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November 24-Month Study

Date: November 15, 2023 

From: River Operations Group, Salt Lake City

To: All Colorado River Annual Operating Plan (AOP) Recipients

Current Reservoir Status 

October Inflow

(unregulated)

(acre-feet)

Percent of

Average 

(percent)

November 14

Midnight Elevation

(feet)

November 14,

Midnight Reservoir

Storage (acre-feet)

Fontenelle 52,800 117 6496.35 261,770

Flaming Gorge 68,700 129 6029.07 3,229,395

Blue Mesa 29,800 82 7491.18 586,936

Navajo 12,300 32 6045.09 1,115,521

Powell 324,300 72 3572.18 8,683,392

Expected Operations 

The operation of Lake Powell and Lake Mead in the November 2023 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 2023 

Annual Operating Plan (AOP). Pursuant to the Interim Guidelines, the August 2022 24-Month Study

projections of the January 1, 2023, system storage and reservoir water surface elevations set the

operational tier for the coordinated operation of Lake Powell and Lake Mead during 2023. 

Consistent with Section 2.D.1 of the Interim Guidelines, a Shortage Condition consistent with Section

2.D.1.b is governing the operation of Lake Mead for calendar year (CY) 2023. In addition, Section III.B of

Exhibit 1 to the Lower Basin Drought Contingency Plan (DCP) Agreement will govern the operation of

Lake Mead for CY 2023. Efforts to conserve additional water in Lake Mead under a 2021 Lower Basin

Memorandum of Understanding (MOU) to facilitate near-term actions to maintain the water surface 

elevation of Lake Mead and additional conservation efforts under the Lower Colorado River Basin System

Conservation and Efficiency Program (LC Conservation Program) will also take place in CY 2023. 

The August 2023 24-Month study projected the January 1, 2024, Lake Powell elevation to be less than

3,575 feet and at or above 3,525 feet and the Lake Mead elevation to be at or above 1,025 feet. Consistent

with Section 6.C.1 of the Interim Guidelines the operational tier for Lake Powell in water year (WY) 2024 

will be the Mid-Elevation Release Tier and the water year release volume from Lake Powell will be 7.48 

million acre-feet (maf). 

The 2022 Drought Response Operations Agreement (DROA) Plan1 for May 2022 through April 2023 was 

amended to suspend 2022 DROA Plan releases as of March 7, 2023. A total DROA release of

approximately 463 thousand acre-feet (kaf) occurred under the 2022 DROA Plan. Reclamation will attempt

1 For more information: https://www.usbr.gov/uc/DocLibrary/Plans/20220429-2022DroughtResponseOperationsPlanApprovalMemo-508-DOI.pdf. 
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to maximize DROA recovery in the Upper Initial Units in WY 2023 and through April 2024. Reclamation

will provide monthly DROA accounting, including DROA releases and recovery, which can be found online

at: https://www.usbr.gov/dcp/DROSummarySheet.pdf. 

In May of 2023, the DROA Parties agreed to the 2023 DROA Plan. The 2023 DROA Plan does not include

any DROA releases, but rather provides for recovery of prior DROA releases from the units upstream of

Powell.

Reclamation will continue to carefully monitor hydrologic and operational conditions and assess the need

for additional responsive actions and/or changes to operations. Reclamation will continue to consult with

the Basin States, Basin Tribes, Mexico, and other partners on Colorado River operations to consider and 

determine whether additional measures should be taken to further enhance the preservation of these

benefits, as well as recovery protocols, including those of future protective measures for both Lakes 

Powell and Mead. 

The August 2023 24-Month Study projected the January 1, 2024 Lake Mead elevation to be below 1,075 

feet and above 1,050 feet. Consistent with Section 2.D.1 of the Interim Guidelines, a Shortage Condition

consistent with Section 2.D.1.a will govern the operation of Lake Mead for CY 2024. In addition, Section

III.B of Exhibit 1 to the Lower Basin DCP Agreement will also govern the operation of Lake Mead for CY

2024. Lower Basin projections for Lake Mead take into consideration updated water orders to reflect

additional conservation efforts under the LC Conservation Program.

