Reservoirs high stakes 'cat & mouse' game with Mother Nature

While an abundance of water is making its way into California reservoirs, federal, state and local dam operators are worried about two uncontrollable things: more atmospheric rivers and a quick melt of the snowpack in the mountains.

LAKE SONOMA, Calif. - While an abundance of water is making its way into California reservoirs, federal, state and local dam operators are worried about two uncontrollable things: more atmospheric rivers and a quick melt of the snowpack in the mountains.

Even though they're not completely full, many California dams have begun releasing water, just to make sure they have space for a lot more to come.

For instance, Lake Sonoma is releasing a lot of water into the Russian River on its way to the Pacific Ocean at Jenner.

"This is good to see though, it's, I've never seen them let out this much water, so that's good," said Rick Deaton.

The Deatons have come here for decades.

Lake Sonoma already has all the freshwater it needs and then some. But the "then some" is taking up space reserved for coming storm inflows to keep the water from uncontrollably running out of the emergency spillway.

Sister reservoir Lake Mendocino was the first to begin releasing excess water back in mid-January.

Before the rains, California's second-largest mega reservoir Lake Oroville looked like a small river in a wide, gaping canton. As of Friday, it is a nearly full, water bonanza.

The reservoir began releasing water on March 10. A week later, it was releasing so much water that nearby roads were closed as a precaution.

East Bay MUD has two big Sierra reservoirs; Comanche and Pardee.

"Our Pardee Reservoir, which is the main reservoir we get our drinking supply, is a hundred percent full. We're spilling a little bit over the top of that as it's designed to do," said EBMUD spokesperson Andrea Pook.

Higher up the mountain is Camanche Reservoir, which is 90% full, but with enough space to take a lot more water. It will also have to deal with the massive snowpack as will all snowmelt feeds reservoirs as it warms up.

"For East Bay MUD, we have a snow gauge that tops off at 165 inches, and it's buried," said Pook.

For all dam operators and those downstream, it's a high-stakes game of cat and mouse.

"We're playing that game now where the Army Corps of Engineers whether we have enough water or not enough water. Part of the problems in the past was, that game didn't work every time," said Deaton.

As we learned from the 2017 Oroville Dam disaster where the water actually came up over and damaged the dam, this is a game of "cat and mouse" that the managers of dams dare not lose. And, with all that snow up there, it's a real threat to them.