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

Streamflows are down from last week

At Stillwater, located upstream of Aspen, the Roaring Fork River ran at 32.7 cfs on Sept. 4, or 68.1% of average, down from last week when the river ran at 51.7 cfs and 97.5% 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 2.1 cfs on Aug. 27. It went up to 11.9 cfs on Aug. 31 before dropping to 4.4 cfs on Sept. 4.

The USGS sensor below Maroon Creek recorded the Fork running at 154 cfs on Sept. 4, or 104.1% of average, down from 214 cfs and 129.7% of average, on Aug. 27.

At Emma, below the confluence with the dam-controlled Fryingpan, the Sept. 4 streamflow of 501 cfs represented about 108.4% of average. That’s down from 613 cfs on Aug. 27 and from 124.8% of average.

Meanwhile, the Crystal River above Avalanche Creek, which is not impacted by dams or transbasin diversions, flowed at 113 cfs or 95% of average. Last week, the river ran at 169 cfs, or 116.6% of average.

The Colorado River ran at 2,450 cfs at Glenwood Springs, or 104.3% of average, on Sept. 4, down from 2,620 cfs last week, while the Colorado flowed at 3,820 cfs near the Colorado-Utah stateline, or 112% 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 slowly 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 Sept. 4, the reservoir was 37.95% full (based on updated 2017-18 sedimentation data). That’s down from Aug. 27, when the nation’s second-largest reservoir was at 38.3%.

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 Sept. 4, 2022, the reservoir was 25.34% full.

On Sept. 4, Lake Powell’s elevation reached 3,574.3 feet, or 125.7 feet from full pool, down from 3,575.2 feet on Aug. 27. Last year, on Sept. 4, the reservoir reached 3,531.19 feet in elevation, or 168.81 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 went from 87°F on Aug. 21 to 67°F on Aug. 25, which is about eight degrees below normal, due to rain events before going up to 83°F on Sept. 1. Meanwhile, low temperatures dropped from 56°F on Aug. 20 to 43°F on Sept. 1.

Air quality remains ‘good’ in Aspen

The air quality in Aspen was “good.” The AQI index for ozone ranged from 38 on Sept. 2-3 to 44 on Sept. 4.

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,...