# Grand Canyon, Colorado River Flows - April, May, & June



## GCPBA (Oct 22, 2009)

Here is an April 17 update from Paul at the Glen Canyon Dam, with further details about the "Bug Flow Experiment":

The release volume from Glen Canyon Dam for April, 2018, will be 705,000 acre-feet. Hourly releases during April, 2018, are anticipated to fluctuate between approximately 8,650 cfs in the nighttime and 15,000 cfs in the daytime.

The anticipated release volume for May, 2018, is 705,000 acre-feet with daily fluctuations between approximately 7,050 cfs in the nighttime and 13,390 cfs in the daytime.

The expected release volume for June, 2018, is 760,000 acre-feet with daily fluctuations between approximately 8,850 cfs in the nighttime and 16,450 cfs in the daytime.

The Glen Canyon Dam Experimental Technical Team (Technical Team) recommends that experimental Macroinvertebrate Production Flows (Bug Flows) be implemented at Glen Canyon Dam beginning May 1 through August 31, 2018.

(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.

At this time we do not have a firm confirmation for a Bug Flow event. However, a final determination for this experiment will likely be made near the end of April.

GCPBA RiverNews is a service of Grand Canyon Private Boaters Association.
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## David L (Feb 13, 2004)

Thanks for the info of the Bug Flow. I'll watch out for it as I float the river starting this week!

Good to see more work about the dam effects and adjusting flow releases for environmental reasons.

Now if they can only figure out a way to get the silt from many miles above the dam down into the river below it! Without it costing billions of dollars.

Over the years I've seen many beaches at Grand Canyon camps become virtually gone. It's very sad to float past Carbon and Lower Tapeats and Clear Creek, for example, and remember the way they used to be.


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