Water Sourcing

Drinking to stay hydrated is just something that we do automatically without thinking and the importance of water to the human body is often overlooked.  We are all taught that we are made up of 70% water which in the average adult is approximately 40 litres. 

Every day we lose about 1.5 litres through respiration, sweating and in our faeces with a similar amount excreted as urine.  So we need to replace this loss by consuming about 3-4 litres a day in food and drink.  This is in temperate temperatures with an average amount of exercise. At higher temperatures and/or through strenuous exercise the amount lost through sweating and through respiration can increase exponentially.

Just a 5% loss of body fluid will affect performance; stamina, manual dexterity, mental capacity etc. A 10% loss will result in hallucinations and death can occur with just 20% dehydration.  In cooler climates humans can survive up to 5 days or so without water. In temperatures above 400C this can be reduced to just 24 hours.

In this country finding water is not normally too difficult, but in some areas, with permeable underlying rock such as chalk and limestone, ground water can be some distance away.   Normally where the water hits a more impermeable layer such as clay will it resurface above the ground.

If there is no actual standing ground water sometimes a Gypsy or Indian well can be dug in damp areas.  This will collect water from the surrounding saturated soil and in the right conditions can provide a reliable long term water supply.

Don’t forget less obvious water sources such as rain water, which can be collected as run off from a tarp or by lining a pit with a plastic bag, or even early morning dew which can be collected by tying clothing or towels around your lower legs early in the morning.

In arid parts of the world surface water may be seasonal or virtually non-existent and it becomes more of a challenge to locate it.

We can use indicator species of animals and plants to help us locate water.  Obvious examples are things like ducks and waterfowl, wading birds, dragon flies, reeds, willows etc., but there are also the less obvious.  Pigeons, game birds and some finches have a very dry diet and need to drink regularly, wasps and bees are never too far from water, wild horses and wild pigs also need to drink daily so don’t stray far away from a water source.  The tracks of several animal species converging in one direction, often points to a water hole.

In the deserts of North Africa and the Middle East the Date Palm is a good sign, as although it can grow in extreme temperatures, it still needs large amounts of water at its roots.

Look at the geology. Water always runs downhill, so head in that direction.  Look at areas where a porous rock overlies a non-porous type.

Dried up river beds may harbour water in the sand on the outer bends of the river but it could be several feet down.  Coastal sand dunes may yield fresh water floating on top of the brackish water by digging down in the dips between the dunes.  In large boulder fields water can collect in gaps between the rocks and remain for some time.

Water can be sources from plants.  In temperate regions some trees like Silver Birch and some of the Maples can yield reasonable quantities of sap at certain times of year.  Some species of cactus in the Americas can be mashed up to get liquid, as can some melon like fruits in the Kalahari.  In jungle regions vines and lianas as well as banana plants can also provide a drink if prepared correctly.

In a marine environment the eyes of large fish have been utilised by people lost at sea to provide a fresh water source.

There are some survival techniques that are often described in books but which in practice are often not worth attempting.  The best known of these is the solar still.  A large hole is dug into which vegetation, urine or other moisture containing items are placed before being covered with a large clear plastic sheet.  A cup or collecting device is placed in the bottom if the hole and the plastic sheet is weighted down and sealed around the edges.  A stone is placed in the middle of the sheet to create a small depression above the collecting container.  The theory is that the sun will evaporate the moisture contained inside the pit which will condense on the inside of the plastic sheet. The droplets will collect and run down to the lowest point where they drip into the collecting device.  In reality unless this is carried out on a beach in sand saturated by sea water you are likely to lose more in sweat building the still than you will ever collect in it.

The only one of these survival techniques which is effective is called the transpiration bag whereby you place a large, clear plastic bag over the leafy branches of a tree or shrub and tie the neck of the bag tightly around the branches.  Place a stone in one corner to weigh it down. The sun light causes moisture to evaporate from the leaves, condense on the inside of the bag and collect in the weighed down corner.  Even with desert plants which are designed conserve as much water as possible this method is reasonably effective.

However you source your water, always remember that the World Health Organisation recommends that all wild water is potentially contaminated and should be filtered and purified.

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