After the largely dry autumn and winter, in which no effective rainfall fell in many areas of southern England until January according to the Environment Agency, spring came early and turned the screw, especially the very dry April.
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| The dry River Lavant near West Dean |
March saw significant rainfall in northern England, but this didn't benefit the south. As soon as the rain stopped, river levels fell quickly. Early April was dry and very warm, the rest of the month was dry and cool with strong winds. We had no rain here in south Hampshire until the end of the month, 30th. This was the case in many parts of Britain. If it hadn't been for that day's rain, the monthly rainfall totals would have been even lower (see links to Met. Office monthly statistics and news releases below). The mild, early start to spring in March and abundant sunshine meant plants grew quickly, as did the rate of evaporation. By the last week of April, soils were bone dry and cracking and patches of brown grass were appearing. This brought an end to groundwater recharge, which had been inadequate during the crucial winter season anyway. River levels, including normally more stable flowing chalk streams fell everywhere. In most parts of the UK, gauged flows were either below normal or at the very low end of normal as if it was late summer (see links to relevant Environment Agency and CEH reports). In eastern and southern England, demand for water increased sharply as farmers were forced to begin irrigating crops much earlier than they'd usually expect. The situation across the English Channel was much the same, or even more entrenched, according to Eaufrance (see links).
According to the Met. Office, the monthly total for the UK in April was 47% of the long term average (1981-2010). The total up to 19th April was just 26%. The best case was Scotland, with 71%.
May began with the customary cool wet / showery Mayday public holiday. I went to Emsworth and looked round the Art Trail. The rain was mainly showery and confined to about a couple of hours during the middle of the day, with sunshine between the showers. After so much dry and preferring cooler / mixed weather to clear skies and relentless sunshine, I took real pleasure in the lull as I sketched around the harbour.
Bank hols over, normal service resumed, with high pressure setting in yet again, though this time, it was to the north of the British Isles, meaning that the warmest and driest weather was in northern Britain. For much of May, we were in Scotland. Being cool and breezy back home, the warm, generally very sunny weather in Edinburgh caught me out (9-11th May). The soil was at least as dry as it was back home and the grass in Holyrood Park was looking very brown. As I looked down onto the paths above Salisbury Crags, they reminded me of a network of dry rivers in a desert. My 45 litre rucksack was bursting at the seams partly as I was having to carry my layers of clothing rather than wear them. From Edinburgh, I moved on to Stirling (11-13th May). There, I visited the River Forth: Stirling Bridge and the view of the very sinuous river from the Wallace Monument. As noted in 7Squared Goes Forth it was very tidal. On the Friday afternoon, I chanced upon some shortlived tidal turbulence as the flood tide rushed in at Stirling Bridge on the Friday afternoon. While I was at the top of the Monument, though, it was about low tide and the river in the nearer distance shallower than paddling depth, with dry shoals of gravel exposed. Not knowing the area, I couldn't tell how much of this was tidal and how much due to low fluvial flow, but the burns I glimpsed in the Scottish Central Belt all looked fairly low.
Another wet interlude began on 13th May as I left Stirling, meeting up with my Cycling Man for a fortnight in Perthshire, based in a cottage on the northeastern shore of Loch Tay. The weather that fortnight was more mixed, with rain over both weekends - I watched the latter part of the Caledonian Etape in Glen Lyon stood under golfing brolly kindly lent to me by one of the marshals. It was generally, though very warm, especially during the second week. The last two days in the mid-twenties (celcius) and warmer than back home. It felt uncomfortable, and more so than the same temperature would do back home. I put that down to the mountain-glen topography, higher humidity and the notorious midges. The latter weren't as bad as I'd dreaded they might be. Some years / some areas they can be out and biting in mid-May and we both have very sensitive skin. Though we were lucky this time, it felt as if they were on the cusp and when the time came to head home (27th May), there was a real feeling that we were getting out just in time.
The main issue was, in common with so many otherwise comfortable / well designed buildings around the the UK, the cottage wasn't built for comfort in hot weather. All along the main wall, large windows and doors out to the decking, making for great views along Loch Tay. The southwesterly aspect and long light evenings in the north meant that the sun streamed in from 12 noon until it dropped behind the hill at around 7.30pm. Though pulling the curtains cut down the light and the glare, the heat built up in the building, clearly not insulated against the heat. Luckily back home our main room is relatively cool.
