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NEW CIVIL ENGINEER 05.06.14 | www.nce.co.uk
SPECIAL REPORT: FLOODING
TO PLUG FLOODS
WILL MEAN
GOING DUTCH
The Netherlands is investing heavily in long term flood
prevention, but the UK is hampered by a lack of political
will to pay for protection, Alexandra Wynne finds.
C
ast your mind back a
few months to when
the national media was
awash with images of
political leaders pulling on waders to talk to distressed homeowners – having finally realised
that the winter floods could no
longer be ignored. A swathe
of quick-fix funding ensued to
sort out the worst damage, and
to persuade – or pacify – the
electorate that their plight was
being taken seriously.
As the outrage receded, it gave
way to a predictable dearth of
parliamentary discussion about
how the nation should prepare
itself for the future threat of
waters rising.
Head a few hundred kilometres east across the North Sea
to the Netherlands, and it is a
different story. Despite being
spared any major flood-related
drama this year, defences and
ethics about flood management
remain uppermost in its government’s thinking.
“Every time there is a crisis,
we see there is an opportunity,”
explains Jan Hendrik Dronkers,
director general at Rijkswaterstaat, the Dutch ministry of
infrastructure and the environment, typifying the frank
pragmatism regarding floods for
which his country has become
known.
There is, of course, an underlying logic to why the Dutch deal
with the flood threat head-on:
60% of the country’s population
live below sea level, which accounts for over 27% of land mass.
And then there was the 1953
flood, which killed 326 in the UK
and 1,800 in the Netherlands.
The disaster marks the point at
Special
report
which both countries realised
the true extent of their vulnerability to flooding. The Thames
Barrier and the Dutch Delta
Works iconically represented the
effort to prevent a repeat of the
disaster.
Flood events in the Netherlands in 1993 and 1995, which
Dronkers describes as near misses, gave rise to more flood protection plans, notably the €2.3bn
(£1.86bn) Room for the River
scheme. But the Netherlands is
less interested in responding to
events on a “needs must” basis;
it is more keen to pre-empt
them.
A milestone policy that puts
“The secret of our
programme is that
if the sea level
changes, we expect
we will be able to
deal with that”
Jan Hendrik Dronkers,
Rijkswaterstaat
this ethos into action, contained
within its Delta Programme
annual report, will go before the
Dutch parliament later this year.
The programme simply aims
to protect its people from water
and ensure a freshwater supply.
But added to the 2014 report
is a set of principles for how
the country will manage these
challenges – not just in the short
term, but also the long term.
They represent a new approach
for the Dutch.
The policy sets out major decisions that need to be addressed,
along with generating new
risk-based design standards. It
is a programme that requires
collaboration between national,
local and regional governments,
civil organisations, businesses,
knowledge groups and water
boards.
The programme’s enactment
will secure £13bn of government
funding for schemes between
2017 and 2028. And therein lies
the ambition. Rijkswaterstaat
safety and water use director
Roeland Allewijn says that it is
still a pretty modest approach
given the potential threats from
climate change. Of the planning
for 2028, Allewijn says: “We call
that relatively short term.”
The Dutch government has
no interest in debating whether
climate change is real. Instead,
there is an acceptance that it is
happening, as well as an awareness of the lack of certainty
over its possible effects. But the
government’s plans will help it
to cope with any of the projected
scenarios.
“It is an adaptive strategy
because we are not certain what
will happen in the next decades,”
Dordrecht dream: Plan Tij
UK reality: Somerset Levels
www.nce.co.uk | 05.06.14 NEW CIVIL ENGINEER
Netherlands: Room for the River project allows
the River Dommel, the Rhine and its tributaries to
discharge beyond their banks
“It is an adaptive
strategy because we
are not certain what
will happen in the
next decades”
Jan Hendrik Dronkers,
Rijkswaterstaat
THE NETHERLANDS FACT FILE
North and South Holland lie
on the estuaries of two major
European rivers, the Rhine and
the Maas.
