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Difference between revisions of "v0.31:Aquifer"

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{{quality|Masterwork|15:52, 30 September 2010 (UTC)}}{{av}}
 
{{quality|Masterwork|15:52, 30 September 2010 (UTC)}}{{av}}
An '''aquifer''' is a subterranean layer of {{l|water|groundwater}}-bearing rock or {{l|soil}}. Attempts to mine through the layer will result in the mined-out squares immediately filling with {{l|water}}, effectively halting excavation at or below their level. This, in conjunction with the fact that they are often located in areas rich in {{l|loam}}, and {{l|sand}}, makes it difficult to find great quantities of {{l|stone}} in areas with aquifers, making for more challenging gameplay.
+
An '''aquifer''' is a subterranean layer of [[water|groundwater]]-bearing rock or [[soil]]. Attempts to mine through the layer will result in the mined-out squares immediately filling with [[water]], effectively halting excavation at or below their level. This, in conjunction with the fact that they are often located in areas rich in [[loam]], and [[sand]], makes it difficult to find great quantities of [[stone]] in areas with aquifers, making for more challenging gameplay.
  
Aquifers can't be drained - the groundwater is limitless. {{l|stone detailing|Smoothed}} aquifer stone stops producing water. Aquifers located in {{l|water#Salt_Water|saltwater}} areas will produce salty water. Aquifers do not only produce water - if the incoming water is pressurized, an aquifer tile may instead absorb it. Just like with water production, this ability will not be disabled no matter how much water it absorbs.  
+
Aquifers can't be drained - the groundwater is limitless. [[stone detailing|Smoothed]] aquifer stone stops producing water. Aquifers located in [[water#Salt_Water|saltwater]] areas will produce salty water. Aquifers do not only produce water - if the incoming water is pressurized, an aquifer tile may instead absorb it. Just like with water production, this ability will not be disabled no matter how much water it absorbs.  
  
 
== Where they are found ==
 
== Where they are found ==
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Layers which CAN contain aquifers:
 
Layers which CAN contain aquifers:
*{{L|sandy clay loam}}
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*[[sandy clay loam]]
*{{L|silty clay loam}}
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*[[silty clay loam]]
*{{L|loam}}
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*[[loam]]
*{{L|sandy loam}}
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*[[sandy loam]]
*{{L|silt loam}}
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*[[silt loam]]
*{{L|loamy sand}}
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*[[loamy sand]]
*{{L|silt}}
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*[[silt]]
*{{L|sand (tan)|sand}}
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*[[sand (tan)|sand]]
*{{L|yellow sand}}
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*[[yellow sand]]
*{{L|white sand}}
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*[[white sand]]
*{{L|black sand}}
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*[[black sand]]
*{{L|red sand}}
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*[[red sand]]
*{{L|peat}}
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*[[peat]]
*{{L|pelagic clay}}
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*[[pelagic clay]]
*{{L|calcareous ooze}}
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*[[calcareous ooze]]
*{{L|siliceous ooze}}
+
*[[siliceous ooze]]
*{{L|sandstone}}
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*[[sandstone]]
*{{L|conglomerate}}
+
*[[conglomerate]]
*{{L|puddingstone}}
+
*[[puddingstone]]
 
Layers which CAN'T contain aquifers, despite their names suggesting otherwise:
 
Layers which CAN'T contain aquifers, despite their names suggesting otherwise:
*{{L|clay}}
+
*[[clay]]
*{{L|silty clay}}
+
*[[silty clay]]
*{{L|sandy clay}}
+
*[[sandy clay]]
*{{L|clay loam}}
+
*[[clay loam]]
*{{L|siltstone}}
+
*[[siltstone]]
*{{L|mudstone}}
+
*[[mudstone]]
  
 
== What they do ==
 
== What they do ==
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If you are digging an up/down staircase in the downward direction, and you hit an aquifer, the aquifer tile will be revealed as damp soil or stone, and the digging job will be un-designated for that tile.
 
If you are digging an up/down staircase in the downward direction, and you hit an aquifer, the aquifer tile will be revealed as damp soil or stone, and the digging job will be un-designated for that tile.
  
If you are digging an up/down staircase in the ''upward'' direction, and you hit an aquifer from below, the aquifer tile will immediately start producing water in the stairwell.
+
If you are digging an up/down staircase in the ''upward'' direction, and you hit an aquifer from below, the aquifer tile will immediately start producing water in the stairwell, thus leading to a lot of [[Fun]].
  
