19-1. Introduction. Nearly every
survival account details the need survivors had for water. Many ingenious
methods of locating, procuring, purifying, and storing water are included in the
recorded experiences of downed aircrew members. If survivors are located in
temperate, tropic, or dry climates, water may be their first and most important
need. The priority of finding water over that of obtaining food must be
emphasized to potential survivors. An individual may be able to live for weeks
without food, depending on the temperature and amount of energy being exerted. A
person who has no water can be expected to die within days. Even in cold climate
areas or places where water is abundant, survivors should attempt to keep their
body fluids at a level that will maintain them in the best possible state of
health. Even in relatively cold climates, the body needs 2 quarts of water per
day to remain efficient (Figure 19-1).
Figure 19-1. Water
19-2. Water Requirements.
Normally, with atmospheric temperature of about 68oF, the average
adult requires 2 to 3 quarts of water daily.
a. This water is necessary to replace that lost daily in the following ways:
(1) Urine. Approximately 1.4 quart of water is lost in the urine.
(2) Sweat. About 0.1 quart of water is lost in the sweat.
(3) Feces. Approximately 0.2 quart of water is lost in the feces.
(4) Insensible Water Loss. When the individual is unaware water loss is
actually occurring, it is referred to as insensible water loss. Insensible
water loss occurs by the following mechanisms:
(a) Diffusion through the skin. Water loss through the skin occurs as a
result of the actual diffusion of water molecules through the cells of the
skin. The average loss of water in this manner is approximately 0.3 to 0.4
quart. Fortunately, loss of greater quantities of water by diffusion is
prevented by the outermost layer of the skin, the epidermis, which acts as a
barrier to this type of water loss.
(b) Evaporation through the lungs. Inhaled air initially contains very
little water vapor. However, as soon as it enters the respiratory passages,
the air is exposed to the fluids covering the respiratory surfaces. By the
time this air enters the lungs, it has become totally saturated with
moisture from these surfaces. When the air is exhaled, it is still saturated
with moisture and water is lost from the body.
b. Larger quantities of water are required when water loss is increased in
any one of the following circumstances:
(1) Heat Exposure. When an individual is exposed to very high temperatures,
water lost in the sweat can be increased to as much as 3.5 quarts an hour.
Water loss at this increased rate can deplete the body fluids in short time.
(2) Exercise. Physical activity increases the loss of water in two ways as
(a) The increased respiration rate causes increased water loss by
evaporation through the lungs.
(b) The increased body heat causes excessive sweating.
(3) Cold Exposure. As the temperature decreases, the amount of water vapor
in the air also decreases. Therefore, breathing cold air results in increased
water loss by evaporation from the lungs.
(4) High Altitude. At high altitudes, increased water loss by evaporation
through the lungs occurs not only as a result of breathing cooler air but also
as a result of the increased respiratory efforts required.
(5) Burns. After extensive burns, the outermost layer of the skin is
destroyed. When this layer is gone, there is no longer a barrier to water loss
by diffusion, and the rate of water loss in this manner can increase up to 5
quarts each day.
(6) Illness. Severe vomiting or prolonged diarrhea can lead to serious
c. Dehydration (body fluid depletion) can occur when required body fluids are
(1) Dehydration is accompanied by the following symptoms:
(g) Inelastic abdominal skin.
(h) Dry mucous membranes, that is, dry mouth and nasal passages.
(i) Infrequent urination and reduced volume. The urine is concentrated so
that it is very dark in color. In severe cases, urination may be quite
(2) Companions will observe the following behavioral changes in individuals
suffering from dehydration:
(a) Loss of appetite.
(b) Lagging pace.
(f) Emotional instability.
(g) Indistinct speech.
(h) Mental confusion.
(3) Dehydration is a complication which causes decreased efficiency in the
performance of even the simplest task. It also predisposes survivors to the
development of severe shock following minor injuries. Constriction of blood
vessels in the skin as a result of dehydration increases the danger of cold
injury during cold exposure. Failure to replace body fluids ultimately results
(a) Proper treatment for dehydration is to replace lost body fluids. The
oral intake of water is the most readily available means of correcting this
deficiency. A severely dehydrated person will have little appetite. This
person must be encouraged to drink small quantities of water at frequent
intervals to replenish the body's fluid volume. Cold water should be warmed
so the system will accept it easier.