The Netherlands is a low-lying
country, with about 27% of its area
and 60% of its population below
sea level. Some 60%
of the country is either under sea
level or at risk of regular flooding
from the North Sea or the Rhine,
Maas and Schelt rivers and their
tributaries.
Most of the country is very
flat, except the foothills of the
Ardennes in the south east
and a hilly region in the centre.
Significant areas have been
gained through land reclamation
and preserved using an elaborate
system of polders and dykes.
Polders are flat stretches of land,
surrounded by dykes, where the
water table is controlled artificially.
From the 16th century onwards,
windmills were used not just to
keep the land dry, but to drain
entire inland lakes.
Work on the Delta Project,
a chain of dams protecting the
provinces of Zeeland and South
Holland from the North Sea,
began following the disastrous
floods in 1953, and ended in
1997 with the completion of a
storm surge barrier in the Nieuwe
Waterweg.
The barrier has two enormous
hinged gates that can be lowered
in severe weather to close off
the 360m wide waterway. It
protects greater Rotterdam’s 1M
inhabitants from flooding.
says Dronkers. “The secret of our
new programme is that if the sea
level changes, we expect we will
be able to deal with that.”
The impact of more and
extreme storms, a sea level rise
of between 200mm and 850mm
over the next century, increased
erosion, more intense rainfall,
summer droughts, salt intrusion
and the challenge of spatial
development have all been
considered.
The outcome is a risk-based
approach, which means anyone
who lives in an area protected
by the country’s dykes, or in an
area of high economic value, will
be protected to a standard of 1 in
100,000 years, or in other words,
an annual risk of death as a
result of flooding of 0.001%.
In addition, critical infrastructure will be further bolstered.
The importance of infrastructure
– both that which needs protecting and that which is giving
protection – is recognised at the
highest level.
There is an emphasis on
spatial development, which is
significant. New dykes are a big
part of the new programme,
but this aspect of the planning
is emblematic of a pragmatic
acceptance by the Dutch that not
everything can be done to hold
all the water back, for everyone,
all of the time. Instead, there is
now a belief that the intrusion of
water should be accommodated
and worked with where appropriate.
The Room for the River
project, now well under way,
adopts this methodology. A river
is given more space to discharge
beyond its original course, while
at the same time, people are
moved away from behind inadequate dykes into new homes on
safer ground.
In the days following NCE’s
visit to the Netherlands came
the publication of 10 “golden
rules” for flood management
by an influential group that
includes the World Wide Fund
9
for Nature, the Chinese government and a number of leading
international experts from the
UK, South Africa, Australia and
the US. Among the rules is one
calling for some flooding to be
promoted as desirable.
“Floodplains provide a fertile
area for agriculture and a variety
of ecosystem goods and services
to society, including natural
flood storage,” says the report, a
summary of which was published in the International Journal of River Basin Management.
“Making room for the river and
the sea, utilising the natural
ability of this space to accommodate flood waters and dissipate
energy, maintains vital ecosystems and reduces the chance of
flooding elsewhere.”
The Dutch Room for the River
project pre-empted this, but fits
the bill. The scheme was conceived in direct response to the
rising river levels experienced
in 1993 and 1995, which, in the
case of the latter, led to 250,000
people being forced from their
homes. The assumption of
the Dutch that the country is
protected robustly meant that
a forced evacuation was unexpected.
“We were shocked,” says
Rijkswaterstaat’s director of
infrastructure realisation for
Room for the River Martin
Hoenderkamp. “We thought we
were prepared for everything.
We thought evacuation was for
other countries.”
The area available for the
rivers has simply decreased over
the centuries. High dykes confine the rivers and an increasing
number of people are living
behind them. At the same time,
the land behind the dykes has
sunk due to soil subsidence.
Add to that more frequent and
more intense rainfall, and the
rivers need to discharge more
water to the sea. A flood without
the Room for the River scheme
would put the safety of 4M
people at risk.
Construction work on the
project began in 2007 and is due
for completion next year. Although to call it just “a project”
is misleading as the work entails
creating room for the river at 39
locations.
