Solutions to Coastal Disasters '02

A conceptual framework based on probabilistic risk analysis (PRA) is proposed for the design of coastal flood defences which meets the sustainability requirements. The overall framework includes the management of the remaining risk as an integral part of the design process. The implementation of the risk analysis requires (i) the prediction of the flood risk, (ii) the evaluation of the acceptable flood risk and (iii) the evaluation of the flood risk level which is obtained through comparison of the predicted and acceptable flood risk.

A set of scenarios is developed based on decision-theoretic models from finance that represent the dynamics of the decision-state facing a planner concerning coastal hazard management. These scenarios illustrate why risk factors are important in the decision-making process and how they can be incorporated into decision models. The exercise potentially suggests improvements and refinements to presently used Cost-Benefit Analysis procedures allowing for a greater range of risk and uncertainty, and offers new tools that can aid in decisions concerning provision of shoreline stabilization. The outcomes of these scenarios justify better planning and control of existing and future building, and that of post-storm policies. Lastly, these models allow us to explore the range of our understanding of coastal processes and interactions with shoreline stabilization projects, and can identify new and useful data needed in coastal management and hazard management decisions.

Numerical modeling tools are being increasingly used as support tools to ICZM, as their capabilities to simulate the complex processes underlying e.g. coastal erosion increase. In the present paper, examples of the application of numerical coastal models as support tools for integrated management are presented and discussed. Finally, in order to highlight possible benefits from their application to the management of the coast, the numerical models are applied to a stretch of Southern California's coastline, an area subject to severe erosion.

Building codes, floodplain regulations and other construction standards use hazard return periods and annual probability of exceedance estimates to establish acceptable levels of risk to our built environment. If the annual risk is known, the total risk over a longer building design life or management decision lifetime can be calculated with a simple non-linear equation. This paper will address the differences in the way long-term erosion risk to a building must be calculated. Methods to directly compare shoreline erosion risk with other common building standards are described. Shoreline setbacks based on a 70-year erosion rate multiplier are recommended as the best goal to balance the erosion risk with flood, wind and snow hazards to buildings.

The State of Hawaii has organized a multi-disciplinary committee which is in the process of developing a lava flow mitigation plan to address the natural hazard of lava flows on the islands of Hawaii and Maui. Land use and hazard mitigation must be considered in concert to develop communities that are resistant to the impacts of volcanic eruptions and other natural hazards.

Hurricane Lenny (November 1999) exposed significant weaknesses in the coastal infrastructure of islands in the Eastern Caribbean. With financial support from the U.S Agency for International Development, the Organization of American States and the University of the West Indies organized and implemented a five-course training program for coastal zone managers and engineers. This paper presents the structure and results of the training program, and also the elements of a medium term capacity building program presently under development.

Pre-planning for disaster recovery is a critical element of any community's emergency management program. Unfortunately, comprehensive recovery planning is the place where the "Preparedness — Response — Recovery — Mitigation" circle is most often broken. This is not the fault of the emergency management community. Those knowledgeable professionals recognize that all four elements of the circle demand a full measure of attention and resource commitment. In practice, however, the resources available for those activities — staff and dollars — are rarely adequate to allow emergency managers to address all of the needs in each phase of the disaster recovery process.

While many efforts at disaster mitigation have been undertaken, little progress has been achieved in making it part of the everyday decision-making culture. The core of the problem with increasing disaster costs is that the consequences of not building better and wiser are not directly paid by the homeowner or builder and therefore do not influence his decision. This paper will look at ways to expand the utilization of loss reduction measures. It will focus on how public education and information programs, changes in federal and state subsidies, and marketing the benefits of mitigation can build incentives for mitigation activities.

This study employs a wave model called the SWAN (Simulating Waves Nearshore) as an estimating system for waves which cause coastal disasters. The SWAN is applied to reproduction of typhoon-generated wind waves in the Hiroshima Bay and the Osaka Bay, and the validity is examined through comparison between observations and predictions. The comparison showed that the SWAN gives reasonable results as a whole.

The New Orleans District of the Corps of Engineers requires measurements of extreme wave conditions incident to the south shore of Lake Pontchartrain. The data is required to validate the method of selecting wave parameters that are used as input to wave runup models. Wave runup is a critical design parameter for the lakefront hurricane protection structures, principally levees and floodwalls, which protect the city of New Orleans from inundation. The challenge is developing a cost-effective measurement system that maintains a constant state of readiness between hurricane strikes on the Lake (perhaps decades), becomes operational within hours, and performs flawlessly under violent environmental conditions. Functional requirements of the system, including hardware, operations plan, and data products are examined. Permanently mounted and event-deployed gages are considered. The optimal system was selected and will be evaluated through a test deployment.

The paper reports on the experience gained by the Authors during the compilation of risk assessment studies of coastal areas for Italian Local and Watershed Authorities, as well as on the related research activities. The main task carried out in connection with such work was the drawing up of hazard maps for different time horizons (e.g. 3 and 10 years) and different damage levels; the problem associated with both coastal erosion forecasting (which affects long term risks) and wave run-up (which determines short term risks and hazard levels) are quickly reviewed with a strong emphasis on the operational application. New results are provided on the evaluation of storm run up risk on low coasts in connection with significant wave height return time and the potential coastal hazard. While no discussion is provided about the relative efficiency of long-shore erosion models — about which a wealth of literature already exists —some information is provided about the use of laser altimetry and conventional mapping techniques in providing data on the coastline position.

Wind and wave satellite data are now an important tool towards the analysis of sea climate, and their importance is ever increasing as more and more earth observation satellites are launched; since the accuracy of the calibration procedures is of paramount importance, a great amount of work was carried out in the 70s and the 80s to develop reliable algorithms. Thanks to the more recent research progresses in the understanding of the sea spectral characteristics, and to the greater availability of wave buoy measurements, there is ample scope to improve the quality of data retrieval, and specially so of the wind data. Numerical simulation of the altimeter response, performed by the Authors through a spectral model of the sea surface coupled with a parametric conceptual model of the Bragg scattering effect, may lead to some important advances. Numerical results — which will be shown in the paper, highlight a certain dependence of the radar altimeter response signal energy (which is usually taken as an index of the backscattering coefficient and therefore of the wind intensity) from the sea peak period; such a dependence may result in a bias which affects mainly the measurements taken in enclosed or semi-enclosed seas. The objective of the research is to evaluate if the effect of sea state over the signal intensity as shown by the numerical tests is confirmed by the analysis of measured data.

Based on the equivalent triangular storm (ETS) model, Boccotti obtained the analytical solutions for the return period of a sea storm in which the maximum significant wave height exceeds a fixed threshold, and for the mean persistence of the significant wave height above a fixed threshold. In this paper these analytical solutions have been particularized assuming the three parameters Weibull distribution for the significant wave height and the exponential regression base-height of the ETS; the latter distributions have been estimated by using the data of some NOAA buoys moored off the Californian coast. In particular the directional distribution of the significant wave height has been obtained in order to predict the intensity of severest sea storms for fixed wave directions. Finally, the prediction based on the ETS model has been compared to the prediction obtained by applying the total sample method.

Human settlements along coasts and estuaries are increasingly at risk from flooding due to a combination of inappropriate development, rising sea level, insufficient investment in the maintenance of flood defences, and the interaction of rising sea levels with storm surges. This paper describes the development of a dynamical storm surge and inundation model in combination with an analysis of residence vulnerability for two case study sites along the English east coast to investigate the consequences for residential areas of a major sea defence failure. The model is developed to provide detailed information about floodwater depths and velocities that can be expected for different storm conditions and defence failure scenarios. At the same time, failure in residences due to floodwater loading is examined by investigating load characteristics along with damage and failure load parameters for a range of residences. Drawing on historical accounts, field surveys and insurance loss data, those features of residential buildings which govern the structure's vulnerability to flood damage are identified. The examination of the impact of floodwater forces represents a new approach to damage assessment and enables a more accurate prediction of potential losses, both for the case study sites and for larger spatial scales. With this knowledge, sustainable risk management strategies are developed.

In cost/benefit analysis of shore protection works against storm surges in Japan, the effects of prevention from flood are computed as benefits. In this computation, flooding without the works is assumed and the reduced values of properties in the flooded area are obtained taking the loss ratios into account. The loss ratios used in Japan are based on the results of river disaster studies because little data on the damages from storm surges is available. The storm surge due to Typhoon No. 9918 that struck Japan in September, 1999 caused a storm surge in the Yatsushiro and Suo seas, and damage from flooding over wide coastal areas. The loss ratios for general properties due to storm surges from Typhoon No. 9918 were measured in Shiranui Town and Ube City.

