California Forum

The year drought turned to deluge

History is best not forgotten, especially when lives could be at stake.

Earlier this month, operators of the federal dam at Folsom Lake significantly increased releases into the American River, even though California’s water crisis is far from over.

Though the reservoir was sitting at 40 percent of capacity, a manual drawn up in 1987 by the U.S. Army Corps of Engineers required the action, The Bee’s Ryan Sabalow, Phillip Reese and Dale Kasler reported last week. Some regional water managers and experts frowned that too much water was being released when California is still gripped by drought.

Perhaps the decision is conservative. Certainly, the manual ought to be updated. But Folsom Lake is like a teacup in a massive watershed, and it can fill fast, as those of us who were around 30 years ago this month know. One of the worst deluges ever recorded in this region struck in February 1986. The flooding could have been far worse.

“Ferocious storms were testing the limits of Northern California’s dams and rivers,” Tom Philp, then a member of this editorial board, wrote in 2006, commemorating the decisions made in 1986.

Officials had been preparing for drought when an extraordinarily strong Pineapple Express weather pattern was developing in the Pacific. And then it arrived.

At Bucks Lake in Plumas County, 49.44 inches of rain fell in 10 days. A temporary dam built on the American River in anticipation of the Auburn Dam that never was built failed. Huge amounts of water cascaded downstream into Folsom Lake.

As Philp recounted, regional leaders of the Army Corps and the U.S. Bureau of Reclamation and the director of the California Department of Water Resources collectively decided to release more water from Folsom Dam than had ever been released before.

On Feb. 19, 1986, more than a million gallons per second rushed down the American River. People prayed that levees would hold. Most did. Sacramento was spared, though others were not as fortunate.

A new manual for Folsom Dam’s operation was drafted. The document written in 1987 before climate change became widely accepted ought to be rethought, and that won’t be easy.

No one knows what the new normal is. Perhaps the storms of years to come will be so warm that there will be little Sierra snowpack. Maybe this relatively wet year is unusual and California will return to a dry year in 2017. Maybe we’ll be inundated. Take a guess. Pin the tail on the donkey.

Once the new spillway being constructed at Folsom Dam is completed in 2017, more water can be stored. But that won’t do much good this year if big storms hit. It could be that we’ll wish after the rainy season has passed that dam operators had withheld water that flows downstream today.

But today, officials at the Army Corps and Bureau of Reclamation are being cautious, so they don’t need to repeat what their predecessors did 30 years ago in a heroic effort to avoid what could have been a calamity.