Memorandum submitted by Professor Donald
Knight (FL 85)
Comments on the recent floods (Summer,
2007)
1. INTRODUCTION
We have been here before—Thames (1947),
Lynmouth (1952), Severn (1990), Leamington (1988), UK wide (2000),
Boscastle (2004), Carlisle (2005) and today (2007). And that ignores
all the coastal flooding events in the UK and numerous events
overseas. So it's not new. I offer here a few comments on issues
that you will not often hear about via the media, but which are
drawn from my personal experience of working on certain aspects
floods for many years. I will avoid detailed technical issues,
which of course I can explain, but references are provided for
those interested in such matters.
I would remind you that however distressing
the consequences of flooding are here in the UK, our problems
are mild compared with those in other countries (e.g. Bangladesh,
China, USA, Mozambique, etc.). Of all the natural catastrophes
that can occur (earthquakes, storm, flood, etc.), floods are still
the biggest killer in the world, especially so in Asia. However,
even in the developed world, and notably in Europe, we have seen
devastating floods in the last decade, some in part due to climate
change. The articles on "Floods—are we prepared"
(Knight et al., 2006) and "Examples of recent floods
in Europe" (Knight & Samuels, 2007) illustrate this.
The journal in which these two papers appear (see references)
indicates how much more prepared the Japanese are in their forward
thinking about policy and practice for all types of disaster,
in funding R&D institutes and in public awareness campaigns.
So as far as the UK is concerned I suggest you
look back at the ICE presidential commission report "Learning
to live with rivers" (November, 2001), which reviewed
the technical aspects of flood risk management in England and
Wales, following the widespread flooding in Autumn 2000, the wettest
Autumn period in the UK for 270 years. The report was later published
as a book, under the title of "Flood risk management"
(Fleming, 2001). More recently, I had the opportunity to bring
together many European experts and researchers to run an Advanced
Study Courses for the European Commission of flooding issues.
The series of lectures were later published as a 607 page book
in 2006, under the title "River basin modelling for flood
risk mitigation" (Knight & Shamseldin, 2006). So,
as I say, it's not new, and is familiar territory for river engineers
like myself and other professional colleagues. If you read our
conclusions in the ICE 2001 report you will find many aspects
that are as relevant today as they were then, and indeed, many
recommendations that have still not been addressed. Having said
that, the recent rainfall in June and July this year has been
exceptionally severe.
2. GOVERNMENT
I do not wish to be unduly critical, but as
an academic it is my job to offer advice and comment, especially
on technical issues within my province. I leave it to the politicians
to act or not—it is their prerogative. So I begin with two
comments on the role of government and the part played by the
Department for Environment, Food and Rural Affairs (defra), as
that government department controls the Environment Agency (EA),
sets policy and is therefore important.
(i) It is inexcusable that a few years ago
defra abolished the post of Chief Engineer. We have a very able
chief scientist to the government, Sir David King, who led the
Foresight programme (2003) on flooding. But however good that
programme was, it was looking at long-term issues and hence not
particularly focused on the "here and now" practical
issues. I suggest we must have engineers in charge of technical
issues related to engineering. The last chief engineer at Defra,
Reg Purnell, was an outstanding leader whose expertise and political
acumen we miss. We see how inter-related many flood issues are—affecting
infrastructure, water supply, power generation and transport.
Floods are pre-eminently about the built environment, which Civil
Engineers have all the necessary expertise to deal with. Engineers
use the best science available, but add to that their own experience
of what has been done in the past and the art of the possible.
Within Government, it is astonishing that we have chief scientists
for food safety, veterinary practice, pharmacy, science, etc.
but not one for "engineering". Perhaps this is why successive
UK governments have been so timid and lacklustre about major engineering
projects—high speed rail links, nuclear energy, tidal barrage
on Severn estuary, etc., to name but a few.
(ii) The lack of adequate funding to do
the job properly in a changing environment is another clear failure
of government. Having been an advisor on fluvial processes to
defra for 6 years (1999-2005), one always expects to see some
proposals ignored, advice not taken and written reports collect
dust, but to have the majority suffer that fate is frustrating.
