Methodology for Assessment of Natural Hazard Vulnerability in U.s. Coastal Zone Using Remote Sensing

INTRODUCTIONtype of comprehensive database on disaster losses.
Coastal zone is defined as "the coastal watersNatural hazards such as hurricanes and earthquakes
(including the lands therein and thereunder) and thedo not have to become natural disasters. With proper
adjacent shorelands (including the waters therein andplanning, including proper environment management,
thereunder), strongly influenced by each other and inmuch of the risk can be reduced. The risks posed by
proximity to the shorelines of the several coastalnatural hazards in United States are exacerbated by
states, and includes islands, transitional and intertidalsocial and environmental trends such as rapid
areas, salt marshes, wetlands, and beaches." Coastalurbanization and unplanned human settlements, poorly
locations were some of the first settled in the country,engineered construction, lack of adequate
and have always accounted for a major percentageinfrastructure, poverty, and inadequate environmental
of the overall population. They were the primarypractices such as deforestation and land degradation.
centers for transportation, tourism, recreation,Given the significant costs of the nation’s
commercial fishing, and other industry. This coastalcatastrophic natural disasters, focus has shifted in
zone remains a crucial segment of the nation’srecent years to expand beyond emergency
overall economy. A variety of natural hazards regularlypreparedness and response to include a more
threaten this coastal zone. Severe meteorologicallong-term emphasis on disaster loss reduction. Hence it
events such as hurricanes, tropical cyclones, andrequires for a quantitative assessment of natural
nor’easters are particularly harsh on coastal areas,hazards vulnerability for coastal zone. This quantitative
often resulting in damages from high winds, stormassessment of natural hazards is aimed to minimize
surge, flooding, and shoreline erosion. Tsunamis, whoseeither an individual’s or a community’s
destructive force is characterized by potentiallyvulnerability to future disaster damages. Over the
devastating flood inundation, are uniquely coastalyears, progress has been made in reducing hazard
events resulting from offshore earthquakes, landslides,impacts through better predictions, forecasts, and
or volcanic activity. Coastal locations are alsowarnings, particularly for meteorological hazards such
subjected to the impacts of long-term hazards suchas coastal storms and floods. General improvements
as chronic coastal erosion, potential sea-level rise, andin hurricane and tsunami prediction, and river and lake
global climate change.level forecasting, have been possible using the latest in
Coastal hazard events can significantly affect or evencomputer modeling technology. NOAA’s National
alter the natural environment. Their impacts areWeather Service (NWS) is currently working with
generally not considered to be "disastrous" unless theyseveral new technological systems that are intended
involve damages to human populations andto significantly improve future flood forecasting
infrastructure. When people and property are notcapabilities. Though there were lot of techniques
present, hazards are merely natural processes thatavailable to assess vulnerability due to natural hazard
alter the environment. When people and property isquantitatively still it is necessary to acknowledge the
present then the impacts of hazards are viewed quitescientific and technological information needs
differently. The primary focus is no longer on thethroughout the various hazards-related disciplines and
natural processes associated with a major hazardintegration. Although significant progress has been
event, but instead on the disastrous results that can bemade in the research and science associated with
measured by lives lost, property damages, andnatural hazards during the past 20 years, and
economic and environmental impacts.improvements in technology and understanding about
The impacts of natural hazards are becomingnatural hazards and how to access its vulnerability
increasingly costly and devastating. Hazard impacts onquantitatively requires a real-time networked scientific
the natural environment become more devastatingdatabase.
because human development has altered the ability ofUniversities and research institutions (particularly the
natural systems to recover from such events. ExpertsNational Science Foundation), along with government
believe that the statistics on disaster losses continue toagencies such as NOAA and USGS that maintain
rise worldwide due to a combination of factors thatscientific hazards-related responsibilities, have
include a rise in the number of hazard events due tocontributed to advances in the scientific study of
global climate change or natural cyclical trends, and annatural hazards. There is now more quantitative
increase in human exposure in hazardous locations.information available about the origins and behavior of
Some of the decrease in disaster damages worldwidehazard events but the concept of integration of the
could also be the result of improvements in disasteravailable data sets is lagged.