 
== Dealing with aquifers ==
 
== Dealing with aquifers ==
  
===Digging at a change in level===
+
===Probing an aquifer===
  
Though an aquifer seems a daunting obstacle, it ''is'' possible to dig through it, given a ample supply of building material (rock or wood) and any unevenness in the depth of the aquifer. The basic facts:
+
You can discover what layer lies below an aquifer layer by digging up/down stairs into the aquifer. This will reveal the tile below the aquifer layer, and if this is non aquifer (for example, clay, ore or bedrock) then you know the aquifer is only 1z deep at that location. This method can only be used to determine whether the aquifer is 1 layer deep, or multiple layers deep, but this is enough to help plan how to penetrate it. Using a pump based method is highly recommended for multiple layer aquifers.
  
* An aquifer layer will ''absorb'' an unlimited amount of water draining in from above.
+
===Going around===
  
* With an up/down stairway or channel designation, a dwarf can break through the floor of the cell ''beneath'' himThat means a dwarf can stand on top of an aquifer layer, dig an up/down stairway, and make it drain into the layer beneath it, if that layer is also an aquifer or has an open path to an aquifer layer nearby.
+
If your embark site is covered by multiple biomes, there is a chance the aquifer is not present in every biome.  In some maps this may be indicated by an outcropping of stone in a landscape otherwise composed of soil; in other maps the change in biome might be visible as a change in soil type or vegetation type or densityYou might be able to dig down through a biome that doesn't have an aquifer, to a Z-level below the aquifer, and then (if you wish) tunnel beneath the aquifer to the previously inaccessible region.
  
* A stairway may be swamped to dangerous levels with water draining in from the squares around it, but many stairways in a clump mean that the drainage to the next layer wins out.
+
Even if all the biomes of your site contain aquifers, they might not all be at the same Z-levelSo you still might be able to dig down in one biome, reaching a Z-level beneath the aquifer in another biome.
 
 
* Constructing a wall, up/down stairway, or channel in an aquifer layer prevents any water from originating in that squareA wall prevents water from draining down into the next layer from any source, while the stairway or channel lets it come in from other squares and drain.
 
 
 
These points support the following method:
 
 
 
# Dig around at the level just above where you encountered the aquifer, placing up/down or down stairways according to your preferred city grid plan.  Training up a few miners in this way will help later.  Spot some points where the next level (as seen from down stairways) varies in wetness from one spot to another.
 
# For the following, pause the game after every square dug out and make sure the miners dig both layers at the same rate and redesignate when they cancel your plans automatically.  Dig a 5x5 hollow square of up/down stairways at the change in level, going down as far as you can.  The lower aquifer should accept water from the upper aquifer, allowing you to drain the upper aquifer (at least partway).  Then gradually take on the area in the middle, building walls and/or staircases to fill in and stop the flow as you expand.  Eventually you should get command over the source of flow, and can dig a hole in the center of the bottom-most layer surrounded by a 3x3 ring of impermeable rock.
 
  
* ''Caveat: sometimes only the top of the aquifer changes depth, but the bottom stays at the same level.  In this case you will get nowhere.  Sometimes the aquifer is two or more layers thick and it doesn't offset enough to let you all the way through - in this case, sometimes you can use the cave-in method to get through one layer, then use this method to get through the next.  And sometimes you'll just find a hole right through when you investigate the change in level, because you're at a biome boundary and it's not aligned perfectly.
+
Additionally, if your biome contains deep cliffs, for instance in the form of a river gorge, it may be possible to build a staircase down the side of the gorge past the aquifer.
  
 
===The ore method===
 
===The ore method===
On maps where the aquifer is not held in a layer of soil, but instead is held in a {{L|sedimentary layer}} such as sandstone, it may be possible to tunnel down through deposits of ore such as magnetite. For this to work you have to find a spot where there is coincidentally an ore deposit on each Z-level you need to dig through.  This is only possible through tiresome trial and error, or through the use of a utility like reveal.exe.  The trial and error method can be accomplished somewhat more easily by digging up/down stairs to reveal the layer underneath them without actually digging into the underlying layer.  This method is more complicated with aquifers located in layers of {{L|conglomerate}}, as large clusters of {{L|puddingstone}} will support the aquifer and thus cannot be used to provide a path through it.
 
  
===The magma/obsidian method===
+
On maps where the aquifer is not held in a layer of soil, but instead is held in a [[sedimentary layer]] such as sandstone, it may be possible to tunnel down through deposits of ore such as [[magnetite]]. For this to work you have to find a spot where there is coincidentally an ore deposit on each Z-level you need to dig through.  This is only possible through tiresome trial and error, or through the use of a utility like reveal.exe. The trial and error method can be accomplished somewhat more easily by digging up/down stairs to reveal the layer underneath them without actually digging into the underlying layer.  This method is more complicated with aquifers located in layers of [[conglomerate]], as large clusters of [[puddingstone]] will support the aquifer and thus cannot be used to provide a path through it.
If you have access to a supply of magma, you can create your own obsidian caissons. By channeling into the aquifer layer and then filling these channels with magma, it is possible to create a wall of obsidian between your working area and the {{l|water}}-bearing rock or {{l|soil}}. However, changes to world generation with the last version have made this method more difficult than it once was, as it is now harder to find magma vents that extend above the aquifer level.
 
