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

Upper Roaring Fork’s streamflow shows down as transbasin diversions resumes

Transbasin diversion resumed around Oct. 12 slowing down streamflow in the upper stretches of the Roaring Fork River.

At Stillwater, located upstream of Aspen, the Roaring Fork River ran at 23 cfs on Oct. 15, or 56.1% of average, down from last week when the river ran at 33.6 cfs and 78.1% of average.

Water through the tunnel that sends Roaring Fork flows east of the Continental Divide went from 1.6 cfs on Oct. 9 to 19.7 cfs on Oct. 15.

The USGS sensor below Maroon Creek recorded the Fork running at 138 cfs on Oct. 15, or 96.5% of average, down from 166 cfs and 122.1% of average, on Oct. 9.

At Emma, below the confluence with the dam-controlled Fryingpan, the Oct.15 streamflow of 383 cfs represented about 100.5% of average. That’s up from 363 cfs on Oct. 9 and from 89.6% of average.

Meanwhile, the Crystal River above Avalanche Creek, which is not impacted by dams or transbasin diversions, flowed at 70 cfs or 69.4% of average. Last week, the river ran at 64 cfs, or 59% of average.

The Colorado River ran at 2,330 cfs at Glenwood Springs, or 107.4% of average, on Oct. 15, up from 2,200 cfs last week, while the Colorado flowed at 3,780 cfs near the Colorado-Utah stateline, or 93.6% 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 water levels keep going down

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 Oct. 15, the reservoir was 37.52% full (based on updated 2017-18 sedimentation data). That’s down from Oct. 9, when the nation’s second-largest reservoir was at 37.61%.

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 Oct. 15, 2022, the reservoir was 25.11% full.

On Oct. 15, Lake Powell’s elevation reached 3,573 feet, or 127 feet from full pool, which is down from 3,573.3 feet on Oct. 9. Last year, on Oct. 15 the reservoir reached 3,530.30 feet in elevation, or 169.7 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.

Air temperatures dropped at ASE

High air temperatures at the Aspen airport went from 73°F on Oct. 1 to 50°F on Oct. 3 before going up to 69°F on Oct. 7 and then dropping to 38°F on Oct. 12, which is about 20 degrees below average. Maximum air temperatures reached 47°F on Oct. 13. Meanwhile, low temperatures went from 45°F on Oct. 1 to 30°F on Oct. 5 before going up to 38°F on Oct. 11, or about nine degrees above normal. Minimum temperatures went down to 29°F on Oct. 13.

Air still clean in Aspen

The air quality in Aspen was “good.” The air quality index for ozone ranged from 30 on Oct. 12-13-14 and Oct. 1 to 39 on Oct. 15.

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,...