Snowpack and runoff forecasts grow as winter nears its end


Lake fog hangs over Blue Mesa Reservoir on a minus 7-degree morning earlier this winter. The reservoir is expected to fill this summer thanks to abundant snowpack.

Despite the welcome but unnerving warm spell western Colorado mostly enjoyed in early and mid-February we’re back into winter. This week, anyway, with temperatures around 20 degrees today (Feb. 23) and forecast to say around seasonal though the weekend.

I say “mostly enjoyed” because fruit growers, who work often on hope as much as science, saw some of their apricot trees inch ever-closer to an early bud, a certain precursor of disaster should a late fruit-killing frost hit the Grand Valley. But buds are rather pretty hearty, as some growers and viticulturists have noted, as they’re protected by several layers of outer growth. Young leaves, though, are another story: once the bud “breaks” and inflorescence begins, the degree of susceptibility increases dramatically.

The cold weather, after a February that the National Weather Service says has been the warmest February on record since 1907, brought more snow to an already abundant snowpack and another bump in runoff forecasts for the Upper Colorado River Basin. As of Feb. 15, the Western Colorado office of the Bureau of Reclamation said the snowpack in the Upper Gunnison Basin was 166 recent of average, and translated to a predicted April – July runoff inflow into Blue Mesa Reservoir on the Gunnison River to be around 970,000 acre feet. That amounts to 144 percent of the 30-year average.

Which, if things remain stable (always a gamble when dealing with weather-related conditions), means Blue Mesa, now at 69 percent full, undoubtedly will fill this summer.As will Morrow Point and Crystal reservoirs immediately downstream, and it’s a sure that much water would send flows over the top of Crystal.

The Gunnison flows will join the rest of the Colorado River Basin in giving a much-needed to water levels in both Lake Powell and Lake Mead. Powell’s inflow are predicted to be around 9.6 million acre feet, 134 percent of average. This could lead to some extra water headed toward Lake Mead in addition to the 8.23 man demanded by the Colorado River Compact. Neither reservoir is expected to fill, of course, since both are so far down.

Even the Dolores River and southwest Colorado are flush this year after at least five years of low snowpack, and a recent announcement from Dolores Water Conservancy District Chief Engineer Ken Curtis confirmed an early summer spill of McPhee Reservoir. “There’s enough snow on the ground that we are comfortable planning a spill,” Curtis told radio station KSJD.

He said the snowpack in the Dolores Basin hit 100-percent of average by February 1, something that normally doesn’t happen until April 1. “The real numbers game is that McPhee Reservoir is 90,000 acre feet down from full and the minim of two (runoff) forecasts is 300,000 acre feet of inflow and most-probable is up closer to 400,000,” Curtis said. “So even that minimum inflow is going to fill up McPhee and make for some excess.”

Don’t start packing for that river trip quite yet. Curtis said “managed releases” won’t begun until at least mid-April and then the levels will be determined by how much water actually materializes. It’s not just boaters who will benefit, Curtis said.

“This excess water provides a lot of scoring flows and other benefits to the fishery” as well as being of ecological importance, Curtis said.

When asked about duration of the spill, Curtis emphasized it’s still early in the forecast.

“I think we’re looking at between 30 and 70 days of spill. That’s a big target and that’s why we don’t want to get too specific now,” he said. “But we will keep running the (runoff) models and give better indications as we get closer to April.”

You can follow the Dolores flows here.

– Photo/story by Dave Buchanan




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