(b) To prevent dehydration, water loss must be replaced by periodic
intake of small quantities of water throughout the day. As activities or
conditions intensify, the water intake should be increased accordingly.
Water intake should be sufficient to maintain a minimum urinary output of 1
pint every 24 hours. Thirst is not an adequate stimulus for water intake,
and a person often dehydrates when water is available. Therefore, water
intake should be encouraged when the person is not thirsty. Humans cannot
adjust to decreased water intake for prolonged periods of time. When water
is in short supply, any available water should be consumed sensibly. If
sugar is available, it should be mixed with the water, and efforts should be
made to find a local water source. Until a suitable water source is located,
individual water losses should be limited in the following ways:
-1. Physical activity should be limited to the absolute minimum
required for survival activities. All tasks should be performed slowly and
deliberately with minimal expenditure of energy. Frequent rest periods
should be included in the daily schedule.
-2. In hot climates, essential activity should be conducted at night or
during the cooler part of the day.
-3. In hot climates, clothing should be worn at all times because it
reduces the quantity of water loss by sweating. Sweat is absorbed into the
clothing evaporated from its surface in the same manner it evaporates from
the body. This evaporation cools the air trapped between the clothing and
the skin, causing a decrease in the activity of the sweat glands and a
subsequent reduction in water loss.
-4. In hot weather, light-colored clothing should be worn rather than
dark-colored clothing. Dark-colored clothing absorbs the Sun's light rays
and converts them into heat. This heat causes an increase in body
temperatures which activates the sweat glands and increases water loss
through sweating. Light-colored clothing, however, reflects the Sun's
light rays, minimizing the increase in body temperature and subsequent
19-3. Water Sources. Survivors
should be aware of both the water sources available to them and the resources at
their disposal for producing water.
a. Survivors may obtain water from solar stills, desalter kits, or canned
water packed in various survival kits. It would be wise for personnel, who may
one day have to use these methods of procuring water, to be knowledgeable of
their operating instructions and the amount of water they produce.
(1) Canned water provides 10 ounces per can.
(2) Desalter kits are limited to 1 pint per chemical bar - kits contain
eight chemical bars.
(3) A "sea solar still" can produce as much as 2 1/2 pints per
(4) "Land solar stills" produce varied amounts of water. This
amount is directly proportionate to the amount of water available in the soil
or placed into the still (vegetation, entrails, contaminated water, etc.), and
the ambient temperature.
b. Aircrew members would be wise to carry water during their missions.
Besides the fact that the initial shock of the survival experience sometimes
produces feelings of thirst, having an additional water container can benefit
survivors. The issued items (canned water, desalter kits, and solar stills)
should be kept by survivors for times when no natural sources of freshwater are
c. Naturally occurring indicators of water are:
(1) Surface water, including streams, lakes, springs, ice, and snow.
(2) Precipitation, such as rain, snow, dew, sleet, etc.
(3) Subsurface water, which may not be as readily accessible as wells,
cisterns, and underground springs and streams, can be difficult for survivors
to locate and use.
d. Several indicators of possible water are:
(1) Presence of abundant vegetation of a different variety, such as
deciduous growth in a coniferous area.
(2) Drainages and low-lying areas.
(3) Large clumps of plush grass.
(4) Animal trails which may lead to water. The "V" formed by
intersecting trails often point toward water sources.
e. Survivors may locate and procure water as follows:
(1) Precipitation may be procured by laying a piece of nonporous material
such as a poncho, piece of canvas, plastic, or metal material on the ground.
