Perth 15th May
We went to Perth on the first Monday or of our fortnight. It had been raining over the weekend, though the
rain was easing off by the time I got down to the Tay. It also felt milder and more humid. Strolled under the Smeaton's Bridge and through North Inch Park. Bridge built of red sandstone conglomerate,
with rounded pebbles. Also, dune or current bedding.
As
rivers go at the moment, this one looked as if it had healthy flow, even allowing for it being tidal, and apparently low tide, up to Smeaton's Bridge. A broad channel. Nonetheless it looked well down on
when we were here five years ago. The flow
generally was much more subdued, including the rapids underneath the bridge
arches.
More boulders exposed at base of the pillars and nearer the shore.
Everywhere very shallow. Upstream of the bridge, very reflective everywhere.
This is the longest river in Scotland and is the British number one in terms of volume of water
carried (flow rate in cubic metres per second). When it reaches Perth it is carrying more water than the Thames
and Severn combined and regularly outruns much larger rivers on the continent.
This is me standing by the flood marks carved into the
red sandstone of Smeaton's Bridge, taken five years ago.
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| Smeaton's Bridge floodmarks, May 2012 |
The highest recorded was 1814, marked by a
deep groove in the bridge. If remember rightly, Smeaton's Bridge was completed just three years earlier and, unlike others on the Tay at the time, it withstood the flood. The flood was made worse by blocks of ice piling up behind the bridge during a rapid thaw of snow. This was the same year as the last Frost Fair on the River Thames. The biggest flood in recent times was in January
1993, about 18" below it, the biggest flood of the last century here. It went on record as hitting a peak flow over 2000 cubic metres per second just upstream of Perth, at Ballathie. In early January 2016, following rainfall after successive winter storms from early December and most of all, Storm Henry, the flow peaked at over 1800 cubic metres per second (ref 1). These would be serious flows on the Seine and would have them worried in Paris. By 500 cumecs on the Thames, they have a serious flood situation on their hands, as February 2014 showed. During the stormy winter the before last, the peak flow was around 1800 cumecs, in early January 2016, the highest flow recorded on any river in the UK that winter. The peak flow reached 1000 cubic metres per second on at least seven occasions that winter (1).
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| Floodmarks 2017 |
Though there's no mark for anything in 2015/16, there's some striking, even alarming YouTube footage of the Tay, the Falls of Dochart and the Tummel at the Pitlochry Dam from this time. As far as I'm aware the flood defences held in Perth, though the videos here show it spilling into lower lying areas beneath them and some very exposed looking townhouses on the left back of the river near Smeaton's Bridge. The Pitlochry Dam and Falls of Dochart were transformed into massive waterfalls. Both looked well beyond the league of any British river, though this stormy winter was truly exceptional in terms of rainfall and run-off totals (1). True, property and infrastructure damage from these floods was much worse south of the Border that winter, but floods and weather events in Scotland tend to receive much less media coverage in the UK-wide media than in England and Wales, BBC included. It seems Scottish rivers can get away with high flood flows. It helps that the population density is lower, meaning less property "in the way", though the Central Belt, where Perth is, is built-up and heavily farmed.
When considering high, and low, flows on many Scottish Rivers, the Tay basin especially, we need to be mindful of the effects of hydropower schemes. More about them in another entry, but there has been hydropower in this basin since the 1930s and any floods before 1950, pre-date the construction of the Pitlochry Dam and smaller dams in the Tummel and Loch Tay and Glen Lyon (Breadalbane) area. All these schemes involve pipelines and aqueducts moving water between the tributary catchment. Ultimately it all ends up in the Tay, though at a slower rate than if the schemes didn't exist, thereby reducing peak flows.
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| Floodgate, North Inch Park |
The
flood defences were completed in 2001 Essentially walls along the roads
and big beefy floodgates bordering the park. The one pictured right is near the war memorials at the
southern end of North Inch Park. Seemingly another example of good, well designed flood defences: as well as being effective when needed, they enhance the area, treating the river as part of it during the quiet times, instead of being a barrier cutting it off from everyone (e.g. Keswick which was overtopped by the Storm Desmond flood anyway). They'd used the defences as a venue for art and sculpture, including the floodgate above and along the wall downstream of Smeaton's Bridge. Inscribed calligraphy along the wall,
including mention of a big flood in 1661, pre-dating Smeaton's Bridge.
References:
1.(1)
TJ Kirby et al, CEH, "The Winter Floods of 2015/16 in the UK - A
Review" (2016).
A selection from YouTube:
a) Perth, Storm Desmond, 5th December 2015,Queens' Bridge closed https://www.youtube.com/watch?v=0pkITlXJMLM
b) Perth, Storm Henry, 4th January 2016 https://www.youtube.com/watch?v=vYv_95fyu9k
c) Storm Frank and the Pitlochry Dam, 30th December 2015:
d) The Falls of Dochart, Killin, 30th December 2015:
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Dunkeld - 22nd May - Reflective Tay and gentle rain
A
relatively easy, unwinding day for my Cycling Man after yesterday. Weather
mainly cloudy, a bit wet at times, though mainly later in the day as we came
back. Brighter for a time during the afternoon.
Went
to Dunkeld and walked along the Tay, the left (east) bank from the cathedral
area, taking the riverside path beneath the arboretum with the big redwoods
etc. Parked at car park round the back, after crossing Dunkeld bridge. While we were in town, we saw at least one cyclist and a couple of cars / SUVs carrying bicycles with the give-away brag-factor Etape numbers.
Though
only small, if any changes in the SEPA water levels, I thought the rain had
brought the flow of the Tay (and Tummel) where crossed on A9 below Pitlochry.
At Dunkeld, where the Tay was wider, it seemed to be going well. I'd say at
least as good as when I was here at the end of April last year, though it was
fairly low then. Some of the anglers waded in above their thighs. A couple
fishing from a boat. Flipside of the rain was it had brought the bugs out,
though thankfully still not too many biting midges. Worry about later this week,
when forecast to turn warmer. The Tay here seemingly a definite current, yet reflective,
though some intrusive noise from A9, running close by on the far side. Took
quite a few photos and some very quick sketches of the restful, reflected
greenery on the far side of the water. Rained for a time, though it was
relatively light and, beneath the trees mostly sheltered. The seat we sat on
for our early lunch was dry. Ripple patterns from the rain drops. A broad
pebble bank on the upstream side of the arboretum.
After
our lunch, strolled down to the bridge and across it to Birnam. River just
below bridge, broad and shallow, glowing around an islet, gradient of river bed
briefly steeper. Rapids here running well. Strolled along the right bank in the
Birnam Wood, just beyond the famous Birnam Oak. Took pictures of inscribed
trees and "eyes" in the bark of trees nearer the river. Then headed
back, and up the A9 to the southern end of Pitlochry, stopping along the way for a guided tour, complete with a tasting session, at the Edradour whisky distillery.
