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The newspaper headlines said it all. water, a substance most people take for granted, was creating problems all over the country. In some places there was too little water' in other places too much. A severe drought in the West had left hundreds of square kilometers of forest dry. Forest fires raged in these areas, causing heavy damage. Firefighters battled in vain to stem the fire's destructive path. Meanwhile, heavy rains in some southern states had flooded rivers, lakes, and streams. Dams could no longer hold the huge quantities of water building up behind them. In several places, dams collapsed. Water and thick streams of mud buried land and homes under a heavy sheet of wet, brown dirt. Perhaps you have never thought of water as the cause of such problems. To you, water is a natural resource you use every day to stay alive. In fact, more than 500 billion liters of water are used every day in the United States alone. Within the next 20 years, this staggering volume will probably double! Where does our supply of fresh water come from? Will there always be enough? In this chapter you will learn about the Earth's supply of fresh water, as well as the answers to these questions. |
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When you look at a photograph of Planet Earth taken from space, you can observe that water is one of the most abundant substances on Earth's surface. In fact, astronauts-whose views of Earth differ from those of most people-have described the Earth as the blue planet! A casual glance at a world map might make you think that the Earth has an unending supply of fresh water-a supply that can meet the needs of living things forever. After all, the oceans cover more than 70 percent of the Earth's surface. Actually, about 97 percent of all the water on Earth is found in the oceans. |
As you can see, only a very small portion
of the Earth's water is available for use by the population of
the planet