If rain or snow is being collected, it may be more efficient to create a bag
or funnel shape with the material so the water can be easily gathered. Dew can
be collected by wiping it up with a sponge or cloth first, and then wringing
it into a container (Figure
19-2). Consideration should be given to the possibility of contaminating
the water with dyes, preservatives, or oils on the surfaces of the objects
used to collect the precipitation. Ice will yield more water per given volume
than snow and requires less heat to do so. If the Sun is shining, snow or ice
may be placed on a dark surface to melt (dark surfaces absorb heat, whereas
light surfaces reflect heat). Ice can be found in the form of icicles on
plants and trees, sheet ice on rivers, ponds, and lakes, or sea ice. If snow
must be used, survivors should use snow closest to the ground. This snow is
packed and will provide more water for the amount of snow than will the upper
layers. When snow is to be melted for water, place a small amount of snow in
the bottom of the container being used and place it over or near a fire. Snow
can be added a little at a time. Survivors should allow water in the container
bottom to become warm so that when more snow is added, the mixture remains
slushy. This will prevent burning the bottom out of the container. Snow
absorbs water, and if packed, forms an insulating airspace at the bottom of
the container. When this happens, the bottom may burn out.
19-2. Methods of Procuring Water.
(2) Several things may help survivors locate ground water, such as rivers,
lakes, and streams.
(a) The presence of swarming insects indicates water is near. In some
places, survivors should look for signs of animal presence. For example, in
damp places, animals may have scratched depressions into the ground to
obtain water; insects may also hover over these areas.
(b) In the Libyan Sahara, donut-shaped mounds of camel dung often
surround wells or other water sources. Bird flights can indicate direction
to or from water. Pigeons and doves make their way to water regularly. They
fly from water in the morning and to it in the evening. Large flocks of
birds may also congregate around or at areas of water.
(c) The presence of people will indicate water. The location of this
water can take many forms - stored water in containers that are carried with
people who arc traveling, wells, irrigation systems, pools, etc. Survivors
who are evaders should be extremely cautious when approaching any water
source, especially if they are in dry areas; these places may be guarded or
(3) When no surface water is available, survivors may have to tap the
Earth's supply of ground water. Access to this depends upon the type of
ground-rock or loose material, clay, gravel, or sand.
(a) In rocky ground, survivors should look for springs and seepages.
Limestone and lava rocks will have more and larger springs than any other
rocks. Most lava rocks contain millions of bubble holes; ground water may
seep through them. Survivors can also look for springs along the walls of
valleys that cross a lava flow. Some flows will have no bubbles but do have
"organ pipe" joints - vertical cracks that part the rocks into
columns a foot or more thick and 20 feet or more high. At the foot of these
joints, survivors may find water creeping out as seepage, or pouring out in
(b) Most common rocks, like granite, contain water only in irregular
cracks. A crack in a rock with bird dung around the outside may indicate a
water source that can be reached by a piece of surgical hose used as a straw
(c) Water is more abundant and easier to find in loose sediments than in
rocks. Springs are sometimes found along valley floors or down along their
sloping sides. The flat benches or terraces of land above river valleys
usually yield springs or seepages along their bases, even when the stream is
dry. Survivors shouldn't waste time digging for water unless there are signs
that water is available. Digging in the floor of a valley under a steep
slope, especially if the bluff is cut in a terrace, can produce a water
source. A lush green spot where a spring has been during the wet season is a
good place to dig for water. Water moves slowly through clay, but many clays
contain strips of sand which may yield springs. Survivors should look for a
wet place on the surface of clay bluffs and try digging it out.
(d) Along coasts, water may be found by digging beach wells (Figure
19-3). Locate the wells behind the first or second pressure ridge. Wells
can be dug 3 to 5 feet deep and should be lined with driftwood to prevent
sand from refilling the hole. Rocks should be used to line the bottom of the
well to prevent stirring up sand when procuring the water. The average well
may take as long as 2 hours to produce 4 to 5 gallons of water. (Do not be
discouraged if the first try is unsuccessful - dig another.)
Figure 19-3. Beach
19-4. Water in Snow and Ice
Areas. Due to the extreme cold of arctic areas, water requirements are
greatly increased. Increased body metabolism, respiration of cold air, and
extremely low humidity play important roles in reducing the body's water
content. The processes of heat production and digestion in the body also
increase the need for water in colder climatic zones. The constructing of
shelters and signals and the obtaining of firewood are extremely demanding tasks
for survivors. Physical exertion and heat production in extreme cold place the
water requirements of a survivor close to 5 or 6 quarts per day to maintain
proper hydration levels. The diet of survivors will often be dehydrated rations
and high protein food sources. For the body to digest and use these food sources
effectively, increased water intake is essential.
a. Obtaining water need not be a serious problem in the arctic because an
abundant supply of water is available from streams, lakes, ponds, snow, and ice.
