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Whaley Bridge Update II

August 5, 2019

By Paul Homewood 


The collapsed dam

The situation at Whaley Bridge remains critical, although the heavy rain forecast yesterday does not seem to have arrived..


Meanwhile some data updates, which shine some light on what really happened.

I have been spending the last few days trying to get rainfall data out of the Met Office, who have proved to be their usual inefficient selves, and even tried to charge me for what should be fully available on their website anyway. (They are after supposed to be a public service!)

As usual, I have now had to resort to FOI.

However there is a database run by a company called Shoothill, which lists river levels and rainfall stats at river gauges all over the country:




There are two gauges very close to Whaley Bridge, and both highly relevant. Langley Bottom is about six miles south, and sits below the same Buxton hills which feed the River Goyt. The second is at Chapel en le Frith, a couple of miles to the east of Whaley Bridge:


Longley Chapel
July 25 0 0
26 2.4 0.8
27 17.4 15.8
28 60.8 56.4
29 6.8 3.8
30 15.6 16.6
31 45.4 47.8
TOTAL 148.4 141.2


There was about two inches of rain on the Sunday, the 28th, but this was compounded by another couple of inches on the Wednesday.


As we have seen, two inches a day is not an uncommon event anywhere in England, and particularly in Pennine areas.

The best long term record we have in the area is at Buxton, itself about five miles from Whaley Bridge. (It is Buxton where I am trying to get the data from the Met Office for!)

As we can see from the KNMI database below, there have been 90 days with rainfall over 40mm since 1920, effectively one a year on average.



By far the worst day was 15th July 1973, when 87.5mm fell. Buxton was by no means the only place affected that month:





Obviously the coincidence of two heavy rainfall days around Whaley Bridge last week turned a regular event into an exceptional one, but even then not that unusual.

Over the 7-day period leading up to the dam failure, Longley Bottom received 148mm of rain. Again using the Buxton database, we can track other similar events:


There have been seventeen years where 7-day rainfall exceeded 120mm. The worst was in October 1998. In the week leading up to the 28th, 216mm fell, including two days with 58mm, one of 34mm and another of 25mm.

One of the issues with the dam last week was that it was apparently already nearly full before the rains fell. I am not in the least surprised as our dams on the Yorkshire side have been full for months as well.

But it does beg the question, why are these dams kept at maximum levels, especially when the Met Office has given ample warning of heavy rains? After all, part of the function of dams is to regulate water flow downstream. This can involve storing water for when needed in drought. But it also means reducing flows at times of heavy rainfall by storing water in the dams.

Certainly, if the dam levels had been kept sensibly below maximum capacity at Toddbrook before last week’s rains fell, the problems with the spillway would not have occurred. But also downstream areas would have been protected from flooding as well.


As for the dam itself, even the BBC are now questioning whether the spillway itself was at fault:

Heavy rainfall caused water levels in the reservoir to rise and start flowing over the auxiliary – or emergency – spillway.

The structure failed and was partly eroded away by water flowing over it.

Alan Warren, chairman of the British Dam Society, said the cause was unclear.

"We don’t know whether the concrete was inadequate or whether there was some problem underneath those concrete slabs which means the slabs fell into a void that had been forming underneath," he said.

"Maybe the joints in the slabs weren’t properly sealed, and water was getting in through the joints."

Mr Coackley said photos suggested water had washed away soil beneath the slabs but the clay core was still intact.

"That’s why the dam is still secure there at this stage," he said. 



The BBC has now started to ask some serious questions about the maintenance of the dam:


Photographs showing weeds growing on Whaley Bridge’s dam have prompted some to question whether the spillway was maintained properly.

One resident, who lives near the dam, sent the BBC photos – taken in 2016 and 2017 – which he said showed concrete with "vegetation growing out of it".

Hundreds of people were evacuated from the town last week when heavy rain damaged the auxiliary spillway.

It is designed to channel overflowing water away from the reservoir.

The BBC has asked several experts to analyse the pictures.

Roger Meredith was a construction engineer at Tarbela dam in Pakistan. This is an earth-filled dam like the one at Toddbrook Reservoir but is much bigger – 2,743 (1.7 miles) long compared with Toddbrook’s 200m (0.12 miles) length.

He thinks the presence of vegetation on the spillway is not a good sign.

"It isn’t good because whatever vegetation is there, its roots are going through the joint of the slabs or where the slabs are cracked," he said.

"There has to be some sort of ingress of water there somehow."

He said concrete slabs on water-retaining structures should have "water bars" in between the joints to stop water being able to get through. However, he was not able to see any bars in photos of the collapsed spillway.

"It looks like the slabs are not reinforced with steel," he said. "There has been ingress of water either through cracks or through the joints between the slabs.

"Somehow water has got in under the slabs and popped the slabs off."

Mr Meredith also thinks there is a problem with the design of the auxiliary spillway.

"When you look at the spillway the side kicks in, it’s not straight. So you are increasing the amount of water trying to get down that side," he said.

This is the same side of the spillway where residents have seen water flowing down and pooling in the past. It is also the same side that collapsed.

  1. Joe Public permalink
    August 5, 2019 11:11 am

    Perhaps if the Met Office’s longer-term forecasts were more accurate, the correct preventative measures would have been implemented?

