Geomorphic changes measured on Dauphin Island, AL, during Hurricane Nate

Shore & Beach ◽  
2019 ◽  
pp. 16-22
Author(s):  
Jeffrey Coogan ◽  
Bret Webb ◽  
Stephanie Smallegan ◽  
Jack Puleo
Keyword(s):  
Water Level ◽  
Storm Surge ◽  
Barrier Island ◽  
Water Levels ◽  
Time Varying ◽  
Empirical Estimates ◽  
Water And Sediment ◽  
Island System ◽  
Level Sensors

Storm surge and waves from Hurricane Nate in 2017 resulted in large overwash and inundation regions on Dauphin Island, Alabama. The overwash event consisted of the transport of water and sediment over the beach, dune, and barrier island system. Seven transects were established to measure pre- and post-storm survey profiles. Nine wave and water level sensors were deployed in an overwash region and captured the overwash conditions including time-varying water levels and waves. All transects experienced a net loss of sediment from the subaerial region surveyed and a range of inundation and sediment overwash. The results highlight the limits of empirical estimates for evaluating the exposure of backdune regions to overwash and inundation.

scholarly journals ADAPTATION PATHWAY FOR A BARRIER ISLAND TO FUTURE HURRICANES

2018 ◽  
pp. 52
Author(s):  
Stephanie Smallegan ◽  
Evan Mazur
Keyword(s):  
Storm Surge ◽  
Atlantic Coast ◽  
Barrier Island ◽  
Hurricane Sandy ◽  
Water Levels ◽  
Storm Damage ◽  
Sea Levels ◽  
The North ◽  
Adaptation Pathway ◽  
Comprehensive Study

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.

Precise ground-based GNSS-reflectometry water level measurements using multiple low-cost antennas

2020 ◽  
Author(s):  
David Purnell ◽  
Natalya Gomez ◽  
William Minarik ◽  
Gregory Langston
Keyword(s):  
Water Level ◽  
Low Cost ◽  
Multiple Antennas ◽  
Random Noise ◽  
Water Levels ◽  
Tropospheric Delay ◽  
Sources Of Error ◽  
Gnss Reflectometry ◽  
Water Level Measurements ◽  
Level Sensors

<p>GNSS-Reflectometry (GNSS-R) is a promising new technique to monitor water levels due to easier and cheaper installation of instruments in remote environments compared to traditional acoustic sensors or pressure gauges. GNSS stations that have been used for reflectometry purposes thus far are designed for monitoring land motion and may cost more than 10,000 USD each. We have found that a low-cost GNSS antenna and receiver (10 USD) can be used to make equally precise water level measurements, with an RMSE of a few centimeters when compared to a collocated acoustic sensor. However, an RMSE of less than one centimeter is typical for water level sensors and this level of accuracy is desired for research purposes. Two of the dominant sources of error in GNSS-R measurements are the effects of random noise in the Signal-to-Noise Ratio (SNR) data and tropospheric delay. Modelling work suggests that these sources of error can be reduced by using multiple low-cost antennas in the same location. In light of this, we have installed an experimental setup of antennas at various locations along the Saint Lawrence River and Initial results show that multiple antennas can be used to provide more precise measurements than a single antenna. Our installations of multiple antennas are less than 5% of the cost of stations that have been used in previous GNSS-R literature. Hence this approach could be applied to install a dense network of water level sensors along rivers, lakes or coastlines at a relatively low cost. We expect that this approach could also be applied to GNSS-R soil moisture or snow depth measurements.</p>

Uncertainty in coastal flooding: modelling and visualisation

2020 ◽  
Author(s):  
John Maskell
Keyword(s):  
Water Level ◽  
Storm Surge ◽  
Return Period ◽  
Flood Risk ◽  
High Water ◽  
Coastal Flooding ◽  
Water Levels ◽  
Tidal Range ◽  
The Uk ◽  
Flood Maps