The 2024 operational tier determinations for Lake Powell and Lake Mead will be documented in the 2024 

AOP, which is currently in development.

Current runoff projections into Lake Powell are provided by the National Weather Service’s Colorado Basin

River Forecast Center. The observed unregulated inflow into Lake Powell for the month of October was

0.323 maf or 71% of the 30-year average from 1991 to 2020. The November 2023 unregulated inflow

forecast for Lake Powell is 0.360 maf or 86% of the 30-year average. The observed 2023 April through July

unregulated inflow is 10.62 maf or 166% of average. The observed WY 2023 unregulated inflow is 13.42 

maf or 140% of average. 

The draft 2024 AOP is available online at:

https://www.usbr.gov/lc/region/g4000/AOP2024/AOP24_draft.pdf

The 2023 AOP is available online at:

https://www.usbr.gov/uc/water/rsvrs/ops/aop/AOP23.pdf. 

The Interim Guidelines are available online at:

https://www.usbr.gov/lc/region/programs/strategies/RecordofDecision.pdf. 

The Colorado River DCPs are available online at:

https://www.usbr.gov/dcp/finaldocs.html. 

The 2021 Lower Basin MOU is available online at: 

https://www.usbr.gov/lc/region/g4000/2021_MOU.pdf. 

The Upper Basin DROA is online at:

https://www.usbr.gov/dcp/droa.html. 

The Upper Basin Hydrology Summary is available online at:

https://www.usbr.gov/uc/water/crsp/studies/24Month_11_ucb.pdf. 

Information on the LC Conservation Program is available online at: 

https://www.usbr.gov/lc/LCBConservation.html. 
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Fontenelle Reservoir 

As of November 02, 2023, the Fontenelle Reservoir pool elevation is 6497.27 feet, which amounts to 80 

percent of live storage capacity. Inflows for the month of October totaled approximately 52,846 acre-feet

(af) or 117 percent of average. 

Current release rate is set at 1,100 cfs. Winter base flow release will be set in mid-November after

receiving the November forecasts. Winter base flow will be set to a constant release rate from midNovember to approximately mid-March, depending on winter icing conditions. Pending hydrology, 

winter releases will be approximately 1,125 cfs. 

The November final forecast for unregulated inflows into Fontenelle for the next three months projects

near average conditions. November, December, and January Most Probable inflow volumes amount to

45,000 af (107 percent of average), 35,000 af (109 percent of average), and 32,000 af (107 percent of

average) respectively. 

The next Fontenelle Working Group meeting is April 18, 2024 at 10 AM MDT and location is pending. 

Details on the meeting will be provided as we get closer to the meeting date. Prior Fontenelle Working 

Group meeting minutes are available online on USBR’s website at

https://www.usbr.gov/uc/water/crsp/wg/ft/ftcurrnt.html. The Fontenelle Working Group is an open public

forum for information exchange between Reclamation and other parties associated with the operation of

Fontenelle Reservoir. 

Flaming Gorge Reservoir

As of November 1, 2023 (end of day), Flaming Gorge Reservoir pool elevation is 6029.15 feet, which

amounts to 88 percent of live storage capacity. Unregulated inflow volume for the month of October is

approximately 69,000 af, which is 129 percent of the average October unregulated inflow volume. 

Flaming Gorge Dam operations are in an average hydrologic classification for the month of November

and are projected to remain in the average hydrologic classification through the remainder of the base

flow period. The autumn average daily release remains within the average hydrologic classification range 

of 1,500 cfs to 2,400 cfs in Reach 2, measured at the Jensen USGS Gage. Current average daily release is

approximately 1,500 cfs. This data is considered the most likely scenario given the current forecast, is

general, and is subject to changing conditions.

The November unregulated inflows into Flaming Gorge for the next three months projects near average. 

