Environmental Engineering Reference
In-Depth Information
the standard language of aviation, among foreign cockpit crews add
to the risks.
The quality of runways at many commercial airports in the United
States is unsatisfactory. In 2003, the FAA rated 80 percent of the runways
as good, 18 percent as fair, and 2 percent as poor. New runways can
increase an airport's capacity by as much as 30 to 60 percent. The
median time to open a new runway is ten years.
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Maintaining the integrity of the national airport system requires con-
tinual updates and a steady and predictable fl ow of capital. Airport
funding comes from several sources:
Airport bonds, 59 percent
Federal grants, 21 percent
Passenger facility charge, 13 percent
State and local funding, 4 percent
Airport revenue, 4 percent
The FAA has estimated that planned capital improvement of $9 billion
annually is needed to meet expanding demand. The Airport Council
International estimates $15 billion. Congress in 2003 authorized $14.2
billion for the Airport Improvement Program for the years 2004-2007,
which amounts to only $3.55 billion per year.
When the Levees Break
The large fl oods in recent years along the Mississippi River and its
tributaries have focused public attention on the nation's artifi cial levee
system—the constructed embankments along rivers designed to hold
fl ooding rivers within their channels. The federal government has advo-
cated and supported their construction for more than a century, although
85 percent of the nation's estimated 100,000 miles of levees are locally
owned and maintained. Many are over fi fty years old. Over the years,
the U.S. Army Corps of Engineers has built levees along the Mississippi
River and its tributaries that total 7,000 miles in length. Some of these
levees are 30 feet high.
In 2007 the Corps of Engineers reported that 122 levees around the
country could fail in a major fl ood; 37 are in California and 19 in Wash-
ington State.
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The dangerous levees were designed poorly and built of
whatever material was close by, such as clay, soft soil, and sand mixed
with seashells. These unsuitable and structurally weak materials have
been weakened still more over time by tree roots, shifting stones and
