scholarly journals HURRICANE SURGE PROTOTYPE DATA COLLECTION

1984 ◽  
Vol 1 (19) ◽  
pp. 17
Author(s):  
Thomas H. Flor ◽  
Susan C. Scott
Keyword(s):  
Data Collection ◽  
Storm Surge ◽  
Numerical Models ◽  
Full Range ◽  
High Water ◽  
Primary Objective ◽  
Water Levels ◽  
Tropical Storms ◽  
Data Set ◽  
Cooperative Program

Storm surges from hurricanes have even more devastating effects on human lives and property than the high wind velocities associated with such storms. Storm surge forecasts are necessary as a guide for emergency action to prevent disasters due to coastal flooding caused by tropical storms. The design and evaluation of coastal structures are also dependent on estimates of storm surge levels. Several numerical models have been developed that appear to reasonably predict the surge from storms of given size and intensity, but they sometimes differ significantly among themselves. A comprehensive data set is needed to quantitatively evaluate these models. These data will also provide a better understanding of coastal processes during periods of severe wave activity and high water levels, and will better define coastal and inland water elevation time histories, high water marks, and water velocity fields caused by tropical storms and hurricanes. The U. S. Army Engineer Waterways Experiment Station (WES), Coastal Engineering Research Center (CERC), under the sponsorship of the Office Chief of Engineers (OCE), has been involved for several years in a project entitled Hurricane Surge Prototype Data Collection Work Unit, the primary objective of which is to collect such a data set. In addition to the work being performed by CERC personnel, a cooperative program has been established with the Nuclear Regulatory Commission (NRC) and the University of Florida to collect surge data along the coast of Florida. A cooperative program has also been established with the National Ocean Service (NOS) to "harden" tide stations in the Gulf of Mexico and along the Atlantic Coast of Florida to survive hurricane forces and record the full range of anticipated surge levels. This paper describes CERC's long term, ongoing Hurricane Surge Prototype Data Collection project, as well as the data collected.

scholarly journals Storm Surge Assessment Methodology Based on Numerical Modelling

10.29007/hrlw ◽  
2018 ◽  
Author(s):  
Lara Santos ◽  
Mariana Gomes ◽  
Luis Vieira ◽  
José Pinho ◽  
José Antunes Do Carmo
Keyword(s):  
Numerical Modelling ◽  
Storm Surge ◽  
Storm Surges ◽  
High Water ◽  
Automatic Generation ◽  
Water Levels ◽  
Tropical Storms ◽  
Assessment Methodology ◽  
Coastal Zones ◽  
Generation Procedure

Coastal zones face severe weaknesses and high-risk situations due to coastal threats like erosion and storms and due to an increasing intensive occupation. Tropical storms events can contribute to the occurrence of these situations, by causing storm surges with high water levels and, consequently, episodes of waves overtopping and coastal flooding. This work aims to describe a methodology to estimate the storm surge occurrences in the Portuguese coastal zone, recurring to historical tropical storms data that occurred in the vicinity of Portugal and to numerical modeling of its characteristics. Delft3D software together with DelfDashboard tools were applied for the numerical modelling. An automatic generation procedure of storms was implemented based on the few available historical storms data characteristics. Obtained results allows to characterize storm surges along the Portuguese coast, identifying the most vulnerable areas and, consequently contributing for its proper planning and management.

scholarly journals THE MODIFIED COASTAL STORM IMPULSE (COSI) PARAMETER AND QUANTIFICATION OF FRAGILITY CURVES FOR COASTAL DESIGN

2012 ◽  
Vol 1 (33) ◽  
pp. 66 ◽  
Author(s):  
David R. Basco ◽  
Nader Mahmoudpour
Keyword(s):  
Storm Surge ◽  
Fragility Curves ◽  
Systems Design ◽  
Field Research ◽  
Water Levels ◽  
Strength Parameter ◽  
Tropical Storms ◽  
Data Set ◽  
Storm Duration ◽  
The Mean

A coastal storm-strength parameter, the Coastal Storm Impulse (COSI) parameter was introduced at the ICCE 2006 (San Diego) and further discussed in the ICCE 2008 (Hamburg) and ICCE 2010 (Shanghai) proceedings. COSI is based on the conservation of linear, horizontal momentum to combine storm surge, wave dynamics, and currents over the storm duration. Both tropical storms (hurricanes) and extra-tropical storms (low-pressure fronts) can produce similar COSI parameters. Analysis of coastal storms over a 10 year period (1994-2003) of measured data at the Corps of Engineers, Field Research Facility (FRF), Duck, NC showed the need to modify the original method to (1) use the mean, nonlinear wave momentum flux, and (2) use only the spikes in storm surge when elevated water levels are above the mean high water level of the tide. This paper presents the full details of how to calculate the modified COSI parameter; the modified results for the 10-yr Duck data set and suggest possible applications to develop fragility curves for coastal engineering design. Clearly, fragility curves are needed to quantify risk and hence resilience in coastal systems design. The intensity of the “load” or “disturbance”, i.e. the severity of the coastal storm must be quantified to develop fragility curves. Excess water levels (storm surge), wave conditions (height, period, direction) and storm duration all contribute to the intensity of a coastal storm. How to combine these three factors has long been a concern of coastal scientists and engineers.

