Dealing w/ Extremely Populated Cities

[CityOfStreams]

So I'm building the world for a campaign I'm running. I'm taking a lot of inspiration from CityScape. To make a long complicated description short, my country is one giant city roughly 900 miles long and 700 miles wide. Giant outer walls and enormous districts separated by slightly enormous walls. There is a ridiculously huge river running next to the city and a giant canal has been diverted from the river and straight through the center of the city width wise. There are 3 inner walls that get progressively less far away from the previous wall as you get towards the center. The main canal has been diverted many times to bring water to all parts of the city. The most outer ring is the largest and the poorest. There are so many people living along the diverted canals (which are diverted into smaller and smaller canals to create an extensive network of waterways) for about 50 miles out to either side of the canals. The further you go along the canals the poorer it gets due to the increasing pollution in the water. The inner, more wealthy districts have fresher water due to access to the main canal but it's a similar theme as you go further along the canals. The inner most rings are ungodly wealthy compared to the outer ring and have access to very clean water as it is illegal to dump waste into the main canal. So even though the main canal flows through the outer rings to reach the inner rings. The waste is diverted around the inner districts and towards the poorest parts of the nation.

Okay now I realize that I just made a long explanation pretty long but trust me I could go into much more extreme detail.

Also I realized that you people are annoyingly smart and thorough ;) so one last thing. There are technically two outer rings but between the two most outer walls is just a giant ring of farmlands and an enormous rock quarry/Mining operation at one end.

Now, on to my question and the reason for this thread. This is my first very serious very planned out campaign. I am planning out so many details it's scary. But I can't decide how I want to handle shops and such in the poor district when there are so many people and so many stores. I don't want to give my players too many options right away as far as items go so my plan as of now is to limit the poor district to extremely limited items and a pretty low gp limit (more like sp limit & possibly cp limit in the worst areas), but I want to see if anyone on here has any good suggestions for laying out shops in the poor district.

Tl:dr colossal metropolis, high population, need help planning shops in poor district where populations are enormous.

Edit: I see that I have underestimated your thoroughness. Let me explain how this city came to be.

700 years ago in the year 100 b.w. (before walls) there were many nations and many cities. The world was experiencing an extreme magic renaissance, and the world was prosperous. It was not uncommon for the average commoner to be equal to a level 2 or 3 castor. Epic level wizards, sorcerers, clerics, and druids were still fairly frequent in large cities, but they were not the things of legend, because magic was in everything. Unfortunately centuries of excessive magic use had warped and changed the nature of this world. Almost like a pot boiling over, the magic aura that had been soaked in the earth burst forth into world and quickly began to change the natural world. Massive earthquakes brought into existence enormous mountain ranges, giant eternal storms brought torrential downpours that gathered into giant river flowing out of the ranges. Forest grew enormous and wild, but what changed the way of life for the people of the world was the effect that the magic had on the beasts in the lands.

Dire animals quickly became more common than normal animals, and magic beasts that the people had never scene evolved and crawled into existence. The trees, already grown to enormous sizes, began to take on sentience of their own. The dead came back readily, and soon there were undead far worse than any zombie or ghoul. Everything was bigger than it should have been, and anything that shouldn't have been at all soon become all too common. Then the magic began tearing rifts through the dimensions bringing in powerful outsiders in great numbers just looking for new lands to explore and conquer. Even for such a powerful civilization of humanoids, this world soon began to prove to be to great a challenge to survive in.

Desperate to avoid extinction, the remaining nations came together and formed a plan to survive. Gathering the greatest castors and adventurers in the land they set out to build a safe haven. For close to 100 years the humanoids fought off the onslaught from the world to protect the castors who set off to construct a walled off nation. Many died of unnatural causes during the building of these walls, either from the monsters attacking them, or from the excessive amounts of magic that were hastily being expended to raise these walls that were of such epic proportions. Any not powerful enough to aid in the construction of the outer walls began to establish the new nation in the interior. The location of the city-nation was selected to be near one of the great rivers that had been formed from the storms, because the massive amounts of freshwater that flowed through the river were necessary to support a nation of this size. This meant that the people had to start from scratch as none of the existing cities were anywhere near the great river. This haste to build a new city as quickly as possible resulted in the need for supplies, which led to the inevitable gap that formed between the relatively poor families who had nothing to offer other than their labor, and the terribly rich who had massive stores of resources at their back and the gold and platinum to set up the nation as they deemed fit. During the century before the walls were completed, the common people who in the past were able to practice magic at their leisure now needed to force their attentions elsewhere in order to survive.

