Ancient Engineering Science So Advanced It Is Like Magic
April 24, 2016 2:50 PM   Subscribe

Scientists have solved an ancient Peruvian mystery from space By using corkscrewing funnels, the Nazca were able to use wind to move underground water supplies without benefit of electricity, thus allowing for “an inexhaustible water supply throughout the year" and "an intensive agriculture of the valleys in one of the most arid places in the world.”

It was previously believed that the funnels served as maintenance entrances for annual cleaning of the aqueducts and were likely capped in some manner to keep debris out (which now seems very unlikely). It has also been much debated whether they were an artifact of Nazca civilization, later Inca civilization or introduced more recently by the Spanish in the 16th century. It seems the two significant conclusions from the recent satellite research are 1) they have dated these structures to the Nazca time period, settling the long standing debate about their age and origin, and 2) the unusual looking funnels are not merely some weird, artsy entrance but, in fact, are carefully designed engineering features used to capture wind and thereby move water through the system. In essence, they are an advanced, elegant hydraulic system.

Interesting background here with good info about the geology and hydrology of the region.
Additional historical perspective.
Pics!
posted by Michele in California (47 comments total) 75 users marked this as a favorite
 
This is amazing, but I feel like I need an animation or something to visualize how this works, particularly with how the wind is "captured" and how that pushes the water to where it needs to go.
posted by Karaage at 3:06 PM on April 24, 2016 [10 favorites]


Nice reminder that Homo sapiens have been sapiens for far far longer than we smartphone-toting Johnny-come-latelies tend to remember ;)
posted by ccaajj aka chrispy at 3:16 PM on April 24, 2016 [28 favorites]


Maybe the air cooled (and sank) as the sun set and/or the water underground drew the air into the funnels, similar to a Windcatcher?
posted by falsedmitri at 3:16 PM on April 24, 2016


Maybe the air cooled as the sun set and was drawn into the funnels?

The atmosphere constantly presses on the earth due to gravity. So when the prevailing wind blows in to the start of the corkscrew it'll do two things. First it will follow the road down because of the air pressure on top of it and gravity.

The second thing it will do is, as with any vortex, create a low pressure area in the middle. The air on top will rush down into the low pressure area sucking even more air into the hole.
posted by Talez at 3:22 PM on April 24, 2016 [9 favorites]


This is utterly fascinating. The main link intrigues, but the first "interesting background" link is truly worth reading (at first it seems like a dry academic paper, but I read avidly all the way through). The "additional historical perspective" is also a great read, and I love the way that it highlights the difficulty and controversy about understanding the origin of these structures. Nice job putting this post together!
posted by brambleboy at 3:22 PM on April 24, 2016 [3 favorites]


The attendant PDFs seem to indicate that these were "filtration galleries" - gravity fed - and make no mention of air being used as motive power.
While gravity certainly qualifies as magic in my world, I would love it if somebody can describe how these might otherwise work.
posted by Alter Cocker at 3:24 PM on April 24, 2016


I have only had one class in hydrology and chose to not pursue civil engineering because it requires all kinds of calculus, but if you look at the pics that show multiple puquios next to each other, in some you can see that the beginning and ending of the corkscrew is at different places for each one. If you assume this to be random, you think "aw, dumb folks from an ancient civization" but if you assume they are an engineering feature, then this would be intentional and have a function. So, my semi-educated guess is that the corkscrew provided direction to the existing winds, and this helped push the water in the direction needed to move it on down the line in the right direction.

Some places have strong winds regularly and can be counted on. If you live there and spend a lot of time outside, you can readily have good familiarity with the direction they come from. You need a design that opens such that it allows wind in from that direction and the outlet needs to direct it where it is needed.
posted by Michele in California at 3:24 PM on April 24, 2016 [3 favorites]


To me these look like the Peruvian version of the step wells that are found around India.
posted by sneebler at 3:25 PM on April 24, 2016 [1 favorite]


similar to a Windcatcher?