At the final plenary meeting of all the Theme Advisory Group (TAG)
members in July 2005, there was considerable disquiet at the lack
of investment in both R&D on flood risk management and at
the projected expenditure levels on the constructions and maintenance
of capital flood defences. A figure of at least £1 billion
was suggested for the latter. Although expenditure on capital
works has increased from around £300 million to £500
million over a decade, and Hilary Benn has this week announced
a further increase to maybe around £700 million, it is still
not enough. These large sums need to be set in the context of
the £2.5 billion cost to insurers in these last two months
alone, and the value of national infrastructure assets at risk
from flooding in the UK, estimated to be of the order of £300
billion. It was deplorable that in 2006 defra actually reduced
expenditure by £15 million on the vital modelling work done
by engineering framework consultants on flood risk planning, in
order to meet a shortfall of cash arising from the needs of the
farming community, due to defra's own poor administration and
lack of foresight. The lack of funding, both for the maintenance
of capital works, R&D and strategic consultancy work must
be laid at the government, not the EA, but this is not to say
that the EA has no shortcomings.
3. THE ENVIRONMENT
AGENCY (EA)
(i) I suggest the EA has some serious strategic
weaknesses in its management and policy. Despite perpetual re-organization,
the EA is a top-heavy organization with a poor science base, especially
to do with the hydrodynamics of rivers and floodplain processes.
(ii) Furthermore, it made a major error
in the late 1990s by out-sourcing all its hydrodynamic modelling
expertise to consulting engineers, referred to as the "framework
consultants". Although it is sensible to have a team of experts
outside the agency, tied in for the long-term rather than for
ad-hoc consultancies for particular schemes, never-the-less it
is inappropriate for the EA to have no effective internal expertise
left at all. In 2001 we debated about whether the management of
flooding within the UK should be taken away from the EA and given
instead to the Met Office, mainly on the grounds that the latter
has a better science base and also on the grounds that this might
bring meteorological, hydrological and hydrodynamic modelling
together, which in some cases is desirable. We decided not to
recommend this, but it is noticeable that the EA is hardly visible
at scientific meetings or via publications in learned society
journals. It is hardly ever present at international conferences
presenting the results of hydrodynamic model results, which are
at the heart of flood risk mapping and management. It has disbanded
all its modelling teams and lost most, if not all, of its expertise
in this strategic area.
(iii) This brings me to a third comment
about the EA. It is water level that is of crucial significance
in flooding, albeit driven by discharge via precipitation. The
prediction of the stage-discharge relationship is not necessarily
as straightforward as most people expect (see references). Some
theoretical aspects related to estimating the H v Q relationships
for overbank flows and extreme flood events are complex. Consequently
much of the data collected by the EA for high flows at gauging
stations that are outflanked or inadequately designed is surprisingly
high. Consequently, the Flood Estimation Handbook (FEH), and later
revised derivatives, contains spurious data on which return periods
are estimated. In addition, most mathematical models require good
quality data (not just HvQ) for calibration purposes. Nearly every
single project I have ever been involved with for the framework
consultants over many years indicated some sort of errors in gauging
station data. Unless the EA uses models intimately, it never understands
fully the poor quality of much of their own data, the poor spatial
and temporal coverage, and the inadequacy of it for really developing
mathematical models to a higher level. Too many flood risk maps,
derived from such models, are inadequately calibrated and are
of poor quality. For the last two Summers, supervising MSc students
working separately for Halcrow and Peter Brett Associates (pba)
problems with data became glaringly obvious yet again.