monitoring and reporting capabilities, particularly inThis study is to integrate all the fields acting in coastal
developing countries. But disaster loss increases in thezone for the assessment of vulnerability. Maps
United States seem to be most closely tied todelineating hazard-prone areas at national, state, and
increased human exposure in high risk areas such aslocal levels are needed to provide more
the nation’s coasts.comprehensive hazards assessment using information
The United States has an expansive and diverseon a variety of natural phenomena, including coastal
coastline that supports a disproportionate percentagestorms, floods, tsunamis, hurricanes, typhoons,
of the nation’s population. The nation’s 451landslides, wildfires, drought, earthquakes, etc. Much of
coastal counties contain just over 50 percent of thethis information already exists, but issues such as data
U.S. population, yet only account for about 20 percentintegration, compatibility, scales, accuracy, and resolution
of the total U.S. land area. During the last decade, 17 ofneed to be addressed to make the information useful
the 20 fastest growing counties were located alongat the local level. Better methodologies and models are
the coast. In addition, 19 of the 20 most denselyalso needed for conducting hazard vulnerability
populated counties in the nation are coastal counties.assessments that can incorporate highly variable local
These coastal counties possess economic gainconditions and characteristics. This calls for the site
through natural resources, maritime trade andspecific models for better estimates.
commerce. These coastal counties also possessComputer-based geographic information systems
economic loss due to the natural hazards,could be used to analyze hazards information and
overexploitation and exponential population growth. Anprovide national risk assessment data to state and
assessment of both the economic gain and economiclocal governments in quick and easy manner. Specific
loss is briefly discussed as follows.models could be generated by using the GIS software.
Economic gain in U.S. coastal zoneNew high-resolution remote sensing capabilities could
Nature article (May 1997), a group of ecologistsbe examined for use in large-scale risk and vulnerability
estimated the value on ecosystem in the coastal zone.assessment. Hence, remote Sensing and GIS is to be
They estimated that the worth of the services forintergrated and modeled for the assessment of
marine ecosystems is approximately $21 trillion perquantitative natural hazard vulnerability.
year. According to Sea Technology magazine, theImprovements in monitoring, data collection, and data
value of goods and services sold by the ocean/marineprocessing account for most of the advancements
industry was estimated in 1995 as $60 billion annually.made in short-term weather-related forecasting. Better
Offshore oil and gas production has become verymodeling capabilities, along with a more thorough
important and the 1996 value was more than $8 billionunderstanding of variables, such as global climate
and the annual offshore production is increasing.change and sea-level rise, are needed to improve
According to the National Oceanic and Atmosphericlong-range forecasting and planning for coastal hazard
Administration (NOAA), 77 million pounds (meat weight)impacts.
of shellfish were harvested from U.S. coastal waters inGIS integration / modeling for natural hazard
1995, with a dockside value of $200 million.vulnerability
Current NOAA estimates concerning the recreationalGIS is one of the powerful tools which can be used
uses of U.S. coastal areas includes: approximately 94for the assessment of Natural Hazards Vulnerability
million people boat and fish annually; the average(NHV). Due to these techniques, natural hazard
American spends 10 recreational days on the coastmapping and vulnerability assessment could be
each year; The coasts (excluding the Great Lakesperformed for the coastal zone. These maps will help
coastline) support 25,500 recreational facilities; Morethe authorities for quick assessment of potential
than 180 million Americans visited ocean and bayimpact of a natural hazard and initiation of appropriate
beaches in 1993; Recreational fishing contributes $13.5measures for reducing the impact. This data will help
billion annually to the U.S.economy; Coastal recreationthe planners and decision-makers to take positive
and tourism generate $8 to $12 billion annually.steps in time.
Economic loss in U.S. coastal zoneGIS applications in the coastal zone are diversified and
Disaster losses in the United States coastal zone arecase-based. Applications studies such as (a) coastal
currently estimated conservatively at $50 billionmapping, (b) environmental monitoring, (c) coastal
annually. The disaster loss between 1975 and 1994 isprocess modelling, (d) navigation and port facilities
estimated as $500 billion. 80 percent of the lossesmanagement, (e) coastal environmental / hazard
were imposed by meteorological events and 10assessment, (f) coastal management / strategic
percent were the result of earthquakes andplanning, and (g) coastal ecological modeling could be
volcanoes. A great earthquake (magnitude 8 or larger)done through GIS.
has not struck a major metropolitan area since theCoastal Mapping is mainly focused on thematic
1906 San Francisco earthquake. An extreme ormapping in the coastal zone, such as mapping
catastrophic hurricane (Class 4 or 5) has not directlychlorophyll concentration using TM data (Chen et al.
