Environmental Engineering Reference
In-Depth Information
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CHAPTER
LIQUID GOLD
We have really no idea how bad off we are. It's a disaster waiting to
happen.
—
Daniel E. Williams,
Sustainable
Design: Ecology,
Architecture, and Planning
W
ater is Earth's most abundant resource—70 percent of
Earth's surface is water—yet less than 1 percent is the readily
accessible freshwater we human beings must have to survive.
That's not much to meet the needs of the world's nearly 6.9
billion people, about 310 million of them in the United States.
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Water was once without question a renewable resource, but that's
not necessarily the case today. We've overused it, polluted it,
drained it, and built up and over Earth's natural means to replen-
ish it, especially when drought and changing climate are part of
the equation. Even our approach to development has encroached
on our ability to replenish our most needed, if not most valuable,
resource. Parking lots, streets, and walkways pave out the water
by interfering with the planet's natural ability to restock its
freshwater supplies.
Where does Earth's water come from? Figure 1.1 illustrates the
breakdown of Earth's water supplies.
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