Title: Going against the flow Travel patterns in Southern France: A Vulnerability to flash floods
1Going against the flowTravel patterns in
Southern France A Vulnerability to flash floods
Isabelle RUIN ASP Post-Doc NCAR - isar_at_ucar.edu
1- Statement of research problem 2- Objectives,
study area and methods 3- Main results 4-
Conclusion and looking ahead
21- Statement of research problem
- Why people decide to travel in crisis situation?
- Two assumptions
- ? Peoples unwillingness to change their daily
routines - ? Discrepancy between individual space-time
representations and actual flash flood phenomenon
characteristics
2
32- Objectives of flash flood vulnerability
assessment
4Study area and methods
Study area
Source IGN - GEOFLA Départements Réalisation
L. Avvenengo Ducca, 2006
- Post-flood investigations (2002, 2005)
- 30 in-depth interviews
- Analysis of loss of life circumstances
- Observations during the crisis period
- Questionnaires surveys
- 960 residents (quotas)
- 260 tourists
- Cognitive mapping
- 200 residents spatially stratified sampling
53- Main resultsExternal factors
- Spatio-temporal scales of Flash Floods
- Road network exposure
- Human exposure
6Spatio-temporal scales of Flash Floods
Source Creutin, 2001
7Large road network exposure
ALES
NIMES
8Human exposure during the 2002 Flash flood event
(1)Loss of life hydrometeorological
circumstances
- 11 young individuals died in 9 watersheds
smaller than 20 km2 - 11 old individuals died in 5 watersheds bigger
than 1000 km2
9Human exposure during the 2002 Flash flood event
(2) Loss of life Warning efficiency
103- Main resultsInternal factors
- Motorists danger perceptions on daily
itineraries - Perceptions of vulnerability
- At-risk travel patterns in the Gard region
11Motorists danger perception on daily itineraries
Comparison between often flooded road sections
and risk perceptions
ALÈS
- 29 of the road sections used by our sample are
prone to flooding - The 2/3 are not considered as dangerous
Main streams East rural zone South urban
zone West rural zone North urban zone
NIMES
Road network
Source DDE30, Cognitive mapping survey, 2006. N
200 Ruin, 2007
12Perceptions of vulnerability
- Rapidity of watershed time response is mostly
underestimated, specially for small catchments - More than 60 ignore that 2 feet of moving water
may sweep a car away while critical water depth
for a person (to be knocked off their feet) is
better evaluated - Only 35 of the residents think Météo-France
Orange alert is to a warning for fatal danger,
but 55 associate it with danger on their own
daily itinerary
- Traveling during a flash flood event is known to
be dangerous, but thresholds of dangerousness are
hardly perceived
13Three kinds of at-risk mobility in the Gard area
ALÈS
NIMES
Source DDE30, Cognitive mapping survey, 2006. N
200 Ruin, 2007
143- Main resultsContextual factors
- Influence of spatial and settings
- Main constraints to evacuation
- Main constraints to travels flexibility
15Influence of spatial and temporal settings
- Stakes located at the confluence of watersheds of
different sizes - Succession or simultaneity of flood peaks due to
differences in catchment sizes - Vulnerability variations within the time of the
day, week, season...
16
16Main constraints to evacuation
- Afraid of spreading the family 37 tourists
- Feeling of safety 27 residents
- Afraid of leaving pets 18 residents
Afraid of spreading the family
17Main constraints to travels flexibility
- In reaction to warnings, 50 of the parents
would pick up their children from school.
- Workers would hardly cancel their travels
184- Conclusion and looking ahead
- Complementarity of qualitative and quantitive
methods in behavioral studies - Synthesis of vulnerability factors in crisis
period - Research perspectives
19Complementarity of qualitative and quantitive
methods in behavioral studies
20Synthesis of vulnerability factors in crisis
period
21Research perspectives (1)
- Need for Behavioral verification surveys to
assess adaptative capacities of drivers in
different weather conditions
- Observe behaviors in both normal daily life and
extreme weather conditions - Organize extreme events post investigations
22Research perspectives (2) Behavioral survey
project NCAR ASP proposal (2008-2009)
- Observe drivers behavior at low water crossings
in Texas (Austin)
- Quantitative survey
- Use of video, car counting
- Qualitative survey
- Use Youtube video, travels log and in-depth
interviews
23Research perspectives (3) DELUGE network E.
Gruntfest submitted NSF proposal (2008-2013)
2. Disasters Evolving Lessons Using Global
Experience
- Focus on post-event field studies for floods to
maximize interactions between social scientists,
hydrologists and meteorologists - New guidelines on post-event investigations for
use by integrated teams of physical scientists,
social scientists, and practitioners.
24Thank you