Nine measures are being deployed (see diagram) and there
is a huge emphasis on spatial
planning where the dykes are
being moved inland.
The combined effect will be
to increase the maximum
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NEW CIVIL ENGINEER 05.06.14 | www.nce.co.uk
SPECIAL REPORT: FLOODING
discharge of the River
Rhine and its tributaries from
15,000m3/s to 16,000m3/s, although Hoenderkamp says, for
the longer term, the aim should
be to look at accommodating
discharge of 18,000m3/s.
Paid for by central government, the project is being
delivered by local and regional
governments in partnership with
water boards and private sector
partners.
With the number of people affected – the scheme will protect
4M people currently at risk –
and the great number of scheme
partners involved, stakeholder
management is paramount. It is
not a job for the faint hearted.
The Noordwaard project is
one component and it is an area
that illustrates this stakeholder challenge more than most.
Farmers have inhabited the polders behind the dykes here for
many generations. But now the
area is being “de-poldered” and
given over to the rivers when
required to create a reduction in
river levels.
Dwellers will be able to remain
in the area if they desire – on
new polders. But essentially a
huge campaign to help move
farmers away is going on.
“From the view of the civil
engineer, it’s not so complicated
a project, moving some earth
and lowering the river levels,”
says Hoenderkamp. “Technically
it’s not that complicated, but the
difficulty is that everyone has an
opinion.”
Discussions with the Noordwaard’s farmers began in 2003,
focusing on offers of helping
people to build homes on higher
polders, or moving away from
the area. “Those early discussions were very difficult,” says
Noordwaard stakeholder manager Ralph Gaastra. “But when one
household has decided to go, you
can see more will come around.”
It is not all about moving away
from the area; it is also intended that the areas affected by
encroaching rivers will benefit
ecologically in some ways and
will offer greater recreational
use.
On visiting the rural and
agricultural community at the
heart of the Noordwaard Polder
scheme, it is almost impossible
not to draw parallels with the
properties built on flood-prone
land closer to home on the
Somerset Levels. Yet the stark
contrast is in knowing that the
UK is nowhere near to having
SAND ENGINE LOCATION
Noordwijk
0
km
10
Katwijk
The Delta Programme’s €16bn
(£13bn) government funding for
schemes between 2017 and 2028
includes:
€5bn
For ongoing projects, including
Room for the River
€4bn
Scheveningen
High Water Protection Programme
SAND ENGINE
€6bn
The Haag
Delflandse Kust
Operations and maintenance
Westland
Delft
€200M
Fresh water supply
Rotterdam
€1bn
Replacement programme for
hydraulic structures
these kinds of conversations
with people residing in floodprone zones. Our politicians
are some way off accepting that
encroachment of the seas and
overflowing rivers onto property
will be inevitable.
Nonetheless, the UK is doing
“The really big
difference is in
government funding.
In a sense, it’s
the government
saying we need to
experiment with
new techniques for
the security of our
future”
Jaap Flikweert,
Royal HaskoningDHV
more and more to seek to understand the threat; for instance
in the wake of the winter floods,
work is afoot to investigate the
risks from groundwater flooding,
which played a significant role in
inland properties being inundated.
“The issue of groundwater
flooding is certainly not being
ignored,” says Environment
Agency director of flood and
coastal risk management David
Rooke. “But it is very difficult
to predict where groundwater
flooding is going to take place
if you haven’t got a historical
record of flooding.
“The geology can be very
complex. So one of the areas that
we are working on is with the
government office of science, the
British Geological Survey, the
Centre for Ecology and Hydrology and ourselves to see how
we can get better predictions of
where there will be groundwater
flooding. This will then allow
local authorities, whose responsibility it is as they’re the lead
local flood authority for groundwater, to then take action.”
And the issue in the UK is not
necessarily about intent, but
rather the funding required.