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 Assessment of the effect of vegetation on the transition of the flood wave using hydraulic 2D models

2018 ◽  
Vol 44 ◽  
pp. 00195
Author(s):  
Krzysztof Wolski ◽  
Tomasz Tyminski ◽  
Pawel B. Dabek
Keyword(s):  
Numerical Models ◽  
High Water ◽  
Water Levels ◽  
Lidar Data ◽  
Direct Impact ◽  
Flood Wave ◽  
Mike Flood ◽  
Flood Model ◽  
Maximum Water ◽  
Flooded Area

In the paper an impact of vegetation accumulation on flood wave transition is presented. The research was conducted with use of the MIKE FLOOD model which combines elements of 1D and 2D numerical models. The study area included a 5.5 km long section of the Bystrzyca River near Wroclaw, Poland. A hydraulic model was constructed, on which the simulation of water transition with the probability of occurrence p = 1% and p = 0.2% was conducted. The simulation was carried out for current bank vegetation conditions determined on the basis of precise LIDAR data and for conditions with no vegetation. In this way, the direct impact of vegetation on flood wave transition was obtained. Acquired results, a decrease in maximum water levels and a reduction of flooded area, show that the hydraulic influence of vegetation on high water bed should not be underestimated.

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 Forecasting Storm Surge and Inundation: Model Validation

2017 ◽  
Vol 32 (6) ◽  
pp. 2045-2063 ◽  
Author(s):  
Jayaram Veeramony ◽  
Andrew Condon ◽  
Maarten van Ormondt
Keyword(s):  
Storm Surge ◽  
Stress Gradient ◽  
Forecast Model ◽  
High Water ◽  
Water Levels ◽  
Ocean Dynamics ◽  
Radiation Stress ◽  
Near Shore ◽  
The Impact ◽  
Inundation Model

Abstract Coastal regions are increasingly vulnerable to damage from storm surge and inundation. Delft3D is used by the Naval Oceanographic Office to model the ocean dynamics in the near shore. In this study, the performance of Delft3D in predicting the surge and inundation during Hurricane Ike, which impacted the northern Gulf of Mexico in September 2008, is examined. Wave height, water level, and high-water mark comparisons with a number of observations confirm that the model does well in predicting the surge and inundation during extreme events. The impact of using forecast winds based on the best-track data as opposed to hindcast winds is also investigated, and it is found that the extent of inundation is represented reasonably well with the forecast winds. In Delft3D, waves can be coupled to the hydrodynamic component using the radiation stress gradient method or the dissipation method. Comparing the results of using the two shows that for low-resolution grids such as that needed for a forecast model the dissipation method works better at reproducing the water levels and inundation.

Improved Understanding of Stiffness in Leaf-Type Filament Seals

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Ingo H. J. Jahn ◽  
Gervas Franceschini ◽  
Andrew K. Owen ◽  
Terry V. Jones ◽  
David R. H. Gillespie
Keyword(s):  
Numerical Models ◽  
Full Range ◽  
Operating Conditions ◽  
Negative Stiffness ◽  
Qualitative Assessment ◽  
Aerodynamic Forces ◽  
Data Set ◽  
Leaf Pack ◽  
Stiffness Reduction ◽  
Insight Into

Filament seals, such as brush seals and leaf seals, are investigated as a potential improved seal for gas turbine applications. As these seals operate in contact with the rotor, a good understanding of their stiffness is required in order to minimize seal wear and degradation. This paper demonstrates that the filament and complete seal stiffness is affected in comparable magnitudes by mechanical and aerodynamic forces. In certain cases, the aerodynamic forces can also lead to an overall negative seal stiffness which may affect stable seal operation. In negative stiffness, the displacement of the seal or rotor into an eccentric position causes a resultant force, which, rather than restoring the rotor to a central position, acts to amplify its displacement. Insight into the forces acting on the seal filaments is gained by investigating a leaf seal, which consists of a pack of thin planar leaves arranged around the rotor, with coverplates on either side of the leaf pack, offset from the pack surfaces. The leaf seal is chosen due to its geometry being more suitable for analysis compared to alternative filament seals such as the brush seal. Data from two experimental campaigns are presented which show a seal exhibiting negative stiffness and a seal exhibiting a stiffness reduction due to aerodynamic effects. An empirical model for the forces acting on leaf filaments is developed based on the experimental data, which allows separation of mechanical and aerodynamic forces. In addition a numerical model is developed to analyze the flow approaching the leaf pack and the interleaf flow, which gives an insight into the causes of the aerodynamic forces. Using the empirical and numerical models together, a full picture of the forces affecting leaf stiffness is created. Validation of the models is achieved by successfully predicting seal stiffness for a further data set across the full range of operating conditions. The understanding of aerodynamic forces and their impact on filament and seal stiffness allows for their consideration in leaf seal design. A qualitative assessment of how they may be used to improve seal operation in filament seals is given.

