Blaenau Festiniog Slate Waste?

[jones_bangor]

If we have access to large amounts of rock (and we do) we can potentially create thousands of square kilometres of additional land.

Boris Island etc?

 

[HSTEd]

Boris Island etc?

Boris Island would have to be a traditional landfill island rather than a polder, since a polder would cause a problem in that the plane woudl have to climb sufficiently to get over the dyke at the end of the runway.

But you could probably build an airport if the polder was sufficiently large that the 10-20m height of the dyke was irrelevent.

 

[Arglwydd Golau]

When the sea defences at Tywyn (Meirionydd) were strengthened a couple of years ago, some local granite was used:

'Around 60,000t of rock has been used in the scheme, with 40,000t sourced from nearby Penmaenmawr and the remainder coming from France and Norway. Two-thirds of the rock will be delivered by sea.' (from New Civil Engineer)

 

[Xenophon PCDGS]

When the sea defences at Tywyn (Meirionydd) were strengthened a couple of years ago, some local granite was used:-
'Around 60,000t of rock has been used in the scheme, with 40,000t sourced from nearby Penmaenmawr and the remainder coming from France and Norway. Two-thirds of the rock will be delivered by sea.' (from New Civil Engineer)

Thank you for that information. I knew that some of the Penmaenmawr Quarry output had been used in recent years in a marine situation.

 

[Gareth Marston]

Network Rail put a price tag of £250 million on upgrading the line to carry slate waste around 10 years ago - the frogs weren't boiling but being vaporized!

Clearly it was a price tag to kill off the project.

 

[Joseph_Locke]

Network Rail put a price tag of £250 million on upgrading the line to carry slate waste around 10 years ago - the frogs weren't boiling but being vaporized!

Clearly it was a price tag to kill off the project.

£250 million? From where (with link please) have you magicked up that figure?

(hint: I know for a documented fact that you are wrong).

 

[pablo]

Boris Island is dead! Let's get that fixed. It was out in the Thames Estuary.
The project he likes to be associated with now is Sir Norman Forster's Thames Hub, an extension north of the Isle of Grain into the Thames. Unfortunately he overlooked some sitting owners. Like an large LNG Importation Facility.
On the north bank of the river, west of Canvey Island, a new container port has just been created. That used a perimeter of rip-rap delivered by sea, and the infill was sand suction dredged from the adjacent Thames.
Glensanda Super quarry delivers a lot of stone to the Medway next to Thamesport, Foster Yeoman own both ends. I see a lot of railway ballast trains leaving there for the rest of the network. There's an enormous stockpile at Basford Hall, south of Crewe.
The slate waste is useful for infill; just depends on how much it costs to get it where it's wanted, and since it's still there, seems to answer it's own question.

 

[HSTEd]

The amount of material required for significant conventional "infill" islands would build a far larger polder.
The advent of geotextile tube-like structures for holding sand in place in dykes has drastically reduced the amount of riprap required to simple armouring.

 

[ChiefPlanner]

Network Rail put a price tag of £250 million on upgrading the line to carry slate waste around 10 years ago - the frogs weren't boiling but being vaporized!

Clearly it was a price tag to kill off the project.

That was outrageous ...I remember it well - funnily enough the BF line was then very well maintained due to it carrying odd nuclear loads for Trawsfynnydd. I suspect a more reasonable "cost" would apply today.

 

[Gareth Marston]

£250 million? From where (with link please) have you magicked up that figure?

(hint: I know for a documented fact that you are wrong).

sticks in my mind from my Rail Passenger Councils Wales days another poster recognizes it too, I well remember the incredulity it was met with but it was early days for NR back then when their remit was not rail expansion but get a grip on Railtrack mess and no more crashes.

 

[dysonsphere]

sticks in my mind from my Rail Passenger Councils Wales days another poster recognizes it too, I well remember the incredulity it was met with but it was early days for NR back then when their remit was not rail expansion but get a grip on Railtrack mess and no more crashes.

sounds familar I think it was someone saying "we don't really want to do this"

 

[LE Greys]

And, let's be honest, modifying sea defences in the next century or so may begin to look like rearranging the deck chairs on the Titanic. It might soon be the case that we have to build a whole new set of defences around 25ft above the current measured sea level, except in places such as London, then blast holes in the old ones.

