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Dr Jan Verkade, Deltares, Professor Micheal Bruen UCD, Tony Smyth OPW, PJ Rudden, President of EGA,
Dr Amanda Gibney UCD, Evelyn Cusack RTE and Professor David FitzPatrick, Dean of Engineering UCD |
We were very pleased to have Dr Amanda Gibney of UCD School of Engineering to moderate the
presentations by 4 eminent national and international speakers together with
questions from the audience. A full video of the presentations and Q&A
is provided in the link here.
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| Dr Amanda Gibney UCD opens the Panel Discussion |
'The Highs and Lows of Ireland's Weather' are the topic
chosen by Evelyn Cusack of Met Éireann and RTE. A consummate presenter on TV,
she started with a few questions thrown at the audience - 'What do you call this
cloud type? Yes cumulus. If the atmosphere contains 78% nitrogen and 21% oxygen
what else is present? That's right 1% water vapour and gives us our Weather!
It's no wonder that Evelyn is a popular presenter as she instantly engages the
audience.
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| Evelyn Cusack on "The Highs and Lows of Ireland's Weather" |
Did you know that the earth is closer to the sun in
winter than in summer and that the sun heats the ground not the air above the
ground? Did you know that the most powerful greenhouse gas is in fact water
vapour? More men are killed on a Sunday afternoon than at any other time of the
week ..... Playing golf!
She did confirm that the weather last winter 2015/16 'was the wettest on record'.
Climate change is nothing new! It's been around for the
last 4 million years at least and the earth is about 4 billion years old.
Evelyn brought us deep into the world of Physics and Mathematics with Boyle's
Law, Charles Law and the Navier-Stokes Equations which are used to model the
weather in addition to the flow of water in a pipe and air flow around the wing
of an aeroplane.
She introduced us to the growing family of Irish and UK
storms - some male some female - Storm Frank, Storm Desmond, Storm Eva and
Storm Katie and many more!. Evelyn acknowledged that the quality of 'weather
forecasting has improved enormously since the 1980s' due mainly to improved
satellite models.
Regarding climate change she also stated that 'the
temperature rise is unequivocal' and that in climate change terms, the seas are
getting higher, we will have wetter winters causing more flooding and more
storm damage.
Our second Speaker was Dr Micheal Bruen Professor of
Hydrology in the UCD Dooge Centre for Water Resources Research. He started by
telling us that 'floods are natural events and we should not be surprised that
they will happen'! Their impacts can however be mitigated by a combination of
'water storage and conveyance'. There is
however a delicate balancing required as flood storage or relief in one area can impact
adversely on another area upstream or downstream.
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| Professor Micheal Bruen |
He instanced the River Shannon and showed the levels
along its length during the 2009 flood event. As we know the river experienced
even greater and more intense flooding last winter with the worst flooding
around Athlone and downstream of Ardnacrusha at Limerick City. Micheal thought the more likely solutions
in a flat river like the Shannon lay in increased storage say at Lough Rea to
help protect Athlone and/or increasing the cross sectional area of the river
downstream and similarly in Lough Derg to help protect Limerick. There may however be
other resulting impacts from improving storage and conveyance in terms of land
use and environmental issues to be considered.
'You have to target the priority areas to be protected and
you need the legal authority and the hydraulic modelling resources to deal with
the situation. There is also a role for advance flood forecasting and warning
systems based on the most uptodate weather and river modelling.'
Micheal introduced terms about which we were going to
hear more and more as the night went on - 'flood risk' and 'flood risk
assessment'. Also he cautioned that the term 'return period' in terms of
flooding frequency on rivers is misleading to the public. It needs to be
replaced by the 'probability or risk or chance of being flooded in any one
year' as a flood can return twice or three times in subsequent years even on a
river designed to a cater for '100 year return period'.
Echoing Evelyn's view on the history of Irish weather and
resulting flooding, Micheal observed that the
'Annals of the Four Masters record that in 920 AD a Shannon flood
reached the Abbey of Clonmacnoise - 'it didn't reach that level last
Winter!' He remarked. It is also known he said that the monks abandoned Skellig
Michael in the 13th century as 'the weather became colder and more prone to
storms.' Also the bed of the River Corrib dried up in 1178!