By the time the walls were completed, roughly 10% of the original number of castors who spent much of their lives defending and aiding in its construction still remained. A council was formed and a decision was made that one final piece of protection would be necessary to ensure the peace of the nation. Almost all of the remaining castors joined together their combined powers and expended the last remaining magic they had, sacrificing their lives, to magically seal the nation off in an almost cylinder-like area. The protection strengthened the walls against physical damage, but its most important function was to block the magical pollution from entering that region of the world.

Within a century of the walls being completed, the people of this world were now about as magical as any normal Dungeons and Dragons world. Only those that had the ability, money, and will to practice magic could, while the rest of the nation had to focus their attentions on surviving among the masses of this nation sized metropolis. Fast-forwarding another 600 years and inner walls, extensive canals, labyrinth like sewer systems, rat's nest-like slums, extreme division of wealth and power, enormous farmlands, and most importantly, an almost completely unknown world outside of it all, make up the only known nation left in the world.

So now with that little bit of editing, go ahead.

[Yukitsu]

It's fairly simple really. Shop keepers in those areas simply optimize their inventory for what they can manage. If no one can afford expensive items, why would they stock them?

I'd be in favour of broad, crowded, smelly open air markets in poor zones with thousands of essentially free stands hawking wares to passing people. The items there would mostly be food or other necessities, and all of it would be what the people there could afford. Market space for things which won't get bought and which are of course, at risk of being stolen because of their value would not be stocked by these merchants, or would at least be well hidden.

If you want a mechanical justification as to the inventory, simply make sections of the city into their own cities on the demographics tables.

[Bronk]

I agree... the poor shops would have barely anything for sale, just cheap food, cheap items, and so on. Heck, there could even be food shortages for the main staples sometimes. Better stores could be in more affluent neighborhoods, and the best stores could be the kind you have to find and convince the proprietors you're worthy of being their clientele.

Or, you could go the other route, where local stores are offshoots of the more affluent stores, and the expensive items you might see displayed for sale are merely illusions of items you can order.

There might also be a large black market too, figuratively or literally, like Skullport underneath Waterdeep.

[Yukitsu]

They don't have to be poorly stocked. They could even be run by extremely wealthy merchants, but they know that no one is going to buy a +1 sword, since no one can afford it so they only stock things like socks. A merchant's guild could run a huge market in the poor districts that make them a lot of money overall because they're unregulated and sell cheap stuff. These could run with huge amounts of inventory, but only of things that earn them money there, that being cheap stuff.

[jiriku]

Take a look in your DMG at Table 5-2: Random Town Generation, on page 137. See how it has a gp limit based on population? Now, poor parts of town do not have interconnected economies. From borough to borough, perhaps even from block to block, you have individual town units that function like thorps, hamlets, and villages. People carry goods on their backs through roads that are little more than mud-choked tracks. At best, an enterprising commoner here and there might own a wheelbarrow. There's barely any trade in coin, because most of the commoners here don't own any coins and have to trade in kind or make their own goods by hand. No one from the richer parts of town bothers to set up shop here, because the people who live here can't afford to buy any goods worth selling.

As you get in towards the richest parts of town, the economy becomes more established. Broad districts function like towns and cities, with dirt roads that are maintained by local neighborhood associations, horse-drawn carts to move goods from place to place, and a vibrant economy trading in silver and gold. These economic units don't get too large, of course, because guild politics, tariffs and import taxes on goods from other neighborhoods, and turfs wars by petty officials prevent it. Serfs and petty servants may walk from the outlying districts to work here, then walk home to shop in their home neighborhoods -- there's nothing here they can afford to buy.

