In the first three Dune books, where does the water come from to terraform Dune into a non-desert planet? They have the qanats (water tanks/reservoirs), but where does the water come from? Also, aside from spice, what do the Fremen eat? (I doubt they could raise crops with so little water.)

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    IIRC, the water was locked underground as part of the life cycle of the sandworms/sandtrout. Once Leto II disrupted that cycle, the water was released. There might also have been a remark about the Fremen using sealed hydroponic gardens to grow food but I'm not quite sure. Aug 28, 2015 at 8:57
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    im pretty sure that paul/leto 2 where also actively bringing in water from other planets to speed up the teraform process, im pretty sure i remember them ordering guild ships literally filled with water to constantly be coming to dune.
    – Himarm
    Aug 28, 2015 at 14:17
  • @Himarm Madness! I'm sure the Sigma Draconis system harbors comets. Thes Emperors and their money printing devices... Apr 9, 2020 at 21:37

4 Answers 4


Where did the water come from?

The Fremen were collecting water, under the guidance of Dr Pardot Keynes from the atmosphere into secret catch-basins using hidden wind traps.

Station tools began finding their way into the sietch warrens - especially cutterays which were used to dig underground catchbasins and hidden windtraps.

Water began collecting in the basins.

Dune - Appendix I - The Ecosystem of Dune

And from various plants, cactus like in their retention of water:

There was a rare native root plant that grew above the 2,500 meter level in the northern temperate zone. A tuber two meters long yielded half a litre of water.

Dune - Appendix I - The Ecosystem of Dune

The water extracted from the deathstills† would also be available to be added to the catch basins.

When it was done, Muriz clapped his hands once. Attendants came and removed the bodies, taking them to the deathstill where they could be rendered for their water.

The Children of Dune

Sandtrout were also placed into deathstills to extract their water.

And She thought Sandtrout? Many times in this flesh and other had she played the childhood game, poling for sandtrout, teasing them into a thin glove membrane before taking them to the deathstill for their water.

The Children of Dune

This method as well as getting water will also remove some of the Sandtrout that are part of the Spice>Sandtrout>Sandworm cycle. Though this cycle would not be able to be broken until the terraforming of Arrakis begins with vast quantities of water

Using all of these methods Pardot Kynes estimated that it would take:

In the manner of a teacher answering a child who has asked the sum of 2 plus 2, Kynes told them: "From three hundred to five hundred years."

Dune - Appendix I - The Ecosystem of Dune

Following the establishment of a proto-ecosystem of various grasses and a few hardier plants in some protected areas of Arrakis the estimate was locked down a little further:

From the charts emerged a figure. Kynes reported it. Three per cent. If they could get three per cent of the green plant element on Arrakis involved in forming carbon compounds, they'd have their self-sustaining cycle.

"But how long?" the Fremen demanded.

"Oh, that: about three hundred and fifty years."

Dune - Appendix I - The Ecosystem of Dune

Then came Muad'dib, who upon becoming emperor increased the pace of water collection to create the terraforming needed for the vision of the golden path he had, including the use of weather satellites to bring rain. This was taken up by Leto after his father could not continue on the golden path, until only a small personal desert, the Sareer, was left in God Emperor of Dune.

As for food.

There is the Muad'dib mouse that Paul took his Fremen name from, this could be eaten, as could anything that preys on it.

There are also carrion birds mentioned by Liet Keynes

There are carrion eater birds over me. Perhaps some of my Fremen will see them and come to investigate.


These again could be eaten, and presupposes there is an active enough ecosystem on Arrakis to support them.

Plants are shown to be tended in the sietches using plastic sills to gather water and funnel them to the roots.

One could also guess that mushrooms would grow in the various caves that make up a sietch.

Following the establishment of the nascent ecosystem the following fauna and flora were introduced:

They turned then to the necessary animal life - burrowing creatures to open the soil and aerate it: kit fox, kangaroo mouse, desert hare, sand terrapin . . . and the predators to keep them in check: desert hawk, dwarf owl, eagle and desert owl; and insects to fill the niches these couldn't reach: scorpion, centipede, trapdoor spider, the biting wasp and the wormfly . . . and the desert bat to keep watch on these.

