The potential for gate failures at two aging dams led El Dorado Irrigation District officials to declare emergencies at Caples and Silver lakes.
The move, approved during a special meeting Tuesday, is intended to hasten repairs to gates that control water releases from the two dams, built in the 1920s.
"We do not have a dam failure," said Jake Eymann, an engineer and acting co-manager of the district's hydroelectric division. But he said underwater inspections June 10 and 11 disclosed serious deterioration of gates and other devices that control water storage and releases at the lakes.
Caples Lake in Alpine County and Silver Lake in Amador County are a few miles from each other, off Highway 88. They are part of hydroelectric Project 184, a system of lakes, canals and a powerhouse that the district purchased from Pacific Gas and Electric Co. in 1999.
Eymann said employees reported difficulties operating outlet valves at Caples Lake beginning in 2006. Last month's inspections by divers equipped with cameras revealed that brass seats for a lower slide gate were missing, resulting in excessive leakage and vibration, according to a staff report.
A video of the underwater inspections presented during the board meeting showed corroded metal, and a dislodged and bent trash rack, designed to catch debris.
At Silver Lake, Eymann said, staff members were not aware of problems, but they undertook the inspection "to build up a map of the facility."
The inspection found that steel bracing for the outlet tower had failed due to corrosion and gate stems were severely corroded, he reported.
At Caples Lake, Eymann said, staff members will avoid operating the lower of two gates, at a depth of 64 feet, because it is on the verge of failure. If it failed in the open position, it would result in the uncontrolled release of the water stored in the lake. In the summer, it would create unseasonably high downstream flows, he said.
Eymann said staff members sought the declaration of emergency to speed the repair process. The board's action, under state law, allows the district to move more quickly by contracting for services and equipment without competitive bids. It also exempts the project from California Environmental Quality Act review.
Staff members said they will have to obtain approvals for the work from the Federal Energy Regulatory Commission and the state Division of Safety of Dams.
District directors, as well as community representatives on the Project 184 Ecological Resources Committee, expressed frustration that they were not informed earlier of the potential problems, given that difficulties operating the gates at Caples Lake were noted two years ago.
Director John Fraser questioned whether problems that developed over a period of years met the legal definition of an emergency.
District counsel Tom Cumpston said emergency conditions can result from a series of occurrences. In this case, he said, the conditions at the dams pose a risk to public safety, drinking water storage and the environment. They also threaten the district's ability to maintain lake levels and flows out of the lakes as required under its federal license to operate Project 184.
"We don't know when (the gates) would fail," Cumpston said, "but we know what would happen if they do."
Because many of the replacement parts may have to be custom made, Eymann said it likely will be at least a year before the repairs can be undertaken.
"Even expedited," he said, "this will not meet normal expectations for a quick project."
Director George Osborne said he was particularly concerned about losing needed water supplies when the lakes are drawn down for repairs.
Doug Barber, district ranger for the Eldorado National Forest's Amador Ranger District, noted that the Forest Service is working with the irrigation district to install a new boat ramp at Caples Lake. He said the Forest Service would try to coordinate the ramp project with gate repairs so that the lake would not have to be drawn down twice.
Staff members said they need to consult with contractors to determine the options for repairs. Steve Setoodeh, director of facilities management, said they would work with various interest groups to minimize the impact on water conditions and recreational uses.
Director George Wheeldon said he favored the emergency declaration to hasten the repair process.
"Treading water while we decide what to do is really putting a lot of people in jeopardy," he said. "I think we need to get the ball rolling."
