Bighorn Basin Operations and Water Supply Meeting April 14, 2016

Boysen Dam And

Buffalo Bill Dam Operations

Presenter

Presentation Notes

Carlie, introduction The Wyoming Area Offices manages dams and reservoirs on three main rivers across Wyoming; The Shoshone River, the Wind River, and the North Platte River. Today, we will be looking at our operations on the Shoshone River and Buffalo Bill Reservoir. The presentation will start by looking at our operations from 2015 before we see the current water supply outlook and how that effects our plans for 2016. Finally, I will update you on some of the OM&R projects going on at Buffalo Bill Reservoir.

Current Reservoir Conditions As of April 11, 2016

Reservoir Content % of Full % of Avg Boysen 590,882 80% 109% Bull Lake 71,924 47% 93% Buffalo Bill 440,857 68% 106%

SNOW WATER EQUIVALENT - % MEDIAN DRAINAGE BASIN 4/11/2016 4/4/2016 3/28/2016 4/11/2015 4/11/2014 4/11/2013

SNAKE RIVER 93 98 100 83 143 92

MADISON 86 87 93 62 120 94

YELLOWSTONE 88 94 91 86 152 93

WIND RIVER 95 105 90 73 125 80

BIGHORN BASIN 80 89 80 80 149 90

SHOSHONE RIVER 96 94 95 77 153 89

POWDER 81 92 81 80 156 98

TONGUE 66 76 63 75 140 82

BELLE FOURCHE 35 64 53 0 181 74

CHEYENNE 14 58 60 0 135 81

UPPER N. PLATTE 97 101 100 62 125 77

SWEETWATER 88 95 85 54 108 67

LOWER N. PLATTE 108 120 100 50 125 66 LARAMIE 108 117 117 67 136 78

S. PLATTE 126 133 127 69 142 80

LITTLE SNAKE RIVER 92 101 101 46 123 70

UPPER GREEN 95 101 99 89 157 82

LOWER GREEN 98 110 104 54 126 90

UPPER BEAR 84 99 96 52 113 79

Weighted State Average 85 97 90 61 139 83

Red = down blue = up green = even * data is suspect

National Weather Service Three Month Outlook

Temperature Outlook - April, May, June 2016 Precipitation Outlook - April, May, June 2016

Bighorn Basin Water Supply Forecast April 1 Forecast of April – July Snowmelt Runoff

Boysen Forecast - April

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2013 2014 2015 2016 AVG.

A-J Inflow (acre-feet)

2013 216,300

2014 694,500

2015 749,700

2016 ??

30-year avg. 548,300

2016 Forecast 350 350 350 550

Boysen Forecast – Full Year

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2013 2014 2015 2016 AVG.

A-J Inflow (acre-feet)

2013 216,300

2014 694,500

2015 749,700

2016 ??

30-year avg. 548,300

2016 Forecast 350 350 350 550

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Apr-16 May-16 Jun-16 Jul-16 Aug-16 Sep-164705.0

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Water Year 2016

Elev

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BOYSEN RESERVOIR OPERATIONS Water Year 2016 Projection

Inflow Outflow Elevation

Top of Joint Use Pool = 4725.0 ft

Approximate Powerplant Capacity = 2,300 cfs

Buffalo Bill Forecast - April

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2013 2014 2015 2016 AVG.

A-J Inflow (acre-feet)

2013 576,500

2014 1,062,400

2015 696,400

2016 ??

30-year avg. 686,300

2016 Forecast 620 620 600 620

Buffalo Bill Forecast – Full Year

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2013 2014 2015 2016 AVG.

A-J Inflow (acre-feet)

2013 576,500

2014 1,062,400

2015 696,400

2016 ??