Now came the crucial test: date palms, cotton, melons, coffee, medicinals - more than 200 selected food plant types to test and adapt

Dune - Appendix I - The Ecosystem of Dune

All of which would conceivably be used to supplement their existing diet.

a machine used to extract water from a body, usually dead, though the person can be alive when used as Fremen capital punishment

  • I would add that as I recall, there's a bit in the Appendix in Dune where Kynes studies Arrakis and notes that obviously there had once been a great deal of water on the planet, and that while much of it had been removed somehow, not all of it was. From here the appendix discusses the discovery of the lifecycle of the sandworm and how it sequesters water.
    – Broklynite
    Feb 5, 2016 at 12:21
  • @Broklynite I toyed with that but the question doesn't ask where has the water gone, but where does the water come from and what are the Fremen eating. If I can make it fit within the question i'll put it in, but didn't think it was relevant to what was asked... actually i think i know where it can fit. Thanks! Feb 5, 2016 at 12:29
  • Hm, you make a good point. I suppose I read it as a broader question of the water cycle, but it doesn't actually ask that.
    – Broklynite
    Feb 5, 2016 at 12:40
  • In addition to the water sequestered in the sand trout & catch basins, there's fresh water in the polar ice caps on Arrakis.
    – RobertF
    May 11, 2016 at 14:31

The sandtrout encapsulates free water, binding it. Once sandtrout starts dying in numbers that water gets released.

As for food: the Fremen trap water, mainly from the atmosphere, and presumably use that for irrigation or hydroponics.

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    -1 you didnt explain, A. how or why the sandtrout are dying to release water, and B. how or if, the fremen actually had enough water saved up to terraform an entire planet.
    – Himarm
    Aug 28, 2015 at 14:19
  • @Himarm The sandtrout aren't actually the ones doing the dying, at least not directly. Water is toxic to the adult sandworm, however, and sandtrout are (I think) their offspring. So if you kill enough sandworms, the supply of sandtrout starts to dwindle. Aug 28, 2015 at 15:26
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    @DougWarren the point is where did they get enough water to make the entire planet wet, that wasn't answered here, which is what the question is about. despite killing all of the sandworms, the planet still literally does not have enough water to have full on rivers, lakes ect. so thats the part of the question i haven't seen adequately addressed.
    – Himarm
    Aug 28, 2015 at 15:32
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    @Himarm: what makes you think that the planet doesn't have enough water? The author's premise, if I remember correctly, is that it did - just as much water as any other Earth-like planet. Aug 28, 2015 at 23:46
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    In the appendix to the first book, Pardot Kynes explicitly states that there is enough water. Aug 29, 2015 at 13:44

I don’t think the sandworms and aquifers has much to do with the arrival of water on Arakis. At the end of the film when Paul overcomes the empire and thus becomes emperor, a quick glimpse of the waters of Caladan are shown to the viewer. I believe that Paul, after drinking the water of life, acquired the ability to bend space and thus transport water from Caladan to Arrakis with his mind. For a moment there is a shot of Paul looking into the distance as if meditating as the rain arrives.

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    OP was referring to the books, not the awful (awful) film.
    – Valorum
    Apr 9, 2020 at 20:31
  • @Valorum Which one? There have been a couple of awful ones.
    – Spencer
    Apr 9, 2020 at 20:48
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    @Spencer - I liked the mini-series. It was a lot truer to the books
    – Valorum
    Apr 9, 2020 at 20:56

Arrakis has enough water locked in the atmosphere, also underground in permafrost. Vast man-made underground cashes were replenished almost exclusively from atmosphere.

Station tools began finding their way into the sietch warrens - especially cutterays which were used to dig underground catchbasins and hidden windtraps. Water began collecting in the basins. (Dune - Appendix I - The Ecosystem of Dune)

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    Is this stated in one of the books? Can you add any references to this answer to support your statement? Sep 29, 2015 at 15:26
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    The ice caps are specifically ruled out by Pardot Keynes in Dune - Appendix I - "The polar caps (disregarding the false sense of water security they gave the pyons) held far too small an amount for his project . . ." Oct 23, 2015 at 14:43
  • @Cearon O'Flynn, I mentioned permafrost and atmosphere, you can't see "the ice caps" nowhere in my post.
    – Santa
    Dec 28, 2017 at 16:55
  • @Jason Baker, "Station tools began finding their way into the sietch warrens - especially cutterays which were used to dig underground catchbasins and hidden windtraps. Water began collecting in the basins." (Dune - Appendix I - The Ecosystem of Dune)
    – Santa
    Dec 28, 2017 at 16:56

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