Warm days are expected to keep Big Wood and Little Wood river flows elevated this week as they continue to hover around flood stage. Late season precipitation and a more normal spring runoff are feeding higher flows that have tapped into the higher elevations' snowpack.
Substantial flooding last week in Carey resulted from heavy rains in early May that were well above average. Mayor Rick Baird said river banks needed to be reinforced and sandbags donated by the county are still important tools for helping to stem the tide flowing through the city. However, by all accounts, there were no injuries and relatively little damage. Other than flooded fields and basements and considerable time and energy spent clearing debris from canals and bridges, Carey residents were managing the flood conditions well, Baird said.
"We had to chase a couple of wake boarders away from a couple of bridges," Baird said, smiling and amicable, but showing signs of fatigue.
Along the Big Wood River, banks were breached in several locations, but major flooding along the river corridor was avoided.
Magic Reservoir also is filling to unexpected levels. Chuck Turner, the county's disaster services coordinator said the reservoir is fuller that he has seen it in many years.
"We're down below flood stage," Turner said, commenting on risks of continued flooding in the river courses leading to the reservoir. "Water levels vacillate. It's not a smooth decline."
Over the past week, water levels have been highest in the mornings, tapering off by the end of the day, only to rise again the next day. Flows are expected to stay elevated for another week as warmer weather causes snow stored at higher elevations to melt more quickly.
At the Garfield Ranger Station SNOWTEL site, an automated precipitation measuring station located at 6,560 feet in the Little Wood basin, the average monthly precipitation is 2.4 inches. So far this month, the total is 7.5 inches. In the 24-hour period from May 16 to 17, alone, the total annual precipitation jumped two inches.
"A lot of other sites were like that throughout the basin," said Boise-based Natural Resources Conservation Service (NRCS) Water Supply Specialist Ron Abramovich. "One to two inches throughout the basin was pretty common."
At the Garfield site nine inches of precipitation was recorded from October to March. Since mid-March nearly 12 inches has fallen.
"It shows how dry we were most of the winter," Abramovich said. "When the weather pattern turned wet, unfortunately, a lot fell as rain. We did get some snow, which will delay the runoff. With rain the runoff will come out instantly, but at higher elevations the snow is still there."
Abramovich said snow water will reduce drought conditions in the short term, making the irrigation season better than last year because there will be more water in Magic Reservoir and the Little Wood Reservoir is expected to remain full at least until the beginning of July. Magic reservoir is still expected to fill by an additional 75,000 acre-feet.
At a higher SNOWTEL site on Smiley Mountain (9,500 feet) at the divide between the Big Lost and Little Wood drainages, instruments calculated a peak of 20.9 inches of snow water on May 19, it was down to 17 inches by Tuesday.
The increase in snow water will help sustain river flows a bit longer, Abramovich said. "If we go back and ignore the rain, it paints a totally different picture. This is helping tremendously with the drought.
But, he added that longp-term drought problems will not be alleviated.
"We will continue to have low springs in wetlands areas (and) low soil moisture. Aquifers are still low. We need a couple of wet years in a row," he said. "Overall, it's just going to be marginal. Stream flow peaks went up and went down pretty quickly, but we have snow to sustain a little longer."
The Blaine County Road and Bridge crew was busy with regular maintenance on Trail Creek Road, but had some extra work in Carey working on a bridge in Muldoon Canyon and another in Warm Springs, said Dale Shappee.
"I hope we've seen the last of it," Turner said. "But, that all depends on the snowmelt."
Quick spring runoff following heavy rains has filled Magic Reservoir on the Big Wood River beyond expectations. Predictions for continued snowmelt runoff indicate that the reservoir may fill by an additional 75,000 acre-feet. The view above is from the eastern entrance to the reservoir. Photo by David N. Seelig