The FEH was sponsored by one particular Research
Council (NERC), without any reference to other Research Councils,
such as EPSRC, and regrettably it is therefore completely biased
towards hydrology and omits any consideration of hydraulics or
hydrodynamics. These did at least get a brief mention in the original
Flood Studies Report in the 1970s, a forerunner of the FEH. This
bias in the FEH has had the effect that in flood analysis, there
is an undue focus on only one half of the problem, discharge and
not water level. It is now time that the EA/defra put all its
hydrometric water level data onto a single CD, so that for any
UK river in any catchment the water level data is systematically
given to Ordnance datum along a river course. Explanatory notes
should be given for every gauging station, together with complete
hydraulic equations, allowing sensible extrapolation to be undertaken
where necessary. Historic flood data could also be added, as well
as flood outlines for particular frequencies of precipitation
or run-off. This would mirror perhaps how catchment descriptors
are available for all UK catchments within FEH. The idea of a
Flood Plain Handbook (FPH), as a companion to the FEH, is one
close to my heart. Further work is also desirable on the UK Roughness
Advisor (RA) within the Conveyance Estimation System (CES), as
it is crucial for accurate hydrodynamic modelling. Indeed I have
proposed these things several times, and again more recently,
as highlighted next.
(iv) Fourthly, the EA is under statutory
control to develop and operate a hydrometric scheme for rivers
in England and Wales. This largely consists of rainfall and river
flow (or water level) gauges at various points in a catchment.
Long term records are kept and used for frequency analysis, producing
key statistics, flow duration curves, etc. Although the EA does
some excellent work in this respect, it is starved of funds, does
not treat its hydrometric division with the status it deserves,
and has divorced many of its monitoring teams from the end-users,
thus denying them the opportunity of seeing how their data are
crucial in flood risk management. For example, if the EA possessed
more capability in modelling, the inadequacies of simply regressing
equations through data, without any real understanding of the
physical processes that produce that data would become apparent.
Weir formulae are seemingly disregarded, inbank and overbank rating
curves are often established with no hydraulic vision, so cannot
be safely extrapolated, etc. Imaginative ways of measuring new
kinds of data are also not encouraged enough. A fundamental reform
of our hydrometric scheme and the use to which data are put is
long overdue. More imaginative ideas on measuring water surface
slope, resistance coefficients, surface velocities, video cameras
at many more stations might help. I have recently put such a proposal
up to the EA, but have had no response. Is this because "management"
is devoid of technically perceptive enough engineers to see the
significance and adequate funding for this type of work? I wrote
the section in the ICE report (2001) on "the intelligent
client", ie the EA, which should be re-read, as well as helping
to get the EA "skills shortage" working group (2004-06)
off the ground. I am also currently involved in a 3 year EPSRC
sponsored research project titled, "New approaches to
estimating flood flows via surface videography and 2D & 3D
modelling", run jointly between Birmingham and Loughborough
Universities, the Centre for Ecology & Hydrology at Wallingford
and a Japanese University.
(v) Fifthly climate change. Defra and the
EA have suggested the adoption of a precautionary rule that adds
20% to river flood flows to account for climate change up to 2115.
Two recent studies by MSc students at the University of Birmingham
(Bearne, 2006 and Green 2007) have shown that the basis of this
rule is intellectually flawed and in practice is an underestimate,
especially for urban or impermeable catchments. See Table B2,
page 16, of PPS25. Comparisons were made on three UK catchments,
sponsored by two leading framework consultants (Halcrow and pba)
who were sceptical of the EA's advice and wanted to see for themselves
how it applied in practice. One has to ask why it is that the
question of the validity of this rule is first raised by two students
writing their MSc dissertations. Why is the science group in the
EA not engaged in such work? Again it points to lack of strategic
thinking, modelling capability and awareness.
(vi) Building on floodplains. In reports
like "Making space for water", in planning guidance
notes (PG25) and in planning policy statements (PPS25), consideration
is given to development on floodplains. Water needs to be either
stored of conveyed down a river course and in times of flood it
soon becomes apparent how buildings and infrastructure on floodplains
limit the flow and heighten water levels. Compound channels are
a useful way of maintaining ecological status and also providing
extra discharge capacity when needed in times of flood. These
types of channel are popular in Japan, and have been researched
in the UK (eg Flood Channel Facility work at HRWallingford. See
www.flowdata.bham.ac.uk). Never allowing any construction on some
existing floodplains is not tenable (eg London), but serious consideration
needs to be given to controlling developers better, as well as
government house building programmes (eg Thames gateway). Various
examples exist in the UK of how the EA's advice has been overridden
by central government with regard to allowing unsuitable development
of buildings. If strict power regarding planning approval is to
be devolved to the EA with regard to flooding, then their modelling
expertise will have to be taken to the highest level in order
to produce flood risk maps that are demonstrably accurate and
will not be disputed by other hydrodynamic experts in a court
of law. This reinforces the points previously made about improving
river and floodplain modelling within the EA.
