21 May 2020 / www.theengineer.co.uk
feasibility” studies have been carried
out – largely funded by local businesses
to the tune of around half a million
pounds - and the team is now focused
on drumming up some government
interest in the project.
Nevertheless, Hatley reports
signifi cant progress in understanding
how the scheme might fi t into what is
an unusually complex environment.
“Hull’s quite a unique place in that it’s
one of the few places in the UK that is
vulnerable to all four types of fl ooding:
pluvial (rainfall), fl uvial, groundwater
and tidal,” he said. “It is at the centre of
all the risk factors, and the project has
had to take into account the knock-on
eff ects”
so effi cient that everybody naturally
migrates to it. 100 per cent of the
through traffi c goes straight to the new
road because its quicker.”
Whilst the studies performed so
far justify local enthusiasm for the
project, there is still much to be done
before it even gets close to the approval
stage, and Hatley and the team are now
hoping to a ract government funding
to carry out more exhaustive scientifi c
and modelling work. “Whilst we’ve
got two sets of model data that show
the same eff ect we’re a long way from
being able to prove defi nitely that there
aren’t other problems,” he said. “We’ve
done everything you can do sensibly
that tell you that this is worth spending
money on, we’re now at the point where
we need to take modelling of the river
system up to a whole new level. ”
As well as augmenting the work that
has already been carried out, this next
phase of studies would looksat a host of
other factors such as the cyclical longer
term changes in the estuary that would
need to be properly understood if the
lagoon were to be built.
Further modelling would also be
needed to understand how the lagoon
could be designed to work in harmony
with the sensitive natural habitats in
the estuary. “If we design things in the
right way we can start doing things
like supporting the habitat which
the estuary may need to support its
conservation status,” said Hatley. “For
example. Could we create more areas of
intertidal mudfl at to support migrating
bird populations?”
Assuming all of these challenges
are met, Hatley estimates that if
government were to wade in with the
support that’s required to take the
project to the next level the project is 10
– 15 years away from fruition.
With Covid-19 currently wreaking
havoc on the UK economy it’s perhaps
fanciful to think that funding will
be forthcoming any time soon. But
as Hatley and his team are keen to
stress, Lagoon Hull is as much about
stimulating economic growth as it
is about fl ood protection. And in the
aftermath of the current crisis, the
scheme might provide just the kind
of economic stimulus that will be
required.
In an eff ort to understand these eff ects the team has been
working with a number of specialist organisations – including
marine consultancy ABPmer - to model the impact of the
scheme.
This modelling represented a make or break moment for
the project and Hatley was prepared to be disappointed. “We’re
used to the idea that if you to build in the fl ood plain you make
it worse, and the immediate assumption from most people
was that if you build a structure out in the Humber estuary
you’re just going to fl ood the other side of the estuary. At best I
was hoping it would be a fairly neutral impact and at worst we
were thinking it could be the end of the project.”
However, the modelling, which was carried out by two
separate independent teams, told a very diff erent story,
suggesting that, thanks to the complex mix of conditions
found in the estuary, an obstruction would actually make
water levels lower rather than higher.
What’s more, an additional simulation study carried out by
researchers at the University of Hull found that if the lagoon
had been in place during the 2013 tidal surge, the city would
have had 100 per cent protection with the rest of the estuary
seeing an 80 per cent reduction in fl ood volume. This group
also found that if the same tidal surge occurred in 2108, when
sea levels are expected to have risen by one metre, the lagoon
would continue to provide 100 per cent protection for Hull
with the rest of the estuary seeing a 33 per cent reduction in
fl ood volume.
As well as
protecting the city
from tidal fl ooding, the
six mile long structure
would also create a
new waterside area
Hull’s quite a unique
place in that it’s one of
the few places in the UK
that is vulnerable to all
four types of flooding
The new route could
remove through-traffi c
from Hull city centre
The models have also shown the that lagoon could be used
to support eff orts to reduce fl uvial fl ood risks by providing
large scale storage for storm water from the River Hull and
Hull frontage storm outfalls during high water periods. “If the
river drains into the lagoon where you can control the water
level, then in storm events you can stop the tide coming in and
you can enable the river systems to continue to drain more
effi ciently,” explained Hatley. “If you know that rain is coming
into the river and that river’s going to get to your lagoon then
you can run the level down in the lagoon on the preceding tide.
If you run even a metre off the lagoon, that gives you 5 million
cubic metres of storage water and at the next tidal cycle you
can empty that. So every 12 hours you can a enuate a fl uvial
surge event to the tune of 5 million cubic metres.”
As well as estuary modelling, the group has also worked
with the Highways agency to simulate the new road’s impact
on the city’s traffi c. Once again, said Hatley, the results were
extremely promising. “The models show that the route is
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