Other sources of water
A careful inspection of the terrain may indicate some possible sources of subsurface water (Figure 16.1). This is generally found where there are signs of vegetation—the greener the vegetation the better the chances of finding water. The base of a hill is the most likely spot. Small soaks can be found on the shoulders of escarpments/cliffs that are sheltered from the sun and support green growth.
Observe bird movement in the afternoon, as they are a good indicator of the direction of water.
Dry creek beds or water holes often hide water up to 60 cm below the surface. A shallow hole dug at the lowest point on the outside of a bend may produce a seepage of water into the hole.
When roots of trees or scrub and leaves are placed in a plastic bag they will lose water through transpiration, and the subsequent condensation can produce drinkable water.
Two plants common in desert regions following substantial rain are parakeelya (Calandrinia sp.) and portulaca (pigweed). Parakeelya are small succulent plants mostly with pink flowers and short stems. Both are edible and will allay thirst if chewed, as the leaves contain a large percentage of water.
Trapping water from live vegetation
In hot conditions, it can be possible to capture up to about 300 ml of water per 24 hour period by enclosing in a large garbage bag bunches of foliage attached to living branches of trees. The bags should be attached carefully and any puncture holes sealed with tape and the bag sealed as tightly as possible around the branch. Aim to enclose as much vegetation as possible. Experience has shown that generally the young, actively growing parts of eucalypts and introduced European trees work best, followed by conifers and heathy bushes, etc. Bags should be attached early in the morning, and placed in positions where the branch will be in as much direct sun during the day as possible. The main disadvantage of this technique is that in certain circumstances it can kill the branches of the trees used. It is worth reserving this method for emergencies.
Solar water still
Extensive experience with solar stills in arid conditions suggests that they are generally ineffective in producing any useful quantity of water. As they produce much less water than the method of attaching bags to trees, and probably cause more environmental damage, it is hard to recommend devoting the time and effort required to build one.