Glen Canyon Dam Technical 

Working Group

Basin Hydrology, Operations and 

Water Quality

April 12, 2022

1
Upper Basin Storage (as of April 11, 2022)

Percent Current Live 

Current Live Storage Elevation Reservoir Live Storage Capacity (feet)

Storage (maf) (maf)

Fontenelle 46 0.16 0.33 6,479.37 

Flaming 78 2.93 3.75 6,018.71 Gorge

Blue Mesa 29 0.24 0.83 7,436.96 

Navajo 51 0.86 1.70 6,019.67

Lake Powell 24 5.79 24.32 3,522.84 

UC System 33 10.12 30.93 Storage

2
SWE as of 01/12/22

3 https://www.nrcs.usda.gov/Internet/WCIS/AWS_PLOTS/basinCharts/POR/WTEQ/assocHUC2/14_Upper_Colorado_Region.html
Fall Model Soil Moisture Conditions: 2020 vs. 2021

CBRFC model soil moisture 

conditions are improved from their 

record/near record dry levels a year

ago but remain below to well below 

normal across many of the major 

runoff producing areas, notably 

western Colorado.

The timing and magnitude of spring 

runoff is ultimately a result of snow 

conditions, spring weather, and 

antecedent soil moisture conditions. 

Basins with above average soil 

moisture conditions can be expected 

to experience more efficient runoff 

from rainfall or snowmelt while 

basins with below average soil 

moisture conditions can be expected 

to have lower runoff efficiency until 

soil moisture deficits are fulfilled
NOAA Precipitation Outlook Comparison

5
6
Most Probable April Forecast

Water Year 2022

April – July 2022

Forecasted Unregulated Inflow

as of April 4, 2022

Unregulated Percent Reservoir Inflow of Avg (kaf)

Fontenelle 435 59

Flaming Gorge 520 54

Blue Mesa 530 83

Navajo 390 62

Powell 4,100 64

Water Year 2022

Forecasted Unregulated Inflow

as of April 5, 2022

Unregulated Percent Reservoir Inflow of Avg (kaf)

Fontenelle 712 66

Flaming Gorge 855 61

Blue Mesa 755 83

Navajo 555 61

Powell 6,310 66

7 Averages are based on the 1991 through 2020 period of record. 
Current Upper Colorado Drought Response Activities

Drought Response Operations Agreement Drought Response Operations Plan

• Effective May 2019 • Scheduled to be finalized in May 

• Expires after 2026 (except recovery) 2022 after publication of the April 

24-Month Study

• 2021 DROA release volumes of 161 kaf 

completed in October 2021 • 2022 operational plans based on 

actual hydrology to be developed 

• Glen Canyon Dam release adjustments using April results under LTEMP flexibility beginning in 

January 2022

8
9 
Upper Colorado Basin

Projected Operations 

for Water Year 2022 

Based on March 2022 

Modeling

10
11
Most Probable March Forecast

Water Year 2022

April – July 2022

Forecasted Unregulated Inflow as of March 3, 2022

Unregulated 1991-2020

Reservoir Inflow Percent 

(kaf) of Avg

Fontenelle 450 61

Flaming Gorge 540 56

Blue Mesa 560 88

Navajo 455 72

Powell 4,400 69

12

Water Year 2022

Forecasted Unregulated Inflow

as of March 3, 2022

Unregulated 1991-2020

Reservoir Inflow Percent 

(kaf) of Avg

Fontenelle 726 68

Flaming Gorge 884 63

Blue Mesa 783 87

Navajo 614 67

Powell 6,583 69
Lake Powell & Lake Mead Operational Table

Operating Determinations for Water Year/Calendar Year 2022

3,535.40 ft

Jan 1, 2022 

Projection

1,065.85 ft

Jan 1, 2022 

Projection

1 Lake Powell and Lake Mead operating determinations are based on August 2021 24-Month Study projections consistent with the 2007 Interim Guidelines 

and 2019 Drought Contingency Plans. These determinations will be documented in the 2022 Annual Operating Plan for Colorado River Reservoirs.

13
14
15
Reclamation Operational Modeling

Model Comparison

Colorado River Mid-term Modeling System (CRMMS)

24-Month Study Mode CRSS

(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)

Upper Basin Inflow Unregulated forecast, 1 trace Unregulated ESP forecast, 35 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

1 - 2 1 - 5 1 - 50

16
17
18
19

Most Probable End of CY 2022 Projection: 

1,049.37 feet (29% full)

Min/Max Range: 1,047.10 to 1,052.33 feet Most Probable End of CY 2023 Projection: 

1,035.63 feet (26% full)

Min/Max Range: 1,020.63 to 1,046.72 feet
20 CRMMS 2-Year Probabilistic Projections are available online at: https://www.usbr.gov/lc/region/g4000/riverops/crmms-2year-projections.html
Upper Colorado Basin

Hydropower 

Maintenance

21
Glen Canyon Dam Power Plant Unit Outage Schedule for 2022

22
Glen Canyon Dam Power Plant Unit Outage Schedule for 2023

23
24
25
26
Questions?

27