    • Gerry, England permalink
      August 5, 2019 1:34 pm

      Or even the short term given the piece opens by saying the heavy rain forecast did not happen.

    • Mervyn Hobden permalink
      August 5, 2019 11:28 pm

      The Met office cannot make accurate forecasts as both weather and climate are non-linear systems – witness the lack of inclusion of the jet stream in climate forecasts until quite recently. There is no doubt that the increase in north/south loops in the jet stream is responsible for what is being perceived as ‘climate change’ and for which the current computer models have no explanation. In any non-linear system, with change in perturbation, the system goes through turbulence as it settles into a new equilibrium. We have been through this many times in history and as Paul has pointed out, I have yet to see any explanation from the modellers for the Medieval Optimum, which is now known to be world wide or, the mini-iceage, other than the one noted at the time – the lack of spots on the sun. They also rubbish documented history – at the Bishop’s Palace in Lincoln is a vineyard that in the 11th C was producing excellent white wines. Vineyards extended as far north as Newcastle. It was also predicted that we would see a dramatic shift in nightime temperatures with increased CO2 – this has not happened and the only increase in nightime temperature correlates to increased water vapour, which physics tells us is very likely. So far, the night time temperatures are lower than those I remember from the late 1950s in Sussex, when we also had violent thunderstorms, gorse fires on the South Downs and peat fires in our local woods. So, I don’t see the current climate as being that unusual, in the Medieval optimum, ships were able to sail from Northern Russia all the way to the Pacific as the ocean was free of ice, Not much sign of that yet!

  2. Hugh Sharman permalink
    August 5, 2019 11:20 am

    Thank you Paul! The picture says all! That dam badly lacked maintenance and of course its awful condition has nothing whatever to do with any “climate emergency”

    • steve permalink
      August 6, 2019 12:57 pm

      I experienced a collapsed factory floor slab in 75 when wet fill was used by the contractor. It did not fall into separate pieces like the picture shows because it was reinforced with mesh. This seems to have been clay topped with concrete slabs of domestic type, laid without a dpm.

  3. spetzer86 permalink
    August 5, 2019 11:23 am

    Just a guess, but wasn’t there a severe drought in the not distant past that resulted in hose pipe bans / limits, water restrictions, and the concept of new dams in the UK? Seems to me it was blamed on climate change and the rain, like snow, was something the UK wasn’t going to see again. If you believed that the rain was gone, you’d set your dams to maximum volume because you’d want to conserve every drop.

    When the rains returned, because that’s what they do, you’d probably just forget about your policy and forge ahead because climate change is still real, right? Sounds far fetched, but how and why water levels are maintained is a policy decision.

  4. August 5, 2019 11:29 am

    Reblogged this on Climate- Science.

  5. Frank Everest permalink
    August 5, 2019 11:49 am

    I’ve sent this to the Telegraph letters:

    SIR – I am puzzled as to why it is today necessary to use “high-capacity” pumps to lower the reservoir’s level. Was not the dam designed with sufficient cocks and spillways to cope with heavy rainfall?

    When the dam was designed in the 1830’s, heavy rainfall was not uncommon in the area. After it was built, in 1872 4.27 inches of rain had fallen in Macclesfield nearby in 12 hours – far in excess of the 2 inches in 24 hours last week. No problems were suffered then.

    We can assume that Victorian engineers knew what they were doing, and designed adequate drainage systems without pumps, to cope with worst-case rainfalls. Recent inspections by engineers to establish the safety of the dam should have found that the sluices and spillways were no longer fully operational. Why were they signed it off as safe?

    F.G. Everest, C.Eng, FIET, BScTech

    • saparonia permalink
      August 5, 2019 12:49 pm

      There would be have been Victorian and Edwardian engineers who passed on their unique experience and knowledge of the dam but over a couple of generations things are forgotten.
      I posted yesterdy about railway bridges in Yorkshire (ex West Riding), very close by, that had no foundations at all when inspected for maintenance a few years ago.

  6. Thomas Carr permalink
    August 5, 2019 11:56 am

    Does anyone know if there is a ‘dump valve’ for the reservoir which would be operated when needing to to expose the wet face of the dam for inspection?
    The panic for high output pumps appears to suggest that the drain valve was inadequate.
    There must be some form of regulated feed from the reservoir as the water is for maintaining a navigable depth in the Peak Forest Canal , not domestic consumption, hence the presence of a member of the Canal and River Trust at the press conference which we saw on the TV news.

    • It doesn't add up... permalink
      August 5, 2019 12:23 pm

      They emptied the reservoir in September 2009 for a programme of work that took well over a year

      The outlet seems to be near the base of the dam. Perhaps they feared it was not safe to use, or lacked capacity given the need to draw down the level rapidly.

      Paul: suggest you retitle the post to Update II to distinguish it.

    • Bertie permalink
      August 5, 2019 1:43 pm

      I seem to recall from the murky depths of my befuddled mind that ponds, lakes etc. had an automatic overflow outlet called (I think) a monk, which drained off the water if it reached above a certain height. I can scarcely credit that the Victorian engineers did not incorporate such a facility. (They probably did, only for it to be removed by modern-day ‘experts’!)

    • August 5, 2019 9:20 pm

      On YouTube 3 days ago a commenter at the “blancolirio” channel named “Petra1001uk” wrote this: (Note the bit that describes how the village priest first noticed the problem, called British Waterways and demanded they attend. A lone female turned up from BW, having no idea what she was coming to see or do, and tried to open the sluices by herself.)

