Storm Surge Flooding Research Articles

Assessment of coastal vulnerability to climate change hazards at the regional scale: the case study of the North Adriatic Sea

Abstract. Sea level rise, changes in storms and wave climate as a consequence of global climate change are expected to increase the size and magnitude of flooded and eroding coastal areas, thus having profound impacts on coastal communities and ecosystems. River deltas, beaches, estuaries and lagoons are considered particularly vulnerable to the adverse effects of climate change, which should be studied at the regional/local scale. This paper presents a regional vulnerability assessment (RVA) methodology developed to analyse site-specific spatial information on coastal vulnerability to the envisaged effects of global climate change, and assist coastal communities in operational coastal management and conservation. The main aim of the RVA is to identify key vulnerable receptors (i.e. natural and human ecosystems) in the considered region and localize vulnerable hot spot areas, which could be considered as homogeneous geographic sites for the definition of adaptation strategies. The application of the RVA methodology is based on a heterogeneous subset of bio-geophysical and socio-economic vulnerability indicators (e.g. coastal topography, geomorphology, presence and distribution of vegetation cover, location of artificial protection), which are a measure of the potential harm from a range of climate-related impacts (e.g. sea level rise inundation, storm surge flooding, coastal erosion). Based on a system of numerical weights and scores, the RVA provides relative vulnerability maps that allow to prioritize more vulnerable areas and targets of different climate-related impacts in the examined region and to support the identification of suitable areas for human settlements, infrastructures and economic activities, providing a basis for coastal zoning and land use planning. The implementation, performance and results of the methodology for the coastal area of the North Adriatic Sea (Italy) are fully described in the paper.

Hurricane Katrina Impact on a Leveed Bottomland Hardwood Forest in Louisiana

Human alterations of the environment may interact with natural disturbances to alter the characteristics of biological communities in unexpected ways. I studied vegetation plots in a leveed bottomland hardwood forest at Bayou Sauvage National Wildlife Refuge near New Orleans, LA to determine how Hurricane Katrina affected the woody plant community and the distribution of the invasive Chinese tallow tree (Triadica sebifera). The storm killed approximately 68% of all trees in both overstory and understory and reduced basal area proportionately. Nearly all mortality was due to storm surge flooding, which was trapped for up to 3 wk by levees surrounding the refuge. Mortality was far greater than observed in other recent Gulf hurricanes and was three times higher than in similar forests in the nearby Pearl River basin that were struck by the highest winds from Hurricane Katrina. Flood mortality resulted in reduced community diversity and increased the dominance of the introduced T. sebifera after the storm at the expense of less flood-tolerant native species. The plant community appears likely to shift from a canopy dominated by native species to one dominated by Chinese tallow. This shift appears to be largely an unintended consequence of levee construction, which prevented storm surge from rapidly draining after the hurricane passed. The results suggest that widespread floodplain development may interact with future hurricanes to produce abrupt shifts in plant community composition and function in coastal habitats throughout the southeastern United States.

Comprehensive risk analysis of storm surge flood based on WebGIS

The comprehensive risk analysis of storm surge flood is vital to the safety management of sea embankment, the scientific assessment of storm surge disaster and the improvement of emergent treatment in storm surge hazard. Based on the research of disaster-causing, disaster-pregnant and disaster-bearing factors, the influencing factors of storm surge risk are concluded to be flood natural risk, embankment position, embankment width and height. The membership degree of the factors of storm surge risk is firstly determined by storm surge flood evolution based on WebGIS, and the comprehensive risk membership and risk grade of each influencing factor are obtained. Then the effects of a single factor on comprehensive risk and sensitivity analysis are discussed, and the storm surge flood risk map is obtained. Finally, the storm surge of Tianjin Binhai New Area is taken as a case. The results show that the influencing degree of the factors on the comprehensive risk membership is in decreasing order of flood natural risk, embankment position, embankment width and height. The flood risk map of the case is drawn, which is useful to decrease losses caused by storm surge disaster.