  
 
===The cave-in method===
 
===The cave-in method===
If there are enough layers above the aquifer, then letting non aquifer rock fall into the aquifer layer gives an area of diggable rock. This requires at least 2 natural dry layers. If multiple aquifer layers are to be breached, things get more complicated. First {{l| channel}} out the area of aquifer that will be replaced. Then dig out all connecting floors and walls to the block that will fall (build a  support to hold it until you are ready for collision). A {{l| burrow}} may be useful to assign unnecessary dwarves to a safe area. When everyone is clear, de-construct the support with a lever. (If you forgot to bring stone, then you may instead build a constructed floor to support it, designate it to be destroyed, and have a {{l|hospital}} standing ready in case the unlucky one survives.)
 
  
After the collapse, do not dig out the outer edge of the fallen rock.
+
Conceptually this method involves removing the aquifer-bearing sand, soil or rock using channeling, and then dropping an island of dry sand, soil or clay into the resulting pond, a staircase can then be dug through the center of the resulting artificial island. This requires at least 2 natural dry layers.  
  
This does not work with {{l| wood}} walls since they deconstruct on cave-in.
+
This does not work with [[ wood]] walls since they deconstruct on cave-in.
 
 
If you build many rings inside one another in your top drop layer, you can breach multi-level aquifers with as little as 2 natural layers of dry soil above it.  Drop the rings from the outside to the inside using constructed arms to hold the center rings in place.  Once a ring drops into the water below it, pump out the water in the center and dig down another layer.  When that is complete, drop the next ring and continue the process until you are through.  Since you start dropping rings from the outside it is necessary to know how many levels deep the aquifer is before you begin.<br>
 
Tutorial for more than one Aquifier can be found here: [[User:Rhenaya/HowtoDualAquifer]]
 
 
 
Some might regard this method as cheating, so use it at your own risk.
 
  
 
'''Note:''' There is a bug that may prevent this method from working, collapsed layers may turn into the aquifer layer type that was dug out at that level. So, for example: We have three layers, layer 1 has the caving in section, and is not an aquifer. Layer 2 is a dug out layer that is also not a aquifer. And Layer 3 which is dug out and is an aquifer. Now, the bug, say layer 1's cave-in section lands on layer 3's dug out area, sometimes layer 1's caved in section may change into layer 3's soil type. Making it an aquifer too. Thus making the cave-in method impossible for that area.
 
'''Note:''' There is a bug that may prevent this method from working, collapsed layers may turn into the aquifer layer type that was dug out at that level. So, for example: We have three layers, layer 1 has the caving in section, and is not an aquifer. Layer 2 is a dug out layer that is also not a aquifer. And Layer 3 which is dug out and is an aquifer. Now, the bug, say layer 1's cave-in section lands on layer 3's dug out area, sometimes layer 1's caved in section may change into layer 3's soil type. Making it an aquifer too. Thus making the cave-in method impossible for that area.
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*Construct floor tiles to reach the plug and dig through the middle to get under the aquifer. (Slide 6)
 
*Construct floor tiles to reach the plug and dig through the middle to get under the aquifer. (Slide 6)
  
===The freezing method===
+
====Cave-In Method for Multiple Layers====
  
If you are playing in a freezing or very cold landscape, where it snows in winter and instantly freezes water on the map, you can dig out a 3x3 hole in the ground using {{l|channel}}s, and make it deeper and deeper until you reach the aquifer level. Once you reach the damp rock, tunnel into it with an up/down staircase - the incoming water will freeze after a few moments. The central square of the 3x3 hole should be tunnelable ice, so you can get to the rock beneath. If there are two aquifer levels, for example, you can just make a larger initial hole, and make a smaller one for the level after.
+
If you build many rings inside one another in your top drop layer, you can breach multi-level aquifers with as little as 2 natural layers of dry soil above it. Drop the rings from the outside to the inside using constructed arms to hold the center rings in place. Once a ring drops into the water below it, pump out the water in the center and dig down another layer. When that is complete, drop the next ring and continue the process until you are through. Since you start dropping rings from the outside it is necessary to know how many levels deep the aquifer is before you begin.<br>
 
+
Tutorial for more than one Aquifier can be found here: [[User:Rhenaya/HowtoDualAquifer]]
If your fortress is in a zone that gets warm, build walls around the inside of the hole to stop the water coming in once the ice melts.
 
 
 
<b>Note</b>: There is a bug that may prevent this from working, sometimes ice walls don't produce an ice floor tile above them, instead leaving it as "open space" which prevents the player from digging downwards.  
 
Simplest method is to construct a wooden (or stone, if you have any) floor and then remove it. After the floor is removed, a natural ice floor will remain.
 
