Pondering the snowmaking equation
SUMMIT COUNTY – Despite doubts prompted by the severity of this summer’s drought, Summit County appears to have enough water for snowmaking this winter.
“Right now, the stream flows are at a place where the ski areas can take water and start making snow without having to worry about minimum stream flow requirements,” said Scott Hummer, water commissioner for the Blue River Basin, which includes Summit County.
Though most streams continue to flow at levels below the historic average (only Tenmile Creek outside of Frisco is running at its mean), they are flowing above the historic minimums recorded earlier this summer, Hummer said. Recent precipitation has helped raise water levels, and stream flows now are above those recorded in mid-July.
How much water is used for snowmaking this year will depend on factors such as stream flows, temperature and local precipitation, he said.
“At certain stages of flow, there are mitigation requirements that come into play,” Hummer said. “If the flows get low enough, snowmaking can be curtailed completely.”
To date, Copper Mountain is the only resort in Summit County that already has commenced it’s snowmaking operations.
Officials at Breckenridge and Keystone said earlier this month they hoped to start making snow by mid-October, but Senior Vice-President of Vail Resorts, Paul Testwuide, said Friday the end of the month is more likely.
“We don’t really go by the dates. We go with the weather patterns,” he said. “When it gets cool enough on a consistent basis, then we’ll start making snow.”
Last season, Copper Mountain used 292.5 acre-feet (just over 95 million gallons) of water for snowmaking, according to Copper Mountain Communications Coordinator Beth Jahnigen.
Breckenridge used 525 acre-feet (just over 170 million gallons), and Keystone use about 700 acre-feet (just over 228 million gallons), Testwuide said.
The water used to make snow at Breckenridge last year, for example, could have served 1,500 to 2,100 mountain homes for one year.
According to a fact sheet from the Colorado Department of Natural Resources, that is only a fraction of the water used for other purposes, such as agriculture and municipalities.
Of the state’s 24 Colorado Ski Country resorts (which does not include Wolf Creek), 21 make snow, and the combined amount of water used annually is less than that used to irrigate six golf courses each year, the fact sheet says.
Water and ski area officials will continue to monitor stream levels to ensure there is enough water for snowmaking, said Scott Fifer, a hydrologist with Resource Engineering in Glenwood Springs. The snowmaking season typically lasts from mid-October through December.
An agreement between ski areas and the Colorado Water Conservation Board in the late 1980s “established minimum stream flows in the respective reaches below the snowmaking points of diversion,” Fifer said. “Each ski area monitors the streams to ensure the minimum flows are being met. The ski area’s diversions are limited by various instream flow requirements.”
Should the flows near that minimum, the ski areas would be required to cut back their snowmaking – perhaps curtailing it altogether, Fifer said.
According to Hummer, all four ski resorts have water rights in Clinton Reservoir, which is located next to Highway 91 between Copper Mountain and Leadville.
The water stored in that reservoir allows the ski areas to divert water from streams elsewhere in the county, Fifer said.
For example, he said, if A-Basin, Keystone, Breckenridge and Copper used a combined 10 acre-feet of water in a day, that water must be replaced for downstream users. Officials from Denver Water would release 10 acre-feet from Williams Fork Reservoir (near Kremmling) as the replacement, but the ski areas still would “owe” Denver Water the 10 acre-feet used.
Most of that water would return to Denver Water in the form of spring runoff, when the man-made snow melts in the spring. But water experts have determined that 20 percent of the water used for snowmaking is lost through evaporation or sublimation.
It is the 20 percent lost that is replaced by the water in Clinton Reservoir, Fifer said.
Because of this year’s drought, Fifer said he expects the ski areas may depend more heavily on snowmaking this year. But Testwuide didn’t seem worried.
“Right now, we have 550 acre-feet available in storage (for Breckenridge) in Goose Pasture Tarn and Blue River reservoirs,” he said. “So (Breckenridge has) more water than they used last year – and last year was a very dry year. That’s good.”
Keystone uses water from the Roberts Tunnel, he said.
“It’s already there – the water we’ll use out of the Roberts Tunnel is in Dillon Reservoir,” Testwuide said. “It’s already stored. It’s just kind of like turning on the tap, so we don’t have to depend on stream flows.”
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