Lake Mead, August 2022, by USBR Photographer. Christopher Clark

SoCAL WATER: The impact of Reclamation’s SEIS alternatives on Metropolitan’s Colorado River supplies; Abundant precipitation refills storage

Metropolitan’s One Water and Stewardship Committee meeting on May 8  featured a presentation on the Bureau of Reclamation’s draft Supplemental Environmental Impact Statement (SEIS) and what it means for Metropolitan’s Colorado River supplies. They also discussed how the improved water supply will affect Lake Mead and Southern California’s water supplies.

Colorado River draft Supplemental Environmental Impact Statement (SEIS)

Shanti Rosset, Program Manager for Metropolitan, updated the committee members on the Colorado River draft Supplemental Environmental Impact Statement (SEIS) and its potential effects on Metropolitan’s water supplies.

Last November, the Bureau of Reclamation initiated the process to amend the 2007 guidelines.  On April 14, Reclamation published the draft SEIS in the Federal Register, triggering a 45-day comment period.  While the draft SEIS notes that California and the other six Colorado  Basin states submitted alternatives, Reclamation developed three alternatives for analysis:

  • Alternative one reduces deliveries to the lower basin according to priority.
  • Alternative two reduces deliveries to all lower basin water users on a pro-rata basis.
  • The no-action alternative, a NEPA requirement, includes the existing guidelines, Treaty Minute 323, and Drought Contingency Plan agreements.

The draft SEIS proposes revising the near-term operation of Glen Canyon and Hoover Dams starting in 2024; the modified operating guidelines would inform potential operations in 2025 and 2026.

Ms. Rosset noted that Reclamation did not identify a preferred alternative in the draft SEIS and these alternatives may be modified in the final SEIS and Record of Decision.  “Before issuing a record of decision, the components of an action must be analyzed first, so the alternatives can be looked at as bookends that allow an analysis of the full range of impacts to the final agency action,” she said.

Common elements of the alternatives

Ms. Rosset said there are many common elements between the two alternatives.  Both make changes to Lake Powell and Glen Canyon Dam operations, reducing releases when Lake Powell is at or below elevation 3575 to protect elevation 3500, below which the ability to generate hydropower could be lost.   Both alternatives increase lower basin shortages.  And they both model shortage and drought contingency plan contributions of 2.083 million acre-feet in 2024 and 4 million acre-feet in 2025 and 2026.

Both alternatives proposed changes to the tiers in Lake Powell and releases from Glen Canyon Dam; the table shows the current tiers on the left and the modified/new tiers on the right.  Under both alternatives, releases from Lake Powell are reduced when the reservoir elevation is below 3575.  In the new lower elevation release tier, the initial release would be 6 million acre-feet, with April adjustments up to 8.23 million acre-feet.

The lower elevation balancing tier is replaced with a protection level.  Under the current rules, Lake Powell can release no less than 7 million acre-feet in a year.  Under the revised tiers, releases from Lake Powell could be less than 6 million acre-feet in a year.

Ms. Rosset noted that releases from Powell are also used to make treaty deliveries to Mexico.  “Under the new proposed Lake Powell tiers, there could be a year when releases from Lake Powell are 6 million acre-feet,” she said.  “And out of that, between 1.4 and 1.5 million acre-feet would be for treaty deliveries leaving only 3.5 million acre-feet or less for the entire lower basin.”

Alternative 1

Alternative one administers new shortages according to the priority system.  With this alternative, Reclamation modeled shortages in two stages.

In stage one, Nevada takes 4% of the shortage, Arizona takes 96%, and California takes no shortages.  California begins to share in shortage when no Arizona fourth priority water is available; the Central Arizona Project and other post-1968 rights are fourth priority.   In stage two, Nevada takes 4%, Arizona takes 19.6%, and California takes 76.4%.  When lower basin cuts reach 4 million acre-feet under the priority alternative, all water rights not present perfected rights (or PPRs) in California are shorted; even a few PPRs are shorted at the highest volume of shortages.

The table below shows lower basin states’ shortages and DCP contributions by state under Alternative 1 for 2024.  The boxes outlined on the left highlight the new shortages that Arizona and Nevada would take; the red box on the right shows the total shortages and DCP contributions for the year.  The maximum amount in 2024 is 2.083 million acre-feet.

The blue box shows where Lake Mead was forecast to operate in the April 24-month study.  In this range, Arizona would take an additional 511,000 acre-feet of shortage, and Nevada would take an additional 22,000 acre-feet of shortage.

The table below shows lower basin states’ shortages and contributions by state under Alternative 1 for 2025-2026.  California begins to take additional shortages when Lake Mead drops below 1040, up to a maximum of 1.376 million acre-feet.

The red box on the right shows the shortages and DCP contributions would range annually from 400,000 acre-feet to 4 million acre-feet for the lower basin.  The blue box shows where Lake Mead was forecast to operate in 2025 according to the April 24 months study.

Alternative 2

Alternative two reduces deliveries to all lower basin water users on a pro-rata basis.  The percentage of reduction is based on Lake Mead elevations.  The box below shows the percentage of additional reductions that peak at 15.55% at elevation 1035 to 1040.

The blue box shows where Lake Mead is forecast to operate in 2024, according to the April 24-month study.  Between 1050 and 1075, a 7.11% reduction would be applied to all lower basin water users.