A windcatcher just uses static pressure of the wind. Simply: what goes in must come out the other end. The windcatcher's ingeniousness is using higher air and diverting that air downwards to deposit dust because sending it through the residence. Also if you run air over a hole that has cool, moist air from a Qanat into it you'll naturally draw that cool moist air up into the residence.
posted by Talez at 3:26 PM on April 24, 2016 [1 favorite]


Those ancient astronauts sure were clever.
posted by Punkey at 3:26 PM on April 24, 2016 [18 favorites]


(I am a bad person for faving that and should feel bad.)
posted by Artw at 3:28 PM on April 24, 2016 [6 favorites]


Punkey, that's the kind of heretical thinking you get when you listen to a bunch of godless scientists.
Clearly they were built to store grain.
posted by Trinity-Gehenna at 3:32 PM on April 24, 2016 [3 favorites]


this work doesn't seem to have been published anywhere, yet. afaict it all comes from one press release. :(
posted by andrewcooke at 4:08 PM on April 24, 2016 [1 favorite]


Yup: Lasaponara is publishing her work later this year in a paper called Ancient Nasca World: New Insights from Science and Archaeology.

All the articles I could find basically rearrange the same quotes. So I added what I could to flesh it out.
posted by Michele in California at 4:13 PM on April 24, 2016 [5 favorites]


Yea, the engineer in me wants to see numbers.
posted by RolandOfEld at 4:41 PM on April 24, 2016


According to the article, "The spiral-shaped holes work by funneling wind into underground canals, wind which then forced water from deep subterranean reservoirs to the places it was needed. Any water left over was then stored in surface pools."

Unfortunately, this doesn't make sense because air pressure doesn't work like that. Blowing wind into a bunch of tunnels, no matter how cool the spirals appear from space, isn't going to accomplish anything.
posted by sneebler at 4:43 PM on April 24, 2016


I think what they discovered from space was the distance from these holes to historic population centers. My theory on what the theory is is that by seeing what settlements the holes are near, they can say that they were made around the same time as those settlements were populated?

I'm also confused about why some articles say the holes still work today. If so, shouldn't there be more understanding of how they work? Stick a drone down there!
posted by rebent at 4:49 PM on April 24, 2016


tl;dr : Gravity does 99% of the work, not wind.

After encountering them in Iraq, I have done a fair amount of research on a middle-eastern variant of this system, called the Qanat. Which makes me pretty certain from the descriptions that the prime mover for getting the water from the mountains to the plains is still gravity. The ventilation tunnels certainly assist this process, but it is mostly just a long underground canal gently sloping downward.

...I feel like I need an animation or something to visualize how this works, particularly with how the wind is "captured" and how that pushes the water to where it needs to go... Just think of it like a house on a windy day. You open the front door, not realizing that the side door was open, and you hear a bang as the side door slams shut. That is how the wind comes in through those sprial shafts and helps push the old air out at the discharge point miles away, only there is no door on that end to slam shut, obviously, so the air has a more or less steady flow through the underground tunnel.

To me these look like the Peruvian version of the step wells that are found around India. Most stepwells merely store water in an accessible way that accounts for variations in water table in a desert climate that has occasional monsoons. Whereas this puqio and middle-eastern qanats actually move water long distances from the mountains where it is relatively plentiful to the plains where it is needed by humans.

To further complicate matters, the Spanish saw numerous examples of this technology brought to the drier parts of Iberia by the Moors, and also traveled to North Africa and the Middle East and saw qanats there, which is why you sometimes see the technology used in places like Guadalajara, Mexico. So I wouldn't completely rule out that this isn't a Spanish installation, either.

No matter what, it is an interesting article, about a great low-tech solution thousands of years old that still has potential to help populations in arid regions today. Several 1000+ year-old qanats in Iran still bring water to their communities from many miles away.

