Scotland floods: From A83 to swamped crops, what to learn?

The deluge raised many questions. What can we learn from the past week about how to protect ourselves from flood risk? And, are rains like these likely to become more common as a result of climate change?

First up, how does this rain compare with previous floods and storms?

Hydrometry river measurements at the weekend in the river Tay were described, on Twitter, as “mindblowing”. They measured 1600 tonnes of water every second on the River Tay at Ballathie.

However, river levels did not exceed historic recorded highs – for instance, the River Spey at Aberlour, at just over, did not exceed the 3.4 metres recorded in 2014, and the Tay, at Ballathie, at just over 6 metres, didn’t top the over 7 metres recorded at Ballathie in 1993.

High water levels of the River Dulnain at Carrbridge near Aviemore. Jane Barlow/PA

Nor has it caused anything like the physical damage of the Muckle Spate of Strathspey, one of the most catastrophic floods in UK history, which took place in 1829, and saw bridges washed away and  600 people left homeless.

Dr Mark Wilkinson, a senior research scientist in catchment management at the James Hutton Institute, described it as like a “large wet winter event”, but noted that it has been severe in some parts of Scotland.

READ MORE: Aviemore floods: 'Danger to life' warning as flood waters rise

Are rainfall and flooding increasing?

Yes, according to the UK Climate Change Committee’s 2022 report, Is Scotland Climate Ready? “Over the last 30 years" it states," average temperature in Scotland has risen by 0.5⁰C, Scottish winters have become 5% wetter, and sea level around the Scottish coast has increased by up to 3cm each decade. ”

In a blog for the James Hutton Institute, Dr Mark Wilkinson, notes  that floods come in many forms: “flooding caused by rivers, when they burst their banks; surface water flooding, for example, where there is intense rainfall on cities; groundwater flooding, where water seeps up from the ground, causing the water tables to fill; and coastal flooding, for example, caused by storm surges.”

“Many of those types of flooding,” he says, “are increasing for three main reasons: climate change; where we put new houses and developments; and how we manage the land within our catchments.”

What was the storm's impact on agriculture?

Earlier this week NFU Scotland President Martin Kennedy described the level of flooding seen in some parts of Scotland as “exceptional”.

“Reports and social media coverage of the extensive flooding, landslips and road closures," he said, "significant areas of grassland, arable ground and high-value crops such as potatoes, broccoli and turnips under water and the loss of fodder and bedding to flooding are clear indicators of the unprecedented scale of damage in some parts.

Mr Kennedy called on the Scottish Government to consider giving short-term support to the recovery process and noted that too often when it comes to risk, the farming industry "is left carrying the can". "While some losses may be insurable, many will not, and it is likely that farmers will be left with a bill for millions when the mop-up is finally completed.”

Some businesses, NFU Scotland said, have incurred substantial losses due to flooding, including some that have lost livestock. For instance, a field of swedes in Perthshire destined for supermarket was underwater for days, costing an estimated  £350,000. Over social media, footage was shared of bales of silage swept down the river at Inverary, each bale lost worth around £25.

Mr Kennedy also shared footage this week of high-quality land that had been flooded as a result of a destroyed section of flood bank which he attributed to beaver damage.

But aren’t beavers supposed to help protect against flooding?

It depends on where and how you look at it. Whilst it does seem this particular damage was caused by beavers, there is research to suggest that beavers can also be beneficial.

One paper by CREW, the Centre for Expertise for Waters, states: “Much evidence has shown that beaver dams can attenuate high flows, by decreasing the magnitude of flood peaks downstream of beaver dams and increasing their lagtime. In the UK, relevant research has been conducted both in England and Scotland with evidence coming from agricultural and forested environments.”

Is damage to crops and agriculture likely to increase with climate change?

Yes, according to the UK Climate Change Committee’s  (CCC) report ‘Is Scotland Climate Ready?’. “A significant proportion of agricultural land in Scotland,” it says, “has been impacted by fluvial flooding in recent years, with the area of best quality agricultural land at risk from fluvial flooding in Scotland currently projected to increase by 26% by the 2050s.”