All surface water should be purified by some means. In the summer, surface water
may be discolored but is drinkable when purified. Water obtained from
glacier-fed rivers and streams may contain high concentrations of dirt or silt.
By letting the water stand for a period of time, most silt will settle to the
bottom; the remaining water can be strained through porous material for further
b. A "water machine" can be constructed which will produce water
while the survivors are doing other tasks. It can be made by placing snow on any
porous material (such as parachute or cotton), gathering up the edges, and
suspending the "bag" of snow from any support near the fire. Radiant
heat will melt the snow and the water will drip from the lowest point on the
bag. A container should be placed below this point to catch the water (Figure
Figure 19-4. Water
c. In some arctic areas, there may be little or no fuel supply with which to
melt ice and snow for water. In this case, body heat can be used to do the job.
The ice or snow can be placed in a waterproof container like a waterbag and
placed between clothing layers next to the body. This cold substance should not
be placed directly next to the skin; it causes chilling and lowering of the body
d. Since icebergs are composed of freshwater, they can be a readily available
source of drinking water. Survivors should use extreme caution when trying to
obtain water from this source. Even large icebergs can suddenly roll over and
dump survivors into the frigid sea water. If sea ice is the primary source of
water, survivors should recall that like seawater itself, saltwater ice should
never be ingested. To obtain water in polar regions or sea ice areas, survivors
should select old sea ice, a bluish or blackish ice which shatters easily and
generally has rounded corners. This ice will be almost salt-free. New sea ice is
milky or gray colored with sharp edges and angles. This type of ice will not
shatter or break easily. Snow and ice may be saturated with salt from blowing
spray; if it tastes salty, survivors should select different snow or ice
e. The ingesting of unmelted snow or ice is not recommended. Eating snow or
ice lowers the body's temperature, induces dehydration, and causes minor cold
injury to lips and mouth membranes. Water consumed in cold areas should be in
the form of warm or hot fluids. The ingestion of cold fluids or foods increases
the body's need for water and requires more body heat to warm the substance.
19-5. Water on the Open Seas.
The lack of drinkable water could be a major problem on the open seas. Seawater
should never be ingested in its natural state. It will cause an individual to
become violently ill in a very short period of time. When water is limited and
cannot be replaced by chemical or mechanical means, it must be used efficiently.
As in the desert, conserving sweat not water, is the rule. Survivors should keep
in the shade as much as possible and dampen clothing with seawater to keep cool.
They should not over exert but relax and sleep as much as possible.
a. If it rains, survivors can collect rainwater in available containers and
store it for later use. Storage containers could be cans, plastic bags, or the
bladder of a life preserver. Drinking as much rainwater as possible while it is
raining is advisable. If the freshwater should become contaminated with small
amounts of seawater or salt spray, it will remain safe for drinking (Figure
19-5). At night and on foggy days, survivors should try to collect dew for
drinking water by using a sponge, chamois, handkerchief, etc.
19-5. Collecting Water from Spray Shield.
b. Solar stills will provide a drinkable source of water. Survivors should
read the instructions immediately and set them up, using as many stills as
available. (Be sure to attach them to the raft.) Desalter kits, if available,
should probably be saved for the time when no other means of procuring drinking
water is available. Instructions on how to use the desalter kit are on the
c. Only water in its conventional sense should be consumed. The so-called
"water substitutes" do little for the survivor, and may do much more
harm than not consuming any water at all. There is no substitute for water. Fish
juices and other animal fluids are of doubtful value in preventing dehydration.
Fish juices contain protein which requires large amounts of water to be digested
and the waste products must be excreted in the urine which increases water loss.
Survivors should never drink urine - urine is body waste material and only
serves to concentrate waste materials in the body and require more water to
eliminate the additional waste.
19-6. Water in Tropical Areas.