In the central city, business is booming, and in the sprawling, massive central district, business is the trade of the powerful. Flying carpets zoom overhead as barges ply the waterway and earth elementals haul great loads along immaculately maintained cobblestone streets. Merchants trade in platinum, gemstones, and even more exotic currencies, and strong central authority maintains the economic order necessary for the central city to function like a metropolis. Again, though, the factors and seneschals who serve the powerful may ride by horseback or carriage to the outer districts where they live and shop, as their salary of mere gold and silver coins will not buy the rare goods commonly on offer here. Likewise, there is a seedy, shadowy underbelly to the central city, where poor house servants and the destitute live in shacks or on the street, and operate a black market or trade with one another in back alleys and over kitchen tables -- the opulent markets of this region are far beyond their means, and they lack even the resources to own a horse or other conveyance to commute back and forth between their workplace and a cheaper district where they could afford to live.

[Ashtagon]

With regard to food transport, if the food can't get to market within two days of on a wagon, it's not getting to market without magic. In practical terms, the agricultural zone around any particular non-magical city is about 50 miles. I'm assuming your city uses magic to get food to the more central regions.

wrt to city size for purpose of magic items and those purchasing limit by city size tables, rather than treat it as a single city of a few umptillion people, do what Hari Seldon did when he explored Trantor. It's not a single city. It's multiple cities (each about a day's journey across) that simply happen to touch each other. Figure a day's journey as four hours out, a couple of hours shopping, and four hours back, on the form of transport most people will be using (ie foot), in crowded streets. Each "city" for this purpose is probably no more than a dozen miles across.

And yes, that means that even in "poor" districts, you'll probably have at least one magic shop selling powerful stuff, if you play by the tables. But that shop will be hard to find. Most shops will cater to the average local resident. Consider London. It's big enough that you can find a specialist shop that sells "spy" equipment, and another that sells umbrellas and walking sticks with hidden swords. But most shops don't sell these, and pre-Internet, good luck finding them.

[Yukitsu]

Depending on how they're constructed, food is much more likely floated down on the canals.

[Ashtagon]

Depending on how they're constructed, food is much more likely floated down on the canals.

Once you figure in loading/unloading times, that they can't travel at night so quickly, and that they do 10 mph on a good day, distances for perishable goods would be about the same. Canals revolutionised things because they enabled bulk transport, not because they were fast.

[jiriku]

I was also scratching my head over food logistics. A conservative estimate of that ring of farmland still puts some points on the inside of the city-nation as much as 200 miles from their food supply, and feeding an urban population zone the size of Alaska with a mere "ring" of farmland implies that they've found some way to break the usual medieval economy that expects 95-98% of the population to be subsistence farmers. At the same time, the fact that he does have farmland, that it's placed to minimize distances for overland travel, and that most of the city is poor seems to imply that the city isn't magically manufacturing its food and hasn't moved into a post-scarcity economy.

[Yukitsu]

^^^^
The most likely reason they can manage this is they are an Empire centered on a single city which receives a tithe from other nations which can't match them in military. A historic example of this sort of thing would be Athens. They conquered most of their neighbors but never officially annexed them instead demanding taxes or payments or unfair trade. Athens remained a city state but received goods, food and money from across dozens of other Greek city states.


Once you figure in loading/unloading times, that they can't travel at night so quickly, and that they do 10 mph on a good day, distances for perishable goods would be about the same. Canals revolutionised things because they enabled bulk transport, not because they were fast.

I'd disagree, the artificial canal systems in China revolutionized food distribution over much longer distances and much of the food eaten in Rome was shipped via boat from Egypt.

A lot of food that people eat in massive urban centers can last a good long while, but in older cities, things that had to be fresh could be acquired in the city. Small plots with vegetables or a few chickens in a house weren't unlikely. So long as grain could be shipped inward it wouldn't starve, and many vegetables in the day would last a while if cured, or some were just tough regardless like turnips. Cities like Rome or Beijing received most of their food from hundreds of miles away shipped by boat. A shipment which had turnips, bamboo shoots, dried mushrooms or artichokes as examples from real life "mega" cities all lasted a good long while and kept citizens of those massive places far from the farms fed. One of the most common trade goods in Rome were massive urns of olives which were traded by the ton so much that there's an artificial mountain made of used urns for storing olives and bringing them into the city.

