Basin Hydrology, Reservo

Operations

Glen Canyon Technical Work Gro

April 20-21, 2016
Snow Conditions

2

As of 4/18/2017 

SWE is 106% of median
3

83%

74%

48% 91%

42%

1 percent of average based on 

http://www.usbr.gov/uc/water/basin/tc_cr.html

Reservoir

A-J 

Forec

(KAF

Fontenelle 1,68

Flaming Gorge 2,26

Blue Mesa 930 

Navajo 760 

Powell 9,30

Basin Storage

As of 

4/17/2017

Upper Basin Storage

2017 April to 

Inflow Forec

Issued April 4, 
4

Mid-month: 8.8 maf (123%)

* Water Year 2017 forecast: 13.47 maf (124%)
5

Lake Powell 2017 Operating TieUpper Elevation Balancing

• Tier was set in August 2016

– 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
August

determination

April 

determination
Water Year 2017 Operations: April 2017 24-Mon

Upper Elevation Balancing

With an 8.23maf releasWY2017, September 30projected elevations arPowell: 3646.82 (i.e, abMead: 1072.07 (i.e, beTherefore, Powell’s Apis to Balancing, with remore than 9.0 maf and 8.23 maf in the Water Y

April 2017 24-Month Study EXHIBIT run

7
8
9
10

End of CY 2017 Projection

(Range 3,619 to 3,660 

Water Year 2017 projections

Most: 9.0 maf release

Max: 9.0 maf release 

Min: 9.0 maf release 

Water Yea

Most: 11

Max: 14

Min: 9.

Current conditions (as of 4/19)

Elevation: 3,600.2 feet

Content: 11.8 maf, 48% Full
End of CY 2017 Projection: 

1,079.8 feet (38% full)

Range: 1,079.2 to 1,080.4 feet 

End of CY 20

1,102.3 fe

Range: 1,075.
Unit 

Number

Oct 

2016

Nov 

2016

Dec 

2016

Jan

2017

Feb

2017

Mar 

2017

Apr 

2017

May 

2017

Jun 

2017

Jul 

2017

12345678

Units 

Available 6666 5 5 6 7 77

Capacity 

(cfs) 21,000 21,000 19,700 19,750 16,100 15,900 19,600 23,400 23,400 23,40

Capacity 

(kaf/month) 1,310 1,280 1,180 1,270 920 1,070 1,250 1,400 1,390 1,440 

Max (kaf) 1 601 750 898 880 711 720 620 650 750 850 

Most (kaf) 2 601 750 898 880 711 720 620 650 750 850 

Min (kaf) 1 601 750 898 880 711 720 620 650 750 850 

12

Glen Canyon Power Plant Planned Unit Outage Schedule for Water 

1 Projected release, based on Apr 2017 Min and Max Probable 

Inflow Projections and 24-Month Study model runs

2 Projected release, based on Apr 2017 Most Probable Inflow 

Projections and 24-Month Study model runs

(up
Reservoir Operations 

for Water Year 2018

13
2018 Projected Release Scenar

Based on April 2017 24-Month Study Inflow Scena

Powell Inflow 

Scenario

WY 2018

Release Projection

Probable 

Minimum

Upper Elevation Balancing Tie

w/ Projected April shift to Balancing

9.0 maf release

Most 

Probable

Upper Elevation Balancing Tie

w/ Projected April shift to Equalization

11.5 maf release

Probable 

Maximum

Equalization Tier 

14.4 maf release

14


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 5 7 7 7 5 5 5 6/8 8 8 

Capacity 

(cfs) 16,100 23,400 23,400 23,400 16,200 16,000 16,000 27,000 27,000 27,00

Capacity 

(kaf/month) 1,060 1,390 1,440 1,290 920 980 1,040 1,520 1,610 1,660 

Max (kaf) 1 640 640 720 1,520 1,340 1,420 1,260 1,260 1,320 1,490 

Most (kaf) 2 640 640 720 1,160 1,020 1080 966 956 1,000 1,140 

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

17

Glen Canyon Power Plant Planned Unit Outage Schedule for Water 

1 Projected release, based on Apr 2017 Min and Max Probable 

Inflow Projections and 24-Month Study model runs

2 Projected release, based on Apr 2017 Most Probable Inflow 

Projections and 24-Month Study model runs

(up
Questions?

Paul Davidson

801-524-3642

PDavidson@usbr.gov

Hydraulic Engineer, Glen Canyon

Reclamation, Upper Colorado Region

Resource Management Division

Water Resources Group
Paria Sand Load Dec 1 though Feb 13 Paria Sand Load July 1 though Feb 

Sediment Conditions As of 2-13-2015

Sediment Model RAs of 2-13-2015Have: ~18 ktonsNeed: several hundred k

(for the smallest H

19
If we end up with a 8.23 maf release instead of 9.

will need to reduce the remaining months by 7
Dave Trueman

dtrueman@usbr.gov

(801) 524-3759

Manager

Resource Management Division

Upper Colorado Region

Salt Lake City, UT

Objective: better preserve August 

and September sand inputs for 

potential HFE in November. 

Typical 

greatest 

21