Water is a physical substance with which all persons are familiar. However, if you were to ask people what does water mean to their life, or what is its 'value', you would likely get very different answers. In an area that is water rich, water may be another utility that conveniently comes out of the tap. In a water poor area, water represents day-to-day survival and all activities revolve around water supply and usage. Given such drastic differences in the importance and role of water in society from one location to the next, an understanding of the contribution of geography to sustainable water resource management is imperative.
However, before we delve into the geography of water resources, we must first answer the question: why is water important? The simple answer is that it is a fundamental requirement to life on our planet. All of the Earth's organisms are composed mostly of water. About 60 percent of a tree is water by weight and humans are 50-60 percent water (Miller 1996). Without water, biological organisms would be unable to complete basic physiological processes that sustain life. Moreover, water is an integral part of the Earth's biogeochemical process that creates and sustains our environment. For instance, water cycles through the atmosphere modifying day-to-day weather. Consequently, water is an essential resource for many human activities required to sustain our current society; agriculture, industry, and transportation are just a few of the myriad human activities that require water.
The water used by terrestrial biological organisms and other human activities is freshwater, not the saline water of oceans. Of the total amount of water on the Earth's surface, about 97 percent is saline, contained in the world's oceans, and only 3 percent of the world's water is fresh, with the largest portion of freshwater contained in glaciers (see sketch of this concept). If the world's entire water supply were only 100 liters, our usable supply of fresh water would be only about 0.003 liters, or about one-half a teaspoon (Miller 1996).
Pause and Reflect 1:
Do you consider the region you live in to be "water rich" or "water poor"? Why?
How does this situation influence the ways in which fresh water is obtained and managed in your region?