(vii) My last comment on the EA is one that
possibly illustrates the lack of hydraulics knowledge. In my last
letter to Reg Purnell (27/07/05), I set out 5 issues that I thought
were important concerning the new R&D arrangements. Regarding
one issue I said "As you are aware, I am still somewhat concerned
about the capability of some of the senior management within the
Environment Agency in this respect, particularly when dealing
with technical fluid flow issues. You have to look no further
than the Jubilee channel as a monument to the "skills shortage"
within the EA. A new £90 million channel takes only 2/3 of
its design flow—how basic can you get? Especially when the
EA has a new "Conveyance Estimation System", developed
through a £0.5 million R&D managed programme, and then
"launched" in June 2004. But it gets even worse, as,
in another criticism of the EA, I have to say that the CES software
is still not available to anybody within the Agency or by consultants
who want it, due to EA "procedures'".
And in a postscript, I have to add that it is
still not available today, even in July 2007! This just reinforces
my view that dealing with the EA is a bureaucratic nightmare.
You just have to talk to any consultant and they will say the
same thing. Baroness Young and Sir John Harman are both culpable
in this respect and need to seriously consider their functional
capabilities. The group may wish to see the whole of my letter
of 27/07/05, and Reg Purnell's response, since they both deal
with the important issue of R&D within defra and the ERA.
I was co-author of the 2005 report "A vision concerning the
hydraulics knowledge base required in river engineering and associated
research needs" (Knight & Ramsbottom, 2005), for the
Defra/Environment Agency Flood and Coastal Defence R&D programme.
4. PRIVATE AND
PUBLIC UTILITIES
It is now widely recognized that flooding is
not just pluvial or fluvial, but may be caused by poor drainage
and infrastructure in inappropriate places. Thus the private sector
needs to be involved, as do local government. Consideration needs
to be urgently given to policy and planning regulations regarding
the various parties (water and sewerage companies, like Severn-Trent),
as well as the difficult technical issues related to combined
surface and sub-surface modelling of water flows. Many planners
and developers seem to have lost sight of certain simple principles
regarding water. Some aspects of drainage are not rocket science,
even though complex modelling via Infoworks and other software
packages is. On this issue, the UK is in danger of not supporting
software development enough at centres like HRWallingford, or
in consultants and universities, where much work is done, but
not at a commercial level. The private sector alone cannot support
continual development of software for river engineering as it
is not cost-effective in their terms. An example of this is the
well respected ISIS software, now used extensively throughout
the UK for flood risk mapping by the framework consultants for
the EA. It was mainly developed in the private sector on a very
limited budget, eked out of profits from commercial consultancies,
and with little support from central government or the EA. We
could be a world leader in such software, but our position is
weakening, with other countries developing their own systems.
The excellent work done by UK engineers, especially at HRWallingford,
is shown by their leadership of the largest European collaborative
R&D project known as Floodsite (website below). Our research
establishments, and particularly our university laboratories,
need more funding from central government, otherwise the UK will
lose out further in terms of world markets and influence in this
important area.
5. HOME OWNERS
The EA is not an emergency service, and the
fire service and police are not paid to solve flooding problems.
