Environmental Engineering Reference
In-Depth Information
One solution is to incorporate local knowledge
more fully, to enhance and validate the maps.
Pappenburger et al. (2005) explored the wider
range of tools that is available for the articulation
of both future flood risk and uncertainty by hy-
drologists, oceanographers and meteorologists in
real-time situations. Their optimization for differ-
ing professional challenges in FRM was explored
by Faulkner et al. (2007). In the more constrained
context of a real event, however, FRM profes-
sionals rely much more on the radar/rainfall
ensemble interface, and it is here that the role of
uncertainty tools has seen the most progress. 3
These tools and their application are discussed
in much more detail in previous chapters (see
Chapters 7-9 and 14).
Flood science underpinning planning
and in warnings
Traditionally, then, H t is the central component of
the traditional formulation of risk, R t , and in
floodplain settings above is described by a dis-
charge frequency curve derived from a long-term
hydrological record. The consequences part can be
assessed for individual hazard events by using the
peak discharges as modelled with the aforemen-
tioned physical models, to give assessments of
floodplain inundation for that event, which can
then be costed for damage using depth-damage
curves to give an economic estimate of the con-
sequences of such an event (Penning-Rowsell
et al. 2005). Integration over the cumulative
distribution of events provides an estimate of
total risk, S
R t , at a particular location. Whilst
there is not sufficient scope here to review the
vulnerability literature, increasingly other mea-
sures of vulnerability can also be used, for example
measures of societal vulnerability. Thus total
risk, S
Intra-Professional Flood Risk
Communication
Quite apart from the translation of scientific for-
mulations of risk as a means for communication
tool development, professionals frequently com-
municate between themselves. As part of the
activities in the first phase of the Flood Risk
Management Resesarch Consortium (FRMRC),
the Flood Hazard Research Centre at Middlesex
University (FHRC) undertook case-study research
on the professional risk communications occur-
ring in two professional settings: spatial planning
and development control, and in the warnings
field in the UK (McCarthy et al. 2008).
We looked specifically at flood maps and warn-
ings as flood risk communication tools. The
research explored the constraining effects on their
incorporation into risk communication strategies
of (i) the differing professional settings, and
(ii) differing flooding contexts represented by three
case study areas. The differing flood types we
studied were described as 'simple' (slow onset,
predictable floodplain flooding such as occurs in
the mid-Trent basin in the UK);
R t, is sensitive to both spatial and temporal
variations in both H and V. Total risk calculated
this way can be mapped, and used to define
zonation bands for use in prioritization and
decision-making, especially in a floodplain context
(e.g. the high, medium and low flood risk zones
used by professional planners). Additionally, the
static 1:100 maps etc. can be replaced in the
risk assessment by real-time one-dimensional
(1D)/two-dimensional (2D) simulations to assist
decision-making (as discussed in Chapters 12 and
13 of this topic).
This classical formulation of risk as the product
of the probability of an event and the conse-
quences of that event is still widely used, despite
arguments that the stationarity of the temporal
series (and therefore its potential to be extrapolat-
ed into the future) has to be questioned in the
context of climate change predictions. However,
in the sense that both H and V are estimates, there
are considerable uncertainties embedded in the
EA flood risk maps available for the 1:100 and
1:1000 events - it is an inconvenient truth that
flood hazardmaps are as certain as themodels used
to generate them (see debate in Lavis et al. 2003).
'complex'
3
Because these tools are extensively outlined in other parts of
this topic, readers are referred to other chapters for the details of
these approaches.
Search WWH ::




Custom Search