Shoshone "call’ runs upstream valleys
Entering the canyon it is, by standards of the Rocky Mountains, big and grand. But then, coming to a century-old dam, the river disappears entirely for three miles. For eight months of the year in most years, only puddles and boulders are found in what should be a gush and spray of whitewater.
For this three-mile stretch the water is instead earning a paycheck elsewhere. Held back by a dam, the water is then funneled through pipes bored into the limestone cliffs and then, powered by gravity, rushes through turbines to generate electricity in the Shoshone Power Plant.
At 15 megawatts at full capacity, it’s not much electricity when compared with the massive 700-megawatt coal- and gas-fired power plants owned elsewhere in Colorado by Xcel Energy. Even so, that short detour affects nearly everyone upstream, including Summit County and the Eagle Valley.
“First in time, first in right’
Under Colorado water law, this power plant has water rights senior to almost all other users in the basin above Glenwood Canyon – Eagle, Grand and Summit counties. Without Shoshone, says Bill McEwen, water commissioner for the Eagle Valley, “the river would be sucked dry.” There would be no senior right downstream forcing upstream users to pass along water.
The basis for this control of the upper Colorado River are two water filings made by power company officials. Most important is the 1902 appropriation for 1,250 cubic feet per second.
Primarily ranchers lived upstream of Glenwood Canyon in 1902. They irrigated during spring and summer, when water was plentiful. But their year-round needs were minimal. Because of its senior status, Shoshone became the benchmark for winter, when there is naturally less water available in streams.
But in drought years – such as in the 1930s, the mid-1950s, 1976-77 and 1980-81 – winter-like flows can be found in summer. In these times of scarcity, Colorado’s seniority system as applied to water kicks in, sorting out users by date of appropriation and quantity of water. Called the Prior Appropriation Doctrine, this system stipulates “first in time, first in right.” Those who arrived first, putting their water to what Colorado recognizes as beneficial use, have the senior rights.
This means senior claims downstream must be satisfied before newer and hence junior claims upstream are. With state water commissioners like McEwen as intermediaries, senior users getting insufficient water must notify upstream users of the need to stop diverting water until the senior user’s claim downstream is satisfied. In water parlance, this is known as sending out “the call.”
A river no more
How much Shoshone is putting out “the call” in Eagle, Grand, and Summit counties can be judged by whether the river through Glenwood Canyon is gone. If Shoshone Falls is dry, there’s a call on the river. If Shoshone Falls has water, there’s no call.
On average, there’s no call on the river for 95 days a year, usually in April, May and June. At such times, there’s plenty of water for everybody. This year, that window of plenty was down to 40 days. By June 13, a time when Shoshone Falls is normally a furious torrent of water, it had reverted to a trickle.
Most years, water becomes most scarce in late fall and winter. In Eagle and Summit counties, that’s also when local economies are bustling the most.
“Crunch time is mid-October to mid-April,” says Alan Martellaro, the Glenwood Springs-based water engineer for District 5, which includes the headwaters from Aspen to Grand Lake. “This is the time when the fewest options are available to ensure water to meet the call at Shoshone.”
To the extent that snowmaking props up the ski business, Shoshone’s senior call could have held the lid on growth of local ski economies – and perhaps the year-round real estate development induced by skiing. The reason the “Shoshone call” hasn’t slowed the growth can be explained in part by Green Mountain Reservoir, itself an off-shoot of ambitions by sugar beet and corn farmers near Greeley.
The farmers of northeastern Colorado in the 1930s were desperate to get more Western Slope water, especially if the federal government would pay for it. The Western Slope resisted until it got something: Green Mountain. Completed in 1942, the reservoir was designed in part to provide water for farm fields near Grand Junction, mostly in late summer, and in part for future growth on the Western Slope.
Benefit to ski valleys
When Green Mountain was being built by the U.S. Bureau of Reclamation, nobody had yet conceived of the enormity of the ski industry that began arriving 20 years later, nor of the lifestyle-based residential enclaves like Cordillera and Arrowhead that have flourished in the Eagle Valley. Although located on opposite sides of the Gore Range, they’re all upstream of Glenwood Canyon and the Shoshone Power Plant.
That means water impounded at Green Mountain Reservoir during May can be released in November to benefit a house along a golf course at Edwards. Or snow can be made at Vail in December. The important thing is that they’re both upstream of Glenwood Canyon and its power plant.
Releases from other reservoirs – including Granby and Dillon, but more particularly Denver’s Williams Fork and the more recent Wolford Mountain – have also buffered ski-country users from the senior call at Shoshone. These other reservoirs have other purposes and other owners, but they serve the same overall purpose of making the Colorado River more of a year-round workhorse.
Through the growth-on-steroids years of the 1990s, the system worked well for both Eagle and Summit counties. But after most of a decade of heavy snow years, the other side of average has appeared for the past three winters. This spring, the Green Mountain savings account didn’t fill. It fell short by 13 percent. Another 13 percent had to be held back because of geologic instability in the Heeney area.
Just in the nick of time, as it turns out, the ski resorts had been acquiring additional upstream “buckets,” as reservoirs are often called. These buckets allow the ski areas enough water to make snow while leaving enough water in the creeks to meet the call at Shoshone.
Is there enough water in these buckets to make snow? Clearly there is. But is there enough water to keep sustaining the resorts through the sort of dry autumn and winter that the Colorado Rockies have experienced in recent years? That’s the unanswered question.