<p>Two case studies are considered in the UK, where uncertainty and drivers of coastal flood risk are explored through modelling and visualisations. Visualising the impact of uncertainty is a useful way of explaining the potential range of predicted or simulated flood risk to both expert and non-expert stakeholders.</p><p>Significant flooding occurred in December 2013 and January 2017 at Hornsea on the UK East Coast, where storm surge levels and waves overtopped the town’s coastal defences. Uncertainty in the potential coastal flooding is visualised at Hornsea due to the range of uncertainty in the 100-year return period water level and in the calculated overtopping due to 3 m waves at the defences. The range of uncertainty in the simulated flooding is visualised through flood maps, where various combinations of the uncertainties decrease or increase the simulated inundated area by 58% and 82% respectively.</p><p>Located at the mouth of the Mersey Estuary and facing the Irish Sea, New Brighton is affected by a large tidal range with potential storm surge and large waves. Uncertainty in the coastal flooding at the 100-year return period due to the combination of water levels and waves is explored through Monte-Carlo analysis and hydrodynamic modelling. Visualisation through flood maps shows that the inundation extent at New Brighton varies significantly for combined wave and surge events with a joint probability of 100 years, where the total flooded area ranges from 0 m<sup>2</sup> to 10,300 m<sup>2</sup>. Waves are an important flood mechanism at New Brighton but are dependent on high water levels to impact the coastal defences and reduce the effective freeboard. The combination of waves and high-water levels at this return level not only determine the magnitude of the flood extent but also the spatial characteristics of the risk, whereby flooding of residential properties is dominated by overflow from high water levels, and commercial and leisure properties are affected by large waves that occur when the water level is relatively high at the defences.</p>

scholarly journals WAVE MODELING WITH SWAN+ADCIRC FOR THE SOUTH CAROLINA COASTAL STORM SURGE STUDY

2012 ◽  
Vol 1 (33) ◽  
pp. 48
Author(s):  
Christopher Bender ◽  
William Miller ◽  
Ashley Naimaster ◽  
Tucker Mahoney
Keyword(s):  
South Carolina ◽  
Water Level ◽  
Storm Surge ◽  
Water Levels ◽  
The South ◽  
Wave Parameters ◽  
Water Level Changes ◽  
Tightly Coupled ◽  
Wave Induced ◽  
Adcirc Model

The South Carolina Surge Study (SCSS) used the tightly coupled SWAN+ADCIRC model to simulate tropical storm surge events. The tightly coupled model allowed calculation of wave-induced water level changes within the storm surge simulations. Inclusion of the wave-induced water level changes represents a more physics-based approach than previous methods that added wave setup after model simulations ended. Development of the SWAN+ADCIRC model included validation of water levels to local tidal forcing and for three historical hurricanes — Hazel (1954), Hugo (1989), and Ophelia (2005). The validation for waves did not include Hurricane Hazel because measured data was unavailable. Additional comparisons with WAM model results provided supplemental support to the SWAN model results. Model output applied in comparisons included contour plots of maximum wave parameters, time series of wave parameters at selected locations, and wave spectra.

scholarly journals BARRIER ISLAND GROUNDWATER

2018 ◽  
pp. 10
Author(s):  
Rachel Housego ◽  
Britt Raubenheimer ◽  
Steve Elgar ◽  
Levi Gorrell ◽  
Heidi Wadman ◽  
...  
Keyword(s):  
Storm Surge ◽  
Groundwater Level ◽  
Coastal Aquifers ◽  
Morphological Changes ◽  
Barrier Island ◽  
Water Levels ◽  
Salinity Structure

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.

scholarly journals STORM SURGE FORECASTING METHODS IN ENCLOSED SEAS

1978 ◽  
Vol 1 (16) ◽  
pp. 58
Author(s):  
P.F. Hamblin
Keyword(s):  
Water Level ◽  
Storm Surge ◽  
Storm Surges ◽  
High Water ◽  
Computational Effort ◽  
Water Levels ◽  
Large Lakes ◽  
Forecasting Methods ◽  
The Stability ◽  
Storm Surge Forecasting

