We’re going to be taking down the rain-out shelters in the Eden catchment in reading week, w/c 15 October 2018. Student volunteers sought to lend a hand, do something different and see some new places on the Lomond ridge above Falkland and at a farm near Dairsie, Fife. Students see email from Jenny Eades, or please contact me direct.
We’re monitoring water levels on the upper River Feshie, and at two other sites lower downstream (and on some of the headwater tributaries too)! This is all nested within the catchment of SEPA’s gauge at Feshie Bridge, and will help provide a better understanding of the hydrology of this dynamic catchment.
Today, we have a hydrograph which has steepened as it travelled downstream, leading to a 400+mm rise at SEPA’s Feshie Bridge gauging station in 30 minutes. In the upper catchment the rainfall has been steady, rarely exceeding 4 mm/hr, leading to a fairly gradual rise.
We’ve seen the opposite situation earlier in the summer: steep hydrographs in the headwaters attenuating downstream, notably a 150 mm rise in 3 minutes which was barely noticeable once it made its way downstream to Feshie Bridge. I’m going to say nothing today about causes, but just mention in-channel friction, rainfall patterns, and gradients. Some hydrographs below to illustrate. More evidence to gather first.
Data at the upper Feshie (Eidart confluence) site are recorded every minute, providing a high level of detail, which is useful when examining rapid rises. Hydrologists working in the river, and walkers crossing the river on foot (there are no bridges on the upper river) need to be aware of the risk of rapid rises like these. Sometimes we hear stories of absolute walls of water – potentially lethal.
The exams are all finished now, so what better than a field visit to revisit some of the key themes of the semester just passed? More so when there’s the offer of a guided tour from Scottish & Southern Energy’s biologist Dr Alasdair Stephen, and a shining yellow thing in the sky all day long!
The focus for our day was the River Garry, which has been dry for most of the past 60 years thanks to a diversion of the upper river to supply water to Loch Errochty, for renewable power generation at Errochty Power station. SSE concluded an agreement with the Scottish Environment Protection Agency (SEPA) and the Tay District Salmon Fishery Board to allow the new provision of environmental flows, commencing in autumn 2017. We spent some time in class talking about in-stream habitat and ecosystems: the role of water depths, velocities and wetted perimeter. The works allow SSE to put the demands of the Water Framework Directive into practice.
But the trip soon revealed that a lot more was required than ‘just’ hydraulic and ecological modelling. Our discussion turned to questions of scientific evidence, stakeholder benefits, partnership working, people as much as policy, and balancing acts – how best to protect the local freshwater environment without causing unnecessary losses of generation water?
A few photos here give a flavour of the day. Many thanks, Alasdair, for sharing your knowledge, many experiences and insights.
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.
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…?
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.
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?
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.
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.
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!
Many thanks to Sam and Ivan for invaluable help on the day.
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 🙂
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.
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.
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.
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.