Risks, the EU and good decision making

South Yorkshire faces at least two worrying economic threats as we reset our international trade agreements. One is a potential short-term fall in infrastructure investment. The other is long-term climate change damage to both new and existing infrastructure assets. The good news is that by solving the second I think we can help to resolve the first.

That means focussing on many environmental factors. A busy industrial and business community like the Sheffield City Region (SCR) has to cope with growing traffic congestion, noise pollution and waste streams that include plastic. Equally importantly, good air quality is now being seen as a right.

Some UK local authorities are planting hedges around school playground – and limiting parent waiting time – to minimise ‘bad’ air that affects children’s health. We are also experiencing more carbon- and toxin-heavy moorland fires, plus long droughts and water shortages.

A regional and global problem

However, heavy rain is clearly becoming a major systemic problem, confirmed not only in the UK by recent unprecedented flooding when the River Steeping broke its banks at Wainfleet in Lincolnshire but also with landslides, havoc and hundreds of thousands of displaced people in China.

Later, I would like to look more closely at a couple of practical example of what we can do to protect high population-density mixed urban/rural communities in the SCR, the wider Pennine region and beyond.

But I believe we must see this in the context of the UK’s new commitment to net-zero greenhouse gas emissions by 2050, and a growing realisation that a trigger point is being reached where reversing crucial impacts of global warming could become increasingly difficult if not impossible.

Erring on the sustainable side of caution

Two news events are particularly important. One is that the Environment Agency (EA) feels that entire UK communities may have to be moved away from coasts and rivers if global temperatures rise by 4C (https://www.gov.uk/government/publications/national-flood-and-coastal-erosion-risk-management-strategy-for-england).

The other is that in addition to natural barriers and flood relief systems, the EA says we now need to build “climate-resilient” communities, homes and businesses. Bigger walls alone are no long-term solution (https://www.gov.uk/government/news/environment-agency-chair-calls-for-new-approach-to-flood-and-coastal-resilience).

I also thought it might be interesting and useful to remind ourselves briefly that on a geological scale we live on a very vulnerable planet. The catastrophic events listed below will almost certainly happen one day. What makes them less worrying today is their extremely low probability – we hope – compared to man-made climate change where we can take immediate action.

Hollywood scenarios?

Most people are probably aware of Yellowstone National Park’s super-volcano which powers geysers like Old Faithful and will spew ash over much the US when it next mega-erupts. An eruption is expected within a century. But the odds of massive devastation are one in 10,000, the same as Earth being hit by a very large asteroid, according to the U.S. Geological Survey.

The last three super-explosions were 2.08, 1.3 and 0.631 million years ago – the gap between the last two being 0.669 million years. Does this mean the next is imminent? In human terms, no. However, many years of “volcanic winter” from ash-filled skies would end the global economy.

All at sea

The Azores stand on the Atlantic mid-ocean ridge and a boundary between tectonic plates running to within 330 km of the North Pole. It is estimated that a massive landslide on the islands’ western side and ensuing tsunami would devastate the US eastern seaboard, the global economy and hit the UK. A 1607 tsunami is thought to have drowned more than 2,000 people around the Bristol Channel.

When Iceland’s Eyjafjallaj?kull volcano erupted further north on the ridge in 2010, fine airborne particles made jet flight impossible. Other volcanos could erupt on a regular cycle for longer periods; this probably happened last before the Wright brothers first flew at Kitty Hawk in 1903!

Lurking deep underground

Historically, volcanoes have been linked to poor European harvests. Following an eruption of Indonesia’s Mount Tambora in 1815, 1816 became known as the “Year Without a Summer”. Hundreds froze to death. The northern hemisphere suffered major food shortages.

Other dangers may lurk beneath us. The Mediterranean is volcanically active; Italy's Vesuvius has been especially destructive. However, deep fault-lines that haven’t moved for eons lie under Western Europe. When they do eventually slide, the pent up forces will be enormous.

Deadly twin

Space could be equally dangerous. Scientists in the 1980s noticed that mass species extinctions on Earth occur at 27 million years intervals. They put this down to long timespan astronomical events and the theory was born that the Sun’s has a small binary twin – Nemesis.

The idea, which has since fallen out of favour, was that Nemesis’ gravity disturbs icy rocks in the hard-to-detect Oort cloud beyond Pluto which travel around the Sun in long-term, elliptical orbits before hurtling as comets towards us in the inner solar system.

Add thoughts of an all-engulfing black hole being created in a giant collider at CERN (European Organization for Nuclear Research), plus hypothetical cosmological models of the Big Freeze, Big Crunch, Big Change and Big Rip ending the universe that the Big Bang started, and we have a full deck of worries. If you are of a nervous disposition, it may be better to think of fluffy kittens!

