“If these projections materialize, we’re very quickly going to lose control of how to manage the deteriorating conditions on the #ColoradoRiver” — John Entsminger #COriver #drought

Lake Mead bathtub ring Mark Henle Arizona Republic

From The Associated Press (Dan Elliott):

A vital reservoir on the Colorado River will be able to meet the demands of Mexico and the U.S. Southwest for the next 13 months, but a looming shortage could trigger cutbacks as soon as the end of 2019, officials said Wednesday.

A forecast from the U.S. Bureau of Reclamation echoes previous warnings that a nearly 20-year trend toward a drier regional climate coupled with rising demand could drain so much water from the Lake Mead reservoir that cutbacks would be mandatory.

The report increases the pressure on seven U.S. states that rely on the river to finish a long-delayed contingency plan for a shortage.

“If these projections materialize, we’re very quickly going to lose control of how to manage the deteriorating conditions on the Colorado River,” said John Entsminger, general manager of the Southern Nevada Water Authority, which serves 2.1 million people, including the city of Las Vegas.

The Colorado River system — including the giant Lake Mead and Lake Powell reservoirs — serves about 40 million people and 6,300 square miles (16,300 square kilometers) of farmland. Arizona, California, Colorado, Nevada, New Mexico, Utah and Wyoming rely on the river, along with native American reservations and northwestern Mexico…

The Bureau of Reclamation forecast says all the users will get their usual share through September 2019. But the report projects that by October 2019, the surface of Lake Mead could fall below 1,075 feet (330 meters) above sea level, the agreed-upon point that would trigger an announcement of cutbacks that would occur sometime in the following 12 months…

The chances of a shortage in late 2019 remain at 52 percent, the same odds the bureau announced in May, he said. Lake Mead has never had a shortage and if next winter provides enough snow in the mountains that feed the river, it could be averted, Duke said.

Here’s the latest report from the Bureau of Reclamation:

The operation of Lake Powell and Lake Mead in this August 2018 24-Month Study is pursuant to the December 2007 Record of Decision on Colorado River Interim Guidelines for Lower Basin Shortages and the Coordinated Operations of Lake Powell and Lake Mead (Interim Guidelines), and reflects the 2018 Annual Operating Plan (AOP). Pursuant to the Interim Guidelines, the August 2017 24-Month Study projections of the January 1, 2018, system storage and reservoir water surface elevations set the operational tier for the coordinated operation of Lake Powell and Lake Mead during 2018.

Consistent with Section 6.B of the Interim Guidelines, the Lake Powell operational tier for water year 2018 is the Upper Elevation Balancing Tier. With an 8.23 million acre-feet (maf) release from Lake Powell in water year 2018, the April 2018 24-Month Study projected the end of water year elevation at Lake Powell to be above 3,575 feet and the end of water year elevation at Lake Mead to be below 1,075 feet. Therefore, in accordance with Section 6.B.4 of the Interim Guidelines, Lake Powell operations shifted to balancing releases for the remainder of water year 2018. Under Section 6.B.4, the contents of Lake Powell and Lake Mead will be balanced by the end of the water year, but not more than 9.0 maf and not less than 8.23 maf shall be released from Lake Powell. Based on the most probable inflow forecast, this August 24-Month Study projects a balancing release of 9.0 maf in water year 2018.

Consistent with Section 2.B.5 of the Interim Guidelines, the Intentionally Created Surplus (ICS) Surplus Condition is the criterion governing the operation of Lake Mead for calendar year 2018.

The August 2018 24-Month Study projects the January 1, 2019 Lake Powell elevation to be below the 2019 Equalization Elevation of 3,655 feet and above elevation 3,575 feet. Consistent with Section 6.B of the Interim Guidelines, Lake Powell’s operations in water year 2019 will be governed by the Upper Elevation Balancing Tier, with an initial water year release volume of 8.23 maf and the potential for an April adjustment to equalization or balancing releases in April 2019. Consistent with Section 6.B.4 of the Interim Guidelines, an April adjustment to balancing releases is currently projected to occur and Lake Powell is projected to release 9.0 maf in water year 2019.

The August 2018 24-Month Study projects the January 1, 2019 Lake Mead elevation to be above 1,075 feet. Consistent with Section 2.B.5 of the Interim Guidelines, the Intentionally Created Surplus (ICS) Surplus Condition is the criterion governing the operation of Lake Mead for calendar year 2019.

The 2019 operational tier determinations will be documented in the 2019 AOP, which is currently in development.

The Interim Guidelines are available for download at: https://www.usbr.gov/lc/region/programs/strategies/RecordofDecision.pdf.

The 2018 AOP is available for download at: https://www.usbr.gov/uc/water/rsvrs/ops/aop/AOP18.pdf.

Current runoff projections into Lake Powell are provided by the National Weather Service’s Colorado Basin River Forecast Center and are as follows: Observed unregulated inflow into Lake Powell for the month of July was 0.123 maf or 11 percent of the 30-year average from 1981 to 2010. The forecast for August unregulated inflow into Lake Powell is 0.165 maf or 33 percent of the 30-year average. The preliminary observed 2018 April through July unregulated inflow is 2.602 maf or 36 percent of average.

