Glen Canyon Adaptive 

Management Program 

Basin Hydrology and Operations 

February 21, 2024 

1 
Upper Basin Storage (as of February 26, 2024) 

Reservoir 

Percent 

Current 

Live 

Storage 

Current 

Live 

Storage 

(maf) 

Live 

Storage 

Capacity 

(maf) 

Elevation 

(feet) 

Fontenelle 39 0.13 0.33 6,474.33 

Flaming 

Gorge 85 3.11 3.67 6,025.73 

Blue Mesa 68 0.56 0.83 7,487.82 

Navajo 65 1.08 1.65 6,041.76 

Lake Powell 34 7.96 23.31 3,562.40 

UC System 

Storage 43 12.97 29.93 

Total System 

Storage 43 24.91 58.48 

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Weather Prediction Center and Climate 

Prediction Center Precipitation Forecasts 

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Upper Colorado SWE – New Web Links! 

https://nwcc-apps.sc.egov.usda.gov/awdb/basin- https://nwcc-apps.sc.egov.usda.gov/awdb/basinplots/POR/WTEQ/assocHUC2/14_Upper_Colorado_Region.html plots/Proj/WTEQ/assocHUC2/14_Upper_Colorado_Region.html 

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Most Probable February Forecast

Water Year 2024 

April – July 2024 

Forecasted Unregulated Inflow 

as of February 5, 2024 

Reservoir Inflow 

(kaf) 

Change 

from 

Jan 

Percent 

of Avg1 

Fontenelle 540 +5 73 

Flaming Gorge 680 +5 70 

Blue Mesa 560 +70 88 

Navajo 390 +15 62 

Powell 4,700 +500 74 

February Midmonth = 4,900 kaf +200 (77%) 

Water Year 2024 

Unregulated Inflow Forecast 

as of February 5, 2024 

Reservoir Inflow 

(kaf) 

Change 

from 

Jan 

Percent 

of Avg1 

Fontenelle 870 -8 81 

Flaming Gorge 1,148 -7 81 

Blue Mesa 799 +71 88 

Navajo 553 +17 61 

Powell 7,356 +438 77 

February Midmonth = 7,576 kaf +220 (79%) 

1

Averages are based on the 1991 through 2020 period of record. 

6 
 

 

Upper Colorado Observed Inflows 

 

Observed WY2020 = 5.85 maf (61% of avg) 

Feb Midmonth WY2024 = 7.58 maf (79% of avg) Feb Midmonth WY2020 = 8.56 maf (89% of avg)* 

https://waterwatch.usgs.gov/index.php https://waterwatch.usgs.gov/index.php 

*WY2020 averages are based on the 1991 through 2020 period of record. The February 2020 percent of average based on the 1981 through 2010 

period of record is 79% of average. 7 
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Upper Colorado Basin 

Hydrology and Operations 

Projections Based on January 

and February 2024 24-

Month Study 

9 
 

 

 

 

 

 

Upper Basin Reservoir Operations 

Water Years 2024 and 2025 

• Lake Powell will be operated consistent with the 2007 Interim Guidelines, the Upper Basin 

Drought Response Operations Agreement and Upper Basin Records of Decision 

• Lake Powell WY 2024 will operate in the Mid-Elevation Release Tier where Lake Powell will 

release 7.48 maf 

• Reclamation will also ensure all appropriate consultation with Basin Tribes, the Republic of 

Mexico, other federal agencies, water users and non-governmental organizations with respect 

to implementation of these monthly and annual operations. 

10 
 

 

 

DROA Recovery - BM 

• December 2023 recovery amount of 13 kaf 

• Incremental Recovery at Blue Mesa 

COMPLETED by midnight 12/29. 

• Icing target ACHIEVED at 7490.05’ on 

midnight 12/31. 

11 
 

 

 

DROA Recovery - FG 

• December 2023 recovery amount of 50.3 kaf 

• January 2024 recovery amount ~50 kaf 

• Projected February volume ~45 kaf 

• Projected to achieve incremental recovery in 

February 2024 and the May 1 Drawdown Target 

of 6,027 (mod-dry target) 

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Drought Response Operations Agreement (DROA) 

Completed DROA Volumes1,2 

Reservoir 

2021 

DROA 

Volume 

(kaf) 

2022 

DROA 

Volume 

(kaf) 

2023 

DROA 

Volume 

(kaf)4 

Total 

DROA 

Volume 

(kaf) 

Flaming 

Gorge 125 3283 -408 45 

Blue Mesa 36 0 -36 0 

Navajo 0 0 0 0 

Total DROA 

Volume 

(kaf) 

161 328 -444 45 

1

DROA operational year is from May through April. 

2Positive values indicate Drought Response Operations Releases and negative 

values indicate Drought Response Operations Recovery 

3 463 kaf of DROA releases prior to DROA release suspension on March 6, 2023. 

-135 kaf of DROA recovery from March 7, 2023 through April 30, 2023 

13 4DROA volumes through September 2023 
 

 

 

 

 

 

Reclamation Operational Modeling

Model Comparison 

Colorado River Mid-term Modeling System (CRMMS) 

24 CRSS -Month Study Mode 

(Manual Mode) 

Ensemble Mode 

(Rule-based Mode) 

Primary Use 

AOP tier determinations and 

projections of current 

conditions 

Risk-based operational planning 

and analysis 

Long-term planning, comparison of 

alternatives 

Simulated Reservoir 

Operations Operations input manually Rule-driven operations 

Probabilistic or 

Deterministic 

Deterministic – single 

hydrologic trace 

Deterministic OR 

Probabilistic 30 (or more) 

hydrologic traces 

Probabilistic – 100+ traces 

Time Horizon (years) 1 - 2 1 - 5 1 - 50 

Upper Basin Inflow Unregulated forecast, 1 trace Unregulated ESP forecast, 30 traces Natural flow; historical, paleo, or 

climate change hydrology 

Upper Basin Demands Implicit, in unregulated inflow forecast Explicit, 2016 UCRC assumptions 

Lower Basin Demands Official approved or operational Developed with LB users 

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Mead ESP

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Powell ESP 

Most Probable End of CY 2024 Projection: 

1,056.99 feet (31% full) 

Min/Max Range: 1,054.33 to 1,064.89 feet 

Most Probable End of CY 2025 Projection: 

1,050.64 feet (30% full) 

Min/Max Range: 1,039.21 to 1,072.08 feet 

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Upper Colorado Basin 

Hydropower

Maintenance 

17 
Glen Canyon Dam Power Plant Unit Outage Schedule for 2024 

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Glen Canyon Dam Power Plant Unit Outage Schedule for 2025 

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Questions? 

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