      “Thankyou. I’m from the village of Whaley Bridge, and live about 200 yards north of the dam. I’m up the hill, so ‘safe’. I can almost feel the breath from the Chinook helicopters which, since 04.45 this morning have been packing the burst there with over 400 tons of bags of ballast.”
      “Pumping systems, pipes, smashing of the brook’s walls is what they’ve been working on since 1500 yesterday. 2 deluges occurred in that time, adding further to the volume.
      Only 12″ of water level has been diverted away and down the chute to the river (Goyt), due to the excessive volume and constant topping up of the water since they started yesterday.
      Current estimates are the dam has a 50/50 chance of breaching.
      Although there are about 6,500 reseidents, 90% live uphill and beyond the flood path, and are therefore not evacuated.
      What I will say created this imminent disaster is the absence of the Water Bailiff who, till about 15 years ago lived in the purpose built house at the edge of the dam since it was built – it’s a Victorian red brick structure. Those bailiffs were total guardians of every aspect of water supply maintenance, ecology and action according to every demand and need.
      Had there been a bailiff onsite, then he would have known the overspill had been gushing since at least Sunday night, and would have opened all the sluices below the dam to allow the build up to disperse naturally.
      Cut backs, changes of procedure, lack of investment and absence of effective, daily monitoring has contributed, in no small measure, to the state my village is in right now.
      It was the local priest who lives opposite the site entrance who went to inspect the dam yesterday morning, saw the concrete slabs liften up, the alerted the Canal & Rivers Trust (a national charity; previously it was govt. owned and called British Waterways), and demanded they attend. A lone female turned up, having no idea what she was coming to see or do, and tried to open the sluices by herself!
      That’s when all hell let loose, and now we’re at the state that there’s being a govt. emergency disater meeting taking place (COBRA meeting).”

  7. August 5, 2019 11:57 am

    The spillway wall adjacent to the damage is oblique and hindering the flow of water which would seem a sub-optimal design.

  8. Dave Cowdell permalink
    August 5, 2019 12:10 pm

    I worked on the dam in the 70s putting in monitoring equipment, and I believe that the spillway was being renewed. On a separate matter, a letter in the DT today from Daniel Carey-Davies of the CPRE using the problems at Toddbrook to ” demonstrate the need for urgent to tackle the impact of climate breakdown” A pity he had not reviewed historical rainfall data before his letter.

    • Bertie permalink
      August 5, 2019 2:05 pm

      I’m glad you mentioned this Dave – I could scarcely believe the nonsense the letter spouted. It is so full of drivel that it is worth the effort to reproduce it in full for those who don’t take the Telegraph:

      The shocking images of the devastation caused by floods across towns and villages in the Yorkshire Dales and the news that thousands have been forced to flee their homes in the Peak District clearly demonstrate the need for urgent action to tackle the impact of climate breakdown.
      With the floods coming just one week after Britain was baked by the hottest temperatures ever recorded, it is obvious that instances of extreme weather are increasing at an alarming rate.
      Our countryside will feel the full force of the climate crisis – but if we take a strategic approach to how we manage and use our land, it could also provide many of the solutions. The restoration of nature and natural systems is key to locking up carbon and mitigating the impacts of extreme weather, such as droughts, wildfires and floods. The Government must back up its ambitious net-zero carbon target with policies and the right amount of funding, ensuring that we plant more trees, regenerate our soils and restore our peatlands.
      Ambitious targets don’t do anything in themselves. Actions speak louder than words.
      Daniel Carey-Dawes
      Head of Rural Economy and Communities,
      Campaign to Protect Rural England,
      London SE1

      There is much that I could comment, but I will leave that to superior scientific minds. I will just raise one sense of outrage because of the lack of an ‘Oxford comma’!

      • August 5, 2019 2:16 pm

        I have sent a letter in reply. Hopefully they” publish it tomorrow!

      • John F. Hultquist permalink
        August 5, 2019 4:56 pm

        Daniel is hoping for government money for pet projects.
        Nothing more than that in his letter.

      • dave permalink
        August 5, 2019 5:40 pm

        What on earth is ‘climate breakdown’?

        People are in such a muddle, and so filled with vague fear. We might wonder how they got that way – but I think we know.

      • Dave Cowdell permalink
        August 5, 2019 7:52 pm

        Interesting that following my comment to him about ” pity you had not checked historical rainfall data” on his LinkedIn page, suddenly the link to the DT letter disappeared from his profile.

      • August 5, 2019 10:01 pm

        Daniel Carey-Dawes is an embarrassment to CPRE. He is political idiot (used to work for the Labour Party) who should be sacked for his incompetence.

      • Up2snuff permalink
        August 6, 2019 2:59 pm

        Carey-Dawes solutions: “with policies and the right amount of funding, ensuring that we plant more trees, regenerate our soils and restore our peatlands.”

        The policy appears to be extract more money from the taxpayer and spend it getting water to flow uphill. It cannot be done. IT CANNOT BE DONE. Water always flows downhill.

        More trees = more rivers and lakes blocked by branches and leaves & if maintenance is neglected and forests & woodlands not maintained, rivers and lakes not regularly dredged, then nature and gravity will win in the end.

