Difference between revisions of "GCDAMP- HFE 2016"

Latest revision as of 14:38, 2 July 2020

High Flow Experiment- 2016

2016 High Flow Experiment Snapshot

• The 2016 HFE represents the 4th controlled high flow release conducted under the HFE Protocol.
• A preliminary analysis of these images indicates that sandbar size increased at 55% of sites, remained unchanged and 30% of sites, and decreased at 15% of sites, a response similar to those observed during each of the 2012-2014 HFEs.
• Before and after images from the November 2016 HFE from each of the 45 sandbar sites monitored with remotely deployed digital cameras are available here.

Sediment Conditions

Paria River gage at Lees Ferry

• Paria input (Jul 1 - Nov 6): 844,748
• Accumulated in Upper Marble Canyon (Jul 1 - Nov 6, lower bound) = 373,000
• Accumulated in Lower Marble Canyon (Jul 1 - Nov 6, lower bound) = 72,000
• Available for HFE: 373,000 + 72,000 = 445,000

Upper Marble Canyon

• Paria input (Nov 7 - 12): 1,000
• Evacuated from Upper Marble Canyon (Nov 7 - 12, lower bound) = -492,000
• Evacuated from Lower Marble Canyon (Nov 7 - 12, lower bound) = -184,000
• Left over in Marble Canyon after HFE (Nov 7 - 12): 445,000 + 1,000 - 492,000 - 184,000 = -230,000

Lower Marble Canyon

• Paria input (Dec 1 to Apr 1): 160,000
• Evacuated from Upper Marble Canyon (Dec 1 to Apr 1, lower bound) = -241,000
• Evacuated from Lower Marble Canyon (Dec 1 to Apr 1, lower bound) = -81,000
• Available for spring HFE: -241,000 - 81,000 = -322,000

HFE Details

Schedule & Duration

• Nov. 7 - 6 a.m. begin upramp to powerplant capacity ( ~21,000 cfs)
• Nov. 7 - 10:00 a.m. open bypass tubes, reach full bypass at 12:00 p.m.
• Nov. 11 - 12:00 p.m. end of bypass
• Nov. 12 - 3:00 a.m. end of HFE
• Total duration: 5 days & 5 hours (96 hours at peak release)

Ramp Rates

• Ramp up: 4,000 cfs/hr from 6,500 - 21,000 cfs, then 3,750 cfs/hr to peak (36,000 cfs)
• Ramp down: 1,875 cfs/hr from 36,000 - 21,000 cfs, then 1,500 cfs/hr to 9,000 cfs

HFE Release Details

• Maximum total release: 36,000 cfs
• Powerplant capacity: 21,000 cfs
• River outlet tubes: 15,000 cfs
• Hydropower generation units available: 6
• River outlet tubes: 4

Releases and Lake Elevation

• Releases will range from 6,500 - 9,000 cfs prior to and after the HFE
• Lake elevation is projected to decrease by approximately 2.5 feet during the 5-day period
• Estimated acre feet of water bypassed during HFE: 125 kaf
• November volume = 745 kaf

Costs

• Estimated costs to hydropower: $1.4 million
• Actual costs to hydropower: 1.15 million
• Direct expenses for removal of concession assets: TBD

SUPPORTING DOCUMENTS

• Financial Analysis of Experimental Releases Conducted at Glen Canyon Dam during Water Year 2017
• Fall 2016 HFE Planning
• Technical Team Memo: Final Recommendation to Implement a Fall 2016 High Flow Experiment at Glen Canyon Dam
• Leadership Team Memo: Approval of Recommendation for Experimental High-Flow release from Glen Canyon Dam, November 7-12, 2016

COMPLIANCE

• HFE Protocol

CONCERNS

• Grand Canyon Private Boater's Association (GCPBA) letter requesting slower downramp rates following the Fall 2016 High flow experiment.
• Angler's concerns regarding a Fall 2016 High flow experiment on foodbase, trout condition, and disbursement of green sunfish. Also, noted that a comprehensive written three year review of the first three HFEs has not been provided yet.
• Re-emergence of green sunfish in the -12 Mile Slough.
• Increase in brown trout spawning and the increased prevalence of adult brown trout in the Lees Ferry reach since the beginning of the HFE Protocol.

ADDITIONAL

• Downstream Flow Arrival Timing Map
• Glen Canyon Dam Possible HFE Release Pattern