Subterranian City Planning

[madcowchef]

Seems like there is several questions that will effect a lot of the answers you can give as to how an underground city and/or region would be laid out on a map.

How far underground and how self sufficient?: Is the settlement either easily reached by straight large paths or only a small ways underground so that most of the resources such as food and air within easy reach, or are these subterranean cities deep underground with no, limited, or time and resource intensive access to the surface? There is of course a wide spectrum between those. The later seems to require more modifications to the real world than the former which is easily accomplished. A map of someplace built underground to take advantage of valuable but fairly easily reached resources or built into a hill for protection seems like it would look little different from the map THW posted or like an ancient mine complex. More vertical but otherwise with few features different than any city map.

How human like are the inhabitants and how earth like is the world?: Are we talking fantasy dwarves, scifi aliens, or something between the two? A fantasy race or scifi race that doesn't look almost completely human but was actually adapted to living underground (probably look a bit like everything that takes up this life style moles, mole cricket, fairy armadillo, etc.) then they won't be in fear of needing heat except for the use of it in the civilized pursuits of material science and getting the most nutrition out of food (or if they were from deeper still and found the colder temperatures further from the truly deep underground a bit chilly). Presumably they wouldn't need it for light either as few of the worlds subterranean inhabitants are big on it. More human like races will need far more of the things we do: heat, light, better ventilation. All this of course can be changed on less earth like world with different resources available be it from ecosystem, geology, or magic (hopefully the kind that creates as many problems as it solves because simple hand waving is boring). How common giant caves or tunnels leading between subterranean areas are will effect transportation and expansion a lot also. If these changes are included they will give you a very different layout depending on how abundant these resources are and how they fall in the world.

What material sciences are available?: Most fantasy races seem to spring into the world with fully developed material sciences that allow them to live where they do, and why not if the gods made them for it? Less divine races will need to develop their technology in a more reasonable way with the available resources underground if that's where they started or by taking above ground inventions and re-purposing them for their new life style. If you want dwarves that can breath using only ancient technology, the water wheel and the windmill are both ancient enough to reasonably appear in at fantastic setting, though it would be novel to use the sails of the windmill to push rather than catch the wind. Other worlds and other resources would spawn entirely different sets of answers as to how to accomplish the same thing.

Ok my head is filling with an obsessive desire to to fill in increasingly smaller details so I had better stop for now.

[Gamerprinter]

Food
Most of the time the food source isn't even considered, even in the case of your typical dwarves shunning everyone else and living deep underground. They often seem to eat a lot of meat - where does it come from? Do they have the equivalent of underground factory farms (since space would be at a premium)? Where do they get the feed from? Where do they get their own vegetables, since pseudohumans presumably need the same nutrients humans do in real life, which cannot be provided by meat alone. Do they farm fungi (and if so, what do the fungi consume)? If all food is brought in/traded from outside, then can it truly be considered an underground civilisation rather than an outpost of a larger civilisation?

I cannot claim that every underground city map has effectively shown it's source of food, but I can remember the boxed set to city of Menzobarrenzan, the Drow of the Underdark, where the map depicted an area about a fifth of the size of the entire city chamber as holding an underground lake, islets, fungus fields, even underground cattle raised there. Realistically there probably was need for a larger more extensive area to serve as farms to adequetely feed the city, but it did exist on the map. Often there is a nearby underground sea or lake that might serve as the primary source of food as in fish, and might be very close, but not an actual part of the underground city map in of itself.

Water
This the easiest to account for thanks to underground rivers, though it'd also be nice to also see references to rainwater filtered through the rocks. Water collectors built underneath stalactites would be a pretty cool detail. You could also cut wells down to the water table.

There are probably dry cave systems in the underdark as well, but if there is no water source, then there is no city. I would believe any underground city requires underground cities, great aquifers, underground lakes, even collected water dripping from the ceiling of caves. Most underground city maps feature a river or lake within the community borders.

Oxygen
Another one that doesn't seem to be considered, there really does need to be some reliable ventilation. This bit reminds me of ants and termites - they create brilliant ventilation systems to manage the oxygen and carbon dioxide levels so both they and their farmed fungi can survive indefinitely. You'd have to design your architecture so that the air can flow through properly, circulating the air and keeping it fresh. Some modern buildings do this passively, so they'd be a good place to start looking at to see how this could be done.