        Regenerate our soils, that could be done with oil based fertilisers (oil? OIL??!!!) and with conventional composts plus set aside but inevitably rain = run-off = sediment = floods.

        Restore peatlands? Ummhh. Er. Pay attention, lad. Peatlands = fires = CO2 release = atmospheric pollution = asthma and premature deaths of thousands according to the politicians and ‘climatologists’. Remember the fuss in the media over the last two and a half years?

        Phillip, you are right about Carey-Dawes: “He is political idiot (used to work for the Labour Party) who should be sacked for his incompetence.”

  9. August 5, 2019 12:14 pm

    Environment Agency activities to comply with EU directives will have had an impact –

    (Word clues: sustainable, habitat etc.)

    ‘reducing the need for channel maintenance’ – means not doing enough…

    “More than 1,000 properties across Delph, Uppermill, Stalybridge, Mossley, Hayfield, Glossop and Whaley Bridge will benefit from the pioneering ‘Slow the Flow’ project. The project will ‘slow the flow’ of water reaching rivers and watercourses upstream of communities at flood risk.

    Measures to slow the flow of water – from peat restoration to woodland planting and leaky barriers – will trap sediment and help to reduce the need for channel maintenance. The project will be carried out by a wide range of partners, including the Irwell River Trust, United Utilities and Cheshire Wildlife Trust.”

  10. swan101 permalink
    August 5, 2019 12:24 pm

    Reblogged this on ECO-ENERGY DATABASE.

  11. PhilH permalink
    August 5, 2019 12:28 pm

    The Daily Mail had interesting drone footage of the reservoir before the collapse.

    The OS map shows a bypass overflow from the head of the reservoir, presumably operated at the weir on the river just before it enters. I wonder whether this was working properly or whether there was adequate monitoring of the flow and level.

    In earlier years, many reservoirs had a bailiff on site with his own cottage, although I don’t know whether this was the case at Toddbrook.

  12. saparonia permalink
    August 5, 2019 12:35 pm

    Excellent researching. Thank you

  13. CheshireRed permalink
    August 5, 2019 1:53 pm

    So all the usual MSM suspects who’ve been hysterically reporting ‘climate change’ will be retracting then, yes?


  14. steve permalink
    August 5, 2019 2:14 pm

    From the photos it is obvious that the dam was constructed with concrete slabs resting on a clay base, which has subsided, perhaps through long term erosion, and the slabs have collapsed. How any competent person could blame global warming or heavy rain is beyond belief. The dam should have been drained and rebuilt.

  15. August 5, 2019 2:57 pm

    I was so incensed after reading Carey-Dawes’ letter that I too wrote to the Telegraph referring him to this website so that he could learn some facts about CC.
    Doubt it will be published though as the mainstream media seem obsessed with the ‘concensus’ and are reluctant to publish opposing views it seems. Very frustrating!

  16. MrGrimNasty permalink
    August 5, 2019 3:19 pm

    On one of the weather forecasts they had rainwater totals for places in the relevant area and I think just over 200mm was at the top – one place way out in front. I wasn’t paying close attention so short on detail I’m afraid. A Buxton site is claiming 104mm June, 153mm July, 11mm so far August.

  17. THX1138 permalink
    August 5, 2019 4:12 pm

    To make things clear, the damage to the spillway was caused by rainfall, not water spilling from the reservoir. Ordinary erosion caused this undercutting because the spillway was not properly maintained to start with. Notice all the plants poking through the concrete protection for the spillway. This was a severely weakened structure before the rain.

  18. tonyb permalink
    August 5, 2019 4:33 pm


    According to his web site, this is one of the volunteers manning the met office station in Buxton and he maintains his own weather station there as well. He might be more helpful than the Met office can be

    This next site is also interesting as you can move the arrow around to get heights of places. I have no idea of the catchment area of the relevant rivers but the highest part of the Pennines is at 2000 feet and with Buxton at around 1000 feet these are remarkably similar to Dartmoor near where I live and the principal town on the moor- Princetown.

    As you know there is a huge difference in rainfall amounts the higher you go and I would imagine the rainfall at 2000 feet would be far greater than at 1000 feet high and there would be far more days with a rainfall greater than 40mm than just one a year, that could affect rivers and reservoirs.

    Incidentally the Dartmoor authority have just declared a ‘climate emergency’ citing the IPCC. I have just written to the chair pointing out the PCC have never actually said this-it comes from activists- and that Dartmoor is a fine showcase for climate changes throughout the Holocene and their own web site mentions the climate was warmer in the past!


    • August 5, 2019 5:07 pm

      Thanks Tony

      I see he reckons 125mm for 7 days (and 153mm for July as a whole)

      The Shoothill site gives 202 mm for the Cat & Fiddle, which is the top of the moors above Buxton at an altitude of 1690ft. I have driven over it a few times, and had lunch in the pub!

    • August 7, 2019 3:56 pm

      >huge difference in rainfall amounts the higher you go

      Sure, but the amount of rainfall in the catchment area (here 1,700 ha) is not the primary factor in reservoir and flood design. The runoff in a certain time at the location of the dam is more important. And the surrounding hills did not change in the last centuries.

      Now someone might say, that the broken down climate brings exponentially more rain in higher grounds. And interesting question that needs to be answered with government money.

      @Paul: Wonderful site. Did the Daily Telegraph publish your answer?

