Snowpack/runoff news: A beautiful upslope storm for the South Platte Basin

Click on a thumbnail graphic to view a gallery of snowpack data from the Natural Resources Conservation Service.

From The Pueblo Chieftain (Matt Hildner):

The irrigation season opened at the beginning of the month and stream-flow forecasts are down in the basin’s two major rivers — the Rio Grande and the Conejos.

“It definitely is below average,” Division Engineer Craig Cotten said.

Stream flows on the Rio Grande at Del Norte, which is the point where many of the irrigation ditches in the northern half of the valley begin to pull from the river, are projected to be 500,000 acre-feet this year…

The Conejos is predicted to have 235,000 acre-feet this year, which is below the average of 330,000 acre-feet.

But the poor stream flow forecast, if it holds true, means Colorado will also have a lighter delivery obligation under the Rio Grande Compact, which divvies up the river’s flows between Colorado, New Mexico and Texas.

On the Rio Grande, the state is projected to have to send 127,000 acre-feet from the beginning of April through the end of the year.

The obligation on the Conejos during that same time frame is 31,000 acre-feet…

But Colorado got a head start on its deliveries because of a warmer than average March that ate away at snowpack in the San Juan Mountains.

“We did deliver significantly more in March to the downstream states, so that’s really good,” Cotten said.

The March runoff, which came before irrigators had opened their headgates, was about 2.5 times larger than normal on both rivers…

Curtailment on the Rio Grande is currently at 6.4 percent, while that figure on the Conejos is 15 percent.

From The Pueblo Chieftain (Chris Woodka):

A few weeks ago, Arkansas River water users were speculating whether Lake Pueblo would be able to hold enough water to avoid triggering releases to increase flood containment capacity. After more than a month without substantial snow accumulation, it’s apparent the reservoir won’t be overflowing anytime soon.

About 3-4 inches of snow already had fallen in Chaffee and Lake counties overnight Thursday and more was expected to accumulate during the day. It will take a lot more to boost the region’s dwindling snowpack, however.

“There’s snow in the upper reaches of the Arkansas River basin, but the southern part of the basin is hurting,” said Roy Vaughan, manager of the Fryingpan-Arkansas Project for the U.S. Bureau of Reclamation.

The snow already has melted out at lower elevations under about 10,000 feet, although some high-altitude sites are still holding up well. Statewide, prior to Thursday’s snowfall, snowpack was 54 percent. That’s troubling, because this is the peak time of year for snowpack. On the other hand, more snow could arrive later, as it did last year and in 2011, Vaughan said.

The Arkansas River basin was at just 61 percent of median, although higher sites in the Upper Arkansas basin were 80-100 percent of average. But the snow has been melting.

At Independence Pass, for instance, snowpack was 92 percent of normal Thursday, but the depth had decreased to 3 feet from 4 feet a month earlier.

Meanwhile, the Rio Grande basin is lagging at 36 percent of average.

On the positive side, major reservoirs are relatively full. Turquoise Lake, which was lowered to make room for imports, is at 94 percent of average; Twin Lakes at 103 percent; and Lake Pueblo at 129 percent.

The Southeastern Colorado Water Conservancy District board learned Thursday it may have less water to allocate next month. Vaughan dropped the estimated of imports to 47,000 acre-feet (15.3 billion gallons), down from 53,000 acre-feet at the beginning of the month.

Optimism is washing away further down the Arkansas Valley as well.

Division Engineer Steve Witte told the board full allocations for well users have been approved for the first time in four years, but cautioned plans could change.

“The approval is subject to change, depending on water supply,” he said.

There are some bright spots in the water picture. Colorado’s state line deliveries to Kansas under the Arkansas River Compact Supreme Court decision remain at a 40,000 acrefoot surplus, although that’s slipped 18,000 acre-feet from last year.

Deliveries are measured on a 10-year rolling average, so the 11,000 acre-foot surplus from 2005 and a 7,000 acre-foot deficit in 2014 reduced Colorado’s advantage.

West Drought Monitor April 15, 2015
West Drought Monitor April 15, 2015

The U.S. Drought Monitor continues to show Southeastern and Western Colorado in severe drought, which is a lower stage than the extreme and exceptional drought gripping all of California and parts of Oregon, Nevada, Oklahoma and Texas at the present time.

From the Fort Collins Coloradoan (Jason Pohl):

Snow was measured in feet across the mountains west of Fort Collins. About 2 feet piled up in parts of Rocky Mountain National Park, and 52 inches of heavy, wet snow buried an area 8 miles northeast of Four Corners in Larimer County, the National Weather Services reports. Several spotters measured snow 30 to 40 inches deep in areas northwest of Fort Collins.

The spring storm boosted snowpack in the South Platte River Basin to 93 percent of normal, according to Saturday’s update from the Natural Resources Conservation Service. That jump – up from 81 percent on Tuesday — came after more than a month of stagnated snowpack and bucked a trend that was beginning to mirror a parched 2012. Levels are now almost spot-on with 2013 figures.

Statewide snowpack also climbed after a month-long decline. However, Saturday levels were still just 68 percent of normal.

And for river watchers, the Poudre continues to be flowing nearly three times as high as the historic average of 140 cubic feet per second. Saturday afternoon flows at the mouth of the canyon were recorded at 326 cfs — down from a Friday high of about 420 cfs…

Since the storm rolled in mid-week, 2.8 inches of rain drenched areas in west Fort Collins and near Horsetooth Reservoir — about two inches fell consistently across the city with some localized amounts topping 3 inches, city rain gauge data show.

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