Despite our common perception, in our surroundings there is often more water than we usually think; this is an important fact for survival but also something that should be well understood as part of our personal environmentalism.
In many survival manuals you will find different methods for finding and collecting water. Surely, having a nice stream of clear, fresh mineral water is always better but such pleasures do not come by often in places like a desert or a town. So, to get some water from your own garden soil if there is a major electrical blackout and water pumps cease to work, or if you are in some sort of arid land you would need to do something else. Digging comes to mind first, but alas, the best way to get that water that you need requires little labour: You can leave nature to do the job for you. Indeed, plants are extraordinary water pumps and their daily work produces no contamination, requires no electrical connections and makes no perceivable noises. Had our society evolved technologies related to pumping water by means of plants instead of hydraulic mechanisms of the sort that we have, our global energy requirements as well as contamination would be significantly lower.
Unfortunately, we will not always enjoy such a water source.
From a fairly significant extension of even arid land, big quantities of water could be obtained; this leads to the concept of hydraulic farms that could be established in regions where conventional agriculture for food production is not practical or profitable. Such installations would have very low energy requirements in the conventional sense, and their environmental impact could be insignificant or non-existent, provided that they are well designed.
Plants get water from the soil by capillary means; the internal anatomy of even the simplest plant is so complicated that we still have no real clues as to how photosynthesis works, but we do know that plants are among the most successful pumping devices all around: A big tree slurps an amount of water each second that is similar to what goes thorough a fireman's hose. The potential for fetching water by means of plants is enormous: For survival purposes, several people have developed interesting methods that albeit slow, work flawlessly and may serve as the basis for the develop of some sort of hydraulic gardens destined for providing some serious quantities of the essence of life on our planet. Think about how much could you save on bills and environmental consequences by having just your washing machine receive water from a single tree.
This video shows one of the simplest survival methods for gathering water from plants, but the same principle might be used in some sort of hydraulic farm to pump water in more significant quantities.