Methodology for assessment of natural hazard vulnerability in U.S. coastal zone using Remote Sensing

INTRODUCTIONdo not have to become natural disasters. With
Coastal zone is defined as "the coastal watersproper planning, including proper environment
(including the lands therein and thereunder) and themanagement, much of the risk can be reduced. The
adjacent shorelands (including the waters therein andrisks posed by natural hazards in United States are
thereunder), strongly influenced by each other and inexacerbated by social and environmental trends such
proximity to the shorelines of the several coastalas rapid urbanization and unplanned human
states, and includes islands, transitional and intertidalsettlements, poorly engineered construction, lack of
areas, salt marshes, wetlands, and beaches." Coastaladequate infrastructure, poverty, and inadequate
locations were some of the first settled in theenvironmental practices such as deforestation and
country, and have always accounted for a majorland degradation.
percentage of the overall population. They were theGiven the significant costs of the nation's
primary centers for transportation, tourism,catastrophic natural disasters, focus has shifted in
recreation, commercial fishing, and other industry. Thisrecent years to expand beyond emergency
coastal zone remains a crucial segment of the nation'spreparedness and response to include a more
overall economy. A variety of natural hazardslong-term emphasis on disaster loss reduction. Hence
regularly threaten this coastal zone. Severeit requires for a quantitative assessment of natural
meteorological events such as hurricanes, tropicalhazards vulnerability for coastal zone. This
cyclones, and nor'easters are particularly harsh onquantitative assessment of natural hazards is aimed
coastal areas, often resulting in damages from highto minimize either an individual's or a community's
winds, storm surge, flooding, and shoreline erosion.vulnerability to future disaster damages. Over the
Tsunamis, whose destructive force is characterizedyears, progress has been made in reducing hazard
by potentially devastating flood inundation, areimpacts through better predictions, forecasts, and
uniquely coastal events resulting from offshorewarnings, particularly for meteorological hazards such
earthquakes, landslides, or volcanic activity. Coastalas coastal storms and floods. General improvements
locations are also subjected to the impacts ofin hurricane and tsunami prediction, and river and lake
long-term hazards such as chronic coastal erosion,level forecasting, have been possible using the latest
potential sea-level rise, and global climate change.in computer modeling technology. NOAA's National
Coastal hazard events can significantly affect or evenWeather Service (NWS) is currently working with
alter the natural environment. Their impacts areseveral new technological systems that are intended
generally not considered to be "disastrous" unlessto significantly improve future flood forecasting
they involve damages to human populations andcapabilities. Though there were lot of techniques
infrastructure. When people and property are notavailable to assess vulnerability due to natural hazard
present, hazards are merely natural processes thatquantitatively still it is necessary to acknowledge the
alter the environment. When people and property isscientific and technological information needs
present then the impacts of hazards are viewedthroughout the various hazards-related disciplines and
quite differently. The primary focus is no longer onintegration. Although significant progress has been
the natural processes associated with a major hazardmade in the research and science associated with
event, but instead on the disastrous results that cannatural hazards during the past 20 years, and
be measured by lives lost, property damages, andimprovements in technology and understanding about
economic and environmental impacts.natural hazards and how to access its vulnerability
The impacts of natural hazards are becomingquantitatively requires a real-time networked scientific
increasingly costly and devastating. Hazard impacts ondatabase.
the natural environment become more devastatingUniversities and research institutions (particularly the
because human development has altered the abilityNational Science Foundation), along with government
of natural systems to recover from such events.agencies such as NOAA and USGS that maintain
Experts believe that the statistics on disaster lossesscientific hazards-related responsibilities, have
continue to rise worldwide due to a combination ofcontributed to advances in the scientific study of
factors that include a rise in the number of hazardnatural hazards. There is now more quantitative
events due to global climate change or natural cyclicalinformation available about the origins and behavior of
trends, and an increase in human exposure inhazard events but the concept of integration of the
hazardous locations.available data sets is lagged.