November, December, and January forecasted unregulated inflow volumes amount to 56,000 af (113 

percent of average), 39,000 af (118 percent of average), 45,000 af (112 percent of average), respectively. 

Reclamation is planning to hold Flaming Gorge Working Group meetings tentatively on March 21, 2024 

and April 17, 2024, at 10:00 am (and Teams virtual meeting). The location is TBD. The Flaming Gorge

Working Group is an open public forum for information exchange between Reclamation and the

stakeholders of Flaming Gorge Dam. The public is encouraged to attend and comment on the operations

and plans presented by Reclamation at these meetings. Meeting notes from past Working Group

meetings are posted on the Working Group webpage. For more information on this group and these

meetings please contact Alex Pivarnik at (385) 475 – 8329. 
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Aspinall Unit Reservoirs

As of November 7, 2023, releases from Crystal Dam are approximately 850 cfs. Flows of the Gunnison

River in the Black Canyon are being maintained at about 320 cfs while the Gunnison Tunnel is diverting

520 cfs. Flows in the Whitewater Reach of the Gunnison River are about 1,650 cfs.

The unregulated inflow volume in October to Blue Mesa was 30,000 af (81 percent of average).

Unregulated Inflow volumes forecasted for Blue Mesa for the next three months (November, December, 

January) are projected to be: 28,000 af (93 percent of average), 25,000 af (100 percent of average) and 

23,000 af (96 percent of average), respectively. The November 24-Month Study will be reflective of these

new forecasted inflows. 

The forecasted 2024 water year unregulated inflow volume to Blue Mesa is projected to be 840,800 af (93 

percent of average). The water supply period (April-July) for 2024 is forecasted currently for an 

unregulated inflow volume of to be 595,000 af of unregulated inflow (94 percent of average).

The Aspinall Unit Operations Group is an open public forum for information exchange between

Reclamation and the stakeholders of the Aspinall Unit. The public is encouraged to attend and comments

on the operations and plans presented by Reclamation at these meetings. Meeting notes from past

working Group meetings are posted on the Operations Group webpage. For more information on this

group and these meetings please contact Erik Knight in the Grand Junction Area Office at (970) 248-0629. 

The next Operations Group meeting will be held January 18, 2024 at 1:00 p.m., in person in Montrose

Colorado. This will be an in-person meeting with an option for remote participation. Contact Erik Knight

in the Grand Junction Area Office at (970) 248-0629 to get more information regarding this Operation 

Group meeting.

Navajo Reservoir 

On November 2nd the daily average release rate from Navajo Dam was 400 cfs while reservoir inflow was 

averaging 104 cfs. The water surface elevation was 6045.58 feet above sea level. At this elevation the live

storage is 1.12 maf (68 percent of live storage capacity) and the active storage is 494 maf (48 percent of

active storage capacity). Diversions to Cutter Reservoir for the Navajo Indian Irrigation Project (NIIP) and 

the Navajo Gallup Water Supply Project (NGWSP) have ceased for the year. Due to stream flows below

minimum bypass, 0 cfs is being diverted to the San Juan-Chama Project (SJC) above Navajo Reservoir. 

NIIP has diverted 190 kaf and SJC has diverted 142 kaf since January 1st of this year. 

Releases from Navajo Dam are made for authorized purposes of the Navajo Unit and are pursuant to the

Record of Decision for the Navajo Reservoir Operations. Releases target the San Juan River Recovery 

Implementation Program's (SJRIP) recommended downstream baseflow range of 500 cfs to 1,000 cfs

through the critical habitat reach of the San Juan River (Farmington, NM to Lake Powell).

Preliminary modified unregulated inflow (MUI) into Navajo in October was 12.3 kaf (32 percent of

average). The release averaged 520 cfs and totaled 32.0 kaf, which was 93 percent of average for the

month. Navajo had a net storage change of -24.5 kaf in October.

