Aspen Journalism is compiling a data dashboard highlighting metrics of local public interest, updated weekly.

Streamflows down from last week

Transbasin diversion resumed around Oct. 28 and shut down on Nov. 4 before starting again on Nov. 5.

At Stillwater, located upstream of Aspen, the Roaring Fork River ran at 15.7 cfs on Nov. 12, or 47.6% of average, which is down from last week when the river ran at 21.4 cfs and 62.9% of average.

Water through the tunnel that sends Roaring Fork flows east of the Continental Divide went from 1.6 cfs on Oct. 22 to 15.2 cfs on Oct. 29 and then to 21.4 cfs on Nov. 5. On Nov. 12, it slowed down to 8.2 cfs.

The USGS sensor below Maroon Creek recorded the Fork running at 109 cfs on Nov. 12, or 100.9% of average. On Nov. 5, the river was running at 128 cfs.

At Emma, below the confluence with the dam-controlled Fryingpan, the Nov. 12 streamflow of 297 cfs represented about 96.1% of average. That’s down from 316 cfs on Nov 5 and 95.5% of average.

Meanwhile, the Crystal River above Avalanche Creek, which is not impacted by dams or transbasin diversions, flowed at 55 cfs or 74.1% of average. Last week, the river ran at 65 cfs, or 82.7% of average.

The Colorado River ran at 1,610 cfs at Glenwood Springs, or 88% of average, on Nov. 12, down from 1,810 cfs last week, while the Colorado flowed at 3,570 cfs near the Colorado-Utah stateline, or 90.8% of average.

Aspen Journalism is compiling real time streamflow data. You can find all the featured stations from the dashboard with their real-time streamflow on this webpage.

Lake Powell’s elevation remains unchanged from last week

Lake Powell‘s water levels began their seasonal rise in mid-March as warming temperatures initiated snowmelt, after the reservoir in the winter dropped to its lowest level on record since filling. Water levels peaked in early July and are now slowing decreasing. On Nov. 12, the reservoir was 37.27% full (based on updated 2017-18 sedimentation data). That’s slightly down from Nov. 5, when the nation’s second-largest reservoir was at 37.29%.

Last year, on July 1, 2022, the Bureau of Reclamation revised its data on the amount of water stored in Lake Powell, with a new, lower tally taking into account a 4% drop in the reservoir’s total available capacity between 1986 and 2018 due to sedimentation. Aspen Journalism in July published a story explaining the that drop in storage due to sedimentation. We will be now using the 2017-18 sedimentation data only.

On Nov. 12, 2022, the reservoir was 24.88% full.

On Nov. 12, Lake Powell’s elevation reached 3,572.3 feet, or 127.7 feet from full pool, which is the same as on Nov. 5. Last year, on Nov. 12 the reservoir reached 3,529.39 feet in elevation, or 170.61 feet from full pool.

The “minimum power pool” for turbines generating hydropower at the Glen Canyon Dam is 3,490 feet, and 3,525 feet has been set as a buffer to ensure that the reservoir and the turbines can continue to function properly.

Swinging air temperatures at ASE

High air temperatures at the Aspen airport increased from 30°F on Oct. 29 to 63°F on Nov. 6, which is about 17 degrees above average, before dropping to 41°F on Nov. 9. Meanwhile, low temperatures went from 2°F on Oct. 30 to 32°F on Nov. 7 before going down to 17°F on Nov. 9.

Clean air in Aspen

The air quality in Aspen was “good.” The air quality index for ozone ranged from 33 and Nov. 8 to 43 on Nov. 11.

Editor’s note: Correction was made to the Roaring Fork’s streamflow below Glenwood Springs.

Laurine Lassalle is Aspen Journalism’s data desk editor, where she works to catalogue and analyze local public data. She also heads our our “Tracking the Curve” project, documenting COVID-19 in Pitkin,...