Simulation of water levels and extent of coastal inundation due to a cyclonic storm along the east coast of India

The devastation due to storm surge flooding caused by extreme wind waves generated by the cyclones is a severe apprehension along the coastal regions of India. In order to coexist with nature's destructive forces in any vulnerable coastal areas, numerical ocean models are considered today as an essential tool to predict the sea level rise and associated inland extent of flooding that could be generated by a cyclonic storm crossing any coastal stretch. For this purpose, the advanced 2D depth-integrated (ADCIRC-2DDI) circulation model based on finite-element formulation is configured for the simulation of surges and water levels along the east coast of India. The model is integrated using wind stress forcing, representative of 1989, 1996, and 2000 cyclones, which crossed different parts of the east coast of India. Using the long-term inventory of cyclone database, synthesized tracks are deduced for vulnerable coastal districts of Tamil Nadu. Return periods are also computed for the intensity and frequency of cyclones for each coastal district. Considering the importance of Kalpakkam region, extreme water levels are computed based on a 50-year return period data, for the generation of storm surges, induced water levels, and extent of inland inundation. Based on experimental evidence, it is advocated that this region could be inundated/affected by a storm with a threshold pressure drop of 66 hpa. Also it is noticed that the horizontal extent of inland inundation ranges between 1 and 1.5 km associated with the peak surge. Another severe cyclonic storm in Tamil Nadu (November 2000 cyclone), which made landfall approximately 20 km south of Cuddalore, has been chosen to simulate surges and water levels. Two severe cyclonic storms that hit Andhra coast during 1989 and 1996, which made landfall near Kavali and Kakinada, respectively, are also considered and computed run-up heights and associated water levels. The simulations exhibit a good agreement with available observations from the different sources on storm surges and associated inundation caused by these respective storms. It is believed that this study would help the coastal authorities to develop a short- and long-term disaster management, mitigation plan, and emergency response in the event of storm surge flooding. Language: en

Effect of sea level extremes on the western Basque coast during the 21st century

CR Climate Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials CR 51:237-248 (2012) - DOI: https://doi.org/10.3354/cr01069 Effect of sea level extremes on the western Basque coast during the 21st century Marta Marcos1,*, Guillem Chust2, Gabriel Jordà1, Ainhoa Caballero3 1Mediterranean Institute for Advanced Studies (IMEDEA–UIB-CSIC), Miquel Marquès 21, 07190 Esporles, Spain 2AZTI-Tecnalia, Marine Research Division, Txatxarramendi ugartea z/g, 48395 Sukarrieta, Spain 3AZTI-Tecnalia, Marine Research Division, Herrera kaia portualdea z/g, 20110 Pasaia, Spain *Email: marta.marcos@uib.es ABSTRACT: Rising global sea level increases the vulnerability of coastal regions to storm surge flooding. The impact of extreme high waters resulting from the combination of tidal oscillations and changes in mean sea level and in storm surges during the 21st century has been explored in the Bizkaian coast (northern Spain). Mean sea level variations due to temperature changes were estimated from an ensemble mean of global atmosphere-ocean general circulation models in the Bay of Biscay under A1B and A2 climate change scenarios. Changes in the frequency and intensity of storm surges were obtained from the output of a barotropic regional ocean model forced by greenhouse gas concentrations during 2000−2100. The storm surge model was calibrated using available tide gauge observations. Based on the above estimations, return levels of total sea level extremes are expected to increase by up to 40 cm with respect to present-day values. The likely impacts of resulting floods on coastal and estuarine habitats of the Bizkaian coast were assessed applying the return levels to a high precision light detection and ranging (LiDAR) based Digital Terrain Model. Results show that during the second half of the 21st century up to 202 ha are under risk of flooding, of which 50% correspond to urbanized land including industrial and residential areas. This represents a more than 3-fold increase compared to the area at risk from present sea level extremes. This study provides insight into both regional sea level variability and local flood-risks, and thus provides inputs for the formulation of effective mid-term adaptation measures to sea level extremes. KEY WORDS: Sea level · Extremes · Climate change · Storm surges · LiDAR · Coastal impacts Full text in pdf format PreviousNextCite this article as: Marcos M, Chust G, Jordà G, Caballero A (2012) Effect of sea level extremes on the western Basque coast during the 21st century. Clim Res 51:237-248. https://doi.org/10.3354/cr01069 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in CR Vol. 51, No. 3. Online publication date: March 20, 2012 Print ISSN: 0936-577X; Online ISSN: 1616-1572 Copyright © 2012 Inter-Research.