Storm damage in the coastal zone results from the forces of wind, waves, and rising water. Rising water, in turn, is a combination of storm surge, tides, and rainfall. These forces and their secondary effects interact in complex non-linear ways that must be analyzed and presented to groups ranging from engineers and disaster planners to the general public. Due to the infrequent nature of extreme events at any given point, simulation techniques are normally required to anticipate storm hazards. This increases the complexity of both the analysis and presentation of the results. This paper describes an integrated approach to analysis of hazards from coastal storms, focusing on tropical cyclone hazards. Simulation techniques are discussed, ranging from operational (real time) hazard assessment through long-term planning and design involving return periods. The incorporation of uncertainty is discussed, as are techniques for the presentation of hazard study outputs. Examples are noted from the Caribbean Disaster Mitigation Project, the Florida Local Mitigation Strategy Mapping Project, and commercial applications. Distribution of hazard data, including the use of interactive web based systems, is discussed.

HAZUS is a major initiative by FEMA for estimating natural hazards losses to population, buildings, infrastructure, agricultural areas and vehicles. For use by local officials and the private sector, the Flood portion of HAZUS (both riverine and coastal) is being given the highest priority, with the Flood Information Tool (FIT) to be released in early 2002, followed by the release of the full flood loss estimation model about a year later. The methodology uses national datasets to characterize flooding and estimate losses and has the capability to accept site-specific local data for more refined analyses. The coastal flooding methodology employs two alternative methods, including a simplified WHAFIS/RUNUP analysis, that have been developed to be consistent with standard methodologies while facilitating their use by a broad group of users.

Vietnam is situated in the tropical monsoon area and the coastal areas repeatedly hit by devastating storms and typhoons. Protective sea dikes are overtopped or breached frequently with the resulting flooding causing loss of life and damage to agriculture land and infrastructure. In the coastal area of the five northern provinces of the Red River Delta 361 kilometres dikes upgrading have been recently realized. A large master plan for measures in Central Vietnam is under preparation. This paper provides a review of actual situation in Vietnam. Some examples of retreat strategy as followed at some coastal stretches are given and also some problems with executing the protective programs are discussed.. Special attention will be given to the necessary upgrading of the design methodology, the developing of appropriate execution techniques and capacity building, and the resulting actions concerning the management aspects of the coastal defences.

Modeling of the propagation of tidal storm surges through a network of tidal channels is crucial for assessing flood risks for properties in coastal floodplains. Quasi-two-dimensional (quasi-2D) modeling capabilities are necessary to model accurately the interaction of channel and floodplain flows during the tidal cycle, as well as flooding and drying of the floodplains. Both MIKE 11 and HEC-UNET models offer these capabilities, and both can simulate channel and floodplain flows under storm surge conditions. Applications of the MIKE 11 and HEC-UNET models to a network of channels during tidal storm surges are described. To provide flood control to these floodplains, the channel system has been equipped with a levee system and associated interior drainage facilities. Because not all the levees in this system were built to the certification standards set forth in the National Flood Insurance Program (NFIP) regulations, the risk of levee failure for a typical levee has been assessed, and the consequence of levee failure on the floodplain has been evaluated. This paper presents the MIKE 11 and HEC-UNET model assumptions and capabilities and derives the water-surface elevation (WSEL) in the floodplain that would result from a typical levee-failure scenario.

The Typhoon No.18 in 1999 attacked the west coasts in Japan on September 23 and 24. The coastal areas were heavily damaged by generation of storm surges and high waves. The port and housing facilities located behind sea walls were destroyed mainly by overtopped waves. The paper describes the procedure to determine the new design heights of coastal barriers for the design typhoon with 100-year return period.

Analysis of coastal flooding events in The Netherlands and Germany shows that most dike breaching events were initiated by failure of the inner slopes of dikes. These failures occurred due to wave overtopping which resulted in slip failure of the inner slope or erosion at the inner slope and crest, or, most likely, a combination of both. In particular, saturation of the dike lowers the resistance to slip failure. Therefore, it is believed that this resistance is strongly affected by wave overtopping. Wave overtopping discharges depend, of course, strongly on the wave conditions that occur at the toe of the dike. Most existing prediction formulas for wave overtopping were derived from physical model tests in which the wave energy is distributed over the wave frequencies following a standard shape, i.e., single-peaked wave energy spectra with a constant shape. However, in practice the foreshore often affects these wave energy spectra such that they become double or multi-peaked. To study how this important effect can be accounted for in prediction formulas for mean wave overtopping discharges, studies presented in this paper were carried out. The applied methods, which include numerical and physical modelling, are similar to those used in Van Gent (2001-b), in which this topic is studied for wave run-up. It was found that the effects of wave energy spectra on wave overtopping can be taken into account by using one particular characteristic wave period in the wave overtopping predictions.

Storm surge prediction models for the Venice Lagoon in Italy have been co-developed and operated by Danish Hydraulic Institute (DHI) and Venice Water Authority-Consorzio Venezia Nuova (CVN) for purposes of operation of proposed flood gates located at the lagoon inlets. Empirically based statistical forecast models have been in operation for many years, and in the last 5 years a deterministic 2-dimensional numerical model based on DHI's MIKE 21 Hydrodynamic model has been added to the suite and is operating in parallel with the statistical models. During these years of operation, a large database of measurements, meteorological forecasts, and flood model results has been compiled. Long term operational flood forecast systems, linked with databases of past model performance and historical environmental information can provide an invaluable tool for the evaluation of past performance, for simulating new assimilation techniques, and for efficient re-analysis. The database re-analysis can ultimately be used to provide updated information on short-term corrections and to provide statistics on uncertainty. In the present paper the status of the models and database will be demonstrated.

Hampton Roads Sanitation District (HRSD), Virginia Beach, Virginia developed an underwater inspection program for nine wastewater treatment plant outfalls. These outfalls are used to convey treated effluent using large diameter pipelines to adjacent rivers, the Chesapeake Bay and the Atlantic Ocean. A baseline underwater inspection of the nine outfalls was conducted in 2000 by a team of engineer divers. From inspection findings, guidelines on inspection intervals and repair recommendations were developed.. Of the nine outfall facilities, four were found to have significant deficiencies. Three outfalls, the Boat Harbor Outfall, the James River Outfall and the Williamsburg Outfall, required immediate repairs. The Boat Harbor Outfall had serious damage to the main barrel and the James River and Williamsburg Outfalls were observed to have blocked diffuser ports. Repairs of the Boat Harbor Outfall, James River Outfall and Williamsburg Outfall are to be completed in 2001. The fourth outfall found to have deficiencies was the Atlantic Plant Outfall. The multiport diffuser showed significant loss of sediment cover over a 2400-foot section two miles offshore in the Atlantic Ocean. The consequences of the loss of cover on the structural stability and durability of the Atlantic Plant Outfall was unknown. The primary concern was structural stability during heavy weather events. A study analyzed the overturning/rotational sliding of the multiport diffuser under heavy weather. This paper provides a synopsis of the program management approach to managing outfalls and an overview of the design considerations used in the analyses of the Atlantic Plant Multiport Diffuser. It also includes a checklist for the inspection of outfalls.

A series of coastal flood insurance studies are being conducted in Whatcom County, Washington to identify existing coastal flood hazards. The coastal flood study of Sandy Point was given the highest priority because of pending development interests and flood risk. This paper describes the methods and findings from this study. The coastal flood study consists of a series of phases. The scoping phase involves efforts to obtain and review data, perform a site reconnaissance and refine the methodology for the project. The tidal hydrology phase includes statistical evaluations of tidal and wind data to establish return period stillwater elevations and wind speeds. The coastal hydraulics phase includes an estimation of deepwater wave parameters, an analysis of wave refraction and shoaling, and a nearshore breaking wave height analysis. Field surveys were conducted to define beach and inland elevations for the estimation of wave runup and overtopping conditions during the 100-year flood event. The hazard mapping phase has resulted in preliminary flood hazard maps for the Sandy Point study area. Coincidently, during the study an estimated 20-year coastal flood event occurred at Sandy Point. The flood event provided a unique opportunity to verify flood study methods and has led to the modification of some standard FEMA coastal procedures for Pacific Northwest coastal flooding.

The Post-Storm Flood Hazard Verification process is used by the Federal Emergency Management Agency (FEMA) to perform validation assessments of the accuracy of flood risk data and information in the published Flood Insurance Study (FIS) and depicted on the Flood Insurance Rate Maps (FIRMs). FEMA believes that mitigation of future flood losses can be achieved by publication of improved flood risk data, if the existing data are deemed to be inaccurate. For the St. Croix study in the U.S. Virgin Islands, FEMA will work with Dewberry & Davis LLC and island officials to assemble and review all studies and data dealing with the storm surge and wave effects resulting from Hurricane Lenny in 1999. This includes the review of the coastal FIRMs and FIS for the entire island of St. Croix. The project requires the comparison of the storm's damaging effects with the flood hazard designation on the FIRMs. Full consideration was given to the probabilistic nature of the FEMA modeling and the actual flood event caused by Hurricane Lenny.

