Trail Sense

Android User Guide Book DEM GitHub

4 - Water

You can only survive a few days without water in most cases, and sometimes not even that long. Knowing how to find and purify water is vital in a survival situation.

This chapter is for informational purposes only and does not replace professional advice; use at your own risk and ensure compliance with local laws.

Be prepared

Gear

Necessities:

Optional:

Knowledge and skills

Start by learning how to do the following:

Once you have mastered these skills, you should learn how to do the following:

Hydration essentials

Assume all surface water is contaminated and requires purification, and if you have to choose a water source, try to find running water. To avoid getting sick or becoming dehydrated quickly, avoid drinking alcohol, saltwater, stagnant water, urine, or eating snow.

At 70°F (20°C), you will need around 2 to 3 quarts/liters of water daily. This amount increases with physical activity and exposure to higher temperatures.

Dehydration

Dehydration occurs when the body loses more fluids than it takes in. Symptoms include thirst, dry mouth and throat, fatigue, dizziness, dark urine, reduced urine output, dry skin, headache, and confusion.

Finding water

You can find water in many places if you know where to look. Unless otherwise stated, you should purify all water that you collect.

Precipitation

Rainwater collected directly in containers does not need purification, but it should be purified if it has touched another surface. Snow and ice should be melted using a fire or body heat before drinking; eating it directly can lower your core body temperature.

Bodies of water

Flowing water from rivers or streams is typically safer than lakes, ponds, and stagnant water. Saltwater can be put into a solar still to remove the salt and should never be consumed directly.

Groundwater

Water is available in many places by just digging a hole in the ground and allowing water to seep in. You can find groundwater in dry environments by looking for green vegetation, valleys, low areas, or dry riverbeds.

Plants

Plants can provide water when no open sources are available. Look for green bamboo, vines, or coconuts for easy access to water, but be sure to positively identify the plant before consuming. You can extract water from other plants by placing them into a solar still.

Dew can be collected from plants in the early morning using a cloth to soak up the water. Only collect dew from plants you can positively identify as safe.

Solar stills

Solar stills produce small amounts of water and are best used as a supplement.

Below-ground solar still

A below-ground solar still is a simple device that uses the sun's heat to draw moisture from the soil or plants. The moisture then condenses on a plastic sheet and can be collected in a container.

  1. Dig a bowl-shaped hole about 3 feet (1 meter) across and 2 feet (0.6 meters) deep. Ensure it is in direct sunlight.
  2. Place a container in the center of the hole. Optionally, place plants or water around the container to increase moisture (do not place them in the container).
  3. Place a plastic sheet over the hole, securing the edges with rocks or soil. You can use a clear bag if you don't have a sheet.
  4. Place a small rock in the center of the sheet directly over the container.
  5. Wait for the sun to heat the ground and evaporate moisture, which will condense on the plastic and drip into the container.

Transpiration bag

A transpiration bag is a plastic bag tied around a leafy branch to collect water. Use multiple bags to increase yield.

  1. Tie a plastic bag around a leafy branch, ensuring that the bag is airtight.
  2. Wait for the sun to heat the plant, causing moisture to evaporate and condense on the bag.
  3. Collect the water that has condensed inside the bag.

Making water safe to drink

Always ensure the water you collect is safe to drink. Boiling is the most reliable method, but chemical purification tablets and filters are also effective. If you cannot purify the water immediately, prioritize finding and storing water until you can treat it.

Boiling

Bring water to a rolling boil for at least one minute. At higher altitudes (above 6,500 ft / 2,000 m), boil for three minutes. If you do not have a single-walled metal container that can be used for boiling, then do the following:

  1. Find another container, dig a hole in the ground and line it with a waterproof material, or craft a bowl.
  2. Fill the container with water.
  3. Heat rocks in a fire and place them in the water to heat it. Do not use rocks that may contain moisture (such as river rocks), as they can explode. Use two sticks in a chopstick fashion to move the rocks.
  4. Replace the rocks with hot ones to keep the water boiling.

