Removal of the Copco 2 dam, one of four Klamath River dams that will be coming down, is still on schedule to be removed this summer.
Mark Bransom, CEO for Klamath River Renewal Corporation (KRRC), said projects preparing for removing Copco 2 are on schedule with the actual removal planned between June and October. The other three hydroelectric dams — Copco 1, Irongate and John C. Boyle — are planned to be removed in 2024 making the project the largest dam removal effort in U.S. history. A report by a Medford television station caused some confusion when it indicated that no dams would be removed until next year.
“We’re optimistic we can stick to the schedule,” Bransom said of removing Copco 2 this summer and the other three dams in 2024. “Everything is clicking well. We have all the necessary approval and authorizations to proceed.”
Copco 2 is located below Copco 1 and the Copco Reservoir and above the Iron Gate Reservoir and Iron Gate Dam. Bransom noted a series of actions are being taken in advance of all four dam removals. For Copco 2, pre-removal work includes mobilizing and setting up offices, constructing road and infrastructure improvements, installing a 24- by 60-foot culvert at Fall Creek, installing a 260-foot prefabricating truss bridge over the Klamath River at Daggett Road, installing 3,300-feet of 24-inch steel, waterline for the city of Yreka, removing 13 recreational facilities at all four reservoirs, and drilling and blasting a 90-foot long 10-1/2-foot tunnel at the base of Copco 1 dam.
Other work includes constructing new access roads to both Copco dams, demolishing an existing concrete diversion dam, and removing existing on-site residential buildings.
According to the construction overview, Copco 2 will be removed by drilling and blasting with the removal projected to be completed this fall. A restored river channel will be built through the existing dam footprint.
In addition, during the next several months reservoirs behind the existing dams will be simultaneously drawn down and other projects completed before the dams are removed. The pre-removal work will include demolishing 100,000 cubic yards of concrete, 1.3 million cubic yards of excavation, 70,000 cubic yards of “drill and shoot,” and 2,000 tons of steel demolition. Resource Environmental Solutions (RES) will revegetate the impacted areas with native plant species. More than 11 billion native seeds have already been collected and propagated. Monitoring to ensure revegetation success, control invasive species and other restoration activities will last several years, until about 2030.
Based on the current schedule, the J.C. Boyle Dam will be the second dam removed, followed by Copco 1 and Irongate. Restoration of the reservoirs and tributaries will begin in early 2024. The four dams have a combined height of 411 feet. Copco 2, which became operational in 1925, is the shortest of the four with a hydraulic height of 27 feet and structural height of 63 feet.
The construction overview indicates the four dams impound about 15 million cubic yards of sediment. “When the reservoirs are drained, about half that sediment, or estimated 7 million cubic yards, will wash downstream. The project needs to drawdown the three largest reservoirs simultaneously in January and February 2014 to limit the salmon spawning impact. Then dam removal will be completed by the middle of October when the next round of adults (salmon) come back upstream.”
Cost for the dam removals and restoration activities are estimated at $450 million. The former dam owner, PacifiCorp, is providing $200 million, which was collected as ratepayer surcharges, while the state of California is providing the remaining $250 million from voter-approved bond funds allocated for the project. PacifiCorp and the states of Oregon and California have also agreed to contribute up to an additional $15 million each — or another $45 million — to cover any unanticipated cost overruns. If the costs exceed the contingency, the states and utility have agreed to cover such overruns.