In the UK, the message was
clear when in the October 2010
Comprehensive Spending
Review the government cut the
Environment Agency’s funding
settlement by £170M. In May
2011, the Agency launched its
new partnership funding model
to top up the shortfall, which
meant any new flood defence
project must not only meet cost
benefit analysis criteria, but also
had to attract funding from beyond the government’s coffers.
Since that 2010 spending
review, the government has
come around to the benefits of
investing in the strategic road
network, for example, but funding for building and maintaining
flood defences is still wanting.
The recent knee-jerk reactions
to public pressure with discrete
panic funding to fix the recent
flood damage, along with the
www.nce.co.uk | 05.06.14 NEW CIVIL ENGINEER
11
HOW THE SAND ENGINE IS EXPECTED TO DEVELOP
0 YEARS
5 YEARS
10 YEARS
20 YEARS
Beach protection: A 2km hook-shaped peninsula, extending 1km out to sea, has been formed to
protect the coastline off the south of Holland. It is hoped the tide will disperse the deposited sand
where it is needed and remove the need for costly beach replenishment over the next 20 years
ensuing dampening of rhetoric
on floods, suggests little is set to
change.
In the Netherlands, the funding is there and the risk-based
approach means cost benefit
analysis is not strictly applied to
any given scheme – it simply has
to make sense.
“Our water infrastructure is
one of the pillars of our national
economy,” says Allewijn.
This unchallenged assertion
that investment in water infrastructure is the right thing to do
seems to allow developers the
freedom to come up with new
ideas and experiment. As a result, there exists a fearlessness in
the way schemes are conceived.
The Sand Motor – or Sand
Engine – coastal protection
scheme typifies this. In 1990 the
government decided that erosion
of the Netherlands coast had
to be stopped and it began to
think of other ways to maintain
it, identifying weak spots that
needed reinforcement.
The problem has been a long
term issue for the Netherlands;
each year the sea takes sand
away from the coastline, leaving
the below sea level country
exposed.
Every five years, Rijkswaterstaat would carry out a beach
replenishment programme,
placing sand on the coast and
just offshore, to make up the
shortfall. But an alternative, and
innovative, plan was hatched.
Instead of fighting the sea,
perhaps its natural inclination
could help the cause of protecting the country. So between
March and November 2011,
Rijkswaterstaat and the provincial authority of Zuid-Holland
created a 2km wide, hook-shaped
peninsula, extending 1km into
the sea.
Suction hopper dredgers
claimed sand 10km off the coast
and deposited it to form the
peninsula.
The rhetoric used is “building
with nature” but the logic is if
the sea is inclined to move sand
around, perhaps it could do hu-
mans’ work of replenishing some
sand-deprived areas.
If the Sand Engine fulfils expectations, sand replenishment
off the Delfland Coast will be unnecessary over the next 20 years.
Wind and currents started to
shift the Sand Engine as soon
as it was in place. Two and a
half years in, the shape-shifting
peninsula has behaved broadly
as expected.
“It is very difficult
to predict where
groundwater
flooding is going
to take place if
you haven’t got
a historical record
of flooding”
David Rooke,
Environment Agency
The project team is acutely
aware of the scheme’s “world
first” potential, and a massive
academic effort is being made
to watch and learn from what
comes of the scheme. If it works,
the plan is to roll it out elsewhere, and interest is already
being piqued abroad, including
in the UK.
The question arises as to
whether a similar project could
or would be undertaken here.
“You could argue this is a
relatively simple section of
coastline to deal with, particularly compared with the UK,” says
Jaap Flikweert, who is director of
water governance and strategy
at Royal HaskoningDHV, who
worked on the sand engine.
“The really big difference is in
government funding. There is
a large element of vision. In a
sense, it’s the government saying
we need to experiment with new
techniques for the security of our
future.”
National Flood Forum chief
executive Paul Cobbing is
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NEW CIVIL ENGINEER 05.06.14 | www.nce.co.uk
SPECIAL REPORT: FLOODING
HOW THE RIVER WILL BE GIVEN MORE ROOM
How the river will be given more room...
