Low precip, soil moisture and streamflows
By Katherine Nettles
Despite the strong start to summer with snowfall totals well above average, Gunnison County has slipped back into drought conditions this fall across two-thirds of the Gunnison River Basin. The basin’s dry fall and relatively dry summer have added up to low soil moisture and streamflow levels going into winter, but reservoirs are holding up and another good snow year would help.
According to Upper Gunnison River Water Conservation District senior water specialist Beverly Richards, 62% of the county is now experiencing moderate drought conditions, with 2.4% of the county in severe drought conditions.
“Last summer we had a brief period where we had no drought at all in Gunnison County. That is not the case anymore, and that is due to lack of precipitation as well as other factors that the drought monitor uses to determine conditions,” said Richards during a basin update to Gunnison County commissioners on Tuesday.
She showed precipitation levels from the past 30 days, which ranged from 25-100% of normal. “But this time of year is often very dry [in Gunnison County], so even 100% of normal is still not a lot of precipitation.”
And it isn’t likely to change anytime soon. The current seasonal forecast shows dry conditions are likely to continue for another couple months with the exception of some areas in the northern part of the county and into Hinsdale County that might receive up to two inches of rain in the next week or so.
Parched soils and streams
Richards said another indication of drought is soil moisture, which is currently at 52% of average. This is very low going into winter, said Richards, and local water specialists were hoping to have more at the change of seasons. “Soil moisture did peak at 100% of normal back in May, but has since declined,” she said.
Local streamflow gauges have also reduced over the last month, and while the three streams located in the northern part of the basin have come up slightly from what was reported in September, all the gauges are below the historical averages.
“That’s another indication of just how dry conditions are right now,” said Richards.
Reservoirs in decent shape…except Powell
Reservoir storage for the entire Gunnison Basin is at 58% of capacity. Without factoring in Paonia and Silver Jack Reservoirs which are being drawn down for agricultural releases, the remaining area reservoirs are at 80%. Reservoir storage in just the Upper Gunnison (Taylor and Blue Mesa) is 72% full.
“We are releasing 100 [cubic feet per second] out of Taylor Reservoir right now, and had originally intended that to last through the winter, but our board asked last night for us to check and be sure that is still something we’re able to do due given the dry conditions,” said Richards.
Unregulated inflow into Blue Mesa for water year 2023 (which ended on September 30) was estimated to be around 890,000 acre feet, or 98% full. Blue Mesa levels were around 76% last month, and the Bureau of Reclamation is drawing it down to about 70% for winter.
The Upper Colorado River Basin reservoir storage is about 67% full overall. “Most reservoirs in the Upper Colorado River drainage are in pretty good shape, except of course, for Lake Powell which is at 37%,” said Richards. The current elevations at Lake Powell are 3,572 feet. She said it peaked at 3,584, and “that was a good recovery for the conditions in Lake Powell, however it is still declining at this point.”
Gunnison County commissioner Liz Smith asked if models for winter forecasting are still a bit too far off, and Richards said that despite continual uncertainty around the El Niño conditions being forecast, she had seen a graph on Monday showing that there might be above average precipitation in the basin just like last year. She noted that it will be a while longer before those models can give an accurate prediction.
“But maybe something will come in and it will surprise us,” said Richards of the near-term.