Depending on the time of the year and type of jungle, water in the tropical
climates can be plentiful; however, it is necessary to know where to look and
procure it. Surface water is normally available in the form of streams, ponds,
rivers, and swamps. In the savannas during the dry season, it may be necessary
for the survivor to resort to digging for water in the places previously
mentioned. Water obtained from these sources may need filtration and should be
purified. Jungle plants can also provide survivors with water.
a. Many plants have hollow portions which can collect rainfall, dew, etc. (Figure
19-6). Since there is no absolute way to tell whether this water is pure, it
should be purified. The stems or the leaves of some plants have a hollow section
where the stem meets the trunk. Look for water collected here. This includes any
Y-shaped plants (palms or air plants). The branches of large trees often support
air plants (relatives of the pineapple) whose overlapping, thickly growing
leaves may hold a considerable amount of rainwater. Trees may also catch and
store rainwater in natural receptacles such as cracks or hollows.
Figure 19-6. Water
b. Pure freshwater needing no purification can be obtained from numerous
plant sources. There are many varieties of vines which are potential water
sources. The vines are from 50 feet to several hundred feet in length and 1 to 6
inches in diameter. They also grow like a hose along the ground and up into the
trees. The leaf structure of the vine is generally high in the trees. Water
vines are usually soft and easily cut. The smaller species may be twisted or
bent easily and are usually heavy because of the water content. The water from
these vines should be tested for potability. The first step in testing the water
from vines is for survivors to nick the vine and watch for sap running from the
cut. If milky sap is seen, the vine should be discarded; if no milky sap is
observed, the vine may be a safe water vine. Survivors should cut out a section
of the vine, hold that piece vertically, and observe the liquid as it flows out.
If it is clear and colorless, it may be a drinkable source. If it is cloudy or
milky-colored, they should discard the vine. They should let some of the liquid
flow into the palm of the hand and observe it. If the liquid does not change
color, they can now taste it. If it tastes like water or has a woody or sweet
taste, it should be safe for drinking. Liquid with a sour or bitter taste should
be avoided. Water trapped within a vine is easily obtained by cutting out a
section of the vine. The vine should first be cut high above the ground and then
near the ground. This will provide a long length of vine and, in addition, will
tend to hide evidence of the cuts if the survivors are in an evasion situation.
When drinking from the vine, it should not touch the mouth as the bark may
contain irritants which could affect the lips and mouth (Figure
19-7). The pores in the upper end of the section of vine may reclose,
stopping the flow of water. If this occurs, survivors should cut off the end of
the vine opposite the drinking end. This will reopen the pores allowing the
water to flow.
Water Vines and Bamboo.
c. Water from the rattan palm and spiny bamboo may be obtained in the same
manner as from vines. It is not necessary to test the water if positive
identification of the plant can be made. The slender stem (runner) of the rattan
palm is an excellent water source. The joints are overlapping in appearance, as
if one section is fitted inside the next.
d. Water may be trapped within sections of green bamboo. To determine if
water is trapped within a section of bamboo, it should be shaken. If it contains
water, a sloshing sound can be heard. An opening may be made in the section by
making two 45-degree angle cuts, both on the same side of the section, and
prying loose a piece of the section wall. The end of the section may be cut off
and the water drunk or poured from the open end. The inside of the bamboo should
be examined before consuming the water. If the inside walls are clean and white,
the water will be safe to drink. If there are brown or black spots, fungus
growth, or any discoloration, the water should be purified before consumption.
Sometimes water can also be obtained by cutting the top off certain types of
green bamboo, bending it over, and staking it to the ground (Figure
19-7). A water container should be placed under it to catch the dripping
water. This method has also proven effective on some vines and the rattan palm.
e. Water can also be obtained from banana plants in a couple of different
ways, neither of which is satisfactory in a tactical situation. First, survivors
should cut a banana plant down, then a long section should be cut off which can
be easily handled. The section is taken apart by slitting from one end to the
other and pulling off the layers one at a time. A strip 3 inches wide, the
length of the section, and just deep enough to expose the cells should be
removed from the convex side. This section is folded toward the convex side to
force the water from the cells of the plant. The layer must be squeezed gently
to avoid forcing out any tannin into the water. Another technique for obtaining
water from the banana plant is by making a "banana-well." This is done
by making a bowl out of the plant stump, fairly close to the ground, by cutting
out and removing the inner section of the stump (Figure
19-8). Water which first enters the bowl may contain a concentration of
tannin (an astringent which has the same effect as alum). A leaf from the banana
plant or other plant should be placed over the bowl while it is filling to
prevent contamination by insects, etc.
