Aspen Journalism is compiling a data dashboard highlighting metrics of local public interest, updated weekly on Tuesdays.
July sees above-average precipitation at Aspen airport
Precipitation measured at Aspen airport was above average in July 2022, with a total of 1.71 inches compared to the 1991-2020 average of 1.64 inches, according to NOAA. With the monsoon rain, July is the most rainy month of the year so far. But according to the 30-year average, the month of April should get the most rain, followed by July. As of Aug. 16, 1.01 inches of rain had fallen on Aspen for the month, which has an average total of 1.48 inches.
Roaring Fork’s streamflow plateaus while Crystal drops to 58% of average
The USGS gauge located on the Roaring Fork River below Maroon Creek measured streamflow at 181 cfs on Aug. 14 or 79.7% of average. That’s down slightly from Aug. 7, when the river was flowing at 184 cfs; however, as a percentage of average, this week’s value rose from last week’s 59.9%. The upper Fork is benefitting from transbasin diversions under Independence Pass halting Aug. 10 due to the Cameo call, which curtails water going to Front Range cities to protect the more senior Grand Valley water rights.
Near Emma, the Roaring Fork was flowing at 477 cfs on Aug. 14, or about 89.3% of average. That’s down from 481 cfs on Aug. 7 but up from that day’s 80.3% of average.
Meanwhile, the Crystal River above Avalanche Creek, near Redstone, flowed at 109 cfs, or 58.6% of average, on Aug. 14. Last week, the river ran at 148 cfs, or 62.2% of average.
Downstream, the Crystal River at the CPW Fish Hatchery bridge ran at 40 cfs on Aug. 14, down from 81 cfs on Aug. 7.
Lake Powell’s elevation is about 9 feet above critical water level
Lake Powell‘s storage remains at one of its lowest levels recorded since it began filling in the 1960s. On Aug. 14, the reservoir was 24.97% full (with a total capacity based on a 1986 sedimentation survey) or 26.05% full (based on 2017-18 sedimentation data), down from Aug. 7, when it was 25.3% full (1986 data) or 26.39% (2017-18 data).
On July 1, 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.
“After inputting the new data on July 1, 2022, storage values at the current elevation were updated, resulting in a decrease of 443,000 acre-feet,“ bureau officials wrote in an email.
Aspen Journalism published a story explaining the recent drop in storage due to sedimentation.
The reservoir’s capacity has fallen since last year, when on Aug. 14, 2021, it was 31.6% full (1986 data).
On Aug. 14, Lake Powell’s elevation reached 3,533.9 feet, or 166.1 feet from full pool, down from 3,535.2 feet on Aug. 7. That puts the water level just 9 feet above the target elevation of 3,525. Powell’s surface elevation this year peaked at 3,539.84 feet on July 3, after it dipped to its lowest level since filling of 3,522.24 on April 22. Last year, on Aug. 14, the reservoir reached 3,551.4 feet, or 148.6 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.
‘Clean’ air reported in Aspen last week
The air quality in Aspen was “good” this past week. The AQI index for ozone ranged from 41 Aug. 11 and 47 on Aug. 14.
- Colorado’s Division of Water Resources
- Bureau of Reclamation
- Aspen Consolidated Sanitation District
- Aspen Global Change Institute