2. Why care about urban resilience?
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3. Setting the context: how do we define urban?
26/03/2015 Copyright 2015 Opticits Ingenieria Urbana S.L. Proprietary and Confidential 3
Not a universal definition for a city but some common features
(demographic/ functional perspective):
Permanence
Large population size
High density
Social heterogeneity
Mix of activities: trade, services are predominant
Core centers of economic and wealth production in a country,
as well as of high level education
High connectedness level (city level but also within the country
and beyond)
Cities generally have advanced systems (compared to rural
areas) for sanitation, utilities, land use, housing, transportation,
information and communication (infrastructure in general).
Urban areas represent areas under direct influence of one (or
more) city(ies) – terminology will also differ significantly from place
to place. Peri-urban areas cover areas ensuring the continuum
between urban and rural areas.
From a resilience perspective, as will be developed in this course,
those specific features are core factors of risks (and opportunities)
to consider.
A definition for
OECD cities?
The OECD and the
European
Commission
developed a new
definition of a city
and its
commuting zone in
2011, to improve
he comparability,
and thus also the
credibility, of cross-
country
analysis of cities.
See Redefining
urban: a new
way to measure
metropolitan areas
(OECD 2012,
http://www.oecd.or
g/regional/redefinin
gurbananewwayto
measuremetropolit
anareas.htm )
4. Cities are yet at risk …
Cities have always faced risks over time, facing resource
shortages, natural hazards, and conflicts of varying kinds.
Key features of urban areas as previously introduced make
them particularly vulnerable to potential risks – entailing highly
impacting damages (see NY illustration), e.g.:
Large population size: magnitude of human consequences
for a given event
High density: concentration of population and assets
exposed to potential events
Mix of activities (trade, services are predominant):
dependency on external natural resources and on
distribution networks for critical services (e.g. water, food,
energy)
Core centers of economic and wealth production in a
country & high connectedness level : potential cascading
effects at city scale and beyond (a crisis in a major city can
impact the local and even the national economy)
Characteristics of urban areas provide also a whole range
of opportunities for risks management as will be discussed
later.
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The Katrina disaster in 2005
crystallized a key moment of
the paradigm shift in the
epistemological approach
and the consideration of
urban risks (Diab, 2013 a,b).
It showed that urban
resilience is not just the
ability to find a new
equilibrium in the wake of a
disruptive event, that is to
say, a state of a certain
functional and temporal
stability. It expresses, in
particular, the potential of
urban systems to renew and
to reorganize by correcting
past planning and
engineering mistakes and
especially to prevent any
new disaster. In the case of
Katrina, this required fresh
scrutiny of dike maintenance,
ageing protection structures,
informal or poorly thought out
urban planning and the lack
of human and technical
resources within local
authorities, etc.
