Exposure to Coastal Hazards in a Rapidly Expanding Northern Urban Centre, Iqaluit, Nunavut

ARCTIC ◽  
2015 ◽  
Vol 68 (4) ◽  
pp. 453 ◽  
Author(s):  
Scott V. Hatcher ◽  
Donald L. Forbes
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Critical Infrastructure ◽  
High Water ◽  
Water Levels ◽  
Coastal Hazards ◽  
Tidal Range ◽  
Urban Centre ◽  
Relative Sea Level ◽  
Run Up

 The City of Iqaluit, Nunavut, is an expanding urban centre with important infrastructure located in the coastal zone. This study investigates the exposure of this infrastructure to coastal hazards (rising mean sea level, extreme water levels, wave run-up, and sea ice). Using a coastal digital elevation model, we evaluate the inundation and flooding that may result from projected sea level rise. Some public and private infrastructure is already subject to flooding during extreme high water events. Using a near upper-limit scenario of 0.7 m for relative sea level rise from 2010 to 2100, we estimate that critical infrastructure will have a remaining freeboard of 0.3–0.8 m above high spring tide, and some subsistence infrastructure will be inundated. The large tidal range, limited over-water fetch, and wide intertidal flats reduce the risk of wave impacts. When present, the shorefast ice foot provides protection for coastal infrastructure. The ice-free season has expanded by 1.0–1.5 days per year since 1979, increasing the opportunity for storm-wave generation and thus exposure to wave run-up. Overtopping of critical infrastructure and displacement by flooding of subsistence infrastructure are potential issues requiring better projections of relative sea level change and extreme high water levels. These results can inform decisions on adaptation, providing measurable limits for safe development.

scholarly journals Late-Holocene sea-level reconstruction (1200 BC–AD 100) in the Westergo terp region of the northern Netherlands

2021 ◽  
Vol 100 ◽  
Author(s):  
Peter C. Vos ◽  
Annet Nieuwhof
Keyword(s):  
Salt Marsh ◽  
Sea Level Rise ◽  
Sea Level ◽  
Wadden Sea ◽  
High Water ◽  
Tidal Range ◽  
Tidal Basin ◽  
Northwestern Part ◽  
Archaeological Research ◽  
Relative Sea Level

Abstract In the early 20th century, archaeological research in the terp (artificial dwelling-mound) region of the northern Netherlands focused, besides settlement history, on natural salt-marsh dynamics and sea-level rise. In particular Van Giffen used salt-marsh deposits under dated terp layers to reconstruct the rate of sedimentation of the developing salt marsh and relative sea-level rise. This line of research in archaeology was rekindled during excavations in the terp of Wijnaldum-Tjitsma between 1991 and 1993. Since then, geology has become an integral part of archaeological research in the terp region. This paper focuses on the northwestern part of the province of Friesland (Westergo), where most archaeological terp research during the past three decades has been carried out, owing to several research programmes by the Province of Friesland. The primary aim of the geoarchaeological research is to better understand the interaction between human inhabitants and the salt-marsh landscape. The sedimentary record exposed in the excavation trenches makes it possible to collect data on the development of the coastal environments of the Wadden Sea prior to habitation, including data on sea-level rise. The sea-level data collected in the geoarchaeological studies in Westergo are the topic of this paper. The measured levels of the tidal-flat/salt-marsh boundary underneath the terps make it possible to reconstruct palaeo-Mean High Water (palaeo-MHW) levels. Such sea-level index points (SLIPs), based on marine shell data points from 12 locations, now make it possible to establish a palaeo-MHW diagram for this part of the Wadden Sea, for the period between 1200 BC and AD 100. In this period the palaeo-MHW in the Westergo region rose from c.1.8 m to 0.3 m −NAP: a mean sea-level rise of c.0.12 m per century. We discuss the fact that elevation of the palaeo-MHW SLIP is not only determined by relative sea level (RSL), but also by the magnitude of the tidal amplitude. The tidal range, and therefore the MHW elevations in a tidal basin, can change from place to place and also in time. Also in a single tidal basin the tidal range is variable, due to the distortion of the tidal wave as a result of the morphology of the tidal system. Such local tidal range fluctuations – not related to sea-level rise – influence the palaeo-MHW curve of Westergo and other tidal basins in the Wadden Sea and need to be taken into account when interpreting the curve. In this paper, we will go into the causes of changes in palaeotidal ranges in meso- and macrotidal systems, analyse the tidal range variations in recent and subrecent basins and estuaries and discuss the implications of these changes on the sea-level curve of the Westergo region in NW Friesland.

