Remembering the Great Tay Flood of January 1993

25 years ago, on 17 January 1993, a peak river flow of 2268 m3/s was recorded at Ballathie gauging station on the River Tay – the highest rate ever recorded in the UK.  At the time, I had only just started work for the National River Flow Archive at the NERC Institute of Hydrology.  The flood left hundreds of people with devastated homes and many lasting impacts: the memory is perhaps best forgotten for many of them.  For me, it was a key moment at the start of a hydrological career in Scotland, and there’s been no lack of interesting projects to investigate since.

Reflecting on the Great Tay Flood, it’s worth taking a moment to think about how much has changed since then.  Many of these changes may be partly attributable to that fateful event in Perthshire: it changed how we thought about flood risk in Scotland at least.  Here are some quick personal reflections:

Climate change was much more of a contentious issue back then – could human agency really be changing the climate?  There was a sense that this was a flood (reckoned to be the biggest in almost 200 years) that shouldn’t have happened: something must have gone wrong to cause such a disaster.  Some looked to climate change as “the reason”.  I remain uncomfortable with the idea of attributing a single large flood solely to climate change, but I think the vast majority of hydrologists would see it as being of critical importance to flood risk assessment in general.  It’s one of the key hydrological challenges for the future.

Sodden house contents after the flood

Flood forecasting and warning were in their infancy then.  Certainly, the hydrologists of the day were using all the information at their disposal; it was clear to them that something very big was about to happen, and that information was shared with the authorities who needed the best information available.  Telemetry monitoring systems, the science behind flood forecasting and the methods of issuing warning messages and preparing recipients have been transformed in the years since – see the Scottish Flood Forecasting Service. and Scottish Flood Forum.  I’m not sure if community resilience had entered many people’s vocabularies back then…?

Dalguise
Washed-out railway embankment at Dalguise in the Tay valley

Perth got its flood defences, completed in 2001, at a cost of £25 million – the most costly scheme in Scotland at the time.  At 8km long, the design allowed for subsequent raising if the need were to arise: a recognition of the uncertainty of risk estimation and the possible effects of climate change.  The defences incorporated more than 80 gates, to address local needs for access, and relying for their operation on the growing capabilities of flood warning.  The scheme provides structural protection for many hundreds of homes and businesses, and a good deal of peace of mind for those at risk.

Perth flood defences under construction, Tay Street

It’s worth thinking about the role played by the flood marks on Smeaton’s Bridge.  The marks showed that 1993 was the highest flood since the bridge was built in the 1770s – excluding the 1814 ‘ice jam’ flood.  And that was an outlier – we don’t get ice jam floods any more: nobody was arguing that we should allow for that scenario in future.  So the historic record provided a context for the flood: it gave some certainty that this flood really was something unprecedented.

Also since 1993, legislation has seen the responsibilities for flood risk management overhauled, most recently in the 2009 Flood Risk Management (Scotland) Act, with the roles of local authorities and SEPA (formed in 1996) in particular clarified, extended and better coordinated.

What else has changed or happened? Scottish devolution, the economic downturn of 2008, ubiquitous smartphones!  These are just a few thoughts as we pass this anniversary.  Maybe you’d like to share your thoughts?

Reaching out in NE Fife – drought risk, climate change, agriculture and YOU!

Drought Risk and You – talking about drought, climate change and farming in Freuchie, Saturday 20th January 2018.

Registration link here.

Programme available here: Jan 2018 Eden DRY event v4

Scotland is considered by many as a wet country but over the past years we have seen some prolonged dry periods – for example, 2003 in Tayside, 2008 in the Hebrides and 2010 in SW Scotland. 2017 saw a dry spring in central Scotland.

The DRY project, funded by UK Research Councils, is investigating drought and water scarcity in the Eden catchment alongside 6 other river basins elsewhere around Great Britain. We are collecting digital narratives from local people, while also undertaking experimental crop and grassland research, and computer-based hydrological modelling. We want to discuss with you:

  • What were the impacts of past droughts like 1976 and 1984 in Fife?
  • What could future drought look like in Fife?
  • What might the impacts of future droughts be on agriculture – on food and fodder crops?
  • How might grassland – a common land cover in lawns, golf courses and pasture – be affected?
  • What research is being undertaken in Fife and the UK to investigate these impacts?

Come and join an action-packed morning where we share some of the science that has been generated though the DRY Project. You have the opportunity to share your stories about past, present and future drought impacts and possible adaptations to drought and water scarcity in Fife and Scotland.

