Talk:Toddbrook Reservoir

Derbyshire portal

This picture will be on the Derbyshire portal in September Victuallers (talk) 13:58, 28 August 2009 (UTC)

When was it built

The internet in general (probably copying from wikipedia) say 1831. this page which should know what it is talking about say 1838 with planning not starting until 1834. Civil Engineering Heritage: Eastern and central England says opened in 1838. The EA says here on page 140 that the thing was built 1840-41. I'm going with 1838 for now.©Geni (talk) 17:05, 1 August 2019 (UTC)

Hmmp EA says new spillway built 69 while Civil Engineering Heritage say 71.©Geni (talk) 17:58, 1 August 2019 (UTC)

[1] this says 1838 and 1971 respectively. Richerman (talk) 12:40, 2 August 2019 (UTC)

Thats what I was refering to as Civil Engineering Heritage.©Geni (talk) 14:32, 2 August 2019 (UTC)

Oops, sorry, of course it was. Richerman (talk) 15:30, 2 August 2019 (UTC)

Possible source

The significance of problems and remedial works at British earth dams. Proceedings of BNCOLD/IWES Conference on Reservoirs 1986, Edinburgh, 123-141.

©Geni (talk) 19:56, 1 August 2019 (UTC)

Dam dates from around 1794

“Todd Brook dam, which still exists, was built to provide a water supply for the Peak Forest Canal. It is some seventy feet in height, two hundred or so broad at its base and some seven hundred feet in length, and was built in or around 1794.”[2]

The later 1838 date might refer to the change in its use, from providing water for the canal to supplying drinking water. Indeed, construction of the Peak Forest Canal began in 1794 and the first barges travelled along the new canal in 1796. The canal was completed in 1805.

From Simpson AB. Legal Liability for Bursting Reservoirs: The Historical Context of” Rylands v. Fletcher”. The Journal of Legal Studies. 1984 Jun 1;13(2):209-64

--Diamonddavej (talk) 10:42, 2 August 2019 (UTC)

Reservoir is later that the canal. See here under water supply https://www.macclesfieldcanal.org.uk/interactions-part-1-1826-39 . They started talking about it in 1834 due to water supply issues.©Geni (talk) 11:46, 2 August 2019 (UTC)

According to [3] it was brought into service in 1838. Does it supply drinking water? Richerman (talk) 12:44, 2 August 2019 (UTC)

Probably not? While some canal reservoirs were taken over by water companies those that weren't tended to remain purely for canal use.©Geni (talk) 14:33, 2 August 2019 (UTC)

This local history site says: "Toddbrook and Combs are not reservoirs for drinking water; they are simply there to supply the canal." Martinevans123 (talk) 14:40, 2 August 2019 (UTC)

This, from the local council, puts the date at 1837, and gives various parameters about the dam and its lake (section 4.9.2). -- Finlay McWalter··–·Talk 15:03, 2 August 2019 (UTC)

Quite an apposite document. Do you know if that is the latest assessment, from 11 years ago? I guess that's relatively recent in the rather slow-moving world of reservoirs. Martinevans123 (talk) 15:11, 2 August 2019 (UTC)

So built in 1837 and brought into service in 1838 - that seems reasonable. Richerman (talk) 15:38, 2 August 2019 (UTC)

This document from the local council should be used with care. For example the table 4.5 has a copy&paste error in the first and last row of the last column. Hb (talk) 16:24, 3 August 2019 (UTC)

No low-level outlet?

Is there no low-level outlet to reduce the level of the water? Pumping with fire engines needs 100 or 1000 times more time .. --Peter2 (talk) 17:34, 4 August 2019 (UTC)

I think the owners, emergency services or council would have known about one or managed to find it by now? Martinevans123 (talk) 17:37, 4 August 2019 (UTC)

There will be (to feed the canal) but it will have a fairly limited capacity.

I had assumed Peter2 meant something additional to the canal feed. In fact, I now see that this source, dated 1 August, says this: "This is being done by opening the ‘scour’ or low level outlet (like a plug in a bath) – but the water can only be released in a controlled manner in order to prevent flooding downstream and also damage to the dam (an earth embankment dam like this one could suffer landslips if the reservoir level was dropped very rapidly)." Martinevans123 (talk) 20:18, 4 August 2019 (UTC)