The new Coastal Construction Manual published by FEMA incorporates many `best practices' that are being constructed along the nation's coasts. The manual uses the International Building Code 2000 and the engineering standard ASCE 7-98 Minimum Design Loads for buildings and Other Structures by the American Society of Civil Engineers. These `state of the art' practices and standards come together in a 3-volume set that includes much new information on hazard identification, building siting issues, erosion, and flood loads. The manual builds from what has been learned from historical events to how to use this learning in new designs. A sample home is used as an example of actually designing a home with natural hazard loads from flooding, high winds and an earthquake applied to the building.

Development along coastal areas over the last several decades has placed a number of homes in environments with wind driven rain, high winds, storm surge, flooding, and erosion. Many of these homes have been built to inland standards and are unlikely to survive coastal conditions and storms. Newer homes may be built to wind-resistant standards, but most will benefit from additional details that improve performance. FEMA and HUD have sponsored the development of a Home Builder's Coastal Construction Guide (HBCCG) for release in 2002. Selected topics from the HBCCG that are frequent problems are presented. Poor control of water and moisture intrusion leads to mold, mildew, or even structural damages. Secondary barriers for moisture control and water intrusion are discussed, including common misunderstandings and recommended usage and installation. Positive connections provide a continuous load path throughout the structure to resist lateral and uplift loads. Typical practices for sheathing and framing connections are compared to recommended approaches. Frequently, hurricanes cause extensive damages to homes by failing weaker cladding elements. Common initial failure points of the building envelope will be discussed and possible alternative presented. Careful home siting and foundation construction minimizes exposure to damages, particularly storm surge and erosion. Considerations for home siting and recommended foundations for A and V flood zones are discussed, with particular emphasis on pile foundations.

In November 1996, Typhoon Dale passed to the south of Guam and generated unusually large waves that caused wave uprush and spray onto and above the Orote Point sea cliffs on the west coast of Guam. The large volume of overtopping water overwhelmed the drainage swale behind new bay view homes, entered these homes through the lanai door, and caused extensive flood damage. In addition to the water overtopping the cliff, the forceful waves and spray carried rock fragments of up to fifty pounds beyond the nearly 100 feet cliffs and into the Naval Station (NAVSTA) family housing area. Evacuation was required. This study was to determine the frequency of occurrence for an event like Typhoon Dale and to estimate the nearshore wave characteristics to assist in the development of remedial actions to mitigate the impacts of future similar occurrences. Historical wave events were reviewed to identify extreme events with the potential to generate high wave conditions along the southwest side of Guam. A wave transformation study was conducted to determine wave conditions fronting the cliff of the project site. Numerical models and empirical equations were developed to compute wave runup, spray elevation, overtopping rate, and spray inland excursion distance associated with events of various return periods. Joint probability of occurrence of waves and winds was also studied, and considered in the calculation of spray inland excursions.

This paper looks at the roles played by State and Federal agencies in the management of coastal flood hazards in Delaware. Property protection and the preservation of recreational beach quality are the State's dual management objectives for the developed public parts of Delaware's coastline. With different agency philosophies, programmatic objectives, and priorities, the USACE, FEMA and State of Delaware each are inclined to take different approaches to a problem which might be more efficiently and effectively solved by a unified approach.

Lifeline earthquake engineering is now well established as a component of the earthquake engineering and it used to plan for future impacts in the United States and other countries, such as New Zealand. Applied more broadly, many of these principles apply to civil infrastructure systems management. A joint US-NZ Workshop on Civil Infrastructure Systems Management in Multihazard environments was recently held to discuss this concept, with coastal engineering one of the represented components. Themes that emerged from the Workshop included the need to take a systems-level view of multiple hazards, the interdependencies among infrastructure systems, and the potential for integration of mitigation strategies to achieve multiple (and consistent) objectives. This paper deals with these concepts as they potentially apply to coastal hazards.

One of the City of Chicago's greatest assets is the nearly 30 miles of Lake Michigan shoreline, the majority of which is publicly-owned and maintained by the Chicago Park District. During the summer of 1997, while a 10-year reconstruction program for the shoreline was still on the drawing boards, high water levels coupled with the approaching winter storm season presented a significant threat of damage to lakefront infrastructure, which includes the heavily traveled Lake Shore Drive (US Highway 41), and two of the world's largest water filtration plants. During this period of near-record high Lake Michigan water levels, the City of Chicago's Department of Environment developed and implemented a Flood and Storm Emergency Response Plan. Key components of the Plan included identification and prioritization of at-risk facilities, design of mitigation measures, preparedness, procurement of additional flood-fighting equipment, and designation of available resources for response and recovery. Instrumental to the success of the Plan was the forging of a public/private partnership and interagency cooperation between Local and Federal officials. The development of a tiered response system allows for the City to utilize internal personnel to the extent that they are available, without compromising their ability to respond to other emergencies, and to draw on private sector resources in the event that municipal resources are insufficient. Since 1997 the plan has been activated several times, with the result that disruption and damage to Lake Shore Drive and other City infrastructure has been reduced.

In the aftermath of Hurricane George, Louisiana emergency management and transportation officials realized that the State was probably not as well prepared for such an event as they may have originally assumed. One of the key areas of concern was the lack of access to timely and accurate information regarding the status of evacuation routes. Emergency management officials were in effect "working blind;" with little knowledge of which evacuation routes were flowing smoothly and which were in gridlock. As a result, they were unable to redirect traffic from routes that were over capacity to parallel routes, only miles away, that were carrying little traffic. In response to this problem the Louisiana Department of Transportation and Development (DOTD) and Louisiana State University (LSU) initiated a research effort to develop innovative and cost effective ways to get access to timely traffic flow information. What has evolved is a partnership between the DOTD, LSU, the United State Geological Survey (USGS) and the private sector that is working toward the creation of a state-wide traffic, weather, flood, and bridge scour monitoring system for critical routes within the State. This paper summarizes the concept plan for the system and highlights many of the features and capabilities that have been incorporated into the pilot system. It also presents some of the unique aspects of the system and the unique partnership that has been formed between the DOTD and USGS to make this system a reality.

From 1960 to 1990, Florida's population nearly tripled, increasing from 4.951 million to 12.938 million people. The intense urban settlement activities resulted into a string of settlement centers along the coastal areas especially in the southeast and central west coasts. High numbers of permit filings in recent years in various Florida counties indicate that population density will continue to increase especially in the southeast coastal regions. Projections of the population per mile of coastline suggest that, by the year 2010, the population density on Florida's east and west coasts will increase about 130 percent from 1990 levels. Risk is defined as the product of probability of an event and its consequences. Land use characteristics and land development activities are the major factors that contribute to vulnerability in high-risk coastal areas to hurricanes. This paper addresses the consequence component of the risk equation in terms of population increase and land use in view of the infrastructure demands for hurricane preparedness. Changing demands on infrastructure and emergency management are addressed in view of the changing needs of the communities.

The organization and structure of two narrow cold frontal rainbands (NCFR) observed by instrumented aircraft during the PACJET-2000 field experiment are presented. Doppler radar observations are shown which reveal the severe nature of the events. Strong surface winds, pea-size hail, and heavy rainfall accompanied the passage of the rainbands over the coastal regions of Northern and Central California. There were many similarities in NCFR structure to that observed in mid-latitude "Supercell" thunderstorms including echo overhang, echo-free faults near the leading edge, and possible waterspouts. The NCFR's differed in vertical structure from the supercells in that they were about one-half as tall. The relatively short vertical extent limits the detection of these storms by coastal National Weather Service Doppler radars because of beam overshooting During the PACJET research program an attempt was made to aid the forecasting of hazardous weather phenomena through the use of instrumented aircraft observations provided (via a satellite data link) to National Weather Service forecasters. Preliminary results indicate the success of this effort, as the forecasters were able to use the data in preparation of warnings.

