Sean C. Morgan
Of The New Era
Foster Dam Road will close Thursday, Nov. 13, and is expected to remain so until Jan. 15 while contractors work on repairs to the first of the four spillway gates at the dam.
Work on the dam’s northernmost spillway gate, Gate One, is expected to begin Thursday.
During the summer, the Corps discovered that the structural members, the beams between the gate and the trunion bearing, which acts as a hinge, have been warped and twisted, either by the forces of the lake or friction in the trunions causing the gates to open unevenly.
All four gates are in need of repair. Initially, the Corps will repair Gate One. It will repair additional gates later, but officials anticipate being able to keep the lake at full pool next summer by inserting “stop logs” behind the gates as each is repaired.
The U.S. Army Corps of Engineers, began letting water out of Foster Lake through Gate Two last week in preparation, said Public Affairs Specialist Amy Echols. The lake will drop to an elevation of 604 feet, the top of the spillway, to allow the contractor to repair Gate One.
Gates Three and Four, the southernmost gates, will be used to pass water through during November and December during the construction. With the water so low, the powerhouse is unable to function, so the turbines are offline and are undergoing maintenance and inspection.
“We should be in good shape to handle rain events,” Echols said. The two powerhouse turbines can be used to bypass water if necessary while Gates Three and Four will remain cracked open.
“We’re looking forward to getting to work and getting things back on track,” Echols said.
The Corps held public meetings in Sweet Home and Lebanon two weeks ago. Some 35 people attended the Sweet Home meeting, Echols said. About a third were interested in the project itself, the engineering and the “wow factor,” and others were concerned about water flows, related to the project and related to development along the South Santiam River.
The Corps does not control the downstream development, Echols said, but the Corps referred the visitors to the proper agencies, including the city and county.
About a dozen people attended the Lebanon meeting, and they were all primarily concerned about downstream flows and flood control, Echols said. What happens downstream “completely depends on inflow” into Green Peter and into Foster, particularly the South Fork of the Santiam River, which will be flow through freely while the dam is being fixed.
There is no snow pack yet, and there hasn’t been much rain, she said, and the Willamette projects were running 3 percent below their rule curves as of Friday.
“We should be in good shape to handle rainouts,” she said.