GCDAMP Technical 

Management Work Group

Basin Hydrology, Operations and 

Water Quality

October 11, 2022

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

Reservoir

Percent 

Current 

Live 

Storage

Current 

Live 

Storage

(maf)

Live 

Storage 

Capacity 

(maf)

Elevation

(feet)

Fontenelle 81 0.27 0.33 6,497.47

Flaming 

Gorge 73 2.67 3.67 6,012.75

Blue Mesa 35 0.29 0.83 7,445.66

Navajo 53 0.87 1.65 6,020.85 

Lake Powell 25 5.85 23.31 3,530.21

UC System 

Storage 34 10.08 29.79 -

Total System 

Storage 33 19.55 58.48 -

2
Water Year Snowpack and Precipitation1,2,3

as of October 11, 2022

SWE peaked at 90% of the 

peak seasonal median on 

March 24, 2022.

Colorado Basin River Forecast Center

Lake Powell Unregulated 

Inflow maf % of 

Average

April – July 2022

(observed) 3.75 59%

Water Year 2022

(preliminary observed) 6.08 63%

Colorado River Basin 

above Lake Powell

Water Year 2022

Precipitation 

(observed)

101%

Water Year 2023

Precipitation

(year-to-date)

91% of average

Current Snowpack 

NA% of median

1Percent of normal precipitation is based on an arithmetic mean, or average; percent of normal snowpack is based on the median value for a given date. 2Statistics are based on the 30-year period of record from 1991-2020. 3Precipitation values may vary significantly from week-to-week this early in the water year. 3
Most Probable – Observed and October Final

Water Years 2022 and 2023

April – July 2022

Observed Unregulated Inflow

Reservoir Inflow

(kaf)

Percent 

of Avg1

Fontenelle 456 62

Flaming Gorge 552 57

Blue Mesa 431 68

Navajo 381 60

Powell 3,750 59

Water Year 2022

Observed Unregulated Inflow

Reservoir Inflow

(kaf)

Percent 

of Avg1

Fontenelle 744 69

Flaming Gorge 900 64

Blue Mesa 639 71

Navajo 574 63

Powell 6,084 63

Water Year 2023

Unregulated Inflow Forecast

as of October 1, 2022

Reservoir Inflow

(kaf)

Percent 

of Avg1

Fontenelle 930 87

Flaming Gorge 1,215 86

Blue Mesa 820 91

Navajo 790 87

Powell 8,100 84

4

1

Averages are based on the 1991 through 2020 period of record.
5
Upper Basin DROA Initial Unit Drought Response 

Releases started in July 2021 and finished October 2021

• January 2022 minimum probable 

model elevations were below 

3,525 feet within 24 month

• Continued drought conditions 

exacerbated already parched soil 

moisture conditions

• May 2022 most probable 

elevations were below 3,525 feet

• Continued below average inflows 

decreased available water in the 

San Juan Basin

6
Upper Basin Drought Response Actions

• The Bureau of Reclamation announced on May 3, 2022, two separate urgent drought response 

actions that will help prop up Lake Powell by nearly 1 million acre-feet (maf) of water over the next 

12 months (May 2022 through April 2023). To protect Lake Powell, more water will flow into the lake 

from upstream reservoirs and less water will be released downstream:

• Under a Drought Contingency Plan adopted in 2022, approximately 500 thousand acre-feet (kaf) of water 

will come from Flaming Gorge Reservoir, located approximately 455 river miles upstream of Lake Powell 

(2022 Plan). 

• For more information: https://www.usbr.gov/uc/DocLibrary/Plans/20220429-2022DroughtResponseOperationsPlan-ApprovalMemo508-DOI.pdf. 

• Another 480 kaf will be left in Lake Powell by reducing Glen Canyon Dam’s annual release volume from 

7.48 maf to 7.00 maf (GC Operational Adjustment), in accordance with Sections 6 and 7.D of the 2007 

Interim Guidelines.

• For more information: https://www.usbr.gov/uc/DocLibrary/Plans/20220503-2022DROA-GlenCanyonDamOperationsDecisionLetter508-DOI.pdf

7
Drought Response Operations Agreement (DROA)

8

DROA Volumes Released1

Reservoir

2021 

DROA 

Volume

(kaf)

2022 

DROA 

Volume

(kaf)

Total 

DROA 

Volume 

(kaf)

Flaming Gorge 125 500 625

Blue Mesa 36 0 36

Navajo 0 0 0

Volume in 

Powell 161 500 661

1DROA operational year is from May through April. 

Historical Future

Flaming Gorge 2022 Plan Daily Releases
9
10

August and 

September 24-

Month Study 

Projections

Upper Colorado Basin 

Region Operations
Lake Powell & Lake Mead Operational Table

Lake Powell Operational Tier Determination Run (aka “Exhibit Run”) with an 8.23 maf Release1,2

3,505.66 ft

Jan 1, 2023 

Projection

11

1 Lake Powell and Lake Mead operational tier determinations are based on August 2021 24-Month Study projections will be documented in the draft 2023 AOP.

2 The operating determination for WY 2023 is based on a projected elevation “as if” the 0.48 maf were delivered to Lake Mead with a Glen Canyon Dam release pattern 

of 8.23 maf.

1,047.61 ft

Jan 1, 2023 

Projection
Upper Basin Reservoir Operations 

in Water Year 2023

12

• 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’s projected end of calendar year (CY) 2022 “tier determination” elevation in the August 2022 24-Month 

Study determines Lake Powell’s operating tier in CY 2023

• Lake Powell will operate in the Lower Elevation Balancing Tier where Lake Powell and Lake Mead will balance contents with Glen Canyon 

Dam release volumes no less than 7.0 maf and no more than 9.5 maf

• Consistent with the provisions of the 2007 Interim Guidelines, and to preserve the benefits to Glen Canyon Dam 

facilities from 2022 Operations into 2023 and 2024, Reclamation will consult with the Basin States on monthly and 

annual operations. 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.

