Spring snow meltoff close to reaching its peak for Gunnison

Blue Mesa expected to fill this year

By Katherine Nettles

The Gunnison River could reach its peak runoff volume in the next week or two, according to Upper Gunnison River Water Conservancy District (UGRWCD) officials.  UGRWCD staff gave a general update to Gunnison County commissioners this week on a range of water topics, from Colorado River agreement talks and potential studies on local irrigation to how reservoirs and rivers are faring in late spring. 

Spring runoff, reservoir storage and water levels

UGRWCD senior water resource specialist Beverly Richards reported that the  Gunnison River at the Gunnison Whitewater Park was flowing at 3,210 cubic feet per second (CFS) last weekend, and is very close to peaking. 

Richards said there is currently only one small portion of Gunnison County to the west that is facing drought, and the three month outlook shows drought conditions not recurring with the exception of a few areas to the north.

Richards reported that precipitation has generally been within the historic normal range in the past 30 days, while snow water equivalent (SWE) maps show 193% of normal for the entire Gunnison Basin and 153% of normal for the upper basin. SNOTEL sites where SWE is measured are melting out. “But that was for May 19,” she said, which reflects that in May there isn’t usually much snow left. 

The entire Gunnison Basin water storage is at 75% of average;  reservoir storage for the Upper Gunnison Basin is 61%; and projected unregulated inflow for Blue Mesa Reservoir is at 131% of average. 

Richards said Blue Mesa is projected to be 97% full with a max fill amount of 102,869 acre feet. There is no indication from the Bureau of Reclamation (BOR) as of yet about how much water might be called downstream. 

“Reservoir storage across the Upper Colorado River is going up, but Lake Powell is expected to only be about 37% full,” said Richards, due to the volume that will come out. For perspective, she offered an estimate that Lake Powell could be filled in three years if the region had the same kind of snowy year as 2023, and if no one took water out. With the reality of outflows, however, she said it would take 6 to 8 years with winters like this one to refill Lake Powell.

Lower Basin agreement, water studies and an additional office 

UGRWCD manager Sonja Chavez discussed the news this week that the lower Colorado basin states (Arizona, California and Nevada) came to an agreement on how to reduce their usage by 3 million acre-feet. The other upper basin states are also in agreement with that plan, reviewed Chavez. 

She said that while the BOR  had withdrawn doing an environmental impact statement (EIS) associated with the plan, the upper basin states want to see an EIS. “I expect we’ll hear more about this in the next few days, but it’s good news,” she said. 

Relatedly, the Colorado River District had suggested doing a pilot study on both the lower Gunnison Basin row crop farming and the upper Gunnison Basin stockgrowers, involving demand management for about 10,000 acres. “We didn’t receive good feedback from stockgrowers. Obviously, the concern we have in the upper basin is anytime we do fallowing, we see three to five years of impact to productivity,” Chavez said.  

Alternatively, Chavez said the UGRWCD has proposed doing a detailed water budget and irrigation return flow study in collaboration with the US Geological Survey (USGS). It would be a five to ten year program to gather data. 

“We want a very strong program if we do this,” she said. “Our belief is that we’re going to continue to see drought over the years, and that the data we get from a study like that could lend a lot of information to what we see anecdotally. And what we tend to see is that if you shut off headgates and eliminate irrigation in certain areas in years of drought, what you see is an effect to the entire system,” said Chavez.

She said the UGRWCD recently purchased unit A in their building complex on New York Avenue in Gunnison where the Bureau of Land Management was formerly located. She said this will help secure the space they need with a growing staff.