30-year avg. 686,300

2016 Forecast 620 620 600 620

Buffalo Bill Reservoir Operations

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Water Year 2016

Inflow Outflow Elevation

Top of Conservation Elev. 5393.5 feet

Approximate Powerplant Capacity = 1,500 cfs

Yellowtail Dam and Bighorn Lake Operations Review

Recap of Fall and Winter 2015/2016

Total April-October Gain = 239,300 acre-feet Forecasted November-March Gain = 258,200 acre-feet Upstream Reservoir Fall & Winter Releases = Boysen = 850 cfs Buffalo Bill = 205 cfs End-of-October Storage = 952,900 acre-feet Projected End-of-March Target Elevation = 3617 (807,900

acre-feet) Calculated Fall & Winter Release for Yellowtail: River = 2,450 cfs

Recap of Fall and Winter 2015/2016

Nov-Mar Gains: Forecast on November 1, 2015: 258.2 kaf (101% of Avg) Actual November-March Gains: 279.0 kaf (109% of Avg)

Total Nov-Mar Inflow: Forecast on November 1, 2015: 575.1 kaf (100% of Avg) Actual November-March Inflows: 590.3 kaf (103% of Avg)

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Bighorn Lake Operations 2016

2016

Top of Joint Use

Most Probable

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Inflow

Releases

Snowpack and

Precipitation

March 1, 2016

April 13, 2016

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Mountain Snowpack on January 1

Average 2016 2015

SWE = 70% of Average April-July Forecast = 711.3 kaf (64%)

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Mountain Snowpack on February 1

Average 2016 2015

SWE = 70% of Average April-July Forecast = 596.2 kaf (54%)

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Mountain Snowpack on March 1

Average 2016 2015

SWE = 75% of Average April-July Forecast = 625.7 kaf (56%)

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Mountain Snowpack on April 1

Average 2016 2015

SWE = 91% of Average April-July Forecast = 873.0 kaf (78%)

April – July Inflow Year Forecast

(kaf) Actual (kaf)

2016 873 ?

2015 676 1,543 Average 1114.3

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Mountain Snowpack on April 13

Average 2016 2015 2007

April – July Inflow

Year Actual (kaf)

2016 873? 2015 1,543 2007 613

Average 1,114

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Bighorn River Basin Precipitation

2016 Outlook

Bighorn Lake April – July Forecast

Most Probable Inflow 873,000 af or 78% of average

Minimum Probable Inflow 485,800 af or 44% of average

Maximum Probable Inflow 1,304,300 af or 117% of average

April – July Inflow

Year Forecast (kaf)

Actual (kaf)

2016 873 ?

2015 676 1,543

2014 1,967 1,725

2013 661 628

2012 1,064 693

2011 1,400 2,572

Average 1,114

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2016

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Inflo

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Bighorn Lake April through July Inflow Period of Record 1967-2015

Average = 1,114.3 kaf 873.0 kaf

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April 1 Rule Curve

Rule Curve Top of Joint Use Inflow River Release

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Apr-16 May-16 Jun-16 Jul-16 Aug-16 Sep-16 Oct-16 Nov-16 Dec-16 Jan-17 Feb-17 Mar-17 Apr-17

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Most Probable Inflow Operations

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Apr-16 May-16 Jun-16 Jul-16 Aug-16 Sep-16 Oct-16 Nov-16 Dec-16 Jan-17 Feb-17 Mar-17 Apr-17

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Most and Minimum Probable Inflow Operations

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Apr-16 May-16 Jun-16 Jul-16 Aug-16 Sep-16 Oct-16 Nov-16 Dec-16 Jan-17 Feb-17 Mar-17

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Apr-16 May-16 Jun-16 Jul-16 Aug-16 Sep-16 Oct-16 Nov-16 Dec-16 Jan-17 Feb-17 Mar-17 Apr-17

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Most and Maximum Probable Inflow Operations

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Apr-16 May-16 Jun-16 Jul-16 Aug-16 Sep-16 Oct-16 Nov-16 Dec-16 Jan-17 Feb-17 Mar-17

Riv

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(cfs

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Apr-16 May-16 Jun-16 Jul-16 Aug-16 Sep-16 Oct-16 Nov-16 Dec-16 Jan-17 Feb-17 Mar-17 Apr-17

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Most, Minimum, and Maximum Probable Inflow Operations

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low

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Questions and Feedback

The information presented at this meeting can be found on the Montana Area Office website at:

www.usbr.gov/gp/mtao/yellowtail/index.html