The most probable MUI forecast for November, December, and January is 17 kaf (64 percent of average),

17 kaf (82 percent of average), and 18 kaf (90 percent of average), respectively. 
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Reclamation conducts Public Operations Meetings three times per year to gather input for determining

upcoming operations for Navajo Reservoir. Input from individuals, organizations, and agencies along with

other factors such as weather, water rights, endangered species requirements, flood control, hydro power,

recreation, fish and wildlife management, and reservoir levels, will be considered in the development of

these reservoir operation plans. In addition, the meetings are used to coordinate activities and exchange

information among agencies, water users, and other interested parties concerning the San Juan River and 

Navajo Reservoir. The next meeting will be held on Tuesday, January 16th 2024 at 1:00 PM. This meeting is

open to the public, and will be held at the Farmington Civic Center, 200 West Arrington, in Farmington,

New Mexico (subject to change based on guidance at the time). The meeting will also have a virtual 

option.

Glen Canyon Dam / Lake Powell 

Current Status 

The unregulated inflow volume to Lake Powell during October was 324 kaf (72 percent of average). The

release volume from Glen Canyon Dam in October was 500 kaf. The end of October elevation and storage 

of Lake Powell were 3,572.71 feet (127 feet from full pool) and 8.72 maf (37 percent of live capacity),

respectively. 

Current Operations 

The August 2023 24-Month study projects the January 1, 2023, Lake Powell elevation to be less than 3,575 

feet and at or above 3,525 feet and the Lake Mead elevation to be at or above 1,025 feet. Consistent with

Section 6.C.1 of the Interim Guidelines the operational tier for Lake Powell in water year 2024 is the MidElevation Release Tier and the water year release volume from Lake Powell is 7.48 maf. 

November release volume will be 500,000 acre-feet and hourly releases will fluctuate from a low of

approximately 5,280 cubic feet per second (cfs) during the early morning hours to a high of 9,790 cfs

during the afternoon and evening hours. The anticipated monthly release volume for December is

anticipated to be 600,000 acre-feet and hourly releases will fluctuate from a low of approximately 6,157 

cubic feet per second (cfs) during the early morning hours to a high of 11,558 cfs during the afternoon

and evening hours on the weekdays, the Sunday minimum will be 5,022 cfs. This will be confirmed toward 

the end of November. 

In addition to daily scheduled fluctuations for power generation, the instantaneous releases from Glen

Canyon Dam may also fluctuate to provide 40 megawatts (MW) of system regulation. These

instantaneous release adjustments stabilize the electrical generation and transmission system and 

translate to a range of about 1,300 cfs above or below the hourly scheduled release rate. Under normal

system conditions, fluctuations for regulation are typically short lived and generally balance out over the

hour with minimal or no noticeable impacts on downstream river flow conditions.

Releases from Glen Canyon Dam can also fluctuate beyond scheduled releases when called upon to

respond to unscheduled power outages or power system emergencies. Depending on the severity of the

system emergency, the response from Glen Canyon Dam can be significant, within the full range of the

operating capacity of the power plant for as long as is necessary to maintain balance in the transmission

system. Glen Canyon Dam currently maintains 30 MW (approximately 1,300 cfs) of generation capacity in
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reserve in order to respond to a system emergency even when generation rates are already high. System

emergencies occur infrequently and typically require small responses from Glen Canyon Dam. However,

these responses can have a noticeable impact on the river downstream of Glen Canyon Dam.

Inflow Forecasts and Model Projections

The forecast for water year 2024 unregulated inflow to Lake Powell, issued on November 1, 2023, by the

Colorado Basin River Forecast Center, projects that the most probable (median) unregulated inflow

volume in water year 2024 will be 8.62 maf (90 percent of average). 