In conclusion Micheal was of the view that more local
intelligence should be used to help inform future flood defences. He agreed
that 'climate is changing' and its likely effects need to be included in future
urban and rural planning. All in all we heard an interesting take on what is
required to tackle future challenge of flooding in Ireland. In the next two
presentations we hear how The Netherlands tackle the very considerable
challenge of their very flat country and the ambitious plans of OPW to protect
the most vulnerable parts of Ireland.
Dr Jan Verkade of Deltares (the not-for-profit Dutch national R&D institution for water management and geotechnical engineering) and Delft
University of Technology in The Netherlands had a fascinating story to tell.
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| Dr. Jan Verkade |
Unknown to many outsiders, there was very severe flooding
across The Netherlands in 1953 which after levee barriers failed in the south,
some 136,500 hectares were inundated which claimed over 1800 lives and caused
some 200,000 people evacuated from their homes and some 750,000 people to be affected! Some 10,000 buildings were lost and another 37,300 buildings were
damaged. This happened after a spring tide coincided with a flood surge and
there no warning systems in place.
The impact was catastrophic requiring urgent Government
action as much of the country is below sea level and even marginal rises impact
on additional very large land areas. In addition to make matters worse, most of
the high population areas and areas of principal economic activity (like The
Hague and other major cities together with the Port of Rotherdam) are sited in
the most vulnerable areas to flooding.
In fact even currently, some 30% of the country is below sea level and
areas supporting some 60% of GDP are vulnerable without very robust engineering
defences. Coastal flooding from the North Sea can be severe but equally
problematic is potential fluvial flooding from rivers Rhine and the Meuse.
So what was the Dutch Government response to these
disasters? Economic factors drove a dramatic response to include shortening of
the coastline through new barriers closing off gaps in the coastline. In
addition a 'risk based approach was adopted to flood protection' in accordance
with a new national plan - The Delta Plan and a new company called Delft Hydraulics (since merged into Deltares) was set up to design the flood defences. These barriers
were only completed some 50 years later in 2010 and cost tens of billions to
construct.
In the 1960s a new national risk based strategy was put
in place in The Netherlands where the country was divided into different 'risk
zone' categories and new flood defences designed to cater for the designated
risk. Areas of high economy activity and areas of high population were
prioritised and all dykes and levees raised accordingly.
Since 1960 the population of The Netherlands increased
from 10million to 16million greatly increasing the risk in an area the size of
Munster in Ireland!
A further development of flood risk management is now
in recent years underway to continue risk reduction in terms of any probability of levee
failure, a three tiered approach of structural safety/spatial planning/flood
emergency management and finally 'adaptive planning'. Adaptive planning creates
flexibility based on managing uncertainty including some dyke raising but also
'room for the river' measures to include nature protection if rivers are
widened or deepened.
Jan supplemented his talk with some diagrams and photographs
the most striking of which are illustrated below.
Tony Smyth is Chief Engineer of the Office of Public
Works the statutory body charged with implementation of the EU Floods
Directive. They too have adopted a 'risk management approach' following a major
National Flood Policy Review in 2004. Thus they have identified some 300 areas
which 'are potentially at risk'. These projects now all form part of the Catchment Flood Risk Assessment &
Management (CFRAM) process which will be completed during 2016 and implemented
thereafter. Already parts of Dublin City in Drumcondra on the Tolka and
Ballsbridge on the Dodder together with Clonmel, Carlow, Fermoy, Ennis and
Waterford City have formal flood defences and more now planned.
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| Tony Smyth |
The country has been divided into 6 major areas based on
the principal river catchments ((Shannon, Eastern, South Eastern, South
Western, Western and North Western).
Some 6,500 km of rivers have been surveyed and 40,000 maps produced
based on Lidar surveys.
OPW have sought to ensure that all identified flood
protection works are technically feasible, environmentally acceptable and cost
effective. Neither have they ruled out home relocations or land use
recategorization as a future measure where justified.