scholarly journals Quantifying Uncertainty in Exposure to Coastal Hazards Associated with Both Climate Change and Adaptation Strategies: A U.S. Pacific Northwest Alternative Coastal Futures Analysis

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 545
Author(s):  
Alexis K. Mills ◽  
Peter Ruggiero ◽  
John P. Bolte ◽  
Katherine A. Serafin ◽  
Eva Lipiec
Keyword(s):  
Climate Change ◽  
Sea Level Rise ◽  
Sea Level ◽  
Performance Metrics ◽  
Coastal Flooding ◽  
Water Levels ◽  
Coastal Hazards ◽  
Policy Decisions ◽  
Management Decisions ◽  
Quantifying Uncertainty

Coastal communities face heightened risk to coastal flooding and erosion hazards due to sea-level rise, changing storminess patterns, and evolving human development pressures. Incorporating uncertainty associated with both climate change and the range of possible adaptation measures is essential for projecting the evolving exposure to coastal flooding and erosion, as well as associated community vulnerability through time. A spatially explicit agent-based modeling platform, that provides a scenario-based framework for examining interactions between human and natural systems across a landscape, was used in Tillamook County, OR (USA) to explore strategies that may reduce exposure to coastal hazards within the context of climate change. Probabilistic simulations of extreme water levels were used to assess the impacts of variable projections of sea-level rise and storminess both as individual climate drivers and under a range of integrated climate change scenarios through the end of the century. Additionally, policy drivers, modeled both as individual management decisions and as policies integrated within adaptation scenarios, captured variability in possible human response to increased hazards risk. The relative contribution of variability and uncertainty from both climate change and policy decisions was quantified using three stakeholder relevant landscape performance metrics related to flooding, erosion, and recreational beach accessibility. In general, policy decisions introduced greater variability and uncertainty to the impacts of coastal hazards than climate change uncertainty. Quantifying uncertainty across a suite of coproduced performance metrics can help determine the relative impact of management decisions on the adaptive capacity of communities under future climate scenarios.

Assessment of the sensitivity of the southern coast of the Gulf of Corinth (Peloponnese, Greece) to sea-level rise

2012 ◽  
Vol 4 (4) ◽  
Author(s):  
Efthimios Karymbalis ◽  
Christos Chalkias ◽  
George Chalkias ◽  
Eleni Grigoropoulou ◽  
George Manthos ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Tidal Range ◽  
Sensitivity Index ◽  
Southern Coast ◽  
Gis Technology ◽  
Relative Sea Level ◽  
Gulf Of Corinth ◽  
Rise Rate ◽  
Relative Sea Level Rise

AbstractThe eustatic sea-level rise due to global warming is predicted to reach approximately 18–59 cm by the year 2100, which necessitates the identification and protection of sensitive sections of coastline. In this study, the classification of the southern coast of the Gulf of Corinth according to the sensitivity to the anticipated future sealevel rise is attempted by applying the Coastal Sensitivity Index (CSI), with variable ranges specifically modified for the coastal environment of Greece, utilizing GIS technology. The studied coastline has a length of 148 km and is oriented along the WNW-ESE direction. CSI calculation involves the relation of the following physical variables, associated with the sensitivity to long-term sea-level rise, in a quantifiable manner: geomorphology, coastal slope, relative sea-level rise rate, shoreline erosion or accretion rate, mean tidal range and mean wave height. For each variable, a relative risk value is assigned according to the potential magnitude of its contribution to physical changes on the coast as the sea-level rises. Every section of the coastline is assigned a risk ranking based on each variable, and the CSI is calculated as the square root of the product of the ranked variables divided by the total number of variables. Subsequently, a CSI map is produced for the studied coastline. This map showed that an extensive length of the coast (57.0 km, corresponding to 38.7% of the entire coastline) is characterized as highly and very highly sensitive primarily due to the low topography, the presence of erosionsusceptible geological formations and landforms and fast relative sea-level rise rates. Areas of high and very high CSI values host socio-economically important land uses and activities.

