Glen Canyon Dam Technical 

Working Group

Basin Hydrology, Operations and 

Water Quality

January 13, 2022

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

Reservoir

Percent 

Current 

Live 

Storage

Current 

Live 

Storage

(maf)

Live 

Storage 

Capacity 

(maf)

Elevation

(feet)

Fontenelle 58 0.19 0.33 6,486.33 

Flaming 

Gorge 77 2.90 3.75 6,017.67

Blue Mesa 28 0.23 0.83 7,434.91 

Navajo 51 0.87 1.70 6,020.19

Lake Powell 27 6.58 24.32 3,535.25 

UC System 

Storage 35 10.89 30.93

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Water Year 2022 (October - December) Monthly Precipitation Summary

October precipitation was well above average

across much of the region including southwest

Wyoming, most of Utah, and northern Arizona.

Western Colorado had near average October 

precipitation while southern Arizona hadbelow 

average precipitation during the month.

November’s weather pattern was mostly very 

warm and dry with much below average 

monthly precipitation across most of the region.

November precipitation fell in the bottom five at 

numerous SNOTEL stations across Utah, 

southwest Colorado, and centralArizona.

The weather pattern shifted during the second week 

of December towards colder and wetter conditions 

and featured multiple storm systems that brought 

widespread precipitation to most of the region during 

the last three weeks of the month.

The majority of SNOTEL sites across Utah and 

western Colorado and a few sites across central 

Arizona reported December precipitation values that 

ranked in the wettest five on record.
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.
Fall Model Soil Moisture Conditions: 2020 vs. 2021

Soil Moisture - Fall (November 15)

Modeled, %Change 

(2021-2020)

This is an experimental CBRFC soil moisture graphic.

Utah & Arizona model soil moisture 

conditions improved more compared to 

southwest Wyoming & western Colorado.

Prepared by NOAA, Colorado Basin River Forecast Center 

Salt Lake City, Utah, www.cbrfc.noaa.gov
SWE as of 01/12/22

6 https://www.nrcs.usda.gov/Internet/WCIS/AWS_PLOTS/basinCharts/POR/WTEQ/assocHUC2/14_Upper_Colorado_Region.html
7 https://www.nrcs.usda.gov/Internet/WCIS/AWS_PLOTS/basinCharts/Proj/WTEQ/stdHUC2/14_Upper_Colorado_Region.html
NOAA Precipitation Outlook Comparison

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Increase from December 2021

Min Probable increase 2.61 maf

Most Probable increase 2.50 maf

Max Probable increase 2.22 maf

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Most Probable December Forecast

Water Year 2022

Water Year 2022

Forecasted Unregulated Inflow

as of January 5, 2022

Reservoir

Unregulated 

Inflow

(kaf)

1991-2020

Percent 

of Avg

Fontenelle 942 88

Flaming Gorge 1,216 86

Blue Mesa 880 97

Navajo 725 80

Powell 8,767 91

April – July 2022

Forecasted Unregulated Inflow as of January 5, 2022

Reservoir

Unregulated 

Inflow

(kaf)

1991-2020

Percent 

of Avg

Fontenelle 650 88

Flaming Gorge 840 87

Blue Mesa 650 102

Navajo 550 88

Powell 6,300 99

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Current Upper Colorado Drought Response Activities

Drought Response Operations Agreement

• Effective May 2019

• Continues through 2026 (except 

recovery)

• 2021 DROA release volumes of 161 kaf 

completed in October 2021

• Glen Canyon Dam release adjustments 

under LTEMP flexibility beginning in 

January 2022

Drought Response Operations Plan

• Scheduled to be finalized in April 

2022 

• Draft framework document 

circulating for review

• Webinar in late January to be 

followed by comment period

• 2022 operational plans based on 

actual hydrology to be developed 

February through April

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Upper Colorado Basin

Projected Operations 

for Water Year 2022 

Based on December 

2021 Modeling

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Most Probable December Forecast

Water Year 2022

Water Year 2022

Forecasted Unregulated Inflow

as of December 1, 2021

Reservoir

Unregulated 

Inflow

(kaf)

1991-2020

Percent 

of Avg

Fontenelle 865 81

Flaming Gorge 1,096 78

Blue Mesa 689 76

Navajo 572 63

Powell 6,272 65

April – July 2022

Forecasted Unregulated Inflow as of December 1, 2021

Reservoir

Unregulated 

Inflow

(kaf)

1991-2020

Percent 

of Avg

Fontenelle 580 79

Flaming Gorge 720 75

Blue Mesa 480 75

Navajo 400 64

Powell 4,120 64

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Lake Powell & Lake Mead Operational Table

Operating Determinations for Water Year/Calendar Year 2022

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.

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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 35 (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

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Lake Mead End of Month Elevations 

Projections from the December 2021 24-Month Study Inflow Scenarios

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25 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

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Glen Canyon Dam Power Plant Unit Outage Schedule for 2022

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Glen Canyon Dam Power Plant Unit Outage Schedule for 2023

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Water Quality

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Spring 2022 HFE Modeling

GCD Adjusted LTEMP Pattern (-103 kton) GCD Standard LTEMP Pattern (-143 ktons)

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Temperature Profile of Lake Powell near Glen Canyon Dam

1/7/2022

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Cross Sectional Temperature Profile of Lake Powell

1/7/2022

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Lake Powell Dec 2021 Temperature

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elevation, ft

Deg C

Penstock

River Outlet
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Lake Powell Dec 2021 Dissolved Oxygen

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elevation, ft

DO mg/L

Penstock

River Outlet
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Lake Powell Dec 2021 TDS

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elevation, ft

mg/L

Penstock

River Outlet

Km from Dam
Thank you, TWG, BOR, and Lake Powell!
Questions?

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