Water levels rising, snowpack shrinking
TRUCKEE/TAHOE ” It’s already looking like a record-setting May for precipitation around Lake Tahoe.
A four-day rainstorm that started May 1 deposited 3.5 inches of water at the measuring station in Tahoe City, making it already the fifth-wettest May in the last 100 years with much of the month still to come, according to Chief Deputy Water Master Chad Blanchard with the U.S. District Court Water Masters Office. Average precipitation in Tahoe City for the month of May is 1.2 inches.
“All this rain was rare for this time of year, and very helpful,” Blanchard said. “We’re still behind, no matter what. The snowpack today is 48 percent of average compared with other years at the same date. But again, because we had that direct rise in a few days, we’re much better off than we were.”
The recent rains have delayed runoff forecasts usually published by area water agencies the first week in May. Lake Tahoe, for example, raised .34 inches, more than a third of what was expected for the entire runoff season, from mid-April through May.
“The big question is, ‘How much of that rise came from new precipitation versus how much of that rise came from melting,'” Blanchard said. “This obviously will change the runoff forecast somewhat. We gained snow at the upper elevations, but it probably doesn’t match what we lost at the lower elevations.”
Blanchard added that the wet soil should mean more snow meltoff is reaching area rivers and lakes, instead of evaporating or soaking into the ground.
Local aquifers are filled and ready as well. The Truckee Donner Public Utility District aquifer, which supplies water to most of Truckee, is recharged and back to where it is every year, said Ed Taylor, the water utility manager for the district.
“We’ve got sufficient water supply,” Taylor said. “We just want our customers to use water wisely. Don’t waste it.”
Squaw Valley Public Service District’s operations manager reports the recent rains put its aquifer at full, and asks users to still conserve water. They are not looking at any drought restrictions at this time.
While this temporarily decreased the fire danger in the region, fire authorities are still asking for caution and for folks to prepare for a rough fire season.
Elevation levels are increasing rapidly at Lake Tahoe after five days of rain and additional snowmelt caused by warm temperatures, according to the U.S. Geological Survey. The rim reached 6,224.07 feet above sea level on Wednesday, still below the historic average lake level one foot higher and one foot below the level last year on May 5.
Lake Tahoe’s overflow into the Truckee River, the lake’s only outlet, has slowed near Truckee from 838 cfs to 627 cfs this week after the rains last week sent the river surging, according to the state’s Department of Water Resources. But water authorities say the river is looking normal for this time of year, but with a depleted snowpack, water levels are expected to remain below average all summer.
Donner Lake levels are decreasing after peaking last weekend. The current rim is at 5,934.78 feet above sea level, a little more than a foot higher than it was on April 26, but a fraction less than where it was last Friday, according to the state’s Department of Water Resources.
Stampede Reservoir’s rim is showing some of the fastest growth after last week’s rainstorm, reaching 5,904.54 feet above sea level, a 3-foot increase from last Friday. The lake levels have increased more than 7 feet in the last month, according to the state’s Department of Water Resources. This is still well below last year’s May 5 elevation level at 5,921 feet.
Boca Reservoir near Truckee is storing more than 1,000 acre feet more than it was a month ago, showing consistent gains due to runoff and rain. It’s elevation is at 5589.75, a slight increase since May 1.
As of May 5, Prosser Reservoir was storing 22,300 acre feet of water, up from 20,300 on May 1 and 11,300 on April 13. It had been growing about 500 acre feet per day based on runoff and rainfall.
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