Runoff/snowpack news: San Miguel, Dolores, Animas, San Juan and Rio Grande basins melted out

From the Estes Park Trail-Gazette (David Persons):

The cooler weather last weekend in the high country is slowing down the annual spring runoff into a more manageable, downward trending flow along the Big Thompson River, say federal water officials.

But, that doesn’t mean there won’t be times when the water level in the Big Thompson River – especially at night – rises a little.

“As we move into the rest of the week, visitors to and residents of the canyon will continue to see nightly flows rise with snow runoff, enhanced some by rain runoff, just as they have seen for the past week,” said Kara Lamb, the Public Information Officer for the U.S. Bureau of Reclamation’s Eastern Colorado Area Office in Loveland.

The slower runoff flow, however, is causing some changes about how the Bureau of Reclamation manages the runoff.

Lamb said water that had been diverted to the canal that feeds Horsetooth Reservoir has filled the reservoir. Its water level elevation has been fluctuating within the top foot of its storage capacity between 5,429 and 5,430 feet. With it back up near 5,430, the Bureau of Reclamation has stopped sending water to Horsetooth and increased the return of Big Thompson River water to the canyon at the canyon mouth using the concrete chute. By 5 p.m. Monday evening, the chute was running around 300 cubic feet per second, Lamb said.

Another change involves water from the Western Slope. Over the past few weeks during the high peak of the runoff, the Bureau of Reclamation stopped bringing water from the Western Slope by way of the Alva B. Adams Tunnel. Plans are now to restart that process.

“The drop in snowmelt runoff inflows will allow us to begin bringing some Colorado-Big Thompson Project West Slope water over again using the Alva B. Adams Tunnel,” Lamb said. “We anticipate the tunnel coming on mid-week and importing somewhere between 200-250 cfs.

“Once the tunnel comes back on, we will also turn the pump to Carter Lake back on, probably on Wednesday of this week.”

Lamb said Carter Lake’s water level elevation dropped slightly during runoff operations. It currently is around 95 percent full. Now that Horsetooth is basically full, Carter will receive the C-BT water until it is full.

Pinewood Reservoir, between Lake Estes and Carter Lake, is seeing a more typical start to its summer season, Lamb added.

From National Geographic:

From Greenland’s ice sheets to Himalayan glaciers and the snowpacks of western North America, layers of dust and soot are darkening the color of glaciers and snowpacks, causing them to absorb more solar heat and melt more quickly, and earlier in spring.

This trend toward darker snow from soot and dirt has been observed for years. Sources vary from dust blowing off deserts and snow-free Arctic land, to soot from power plants, forest fires, and wood-burning stoves. But now soot and dust are taking a greater toll, according to a report released this week, causing Greenland’s ice sheets to darken—and melt—at a faster rate in spring than before 2009.

This matters because Greenland is mostly covered in ice, and meltwater from thawing continental glaciers like those found in Greenland and Antarctica flows into the ocean, causing seas to rise. Greenland, the world’s largest island, holds enough ice that if it all melted seas would rise—likely over centuries—up to 20 feet.

This darkening of Greenland ice by soot and dirt will probably cause seas to rise faster toward the end of this century than previously forecast.

From email from Reclamation (Kara Lamb):

Things have been steady at Ruedi regarding runoff. We are anticipating a fairly straightforward week. Unless there is a significant weather event, we do not plan on making any changes at Ruedi until Friday. If the current conditions remain, we plan to reduce our release from the dam by about 100 cfs on Friday .

Ruedi Reservoir is still filling.

Current releases are about 350 cfs–the Rocky Fork is contributing another 50 cfs.

If the plan stays in place, by Friday night, the Ruedi Dam gage will be reading closer to 300 cfs. About 250 cfs of that will be released from Ruedi. The rest will be from Rocky Fork.

From email from Reclamation (Erik Knight):

Releases from the Aspinall Unit are being reduced over a 2 day period which began yesterday afternoon. The spills at Blue Mesa and Morrow Pt dams will end this afternoon, June 11. This will reduce the spill at Crystal and should have the effect of decreasing flows in the Gunnison River through the Black Canyon to the 6,000-6,500 cfs range. Currently we expect this level of release to be sufficient to sustain over 8,070 cfs at the Whitewater gage.

Leave a Reply