scholarly journals An Assessment of Vertical Land Movement to Support Coastal Hazards Planning in Washington State

Water ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 281
Author(s):  
Tyler J. Newton ◽  
Ray Weldon ◽  
Ian M. Miller ◽  
David Schmidt ◽  
Guillaume Mauger ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Tide Gauge ◽  
Puget Sound ◽  
Global Navigation Satellite Systems ◽  
Coastal Hazards ◽  
Cascadia Subduction Zone ◽  
Tide Gauge Records ◽  
Relative Sea Level ◽  
Satellite Systems

The sea and land change elevation spatially and temporally from a multitude of processes, so it is necessary to constrain the movement of both to evaluate how coastlines will evolve and how those evolving coastlines will impact the natural and built environment over time. We combine land movement observations from global navigation satellite systems (GNSSs), leveling of geodetic monuments, and tide gauge records with a tectonic model of the Cascadia subduction zone to constrain absolute rates of vertical land movement in coastal Washington. We infer rates of vertical land movement in areas lacking direct observations by interpolating high-quality land movement observations and a discretely sampled interseismic locking model. Here we present a model of absolute vertical land movement that is combined with sea level rise estimates to inform local relative sea level projections on a community-scale. The most rapid vertical uplift (~3.5 mm/year) of the land is found across the northwest Olympic Peninsula, which currently outpaces sea level rise. Conversely, some areas, including a stretch of the northern Pacific Ocean coast from La Push to Kalaloch and the southern Puget Sound, are found to be subsiding at 0.5–1.0 mm/year, exacerbating the rate of relative sea level rise and thereby increasing the vulnerability of coastal communities.

scholarly journals A global analysis of extreme coastal water levels with implications for potential coastal overtopping

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Rafael Almar ◽  
Roshanka Ranasinghe ◽  
Erwin W. J. Bergsma ◽  
Harold Diaz ◽  
Angelique Melet ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Global Analysis ◽  
Climate Scenario ◽  
Global Scale ◽  
Water Levels ◽  
Coastal Hazards ◽  
Wave Runup ◽  
Anthropogenic Pressures ◽  
Future Assessment

AbstractClimate change and anthropogenic pressures are widely expected to exacerbate coastal hazards such as episodic coastal flooding. This study presents global-scale potential coastal overtopping estimates, which account for not only the effects of sea level rise and storm surge, but also for wave runup at exposed open coasts. Here we find that the globally aggregated annual overtopping hours have increased by almost 50% over the last two decades. A first-pass future assessment indicates that globally aggregated annual overtopping hours will accelerate faster than the global mean sea-level rise itself, with a clearly discernible increase occurring around mid-century regardless of climate scenario. Under RCP 8.5, the globally aggregated annual overtopping hours by the end of the 21st-century is projected to be up to 50 times larger compared to present-day. As sea level continues to rise, more regions around the world are projected to become exposed to coastal overtopping.

Relative sea-level rise during the Main Postglacial Transgression in NE Scotland, U.K.

1999 ◽  
Vol 90 (1) ◽  
pp. 1-27 ◽  
Author(s):  
D. E. Smith ◽  
C. R. Firth ◽  
C. L. Brooks ◽  
M. Robinson ◽  
P. E. F. Collins
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Sea Level Changes ◽  
Relative Sea Level ◽  
Sea Levels ◽  
Relative Sea Level Rise ◽  
The Mean ◽  
Run Up ◽  
Storegga Slide