In addition to the November 2023 24-Month Study based on the Most Probable inflow scenario, and in

accordance with the Upper Basin Drought Response Operations Agreement (DROA), Reclamation has

conducted model runs in November to determine a possible range of reservoir elevations. The November

2023 24-Month Study probable most and minimum and the October 2023 maximum probable inflow

scenarios were used to determine the range of probable outcomes. The probable minimum and probable 

maximum model runs are conducted simultaneously in January, April, August, and October, or when

necessary to incorporate changing conditions. The probable minimum inflow scenario reflects a dry

hydrologic condition which statistically would be exceeded 90 percent of the time. The most probable

inflow scenario reflects a median hydrologic condition which statistically would be exceeded 50 percent of

the time. The probable maximum inflow scenario reflects a wet hydrologic condition which statistically

would be exceeded 10 percent of the time. There is approximately an 80 percent probability that a future

elevation will fall inside the range of the minimum and maximum inflow scenarios. Additionally, there are 

possible inflow scenarios that would result in reservoir elevations falling outside the ranges indicated in

these reports. 

The DROA coordination will continue until either (i) the minimum probable projected elevation remains 

above 3,525 feet for 24 months or (ii) the process moves to the next step when the most probable

projected elevation indicates Powell elevations below 3,525 feet and a Drought Response Operations Plan

is developed. This current Plan is described above and available for review here:

https://www.usbr.gov/dcp/droa.html. 

The November forecast for WY 2024 ranges from a minimum probable of 5.57 maf (58% of average) to a 

forecasted November 24-Month Study maximum probable of 15.42 maf (163 percent of average). There

is a 10 percent chance that inflows could be higher than the current maximum probable forecast and a 10 

percent chance that inflows could be lower than the minimum probable forecast.

Based on the current forecast for water year 2024 of 8.62 maf unregulated, the November 24-Month 

Study projects Lake Powell elevation will end calendar year 2024 near 3579.55 feet with approximately 

9.26 maf in storage (40 percent of capacity). Note that projections of elevation and storage for calendar

year 2024 have significant uncertainty at this point in the season. Projections of end of calendar year

2024 elevation using the November minimum and October maximum inflow forecast results are 3,543.88 

feet and 3,657.44 feet, respectively. The annual release volume from Lake Powell during water year 2024 

is 7.48 maf under the Mid-Elevation Release Tier as determined under Section 6.C.1 of the Interim

Guidelines as determined by the Department of the Interior as described above. 
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Upper Colorado River Basin Hydrology 

Upper Colorado River Basin regularly experiences significant year to year hydrologic variability. The 30-

year average was updated in October 2022 from 1981 through 2010 to 1991 through 2020. Shifting the

period of record decreased the average unregulated inflow 1.20 maf. The period 2000-2022 is the lowest

23-year period since the closure of Glen Canyon Dam in 1963, with an average unregulated inflow of 8.29

maf, or 93 percent of the 30-year average (1991-2020). (For comparison, the 1991-2020 total water year

average is 9.60 maf.) The unregulated inflow during the 2000-2022 period has ranged from a low of 2.64 

maf (28 percent of average) in water year 2002 to a high of 15.97 maf (166 percent of average) in water

year 2011. In water year 2021 unregulated inflow volume to Lake Powell was 3.50 maf (36 percent of

average), the second driest year on record above 2002. Under the current most probable forecast, the

total water year 2024 unregulated inflow to Lake Powell is projected to be 8.62 maf (90 percent of

average).

At the beginning of water year 2024, total system storage in the Colorado River Basin was 25.27 maf (43 

percent of 58.48 maf total system capacity). This is an increase of 5.72 maf over the total storage at the

beginning of water year 2023 when total system storage was 19.55 maf (33 percent of capacity). Since the

beginning of water year 2000, total Colorado Basin storage has experienced year to year increases and

decreases in response to wet and dry hydrology, ranging from a high of 94 percent of capacity at the

beginning of 2000 to the beginning of water year 2023 with 19.55 maf (33 percent of capacity). Based on

current inflow forecasts, the current projected end of water year 2024 total Colorado Basin reservoir 

storage is approximately 25.13 maf (43.0 percent of total system capacity). The actual end of water year

2024 system storage may vary from this projection, primarily due to uncertainty regarding this season’s

runoff and reservoir inflow.