Some of the decrease in disaster damagesThis study is to integrate all the fields acting in
worldwide could also be the result of improvementscoastal zone for the assessment of vulnerability.
in disaster monitoring and reporting capabilities,Maps delineating hazard-prone areas at national, state,
particularly in developing countries. But disaster lossand local levels are needed to provide more
increases in the United States seem to be mostcomprehensive hazards assessment using information
closely tied to increased human exposure in high riskon a variety of natural phenomena, including coastal
areas such as the nation's coasts.storms, floods, tsunamis, hurricanes, typhoons,
The United States has an expansive and diverselandslides, wildfires, drought, earthquakes, etc. Much
coastline that supports a disproportionate percentageof this information already exists, but issues such as
of the nation's population. The nation's 451 coastaldata integration, compatibility, scales, accuracy, and
counties contain just over 50 percent of the U.S.resolution need to be addressed to make the
population, yet only account for about 20 percent ofinformation useful at the local level. Better
the total U.S. land area. During the last decade, 17 ofmethodologies and models are also needed for
the 20 fastest growing counties were located alongconducting hazard vulnerability assessments that can
the coast. In addition, 19 of the 20 most denselyincorporate highly variable local conditions and
populated counties in the nation are coastal counties.characteristics. This calls for the site specific models
These coastal counties possess economic gainfor better estimates.
through natural resources, maritime trade andComputer-based geographic information systems
commerce. These coastal counties also possesscould be used to analyze hazards information and
economic loss due to the natural hazards,provide national risk assessment data to state and
overexploitation and exponential population growth.local governments in quick and easy manner. Specific
An assessment of both the economic gain andmodels could be generated by using the GIS
economic loss is briefly discussed as follows.software. New high-resolution remote sensing
Economic gain in U.S. coastal zonecapabilities could be examined for use in large-scale
Nature article (May 1997), a group of ecologistsrisk and vulnerability assessment. Hence, remote
estimated the value on ecosystem in the coastalSensing and GIS is to be intergrated and modeled for
zone. They estimated that the worth of the servicesthe assessment of quantitative natural hazard
for marine ecosystems is approximately $21 trillionvulnerability.
per year. According to Sea Technology magazine, theImprovements in monitoring, data collection, and data
value of goods and services sold by the oceanprocessing account for most of the advancements
marine industry was estimated in 1995 as $60 billionmade in short-term weather-related forecasting.
annually. Offshore oil and gas production has becomeBetter modeling capabilities, along with a more
very important and the 1996 value was more thanthorough understanding of variables, such as global
$8 billion and the annual offshore production isclimate change and sea-level rise, are needed to
increasing. According to the National Oceanic andimprove long-range forecasting and planning for
Atmospheric Administration (NOAA), 77 million poundscoastal hazard impacts.
(meat weight) of shellfish were harvested from U.S.GIS integration / modeling for natural hazard
coastal waters in 1995, with a dockside value of $200vulnerability
million.GIS is one of the powerful tools which can be used
Current NOAA estimates concerning the recreationalfor the assessment of Natural Hazards Vulnerability
uses of U.S. coastal areas includes: approximately 94(NHV). Due to these techniques, natural hazard
million people boat and fish annually; the averagemapping and vulnerability assessment could be
American spends 10 recreational days on the coastperformed for the coastal zone. These maps will help
each year; The coasts (excluding the Great Lakesthe authorities for quick assessment of potential
coastline) support 25,500 recreational facilities; Moreimpact of a natural hazard and initiation of appropriate
than 180 million Americans visited ocean and baymeasures for reducing the impact. This data will help
beaches in 1993; Recreational fishing contributes $13.5the planners and decision-makers to take positive
billion annually to the U.S.economy; Coastal recreationsteps in time.
and tourism generate $8 to $12 billion annually.GIS applications in the coastal zone are diversified and
Economic loss in U.S. coastal zonecase-based. Applications studies such as (a) coastal
Disaster losses in the United States coastal zone aremapping, (b) environmental monitoring, (c) coastal
currently estimated conservatively at $50 billionprocess modelling, (d) navigation and port facilities
annually. The disaster loss between 1975 and 1994 ismanagement, (e) coastal environmental / hazard
estimated as $500 billion. 80 percent of the lossesassessment, (f) coastal management / strategic
were imposed by meteorological events and 10planning, and (g) coastal ecological modeling could be
percent were the result of earthquakes anddone through GIS.
