The rains of May have continued into June and drastically improved irrigation supply in McPhee Reservoir.

Low winter snowpack had led forecasters to believe that the reservoir would not fill enough for a full irrigation supply.

In early May, farmers were told they would receive just 10 inches per acre, less than half their full allocation of 22 inches.

But record rain and snow in May bumped up snowpack and charged the Dolores River, which feeds McPhee.

As of Friday, full-service irrigators were told to expect 21 inches per acre, said reservoir manager Mike Preston.

"The rains made a really big difference in irrigation supply," Preston said. "Demand on irrigation started off slow because it was supplemented by Mother Nature, and that works to stretch supplies further into the season."

Significant shortages are no longer forecasted. Irrigators, the Ute Mountain Ute tribe, and the fish pool will all get close to their full allocation.

Montezuma Valley Irrigation Co.'s water rights out of McPhee are being met. And municipal water for Cortez, Dove Creek, and Towaoc will be fulfilled. In a shortage situation, municipalities continue to get their full allocations.

Between May 4 and June 2, the reservoir level rose 18 feet, and more runoff is on the way, which may bump it an additional 27 feet.

Reservoir managers are still working off forecasted runoff models, which look favorable. On June 3, the Dolores River at Dolores peaked at 2,800 cfs.

"Due to the rain, we got high river flows, filling the reservoir before it got hot. Once it does get hot, the river will drop, then there will be another peak when the higher altitude snowpack melts off," Preston said.

There are no plans this year for a whitewater boating release below the dam. However, the strong start bodes well for a carryover supply of water for next year.

A carryover supply improves the chances that the reservoir will fill next year with enough additional water to provide a boating release for the Lower Dolores River canyon. The last time that happened was in 2011.

jmimiaga@cortezjournal.com