But yeah, it's gravity that moves the water. The air shafts are essential to the process, but they don't do the work. Any other interpretation is just hype and marketing, I think. But perhaps a real expert will come along and prove me wrong?
posted by seasparrow at 4:56 PM on April 24, 2016 [29 favorites]


i know everyone thinks the ancient aliens shit is so hilarious and everything but it's some fundamentally racist bullshit based on erasing the accomplishments of nonwhite civilizations and i'd love to never ever see it again, thanks.
posted by poffin boffin at 5:03 PM on April 24, 2016 [26 favorites]


(Which now has me thinking how we, as a society, think of mythical space aliens as "super whities".)

"Underground canals" seems dangerously glossed over. That, in and of itself, seems like a huge engineering project, which must have left tailing piles and if some are still functional should still be able to be explored. "What's down these holes? Huh, water, and what looks like engineered tunnels for said water, I wonder what these could be?"
posted by maxwelton at 5:16 PM on April 24, 2016 [3 favorites]


As a symbol the shape is used all over the place. That spiral. I am not getting how wind pushes water after speeding down a spiral, unless it messes with air pressures somehow that lets water flow, rather than pushing it. Is there a spinning shaft, like a water pumping windmill has. Is that a part of this system?
posted by Oyéah at 5:16 PM on April 24, 2016


Punkey, that's the kind of heretical thinking you get when you listen to a bunch of godless scientists.
Clearly they were built to store grain.


I believe the default for things we don't understand is "of ritual or religious significance"
posted by Pope Guilty at 5:28 PM on April 24, 2016 [5 favorites]


"Underground canals" seems dangerously glossed over. That, in and of itself, seems like a huge engineering project, which must have left tailing piles and if some are still functional should still be able to be explored. "What's down these holes? Huh, water, and what looks like engineered tunnels for said water, I wonder what these could be?"

None of that imaginary scenario of yours needs to happen, because these things have been working for thousands of years, and the people that built them wrote down their methods, and their life stories in some some cases. And the thousands of people who would die in a desert if it weren't for this infrastructure bringing them water every day still know exactly how they work, because they go inside them once a year or so to clean them out. I have nothing but admiration for the gigantic engineering feat it took to create these marvels in a pre-industrial society, which is why I spend a fair amount of my limited free time learning about them. And explaining technical details to a general audience is not always the same thing as glossing over.
posted by seasparrow at 5:30 PM on April 24, 2016 [3 favorites]


I found a poster abstract from the same researchers from the EGU general assembly last week, which mentions how "GIS and spatial analyses provided new information on the relationship between the puquios, settlement patterns, and geoglyphs" so it could just be that the main news here is they've found strong indications that these things were built by the Nasca and were much more extensive than what's left of them today (cf how the puquios are described in Wikipedia).
posted by effbot at 5:39 PM on April 24, 2016 [5 favorites]


seasparrow, with your front door/side door analogy, are you saying the wind acts as suction, pulling the water rather than pushing? I'm still not understanding the role played by the wind vs the role played by gravity here.
posted by LobsterMitten at 5:42 PM on April 24, 2016


When you dig a tunnel underground without ventilation, even if the air can exit at the entrance, it tends not to. The air doesn't move. If humans go inside, there is a real chance that carbon dioxide will dangerously pool in the lower sections of the tunnel. This is why modern mines have ventilation tunnels perpendicular to the main working shafts, and also the lesson the ancient qanat builders independently learned. Having the ventilation tunnels in a qanat or puqio just gets the air flowing out of the entrance of the tunnel, which also helps the water to flow. Upon reflection, I could also have used the analogy of poking a hole in the other end of a can of beer so that it flows out quicker while one frat-boy holds it upside down over the mouth of another frat boy.

