Aspinall Unit operations update: Current forecast for inflow into Blue Mesa = 71% of avg

April 15, 2015

Blue Mesa Reservoir

Blue Mesa Reservoir


From email from Reclamation (Erik Knight):

Releases from Crystal Dam will be increased from 1050 cfs to 1150 cfs on Wednesday, April 15th at 9:00 AM. This release increase is in response to an increase in diversion to the Gunnison Tunnel. The current forecast for April-July unregulated inflow to Blue Mesa Reservoir is 480,000 acre-feet which is 71% of average.

Flows in the lower Gunnison River are currently above the baseflow target of 1050 cfs. River flows are expected to stay above the baseflow target for the foreseeable future.

Pursuant to the Aspinall Unit Operations Record of Decision (ROD), the baseflow target in the lower Gunnison River, as measured at the Whitewater gage, is 1050 cfs for April.

Currently, diversions into the Gunnison Tunnel are 700 cfs and flows in the Gunnison River through the Black Canyon are around 350 cfs. After this release change Gunnison Tunnel diversions will be around 800 cfs and flows in the Gunnison River through the Black Canyon should be around 350 cfs. Current flow information is obtained from provisional data that may undergo revision subsequent to review.


Aspinall Unit operations update

April 8, 2015

Crystal dam spilling May 2009

Crystal dam spilling May 2009


From email from Reclamation (Erik Knight):

Releases from Crystal Dam will be increased from 600 cfs to 750 cfs on Wednesday, April 8th at 8:00 AM. This release increase is in response to an increase in diversion to the Gunnison Tunnel. The current forecast for April-July unregulated inflow to Blue Mesa Reservoir is 480,000 acre-feet which is 71% of average.

Flows in the lower Gunnison River are currently above the baseflow target of 1050 cfs. River flows are expected to stay above the baseflow target for the foreseeable future.

Pursuant to the Aspinall Unit Operations Record of Decision (ROD), the baseflow target in the lower Gunnison River, as measured at the Whitewater gage, is 1050 cfs for April.

Currently, diversions into the Gunnison Tunnel are 300 cfs and flows in the Gunnison River through the Black Canyon are around 300 cfs. After this release change Gunnison Tunnel diversions will be around 400 cfs and flows in the Gunnison River through the Black Canyon should be around 350 cfs. Current flow information is obtained from provisional data that may undergo revision subsequent to review.

More Aspinall Unit coverage here.


Aspinall Unit update: The Gunnison Tunnel to turn on Tuesday

March 30, 2015
Gunnison Tunnel via the National Park Service

Gunnison Tunnel via the National Park Service

From email from Reclamation (Erik Knight):

Releases from Crystal Dam will be increased from 500 cfs to 600 cfs on Tuesday, March 31st at 9:00 AM. This release increase is in response to the start of diversions into the Gunnison Tunnel. On Tuesday morning, the Gunnison Tunnel will begin diverting 200 cfs. The current forecast for April-July unregulated inflow to Blue Mesa Reservoir is 590,000 acre-feet which is 87% of average.

Flows in the lower Gunnison River are currently above the baseflow target of 1050 cfs. River flows are expected to stay above the baseflow target for the foreseeable future.

Pursuant to the Aspinall Unit Operations Record of Decision (ROD), the baseflow target in the lower Gunnison River, as measured at the Whitewater gage, is 1050 cfs for March and April.

Currently, diversions into the Gunnison Tunnel are zero and flows in the Gunnison River through the Black Canyon are around 500 cfs. After this release change Gunnison Tunnel diversions will be around 200 cfs and flows in the Gunnison River through the Black Canyon should be around 400 cfs. Current flow information is obtained from provisional data that may undergo revision subsequent to review.

More Aspinall Unit coverage here.


Aspinall Unit forecast for spring operations

March 24, 2015
Aspinall Unit

Aspinall Unit

From email from Reclamation (Erik Knight):

The March 15th forecast for the April – July unregulated inflow volume to Blue Mesa Reservoir is 590,000 acre-feet. This is 87% of the 30 year average. Snowpack in the Gunnison Basin is currently at 78% of average. Blue Mesa Reservoir current content is 551,800 acre-feet which is 67% of full. Current elevation is 7486.2 ft. Maximum content at Blue Mesa Reservoir is 829,500 acre-feet at an elevation of 7519.4 ft.

