The wet February promised by weather forecasters so far has lived up to its billing, bringing enough rainfall to help fill dwindling Jackson County reservoirs but not in levels quite high enough to quell concerns for summer drought.
Strong upper Rogue River in-flows helped the lake surge from 10 feet below normal two weeks ago to more than 5 feet ahead of its normal filling schedule Tuesday, the U.S. Army Corps of Engineers reported.
The reservoir was so comfortably ahead of its filling scheduled that Corps regulators Tuesday upped releases to the upper Rogue for the first time since mid-September.
Those releases will rise again this evening to 2,500 cubic feet per second, the highest releases since mid-June as Corps hydrologists finally get back on track for filling Jackson County's largest reservoir for the 12th consecutive year.
"The rain helped a lot" says Laurie Nicholas, chief of the Corps' reservoir regulation section in Portland, which over sees Rogue Basin operations. "At least the reservoir is heading in the right direction."
The recovery has been less dramatic at Applegate Reservoir, which had been well over 30 feet shy of its filling schedule less than two weeks ago.
That kept the reservoir, on the Applegate River, from catching up as forecast this week and it remained more than 10 feet shy of its filling schedule Tuesday, Nicholas says. An updated forecast Tuesday predicts Applegate Lake will end February at 4 feet shy of the filling curve.
The filling curve is the schedule designed for hydrologist use to systematically fill each reservoir by May 1, providing enough stored water for planned releases meant to help migrating chinook salmon survive summer's hot water temperatures further downstream.
That left the two reservoirs collectively at 63 percent of full, according to the Corps.
"These two reservoirs are primarily rain-driven, so if we get the spring rain, we have a chance" to fill, Nicholas says.
That's not quite the case for the three reservoirs operated by the Talent Irrigation District, where Siskiyou Mountains snowpack not only helps fill Hyatt and Howard Prairie reservoirs each spring but also helps delay the summer storage draw-down.
"Snow is definitely like another reservoir for us," TID Manager Jim Pendleton says. "We definitely need more snow and precipitation to keep us out of the reservoirs."
The recent steady stream of wet storm fronts have helped rebuild rain levels but not so much the snow levels. The Rogue Basin was listed Tuesday at 50 percent of normal for precipitation, but with a snowpack of only 30 percent of average.
Pendleton says TID ended last year's irrigation season with a good carryover storage of about 60 percent of capacity at Hyatt and Howard Prairie high in the Cascades. But those reservoirs dropped and even with the recent rains Hyatt and Howard Prairie were both slightly over half full. Emigrant Reservoir near Ashland was just above one-third full.
TID on Tuesday began shifting water from Hyatt to Emigrant in preparation for capturing more high-elevation runoff, Pendleton says. After Tuesday night's front peters out today, another weaker front will move through Thursday, followed by a dry period, according to the National Weather Service.
Reach Mail Tribune reporter Mark Freeman at 541-776-4470, or email at firstname.lastname@example.org.