Environmental Engineering Reference
In-Depth Information
to flow underneath. Today, the graffiti which had been scribbled on the bridge at that
grade a quarter of a century ago is now more than thirty feet up in the air!
Given such water velocities, it is not just the soil that is lost but also the wetland
plants. Prior to 1985, there were about 2,300 acres of wetlands in the Las Vegas
Wash. By 2000, it was estimated that the total area or riparian habitat plus wet-
lands was only about seven hundred acres (Scharnhorst 2004). And prior to serious
restoration efforts which began a few years later, the remaining wetlands had been
reduced to an area of less than 10 percent of their original extent.
The entire region of the arid southwestern United States has received an enor-
mous population boom that has deleteriously affected its desert ecosystems. So
as has been the case for the Hula Swamp in Israel (chapter 6), the Azraq Oasis in
Jordan (chapter 7), the Palmyra reed fields in Syria, and the southern marshes in Iraq
(France 2007), the Las Vegas Wash is yet another glaring example of the destruction
of that most incongruous and therefore rarest and most precious of all ecosystems:
desert wetlands.
However, the saga of the Las Vegas Wash is also an encouraging story of environ-
mental advocacy. Over time, people came to realize that this was truly an ecosystem
that should be restored not just for its own sake, but also for its substantial educa-
tional and aesthetic values (France 2009). So it was in 1973 that the Las Vegas Wash
Development Committee was formed, and in 1982 Scharnhorst and her colleagues
began working on both the environmental assessment of the Wash as well as the
first generation of a master plan of what would eventually become the Clark County
Wetlands Park (see chapter 13).
PROTECTION EFFORTS
Another devastating storm in 1984 had interesting repercussions with respect to how
people came to view the Wash (Scharnhorst 2004). There is a single water supply
pipeline running from Lake Mead to the Las Vegas valley, and in that single storm
the pipeline was exposed by the removal of over thirty-five feet of overlying sedi-
ment. Until that time, the thinking had been so isolated that the Las Vegas Valley
Water District had stated that “the erosion in the Wash isn't our problem. We've got
the money and the resources and we're going to bury that pipe two hundred feet below
the Wash.” The Regional Flood Control District in turn said that “it's not really our
problem because the pipe is underneath the bottom of the valley and we just really
handle the valley surface.” The Clark County Parks and Recreation Department
(CCPRD) said, “We think there is the potential for a great park, but it doesn't look
like there will be anything left of the park for us to protect and enhance.” And there
were a number of other agency stakeholders who for a number of reasons wouldn't
assume responsibility for the situation. So, after the 1984 flood another integrated
planning study was drafted by another Wash taskforce made up of mostly agency
individuals, and another stop-gap erosion mitigation project was put in place by the
federal government. Finally, in about 1990 the CCPRD decided that they needed to
take ownership of the problem and to really work to move toward restoring the Wash.
Their strategy was to pass a state-wide bond initiative to raise the necessary funds,
which if put before voters before 1990 probably wouldn't have passed because there
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