Dynamical suppression of sea level rise along the Pacific coast of North America: Indications for imminent acceleration

Long‐term changes in global mean sea level (MSL) rise have important practical implications for shoreline and beach erosion, coastal wetlands inundation, storm surge flooding, and coastal development. Altimetry since 1993 indicates that global MSL rise has increased about 50% above the 20th century rise rate, from 2 to 3 mm yr−1. At the same time, both tide gauge measurements and altimetry indicate virtually no increase along the Pacific coast of North America during the satellite epoch. Here we show that the dynamical steric response of North Pacific eastern boundary ocean circulation to a dramatic change in wind stress curl, τxy, which occurred after the mid‐1970s regime shift, can account for the suppression of regional sea level rise along this coast since 1980. Alarmingly, mean τxy over the North Pacific recently reached levels not observed since before the mid‐1970s regime shift. This change in wind stress patterns may be foreshadowing a Pacific Decadal Oscillation regime shift, causing an associated persistent change in basin‐scale τxy that may result in a concomitant resumption of sea level rise along the U.S. West Coast to global or even higher rates.

Hurricane preparedness as anticipatory adaptation: A case study of community businesses

This paper examines adaptation to current storm surge flood risk as one indicator of anticipatory adaptation to climate change impacts. Focusing on community businesses, a web-based survey obtained information on hurricane preparedness and risk perceptions in Sarasota County, Florida. A model of current precautionary action that utilized previously identified business characteristics predictive of business preparedness and post-disaster recovery, a spatial variable indicating storm surge exposure, and items measuring the risk perception and information-seeking behavior of business owners explained a majority of the variance in current levels of preparedness. Use of online risk information sources and the geographic distribution of customers and were the strongest predictors of preparedness. Results indicate that the adaptive capacity of businesses may vary significantly with types of businesses, locations, and socio-cognitive characteristics of business owners. To encourage overall community resilience, risk communication efforts should be targeted based on specific elements that predict business preparedness.

Barrier Island Population along the U.S. Atlantic and Gulf Coasts

Barrier islands, the dominant geomorphic features along the U.S. Atlantic and Gulf Coasts, are a favorite place for living and visiting. Unfortunately, barrier islands are vulnerable to storm-surge flooding and erosion because of low elevations and the movement of sand by waves and tides. In order to estimate the impacts of surge flooding, sea-level rise, and erosion on barrier islands, the lengths and areas of barrier islands and population living there were quantified using high-resolution satellite imagery from Google Earth and 1990–2000 census block data. The total length and area of barrier islands spanning 18 states along the U.S. Atlantic and Gulf Coasts are about 3700 km and 6800 km2, respectively. There are approximately 1.4 million people living on barrier islands, half of which are in Florida according to 2000 census data. The population densities of barrier islands are three times those of coastal states on average, and the population increased 14% from 1990 to 2000. The collision course of population increases and development in the face of accelerated sea-level rise due to global climate change makes barrier islands more vulnerable.

Monitoring Duration and Extent of Storm-Surge and Flooding in Western Coastal Louisiana Marshes With Envisat ASAR Data

