Lake Tahoe Reaches Natural Rim

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TAHOE CITY, CA - For the first time since 2009, Lake Tahoe will stop flowing into the Truckee River. Whenever it happens, it means we're in a dire water situation. Lake Tahoe Tuesday reached its natural rim, something that hasn't happened since 2009. From now, until we get a lot of rain, the Truckee River in Tahoe City will essentially stop flowing.

There is six feet of water storage on top of the natural rim of Lake Tahoe. It is water that took us years to save up, but now it is all gone. Water from Lake Tahoe is still flowing into the Truckee River, but it's next to nothing. What is usually a thriving waterway is now just a creek.

"The river will be losing it's flow, become mostly standing pools and things of that nature," said Mark McLaughlin, a Tahoe weather historian.

The lake has reached its natural rim, which means it has dropped below a point where it can feed the river.

"We really rely on 12-15 big storms and if a few miss us, it's hard to catch up," said McLaughlin.

Those storms did miss us this year and they missed us for the last three years. Our drought is concerning, but nothing new. The conditions on Tahoe have been far worse.

"In the mid '70s we were at the rim and the late '20s the early '30s," said McLaughlin.

The most extreme case was in the early '90s, when a several-year drought let evaporation take the lake 3 feet below the natural rim. More recently, the lake dropped below the rim in 2009.

"As far as we're concerned from a water supply perspective, there is no impact for us," said Bill Hauck, hydrologist with TMWA.

The lake hitting the rim is not a big concern for the Truckee Meadows Water Authority. Essentially, Tahoe been providing next to nothing for months now. This latest change has little effect.

"Over the last month, the flows have been just declining gradually; it has not been a major contributor to Truckee River flows for quite some time," said Hauck.

The Truckee Meadows has been getting its water from TMWA's drought reserves; we've used about 17 percent. There is plenty left for later years, but we don't want to use it. Instead, there is growing hope the lake replenishes itself this winter.

Hitting the rim is having little to no effect in Reno, but it is triggering an obvious change in Tahoe City. We could see parts of the Truckee dry up in Tahoe City, but as always it could change as quickly as the weather.