I never heard of these possibilities - and why not? This is the kind of thinking we need. Of course there will be repercussions, but it seems they are manageable with the technology today. The world is so set in how things are done that opportunities like this are overlooked.
Great piece again, thank you! Could you add a column to the table listing all depressions: By how many mm would mean sea level go down if they were filled to MSL?
nearly all of these have been considered in decades past and the projects abandoned. by far the largest reason for abandoning the projects was the belief that over time the water would simply become too salty and then become a stagnant and dead swamp- people prefer a desert over a swamp.
The challenge here, Tomas, is to come up with the engineering proof to measure the amount of energy that would be needed to desalinate the water and the amount of energy needed to pump the salt-rich brine back to the sea, and figure out a scenario where the inflow to our inland sea is sufficient for both. Once you have that equation solved, the scenario becomes a very good hypothetical.
Qattara region can even be filled with the the flooding of the Nile which is happening on the yearly monsoon between May and August. And it would have fresh water, not from the sea. But it probably would affect to the needs of the Nile Delta, and it can have a side effect
Just remembered this article I read back during the (post-?)hurricane that hit California a month or so ago - You probably DON'T want to include the Salton Sea here.
(Actual paper is linked near the top, but the above link gives a good summary if you're pressed for time)
Major earthquakes on (specifically just slip-strike?) faults can be induced by large bodies of water forming over the fault lines, as it depresses the crust & lubricates the holding points enough to trigger a quake. You pointed out a lot of the potential spots for flooding are situated over faults, so that may be another issue to consider.
Still 100% agree we should be building these megaprojects - the benefits are huge - but some of these like Salton won't be worth the effort if they cause earthquakes in major population centres
(I should point out I have no background in this field & I'm going off of memory from reading it a month back, so I might be off on things)
using solar, and by my estimates and with the right technology, we can evaporate the sea using the sun and dump it into the depression. We will skip all of the math. Just understand that it was done using maximum solar possible efficiency and a totally passive system that will self-clean and self-recharge every day with the tides and the sun, and work year round.
we'll assume a 50% efficiency rate and that 640 acres will ultimately be needed per meter/second of water we wish to funnel into the depression. the depression's possible water holding capacity is approximately 1.213e+12 meters of water. my estimation is that around 100 miles of coastline are truly available and have not been significantly settled. I will assume that most of the desalinization facilities will be located on a single ridgeline of at most one acre deep which is artificially constructed near the beach, to minimize the amount of energy required, and that the fresh water will be pipelined into the depression from a buried collection system. Around 4 meters/second of water will flow.
The cost of the project, ultimately, is likely to be around 10 dollars per square foot, and totals 1,105,600,000- approximately 1.1 billion when all is done and said. This is around 1.25% of egypt's governmental budget, so it's not entirely unsustainable. However, labor costs and the cost of the land may be larger. So, in my estimation, the project is feasible, however.. that's not a lot of water.
Assuming there is no evaporation, it would require 11699 years to fill the depression.
I am all for megaprojects, but for seaflooding you really need to give consideration to the question of salt.
1. Water contains salt. Seaflooding leads to a net-positive salt flow into the plain.
2. Evaporation and constant flow cause salinity to rise. Long term equilibrium of seaflooding is a saturated salt solution with salt deposits forming on the bed of the lake. Not conductive to life.
3. High saline water level threaten freshwater aquifers in all surrounding areas.
4. If you want more than an evaporation pond for more rainfall, you must therefore desalinate.
5. Desalination costs energy. Seawater desalination energy cost currently stands at [1]
~3kWh/m^3, so ~3kWh/t=3600s*3kW=10 800kJ/t. From 100m of height difference, you only obtain 100m*10000N/t*1t=1000kJ/t. Therefore, you are essentially desalinating a lot of water to vaporize it in a lake. It is better to use it directly in irrigation systems.
Conclusion for me: The plan is only useful if you can accept a salt lake as the final result. Then you get a bit of electricity and more rainfall. So the plan would be very useful for wasteland without important aquifers.
Not sure if you have read about this idea for the Salton Sea, though it has more to do with stabilizing it's water level and salinity than flooding it (very fertile agricultural lands surround the Salton Sea so flooding any higher is not really a sensible option).
Tomas, any promising areas in Australia?! Itās prime real estate for renewables, so over time, generating electricity to desalinate and pump the water should be relatively cost effective.
I noticed that map mentioned Lake Eyre, but doesn't that already have water?
I never heard of these possibilities - and why not? This is the kind of thinking we need. Of course there will be repercussions, but it seems they are manageable with the technology today. The world is so set in how things are done that opportunities like this are overlooked.
Great piece again, thank you! Could you add a column to the table listing all depressions: By how many mm would mean sea level go down if they were filled to MSL?
nearly all of these have been considered in decades past and the projects abandoned. by far the largest reason for abandoning the projects was the belief that over time the water would simply become too salty and then become a stagnant and dead swamp- people prefer a desert over a swamp.