This 2011 page discusses the dam in detail. In particular, it shows the 2 normal discharge pipes, both only 15 inches in diameter. It also talks about the 2006 works being in response to a new requirement that the reservoir height be halved within 5 days. The 2006 works replaced the valves and intake grilles, and relined the pipes. So that normal low-level discharge is only those 2 rather small pipes. That's enough to maintain the canal (which is still fed from the Todd Brook, which is about 6 feet wide at this point), even when the canal was in heavy use (cycling the locks is a major use of canal water - with the canal now being mostly a tourist thing, the locks won't get cycled even a 10th as much as they would in the canal's industrial heyday). That "5 days until half height" thing is ambitous in this case, because a) the reservoir was (and still will be) receiving lots of net inflow from the surrounding land, even with some of the major inflows now diverted and b) if the failure is a slump at the dam's footing, or a penetration of the clay membrane at a low height, then they'll need to drain the reservoir empty. Obviously the lower the head of water the less energy it stores, which lessenes both the likelihood and damage of a sudden failure - but with those two modest little pipes, and the auxilliary spillway (the big wide one) damaged, they need all the pumps they can get. -- Finlay McWalter··–·Talk 20:38, 4 August 2019 (UTC)

Also on the picture on that site, note the "colliery drain" stuff in several places, indicating the colliery works are terribly close to the dam. Based on coalfield subsidence in other places, I don't think the Victorians had a very good grasp of the long-term issues with building above collieries (or mining far beneath existing structures). -- Finlay McWalter··–·Talk 20:46, 4 August 2019 (UTC)

So do we know if those two feeder values would now be now fully opened? Or would that be too much for the canal to bear? I see no mention on that plan of any "‘scour’ or low level outlet (like a plug in a bath)". Martinevans123 (talk) 21:02, 4 August 2019 (UTC)

From that source, it seems both pipes take their intake from a covered grating on the reservoir floor, some distance in front of the dam itself - not from a penetration of the dam. So they're already as low as anything could be. If they did those works in 2006, with the intention that they be able to half the reservoir height in 5 days, presumably they were satisfied that the watercourses below would be able to withstand that - otherwise they would surely have had to make comparable improvements there too (or mandate the reservoir be habitually maintained at a lower head). -- Finlay McWalter··–·Talk 21:18, 4 August 2019 (UTC)

Ah yes, I see. Thanks for explaining. Martinevans123 (talk) 21:30, 4 August 2019 (UTC)

I think it is clearer now, but on the German Wiki there is a good plan (cross section)to show the low outlet (Grundablass): https://de.wikipedia.org/wiki/Grundablass --Peter2 (talk) 19:05, 5 August 2019 (UTC)

That's a nice informative picture, and certainly explains for dams in general. But there are a dizzying array of types of dam drainange and spillway features (I read about 50 pages of an Indian dam design textbook yesterday, until my brain hurt), and it's not sufficiently clear exactly how this one is configured. Unfortunately media sources about the current issue concentrate on exiting things happening at the top (like helicopters), and there's not much in more technical sources (who may find this to be and old boring dam). Presumably the civil engineering magazines will publish something technical but accessible in the coming weeks (perhaps like the 737-MAX discussions), but right now we don't have much to go on. -- Finlay McWalter··–·Talk 21:42, 5 August 2019 (UTC)

I'm pretty sure this dam thing is grounded for good. Martinevans123 (talk) 21:46, 5 August 2019 (UTC)

There's a good chance there are no surviving plans and the dam hasn't had much interest from historians (hadfield doesn't even mention it).©Geni (talk) 19:46, 6 August 2019 (UTC)

@Finlay McWalter @©Geni Despair not. The intro to [this book review] says it has "an appendix with Nicholas Brown's 1836 specifications for the Todd Brook Reservoir dam giving an insight into the engineering methods of the time". It's a bit dear to buy at £55 though. Maybe there's a library copy available somewhere. Richerman (talk) 16:23, 7 August 2019 (UTC)

Yes, there is a reference copy in Manchester Central Library if anyone has the time to go there [4]. However, according to the book review there won't actually be any drawings for the dam as it says that the use of isometric drawings were a French military secret at that time and "English engineers continued to brief proprietors and workmen using scale models". Richerman (talk) 16:35, 7 August 2019 (UTC)

I think wikimedia UK offers grants for buying books.©Geni (talk) 06:58, 8 August 2019 (UTC)

£30 is hardly a fortune for a hardback. You get 220 pages for that. Or how much is access via Taylor and Francis Online? I'm sure that book would be useful for other articles, such as Peak Forest Canal or Cromford and High Peak Railway. But how exactly are Brown's specifications presented, if not by means of isometric drawings? Martinevans123 (talk) 09:10, 8 August 2019 (UTC)

@Martinevans123 If you can find a copy at £30 grab it - the only ones I've found for sale online are second hand ones for £55. The Taylor and Francis Online access is £32, unless you have an Athens account, but that is only for the book review which wouldn't be much help. Richerman (talk) 12:22, 8 August 2019 (UTC)

Oh I see, thanks. Such is the economic push factor of Wikipedia editing! Martinevans123 (talk) 12:26, 8 August 2019 (UTC)

