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A drought-riddled summer can still make for a fun recreation season on the Upper Snake River. But for dam managers and wildlife stewards, it also means more headaches and question marks.
At least that’s how this summer’s record-breaking dry heat is panning out for much of the watershed and its dams, which are nearing record-low water levels into the fall.
Jackson Lake is 33% full as of late August. Closer to 88% is more normal for this time of year, according to Brian Stevens, the Upper Snake operations manager at the U.S. Bureau of Reclamation.
Three-quarters full is the typical minimum going into winter, but with a dry, warm fall in the forecast, Stevens said the dam could near zero-percent territory, with an anticipated “1 to 10% full range by the end of the fall.”
If the warm temps and sparse rain continue, the Palisades Reservoir in Alpine could lose the ability to generate power from its dam.
“The chance is less than 50% that it happens,” said Stevens.
Several water uses — like irrigation, power generation and ecology — are caught in the fray when there are warmer temperatures and low water levels impacting the Upper Snake’s nine reservoir system.
“We’re trying to balance all of those [uses] given the drought conditions throughout the system,” said Stevens.
To keep up with irrigation needs downstream, dam releases have also been more than average for this time of year, at 5,000 cubic feet per second through mid-September.
The Upper Snake’s water woes are on par with the rest of the West. Water supply and hydroelectricity for millions downstream are at risk at two of the country’s largest reservoirs. Lake Mead and Lake Powell, which pull from the Colorado River, hit record lows this summer. The Flaming Gorge is also below normal levels due to long-term drought and increased dam releases.
Fish take the heat
Since the Jackson Lake Dam pulls water from a relatively shallower point, it releases warmer water than other dams might. This can result in reduced dissolved oxygen, which stresses aquatic life and can be deadly for fish.
“When you have more water that’s stored in Jackson [Lake] that makes up a larger portion of total stream flow, then water temperatures are warmer,” said Dr. Sarah Newcomb, a Snake River headwaters hydrologist with the Jackson Hole chapter of Trout Unlimited.
The warmer water is one of several drought factors that led the Wyoming Game and Fish Department to issue a voluntary fishing closure on the Snake in July.
“Our primary concern is largely associated with catch-and-release angling under warmer water conditions,” said Darren Rhea, the department’s Jackson-based fisheries supervisor. “It can induce mortality if they’re hooked and landed under stressful conditions.”
A first for the department, the daytime closure came after water temps held at or above 70F for several days in July. That’s also when air temperatures nearly broke records in Jackson.
Rhea will have a better idea of how fish took to this year’s unique summer once his department collects more data in October.
“We’ve been through some warm and dry periods, but temporarily,” Rhea said. “I don’t recall in my career seeing a snowpack disappear so rapidly, followed up by such extreme air temperatures during the summer.”
Longer approaches for lake-goers, but more water on the river
Fish aren’t the only ones out of luck. The Colter Bay Marina was forced to close up shop on July 13, nearly two months ahead of schedule.
Jackson Lake scenic boat rides ended July 13, at least two months ahead of schedule. (Jenna McMurtry / KHOL)
Grand Teton Lodge Company usually offers scenic boat rides at the marina through September but called those off for the summer by mid-July. A subsidiary of Vail Resorts, the company declined to comment on the closure.
But Rendezvous River Sports owner Aaron Pruzan said there’s still plenty of put-ins for lake kayakers and paddleboarders at lower shorelines. It just might mean more walking to get there.
“I would see no reason why we’d need to end our season early,” said Pruzan, who also founded the Jackson Hole Kayak School. “Jackson Lake at low water level still provides an amazing experience.”
With the extra releases, surfing Lunch Counter, a famed rapid in the Snake River Canyon, has also been in season longer than is usual.
Forecasts predict the extreme El Niño weather will continue to intensify into the fall. At least 95% of the Intermountain West is experiencing some level of drought already, with most counties breaking heat records.
