Colorado River Water Storage Without Glen Canyon Dam
Misunderstanding surrounding Glen Canyon Dam's water storage
capability and Colorado River water waste are the major factors
delaying Grand Canyon's restoration. Although the reservoir behind
Glen Canyon Dam, Lake Powell, is part of the present Colorado River
plumbing system that distributes water into seven states and Mexico,
its absence will not cause faucets to run dry.
Each year, Lake Powell loses up to one million acre-feet of water due
to evaporation into the dry desert air, and seepage into the
reservoir's porous sandstone bank-two times Las Vegas' annual water
consumption. Every drop remaining in the Colorado River currently
gets used. The river no longer reaches the ocean, thus recovering
this wasted water would be incredibly valuable to people and
Increasingly, water managers in the Colorado River basin are turning
to storing water in underground aquifers, minimizing evaporative
losses. Implemented on a wider scale, such approaches offer storage
opportunities not explored when Glen Canyon Dam was built.
The Colorado River basin is the most developed river system in the
world, with more than 40 major dams and reservoirs. However, the
water storage value of reservoirs follows a law of diminishing
returns: the more storage reservoirs constructed in a basin, the more
water lost daily due to evaporation. Even before Glen Canyon Dam was
completed, it was recognized that the benefits of its storage
capacity would be largely offset by evaporative losses. Twenty
percent of the Colorado River's annual flow is now lost to
evaporation and seepage from its reservoir system.
After evaporation and seepage, nearly all the water left in Lake
Powell flows downstream to the reservoir behind Hoover Dam, Lake
Mead. Thus, Lake Powell is not needed to service major water users.
Government models reveal that in average years water users below Glen
Canyon and Hoover dams would experience no decrease in water
availability without Glen Canyon Dam, largely because Lake Powell's
significant evaporation and seepage losses would be eliminated.
With or without Glen Canyon Dam, the Colorado River water system is
in collapse. More water is allocated on paper than the river has
historically delivered. The problem is not a lack of water, but a
lack of responsible water use.
Forty percent of Colorado River water is wasted on alfalfa and other
forms of cattle feed requiring up to four times the amount of water
necessary to grow food directly for human consumption. Meanwhile,
residential consumers in the region pour half their water onto
non-native landscaping unsuitable for the region's temperate and
Eliminating such waste would pave the way for restoration well beyond
Grand Canyon, allowing the decommissioning of other unnecessary dams
in the Colorado River watershed.