Water

All materials on this page have been taken directly from
The SAS Survival Guide by: John Wiseman (Harper Collins Pub.)
And are to be used for this educational activity only.


     As you enter the Water Training Facility you see a large rectangular hall with five smaller cubicles sectioned off from one another. In each of these cubicles a computer controlled holographic image provides trainees with the instruction needed to explain the particular method of water collection. It then provides a simulation in which the trainees can test out the method of water collection that has been covered.

     The Lieutenant Commander in charge of Water training welcomes you to the facility and begins his lecture:

     "When in a survival situation, ordering your priorities is one of the first steps to ensuring survival. Our basic needs are:

Their order of importance will depend on where you are and the environmental conditions, but water is always essential.

     It is essential to remember that, an adult can survive for three weeks without food, but only three days without water. Don; wait until you run out of water before you look for more. Conserve supplies and seek a new source of fresh running water, though all water can be sterilized.

     It is also important that you realize that the human body loses 2-3 litres of water each day. Loss of fluids through respiration and perspiration increases with work rate and temperature. So it is important to conserve energy and remain cool. Maintaining good health is also imperative since vomiting and diarrhoea increase water loss further. This water must be replaced either by actual water or water contained in food.

     In order to keep fluid loss to a minimun, you should observe take the following precautions as much as possible:


     She then points you to the five cubicles and says:

In these cubicles you will find a number of ways to obtain water in the wilderness. Listen to the holographic instructions for each method carefully. You can feel free to "re-run" the instructor segment as often as you need. You should try out at least two of the procedures yourself to get a better feel for how they work and how well they work. Remember that while boiling water can kill any organisms that live in it it will not remove harmful minerals or chemicals that may be present in it." She then dismisses you to begin your training.




Finding Water

     Water runs downhill, so look in valley bottoms where water naturally drains. If there is no stream or pool, look for patches of green vegetation and dig there (green plants need a good water supply to survive).

In arid regions, dig in gullies and dry stream beds. In the mountains look for water trapped in drevices. On the coast, dig above the high water line, or look for lush vegetation in faults in the cliffs, you may find a spring.




Collecting Rain, Condensation and Dew

     Nature can also provide you with water in the form of rain, condensation and dew. You can collect this moisture to use as a water source. In the case of rain, use as big a catchment area as possible, running the water off into containers. A covered hole in the ground lined with clay will hold water. If you have no impermeable sheeting, use metal sheets or bark to collect the water.      Dew is the moisture that appears on the grass or plants over night. As the ground cools the water vapour condenses and is deposited on the surface of plants. You can also use cloth to soak up this water. Tie clean strips of around your legs and walk through wet vegetation. These cloths can then be sucked to remove t the water.

     You can also collect the water vapour that is given off by plants as they photosynthesize. Trees can draw moisture from a water table 15 meters or more below the surface. Far too deep for you to dig. So let the tree pump the water for you.

  1. Select a healthy, green, leafy branch that you can reach easily.
  2. Enclose as much of the leafy vegetation on the end of the branch as you can into a plastic bag and tie it closed around the branch.
  3. Water that evaporates from the leaves will condense on the inside of the bag.
  4. Make sure that one corner of the bag hangs lower than the rest of the bag. The water droplets will collect in this corner of the bag.
  5. This is pure water that can be used for drinking.




Solar Still

     In cases where you can not find clean water, or any water at all, you can create a device known as a solar still. This tool works best in areas where it is hot during the day and cool at night. It allows you to collect pure water vapour from the earth or from impure water sources.

  1. Dig a hole approximately 90 cm across and 45 cm deep.
  2. Place a collecting tin in the center of the hole.
  3. Using a stone, roughen the underside of a sheet of plastic to ensure that water droplets will down it.
  4. Cover the hole with this plastic sheet.
  5. Secure the edges of the sheet with stones and be sure that the plastic dips down in the center forming a cone shape.
  6. The sun raises the temperature of the soil and air beneath the plastic cover producing water vapour.
  7. This vapour is trapped by the plastic sheet.
  8. When the sun sets the air begins to cool again and the water runs down off of the plastic sheet into the collecting vessel.
  9. This type of still should produce at least 550 ml of water in a 24 hour period.

A solar still can also be used to distill pure water from poisonous or contaminated liquids. Place a container of impure water inside of the still and the sun's heat will cause the water to evaporate from it. The still then collects the vapor as pure water.

The still can also double as a trap. Insects and small snakes, attracted by the plastic, fall down into the "cone" or slither under the plastic and into the hole from which they are unable to escape.




Return to the Survival Training Center.