"If there is magic in this planet" wrote the American Naturalist, Loren Eiseley, "it is contained in water". I love Eiseley. If you have not read this author yet, make a point to do so. This line has always stuck with me. Water nourishes us and makes life possible in so many ways. Not only do we need it to live, but we use it for quality of life as well. Our world is 3/4 water and less than 3% is fresh. Yet all land life on earth literally depends on that small fraction. Eighty percent of that small fraction that is fresh water is now tied up in Ice Sheets (though for how long is anybodies guess) Much of the rest of what is left is contained in ground water. That leaves less than about 0.15 % available in lakes, river and streams . Only a small fraction of this is actually contained in the atmosphere at any one time, to fall out as these beautiful snow flakes that are right now outside my window. That part of the cycle last from only a few hours to a few weeks at most. Compare that to to a drop in a lake which can be contained as such for decades to several centuries. Ocean water can be much longer still and water locked up in the ice sheets can be there for millennium. (It is a sobering thought indeed to consider that when the earth was first being formed, literally all the water on earth was contained in the atmosphere, the environment being simply too hot for liquid water to form for any length of time - imagine the weather forecast around the time the earth became cool enough to form rain)If you're having a hard time imagining these numbers try this little experiment. I use to do this with high school students in the lab. First, fill a one liter container with water. (That is 1000 ml if your metrically challenged.) Now poor just 25ml (2.5 %) of that into a 100 ml glass. Put some salt into the left over liter of water to symbolize the un-potable ocean water that makes up most of the water on earth. Now take just 6ml of the 25ml of water out to another small container to represent the water that is not frozen in glaciers. Poor the left over 19 ml into an ice tray to represent it's real earth storage. Of the remaining6 mls of water (about 0.6 % of the total) about 4.5 ml of this represents ground water. The last 1.5 mls (about one drop from an eye dropper) represents all the fresh water that now exists as surface water in rivers, lakes and such, inlcuding our Great Lakes.It is rather humbling notion to consider while paddling in what seems to be an endless supply of the stuff and more humbling still when we consider what it takes to make this remaining stuff "safe" to drink now. Treat it as the rare element it is and paddle and camp with care.