do they lower the lake to this level every year?
We get lots of business from Folsom towards the end of the season from people wiping out their drives and under water gear.
Racer
Is there any good reason the dam road is closed?
State-of-the-art spillway planned for Folsom Dam
By: Roger Phelps, The Folsom Telegraph
Some 12 years after a break in a spillway gate at Folsom Dam posed flood danger for city residents, a new spillway project is planned to start within weeks, designed to slow the rise of Folsom Lake during storm seasons.
At a cost of $683 million, the U.S. Army Corps of Engineers will build the structure beginning in mid-December. It will be placed around a third of the way down the 450-foot-high dam, in order to spill early, at times when the lake is still filling, said Jeff McCracken, spokesman for the federal Bureau of Reclamation, dam operator.
"You move the 'overflow' down about 150 feet," McCracken said. "It will allow us to reach downstream channel capacity - 130,000 cubic feet per second - when the lake is lower."
Lake capacity is around 44 billion cubic feet of water.
In July 1995, a spillway gate on the Folsom Dam broke open as it was being raised, allowing billions of cubic feet of water to course past the broken gate before it could be repaired. The escape rate was more than 40,000 cubic feet per second, according to published reports.
Some flooding occurred. Folsom officials didn't take the failure lightly.
"We went and testified to Congress," said then-Mayor Steve Miklos. "The bureau said car traffic caused vibrations (that weakened the gate)." At another point, the bureau blamed a design flaw, effectively shifting the onus to the Army Corps design engineers, according to a report published on the "Wonders of the World" Internet site. "After an investigation and several hearings, it came out that poor maintenance was at fault," Miklos said. "(The bureau) had used the wrong grease, and metal was deteriorating."
Friction reduced the strength of large metal pins in the Folsom Dam spillway gate and caused the gate to break upon opening, the Internet report states.
In that context, the Army Corps this year put considerable effort into assuring against a repeat incident with the new project, said Chuck Rairdan, project engineer.
"Certainly, we learned a lesson from that break," Rairdan said. "We've looked at other gate configurations and we did new, additional design work. We've reached out to international experts. The state of the art has advanced since the original gates were designed. We have high confidence in the new design."
When the gate broke in July 1995, enough fresh water poured down the American River into San Francisco Bay that salmon and striped bass were fooled into thinking that autumn had arrived. The fish began their annual fall migrations about two months ahead of schedule.