This study documents the frequency variation of land-falling tropical cyclones (TCs) in North Carolina (NC) from 1887–1999. While there has been significant variability over the 113 year period, a visual inspection of the record suggests a strongly modulated pattern of activity with periods ranging from quiet to intense to somewhere in between. So, questions regarding multiple dominant frequencies in NC TC activity and whether or not the recent increase in the number of TCs affecting NC will continue into the next few decades are addressed in this study. Four principal modes and a residual are found in the NC land-falling TC time series. 1st mode has an inter-annual time scale of 2–7 years correlated with the Biennial Oscillation, the El Nino/Southern Oscillation (ENSO) phenomena and the inter-annual variability of precipitation in the African Western Sahel. 2nd mode has a time scale of 8–12 years correlated with the Atlantic sea surface temperature (SST) dipole pattern. 3rd mode has a time scale of 20–40 year correlated with the North Atlantic Oscillation (NAO). 4th mode has a time scale of 40–60 years positively correlated with the 40–60 year oscillation of both the tropical Pacific SST and the Western Sahel rainfall. The residual trend is bowed from ∼0.9 events per year (e/y) in the late 19^th century to a low of ∼0.8 e/y in the mid 20^th century, rising slowly to about 1.0 e/y presently.

Recent analyses of NCEP reanalysis and in situ data covering the past 50 years reveal major changes in the climatology of the North Pacific winter (December–March) cyclones. During this time the frequency and intensity of extreme cyclones have increased markedly, with associated upward trends in extreme surface winds and a southward shift in the storm track. The increasingly vigorous cyclone activity is apparently related to strengthening upper tropospheric over the central North Pacific that appear to be related to increasing sea surface temperatures in the western tropical Pacific are a plausible cause of the observed changes. To investigate the impacts of these changes on the California wave climate we have conducted a wave hindcast for the North Pacific covering the months of December–March for 1948–49 through 1997–98. Comparisons between the wave model results and measurements from NOAA buoys (available since the late 1970s and early 1980s) show excellent agreement. The results show trends towards larger and longer period extreme waves over nearly all of the mid-latitude North Pacific, with the largest values (up to 2 meters in 50 years) between 25° and 40° N. Along the coast of North America the largest trends are found in Southern California and northern Baja California. In this region, the changes in deep-water wave climatology are such that the estimated 100-year extreme significant waves heights for 1948–75 becomes a 10-year event for 1976–97. For inshore waters, where continental and island sheltering are important, these changes have been by the southward shift in the storm track and consequent tendency towards more westerly approach directions. These effects are site specific but a common result (when the effects of refraction and sheltering are taken into account) is that the estimated 100-year wave during 1947–75 becomes a 1 to 2-year event during 1976–97. Results from a simple model of longshore sediment transport indicate that the changing wave climate may have had important impacts on coastal erosion and sand transport.

Sea level rise due to climate warming will amplify coastal hazards such as storm surges, beach erosion, and loss of wetlands. Sea level in the New York metropolitan region has risen steadily by 22–39 cm during the 20th century. Projections based on both historic trends and climate model simulations (Hadley Centre, UK and Canadian Centre for Climate Modelling and Analysis) suggest that regional sea levels could climb another 18–60 cm by the 2050s and 24–108 cm by the 2080s, over late 20th century levels. The return period of the 100-year storm flood could be reduced, on average, to 19–68 years by the 2050s and 4–60 years by the 2080s, resulting in more frequent damaging coastal floods. Around 38% of the land surface of salt marsh islands has disappeared in Jamaica Bay, New York City between 1974 and 1999, due to the interaction of a number of anthropogenic factors and sea level rise. Given these stresses, the saltmarshes are not likely to survive accelerated sea level rise without urgent remedial action. The modest sea level change projected for the next 20–30 years provides a grace period during which coastal managers, planners, and other stakeholders can develop appropriate mitigation/adaptation strategies and policies to cope with longer-term sea level rise.

The National Severe Storms Laboratory (NSSL), the National Sea Grant (SG) College Program and the North and South Carolina Sea Grant programs have begun a joint project centered in the North and South Carolina areas affected by Hurricane Floyd. This project, called IFLOW (Inland Flooding Observation and Warning), will establish a research and development demonstration program for the evaluation and testing of new technologies and techniques to produce accurate and timely identification of coastal and inland floods, and flash floods.

The North Carolina State University Coastal and Estuary Model & Environmental Prediction System (CEMEPS) is a coupled system of mathematical models. CEMEPS contains a suite of interactively linked atmospheric, oceanic, estuary and river model components. The model architecture couples mesoscale atmospheric models or event models such as hurricanes or a suite of atmospheric variable parameterizations to ocean basin, continental margin, and estuary hydrodynamic models to a river interaction model. So, winds and precipitation are both observed and modeled and water waves and currents and water levels are predicted. Thus, full storm surge and event-related estuary to inland flooding can be accurately determined well in advance of a storm. CEMEPS output is routinely used by the North Carolina Office of the National Weather Service to make forecasts of coastal and estuary flooding during the passage of Tropical and Extra-Tropical Cyclones. While the model system is currently focused on the coasts of the Carolinas, CEMEPS could be ported to all coasts, including the U.S. Atlantic seaboard, the Gulf coast, the Pacific coast and the Great Lakes. The goal of CEMEPS is to improve the capacity of coastal communities to reduce flood impacts.

This paper provides an overview of activities underway in NOAA's National Centers for Coastal Ocean Science-Biogeography Program that are applicable to determining the impacts of climate change on the biogeography of living marine resources. The paper demonstrates the utility of a biogeographic process in modeling and assessing the potential impacts in marine ecosystems. The process is organized around three components: 1) Data Inputs, 2) Science Products, and 3) Management Tools. Two case studies are presented that utilize the biogeographic approach to demonstrate the utility of the process in understanding potential ecological impacts due to climate change and variability. First, a study is presented on determining the impacts of changes in freshwater inflow on the eastern oyster in Apalachicola Bay, FL. Results indicate that under drought conditions and high human demand for freshwater, hydrodynamic characteristics of the bay would be conducive to increased oyster mortality due to predation and disease. Case study two demonstrates how the biogeographic process increases climate change assessment capabilities by coupling species distributions and abundance to benthic habitats found within coral reef ecosystems. A modeling approach is provided to conduct impact assessment scenarios based on ecosystem responses to climate change.

If climate changes predicted for the next one hundred years do in fact occur, coastal management plans and physical structures being designed today may face conditions during their design lifetimes that are significantly different from historical climate. This presents a serious challenge to engineers, coastal planners, and emergency managers who have depended on history to be a guide to the future. Climate change may lead directly to changes in the frequency and intensity of storms, or it could lead to environmental changes which would alter the impact of given storm events. Here these problem areas are discussed, along with simulation approaches to assist decision-makers evaluate the potential for altered risk due to climate change. Examples for wind return periods and storm surge modeling are discussed.

The present paper describes a cyclone wind model and storm surge and flooding model for the east coast of India. They form part of the operational Storm Surge and Flood Forecast System that was recently developed and implemented in India. Results from these models are used to produce flood maps and potential wind damage maps with the help of GIS layers. The cyclone wind model is based upon that of Holland, and was modified for the present applications. A high-resolution time interpolation scheme has been devised, which uses a moving grid. The concepts and the application have been validated using a number of actual cases including the super cyclone ORISSA. A stable and efficient overland flooding procedure is presented. It is shown that the surge and flooding model is able to reproduce the inundation with high degree of accuracy. The set-up of the 24 hours operational system that includes the receipt of up to date observational data through satellites is also presented.

The meteorological community has moved to ever higher resolution numerical weather predictions as a consequence of our increased computer capabilities. However, our ability to observe and accurately predict weather events down to scales that result in localized heavy precipitation and extreme winds is challenging at best, especially along the California coast with its complex topography. Significant progress is being made in developing a coastal mesoscale observing network to aid in monitoring small-scale weather patterns. These observations are used to quantify numerical model prediction error on small scales and results show definite limits to our predictive capability for localized weather patterns. These results show that the main source of error is often the larger scales and that the small scales are sometimes highly sensitive to small errors, which limits their predictability.

The Research and Technology Centre Westcoast (FTZ) is carrying out a micro-scale risk evaluation study for selected coastal lowlands along the German North Sea and Baltic Sea coasts. This work is within a framework of a reorientation in the German coastal defence policies of Schleswig-Holstein. The methodology developed here is cost-effective and can be applied to other coastal zones. A generic concept of Risk Handling & Natural hazards developed in the early phase ensures generality to different administrative and political levels. The method includes the three interlinked segments of risk analysis, risk evaluation and risk management. A hazard determination is carried out for the different study areas on the coasts of the North and Baltic Sea on the basis of the given hydrological and morphological conditions. The specific flooding- and dike breach probability is computed. In parallel, the damage potential is assessed through a vulnerability analysis. The expected damages can then be evaluated through an examination of different scenarios. The specific risk can be calculated for the different study areas on the basis of a combination of occurence probability and damages. Out of these results strategies and measures for preparedness and mitigation shall be diverted in the frame of the subsequent risk management. The methodology is useful for both disaster planning and recovery.

