# Grand Canyon, Colorado River Flows - August and September



## GCPBA (Oct 22, 2009)

This is a July 27, 2018, update from Paul Davidson at Glen Canyon Dam.

The release volume from Glen Canyon Dam for August, 2018, will be 900,000 acre-feet. Hourly releases during August are anticipated to fluctuate between approximately 10,500 cfs in the nighttime and 18,500 cfs in the daytime. On weekend days in August releases will be steady near 11,500 cfs. Additionally, in August, the LTEMP Bug Flow experimental fluctuation pattern will occur as described below.

The anticipated release volume for September, 2018, is 670,000 acre-feet. This will be confirmed in a subsequent directive toward the end of August.

Please note, the monthly volumes for August is set, the Bug Flow experiment does not change monthly or weekly volumes.

(GCPBA note - Read about "Bug Flow" here: The Bugflow Experiment).

The Bug Flow experiment consists of steady weekend releases from Glen Canyon Dam and normal fluctuating releases during the weekdays. The steady weekend flows are expected to provide favorable conditions for insects to lay eggs along the Colorado River downstream of Glen Canyon Dam, while the minimum flows on weekdays are designed to be similar to flows on the weekends, thus preventing the eggs from drying out.

Performing this experiment will not affect the Monthly or Weekly planned release volumes. The affect will only be to the daily distribution volumes, and the peak and low daily flow rates.

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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