    • August 8, 2019 6:24 pm


      Turns out that the Victorian engineers accounted for the greater rainfall at higher grounds. Together with different estimated evaporation values they saw a negligible effect:

      At Todd’s Brook Reservoir, 620 feet above sea, 38·39 Water measured inches + 10 for evaporation = 48·39 Total Rain-fall inches
      At the top of the hill, 1,500 feet, 29·50 measured + 20 evap. = 49·50 Total

      Source: Page 288 of the Minutes of Proceedings of the Institution of Civil Engineers, Band 7, 1848,

    • Phil. permalink
      August 9, 2019 3:36 pm

      Buxton isn’t a good comparison with Whaley Bridge since it’s in the rain shadow of the Pennines and Whaley Bridge is not.

      • August 9, 2019 3:40 pm

        Buxton is the only long running record in the area, so is relevant for long term trends.

        In any event, it is not the rain on Whaley Bridge which is relevant, but the rain on the Buxton hills up valley

        The data from Chapel en le Frith is also highly relevant to Whaley Bridge.

      • Phil. permalink
        August 10, 2019 12:35 pm

        I think you need to revisit your geography!

  19. It doesn't add up... permalink
    August 5, 2019 4:38 pm

    Drought in 1911:

    Dam emptied prior to repair, 14 September 2009:

    An historical problem:

    Manchester, Sheffield and Lincolnshire Railway
    Canals Department,

    22 July 1895

    Dear Sir


    In reply to your instructions, respecting the above. The following information I have received from a Mr William Southern, Snr. No 4, Roach Cottages, Whaley Bridge. This man informs me that he has worked in this coal Pit and is acquainted with the old shaft that exists in the Todds Brook Reservoir. He states that the said shaft has not been sunk the full depth, but is stopped some few yards before reaching the coal. He says there has been a heading driven, from the Coal, outside the Reservoir, to the Bottom of the old Shaft that is in the Reservoir. He states that the said Shaft has been tipped full of Puddle from the Bottom and is protected on the Top with large stone flags. Some 10 or 15 years ago, our company complained of water escaping from the Reservoir down this shaft. Southern was one of the men employed to test this complaint. He states there was a large quantity of water lying in the pit where the Coal had been worked. This water he assisted to pump out with hand pumps; they succeeded in getting it dry and found the Heading leading to the old Shaft, examined the same and found that there was no escape of water but that it was practically dry. He states that perfect reliance can be placed on the above statement.

    Undated photo, presumed early 20th century


  20. John F. Hultquist permalink
    August 5, 2019 4:59 pm

    Rex Murphy has a post on the Google Summer camp.

  21. August 5, 2019 5:27 pm

    Paul, well done on finding that rainfall data.

    Andrew Montford has some data on flow rates in the river Goyt, showing nothing changing since the 1970s.

    Increasingly these days it’s the sceptics who present real genuine data while the so-called climate scientists present anecdotes and wild predictions.

  22. tonyb permalink
    August 5, 2019 5:40 pm


    ‘Increasingly these days it’s the sceptics who present real genuine data while the so-called climate scientists present anecdotes and wild predictions.’

    we obviously need to change our tactics and present someone as a bona fide believer who then innocently presents real facts amongst the rhetoric .

    The msm likely don’t know the difference between the poorly thought through XR type responses laced with ‘wishful thinking’ facts and the ‘real’ facts, so it may be some time before they realise they are being fed correct information.


  23. Schrodinger's Cat permalink
    August 5, 2019 7:38 pm

    I’ve not had time to read all the other comments so apologies if I am repeating things. I wondered why the dam was full towards the final part of the summer. It reminded me of a major problem near Brisbane a few years ago. A dam that was designed to prevent floods became dangerously full, past its recommended maximum and faced danger of collapsing.

    The authorities had to take emergency action and release water that did cause some flooding down stream, but that was better than catastrophic collapse. As far as I remember, it seems that alarmist claims of climate change convinced the authorities that draughts would be severe so they allowed the dam to fill to near maximum to provide water later on in the expected draught. The draught never happened and the already full dam could not perform its function which was to prevent flooding, instead it contributed to flooding.

    It would not surprise me if something like that happened here. There are so many lies about extreme temperatures, extreme weather and climate emergencies that anything is now believable.

    • August 5, 2019 10:25 pm

      Is there even such a thing as an ‘expected drought’? It seems to imply longer term certainty of weather than anyone could possibly offer.

    • Graeme No.3 permalink
      August 6, 2019 12:10 am

      Wivenhoe Dam was planned in the early 1970s as a flood mitigation and water storage dam.
      (Thus the water storage level was intended as about half the full capacity, leaving room to absorb some of any heavy rain, as is common in Queensland).
      The 1974 Brisbane flood highlighted the need for flood protection for South East Queensland. (As did the catastrophic 1893 flood). On 11 January 2011, Wivenhoe Dam reached its highest level ever, 191% of normal water supply storage capacity, as it held back floodwater.
      Because it is an embankment dam, it was not designed to spill over its crest or overtop and there is a risk that if waters spilled over the crest, this could erode the (earthen) dam wall and potentially cause the dam to fail
      The major problem was that the authorities believed various Doomsayers that Climate Change would result in lack of water, and switched the main purpose from flood control to water holding. Possibly 400 m.m. (15.7 inches) fell in the days immediately before the flood. Coupled with storage at 175% at the originally planned level, the rain raised the height to 195% of capacity when panic set in and lots of water was released into a swollen river.

