14-1190b-innovation-managing-risk-evidence

— that is, governed by random processes. Yet significant
research is devoted to produce ever more detailed models
of single elements in the ‘whole system’ (featuring, for
example, better representations of the hydrodynamic
processes, or increasingly fine-grained terrain models). The
results of such reductionist models are easily communicated,
but they fail to support risk-based choices — for although
they simulate inundation in fine detail, they are based on
gross assumptions such as the location, timing, and growth
of a breach in the relevant flood defences.
But analysts increasingly recognize the need to support
robust decisions 4 , and to do this their models must
represent all important aspects of that decision and be
truthful about the uncertainty of the evidence presented.
Here lies a bear trap. Any presentation of uncertainty is
typically viewed as ‘comprehensive’, yet it often reflects only
a few easily-described uncertainties (known unknowns).
These uncertainties may lie in the data, such as errors
in the measured height of flood defences, or in model
components such as the assessment of defence overtopping.
Although significant progress is now being made 5 , the ability
to communicate uncertainty meaningfully — in a way that
reflects data, model, and crucially model-structure errors —
remains poor.
THE INFRASTRUCTURE
PLANNER’S PERSPECTIVE
The planner of flood risk-management infrastructure
faces a significant and growing risk, but also considerable
uncertainty. Both coastal and inland flooding remain high on
the UK’s National Risk Register, with significant concerns
around the three main sources of flooding: rivers, surface
water and especially the sea. In 2012, the UK’s Climate
Change Risk Assessment identified an increase in the risk of
flooding as the greatest threat to the country from climate
change, requiring significant adaptation planning 6 .
The challenge of flooding in the United Kingdom was
also demonstrated dramatically in the winter of 2013–14,
which saw unprecedented levels of rainfall in southern
England and the largest tidal surge in 60 years. Transport
infrastructure was widely disrupted, and some agricultural
land was flooded for several weeks. Yet although some 7,000
properties were flooded, some 1.4 million properties in
England were protected by flood defences over the course
of the winter storms, and there was no loss of life as a
direct result of the December 2013 surge. The 1953 surge
of a similar magnitude killed 307 people along our east coast
and caused losses that were the equivalent of at least £1
billion in today’s money.
There have been some notable infrastructure successes.
The past 50 years have seen substantial investment in flood
risk management, with significant outlay on forecasting, flood
warning and a range of flood defences. These worked well in
2013–14, although they were tested to the extreme in many
cases, with approximately £140 million of damage caused
to our flood defences. Moreover, controversy remains a
constant theme: there were claims that agricultural land and
livelihoods were sacrificed to protect assets within urban
areas, allegedly the result of a transfer in the risk burden
from the town to the country.
Flood infrastructure planners have been innovative in the
past, and this is continuing. Improved forecasting models,
better flood warning and world-class defence systems
such as the Thames Barrier have all involved innovation
in response to risk, requiring political commitment,
time and investment 7 . As leaders on this issue, the UK’s
Department for Environment, Food and Rural Affairs and
the Environment Agency are embedding a consideration
of long-term risks in their planning, because infrastructure
investments are required to meet changing risks up to 100
years into the future. The Thames Estuary 2100 Plan is an
excellent example of such foresight 7 .
However, the improvements in defences have led to
significant developments of homes, businesses and the
infrastructure that supports them (water, electricity and
telecommunications) in flood risk areas. This in turn changes
the risk because the consequences of flooding are now
greater. Looking forward, socio-economic growth across
Europe is estimated to account for about two-thirds of the
change in risk of flooding by 2050, with the remaining onethird
coming from climate change.
Managing this changing risk requires a long-term vision
for flood risk management and the ability to respond to
changing circumstances on a shorter-term basis. It requires
us to decide what level of risk we are prepared to accept
in protecting existing properties from flooding, and the
extent to which we should veto development on flood
plains to prevent risk escalation. This demands a robust
and transparent implementation of spatial planning policy.
The government’s new ‘partnership funding’ approach
to flood defence spending also requires new forms of
local involvement in order to secure the maximum risk
reduction 8 . Meanwhile, effective risk reduction is being
greatly assisted by a continuation of the research-led
innovation that has served us so well over the past 50 years.
Coastal and inland flooding
remain high on the UK’s
National Risk Register, with
significant concerns around
the three main sources of
flooding: rivers, surface
water and especially the sea.
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