Of course none of the pre-modern cities with over a million inhabitants ever were as large as this city would be, but they did find ways around food distribution to some extent. At any rate, their food lasted longer than 2 days from farm to table.

[Sith_Happens]

I was also scratching my head over food logistics. A conservative estimate of that ring of farmland still puts some points on the inside of the city-nation as much as 200 miles from their food supply, and feeding an urban population zone the size of Alaska with a mere "ring" of farmland implies that they've found some way to break the usual medieval economy that expects 95-98% of the population to be subsistence farmers. At the same time, the fact that he does have farmland, that it's placed to minimize distances for overland travel, and that most of the city is poor seems to imply that the city isn't magically manufacturing its food and hasn't moved into a post-scarcity economy.

It's not just getting the food to market that's a problem here, it's also getting water to the farms. The amount of canal-branching required to properly serve a contiguous ring of farmland with a six-digit area in square miles, at an output capable of feeding what assume is a nine-digit number of people, is going to come out to something similarly absurd. Then you have to make sure that none of those canals have the same "the water gets crappier the further you get from the main canal" problem that the populated area apparently has, else the aforementioned output requirements aren't going to be met.

It would make a lot more sense given both of those concerns for the country's farms to criss-cross the country, following the canals wherever they happen to go.

[jiriku]

Well, that's true, Yukitsu. But we're also postulating that the people in this city can't get their act together well enough for the entire megalopolis to function as an economic unit. So we've got a canal system providing water, a food transport system that consistently transports food up to a hundred miles per day, and no one in the outlying areas can sell you a spyglass or a suit of masterwork armor? I realize that this is one of those concerns that makes us "annoyingly smart and thorough", but I'd expect a government that's capable of feeding a population of millions by barge would also be capable of drop-shipping goods on those same barges. In fact, barges should be thick as fleas on those canals, what with all the trade going on.

Perhaps that's the answer. Maybe the canal system can only handle so much traffic, and so to ensure that vital foodstuffs aren't delayed, the rulers levy a punitive tax on the transport of goods by barge, but allow food shipments to be shipped untaxed. I bet there's a thriving black market in secretly transporting non-food goods hidden under crates of onions, in order to ship using the canal system while avoiding the taxes.


It's not just getting the food to market that's a problem here, it's also getting water to the farms. The amount of canal-branching required to properly serve a contiguous ring of farmland with a six-digit area in square miles, at an output capable of feeding what assume is a nine-digit number of people, is going to come out to something similarly absurd. Then you have to make sure that none of those canals have the same "the water gets crappier the further you get from the main canal" problem that the populated area apparently has, else the aforementioned output requirements aren't going to be met.

It would make a lot more sense given both of those concerns for the country's farms to criss-cross the country, following the canals wherever they happen to go.

Ok, I could see that. In which case, the water quality is high near farmland, but low as you get away from the high-quality canals used for irrigation. Again, I'd expect you'll have people who want to break the rules by piping water from the farms to the poor neighborhoods, and that could set up some intracity conflicts where the rulers are strapped for manpower to patrol all those miles of canal and punish water thieves, the poor neighborhood sees "the man" holding them down by denying them clean water, and some neighborhoods are about ready to go to war with the thieving neighborhoods because the theft of the water is causing their food crops to wither and threatening famine.

[Yukitsu]

Well, that's true, Yukitsu. But we're also postulating that the people in this city can't get their act together well enough for the entire megalopolis to function as an economic unit. So we've got a canal system providing water, a food transport system that consistently transports food up to a hundred miles per day, and no one in the outlying areas can sell you a spyglass or a suit of masterwork armor? I realize that this is one of those concerns that makes us "annoyingly smart and thorough", but I'd expect a government that's capable of feeding a population of millions by barge would also be capable of drop-shipping goods on those same barges. In fact, barges should be thick as fleas on those canals, what with all the trade going on.