I've never seen air ducts accessing the surface for most underground cities, and though this might not seem realistic, for reasons of safety, only one or a few entrances are even wanted for access to an underground city for the sake of defense. Most underground cities aren't near the surface, so any air ducts would probably have to be very deep, and if they are straight verticle ducts their existence might prove to offer unnecessary access to the city. Also, one would have to believe that an actual underground race should be biologically adapted to working in an environment with lowered oxygen levels. If its a surface race that has moved underground, they will certainly need some type of air duct system. If its an underdark race, I have to assume they are adapted to live and operate in lower oxygen levels, or increased levels of carbon dioxide and other gases. Not all races might need an air filteration system to survive in the Underdark.

Living Space
As you said, this could be planned out in advance, particularly because weakening the structure of one area could bring the whole thing down. It'd make sense for the plan to be constructed in stages, with various sections being planned well in advance and then excavated when the extra capacity is needed. However it could still be grown as per normal cities - and then you'd be able to add a third dimension to the growth, allowing connected infrastructure to cluster together more closely. I think the routes goods travel would be influenced by that - carrying heavy stuff upstairs all the time would be a nightmare, so a well organised city would arrange things so that goods tended to travel downhill or stay on the same level.

Looking at Menzobarrenzan again, many of the drow house 'castles' were rock-cut chambers cut from existing giant stalagtites and stalagmites, also many were typical stone and mortar constructed buildings like any surface city. Anywhere that exists a verticle surface in the walls of an underground chamber are regions of mostly solid rock, thus rock cut chambers, tunnel systems (like those in Cappodocia) would probably be prevalent. Even a wide pit that drops some distance in the floor of a cave, could serve as a 'skyscraper' going down, with levels, chambers, tunnels, even bridges across the pit, connecting to the lairs that surround the pit in the walls of solid rock. It might even be possible to build wood-like surface structures from the 'timbers of giant fungus'.

And with large enough chambers, I don't see why an underground city might not actually resemble a surface city with roads, alleys, enclosed yards, market squares and rows of constructed buildings. There are literally enormous open chambers found in Mammoth Caves, Carlsbad Caverns and other actual underground cavern systems on Earth. There's no reason why a surface looking city could not exist underground.

Temperature
Another thing that's often ignored - beyond the influence of the sun it's cold, until you get reeeally far down. If you're using big fires to keep the temperature up, where does the fuel come from, and how do you deal with the smoke?

The obvious solution to all of those problems is magic, but I think that would be kinda lame...

The first thousand feet under the surface the ambient temperature is fairly constant at 50 - 55 degrees F, though this varies in depth. As long as there is some internal heat source in homes and structures, this temperature range is survivable for most surface/underground sentient races. However, even without nearby magma chambers, volcanic channels, steam vents or geyser aquifers, you don't really have to go to far down to find the temperatures rising. Deep mines even those from as far back as the medieval period were found to be warmer in the lowest levels. I've read National Geographic articles regarding the diamond mines in South Africa, and at the lowest levels of the mine, it is almost too hot for humans to work in (and its not even a mile deep). So though the earth's core might be hundreds of miles down, you don't even need to get close to that to find hot temperatures underground. Even if a city resides above the warm layers, it would be probably be more practical to dig air ducts down to the warm levels circulating into the inhabited chamber (than digging air ducts to the surface.)

Nobody builds a surface city where there are no resources to support it. So I wouldn't think an underground city would appear anywhere there is an open space underground, if the supporting resources aren't there, neither is any population. There needs to be the basic resources to support life at any location for a city to be founded.

[madcowchef]

You make some very good ones about existing caves and resources GP. Your points about open vertical spaces definitely inspires. I disagree with you on about adaptions being an easy explanation for highly active creatures living in oxygen poor environments. From a biological standpoint unless you are going to wave away the matter in the interest of fun and fantasy, which I am all for in many settings, things that live in low resource, oxygen poor settings should look like the kind of organisms that fill that role in the deep sea: sluggish and often opportunistic. Deep sea organisms might be an interesting starting point for the kind of creatures one would find inhabiting such an environment in general, but not usually population dense enough to make for good civilizations. The level of bio-luminescent natural arms race found in the deep sea would certainly give a fantasy world's underside a interesting feel.

Looking at older building styles and thinking of the vertical nature that the life style lends itself to I'm wondering if those horrible thin steps or a lot of ladders would be a common feature. For moving larger loads they certainly don't make sense but for your average personal transportation ladders seem a common solution, though perhaps if you are cutting out rock steps are more sensible?