volcanoes. A great earthquake (magnitude 8 orCoastal Mapping is mainly focused on thematic
larger) has not struck a major metropolitan area sincemapping in the coastal zone, such as mapping
the 1906 San Francisco earthquake. An extreme orchlorophyll concentration using TM data (Chen et al.
catastrophic hurricane (Class 4 or 5) has not directly1996). Environmental monitoring is one of the routine
struck a major urban area since the one that hittasks in CZM, which include monitoring water quality
Miami, Florida, in 1926. Yet even without suchand habitat/biodiversity, and beach watch. Coastal
disasters, which might create losses well over $100processes modeling of physical environment change in
billion, the overall costs of natural hazards, such asthe coastal zone includes the simulation of effects of
extreme weather, drought, and wildfires, aresea-level rise (Ruth and Pieper 1994, Grossman and
estimated at $54 billion per year for the past 5 years,Eberhardt 1992, Zeng and Cowell 1998, 1999,
or approximately $1 billion per week. In the UnitedHennecke 2000), the assessment of human
States, the direct costs to repair the damageintervention of shoreline change (Huang et al. 1999),
average about $20 billion per year, of which over $15the use of historical data to predict future coastline
billion is due to tornadoes, hurricanes, floods andchange (Sims et al. 1995) and the study of beach
earthquakes.morphodynamics (Humphries and Ligdas, 1997). There
The FEMA coastal erosion study conducted by Theare another two subcategories of the applications of
Heinz Center for Science, Economics and thehazards, namely, short-term and long-term tasks. The
Environment estimates that approximately 25 percentformer is exemplified with monitoring and predicting
of homes and other structures within 500 feet ofoil spill (Belore, 1990), while the latter is demonstrated
the U.S. coastline and the shorelines of the Greatby coastal hazard / vulnerability assessment due to
Lakes will fall victim to the effects of erosion withinclimate change (Lee et al. 1992, Sims, et al., 1995;
the next 60 years. Especially hard hit will be areasDeniels et al. 1996, Hickey et al. 1997, Zeng and
along the Atlantic and Gulf of Mexico coastlines,Cowell 1999, Hennecke et al. 2000, Esnard et al.
which are expected to account for 60 percent of2001). Coastal management / strategic planning
nationwide losses. The report estimates that costs toinvolve assessing sustainability of the environment,
U.S. homeowners will average more than a half billionsocial and economic viability. The above said studies
dollars per year, and that additional development incarried out in coastal zone are to be integrated using
high erosion areas will lead to higher losses.remote sensing and GIS for analysis.
Thirty-four floods have been reported in WakeThe categories of GIS applications in coastal zone
County (data source: NDCD and SHELDUS). The totalcould be broadly categorized into three levels.a) Level
coastline of mapped shoreline of Gulf of Mexico1: as data management and mapping tools,b) Level 2:
coast is about 8058 km out of which 3387 kms is inas basic data analysis (query) and mapping tools,
very high risk, 1056 kms is in high risk, 2968 km is inandc) Level 3: as decision-supporting tools (modelling /
moderately risk and 547 kms is in low risk categorysimulation).
due to sea level rise. So the 42 % of the coast line isMost current implementations of Coastal GIS are still
in high risk, 37 % moderate risk and 8 % low riskat Level 1 and Level 2. It is expected that Level 3
(Robert Thieler et.al. 2001).implementations will rapidly increase in the near future
Hurricane Mitch, one of the most powerful andas the continuing improvement in GIS functions and
damaging storms experienced in Central America,more user-friendly interface become available in the
struck between 26 October and 1 November 1998. Amarket. Hence for the study of Quantitative
Category V hurricane, the event was characterizedAssessment of Natural Hazard Vulnerability Level 3
by intensive rainfall and high winds, dumping a year'sapplication is to be adopted.
worth of precipitation in less than one week on theThe two basic approach / analysis, which should be
region, causing the overflow of rivers, floods,followed for geospatial database development were
mudslides and landslides. Thousands of people weregiven below.
killed and left homeless. Mitch caused billions of dollarsIntegrated approach:a) integration of different level
of damage, and left huge tasks of reconstruction,of application,b) integration of vector and raster
resulting in the loss of decades of development(data and functions),c) integration of knowledge of
efforts in the region.different expertise, andd) integration of different
The Economic Commission for Latin America and thescales in time and space.