struck a major urban area since the one that hit Miami,1996). Environmental monitoring is one of the routine
Florida, in 1926. Yet even without such disasters, whichtasks in CZM, which include monitoring water quality
might create losses well over $100 billion, the overalland habitat/biodiversity, and beach watch. Coastal
costs of natural hazards, such as extreme weather,processes modeling of physical environment change in
drought, and wildfires, are estimated at $54 billion perthe coastal zone includes the simulation of effects of
year for the past 5 years, or approximately $1 billionsea-level rise (Ruth and Pieper 1994, Grossman and
per week. In the United States, the direct costs toEberhardt 1992, Zeng and Cowell 1998, 1999, Hennecke
repair the damage average about $20 billion per year,2000), the assessment of human intervention of
of which over $15 billion is due to tornadoes, hurricanes,shoreline change (Huang et al. 1999), the use of
floods and earthquakes.historical data to predict future coastline change (Sims
The FEMA coastal erosion study conducted by Theet al. 1995) and the study of beach morphodynamics
Heinz Center for Science, Economics and the(Humphries and Ligdas, 1997). There are another two
Environment estimates that approximately 25 percentsubcategories of the applications of hazards, namely,
of homes and other structures within 500 feet of theshort-term and long-term tasks. The former is
U.S. coastline and the shorelines of the Great Lakesexemplified with monitoring and predicting oil spill
will fall victim to the effects of erosion within the next(Belore, 1990), while the latter is demonstrated by
60 years. Especially hard hit will be areas along thecoastal hazard / vulnerability assessment due to
Atlantic and Gulf of Mexico coastlines, which areclimate change (Lee et al. 1992, Sims, et al., 1995;
expected to account for 60 percent of nationwideDeniels et al. 1996, Hickey et al. 1997, Zeng and Cowell
losses. The report estimates that costs to U.S.1999, Hennecke et al. 2000, Esnard et al. 2001). Coastal
homeowners will average more than a half billionmanagement / strategic planning involve assessing
dollars per year, and that additional development in highsustainability of the environment, social and economic
erosion areas will lead to higher losses. Thirty-fourviability. The above said studies carried out in coastal
floods have been reported in Wake County (datazone are to be integrated using remote sensing and
source: NDCD and SHELDUS). The total coastline ofGIS for analysis.
mapped shoreline of Gulf of Mexico coast is aboutThe categories of GIS applications in coastal zone
8058 km out of which 3387 kms is in very high risk,could be broadly categorized into three levels.a) Level
1056 kms is in high risk, 2968 km is in moderately risk1: as data management and mapping tools,b) Level 2:
and 547 kms is in low risk category due to sea levelas basic data analysis (query) and mapping tools,
rise. So the 42 % of the coast line is in high risk, 37 %andc) Level 3: as decision-supporting tools (modelling /
moderate risk and 8 % low risk (Robert Thieler et.al.simulation).
2001).Most current implementations of Coastal GIS are still at
Hurricane Mitch, one of the most powerful andLevel 1 and Level 2. It is expected that Level 3
damaging storms experienced in Central America,implementations will rapidly increase in the near future
struck between 26 October and 1 November 1998. Aas the continuing improvement in GIS functions and
Category V hurricane, the event was characterizedmore user-friendly interface become available in the
by intensive rainfall and high winds, dumping amarket. Hence for the study of Quantitative
year’s worth of precipitation in less than one weekAssessment of Natural Hazard Vulnerability Level 3
on the region, causing the overflow of rivers, floods,application is to be adopted.
mudslides and landslides. Thousands of people wereThe two basic approach / analysis, which should be
killed and left homeless. Mitch caused billions of dollarsfollowed for geospatial database development were
of damage, and left huge tasks of reconstruction,given below.
resulting in the loss of decades of development effortsIntegrated approach:a) integration of different level of
in the region.application,b) integration of vector and raster (data and
The Economic Commission for Latin America and thefunctions),c) integration of knowledge of different
Caribbean (ECLAC) estimates that the direct cost ofexpertise, andd) integration of different scales in time
replacing the lost and damaged infrastructure in theand space.
region after Hurricane Mitch is some US$5,000 millionBecause of the nature of integration, GIS applications
(Caballeros, 1999).should consider long-term integration. This includes the
Recent large-scale disasters such as Hurricane Mitchvertical integration that involves different application
and Georges, and the earthquake in Armenia,(and potential) levels, and horizontal integration that
Colombia have demonstrated the vulnerability ofinvolves other interest groups. Therefore, issues must
society. It is widely recognized that recent populationbe addressed from database design, data sharing to
growth, rapid urbanization and the socioeconomictool-making (analysis functions) and experience sharing.
structure in Central America have increasedMulti-criteria analysisa) multi - factors controls
vulnerability of these countries to natural hazards.Since coastal system has a complex hierarchical
These disasters faced by the inhabitants both bystructure with multi-forcing exerting on each of
natural and anthropological effects lead to thesubsystem, no mater which aspect of the system to
formation of legislation / laws to govern.be investigated, multi-variable analysis is an essential
Legislation & major acts in U.S. Coastal Zonemethods in the coastal environment.b) multi - discipline
The economic loss and economic yield as such felt byapproach for decision Other than the multi-factors,
the inhabitants of the Earth has resulted in thethere are multiple interest groups of coastal
formation of legislation. This legislation is framed for thecommunity, therefore, good solutions to any coastal
sustainable use of the available natural resources.issues can only be derived from multidiscipline
When the loss is severe or the gain is enormous; theapproach.
laws needs some revision hence they were amendedOutput of the analysis
periodically. Some of the Laws and Acts pertaining toI. Historical and real-time information with respect to
U.S. coastal zone were National Environmental Policynatural hazards will be gathered by satellite remote
Act, Clean water Act, Marine Protection, Researchsensing, aerial photographs and by other conventional
and Sanctuaries Act, Ocean Dumping Act of 1972,means and integrated with GIS RDBMS. This results in
Water Resources Development Act of 1996, Coastalan extensive geo- database.
