Why build a wall and pump? Just start dumping rocks at the center in the planned volume or a few % more to account for subsidence at the edges to the known angle of repose. Voila, your land mass for less. And it would be quicker - probably done by next April Fools' Day.
Thanks for the suggestion - we did consider this, but our current understanding is that just dumping material (during current much smaller scale land reclamation projects) tends to leave the reclaimed land highly vulnerable to erosion, meaning that the land would quickly shrink (while the referenced Dutch wall should last for >200 years). Specifically, extrapolating from the rate of erosion between Flamborough and Spurn Heads (https://bigthink.com/strange-maps/a-map-of-europes-fastest-eroding-coast/ - and the soil here would likely be even weaker) the island would shrink by ~1.5%/year, and presumably faster at the surface, which seems much too high for stability. We do agree that the wall section assembly would likely form most of the construction time though.
Wel, there must be a reason the Dutch and the Venetians opted for a "wall" instead of a long breakwater of the type that has protected Buffalo's harbor from winter's fury on Lake Erie for 150 years, with maintenance, so probably you're right. Pictures of the Dutch wall, though, seem to indicate that a lot of it looks like breakwater.
If your land's made of demolished Welsh mountains (reminds me of the beautiful karst mountains being taken down in the Yangshuo region of China), though, it seems easy enough to make sure the edges of Doggerbank are made of large rocks, not the soft clay that's eroding between Flamborough and Spurn. One also wonders about the relative cost of wall+pumping vs retaining one work crew to dump around the edges perpetually to counteract the erosion you foresee. Or about the propriety of dumping first, then building the wall around the edges of what you've dumped. No pumping, shallower foundations, cheaper wall. Anyway, an interesting thought experiment. Who knows what will be possible once energy's too cheap to meter?
I don't understand why you need to fill in crushed rock or sand. Just build the wall and be done? the entire area would be below sea level but that's not unheard of: The lowest spot in the Netherlands being nearly 7 m below sea level.
Guessing you'd have to keep pumping anyway. A question is how long it would take for rain input to turn water bodies from salt- to freshwater.
PS Understandable but shame to have it as an April Fool's thing. Seems sensible to me. An instance of pushback against innovation starvation (Neal Stephenson's phrase).
Under the cost estimates we have in the article, it would be substantially cheaper to fill it in - cost of doing so is only 9% of the total cost, compared to 12% from merely having the pumps active for 100 days - of which half is the cost of the backflow during that length of time. We now think our backflow estimates were probably too high (especially as rain seems to be a substantial portion of the water ingress in similar projects), but it remains the case that it seems that managing to avoid pumping altogether after filling has begun would probably be cheaper on net.
If backflow is lower that's great news for wanting fewer pumps that you'd never need to use again (unless maybe for a next project) after the intial drainage phase. Don't quite see though how the optimization works out to want to do it so quick: My logic says as long as you pump faster than backflow it'll eventually empty out. So the minimum number of pumps to maintain a narrow surplus should be optimal? Understood its *desirable* to not let it take too long.
We include electricity costs in the cost of pumping at current UK market prices (due to proximity to wind we might be able to do this slightly cheaper), so it does minimise total expenses to do it at the calculated rate (and these do end up as a substantial portion of the total at the optimal choice). Optimal rate will necessarily be slightly faster than this due to including the delay on benefits from longer construction times etc.
Yup, gotcha. Also thought if the planned Dogger Bank wind farm was fully operational at construction start proximity might facilitate deals to use excess capacity the grid can't handle when there is a lot of wind across the region to lower power cost even more. Anyway, again, great piece. I really do wonder why it feels fantastical when it checks out as a financial proposal in terms of ROI and represents a credible nuts & bolts plan to alleviate population pressure & massively stimulate growth across the board, not just particular industries.
Pumping while getting paid is nice of course—but then the question arises whether to keep pumping at a higher price or wait for the next oversupply window to then compensate with negative cost for back seepage that happened while pumps were stalled? Wind prediction enters the picture!