    • Duker permalink
      August 6, 2019 1:29 am

      That was Brisbanes problem. They built a large dam inland from the city to control the regular flooding which would affect the CBD.
      However they decided to make the dam dual purpose and supply water for the city. The result is the dryer months the level is higher, but those dryer months also have a shorter periods of intense tropical rainfall.
      Final result is the the dam water level rises rapidly to the crest during intense summer rain meaning the spillways are opened wide and peak flow downstream floods the CBD again.

  24. Bloke down the pub permalink
    August 5, 2019 8:04 pm

    I don’t have any knowledge of the area below the dam but I suspect there may have been a lot of development since the dam was built. The original design may have allowed for the rapid drawing down of water level but that may now be compromised by the risk of flooding new properties.

    • Adrian, East Anglia permalink
      August 5, 2019 9:49 pm

      Bloke down the pub:

      You are probably right about subsequent building development. But draining the reservoir means that the water has to go somewhere, whether by means of discharge from multiple ‘high capacity’ pumps or via the inbuilt draw-off systems. The latter, having been refurbished as part of the £half million repair scheme of 2010, should be up to the job, though I suspect they would be unable to generate the necessary coefficients of drama, alarm and hysteria required for such a ‘crisis’!!

    • It doesn't add up... permalink
      August 6, 2019 1:44 pm

      I tried a search for old maps of Whaley Bridge which produced versions going back at least to the early 20th century. The town was well developed along the Goyt and the main road below the reservoir. Some of the larger works buildings appear to have been replaced with more modern designs. The major expansion of the town has been on the hillside out of the flood risk area.

  25. Svend Ferdinandsen permalink
    August 5, 2019 11:22 pm

    It looks like a repeat of the problems at Oroville.

    • dave permalink
      August 6, 2019 8:39 am

      “a repeat…”

      ‘Deja vue’ all over again. Speaking of which, here is the latest RSS analysis of Global Lower Atmosphere Brightness-Temperature Anomalies, in July, as observed from space, together with the ten years’ previous, rounded to one hundredth of a degree (!):

      Year July

      2019 + 0.71 C

      2018 + 0.64

      2017 + 0.62

      2016 + 0.68

      2015 + 0.49

      2014 + 0.54

      2013 + 0.40

      2012 + 0.41

      2011 + 0.48

      2010 + 0.70

      2009 + 0.47

      July is supposed, in some sense, to be the hottest time of the year for the world (?). So it looks like a reasonable month to examine for grounds for hysteria.

      There is a lot of dry air coming off of Africa, wending its way to the Caribbean. No hurricanes in August there, I opine.

      • August 6, 2019 9:14 am

        Duker – sounds like Brisbane has been a planning mess for a while..

        Until the 1980s it was rare to find a house in the inner-city that wasn’t elevated. But then several things occurred: the city’s population grew much larger and so did the houses. People began removing the stilts and building in underneath – new bedrooms, living spaces, etc.

        At the same time, the climate began to change. The Christmas/new year rainfall seemed not so heavy anymore and not so long. And then during the long drought of the mid-2000s, many people in Brisbane found it difficult to remember that the city had ever been sub-tropical at all, that heavy rain and flooding were part of its DNA.

        I remember just a few years ago a builder friend of mine saying that there was going to be trouble. That many of the houses were no longer being built to suit the Brisbane climate. That we’d all become so used to dry conditions that we’d forgotten to build for the wet.

        Not that the UK is any different as Lamb reported in the 1950s;

        I have always thought it a misfortune that the general introduction of plumbing into British homes coincided with the quite unusual run of mild winters between 1896 and 1936. And possibly some of the modern glass architecture and the hill-top sites with an open south-west aspect which became so desirable a few years ago seem less to be recommended in the 1950s.

        HH Lamb – ‘The changing climate, past and present; Weather, October 1958, Vol 145, pp. 299-318

      • dave permalink
        August 6, 2019 9:49 am


        The street in north London where my parents lived from 1939 was newly built then. The plumbing and roof drainage was hung on the outside walls, exposed to the atmosphere – which meant more room inside the houses, of course.

        However, everybody had to enclose, in some way, their plumbing, in the 1950s, because of the change of climate. The least little cold snap, and it froze solid overnight. My parents moved to a new build house in 1962, making sure it had all the plumbing properly protected!

        People, then, reacted to what was clearly happening, and not to what they were TOLD was happening. They were not such silly sheep as now.

  26. August 6, 2019 10:15 am

    This is interesting. My observations from as a sailor at a nearby Canals and Rivers Trust reservoir is that it is kept at a higher level than it was 10 years ago. As a Whaley Bridge resident I can say that the spillway that has failed is seldom used. I suspect it was not really designed to cope with the volume of water going over it. I think the questions about maintenance are missing the point and that the management strategy for the water level is the issue that needs to be addressed.
    Some comments have expressed doubt about the role of climate change, but the chaotic nature of weather makes that easy to claim. Climate change makes such events more likely. My personal observation was that the rain on Wednesday was the heaviest I have ever seen.

    • Neil Wilkinson permalink
      August 6, 2019 12:29 pm

      Looking at the previous Whaley Bridge update, it would appear that the volume of rainfall was unexceptional and nothing that a well managed and maintained dam could not have coped with.