An alternative means that will work is to set the tile 1 z-level '''ABOVE''' your missing ice floor tile as a {{l|pond}}, and '''FILL IT'''. The first {{l|bucket}} of water that goes on it will create that missing ice floor tile the instant the water is dumped on it, and you will receive a cancellation message that the pond has gone away. Dezone the pond {{l|activity zone}}, and get back to work breaching that ice. Keep in mind that you will need an '''unfrozen water source''' to use to fill your bucket, so have a working {{l|well}} or underground pond ready beforehand for this to work.
 
  
 
===The pump method===
 
===The pump method===
  
The pumping method uses multiple {{L|screw pump|pumps}} to keep an area dry long enough to smooth or {{l|wall}} off the edges, stopping the flow of water.  It requires no special environment or resources, other than wood and dwarves (and patience).  Most commonly, a moderately sized section of the aquifer layer is channeled out and several screw pumps are built facing it.  Directly behind each of the screw pumps a few tiles are channeled out to receive and dispose of the pumped water.  When the pumps are activated, they should pump water faster than the aquifer can produce it, allowing masons to smooth or build walls around your future staircase.  You ''will'' get job cancellations during this process, as stray 2/7's of water interrupt the building process.  Just unsuspend the construction when this happens, as long a dwarf manages to touch the wall before canceling, it will move incrementally toward completion and eventually finish.  Depending on the availability of screw pumps and dwarves, you may need to wall off one corner or side at a time, then move the pumps and repeat.  When drilling through more than one aquifer layer, be sure to leave yourself enough room to build additional layers of pumps and water disposal channels on lower levels.  
+
The pumping method uses multiple [[screw pump|pumps]] to keep an area dry long enough to smooth or [[wall]] off the edges, stopping the flow of water.  It requires no special environment or resources, other than wood and dwarves (and patience).  Most commonly, a moderately sized section of the aquifer layer is channeled out and several screw pumps are built facing it.  Directly behind each of the screw pumps a few tiles are channeled out to receive and dispose of the pumped water.  When the pumps are activated, they should pump water faster than the aquifer can produce it, allowing masons to smooth or build walls around your future staircase.  You ''will'' get job cancellations during this process, as stray 2/7's of water interrupt the building process.  Just unsuspend the construction when this happens, as long a dwarf manages to touch the wall before canceling, it will move incrementally toward completion and eventually finish.  Depending on the availability of screw pumps and dwarves, you may need to wall off one corner or side at a time, then move the pumps and repeat.  When drilling through more than one aquifer layer, be sure to leave yourself enough room to build additional layers of pumps and water disposal channels on lower levels.  
  
 
Things to consider:  
 
Things to consider:  
 
* Flowing water will cause parents to drop their infants, leading to job cancellations and occasionally [[fun]].
 
* Flowing water will cause parents to drop their infants, leading to job cancellations and occasionally [[fun]].
* Mechanical {{l|power}} may come in handy, but dwarf power works just fine and is much more portable.
+
* Mechanical [[power]] may come in handy, but dwarf power works just fine and is much more portable.
 
* Channels can sometimes be used in place of walls, causing water produced by by the aquifer on one level to immediately fall and be consumed by the aquifer on the level below.
 
* Channels can sometimes be used in place of walls, causing water produced by by the aquifer on one level to immediately fall and be consumed by the aquifer on the level below.
 
* This method may take a while.
 
* This method may take a while.
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Two [http://www.bay12forums.com/smf/index.php?topic=79224.0 pump-based implementations] have been tested and found to meet dwarven standards of excellence. <!-- At some point, put these on the wiki directly. -->
 