Climate change is posing great risks on Germany's densely populated coastal zones. Sea-level rise is accelerating and likely to amount to 6 mm/y by 2100 which is about 4 times the previous rate on the North Sea and Baltic Sea coasts. As a result recurrence of extreme storm flood levels will increase significantly, as will erosion rates along sandy shorelines. Consequently, parts of the low-lying areas and as many as 3 Mio. people living there are at risk from flooding. Existing protective structures; e.g. North Sea dikes, will have to be improved but this proves particularly difficult within major seaport cities such as Hamburg. Along the Baltic Sea large cities and tourism resorts are still without adequate flood protection. There, high investments in flood and erosion defense strategies will be necessary in the upcoming decades.

The intertidal beach profile of a low-energy microtidal beach was monitored at regular intervals for a period of six months over the winter season 2000–2001. In addition to that, selected surveys were undertaken following medium energy (H_s<1.5 m) events known to generate beach changes in the area (E-SE winds). The response of the beach to these events was modeled using the convolution method, simulating the response of the profiles as surveyed immediately before the event. The model generally does not represent correctly the observed evolution of the beach above Mean Sea Level (MSL), possibly because the effect of storm surges was not included. On the other hand, the performance of the model is better for the submerged beach. A simulation of the impact of the 1-year wave event was undertaken, using the surveyed profile that seemed the most stable. The underwater changes underline a flattening of the lower shoreface, but the intertidal bar maintains its shape and erosion of the dune face is limited. This underlined the important role of the dune-trough-bar system in protecting the back-barrier environment, although its behavior under a consistent storm surge remains to be studied. Finally, a longer term (10 years) evaluation of profile response was undertaken using the Bruun's Rule, considering a worst-case scenario of Relative Sea Level Rise of 13.4 mm/year, which is locally controlled by subsidence. A shoreline retreat of 7.4 m is forecasted for the next 10 years. Once again, the largest impact is predicted for the system where the dune-bar system is not fully developed.

With human welfare, high investments, and significant environmental resources and amenities at stake, a rise in sea level and potential changes in storm climatology as a result of anthropogenic climate change are of utmost relevance to coastal zone policymaking, development, and management. Yet until very recently, concern with global climatic and related environmental changes among US coastal managers, especially at sub-national levels, was and continues to be rather scant. Arguments in the late 1990s claimed that this lack of concern and response to these synergistic environmental threats was in large part due to the lack of immediacy and "good, useful information." The research reported here provides a more detailed account from a comparative case study of several US states, and suggests ways in which to improve the relevance, credibility, and legitimacy of global change information in US coastal zone management.

The U.S. Army Corps of Engineers (Corps) was involved with billions of dollars worth of hurricane and storm damage prevention, ecosystem restoration and other coastal engineering projects in 2001. Current public policy demands that the Corps evaluate the economic benefits and costs of its projects over a projected fifty-year life span. With the current trend in global warming and the resulting rise in eustatic sea level, public awareness of the importance of sea level change considerations has increased dramatically. Corps policy on how to assess and apply sea level change to coastal engineering projects is critical to proper economic analysis of projects as well as to project success. Recognizing that relative sea level change is potentially more important to coastal engineering projects than eustatic sea level change, the Corps bases its policy on an assessment of the risk of accelerated sea level rise as compared to observed historic trends. It applies these considerations to "every coastal and estuarine (as far inland as the new head of tide) feasibility study that the Corps undertakes." In accordance with suggestions in the National Research Council's 1987 report on sea level change, Corps feasibility studies consider which design alternatives are most appropriate for a range of possible future rates of rise. The feasibility studies then use risk/sensitivity analysis to quantify the benefits and costs of design alternatives. These design alternatives should include those based on the observed historic trend in sea level change and those based on various possible accelerated rates of change.

Bogue Banks, North Carolina, is a 25-mile (40 kilometer) long barrier island in the lee of Cape Lookout, midway between Cape Hatteras and Wilmington, North Carolina. It is oriented east-west and is sheltered from northeast storms by the cape. However, it is directly exposed to hurricanes and has sustained five land-fall tropical storms since 1996, the most recent of which was Floyd in September 1999. Historical shoreline recession rates have been low, with most estimates averaging about 2 feet per year (ft/yr) [∼0.6 meters per year (m/yr)]. In contrast to many barrier islands, Bogue Banks has relatively high relief, reaching elevations greater than 50 ft (15 m). Typical foredune elevations are 16–33 ft (5–10 m) above sea level, and washovers are nonexistent. With an increased frequency of storms, Bogue Banks' erosion has accelerated and has led to extensive damage to the dune system, walkover structures, ocean piers, and many buildings. Damages from Hurricane Floyd along the oceanfront were estimated to range from $5 to $10 million. The present study determined that Floyd caused dune recession averaging 15 ft (4.6 m), accretion of the mean high water contour averaging 25 ft (7.6 m), and a maximum volumetric erosion for any reach of about 18 cubic yards per foot (cy/ft) [45 cubic meters per meter (m³/m)]. Beach scraping combined with natural recovery after the storm restored the beach to prestorm conditions such that nine months later, there was negligible net loss in beach volume measured to approximate closure depth. The primary mitigation measures after each hurricane have been beach/dune scraping, reconstruction of walkovers, and emergency sandbagging. Only a few houses have been relocated. The recent erosion experience at Bogue Banks has sparked debate regarding what course of action to take-whether to abandon property, relocate, or rebuild the beach.

High-resolution topographic data are essential to mapping and mitigating coastal flooding and erosion hazards. The recent advent of airborne laser altimetry technology allows rapid and inexpensive topographic surveys of large coastal areas.

With billions of dollars worth of property and infrastructure threatened by coastal erosion, there is a pressing societal need to identify and mitigate this hazard. Following a congressional mandate, the Federal Emergency Management Agency conducted a pilot study to examine historical shoreline change and to determine the cost effectiveness of mapping erosion hazards under the National Flood Insurance Program. The mapping phase of the study confirmed that long-term erosion is a widespread problem, but also revealed that further research to examine mapping techniques and methods of data analysis is necessary to improve our ability to accurately predict future shoreline change. In sediment-starved coastal regions (e.g., the mid-Atlantic seaboard), the local geologic framework can provide a critical but often ignored context for the interpretation of long-term erosion rates. A general geostatistical technique for quantifying the influence of nearshore geology in controlling long-term erosion is being developed using the northern Delmarva Peninsula as a case study. Some of the lowest erosion rates are found in areas where relict Pleistocene and older shorelines intersect the modern barrier-island system, providing resistance to shoreface erosion and, in some instances, a steady supply of beach-compatible material. In addition to the geostatistical analyses, a novel approach for determining the error associated with several methods of calculating erosion rates was tested in Delaware and New York. In these case studies, the best erosion forecasts were those derived from linear-regression rates calculated using 19th and 20th century shoreline positions, excluding shorelines surveyed after major storms.

The Oregon Coast can be divided into compartments by large headlands forming littoral cells that restrict the flow of sediments. Most of these sediments have reached a state of equilibrium controlled largely by the relative sea level rise and disrupted only by episodic storm events, man made changes to the sediment supply, and climatic shifts such as El Niño and La Niña. Shoreline change occurs on spatial scales of centimeters to kilometers and operates on time scales ranging from seconds to decades. As a result of new high-resolution LIDAR technologies, we are able to identify and quantify these large-scale changes and examine some of the smaller scale changes. Erosion on the Oregon coast caused by the 1997–98 El Niño event produced an observable pattern of shoreline change. In October of 1997 and then again in April of 1998, LIDAR was flown over the Oregon Coast, bracketing the El Niño and enabling us to quantify the erosion at a variety of scales. The objective of this paper is to show how different applications of LIDAR are used to perform shoreline change analyses in Oregon; the Netarts Littoral Cell in the north and the Bandon Littoral Cell in the south. The results of these shoreline change analyses have implications for coastal management issues and have facilitated regional hazard planning.

The main objectives of this study are to develop a property based risk assessment method to serve as a model for oceanfront structures on the North Carolina coast and to offer a GIS-based methodology for identifying and analyzing shoreline vulnerability indicators for individual oceanfront structures. The area and storm event considered in this research is Topsail Island, NC, as impacted by Hurricane Fran in 1996. Pre- and post-storm conditions were obtained from digital elevation models (DEMs), orthophotography, and structural survey data taken before and/or after the storm. Shoreline and structural characteristics of structures known to have failed and survived the storm were compared to reveal vulnerability indicators and develop the proposed property based risk assessment method. This study successfully presents a methodology for incorporating GIS procedures and 3-dimensional data to evaluate shoreline vulnerability indicators and develop property based risk assessments. The resulting risk assessment method proved to be a good predictor of structural failure and survival within the study area.

