scholarly journals ADAPTATION PATHWAY FOR A BARRIER ISLAND TO FUTURE HURRICANES

Author(s):  
Stephanie Smallegan ◽  
Evan Mazur

The numerical model XBeach is used to simulate hydrodynamics and morphological change of Bay Head, NJ, which is located on a developed barrier island. Bay Head is fronted with a seawall buried beneath its dunes, and the seawall has been shown to mitigate damage due to storm surge and waves during Hurricane Sandy (2012). The objective of this study is to re-evaluate the effectiveness of the seawall in mitigating damage from a synthetic storm and sea level rise, and refine an adaptation pathway previously created for Bay Head. Utilizing the wave and surge data generated from the North Atlantic Coast Comprehensive Study, synthetic Storm 391 is simulated using XBeach. Model results show the seawall is overtopped by storm surge and waves, causing overwash and reducing dune heights. As sea levels rise, the backbarrier region of the barrier island is severely eroded and the seawall acts as a barrier preventing elevated bay water levels from freely flowing across the island and into the ocean, exacerbating sediment transport on the backbarrier. To fully evaluate the capabilities and limitations of the seawall in mitigating storm damage, additional synthetic storms need to be simulated and the results re-evaluated. This will, in turn, lead to a comprehensive, more robust adaptation pathway for Bay Head.

2021 ◽  
Author(s):  
Martin A. Kress ◽  
Samuel J. Weintraub

The purpose of this Coastal and Hydraulics Engineering technical note (CHETN) is to describe how historic Automatic Identification System (AIS) vessel position data were used to identify a design vessel for use in a storm surge barrier design study. Specifically, this CHETN describes how the AIS data were accessed, how the universe of vessel data was refined to allow for design vessel selection, and how that selection was used in a storm surge barrier (SSB) study. This CHETN draws upon the New Jersey Back Bays Coastal Storm Risk Management Feasibility Study (USACE-NAP 2019), specifically the Appendix B.2 Engineering Appendix Civil document1. The New Jersey Back Bays Study itself builds upon the work of the North Atlantic Coast Comprehensive Study (NACCS) initiated after Hurricane Sandy in 2012 (USACE 2015a).


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Benjamin H. Strauss ◽  
Philip M. Orton ◽  
Klaus Bittermann ◽  
Maya K. Buchanan ◽  
Daniel M. Gilford ◽  
...  

AbstractIn 2012, Hurricane Sandy hit the East Coast of the United States, creating widespread coastal flooding and over $60 billion in reported economic damage. The potential influence of climate change on the storm itself has been debated, but sea level rise driven by anthropogenic climate change more clearly contributed to damages. To quantify this effect, here we simulate water levels and damage both as they occurred and as they would have occurred across a range of lower sea levels corresponding to different estimates of attributable sea level rise. We find that approximately $8.1B ($4.7B–$14.0B, 5th–95th percentiles) of Sandy’s damages are attributable to climate-mediated anthropogenic sea level rise, as is extension of the flood area to affect 71 (40–131) thousand additional people. The same general approach demonstrated here may be applied to impact assessments for other past and future coastal storms.


2021 ◽  
Author(s):  
Elin Andrée ◽  
Jian Su ◽  
Martin Drews ◽  
Morten Andreas Dahl Larsen ◽  
Asger Bendix Hansen ◽  
...  

<p>The potential impacts of extreme sea level events are becoming more apparent to the public and policy makers alike. As the magnitude of these events are expected to increase due to climate change, and increased coastal urbanization results in ever increasing stakes in the coastal zones, the need for risk assessments is growing too.</p><p>The physical conditions that generate extreme sea levels are highly dependent on site specific conditions, such as bathymetry, tidal regime, wind fetch and the shape of the coastline. For a low-lying country like Denmark, which consists of a peninsula and islands that partition off the semi-enclosed Baltic Sea from the North Sea, a better understanding of how the local sea level responds to wind forcing is urgently called for.</p><p>We here present a map for Denmark that shows the most efficient wind directions for generating extreme sea levels, for a total of 70 locations distributed all over the country’s coastlines. The maps are produced by conducting simulations with a high resolution, 3D-ocean model, which is used for operational storm surge modelling at the Danish Meteorological Institute. We force the model with idealized wind fields that maintain a fixed wind speed and wind direction over the entire model domain. Simulations are conducted for one wind speed and one wind direction at a time, generating ensembles of a set of wind directions for a fixed wind speed, as well as a set of wind speeds for a fixed wind direction, respectively.</p><p>For each wind direction, we find that the maximum water level at a given location increases linearly with the wind speed, and the slope values show clear spatial patterns, for example distinguishing the Danish southern North Sea coast from the central or northern North Sea Coast. The slope values are highest along the southwestern North Sea coast, where the passage of North Atlantic low pressure systems over the shallow North Sea, as well as the large tidal range, result in a much larger range of variability than in the more sheltered Inner Danish Waters. However, in our simulations the large fetch of the Baltic Sea, in combination with the funneling effect of the Danish Straits, result in almost as high water levels as along the North Sea coast.</p><p>Although the wind forcing is completely synthetic with no spatial and temporal structure of a real storm, this idealized approach allows us to systematically investigate the sea level response at the boundaries of what is physically plausible. We evaluate the results from these simulations by comparison to peak water levels from a 58 year long, high resolution ocean hindcast, with promising agreement.</p>