Storm surges in enclosed seas although generally not as large in amplitude as their oceanic counterparts are nonetheless of considerable importance when low lying shoreline profiles, shallow water depth, and favourable geographical orientation to storm winds occur together. High water may result in shoreline innundation and in enhanced shoreline erosion. Conversely low water levels are hazardous to navigation. The purpose of this paper is to discuss the problem of storm surge forecasting in enclosed basins with emphasis on automated operational procedures. In general, operational forecasting methods must be based on standard forecast parameters, require a minimum of computational effort in the preparation of the forecast, must be applicable to lakes of different geometry and to any point on the shore, and to be able to resolve water level changes on an hourly basis to 10 cm in the case of high water level excursions associated with large lakes and less than that for smaller lakes. Particular physical effects arising in lakes which make these constraints difficult to fulfill are the reflections of resurgences of water levels arising from lateral boundaries, the stability of the atmospheric boundary layer and the presence of such subsynoptic disturbances as squall lines and travelling pressure jumps.

scholarly journals Storm-Surge Induced Water Level Changes in the Odra River Mouth Area (Southern Baltic Coast)

Atmosphere ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1559
Author(s):  
Halina Kowalewska-Kalkowska
Keyword(s):  
Water Level ◽  
Storm Surge ◽  
River Mouth ◽  
Storm Surges ◽  
Mouth Area ◽  
Water Levels ◽  
Szczecin Lagoon ◽  
Sea Levels ◽  
River Mouth Area ◽  
Odra River

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.

scholarly journals INVESTIGATION OF WAVE INDUCED STORM SURGE WITHIN A LARGE COASTAL EMBAYMENT - MORETON BAY (AUSTRALIA)

2011 ◽  
Vol 1 (32) ◽  
pp. 22 ◽  
Author(s):  
Philip Treloar ◽  
David Taylor ◽  
Paul Prenzler
Keyword(s):  
Water Level ◽  
Tropical Cyclones ◽  
Storm Surge ◽  
Wave Model ◽  
Water Levels ◽  
Residual Water ◽  
Storm Tide ◽  
Moreton Bay ◽  
Coastal Embayment ◽  
Set Up

Moreton Bay is a large coastal embayment on the south-east Queensland coast which is surrounded by the urbanised areas of greater Brisbane on its western and southern shorelines. It is protected from the open coast by a number of islands, including South Stradbroke, North Stradbroke and Moreton Islands. Tropical cyclones occasionally track far enough south to cause significant damage to south-east Queensland due to flooding, winds, waves and elevated ocean water levels. Distant tropical cyclones which may be several hundred kilometres north of Moreton Bay have been known to cause storm surge, high waves and erosion inside Moreton Bay. These events generally do not generate gale force winds within Moreton Bay, but can generate large ocean swell waves. It has been identified that the wave conditions generated from distant cyclones can cause a variation in water levels inside Moreton Bay. A detailed study was undertaken to investigate the regional wave set-up process which affects Moreton Bay. The simulation of the residual water levels within Moreton Bay using a coupled hydrodynamic and wave model system developed for this study is considerably more accurate than applying a hydrodynamic model alone and explains water level anomalies that have a tidal frequency. The paper discusses the physical process of regional wave set-up inside a large embayment, analysis of observed residual water level and also the modelling study undertaken to quantify the influence of waves on storm tide levels inside Moreton Bay. The storm tide hazard study for the Moreton Bay Councils included the effects of regional wave set-up in the specification of design water levels.

scholarly journals Run-up parameterization and beach vulnerability assessment on a barrier island: a downscaling approach