 

[HSTEd]

And, let's be honest, modifying sea defences in the next century or so may begin to look like rearranging the deck chairs on the Titanic. It might soon be the case that we have to build a whole new set of defences around 25ft above the current measured sea level, except in places such as London, then blast holes in the old ones.

Surrendering thousands of square kilometres (as would be required to do this) would be completely untenable.
If we are going to have a 25ft rise in sea level then the best thing to do now is advance in ways that shorten the coastline.

Which means a dyke across the Thames, Severn and numerous other estuaries, with polders behind them.
(It may even be feasible at that time to build dykes that completely bridge the shallow parts of the southern North Sea (areas that were once part of Doggerland) as that could lead to less material being required than conventional dykes on each coast).

 

[Xenophon PCDGS]

Surrendering thousands of square kilometres (as would be required to do this) would be completely untenable. If we are going to have a 25ft rise in sea level then the best thing to do now is advance in ways that shorten the coastline.

Of course, we are still in the period of the landmass of Britain in slowly readjusting itself to the melting of the last ice sheet that covered most of Britain, where it is said that the southernmost part of Britain is slowly sinking. That matter has to be added to the scenario of the stated rise in sea level caused by certain factors.

 

[Joseph_Locke]

sticks in my mind from my Rail Passenger Councils Wales days another poster recognizes it too, I well remember the incredulity it was met with but it was early days for NR back then when their remit was not rail expansion but get a grip on Railtrack mess and no more crashes.

Well, the infrastructure-only figure Network Rail had in 2008 was a tenth of this, but at this point the promoter (Alfred MacAlpine) discovered a hole in their finances and withdrew. The official submission for funding had £46m (link)

So I still have no idea where you get £250m from? Are you sure you aren't confusing this with the more than reasonable costs for electrifying Borderlands?

 

[LE Greys]

Surrendering thousands of square kilometres (as would be required to do this) would be completely untenable.
If we are going to have a 25ft rise in sea level then the best thing to do now is advance in ways that shorten the coastline.

Which means a dyke across the Thames, Severn and numerous other estuaries, with polders behind them.
(It may even be feasible at that time to build dykes that completely bridge the shallow parts of the southern North Sea (areas that were once part of Doggerland) as that could lead to less material being required than conventional dykes on each coast).

I'm sure the country will think the same. It depends on which point the costs of this becomes untenable. Current politics is very good at kicking the can down the road, so they think 'the next government will deal with it' then continue to do this until a major storm surge over-tops the existing defences. Imagine that happens with the Thames Barrier and London floods in scenes resembling New Orleans. The first time, the city will be cleared out (imagine the nightmare of pumping out the Tube) with the defences heavily reinforced. Whether that involves advancing or retreating depends on how the government sees it at the time. However, it will probably happen again a few years later. Once it has happened three or four times, with people and businesses moving out because of it, there might well be preparations to evacuate the low-lying parts of the city for good.

The coastline has always been a dynamic system, it advances and retreats over prolonged periods of time. However, people are not very good at dealing with this, they tend to see lines on the map as fixed. Look at the way the Hungarian-Yugoslav border (now Hungarian-Croation) follows the old line of the Danube, not the new one as the uncontrolled river meanders, isolating small pockets of territory on the wrong side of the river.

 

[HSTEd]

I'm sure the country will think the same. It depends on which point the costs of this becomes untenable. Current politics is very good at kicking the can down the road, so they think 'the next government will deal with it' then continue to do this until a major storm surge over-tops the existing defences. Imagine that happens with the Thames Barrier and London floods in scenes resembling New Orleans. The first time, the city will be cleared out (imagine the nightmare of pumping out the Tube) with the defences heavily reinforced. Whether that involves advancing or retreating depends on how the government sees it at the time. However, it will probably happen again a few years later. Once it has happened three or four times, with people and businesses moving out because of it, there might well be preparations to evacuate the low-lying parts of the city for good.

