[Closed] Photo: Thames Barrier holding back tidal surge.

Great insights PR. I remember some report on an emergency you attended that was similarly fascinating

I was asked about that this week, seems like a long time ago, it's still not fixed permanently, our temporary 'repair' is still holding fast though.

[url= http://singletrackworld.com/forum/topic/working-for-the-environment-agency-and-how-my-weekend-escalated-somewhat ]That was just over a year ago, it's been calmer this year, so far...[/url]

Well, it's certainly an impressive sight. But there are so many barriers and diversion systems down the river to make any visit fascinating.

I do recommend folks ride the route I mentioned, you may think the East Thames is grim, it certainly has its odd bit at the back end of "Dagenham on T'River" but the shipping container port at Tilbury has to be see to be believed, but before that you've got Rainham RSPB Nature reserve which is lowland marshes.. then the landscape changes to open marshes and quiet nature.. until you get to SarfEnd.

Best thread in ages.

Thames Barrier = titanium loveliness 🙂

I think we can all agree that pictonroad has won the interwebz for today.
Bravo!

I would agree with many "best thread in ages" as an engineer its so nice to see others work areas 🙂
Never mind the chain (SEDIS/SACHS?) that sprocket is a thing of beauty.

Though I have to say the cable runs and the termination section of that panel with the disk brake in would incur my wrath & working in an electrical panel with a very melty Hi-Viz & no hat/eyewear would get you kicked off my site 😮

The squiggly bars (on the open mesh flooring) not lining through gets my OCD every time

I still have dam busters theme in my head with that first view... 😉

Fascinating stuff - I regularly ride between Greenwich and Dartford and keep meaning to do a tour inside the Thames barrier.

Hopefully when the day comes when a tsunami or suchlike sweeps down the Thames and the barrier is closed to protect those the west, I live sufficient!y far enough from the river not to get flooded.

The UK's second largest barrier is up north...

I bet that powerlink is a bugger to undo. That chain can be used by any Nicolai Mojo owners

I used to cycle next to the Dartford barrier regularly a few years ago .
always wondered what it was .

its a great shot indeedy although i saw it last month on facebook and there's some question about how recently it was taken as the trees look suspiciously in full bloom.

Does it matter? Probably not

Are you talking about the cycle route on the north or south side of the Thames? Sounds like the north side

I've done a bit of each, but not the full length. The South side from Greenwich towards Thamesmead feels surprisingly quiet and deserted

CaptainFlashheart - Member
I think we can all agree that pictonroad has won the interwebz for today.
Bravo!

Photo released last month, like you, I suspect it was taken last year. (EA didn't take it) The Barrier was closed for the storm surge in late January though so it would look the same but less sunny. 😉

The original photo is spectacular but I need help. When is the barrier raised and why is there no build up of water on the upstream side?
EDIT: And what's the height difference between levels?

The North Side, the South goes down the Thames to Chatham.. another route I plan to do one day.

Anyway..

Picktonroad has a proper job, we just play at what we do..

At what point might rising sea levels cause a problem?

[img] [/img]

In 2009 there was a UK Climate Impact Projections report that specifically looked at the Thames Barrier as a case study, and the above figures is the sort of decision making tree for the implications of sea level rise on the future of the Thames barrier. Current best estimate based on this report is sea-level rise in the Thames estuary of 0.2-0.88 m by 2100. However there are two components which add complication 1) the unknown magnitude and occurrence of future storm surges, which are the main reason the barrier has to be closed (as above) which will be in addition to the background sea-level rise 2) the relative unknown stability of the Antarctic ice sheet. UKCIP worse case scenario (H++) allows for up to 2.6 m of sea level rise in case of ice sheet instability, at which point a new barrier would certainly need to be built, with suitable lead in time. That last point is an area of quite major debate.

We are working on trying to better understand ice sheet response to warmer climates, but it is still uncertain to a point, which does make decision making by the government on large infrastructure projects like this a bit more challenging, for all involved.

Thanks for the photos pictonroad - they are awesome 🙂

Great thread,it's what's so good about this forum. Pictonroad thanks for your input,very informative.

What happens in the scenario where the barrier has to be shut to keep a tidal surge out of London at the same time as unusually high levels of water come downstream from Windsor direction?

I remember Egham and Staines flooding a couple of years ago which IIRC they've not done for 25 years. Also Cleopatra's Needle on Embankment having waves lapping at its base last year - first time I remember that happening in 15 years. I believe the water table is still very high so it may not take a massive storm to cause a repeat.