Two [http://www.bay12forums.com/smf/index.php?topic=79224.0 pump-based implementations] have been tested and found to meet dwarven standards of excellence. <!-- At some point, put these on the wiki directly. -->
 +
 +
===The freezing method===
 +
 +
If you are playing in a freezing or very cold landscape, where it snows in winter and instantly freezes water on the map, you can dig out a 3x3 hole in the ground using [[channel]]s, and make it deeper and deeper until you reach the aquifer level. Once you reach the damp rock, tunnel into it with up/down staircases, then channel out the downstairs, the exposed water will turn to ice, digging the up/downstairs before channeling allows the tiles to safely fill with 7/7 water before being frozen, this avoids the hazard of miners being encased in ice and avoids a bug(?) where frozen water which is less than 7/7 deep does not produce a floor above it. The central square of the 3x3 hole should be tunnelable ice, so you can get to the rock beneath.
 +
 +
If your fortress is in a zone that gets warm, build walls around the inside of the hole to stop the water coming in once the ice melts. In order to build a wall around a 1x1 staircase it will be necessary to have a 5x5 hole, since you need to leave an outer ring of ice to seal the aquifer.
 +
 +
If the aquifer is multiple layers deep you will need to start with a sufficiently large hole to account for both an ice wall to seal the aquifer and a constructed wall to seal the ice wall for each layer of the aquifer. A pump based method might be preferable.
 +
 +
===The magma/obsidian method===
 +
 +
If you have access to a supply of magma, you can create your own obsidian caissons. By channeling into the aquifer layer and then filling these channels with magma, or by digging staircases and pouring magma down the staircases, it is possible to create a wall of obsidian between your working area and the [[water]]-bearing rock or [[soil]]. However, changes to world generation with the last version have made this method more difficult than it once was, as it is now harder to find magma vents that extend above the aquifer level.
 +
 +
===The drainage method===
 +
 +
Having made an initial hole in the aquifer, you may wish to punch another larger hole through, say for example to grow wild strawberries in the caverns. Or you may simply want an additional (natural stone!) staircase. Once you have access from below this is much easier than digging from above, and it has the additional benefit of producing a shaft of exactly the size you want.
 +
 +
Locate the caverns and dig a drainage shaft of up/down stairs or downward stairs up from the caverns to the aquifer (downward stairs function as grates and are far safer than channeling). Once the drainage shaft is complete punch the shaft up through the aquifer (using up/down stairs) until you hit dry dirt. Now mine out the walls around the shaft and build constructed walls to seal the aquifer. It's even faster if the walls are channeled out instead, constructed walls can be built in the open space and water falls straight through, thus construction can always be started and is never suspended. Always build the walls from the highest layer down, so the dwarves aren't having water dumped on them from above.
 +
 +
This method can be used to create arbitrarily large (and shaped) holes. Large holes, which would be impractical to dig from above, are very easy using this technique. It's also extremely useful for digging straight shafts through "layercake" aquifers where aquifer tiles and non-aquifer tiles are intermixed.
  
 
===The modding method===
 
===The modding method===
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By editing the the raws and removing the [AQUIFER] tag from all of the appropriate entries in inorganic_stone_layer.txt, inorganic_stone_mineral.txt, and inorganic_stone_soil.txt it is possible to remove all aquifers from the world.  This can be done before creating a new world or after, if you find a particularly neat location ruined only by the presence of an aquifer. In order to modify an existing world, you must delete the [AQUIFER] tag from the raws in the savegame's folder.
 
By editing the the raws and removing the [AQUIFER] tag from all of the appropriate entries in inorganic_stone_layer.txt, inorganic_stone_mineral.txt, and inorganic_stone_soil.txt it is possible to remove all aquifers from the world.  This can be done before creating a new world or after, if you find a particularly neat location ruined only by the presence of an aquifer. In order to modify an existing world, you must delete the [AQUIFER] tag from the raws in the savegame's folder.
  
===Digging with help from below===
+
=====Command-line (Linux)=====
  
So say you sneak down below the aquifer through an ore vein or something, but you still want to punch a tunnel through a part of the aquifer that does ''not'' afford such luxury. With a typical double-layer aquifer (with an unsafe layer beneath it that fills from above) it is not easy to push through a stairwell where you'd like, even if you have access to the space beneath.  Start by ensuring 24 building materials (wood or stone) are available close by on the layer above the top aquifer, and that a ''large'' space (at least 25x25 or so, preferably larger) is available on the top safe layer under the aquifer, four layers beneath the first.    Dig or build an up-down stair at the same position on the upper and lower safe levels, and surround the top up-down stair with 8 down-stairs for better access.  Have at least three legendary diggers and half a dozen moderately skilled masons close by and idle.  It also helps to have a stairway or open space leading down from the lower level to relieve water buildup at the point you'll make the hole.
+
cd df_linux/raw/objects/
 +
sed -i 's/\[AQUIFER\]/(AQUIFER)/g' inorganic_stone_*.txt
  
Start by digging an up/down stairway upward from the bottom safe stairway into the bottom (third) layerWater will start pouring out into the bottom level.  Designate the next two squares up (on the aquifer levels) as up-down stairs to link the two, and wait until the diggers get started on them.  Then designate a 3x3x3 block around these as up-down stairs on the two aquifer levels and the unsafe level beneath.  Once they're built very large amounts of water will be pouring down into the lower space.  ''Warning:'' unlike in the previous version, diggers now make a habit of canceling designations that they feel they can't get to, such as if the lower level is too flooded for them to approachMake sure all 27 up-down stairs are dug out ASAP.  Then wall six squares on the top level (leaving two to be walled once the corners are filled in), and proceed downward from completed walls until you've walled squares on all three levels.  After you finish, I'm not sure if it's technically necessary to construct up-down stairs in the space you dug out by designation in order to stop all water leakage.
+
and generate worldTo edit an already generated world, run the <code>sed</code> command in the <tt>df_linux/data/save/''regionNN''/raw/objects</tt> folder insteadIf you want to restore the tags later, you can do it with the command:
  