There hasn't been a major dyke breach in the Netherlands since the Flood of '53, and the flood defences will likely be easily reinforceable against every projected sea level rise.

No reason we can't do the same.
(We can grab enough room for a few million extra people while we are at it as well).

The coastline has always been a dynamic system, it advances and retreats over prolonged periods of time. However, people are not very good at dealing with this, they tend to see lines on the map as fixed. Look at the way the Hungarian-Yugoslav border (now Hungarian-Croation) follows the old line of the Danube, not the new one as the uncontrolled river meanders, isolating small pockets of territory on the wrong side of the river.

That border looks very lightly populated by British standards, so it stands to reason that they will have less requirement to control the meandering of the rivers.

6m Sea level rise with all below sea level ground being surrendered would put the ECML at Peterborough within a mile of the coastline.

 

[Xenophon PCDGS]

In certain areas, the sea defences have been officially breached to allow the re-establishment of salt water meadowlands, which are said to be an aid in times of sea flood inundation.

 

[LE Greys]

There hasn't been a major dyke breach in the Netherlands since the Flood of '53, and the flood defences will likely be easily reinforceable against every projected sea level rise.

No reason we can't do the same.
(We can grab enough room for a few million extra people while we are at it as well).

Any more than a 25ft sea level rise, and the Dutch are in dire straits. The problem is, essentially, the higher you make the wall, the worse the consequences when it gets breached. Hence my earlier comment about rearranging the deck chairs on the Titanic. If sea levels decide to redefine themselves (and +25ft is a moderate rise, the +200ft levels of the late-Jurassic hothouse would make this look ridiculous). If we attempt to grab more land at progressively-deeper depths, if you see what I mean, somewhere it is all going to come apart on us. If we look at building defence in depth, in places that we can access rather than out to sea, then we stand a chance of preventing it from getting too bad. However, it means allowing for a shrinking country, not an expanding one. Of course, it would be far better not to have to plan for it in the first place.

That border looks very lightly populated by British standards, so it stands to reason that they will have less requirement to control the meandering of the rivers.

6m Sea level rise with all below sea level ground being surrendered would put the ECML at Peterborough within a mile of the coastline.

Much more, and the ECML is completely underwater. Restoring the fens to freshwater marsh would give some form of buffer zone (making Ely into an island once again) but would not do much for the people downstream of there. What we need to concentrate on is preventing the need for it in the first place rather than managing the retreat.
--- old post above --- --- new post below ---

In certain areas, the sea defences have been officially breached to allow the re-establishment of salt water meadowlands, which are said to be an aid in times of sea flood inundation.

This is what I mean by defence in depth, and a very good idea. The best British example is Wallsea Island, where Crossrail spoil is being used to create areas of free-flooding marshland (the idea being that if storm surges flood Wallsea, the Thames barrier will not be put under such strain) after moving the sea wall back three miles.

 

[HSTEd]

In certain areas, the sea defences have been officially breached to allow the re-establishment of salt water meadowlands, which are said to be an aid in times of sea flood inundation.

These protect against storm surges, which involve relatively small masses of water and last a relatively short period of time, meaning that distances can be an effective defence. (They are effectively useless against permenant sea level rise).

The lack of any calculation of the moral hazard involved in deliberately reducing food production also allows this to be presented as a "cheap solution".... additionally we do not currently have Malaria problems, if the climate continues to warm we will and marshlands will become public health issues again.

Any more than a 25ft sea level rise, and the Dutch are in dire straits. The problem is, essentially, the higher you make the wall, the worse the consequences when it gets breached. Hence my earlier comment about rearranging the deck chairs on the Titanic. If sea levels decide to redefine themselves (and +25ft is a moderate rise, the +200ft levels of the late-Jurassic hothouse would make this look ridiculous).