2016 ◽  
Vol 16 (1) ◽  
pp. 167-180 ◽  
Author(s):  
G. Medellín ◽  
J. A. Brinkkemper ◽  
A. Torres-Freyermuth ◽  
C. M. Appendini ◽  
E. T. Mendoza ◽  
...  
Keyword(s):  
Water Level ◽  
Water Depth ◽  
Shallow Water Equation ◽  
Barrier Island ◽  
Water Levels ◽  
Tidal Level ◽  
Extreme Water Level ◽  
Extreme Water Levels ◽  
Run Up ◽  
Wave Induced

Abstract. We present a downscaling approach for the study of wave-induced extreme water levels at a location on a barrier island in Yucatán (Mexico). Wave information from a 30-year wave hindcast is validated with in situ measurements at 8 m water depth. The maximum dissimilarity algorithm is employed for the selection of 600 representative cases, encompassing different combinations of wave characteristics and tidal level. The selected cases are propagated from 8 m water depth to the shore using the coupling of a third-generation wave model and a phase-resolving non-hydrostatic nonlinear shallow-water equation model. Extreme wave run-up, R2%, is estimated for the simulated cases and can be further employed to reconstruct the 30-year time series using an interpolation algorithm. Downscaling results show run-up saturation during more energetic wave conditions and modulation owing to tides. The latter suggests that the R2% can be parameterized using a hyperbolic-like formulation with dependency on both wave height and tidal level. The new parametric formulation is in agreement with the downscaling results (r2  =  0.78), allowing a fast calculation of wave-induced extreme water levels at this location. Finally, an assessment of beach vulnerability to wave-induced extreme water levels is conducted at the study area by employing the two approaches (reconstruction/parameterization) and a storm impact scale. The 30-year extreme water level hindcast allows the calculation of beach vulnerability as a function of return periods. It is shown that the downscaling-derived parameterization provides reasonable results as compared with the numerical approach. This methodology can be extended to other locations and can be further improved by incorporating the storm surge contributions to the extreme water level.

scholarly journals StormSense: A New Integrated Network of IoT Water Level Sensors in the Smart Cities of Hampton Roads, VA

2018 ◽  
Vol 52 (2) ◽  
pp. 56-67 ◽  
Author(s):  
Jon Derek Loftis ◽  
David Forrest ◽  
Sridhar Katragadda ◽  
Kyle Spencer ◽  
Tammie Organski ◽  
...  
Keyword(s):  
Water Level ◽  
Smart Cities ◽  
Monitoring Network ◽  
Water Levels ◽  
United States Geological Survey ◽  
Integrated Network ◽  
Hampton Roads ◽  
Newport News ◽  
Starting Point ◽  
Level Sensors

AbstractPropagation of cost-effective water level sensors powered through the Internet of Things (IoT) has expanded the available offerings of ingestible data streams at the disposal of modern smart cities. StormSense is an IoT-enabled inundation forecasting research initiative and an active participant in the Global City Teams Challenge, seeking to enhance flood preparedness in the smart cities of Hampton Roads, VA, for flooding resulting from storm surge, rain, and tides. In this study, we present the results of the new StormSense water level sensors to help establish the “regional resilience monitoring network” noted as a key recommendation from the Intergovernmental Pilot Project. To accomplish this, the Commonwealth Center for Recurrent Flooding Resiliency's Tidewatch tidal forecast system is being used as a starting point to integrate the extant (NOAA) and new (United States Geological Survey [USGS] and StormSense) water level sensors throughout the region and demonstrate replicability of the solution across the cities of Newport News, Norfolk, and Virginia Beach within Hampton Roads, VA. StormSense's network employs a mix of ultrasonic and radar remote sensing technologies to record water levels during 2017 Hurricanes Jose and Maria. These data were used to validate the inundation predictions of a street level hydrodynamic model (5-m resolution), whereas the water levels from the sensors and the model were concomitantly validated by a temporary water level sensor deployed by the USGS in the Hague and crowd-sourced GPS maximum flooding extent observations from the sea level rise app, developed in Norfolk, VA.

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