At this event, we aim to engage particularly with the agricultural sector and local people. Members of the research team are keen to capture your thoughts on the day in audio/video formats, with a view to sharing your experiences and insights as part of the wider project . Contributors from the DRY project team participating on the day will be:

  • Professor Lindsey McEwen (University of the West of England) – team leader, Drought Risk and You
  • Dr Ivan Grove (Harper Adams University) – Presenting results of crop research experiments at Harper Adams University. Drought experiments have been conducted on Wheat, Barley, Triticale, Durum Wheat, Quinoa,
    Perennial Rye Grass and Lucerne.
  • Dr Andrew Black (Dundee University) – local coordination for Eden (Fife) catchment, leading site visit to “rain-out” (drought simulation) grassland experimental site on the slopes of East Lomond.
  • Members of the digital storytelling team from the School of the Arts, English and Drama at Loughborough University.

To assist with the collection of digital stories, the organisers are interested to arrange opportunities to audio/video record your experiences and insights about drought risk in the Eden catchment. We’ll follow up all registrations with a follow-up email asking (without any obligation) if you would like to make yourself available for this.

Sometimes, environmental monitoring just has to be a team effort

Upgrading of the power supply required a field visit last Friday, in the interests of maintaining data completeness.  Fortunately, Wildland as site owners have the logistical capabilities to deliver results.

SBS500 recording rain gauge

Visiting during wintry conditions allows processes to be observed at first hand: the icing on the equipment will surely affect recorded precipitation amounts when melt occurs (24.4 mm recorded over 3 hours on Sunday 17th); it was also an opportunity to clear the sensors.  Impressively, the R M Young wind speed & direction sensor was still operating correctly!

When only serious logistics will do!

Many thanks to Sam and Ivan for invaluable help on the day.

Chilly for flow gauging

It was minus 10 C when our Eddleston field hydrometrist Boyd set off for his work this morning – but the work must go on!  Indeed some flow meters might not cope with such temperatures, but our Flow Tracker – and Boyd – seem able to cope with the conditions.  Low temperature gaugings let us keep check on ratings when ice/snow build-up may affect channel conditions and water levels.

Extreme conditions often produce the most memorable photos – so glad there was some added benefit arising from your determined efforts, Boyd!  I am happy to confirm it was very warm in my office this morning 🙂

Storm Caroline brings in the changes to Glen Feshie

Maximum wind speeds at the Wildland Mountain Observatory reached 70.5 mph this morning (31.49 m/s) as Storm Caroline brought high winds and property damage to many parts of northern Britain. Temperatures at 900 m OD fell from a balmy 7.0 C at 0130 GMT to -0.8 C three hours later, and down to -4.8 C at 2045 GMT.  This brought to an end 3+ days of continuous snowmelt from all elevations across the catchment: a 10 mm rainfall at high altitude caused a brief further rise in the river, followed by a fall to levels quickly below the snowmelt levels of the past few days.  Heavy snow is now forecast for all levels, so the river looks set to continue falling for some days.  Disdrometer data from Druim nam Bo show snowflake diameters in excess of 8 mm.

Feshie Bridge hydrograph 4-7 Dec 2017. Source: SEPA

Note for comparison: the Cairngorm AWS recorded a maximum gust speed in the order of 120 mph at an altitude of 1245 m OD.  The ridge location of the Druim nam Bo AWS may limit wind speeds there in comparison to the smoother, broader Cairngorm summit.

Uncovering the secrets of the environmental past – you can help!

Weather Rescue project is seeking volunteer citizen scientists to bring historic weather observations into the reach of digital science. Millions of meteorological observations are waiting for volunteers to enter them into digital format, and so make then accessible for climate research.  And of course where improvements in climate research take place, there’s scope to improve hydrological understanding too – not least extremes of wet and dry.  See the feature article and the link to the project here on BBC news.

Post your comments here if you’d like to share your efforts as part of a Dundee team effort.

Monitoring mountain precipitation – difficulties in practice

Power availability is the big challenge at 900 m elevation.  The Wildland mountain observatory on Druim nam Bo benefits from a 60 W solar panel and a wind turbine generator, with 220 Ah of battery capacity.

Ben Pickering’s disdrometer, pictured here in the foreground, needs 1 Amp of current, so sometimes there isn’t enough to go around (for long).  A low voltage disconnect (LVD) stops the power to the disdrometer when reserves get too low – leading to this icing-up spectacle on 19th November – while the weather station continues unabated.  Since then, conditions have improved, so hopefully laser radiation is once again analyzing the precipitation – solid and liquid – as it falls.  Latest data are here.

Big thaw at the weekend

After 10 days of continually freezing conditions at the Wildland mountain observatory on Druim nam Bo, warm air on Saturday brought a thaw to high altitudes – and significant melt.  Some 41.2 mm of snowmelt was recorded through the rain gauge.  The ground had been frozen and gradually climbed above zero – escaping from freezing some 16 hours after the air temperature.

Water level in the adjacent pond rose some 5 cm, soil moisture content rose from 2% to 18% – though the initially low value may be a reflection of freezing conditions.  The rise in pond level began 2 hours after thaw began to be recorded by the rain gauge.