Most projections show a 25ft increase to the maximum concievable by about 2100-2200 in the absolute worst case scenario.
The only way that the 200ft sea level rise could come about is by the complete deglaciation of Antarctica, which is prevented in the current epoch by the fact that Antarctica remains entirely isolated from the global land mass system and is surrounded by a cold water current.
Short of a giant wall being constructed in the Magellan straits it will likely remain almost entirely intact for the forseeabe future. (It would take centuries to melt otherwise).

If we attempt to grab more land at progressively-deeper depths, if you see what I mean, somewhere it is all going to come apart on us.

There has not been a major dyke failure in the Netherlands since the flood's of '53.
The levees failed in New Orleans because of massive corruption in the maintenance of said levees which caused them to simply fall apart at the base.

If we look at building defence in depth, in places that we can access rather than out to sea, then we stand a chance of preventing it from getting too bad.

Defence in depth on land requires that we have somewhere to retreat to as the first line is given up, but retreating even a few miles along our coastline takes away a substantial fraction of Britains entire land area.
There is no way Britain could support that and hope to remain anywhere near food security. (We would go from being able to support our population given rationing to not being able to do so).

However, it means allowing for a shrinking country, not an expanding one. Of course, it would be far better not to have to plan for it in the first place.

Indeed it would, but we are in the world where we are going to have to plan for it, and advancing to reduce coastline length brings with it benefits of increased food production and the possibility of permitting larger, better homes to be produced without fighting NIMBYs continuously.

Much more, and the ECML is completely underwater. Restoring the fens to freshwater marsh would give some form of buffer zone (making Ely into an island once again) but would not do much for the people downstream of there. What we need to concentrate on is preventing the need for it in the first place rather than managing the retreat.

Buffer zones are only of significant use against Storm Surges, they are not really any use at all against Sea Level rise.
Additionally in either scenario (to a degree the 25ft one but certainly the nightmare 200ft one) we will probably not be able to count on anything coming out of the rest of the world but refugees.

Europe and North America will be alone, which means the days of being able to import food on functioning global markets will be long gone.
At which point food production becomes paramount.

If we are facing 200ft we should abandon plans to polder the North Sea and simply start construction on the largest dykes the world has ever known... at that point the only option becomes an attempt to build a insanely enormous dyke from Norway to France via Scotland, Ireland and Cornwall.
Then another across the Straits of Gibraltar and across the Suez Peninsula.

It would bankrupt Europe but the alternative is to starve.

But anyway.....

There is almost no chance that sea level rise can be significantly abated in this century, the course is locked in and it is frankly naive to believe otherwise.
Right now we need to plan mitigation and as far as I can see, dykes everywhere is the best way to achieve this for Europe.
--- old post above --- --- new post below ---

This is what I mean by defence in depth, and a very good idea. The best British example is Wallsea Island, where Crossrail spoil is being used to create areas of free-flooding marshland (the idea being that if storm surges flood Wallsea, the Thames barrier will not be put under such strain) after moving the sea wall back three miles.

Storm surges are not sea level rise.

Free flooding marshland is no defence against the latter, additionally attempting this on a massive scale causes serious food security, and soon public health, problems.

 

[Xenophon PCDGS]

With North Wales still in mind, how much colliery by-product waste accumulated to form what is now known (by me) as the Bersham Colliery Tip in the Wrexham area, which is said to be something that will take many years to clear. The objections raised did overturn the original decision not to remove the tip and I wonder if anyone knows the tonnage said to be there and of the use that the particular material will be suitable for.

Being a member of the National Trust, with the house and grounds of Erddig near to this area, this matter came back to mind during a recent visit there.

 

[LE Greys]

I think we need a new thread in General Discussion.

These protect against storm surges, which involve relatively small masses of water and last a relatively short period of time, meaning that distances can be an effective defence. (They are effectively useless against permenant sea level rise).

The lack of any calculation of the moral hazard involved in deliberately reducing food production also allows this to be presented as a "cheap solution".... additionally we do not currently have Malaria problems, if the climate continues to warm we will and marshlands will become public health issues again.