In this study, the calendar year 2018 diversion for Metropolitan Water District of Southern California (MWD) is forecasted to be 0.941 maf. The calendar year 2018 diversion for the Central Arizona Project (CAP) is forecasted to be 1.466 maf. Consumptive use for Nevada above Hoover (SNWP Use) is forecasted to be 0.277 maf for calendar year 2018.

Due to changing Lake Mead elevations, Hoover’s generator capacity is adjusted based on estimated effective capacity and plant availability. The estimated effective capacity is based on projected Lake Mead elevations. Unit capacity tests will be performed as the lake elevation changes. This study reflects these changes in the projections.

Hoover, Davis, and Parker historical gross energy figures come from PO&M reports provided by the Lower Colorado Region’s Power Management Office, Bureau of Reclamation, Boulder City, Nevada. Questions regarding these historical energy numbers can be directed to Eric Carty at (702) 293-8129.

From InkStain (John Fleck):

Today’s release of the Bureau of Reclamation’s August 24-month study is what in my old newspaper days we would have called “a great news peg”. It’s been clear for a while that we’ll likely have a first-ever federal shortage declaration in the Lower Colorado River Basin in 2020, and that chance is growing. But in the interests of never letting a good Colorado River shortage news peg go unused….

A shortage on the Colorado River, which would force water supply cutbacks for users in Arizona and Nevada, is likely in January 2020, according to a new analysis from federal scientists released Thursday.

In the Bureau’s “most likely” scenario – essentially the median of a bunch of model runs reflecting various hydrologic scenarios under the current rules – Lake Mead would end 2019 at elevation 1,070.35. Anything below 1,075 and Arizona and Nevada have to reduce their use of Colorado River water.

This will happen even though Lake Mead is forecast to get more “bonus water” in 2019 – water released from Lake Powell above and beyond the Upper Basin’s legal compact delivery obligations* of 8.23 million acre feet. The current projected release is 9 million acre feet, but despite that bonus water, Lake Mead is projected to drop 9 feet next year.

I’m in the midst of a book chapter diving into this stuff, so let me obsessively share numbers because I spent all day staring at them, and they might shed some light on where the problem lies. That “bonus water” delivered by the Upper Basin is a big clue.

The Upper Basin has only been using ~4-4.5 million acre feet of water a year, well below its Colorado River Compact entitlement of 7.5maf.

Since 2000, the Upper Basin has delivered 9.7 million acre feet above the amount required under the current rules (8.23 million acre feet per year). So the Upper Basin is a) using less water, and b) delivering more to the Lower Basin. (Brad Udall, who’s been helping me think about all these numbers, sent me the graph above showing the accumulating surplus.)

By the time next year is over, the Lower Basin will have gotten 10 million acre feet of “bonus water” in the 21st century. 10 million acre feet more than the Colorado River Compact requires. Yet Lake Mead keeps dropping. It’s pretty clear where the “supply-demand imbalance” lies here. Looking at you, my Lower Basin friends.

Everyone can plausibly argue that they’re living within the rules here, but if we keep defending our actions with “But the rules say it’s OK!” the Colorado River system is going to crash.

From The Denver Post (Bruce Finley):

The feds are imploring Western states to do more now to cut water use.

A U.S. Bureau of Reclamation forecast issued Wednesday for water in the Colorado River — an over-subscribed lifeline for 40 million people — anticipates declaration of a shortage in September 2019 that would trigger the reduced water releases from federal reservoirs in “lower basin” states including Nevada and Arizona.

Colorado and other “upper basin” states Utah, Wyoming and New Mexico would face increased scrutiny of flows from headwaters into the Lake Powell reservoir. On Wednesday, Lake Powell measured 49 percent full and Lake Mead measured 38 percent full.

“Water stored in Lake Mead and Lake Powell has blunted the impacts of the ongoing drought and helped ensure consistent, reliable water and power,” said Brent Rhees, the bureau’s regional director for the upper basin. “We must continue to work to protect water in the basin. Completing drought contingency plans this year will provide better certainty. …. We can’t afford to wait for a crisis.”

Colorado Water Conservation Board Director Rebecca Mitchell said “there’s no doubt” managing the river presents challenges. “Realistic predictions on the Colorado River are for increasing demand and decreasing supply,” Mitchell said.

Declaration of a water shortage along the Colorado River would be unprecedented. Federal officials are committed to waiting until the water level in Lake Mead drops below the elevation of 1,075 feet above sea level. Then they’d cut deliveries, first targeting Arizona, Nevada and Mexico.

The water level on Wednesday: 1,078 feet.

“We’re within three feet. We’re not going to declare a shortage in 2019,” agency spokesman Marlon Duke said. “There’s a 52-percent chance we will have to declare a shortage in 2020. … We cannot just sit back and think the river is going to provide all the water we need, especially as our cities continue to grow. It all depends on what Mother Nature sends us next year.”

[…]

“We see this train coming, and we’re trying to get ready for it,” said James Eklund, Upper Colorado River Basin commissioner for Colorado, who negotiates river matters with commissioners from the other states, including California.

