For those of you who don't know, the Seto Inland Sea is a small body of water that is almost entirely within Japan's being. It is fielded on all sides by three of Japan's four main islands, Kyushu to the West, Shikoku to the south and Honshu to the North and North-East. It's decently sized but relatively shallow, with an area roughly 23,000km2 and an average depth of 38m. Seto Inland Sea is only accessible by five Straits.

With five dams with a total length of approximately 30km, you could completely seal Seto Inland Sea from the outside world. You could then drain it and create a huge fertile plain that will effectively combine Kyushu, Shikoku and Honshu into one huge island. Canals could be built to re-establish important waterways (such as the one from Kanmon Strait to Hoyo Strait). Think of the kind of economic boom that could bring. Even a boom population wise could happen if the project is completed at the right time in Japan's demographic history. Besides, how cool would it be for Japan to drain an entire fucking sea? That's the kind of thing that brings you prestige admiration in the international community.

I'm curious what others think. You cannot convince me this is a bad idea though.
 

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Can those dams withstand severe earthquakes? What about tsunamis? I don't think Japan is a good place to be living below sea level. Just because something is possible doesn't mean it's practicable.
 
You know salted earth doesn't grow anything right?

I wonder how the Dutch have worked around that?

Can those dams withstand severe earthquakes? What about tsunamis? I don't think Japan is a good place to be living below sea level. Just because something is possible doesn't mean it's practicable.

The Dutch system is vulnerable to storm damage. Look up the failures there back in the 1950s when North Sea storms overwhelmed the barrier system. The deaths and economic damage were big news when I was a child. The narrow straits can channelize storm surges & tsunami bringing enormous pressure on the barriers.
 
You know salted earth doesn't grow anything right?

Seeing that Japan are not a desert, rain would wash the salt out in relative few years. In fact there's large areas of Northern Europe which are former sea floor or salt marches, which have fresh water ground water today.

As for the fertility, as the sea floor lack soil, the new land will be sandy and lacking in calcium, this limits the crops which can be grown here. The area are most likely to end up cattle land, with some root crops like carrots and potatoes being grown on the new plains.
 

Deleted member 94680

Seeing that Japan are not a desert, rain would wash the salt out in relative few years. In fact there's large areas of Northern Europe which are former sea floor or salt marches, which have fresh water ground water today.

As for the fertility, as the sea floor lack soil, the new land will be sandy and lacking in calcium, this limits the crops which can be grown here. The area are most likely to end up cattle land, with some root crops like carrots and potatoes being grown on the new plains.

Or, you know, rice.
 

Deleted member 94680

I don't know what kind of soil rice need to grow, I just know that traditional European cereals would do badly in this kind of soil. Do rice grow well in sandy and acidic soil?

To be fair, I'm nowhere near being an expert myself. I only got it from the wiki page on land reclamation which says:
"In South China, farmers reclaimed paddy fields by enclosing an area with a stone wall on the sea shore near a river mouth or river delta. The species of rice that grow on these grounds are more salt tolerant. Another use of such enclosed land is the creation of fish ponds."
 
To be fair, I'm nowhere near being an expert myself. I only got it from the wiki page on land reclamation which says:
"In South China, farmers reclaimed paddy fields by enclosing an area with a stone wall on the sea shore near a river mouth or river delta. The species of rice that grow on these grounds are more salt tolerant. Another use of such enclosed land is the creation of fish ponds."

If we look at Europe rice have mostly been grown along the Rhone and Po. These areas are well known for their high quality soil. If we make the comparison with your quite from the Wikipedia article, I can guess the point about placing it at a river delta, are that the river bring nutricients from upriver. This lead me to think that rice growing will be relative limited on these new plains. Instead agriculture will likely be more like agriculture in Flevoland.
 

Vuru

Banned
You can make it a fertile land, but (and a big but it is):

1. you have to desalinate the soil (apparently this process is sorta tricky)
2. You have to make a lot of canals and levees for the rivers too so they don't turn it into a lake
3. the levees on the sea may have to be really deep, and wide to withstand being on the geologically worst location to ever be located
 
It's doable, but there's the issue of earthquakes. You'd need one hell of a dyke to prevent damage from a major earthquake. And even once you do it and drain it you just wind up with a huge salt flat. Granted you can scrape most of that off and dump it back in the ocean but you don't really have anything to replace it with. It's going to be pure sand and silt. Life will take there, but it would be a hideously expensive proposition with huge risks involved for very little gain imho.

Plus the environmental concerns from destroying an ecosystem wouldn't be negligible too.
 

Deleted member 94680

When is the POD for this meant to be?

Victorious Axis Japan?

OTL Japan Post-War?

Japan that doesn't get involved in WWII and tries other methods to overcome its resource shortages?
 
When is the POD for this meant to be?

Victorious Axis Japan?

OTL Japan Post-War?

Japan that doesn't get involved in WWII and tries other methods to overcome its resource shortages?

This sounds like it would be a product of the same mindset which came up with the Shimizu Mega-City Pyramid and such. Japan's economy only goes up, up, and up, its population never stops growing, etc.

So instead of putting 1 million people in a 2 kilometer tall pyramid in Tokyo Bay, you go for the more low-tech, less futuristic route of putting 1 million people in the now dry Seto Inland Sea. Except you're going to need to put way more people than that there, because all the port cities on the Seto Inland Sea will be taking a huge economic hit as the sea dries up. New cities will be constructed, of course. But you've gotta builld them from scratch, unlike all the cities which already have port infrastructure and infrastructure in general.

What is the soil liquefaction risk for building on former ocean? It can't be good. So in addition to the tsunami risk, which is by far worse than anywhere else in Japan, the earthquake hazard (property and lives) is now also the worst in Japan.

More farmland is always nice, especially in a nation with such little good farmland, but there's no way you're getting high-quality farmland out of this, no matter how you do things. Also, how might this affect the climate of Japan, since draining a body of water like this will have to have some negative effects.

Finally, how often has this idea been proposed? I think between this idea and the Pyramid, most sane people would choose the Pyramid. Especially if you happen to be a resident of one of the cities which will be most affected.

With how crazy this idea is, maybe this:In some Axis Victory scenario, the Japanese economy still takes off at the head of the Greater East Asia Co-Prosperity Sphere. Nazi engineers want to go ahead with Atlantropa, so they pitch the idea to the Japanese, supplying materials and scientists for assistance. The Japanese government feels fit to punish the people of the regions around the Inland Sea for...some reason, so nothing better to do than temporarily sacrifice their prosperity for the glory of the rest of the Empire of Japan. And so the project goes ahead, regardless of the issues.

Then in 1995, the Great Hanshin earthquake strikes...
 

Deleted member 94680

Finally, how often has this idea been proposed? I think between this idea and the Pyramid, most sane people would choose the Pyramid. Especially if you happen to be a resident of one of the cities which will be most affected.

With how crazy this idea is, maybe this:In some Axis Victory scenario, the Japanese economy still takes off at the head of the Greater East Asia Co-Prosperity Sphere. Nazi engineers want to go ahead with Atlantropa, so they pitch the idea to the Japanese, supplying materials and scientists for assistance. The Japanese government feels fit to punish the people of the regions around the Inland Sea for...some reason, so nothing better to do than temporarily sacrifice their prosperity for the glory of the rest of the Empire of Japan. And so the project goes ahead, regardless of the issues.

Or, victorious Imperial Japan is in a cultural Cold War with Nazi Germany. Once the Germans announce they're going to dam up the Mediterranean the Japanese have to launch a project back. Doesn't matter how dodgy the land is, they need to reclaim land from the sea...
 
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