HOW THE RIVER WILL BE GIVEN MORE ROOM – THE DIFFERENT METHODS
Lowering of floodplains
Deepening summer bed
Water storage
Lowering (excavating) an area of the
floodplain to increase the room for the river at
high water levels
The river bed is deepened by excavavating the
surface layer of the river bed. The deepened
river bed provides more room for the river
The Volkerak-Zoommeer lake provides for
temporary water storage when exceptional
conditions result in the combination of a
closed storm surge barrier and high river
discharges to the sea
Dyke relocation
Lowering groynes
High water channel
Relocating a dyke inwards increases the
width of the floodplains and provides more
room for the river
Groynes stabilise the location of the river and
ensure that the river remains at the correct depth.
However, at high water levels groynes can form
an obstruction to the flow of water in the river.
Lowering groynes increases the flow rate of the
water in the river
A high water channel is a dyked area that
branches off from the main river to discharge
some of the water via a separate route
Depoldering
Removing obstacles
Strengthening dykes
The dyke on the river side of a polder is
relocated inwards. The polder is
depoldered and water can flood the area at
high water levels
Removing or modifying obstacles in the river
bed where possible, or modifying them,
increases the flow rate of the water in the river
Dikes are strengthened in areas in which
creating more room for the river is not an
option
reticent about the applicability
for the UK. “The Dutch approach here is refreshing because
in the UK benefit/cost would be
foremost,” he says.
It is possible that the UK
could adopt such an approach,
but so far the interest is not coming from central government.
“The Crown Estate has come
to us [Royal HaskoningDHV]
to develop how this could work
in the UK,” says Flikweert, who
adds that consultant Arup is also
working with it on the idea here.
But it is unlikely to be
deployed at a national level, according to Flikweert. “You could
say that here in the Netherlands
the Sand Engine is a national
initiative,” he says. “In the UK, it
would always have to be a local
initiative.”
Nevertheless, the team has
begun presenting the idea and
its potential to the Environment
Agency. High up on the list for
places that have the potential
to benefit from the approach is
“The Crown Estate
has come to us
to develop how this
could work in the UK.
In the Netherlands
the Sand Engine is a
national initiative,
in the UK, it would
always have to be a
local initiative”
Jaap Flikweert,
Royal HaskoningDHV
Lincolnshire, whose coastline
bears the greatest resemblance
to where the Sand Engine is
in the Netherlands, and it is
an area that currently relies on
beach replenishment of around
500,000m3 a year, according to
Flikweert.
Most helpful right now would
be to develop an academic community in the UK, he continues,
but in the medium term, local
ownership of such a scheme
would be vital. “The Dutch example shows that it can’t happen
if there is no local ownership
and local drive,” he says.
Which means it all sounds
more difficult given the reticence
in the UK to adopt such experimental methodologies.
“There is an acceptable
uncertainty about how the
Sand Engine will perform,” says
Flikweert. “To convince the Environment Agency and the local
authorities in the UK, the uncertainty will have to be less than
there was in the Netherlands.”
Despite their obvious breadth
of experience there is little
arrogance from the Dutch and
a willingness to learn not just
from their own experiences but
also from abroad.
Allewijn cites Hurricane
Katrina, which devastated
New Orleans in 2005, and the
film about the perils of climate
change presented by former US
vice president Al Gore, An Inconvenient Truth, as major influences on the Delta Programme’s
ambitions.
But on a smaller scale, there is
high regard for how well the UK
reached out to residents affected
by the recent floods. Warning
systems in particular are praised
by the Dutch for being far ahead
of its own. There is a concern,
says Allewijn, that the Dutch
are too complacent in assuming
the government has done such
a great job of making them safe
from the floods; more needs to
be done to communicate the
continued risks, he believes.
There is much that
flood-threatened countries
are doing to learn from one
another’s specialist knowledge,
but unless UK politicians have
a change of heart over the economic value of water infrastructure, it seems likely that innova-
tion and change will continue to
flow from the Dutch.