Editing v0.34:Water

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{{Quality|Exceptional|19:08, 6 July 2010 (UTC)}}

'''Water''' is a fluid found all over the world. It [[flow|flows]] from mountain springs, forming the world's [[ocean]]s, [[lake]]s, [[river]]s, and [[brook]]s. Water falls as [[rain]] and [[snow]], and freezes into [[ice]]. Water is home to a variety of [[creature|aquatic creatures]]. Many creatures can [[Swimmer|swim]] in deep water. Air-breathing creatures that are submerged in water can [[Swimmer#Drowning|drown]] in it. Water comes in two varieties: '''freshwater''', which makes up almost all inland water, and '''saltwater''', which fills the seas.  In this version, some brooks and murky pools can be saltwater even if the fortress site is partially mountainous.  It is not known if this is a bug.  To tell the difference, attempt to set up a drinking zone including some of the water in question.  If there are zero tiles of water source available, the water is saltwater.

Mud is a [[contaminant]] which is created any time water covers an area. Any tiles that contain mud may be used for [[Agriculture|farming]].

Water can be displayed in two ways, depending on the [[Technical tricks#The look of the game|settings]] in d_init.txt. By default it is displayed with the symbols {{Tile|≈|1:7:1}} and {{Tile|~|1:7:1}}, sometimes colored different blues, and white, showing ripples, and flow. Setting <nowiki>[SHOW_FLOW_AMOUNTS:YES]</nowiki> in d_init.txt will cause water to display using a depth indicator of {{Tile|1|1:0:1}} through {{Tile|7|1:0:1}} instead. Water can also take on other colors indicating [[contaminant|contaminants]] such as '''blood''', '''ichor''', or '''goo'''.

Dark-colored water symbols indicate the water is one [[Z-level]] below the camera level. Water has 7 depth levels per tile, with 1 being a shallow puddle, and 7 filling the tile completely. [[Dwarf|Dwarves]] can safely walk through water up to a depth of 3 - at depth 4 or higher, a dwarf will cancel jobs due to "Dangerous terrain" and begin to gain [[swimming]] experience. At depth 7, any dwarf that does not have sufficient Swimming skill will drown.

Interestingly, water can slow falls with deep enough water and short enough falls. If the water is deep enough relative to the height of the fall, dwarves can be less injured or even completely uninjured (from a 4 level drop to a 3 level deep pool, for example)

== Processes ==
===Evaporation===
In the normal underground temperature of {{ct|10015}}, evaporation occurs when water or [[magma]] is at a depth of 1/7. Exact rate of evaporation is unknown, but it is affected by temperature and surrounding liquids. A single 1/7 water tile will evaporate faster than a large recently flooded area or a 1/7 water tile by a river, for example.

At high temperatures (usually found in [[Climate#Scorching|Scorching climates]]) water can evaporate at greater depths, even 7/7. This is generally accompanied by the [[grass]] drying out and turning yellow.


{| style="border-spacing:0; float:left; margin-right:10px;"
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|{{CCC}}
|{{RT0|1|#00F}}
|{{RT0|1|#00F}}
|{{RT0|1|#00F}}
|{{CCC}}
|-
|{{CCC}}
|{{RT0|7|#00F}}
|{{RT0|7|#00F}}
|{{RT0|7|#00F}}
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Water or magma at 1/7 depth will evaporate even if it is on top of 7/7 depth liquid, as shown in this side-view example.
<br style="clear:both;"/>

=== Freezing and thawing ===
Many environments get cold enough for water to freeze in winter. When this happens, any water that is exposed above ground will [[ice|freeze into ice]]. However, water a single tile away that is in an underground tunnel will not freeze. When ice walls thaw, they always leave a 7/7 water tile regardless of how much water may have been present when the ice formed.

When outdoor water freezes or thaws it does so instantly.  Any dwarf [[swimming]] in water when it freezes will die, and any dwarf standing on a frozen pond will fall into it when it thaws, most likely leading to [[swimmer#Drowning|drowning]] if the dwarf is not an experienced [[swimmer]].