Author(s):  
Rachel Housego ◽  
Britt Raubenheimer ◽  
Steve Elgar ◽  
Levi Gorrell ◽  
Heidi Wadman ◽  
...  

Storms can have long-term impacts on the groundwater flows and subsurface salinity structure in coastal aquifers. Previous studies have shown that tides, wave driven infiltration, and storm surge elevate the groundwater level within the beach (Nielsen 1999, Cartwright 2004). The resulting bulge of high groundwater propagates inland, and may cause flooding up to several days after a storm has passed (Gallien 2016). In addition, waves, tides, and storm surge force saltwater to infiltrate into the aquifer above the fresher terrestrial groundwater, and storm-driven pulses of salinity may persist for months (Robinson et al. 2014). Here, observations of groundwater heads and salinities collected continuously for three years are used to examine the effects of ocean storms, wind-driven fluctuations in sound water levels, and morphological changes on a barrier island aquifer.


2011 ◽  
Vol 1 (8) ◽  
pp. 32
Author(s):  
M.P. O'Brien ◽  
J.W. Johnson

As far back as 1635, records show that the East Coast of the United States has repeatedly suffered from severe storm damage (McAleer , 1962). Most of these storms appear to have been of the hurricane type. Such storms generally form in the Atlantic to the east of the Bahama Islands and move eastward and then turn northward to sweep along the Atlantic Coast line (Fig. 1). Along the southern part of the Atlantic Coast the hurricanes move relatively slowly; damage results principally from flooding caused by direct wind action. North of Cape Hatteras the hurricanes move more rapidly (speeds of 40 to 50 miles per hour) and damage is largely due to sudden flooding from a rapidly moving storm surge (Simpson, 1962). The combination of storm surge, wind-driven water, and storm waves inundating large areas along the coast has on numerous occasions caused great damage and loss of life. The great Atlantic Coast storm of March 1962, however, differed in character from the usual hurricane. It proved to be the most disastrous winter coastal storm on record, causing damage from southern New England to Florida. This storm, of relatively large diameter and having gale force winds, remained nearly stationary off the Coast for almost 36 hours . The size and location of the storm, as further discussed below, was such that persistent strong northeasterly winds blowing over a relatively long fetch raised the spring tides (maximum range) to near-record levels. The tidal flooding which attended this storm was in many ways more disastrous than that which accompanies hurricanes (Cooperman and Rosendal, 1962). The storm surge in tropical cyclones generally recedes rapidly after one or two high tides, but the surge accompanying this storm occurred in many locations on four and five successive high tides .' The great destruction was caused by high waves and breakers superimposed on these high tides.


Atmosphere ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1559
Author(s):  
Halina Kowalewska-Kalkowska

The Odra River mouth area is a region of the Southern Baltic coastal zone especially prone to the influence of storm surges. In the present study, the height and extent of the Baltic storm surges, and temporal offsets of the respective maximum water level occurrences in the Odra River mouth area were explored using cross-correlation, cluster analysis and principal component analysis. The analyses were based on hourly water level readings retrieved from water gauging stations located along the lower Odra reaches and at the coasts of the Szczecin Lagoon and the Pomeranian Bay during storm surge years 2008/2009–2019/2020. The analysis of mutual relationships between water levels during storm surges indicated that the extent of marine influence on the lower Odra River and within the Szczecin Lagoon was variable during the studied surge events, and dependent on meteorological conditions (the strongest during the sustained occurrence of wind blowing from the northern sector), discharge from the Odra River catchment (the strongest at low discharge), ice conditions on the lower Odra (suppressing the storm surge propagation upstream), and general sea level in the Pomeranian Bay (stronger at high sea levels). The strongest correlation between sea levels at Świnoujście and water levels in the Szczecin Lagoon and the lower Odra was found at a 6–7 h offset. The extent of storm surges usually reached 100 km up the lower Odra channels, less frequently reaching 130 km away from the sea.