Perhaps that's the answer. Maybe the canal system can only handle so much traffic, and so to ensure that vital foodstuffs aren't delayed, the rulers levy a punitive tax on the transport of goods by barge, but allow food shipments to be shipped untaxed. I bet there's a thriving black market in secretly transporting non-food goods hidden under crates of onions, in order to ship using the canal system while avoiding the taxes.

I suspect to help with the logistical burden, they simply receive shipments constantly and consistently rather than sending out messages saying they need one thing or another. It'd be possible that when you say "we need to get a suit of masterwork armour" to this burrow it may simply take far too long. In other words, I'd imagine that any barge would go down a set path on the canal through the city to the river, move up the river, collect more food, then go down the canal again. Diverting too much to get to a smith on the route may be too invasive to consider. I'd bet if demand in a section of the city changed dramatically, it could take weeks to resolve a change in shipment. The traffic on top of that, and the fact that they wouldn't by default ever want something that expensive in that area means there likely would be a lot of work to get through at the very least to buy such an item.

So I think it's less that they can't sell you a looking glass or a suit of masterwork armour, I suspect that it simply wouldn't be profitable enough for them to actually do it.

[jiriku]

Ok, if we imagine a shipping cartel that ships regularly and at high volume to specific shipping sites, they'd need to be heavily bureaucratized to handle the feeding of millions. You'd have a lot of rules and regulations to prevent logjams on the canals and little opportunity for unscheduled stops. That kind of super-conglomerate wouldn't have the time or the interest to send one spyglass to nowhere-town.

Would that leave room for some sort of small fry operation? Suppose you had something like single ships, owned and operated by their captains. They operate on the fringe of the city, taking whatever shipping jobs they can find, both legal and black market. Some days they make enough profit to keep Serenity flying and keep fuel in her tanks make it worthwhile, other days they lose money. Adventurers could tap into this network to request particularly expensive items in the out-town, but they might have to pay a premium, wait a few days, and run the risk that their goods might arrive late or not at all (rustled by the law, stolen by a rival ship, or sold to a higher bidder if their shipper is unscrupulous). That could be pretty cool actually.

[Yukitsu]

Yeah, I think that'd actually be exactly how that sort of thing would have to work. I'm sure there are other ways such a city could run, but I feel that this would be the most likely result, and smuggling and black markets would indeed be potentially lucrative.

[Sian]

instead of making farms lay in a outlying ring, how about using the magic that is around to make a similariy sized underground city (with underground rivers supplying water), with the lower population rarely if ever getting up above the ground, and the argiculture is based around eatable fungus and mushrooms, with the richest parts of the population being able to afford enough space to build rooftop gardens with more OTL common resources such as grain.

[The Evil DM]

With regard to food transport, if the food can't get to market within two days of on a wagon, it's not getting to market without magic. In practical terms, the agricultural zone around any particular non-magical city is about 50 miles. I'm assuming your city uses magic to get food to the more central regions.

wrt to city size for purpose of magic items and those purchasing limit by city size tables, rather than treat it as a single city of a few umptillion people, do what Hari Seldon did when he explored Trantor. It's not a single city. It's multiple cities (each about a day's journey across) that simply happen to touch each other. Figure a day's journey as four hours out, a couple of hours shopping, and four hours back, on the form of transport most people will be using (ie foot), in crowded streets. Each "city" for this purpose is probably no more than a dozen miles across.

And yes, that means that even in "poor" districts, you'll probably have at least one magic shop selling powerful stuff, if you play by the tables. But that shop will be hard to find. Most shops will cater to the average local resident. Consider London. It's big enough that you can find a specialist shop that sells "spy" equipment, and another that sells umbrellas and walking sticks with hidden swords. But most shops don't sell these, and pre-Internet, good luck finding them.

This assumes no preservation.

Rather than magical transport it could simply be forms of very low level magical preservation to prevent spoilage. An earlier edition had a cantrip called preserve that prevented spoilage of up to 2lbs per caster level for 6 months.