Home owners must not expect the government to do everything. Home
owners need to take responsibility themselves, consult flood risk
maps and when exchanging property ensure that solicitors understand
the significance of these maps. They should consider basic drainage
concepts in relation to their property, as well as PPS25, as insurance
companies certainly will. The tacit "gentleman's agreement"
between the UK government and the insurance companies is just
about at breaking point. The UK is the only country in Europe
where flood insurance is still possible to obtain. The insurance
companies only agree to insure properties in the UK on the assumption
that the central government puts in sufficient resources to protect
against flooding. Hence the importance of the £500 million
highlighted in Section 2(ii) and defra's need to increase this
to where the TAG groups think it should be. Developers building
on floodplains need strict control, without trivializing planning
as is the danger in some of the requirements in PPS25. Projects
involving the Thames Gateway scheme and the future of the Thames
barrier involve some complex and politically difficult issues.
6. THE MEDIA
The media love floods, but regrettably for most
of the wrong reasons. They like dramatic pictures, disaster video
footage but give little analysis. The UK has some excellent research
scientists and engineers, and has done some sterling work. Sadly,
the scientists get more coverage than the engineers. This is one
reason why a Chief Engineer should be at the heart of government
to give authoritative leadership on major engineering issues.
The media rarely comment on the EU Water Framework Directive,
(2000) and the more recent EU Flooding Directive (2007), both
of which will impinge on legal and policy issues for many years
to come. Instead the media seem to like climate change issues
more, which happily does at least relate to floods. As a result,
the public has improved its understanding of climate issues, even
if governments have been more cautious in their actions. The media
needs to understand the concept of a return period in a non-stationary
time series and the concept of adaptive flood risk management.
In the same way, defra and the EA need to work to higher levels
of flood defence, possibly taking 1 in 200 return periods and
beyond as the norm, as well as contemplating and designing for
those situations when flood defences are overwhelmed.
IN SUMMARY
1. Government—no Chief Engineer; lack
of funding for R&D, capital works, maintenance & operational
activity regarding flood schemes; policies on floodplain development
are re-active rather than pro-active with respect to floods; research
needed on the 20% rule in PPS25; needs to develop adaptive flood
risk management policies and consider worst case scenarios; avoid
the "complacency" cycle.
2. Environment Agency—lack of strategic
management at technical level; poor science base with regard to
river hydrodynamics; should not necessarily stop out-sourcing
of modelling, but should develop internal modelling capability
as well; should improve hydrometry and application of new technology,
including remote sensing; consider worst case scenarios; should
develop a Flood Plain Handbook (FPH) on water level data for the
UK, somewhat akin to the Flood Estimation Handbook (FEH) and CDrom;
develop the Roughness Advisor with suitable water surface slope
data.
3. Private & public utilities—better
co-ordination of flood risk management policies with defra and
EAa is needed; financial penalties and inducements are needed.
4. Home owners—consult flood risk maps;
use flood proofing if necessary, it is their responsibility; think
about the unthinkable and how floods might affect their property.
5. The media—not very reliable and
always focusing on the dramatic, visual material; media needs
to be more informative and highlight the complex engineering issues
involved; engineers maybe need to learn to be more media savvy.
6. Final comments—"learning to
live with rivers"—are we? Perhaps we are not learning
fast enough and making sufficient "space for water"?
There are many websites related to flooding issues (try a few
key words in Google) and the Floodsite and Peseta websites listed
in Knight & Samuels (2007) are worth perusing. Three websites
that I have been particularly concerned with in recent years are:
www.flowdata.bham.ac.uk, www.river-conveyance.net and www.europa.eu.int/comm/environment/water/flood_risk/index.htm.
REFERENCES
Websites
www.flowdata.bham.ac.uk
www.river-conveyance.net
www.actif-ec.net/library/review_EU_flood_projects.pdf
www.floodsite.net
www.foresight.gov.uk
www.peseta.jrc.es
www.europa.eu.int/comm/environment/water/flood_risk/index.htm
Reports
G. Fleming, Frost, L., Huntingdon, S., Knight,
D.W., Law, F.M. & Rickard, C., 2001, Learning to live with
rivers, Final report of the Institution of Civil Engineers'
Presidential Commission to review the technical aspects of flood
risk management in England and Wales, November, 1-83.
