Aspinall Operations Meeti

April 28, 2016
SNOWPACK SUMMARY

89% of seasonal 
88% of seasonal 
84% of seasonal 
82% of seasonal 
RESERVOIR AND RIVER STAT
0

500

1000150020002500300035004000

12/1 12/16 12/31 1/15 1/30 2/14 2/29 3/15 3/30 4/14 

Average Daily Flow (cfs)

December 2015 - April 2016

BM Inflow Crystal Release Black Canyon Flow BM Cont
0

500

1000150020002500300035004000

Feb‐01 Feb‐08 Feb‐15 Feb‐22 Feb‐29 Mar‐07 Mar‐14 Mar‐21 Mar‐28 Apr‐04 Apr‐11 

Gunnison River Flows

Crystal Dam Gunnison R ‐ Black Canyon North Fork @ Confluence Gunniso

Baseflow Target

RUNOFF FORECASTS
610

640

620 580

530 515 515

755 785 770

710

650 640 635

0

100200300400500600700800900

1000110012001300140015001600

Jan 1st Feb 1st Feb 15th Mar 1st Mar 15th Apr 1st Apr 15th May 1st May 15th Jun 1st Jun 15th J

Apr - July Forecasted Inflow (1000 ac-ft)

Forecast Date

Aspinall Unit

Forecasted Unregulated Inflow

Blue Mesa Inflow Crystal Inflow

Bar labels are forecast

in 1000 ac-ft

1
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% 110% 120% 

Percent of 1981-2010 Average

Forecasted April-July Runoff

As of April 1st

Gunnison River - near Grand Jct 1,150,000

Ridgway Reservoir Inflow 88,000

North Fork Gunnison River - near Somerset 225,000

Paonia Reservoir Inflow (Mar-Jun) 70,000

Lake Fork Gunnison River - at Gateview 115,000

Tomichi Creek - at Gunnison 57,000

Blue Mesa Reservoir Inflow 515,000Gunnison River - near Gunnison 265,000

East River - at Almont 128,000

Taylor Park Reservoir Inflow 79,000

Site 

runo

in a
Year Type

Blue Mesa Forecasted Desired Peak at

Whitewater

Duration of Half Bank

(8,070 cfs)

Duration 

(up to 1

April‐July Inflow

Af cfs Days D

DRY < 381,000 900 0 

MOD DRY 381,000 to 516,000 2,600 to 8,070 0 

AVG DRY 516,001 to 709,000 8,070 10 

AVG WET 709,001 to 831,000 8,070 to 14,350 20 

MOD WET 831,001 to 1,123,000 14,350 40 

WET >1,123,000 14,350 60 

Spring Peak & Duration Targets

Based on Hydrologic Year Type

Mid‐Apr

515,000
PROJECTED OPERATIONS
3197 cfs

Apr 15 Forecast

515 KAF

Projected Black Cany

of 5000– 5500 

to meet ROD ta
0

2000400060008000

10000120001400016000

200 300 400 500 600 700 800 900 1000 1100 1200 

Peak Q (cfs)

Forecast BM Apr-Jul Inflow (thousand af)

Peak Flow and Duration Day Targets at Whitew

DRY

MOD WET

AVGWET

AVGDRY

MODDRY

Apr‐July Forecast Half bank Duration Pe

(1000 AF) (days @ 8,070 cfs) (day

<381 0 

381‐516 0 516‐709 10 709‐831 20 

831‐1123 40 

>1123 60 

8029 cfs
0

1234567

4/16 4/21 4/26 5/1 5/6 5/11 5/16 5/21 5/26 5/31 6/

North Fork of the Gunnison River

Peak Flow Timing at Somerset (1934‐2015)
North Fork of the Gunnison River

Forecasted Streamflows

Peak Flow

Forecast

2100 cfs
Projection of Flows in the Gunnison River

while meeting the Aspinall ROD Flow Targets

0

100020003000400050006000700080009000

10000

5/1 5/6 5/11 5/16 5/21 5/26 5/31 6/5 6/10 6/15 6/20 6/25 6/30 7/

Flow (cfs)

Gunnison River Flows

Mod Dry Year Scenario

Black Canyon Delta Whitewater North Fork

BC peak WW peak Days > 14Days > 80

Ramp up = Ramp down 
0

100020003000400050006000700080009000

10000

5/1 5/6 5/11 5/16 5/21 5/26 5/31 6/5 6/10 6/15 6/20 6/25 6/30 7/

Flow (cfs)

Gunnison River Flows

Avg Dry Year Scenario

Black Canyon Delta Whitewater North Fork

BC peak WW peak Days > 143Days > 80

Projection of Flows in the Gunnison River

while meeting the Aspinall ROD Flow Targets

Ramp up = Ramp down 
Baseflow Targets
100

200300400500600700800

Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oc

1000 Acre-feet

Blue Mesa Content

End of Month

Mid-April Forecast = 515,000 AF

Fill to 731 Kaf

Current = 568 Kaf

Maximum 
0

250500750

100012501500

Dec Jan Feb Mar Apr May Jun Jul Aug Sep O

Flow (cfs)

Gunnison River - Black Canyon

Monthly Average Flow
WEATHER OUTLOOK
Precipitation Forecast Apr 27 – May 3
Precipitation Outlook May 2 ‐ 6
Precipitation Outlook May 4 ‐ 10