READ MORE: Floods, drought, ferry disruptions. Highland climate change mapped

What about roads and infrastructure?

Trains were cancelled. People were advised to stay at home. Some key roads were entirely blocked by the flood and rain damage. A 600-tonne landslide, for instance, blocked the A816 at the Bealach between Ardfern and Lochgilphead – where it is now set to be closed for a month as the council clears the mass of debris.

According to BEAR Scotland, on Saturday, there were seven identified landslips on the A83, including several at the Rest and Be Thankful – causing road closures. Ten people had to be airlifted from their vehicles.

The Rest and Be Thankful blockage, however, was nothing new, and campaigners have long been calling for improvement. The infamous stretch of road passes through Glen Croe and is regularly closed by falling rocks and debris.

Is infrastructure damage likely to get worse?

Yes, according to the CCC report: “More frequent flooding and increased coastal erosion will cause damage to infrastructure services, including energy, transport, water and Information and Communication Technologies (ICT). For example, over 800 km of railway is already exposed to significant surface water flooding risk in Scotland. This could increase by over 60% by 2100 under a high-end global warming scenario. Recent storms across Scotland have also highlighted the vulnerability of infrastructure systems to extreme weather and the increasing exposure of our society to weather-related failures of the electricity system.”

What is being done about it?

Earlier this year, Transport Scotland unveiled a for construction of a debris shelter, a kind of open-sided tunnel, as a solution to the problems on the A83 at the Rest and Be Thankful.

Other solutions are also already being trialled. For instance, Forestry and Land Scotland and Transport Scotland have been working together on the The Rest and Be Thankful woodland creation project, tree-planting on the steep flanks of Ben Luibhean, Glen Croe.

Previous landslide at Rest and Be Thankful

As the woodland matures it should help prevent land slippage. A trial of the use of drones to plant tree seeds over the hillside earlier this year saw 20kg of native tree seeds dispersed at the A83 over a two-day period.

What about homes and property?

It’s hard yet to estimate the degree of damage to homes and private property, but we know it has happened. Houses in Perth, around Barossa Place, had their basement areas flooded after Perth Council failed to close a North Inch floodgate in time. People in Ballater, Aberdeenshire, were advised to leave their houses as the Dee threatened to burst its banks. The River Tay at Aberfeldy broke its banks before owners had a chance to remove their caravans. Oban’s Lochavullin industrial park, frequently a site of intense flooding, was submerged.

The flooded Dell sports field in Kingussie near Aviemore

Is this likely to get worse in the coming years?

The CCC report notes that “significant increases in the severity and frequency of flooding of homes and businesses are expected.”

SEPA also states that there are “around 284,000 homes, businesses and services at risk of flooding in Scotland, and that number is only increasing”.

However, Scottish Planning Policy does not, in general, permit building in areas in which ‘the flood risk exceeds the 200-year return period’ - and states that the planning system should promote flood avoidance by locating development away from functional flood plains.

READ MORE: Climate change or not, floods are reminder the weather is bigger

What were the key areas hit by floods?

The catchments of the River Tay and the River Spey, as well as Argyll, where numerous landslides took place, some blocking off roads, as well as Argyll, where roads were blocked and parts of Oban flooded.

Many of these areas are already known to be problematic. SEPA’s flood risk management plan, published in 2021, for the Tay district states, “All up, in this part of Scotland, there is a risk of river, surface water and coastal flooding and the expected annual cost of flooding is around £11.4 million.”

It also notes that there are around 9,000 homes and businesses at risk from flooding, and “this may increase to 13,000 homes and businesses by the 2080s due to climate change.” The Tay is the longest river in Scotland and has the largest catchment area. More water flows through the River Tay than any other river in the United Kingdom.