Mining ice can produce chunks of ice.  Taking these chunks into a stone layer will cause it to eventually melt, turning it into a "water" item (much like those hauled in [[bucket]]s) which can't be used for anything. {{Bug|360}}

[[Glacier#Cave-in_some ice_|Caving in an ice wall]] into a stone layer will cause it to instantly melt into water (provided it does not become exposed to the outdoors), which can be used to get water near the surface in a [[glacier]] biome without having to use a [[pump]] stack to pump water up from a [[cavern]] pool.

If you constructed a [[well]] or a [[Grate|floor grate]] right over top of water and it freezes, the item will be deconstructed to its original parts, but some may fall into the water.

==== Freezing point ====
The freezing point of water, {{ct|10000}}, is an important, if not the most important, [[temperature]] in Dwarf Fortress. Below this point, water freezes into ice, and above this point ice will melt into water. A [[biome]] that never dips below this temperature will make obtaining ice next to impossible, and a biome that never rises above this temperature will require underground storage, [[magma]], or an alternative heating method to obtain liquid water.

Although it is most commonly known as the freezing point of water, {{ct|10000}} is also the freezing points of standard [[blood]], ichor, goo, slime, pus, [[milk]], egg white, and egg yolk. [[Nether-cap]]s are naturally constantly at this temperature, but will cause neither water to freeze nor ice to melt. The temperature also acts as the condensation point of [[cave floater]] gas, at which it becomes cave floater juice. As a result of these dependencies, many [[creature]]s will die if they cannot keep their internal body temperature above the freezing point of water.

Below this point, many machine components will not work, instead displaying "Frozen here". This includes [[screw pump]]s, [[windmill]]s, and [[minecart]] rollers. In colder environments, these machines must either be kept indoors or heated with nearby [[fire]] or [[magma]].

== Properties ==
===Depth===
{{Main|Water depth}}
Water can have a depth between 0 and 7.
{| class="wikitable"
|-
! Depth
! Description
|-
| 0
| No water present.
|-
| 1
| Water may evaporate.
|-
| 2
| 
|-
| 3
| 
|-
| 4
| Dangerous terrain. Movement trains [[swimming]].
|-
| 5
|
|-
| 6
| 
|-
| 7
| Risk of drowning. Can have water on floorless tile above.
|}

===Sourced water===
Water that comes from [[aquifer]]s, as well as any water source that extends from the edge of the map ([[river]]s, [[brook]]s, [[ocean]]s, and some [[lake]]s)  is considered to be '''sourced water'''. Any sourced water is an endless supply of water that can never run dry, although it can freeze for part or all of the year in colder biomes. Murky pools, although not 'sourced water' as described here, also slowly generate water during [[rain]] storms. This can make it possible for a murky pool to replenish itself even when it has been completely drained.

When using sourced water you should strongly consider installing [[floodgate]]s and be aware of how [[pressure]] works or you could easily end up [[flood]]ing your fortress and having a lot more [[fun]] than anticipated.

==Flow==
Water and [[magma]] are both fluids which are constantly trying to '''[[flow]]''' into adjacent tiles until they have filled all available space or until they run out of fluid. Fluids technically move in 9 directions: down, and to the sides. Fluids cannot move diagonally up or down. Fluids at a depth of 1/7 no longer attempt to move unless they can move down. Fluids under [[pressure]] can appear to travel upward until the pressure equalizes, though in reality they are moving downward and/or sideways relative to their source.

When water falls onto a tile that is already full, the game will always attempt to move it into a non-full tile on the same [[Z-level]] that can be legally reached (i.e. without going through a wall or other obstruction), even if it has to "teleport" the incoming fluid a long distance to do so. Only when all available tiles are full will incoming water "pile up" on top. This behavior can be exploited to move water long distances very quickly (see "Getting rid of unwanted water" below).

If the flow is strong enough, it can move objects such as dwarves, pets, stones, weapons or corpses. 

Fluids in Dwarf Fortress act like a fairly thick, viscous material. This makes it possible to do highly implausible things like [[pump]] out a dry hole in the middle of a [[river]] or [[ocean]].

== Contamination ==
Water can be contaminated in different ways, both natural and artificial. This contamination can have a negative effect on the water's quality, and can even harm dwarves that ingest it.

===Salt water===
Dwarves cannot use salt water directly; while healthy dwarves will usually prefer to drink [[booze]], wounded dwarves can only be given water to drink, so if you have only salt water on your map it is helpful to desalinate it.

