Winter bodes well for McPhee Reservoir
Farmers in better shape than last year; boaters, not as well
The Cortez Journal
The news for McPhee reservoir is better than last year for farmers, but again looks grim for a whitewater release for boaters below the dam.
An improving winter has put snowpack for the Dolores River basin at 89 percent of normal, based on a 30-year average. In January, it was at 73 percent of normal.
Three situations are working in favor for farmers in 2014. One silver lining is that a wet fall recharged soil moisture in the mountains, which translates to more runoff into the river in spring.
“Last year, a lot of the runoff was absorbed into the ground because it was so dry. This year, we won’t have that issue, so the rivers and creeks will fill the reservoir more,” said Mike Preston, general manager for the Dolores Water Conservancy District.
Second, recent snow storms tracking in from the south are stabilizing the snowpack, which gained a good base in early December.
“It is compressed well, and is less susceptible to wind sublimation and evaporation,” Preston said.
In 2013, full-service irrigators received just 25 percent of their full allocation of 22 inches of water. The driest year since the reservoir filled in 1987 dramatically reduced harvests of the region’s alfalfa cash crop from the usual three to four to just one.
Managers expect a minor turnaround for 2014 based on current conditions and forecasts by the National Resource Conservation Service and the Colorado River Basin Forecast Center.
Because of good water content in the snowpack, DWCD managers expect farmers to receive double their allocation from last year even without more snowstorms for the remaining six weeks of winter.
“If the rest of the winter goes dry on us, our most pessimistic forecast would be a 50 percent allocation,” Preston said. “The snow-water equivalent in the Dolores Basin is at 9.8 inches, enough to recharge the reservoir more than last year.”
But more is needed, he said, and exactly how much is tantalizingly close to a normal year.
Just 4 to 5 more inches of snow-water equivalent would put the estimated allocation for full-service users of the Dolores Project at 100 percent.
Six inches of snowfall equals an inch of snow-water equivalent.
“Two feet of additional snowfall in the next six weeks would put us at, or near, full allocation,” Preston said. “Whether it comes all at once, or 4 inches per week, we’re that close.”
The forecast for boating on the lower Dolores is looking shallow however.
A lack of carryover storage due to last year’s low snowpack, hot summer, and high irrigation demand is to blame.
“We drew down all of the active storage, and had to start over,” Preston said.
“There is just not enough time left in winter to get the amount of snow that would allow for a downstream boating release.”
Rafting releases often depend on the previous years’ reservoir storage levels. Carryover storage of 20,000 to 30,000 acre-feet followed by an average winter typically translate to a whitewater boating season below the dam.
“If we get carryover storage this year, in 2015, boaters will have a much better chance at a spill if there is average snowpack,” Preston said.
Between 2000 and 2013, there were eight years when there enough water to release downstream for a boating season on the Lower Dolores River below McPhee dam. Last year there was no release.