Filtration

Use a portable water filter to remove contaminants. Some filters are rated to remove nearly all bacteria and viruses and can be used without additional purification. Custom-crafted filters are less effective and require additional purification.

A filter will have an inlet and an outlet, and it typically shows the direction of water flow with an arrow or text (inlet to outlet). Place the inlet into the dirty water and the outlet into a container, then pump to filter the water. If you are using a filter straw, the outlet goes into the water and the inlet into your mouth. Be careful never to let the outlet come into contact with unfiltered water. After filtering, you can remove the inlet from the water and pump a couple of times to push out excess water. With a straw, forcefully blow into it to clear out water.

If the manufacturer's instructions are different, be sure to follow them instead.

Chemical treatment

Chemical water purification tablets or drops can be used to treat water. Be sure to follow the instructions, which are normally printed on the bottle. The most common chemical is iodine, but chlorine-based treatments are also available. Before deciding which to buy, research how effective they are against bacteria and parasites in your region. Treatment amounts and times vary by chemical type and brand. Be sure to check the expiration date (if any) before going on a trip.

If you are pregnant or have thyroid problems, don't use iodine. Always read the warnings on the packages of chemical purification solutions before buying them.

Here are some general steps for iodine tablets if you lost the instructions (based on the most popular brand, Potable Aqua):

  1. Fill up a bottle of water. You may want to run the water through a filter or cloth to remove sediment.
  2. Add 2 tablets per quart/liter of water and put the cap on loosely.
  3. Wait 5 minutes and shake. Be sure some water leaks out the cap and around the threads.
  4. Tighten the cap and wait 30 minutes.
  5. (Optional) Add 2 neutralizer tablets per quart/liter, shake, and wait 3 minutes. This will help to improve the taste.
  6. Your water is now ready to drink.

Conversions

The following conversions are approximate, but that is fine for purification.

Solar disinfection

As a last resort, you can use sunlight to purify water in a clear water bottle.

  1. Fill a clear water bottle with water. If the water is cloudy, run it through a filter or cloth first.
  2. Remove the label from the bottle and lay it on its side in direct sunlight. If you have something dark, place it underneath the bottle to increase effectiveness.
  3. If it is sunny, most germs will be killed in 6 hours. If it is cloudy, you will need to wait 2 days - so consider using a different purification method.

Hazards

Water may contain bacteria, viruses, and parasites that can cause illness. Boiling water kills most microorganisms, but some may require additional treatment. Microorganisms are more likely to be present in stagnant water.

Water may contain chemicals from industrial or agricultural runoff. Purification methods may not remove all chemical contaminants. Avoid drinking water next to roads, farms, or other inhabited areas.

Craft: Bowl

A wooden bowl can be used to boil water using hot rocks.

Resources

Instructions

  1. Cut or obtain a small log.
  2. Place hot coals into the log using makeshift tongs.
  3. Let the coals burn out.
  4. Scrape out the charred wood with a stick or rock.
  5. Repeat the process until you have a bowl.

Craft: Tongs

You can use tongs to move around hot coals or rocks without getting burned.

Resources

Instructions

  1. Cut a length of green wood.
  2. Split the wood down the middle to create a flat surface.
  3. Optionally, carve a small notch in the stick's center to allow it to bend more easily.
  4. Bend the wood in half to create tongs.

Craft: Filter

A crafted filter can be used to remove sediment from water, but it will still require additional purification.

Resources

Instructions

  1. If using a water bottle, cut off the bottom and remove the cap. You will be using the bottle upside down.
  2. Tie a cloth onto the top of the bottle. If you choose not to use a cloth, poke holes in the cap and screw it back on. If using a container like a cup, poke holes in the bottom, then add some grass or rocks to the container.
  3. Add 1 inch (2.5 cm) of crushed charcoal to the container.
  4. Add 1 inch (2.5 cm) of sand to the container.
  5. Add 1 inch (2.5 cm) of gravel or grass to the container.
  6. Repeat steps 3-5 until the materials reach about 2 inches (5 cm) from the top of the container.
  7. Pour water into the filter and collect it in a second container.
  8. Purify the filtered water by boiling or using chemical treatment.