Zone Management Act of 1972, Marine MammalII. Through the modeling technique and by using the GIS
Protection Act of 1972, Magnuson-Stevens FisheryRDBMS we can evaluate the likelihood of experiencing
Conservation and Management Act of 1976specific natural hazard in the future, and an estimation
Endangered Species Act 1973, Nation wise Invasiveof intensity and probable level of impact.
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 and
Outer Continental Shelf Lands Act, Resourcedamage 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 occurrence
Hence in order to amend these laws the integration inas a whole (event parameter) or in terms of the
different fields is attempted and discussed as follows.effect the occurrence would have at a particular
RESULTS AND DISCUSSIONlocation (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 action,
economic assets and may cause disaster. They aremeterology, wind action etc). The values that will be
caused by meteorological, biological, geological, seismic,given in the attribute columns could be calculated with
hydrological, or conditions or processes in the naturalthe help of the equation 1 modeled in GIS environment.
environment. Hazard assessment is the process ofNatural hazard = (Wgeology + Wslope + Wwind +
estimating, for defined areas, the probabilities of theWmeteo + Wsiesmisivity
occurrence of potentially - damaging phenomenon of+ Wgeomorphology + Wetc…) (1)
given magnitudes within a specified period of time.Based on the above formula, natural hazard
Hazard assessment involves analysis of formal andvulnerability values could be retrieved by clicking on
informal historical records, and skilled interpretation ofany land parcels from the coastal zone map. Such kind
existing meteorological, topographical, geological,of values will have no meanings for the end users. To
geomorphologic, hydrological, and land-use maps.make the result more acceptable, a separate domain
Office of United Nations Development Reliefis to be created in which the resultant values will be
Organization (UNDRO), defines the term vulnerabilitydivided into three classes: very high, high, moderate and
as: “The degree of loss to a given element or setlow hazard areas
of 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 element atpossess these five steps –
risk, and accordingly may be measured as a ratio of• identification of natural hazards that could impact
the numbers of persons killed or injured to the totalthe community,
population, as a repair cost or as the degree of• assessment of the community’s vulnerability to
physical damage defined on an appropriate scale. In anatural hazards,
large number of elements, like building stock, it may be• assessment of the community’s capability to
defined in terms of the proportion of buildingsrespond 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 strategies that
from various sources concerning both direct andcan be implemented to reduce future vulnerability.
indirect losses, short- and long-term effects. It involvesVI. By using all the above factors site specific models
determining not only what has happened and whatfor the assessment of natural hazard vulnerability
assistance might be needed, but also definingcould be generated using GIS for U.S. coastal zone.
objectives and how relevant assistance can actuallyThis will serve as an input for further amendment of
be provided to the victims. It requires attention to bothlegislation concerned with U.S coastal zone.
short-term needs and long-term implications.CONCLUSION
The United States is becoming more vulnerable toU.S. coastal counties possess economic gain through
natural hazards mostly because of changes innatural resources, maritime trade and commerce and
population and national wealth density. Due to this,economic loss through natural hazards, overexploitation
people and infrastructure have become concentratedand exponential population growth. About 80 percent
in disaster-prone areas. Natural Hazards threaten theof the losses were by meteorological events and 10
sustainable development of United States, destroyingpercent were by earthquakes and volcanoes. Hence in
years of development efforts and investments, placingorder to minimize the loss due to natural hazard a
new demands on society for reconstruction andcomputer based geospatial database methodology is
rehabilitation, and shifting development priorities awayadopted for natural hazards information retrieval and
from long-term goals while immediate needs are met.to provide national risk assessment data to the state
For most of the 20th century, the United States hasand local governments. Site specific models were
largely spared the expense for catastrophic naturalproposed for U.S. coastal zone by integrating GIS
disaster. Significant progress has been made insoftware and high-resolution remote sensing to
understanding the various impacts that hazardsquantify the large-scale risk and vulnerability. This
produce on human and natural environments.modeling study could also be applied to developing
Numerous research activities have been undertakencountries such as India, Pakistan, Srilanka etc. for the
following the major hazard events of the past fewnatural hazard vulnerability assessment in their coastal
years. Unfortunately, much of this research iszones.
piecemeal and has not been incorporated into any