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

Streamflows keep slowing down

Local streamflows are slowing down as snowpack is entirely melted.

At Stillwater, located upstream of Aspen, the Roaring Fork River ran at 47.6 cfs on Aug. 20, or 82.1% of average, down from last week when the river ran at 56.5 cfs and 84.3% of average.

Water through the tunnel that sends Roaring Fork flows east of the Continental Divide dropped from 114 cfs on July 16 to 40.5 cfs on July 23, down to 1.8 cfs on Aug. 20.

The USGS sensor below Maroon Creek recorded the Fork running at 191 cfs on Aug. 20, or 94.6% of average, down from 238 cfs and 98.8% of average, on Aug. 13.

At Emma, below the confluence with the dam-controlled Fryingpan, the Aug. 20 streamflow of 545 cfs represented about 104.4% of average. That’s down from 595 cfs on Aug. 13, but up from 109.2% of average.

Meanwhile, the Crystal River above Avalanche Creek, which is not impacted by dams or transbasin diversions, flowed at 154 cfs or 93.9% of average. Last week, the river ran at 183 cfs, or 94.8% of average.

The Colorado River ran at 2,500 cfs at Glenwood Springs, or 95.1% of average, on Aug. 20, down from 2,560 cfs last week, while the Colorado flowed at 3,610 cfs near the Colorado-Utah stateline, or 102.6% 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 dropping

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 Aug. 20, the reservoir was 38.57% full (based on updated 2017-18 sedimentation data). That’s down from Aug. 13, when the nation’s second-largest reservoir was at 39.01%.

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 Aug. 20, 2022, the reservoir was 25.9% full.

On Aug. 20, Lake Powell’s elevation reached 3,576.2 feet, or 123.8 feet from full pool, down from 3,577.1 feet on Aug. 13. Last year, on Aug. 20, the reservoir reached 3,533.31 feet in elevation, or 166.69 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 on the rise

High air temperatures at the Aspen airport went from 76°F on Aug. 12 to 85°F on Aug. 17, nine degrees above normal. Meanwhile, low temperatures ranged from 41°F on Aug. 9 to 52°F on Aug. 16.

‘Good’ air quality in Aspen

The air quality in Aspen was “good.” The AQI index for ozone ranged from 37 on Aug. 14 to 46 on Aug. 18.

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,...