The wind just creates an opening at the mouth of the tunnel that helps the water flow, and protects humans who enter the tunnel from suffocating. But gravity still does almost all the work in actually moving the water, through the very gentle slope of the tunnel.
posted by seasparrow at 5:50 PM on April 24, 2016 [9 favorites]


Hmm, revisiting one of my old links, I see that the Iranian scientists and historians who know the most about qanats have recently coined the English term "Historic Hydraulic Structures" as a catch-all phrase. I think that is charming and awesome.

And I think it would be great if it turns out that this new data conclusively shows that the Nazca were the original builders of the puqios. I only meant to write earlier that the Spanish definitively knew and used this technology, so until now we couldn't conclusively rule out that they didn't build the structures. I will be watching for further developments with interest.
posted by seasparrow at 6:06 PM on April 24, 2016 [3 favorites]


no matter who built them, can we all agree that this earthmoving technique is much better than the US (and now chinese) penchant for giant dams?
posted by eustatic at 6:34 PM on April 24, 2016 [2 favorites]


The original artical is from BBC Future and says: The puquios were a “sophisticated hydraulic system constructed to retrieve water from underground aquifers,...”


So they're well entrances like others have said above; wonderously engineered in sand with rounded stones. No weird wind/water pushing crap. No underground tunnels stretching for miles from the mountains to the desert. The only canals are carrying water to the fields.

These things are going on my bucket list.
posted by bonobothegreat at 6:55 PM on April 24, 2016


uuuuuzumakiiiiii @@@
posted by gusandrews at 7:14 PM on April 24, 2016 [1 favorite]


Bonobothegreat, your assertation is not supported by the scientific evidence. The puqios are indeed tunnels, the updated wikipedia entry calls them underground aqueducts, and another recent article describes a "network of caves and tunnels." The unique spiral holes are ventialtion tunnels, as seen elsewhere in the world in similar artifacts. Standing on a plain in Iraq, and seeing the evenly spaced dots of the individual excavations stretching away to the mountains, I immediately understood that these shafts were also used during construction to keep the tunnels straight.
posted by seasparrow at 7:18 PM on April 24, 2016


seasparrow, do you have insight into the cave cities of Cappadocia, like Derinkuyu? It says they have a very effective, passive ventilation. But noone gives enough information to try and duplicate it. Having fresh air deep underground, with no moving parts and no electricity, is an AWESOME technology!
posted by Ted Walther at 7:28 PM on April 24, 2016


i know everyone thinks the ancient aliens shit is so hilarious and everything but it's some fundamentally racist bullshit based on erasing the accomplishments of nonwhite civilizations and i'd love to never ever see it again, thanks.

I hadn't really thought of it in these terms, but I think this is accurate. This story is such a fantastic example of why the ancient aliens stuff frustrates me so much. People are so willing to sell themselves short. I look at stuff like this and think about how old we are as a species and think "wow, imagine all of the things we've accomplished, all of our inventions between the day our first ancestor hit the floor of the serengeti to today. I'm one of the latest models of the most incredible thing to ever walk this planet" while they debate which alien group taught us about semiconductors because obviously that's too complicated for us to develop on our own. It makes me sad and angry at the people making money off of it.
posted by feloniousmonk at 7:37 PM on April 24, 2016 [2 favorites]


I don't know enough about it to argue about with you seasparrow, it but it seemed to me like the Science Alert article added a layer of woo to the BBC artical. I can't speak to the wiki entry but I don't know how it can claim they're aqueducts, then say in the next sentence that none have been excavated and it uses the term aquifer at the end, so maybe people have their terms mixed up?
posted by bonobothegreat at 7:57 PM on April 24, 2016


I have visited several of the cave cities in Cappadocia in the early 1980s on a tour with my parents, when I was a teenager, but I don't have any special pneumatic or hydraulics expertise. I do know from observation that the rock there was so soft that is was easy to mine, and I saw many vertical ventilation shafts.