Caribbean (ECLAC) estimates that the direct cost ofBecause of the nature of integration, GIS applications
replacing the lost and damaged infrastructure in theshould consider long-term integration. This includes the
region after Hurricane Mitch is some US$5,000 millionvertical integration that involves different application
(Caballeros, 1999).(and potential) levels, and horizontal integration that
Recent large-scale disasters such as Hurricane Mitchinvolves other interest groups. Therefore, issues
and Georges, and the earthquake in Armenia,must be addressed from database design, data
Colombia have demonstrated the vulnerability ofsharing to tool-making (analysis functions) and
society. It is widely recognized that recent populationexperience sharing.
growth, rapid urbanization and the socioeconomicMulti-criteria analysisa) multi - factors controls
structure in Central America have increasedSince coastal system has a complex hierarchical
vulnerability of these countries to natural hazards.structure with multi-forcing exerting on each of
These disasters faced by the inhabitants both bysubsystem, no mater which aspect of the system to
natural and anthropological effects lead to thebe investigated, multi-variable analysis is an essential
formation of legislation / laws to govern.methods in the coastal environment.b) multi - discipline
Legislation & major acts in U.S. Coastal Zoneapproach for decision Other than the multi-factors,
The economic loss and economic yield as such felt bythere are multiple interest groups of coastal
the inhabitants of the Earth has resulted in thecommunity, therefore, good solutions to any coastal
formation of legislation. This legislation is framed forissues can only be derived from multidiscipline
the sustainable use of the available natural resources.approach.
When the loss is severe or the gain is enormous; theOutput of the analysis
laws needs some revision hence they were amendedI. Historical and real-time information with respect to
periodically. Some of the Laws and Acts pertaining tonatural hazards will be gathered by satellite remote
U.S. coastal zone were National Environmental Policysensing, aerial photographs and by other conventional
Act, Clean water Act, Marine Protection, Researchmeans and integrated with GIS RDBMS. This results in
and Sanctuaries Act, Ocean Dumping Act of 1972,an extensive geo- database.
Water Resources Development Act of 1996, CoastalII. Through the modeling technique and by using the
Zone Management Act of 1972, Marine MammalGIS RDBMS we can evaluate the likelihood of
Protection Act of 1972, Magnuson-Stevens Fisheryexperiencing specific natural hazard in the future, and
Conservation and Management Act of 1976an estimation of intensity and probable level of
Endangered Species Act 1973, Nation wise Invasiveimpact.
Species Act of 1996, Oil Pollution Act of 1990,Each natural hazard will be evaluated for three
Comprehensive environmental response,characteristics:
compensation, and liability act of 1980, Rivers and1. Likelihood of Occurrence, i.e., expected frequency;
Harbor Act of 1899, The Submerged Lands Act of2. Likely Range of Impact, i.e., predictable size and
1953, The Fish and Wildlife Coordination Act of 1934,location of impact; and
Land and Water Conservation Fund Act of 1965,3. Probable Level of Impact, i.e., estimated strength
Outer Continental Shelf Lands Act, Resourceand damage potential.
Conservation and Recovery Act of 1976 and TheIII. The level of severity of natural hazards will be
Coastal Barriers Resources Act of 1982.quantified in terms of the magnitude of the
Hence in order to amend these laws the integration inoccurrence as a whole (event parameter) or in terms
different fields is attempted and discussed as follows.of the effect the occurrence would have at a
RESULTS AND DISCUSSIONparticular location (site parameter).