To check to see if water is salty, use the {{k|i}} menu to see if the game shows the pond/pool as a water source. If the "water source (x)" is (0), then the source is salty. If not, then your dwarves will drink it.

A [[screw pump]] can be used to desalinate water.

Dwarves will drink water from a well over salt water, give it to sick dwarves and use it to clean wounds. Even if you do not designate the well as a water source (which is unnecessary anyway), the dwarves will still use it.

=== Stagnant water ===

Water taken from a murky pool or wetlands biome will be stagnant, just as water taken from near the ocean will be salty.  Dwarves get an unhappy [[thought]] if they have to drink stagnant water, and a [[doctor]] cleaning a [[wound]] with stagnant water will have an increased risk of [[Health care#Infection|infection]].

Similar to salt water, [[pump]]ing stagnant water will make it clean. Also, if clean water touches stagnant water, it will destroy stagnant water. <sup>[[DF2012:Release information/0.34.09|0.34.09]]</sup>

The game will describe stagnant water as stagnant if it was in a [[bucket]] or [[flask]]/[[waterskin]], and looking at standing or flowing water with {{K|k}} will indicate whether or not it is stagnant.

=== Water laced with mud ===
If a water source is only one z-level deep and its floor is covered by "a pile of mud" (like most [[cavern|underground pools]]), then any water taken from it will be "water laced with mud".  Drinking water laced with mud will give your dwarves an unhappy thought.  It might also cause [[Health care#Infection|infection]] if used to clean a [[wound]].

Unlike stagnant water, merely moving the water with flow or gravity will take care of the problem, since it only occurs if the water source tile contains "a pile of mud", and water coming into contact with a clean floor only creates "a dusting of mud".

===Contaminants===
Contaminants that get into water currently can do very strange things. A pool of blood that gets covered by water will be pushed out of the water as the water flows creating more pools of blood at the edge of the water. Overflowing a large reservoir that contains contaminants of blood will generate a large amount of blood very quickly. This behavior is thought to be a bug.

==Getting rid of unwanted water==
Water will flow off the edge of the map, endlessly, which is one way to get rid of large amounts of water (evaporation works better with small amounts). Underground, there are at least two ways to accomplish this. One is to channel your excess water into a dry cavern that is open to the map edge, as the water will flow out (depending on slopes, original water level and such). Be careful if you dump the water into an underground lake, as such lakes have some sort of equilibrium built into them, and your excess water may cause them to flood. The other, probably easier method, is to mine to the map edge (since you cannot mine the map edge itself, just up to it), then smooth the edge and then carve [[fortification]]s into it. Water will flow through the fortifications and off the edge of the map. Make sure your exit flow is equal to or, for safety, greater than your input.

Draining lakes and oceans from underneath can be a finicky task, but there's a bit of dwarven magic for it:  build a retractable bridge on the level beneath the sea bottom, with ramps directly underneath it.  Link this to a lever to control the flow as you desire.  Now evacuate the dwarves and wall off the area above the bridge.  Then, with the bridge in place, designate ramps around the bridge leading up - breaking through to the sea bottom.  Now how can the dwarves dig these squares out?  Yep, from beneath the bridge.  In this way they get the water flow started without ever getting their little feet wet.  This is a great way to set up channels one square in from the map edge near a water source, so that you can properly wall off the baddies from getting into the fort.

Due to the way the game handles water flow, making your drainage vertical rather than horizontal whenever possible will drain water much more quickly and efficiently. IE: A tunnel one tile wide and two z-levels deep will drain water considerably faster than a 2 tile wide tunnel on a single z-level.

Dwarves, especially babies, have an almost supernatural talent for finding ways to get washed down drains. Putting [[grate]]s over any drainage holes, no matter how unlikely they seem, will reduce tantrums by grieving parents. Cutting corners by installing floor [[bar]]s will allow child-sized dwarves to fall through, washed away to a whimsical wonderland of underground marvels where they will eventually join the circus, eat cotton candy, and play with delightful clowns. What [[Fun]].

{{gamedata|{{raw|DF2012:hardcoded_materials.txt|MATERIAL|WATER}}}}

{{Category|Physics}}