Over-stressed Colorado River takes on another load; Blue Mesa reaches 87% full

pat Crystal falls 2011

A viewer (upper right) is dwarfed by this earlier spill from Crystal Dam on the Gunnison River. The reservoir was forecast to begin spilling this year on May 18. Dave Buchanan

Water news from the Front Range today is focused on the approval of the Record of Decision for the Windy Gap Firming Project, which features construction of the proposed Chimney Hollow Reservoir, a 90,000 acre-foot impoundment north of Denver that will be filled with water from the Colorado River.

The reservoir will provide water for cities within the Northern Colorado Metropolitan Water District.

blog post from Coyote Gulch gives the details plus links to various sources.

The most-recent Hutchins Water Center report was sent out today from the Water Center at Colorado Mesa University.  Among the topics covered is the latest Blue Mesa runoff forecast from the Bureau of Reclamation reported earlier this week.

The May 15 forecast is for 825,000 acre feet of unregulated inflow into Blue Mesa, amounting to 122 percent of the 30-year average and down a bit from the forecast two weeks earlier.

As expected, the latest forecast is down considerably from the Feb. 15 forecast of 970,000 acre feet, which illustrates the difficulty of making long-range forecasts when dealing with something as variable as the weather.

As one hydrologist told me at the Water Center meeting earlier this week, “I’ve been doing this for 36 years and this year is the craziest I’ve seen.”

Blue Mesa currently is 87 percent of full and there still is a good chance it could fill this spring, especially if the current round of wet spring storms continues in the upper Gunnison Basin.

What the new forecast does is moves the water-year classification for the runoff from “Moderately Wet” to “Average Wet,” in turn reducing flow targets to benefit endangered fish in the 19-mile reach of the Gunnison River downstream of Palisade.

Also changed are the peak flows to meet the Black Canyon Water Right and the flushing flows needed to keep the river channel clear through the canyon. Crystal Dam was expected to start spilling May 18 and peak sometime on the 23rd or 24th, with estimated peak flows through the Black Canyon reaching the 10,800 to 12,000 cfs range.

You can find a schedule of flows below the Gunnison Tunnel here.



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