The New York City Hazard Vulnerability Index (NYCHVI):
Developing a GIS Based Hazard Vulnerability
Assessment Tool for the Five Boroughs of New York City
ABSTRACT:
With its 600 miles of coastline, the City of New York, a densely populated
financial and cultural center, is susceptible to a range of natural (e.g.,
hurricane, flooding, extreme heat) and human-induced (e.g., structural
collapse, utility failure, disease outbreak) hazards. Certain groups (e.g., small children,
elderly, non English speakers and those with health conditions) are more
vulnerable to hazards than others.
These groups may be determined using demographic (Census) and public
health (SPARCS) data. Various hazard
specific approaches were reviewed. The hazard-of-place model is an integrated
approach to hazard vulnerability assessment that utilizes both biophysical and
socioeconomic indicators in spatial terms.
The Human Vulnerability Assessment (HVA) model was created by the
Geospatial Research, Analysis, and Services Program (GRASP) at the Centers for
Disease Control and Prevention (CDC) and is composed of the following
socioeconomic indices: Personal and Household, Housing and Transportation,
Economic, and Race and Ethnicity.
Through adaptation of HVA metrics, the addition of a health metric as
well as Special Needs and Life Line overlays denoted by the Emergency
Management Symbol set, the New York City Hazard Vulnerability Index (NYCHVI)
was created to satisfy the socioeconomic component of a hazard of place model
for a metropolitan center such as New York City. In addition, the Federal Emergency
Management Agency (FEMA) 100-year flood zone was incorporated as a biophysical
component. The seaside neighborhood of
Brighton Beach, Brooklyn was used as a pilot area. Further review of hazard specific models is
necessary to fulfill the biophysical element of a hazard-of-place model. This
tool is intended to assist local experts, not replace them, and relies on
expert input and interpretation.
The NYCHVI reveals that the neighborhood of Brighton
Beach has moderate overall vulnerability.
While the area is economically robust, there are several vulnerable
populations present including: the elderly, the disabled, individuals
suffering from a heart condition; cancer; and/or diabetes, non English
speakers, residents of high density structures and people without access to an
automobile. In addition, several
special needs facilities are located within the FEMA 100-year flood zone
including a home for seniors, elementary school and senior day care. A hazardous waste facility also resides
within the flood zone. Over 900
residential buildings housing 4600 units lie within the flood area, as well.
Lastly, the flood zone cuts much of the neighborhood off from roadways making
evacuation by automobile impossible.
The resulting hazard vulnerability model refers to
specific place at a specific point in time.
As with any urban area, the City of New York is spatially and
temporally dynamic. Certain areas are
densely occupied by day and desolate in the evenings or on weekends (e.g.,
schools, offices). This daily
population migration should be taken into account when predicting hazard
vulnerability. In addition, some
hazards occur seasonally such as extreme heat and winter weather. The City’s built environment is a work in
progress. The thousands of demolition
and construction projects that take place at any given moment make it
difficult to obtain an up-to-date buildings layer. The data used in most of
the socioeconomic indices is from the 2000 Census. Until the 2010 Census data is made
available, estimates such as the Census 2000 Public Use Microdata Areas
(PUMAs) are an option. Certain hazards,
such as intentional chemical; radiological and biological release, are
difficult to predict using spatial hazard vulnerability tools. This hazard vulnerability assessment tool
hopes to assist local experts and its usefulness relies heavily on their input
and interpretation.
[CDC] Centers for Disease Control and Prevention and
[ATSDR] Agency for Toxic Substances and Disease Registry. 2008. The CDC/ATSDR
Public Health Vulnerability Mapping.
Noji, E.K. 1997. Chapter 8: Earthquakes. In Noji, E.K.
editor. The Public Health Consequences
of Disasters. 1st ed. New York:
Oxford University Press. p 135-178.
Very few New Yorkers reside in mobile homes (~0.07%)
thus this metric was removed. The
Economic and Race and Ethnicity group indicators were left unchanged. A
fifth group examining public health indicators was added where New York State
Department of Health, Statewide Planning and Research Cooperative System (SPARCS) data were used to determine
vulnerability based on pre existing medical conditions (i.e., heart condition,
AIDS, asthma, diabetes
and cancer). Additionally, the 90th
percentile rank (PRC90) was recalculated for the 5 groups on a city wide
(rather than a nation wide) scale. A Special Needs overlay was created to account for
facilities where particularly vulnerable populations gather including
hospitals, day care, schools, institutions and senior housing. A more complete Lifeline
overlay was added and includes infrastructure, transportation, public safety,
health care and emergency management features. These elements are symbolized using
the Homeland Security Emergency Management Symbol set. A residential
lots and buildings layer
was created using the 2006 Primary Land Use Tax Lot Output (PLUTO) data
file. Finally, a biophysical vulnerability component, FEMA’s 100-year
flood area, was added to the
layout. These overlays are used in a detail of the NYCHVI final overall
output map frame but could be added to any of the group indicator layers, as well.
Methods
The NYCHVI satisfies the socioeconomic component of a hazard of place model for the City of New York through adaptation of two of the four HVA indicator groups as well as addition of a new indicator groups and two overlay layers.
The first group,
Personal and Household,
was altered by changing
the age variable for
children seventeen years and younger to ten years and younger. The
rationale behind this alteration
stems from epidemiology literature claiming that the vulnerability of children decreases with age (Noji, 1997). Possibly,
the HVA uses seventeen as the cut
off age because some states such as Georgia and New Jersey have a minimum license age of 18 and 17 years, respectively.
New York City youth, however,
commute to school and other activities via public transit. The Housing and Transportation group required
adjustment to reflect
the nature of this large
metropolitan area.
Gretchen Culp, 05.20.2008 Lehman College, City University of New
York
EES 79904
Workshop in GISc Research
Professor Juliana Maantay