Basin Hydrology, 

Water Years 2018-2019 

Operations 

Glen Canyon Technical Work Gro

January 25, 2018
Snow Conditions

2

As of 1-23-2018 

SWE is 66% of median

36% of total averag

seasonal accumulati

And 61% through the s

accumulation seaso
88%

68%

57%

74%

51%

1 Percent of average based on 

https://www.usbr.gov/uc/water/basin/index.html

Reservoir

WY

Forec

(KAF

Fontenelle 780 

Flaming Gorge 1,00

Blue Mesa 420 

Navajo 295 

Powell 3,90

Upper Basin Storage

April to July 2018 Fore

Issued January 16

3

Basin Storage

As of 

01/22/2018
4

Mid-month: 3.9 maf (55%)
5

Lake Powell 2018 Operating TieUpper Elevation Balancing

• Tier was set in August 2017

– Start with 8.23 maf release

• Use April 24-Month Study 

projections of end of water year storage to potentially adjust

1. Stay with 8.23 maf2. Balancing: 8.23 - 9.0 maf3. Equalization: > 8.23 maf
No April 

Adjustment

April adjus

Equalization 

6

April adjustment to 

Balancing releases
Lake Powell 2018 Operating Tier Sce

Based on January 2018 modeling 

Inflow 

Scenario

Operating Tier

Release Volume

Minimum

Probable

Upper Elevation Balancing

9.0 maf

Most

Probable

Upper Elevation Balancing

9.0 maf

Maximum 

Probable

Upper Elevation Balancing

9.0 maf

7
LTEMP Monthly Release Volum

Month 7.00 7.48 8.23 9.00 9.50 10.50 11.00 12.00 OCT 480 480 640 640 640 640 640 640 6NOV 500 500 640 640 640 640 640 640 6DEC 600 600 720 720 720 720 720 720 7JAN 660 720 760 860 920 1040 1100 1230 1FEB 590 640 680 750 810 920 970 1080 1MAR 620 675 710 800 860 970 1030 1150 1APR 550 600 640 710 760 870 920 1020 1MAY 550 600 630 710 760 860 910 1020 1JUN 580 630 660 750 800 910 960 1060 1JUL 650 710 750 850 900 1020 1080 1200 1AUG 700 760 800 900 970 1090 1160 1280 1SEP 520 565 600 670 720 820 870 960 1
Unit 

Number

Oct 

2017

Nov 

2017

Dec 

2017

Jan 

2018

Feb 

2018

Mar 

2018

Apr 

2018

May 

2018

Jun 

2018

Jul 

2018

12345678

Units 

Available 6 6/4 4/6 6 4/6 5/6 5/6 6/7 8 8 

Capacity 

(cfs) 21,000 13,200 13,200 20,600 13,100 13,100 13,100 20,600 28,100 28.10

Capacity 

(kaf/month) 1,290 970 1,170 1,260 790 1,140 1,190 1,440 1,670 1,730 

Max (kaf) 1 667 630 740 860 730 800 705 705 760 860 

Most (kaf) 2 640 630 740 860 730 800 705 705 760 860 

Min (kaf) 1 630 630 740 860 730 800 705 705 760 860 

9

Glen Canyon Power Plant Planned Unit Outage Schedule for Water 

1 Projected release, based on Jan 2018 Min and Max Probable 

Inflow Projections and 24-Month Study model runs

2 Projected release, based on Jan 2018 Most Probable Inflow 

Projections and 24-Month Study model runs

(up
10
11

Water Year 2018 projections

Most: 9.0 maf release

MIN: 9.0 maf release 

MAX: 9.0 maf release 

End of CY 2017 Elevation:

3622.85 feet (58% full) End of CY 2018 Projection:

3599.85 feet (48% full)

Min/Max Range: 3582 to 3626 feet

Water Year 

Most: 9

MIN: 8.

MAX: 11
Most Probable End of CY 2018 

Projection: 1,079.5 feet (38% full)

Min/Max Range: 1,076 to 1,083 feet

Most Probable 

Projection: 1,07

Min/Max Range: 

End of CY 2017 Elevation: 

1,082.5 feet (39% full)

12
Water Year 2019

Projected Operations

13
LTEMP Monthly Release Volumes 2

Month 7.00 7.48 8.23 9.00 9.50 10.50 11.00 12.00 OCT 480 480 640 640 640 640 640 640 6NOV 500 500 640 640 640 640 640 640 6DEC 600 600 720 720 720 720 720 720 7JAN 660 720 760 860 920 1040 1100 1230 1FEB 590 640 680 750 810 920 970 1080 1MAR 620 675 710 800 860 970 1030 1150 1APR 550 600 640 710 760 870 920 1020 1MAY 550 600 630 710 760 860 910 1020 1JUN 580 630 660 750 800 910 960 1060 1JUL 650 710 750 850 900 1020 1080 1200 1AUG 700 760 800 900 970 1090 1160 1280 1SEP 520 565 600 670 720 820 870 960 1

MIN & MOST

MAX
Unit 

Number

Oct 

2018

Nov 

2018

Dec 

2018

Jan 

2019

Feb 

2019

Mar 

2019

Apr 

2019

May 

2019

Jun 

2019

Jul 

2019

12345678

Units 

Available 6 8 6 6 6 4/6 6 7 8 8 

Capacity 

(cfs) 20,600 28,100 20,500 20,500 20,500 13,100 20,600 24,400 28,100 28.10

Capacity 

(kaf/month) 1,340 1,670 1,290 1,260 1,140 1,220 1,280 1,590 1,670 1,730 

Max (kaf) 1 640 640 720 1,170 1,030 1,100 980 970 1,020 1,150 

Most (kaf) 2 640 640 720 860 750 800 710 710 750 850 

Min (kaf) 1 640 640 720 860 750 800 710 710 750 850 

15

Glen Canyon Power Plant Planned Unit Outage Schedule for Water 

1 Projected release, based on Jan 2018 Min and Max Probable 

Inflow Projections and 24-Month Study model runs

2 Projected release, based on Jan 2018 Most Probable Inflow 

Projections and 24-Month Study model runs

(up

Possible HFE

Questions?

Paul Davidson

801-524-3642

PDavidson@usbr.gov

Hydraulic Engineer, Glen Canyon

Reclamation, Upper Colorado Region

Resource Management Division

Water Resources Group
2018 Hydrograph (9.0 MAF)

Month LTEMP Release, (kaf) BOR/WAPA Planne

(kaf)

OCT 640 640

NOV 640 630

DEC 720 740

JAN 860 860

FEB 750 730

MAR 800 800

APR 710 705

MAY 710 705

JUN 750 760

JUL 850 860

AUG 900 900

SEP 670 670

TOTALS