Author Helen Allister – Project Groundwater Northumbria Lead

Here at Project Groundwater Northumbria (PGN), we spend a lot of time working behind the scenes to make sure groundwater flooding is recognised in policy, funding, research, innovation and community learning, to name just a few.

This Spring we made a deliberate decision to step back from the technical maps, modelling and datasets that underpin much of our work, and instead return to the fundamentals of flooding. Not the basics as such, but the foundations. Quite literally, what is happening beneath our feet. 

By attending a series of Gateshead Council ‘Love Where You Live’ Spring Festival Events, we spent time in former mining communities, talking directly with residents about their lived experience of flooding, and exploring how policy, legislation and the different types of flooding connect to the ground and heritage that shape the North-East today.

During the Ryton leg of the festival tour, we had the pleasure of catching up with Madam Mayor, Councillor Freda Geddes, as well as talking to lots of residents, community groups and local stakeholders.  At all of these events one thing stood out again and again: our people are deeply connected to our industrial and mining heritage, but hadn’t quite joined the dots between the legacy that powered generations of our communities in the past and how it can still influence flood risk today.

Many people in the room had links to local mines, or knew someone who had, or told us stories of family members who physically helped shape the ground beneath our feet. Yet it often came as a surprise that this same underground legacy plays a major role in how groundwater behaves and how flooding can emerge in unexpected places.

You may have heard figures like “1 in 4 properties could be at risk of flooding by the 2050s”, or that around 8 million properties are expected to face flood risk in future decades. These are Environment Agency (EA) statistics, widely quoted in the media and policy discussions.  What many people don’t realise, and what we found ourselves discussing repeatedly at these local events, is that those headline figures do not include groundwater flooding.

“So if 1 in 4 properties are at risk of flooding, why doesn’t groundwater count?”

This was the most common question we were asked this spring.  On the surface, it sounds like a simple one to answer. But the response is anything but. We’d like to share the reasoning behind this lack of inclusion more widely, hence this blog article.

So why is groundwater flooding excluded from national totals?

The EA’s national flood statistics are produced through something called the National Flood Risk Assessment (NaFRA). NaFRA is designed to assess flood risk consistently across the whole country, and it currently includes

• flooding from rivers
• flooding from the sea
• surface water flooding

Groundwater flooding is not included in the national totals or future projections used for those headline figures.  Importantly, this isn’t an oversight or a mistake. It’s a known, acknowledged and usually frustrating limitation, driven by some very real challenges:

• There is no consistent national dataset for groundwater flooding
• Groundwater flooding is highly local, strongly influenced by geology
• It is shaped by historic infrastructure that includes old mine workings, shafts, tunnels and artificial drainage
• Unlike rivers or surface water, groundwater flooding is much harder to model at a local and national scale

Even where groundwater information does appear on public tools (like the EA’s longterm flood risk checker), it is only shown “where data is available”, rather than as a complete national picture.

Why this matters in the North-East

This is where the North-East’s story becomes especially important.

Our region’s coal mining and industrial heritage has left a complex subsurface legacy. Our old mine workings have altered rock layers and artificial drainage routes, and this can change how groundwater moves. Sometimes these historical relics cause it to rise, emerge in places we didn’t expect or spread in ways that don’t follow surface patterns.

When groundwater flooding isn’t visible in national datasets, the risk is that places like the North-East can appear less at risk on paper than they are in reality.  This difference between what people experience locally and what national figures can show is something we hear often, and it has shaped where PGN has chosen to focus its work

Do other studies include groundwater flooding?

Yes and this is where the picture starts to change positively.  

Other organisations do consider groundwater flooding, including one of our project partners, the British Geological Survey (BGS).  They play a key national role in understanding the subsurface and how water behaves underground. BGS research helps explain how water interacts with different types of underground materials, historic mining and buried infrastructure, and why groundwater flooding often behaves differently to other flood sources. We’ll be sharing more soon on how subsurface models (sometimes called Hydrogeological Conceptual Models or HCMs) are used to build this understanding, including work being developed with BGS to improve how groundwater is being recognised in our region. 

Other national studies, including those that inform the UK Climate Change Risk Assessment, also recognise groundwater flooding as an important and growing risk under climate change. However, because this evidence is often place specific and based on developing subsurface understanding rather than a single national dataset, it is not currently reflected in headline national flood risk statistics. This gap between national figures and local experience is exactly what PGN is working to address.

What PGN is doing about it

At PGN, this is exactly the gap we are working to address.  Through our work, we are:

• improving understanding of groundwater flooding behaviour
• highlighting where and why national datasets fall short
• feeding real-world evidence into policy, legislation and consultation processes
• supporting our local authorities and communities who are already dealing with these impacts

Groundwater flooding may be out of sight, but it should not be out of mind!

By connecting our region’s heritage, our changing climate and what’s happening underground today, we can start to build a more complete and fairer picture of flood risk. One that reflects the reality experienced by communities on the ground (and below it).

And if recent conversations are anything to go by, once people start thinking about flooding beneath their feet, they never look at it the same way again.