When you come across Battersea Bridge on the train and look at all the new flats going up on Battersea Power Station it doesn't half look like the ground floor flats would be underwater if the tide ever overcame the top of the shoring on the south bank. But developers would never build thousands of luxury flats on land at risk of a flood, would they... 😯

Brooess - the groundwater levels are not high at all at the moment. In fact some of the water companies were looking t drought issues for next summer if we continued to have the prolonged lack of rain in the South East. Hopefully we have now had normal service being resumed and the aquifers fill up again, as a lot of places rely on water storage in the ground rather than reservoirs. It will take a few months to get back to the situation of 2013/14 and there is no way you would every get me saying it will not happen.

As for the operation of the barrier during flood events, as somebody said earlier, you can operate it so that you shut it at low tide during a flood event and have a very substantial amount of storage in the river itself. The maximum flow up at Windsor was around 400 meters cubed a second (400,000 litres) so you can work out how much will back up in the reach above the barrier. The surveys that we have allow us to estimate the volumes coming in and the time of the tides so we know when to close the barrier and still allow the water to be stored in the river during that time and not flood London.

On a side issue there is already work underway to replace the barrier (next 20 years) and the levels that we have to protect against will be considerably higher than the design heights at the moment. As Pictonroad said it involves much more than just the barrier across the Thames. All of the estuary gates and infrastructure has to be raised as well so it is a very large undertaking. It is still a very cool bit of engineering though and I love going under there occasionally.

Judging by his email, Manton is a Mr Roberts, we worked together a few years ago. He's an actual expert, I'm just a Project Manager, I apologise profusely to him for all my inaccuracies. It's a post-expert world now don't you know.

The problem with climate change is not just the levels, it's the frequency of close conditions. It's something of the order of the Thames Barrier's annual frequency of closure now is the same as its 10yr operation level at installation.

What a great and interesting thread, thank you pictonroad and others who contributed.

I'd quite like to go on a tour that shows how the whole system works (main barrier and the other barriers and any other supporting bits).

let it go and flood London. wahoooooooo. wash all the filth away...

Guilty as charged Mr K (I think from a bit of we stalking). Actually that stat about the closure rate for the design life is now the big issue. I can't quite remember the exact numbers but it was something like the barrier was closed more is the winter of 2013/14 than it was envisaged it would close in the 25 year design life.

On a side issue there is already work underway to replace the barrier (next 20 years) and the levels that we have to protect against will be considerably higher than the design heights at the moment.

That closure rate issue is very interesting.

That's me.

No one has decided, new studies and guidance is carried out all the time. Reading between the lines of the current guidance pretty much everyone agrees the current infrastructure will do until 2040. Problem is, for a project that size you really need to start thinking about a replacement now, like really planning and having a permanent team in place dedicated to this one outcome.

So where the water in the river go?

I often wondered about this. I'd assumed that the river water simply backs up against a higher sea at high tide, but this is not the case. When the tide comes in, it comes *into* London. So the river flows backwards very vigorously as seawater flows into it. This confused the crap out of me when I first started going to London as it looked like I was on the other side of the river to where I thought I was, judging by river flow.

So there is enough capacity in the river channel normally to hold all the water coming down stream AND the water coming in from the sea. So if you close the barrier for 12 hours, the river channel only has to hold the water coming downstream and nothing from the sea direction, which it can easily do.

If London did flood the effects would probably sink the whole country.

Every important business is probably headquartered there. All the banks, pensions, data centres etc.

Flood London and you will probably find the supermarkets cant take your card for payment. The cashpoint machine in your town wont work. The "Cloud" where the internet now lives will stop, its not actually in a cloud.

Flood London and you will probably find the supermarkets cant take your card for payment. The cashpoint machine in your town wont work. The "Cloud" where the internet now lives will stop, its not actually in a cloud.

Actually no, cos these things are planned for - but you are right that flooding London would cause havoc. The sheer cost of cleanup would be far greater than anywhere else. If nothing else, your insurance premiums would probably have to go up quite a bit.

Great thread!

Not wanting to derail the thread too much, but it's vaguely linked if folks want to have a gander - where is the path on the North side?

I've done some of the North on the London to Southend BHF ride, but that's the bit near Rainham Marshes I think. Strava heatmap shows that extending towards Tilbury, but nothing further in towards Central London...?

havoc includes flooding the underground...

Max. havoc scenario I've come across is the Barrier being overtopped and the storm surge causing/being accompanied by major a fuel/oil retention failure in the at Shell Haven /Coryton refinery tank farm. High winds and water bringing floating, fiery death into central London.

One for scotroutes, there! 'cept the refineries shut down years ago, not even sure if there's any tank farms there now. There are a couple over on Canvey Island, though.

Flood London and you will probably find the supermarkets cant take your card for payment. The cashpoint machine in your town wont work. The "Cloud" where the internet now lives will stop, its not actually in a cloud.