Inundation maps of coastal marshes in western Louisiana were created with multitemporal Envisat Advanced Synthetic Aperture (ASAR) scenes collected before and during the three months after Hurricane Rita landfall in September 2005. Corroborated by inland water-levels, 7 days after landfall, 48% of coastal estuarine and palustrine marshes remained inundated by storm-surge waters. Forty-five days after landfall, storm-surge inundated 20% of those marshes. The end of the storm-surge flooding was marked by an abrupt decrease in water levels following the passage of a storm front and persistent offshore winds. A complementary dramatic decrease in flood extent was confirmed by an ASAR-derived inundation map. In nonimpounded marshes at elevations ;80 cm during the first month after Rita landfall. After this initial period, drainage from marshes-especially impounded marshes-was hastened by the onset of offshore winds. Following the abrupt drops in inland water levels and flood extent, rainfall events coinciding with increased water levels were recorded as inundation re-expansion. This postsurge flooding decreased until only isolated impounded and palustrine marshes remained inundated. Changing flood extents were correlated to inland water levels and largely occurred within the same marsh regions. Trends related to incremental threshold increases used in the ASAR change-detection analyses seemed related to the preceding hydraulic and hydrologic events, and VV and HH threshold differences supported their relationship to the overall wetland hydraulic condition.

Modeling Extreme Rainfall, Winds, and Surge from Hurricane Isabel (2003)

Abstract Landfalling tropical cyclones present major hazards for the eastern United States. Hurricane Isabel (September 2003) produced more than $3.3 billion in damages from wind, inland riverine flooding, and storm surge flooding, and resulted in 17 fatalities. Case study analyses of Hurricane Isabel are carried out to investigate multiple hazards from landfalling tropical cyclones. The analyses focus on storm evolution following landfall and center on simulations using the Weather Research and Forecasting Model (WRF). WRF simulations are coupled with the 2D, depth-averaged hydrodynamic Advanced Circulation Model (ADCIRC), to examine storm surge in the Chesapeake Bay. Analyses of heavy rainfall and flooding include an examination of the structure and evolution of extreme rainfall over land. Intercomparisons of simulated rainfall from WRF with Hydro-NEXRAD rainfall fields and observations from rain gauge networks are presented. A particular focus of these analyses is the evolving distribution of rainfall, relative to the center of circulation, as the storm moves over land. Similar analyses are carried out for the wind field of Hurricane Isabel as it moves over the mid-Atlantic region. Outer rainbands, which are not well captured in WRF simulations, played a major role in urban flooding and wind damage, especially for the Baltimore metropolitan region. Wind maxima in outer rainbands may also have played a role in storm surge flooding in the upper Chesapeake Bay.

Two mechanisms of aquatic and terrestrial habitat change along an Alaskan Arctic coastline

Arctic habitats at the interface between land and sea are particularly vulnerable to climate change. The northern Teshekpuk Lake Special Area (N-TLSA), a coastal plain ecosystem along the Beaufort Sea in northern Alaska, provides habitat for migratory waterbirds, caribou, and potentially, denning polar bears. The 60-km coastline of N-TLSA is experiencing increasing rates of coastline erosion and storm surge flooding far inland resulting in lake drainage and conversion of freshwater lakes to estuaries. These physical mechanisms are affecting upland tundra as well. To better understand how these processes are affecting habitat, we analyzed long-term observational records coupled with recent short-term monitoring. Nearly the entire coastline has accelerating rates of erosion ranging from 6 m/year from 1955 to 1979 and most recently peaking at 17 m/year from 2007 to 2009, yet an intensive monitoring site along a higher bluff (3–6 masl) suggested high interannual variability. The frequency and magnitude of storm events appears to be increasing along this coastline and these patterns correspond to a greater number of lake tapping and flooding events since 2000. For the entire N-TLSA, we estimate that 6% of the landscape consists of salt-burned tundra, while 41% is prone to storm surge flooding. This offset may indicate the relative frequency of low-magnitude flood events along the coastal fringe. Monitoring of coastline lakes confirms that moderate westerly storms create extensive flooding, while easterly storms have negligible effects on lakes and low-lying tundra. This study of two interacting physical mechanisms, coastal erosion and storm surge flooding, provides an important example of the complexities and data needs for predicting habitat change and biological responses along Arctic land–ocean interfaces.