Water from Banana Plant.
f. Water trees can also be a valuable source of water in some jungles. They
can be identified by their blotched bark which is fairly thin and smooth. The
leaves are large, leathery, fuzzy, and evergreen, and may grow as large as 8 or
9 inches. The trunks may have short outgrowths with fig-like fruit on them or
long tendrils with round fruit comprised of corn kernel-shaped nuggets. In a
nontactical situation, the tree can be tapped in the same manner as a rubber
tree, with either a diagonal slash or a "V." When the bark is cut
into, it will exude a white sap which if ingested causes temporary irritation of
the urinary tract. This sap dries up quite rapidly and can easily be removed.
The cut should be continued into the tree with a spigot (bamboo, knife, etc.) at
the bottom of the tap to direct the water into a container. The water flows from
the leaves back into the roots after sundown, so water can be procured from this
source only after sundown or on overcast (cloudy) days. If survivors are in a
tactical situation, they can obtain water from the tree and still conceal the
procurement location. If the long tendrils are growing thickly, they can be
separated and a hole bored into the tree. The white sap should be scraped off
and a spigot placed below the tap with a water container to catch the water.
Moving the tendrils back into place will conceal the container. Instead of
boring into the tree, a couple of tendrils can be cut off or snapped off if no
knife is available. The white sap should be allowed to dry and then be removed.
The ends of the tendrils should be placed in a water container and the container
g. Coconuts contain a refreshing fluid. Where coconuts are available, they
may be used as a water source. The fluid from a mature coconut contains oil,
which when consumed in excess can cause diarrhea. There is little problem if
used in moderation or with a meal and not on an empty stomach. Green unripe
coconuts about the size of a grapefruit are the best for use because the fluid
can be taken in large quantities without harmful effects. There is more fluid
and less oils so there is less possibility of diarrhea.
h. Water can also be obtained from liquid mud. Mud can be filtered through a
piece of cloth. Water taken by this method must be purified. Rainwater can be
collected from a tree by wrapping a cloth around a slanted tree and arranging
the bottom end of the cloth to drip into a container (Figure
19-9. Collecting Water from Slanted Tree.
19-7. Water in Dry Areas.
Locating and procuring water in a dry environment can be a formidable task. Some
of the ways to find water in this environment have been explored, such as
locating a concave bend in a dry riverbed and digging for water (Figure
19-10). If there is any water within a few feet of the surface, the sand
will become slightly damp. Dig until water is obtained.
Figure 19-10. Dry
a. Some deserts become humid at night. The humidity may be collected in the
form of dew. This dew can be collected by digging a shallow basin in the ground
about 3 feet in diameter and lining it with a piece of canvas, plastic, or other
suitable material. A pyramid of stones taken from a minimum of 1 foot below the
surface should then be built in this basin. Dew will collect on and between the
stones and trickle down onto the lining material where it can be collected and
placed in a container.
b. Plants and trees having roots near the surface may be a source of water in
dry areas. Water trees of dry Australia are a source of water, as their roots
run out 40 to 80 feet at a depth of 2 to 9 inches under the surface. Survivors
may obtain water from these roots by locating a root 4 to 5 feet from the trunk
and cutting the root into 2- or 3-foot lengths. The bark can then be peeled off
and the liquid from each section of root drained into a container. The liquid
can also be sucked out. The trees growing in hollows or depressions will have
the most water in their roots. Roots that are 1 to 2 inches thick are an ideal
size. Water can be carried in these roots by plugging one end with clay.
c. Cactus-like or succulent plants may be sources of water for survivors, but
they should recall that no plants should be used for water procurement which
have a milky sap. The barrel cactus of the United States provides a water
source. To obtain it, survivors should first cut off the top of the plant. The
pulpy inside portions of the plant should then be mashed to form a watery pulp.
Water may ooze out and collect in the bowl; if not, the pulp may be squeezed
through a cloth directly into the mouth.
d. The solar still is a method of obtaining water that uses both vegetation
and ground moisture to produce water (Figure
19-11). A solar still can be made from a sheet of clear plastic stretched
over a hole in the ground. The moisture in the soil and from plant parts (fleshy
stems and leaves) will be extracted and collected by this emergency device.