scholarly journals A MODEL TO SIMULATE BEACH PROFILE EVOLUTION INDUCED BY STORMS

2018 ◽  
pp. 10
Author(s):  
Jie Zhang ◽  
Magnus Larson ◽  
Zhenpeng Ge
Keyword(s):  
Sediment Transport ◽  
Numerical Models ◽  
Model Development ◽  
High Water ◽  
Water Levels ◽  
Evolution Model ◽  
Beach Erosion ◽  
Beach Profile ◽  
Dune Erosion ◽  
Profile Change

Beach profile change induced by storms is a common and complex process in coastal engineering. Storms often bring high water levels and large waves, which erode the berm and dune, carrying large quantities of sand offshore, often causing severe damage to coastal properties. Thus, considerable research has been carried out to determine storm impact. Early studies mainly focused on laboratory investigations and analysis of field data. Since the 1980’s, many engineering numerical models of beach profile change have been developed. Kriebel and Dean (1985) proposed a model (EBEACH) to simulate the beach profile evolution with focus on dune erosion during storms, using the concept of an equilibrium beach profile (EBP). However, features such as bars and berms are not described in this model. Larson and Kraus (1989) developed an empirically based model (SBEACH) for describing the formation of bars and berms, also applying the EBP concept. Steetzel (1990) developed a model for cross-shore transport during severe storms that focuses on offshore transport and erosion. Johnson et al. (2012) developed a CS profile evolution model, CSHORE, that is mainly used to predict beach erosion under the combined effect of waves and currents. Although the model provided satisfactory performance in simulating measured berm and dune erosion in field applications, further improvements in dealing with the sediment transport in the intermittently wet-dry areas are desirable. At present, XBeach proposed by Roelvink et al. (2009) is the most popular and widely used model together with SBEACH. Although the objective of the XBeach model is to predict the profile evolution along the entire profile, i.e., both in the subaerial and subaqueous regions, the processes in the former region are less well described from a physics point of view compared to the latter. The response of the subaerial region in XBeach, including the foreshore, berm, and dune, relies on rather ad-hoc empirical sediment transport formulations. This study presents a profile evolution model that is based on the work by Larson et al. (2015). The emphasis of the model development is physically based descriptions of the subaerial profile response induced by storms. Focus of the model validation here is the berm and foreshore region.

scholarly journals NUMERICAL STORM SURGE FORECASTING

1978 ◽  
Vol 1 (16) ◽  
pp. 56
Author(s):  
Manfred Engel
Keyword(s):  
Storm Surge ◽  
North Sea ◽  
Numerical Models ◽  
Meteorological Data ◽  
Atmospheric Model ◽  
Water Levels ◽  
Pressure Gradients ◽  
Practical Applications ◽  
The North ◽  
The North Sea

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.

scholarly journals EVALUATION OF DESIGN WATER LEVELS AT THE EMS-DOLLARD ESTUARY CONSIDERING THE EFFECT OF A STORM SURGE BARRIER

2011 ◽  
Vol 1 (32) ◽  
pp. 43 ◽  
Author(s):  
Gerald Herrling ◽  
Heiko Knaack ◽  
Ralf Kaiser ◽  
Hanz Dieter Niemeyer
Keyword(s):  
Boundary Conditions ◽  
Water Level ◽  
Storm Surge ◽  
Safety Margin ◽  
Storm Surges ◽  
High Water ◽  
Water Levels ◽  
Meteorological Model ◽  
Area Of Interest ◽  
Wind Velocities

In the Ems-Dollard estuary at the southern North Sea coast a revaluation of design water levels along the German dykes has become necessary, since the safety margin for sea level rise was increased by 25 cm due to a decision of the Lower Saxon Ministry for Environment and Climate Protection. The upstream part of the estuary is protected against high storm surges by a storm surge barrier. The closure of the barrier effects downstream surge water levels due to partial reflection. Deterministic-mathematical modeling is applied to evaluate design water levels and design wave run-up. Three severe storm surge events have been hindcasted by a cascade of three hierarchical models from the Continental Shelf over the German Bight into the area of interest. The models are forced by non-stationary and spatially varying data of atmospheric pressure, wind velocities and directions available of meteorological model investigations. The verification of the storm surge model with water level observations yields good agreements. With respect to legal boundary conditions, the single-value-method is applied to determine the highest expected high water level at Emden. Starting from this target water level, the wind velocities in the meteorological boundary conditions are increased with the aim to increase the surge level at the coast and to match the predetermined design water level at Emden. The responding water levels in the Ems-Dollard estuary assign the new design water levels.

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