      • Smoke&Mirrors permalink
        August 6, 2019 3:51 pm

        Spot on!

    • It doesn't add up... permalink
      August 6, 2019 1:35 pm

      One of the actions to help resolve the situation has received little attention because it was at the far end of the reservoir. The Army were called in to build a sandbag dam across the brook feeding the reservoir, which is apparently expected to remain in place for a year or so while repairs are done. Presumably the sluices that allow the flow to be diverted to the channel for the brook that skirts the reservoir were not operational, in another case of inadequate maintenance. They were probably used when the reservoir last underwent major repair in 2009-11. Lower levels you may have seen a decade ago will almost certainly have been related to the need for repair, or the slow refill afterwards. It was drained and the fish moved elsewhere.

      The “new” spillway was installed in the late 1970s because the original one at the corner above the sailing club was estimated not to be large enough. Its capacity was set to be comfortably sufficient. The nature of its construction is much more questionable. There is record of damage in 1964, although I haven’t seen details.

  27. Dave Cowdell permalink
    August 6, 2019 11:21 am

    In the late 70s and early 80s the Geotechnical Control Office in Hong Kong recognised that they had severe slope stability problems. I had the contract to monitor the rapid and transient rises in water level, up to 20 m in response to heavy rainfall. In the past, there had been landslides resulting in collapse of multistorey housing units. Now in HK rainfall is particularly intense and I have seen 600mm in two hours and 968mm in 24 hours. The Government came up with schemes to engineer the slopes to eliminate the risk. The Victorians were aware of the risks with the dams but I wonder whether their understanding has survived, and that essential maintenance and investigation of structures is carried out to cope with a relatively small amount of rainfall?

  28. europeanonion permalink
    August 6, 2019 3:03 pm

    A couple of years ago the the Murray-Darling river system caused massive flooding and the reason was that the authorities had kept dams at high levels as a hedge against drought. Paul alludes to the dam’s high water level and wonders why this was so.

  29. Dr Michael Hope permalink
    August 6, 2019 7:43 pm

    As someone who works within another governmental service the trouble is these days we have management meetings, risk assessments , protocols, they will have worked out what happens in a once in 1000 year and once in 100 year scenario and they will have worked out that financially it’s easier to avoid the regular maintenance because that thing probably won’t happen in their financial budget this year .
    But they are at the hands of nature, this is why school buildings, hospitals ,roads railways are not maintained .
    We have a reactionary economy that deals with problems and then rushes in to put it right.
    It says it will learn lessons, but rather than paying regular teams to maintain the infrastructure which is deemed a protectionist nannying waste of money ,we have a societal problem .
    You don’t have to be a dam engineer or hydrologist, you just know if you owned a house ,if plants were growing out of the brickwork or the roof that it’s not a good idea you get it fixed .
    Water is the biggest damage of any structure known to man .
    It freezes, it expands; it’s just so depressing because there’ll be a great expensive report, we will be meant to learn lessons until the next cost saving exercise causes problems somewhere else. .
    Human environments etc are put at risk and nothing will change .
    Thank you for your in-depth journalism, we’re meant to live in a free society where information we pay for is available to all, they are a civil service/ servants meant to work for us . Old terminology anachronistic words that they mean what they say they however we’re not as free as a society maybe were better than others it is very depressing now that we react rather than with proactive.

  30. john cooknell permalink
    August 6, 2019 10:21 pm

    Records of flooding from canals and reservoirs are erratic as there is no requirement
    for the Environment Agency to show historic flooding from canals and raised
    reservoirs on plans. In particular, the NPPF does not require flood risk from canals
    and raised reservoirs to be shown on the flood map. Risk mapping from inundation
    as a result of reservoir breach is provided by the EA on their web mapping, however,
    this mapping does not include risk from canals. It should be noted that overflows
    from canals are relatively common due to flows from land drainage and their frequent
    lack of overflows. Occasionally major bank breaches also occur, leading to rapid
    and deep flooding of adjacent land.

  31. john cooknell permalink
    August 6, 2019 10:44 pm

    Not only do canals occasionally overtop in places
    due to high inflows from natural catchments (i.e. where inflows are higher than the
    capacity of the flood control structures), but they are also vulnerable where
    overtopping occurs from adjacent watercourses. Additional water from adjacent
    watercourses must be routed/conveyed by the canal which may cause issues
    elsewhere, not only within the catchment of interest but also in neighbouring
    catchments, as the canal crosses catchment boundaries. Additionally, the canal
    itself can reduce flood risk where Canal and River Trust (C&RT) control flood flows
    within the canal, or accept flood waters either for temporary storage or transfer.

    At present canals do not have a level of service for flood recurrence (i.e. there is no
    requirement for canals to be used in flood mitigation), although C&RT, as part of its
    function, will endeavour to maintain water levels to control the risk of flooding from
    canals to adjacent properties. It is important, however, that any development
    proposed adjacent to a canal be investigated on an individual basis regarding
    flooding issues and should be considered as part of any FRA.