Actually no, cos these things are planned for

Agreed - Visa's data centres for e.g. are out of town even though Head Office is in central London. I imagine that all critical infrastructure is sited and defended or at least risk-managed for such events, or being planned to be moved or defended according to climate change forecasts

OP - bit of a cheeky ask but I sense enough curiosity on this thread for an STW-guided tour of the barrier. I'd certainly be interested - the risk of London being flooded fascinates me - the risk to the UK economy overall being so high that I'm assuming a huge amount of attention's being paid to ensure it doesn't happen...

Would you be happy to do that one weekend? I'm happy to sort out a meeting place somewhere appropriate and we can ride up from central London to the barrier for you to show us how it all works.
If anyone knows of a suitable quiet route that would be helpful. I could try and sort out something using Google Maps but an existing known route would be less of a fuss...

Shell Haven /Coryton refinery

don't worry, not much left there - tis all being bulldozed as we speak.

I've run around the flood barriers over on the flood plans near the refinery, there's quite a complex of them over there.

At risk in the Tidal Thames floodplain (in 2008, will be higher now):

1.25 million residents
600.000 homes
40,00 commercial and industrial sites
400 schools, 16 hospital, 8 power stations
167km of rail, 35 tube stations, 51 rail stations
300km of A road

I haven't assigned values because it will send up the signal for Binners to turn the thread into a North vs South but you can see how a strong economic case can be made for investment in flood protection.

working in an electrical panel with a very melty Hi-Viz & no hat/eyewear

If it goes wrong in the panel the clothing choices will be the least of the sparky's problems. Been there seen that, it wasn't pretty. Clothing was ok but the skin from contact to earth was in a bad way. Also my first H&S visit a baptism of fire literally. Don't use your water-pump pliers to manipulate SWA three-phase in a live panel kids. It's not big nor clever.

OP - bit of a cheeky ask but I sense enough curiosity on this thread for an STW-guided tour of the barrier.

I could have got you round on the sly a few years ago, it would be too much of saga now, it's on a high level of lockdown.

There are still tours (I think? there were a couple of years ago anyway) given through the Institute of Civil Engineers and similar institutes, that would be your best bet.

I could wangle a couple of people round the Dartford Creek Barrier but you'd have to be 'working'. 😉

you'd have to be 'working

I'm sure I can rustle up a clipboard from somewhere! 🙂

rickmeister - Member
Looks like a bit of low water beach riding to be had, RH side of the barrier...

[img][url= https://c1.staticflickr.com/6/5759/23680749249_06bbb4b665_b.jp g" target="_blank">https://c1.staticflickr.com/6/5759/23680749249_06bbb4b665_b.jp g"/> [/img][/url][url= https://flic.kr/p/C5A2Ja ]2015-12-29_05-42-10[/url] by [url= https://www.flickr.com/photos/martinddd/ ]martinddd[/url], on Flickr[/img]

Tis doable.

Max. havoc scenario I've come across is the Barrier being overtopped and the storm surge causing/being accompanied by major a fuel/oil retention failure in the at Shell Haven /Coryton refinery tank farm. High winds and water bringing floating, fiery death into central London.

Are you thinking of a pretty bad book?

[img] [/img]

There are still tours (I think? there were a couple of years ago anyway) given through the Institute of Civil Engineers and similar institutes, that would be your best bet.

I imagine that all critical infrastructure is sited and defended or at least risk-managed for such events

It is. Visa's operations are treated as national infrastructure despite being privately owned. Most banks have data centers sited in specifically chosen places, and they have more than one in case one gets blown up or wiped out in some catastrophe. Same for all sorts of infrastructure.

Flood London and you will probably find the supermarkets cant take your card for payment. The cashpoint machine in your town wont work. The "Cloud" where the internet now lives will stop, its not actually in a cloud.

Actually no, cos these things are planned for

Agreed - Visa's data centres for e.g. are out of town even though Head Office is in central London. I imagine that all critical infrastructure is sited and defended or at least risk-managed for such events, or being planned to be moved or defended according to climate change forecasts

From the little that I have seen, a major weakness of the resilience and disaster recovery planning for a major London flood, is the fact that much of our critical infrastructure and services etc. is owned by hundreds/thousands of different private companies, in addition to the publically owned and managed parts (which are themselves fragmented between different levels of government and different departments).

A huge difficulty in disaster and resilience planning for a massive widescale event like a London flood, is that it is impossible to predict/model the consequences on all these different services and infrastructure. I have seen commercial modelling of a large London flood where the consultants only considered the damage to their large corporate customer's sites in isolation, and in quantifying the effects (both cost and speed to recover), they effectively assumed the rest of London was undamaged, when in reality the damage to the rest of London would affect the business far more than the physical damage to its own sites.

A classic simple example of this was the 7/7 bombing: all the disaster plans for the businesses in the City relied on the mobile phone network for communications in the event of landline failure, but the emergency services seized most of the mobile bandwith, and as a result many people could not use their mobiles.