I work opposite Manchester Central Library. I could probably photocopy the relevant pages and transcribe/paraphrase the relevant material. Leave it with me. Dave.Dunford (talk) 11:50, 8 August 2019 (UTC)

Good man that man! We'll be ahead of the public enquiry at this rate :-) Richerman (talk) 12:27, 8 August 2019 (UTC)

... or even a "nationwide review of dam safety"? Martinevans123 (talk) 12:34, 8 August 2019 (UTC)

I went in to the Library. It's not on the open shelves so I need to ask for it to be extracted from the stack, and there's apparently a £6 photography fee "though they may cut you a deal if it's only a page or two". I'll see what I can do next week. Dave.Dunford (talk) 20:24, 8 August 2019 (UTC)

Oh no!! Don't take it from the bottom of the stack! Martinevans123 (talk) 21:14, 8 August 2019 (UTC)

@Richerman:@Martinevans123: Sorry for long radio silence. I've now arranged access to a copy of the aforementioned Peak Forest Canal book from the stack at Manchester Central Library, on Thursday 12th. I'll photograph the relevant pages for my reference and paraphrase anything that seems relevant, but what specifically are we looking for? Dave.Dunford (talk) 13:23, 10 September 2019 (UTC)

The design specifications and anything else of interest really. Richerman (talk) 16:26, 11 September 2019 (UTC)

I now have photocopies of the relevant pages from the Boyes book. Seven pages in the main body of the book are dedicated to Toddbrook Reservoir, plus the aforementioned Appendix. I'll digest these and paraphrase the content. The Appendix mostly concerns the dam embankment and its core, but the following refers to the outlet pipes:

"I see by the Section drawn by Mr Wood he has shown his pipes whereby to draw the water out of the Reservoir to the Canal to be at an elevation of about 5ft 6in above the surface of the water in the Brook which is too little for deposit, their [sic] ought at least to be 10 feet to prevent matter getting into the pipes which might stop the passage of the water, he has as I have before observed supported the Pipes with stone pillars which must be avoided.

So soon as the Bank is approaching to the Elevation of 10 feet from the surface of the water in the Brook a Trench must be cut of the solid ground in which to lay the pipes in a line as straight as possible at least 3 feet wider than the Diameter of the pipes on each side and to the depth of 3 feet below the level at which the pipes are to be laid – a good puddle must then be made in the Trench to the Elevation of the bottom of the pipes & allowed to grow stiff and the pipes bedded thereon so firm that no superstructure can move them – they must be flanch joints & secured together with screws and rings in the usual way which when done the whole of the Trench must be puddled up taking care that the puddle is made perfect at the bottom & sides of the pipes and more especially at the flanches.

There ought to be a piece of masonry at the inside orifice and guarded with some Bars of Iron to prevent wood or any other matter floating on the surface of the water when low getting into the pipes but especial care be taken that the end of the pipes do not rest upon any part of the stone work.

Another piece of masonry should be constructed at the lower end of the pipes – & similar care should be observed that the pipes at the end do not bear upon the stone.

It will become unnecessary to point out any plan as to how this is to be done as Mr Wood will be able to do that without my instructions only let it be simple & hid from the public eye as much as may be & the means of locking it up."

There's also a reference to the "offlet pipes" in the main body of the book that describes them as "18-inch cast-iron outlet pipes passing under the embankment to the twin feeder channels". There is a photograph of the outlet of one of the pipes by the author that shows an 1839 datestone, and an interesting reference to an incident in December 1964 when "floodwater over-topped the Todd Brook overflow weir to the extent of 3ft 4in. for 24 hours, damaging the spillway channel. This was rebuilt, but to prevent a recurrence a length of the dam itself was converted in 1970 into a large supplementary overflow spillway." – it is the latter spillway that failed in the recent incident. I'm no engineer but I'll see what I can do to incorporate some of this material into the article. Dave.Dunford (talk) 12:55, 12 September 2019 (UTC)

I've incorporated some of the material from the Boyes book in the article, but there's actually not much there to answer the original question about the outlet pipes posted above. They're mentioned but there's nothing about their capacity to drain the reservoir (at least not to this non-specialist). Dave.Dunford (talk) 19:57, 22 September 2019 (UTC)

Report on the 2019 incident is out

https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/872769/toddbrook-reservoir-independent-review-reporta.pdf

©Geni (talk) 16:01, 7 April 2020 (UTC)

Plans for long term upgrades submitted

https://www.bbc.co.uk/news/uk-england-derbyshire-58999203

Article doesn't provide much detail on them though.©Geni (talk) 23:48, 21 October 2021 (UTC)

But in full it's on the local authority website, as part of the planning application process. Now referenced in the article.--217.155.32.221 (talk) 11:13, 26 October 2021 (UTC)