Tahoe’s water level about to start declining

By Jeff Delong, Reno Gazette-Journal

Lake Tahoe likely reached its maximum level for the year Tuesday and will now start a steady drop in further evidence of a dry year.

Nudged up incrementally by Monday’s rain and snow showers, Tahoe reached a level of 6,227.66 feet above sea level Tuesday. That’s probably as high as it’s going to get.

“This very well may be the peak,” said Chad Blanchard, chief deputy water master.

Lake Tahoe is at its peak this week in regards to the amount of water. Photo/LTN

The lake likely will stay at its current level for a few days or so as inflow from melting snow roughly equals the amount of water evaporating from the lake.

Once evaporation rates exceed inflow — and that could happen quickly, particularly under hot and windy conditions — things will change.

“Then it will drop,” Blanchard said. “The lake will start its long descent through the summer.”

The lake reached its pivot point nearly two months earlier than last year. An epic winter of 2010-11 layered the Sierra in drifts of snow that stuck around under the influence of a cool spring.

Tahoe didn’t stop rising until Aug. 1, topping out at 6,228.42 feet in what was its sixth most impressive rise in over a century.

As stands to reason, the lake reaches its maximum level early during dry years such as 1992, when it topped out May 17 at 6,221.87 feet. During particularly wet years, rising doesn’t stop until much later. In 1965, it didn’t stop rising until Aug. 17 at 6,228.87 feet.

This year is definitely on the drier side. A sub-par winter ended with an April 1 snowpack at only a little more than half of where it should have been for that time of year. The snow’s been melting since, and “there’s very little left,” Blanchard said.

The contrast to last year is dramatic.

“Last year was close to the latest I’ve ever seen it,” Blanchard said. “Last year was about as late as it gets and this year was pretty darned early.”

How much the lake drops over the course of the summer will be determined by weather conditions, but the lake will probably go down 2 feet or so, still staying roughly 2 feet above its natural rim.

When full to the maximum legal limit, 6 feet of water above the rim are stored by the dam at Tahoe City for downstream use by Reno-Sparks and Nevada agriculture.

That means there is plenty of water for municipal use, said Bill Hauck, water supply coordinator of the Truckee Meadows Water Authority. The area’s primary water purveyor serves about 93,000 homes and businesses across the greater Reno-Sparks area.

“Our water supply is in really good shape,” Hauck said. “We should have full river flows throughout the year and into next year.”

Tahoe and Boca reservoirs, which combined store the bulk of water that flows down the Truckee River for local use, are still at roughly 75 percent of capacity because of the strong winter of a year ago, Hauck said.

“It’s not anything like last year,” Hauck said of current conditions. “The snowpack and runoff are pretty meager compared to last year, but those reservoirs really save our bacon.”