Offshore transport of sediment during cyclonic storms: Hurricane Ike (2008), Texas Gulf Coast, USA

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Identifying the Economic Effects of Salt Water Intrusion after Hurricane Katrina

Hurricane Katrina made landfall August 29, 2005 becoming the costliest and one of the deadliest hurricanes in U.S. history. Katrina caused widespread loss of life, with over 700 bodies recovered in New Orleans by October 23, 2005. Before Hurricane Katrina, the region supported approximately one million non-farm jobs, with 600,000 of them in New Orleans. The ecological consequences were considerable including storm surge floods into coastal areas. These ecological impacts are still being felt throughout the region through human-driven coastal erosion and saltwater intrusion—issues that have long been damaging the region's natural storm buffers—were made worse by the hurricane. Specifically this research will: (1) provide current updates of the economic and ecological impacts from Katrina (2) review the current literature relating to salt water intrusion and (3) identify the economic impact of salt water erosion from hurricane Katrina.

Storm surge modelling for the Bay of Bengal and Arabian Sea

Most of the countries around the North Indian Ocean are threatened by storm surges associated with severe tropical cyclones. The destruction due to the storm surge flooding is a serious concern along the coastal regions of India, Bangladesh, Myanmar, Pakistan, Sri Lanka, and Oman. Storm surges cause heavy loss of lives and property damage to the coastal structures and losses of agriculture which lead to annual economic losses in these countries. About 300,000 lives were lost in one of the most severe cyclones that hit Bangladesh (then East Pakistan) in November 1970. The Andhra Cyclone devastated part of the eastern coast of India, killing about 10,000 persons in November 1977. More recently, the Chittagong cyclone of April 1991 killed 140,000 people in Bangladesh, and the Orissa coast of India was struck by a severe cyclonic storm in October 1999, killing more than 15,000 people besides enormous loss to the property in the region. These and most of the world’s greatest natural disasters associated with the tropical cyclones have been directly attributed to storm surges. The main objective of this article is to highlight the recent developments in storm surge prediction in the Bay of Bengal and the Arabian Sea.

Impacts of climate change and sea-level rise on cyclonic storm surge floods in Bangladesh

This paper describes the impacts of sea surface temperature (SST) rise and sea-level rise (SLR) on cyclonic storm surge flooding in western Bangladesh. A calibrated numerical hydrodynamic model was used to simulate surge wave propagation through the rivers and overland flooding. The model was calibrated with base condition (present climate), and then eight flooding scenarios of plausible future conditions were assessed by considering increased surge heights. Flooded area, flooding depth and surge intrusion length were computed by superimposing the predicted maximum water level information on a digital elevation model (DEM). This analysis showed that for a storm surge under 2 °C SST rise and 0.3 m SLR, flood risk area would be 15.3% greater than the present risk area and depth of flooding would increase by as much as 22.7% within 20 km from the coastline. Within the risk area, the study identified 5690 km 2 land (22% of exposed coast) as a high-risk zone (HRZ) where flooding of depth 1 m or more might occur, and people should move to nearby cyclone shelters during extreme cyclonic events. Predicted area of HRZ is 1.26 times the currently demarcated HRZ. It was estimated that 320 additional shelters are required to accommodate people in the newly identified HRZ. This information would be of value to policy and decision makers for future shelter planning and designing shelter heights.

Hurricane Katrina Storm Surge Reconnaissance

Hurricane Katrina (August 23–30, 2005) was one of the costliest and deadliest hurricanes to ever strike the United States, impacting low-lying coastal plains particularly vulnerable to storm surge flooding. Maximum storm surges, overland flow depths, and inundation distances were measured along the Gulf Coast of Florida, Alabama, Mississippi, and Louisiana. The vehicle-based survey was complemented by inspections with the reconnaissance boat along the Gulf Coast and the Mississippi Barrier Islands. The survey covered both the impact on the built and the natural environments. The storm surge peaked to the east of Katrina’s path exceeding 10m in several locations along the Mississippi coastline. The storm surge measurements show that the lower floors of specially designed buildings were damaged by the surge of seawater and associated wave action, while the upper floors sustained minimal wind damage. The storm surge measurements along New Orleans Lakeshore allowed the investigators to exclude overtopping as failure mechanism for the 17th Street outfall canal levee. Hurricane Katrina’s storm surge distribution (Category 3 at landfall) is compared against Hurricane Camille’s storm surge distribution (Category 5 at landfall). The land loss on the barrier islands and the increased vulnerability of the US Gulf Coast to future hurricane storm surges is discussed.

