Grand Canyon, Colorado River Flows - October, November, December
10/5/16 Update: GCPBA has learned from Paul Davidson at Glen Canyon Dam that a meeting to discuss planning for a High-Flow Experiment was going to happen today, 10/5.
He said, "It looks like a High Flow will happen." It is "probable and favorable" that Glen Canyon Dam will release a river flow of about 35,000 cfs for 4 days during November.
Many 1,000's of metric tons of sediment have washed down the Paria River into the Colorado, which needs to be redistributed down the river corridor.
A high flow will likely occur starting November 7 or 14 and will last for 5-1/2 days total. The flow would rise to about a 35,000 cfs peak, stay there for 96 hours, then come back down to the level it was at before ramp-up.
The ranger at Lees Ferry, as part of the river orientation talk, will inform boaters who will be on their river trips during the high flow of the high flow details.
Campers at riverside should be very aware of rising and falling water at the beaches where their boats are tied up for the nights.
Boaters should be aware that some rapids will show major differences from what they may have seen before, when the flows were half, or less than half, of what they could encounter during a few days of November.
September 28, 2016 Update:
The release volume from Glen Canyon Dam for October, 2016, will be 600,000 acre-feet. Hourly releases during October, 2016, are anticipated to fluctuate between approximately 7,000 cfs in the nighttime and 13,000 cfs in the daytime.
The anticipated release volume for November, 2016, is 600,000 acre-feet. However, the release volume in November may be modified depending on the size and duration of a High-Flow Experiment, as described in the Environmental Assessment for Development and Implementation of a Protocol for High-Flow Experimental Releases from Glen Canyon Dam, Arizona, 2011 through 2020.
A fall HFE can be triggered any time during October-November. Our best preliminary data and model runs indicate we now have enough sediment input from the Paria River to trigger an HFE at Glen Canyon Dam under the HFE Protocol. The HFE Technical Team will be meeting to begin planning for a possible HFE and reviewing the status of resources and potential resource impacts.
At this time we do not have a set date for a fall HFE. Further data collection, modeling, and analysis prior to the end of October may modify the expected duration and/or magnitude of a HFE. A final determination on the timing, magnitude and duration of a potential fall 2016 HFE will likely be made near the end of October.
The anticipated release volume for December, 2016, is 900,000 acre-feet. This will be confirmed in a subsequent notification toward the end of October.
Paul Davidson, Hydraulic Engineer, Glen Canyon Dam
Bureau of Reclamation 125 S. State St. Salt Lake City, UT 84138 Ph: 801-524-3642
Posted by GCPBA, Grand Canyon Private Boaters Association | To ensure the ability for all to obtain an opportunity to experience a float trip through the Grand Canyon while protecting the resource.