AbstractFlandrian (Holocene) relative sea level changes in the lower Ythan valley, NE Scotland, U.K., are inferred from detailed stratigraphical evidence including microfossil analysis and radiocarbon assay. The principal event recorded is the Main Postglacial Transgression, which was under way in the area by c. 8300 and had culminated before c. 4000 radiocarbon years BP. It is concluded that the rise in relative sea levels during the transgression in the area exceeded 12 m; that the mean rate of rise there was 8·05 mm a−1 between c. 8300 and c. 7100 radiocarbon years BP, or 7·09 mm a−1 based upon calibrated dates for the same period, before declining markedly to 1·75 mm a−1 (radiocarbon) or 1·86 mm a−1 (calibrated) to the culmination of the event. By comparison with other sites, the culmination appears to have been time-transgressive in eastern Scotland. Deposits of the Second Storegga Slide tsunami, which occurred during the Main Postglacial Transgression, are present in the Ythan valley, where the sediment run-up of the event at the sites studied is estimated to have been within the range 2·99–5·19 m.

scholarly journals ASSESSING NON-LINEAR RESPONSE IN EXTREME COASTAL WATER LEVELS

2018 ◽  
pp. 62
Author(s):  
Betsy Hicks ◽  
Emily Dhingra ◽  
Brian Batten ◽  
Alaurah Moss ◽  
Tucker Mahoney ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Water Levels ◽  
Coastal Hazards ◽  
Flood Insurance ◽  
Flood Hazards ◽  
Change Analysis ◽  
Approximate Methods ◽  
Coastal Flood ◽  
Non Linear

Rising sea levels and the resultant amplification of flood frequencies and magnitude has the potential to significantly change coastal flood hazards over the coming century. The Federal Emergency Management Agency (FEMA) has recognized the potential future implications of Sea Level Rise (SLR) on coastal hazards and flood insurance. However, at present, FEMA does not incorporate future conditions information in to their regulatory or non-regulatory products in the framework of their National Flood Insurance Program. Many other programs that create products to support risk recognition and resilient planning are based on “bathtub” approaches (for example NOAA’s Sea Level Rise Viewer: https://coast.noaa.gov /digitalcoast/tools/slr). In order to better understand non-linear changes in coastal flood hazards, due to increased water depth and wave heights, or in the surge propagation pathway, FEMA has funded a series of pilot studies. For this study an end-of-the-century SLR condition has been imposed on storm surge simulations in West Florida to gain further understanding into how SLR may modify surge and wave effects, as well as potential techniques for approximating these via efficient approximate methods. Both the detailed nonlinear methods and approximate linear approaches for developing SLR advisory information will be evaluated and compared for this study. A second, mid-century SLR condition was utilized for a shoreline change analysis to evaluate how recession due to SLR may affect coastal flood hazards.

scholarly journals New Estimation of the Post Little Ice Age Relative Sea Level Rise

Geosciences ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 348 ◽  
Author(s):  
Vincenzo Pascucci ◽  
Gabriela Frulio ◽  
Stefano Andreucci
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Little Ice Age ◽  
Ice Age ◽  
Tidal Range ◽  
Relative Sea Level ◽  
Geotechnical Characteristics ◽  
Relative Sea Level Rise ◽  
The City ◽  
New Buildings

The study area is located in NW Sardinia Island (Italy), Mediterranean Sea. Sardinia is considered stable since the late Pliocene with a negligible subsidence of about 0.01 mm/y. It is therefore normally used to reconstruct the Pleistocene and Holocene sea level curves. Our research focusses on the sea-facing city of Alghero that from 1353 to 1720 was under the Spanish government. During this time, the city was renovated and new buildings edified. Dimension stones were quarried all around Alghero both in the nearby inland and along the coast. Coastal quarries were considered the most suitable for both rock quality and the easiest way to transport the quarried material by boat. The quarried rocks are late Pleistocene dune and beach sandstones deposited from the 132 ka (Marine Isotopic Stage—MIS5) to about 65 ka (MIS4). Sandstones crop out from few cm to 3 m above the present sea level and underwent several consolidation processes related to loading and marine weathering. This latter favoured dissolution and circulation of calcium carbonate which cemented the rocks. It is reported that the Spanish were looking for these “marine” sandstones for their high geotechnical characteristics. Different rules were adopted through time for the size of the dimension stones and this has allowed us to establish a quarry exploitation chronology. For example, “40 × 60 × 20” cm was the size of the dimension stones used for the Alghero Cathedral dated at 1505–1593. Nowadays most of the coastal Spanish quarry floors are 30 centimetres below mean sea level (tidal range is 30 cm). Accordingly, we infer that relative sea level from 1830 AD (and of the Little Ice Age) rose in about 200 years to the present level at the rate of about 1.4 mm/y. Considering that relative sea level rise during the Medieval warm period was of 0.6 mm/y over a period of about 400 years, we may deduce that human influence was strong enough to lead to a relative sea-level rise faster and in shorter time.