Black Canyon Water Right
The peak flow and shoulder flow components of the Black Canyon Water Right will be determined by the May 1 forecast of the April – July unregulated inflow volume to Blue Mesa Reservoir. If the May 1 forecast is equal to the current forecast of 590,000 acre-feet of runoff volume, the peak flow target will be equal to 4,340 cfs for a duration of 24 hours. The shoulder flow target will be 381 cfs, for the period between May 1 and July 25. The point of measurement of flows to satisfy the Black Canyon Water Right is the Gunnison River below Gunnison Tunnel streamgage at the upstream boundary of Black Canyon of the Gunnison National Park.

Aspinall Unit Operations ROD
Pursuant to the Aspinall Unit Operations Record of Decision (ROD), the peak flow and duration flow targets in the lower Gunnison River, as measured at the Whitewater gage, will be determined by the forecast of the April – July unregulated inflow volume to Blue Mesa Reservoir and the hydrologic year type. At the time of the spring operation, if the forecast is equal to the current forecast of 590,000 acre-feet of runoff volume, the hydrologic year type will be set as Average Dry. Under an Average Dry year the peak flow target will be 8,070 cfs and the duration target at this flow will be 10 days.

Projected Spring Operations
During spring operations, releases from the Aspinall Unit will be made in an attempt to match the peak flow of the North Fork of the Gunnison River to maximize the potential of meeting the desired peak at the Whitewater gage, while simultaneously meeting the Black Canyon Water Right peak flow amount. The magnitude of release necessary to meet the desired peak at the Whitewater gage will be dependent on the flow contribution from the North Fork of the Gunnison River and other tributaries downstream from the Aspinall Unit. Current projections for spring peak operations show that flows in the Gunnison River through the Black Canyon could be in the 5,000 to 5,500 cfs range for 10 days in order to achieve the desired peak flow and duration at Whitewater. If actual flows on the North Fork of the Gunnison River are less than currently projected, flows through the Black Canyon could be even higher. With this runoff forecast and corresponding downstream targets, Blue Mesa Reservoir is currently projected to fill to an elevation of around 7508.2 feet with an approximate peak content of 730,000 acre-feet.

Downstream flow targets and the projected spring operations to meet them will change with revisions to the forecast and are highly dependent on tributary flows throughout the Gunnison Basin.

More Aspinall Unite coverage here.


The Aspinall Unit operations meeting minutes are hot off the presses #ColoradoRiver

February 25, 2015

Aspinall Unit dams

Aspinall Unit dams


Click here to read the minutes from the recent Aspinall Unit Operations meeting.


Aspinall Unit operations update: Releases from Crystal Dam to decrease today

February 5, 2015
Aspinall Unit

Aspinall Unit

From email from Reclamation (Erik Knight):

Releases from Crystal Dam will be decreased from 800 cfs to 600 cfs on Thursday, February 5th at 9:00 AM. This release decrease is in response to the declining runoff forecast for Blue Mesa Reservoir. The current forecast for April-July unregulated inflow to Blue Mesa Reservoir is 620,000 acre-feet which is 92% of average.

Flows in the lower Gunnison River are currently above the baseflow target of 1050 cfs. River flows are expected to stay above the baseflow target for the foreseeable future.

Pursuant to the Aspinall Unit Operations Record of Decision (ROD), the baseflow target in the lower Gunnison River, as measured at the Whitewater gage, is 1050 cfs for February.

Currently, diversions into the Gunnison Tunnel are zero and flows in the Gunnison River through the Black Canyon are around 850 cfs. After this release change Gunnison Tunnel diversions will still be zero and flows in the Gunnison River through the Black Canyon should be around 650 cfs. Current flow information is obtained from provisional data that may undergo revision subsequent to review.


Aspinall Unit operations update

January 23, 2015


From email from Reclamation (Erik Knight):

Releases from Crystal Dam will be decreased from 1100 cfs to 800 cfs on the morning of Monday, January 26th. This release decrease is in response to the declining runoff forecast for Blue Mesa Reservoir. The current forecast for April-July unregulated inflow to Blue Mesa Reservoir is 660,000 acre-feet which is 98% of average.

Flows in the lower Gunnison River are currently above the baseflow target of 1050 cfs. River flows are expected to stay above the baseflow target for the foreseeable future.

Pursuant to the Aspinall Unit Operations Record of Decision (ROD), the baseflow target in the lower Gunnison River, as measured at the Whitewater gage, is 1050 cfs for January through March.

Currently, diversions into the Gunnison Tunnel are zero and flows in the Gunnison River through the Black Canyon are around 1150 cfs. After this release change Gunnison Tunnel diversions will still be zero and flows in the Gunnison River through the Black Canyon should be around 850 cfs. Current flow information is obtained from provisional data that may undergo revision subsequent to review.

More Aspinall Unit coverage here.


Follow

Get every new post delivered to your Inbox.

Join 1,162 other followers

%d bloggers like this: