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This channel has a load of information on water ways and how to design them.
Ah, OK. Not seen, or indeed looked for, many videos. Wikipedia states the reservoir is primarily a feeder for the canal so draining it for dam repairs isn't going to affect domestic water supply.
According to Sky News, Boris is now in Whaley Bridge. So if the dam is going to go, now would be a good time for it.
Edit: and on the BBC website, there's a local resident, presumably an expert in structural & civil engineering, watercourses and weather who's saying it's "health and safety gone mad" and he's not evacuating because "it won't break".
Part of me now wants his waterlogged body to be recovered from half way down the Mersey.
Can a civ eng tell us how likely ballast in shiny wet plastic bags is to slip when on the slopes of a dam compared to the same weight of unbagged ballast. It seems to me that the bags could act as a low friction plane.
If the aggregate wasn't bagged it would wash away. The weight of the bags and the way they interlock will be far in excess of the coefficient of friction so the bags ain't going anywhere soon.
That **** that said it's health and safety gone mad needs shooting as he clearly doesn't understand the risk not matter how small he faces. I agree that the emergency services shouldn't put themselves at risk to help people who won't help themselves however in the unlikely event of the dam breaching I suspect I'd try and help get folk out no matter how daft they've been.
They are trying to put some weight (400 tonnes) on the damaged side. If the water rises again (sunday is a risk) and it goes over the spillway again, then there will be a big problem.
Strictly speaking, it shouldn't go, but there could be weakness in the sub soil. All the spillway did was supposedly stop erosion - the amount of water going over just forced into gaps, shifted the panels and exposed the soil underneath, just like you do with sand castles when the tide comes in and build a dam.
You can't take the risk as it could potentially kill many folk in the village and smash half the town.
It's going to need draining, then the whole spillway replacing.
Jonwe. its better than doing nothing but probably only marginally. However none of the better options are available I would speculate. so should they carry on doing it for the moment until the folks working quietly in the background can get the water level down? Yes. It will have been cleared straight from no. 10.
Can a civ eng tell us how likely ballast in shiny wet plastic bags is to slip when on the slopes of a dam compared to the same weight of unbagged ballast. It seems to me that the bags could act as a low friction plane.
You know when the council / National Trust / Parks Authority resurface a bridleway by dumping tonnes of babyhead rocks all over it and two good storms later all those stones are at the bottom of the slope in a massive pile of rubble?
That's why it's bagged. 😉
For those oooing that dinky helicopter's agility, for something that weighs 22 tons the Chinook can be made to dance.
😉
11 tons U/L
11 tons max payload depending on varient , altitude etc
But this takes nothing away from the agility of the airframe. They are fitted with stress G monitors to ensure parameeters are not breached
some or all of the above may or may not be 100% accurate
Currently in WB helicopter has been flying since just after 4am, and it’s stll delivering some now at 22:40, front of the dam is natural stone, back concrete and grass. Looks like another long night while we wait.
Those guys can fly this afternoon they were taking about a minute of over hovering in one place as they exactly placed the bags.
Come on Boris, the folk of Whaley Bridge have suffered enough.
Boris the Ballast..
The weather forecast for Sunday (heavy rain) and most of next week, is not looking favourable for Whaley Bridge.
We need a good few weeks without rain now.
We have friends living on the hill on the other side of the dam, luckily they've had no trouble getting in and out of the town. Sitting in their garden they've been able to watch the chinook fly directly over their heads.
Boris Johnson - dam(ned) if he does dam(ned) if he doesn't, boom, boom.
No Chinook this morning just the noise from the pumps.
On the mildly plus side of things, the road closures around and in New Mills mean that various local people have discovered the ability to actually walk around town and - gawd help us - actually enjoy it. The relative lack of traffic and the nascent threat of impending doom makes for a slightly eerie atmosphere - the PC at the end of our road yesterday used the 'tsunami' word and someone on FB says they were told it would take 3 minutes for the water to hit New Mills were the dam to fail. I worry for the llamas and the policemen who risk death from excessive donated tea consumption.
Part of me now wants his waterlogged body to be recovered from half way down the Mersey.
I think it would be better if that didn't happen, mostly for the sake of the llamas.
It seems to me that the bags could act as a low friction plane.
They deform in and around and irregularities. If they put them on the concrete they'd soon be at the bottom. they're pretty effective as they flatten out and don't leave gaps underneath so the flow can't get underneath and lift/shift them. And the bag provides the erosion resistance.
Would the bags dissipate energy to some extent, like rock armour/ tetrapods at the bass of a cliff? This would then reduce/ prevent erosion of the dam if/ when water flows over the spill way again.
Edit: base
Probably but the main reason they're there is to sure up the hole to prevent further rapid erosion
They're allowing limited return to home for "essential reasons" but with an ongoing threat of immediate re-evacuation.
Weather forecast for Sunday looks shit. That said, the helicopter has been dropping aggregate at the various inflows to the res too so as to minimise further rainfall finding its way in.
That said, the helicopter has been dropping aggregate at the various inflows to the res too so as to minimise further rainfall finding its way in.
Won't the rivers just build up and overflow the mini dams, unless they're massive dams...
It's designed to slow the flow of water into it - won't stop it at all but it'll back it up enough to give the pumps a bit more leeway to cope.
Marple residents are getting leaflets now about the possibility of evacuating although the police are saying it's just a precaution at the moment and there aren't any plans to move people - it's just contingency planning.
About those bags. Yes they will help in the case of further overtopping but not by much I would imagine. However one of the modes of failure of an embankment dam is "rotational". Take a cross section through the dam, the weight of water in the reservoir is acting down on embankment. Sufficient mass is required in the exterior embankment to prevent a rotational failure (water side embankment pushed down, exterior embankment pushes up. My guess is the sandbags are there to put back mass lost in the washout.
slowoldman
Subscriber
About those bags. Yes they will help in the case of further overtopping but not by much I would imagine. However one of the modes of failure of an embankment dam is “rotational”. Take a cross section through the dam, the weight of water in the reservoir is acting down on embankment. Sufficient mass is required in the exterior embankment to prevent a rotational failure (water side embankment pushed down, exterior embankment pushes up. My guess is the sandbags are there to put back mass lost in the washout.
That's my assumption. The sandbags at the top should stop water from flowing down that side of the spillway. If it was to overflow onto the bags I doubt they'd last very long, look at what water did to the concrete (which was mostly flat and therefore lower drag).
I may have found a mountain biking angle on this.
"Fred Salmon, who runs the Bike Factory shop in the centre of the town, arrived with his van, hoping to bundle as many bicycles in the back as he could."
Here:
Not the Fred Salmon!!!!???
There are genuine concerns amongst locals about the threat of burglary and looting. It may not be a real threat but they are still very concerned.
A colleague worked on a test of the Chinook where they tried to recover a rib through the back door at sea.
Things learnt:
1) The British version is older and simpler than the American one. The American version has the underfloor space filled with computers and wiring, not good if you want to flood it with sea water.
2) There's fine line between deep enough to drive a rib in, and still being able to take off with in effect a bay full of water. To solve this they tied a rubber duck to a bit of string from the ceiling. When the duck hits the water you're deep enough.
Where does the water go, that’s being pumped out the reservoir? They’re presumably pumping out a considerable amount of water and it’s not as if they can store it in a few buckets until the dam is fixed.
Late to the thread, it looks to me like there has been some previous erosion(piping or washout) under the spillway previous to the it discharging. The discharge event managed to get under the slab and open away for turbulent water flow to enter exacerbating the erosion and causing a failure. It would be interesting to see the what the seepage rates were in the days previous and whether any solids were identified within the flows. I would also like to know whether there are any seepage control structures within the dam (downstream chimney filters and out let drains) to control fines within the seepage, all dams leak its just a matter of controlling the flows safely.
I build dams for a living.
Won’t the rivers just build up and overflow the mini dams, unless they’re massive dams…
The inlet becks don't feed directly into the reservoir, there's a conduit running round the edge of the reservoir that they feed into. Water only goes into the reservoir if the flow in the beck exceeds a certain amount.
@doordonot - I assume that the pumped water is being sent down the main slipway, or at least over it and into the outflow channel which then feeds into the river. So long as there's capacity in the river, i.e. it's not flooding then you're fine to do this.
The British version is older and simpler than the American one. The American version has the underfloor space filled with computers and wiring...
The UK-spec Chinooks have had a fair bit of electrical equipment in the underfloor spaces for a whole now, especially so since the HC2/2A variants were upgraded to HC4/5/6 and eventually 6A.
Where the UK-spec Chinooks differ from the vast majority of US-spec ones is that during the many upgrade programs a degree of marinisation has been included. Its salt water, rather than just water, which is the biggest threat to aircraft electronics. All Chinooks can land in fresh water.
There’s fine line between deep enough to drive a rib in...
RIBs aren't cleared to be carried internally with UK Chinooks as there is insufficient room. What can be (and is shown in footage) is a MIB (Medium Inflatable Boat), a flat and soft bottomed variant of the RIB.
The usual procedure 'post-swim' is to raise the nose for a short while to allow water to drain backwards out of the aircraft (to avoid lifting off with excessive extra weight) before transitioning into forward flight and climb away.
Not the Fred Salmon!!!!???
Yes, THE Fred Salmon. It's quite an area for cycling talent. Scott Dommett (yes, that other bloke from Dirt) lives just over the hill, Nick Craig is in Hayfield as is Rob Hayles.
Where does the water go, that’s being pumped out the reservoir?
Into the Goyt. That's why they're concerned about flooding downstream; it's been taking an extra 4 million litres an hour over and above what it normally takes plus of course the extra run-off from the hills after the storm. Levels going through New Mills dropped from their peak on Tuesday/Wednesday but it's still very high.
Yes the water being pumped out is going into the river. This seems to be coping at the moment. However with a forecast of rain for the next few days it's hard to say how the river will fair.
Last night in Marple (we are down river and canal from Whaley Bridge, Furness Vale and New Mills) there has been a large police presence. The police are there to knock on doors and let residents know that there could be a chance of being evacuated. Luckily we are high up from this and will be safe from flooding. Although I dread to think of the destruction it would cause lower down into the villages and towns in the rivers path.
Am worried about the 'sweetie factory', think of the children.
Swizzels is next to the canal but isn't the river much lower?
Torrside Brewery is next to Swizzels
😨
Hope Ratboy has got his spliffboat tied up nicely!
that video shows the problem much better than anything else I've seen. very scary stuff
Swizzels is next to the canal but isn’t the river much lower?
Torrside Brewery is next to Swizzels
😨
Yep, the canal sits way above river level. There are parts of New Mills that are much lower, but Love Hearts production is likely to be safe. I'm not altogether sure that's a good thing, but if that's the price we pay to God in return for brewery salvation, so be it.
I'm quietly pleased that Marple is now under martial law and probably ringed wth tanks, razor wire and minefields. A lot of very undesirable people live there and it's reassuring to know that they can't get out 🙂
Am worried about the ‘sweetie factory’, think of the children.
It'll be good for their dental, mental and physical health. That factory mostly seems to produce small tabs of hyper-compressed pure sugar flavoured with the sort of stuff normally found in toilet-freshening blocks - Parma Violets, Love Hearts, Refreshers, Drumsticks and Crystal Meth.
The River Sett levels have dropped considerably outside my house following last weeks heavy rain which is a good barometer for the natural state of the various water outlets. The Mersey wasn’t particularly high around Didsbury either, yesterday.
*cryptic message for Bunnyhop.*
Mellor Road and onto Dye House Lane or a massive detour and Hayfield Road and turn right opposite the Co-op are the only open routes by car.
No problems getting anywhere by bike though.
I’m quietly pleased that Marple is now under martial law and probably ringed wth tanks, razor wire and minefields. A lot of very undesirable people live there and it’s reassuring to know that they can’t get out
Ah cr@p I just bought a house there! On the nicer side of town though....
That factory mostly seems to produce small tabs of hyper-compressed pure sugar flavoured with the sort of stuff normally found in toilet-freshening blocks – Parma Violets, Love Hearts, Refreshers, Drumsticks and Crystal Meth.
I know, it's AMAZING isn't it?!
Love Hearts, Refreshers, Drumsticks and Crystal Meth.
Nooooooooooo!
I used to canoe down the canal with groups at work. Anyways good to get a sugar rush at the wee factory outlet...😜😜😜
It's not a wee factory but anyone tasting Parma Violets for the first time can be forgiven for making that assumption
Where are people getting these forecasts of torrential rain from? I’m on Weather.de and it looks like they’re forecasting about 6mm for the day.
I know it’s better to be safe and overestimate but it is quite a big difference. Obviously the ground is sodden so anything falling from the sky is pretty much run straight off.
Thanks Drac. No precipitation quantities though. However with the situation as it is and the local landscape I’m sure any rain will be more than unwanted.
Thunderstorms produce shits loads of rain in a few minutes which is worse than a gradual rain all day as it runs straight off the ground.
With hourly precipitation
It’s starting to look like there could be a lot of rain round here. The wind is picking up and it’s bringing rain clouds with it.
Thanks for the links above chaps. I get the fact that the nature of a thunderstorm massively exacerbates the problem, but they still show 5mm for the day and yet the local agencies are talking of numbers an order of magnitude higher. Just wondering if they are adding a worst possible case figure in there based on experience. Anyway, it’s outside my knowledge and all I can do is keep my fingers crossed for everyone up there.
Well, wherever all the water is going, it isn't having any real effect on the Goyt downstream
Attempt to post a link follows-
"https://flood-warning-information.service.gov.uk/station/5232"
There's a little helicopter buzzing around at the moment, and I haven't seen the Chinook at all today.