[KenG]

Interesting thoughts and discussions. As for food for the dwarves I seem to remember there were stories of the dwarves raising flocks of sheep and goats that they kept in the high mountain passes.

Here is a link to the salt mines in Poland that have been used in many different fashions since being established in the 12th century.

Bochnia Salt Mine - Wikipedia, the free encyclopedia

[bartmoss]

What's your tech level or magic level? In a magical society, you can probably illuminate your caves any way you want (GM's/author's fiat).

In a reasonably high-tech society, you could use these: Light tube - Wikipedia, the free encyclopedia

[lostatsea]

Interesting thread. Even in the "Real World" life adapts . Some times in the strangest ways. Even without Modern technologies Humans Have survived in the most inhospitable places of the earth. Likewise most members here see lifestyles with prejudice to how we live now and (WHERE) we live now. Most of us live in modern cities with all the convenience that en-tales. But a large part of the world's population doesn't have tv ,heat on demand or easy water or sanitation.
A modern city is hardly self -contained. I have no Farms " IN" my town and most of my clothing comes from china and my favorite fruits from South America. I don't see how self sufficiency would even be a criteria.

Air supply might only require some good cross ventilation. (Preexisting or manufactured). Also Carbon or other minerals naturally existing could be used to "scrub" the air .In a fantasy setting whole ecosystems might be able to support small villages. Mega cities even today need lots of outside support. Native Americans in the southwest built cliff dwellings. Vertical is a good alternative to urban sprawl. Where available.
The more primitive the "Society" the more they made do with what they had. Adapt/ move or die out . Oft times to deadly consequences. Note the number of ruins in our own world. The more advanced a civilization the more they alter their surroundings to suit themselves.

My first contest entry was a underground cohabitation between humans and giant ants/termites.It was very spartan and beneath a desert .They could survive on what they had beneath or could forage. They supplemented that by trading skilled crafts for raw materials. Each nest's Population was determined by what it could support on the resources at hand. Bed time for me. 4.30 am comes to early so I can commute to work. Hell even my job isn't self contained in my city.

[Wingshaw]

If I can go completely off topic for a moment, I'll address something that lostatsea said:

The more primitive the "Society" the more they made do with what they had. Adapt/ move or die out . Oft times to deadly consequences. Note the number of ruins in our own world. The more advanced a civilization the more they alter their surroundings to suit themselves.

If you are implying that old civilisations 'failed' and are hence in ruins, I would suggest a bit of a twist on that idea. The city of Catal Huyuk in central Turkey is one of the oldest ruined cities anywhere in the world. It also lasted for nearly 2000 years, making it longer lasting than all modern countries, several major religions, and the majority of the world's cities. Just something to think about.

Now, returning to topic, I definitely agree that no city, modern, historic, or fantastic, can be utterly self-sufficient and introverted.

[lostatsea]

No I didn't mean to suggest that all ruins were unsuccessful but rather that often cities were abandoned when they were no longer viable for some reason .
Sometimes they exhausted their resources. sometimes they out grew their resources and moved. Sometimes they were forced out by enemies. Sometimes they left due to religious beliefs. Sometimes a natural disaster or sickness ! Side note today's huge populations wouldn't exist if farming technologies hadn't vastly improved the amount of food production per acre. Technologies allow survival in areas otherwise nonviable. Less advanced cultures either adapt to what is available or have to leave for greener pastures or pass out of existence. Sometimes it is a combination.

As an off side I love the appropriate add below . "looking for underground bunker? Find it nearby with local.com "

[madcowchef]

I think we all agree cities only exist where the resources to support them exist, and only continue to exist for as long as that's the case. You don't place your biggest city on a map where the requirements for a large city are abscent. Its about laying out what the necessary resources to support it are, so that you can find where they should be located for your map. As far as self sufficiency that's a sliding scale: on one end is the smallest city state, where a single city is supported only by the region immediately around it (which has implications when you are far underground); on the other is the underground equivalent of a massive trade city that couldn't possibly be supported by the region around it or which can easily make up for some lacking key local resources through trade underground Rome at its height. Cities are never self sufficient in the sense that in the city itself they are producing enough food to feed everyone, unless we are going for underground arcologies.

[Wingshaw]

No I didn't mean to suggest that all ruins were unsuccessful but rather that often cities were abandoned when they were no longer viable for some reason .

Fair enough.