Participatory and Collaborative
Digital Mapping to Enhance
Community Disaster Resilience

The Demand
• The Sendai Framework for Disaster Risk Reduction
Theme 1 -
Understanding Risk needs … “to develop, periodically
update and disseminate, as appropriate, location-
based disaster risk information, including risk maps,
to decision makers, the general public and
communities at risk of exposure to disaster in an
appropriate format by using, as applicable, geospatial
information technology”.

The Problem
• Data deficiency in developing countries

The Problem
• Global Model VS Local Need
“Global Flood Risk Models have their
limits compared with local-scale models,
and there is often a mismatch between
their actual ability and the envisaged use
by practitioners. … without profoundly
improved representations of exposure
and vulnerability, gains from improved
hazard modelling will not filter through
to improved risk estimates.”
Ward, et al. (2015). Usefulness and limitations of global flood risk models.
Nature Climate. Change

Old Data – Participatory Mapping
Participatory Rural Appraisal (PRA) and
Vulnerability and Capacity Assessment (VCA)
• Resource map
• Social map
• Risk map

Evolution of Participatory Mapping
• Ground mapping
• Sketch mapping
• Transect mapping
• Scale mapping
• 3D-modeling
• GPS mapping
• Aerial/Remote sensing imageries
• Multimedia mapping
• PGIS

An Integrated Approach
The general procedure –
a) Collect and digitize or rasterize existing analog community
maps (PRA, VCA and others) and identify geographic
locations of target communities;
b) Conduct remote mapping on the OSM platform using both
satellite images and community maps and generate
preliminary baseline community maps;
c) Develop, together with local stakeholders, field surveys to
fill major data gaps in the preliminary maps;
d) d) Organize focus groups with local communities to
discuss and further improve the baseline maps;

The general procedure (continued)
e) Maintain traditional community participatory mapping
activities using baseline maps as the basis and add
information to capture new changes (e.g., land use changes,
impacts from recent disaster events) and discuss risk
reduction and preparedness options;
f) Store spatial information locally in a GIS (likely by
government agencies and NGOs) and upload non-sensitive
data to OSM;
g) Periodically update the maps and share and exchange
them across communities and with regional stakeholders.

Pilot – Karnali River Basin, Nepal

2014 Flood in Karnali River Basin

Pilot in Lower
Karnali
[2015-2017]

Results – Lower Karnali River
Basin
50,000 + buildings and 100+ km of roads
mapped in half a year

• Overlaying the available flood
inundation maps over Open Street
Map layers for Lower Karnali
Region
• Making comparison between the
model outputs from HECRAS and
Delft 3D Modelling for 20 Year and
100 Year Flood Scenarios
• Also looking how the inundation
map for modified river section (way
to incorporate sediment dynamics)
differs in extent and exposure
Scale up in Lower Karnali River basin

•Extent:
•Delft 3D modelling
captures larger extent
of lower depth
inundation
•Hot spot zones:
•Northernmost delta
region-Delft 3D Model
•Southernmost delta
region-HECRAS
•Southern border
region of Tikapur for
both models

• Similar differences
across the model
results as observed
for 20 year flood
scenarios
• Level of flooding
increased in the
hotspot zones
• Delft 3D Modelling
captured more
prominent flooding
beyond the Nepal
border

0
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0-0.5 0.5-1 1-1.5 1.5-2 2-2.5 2.5-3 3-3.5 3.5-4 >4
NumberofBuildingsExposed
Flood Inundation Depth (m)
Karnali Flood of 20 Year Return Period
Exposure Details Vs Inundation Depth
Delft 3D Modelling using
TanDEM-X
Delft 3D Modelling using
TanDEM-X (River Section
Modified)
HECRAS Modelling using
SRTM DEM
0
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10000
15000
20000
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0-0.5 0.5-1 1-1.5 1.5-2 2-2.5 2.5-3 3-3.5 3.5-4 >4
NumberofBuildingsExposed
Flood Inundation Depth (m)
Karnali Flood of 100 Year Return Period
Exposure Details Vs Inundation Depth
Delft 3D Modelling using
TanDEM-X
HECRAS Modelling using
SRTM-DEM
Preliminary Flood Risk Analysis –
Inundation Depth Vs Exposure Building Details

Disaster Resilience Building
• Improve human and social capital directly
• Building new relationships among local
stakeholders
• An inclusive partnership
• Support better land use planning and
management of natural and physical capital

GPDRR Award
Youth-led
Projects on Flood