Section 11 EO C190.04 – COLLECT DRINKING WATER IN THE FIELD

The human body consists of 75% water. It is required to keep kidneys functioning so they may eliminate wastes, control body temperature, and regulate the nervous system.

Water is essential to life. All living things contain water and depend on it. The average person can survive for approximately three weeks without food but only three days without water. Do not wait until water supplies have completely diminished to find a water source. When faced with a survival situation, conserve water and find a source as soon as possible. The source should be fresh, running water though. However, boiling or the use of chemical purifiers can sterilize water.

When water is lost from the body it must be replaced to maintain health and efficiency. The human body loses two to three litres of water per day, which must be replaced to maintain the water balance. This water replacement occurs by consuming actual water or water that is contained in food.

The human body has no means of storing water like it can with food fats. When the body is deprived of water it becomes dehydrated, which can affect it in very negative ways.

Effects of Water loss:

The following precautions can be taken to keep fluid loss to a minimum:

Rain Water

Set out a container to collect any rain that may fall. The flow from the roof of a shelter can be collected using improvised guttering to channel the rain into containers. Rainwater requires less purification than a standing body of water. Collecting rainwater is also easier than other collection methods.

Stretch a plastic bag / poncho tightly over a wide area, preferably on a slope. Peg down its corners with sticks and collect the rain in a container. A rock may be used to weigh down the centre and better direct the water into the container. When waterproof sheets are unavailable, use birch bark sheet and shape it to channel the water into a container.

Note. From The Complete Wilderness Survival Manual by Hugh McManners, 1994, Toronto, ON: McMillan Canada.

Figure 1  Rain Collector

As the air cools down at night, the water vapour in the air condenses as dew on low-lying ground, and vegetation. This water evaporates rapidly as the sun rises. Many plants, insects and animals depend upon dew to survive. Humans can also make use of this natural water supply. Dew can be collected by soaking a cloth in long wet grass. The best time for collection is at dawn. When the cloth is soaked, wring the water out into a container. If a cloth is unavailable, a spare t-shirt or other piece of clothing may be used.

Note. From The Complete Wilderness Survival Manual by Hugh McManners, 1994, Toronto, ON: McMillan Canada.

Figure 2  Dew Collection

Water from Vegetation

Tie a plastic bag over a healthy, bushy green branch. The water vapour given off by the foliage heats up inside the plastic and condenses to form water inside of the bag. On trees, keep the mouth of the bag at the top with a corner hanging low to collect condensed evaporation.

Note. From The SAS Survival Handbook, by John Wiseman, 1999, London, England: HarperCollins Publishers.

Figure 3  Collecting Condensation

An entire plant can also be used as a water source. Placing a plastic bag over any vegetation collects moisture by evaporation. The moisture condenses on the plastic as it cools. Suspend the bag to an overhead tree branch, or place a wide stick on the inside to prop up the plastic bag. Arrange points for the water to collect.

Note. From The SAS Survival Handbook, by John Wiseman, 1999, London, England: HarperCollins Publishers.

Figure 4  Collecting condensation from plants

There are many different types of vegetation that store water in either their leaves or roots. Some types of vegetation capture rainwater to trap insects for food. Others secrete special fluids that can be tapped and drank by humans in emergencies. Some examples include: pitcher plants, cacti, tree roots and vines.

Note. From The Complete Wilderness Survival Manual by Hugh McManners, 1994, Toronto, ON: McMillan Canada.

Figure 5  Pitcher Plant

Note. From Camping and Wilderness Survival: The Ultimate Outdoors book by Paul Tawrell, 1996, Green Valley, ON: Author

Figure 6  Cactus

Solar Still

Water can be extracted from soil using a solar still. As long as there is a difference in temperature in between two surfaces, air between those surfaces heats up and becomes saturated. The air condenses as droplets on the cooler surface.

To construct a solar still dig a hole about three feet wide and two feet deep. Place a collecting can at the bottom of the hole. Spread a plastic sheet across the hole and hold it in place with rocks. Weigh down the centre of the sheet over the container with a fist-sized rock. As the temperature of the air and soil rise, water vapour condenses on the underside of the cooler sheet and runs into the container. Dig another hole when the moisture in the hole / still has been used up.

Note. From The Complete Wilderness Survival Manual by Hugh McManners, 1994, Toronto, ON: McMillan Canada.

Figure 7  Solar Still

Digging for Ground Water

Water often seeps into a hole dug in a location where the water table is high. Dig a hole about one foot deep. Water seeps from the ground into the hole. The water is dirty the first few times the hole fills, but clear water eventually rises and can be purified and drunk. Keep scooping away the muddy water until clear water rises. Note the surroundings before a water hole has been dug. Never dig where the mud has a potent smell or a green slime on the surface. This water is probably contaminated. Do not collect water where there are dead animals and always purify the water before drinking.

The objective of this activity is to have the cadets make a water collection device.

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