North of the Border in Perthshire, meanwhile, I thought the Loch level at Kenmore (the outflow of Loch Tay) looked low, with tree roots exposed high and dry on the shore - see Perthshire - Loch Tay and Around and the Tay subdued - see The River Tay - Perth and Dunkeld. I wondered if canoeists and white water rafters heading to the Grandtully rapids (below Aberfeldy) might have been disappointed. I wondered how much there would be to see at the Falls of Dochart (the Tay by another name above the head of Loch Tay) at Killin and on the tributaries. The Tummel below the Pitlochry dam certainly looked lower than it had been last year. The Falls of Dochart were probably down to their late summer level, nonetheless, I was pleased that there still seemed to be plenty of water coming over the falls to enjoy and sketch. I also sketched waterfalls above Fortingall in Glen Lyon. The River Garry in the gorge below Killiecrankie looked low but reasonable and there was still water to see at The Soldier's Leap. As we learned at the new Pitlochry dam visitor centre and exploring around the Lawers Dam between Glen Lyon and Loch Tay, the regime throughout the highland River Tay is heavily influenced by hydropower. There is the Loch Tummel scheme above Pitlochry and the Breadalbane scheme in the Loch Tay-Glen Lyon area.
The reservoir above the Lawers Dam was almost empty, though one of the key things with these schemes is the network of aqueducts and pipelines which enable water to be transferred between different catchments, eg from Loch Garry to Loch Ericht. See:
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| A brief May Day respite from the high pressure, Emsworth, 1st May |
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| Dry paths above Salisbury Crag, Edinburgh, 11th May |
Bank hols over, normal service resumed, with high pressure setting in yet again, though this time, it was to the north of the British Isles, meaning that the warmest and driest weather was in northern Britain. For much of May, we were in Scotland. Being cool and breezy back home, the warm, generally very sunny weather in Edinburgh caught me out (9-11th May). The soil was at least as dry as it was back home and the grass in Holyrood Park was looking very brown. As I looked down onto the paths above Salisbury Crags, they reminded me of a network of dry rivers in a desert. My 45 litre rucksack was bursting at the seams partly as I was having to carry my layers of clothing rather than wear them. From Edinburgh, I moved on to Stirling (11-13th May). There, I visited the River Forth: Stirling Bridge and the view of the very sinuous river from the Wallace Monument. As noted in 7Squared Goes Forth it was very tidal. On the Friday afternoon, I chanced upon some shortlived tidal turbulence as the flood tide rushed in at Stirling Bridge on the Friday afternoon. While I was at the top of the Monument, though, it was about low tide and the river in the nearer distance shallower than paddling depth, with dry shoals of gravel exposed. Not knowing the area, I couldn't tell how much of this was tidal and how much due to low fluvial flow, but the burns I glimpsed in the Scottish Central Belt all looked fairly low.
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| The River Forth from Wallace Monument, Stirling. "Exceptionally Low" in May |
The main issue was, in common with so many otherwise comfortable / well designed buildings around the the UK, the cottage wasn't built for comfort in hot weather. All along the main wall, large windows and doors out to the decking, making for great views along Loch Tay. The southwesterly aspect and long light evenings in the north meant that the sun streamed in from 12 noon until it dropped behind the hill at around 7.30pm. Though pulling the curtains cut down the light and the glare, the heat built up in the building, clearly not insulated against the heat. Luckily back home our main room is relatively cool.
Despite all the other stuff going at the time, the dryness caught the media's notice in mid-May, reflecting farmers' concerns about crop yields about the lack of rainfall and its potential impact on crops, especially cereal crops and the apple harvest. In the printed edition of The Guardian - page 11, 13th May, the poster river here was the upper River Eden at
Appleby-in-Westmorland. The photos contrasted its healthy during the Appleby (gypsy / traveller)
horse fair in early June 2015 with the trickling flow this spring. When I looked at the river level here (EA - Rivers and Sea Levels), 13th May, it was just 9cm deep (low end normal range 25cm). At Carlisle (Sheepmount) it was down to 0.53m (low normal 0.65m). There was some pick up here after the rain on 13th, 14th May, the level rising about 20cm at both sites, then it quickly dropped again. Usually, its its notorious floods which make the headlines, but it is a notoriously
flashy river with a roller coaster regime, the full flow range being from about 5 - 1700 cumecs (cubic metres per second).
