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Contribution of citizen science in
flood hazard assessmentBocar Sy, Corine Frischknecht, Hy Dao, David Consuegra, Gregory Giuliani
Yeumbeul Nord:
Area: 9km2
Total population: 168’379
Altitude: 0-20m
Several floods: 2005, 2009
Flooding causes: Natural and
anthropogenic
Where: Yeumbeul Nord, Dakar, Senegal
Dakar
Sea
This area is characterized:
Lack of catalogue of past
events
Poor coverage of
hydrometeorological data
No regular update of basic
data
Some issues with satellite
images (e.g frequency)
82 Neighbourhood
chiefs and 182
local
representatives
Local associations
and selected
people
Local associations
Training, rain
gauge fabrication,
data collection,
data on Facebook
Validation of land-
use map, mapping
with handled GPS
and mobile GIS
Training on map,
mapping on the
field, double
checking
Rainfall data acquisition, land-use mapping and investigation on
past flood events
Training, different target
groups, local languageHigher
quality data
Rainfall Land-use Flood events
daily
average
information
more detailed
and updated
depth
extent
How: Involvment of citizens
Daily average rainfall
0
5
10
15
20
25
30
35
40
45
TND DRS5 LDIAT NSEN MSY DBA Dakar Yoff
30.08.2016 06.09.2016 10.09.2016 11.09.2016 17.09.2016
Citizen rainfall data versus the nearest official station
(Dakar-Yoff), located 20 km from Yeumbeul Nord
Official station
.
Citizen gauges vs official station
Values are in the same range
with a variability less than 10 mm
(exception of 17Sept.)
Results
Extent
Neighbourhood chiefs vs
remote sensing
Some differences in spatial
distribution
Remote sensing 0.72 km2 and
neighbourhood chiefs 0.90 km2
an increase of 25%
Neighbourhood chiefs
2009 event: depth varies from
0.2 m to 1m
Depth
Results
Citizenscience
Ground
dataCitizenscience
Scenario
Basic
data
Key flood
hazard
parameters
Scenario
Basic
data
Key flood
hazard
parameters
Past flood events
having affected the
area
Land-use elements
potentially influencing
flood magnitude
Rainfall intensity
An alternative approach
for areas with scarce data
and insufficient financial
resources
New insights on
Thanks