Environmental Engineering Reference
In-Depth Information
Over the last nine years, we've had 66 percent of average spring
runoff. That runoff is supposed to supply the lake with water. Four
more years of this, and we lose our upper water intake into Lake
Mead; six more years and we break water elevation 1,000 feet. We
have two water intakes in Lake Mead. The lake is full at elevation
1,204 feet. Our oldest intake is at elevation 1,050. Our lower intake,
installed in the mid-1990s, is at elevation 1,000 feet. We are cur-
rently in the process— at a cost of $1 billion—of installing a third
intake that will go under Lake Mead and come back up at eleva-
tion 860 feet in the dead pool [the isolated water that's left when
lake levels drop too low to permit water fl ow out of the lake],
though it will only be operational at 1,000 feet. To put that in per-
spective, at water elevation 1,050, Hoover Dam stops generating
electricity because [water is] not high enough to get into the tur-
bines of the dam. At elevation 1,000, [there is] less than 5 million
acre-feet left in a reservoir that holds 25 million acre-feet, and the
annual draw on Lake Mead is 9.5 million acre-feet.
You can't build your way out of this unless you start thinking
differently, and I think you'll see the panic button and the crisis
button pushed in the Colorado River Basin the minute the fi rst
round of announced water shortages occurs at elevation 1,075.
We're at elevation 1,100 right now, and we fi gure that even
with normal hydrology this year, we'll be down to 1,095. If we
have a bad year, we'll drop even farther.
As of early September 2010, lake levels had dropped to 1,085 feet with the lake at just 37 per-
cent of capacity. Following heavy rains, the level had climbed back to 1,087 by early January
2011, according to data from the U.S. Bureau of Reclamation (http://azgfd.gov/h_f/edits/
lake_levels.shtm; http://www.usbr.gov/lc/region/g4000/hourly/rivops.html).
The theme for the future must be to accommodate change,
whatever that change might be, says Richards. “Some of the things
we're doing now must be different going forward given our water
supply, climate change, and more,” he says. Whether it's the Great
Lakes compact, water law in the western United States, water law
in general, or scientifi cally based water management strategies, it's
“inevitable that we confront those issues.”