scholarly journals Exploring the partial use of the Mo.S.E. system as effective adaptation to rising flood frequency of Venice

2021 ◽  
Vol 21 (12) ◽  
pp. 3629-3644
Author(s):  
Riccardo A. Mel
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Venice Lagoon ◽  
Flood Frequency ◽  
Tidal Range ◽  
Relative Sea Level ◽  
Relative Sea Level Rise ◽  
Set Up ◽  
Flooding Events ◽  
The Impact

Abstract. The Venice lagoon (Italy) is particularly vulnerable to the impact of subsidence and sea level rise driven by climate change. Some structural measures have been adopted over time to protect Venice from flooding, among which a system of flap gates (Experimental Electromechanical Module, Mo.S.E., system) has been operational in the testing phase since October 2020. However, relative sea level rise and wind set-up pose relevant management challenges, as a frequent closing of the lagoon would have negative impacts on flushing capacity, the fishing industry, and port activities. Here, the focus is on the hydrodynamic effects of a partial closure of the Mo.S.E. barriers that, compared to closing all the three inlets of the lagoon, could play a role in reducing the economic and environmental impacts of the Mo.S.E. system. The main goal is to identify the flooding events that can be counteracted by closing only the Lido inlet, which is the closest to the city of Venice. Based on the tidal and meteorological dataset collected in the period 2000–2019, a robust modelling exercise identifies a linear relationship between tidal range and reduction of the sea level peaks, which results in the protection of all urban settlements within the lagoon from two-thirds of the flooding events up to a relative sea level rise of +0.4 m.

Submergence, nutrient enrichment, and tropical storm impacts on Spartina alterniflora in the microtidal northern Gulf of Mexico

2020 ◽  
Vol 644 ◽  
pp. 33-45
Author(s):  
JM Hill ◽  
PS Petraitis ◽  
KL Heck
Keyword(s):  
Gulf Of Mexico ◽  
Sea Level Rise ◽  
Sea Level ◽  
Spartina Alterniflora ◽  
Anthropogenic Impacts ◽  
Interactive Effects ◽  
Relative Sea Level ◽  
Hurricane Disturbance ◽  
Submergence Stress ◽  
Relative Sea Level Rise

Salt marshes face chronic anthropogenic impacts such as relative sea level rise and eutrophication, as well as acute disturbances from tropical storms that can affect the productivity of these important communities. However, it is not well understood how marshes already subjected to eutrophication and sea level rise will respond to added effects of episodic storms such as hurricanes. We examined the interactive effects of nutrient addition, sea level rise, and a hurricane on the growth, biomass accumulation, and resilience of the saltmarsh cordgrass Spartina alterniflora in the Gulf of Mexico. In a microtidal marsh, we manipulated nutrient levels and submergence using marsh organs in which cordgrasses were planted at differing intertidal elevations and measured the impacts of Hurricane Isaac, which occurred during the experiment. Prior to the hurricane, grasses at intermediate and high elevations increased in abundance. After the hurricane, all treatments lost approximately 50% of their shoots, demonstrating that added nutrients and elevation did not provide resistance to hurricane disturbance. At the end of the experiment, only the highest elevations had been resilient to the hurricane, with increased above- and belowground growth. Added nutrients provided a modest increase in above- and belowground growth, but only at the highest elevations, suggesting that only elevation will enhance resilience to hurricane disturbance. These results empirically demonstrate that S. alterniflora in microtidal locations already subjected to submergence stress is less able to recover from storm disturbance and suggests we may be underestimating the loss of northern Gulf Coast marshes due to relative sea level rise.

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