of sea level rise migrants in the United States (U.S.). I find that unmitigated sea level rise is expected to reshape the U.S. population distribution, potentially stressing landlocked areas unprepared to accommodate this wave of coastal migrants -- even after accounting for potential adaptation. These results provide the first glimpse of how climate change will reshape future population distributions and establishes a new foundation for modelling potential migration destinations from climate stressors in an era of global environmental change.


2019 ◽  
Author(s):  
Amir Hossein Mahdavi ◽  
Hamid Ansari Sharghi

Storm surge is generated by the integration of waves, tide and wind setup that is resulted in unwanted mean sea level rise and coastal flooding. The estimation of accurate storm surge is essential for the engineering design of coastal structures. In this study, we estimated the respond of mean sea level winds, tide, waves, and sea-level rise using a local coastal model. A fully coupled hydrodynamic and wave model was implemented to obtain storm surge from different phenomena. The simulations of water level fluctuations due to these parameters were analyzed with the wind forces identified with tidal observations in the Port of Kong. Extreme value analysis was performed to determine the fluctuations associated with different return periods. These data were combined by sea-level rise projections are combined with resulted value. The worst and best scenario of storm surges for each return period were determined for engineering design purposes.


Author(s):  
Paul Chinowsky ◽  
Jacob Helman

The national study analyzes sea level rise (SLR) impacts based on 36 different SLR and storm surge scenarios across 5.7 million geographic locations and 3 time periods. Taking an approach based on engineering design guidelines and current cost estimates, the study details projected cost impacts for states, counties, and cities. These impacts are presented from multiple perspectives including total cost, cost per-capita, and cost per-square mile. The purpose of the study is to identify specific locations where infrastructure is vulnerable to rising sea levels. The study finds that Sea Level Rise (SLR) and minimal storm surge is a $400 billion threat to the United States by 2040 that includes a need for at least 50,000 miles of protective barriers. The research is limited in its scope to protecting coastal infrastructure with sea walls. Additional methods exist and may be appropriate in individual situations. The study is original in that it is a national effort to identify infrastructure that is vulnerable as well as the cost associated with protecting this infrastructure.


2018 ◽  
Vol 52 (2) ◽  
pp. 92-105 ◽  
Author(s):  
Luca Castrucci ◽  
Navid Tahvildari

AbstractHampton Roads is a populated area in the United States Mid-Atlantic region that is highly affected by sea level rise (SLR). The transportation infrastructure in the region is increasingly disrupted by storm surge and even minor flooding events. The purpose of this study is to improve our understanding of SLR impacts on storm surge flooding in the region. We develop a hydrodynamic model to study the vulnerability of several critical flood-prone neighborhoods to storm surge flooding under several SLR projections. The hydrodynamic model is validated for tide prediction, and its performance in storm surge simulation is validated with the water level data from Hurricane Irene (2011). The developed model is then applied to three urban flooding hotspots located in Norfolk, Chesapeake, and the Isle of Wight. The extent, intensity, and duration of storm surge inundation under different SLR scenarios are estimated. Furthermore, the difference between the extent of flooding as predicted by the hydrodynamic model and the “bathtub” approach is highlighted.


2021 ◽  
Author(s):  
Davide Tognin ◽  
Andrea D'Alpaos ◽  
Marco Marani ◽  
Luca Carniello

<p>Coastal wetlands lie at the interface between submerged and emerged environments and therefore represent unique yet delicate ecosystems. Their existence, resulting from complex interactions between hydrodynamics and sediment dynamics, is challenged by increasing rates of sea-level rise, lowered fluvial sediment input as well as an increasing anthropogenic pressure. The future survival of these peculiar morphologies is becoming even more complicated, because of the construction and planning of coastal defence structures designed to protect urban areas from flooding. Important examples are the flood protection systems built to protect New Orleans (USA), the river Scheldt Estuary (The Netherlands) and Venice (Italy). In this context, understanding the physical processes on which coastal marshes are grounded and how engineering measures can alter them is of extreme importance in order to plan conservation interventions.</p><p>To understand marsh sedimentation dynamics in flood-regulated environments, we investigated through field observations and modelling the effect of the storm-surge barrier designed to protect the city of Venice, the so-called Mo.S.E. system, which has in fact become operational since October 2020.</p><p>Sedimentation measurements in different salt marshes of the Venice lagoon carried out in the period October 2018-October 2020 show that more than 70% of yearly sedimentation accumulates during storm-surge conditions, despite their short duration. Moreover, the sedimentation rate displays a highly non-linear increase with marsh inundation intensity, due to the interplay between higher water levels and greater suspended sediment concentration. Barrier operations during storm surges to avoid flooding of urban areas will reduce water levels and marsh inundation. Therefore, we computed sedimentation in a flood-regulated scenario for the same observation period, using the relation we obtained between tidal forcing and sedimentation rate. Our results show that some occasional closures during intense storm surges (70 hours/year on average) suffice to reduce the yearly sedimentation of the same order of magnitude of the relative sea-level rise rate experienced by the Venice lagoon during the last century (2.5 mm/y).</p><p>We conclude that storm-surge barrier operations can dangerously reduce salt-marsh vertical accretion rate, thus challenging wetland survival in face of increasing sea-level rise.</p>


Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3538
Author(s):  
Andre de Souza de Lima ◽  
Arslaan Khalid ◽  
Tyler Will Miesse ◽  
Felicio Cassalho ◽  
Celso Ferreira ◽  
...  

The Southern Brazilian Coast is highly susceptible to storm surges that often lead to coastal flooding and erosive processes, significantly impacting coastal communities. In addition, climate change is expected to result in expressive increases in wave heights due to more intense and frequent storms, which, in conjunction with sea-level rise (SLR), has the potential to exacerbate the impact of storm surges on coastal communities. The ability to predict and simulate such events provides a powerful tool for coastal risk reduction and adaptation. In this context, this study aims to investigate how accurately storm surge events can be simulated in the Southwest Atlantic Ocean employing the coupled ADCIRC+SWAN hydrodynamic and phase-averaged wave numerical modeling framework given the significant data scarcity constraints of the region. The model’s total water level (TWL) and significant wave height (Hs) outputs, driven by different sources of meteorological forcing, i.e., the Fifth Generation of ECMWF Atmospheric Reanalysis (ERA 5), the Climate Forecast System Version 2 (CFSv2), and the Global Forecast System (GFS), were validated for three recent storm events that affected the coast (2016, 2017, and 2019). In order to assess the potentially increasing storm surge impacts due to sea-level rise, a case study was implemented to locally evaluate the modeling approach using the most accurate model setup for two 2100 SLR projections (RCP 4.5 and 8.5). Despite a TWL underestimation in all sets of simulations, the CFSv2 model stood out as the most consistent meteorological forcing for the hindcasting of the storm surge and waves in the numerical model, with an RMSE range varying from 0.19 m to 0.37 m, and an RMSE of 0.56 m for Hs during the most significant event. ERA5 was highlighted as the second most accurate meteorological forcing, while adequately simulating the peak timings. The SLR study case demonstrated a possible increase of up to 82% in the TWL during the same event. Despite the limitations imposed by the lack of continuous and densely distributed observational data, as well as up to date topobathymetric datasets, the proposed framework was capable of expanding TWL and Hs information, previously available for a handful of gauge stations, to a spatially distributed and temporally unlimited scale. This more comprehensive understanding of such extreme events represents valuable knowledge for the potential implementation of more adequate coastal management and engineering practices for the Brazilian coastal zone, especially under changing climate conditions.


2020 ◽  
Vol 8 (9) ◽  
pp. 725
Author(s):  
Ziyu Chen ◽  
Philip Orton ◽  
Thomas Wahl

Gated storm surge barriers are being studied by the United States Army Corps of Engineers (USACE) for coastal storm risk management for the New York City metropolitan area. Surge barrier gates are only closed when storm tides exceeding a specific “trigger” water level might occur in a storm. Gate closure frequency and duration both strongly influence the physical and environmental effects on enclosed estuaries. In this paper, we use historical observations to represent future storm tide hazard, and we superimpose local relative sea-level rise (SLR) to study the potential future changes to closure frequency and duration. We account for the effects of forecast uncertainty on closures, using a relationship between past storm surge and forecast uncertainty from an operational ensemble forecast system. A concern during a storm surge is that closed gates will trap river streamflow and could cause a new problem with trapped river water flooding. Similarly, we evaluate this possibility using historical data to represent river flood hazard, complemented by hydrodynamic model simulations to capture how waters rise when a hypothetical barrier is closed. The results show that SLR causes an exponential increase of the gate closure frequency, a lengthening of the closure duration, and a rising probability of trapped river water flooding. The USACE has proposed to prevent these SLR-driven increases by periodically raising the trigger water level (e.g., to match a prescribed storm return period). However, this alternative management approach for dealing with SLR requires waterfront seawalls to be raised at a high, and ongoing, additional future expense. For seawalls, costs and benefits will likely need to be weighed on a neighborhood-by-neighborhood basis, and in some cases retreat or other non-structural options may be preferable.


Sign in / Sign up

Export Citation Format

Share Document