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Preliminary Flood Risk
Assessment
in Relation to
The Project
of Flood Directive
Marcin Jacewicz
Regional Board for Water Management in Gdańsk
Introduction
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EU Flood Directive – flood risk management
Conscious, planned decision making process for
the purpose of flood risk decrease
GIS – Geographic Information System – the tool
for the analysis
Flood Risk Maps
EXCIMAP (European exchange circle on flood
mapping) to elaborate guide of good practices of
flood mapping in Europe
Three Steps of Work
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Preliminary flood risk assessment maps
Flood hazard maps
Flood risk maps.
Preliminary flood risk assessment
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First step – three years
Objective – to indicate flood risk areas where
further steps will be taken
„Flood risk is the combination of the
probability of a flood event and of the
potential adverse consequences to human
health, the environment and economic
activity associated with a flood” (Flood
Directive)
Questions
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How to indicate flood risk areas?
What information do we have?
How can we collect dispersed information?
How to evaluate risk?
Who will do it?
How much time do we have?
How much it will cost?
How to indicate flood risk areas?
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Indicated areas will be further the subject of expensive
studies for hazard and then risk maps elaboration
Not indicated areas may implicate consequences of
unexpected risk and flood impact to this areas
Analysis shall consider cost and available time of
preparation (3 years)
We have to collect as much as possible of existing data
and then make a decision where the risk is high,
medium and low
What information do we have?
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Information about historical floods
Studies for flood protection
Archives
Long term prognosis
Research Projects
Information about current and future land use
Special hazards
Topography
Another dispersed data
Data sources
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Regional Boards of Water Mangement (RZGW)
Boards of Reclamation (ZMiUW)
Institutes of Meteorology and Water Management (IMGW)
Maritime Offices
Research Institutes (IBW PAN, PGI, …)
Local governments
Centra Zarządzania Kryzysowego (Prevention Management
Centers)
Fire Brigades
Citizens
Other
Conclusion
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Information is dispersed
It is not possible to manage such information
This information shall be collected within one
manageable GIS data base
One of the general objectives for the
preliminary risk assessment is to establish
unique geodatabase placing all available
flood information on the map.
How can we collect dispersed
information?
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First step is to inform and aware all stakeholders about
advantages of flood risk management and engage them to
collaboration. All shall understand their responsibility for data
sharing.
Second is to establish a tool simple to use for making it.
The information can be collected easier by using well designed
internet portal
This portal shall give opportunity for anyone, even
inexperienced, to introduce to the GIS geodatabase any flood
information by simple clicking
Data sharing have to be obligatory for main institutional
stakeholders and voluntary for another.
Historical Floods
Flood Protection Study
Data evaluation
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Then after we will have fragments of rivers and
coast lines where flood is possible.
There is a question of data reliability criteria
The source where data come from
 Data recurrence
 Data before changes
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According this criteria we can produce flood
probability
How to evaluate risk?
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Risk = probability x consequences
Consequences we can for this preliminary
assessment evaluate on the basis of the map of
land use
For example data from Corine Land Cover
Project
Land use by Corine Land Cover
The result
Who will do it?
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The idea of multi branch Project with
participation of stakeholders
Geodatabase location – Regional Boards for
Water Management
Before, kick off meetings to establish
Project definition,
 Team
 Schedule
 Budget
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No time
No money
To be continued…
Flood hazard maps
Flood risk maps