Mead declines to lowest level in history
nation’s largest reservoir has broken a record, declining to the
lowest level since it was filled in the 1930s.
Mead reached the new all-time low on Wednesday night, slipping below
a previous record set in June 2015.
downward march of the reservoir near Las Vegas reflects enormous
strains on the over-allocated Colorado River. Its flows have
decreased during 16 years of drought, and climate change is adding to
the stresses on the river.
the levels of Lake Mead continue to fall, the odds are increasing for
the federal government to declare a shortage in 2018, a step that
would trigger cutbacks in the amounts flowing from the reservoir to
Arizona and Nevada. With that threshold looming, political pressures
are building for California, Arizona and Nevada to reach an agreement
to share in the cutbacks in order to avert an even more severe
problem is not going away and it is likely to get worse, perhaps far
worse, as climate change unfolds,” said Brad Udall, a senior water
and climate research scientist at Colorado State University.
“Unprecedented high temperatures in the basin are causing the flow
of the river to decline. The good news is that we have time and the
smarts to manage this, if all the states work together.”
said that will require “making intelligent but difficult changes to
how we have managed the river in the past.”
of Thursday afternoon, the lake’s level stood at an elevation of
about 1,074.6 feet. The federal Bureau of Reclamation, which manages
the reservoir and Hoover Dam, projects the level to decline a few
feet more to an elevation of about 1,071 feet by the end of June,
before the level begins to rise again with releases of water from
the federal guidelines that govern reservoir operations, the Interior
Department would declare a shortage if Lake Mead’s level is
projected to be below 1,075 feet as of the start of the following
year. In its most recent projections, the Bureau of Reclamation
calculated the odds of a shortage at 10 percent in 2017, while a
higher likelihood – 59 percent – at the start of 2018.
those estimates will likely change when the bureau releases a new
study in August. Rose Davis, a public affairs officer for the Bureau
of Reclamation, said if that study indicates the lake’s level is
going to be below the threshold as of Dec. 31, a shortage would be
declared for 2017.
would lead to significant cutbacks for Arizona and Nevada.
California, which holds the most privileged rights to water from the
Colorado River, would not face reductions until the reservoir hits a
lower trigger point.
of California, Arizona and Nevada said last month that they hope to
have a deal finalized by the end of the year for all three states to
accept cutbacks earlier than otherwise required in order to head off
a more serious crisis.
Secretary Sally Jewell has said she is optimistic about the talks,
calling the over-allocation of the river a shared problem that must
be solved. During a May 4 visit to Southern California, she said that
there has been “extraordinary collaboration” between the states
in working toward a deal, and that the United States and Mexico have
also been making progress in negotiations on a new accord to share
water from the Colorado River.
representatives of the three states have discussed the outlines of
proposals to temporarily take less water from Lake Mead, they
including negotiations between water districts within each state.
legal framework that divvies up the Colorado River was established
during wetter times, starting with the 1922 Colorado River Compact.
That and subsequent agreements have handed out more water than what
flows in the river in an average year, leading to chronic overuse.
population growth and heavy demand for water collide with hotter
temperatures and reduced snowpack in the future, there will be an
even greater mismatch between supply and demand, said Kelly Sanders,
an assistant professor at the University of Southern California who
specializes in water and energy issues.
question becomes how to resolve this mismatch across states that all
depend on the river to support their economic growth,” Sanders
said. She expects incentives and markets to help ease some of the
strains on water supplies, “but it is going to be tricky to make
the math work in the long term.”
records show that the level of Lake Mead hasn’t been this low since
1937, when the reservoir was being filled.
have estimated that
rising temperatures and the resulting declines in runoff across the
Colorado River Basin could reduce the river’s flow by between 5
percent and 35 percent by the middle of the century.
climate warming will drive larger and larger flow reductions as long
as emissions of greenhouse gases continue,” said Jonathan Overpeck,
co-director of the University of Arizona's Institute of the
river is over-allocated even before climate change is factored in,”
Overpeck said in an email. He said he thinks the negotiations will
probably “focus on how to reduce the over-allocation, but will
eventually have to focus on sharing the pain as climate change
continues to reduce the flows.”
California eases water restrictions, but drought continues
19 May, 2016
California has loosened emergency restrictions on water conservation after El Nino-driven storms boosted reservoir levels this winter in parts of the state, authorities announced.
The State Water Resources Control Board voted unanimously on Wednesday to roll back strict conservation rules and to allow local communities to set their own savings targets based on water supply.
That means that regions that received a lot of rain will see fewer restrictions, while dry regions will still have to abide by strict conservation measures.
"El Nino didn't save us, but this winter gave us some relief," water board chair Felicia Marcus said in a statement. "It's a reprieve though, not a hall pass, for much if not all of California."
Governor Jerry Brown last year ordered a 25 percent cut in water use as the state suffered through the fourth year of an unprecedented drought.
Officials said the emergency measures resulted in 1.3 million acre-feet of water conserved from June 2015 to March of this year.
A wet winter also helped replenish reservoirs in some parts of the state.
The new rules adopted on Wednesday will go into effect June 1 and will run through January 2017.