Making Water Safe to Drink

Splish-Splash
You're stranded on a tropical island with no fresh water in sight but an ocean of salt water surrounds you. Oh the
painful irony. Assuming the presence of a few items, however, all is not lost.

You need - Plastic sheeting (preferably transparent), a clear garbage bag would work nicely, a waterproof cup or
jar, and some stones including one with a flat surface to elevate your cup. We're showing you three similar
methods, the first of which will also require an additional container such as a waterproof tray or tupper-ware
larger than the cup/jar. All of the methods described below are variations of an evaporation-still. The premise is
that the saltwater will evaporate as pure water and leave the salt behind. Cross-sections have been provided for
all 3 methods.

Method 1 - Dig a hole with a flat bottom. Fill your tray/container with water from the sea and set it in the bottom
of the hole. Place your flat-topped stone in the center of the tray and set your drinking cup on top of that. Cover
the hole with the plastic sheet. Set rocks or pile sand around the edge to hold the plastic in place (sand or soil
will form a better seal). Directly over the center of the cup, place a single stone on top of the plastic to form a
depression. Make sure the depressed plastic does not touch the rim of the glass. You want the lowest part of the
plastic suspended just over the center of the cup. Now find some shade to relax in and wait. As water
evaporates, it will rise to the plastic and collect. As it begins to accumulate it will flow to the lowest point (the
dip you created). Collecting water will begin to drip directly into your cup. When you have enough or can wait no
longer, tap the rock in the middle of the tarp to force any last drops to fall into your drinking cup. The water in
the cup is pure and clean as salt does not evaporate with the water. Remove the plastic and drink the water from
the cup.

Method 2 - If you do not have a larger tray or container to hold the saltwater you can dispense with this step
and simply pour a lot of saltwater into your hole. Avoid using your drinking cup for this as it will retain some
saltiness and you're going for pure water here. Let the salt water absorb into the sand enough until you can place
your cup on top of your flat-topped stone without the cup floating away in the saltwater. Follow the steps in
method one to cover the hole with the plastic with the center dip in the plastic suspended directly over your cup.
Even if the ground absorbs most or all of the salt water, it will still be moist and evaporation will take place. In
relatively moist environments you can use this method without first pouring water into the ground. The naturally
damp water will release moisture through evaporation. Particularly porous sand will make this the least effective of
the 3 methods but it could still mean the difference between survival and a painful death by dehydration.

Method 3 - If there is an abundance of vegetation available but the ocean is a long hike away, dig the hole as
before and fill it with leaves and plants. Set your cup in the middle of the collected plant material ensuring it will
not tip over. Moisture from the plants will evaporate up to the plastic and flow into your cup as before.

For each of these methods, clear plastic is recommended as it is the ideal medium for creating an emergency
evaporation-still. The transparent material allows sunlight to penetrate and hasten evaporation and let's you see
the results so you know that you've centered the dip in the plastic over your cup and you can tell when there is
enough water in the cup to drink. However, any non-permeable material such as black plastic bags or vinyl rain
gear will also work. The process will simply take substantially longer and yield less potable water. When you're
dying of thirst, though, anything is better than nothing.