The challenge here, Tomas, is to come up with the engineering proof to measure the amount of energy that would be needed to desalinate the water and the amount of energy needed to pump the salt-rich brine back to the sea, and figure out a scenario where the inflow to our inland sea is sufficient for both. Once you have that equation solved, the scenario becomes a very good hypothetical.
why only look at below sealevel? with all the renewable energy and its peak productions, one could easily imagine other projects.
- aral sea
- mega lake chad
and so on.
Qattara region can even be filled with the the flooding of the Nile which is happening on the yearly monsoon between May and August. And it would have fresh water, not from the sea. But it probably would affect to the needs of the Nile Delta, and it can have a side effect
There was a big book decades ago on Macroengineering and the Earth. Bravura ideas, tough to carry out. I guess we'll see. My guess is the Dead Sea will be first. https://www.sciencedirect.com/book/9781898563594/macro-engineering-and-the-earth
Just remembered this article I read back during the (post-?)hurricane that hit California a month or so ago - You probably DON'T want to include the Salton Sea here.
Link: https://newscenter.sdsu.edu/sdsu_newscenter/news_story.aspx?sid=79250
(Actual paper is linked near the top, but the above link gives a good summary if you're pressed for time)
Major earthquakes on (specifically just slip-strike?) faults can be induced by large bodies of water forming over the fault lines, as it depresses the crust & lubricates the holding points enough to trigger a quake. You pointed out a lot of the potential spots for flooding are situated over faults, so that may be another issue to consider.
Still 100% agree we should be building these megaprojects - the benefits are huge - but some of these like Salton won't be worth the effort if they cause earthquakes in major population centres
(I should point out I have no background in this field & I'm going off of memory from reading it a month back, so I might be off on things)
using solar, and by my estimates and with the right technology, we can evaporate the sea using the sun and dump it into the depression. We will skip all of the math. Just understand that it was done using maximum solar possible efficiency and a totally passive system that will self-clean and self-recharge every day with the tides and the sun, and work year round.
we'll assume a 50% efficiency rate and that 640 acres will ultimately be needed per meter/second of water we wish to funnel into the depression. the depression's possible water holding capacity is approximately 1.213e+12 meters of water. my estimation is that around 100 miles of coastline are truly available and have not been significantly settled. I will assume that most of the desalinization facilities will be located on a single ridgeline of at most one acre deep which is artificially constructed near the beach, to minimize the amount of energy required, and that the fresh water will be pipelined into the depression from a buried collection system. Around 4 meters/second of water will flow.
The cost of the project, ultimately, is likely to be around 10 dollars per square foot, and totals 1,105,600,000- approximately 1.1 billion when all is done and said. This is around 1.25% of egypt's governmental budget, so it's not entirely unsustainable. However, labor costs and the cost of the land may be larger. So, in my estimation, the project is feasible, however.. that's not a lot of water.
Assuming there is no evaporation, it would require 11699 years to fill the depression.
I have always loved the word "picayune" and it's amusing that it's such a long word for referring to "tiny" or "insignificant."
Great article, food for thought. Seems like a feasible idea, if presented to the right audience. Thank you for this.
Interesting how California is dealing with this problem: "strategic retreat" is their euphemism for pack up and move to higher ground
Great
I am all for megaprojects, but for seaflooding you really need to give consideration to the question of salt.
1. Water contains salt. Seaflooding leads to a net-positive salt flow into the plain.
2. Evaporation and constant flow cause salinity to rise. Long term equilibrium of seaflooding is a saturated salt solution with salt deposits forming on the bed of the lake. Not conductive to life.
3. High saline water level threaten freshwater aquifers in all surrounding areas.
4. If you want more than an evaporation pond for more rainfall, you must therefore desalinate.
5. Desalination costs energy. Seawater desalination energy cost currently stands at [1]
~3kWh/m^3, so ~3kWh/t=3600s*3kW=10 800kJ/t. From 100m of height difference, you only obtain 100m*10000N/t*1t=1000kJ/t. Therefore, you are essentially desalinating a lot of water to vaporize it in a lake. It is better to use it directly in irrigation systems.
Conclusion for me: The plan is only useful if you can accept a salt lake as the final result. Then you get a bit of electricity and more rainfall. So the plan would be very useful for wasteland without important aquifers.
[1]https://en.wikipedia.org/wiki/Desalination
Great post... Iāve re-stacked with a note
Not sure if you have read about this idea for the Salton Sea, though it has more to do with stabilizing it's water level and salinity than flooding it (very fertile agricultural lands surround the Salton Sea so flooding any higher is not really a sensible option).
https://energycentral.com/c/pip/great-mexicali-energy-and-shipping-canal
Tomas, any promising areas in Australia?! Itās prime real estate for renewables, so over time, generating electricity to desalinate and pump the water should be relatively cost effective.
I noticed that map mentioned Lake Eyre, but doesn't that already have water?
My question is whether flooding the Qattara Depression would add salt to the Nubian Sanstone Aquifer System. How could this be tested?