Update on Hydrology, 

Operations and Water Quality 

Conditions

GCAMP Technical Working Group

April 13, 2021
Upper Basin Storage (as of April 11, 2021)

Reservoir

Percent 

Current 

Live 

Storage

Current 

Live 

Storage

(maf)

Live 

Storage 

Capacity 

(maf)

Elevation

(feet)

Fontenelle 38 0.13 0.33 6473.12

Flaming 

Gorge 85 3.17 3.75 6,025.37

Blue Mesa 48 0.39 0.83 7,464.23

Navajo 62 1.05 1.70 6,033.73

Lake Powell 36 8.73 24.32 3,565.23 

UC System 

Storage 44 13.59 31.09

2
Seasonal and Monthly Precipitation

3
Seasonal Snow Conditions and Basin SWE

4
Current Snow Water Equivalent (as of April 11, 2021)

5
Most Probable Spring and WY2021 Forecast

April – July 2021

Forecasted Unregulated Inflow

as of April 2, 2021

Reservoir

Unregulated 

Inflow

(kaf)

Percent of 

Average1

Fontenelle 430 59

Flaming Gorge 430 54

Blue Mesa 440 65

Navajo 395 54

Powell 3,200 45

Water Year 2021

Forecasted Unregulated Inflow

as of April 5, 2021

Reservoir

Unregulated 

Inflow

(kaf)

Percent of 

Average1

Fontenelle 691 64

Flaming Gorge 833 57

Blue Mesa 645 68

Navajo 538 50

Powell 4,897 45

6 1 Percent of average based on the period of record from 1981-2010.
7
Upper Colorado Basin

Projected Operations 

for Water Year 2021 

Based on March 2021 

Modeling

8
March Most Probable Spring and WY2021 Forecast

April – July 2021

Forecasted Unregulated Inflow

as of March 2, 2021

Reservoir

Unregulated 

Inflow

(kaf)

Percent of 

Average1

Fontenelle 480 66

Flaming Gorge 555 57

Blue Mesa 460 68

Navajo 415 56

Powell 3,400 47

Water Year 2021

Forecasted Unregulated Inflow

as of March 2, 2021

Reservoir

Unregulated 

Inflow

(kaf)

Percent of 

Average1

Fontenelle 755 70

Flaming Gorge 865 59

Blue Mesa 669 70

Navajo 567 53

Powell 5,130 47

9 1 Percent of average based on the period of record from 1981-2010.
Drought Response Operations Agreement (DROA)

• Formal notification that the January 2021 Minimum Probable 24 Month Study (24-MS) run 

projected Powell to fall below 3,525 feet in 2022 was provided pursuant to the DROA.

• February and March Minimum Probable 24-MS continued to indicate elevations below 3525 feet in 2022.

• These minimum projections do not initiate immediate operational changes to Reclamation facilities. 

• These minimum projections do initiate enhanced monitoring and coordination under the DROA. 

• These minimum projections do initiate monthly analysis of min/most/max with the parties specified 

in the DROA. 

• The DROA enhanced monitoring and coordination will continue until either:

• (i) The minimum probable projected elevation remains above 3525' for 24 months; or

• (ii) the process moves to the next step when the Most Probable 24-MS projects Powell elevations below 3,525 

feet and a specific Drought Response Operations Plan is developed. (Section II.A.4.b)

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11
12
13
14
15
16
Glen Canyon Power Plant Planned Unit Outage Schedule for Water Year 2021

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Glen Canyon Power Plant Planned Unit Outage Schedule for Water Year 2022

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19
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Water Quality

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Temperature Profile of Lake Powell near Glen Canyon Dam

Penstock

3/14/2021

23
Cross Sectional Temperature Profile of Lake Powell

3/16/2021

24
25
>16°C HBC Spawn

>12°C HBC Growth

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7

7

7

7

7 7

7

9

9

9

9

9 9

10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230

Lake Powell March 2021 Temperature, High discharge 20013 CFS

3200

3250

3300

3350

3400

3450

3500

3550

6.4

6.8

7.2

7.6

8

8.4

8.8

9.2

9.6

10

10.4

10.8

elevation, ft

Penstock Deg C

Km from dam

4

4

6

6

6

6

8

8 8

8

8

8

8

8

8

8 8

10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230

Lake Powell March 2021 Dissolved Oxygen, high discharge 20,013 cfs

3200

3250

3300

3350

3400

3450

3500

3550

3

3.5

4

4.5

5

5.5

6

6.5

7

7.5

8

8.5

9

9.5

10

elevation, ft

Penstock mg/L

Km from Dam

7

7

7

7

7

7

7

9

9

9

9

9 9

10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230

Lake Powell March 2021 Temperature, normal discharge 11689 CFS

3200

3250

3300

3350

3400

3450

3500

3550

6.4

6.8

7.2

7.6

8

8.4

8.8

9.2

9.6

10

10.4

10.8

Penstock

elevation, ft

Deg C

Km from Dam

4

4

6 6

6

6

8

8 8

8

8

8

8

8

8

8

8

10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230

Lake Powell Dissolved Oxygen March 2021 normal discharge 11,689 cfs 

3200

3250

3300

3350

3400

3450

3500

3550

3

3.5

4

4.5

5

5.5

6

6.5

7

7.5

8

8.5

9

9.5

10

Penstock

elevation, ft

mg/L

Km from Dam

4

4

4

4

4

4

4 4

4

4

4

4

4

4

4

4

4

4

4

4

4

4

8

8

8

8

8

8

8

8

8

8

8

8

8

8

8

8

8

8

8

8

8

8

8 8

8

8 8

8

Lake Powell Wahweap Forebay Nov 2011 - March 2021 Dissolved Oxygen

3200

3250

3300

3350

3400

3450

3500

3550

3600

1

2

3

4

5

6

7

8

9

10

11

12

13

14

Penstock

elevation, ft

mg/L

1/1/2012 1/1/2013 1/1/2014 1/1/2015 1/1/2016 1/1/2017 1/1/2018 1/1/2019 1/1/2020 1/1/2021

River Outlet
Questions/Discussion

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