Improved conditions

Conditions in the basin have changed significantly since Reclamation initiated the SEIS process last fall.  The unregulated inflow into Lake Powell in the September 24-month study was 8.3 million acre-feet or 86% of average; in the April 24-month study, the forecast went up to 14.47 million acre-feet or 151% of average.

The five-year projections show a significant reduction in the risk of Lake Powell and Lake Mead falling under critical reservoir elevations.  Last January, the risk of Lake Powell reaching 3525 ranged from 37% in 2024 to 23% in 2026; that has declined to 0% and 2024 and 2025 and 3% in 2026.

Next steps for the SEIS

The public comment period will end on May 30.  Reclamation will then review and respond to public comments and work towards a final SEIS that would identify a preferred alternative.  Then, in late July or early August, Reclamation is anticipated to issue the Record of Decision that would be used for reservoir operations in 2024.  Ms. Rosset noted that discussions with the basin states and the Department of Interior are ongoing.

A new possible path forward for the Colorado River-?

States near historic deal to protect Colorado River

“After nearly a year wrestling over the fate of their water supply, California, Arizona and Nevada — the three key states in the Colorado River’s current crisis — have coalesced around a plan to voluntarily conserve a major portion of their river water in exchange for more than $1 billion in federal funds, according to people familiar with the negotiations. … But thorny issues remain that could complicate a deal. The parties are trying to work through them before a key deadline at the end of the month, according to several current and former state and federal officials familiar with the situation. … ”  Read more from the Washington Post (gift article).

Deven Upadhyay, Assistant General Manager and Chief Operating Officer, said that one concern was that the comments by the basin states would have a ‘war footing’ because they will be outlining deficiencies, so if litigation is necessary further down the road, they will have exhausted all administrative remedies through the process.

He also suggested that a deal may be in the works.  “California, along with Arizona, are committed to reductions going forward,” he said.  “Remember that California put 400,000 acre-feet in reductions on the table that would be compensated by the federal government.  So that, coupled with the package of reductions in Nevada and Arizona that would be compensated by the federal government and how different conditions are on the river since the Bureau started this SEIS process – we think that there may be a path to navigate for reductions that result in a sustainable system for the next few years without really draconian reductions.  We’re hopeful for an opportunity to work with the federal government to find that as the outcome instead of alternative one or two in this process.  And there will be more to come on that.  A lot is going on behind the scenes to try to figure our way through this right now.”

Director Smith asked how much will carry through to the 2026 new guidelines.

“I think a lot of what has led up to this point, even outside of the SEIS process, was positioning related to the post-2026 negotiations and where we could land in commitments of reductions that the federal government funds.  So if we see a good sustainable operation with Mead and Powell for the next three years, that could create a path for us to sit down and start those negotiations sooner rather than later and, to some degree, put some of the short-term discussions behind us.  But we very much believe that things like the evaporative and system losses proposal that was put out there that led up to where we are now in this SEIS process, that was positioning for the long-term negotiations.”

Abundant supplies mean Metropolitan will put water in Lake Mead

Several months ago, Metropolitan’s plan for the Colorado River was to reduce the use of the Colorado River and to implement conservation as necessary to not draw from ICS storage in Lake Mead.  The forecast at the time was that Lake Mead could fall below 1025 in 2024, meaning that Metropolitan couldn’t draw from the ICS supplies, although those supplies could be used to make the required DCP contributions.

All that’s changed now, said Bill Hasencamp.  This year, Colorado River supplies will be divided between deliveries to Metropolitan’s service area, paying the balance of water owed to the Coachella program, and increasing storage in Lake Mead.  Fallowing programs such as the PVID program can be turned over to the federal government, saving up to $100 million at the current value.

“Instead, we can take more State Project water in, turn those programs with the federal government, reduce our costs, and then even deliver more water to Lake Mead to cover the supplies over the next four years,” he said.  “So we can leave water in Lake Mead to cover the supplies this year but leave even more to cover those programs in future years.  So that’s a new opportunity that we’re looking at.”

Too much water?

Metropolitan’s current supply estimate is approximately 3 million acre-feet, which includes supplies from the Colorado River Aqueduct, State Water Project, and Article 21.  The current demand estimate is around 1.6 million acre-feet, which leaves about 1.4 million acre-feet of supplies to be managed.

Noosha Razavian, Associate Resource Specialist, said they are putting as much water into storage as possible, including State Water Project carryover flexible storage, Central Valley banking programs, in-region storage, and Lake Mead.  Staff is exploring options for putting water into Lake Mead, such as increasing ICS storage, prepaying future obligations, or adding it as system water funded through the Inflation Reduction Act.

However, there are some constraints, she said.  They plan on maximizing State Water Project carryover supplies, but because San Luis is full and likely will remain full for the remainder of this year, there will be little room for carryover space.  In addition, the flooding in the Central Valley is currently limiting the ability to put water into those storage programs at this time.

With these abundant supplies, staff is projecting that storage accounts will be refilled with potentially 3.3 million acre-feet in dry-year storage by the end of the year.  However, Ms. Razavian said that while the goal is to manage all of the 1.43 million acre-feet of supplies, staff still hasn’t identified where to put about 375,000 acre-feet of water.

Mr. Upadhyay noted the situation is not unprecedented; back in 2017 and 2019, they had to leave water on the table.  “We were doing everything we could to manage water into storage as much as possible.  But it’s not unprecedented for us to be in that situation.  And then 100% allocation with all the article 21 we’ve already received, it’s likely to be the case again.”

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