There are also non-magical means of preservation, canning, drying, salting etc. Even brewing beer is a means to transform the carbohydrates of a grain into an alcoholic beverage with caloric content.

[The Evil DM]

- Snip -
Now, on to my question and the reason for this thread. This is my first very serious very planned out campaign. I am planning out so many details it's scary. But I can't decide how I want to handle shops and such in the poor district when there are so many people and so many stores. I don't want to give my players too many options right away as far as items go so my plan as of now is to limit the poor district to extremely limited items and a pretty low gp limit (more like sp limit & possibly cp limit in the worst areas), but I want to see if anyone on here has any good suggestions for laying out shops in the poor district.

Tl:dr colossal metropolis, high population, need help planning shops in poor district where populations are enormous.

One thing to consider when using districts and limiting player movement.

No movement between districts without the appropriate papers. Of course only the wealthy can afford the papers.

[Ashtagon]

This assumes no preservation.

Rather than magical transport it could simply be forms of very low level magical preservation to prevent spoilage. An earlier edition had a cantrip called preserve that prevented spoilage of up to 2lbs per caster level for 6 months.

My initial post did highlight that I was talking about non-magical techniques. If you want to say a wizard did it (http://tvtropes.org/pmwiki/pmwiki.php/Main/AWizardDidIt), we're cool.

[The Evil DM]

My initial post did highlight that I was talking about non-magical techniques. If you want to say a wizard did it (http://tvtropes.org/pmwiki/pmwiki.php/Main/AWizardDidIt), we're cool.

I do realize that, which is why I also noted non-magical means of preserving food. Koreans have a high quantity of fermented foods in their diet (kimchee amongst other foods) because they could seal the foods up in pots, bury them while they ferment and then dig the pots up in the winter. Methods of preserving foods have been around for a very long time.

I would point out that a city of this nature would not function without magic or necessary technology in a climate that is not favorable to year round food growth. The food logistics are difficult enough for the size, but add to it a need for winter stores and the problem becomes intractable.

If you go to this list of world largest cities through history as a reference

https://en.wikipedia.org/wiki/List_of_largest_cities_throughout_history

You can see that until the industrial revolution allowed for Tokyo, New York and London to grow that all the largest cities were in the fertile bands of the world right around the northern subtropics.

-edit-

I wanted to add:

Other than preservation possibly providing some room for growth space (as pointed out by Yukitsu), I do not disagree with your 50 mile assessment for foods prone to spoilage.

[Evolved Shrimp]

Of course none of the pre-modern cities with over a million inhabitants ever were as large as this city would be, but they did find ways around food distribution to some extent. At any rate, their food lasted longer than 2 days from farm to table.

Reading about pre-modern cities, it seems that they all topped out around 1 to 1.5 million people. Apparently, that is the limit of how many people can be supplied with food using non-technical (and non-magical) methods.

By contrast, your city has – if we assume a fairly low population density, as cities go – about 3.5 to 4 billion (with a b) inhabitants. Assuming the population density of contemporary London, it would be about 8.5 billion – more than the entire current population of Earth. In either case, the city has more inhabitants than Earth could feed with pre-modern methods.

It seems that you can either hand-wave the issue of food supply or need to assume the large-scale use of appropriate magic. (A food-creating magic table in every home, or some such.) Same for waste-disposal. And probably for water as well – assuming 10 liters per person per day (too low, because it doesn’t fully account for water needed for crafts), you’re looking at about 40 cubic kilometers of water per day, which is the equivalent of 200 Amazon rivers.

[Yukitsu]

Reading about pre-modern cities, it seems that they all topped out around 1 to 1.5 million people. Apparently, that is the limit of how many people can be supplied with food using non-technical (and non-magical) methods.

By contrast, your city has – if we assume a fairly low population density, as cities go – about 3.5 to 4 billion (with a b) inhabitants. Assuming the population density of contemporary London, it would be about 8.5 billion – more than the entire current population of Earth. In either case, the city has more inhabitants than Earth could feed with pre-modern methods.