Bonobothegreat, I don't know either. I have never been to South America, and I only know what I see from the articles. The bulk of my research and all of my site visits (made during my free time from regular duties) have been in the middle east, with some additional research (but no visits) on North African and Mexican iterations of the system. The technical terms used in the writing is that the aquifer in the mountains holds the water, and the qanat tunnels bring the water from the aquifer to where ever its outlet is. So it is not impossible that what you read and what I described are in fact the same thing, but I certainly could be wrong, and realize it isn't worth arguing about.

I see that the overhead pattern of the spiral-form shafts in Peru resembe the vents of the qanats in the old world, which I know to be in a line of tunnels connected together. I am not an expert, not an engineer, just a person really fascinated by this ancient technology. I am excited about this new discovery, and want to know what the real experts have discovered. I am sorry if some of my earlier replies were argumentative.
posted by seasparrow at 8:24 PM on April 24, 2016 [2 favorites]


seasparrow: I was using Google Earth to check the elevation at Derinkuyu. I was thinking, if it is inside a mountain, it could vent at the base, problem solved. Instead, it is at the bottom of a basin, looks a bit like a flood plain. The air exchange... love to know how that is done. Carbon dioxide is heavier than air. And the description of the ventilation system describes fresh air; so, probably not dependant on heat from the humans to "push" stale air upwards and draw new air in at the bottom.
posted by Ted Walther at 8:35 PM on April 24, 2016


Ones I saw (not in Peru) had the ventilation shafts drawing air in at higher elevations, and then moving through the slightly sloping passage, and ending with a very slight breeze exiting out of the outlet of the tunnel. The article at waterhistory.org has a description of airflow in a system where a "wind tower" is sited over a qanat ventilation shaft:

"Hot dry air enters the qanat through one of its vertical shafts (a) and is cooled as it flows along the water. Since the underground water is usually cold, the rate of cooling is quite high. The wind tower is placed so that wind flowing through the basement door of the tower passes over the top of the qanat tunnel. When the air flows from a large passage (the tunnel) through a smaller one (the door), its pressure decreases. The pressure of the air from the tower is still diminished when it passes over the top of the tunnel, so that cold moist air from the shaft is entrained by the flow of cooled air from the tower (c). The mixture of air from the qanat and air from the tower (d) circulates through the basement. A single qanat can serve several wind-tower systems."

Also poked around in my bookmarks and found this copy of a 1968 Smithsonian article on qanats that is better than I remembered, although in the last 48 years some new scholarship has obviously been done. But it has some nice discussion on the social customs and laws that grew up around these structures, as well as interesting details of construction and surveying.
posted by seasparrow at 9:21 PM on April 24, 2016 [3 favorites]


Aliens-actually-did-it-instead-of-nonwhites is totally racist but it seems worth noting that ancient astronauts stuff is sometimes advancing an idea that a non-Western civilization on its own was more sophisticated than its Western counterparts; for example if you Google "vedic ancient technology" I think at least some of the results you get are claims by modern South Asians asserting that the Veda scriptures documented aircraft and spaceflight thousands of years ago.
posted by XMLicious at 9:37 PM on April 24, 2016


Imagine a long pipe with a large cross section carrying water down a moderately steep hill from a big reservoir. The water going down the pipe gives up a lot of potential energy by the time it reaches the bottom, and that energy would go into kinetic energy as it went down the pipe if the water were falling freely, but with a full pipe it can't do that. Instead, it exerts a suction which speeds up water all along the length of the pipe and produces large negative pressures near the top of the pipe, which tend either to produce cavitation within the pipe and slow the rate of flow, or cause the pipe to collapse altogether.