A major capital programme of €430m has been identified to
be implemented from 2016 to 2021 for flood alleviation projects to manage the
risk (though not to eliminate it entirely) in a whole-of-government holistic
approach to the challenge. This will also be a major challenge to the engineering
profession in terms of efficiency and innovation though it was noted that all
of the engineered flood barriers and defences recently constructed by OPW held well during the
unprecedented floods of last winter.
All of the projects are subject to Cost Benefit Analysis,
Strategic Environmental Assessment and Public Consultation. The CFRAM maps are
based on a comprehensive analysis and best available information. The maps are
'predictive' and thus the perception of
insurance risk and availability will arise.
The four presentations were followed by a lively Question
and Answer session moderated by Amanda.
A geography lecturer from TCD questioned whether
engineers were open to looking at records beyond 100 years into histories going
into 200 and 500 years? The panel answered that while historical records were
interesting they may not be very useful in predictive terms.
There were questions about the OPW authority to produce a
new scheme for the Shannon. Tony's response was that there was a much greater
interauthority cooperation than realised. There were a lot of competing
interests but the major challenge was financial not institutional. The question
really was what areas most needed protection and at what cost? Last winter the
flood flow in the Shannon exceeded 700 cubic metres per second compared to 130
cubic metres per second to flood the Shannon Callows each winter! Also the
future water supply flow proposed for Dublin in comparison would only extract
some 4 cubic metres per second from the River Shannon flow.
Jan was asked by John McGowan President Irish Academy of Engineering did the building of the flood defences add
to the nation's wealth? Is your country wealthy because you are well protected
from floods or are you well protected from floods because your country is
wealthy? In response Jan agreed that they were related. They have no choice but
to spend the money because of the high risks as in his view if the principal
coastal dyke ring fails, then The Netherlands as a country would probably never
recover. Micheal added that the flooding caused Deltares to be set up which is
now a world leader in hydraulics and flood control.
Evelyn was asked by Kieran Feighan Vice President Engineers Ireland why weather forecasting gas improved so
much? Yes the new Harmony model introduced 5 years ago is more accurate in
topographical terms to fine tune climate modelling. Compliments to Met Éireann!
Kieran also asked is there public support for the expenditure on flood
control? There may not have been initially but now that the public can see the
clear effects yes very much so.
What about use of flood plains in urban areas to increase
flood relief? Ok but depends on the relative land use and how confined the
river sides are. The river banks in Ireland are far less engineered than in
Holland.
Tom Browne of ESB questioned if Lough Ree could offer as
much storage as assumed as the lake levels there were quite low before the heavy
rains of last winter and yet Lough Ree only offered marginal relief to Athlone.
Duncan Stewart, Architect and Environmental Journalist asked about the impacts of climate change
where sea levels will rise more than previously expected and parts of our
coastline might not be capable of defending? Similarly with inland catchments
what can be done on the bigger issues of climate change though he acknowledged
the good work of OPW. Tony agreed that all these scenarios need to be taken
into account particularly with respect to the cities of Dublin Cork Limerick
and Galway. The next phase plan on the EU Floods Directive will have to
address. Micheal agreed it was a societal decision and there will be winners
and losers. There is more uncertainty about sea levels than about river flooding.
Jim Casey of OPW outlined their methodology to deal with
the increasing threat of river flooding.
Dean of Engineering Professor David Fitzpatrick thanked
the Speakers, Moderator Attendees and UCD EGA especially Clare Ryan for her organisation
of the event.
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| UCD Dean of Engineering Professor David Fitzpatrick says thanks to all |
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| Duncan Stewart, Martin Hogan, Evelyn Cusack, Dr Amanda Gibney and PJ Rudden |
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| Professor Michael Bruen, Clare Ryan and PJ Rudden |
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Architect and Television Producer Duncan Stewart and OPW Director of Engineering Tony Smyth
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Professor David Timoney UCD and John McGowan current President of the
Irish Academy of Engineering (IAE) and Former President of Engineers Ireland |