You should take a look at the Metabolist plans for Tokyo Bay - no need to create a whole new massive island. Also water ways are very efficient means of transportation.
You'd have to deal with tsunamis, which is likely what destroyed the original Doggerland at the end of the last large-scale glaciation. If you have it be on average a couple dozen meters below sea level, a fairly small tsunami caused by something happening in Iceland (landslides or pyroclastic flows caused by volcanoes are a fairly frequent source of big tsunamis) could swamp the entire region. A nontrivial tsunami may only happen every couple hundred years in northern Europe, but if one happens and you haven't designed around dealing with it, millions die here.
If the land is filled at or a bit above sea level, a 10+ meter tsunami would still cause largish devastation along the immediate coast facing the tsunami's wash, but wouldn't flood the entire zone and kill millions. And your original sea-wall may be left in place and built up a bit bigger to handle tsunamis and large storm-surges.
I like this idea. I think it gets cheaper if you consider that lots of parts of the UK (and possibly other bits of Europe) would be interested in losing very large volumes of land in order to create new lake districts, preferably of the freshwater variety.
Also, have you considered building the city round canals, like Venice?
“UK wages compared to 1998 Korean ones, which are ~86% higher than UK wages.” Think you meant that UK wages today are 86% higher than 1998 Korean wages.
Apologies, we did make an order of magnitude error with the calculations here - we would probably need to avoid this step and just place the volume of rock we discussed at the edges to prevent backflow, or perhaps cover the entire area with a waterproof coating. This shouldn't affect the rest of the calculations though - provided we can prevent backflow Dogger Bank should remain fully habitable.
Why build a wall and pump? Just start dumping rocks at the center in the planned volume or a few % more to account for subsidence at the edges to the known angle of repose. Voila, your land mass for less. And it would be quicker - probably done by next April Fools' Day.
Thanks for the suggestion - we did consider this, but our current understanding is that just dumping material (during current much smaller scale land reclamation projects) tends to leave the reclaimed land highly vulnerable to erosion, meaning that the land would quickly shrink (while the referenced Dutch wall should last for >200 years). Specifically, extrapolating from the rate of erosion between Flamborough and Spurn Heads (https://bigthink.com/strange-maps/a-map-of-europes-fastest-eroding-coast/ - and the soil here would likely be even weaker) the island would shrink by ~1.5%/year, and presumably faster at the surface, which seems much too high for stability. We do agree that the wall section assembly would likely form most of the construction time though.
Wel, there must be a reason the Dutch and the Venetians opted for a "wall" instead of a long breakwater of the type that has protected Buffalo's harbor from winter's fury on Lake Erie for 150 years, with maintenance, so probably you're right. Pictures of the Dutch wall, though, seem to indicate that a lot of it looks like breakwater.
If your land's made of demolished Welsh mountains (reminds me of the beautiful karst mountains being taken down in the Yangshuo region of China), though, it seems easy enough to make sure the edges of Doggerbank are made of large rocks, not the soft clay that's eroding between Flamborough and Spurn. One also wonders about the relative cost of wall+pumping vs retaining one work crew to dump around the edges perpetually to counteract the erosion you foresee. Or about the propriety of dumping first, then building the wall around the edges of what you've dumped. No pumping, shallower foundations, cheaper wall. Anyway, an interesting thought experiment. Who knows what will be possible once energy's too cheap to meter?
I don't understand why you need to fill in crushed rock or sand. Just build the wall and be done? the entire area would be below sea level but that's not unheard of: The lowest spot in the Netherlands being nearly 7 m below sea level.
Guessing you'd have to keep pumping anyway. A question is how long it would take for rain input to turn water bodies from salt- to freshwater.
PS Understandable but shame to have it as an April Fool's thing. Seems sensible to me. An instance of pushback against innovation starvation (Neal Stephenson's phrase).
