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November 3, 2021  |  Written by Daniel F. McCarl

As the 2021 Water Year Closes, a Look Forward, and Back, at Colorado River Implementation of the DCP and the Drought Operations Response Agreement

At the close of the 2021 Water Year in October, the Colorado River basin remains in significant drought, despite summer monsoons and early fall precipitation across the West. This summer, the Upper Basin States to the Colorado River Compact – Colorado, New Mexico, Utah, and Wyoming – implemented the first ever coordinated release of 181,000 acre-feet (AF) of water from three reservoirs on the Colorado River to increase storage supplies at Lake Powell. While 181,000 AF represents a relatively small amount of water relative to Lake Powell’s existing storage supplies or the Upper Basin’s delivery obligations under the Compact, the release signaled the beginning of a new stage of critical planning around Compact compliance. As those water releases come to a close by December 2021, all stakeholders are closely watching Reclamation’s Colorado River forecasts and activities in the Colorado River basin to prepare for Water Year 2022.

The unprecedented 181,000 AF of storage releases in the Colorado River’s Upper Basin have been made from the Flaming Gorge Reservoir (125,000 AF), the Blue Mesa Reservoir (36,000 AF) and the Navajo Reservoir (20,000 AF) (collectively, the “Initial Units”) and are being made pursuant to the emergency response provisions of a 2019 agreement among the Upper Basin States and the Secretary of the Interior (Secretary) known as the “Drought Response Operations Agreement” (DROA or Agreement). The DROA provides for releases from the Initial Units when the storage elevation in Lake Powell approaches critical levels below which Glen Canyon Dam can no longer generate hydropower.

The DROA is one of the three primary components that make up the Upper Basin’s broader 2019 Drought Contingency Plan or “DCP” (the other two components being a weather modification program and a “Demand Management” program). The 181,000 AF of storage releases from the Initial Units, along with other key changes made this summer – including declaration of a “Tier 1 shortage”  for the Lower Basin, and a reduction in the amount of water normally released from Lake Powell for Water Year 2022 – underscore the impact of the decades-long drought in the Colorado River system.

The following map shows where the Initial Units are located on the Colorado River system:

Colorado River Compact Basics

The 1922 Colorado River Compact requires that the Upper Basin States deliver a rolling average of 75 million acre-feet (MAF) to the Lower Basin at Lee’s Ferry, Arizona every 10 years, corresponding to an average annual release of approximately 7.5 MAF. The Upper and Lower Basins also share a 1.5 MAF/year delivery obligation to Mexico according to the terms of a 1944 Treaty. If split evenly between the Upper and Lower Basins, the 1944 Treaty obligation would bring the Upper Basin’s total delivery obligation to an average of 8.25 MAF/year.

Although the Upper Basin has always met its 75 MAF delivery obligation to the Lower Basin under the Colorado River Compact, the drought in the Colorado River Basin has continued virtually unabated for two decades. Thus, water storage in Lake Powell and Lake Mead – the two primary savings accounts for the Upper and Lower Basins under the Compact – have reached historic lows. At present, water storage in Lake Powell is less than 30% of capacity (approximately 7.2 MAF of 24.3 MAF).

The DROA is one of the primary response measures that the Upper Basin States adopted just two years ago to protect against the effects of prolonged drought in the Colorado River Basin. Along with Compact compliance, the DROA is intended to ensure that enough water remains in Lake Powell to allow hydroelectric power generation at Glen Canyon Dam to continue. Lake Powell requires a surface elevation of 3,490 feet to allow for power generation, referred to as the “minimum power pool” elevation.

The 2019 Drought Response Operations Agreement

The DROA sets a Lake Powell target elevation of 3,525 feet relative to sea level as the “Target Elevation” to minimize the risk that the Upper Basin will be unable to meet its obligations under the Colorado River Compact and to minimize the risk that Lake Powell storage will fall below minimum power pool elevation (i.e., 3,490 ft.). In the DROA the Upper Basin States and the Secretary of the Interior agreed that the Target Elevation of 3,525 feet “appropriately balances the need to protect infrastructure, compact obligations, and operations at Glen Canyon Dam, as storage approaches minimum power pool with the Upper Division States’ rights to put Colorado River System water to use.”

The DROA sets forth a series of thresholds tied to hydrologic forecasts that, when crossed, require the Upper Basin States to take actions to maintain the Target Elevation in Lake Powell. However, the DROA also includes emergency response provisions under which the Secretary, after consulting with the Upper Basin States, can direct releases from the Initial Units independent of the States “in the event that actual hydrology or actual operating experience demonstrate an imminent need to protect the Target Elevation. . . .” The releases made this year were at the direction of the Secretary pursuant to the DROA’s emergency response provisions after consultation with both the Upper Basin and Lower Basin States, continuing the long history of cooperative management between Reclamation and the seven Basin States.

In July, when releases from the Initial Units began, the elevation of Lake Powell was 3,565 feet, or 40 feet above the Target Elevation. As shown on the schedule below, the 181,000 AF of releases from the Initial Units are planned to continue through December:

Although future releases may be more substantial, the collective release of 181,000 AF from the Initial Units this year correspond to just a 3-foot increase in the elevation of Lake Powell. The current elevation of Lake Powell is approximately 3,545 ft., 20 feet above the Target Elevation, and 20 feet less than Lake Powell’s elevation when the releases from the Initial Units began in July.