Back to the present

The point is that we can always scare ourselves to death. The probability of these events happening in the near future is very, very, very low. However, if we apply the same criteria to high-probability events, the conclusion is different. As one author explained, “If I said to you that there was a one in 20 chance that if you crossed the road you would be squashed, you wouldn't go near it."

More concerning I think is a new study by scientists who calculate that sea level rises caused by global warming of 5C rather than 2C, and faster ice melting in Greenland and Antarctica could displace circa 200 times more people than the estimated one million refugees moving out of Syria. The world would lose 1.79 million square kilometres - equal to the size of Libya - of important food-growing regions such as the Nile delta (https://www.pnas.org/content/116/23/11195).

Immediate issues

What are the implications for hard-working areas like the SCR and other new and traditional industrial areas which rely on a modern manufacturing infrastructure for their wealth-generation and export potential inside or outside the EU?

In the case of flooding, there are three. Firstly, we must protect individual properties. Secondly, we need to consider wider flood plains problems. Thirdly, local SUDS (sustainable drainage system) solutions are often easy-to-construct and easy-to-manage, cost-effective natural alternatives.

Enzygo – solution not problems

A good starting point for identifying optimum solutions is auditing and analysing current conditions, plus likely future factors, against a backdrop of what climate change might bring. The following two case studies are West and South Yorkshire examples of how hydraulic modelling can help.

1. Industrial site, Calder Bank, Brighouse - We used hydraulic modelling to investigate the circumstances around flooding on Boxing Day 2015 https://www.enzygo.com/projects/defence-raise-flood-risk-assessment/. Peak flow for the River Calder measured approximately 20km upstream had an estimated return period of more than (>) 200-years. Using this information, the site owner proposed raising an existing flood wall and/or embankment to protect against damage from future events of a similar magnitude.

Adjacent impacts - In parallel, the Environment Agency (EA) wanted modelling evidence to prove no ‘adverse’ flood risk impacts would be created upstream or downstream if the work went ahead.

Revised model – Enzygo found instability issues in the existing EA Calder and Canals Model. We trimmed the model to remove these and focussed on areas immediately upstream and downstream of the site. This revised baseline model was then used to represent three defence-raising scenarios.

Climate change - Very importantly at this stage, allowances were made for climate change; the trimmed model was also run for a full suite of relevant return periods.

Results – Defence-raise modelling showed that the Baseline standard of protection (SOP) for the site’s defences is high (1,000-years). However, the actual defences have a quoted build SOP of 50-years. Even so, the model could still be used to assess the impact of raising defences on flood risks both upstream and downstream.

Wider effects – Equally importantly, the model was used to assess the potential impact of the proposed work on flood depths elsewhere in Brighouse. This was found to be generally negligible.

Benefits – From a client perspective, once both modelling and results were approved by the EA, Enzygo used them to provide advice about the preferred defence-raise option. We were subsequently invited to manage and submit the Flood Risk Activity Permit for future work.

2. Housing development, Low Valley, Darfield – We used hydraulic modelling again to understand flood risks and show that the EA’s Flood Map for Planning needed updating. Specifically, we showed that removing an old bridge blocking the flow of the River Dove and replacing it with a new structure elsewhere stopped out-of-bank flooding which affected properties (https://www.enzygo.com/projects/flood-modelling-low-valley-darfield/).

Increased accuracy - Enzygo helped a residential developer and Barnsley Metropolitan Borough Council with the assessment, flood modelling and project management of a Flood Map Challenge (where local knowledge is more meaningful) for the South Yorkshire site.

Existing situation - A planning application for the south bank of the River Dove was allowed on condition that there would be no flooding. A Grant in Aid application to the EA and Defra for a suitable flood defence scheme led to an outline grant of ￡1.2 million.

Modelling – Enzygo constructed a 1D2D linked hydraulic model of the River Dove and nearby Bulling Dike using Flood Modelling software, updating existing Opus and EA models for the same area. Our model covered 3.7km of the River Dove and 2.3km of Bulling Dike made up of 60 cross-sections with eight in-channel structures over a flood plain area of 1.6km2.

Refinements – Sensitivity testing took into account in-channel and floodplain roughness, plus the seasonal growth of vegetation on flood risk. We proved that 28 properties – 26 residential – and an electricity substation were at risk.

Flood mapping results – Enzygo showed a reduced flood extent in all modelled events compared to the EA’s online flood map. This was put down to removing the old Pitt Bridge, replacing it with New Bridge and taking out a major flow restriction.

Updated mapping data – The EA accepted our modelling results, updating its current Flood Map for Planning to show the new fluvial flood extents. Crucially, this took the site out of Flood Zone 3 and reclassified it in Flood Zones 1 and 2.

Continuing Enzygo involvement – Following this success, we have provided hydraulic modelling for flood map challenges across the wider property and development sector.

Happy to discuss these studies and any other flooding issues at any time. Please contact me directly to chat further.