How to Supply a City on top of a Vertical Cliff?

Question

In my fantasy series, there’s this city called Pharcos situated on top of nearly vertical 3,500ish foot high sandstone cliffs above the river it uses for water.

This river, called the Clazelis, along with the Thuridos that flows into it just south of the city, forms a sort of Mesopotamia-esque floodplain that makes agriculture possible in this otherwise desert landscape, and is deep enough to be navigable from Kerkapeze (a city even further upstream) all the way down to the coast.

However, the city of Pharcos was built on top of these riverside cliffs instead of below them directly along the river because the location on top of the cliffs gives Pharcos some access to the trade routes that go through the passes of the Monsaltu Mountains to the north, and the city was meant to be a sort of port where the goods carried overland on these trade routes could be put on ships and sent to buyers downstream, and because of this there are docks below the city along the river where this is supposed to happen.

My question is essentially how could a pre-industrial city in such a hard-to-reach location keep itself supplied with food and water and connect the docks along the river with the high-up city proper?

Answer 1

• Windmills and archimedian screws. The winds rush frequently past the cliffs, turning the archimedian screws that bring crescents of water ever upward. Each screw goes for only fifty feet or so, but the water pours out into a solid stone reservoir with a spectacular overlook of the cliff, from which the next screw takes up passengers.* The water flow brings along unmanned cargo pods as well, without the need for human intervention. After many such trips, the cargo eventually rides a river into the city. (*Passengers are rather discouraged, as the water quality can be rendered dubious if vessels remain trapped in the screws for days of calm weather, and captive riders may not practice good toilet etiquette)

• Stairs. Come on, people climb Everest with packs on their backs. That's what exploited lower classes were made for. (No, not slaves. You need people who will line up in the morning for turnips - and you only take as many as you need that day. When their knees give out, you send them away to blame the gods for their misfortune, not their city's illustrious merchants. Besides, flogged backs would stain the fancy bolts of cloth)

• Lifts. Like stairs, but you pull on ropes and pay careful attention to balancing your counterweights. The trip should probably be broken into several segments as with the screws. This can easily be done pre-industrially but there is more potential for entertaining mishaps. (These are manual, not water powered. The capital cost of another sequence of archimedian screws to bring up that water is a lot more than the capital cost of carving another shaftway or staircase and planting another acre of turnips)

• Pneumatic tube. After the bronze smiths broke the Bellows Union, the city snapped up the unemployed bellows operators. A steady stream of packages ride up the carefully-greased tube all the way to the city. Occasionally someone sends up a kid that way, though the tyke had better hope the package ahead of him doesn't get stuck because the guys downstairs aren't going to stop pumping!

• Hamster wheel. An entrepreneur noticed the daily crush on the stairs had reached homicidal extremes, with frequent casualties landing on the docks and damaging ships. With some investors in the Merchant's Guild, he had bold acrobatic workers carve a series of regular niches into the stone all the way up the side of the cliff, bridged by bamboo in places, in a perfectly straight line. A wheel of bamboo was then constructed, with bronze legs that lock into the niches. All the traveller has to do is keep climbing the wheel so that it moves ever upward by rotating into the niches. There is a special mechanism at the top to catch it and bring it in safely, and most of the time that works.

The remainder of the cliff is a rather chaotic mess of "runner-up" solutions: trampolines, hanging Tarzan vines, Rube Goldberg trebuchet arrays ... people have made it up that way, on occasion.

Answer 2

Actual port is 2 miles upstream

Behold the port of Savannah GA. It is the 4th busiest port in the US. The actual port facility is nearly 3 miles up the river. The city of Savannah is itself set back from the coast a little bit which is eminently practical in this part of the country. It is protected from storms and the coastal land is not good for building. The port is set back even further. Porto in Portugal is up on a cliff like your city and so also has its working port at a different site, but I like the Savannah method better if you can do it.

So too with your people. Boats coming to the port come upriver more than a mile before reaching the harbor. This harbor is buffered from ocean storms by the intervening mile. It is even better protected from attackers who would need to come upriver beneath the cliff which they do not like to do.

The land is at the level of the harbor up where it is. The city is then supplied via roads.

Answer 3

Realistically very difficult

Without an easy and cheap way to connect the sea-level and farm areas to the high up areas of the city, it is bound to fail. I do not have an accurate scale of what you are describing but I can not imagine many ways how people would solve this problem.
I think it is good to imagine how people would chose to start living in the area you are describing.

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Smaller villages are built next to the docks and farms.

This is done by the workers at those places and by businesses for logistical reasons. As these villages are concerned with resource production or supply, some of the people turn to marketing and caravans to sell the goods. The local market is small, just to satisfy the needs of the village but most devote a good part of their week transporting goods to the city where they cooperate with larger shopkeepers or operate stands at a big open market.

