NorCal Reservoirs Approach Capacity with More Rain and Snow in the Forecast

Shasta Lake

At the beginning of May, Northern California reservoirs were already sitting at historic levels. Then came the unexpected stormy weather that saw historic rain in the valley and almost 2-feet of snow in the mountains.

Now, as the major lakes in NorCal approach capacity, the question remains – where will all this water go?

As of May 22nd, the four major NorCal reservoirs sit at or above 95 percent capacity, a sharp rise of 4 percent in just two weeks. Here are the current statistics:

Shasta Lake – 97% capacity – 113% historical average

Trinity Lake – 97% capacity – 114% historical average

Lake Oroville – 96% capacity – 115% historical average

Folsom Lake – 95% capacity – 117% historical average

Snow sensors across the Sierra Nevada indicate that snowpack is at 155 percent of historical average and 10 feet of snow remains in some Tahoe areas. During the road clearing process in Lassen Volcanic National Park, officials measured snow walls at 28 feet.

There’s so much water in NorCal and there is still much more on the way. Another storm is expected to hit the mountains during Memorial Day Weekend and, in some areas, is forecast to last through the end of the month. During May, snowmelt is typically the cause of rising reservoirs. But this year, the wave of snowmelt flowing down NorCal waterways may not come until late-June.

Water officials are keeping a close eye on water levels and releasing water at high rates in order to avoid flooding. But with already high reservoir levels, increased flows could mean flooding on rivers and streams. On top of that, the brand-new Oroville Dam spillway may need to be used for the second time this year, putting locals near the lake on high-alert.

Lake Oroville is nearly full. Photo: Explore Butte County

“I’m very concerned about the lake levels,” District 1 Supervisor Bill Connelly said Tuesday during the Department of Water Resources Board of Supervisors meeting. “Lake Oroville is being run in an antiquated and linear matter. (DWR’s) priority seems to be water delivery instead of public safety. We need to move into the next century. We’ve had warm rain on snow before, and if we have warm rain on snow right now, it would be one of the worst disasters in the history in the state.”

The DWR remain adamant that it has no plans to release more water from the Oroville Dam spillway, a claim that has locals skeptical.

The winter, and subsequent wet spring, of 2019 has been great to relieve Northern California of its drought and qualm fears of another historic fire season. But how much water is too much? We may find out soon enough.

Active NorCal

Telling the Stories of Northern California

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