June 20, 2012 | News
Lake Mead sinks to a new historic low
If lake falls 8 more feet, thirsty Ariz. could experience water restrictions
89 comments by Shaun McKinnon - Oct. 19, 2010 12:00 AM
The Arizona Republic
Lake Mead sank to its lowest level in nearly 75 years on Sunday, a stark reminder of how drought and growing water demands have sapped the Colorado River and its huge reservoirs.
Not since it was first filling in 1937 has Lake Mead held so little water. The reservoir's level fell to the historic low shortly before noon on Sunday, eclipsing a previous record from the drought-stricken 1950s.
The lake is now just 8 feet above the level that would trigger the first drought restrictions, which would reduce water supplies for Arizona and Nevada. That gap could close by next year - the reservoir fell 10 feet from October 2009 to 2010 - but there are measures in place that would likely delay rationing for one or two years or even longer if a wet winter increased runoff into the river.
Most homes and businesses in Arizona likely would not feel the direct effects of the restrictions, which would divert water first from farmers.
But conservation groups say the reservoir's low levels underscore the risk to the Colorado River.
"Everyone needs to know when we turn on the tap, it drains water out of the river and it has ecological consequences," said Gary Wockner, campaign coordinator for Save the Colorado, a non-profit education group based in Fort Collins, Colo. "We need to try to keep some water in the river and keep it alive."
Lake Mead, created when Hoover Dam was built, has shrunk steadily over the past decade, in part because of an unrelenting drought that began to reduce the flow of the Colorado in 2000. The reservoir stores water from the river on behalf of Arizona, Nevada, California and Mexico.
The three lower-river states, along with Colorado, New Mexico, Utah and Wyoming on the upper river, approved a drought plan in 2007 that uses Lake Mead water levels to trigger incremental rationing, part of an attempt to avoid widespread shortages.
The first trigger is at 1,075 feet above sea level. The reservoir reached elevation 1,083.18 feet around midday Sunday and was at 1,083 feet by Monday afternoon. The previous low level was 1,083.19 feet, set in 1956.
The reservoir was last this low as it was filling for the first time, after the dam blocked the river's flow and water began accumulating upstream.
Under the 2007 plan, the first trigger would reduce water deliveries to Arizona by a little more than 11 percent, or 320,000 acre-feet, and to Nevada by about 4 percent, or 13,000 acre-feet. Additional reductions would occur if the lake continued to drop.
An acre-foot is 325,851 gallons, enough to serve two families for one year.
All Arizona's losses would be deducted from the Central Arizona Project allocation, which serves Phoenix and Tucson. Arizona absorbs most of the losses in a drought because water rights in the CAP Canal have a lower priority than most other rights on the lower Colorado River.
The 2007 drought plan included measures that would delay rationing by shifting water from Lake Powell downstream into Lake Mead, raising water levels above the drought triggers.
Lake Mead sinks to a new historic low
If lake falls 8 more feet, thirsty Ariz. could experience water restrictions
89 comments by Shaun McKinnon - Oct. 19, 2010 12:00 AM
The Arizona Republic
Lake Mead sank to its lowest level in nearly 75 years on Sunday, a stark reminder of how drought and growing water demands have sapped the Colorado River and its huge reservoirs.
Not since it was first filling in 1937 has Lake Mead held so little water. The reservoir's level fell to the historic low shortly before noon on Sunday, eclipsing a previous record from the drought-stricken 1950s.
The lake is now just 8 feet above the level that would trigger the first drought restrictions, which would reduce water supplies for Arizona and Nevada. That gap could close by next year - the reservoir fell 10 feet from October 2009 to 2010 - but there are measures in place that would likely delay rationing for one or two years or even longer if a wet winter increased runoff into the river.
Most homes and businesses in Arizona likely would not feel the direct effects of the restrictions, which would divert water first from farmers.
But conservation groups say the reservoir's low levels underscore the risk to the Colorado River.
"Everyone needs to know when we turn on the tap, it drains water out of the river and it has ecological consequences," said Gary Wockner, campaign coordinator for Save the Colorado, a non-profit education group based in Fort Collins, Colo. "We need to try to keep some water in the river and keep it alive."
Lake Mead, created when Hoover Dam was built, has shrunk steadily over the past decade, in part because of an unrelenting drought that began to reduce the flow of the Colorado in 2000. The reservoir stores water from the river on behalf of Arizona, Nevada, California and Mexico.
The three lower-river states, along with Colorado, New Mexico, Utah and Wyoming on the upper river, approved a drought plan in 2007 that uses Lake Mead water levels to trigger incremental rationing, part of an attempt to avoid widespread shortages.
The first trigger is at 1,075 feet above sea level. The reservoir reached elevation 1,083.18 feet around midday Sunday and was at 1,083 feet by Monday afternoon. The previous low level was 1,083.19 feet, set in 1956.
The reservoir was last this low as it was filling for the first time, after the dam blocked the river's flow and water began accumulating upstream.
Under the 2007 plan, the first trigger would reduce water deliveries to Arizona by a little more than 11 percent, or 320,000 acre-feet, and to Nevada by about 4 percent, or 13,000 acre-feet. Additional reductions would occur if the lake continued to drop.
An acre-foot is 325,851 gallons, enough to serve two families for one year.
All Arizona's losses would be deducted from the Central Arizona Project allocation, which serves Phoenix and Tucson. Arizona absorbs most of the losses in a drought because water rights in the CAP Canal have a lower priority than most other rights on the lower Colorado River.
The 2007 drought plan included measures that would delay rationing by shifting water from Lake Powell downstream into Lake Mead, raising water levels above the drought triggers.