Obviously, where the soil is extremely dry and no fleshy plants are available,
little, if any, water can be obtained from the still. The still may also be used
to purify polluted water.
Figure 19-11. Solar
(1) The parts for the still are a piece of plastic about 6 feet square, a
water collector-container or any waterproof material from which a
collector-container can be fashioned, and a piece of plastic tubing about
one-fourth inch in diameter and 4 to 6 feet long. The tubing is not absolutely
essential but makes the still easier to use. A container can be made from such
materials as plastic, aluminum foil, poncho, emergency ration tins, or a
flight helmet. The tubing, when available, is fastened to the bottom of the
inside of the container and used to remove drinking water from the container
without disturbing the plastic. Some plastics work better than others,
although any clear plastic should work if it is strong.
(2) If plants are available or if polluted water is to be purified, the
still can be constructed in any convenient spot where it will receive direct
sunlight throughout the day. Ease of digging will be the main consideration.
If soil moisture is to be the only source of water, some sites will be better
than others. Although sand generally does not retain as much moisture as clay,
a wet sand will work very well. Along the seacoast or in any inland areas
where brackish or polluted water is available, any wet soil, even sand,
produces usable amounts of water. On cloudy days, the yield will be reduced
because direct sunlight is necessary if the still is to operate at full
(3) Certain precautions must be kept in mind. If polluted water is used,
survivors should make sure that none is spilled near the rim of the hole where
the plastic touches the soil and that none comes in contact with the container
to prevent the freshly distilled water becoming contaminated. Survivors should
not disturb the plastic sheet during daylight "working hours" unless
it is absolutely necessary. If a plastic drinking tube is not available, raise
the plastic sheet and remove the container as few times as possible during
daylight hours. It takes one-half hour for the air in the still to become
resaturated and the collection of water to begin after the plastic has been
disturbed. Even when placed on fairly damp soil and in an area where 8 hours
of light per day is directed on the solar still, the average yield is only
about 1 cup per day per still. Due to the low yields obtained from this
device, survivors must give consideration to the possible danger of excessive
dehydration brought about by constructing the solar still. In certain
circumstances, solar still returns, even over 2- or 3-day periods, will not
equal the amount of body fluid lost in construction and will actually hasten
(4) Steps survivors should follow when constructing a solar still are: Dig
a bowl-shaped hole in the soil about 40 inches in diameter and 20 inches deep.
Add a smaller, deeper sump in the center bottom of the hole to accommodate the
container. If polluted waters are to be purified, a small trough can be dug
around the side of the hole about halfway down from the top. The trough
ensures that the soil wetted by the polluted water will be exposed to the
sunlight and at the same time that the polluted water is prevented from
running into the container. If plant material is used, line the sides of the
hole with pieces of plant or its fleshy stems and leaves. Place the plastic
over the hole and put soil on the edges to hold it in place. Place a rock no
larger than a plum in the center of the plastic until it is about 15 inches
below ground level. The plastic will now have the shape of a cone. Put more
soil on the plastic around the rim of the hole to hold the cone securely in
place and to prevent water-vapor loss. Straighten the plastic to form a neat
cone with an angle of about 30 degrees so the water drops will run down and
fall into the container. It takes about 1 hour for the air to become saturated
and start condensing on the underside of the plastic cone.
e. The vegetation bag is a simpler method of water procurement. This method
involves cutting foliage from trees or herbaceous plants, sealing it in a large
clear plastic bag, and allowing the heat of the Sun to extract the fluids
contained within. A large, heavy-duty clear plastic bag should be used. The bag
should be filled with about 1 cubic yard of foliage, sealed, and exposed to the
Sun. The average yield for one bag tested was 320 ml/bag 5-hour day. This method
is simple to set up. The vegetation bag method of water procurement does have
one primary drawback. The water produced is normally bitter to taste, caused by
biological breakdown of the leaves as they lay in the water produced and
superheated in the moist "hothouse" environment. This method can be
readily used in a survival situation, but before the water produced by certain
vegetation is consumed, it should undergo the taste test. This is to guard
against ingestion of cyanide-producing substances and other harmful toxins, such
as plant alkaloids. (See Figure 19-12.)
f. One more method of water procurement is the water transpiration bag, a
method that is simple to use and has great potential for enhancing survival.