Assessment of Natural HazardIV. For quantitative natural hazard vulnerability, some
Natural hazard is a phenomenon which occurs inweight value has to be added to the attribute column
proximity and poses a threat to people, structures or(slope, subsurface geology, current action, wave
economic assets and may cause disaster. They areaction, meterology, wind action etc). The values that
caused by meteorological, biological, geological,will be given in the attribute columns could be
seismic, hydrological, or conditions or processes in thecalculated with the help of the equation 1 modeled in
natural environment. Hazard assessment is theGIS environment.
process of estimating, for defined areas, theNatural hazard = (Wgeology + Wslope + Wwind +
probabilities of the occurrence of potentially -Wmeteo + Wsiesmisivity
damaging phenomenon of given magnitudes within a+ Wgeomorphology + Wetc…) (1)
specified period of time. Hazard assessment involvesBased on the above formula, natural hazard
analysis of formal and informal historical records, andvulnerability values could be retrieved by clicking on
skilled interpretation of existing meteorological,any land parcels from the coastal zone map. Such
topographical, geological, geomorphologic, hydrological,kind of values will have no meanings for the end
and land-use maps.users. To make the result more acceptable, a
Office of United Nations Development Reliefseparate domain is to be created in which the
Organization (UNDRO), defines the term vulnerabilityresultant values will be divided into three classes: very
as: "The degree of loss to a given element or set ofhigh, high, moderate and low hazard areas
elements at risk resulting from the occurrence of aWeights Class:
natural phenomenon of a given magnitude. It isValues below than 30 Low hazard Area
expressed on a scale from 0 (no damage) to 1 (totalValues between 30-40 Moderate Hazard Area
damage)". The vulnerability of an element is usuallyValues between 40-50 High Hazard Area
expressed as a percentage loss (or as a valueValues between 50-60 Very High Hazard Area
between 0 and 1) for a given hazard severity level.V. Hazard mitigation plan is to be developed and it will
The measure of loss used depends on the elementpossess these five steps -
at risk, and accordingly may be measured as a ratio• identification of natural hazards that could
of the numbers of persons killed or injured to theimpact the community,
total population, as a repair cost or as the degree of• assessment of the community's
physical damage defined on an appropriate scale. In avulnerability to natural hazards,
large number of elements, like building stock, it may• assessment of the community's capability
be defined in terms of the proportion of buildingsto respond to a natural disaster,
experiencing some particular level of damage.• assessment of the community's current
Assessment is an interdisciplinary process under-takenpolicies and ordinances that affect hazard mitigation,
in phases and involving on-the-spot surveys and theand
collation, evaluation and interpretation of information• development of hazard mitigation
from various sources concerning both direct andstrategies that can be implemented to reduce future
indirect losses, short- and long-term effects. Itvulnerability.
involves determining not only what has happened andVI. By using all the above factors site specific models
what assistance might be needed, but also definingfor the assessment of natural hazard vulnerability
objectives and how relevant assistance can actuallycould be generated using GIS for U.S. coastal zone.
be provided to the victims. It requires attention toThis will serve as an input for further amendment of
both short-term needs and long-term implications.legislation concerned with U.S coastal zone.
The United States is becoming more vulnerable toCONCLUSION
natural hazards mostly because of changes inU.S. coastal counties possess economic gain through
population and national wealth density. Due to this,natural resources, maritime trade and commerce and
people and infrastructure have become concentratedeconomic loss through natural hazards,
in disaster-prone areas. Natural Hazards threaten theoverexploitation and exponential population growth.
sustainable development of United States, destroyingAbout 80 percent of the losses were by
years of development efforts and investments,meteorological events and 10 percent were by
placing new demands on society for reconstructionearthquakes and volcanoes. Hence in order to
and rehabilitation, and shifting development prioritiesminimize the loss due to natural hazard a computer
away from long-term goals while immediate needsbased geospatial database methodology is adopted
are met. For most of the 20th century, the Unitedfor natural hazards information retrieval and to
States has largely spared the expense forprovide national risk assessment data to the state
catastrophic natural disaster. Significant progress hasand local governments. Site specific models were
been made in understanding the various impacts thatproposed for U.S. coastal zone by integrating GIS
hazards produce on human and natural environments.software and high-resolution remote sensing to
Numerous research activities have been undertakenquantify the large-scale risk and vulnerability. This
following the major hazard events of the past fewmodeling study could also be applied to developing
years. Unfortunately, much of this research iscountries such as India, Pakistan, Srilanka etc. for the
piecemeal and has not been incorporated into anynatural hazard vulnerability assessment in their coastal
type of comprehensive database on disaster losses.zones.
Natural hazards such as hurricanes and earthquakes