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| Loch Tay, Kenmore, 17th May |
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| Lawers Dam hydropower reservoir, Perthshire, 26th May |
The Met. Office say that it was the second warmest May in the UK in a data series beginning in 1910, the first being May 2011. It was the warmest on record in the Central England Temperature series which began in 1659; and the warmest on record in Wales and Northern Ireland (Met Office, 2nd June). The May rainfall for the England was about average (Met. Office 1981-2010 average). In southern and eastern England it was above average (130% in some areas), mainly falling during the second half of the month, the 17th being particularly wet, apparently. As usual in late spring, though, this was ineffective in recharging aquifers or mitigating the rainfall deficit which has built up since last summer. because of the high rate of evapo-transpiration in warm weather and plant growth at full pelt. In Scotland, monthly rainfall was only 68% of average. In most parts of the UK, the rainfall deficit since last July, was at least 10% at the end of May. Soils dried out in most areas.
The EA and CEH's river flow maps for index rivers in England and the UK respectively show most rivers running below the norm expected during April and May (record lengths vary at different gauges, but all have data going back at least 40 years).. Particularly in northern and western areas, the hydrographs traced well below the line (long term average) during April and May. Many rivers were down to less than half. Six rivers in northern Britain were ranked as exceptionally low in May (red on the maps): the Tyne at Bywell (just 30% LTA). The other five were north of the border, confirming my impressions on holiday. They Tay was down to 40%; both the Spey and the Forth hit new lows (mean daily flow rates). 18 UK rivers around the UK were notably low (orange), including the Severn (Bewdley, down to 39%), a river in high demand for water abstraction; the Dorset Stour; the Great Stour in Kent; and the Salisbury Avon. The Itchen, a chalkstream was among those ranked below normal. The hydrograph for the Highbrook and Allbrook gauge has traced below the (LTA) line since last October. The more flashy (responsive) rivers in parts in SE England seemed to benefit from the rain later in May, eg the Mole and the Medway. The river flow map for July 2016 - end May 2017 reflects the rainfall deficit accrued since last summer throughout the UK, with 9 rivers ranked as exceptionally low, including the Spey and the Dart. 19 were notably low including the Severn, the Welsh Dee, the Medway, the Great Stour the English Tyne, the Tay and the Tweed. The Thames was below normal. The Itchen was among only 8 on the map ranked in the normal range (green).
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| River Mole, The Stepping Stones beneath Box Hill, 7th June |
Rainfall during the first week of June (5th, 6th) brought a temporary pick up in flows on responsive rivers in SE and NW England. The Mole was flowing well when I saw it beneath Box Hill on the 7th, and across the Sussex watershed, the Arun at Pulborough showed a similar rise superimposed on its tidal flow. After running low in May, the Eden at Appleby and Carlisle returned to its normal flow range, though the Sheepmount gauge seems to have been playing up and giving spurious readings lately (EA River and Sea Levels). The Severn (Bewdley) responded more slowly. By mid-June, though, levels were dropping again. My energy and mood seemed to reflect these trends, independently though sympathetically: early June, energised after our Scottish trip; relishing the fast changing skies over Emsworth on the 6th; then dropping again during the second week of June as temperatures rose.
Looking ahead to the summer during what's so far been a very warm, generally dry year, a trivial point I know compared to most things going on in the wider world, but when talking about hot weather, it would help my flow and wellbeing if weather and news people could acknowledge that hot weather isn't for everyone. I.e, less of the "we are enjoying a heat wave", "the nation is enjoying temperatures in excess of 30 degrees" and "the people have spoken and they like it hot".
Links / References
Met Office News releases / blog:
Dry weather in April
April 2017 UK weather statistics (temperatures, rainfall, sunshine hours) -
Long term average 1981 - 2010, records from 1910.
Spring 2017 UK Weather Statistics
http://www.metoffice.gov.uk/news/releases/2017/warm-and-dry-may-to-round-off-spring
CEH monthly hydrological summaries for the UK:
CEH National River Flow Archive (gauged flows and hydrographs):
Environment Agency - weekly and monthly Water Situation reports for England and English regions including soil moisture, river flows, groundwater levels, hydrographs at various river gauges and groundwater wells.
Environment Agency - River and Sea levels around England for the past few days: https://flood-warning-information.service.gov.uk/river-and-sea-levels
Ditto Wales
SEPA - ditto Scotland
Eaufrance - monthly summaries for France
Vigicrues - gauged river levels and flows on French rivers
My blogs:
My artwork - http://artywater.blogspot.co.uk/2017/