It seems that you can either hand-wave the issue of food supply or need to assume the large-scale use of appropriate magic. (A food-creating magic table in every home, or some such.) Same for waste-disposal. And probably for water as well – assuming 10 liters per person per day (too low, because it doesn’t fully account for water needed for crafts), you’re looking at about 40 cubic kilometers of water per day, which is the equivalent of 200 Amazon rivers.

There were other issues that prevented more people moving into one of these cities. Food distribution may have been the hard limit to these cities but it seems unlikely that it was the case. For example, a more pressing question would be whether or not these people could realistically have jobs. If they can't earn a living, they're likely to begin diffusing out to smaller towns or cities or back into the countryside.

I think we should assume that this city is much less dense than contemporary London. If I had to do the layout to a city of that scope, I would have drawn it up dotted with small farms and orchards spread through the entire city taking up a tremendous amount of the internal space in the city. Orchards in particular I think since they typically don't require irrigation. Even without these, one would assume density would be low with small 1 story houses or shacks being the standard depending on the wealth of the inhabitants. A city of this size, about the size of a large state could also have massive reservoirs or even full blown lakes taking up huge amounts of internal space.

[ExLibrisMortis]

You have a lot of canals, a lot of farmland, and a lot of water consumption there - the Gezira scheme (https://en.wikipedia.org/wiki/Gezira_Scheme), one of the biggest irrigated areas in the world, is 8800 square km big, and still about 75 times smaller than your city. Schemes this big create a lot of political tension when the demand for water starts outpacing supply.

It's important to remember that water flows from high to low places (more precisely, high energy to low energy, but gravity is often the dominant force on these scales). You won't neccessarily get a poorer water quality far away from the main canal, you'll get a worse quality further downstream. Rich people will live uphill, on villas with nice views, getting water from upstream through aquaducts, whereas poor people will live in the valleys and downstream (maybe near sea?), where the garbage gathers.

[Evolved Shrimp]

For example, a more pressing question would be whether or not these people could realistically have jobs.

Not really. For one, more people create more jobs locally (no transport problem). More importantly, people do not need jobs. Case in point: Ancient Rome was structured along a clientele system. While many people had jobs, many others did not and were supplied by rich benefactors – of course in exchange for supporting these benefactors politically.


I think we should assume that this city is much less dense than contemporary London.

Why? In fact, medieval cities were even more densely populated. A study (http://dspace.mit.edu/handle/1721.1/11311) gives a density of about 29000 people per square mile, which would result in a population of over 16 billion for our sample city.

But even if you assumed a density one tenth that of London today, you’d still be talking about 850 million people in one city – which does not materially change any of the issues.

[Yukitsu]

Not really. For one, more people create more jobs locally (no transport problem). More importantly, people do not need jobs. Case in point: Ancient Rome was structured along a clientele system. While many people had jobs, many others did not and were supplied by rich benefactors – of course in exchange for supporting these benefactors politically.

Population increases increase demand up to a point, but as you also mention, there were unemployed people in Rome. Enough that there were riots through the city from time to time. The amount people were paid by rich benefactors contributed far less to the number of people who could not find work in Rome when compared to free or subsidized bread which Rome could provide plenty of. Cut out the bread and circuses, suddenly that employment problem is going to be hitting much harder.


Why? In fact, medieval cities were even more densely populated. A study (http://dspace.mit.edu/handle/1721.1/11311) gives a density of about 29000 people per square mile, which would result in a population of over 16 billion for our sample city.

But even if you assumed a density one tenth that of London today, you’d still be talking about 850 million people in one city – which does not materially change any of the issues.

The reason why should be pretty obvious. If it weren't less dense, there would be no room for any agriculture and second because a city of that size before you could bring in literally all the world's resources could not function. I think a city of that size would have large portions given away to orchards, lakes and reservoirs that would dramatically cut population density. Even rocky hills or ridges which can't be built over.

[Flickerdart]

If there's one thing rich people love, it's estates. The population density might be high on the outskirts where shanty is built on top of shanty, but in the middle-class districts, people might come home to a nice house and garden, maybe even an orchard. The wealthiest districts would each be occupied by a single rich family and their attendants - the family doctor, the family tailor, the family chef, the family wizard... And the whole thing would be surrounded by forests and whatnot. And the wealthier the people, the more they can use magic to do away with things like "no water."