Caravans and transport services are expensive.

This is not an actual business for those who handle animals capable of dragging carts and caravans and offer to transport goods from the docks and farms to the city. Strong animals are valued for this. But, due to the high transport cost, the cost of the food/goods increases to make up for loses.
Does it make sense to live in the city and pay so much for the food?

How does the city solve the water problem?

This is something to consider for a city that is so high up and away from water. I imagine there must be some infrastructure or a number of individuals willing to make it to-and-from the river daily. I think this compliments the transport-heavy scenario. Keep in mind that water is consumed a lot faster that any food, especially in very hot areas.

Final thoughts

Location is very important when it comes to solving this problem. It is a lot more likely that the docks and farms would prosper and grow first, and as the city extends into the land, the high altitude of the cliffs could be used for scouting, lookouts or landmarks. Imagine something like Athens and the Acropolis.
I can also picture a select few that can afford the cost, to chose to have residents or important buildings away from the noise of the working or residential parts of the growing town.

Answer 4

Elevators

A wooden platform hangs from a sturdy pulley mounted at city level, with a heavy stone counterweight on the other end of the rope.

Because 1 kilometer is probably way too great a distance for the tensile strength of rope (and they won't have anything better), there will need to be many platforms built into the face of the cliff at intervals.

Wind will be a major hazard that not only threatens the lives of the staff at each platform, but also jeopardizes the freight or passengers being raised or lowered. So, the platforms will need to be shielded from the wind, as will the elevators; even so, you'll have occasions when something is too valuable to risk the elevators and must take the long road, and you'll probably also have people selling insurance that covers just the vertical transit.

If this situation persists long enough, I'd expect them to carve vertical tunnels into the rock to house the elevators.

Answer 5

Track-Climbing Elevators

Regular elevators generally operate by use of a very long cable and counter-weights.
Obviously a kilometer high cliff is far too high for any conventional rope, and steel cabling is perhaps outside the scope of your civilisation's technology.

However, a very clever artisan came up with a system of toothed tracks and gears which allow an elevator to climb any height as long as it has power.

A pair of oxen in a large hamster-wheel can provide that necessary power, which is translated through gears to the track and hauls the entire carriage up the cliff at a steady pace.

It may take a while, Oxen are not inclined to go quickly, and what with gearing the oxen are going to be travelling a lot further than the kilometre of the climb itself.

But you'll get there in a few hours, which is better than sailing downstream and walking a five or ten kilometres uphill.

Technical Challenges

"But wait! What's stopping the hamster wheel from spinning like a blender and killing the oxen?"
I hear you ask?

Worm Gears my friend.

A Worm-Gear is essentially a rod with a helix-shaped gear running down its length. Imagine a screw-thread without the pointy bit or the bit for the screwdriver on the other end.

With this, the motion is one-way. A cog cannot turn a worm-gear, but the worm-gear can turn the cog.

Consequently, with enough torque from the hamster-wheel and its oxen (and probably some clever gearing) You can travel up and down in complete safety.
The oxen can even get out of the hamster-wheel and be changed for fresh oxen at the end of each journey without the need for brakes!

The other concern of course is wear on the tracks themselves. Most likely you'd want to make them in sections as pieces of bronze or steel, but really if you make them chunky enough, wood will do fine.

You would want to have the mechanisms redundant and applying their forces across all four corners of your elevator too.

Ultimately, it'll have to be quite a large elevator. Think in terms of a structure comparable to a small building, with a hamster-wheel of oxen and gears in the lower half, and the cargo/passenger area on the upper level.

Of course, If it takes hours to get up and down you'll definitely want to have multiple elevators operating in parallel.

Most likely they run on a rigid schedule, perhaps with three or four elevators running, one might begin its journey each hour, every hour, and so workers in the port may live in the city above and commute each morning and evening.

Answer 6

Basic/easy answer: The cliffs are only steep on one side. The locals already called dibs on the easier side.

Maybe the mountains are further inland from the cliffs, and the river itself is a trade-route to the sea? I could easily see the river being (part of?) a gap/pass through the mountains, which is why the city doesn't need too much help with supplies: Because the locals wouldn't be CLIMBING the cliffs, just following the river upstream a mile or two, where the ground is much more level.

This means it's on the rainy side of the mountains as well, and the desert would naturally be on the other side; invaders would get bottle-necked if they want water AND a safe journey.

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Edit to add: OP mentioned that this city is inspired by St. Louis in Missouri, so here's my comment for "making the geography make sense."

St Louis is also by TWO major rivers (the Mississippi and the Missouri rivers meeting up) with at least one smaller river splitting off. With your rocky terrain full of mountains and cliffs, your Mississippi-sized river would inevitably split off into a few NORMAL-SIZED rivers. Perhaps your fantasy-St. Louis is technically in an oxbow of your fantasy-Mississippi, but the cliffs and mountains mean they're functionally located on "a huge river-island" instead of "inside the river-bend."