Analysis of coastal processes at Pawleys Island, SC, particularly beach profile change has been enhanced through the use of the US Army Corps of Engineers' Beach Morphology Analysis Package (BMAP). This tool provides rapid, efficient, qualitative and quantitative assessments of historical and predictive beach profile change. BMAP provides several useful applications including linear interpolation to calculate an average profile for a series of profiles with an option to compute and display the standard deviation, minimum envelope, and maximum envelope of profile change. BMAP also has the capability to compute volumetric change, both total and sectional volumes defined by starting and ending boundaries and a vertical datum. Similarly, cut and fill areas between two profiles can be calculated. In addition, BMAP can compute contour recession changes for a particular vertical datum and selected profiles, which is useful in estimating short-term and long-term erosion rates. In this analysis, BMAP is applied to historical data sets of Pawleys Island, South Carolina including beach profile surveys from 1990 to 2001, extending from the dune face to approximately 4000 ft (1.2 km) offshore. Qualitative and quantitative estimates of volume and contour position rates of change are computed for use in the Pawleys Island Storm Damage Reduction Study currently being conducted by the Charleston District Corps of Engineers.

The U.S. Army Corps of Engineers (USACE), Detroit District and key cooperators are conducting the Lake Michigan Potential Damages Study (LMPDS). Three primary objectives of the study are to develop (1) a lake-wide potential damage model for the prediction of flood, erosion, and low water damages; (2) a set of tools for use by coastal managers and other officials; and (3) a sound understanding of the relationship between Great Lakes water levels and coastal geology, processes, and erosion. This study will create a modeling procedure and engineering/management tool for predicting future shoreline retreat and calculating economic damages due to erosion, lake level changes, environmental, ecological, and related social / cultural impacts. This modeling approach also allows the team to investigate hazard mitigation alternatives, such as a revised approach to permitting or increasing setback planning and adherence policies. Once the study is complete, local communities can use the data and GIS tools developed to enhance coastal planning and management decisions, with the goal of reducing economic losses along the open coast.

Probabilistic slope stability analyses were compared to observed failures between the late 1970's and the mid 1990's along Wisconsin's Lake Michigan shoreline bluffs. An emphasis is also made on the importance of understanding the slope failure mechanism and incorporating the failure mechanism in modeling of slope behavior. Profiles along approximately 300 miles of shoreline bluffs were measured, analyzed and evaluated using deterministic methods in the late 1970's. Profiles along approximately 175 miles of shoreline were re-measured in 1995 and 1996. The shoreline bluffs studied are up to 40 meters (130 feet) tall and are composed of glacial and lacustrine sediments. Spring climate conditions and seasonal groundwater changes appear related to rotational failures along this shoreline. Our probabilistic analyses modeled changes in the internal groundwater elevation and variability in strength parameters, rather than external erosion impacts on the bluff. Probabilistic results were viewed using the reliability index, which can be converted into a probability of failure. Analyses were made using the 1975 to 1980 field measurements and then compared to the failures observed between the initial measurements and 1996. This allowed an empirical measure of the prediction accuracy of probabilistic slope stability models in the study area. The comparison of the model results to observed slope failures demonstrated the need to adjust the failure criteria so failing slopes could be more accurately predicted. An empirical calibration value of the probabilistic model was then developed to give the engineer a realistic probability of slope failure.

Along the Big Sur coastline in central California, the rugged Coast Ranges descend abruptly into the Pacific Ocean, creating one of the most extreme coastal slopes in the conterminous United States. Weak rocks and steep topography provide ideal conditions for frequent large landslides, which contribute a substantial portion of material to the overall littoral sediment budget. Little is known about the nearshore sediment budget in this area, including the amount, rate and frequency of input to the system from coastal landslides. Adjacent to the Big Sur coastline is the Monterey Bay National Marine Sanctuary (MBNMS), a protected area of coastal waters and home to a variety of aquatic species. The California Department of Transportation (Caltrans) is exploring solutions to the problems faced with keeping slide-prone coastal Highway 1 open and safe while minimizing impacts to the MBNMS below the road. As a contribution to developing a highway management plan, and in order to advance the fundamental understanding of processes along this stretch of coastline, we have developed a technique to quantify the historic volume of sediment that enters the littoral system from coastal slope failures. A pilot study was conducted as a means to test and refine the technique along the Big Sur coastline. Digital photogrammetry is used to produce Digital Terrain Models (DTMs) from historical and recent aerial photography. The DTMs are then subtracted to quantify amounts and identify areas of volume loss and gain along the coast during the period spanned by the aerial photographs.

Field investigations were undertaken to study the modes of failure of coastal slopes forming part of the shorelines of Wisconsin, southern California, England and Mexico. The slopes in Wisconsin and southern California are made of glacial soils and cemented sands, respectively. The slopes in England are located in Dover and are made of chalk. The Mexican slopes are located in Tulum and are made of limestone. Weathering of the slopes' faces and wave action at the toe of these slopes are the primary factors responsible for changes in their slope geometry. The coastal slopes made of soil evolved as a result of an interaction between weathering and wave action. Three modes of slope evolution were found for these slopes. The modes of slope evolution were related to the intensity of wave action at the toe of the slopes. The coastal slopes made of rock failed as a result of a wave induced notch that developed at the toe of the slopes.

This paper presents an update of the U.S. Army Engineers National Shoreline Erosion Control Development and Demonstration Program ("Section 227"). This research and development program was initiated in January 2000 with the primary objective to evaluate, construct and monitor the performance of innovative shoreline erosion abatement strategies on U.S. coastlines. Demonstration projects represent a wide range of techniques and site conditions, and project results are broadly applicable to other coastal shores. To date, one project is in the construction phase and seven are in various stages of the planning and design. Lessons being learned through the program and from each demonstration site provide insight into appropriate shore protection strategies to either reduce future potential or for responding to existing disasters.

This paper summarizes the approach, method and results of a wave runup analyses conducted for the City of Imperial Beach, California. The objective of the study was to evaluate the performance of existing shoreline protection devices along Imperial Beach in preventing wave overtopping. Typical coastal structure design in Southern California cities was based on limited wave analyses right at the project site. This study relies on extensive numerical wave modeling to provide local regional wave conditions along the entire City of Imperial Beach shoreline. The wave modeling results were then used for wave runup/overtopping analyses along different reaches of the shoreline according to structural types and conditions for each reach. This wave runup/overtopping analysis was part of a comprehensive study to assist the City of Imperial Beach in developing a shoreline protection device ordinance.

The Four Seasons Resort in Nevis, West Indies suffered significant shoreline damage and loss of property due to storm waves from Hurricane Lenny. This paper presents the subsequent engineering efforts to rebuild the beach and design a shoreline protection system for the resort. These efforts included damage assessment, wave hindcasting, numerical modeling, and physical modeling. The resulting system consisted of a segmented, low-crested breakwater, buried revetments, and a renourished beach. To date, the system has performed according to expectations.

The SR-105 Emergency Stabilization Project was constructed in the summer of 1998 to protect a stretch of state highway from destruction because of shore erosion. The project consists of a rock groin and dike structure and beach nourishment. A recently concluded monitoring program has shown that the project has performed to design expectations. The project has the added benefit of reducing beach erosion along an extremely erosive shoreline northwest of the project site. The project, specifically the underwater dike, has induced relocation of a deep tidal channel approximately 500 to 2,000 feet further from the shoreline, resulting in favorable conditions for the recovery of the shoreline. Scour has developed at the toe of the underwater dike that may endanger the stability of part of the structure and the performance of the project. Alternative actions to prevent scour and reduce risk to the structure were developed and are presented below. Also, the project resulted in the development of approximately 16 acres of shallow water habitat. Approximately 15 acres of this habitat are protected from waves and are likely the most environmentally valuable habitat in the area.

The Orote Landfill Site is located in the Apra Harbor Naval Complex on Guam. The landfill was used from 1944 to 1969 for the disposal of residential, commercial and industrial waste. Subsurface investigations as part of the Navy CLEAN program confirmed the presence of contaminated materials. Observations in 1997 determined that the seaward edge of the landfill had been eroding since 1990, with landfill waste found on the beach. Significant concern was raised regarding the potential for the landfill waste to introduce contaminants into the Orote Point Peninsula Ecological Reserve Area in the Philippine Sea. A major project was initiated to (1) prevent future erosion of landfill materials to the beach and marine environment; and (2) prevent human and ecological receptors from coming in contact with the landfill surface soil or waste materials. This paper summarizes the key project design and construction elements. Design challenges included a design wave exceeding 40 feet, the interaction of these massive ocean waves with the cliff shoreline, and remote construction access.