The Upper Basin States’ Ongoing DROA Obligations

Separate from the Secretary’s emergency response authority, the DROA sets forth a series of thresholds tied to hydrologic forecasts that, when crossed, require the Upper Basin States to take actions to maintain the Target Elevation in Lake Powell. These thresholds were crossed this summer such that, along with causing the Secretary to undertake emergency action, the DROA set in motion a broader planning effort by the Upper Basin States to help maintain the Target Elevation in Lake Powell.

The formal trigger for the Upper Basin States to initiate planning under the DROA is tied to hydrologic forecasts published each month by the Bureau of Reclamation known as the Bureau’s “24-Month Study” (preparation of the Bureau’s monthly 24-Month Study is also a condition of the DROA). As it sounds, the Bureau’s 24-Month Study is a rolling monthly forecast of storage amounts and reservoir elevations at Lake Powell and other Colorado River storage project structures (including the Initial Units) for the upcoming 24 months. If a monthly study shows a certain likelihood that Lake Powell will fall below the Target Elevation within the next two years, the Upper Basin states must begin developing a draft “Drought Response Operations Plan” (Drought Plan) to plan for future operational adjustments or releases at the Initial Units.

Earlier in 2021, the January 2021 Study showed a least probable risk for Lake Powell to drop below a Target Elevation of 3,525 feet above sea level by 2022. That triggered obligations for the upper basin states to have a monthly call and for Reclamation to provide monthly modeling. By May 2021, the 24-Month Study showed the elevation of Lake Powell declining to 3,525.57 feet – the Target Elevation – as early as March 2022 under its “Most Probable” forecast. The Bureau’s “Most Probable” forecast reflects a median hydrologic condition which statistically would be exceeded 50% of the time. As a result of this forecast, the DROA required that the Upper Basin States “begin developing a Draft” Drought Plan. In the Drought Plan, the Upper Basin States are to consider if, when and how to make additional future releases from the Initial Units to maintain the Target Elevation.

The DROA only broadly sets forth what the Drought Plan must include. The Agreement does not require or specify the timing or amounts of releases from the Initial Units. In formulating a Drought Plan, the DROA requires that the Upper basin States first consider the efficacy of making “operational adjustments at Glen Canyon Dam” before considering operational adjustments (including releases) from the Initial Units. The DROA also requires that the Drought Plan account and plan for the “recovery” of storage released to Lake Powell from the Initial Units. Formulating the Drought Plan is complicated by the myriad storage and delivery obligations, as well as the web of state and federal requirements, that govern management of the Initial Units.

The 2022 Water Year Under the DCP and DROA

In its October 24-Month Study, the Bureau estimated that Lake Powell would fall below the Target Elevation to 3,523 feet by February 2022 under its Most Probable hydrologic scenario. Further, the Bureau found “a 5% chance that Lake Powell will fall below minimum power pool elevation of 3,490 feet in 2023 and 17% in 2024.” The October 24-Month Study also implemented an updated forecasting effort to include updated climate conditions and data sets, which decreased the inflow forecasts further. Thus, if current hydrologic conditions continue, the Upper Basin States, through the Drought Plan and other measures, are expected to take significant and swift actions to maintain the Target Elevation in Lake Powell and to prevent storage levels from falling below the minimum power pool.

The Bureau’s May 2021 24-Month Study triggered the Upper Basin States’ obligation to “begin drafting a Draft” Drought Plan to protect storage levels in Lake Powell. The DROA goes on to require that this draft Drought Plan be “finalized” when another trigger is met –­ namely, when the Bureau’s April 24-Month Study (in this case the Bureau’s April 2022 24-Month Study) projects Lake Powell to be at or below the Target Elevation at any time in the next 12-month period under its “Most Probable” hydrologic scenario. Thus, at present, triggers under the DROA have been met that require the Upper Basin States to begin developing a draft Drought Plan to maintain the Target Elevation at Lake Powell, but the trigger for the States to finalize the Drought Plan has not been met.

According to the DROA, before the Upper Basin may finalize its Drought Plan, it must consult with the Lower Basin States and obtain the approval of the Secretary. Notably, the Upper Basin States need not obtain the approval of the Lower Basin States but only need to consult with and “be available to the … questions or concerns” of the Lower Basin States. Based on the terms of other overarching agreements that govern operations under the Colorado River Compact (namely, the 2007 “Interim Guidelines”), the Upper Basin’s Drought Plan generally may not extend beyond December 31, 2025, except to allow the Initial Units to recover (i.e., make up for lost storage).

While it is not clear what terms the Upper Basin States’ Drought Plan might include or provide as to future releases from the Initial Units, what is clear is that there remains a significant risk that Lake Powell could fall below the minimum power pool elevation in the near term. The impacts of more releases may play out in greater efforts and more rapid actions from Colorado River basin water managers to encourage and enforce water conservation measures throughout the basin. For example, Reclamation just announced a webinar scheduled on November 5, 2021 to review the Lower Basin States’ contemplated approach and responsive actions under the DCP for managing a Lake Mead elevation predicted to drop below 1,030 feet by July of 2023.  The cooperative model for planning in the Colorado River Basin planning efforts in the DCP and DROA seemed to have been implemented just in time as the West confronts ongoing and increasing climate change and drought. All the various stakeholders in the basin are grappling with drought levels in storage that have happened more quickly than expected, with various triggering events moving quickly to create action. Proactive local planning should be the expectation for the 2022 Water Year ahead.

For further information please contact Dan McCarl at or Ramsey Kropf at

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