Edit 2: Here's St. Louis' geography from Wikipedia, showing the Mississippi River on top, the Missouri River in the middle, and two smaller rivers at the bottom. Even considering their much lower cliffs in real-life compared to OP's city of Pharcos, St. Louis' area was inhabited for a LONG time before Europeans, and their preindustrial inhabitants were clearly not suffering for lack of water or supplies.

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Edit 3: My answer would shift into:

-"Pharcos city's cliffs and mountains get really steep along X stretch of the main river. Sure, we've got plenty of those on Earth.

-The port-town is a few miles up/downriver. Also believable; it's not like sending boats or wagons an hour or two away is HARD.

-There's a lake or stream near Pharcos proper for water, irrigating crops, and local ferries with supplies. This seems almost inevitable for me, since this is such rocky terrain and especially if Pharcos is supposed to be preindustrial. Most people who know preindustrial logistics would "fill in the gaps" that there's the port-town, then there's Pharcos city a while off on the cliffs, and there are also nearby villages and farmlands for food-supplies.

I think OP is actually overthinking things a bit, because unless logistics for Pharcos are a recurring part of the story, people have built settlements in all sorts of highlands without a problem, and huge Mississippi-sized rivers are PRIME areas for building. Readers would see "Pharcos is on massive river-cliffs and there's a port X hours away. Yeah, they'd probably go overland or ship supplies over."

Answer 7

Many real cliffs have man made roads slanting upwards across their faces and sometimes zig zagging up the faces of the cliffs.

And sometimes those man made roads use natural features for much of their lengths.

And sometimes steep cliffs have natural features that make for easier climbs all the way to the top.

If the city is on top of cliffs at the junction of two rivers possibly a few streams or creeks enter the rivers near the city. And at least one of the creeks comes down from the cliff top near the city. It may have created a narrow canyon reaching down to the bottom of the cliff. A canyon with winding roads zig zaging from side to side and many bridges over the creek, and gated walls across the canyon to keep out invaders.

Or possibly there was a massive avalanche leaving a rockfall into the canyon of one of the rivers, forcing the river to divert around the rockfall. And maybe a winding road was built up the rockfall to the top of the cliff, or to a canyon of creek going the rest of the way up.

So possibly there is a much gentler slope up to the city on the cliff top, which helps traveling up to the city and down to the rivers, and which makes it easier to pump or carry water up to the city. But this slope is narrow enough to be well fortified against invaders. So presumably the city would only have to have a long wall on the side upstream to keep invaders from coming down the slopes to the city.

Answer 8

The town is above its harbor

The river is flowing right to the edge of the cliff, having cut it down akin to a canyon. But the people of the town have cut the harbor into the very foundations of the town, making space for whole ships right under the town and its subbasement. The result is, that the harbor is extremely protected from storms, super easily defensible, and has a lively community of tugboat rowers.

To get from the harbor to the town proper 3500 feet above takes a ride on the tunnel roads painstakingly cut through the rock, going up in serpentines. Straight parts are hugging the cliff faces with long, open-air windows, and with a moderate inclination of just about 5 feet per hundred feet, it's just about 70000 feet or 13.25 miles to get to the harbor. That's about three hours by foot. Considerable, but Rome's harbor Ostia was about 16 miles away, and Piraeus was about 6 miles from Athens, so we are right in between. As a result, there will be thousands employed in just ferrying the goods up and down the tunnel road.

Aquaeducts still the town's thirst

The town has built long and covered archway bridges that channel water from the Monsaltu Mountains to the north down to it and from higher land upriver, keeping it at a very shallow angle. With a width of a little more than two feet (70 cm) and having a depth of 5 feet (150 cm), that means when filled to the brim, we'll see about one ton of water per yard of aqueduct. That's very much the roman dimensions, and they managed such, so even with iron time tools, it is possible.

The aqueduct upriver might even be wider, possibly built in the shape of a long canal, and then used to ferry goods along it and irrigate the plains between it and the river. In that case, the construction will more look like the Los Angeles Aqueduct from Owens Valley in the Alabama Hills division: a 35 feet wide trench with 45° angles in an earthen embankment that offers 12 feet of depth at full capacity. Or, if we skip the need to ferry on that aqueduct, a 12 feet wide and 10 feet deep channel with a cover, like in the Mojawe division.

Answer 9

Assuming that the higher level has access to a lot of water - maybe there is a mountain range and a river that follows nearby over a water fall... With such an arrangement the water could be used to fill a large container on a trolley car with water at the top of the cliff. If that trolley car was connected to another trolley car via a rope over a pulley the weight of the first trolley car could pull the second trolley car up as it went down.