This method is the vegetation bag process taken one step further. A large
plastic bag is placed over a living limb of a medium-size tree or large shrub.
The bag opening is sealed at the branch, and the limb is then tied down to allow
collected water to flow to the corner of the bag. For a diagram of the water
transpiration method, see Figure
(1) The amount of water yielded by this method will depend on the species
of trees and shrubs available. During one test of this method, a transpiration
bag produced approximately a gallon per day for 3 days with a plastic bag on
the same limb, and with no major deterioration of the branch. Other branches
yielded the same amount. Transpired water has a variety of tastes depending on
whether or not the vegetation species is allowed to contact the water.
(2) The effort expended in setting up water transpiration collectors is
minimal. It takes about 5 minutes' work and requires no special skills once
the method has been described or demonstrated. Collecting the water in a
survival situation would necessitate survivors dismantling the plastic bag at
the end of the day, draining the contents and setting it up again the
following day. The same branch may be reused (in some cases with almost
similar yields); however, as a general rule, when vegetation abounds, a new
branch should be used each day.
(3) Without a doubt, the water transpiration bag method surpasses other
methods (solar stills, vegetation bag, cutting roots, barrel cactus) in yield,
ease of assembly, and in most cases, taste. The benefits of having a simple
plastic bag can't be over-emphasized. As a water procurer, in dry, semi-dry,
or desert environments where low woodlands predominate, it can be used as a
water transpirator; in scrubland, steppes, or treeless plains, as a vegetation
bag; in sandy areas without vegetation, it can be cut up and improvised into
solar stills. Up to three large, heavy-duty bags may be needed to sustain one
survivor in certain situations.
19-8. Preparation of
Water for Consumption:
a. The following are ways survivors can possibly determine the presence of
harmful agents in the water:
(1) Strong odors, foam, or bubbles in the water.
(2) Discoloration or turbid (muddy with sediment).
(3) Water from lakes found in desert areas are sometimes salty because they
have been without an outlet for extended periods of time. Magnesium or alkali
salts may produce a laxative effect; if not too strong, it is drinkable.
(4) If the water gags survivors or causes gastric disturbances, drinking
should be discontinued.
(5) The lack of healthy green plants growing around any water source.
b. Because of survivors' potential aversion to water from natural sources, it
should be rendered as potable as possible through filtration. Filtration only
removes the solid particles from water - it does not purify it. One simple and
quick way of filtering is to dig a sediment hole or seepage basin along a water
source and allow the soil to filter the water (Figure
19-14). The seepage hole should be covered while not in use. Another way is
to construct a filter - layers of parachute material stretched across a tripod (Figure
19-15). Charcoal is used to eliminate bad odors and foreign materials from
the water. Activated charcoal (obtained from freshly burned wood is used to
filter the water). If a solid container is available for making a filter, use
layers of fine-to-coarse sand and gravel along with charcoal and grass.
Figure 19-14. Sediment
Figure 19-15. Water
c. Purification of water may be done a variety of ways. The method used will
be dictated by the situation (such as tactical or nontactical).
(1) Boil the water for at least 10 minutes.
(2) To use purification tablets survivors should follow instructions on the
bottle. One tablet per quart of clear water; two tablets if water is cloudy.
Let water stand for 5 minutes (allowing the tablet time to dissolve), then
shake and allow to stand for 15 minutes. Survivors should remember to turn the
canteen over and allow a small amount of water to seep out and cover the neck
part of the canteen. In an evasion situation, water purification tablets
should be used for purifying water. If these are not available, plant sources
or non-stagnant, running water obtained from a location upstream from
habitation should be consumed.
(3) Eight drops of 2 1/2-percent iodine per quart - stir or shake and let
stand for at least 10 minutes.
d. After water is found and purified, survivors may wish to store it for
later consumption. The following make good containers:
(3) Prophylactic inside a sock for protection of bladder.
(4) Segment of bamboo.
(5) Birch bark and pitch canteen.
(6) LPU bladder.
(7) Hood from antiexposure suit.