At the risk of a massive over-simplification, if the baseline sea level is higher, storm surges will also be higher. There is also the possibility that, with increased energy levels at sea because of higher sea surface temperatures, storms will be either fiercer or more frequent. I know I'm conflating the issue somewhat, but future coastal defences have to be planned around both a rising sea level and the highest predicted storm surge. If not, then it is hardly worth having them. This means a combination of different ideas for different places, I'm not suggesting we should evacuate London completely for instance.

What we have to answer is 'How much can we afford to lose and where?'. It might turn out that some areas are simply indefensible, or that the cost would be so high, even allowing for the loss of productive farmland, that we have to move the defences back to avoid things getting any worse. The Severn Estury and the Wash might be easier to defend by blocking off both (even an ardant conservationist like myself would be prepared to abandon large areas of wildlife habitat rather than risk famine). However, the 'long edge' of East Anglia might be a lot harder to defend.

Most projections show a 25ft increase to the maximum concievable by about 2100-2200 in the absolute worst case scenario.
The only way that the 200ft sea level rise could come about is by the complete deglaciation of Antarctica, which is prevented in the current epoch by the fact that Antarctica remains entirely isolated from the global land mass system and is surrounded by a cold water current.
Short of a giant wall being constructed in the Magellan straits it will likely remain almost entirely intact for the forseeabe future. (It would take centuries to melt otherwise).

The West Antarctic Ice Sheet currently appears to be receding, while the East Antarctic Ice Sheet (which is a heck of a lot bigger) is growing. From what I have read, the two appear to be balancing each other out. I'll avoid mentioning the +200ft prediction in the future, but it's worth remembering it's out there as a remote possibility. Still, let's consider the +25ft baseline increase as the basis for future planning.

There has not been a major dyke failure in the Netherlands since the flood's of '53.
The levees failed in New Orleans because of massive corruption in the maintenance of said levees which caused them to simply fall apart at the base.

That doesn't mean there won't ever be one again. The best available data currently suggest that the risk of failure is likely to increase in the future. I seriously don't want to be there when it happens!

Defence in depth on land requires that we have somewhere to retreat to as the first line is given up, but retreating even a few miles along our coastline takes away a substantial fraction of Britains entire land area.
There is no way Britain could support that and hope to remain anywhere near food security. (We would go from being able to support our population given rationing to not being able to do so).

Nevertheless, it is a choice we might well have to face this century. Human nature being what it is, we will put it off until a major storm surge (on top of a higher sea level) forces us to think about it. The higher the dykes, the bigger the catastrophe once they fail.

Indeed it would, but we are in the world where we are going to have to plan for it, and advancing to reduce coastline length brings with it benefits of increased food production and the possibility of permitting larger, better homes to be produced without fighting NIMBYs continuously.

That may work in some areas, but not necessarily everywhere.

Buffer zones are only of significant use against Storm Surges, they are not really any use at all against Sea Level rise.
Additionally in either scenario (to a degree the 25ft one but certainly the nightmare 200ft one) we will probably not be able to count on anything coming out of the rest of the world but refugees.

Europe and North America will be alone, which means the days of being able to import food on functioning global markets will be long gone.
At which point food production becomes paramount.

If we are facing 200ft we should abandon plans to polder the North Sea and simply start construction on the largest dykes the world has ever known... at that point the only option becomes an attempt to build a insanely enormous dyke from Norway to France via Scotland, Ireland and Cornwall.
Then another across the Straits of Gibraltar and across the Suez Peninsula.

It would bankrupt Europe but the alternative is to starve.

But anyway.....

There is almost no chance that sea level rise can be significantly abated in this century, the course is locked in and it is frankly naive to believe otherwise.
Right now we need to plan mitigation and as far as I can see, dykes everywhere is the best way to achieve this for Europe.

It is equally naive to think that we can continue to wall out the sea for ever. Europe has some tough choices over the next century or two, you've just outlined one of them.

Storm surges are not sea level rise.

Free flooding marshland is no defence against the latter, additionally attempting this on a massive scale causes serious food security, and soon public health, problems.

See above.