Monksie - thanks for the message. Glad to see you got home safely. nbt and myself rode back from New Mills on Strines road, it was bliss without drivers.
We went to visit BWD. The rather nice constable sitting at the bottom of his round had certainly had plenty of tea, also too many cakes by the sounds of it, but had he tasted the delights of the local sweetie factory? He seemed to be concerned about where to empty his tea filled bladder. You see mighty huge problems such as a dam bursting can bring along tiny little problems such as a constables bladder bursting and I don't mean a camelbac.
Yes I know the sweetie factory is above the Goyt, however it is just a foot or two under the canal and I believe if this dam bursts, the canal will get a large splosh of water causing a large wave or two.
I've been doing an anti rain dance.
and I believe if this dam bursts, the canal will get a large splosh of water causing a large wave or two.
I assume it's Marple Bridge and houses near Strines that have been warned, rather than Marple.
Still no rain, which is a good thing, but it's rather humid with lots of cloud.
Yes Marple Bridge, Strines and parts of Marple lower down from the canal and on the edge of the canal.
However the police have been giving out leaflets and knocking on doors in very minor event of some of marple having to evacuate.
We chatted to the police last night and they were very friendly while enjoying large amounts of curry.
We went to visit BWD. The rather nice constable sitting at the bottom of his round had certainly had plenty of tea, also too many cakes by the sounds of it, but had he tasted the delights of the local sweetie factory?
I reckon he's put on at least 20 kg today and is now physically incapable of leaving his car. He was eating an ice-pop when we passed him earlier. We could take him some Parma Violets later.
AMAZING
Truly.
The UK-spec Chinooks have had a fair bit of electrical equipment in the underfloor spaces for a whole now, especially so since the HC2/2A variants were upgraded to HC4/5/6 and eventually 6A.
It was infact the 2 Iirc.
Also something about having to use compost bags to build a dam across the back of the cockpit!
So the town is locked down, neighbours have put bins out for Monday collection, tad optimistic I think.....
THings seem to be progressing well now.
All that effort has paid off. 👍🏼
https://www.bbc.co.uk/news/uk-england-derbyshire-49231384
Probably a point of contention, but........
If the dam was built to keep the canal topped up rather than as water supply, is it worth fixing? Assuming that any fixing is going to be expensive then why not just decommission it? Then either accept that the canal will dry up in summer, or pump water back up the locks.
TINAS - bit of a bummer for those that live on the canal....
It's a working canal - Marple Lock Flight is a tourist attraction in itself, there's are marinas at Buxworth, Furness Vale, New Mills and Marple plus the canal hooks into Peak Forest Canal and runs right into Manchester. You'd kill the entire thing. Wildlife, businesses, people's homes.
It'd be cheaper and easier to repair the dam than try and decommission the entire canal!
We should be restoring and maintaining canals not closing as a dam had an issue.
TINAS – bit of a bummer for those that live on the canal….
Ducks you mean? No worries though, we could have a conceptual 'Garden Canal' and get it sponsored by multinational companies and send colossal amounts of public money on it before cancelling the thing. I know a PM who might be interested.
Police drone footage.
We should be restoring and maintaining canals not closing as a dam had an issue.
Risk Vs benefit.
On the one hand, the presumably large cost of restoring the dam and/or bringing it up to modern standards as appropriate and probably taking years anyway so the canal is going to have to survive without it for the short term. And still with residual risk of watery death.
Vs
Decommissioning the reservoir and feeding the canal from somewhere not available to the victorians (i.e. pump water back up the locks).
TINAS – bit of a bummer for those that live on the canal….
Look on the bright side, the canal and river trust wouldn't have to enforce continuous cruising anymore.
That’s an insane infrastructure put in place.
They're not mucking about, eh?
the canal and river trust wouldn’t have to enforce continuous cruising
You're thinking of Canal Street 😉
https://www.bbc.co.uk/news/uk-england-derbyshire-49247226
The Chinook was flying again most of this morning; it's brought in another 100 tonnes of so of aggregate.
Reported slippage of some bags, but its looking hopeful locals can go back soon. There has been social media calls for folk to visit Whaley and spend some money there to get business back up once safe - one of the ride groups I know could be planning a trip.
It's going to be one big repair job.
If you do go to Whaley to spend money, you could do worse than spend it in The Goyt, and say hello to Chaos the pub dog while you're there.
And the sausage rolls from the Bakehouse are a-mazing.
Yes and the pear tree cafe.
Would now be a good time to put on a town centre evening crit race?