The huge storm surge and waves of Typhoon No. 9918 attacked the southern part of Japan in 1999, killing 12 people and inflicting severe coastal damage. Not since the typhoon of 1959, which killed more than 5,000 people, had such a major disaster occurred in Japan. This is a result of subsequent construction of intensive coastal facilities against storm surges along very long coasts and especially in large bays. Here, we review the historical development and characteristics of Japanese coastal defense facilities, while also describing the recent typhoon damage and discussing problems related to current numerical tools for storm surge prediction in Japan. Finally presented is our version for future coastal design methodology, which is based on the performance design.

A visionary beach management program is discussed in which local government plays an active role in data collection, analysis and monitoring of the entire coastal system. Advantages of the new approach involve the use of innovative partnerships or techniques to solve beach management issues. The proposed approach requires on-staff expertise and has been developed as an alternative to the project-by-project studies that are usually conducted by outside consultants. A major focus of the program is to not only monitor long-term beach changes, but also to quantify short-term beach changes including pre-storm preparedness and post-storm documentation.

The Minerals Management Service Sand and Gravel Program provides for access to sand, gravel, and shell resources on the Outer Continental Shelf through negotiated agreements provided that the resource is used for Federal, state, or local government shore protection, beach restoration, or coastal wetlands restoration projects. In 1994, Congress amended the OCS Lands Act authorizing the program. In 1998, Congress passed legislation waiving all fees for the Federal resources conveyed under the 1994 OCS Lands Act amendments. Beginning in the early 1990's, the Minerals Management Service began working with coastal states along the east and gulf coasts of the United States to identify sources of sand that can be used for coastal erosion purposes. These partnerships were and continue to be active because state geologic scientists are pursuing the need to identify those sources of sand that are compatible for beach nourishment and hurricane protection projects. Companion environmental studies are also being conducted by environmental scientists so that sand resources identified in these sites can be made available to state and local communities in a timely manner. The purpose of this paper is to highlight the activities and the results of the active MMS/State sand cooperatives in Alabama, Louisiana, Texas, Florida, South Carolina, North Carolina, Virginia, Delaware, Maryland, and New Jersey. Results and use of the companion environmental studies that are conducted will also be discussed.

Coastal erosion is one of the most significant problems affecting Maryland's diverse coastal environment. Approximately 31% of Maryland's 7,020-kilometer coastline is experiencing some degree of coastal erosion, resulting in the loss of approximately 1.05 square kilometers of land per year. In January 2000, the Governor's Shore Erosion Task Force recommended development of a Comprehensive Erosion Control Plan for the State of Maryland. The Comprehensive Plan would coordinate erosion control planning and move Maryland away from the project-by-project approach currently used. In order to initiate statewide planning, the Maryland Department of Natural Resources established partnerships with two coastal counties. These partnerships have three concurrent components. First, data will be collected and analyzed for a portion of the county to provide both State and county planners with a clearer understanding of the economic, cultural and environmental costs of both shore erosion and sea level rise on a local basis. Second, erosion control needs and strategies will be examined and prioritized on a countywide basis, which will increase the effectiveness of erosion control activities and aid the county in soliciting federal and state funding. Finally, public outreach will be conducted to increase public understanding and awareness of erosion control issues and solutions. These partnerships will be used as templates for the development of the statewide components of the Maryland Comprehensive Shore Erosion Control Plan, which will assist in planning and prioritizing areas in need of assistance on a statewide basis.

Building setbacks in coastal areas are often established using average annual erosion rates as a predictor of future shoreline trends. Review of actual shoreline movements in many areas reveals what are often wide variations in erosion rates through time. Setbacks based solely on average annual erosion rates fail to take this variability into account, and may understate the true erosion risk to a structure, depending upon its location relative to the setback. This paper presents a method to review erosion rate variability at a site and to better gauge the likelihood that a structure at a given location will be undermined by erosion.

As recently advocated by Healy and Dean, assessment of appropriate development setback based upon identified coastal hazard along open duned coasts may be evaluated from 4 essentially independent factors, viz., historical shoreline change rate, decadal term "cut and fill", a sea level rise effect, and a dune stability factor. The setback delineated is based upon a 100 year planning horizon, and derived from the beach-dune profile. The initial setback determination is then subjected to 3 tests, viz., (i) is there sufficient sand in the beach dune reservoir? (ii) is the setback zone-subject to storm surge flooding? and (iii) is the setback zone subject to tsunami inundation? The calculated setback zone may also function for other purposes including coastal landscape preservation, ecosystem protection, and preservation of cultural sites. Major difficulties arise when applying the scheme to already subdivided coastlines, when community views must be considered in an ICZM context. This methodology of determining one integrated hazard zone is considered superior to implementing sequential zones of supposed reducing hazard.

Methodologies have been developed to establish setback distances for use on the coast of the Pacific Northwest where the principal hazards are wave runup and surge during major storms, and El Niños that produce unusually high tides and the northward movement of beach sand within littoral cells, creating "hot spot" erosion sites. Of concern is the discovery that the severity of storms and their generated waves have been increasing for at least the past 25 to 50 years, with the underlying cause and possible connection to global-climate change not being fully understood. Important are extreme water levels that result from combinations of high predicted astronomical tides, processes related to El Niños that elevate tides still further, and the occurrence of a major storm that produces high levels of wave runup on beaches. Having made such an assessment, a geometric model is employed to evaluate the potentially maximum horizontal retreat of foredunes, thereby serving as a guide for the placement of setbacks in dune areas. In areas where the beach is backed by sea cliffs, the analysis yields a determination of the average number of hours per year the cliff is impacted by the high waters of tides plus wave runup, providing an assessment of the susceptibility of the property to wave attack, one component in the evaluation of an appropriate setback distance.

The Oregon coast is subject to catastrophic hazards including earthquakes, and earthquake-induced landsliding, liquefaction, subsidence, as well as tsunami. A prototype coast-wide GIS has been developed to support decision-making pertaining to these catastrophic hazards. The GIS consists of a series of countywide `templated' physical and cultural map/attribute layers. Examples of specific map/attribute layers include tsunami inundation lines, tsunami evacuation lines, schools, hospitals, and police and fire stations. The focus of the prototype GIS was to facilitate tsunami evacuation route planning in coastal communities. To this end, maps made from the GIS and reviewed by stakeholders were used to develop evacuation brochures for several coastal communities. The benefit of using a GIS to support such efforts is that relevant information is easily accessed, readily updated, and consistently displayed on a coast-wide basis. It is anticipated that the prototype will form the basis for a larger GIS that can be used to support planning for all catastrophic hazards.

In many places in the world the written record of tsunamis is too short to accurately assess the risk of tsunamis. Sedimentary deposits left by tsunamis can be used to extend the record of tsunamis to improve risk assessment. The two primary factors in tsunami risk, tsunami frequency and magnitude, can be addressed through field and modeling studies of tsunami deposits. Recent advances in identification of tsunami deposits and in tsunami sedimentation modeling increase the utility of using tsunami deposits to improve assessment of tsunami risk.

There is little question that offshore seismic sources exist and could trigger tsunamis directly or through coseismic submarine offshore landslide or slump generation. While some earlier 19th century reports are subject to interpretation, more than 20 tsunami events have impacted the State of California in the past two centuries. California presents nontrivial challenges for assessing tsunami hazards, including a short historic record and the possibility of nearshore events with less than 20 min propagation times to the target coastlines. Here we present a brief history of earlier efforts to assess tsunami hazards in the State, and our methodology for developing the first generation inundation maps. Our results are based on worst case scenario events and suggest inundation heights up to 13 m. These maps are only to be used for emergency preparedness and evacuation planning. The present data record does not allow a more detailed quantitative assessment of tsunami risk; however, given the intense coastal land use and recreational activities along the coast, even a small hazard may pose high risk.

The 1998 Papua New Guinea tsunami disaster (over 2200 dead) cannot be simulated satisfactorily on the basis of the displacement field of its parent earthquake: In such simulations, runup amplitudes are too low, the extent of the devastated area too large, and the ratio of far- to near-field tsunami amplitudes also too large. Finally, the tsunami is computed to arrive at least 10 mn earlier than reconstructed from survivors' interviews. Rather, we show that evidence from underwater marine surveys, and from hydrophone records of hydroacoustic ("T") waves identify a slumping event as having taken place 13 minutes after the mainshock, at a site located 35 km offshore, and having involved a volume of 4 km³ of material. Simulations based on a such a source reproduce all main characteristics of the local runup distribution.

