Environmental Engineering Reference
In-Depth Information
19
Flood Risk Communication
HAZEL FAULKNER, SIMON McCARTHY
AND SYLVIA TUNSTALL
Introduction
between coastal and fluvial flooding. Floods with
differing causalities have extremely varied event
timings, particularly extreme variations in event
onset, consequently requiring differing communi-
cation strategies. High tides aroundwhichflood risk
peaks at the coast can be planned for, and at least
partially anticipated in advance. In the river context,
however, variations in catchment size above the
riverine setting affects communication possibili-
ties. Small upstream catchments, where generated
discharges may be proportionately smaller,
1
expe-
rience rapid-onset floods where warnings may not
be possible. In comparison, on floodplains in the
middle and lower reaches of large river catchments,
with good radar warnings, onset can be anticipated
several hours in advance. In urban areas, rapid-onset
chaotically generated pluvial flooding allows little
in the way of anticipatory warning time. Because all
flood risk professionals are now required to address
all forms of flooding, including coastal, surface
water, groundwater and pluvially driven sewer
flooding, their new roles now demand amuchwider
range of risk communication activities beyond the
simple flood warning.
In general, flooding is a high-intensity, low-
frequency phenomenon, so that at different stages
in the 'hazard cycle'
2
(see Fig. 20.1) and over
different timescales, communication activity be-
tween professional groups and the flood-affected
public takes place in different ways. Betweenflood
events, floodplain mapping and preparedness
The changing role of risk communication in
flood risk management
It is has always been widely recognized that effec-
tive communication about flood risk is integral to
flood risk management (D. Parker, personal com-
munication). Recently, however, flood risk man-
agement (FRM) in many western countries has
gone through considerable change, expanding
beyond a focus onflooddefence toa period inwhich
a wider range of professionals and their communi-
ties will become more engaged with floodwaters
during flood events than had previously been the
case (Hall 2003). Whilst these policy changes take
time to become reality (and in fact in practicemost
flood risk in the UK is still addressed by the tradi-
tional flooddefencemethods), nevertheless there is
now a noticeable shift of emphasis away fromasset
management, towards an approach that requires
'Making Space for Water' within residential land-
scapes (Department for the Environment, Food and
Rural Affairs 2004). Thismeans that risk is increas-
ingly addressed through spatial planning and the
control of development, through 'building in'
resistance and resilience in property in flood risk
areas, as well as by encouraging enhanced resil-
ience within communities.
AsParts2to4inthisbooktestify,floodingisa
very varied phenomenon. For instance, there are
significant differences of causality and intensity
1
In England and Wales there are reported to be around 450 rapid
response rivers.
2
Referred in Chapter 20 as the 'disaster management cycle'.