[Evolved Shrimp]

I think a city of that size would have large portions given away to orchards, lakes and reservoirs that would dramatically cut population density.

Well, that’s called “country”, then.

Of course you can do that, but it doesn’t sound to me like what the OP was describing.

[Yukitsu]

Well, that’s called “country”, then.

Of course you can do that, but it doesn’t sound to me like what the OP was describing.

It is a country. Given the size of the place, it would be more peculiar if there were no natural lakes within the civil borders, unless you want them to drain them for some reason.

As for agriculture, integrated agriculture within a city isn't common in places like the states, but it does happen in some cities as they begin to overtake farm land. The farms aren't considered in those cases to be outside the city.

[CityOfStreams]

Depending on how they're constructed, food is much more likely floated down on the canals.

Yes the canals are extremely essential to the city. Barges are able to move large quantities of food due to the sheer size of the canals. They're are highly regulated so it is not like Venice where anyone with a dingy is allowed on the water. Authorized transportation vessels act as transportation for those that can afford the over-priced transport cost, especially if you are moving between the district walls. Other than that, the canals are not overcrowded so barges can transport food quickly and efficiently from any direction.

[CityOfStreams]

I was also scratching my head over food logistics. A conservative estimate of that ring of farmland still puts some points on the inside of the city-nation as much as 200 miles from their food supply, and feeding an urban population zone the size of Alaska with a mere "ring" of farmland implies that they've found some way to break the usual medieval economy that expects 95-98% of the population to be subsistence farmers. At the same time, the fact that he does have farmland, that it's placed to minimize distances for overland travel, and that most of the city is poor seems to imply that the city isn't magically manufacturing its food and hasn't moved into a post-scarcity economy.

The farms are managed by the hundreds of thousands of people who have committed crimes not warranting imprisonment, forced labor at the quarry, or execution. Most of these of course come from the anthill that is the lower district. The upper class districts have enough influence to both avoid being sent to the forced labor, and to encourage the guards to be more than willing to send away the insignificant rabble in the poor districts for the smallest of infractions.

[CityOfStreams]

It seems that you can either hand-wave the issue of food supply or need to assume the large-scale use of appropriate magic. (A food-creating magic table in every home, or some such.) Same for waste-disposal. And probably for water as well – assuming 10 liters per person per day (too low, because it doesn’t fully account for water needed for crafts), you’re looking at about 40 cubic kilometers of water per day, which is the equivalent of 200 Amazon rivers.

As to the amount of water. The width of the primary canal is roughly 5-10 miles across, as the river it is diverted from is over 100 miles across in some places, and quite deep. The average canal that is diverted off of the main canal is about the size of the Amazon, and the next size down is about the size of the Mississippi. Water is not an issue for that. And in regards to food, I think I'll rethink my map putting additional farmland rings between each in ring of districts. Of course the entire world has been pumped full of ancient magic which can be seen in how readily and quickly the crops grow. I wanted to make it 'realistic', but D&D realistic. Food shortages will of course be a common theme in the poorest district ring.

[Telok]

Water is food here. The Amazon alone supports a number of fisheries.

For transport downstream is easier and faster than upstream. A well planned canal system designed for food transport will have the perishable food production upstream of the population centers. Less perishable foods (cheese, grains, nuts, dried fruits, etc) can be produced downstream while livestock can be walked into the city and butchered into food there.

Versailles is a palace whose grounds include fields for flocks of sheep.

The food thing isn't impossible, it would require centralized planning and organization though.

[CityOfStreams]

A well planned canal system designed for food transport will have the perishable food production upstream of the population centers. Less perishable foods (cheese, grains, nuts, dried fruits, etc) can be produced downstream while livestock can be walked into the city and butchered into food there.

That is a very smart idea that I had not thought of. I agree with almost everything everyone is saying, but this is a very smart idea. Thank you.

[gomipile]

With regards to the culture and atmosphere of your city, you might want to check out the novel Perdido Street Station for ideas.