2010 ◽  
Vol 25 (6) ◽  
pp. 1577-1602 ◽  
Author(s):  
Cristina Forbes ◽  
Richard A. Luettich ◽  
Craig A. Mattocks ◽  
Joannes J. Westerink

Abstract The evolution and convergence of modeled storm surge were examined using a high-resolution implementation of the Advanced Circulation Coastal Ocean and Storm Surge (ADCIRC) model for Hurricane Gustav (2008). The storm surge forecasts were forced using an asymmetric gradient wind model (AWM), directly coupled to ADCIRC at every time step and at every grid node. A total of 20 forecast advisories and best-track data from the National Hurricane Center (NHC) were used as input parameters into the wind model. Differences in maximum surge elevations were evaluated for ensembles comprised of the final 20, 15, 10, and 5 forecast advisories plus the best track. For this particular storm, the final 10–12 forecast advisories, encompassing the last 2.5–3 days of the storm’s lifetime, give a reasonable estimate of the final storm surge and inundation. The results provide a detailed perspective of the variability in the storm surge due to variability in the meteorological forecast and how this changes as the storm approaches landfall. This finding is closely tied to the consistency and accuracy of the NHC storm track forecasts and the predicted landfall location and, therefore, cannot be generalized to all storms in all locations. Nevertheless, this first attempt to translate variability in forecast meteorology into storm surge variability provides useful insights for guiding the potential use of storm surge models for forecast purposes. Model skill was also evaluated for Hurricane Gustav by comparing observed water levels with hindcast modeled water levels forced by river flow, tides, and several sources of wind data. The AWM (which ingested best-track information from NHC) generated winds that were slightly higher than those from NOAA’s Hurricane Research Division (HRD) H*Wind analyses and substantially greater than the North American Mesoscale (NAM) model. Surge obtained using the AWM more closely matched the observed water levels than that computed using H*Wind; however, this may be due to the neglect of the contribution of wave setup to the surge, especially in exposed areas. Several geographically distinct storm surge response regimes, some characterized by multisurge pulses, were identified and described.


2011 ◽  
Vol 1 (32) ◽  
pp. 32
Author(s):  
David R Michalsen ◽  
Steven D Babcock ◽  
Lihwa Lin

The U.S. Army Corps of Engineers, Seattle District has completed a feasibility study and determined barrier island restoration to be the most appropriate long-term coastal flood and storm damage reduction measure for the Shoalwater Indian Reservation. Over the last century, Cape Shoalwater has receded more than 2.8 miles. By 1990, the Shoalwater Reservation’s only remaining protection from storm wave attack was a series of barrier islands fronting Tokeland Peninsula. Extreme water levels coincident with strong winter storms have historically inundated this low lying topography and are responsible for the erosion and overwash of the protective barrier island known as Graveyard Spit. Here a simple risk assessment tool is presented for identifying flood risk to the Shoalwater Reservation infrastructure. Statistical analysis of extreme water levels and numerical modeling is utilized to determine the extent of inundation. From the analysis it was determined 54% of the inventoried infrastructure is at risk during a storm event equivalent to the observed event on March 3, 1999. With the barrier island restoration it was found that this risk is reduced to 7%.


1978 ◽  
Vol 1 (16) ◽  
pp. 56
Author(s):  
Manfred Engel

The present state of the development of an operative storm surge prediction system in Germany is described. It is based on numerical models of the atmosphere and the North Sea. First simulations of the storm surge on Jan. 3, 1976 yield the result, that the observed water levels along the North Sea coasts can be recalculated quite well using a meteorological input derived from observations, Whereas the forecasted water levels, using the predicted geostrophic winds of the atmospheric model, are too low since the pressure gradients are too weak. A series of storm surge recalculations with observed and predicted meteorological data shall answer the question, wether parameter fits, applied to the predicted wind stress, lead to satisfying results, suitable for practical applications.


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