South Santiam River water has been running freely through three gates at Foster Dam while repairs continue on the fourth gate, but U.S. Army Corps of Engineers officials say there have been no flooding problems related to the project.
The dam has been offline since November in an attempt to repair one of the four damaged gates in time to give the Corps the ability to use the dam for flood control as the rainiest part of the winter season gets under way this month.
Over the past couple of weeks, the Corps has been holding water back at Green Peter, Public Affairs Assistant Chief Amy Echols said. The Corps started releasing water from Green Peter following Thursday’s storm to increase its storage capacity for more heavy precipitation.
The Corps’ reservoirs in the Willamette Valley quickly filled to about 26 percent of their overall flood storage capacity in the past week as engineers and operators managed the 13 dams on six rivers, Echols said.
Another storm hit Sunday night, and another is expected midweek, according to the National Oceanic and Atmospheric Administration. As of Monday, NOAA was predicting that high pressure would set in this weekend, keeping Oregon mainly dry for awhile.
Erick Petersen, operations project manager for the Willamette Valley Project, said the Corps’ system of dams provide protection from the risk of flooding for communities in low-lying areas of local river systems.
“We are providing relief to Salem, Albany, Harrisburg and other communities in the lower area,” Petersen said. “To get an idea of how much flooding is being reduced by the Corps’ dams, consider that at 10 a.m. today (Friday), we were releasing about 22,300 cubic feet per second, or only 20 percent of what came at us. Our reservoir at Blue River was filling at 1.5 feet per hour.”
Echols said that because of Foster’s limited storage capacity, more water than usual has been held back at Green Peter.
“We have a lot to be released at Green Peter,” she said.
About two weeks ago, the level at Green Peter was at about 924 feet above sea level. On Friday, it was at 943 feet, about 39 percent full. Monday night, it was at 959.33. During the summer, the lake reaches more than 1,000 feet. The Corps was
scheduled to significantly draw down Green Peter over the weekend.
“We’re drafting basically to get ready for the next series of events,” Echols said. “There’s no storage issue at this point. We just have to draft down.”
The banks of the South Santiam at Waterloo were full last week, Echols said, but it remained below flood stage. It was the same way downstream, although a couple of areas did have flood warnings, including the Santiam at Jefferson.
Crews have continued to work on spillway gate one through all of the weather, Echols said. “They took a couple days off for Christmas, and that was it.”
The Corps is still planning to have the job finished by Jan. 15, reopening Foster Dam Road, she said.
The Corps must replace “trunion” bearings and deformed structural members in each of the dam’s four gates. The Corps discovered the gates were damaged during an inspection last summer. It briefly drew down the lake to slightly under its winter pool level, 613 feet, to conduct additional inspections and grease the trunions.
As funding becomes available, the Corps will continue to repair gates, which will require additional closures of Foster Dam Road. The Corps has purchased enough stop logs to hold Foster Lake at full pool next summer, even during repairs, if everything goes as planned.