Climate change and coastal flooding in Metro Boston: impacts and adaptation strategies

Sea level rise (SLR) due to climate change will increase storm surge height along the 825 km long coastline of Metro Boston, USA. Land at risk consists of urban waterfront with piers and armoring, residential areas with and without seawalls and revetments, and undeveloped land with either rock coasts or gently sloping beachfront and low-lying coastal marshes. Risk-based analysis shows that the cumulative 100 year economic impacts on developed areas from increased storm surge flooding depend heavily upon the adaptation response, location, and estimated sea level rise. Generally it is found that it is advantageous to use expensive structural protection in areas that are highly developed and less structural approaches such as floodproofing and limiting or removing development in less developed or environmentally sensitive areas.

Comparison of the CEST and SLOSH Models for Storm Surge Flooding

The Coastal and Estuarine Storm Tide (CEST) model for the boundary-fitted curvilinear grid has been developed recently to simulate a hurricane-induced storm surge. A new wetting-drying algorithm was based on accumulated volume and was created for simulating overland flooding. To evaluate the capability of the CEST model, it was compared with the well-established storm surge model—Sea, Lake, and Overland Surge from Hurricane (SLOSH)—in model grid representation and surge inundation prediction. Two models were compared: first, by carrying out storm surge simulations for Hurricanes Andrew (1992), Hugo (1989), and Camille (1969) over SLOSH's coarse polar grids with cell sizes of 500–7000 m. Results show that the CEST model agreed better with field observations of storm surge flooding. The CEST model was further evaluated by applying it to a fine-resolution curvilinear grid, which has cell sizes of 100–200 m at the hurricane landfall area, along with a superior representation of coastal topography. Comparison of the model results with field-measured elevations of high water marks and the locations of debris lines indicated that the CEST model, with the use of a fine-resolution grid, greatly reduced the uncertainty in computing storm surge flooding.

A Factorial Analysis of Storm Surge Flooding in Barrow, Alaska

Abstract This paper describes work to improve the understanding of the broad range of factors affecting the occurrence of flooding in Barrow, Alaska, using as a basis the series of extreme events that have affected the community over the past 50 years. A numerical weather prediction model and a storm surge inundation model have been applied to the 21 case studies identified in National Weather Service data as high wind events. Based on this simulation work flow, a reduced-form model that adequately describes the flooding response has been developed. Specifically, it was found that when wind is forecast to be greater than 13 m s−1 (30 mph) for at least 20 h, this is the most accurate predictor of the possibility of damaging flood. It was found that wind direction, the magnitude of fetch to the sea ice edge (when present), and maximum wind speed were in contrast relatively small contributors to the likelihood of flooding.

Numerical modeling of tide-surge interaction along Orissa coast of India

The Orissa coast of India is one of the most vulnerable regions of extreme sea levels associated with severe tropical cyclones. There was extensive loss of life and property due to the October 1999 super cyclone, which devastated large part of the Orissa coast. The shallow nature of the head bay, presence of a large number of deltas formed by major rivers of Orissa such as Mahanadi and Dhamra, and high tidal range are responsible for storm surge flooding in the region. Specifically, rising and falling tidal phases influence the height, duration, and arrival time of peak surge along the coast. The objective of the present study is to evaluate the tide-surge interaction during the 1999 Orissa cyclone by using nonlinear vertically integrated numerical models. The pure tidal solution for the head bay region of the Bay of Bengal provides the initial condition for the fine resolution nested grid Orissa model. However, the feedback from the Orissa model does not affect the head bay model as the study provides a one-way interaction. Numerical experiments are performed to study the tide-surge interaction by considering various relative phases of the tidal waves with the surge-wave produced by 1999 Orissa cyclone. The comparison, although utilizing only the limited estimates of tidal data, appears adequate to assert that the principal features are reproduced correctly.