At the bottom the water in one trolley car would be released and the other trolley car would be filled allowing the process to reverse. With suitable control overt he amount of water cargo could be carried up or down.

With primitive technology it would probably require a series of such trolley cars as the ropes would not be up to a 1km stretch but with 5 or 6 it should be doable.

Answer 10

Assuming that deliveries must be sent vertically because there is no economical route along less-steep terrain, the most realistic answer is a series of lifts with stone counterweights. That's already been covered in @Tom's answer, so here's a significantly less plausible but perhaps more interesting answer:

There is a spring which is powerful enough to push water up to the top of the cliff where the city is, but a tunnel has been dug into the cliff face at the bottom so the water normally flows out of that tunnel instead. However, there is a heavy stone which can be moved with levers or pulleys to block the tunnel so that the water instead flows up through the shaft of the spring to the city at the top. Packages are placed at the bottom of the shaft, and then carried upwards by the water.

Everything arrives soaked, of course. That's fine for meat, fish, fruit and vegetables, non-ferrous metals, and anything that fits in a glass bottle. Heavy items must be tied to something that will float. You can send cloth, silk, rope, hardwood, and coal, if you leave it to dry after it arrives. Paper is difficult, but can be rolled up and sent in long thin bottles which are specially made for the purpose. If something must stay dry but won't fit through the neck of a bottle, then it must be wrapped and sealed with wax. It is not recommended to send non-aqueous livestock, pets, or people.

It's not very realistic, but it would be cool.

Answer 11

Pulleys. Lots and lots of pulleys. And some strong animal to pull the rope horizontally.

The basic setup is a block and tackle at the top, and a really really really long chain that attaches to the bottom block and your supplies. The setup could be broken up into a few separate ledges to make the chains less prone to breaking, although it would increase the cost and number of workers needed. A hook attached to the bottom allows you to pick up practically anything you'd want. To pull it, attach a bunch of slaves horses/oxen to the top end of the chain.

Answer 12

I had a similar setup in a fantasy city. A continental cataclysm had caused a massive cliff to split it across the middle at some unknown time in the past. The secondary trade river, tributary to the primary, ran to the cliff and fell off, over time eroding a canyon up to the main river. The canyon wasn't navigable, but the river was once you got above the waterfall.

The city was built on both sides and the dwarves had hacked the switchbacks into the cliff, with breathtaking bridges where they crossed back and forth across the canyon. Ships came up the main river, unloaded onto carts and wagons, and the wagons headed up the road. Once at the top, they unloaded onto a new set of ships bound upriver. Basically, the caravans just served as dedicated porters, constantly traveling up and down the cliff roads, and their support structure had moved into the galleries along the route, expanding them, setting up shops for food, drink, rest, etc. An entire suburb now exists along the route serving the caravans.

There were, of course, elevators provided for those who could really afford it, but the prices were exorbitant. Ballast was always stored at both top and bottom to serve as counterweights, so that the actual lifting effort was minimized, but it still took massive chains and ropes to lift even moderate cargo.

Answer 13

Water Columns

This is generally a one-way option for lighter freight, particularly for messages.

A water-filled tube has been created running the entire kilometer height of the cliff. Most likely drilled down from the top, through solid rock to port-level.

Via a modestly complex airlock, buoyant cargo pods with flotation devices can be transferred into the tube, where they will quickly rise to the top and can be retrieved easily.

This is largely unsuited for people, though a sufficiently large water-column might be able to carry a person in a cramped capsule.

It is however highly suited for sending important messages and small items quickly to the city.

Responses can be easily returned by being dropped down a similar tube with no water in it. It may be worth padding the bottom of the return-tube with straw or something similar to prevent the container being too damaged for repeated messages.

Answer 14

Rain, gold, and caves

This may be too simple, but there are places in the world that receive stupendous amounts of rain due to local microclimates. The West Coast of New Zealand gets 6700 mm of rain on average each year in the wettest places. A mere 300 km away, over some mountains, the climate is arid as almost all the water falls on the mountains. (Both regions are beautiful and a lot of fun to drive through).

The problem is that you've specified a desert climate around the city. So you need to either handwave a freak local wind that brings rain and dumps it only on the cliffs / mountain (not that silly), or have a very small, steep mountain range ringing the city on one side that does the same thing a bit more plausibly. If the mountains were virtually solid granite and also incredibly steep, rivers would form canyons and run away without making the area fertile.

Re: trade, if the upper cliffs are absolutely full of gold (or diamonds, or some other precious substance), even if all the port and agricultural work is done down below, people will ascend to trade for the gold up the top.

Finally: Maybe there's a limestone cave system that runs through the middle of the mountain in a really convenient spiralling way? It may have been widened into a smooth, convenient (albeit dark) path. It may also contain giant karsts that act as resevoirs at elevated levels.