Office of Science & Technology, 2003, Foresight
flood and coastal defence project, Technical Report, Drivers,
scenarios and work plan, Cabinet Office of Science & Technology,
UK Government (http://www.foresight.gov.uk).
Knight, D.W. and Ramsbottom, D.A., 2005, A vision
concerning the hydraulics knowledge base required in river engineering
and associated research needs, Report for Theme Advisory Group
on Fluvial Processes, Defra/Environment Agency Flood and Coastal
Defence R&D programme, 1-34.
Books
Fleming, G., Frost, L., Huntingdon, S., Knight,
D.W., Law, F. and Rickard, C., 2002, Flood risk management, Thomas
Telford, London.
Knight D.W. and Shamseldin, A., 2006, River
Basin Modelling for Flood Risk Mitigation [Eds DW Knight &
A Y Shamseldin], Taylor & Francis, 1-607
Knight, D.W., McGahey, C., Samuels, P.G., Fortune,
D. and Mantz, P., 2008, Practical River Hydraulics using the
Conveyance Estimation System (in preparation by staff from
the University of Birmingham HRWallingford and Jeremy Benn Associates
for the Environment Agency), Taylor & Francis.
Papers
Abril, J.B. and Knight, D.W., 2004, Stage-discharge
prediction for rivers in flood applying a depth-averaged model,
Journal of Hydraulic Research, IAHR, 42, No. 6, 616-629.
Bearne, A., 2006, The effects of climate change
on the Rivers Cherwell and Windrush catchments, Dissertation
as part fulfillment for MSc course on Water Resources Technology
& Management, The University of Birmingham.
Green, M., 2007, The effect of climate change
on the threshold of flooding and extent of inundation along a
reach of the river Tame, Dissertation as part fulfillment for
MSc course on Water Resources Technology & Management,
The University of Birmingham.
Knight, D.W. and Shiono, K., 1996, River channel
and floodplain hydraulics, in Floodplain Processes, (Eds
Anderson, Walling & Bates), Chapter 5, J Wiley, 139-181.
Knight D.W., 2006, Introduction to flooding
and river basin modelling, Chapter 1 in River Basin Modelling
for Flood Risk Mitigation [Eds DW Knight & A Y Shamseldin],
Taylor & Francis, 1-19
Knight D.W., 2006, River flood hydraulics: theoretical
issues and stage-discharge relationships, Chapter 17 in River
Basin Modelling for Flood Risk Mitigation [Eds DW Knight &
A Y Shamseldin], Taylor & Francis, 301-334.
Knight, D.W., Cao, S., Liao, H., Samuels, P.G.,
Wright, N.G., Liu, X. and Tominaga, A., 2006, Floods—are
we prepared?, Journal of Disaster Research, Fuji Technology
Press, Tokyo, Japan, Vol. 1, No. 2, 325-333.
Knight, D.W., Tang, X., and McGahey, C., 2007,
A method for analysing stage-discharge, velocity and boundary
shear stress data for rivers in flood, in Sustainable Water Management
and River Development [Eds Lin Luo & Shaw Lei Yu], Proc.
5th Int. Conf. on Urban Watershed Management and Mountain River
Protection and Development, Chengdu, China, April 3-5, Vol
I, Sichuan University Press, 52-64.
Knight, D.W. and Samuels, P.G., 2007, Examples
of recent floods in Europe, Journal of Disaster Research,
Fuji Technology Press, Tokyo, Japan, Vol. 2, No. 3, 190-199.
Knight, D.W., 2008, Modelling overbank flows
in rivers—data, concepts, models and calibration issues,
Proc. Int. Workshop on Numerical Modelling of Hydrodynamics
for Water Resources, Zaragoza, Spain, June 18-21 June 2007,
Taylor & Francis, 1-20 (in press).
Shiono, K. and Knight, D.W., 1991, Turbulent
open channel flows with variable depth across the channel, Journal
of Fluid Mechanics, Vol. 222, pp.617-646 (and Vol. 231, October,
p 693).
Donald Knight
Professor of Water Engineering, The University of
Birmingham
September 2007
|