===Going around===
+
sed -i 's/(AQUIFER)/[AQUIFER]/g' inorganic_stone_*.txt
 +
 
 +
=====Text editor (All operating systems)=====
 +
 
 +
Find the files in Dwarf Fortress/raw/objects (new world) or Dwarf Fortress/data/save/''regionNN''/raw/objects (already saved world).
 +
 
 +
Open the three files with a text editor (e.g. Notepad). (inorganic_stone_layer.txt, inorganic_stone_mineral.txt, and inorganic_stone_soil.txt)
 +
 
 +
Use Edit->Replace, and replace [AQUIFER] with (AQUIFER). (Use 'Replace All').
 +
 
 +
To restore the tags later, do the same in reverse. (Replacing (AQUIFER) with [AQUIFER]).
 +
 
 +
== Benefits of aquifers ==
 +
While annoying, aquifers can be useful for building a self-sufficient fortress, and for water-related [[megaprojects]]. Since an aquifer can absorb an infinite amount of water, it can function as a drain for anything above it. For instance, digging a pit in a lower Z level of an aquifer, then connecting it to a breached aquifer a level above through a channel dug a level above ''that'' will create a permanently flowing, compact, secure water/power source completely contained within the fortress. 
  
If your embark site is covered by multiple biomes, there is a chance the aquifer is not present in every biome.  In some maps this may be indicated by an outcropping of stone in a landscape otherwise composed of soil; in other maps the change in biome might be visible as a change in soil type or vegetation type or density. You might be able to dig down through a biome that doesn't have an aquifer, to a Z-level below the aquifer, and then (if you wish) tunnel beneath the aquifer to the previously inaccessible region.
+
Aquifers outside [[ocean]] biomes also contain fresh water. Since aquifers are almost always located close to the surface, freshwater aquifers can easily be turned into a source of infinite, secure, non-freezing drinking water for your dwarves, eliminating the need for a [[cistern]]. While both of these roles can also be filled by [[Caverns|cavern]] features, an aquifer allows you to get the same advantages without exposing yourself to potentially dangerous cavern creatures.
  
Even if all the biomes of your site contain aquifers, they might not all be at the same Z-level.  So you still might be able to dig down in one biome, reaching a Z-level beneath the aquifer in another biome.
+
== External links ==
  
 +
* [http://www.bay12forums.com/smf/index.php?topic=79224.15 QuantumMenace's two-slit method] for breaching aquifers of any depth - Illustrated guide
  
 
{{World}}
 
{{World}}
 
[[Category:World]]
 

Latest revision as of 01:28, 30 June 2012

This article is about an older version of DF.

An aquifer is a subterranean layer of groundwater-bearing rock or soil. Attempts to mine through the layer will result in the mined-out squares immediately filling with water, effectively halting excavation at or below their level. This, in conjunction with the fact that they are often located in areas rich in loam, and sand, makes it difficult to find great quantities of stone in areas with aquifers, making for more challenging gameplay.

Aquifers can't be drained - the groundwater is limitless. Smoothed aquifer stone stops producing water. Aquifers located in saltwater areas will produce salty water. Aquifers do not only produce water - if the incoming water is pressurized, an aquifer tile may instead absorb it. Just like with water production, this ability will not be disabled no matter how much water it absorbs.

Where they are found[edit]

Aquifers are less likely to be found near and in mountains.[Verify]

Layers which CAN contain aquifers:

Layers which CAN'T contain aquifers, despite their names suggesting otherwise:

What they do[edit]

Aquifers are tiles which produce water in their neighboring tiles -- north, south, east, west, and below. They do not produce water in diagonally adjacent tiles, or in the tile above them.

If you are digging an up/down staircase in the downward direction, and you hit an aquifer, the aquifer tile will be revealed as damp soil or stone, and the digging job will be un-designated for that tile.

If you are digging an up/down staircase in the upward direction, and you hit an aquifer from below, the aquifer tile will immediately start producing water in the stairwell, thus leading to a lot of Fun.

Dealing with aquifers[edit]

Probing an aquifer[edit]

You can discover what layer lies below an aquifer layer by digging up/down stairs into the aquifer. This will reveal the tile below the aquifer layer, and if this is non aquifer (for example, clay, ore or bedrock) then you know the aquifer is only 1z deep at that location. This method can only be used to determine whether the aquifer is 1 layer deep, or multiple layers deep, but this is enough to help plan how to penetrate it. Using a pump based method is highly recommended for multiple layer aquifers.

Going around[edit]

If your embark site is covered by multiple biomes, there is a chance the aquifer is not present in every biome. In some maps this may be indicated by an outcropping of stone in a landscape otherwise composed of soil; in other maps the change in biome might be visible as a change in soil type or vegetation type or density. You might be able to dig down through a biome that doesn't have an aquifer, to a Z-level below the aquifer, and then (if you wish) tunnel beneath the aquifer to the previously inaccessible region.