“Right now we’re OK. If they declare a shortage in the lower basin, it is going to pull more water out of Lake Powell. That would mean we are going to have to put more water into it,” Eklund said.

“The ‘shortage’ is like a yellow traffic signal that says, ‘Hey. Watch out. You’ve gotta be mindful of demands exceeding supply to such a degree that our system doesn’t work.’”

[…]

“We see this train coming, and we’re trying to get ready for it,” said James Eklund, Upper Colorado River Basin commissioner for Colorado, who negotiates river matters with commissioners from the other states, including California.

“Right now we’re OK. If they declare a shortage in the lower basin, it is going to pull more water out of Lake Powell. That would mean we are going to have to put more water into it,” Eklund said.

“The ‘shortage’ is like a yellow traffic signal that says, ‘Hey. Watch out. You’ve gotta be mindful of demands exceeding supply to such a degree that our system doesn’t work.’”

U.S. Bureau of Reclamation Commissioner Brenda Burman has warned states they must act. Burman demanded “drought contingency plans” by the end of the year. The publication of the Colorado River forecast covering the next two years is expected to spur planning, if not immediate smarter use of water.

Federal government scientists have concluded that climate change is creating conditions in the Colorado River Basin that are more variable with more extreme precipitation and more extreme drought. Scientists say precipitation increasingly will come from rain, rather than snow, as temperatures increase. The reservoirs constructed along the river have become increasingly important in easing the impact during a dry period that began 18 years ago and ranks among the driest periods in 1,200 years.

The forecast says river flows into Lake Powell from Colorado and other upper basin states, from snowpack, probably won’t exceed 75 percent of average next year. It says 8.23 million acre-feet of water will flow from Lake Powell to Lake Mead in 2019. That’s more than the amount expected to flow into Lake Powell.

Colorado, Wyoming and Utah depend heavily on mountain snowpack and have been delivering water to Lake Powell as required under the Colorado River Compact. The efforts in these states to develop a plan for conservation should a shortage be declared reflects a common interest of states in managing the river cooperatively — avoiding a federal intervention to control flows into and out of reservoirs.

That plan will be done by the end of the year, Eklund said.

“We in the upper basin face water shortages every year because the nation’s two largest reservoirs sit below, not above, us. We have to work with whatever falls from the heavens. Anytime we have to administer water under our priority system, someone in the upper basin is taking a shortage. That happens every year,” he said.

“We have ways to use less water. We fallow fields. We take water out of pipelines. We conserve. But we have less snow to work with than in the past and more people than ever reliant on the Colorado River system,” Eklund said…

Water advocacy groups embraced the forecast as evidence the West’s water challenges are reaching a critical point.

People in the seven southwestern states “must learn to live with less water,” said Kim Mitchell of the Boulder-based Western Resource Advocates. “Unless we take decisive, proactive steps now, major water users, farmers, cities, businesses, and the environment all will lose water. … Leaders at all levels throughout the basin must understand that more water is being pulled out of the Colorado River than is being replaced and the problem is compounded by a long-term drought and climate change.”

From The Las Vegas Review-Journal (Henry Brean):

Despite another dry winter on the Colorado River, Lake Mead and the millions of people who rely on it will avoid a water shortage for at least one more year.

According to new projections from the Bureau of Reclamation, there will be just enough water in the reservoir east of Las Vegas at the end of 2018 to stave off a first-ever federal shortage declaration that would trigger mandatory cuts in Nevada and Arizona.

But without a significant change in the weather — and additional human intervention — shortage could be unavoidable in 2020.

Forecasters now expect Lake Mead to finish the year with a surface elevation of 1,079 feet above sea level, four feet above the trigger point for a shortage. That’s actually an improvement in the near-term forecast since last month, when officials were predicting a lake elevation of 1,077 by year’s end.
Meanwhile, the outlook for next year has worsened somewhat, with a projected lake level of 1,070 — well below the shortage line — by Jan. 1, 2020.

Colorado River expert John Fleck said water users in Nevada, Arizona, California and Mexico have “put off the inevitable” so far with water conservation measures that have reduced some strain on the over-taxed system…

Once a shortage is declared, Nevada will have to reduce its annual Colorado River use by 4 percent, while Arizona takes an 11 percent cut. Shortage cuts are not expected to directly impact water users in Southern Nevada, at least not at first…

The valley gets 90 percent of its water from the Colorado River by way of Lake Mead. Southern Nevada Water Authority officials say the community has already conserved more than enough to easily absorb a 4 percent cut to its river allotment, but prolonged shortages and deeper cuts could make it hard to meet future water demands as the community continues to grow…

The worst winters

From April to July, the Colorado River swells with snow melt from the mountains of Colorado, Utah and Wyoming. But dry winters generally lead to below-average flows. Here are the 10 lowest April-to-July flows on the Colorado over the past 50 years by their percentage of the long-term average:

2002: 13 percent
1977: 17 percent
2012: 29 percent
2013: 36 percent
2018: 36 percent
1981: 42 percent
1990: 44 percent
1989: 48 percent
2004: 49 percent

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