Computer simulation is an efficient tool to determine the extent and consequences of tsunami impact in naval and industrial port facilities and coastal urban developments, allowing the adequate design of coastal protection and an optimization in the use of the available response resources. Middle America Trench generated tsunamis are simulated assuming that the initial condition is an ocean water disturbance produced by an earthquake sea-floor deformation. Deep-water linear wave theory for the generation and far ocean propagation, and shallow water non-linear wave theory for the propagation near the shore and the interaction with the coast, are considered. To model the flooding and recession at the coast, non-fixed boundaries with discharges conditioned to the state of the water level at the borders, are used. The equations are solved through an explicit central finite-difference leap-frog algorithm for interconnected grids of different sizes. Two cases of tsunamis which may represent a low and a medium risk for Mexico, similar to the 1985 and 1995 events, were satisfactorily simulated. The impact of an extreme eventual tsunami of high risk but low probability of occurrence was also estimated. With this information, tsunami inundation maps showing water runup, flooding extension and eventual recurrence time for two main industrial ports of Mexico, including recommendations for urban development measures to reduce their vulnerability, were produced. This information also helps for hazard prevention planning and the design of adequate coastal protection for industrial and naval port installations.

A great earthquake occurred near the coast of southern Peru, about 110 miles (175 km) west of Arequipa, or about 370 miles (595 km) southeast of Lima at 20:33 UTC (3:33 PM local). A revised moment magnitude of 8.4 (Harvard) was computed for this earthquake, making this the largest earthquake in the past 25 years (Dengler 2001a). The earthquake was also associated with a large tsunami. Initial reports described 1-km inland inundation, 5 m of runup and extensive damage and flooding. It was determined that the tsunami affected 300 m of coastline with the highest runup concentrated along a 20 km stretch of coast near Camana. The event also created a transpacific tsunami that was recorded at tidal stations across the Pacific Basin with 10 to 40 cm waves amplitudes recorded in California, 70 cm in Hawaii and up to 50 cm in Japan. In all, 22 people were killed, 62 were reported as missing, and 3000 structures were damaged or destroyed.

The ability of a number of West Coast county and community emergency managers to understand and use tsunami warning and watch messages significantly improved between 1994 and 2001. A tsunami message event, a "warning", occurred in 1994 that allowed a baseline measurement to be taken of some local emergency managers' understanding of the tsunami warning process. The conclusions and recommendations coming out of the study in 1994 were used to develop a national program to improve this local understanding of the process. In June 2001 a second tsunami message event, a "watch", occurred that made it easy to repeat the original 1994 survey to measure any change in the local emergency managers' understanding of this process. Some of these findings were backed-up by another survey that had just been completed in May 2001 through interviews of these emergency managers. Because the second tsunami message event occurred in June 2001, the May 2001 survey could not ask the original 1994 questions and so was designed to indirectly measure any changes in the understanding of tsunami event messages in addition to its main purpose. This purpose was to try to assess the effect of the National Tsunami Hazard Mitigation Program (NTHMP) in local communities after 5 years. Responses indicate a significant improvement in the understanding of the tsunami watch/warning message process by local emergency managers. The NTHMP and partnership is a model for other hazardous events that require a warning process, building an information exchange network, and development of a public education process. This paper will be limited to discussion of the warning process improvement and related issues.

In the evening of November 3, 1994, a series of submarine landslides and associated waves destroyed the Pacific Arctic Railway Company (PARN) dock at Skagway, Alaska, killing one construction worker. Numerous geologic and hydrodynamic studies followed, in an effort to prove or disprove that construction failure was responsible for initiating the slide. We model the slide using two inundation models, the model known as TUNAMI—N2 (not TSUNAMI) developed at Tohoku University and the model VTCS—3 developed at the University of Southern California and now in use by NOAA and known as MOST. Both models when run under the same initial conditions and bathymetry provided consistent results about the hydrodynamic motions close to the PARN dock. The results qualitatively fit the eyewitness observations, using a combination of three slides, and suggest that the sliding started offshore along the fjord wall off the southern end of the dock and undermined the southern two thirds of the dock.

Tsunami inundation modeling of Grays Harbor and Pacific Counties was completed in May 1999 as part of our hazard assessment program. These maps are the basis for developing and testing emergency preparedness and evacuation plans. With the tsunami inundation areas identified, planning the evacuation routes became a priority. Two types of communities were identified: those with a single access road that increased evacuation times and those with safe nearby congregation areas. With evacuation routes and congregation areas delineated, state and county emergency managers installed tsunami warning and evacuation signs. Signs save lives by raising community awareness before a tsunami and by notifying people of appropriate evacuation routes during an event. A tsunami brochure with tsunami safety tips, NOAA Weather Radio information, and tsunami evacuation maps were developed and printed for release with the inundation maps. For those unable to evacuate before a tsunami strikes, officials distributed the book, Surviving a Tsunami—Lessons from Chile, Hawaii, and Japan. This tool allows local officials to show that tsunamis are survivable even if an evacuation isn't possible. The inundation maps and other materials were released at public forums. These presentations progressed from research findings and modeling to community tsunami preparedness issues. Finally, the tsunami communities are urged to apply these and other tsunami products to four areas: communications; warning reception and dissemination; public outreach and awareness; and administrative planning. Those communities that meet established criteria can be formally recognized as being a "Tsunami Ready Community".

In this study to produce innovation maps of study area, different types of data such as elevation and bathymetry of study area and Geographic Information Systems (GIS) have been used to determine risks areas on the coastline under the threat of tsunami.

Recent scientific research suggests the Pacifics Northwest could experience catastrophic earthquakes in the near future, both from distant and local sources, posing a significant threat to coastal communities. Damage could result from numerous earthquake-related hazards, such as severe ground shaking, soil liquefaction, landslides, land subsidence/uplift, and tsunami inundation. Because of their geographic location, ports and harbors are especially vulnerable to these hazards. Ports and harbors, however, are important components of many coastal communities, supporting numerous activities critical to the local and regional economy and possibly serving as vital post-event, response-recovery transportation links. A collaborative, multi-year initiative is underway to increase the resiliency of Pacific Northwest ports and harbors to earthquake and tsunami hazards, involving Oregon Sea Grant (OSG), Washington Sea Grant (WSG), the National Oceanic and Atmospheric Administration Coastal Services Center (CSC), and the U.S. Geological Survey Center for Science Policy (CSP). Specific products of this research, planning, and outreach initiative include a regional stakeholder issues and needs assessment, a community-based mitigation planning process, a Geographic Information System (GIS) — based vulnerability assessment methodology, an educational web-site and a regional data archive. This paper summarizes these efforts, including results of two pilot port-harbor community projects, one in Yaquina Bay, Oregon and the other in Sinclair Inlet, Washington. Finally, plans are outlined for outreach to other port and harbor communities in the Pacific Northwest and beyond, using "getting started" workshops and a web-based tutorial.

The National Tsunami Hazard Mitigation Program, a federal/state partnership between the National Oceanic and Atmospheric Administration (NOAA), the U.S. Geological Survey (USGS), the Federal Emergency Management Agency (FEMA) and the states of Alaska, California, Hawaii, Oregon, and Washington, was formed in 1997 to reduce the impacts of tsunamis to U.S. coastal communities. The program consists of three interdependent activities of hazard assessment, warning guidance, and mitigation. Updated information about our activities can be found at http://www.pmel.noaa.gov/tsunami-hazard/including the original implementation plan written in April 1996. An overview of the program will be given, including accomplishments and impact over the past 5 years, evaluations from a 5-year review held in August 2001, and future plans.

Over the past decade there has been a significant migration of people to the US coastlines as baby boomers either retire or have the means to purchase second homes. During a severe hurricane event, this increased population will make it even more difficult to evacuate everyone who might be in harms way; the only alternative will be to shelter those people someplace while the storm passes. Schools are usually the place chosen as shelters because of large open spaces available to house large numbers of people for short durations and because they are located in neighborhoods close to the populace. The very design features that make schools a good sheltering place are also the same features that make schools very vulnerable to failure under the very same hurricane conditions — open spaces, tall walls and long span roofs. However, there are some design considerations that can and should be made in schools that can mitigate the effects of these features and still provide the community with sheltering alternatives.

Eleven homes in Horry County, South Carolina were destructively tested to assess the state of existing buildings and evaluate recommendations for retrofit of existing homes to increase wind resistance. These homes were made available for testing by Horry County after their purchase as part of the Federal Emergency Management Agency's post Hurricane Floyd buyout program. Various tests were conducted on the homes, before and after retrofit options were put into place. The tests include roof sheathing nail withdrawal, debris impact, gable end pull-out failure, rafter connection uplift, and roof sheathing panel uplift. This paper details the preliminary results of the testing program.

A load and resistance methodology is presented to estimate the reduction in damage and the ensuing financial losses to residential structures associated with hurricanes. The methodology makes use of inspections of buildings to characterize the wind resistant features of a building both in its current state and after the building has been mitigated. The methodology is demonstrated with an example of a vulnerability and mitigation study for a single family residence in the Residential Construction Mitigation Program in the State of Florida.