Even if all the biomes of your site contain aquifers, they might not all be at the same Z-level. So you still might be able to dig down in one biome, reaching a Z-level beneath the aquifer in another biome.

Additionally, if your biome contains deep cliffs, for instance in the form of a river gorge, it may be possible to build a staircase down the side of the gorge past the aquifer.

The ore method[edit]

On maps where the aquifer is not held in a layer of soil, but instead is held in a sedimentary layer such as sandstone, it may be possible to tunnel down through deposits of ore such as magnetite. For this to work you have to find a spot where there is coincidentally an ore deposit on each Z-level you need to dig through. This is only possible through tiresome trial and error, or through the use of a utility like reveal.exe. The trial and error method can be accomplished somewhat more easily by digging up/down stairs to reveal the layer underneath them without actually digging into the underlying layer. This method is more complicated with aquifers located in layers of conglomerate, as large clusters of puddingstone will support the aquifer and thus cannot be used to provide a path through it.

The cave-in method[edit]

Conceptually this method involves removing the aquifer-bearing sand, soil or rock using channeling, and then dropping an island of dry sand, soil or clay into the resulting pond, a staircase can then be dug through the center of the resulting artificial island. This requires at least 2 natural dry layers.

This does not work with wood walls since they deconstruct on cave-in.

Note: There is a bug that may prevent this method from working, collapsed layers may turn into the aquifer layer type that was dug out at that level. So, for example: We have three layers, layer 1 has the caving in section, and is not an aquifer. Layer 2 is a dug out layer that is also not a aquifer. And Layer 3 which is dug out and is an aquifer. Now, the bug, say layer 1's cave-in section lands on layer 3's dug out area, sometimes layer 1's caved in section may change into layer 3's soil type. Making it an aquifer too. Thus making the cave-in method impossible for that area.

Cave-In Example[edit]

Note: Side View
  • Dig stairs down to the aquifer. Dig over the aquifer layer but under your "plug". You'll need a 5x5 landmass. (Slide 2)
  • Channel out the area the plug will fall into. (Slide 3)
  • Leave a single floor tile on top of the plug and dig out the outer layer of your plug. The plug should be a 3x3 landmass now. The single floor tile must keep the plug from falling. (Slide 3)
  • Channel out the floor tile holding up the plug. (Slides 4 & 5)
  • Construct floor tiles to reach the plug and dig through the middle to get under the aquifer. (Slide 6)

Cave-In Method for Multiple Layers[edit]

If you build many rings inside one another in your top drop layer, you can breach multi-level aquifers with as little as 2 natural layers of dry soil above it. Drop the rings from the outside to the inside using constructed arms to hold the center rings in place. Once a ring drops into the water below it, pump out the water in the center and dig down another layer. When that is complete, drop the next ring and continue the process until you are through. Since you start dropping rings from the outside it is necessary to know how many levels deep the aquifer is before you begin.
Tutorial for more than one Aquifier can be found here: User:Rhenaya/HowtoDualAquifer

The pump method[edit]

The pumping method uses multiple pumps to keep an area dry long enough to smooth or wall off the edges, stopping the flow of water. It requires no special environment or resources, other than wood and dwarves (and patience). Most commonly, a moderately sized section of the aquifer layer is channeled out and several screw pumps are built facing it. Directly behind each of the screw pumps a few tiles are channeled out to receive and dispose of the pumped water. When the pumps are activated, they should pump water faster than the aquifer can produce it, allowing masons to smooth or build walls around your future staircase. You will get job cancellations during this process, as stray 2/7's of water interrupt the building process. Just unsuspend the construction when this happens, as long a dwarf manages to touch the wall before canceling, it will move incrementally toward completion and eventually finish. Depending on the availability of screw pumps and dwarves, you may need to wall off one corner or side at a time, then move the pumps and repeat. When drilling through more than one aquifer layer, be sure to leave yourself enough room to build additional layers of pumps and water disposal channels on lower levels.

Things to consider:

  • Flowing water will cause parents to drop their infants, leading to job cancellations and occasionally fun.
  • Mechanical power may come in handy, but dwarf power works just fine and is much more portable.
  • Channels can sometimes be used in place of walls, causing water produced by by the aquifer on one level to immediately fall and be consumed by the aquifer on the level below.
  • This method may take a while.
  • Aquifers do not create water in diagonal tiles, but do create water in hollow tiles directly below them. Therefore, you will want to dig two z-levels below the lowest aquifer layer before continuing with your fortress.

Two pump-based implementations have been tested and found to meet dwarven standards of excellence.

