Be aware of flood risks when house buying near watercourses in Wales warns flood expert

IF you’re thinking of buying a house by the sea, river or any watercourse in Wales, be aware of the risk.

That’s the message from Natural Resources Wales (NRW) flood expert Jeremy Parr.

“I wouldn’t go as far to say don’t do it, but you need to be conscious of what the risks are,” he said.

Last winter’s storms peaked in February, culminating in Storm Dennis when 2,765 properties flooded in South Wales.

The statistics are sobering: 51 of Wales’s 231 river gauges recorded their highest ever levels during the storm, enough water to fill an Olympic-sized swimming pool rushed through Pontypridd every three seconds at its peak, and 158 flood alerts, warnings and severe warnings were issued.

Image showing rainfall intensity over a 48-hour period during Storm Dennis (pic supplied by Natural Resources Wales)

During February, just over 50cm of rain – getting on towards two feet – fell at Lake Vyrnwy, Powys.

As well as the physical and economic toll was the human one.

A study has found a significant link between being forced out of your property due to flooding and symptoms of depression, anxiety and post-traumatic stress.

Householders can be in-limbo for months or even years, and risk not being able to re-insure their property.

“Every time it rains they are worried about it – particularly elderly people and children,” said Mr Parr, NRW’s head of flood and incident risk management.

“The mental health impact is huge.”

NRW has published the findings of a review of the February floods, which concluded that defences largely held firm – although some were over-topped – but that the environmental watchdog struggled as an organisation.

It failed to issue 12 flood warnings, and three were issued late.

NRW’s resources, said the review, “could not fully cope with the size of the task at hand for an event of this scale and significance”.

And it said there were no silver bullets.

More intense rainfall is likely in a warming climate, while the Met Office has projected sea levels rise in Cardiff of between 27cm and 1.13m by 2100, depending on various factors.

Jeremy Parr, head of flood and incident risk management at Natural Resources Wales

Granted, spring 2020 was incredibly dry, but more deluges are forecast for Wales on October 29 and 30.

It seems that building our way out of trouble won’t work, so tough calls have to be made.

There are considered to be 117,100 properties at high risk of flooding in Wales, 44,668 at medium risk and 83,350 at low risk.

The Welsh Government, which published an updated flood risk management strategy this month, wants a big conversation on the topic.

Its strategy said homes and businesses in 40 coastal areas may need to relocate by 2100.

Coastal flooding and erosion are addressed in four shoreline management plans covering Wales.

They throw up four options: maintain or improve existing defences, advance the existing defence line, allowing the shoreline to retreat in a managed way, or shelve defence investment and let nature take its course.

“Difficult decisions will need to be made as to where investment is directed and how we adapt,” said the Welsh Government’s strategy.

This is what NRW’s Mr Parr had to say to the Local Democracy Reporter Service.

Question: Do you consider flooding from rainfall to pose a greater risk in Wales than coastal flooding?

Answer: Around 90,000 properties are at risk of fluvial (river) flooding, 71,000 from tidal (the sea), and 131,000 from surface water (drains, saturated ground), so you would say surface water water is the biggest risk, but it’s not necessarily the worst flooding.

It tends to be low level – not so deep, not so fast, not so dangerous.

Flooding from the sea and rivers is a lot worse.

The future is a bit more speculative. There are projections of a 1.13m sea level rise by 2100 in some scenarios, but when you add storms, waves and surges it’s more than that.

Wales has a lot of population and infrastructure on the coast. But it has a large population by rivers inland.

Question: How much does NRW spend a year on new flood defence assets and how much maintaining existing flood defence assets, and is it enough?

Answer: We get around £10 million to £20 million of capital money a year from the Welsh Government for new and existing defences. (Councils also receive funding).

We also get around £6 million in revenue spending on flood defence maintenance – things like new seals, and cutting back weeds.

It’s enough in terms of keeping on top of what we need to keep on top of, but we could spend more. It’s challenging.

Question: How does NRW decide where to build new flood defences, and are new ones being planned for Swansea, Carmarthenshire and Neath Port Talbot?

Answer: It’s a combination of understanding where the risks are – we spend a lot of effort on mapping and modelling – and using information about historical flooding.

It’s important that historical flooding does not drive everything. Just because your area hasn’t flooded before doesn’t mean it won’t flood.

In Ammanford we’re at the early stages of business case development for a £2.7 million embankment scheme. People in the community know about it.

In Machynys, Llanelli, we’ve spent £1 million in the last 12 to 18 months on coastal repair work, and the same in Glynneath on damage caused by Storm Callum in 2018. We’ve also done some smaller work in Llansamlet.

Question: An NRW board report from September said you are not likely to meet your target to maintain 98% of flood risk assets in “high risk systems at target condition” this year – how will you prioritise which assets are fixed first?

Answer: We inspect all of our assets, and there is always something to fix. The fact it’s not at 100 per cent is not a problem.

Partly because of the winter floods, we’ve got a bit more repair work than normal. All the emergency stuff was done quickly. Some things take longer to repair, but it’s less serious.

Nothing collapsed in the winter floods but water did come over the top. That’s to do with the sheer quantity.

It’s very tempting to build higher and higher defences, but there are negative aspects to that. It does raise really challenging questions.

The flood defence dam in the hills above Pontarddulais, Swansea (pic supplied by Natural Resources Wales)

Question: There are three schemes in Swansea which seem to work with nature or the area’s topography: the Swansea Vale overflow area by the River Tawe, the dam in the hills above Pontarddulais, and the salt marsh reclamation at Cwm Ivy, North Gower. Do you think Wales will see more of these sorts of schemes, and the loss of land they entail?

Answer: There is a lot of interest in holding back water. The choice in Pontarddulais was building bigger defences in the town, where it’s highly constrained, or holding water back upstream where it’s less obtrusive.

Sometimes it’s about making space for water, but there is a knock-on as it does take up land.

In some places it’s really hard to move defences.

There’s also the aesthetics – you start putting walls in and people get less pleasure walking by rivers.

We worked closely with the National Trust at Cwm Ivy. Nature punched a hole through the seawall defence, and it (the land behind it) has become a valuable saltmarsh habitat again.

I know people have different views. The coastal walk (which used to traverse the seawall) was lovely, but we have to adapt. Some coastal walks may need to take a different path.

Question: Does planting trees upstream in river catchment areas always work as a way of slowing water flow, or is the jury still out?

Answer: It can make a difference in smaller localised flood events, particular if the catchment area is not already saturated, but not for really serious events.

From our perspective it’s part of what we can do. There is no simple solution to all of this.

Question: Most people grasp that a warming climate means a wetter climate and that sea levels are rising – how much is the sea level around Wales actually rising?

Answer: The UK Climate Change Projections report from the Met Office in 2018 has an awful lot of information.

They looked at capital cities in the UK. For Cardiff it was a 27cm to 1.13m sea level rise by 2100 based on a range of low to high carbon emissions.

There’s quite a bit of debate in the science community about high emissions, and some think it might be an under-estimate.

At the high end of it (sea level projection), that is a significant change.

Question: When are the next shoreline management plans for Wales going to be published, and what is your advice to anyone who is planning to buy a home by the sea?

Answer: Shoreline management plans are living documents and are going to be refreshed in the next 12 months.

They indicate a direction of travel and don’t set time frames.

But there’s no hiding from it. For places like Fairbourne (which sits on a low-lying sandbar in Gwynedd), and other locations, we can’t ignore the risk and it would be wrong to.

I think it’s important that people are aware of shoreline management plans.

My advice to people who are planning to buy a home by the sea is be aware.

I wouldn’t go as far to say don’t do it, but you need to be conscious of what the risks are.

Categories: Environment
Locations:
Authorities: Carmarthenshire County CouncilSwansea City Council

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