It was concluded
that the methodological framework helps structuring and integrating the
information in support of flood event decisions. However the end user
responses show that this framework has no added value to them.
This
research started with the aim of risk-based decision making for flood
event management. In the context of flood risk management in general
and particularly as defined in the FLOODsite language of risk, risk
metrics are defined as a combined measure of probability and
consequence. This leads to an average number of euros per year or
expected number of affected persons. The three pilot applications
showed that these kind of risk numbers are not suitable for evacuation
and traffic management. The ‘risk estimates’ as proposed in both
FLINTOF and the ESS are more general defined and comprise flood
extents, number of casualties, potential building collapse and
evacuation times.
The methodological framework was applied in three
pilots. The three pilot applications did not cover the whole scope of
the this framework, but focused on specific aspects defined by the
different end users. Two prototype DSSs, FLINTOF and ESS, were built
for the Thames and the Schelde pilot respectively. The DSSs are
country-specific, i.e. adjusted to the countries’ models and commonly
used methods. The DSSs address different end-users that have different
responsibilities and information requirements. Because of this, the
DSSs were implemented as different software tools. The ESS provides
assistance on making evacuation plans before the actual flood event,
while FLINTOF also provides information on emergency access during a
flood. In addition, FLINTOF requires a higher level of technical
expertise of the end user, compared to the ESS.
Despite these differences, we found that the resulting prototype DSSs
have more in common than expected beforehand. Both systems show risk
maps for different flood scenarios and support evacuation planning by
showing the effect of management response options to reduce the impact
of flooding. This means a combined technological framework for both
DSSs might have been successful. Whether different implementations of a
DSS for FEM are needed thus depends on the type of natural system more
than on the type of end-user.
In the French pilot the input from detailed 2D modelling to the
requirements of emergency planning in urban areas was studied. The
central part of the framework was applied to show how hazard maps,
vulnerability maps and risk maps can be used to plan activities that
reduce the impact of flooding. Not only can these be maps be used to
plan evacuation routes, but also for related city planning such as safe
locations of parking areas and water supply systems, and designation of
safe exit points of hospitals and schools.
The products of
this research are most relevant for the implementation of the Floods
Directive (Directive, 2007). Tools have been provided to plan flood
event management (flood risk management in the very short term). By
making use of hydrodynamic model results and available data on area
vulnerability, the preparation of flood event management plans is
supported. Also evacuation routes and best locations for shelters can
be derived from this information. Together with evacuation and rescue
planning, this will most likely reduce the adverse consequences of
floods.
The principal benefit of the urban flood modelling lies in the
integration of the appropriate sources of information for preparing
emergency plans in France. The results are detailed and can therefore
be readily used in the preparation of community safeguard plans.
The
authors of this research have tried to involve the end users, by paying
attention to their requirements and by asking them feed back on the
preliminary prototype DSSs and the preliminary results obtained during
the research. Their comments and suggestions were included in the final
prototype DSSs, of which a guided tour can be found on the CD ROM,
enclosed with the full report.
The following is
recommended regarding the flood event management DSSs:
- The prototypes should be developed
further and implemented, using real and complete data, in close
cooperation with the end users in order to learn more about their
practical applicability;
- A dynamic link with evacuation models
should be incorporated, allowing for interactive event planning by the
end user;
- DSSs should be used to create real life
evacuation plans in the form of a test case. This will show the
usefulness of the DSSs and will allow identification of issues for
further development.
- A simple exchange should be made possible
between the information in the Schelde DSS and FLIWAS, a DSSs under
construction that focus on communications and responsibilities in flood
event management;
- DSSs for evacuation and rescue planning
would have to be secured to ensure privacy of information and would
only be available to selected emergency responders’ sites;
- In the future the DSSs might be operated
on a real time basis that would allow the water management
organisations to update the emergency services of the flood risk as
flood forecasting information becomes available, i.e. rather than just
forecasting floodwater levels it would be possible to forecast the
flood risk and prioritise the response to the flood based on the
forecast results. This also allows coupling with dike breach forecasts
from a realtime embankment monitoring systems, such as currently being
developed by Deltares (www.Deltares.nl);
- Flood event scenario based DSSs offer a
unique training environment for both decision-makers and intervention
forces.
The following
recommendations can be deduced from the work on inundation modelling
for flood event management in urban areas:
- Buildings are currently modelled as solid
objects, while in reality the water may flow through windows and doors
and each of the objects represents a storage capacity, which is
disregarded now;
- The effects of interaction with the sewer
system and groundwater should be included in the modelling approach.
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