The freezing method[edit]

If you are playing in a freezing or very cold landscape, where it snows in winter and instantly freezes water on the map, you can dig out a 3x3 hole in the ground using channels, and make it deeper and deeper until you reach the aquifer level. Once you reach the damp rock, tunnel into it with up/down staircases, then channel out the downstairs, the exposed water will turn to ice, digging the up/downstairs before channeling allows the tiles to safely fill with 7/7 water before being frozen, this avoids the hazard of miners being encased in ice and avoids a bug(?) where frozen water which is less than 7/7 deep does not produce a floor above it. The central square of the 3x3 hole should be tunnelable ice, so you can get to the rock beneath.

If your fortress is in a zone that gets warm, build walls around the inside of the hole to stop the water coming in once the ice melts. In order to build a wall around a 1x1 staircase it will be necessary to have a 5x5 hole, since you need to leave an outer ring of ice to seal the aquifer.

If the aquifer is multiple layers deep you will need to start with a sufficiently large hole to account for both an ice wall to seal the aquifer and a constructed wall to seal the ice wall for each layer of the aquifer. A pump based method might be preferable.

The magma/obsidian method[edit]

If you have access to a supply of magma, you can create your own obsidian caissons. By channeling into the aquifer layer and then filling these channels with magma, or by digging staircases and pouring magma down the staircases, it is possible to create a wall of obsidian between your working area and the water-bearing rock or soil. However, changes to world generation with the last version have made this method more difficult than it once was, as it is now harder to find magma vents that extend above the aquifer level.

The drainage method[edit]

Having made an initial hole in the aquifer, you may wish to punch another larger hole through, say for example to grow wild strawberries in the caverns. Or you may simply want an additional (natural stone!) staircase. Once you have access from below this is much easier than digging from above, and it has the additional benefit of producing a shaft of exactly the size you want.

Locate the caverns and dig a drainage shaft of up/down stairs or downward stairs up from the caverns to the aquifer (downward stairs function as grates and are far safer than channeling). Once the drainage shaft is complete punch the shaft up through the aquifer (using up/down stairs) until you hit dry dirt. Now mine out the walls around the shaft and build constructed walls to seal the aquifer. It's even faster if the walls are channeled out instead, constructed walls can be built in the open space and water falls straight through, thus construction can always be started and is never suspended. Always build the walls from the highest layer down, so the dwarves aren't having water dumped on them from above.

This method can be used to create arbitrarily large (and shaped) holes. Large holes, which would be impractical to dig from above, are very easy using this technique. It's also extremely useful for digging straight shafts through "layercake" aquifers where aquifer tiles and non-aquifer tiles are intermixed.

The modding method[edit]

By editing the the raws and removing the [AQUIFER] tag from all of the appropriate entries in inorganic_stone_layer.txt, inorganic_stone_mineral.txt, and inorganic_stone_soil.txt it is possible to remove all aquifers from the world. This can be done before creating a new world or after, if you find a particularly neat location ruined only by the presence of an aquifer. In order to modify an existing world, you must delete the [AQUIFER] tag from the raws in the savegame's folder.

Command-line (Linux)[edit]
cd df_linux/raw/objects/
sed -i 's/\[AQUIFER\]/(AQUIFER)/g' inorganic_stone_*.txt

and generate world. To edit an already generated world, run the sed command in the df_linux/data/save/regionNN/raw/objects folder instead. If you want to restore the tags later, you can do it with the command:

sed -i 's/(AQUIFER)/[AQUIFER]/g' inorganic_stone_*.txt
Text editor (All operating systems)[edit]

Find the files in Dwarf Fortress/raw/objects (new world) or Dwarf Fortress/data/save/regionNN/raw/objects (already saved world).

Open the three files with a text editor (e.g. Notepad). (inorganic_stone_layer.txt, inorganic_stone_mineral.txt, and inorganic_stone_soil.txt)

Use Edit->Replace, and replace [AQUIFER] with (AQUIFER). (Use 'Replace All').

To restore the tags later, do the same in reverse. (Replacing (AQUIFER) with [AQUIFER]).

Benefits of aquifers[edit]

While annoying, aquifers can be useful for building a self-sufficient fortress, and for water-related megaprojects. Since an aquifer can absorb an infinite amount of water, it can function as a drain for anything above it. For instance, digging a pit in a lower Z level of an aquifer, then connecting it to a breached aquifer a level above through a channel dug a level above that will create a permanently flowing, compact, secure water/power source completely contained within the fortress.

Aquifers outside ocean biomes also contain fresh water. Since aquifers are almost always located close to the surface, freshwater aquifers can easily be turned into a source of infinite, secure, non-freezing drinking water for your dwarves, eliminating the need for a cistern. While both of these roles can also be filled by cavern features, an aquifer allows you to get the same advantages without exposing yourself to potentially dangerous cavern creatures.

External links[edit]

Worlds




Chasm · Desert · Forest · Glacier · Grassland · Lake · Mountain · Murky pool · Ocean · River · Savanna · Shrubland · Tundra · Wetland