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The sheet piling comes along one side of the railway .... gap for track then restarts as a concrete wall at same level as steel piling.
But what about the gap ?
Restricted flow in a flood, so OK (Thames barrier like) ? Railway track ramp to be installed at a later date ? Temp wall across the track at high tide ?
Seems odd.
https://www.asea-flood-ecology.co.uk/
The railway is quite a bit higher than the surrounding ground level. I'd expect something fancy up to close to the rails, if it's anything like our flood defences, which are now more expensive then moving all affected properties to higher ground.
What's the bridge on the other side? Are they going to tie in the two walls to that?
Working with Network Rail. *shudders*.
Not many defences cross railway lines, we've just put one in Newhaven. Had to reroute all the power, install a below ground cut off channel for the water and a sliding 'skirt' across the tracks. Design, engineering and operational saga but you can't move the railway or persuade the sea to go elsewhere. 🤷♂️
I don't know the specific job but there's no way it would be designed as a gap as the concentration of flow at one point would erode the line.
It may have a demountable barrier for higher order events. Network rail don't like stopping services irrespective of flood risk so you can guarantee whatever the solution it's taken years to get to and involved much gnashing of teeth.
It looks like the piling is going uphill, perhaps the flood level protection is lower than the tracks. The defences near me are like that, the lowest point is the level they want to protect, and then the wall starts to rise with the pavement and then stops where open railings take over.
There’s a drainage ditch running past the Suez recycling place on the other side, I wonder how that’s going to be dealt with as well.
Just zoomed out to look at the wider area, including Royal Portbury, where I used to pick up and drop cars for BCA, and spotted where Cazoo’s prep place is, not all that far away, it seems.
Haven’t been down that way for ages, I’ll have to take a run down there and have a walk along the Severn Way, I’ve walked part of it further north.
The drainage ditch will get a wall across it and a no return valve, most like a rubbish fishtail valve to allow trickles through rather than a flap valve that tend to get stuck open or shut.
Not sure about the wall. network rail won't like two things about it.
1. Increased scour as all the water that should hit the flood plain is now channelled under the structure.
2. If the flood levels get that high there will by a hydraulic load on the side of the deck.
So it might be that the flood level is considerably lower than the wall top. It would probably be 600mm below at a minimum to have sufficient freeboard.
OP, you're not missing something: if you read the timeline sheet it says "Future phases of project – Upgrading of the railway embankment will be integrated with Network Rail or Metrowest plans at a later date"
So a case of a new bridge (or heavily altered abutments) /raised railway embankment/additional drainage.
Pictonroad would likely be able to explain the planning intricacies of Network Rail/Great British Railways infrastructure projects more but this particular one probably has to be scheduled into the next control period.
Cos, you know, the Severn Bore and Tides works to schedules. Climate change induced sea level rise and storm surges, less so...8-/
Pictonroad would likely be able to explain the planning intricacies of Network Rail/Great British Railways infrastructure projects
Nope, no one can, not even Network rail. It's like an enigma wrapped inside a cluster ****. Even doing work for them is hard going, add a lack of any reason for network rail to be helpful.... And god it's tedious.
They'll likely tie the end of the wall to the abutment of the bridge, with an angle section to reduce local scour.
Also in my early post it should say rubber not rubbish.
I had a brief encounter (site meeting) with Network Rail about repairing a blocked telecoms duct near a level crossing.
After a few back and forths with increasing requirements we seemed to be going backwards. I gave up and we went for a much more complicated and disruptive option using our existing cables which also meant we were not able to repair the duct for future use.
Network Rail suddenly got very inquisitive about how we were going about it despite assurances we were not working within 50 metres of the crossing or using any traffic control within 200 metres. I think they were disappointed as it's good cash flow for them, although I've since heard the cost can drop wildly if you negotiate.
Thanks guys. Looks like a seawall with a load of gaps 🙂
Top planning.
I suppose the trains on the Severn Beach line will look likethis 😉 Especially on a high tide 🙂
Possibly somethng like this ?
All seawalls have lots of gaps. You'll have a bit of a wet patch on the land side otherwise.
I’d expect something fancy up to close to the rails, if it’s anything like our flood defences, which are now more expensive then moving all affected properties to higher ground.
Yep they can be. Abandonment is controversial for obvious reasons so there are alot of weightings considered not just the value, which would obviously be weighted in favour of large/expensive/wealthy areas. We did most of the borders flood studies. It's an interesting subject, the economics of flood defence wouldn't like to be the guy delivering the news to residents, he sits two desks away from me!
Meanwhile, on the other side of the country…
The map is worth a look, that whole stretch of the Severn Estuary/Bristol Channel is clearly under threat, but nothing like Norfolk and Cambridgeshire across from the Wash. One of my best friends lives out there, she owns a narrowboat and has a stretch of canal running past the end of her road! She might need it at some point in the future.
The ASEA site has a detailed plan and timeline which shows the sheet piled wall, a new drainage outlet and short concrete retaining wall (all of which is shown on the photo). Nothing is shown across the track and funding bodies do not include NR. There is the additional problem of the crossing for the seven way (the rubber panels across the track). That would need to be factored into any flood defence. Could be this location is one for the future when between the local authority, network rail and any other stakeholders figure out what to do.