  32. john cooknell permalink
    August 7, 2019 12:12 am

    The EA produce reservoir flood maps associated with large reservoirs that hold over
    25,000 cubic meters of water. These maps are available on the EA web site and help
    identify areas potentially affected by reservoir flooding; they are only intended as a
    guide and are not a prediction of what will happen. Due to the sensitivity of the
    information the maps are at relatively small scale (limited detail) and do not provide
    information on potential depth or speed of the flood waters associated with reservoir
    flood risk. The maps display a realistic worst case scenario of the largest area that
    might be flooded if a reservoir were to fail and release the water it holds and are
    suitable for emergency planning purposes

  33. Julie Potts permalink
    August 7, 2019 10:29 am

    I absolutely agree with Paul and the civil engineer’s comments in his report. I posted a comment on Toddbrook Reservoir Facebook several days ago which referred to the cause of the failure of the dam. I have been in the construction industry for 30 years and have dealt with similar applications many times. In this instance, overspill water has ingressed behind the concrete slab construction through the gaps between them, undermining the concrete slabs. The force of water has then dislodged the slabs and washed away the material beneath which has created the huge voids you can see beneath the slabs. I note Roger’s comment about ‘steel water bars’ but l don’t think this type of application would have been used in 1838 when the dam was built. However, the slabs should have been properly maintained by regularly grouting the gaps to keep the structure watertight to prevent any ingress of water into the structure. The evidence of plants growing in these gaps for several years proves this has not been carried out. I would have expected any engineer who inspected the dam to immediately order the removal of vegetation from the spillway and the gaps grouted to keep the structure watertight. I have been a resident in Whaley Bridge for 30 years and l have never seen this done. This is a case of gross negligence due to complacency.

    • john cooknell permalink
      August 7, 2019 10:05 pm

      paste the post ijust did into the Facebook site, says it all really.

  34. It doesn't add up... permalink
    August 7, 2019 5:24 pm

    There are now pictures of the spillway at Wikipedia showing it heavily overgrown in 2005, but almost free of vegetation and with the gaps between slabs at the sides sealed with tar in 2014. Maintenance to that standard has evidentl hiy been sporadic over the decades.

    There is now talk of completely rebuilding the reservoir which is a decision that should surely await proper core tests of the condition of the dam. However the spillway clearly needs to be removed and replaced or moved to the side of the reservoir, with repair to the dam itself.

  35. john cooknell permalink
    August 7, 2019 9:24 pm

    76. Toddbrook Incident date: December 1964 Construction details The reservoir was constructed in 1840-41 to supply water to the Peak Forest canal. It is on the north-west edge of the Peak District National Park near Whaley Bridge. The embankment is 24 m high with 1:2 upstream and downstream slopes. Further details of the dam construction are given in Incident No. 23. Incident description The water level was one metre above the spillway crest for a period of 24 hours following heavy rain and it took another two days for the level to fall to normal top water level. Damage was caused to the lower part of the spillway channel. Some parts of the side walls were washed out and some erosion took place on the right bank adjacent to the downstream toe of the dam. The main deterioration was caused by excessive flow down the spillway. Response The 1964 flood damage was repaired in 1965 and subsequent flood studies confirm the spillway was inadequate to take the design flood. An additional spillway was built in 1969 with a 75-m weir built over the southern section of the embankment discharging over a concrete-protected portion of the downstream face. The sill level is above the original spillweir level. Lessons The incident showed that despite the dam being in existence since 1840, the spillway was inadequate. The incident instigated a flood study of the reservoir resulting in an additional spillway constructed.

    22. Toddbrook Incident date:1977 Construction details The 24-m high dam consists mainly of boulder clay with sands and gravels. There is doubt about the existence of a puddle clay core even though it is shown on the original construction drawings. The dam is founded on fluvio-glacial sand and gravels, glacial till overlying a faulted sequence of mudstones, sandstones and shales of the Millstone Grit Series and Lower Coal Measures. Incident history The dam has a history of leakage. Since 1880, there were complaints about leakage into mine workings. In 1930 leakage was observed at the toe of the downstream slope. As a result of an Evidence Report – Lessons from historical dam incidents 124 investigation into the leakage,a depression was found on the upstream slope. This was investigated in 1931 and the area was then reinstated. Incident description In November 1975 when the reservoir was low, a depression was noted in the same position on the upstream face as the 1931 depression. In Autumn 1977, 120 mm of subsidence was measured since 1975. The reservoir was emptied to inspect the full extent of the depression and revealed a crater approximately four metres across at the upstream toe partly infilled with silt and into which a tree appeared to have been sucked. Investigations Extensive investigation included boreholes, sampling and piezometers. Exploratory shafts were sunk on the upstream and downstream faces between 1978 and 1980. In 1981, a 1.2-m diameter masonry culvert was found beneath the dam, possibly for stream diversion during construction. Tracer tests showed this to have formed a leakage path through the dam. Remedial works In 1981, a compacted clay blanket was placed over the suspect area of the upstream toe and the bed of the reservoir. To solve the leakage problem, a single row grout curtain 60 m long within the clay core was formed using the tube-à-manchette system. The reservoir was refilled in December 1983. Lessons Until the reservoir was drawn down, the extent of the crater caused by erosion was unknown. The good practice of periodic inspection of the upstream face of a dam is illustrated by this incident. References: Anon, 1977; Anon, 1978; Binnie, 1987.

  36. Phil. permalink
    August 8, 2019 8:31 pm

    The rainfall amounts shown on the following site indicates that 2019 has been exceptional at Whaley Bridge over the last decade particularly this summer.

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