Upper #ColoradoRiver #snowpack raises hopes of avoiding Mead shortage declaration #COriver

Westwide SNOTEL basin-filled map February 21, 2017 via the NRCS.
Westwide SNOTEL basin-filled map February 21, 2017 via the NRCS.

From the Las Vegas Review-Journal (Henry Brean):

Federal forecasters now expect the reservoir to avoid its first federal shortage declaration next year, thanks to the boost it should get from what could wind up as the wettest winter on the river’s basin in 20 years.

“We’re in for a good year, no doubt about it,” said Randy Julander, snow survey supervisor for the U.S. Department of Agriculture’s Natural Resources Conservation Service in Salt Lake City.

Storms in Utah, Colorado and Wyoming over the past month have added more than 3 million acre-feet to the water supply forecast for the Colorado. That’s a 10-year supply for Nevada, which gets 300,000 acre-feet from the river each year and uses it to supply the Las Vegas Valley with 90 percent of its drinking water.

SHORTAGE DECLARATION UNLIKELY

The latest forecast from the National Weather Service’s Colorado Basin River Forecast Center calls for the surface of Lake Mead to start 2018 about 3 feet above the trigger line for a shortage declaration that would force Nevada and Arizona to reduce their river use.

Projections in January called for slightly below average flows on the Colorado through this summer, resulting in an 11-foot drop that would take the lake below the shortage line.

Forecasters now expect 9.6 million acre-feet of snowmelt — 134 percent of the average for the past 30 years — to make its way into the river between April and July.

One acre-foot of water is enough to supply two typical valley homes for just over a year. The Colorado River provides water to some 40 million people in the U.S. and Mexico.

Some monitoring stations on the western slope of the Rocky Mountains show roughly twice as much snow as usual for this time of year, and Julander said it is very wet and “ripe” to begin melting into the river system.

“We’ve seen a dramatic and substantial increase in snowpack and soil moisture,” he said. “January and February were absolutely outstanding. It feels good to say that.”

Heavy snow and rain in California also could take some pressure off the overburdened Colorado. The Golden State draws more water from the river than anyone and might be able curb its use and store more of its supply in Lake Mead now that its own reservoirs are filling again following heavy rains in the lowlands and snowfall in the Sierra Nevada.

From The Fort Morgan Times (Jenni Grubbs):

As of Feb. 21, Colorado’s snowpack was sitting at 140 percent of what is considered normal, according to the U.S. Department of Agriculture’s Natural Resources Conservation Service.

That amount has dropped some, though, as only a week earlier, the statewide snowpack was at 147 percent of normal.

Still, this bodes well for Fort Morgan in terms of having plenty of water this summer and fall. It also looks good for Northern Water, which provides that water to the city through the Colorado-Big Thompson pipeline.

“Late spring and early summer snowmelt and runoff from the Rocky Mountains provides most of Colorado’s water supply,” Northern Water’s website explains. “Greater snowpack means favorable water supplies; lower amounts can signal an impending drought.”

The two major river basins that play roles in the water supply for the C-BT pipeline are the Upper Colorado and South Platte, and they had snowpacks of 147 and 142 percent, respectively, in mid-February. Those percentage fell to 140 and 132 as of Feb. 21…

But even with the dips over the last week, the numbers were still well above normal. That could continue to be the case, according to Northern Water.

“The most probable streamflow forecasts are also well above average,” the water district stated.

Further, the C-BT pipeline’s water storage level was “above average” at the start of February, tracking at 121 percent of normal as of Feb. 1.

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