Blue Mesa remains 90% full
By Katherine Nettles
It might be time for rain dances as an abnormally hot, dry summer in the Gunnison Basin has started to have an impact on surrounding forests, meadows and watersheds. In the monthly basin report provided to Gunnison County commissioners on Tuesday, August 8, Upper Gunnison River Water Conservancy District (UGRWCD) staff shared that as of August 1, 87% of the county is now in abnormally dry conditions from lack of precipitation during most of June and July. While temps have gotten a bit cooler in August, it has not been enough to make a difference and upcoming forecasts do not include precipitation in the coming weeks.
“We had no drought conditions from June 20 to July 11,” said UGRWCD water resource specialist Beverly Richards, referring to the effects of a cool, wet spring and above average winter snowpack. “But since then, the soil moisture has started to dry up, and precipitation has been almost nonexistent.”
Richards said the unusually high temperatures, ranging from 1 to 6 degrees Fahrenheit above normal for the past 30 days, have expedited the drying process. “It’s not helping the [Lowline] fire either,” she said of the 1,800+ acre wildfire burning 10 miles southwest of Crested Butte.
Local water supply has started to show the impacts of the dry spell, said Richards. The streamflow gauge at Tomichi Creek on the Gunnison River is slightly below normal. “All gauges except for the Taylor River at Almont are below historical average,” she added. “That of course, is in part due to the drier conditions that we’ve been experiencing.” The Gunnison River dropped last weekend (August 4–6) from 836 cubic feet per second (cfs) to 721 cfs. “The levels are dropping pretty quickly out there without any kind of precipitation to bolster them,” said Richards. The Slate River above Baxter Gulch is currently at 48 cfs, while the historic average is 53. “So, a little low,” she concluded.
Reservoir storage across both the Upper Gunnison River Basin and the entire Gunnison River Basin are at 90% of average. According to the Bureau of Reclamation (BOR), the Aspinall operations unit is reflecting that unregulated inflow to Blue Mesa reservoir from April through July was 133% of average, at 845,000-acre feet. The end-of-year content of Blue Mesa is projected to be 675,000-acre feet, or 82% of average.
The BOR will be drawing Blue Mesa down to 70% content to meet their targets for the winter, which is still considerably higher than Blue Mesa was last winter, noted Richards. “That will be a great benefit, particularly if we don’t see the kind of snow that we saw last year.”
On the Upper Colorado River Basin, total reservoir storage is at 81%, and Taylor Park reservoir is 120,000-acre feet, or 128% of the 30-year average, for April through July.
Taylor Park inflows are in the top 25% of historical inflows. “That has really helped to get the level up in Taylor Reservoir,” said Richards.The projected fill amount is 103,000 acre feet, and releases out of the reservoir were reduced to 350 cfs on August 3 to begin working toward winter target flows.
The target for Taylor reservoir at the end of the year is 76,700 acre feet, or 72% full.
Downstream, Lake Powell has rebounded from 27% full on this date in 2022 to 40% full in 2023 after substantial inflows. The total inflows to date for this water year at Powell are 11.2 million acre feet, which Richards said was 229% of the inflows during water year 2022. “That’s a great increase for Lake Powell,” she said. So far, 7.38 million acre feet, or 98% of what is required, have been released to downstream users from Lake Powell this year.
County commissioner Liz Smith commented that it was almost a reverse of last year, when monsoons came in heavy and people hoped in vain that it would fill Blue Mesa. “This year soils were better off and we’ve had quite the opposite effect with the dry heat,” she said.
“A lot of people were expecting that the monsoons would come, and that just didn’t happen,” concluded Richards.
UGRWD manager Sonja Chavez said the different consecutive years have aided in gathering data about the harmful algae blooms at Blue Mesa under varying conditions.