I don't know the slopes, distances, and diameters involved here, but I'd guess that in the case of these buried aqueducts, without the airshafts they would just collapse whenever they got full.
posted by jamjam at 9:38 PM on April 24, 2016 [1 favorite]


I read this and was frustrated with the the whole 'wind helps pull water up' line because unless there's actual mechanical action driven by the mind (archimedes screw turned by the wind - from the description) there's no way an open system like this could build up enough pneumatic pressure to lift water.
Now, if these are aqueducts, the ventilation tunnels could do the two things mentioned above: 1. Aid flow if the tunnel is filled with water by providing a point of ingress for air to relieve suction/negative pressures (this is just like in the plumbing in your house which has two pipes, one to bring the water away and another to let air in behind the water and take it out of the way as it goes so the water can flow smoothly.) 2. Provides a point to access the water and a way in for cleaning and maintenance.

The spirals are cool but (to my entirely un-trained eye and my actual experience as a plumber) would have minimal effects on the working/movement of the water in the tunnels.

I especially appreciated the descriptions of the roofs being, in places, of wood. It gives a better understanding of the construction of these things (dig a trench, cover it, then bury it.) This is all very fascinating and cool I look forward to reading more about it.
posted by From Bklyn at 12:47 AM on April 25, 2016 [1 favorite]


There are vents in the City Creek Canyon water pipes that deliver water to Salt Lake City. They use the vents as the water pipes gradually reduce in volume to make city pressure. The air bubbles in the water get compressed in this process, and need a route for exit so the water volume is without air bubbles in order to achieve maximum pressure for delivery to taps.

First the aquifer water is busy flowing through ground and gravel, and over what ever sort of rock under layer. Then the air bubbles need to exit, the vents of all ancient types, facilitate this. The release of air from the downward flowing water, assists in reducing the volume of liquid to its smallest diameter. It could be that reducing the air in, and cooling the water with underground flow, reduces the aerobic bacterial content.
posted by Oyéah at 9:52 AM on April 25, 2016 [1 favorite]


i know everyone thinks the ancient aliens shit is so hilarious and everything but it's some fundamentally racist bullshit based on erasing the accomplishments of nonwhite civilizations and i'd love to never ever see it again, thanks.

The ancient aliens thing is bullshit and based on some really, really bad science (for lack of a better term) but I don't think the racism card is called for here. The theory is also used to explain all kinds of western European megaliths by what could be called the original white people. It is the kind of bullshit that is demeaning to everyone and is the result of 'turtles all the way down' thinking and a legacy of religious 'gifts from god' and original sin crap.
posted by bartonlong at 3:49 PM on April 25, 2016


The theory is also used to explain all kinds of western European megaliths by what could be called the original white people

I see your point; it might be more precise to restate the claim of "racist bullshit" by noting that the "ancient aliens" discourse tends to erase forms of knowledge that are not encoded in modern/Western paradigms?

oh god I have unironically used the words discourse and paradigm in one sentence and feel deep shame for it
posted by tivalasvegas at 4:17 PM on April 25, 2016


but I don't think the racism card is called for here

[muffled immigrant song screaming in the distance]
posted by poffin boffin at 4:34 PM on April 25, 2016 [2 favorites]


Here is a trip through the Turfan water system in the Uyghur area. Thought to be technology brought along the Silk Road from Muslim Persia to what is now northern China.

Watch the whole documentary for more irrigation and general wonderment!
posted by asok at 3:41 AM on April 26, 2016 [1 favorite]


The video linked above features a working karez/qanat being visited via one of the well holes. There are people working in the tunnel clearing debris. The film crew then descend on the oxen powered lifting device into to the tunnel and follow the water down hill to the oasis town of Turfan.

I wonder if the swirly patterns in the Peruvian well holes were somehow used to lift things or people in and out of the tunnels?
posted by asok at 5:44 AM on April 26, 2016 [1 favorite]


I just want to thank the folks who were actually more knowledgeable than me and graciously chimed in. I especially enjoyed those comments.
posted by Michele in California at 11:40 AM on April 29, 2016


« Older Stars reign down - on you   |   “I truly love keeping the wolf from the lambs.” Newer »


This thread has been archived and is closed to new comments