# Grand Canyon River Flows - October, November, & December



## GCPBA (Oct 22, 2009)

*Grand Canyon, Colorado River Flows - October, November, & December*

This is an October 12, 2017 update from Paul Davidson at Glen Canyon Dam.

There is a special note regarding this year's High-Flow Experiment. It is not going to happen. He reports:

High-Flow Experiments (HFE) below Glen Canyon Dam are driven by weather, sediment inputs, and other resource conditions, in accordance with the Glen Canyon Dam Long-Term Experimental and Management Plan Record of Decision (LTEMP).

When sediment conditions during the summer and fall meet specific thresholds as described in the LTEMP HFE Protocol, a fall HFE can occur. Fall HFEs can be scheduled to occur anytime during the months of October and November. In order to facilitate advance planning for a potential HFE this fall, the HFE technical team determined that October 9th was the latest date for which sediment inputs could be considered for a potential HFE this fall. Grand Canyon Monitoring and Research Center (GCMRC) scientists and Reclamation modelers considered cumulative sediment inputs from July 1 through midnight October 9th. Based on these data it has been determined that there is not sufficient sediment to support implementing a high flow experiment (HFE) at Glen Canyon Dam during the fall 2017 planning window; therefore an HFE will not be tested this fall. 

Regarding the regular river flow report - The release volume from Glen Canyon Dam for October, 2017, will be 667,000 acre-feet. Hourly releases during October, 2017, are anticipated to fluctuate between approximately 8,300 cfs in the nighttime and 14,000 cfs in the daytime.

The anticipated release volume for November, 2017, is 630,000 acre-feet with daily fluctuations between approximately 8,000 cfs in the nighttime and 13,700 cfs in the daytime.

The expected release volume for December, 2017, is 740,000 acre-feet. This will be confirmed in a subsequent notification toward the end of November.

Paul Davidson, Hydraulic Engineer, Glen Canyon Dam

_Bureau of Reclamation 125 S. State St. Salt Lake City, UT 84138_ _Ph: 801-524-3642_


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## David L (Feb 13, 2004)

Thank you for the short report. I have some friends down there soon who were hoping for a high flow.


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