SEPA’s flood management plan for Findhorn, Nairn and Speyside Local Plan District estimates that there are around 7,300 homes and businesses at risk from flooding, and this may increase to 9,900 homes and businesses by the 2080s due to climate change.

The flood risk management plan for Highland and Argyll states: “Oban is located on the west coast of Scotland and is within the Argyll and Bute Council area. The main source of flooding in Oban is river flooding from the Black Lynn Burn, however, there is also a risk of coastal and surface water flooding.”

It notes that there are approximately 1,200 people and 940 homes and businesses currently at risk from flooding and that this is likely to increase to 1,200 homes and businesses by 2080 due to climate change.

Are there patterns around Scotland’s flooding?

Whilst there are some places that are more likely to flood, as Dr Wilkinson points out, “no two floods are alike”. “When we see these floods in Scotland they seem to affect different places with different severity. Storm Frank, in 2015,  for instance, affected the northeast of Scotland quite severely – places like the Dee for example. This current event affected other communities across Scotland more.”

Floods in Ballater during Storm Frank

The takeaway warning, he says, is:  “Rainfall can fall in different amounts anywhere, though there are some areas that are certainly more prone to flooding and have more frequent flood events.”

“Floods,” he says, “are becoming more frequent. But it’s not our only weather-related risk. We were talking about water scarcity only a few months ago.”

What can we do to handle flooding and prevent damage when rains come?

There are a few approaches. One, says Dr Wilkinson, is what’s called “grey engineering” - the classic flood walls, embankments, tidal barriers and engineered structures. Another is what’s described as “natural flood management”. This involves, for example, tree-planting, soil management and pond and wetland creation.

“For lowland areas and farming a key thing that can be done is that good soil management can help water to infiltrate. The use of trees in strategic areas can help. It even comes down to what we do at home. We are all part of the solution. Allowing water to infiltrate our gardens helps slow down the progression of water movement through the catchment as sealed surfaces like paving allow water to flow over. It's the idea of slowing, storing, and attenuating water runoff within a catchment."

“Yes, we need grey infrastructure in certain places. But it's a matter of funding and also what the green solutions do is they complement the grey and in places maybe they can help be part of solving the problem. We need every trick in the tool kit.”

Many of these nature solutions, he says, also have co-benefits. “They can help improve biodiversity, help to alleviate water scarcity, store carbon and improve water quality issues.”

Can we see examples in Scotland of nature reducing flood risk?

Earlier this week Pete Cairns Executive Director of Scotland: the Big Picture tweeted footage of how a rewilding project on the Feshie had helped reduce flood risk, by “allowing the river to access its floodplain".

Flood risk is reduced when rivers can access their floodplain. Here, the River Feshie in the Cairngorms, is ‘allowed’ to flow into an alder woodland, where it branches off into more channels, thus distributing water across the land, and slowing the flow. #riverwoods #northwoods pic.twitter.com/198fCt2Q1b

— Peter Cairns (@PCairnsPhoto) October 7, 2023

Cairns explains: “We have historically straightened and constrained rivers behind bunds and concrete walls. Allowing rivers to meander naturally and to access their floodplains, where woodland and grasslands can absorb water and slow the flow, is a natural, cost-effective way of reducing flood risk.”

Do we know if this particular rainstorm was caused by climate change?

No, we don’t - yet. The figures have not been crunched by experts and may never be. Some storms that have been analysed, like Storm Daniel which burst two dams inn in Libya earlier this year, have been found to have been made vastly more likely because of climate change (fifty times more likely), others, like that which caused huge damage in Emilia Romagna were found not to be linked to climate change.

However, studies do suggest that overall, globally, rainfall and flooding is increasing due to climate change. An attribution map produced by Carhon Brief showed that of 126 rainfall or flooding events, 71 (56%)" found human activity had made the event more likely or more severe". 

A 2018 study by Oxford University found that "climate change increases the probability of heavy rains in Northern England/Southern Scotland like those of storm Desmond".