Under the cost estimates we have in the article, it would be substantially cheaper to fill it in - cost of doing so is only 9% of the total cost, compared to 12% from merely having the pumps active for 100 days - of which half is the cost of the backflow during that length of time. We now think our backflow estimates were probably too high (especially as rain seems to be a substantial portion of the water ingress in similar projects), but it remains the case that it seems that managing to avoid pumping altogether after filling has begun would probably be cheaper on net.
Thanks, great explanation!
If backflow is lower that's great news for wanting fewer pumps that you'd never need to use again (unless maybe for a next project) after the intial drainage phase. Don't quite see though how the optimization works out to want to do it so quick: My logic says as long as you pump faster than backflow it'll eventually empty out. So the minimum number of pumps to maintain a narrow surplus should be optimal? Understood its *desirable* to not let it take too long.
We include electricity costs in the cost of pumping at current UK market prices (due to proximity to wind we might be able to do this slightly cheaper), so it does minimise total expenses to do it at the calculated rate (and these do end up as a substantial portion of the total at the optimal choice). Optimal rate will necessarily be slightly faster than this due to including the delay on benefits from longer construction times etc.
Yup, gotcha. Also thought if the planned Dogger Bank wind farm was fully operational at construction start proximity might facilitate deals to use excess capacity the grid can't handle when there is a lot of wind across the region to lower power cost even more. Anyway, again, great piece. I really do wonder why it feels fantastical when it checks out as a financial proposal in terms of ROI and represents a credible nuts & bolts plan to alleviate population pressure & massively stimulate growth across the board, not just particular industries.
Actually negative power prices makes the optimization problem even more fun: https://www.theguardian.com/environment/2023/may/29/weather-tracker-power-prices-dip-to-negative-in-europe-amid-clean-energy-boost
Pumping while getting paid is nice of course—but then the question arises whether to keep pumping at a higher price or wait for the next oversupply window to then compensate with negative cost for back seepage that happened while pumps were stalled? Wind prediction enters the picture!
You should take a look at the Metabolist plans for Tokyo Bay - no need to create a whole new massive island. Also water ways are very efficient means of transportation.
https://en.wikipedia.org/wiki/Metabolism_(architecture)
You'd have to deal with tsunamis, which is likely what destroyed the original Doggerland at the end of the last large-scale glaciation. If you have it be on average a couple dozen meters below sea level, a fairly small tsunami caused by something happening in Iceland (landslides or pyroclastic flows caused by volcanoes are a fairly frequent source of big tsunamis) could swamp the entire region. A nontrivial tsunami may only happen every couple hundred years in northern Europe, but if one happens and you haven't designed around dealing with it, millions die here.
If the land is filled at or a bit above sea level, a 10+ meter tsunami would still cause largish devastation along the immediate coast facing the tsunami's wash, but wouldn't flood the entire zone and kill millions. And your original sea-wall may be left in place and built up a bit bigger to handle tsunamis and large storm-surges.
https://en.wikipedia.org/wiki/List_of_tsunamis_in_Europe
I like this idea. I think it gets cheaper if you consider that lots of parts of the UK (and possibly other bits of Europe) would be interested in losing very large volumes of land in order to create new lake districts, preferably of the freshwater variety.
Also, have you considered building the city round canals, like Venice?
“UK wages compared to 1998 Korean ones, which are ~86% higher than UK wages.” Think you meant that UK wages today are 86% higher than 1998 Korean wages.
Thanks, have changed
Wouldn't it make more sense to reclaim land next to the current coastline?
That’s where all the marine life is.
Where are you getting 2 Gigatons of rock from?
According to my calculations you need about 1000 Gigatons to fill that volume
https://www.wolframalpha.com/input?i=20%2C600km%5E2+*+25m+*1.2+*+1800+kg%2Fm%5E3++in+gigatons
Apologies, we did make an order of magnitude error with the calculations here - we would probably need to avoid this step and just place the volume of rock we discussed at the edges to prevent backflow, or perhaps cover the entire area with a waterproof coating. This shouldn't affect the rest of the calculations though - provided we can prevent backflow Dogger Bank should remain fully habitable.