• The Glen Canyon Dam annual release has initially been set to 7.00 maf, and in April 2023 Reclamation will evaluate hydrologic conditions

to determine if balancing releases may be appropriate under the conditions established in the 2007 Interim Guidelines; 

• Balancing releases will be limited (with a minimum of 7.00 maf) to protect Lake Powell from declining below elevation 3,525 feet at the 

end of December 2023;

• Balancing releases will take into account operational neutrality of the 0.480 maf that was retained in Lake Powell under the May 2022 

action1. Any Lake Powell balancing release volume will be calculated as if the 0.480 maf had been delivered to Lake Mead 

in WY 2022; and

• The modeling approach for WY 2023 will apply to 2024.
Powell Release Scenario

13
14
Most Probable End of CY 2022 Projection: 

3,522.79 feet (23% full)

Min/Max Range: 3,521.18 to 3,524.72 feet

Most Probable End of CY 2023 Projection: 

3,525.22 feet (24% full)

Min/Max Range: 3,484.66 to 3,586.78 feet

16
Comparison of Current (August 2022) and Last Published (May 2022) 

CRMMS-ESP 5-Year Projections

Chance of Lake Powell Falling Below Critical Reservoir Elevations in any Month of the Water Year (WY)

- Run WY 2023 WY 2024 WY 2025 WY 2026 WY 20271

Lake Powell less than 3,525 feet

May 2022 90% 50% 37% 30% 23%

August 2022 100% 50% 37% 30% 30%

Difference 10% 0% 0% 0% 7%

Lake Powell less than 3,490 feet 

(minimum power pool)

May 2022 3% 23% 17% 23% 13%

August 2022 10% 30% 20% 17% 13%

Difference 7% 7% 3% -6% 0%

Lake Powell less than 3,375 feet

(dead pool = 3,370 feet)

May 2022 0% 0% 0% 0% 0%

August 2022 0% 0% 0% 0% 0%

Difference 0% 0% 0% 0% 0%

17

All results are computed based on projected physical elevations for Lake Powell.

1 For modeling purposes, simulated years beyond 2026 assume a continuation of the 2007 Interim Guidelines, the 2019 Colorado River Basin 

Drought Contingency Plans, and Minute 323, including the Binational Water Scarcity Contingency Plan. Except for certain provisions related to 

ICS recovery and Upper Basin demand management, operations under these agreements are in effect through 2026. Reclamation anticipates 

beginning a process in early 2023 to develop operations for post-2026, and the modeling assumptions described here are subject to change 

for the analysis to be used in that process.
Most Probable End of CY 2022 Projection: 

1,043.14 feet (28% full)

Min/Max Range: 1,043.01 to 1,047.39 feet

Most Probable End of CY 2023 Projection: 

1,023.90 feet (23% full)

Min/Max Range: 1,014.03 to 1,058.63 feet

19
Comparison of Current (August 2022) and Last Published (May 2022) 

CRMMS-ESP 5-Year Projections

Chance of Lake Mead Falling Below Critical Reservoir Elevations in any Month of the Calendar Year

- Run 2023 2024 2025 2026 20271

Lake Mead less than 1,020 feet

May 2022 40% 50% 47% 50% 53%

August 2022 47% 57% 57% 60% 57%

Difference 7% 7% 10% 10% 4%

Lake Mead less than 1,000 feet

May 2022 0% 13% 20% 20% 13%

August 2022 0% 23% 20% 20% 17%

Difference 0% 10% 0% 0% 4%

Lake Mead less than 950 feet 

(minimum power pool)

May 2022 0% 0% 0% 3% 3%

August 2022 0% 0% 0% 7% 3%

Difference 0% 0% 0% 4% 0%

Lake Mead less than 900 feet 

(dead pool = 895 feet)

May 2022 0% 0% 0% 0% 0%

August 2022 0% 0% 0% 0% 0%

Difference 0% 0% 0% 0% 0%

20

All results are computed based on projected physical elevations for Lake Mead.

1 For modeling purposes, simulated years beyond 2026 assume a continuation of the 2007 Interim Guidelines, the 2019 Colorado River Basin 

Drought Contingency Plans, and Minute 323, including the Binational Water Scarcity Contingency Plan. Except for certain provisions related to 

ICS recovery and Upper Basin demand management, operations under these agreements are in effect through 2026. Reclamation anticipates 

beginning a process in early 2023 to develop operations for post-2026, and the modeling assumptions described here are subject to change 

for the analysis to be used in that process.
Upper Colorado Basin

Hydropower 

Maintenance

21
Glen Canyon Dam Power Plant Unit Outage Schedule for WY2023

22

24 
Water Quality

25
10

10

10

10 10

15

15

15

15 15 20

20 20 20 20

25

25

25

25

25

10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220

Lake Powell Sept 2022 Temperature

3200

3250

3300

3350

3400

3450

3500

8

10

12

14

16

18

20

22

24

26

elevation, ft

Deg C

Penstock

River Outlet

Km from GCD
1 1

1 1

1

1

1

1

1

1 1

1

2

2

2

2

2

2

2

2

2 2

2

2

2

4

4

4

4

4

4

4 4

4

4 4

4

6

6

6

6

6

10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220

Lake Powell Sept 2022 Dissolved Oxygen

3200

3250

3300

3350

3400

3450

3500

0

1

2

3

4

5

6

7

elevation, ft

mg/L

River Outlet

Penstock

Km from GCD



Questions?

32