KRRC moves ahead with removing the Klamath River dams after the latest FERC filing.
On May 2, the Federal Energy Regulatory Commission (FERC) approved the Klamath River Renewal Corporation’s (KRRC) plans and schedule for removing Iron Gate Dam and J.C. Boyle Dam, giving the company its final authorization before work can begin in earnest.
KRRC’s lead contractor for the dam removal project, Kiewit, proceeded with the work on Monday, May 13.
Iron Gate and J.C. Boyle are the two earthen embankment dams that require extra care to be removed.
The concern is the potential for high flows to impound water against the dams while they are being removed, creating a potential for a breach and failure.
In the case of Iron Gate Dam, this concern is exacerbated by the flow restrictions that exist with the tunnel at the base of the dam, now being used to bypass all flows around the worksite.
KRRC has had to explain to FERC what it would do if this tunnel somehow became blocked or obstructed.
While flows are being diverted through the tunnel, Kiewit can now remove the dam itself.
Removal of Iron Gate Dam requires moving roughly a million cubic yards of rock, dirt, and sand. Approximately one-fifth of the removed material will be used to refill the cut for the dam’s spillway. The remainder will be hauled to the original nearby Borrow Pit.
Under KRRC’s ideal schedule, the removal will be completed by the end of September.
Copco 1, the oldest of the dams, is a concrete structure, which has allowed demolition to begin earlier.
In early April, during demolition of the power intake structure, a blast caused concrete rubble to partially block the new low-level outlet tunnel, causing the reservoir to begin to refill. KRRC’s contractor, Kiewit, mobilized equipment to the dam’s base to remove the debris and clear the outlet.
In response to this incident, KRRC committed to having its contractors “Perform smaller blasts and reduce powder factors to start with and build up to larger as necessary based on performance.” KRRC also agreed to have equipment operators on standby for each blast.
The following week, on April 11, Kiewit blasted the intake to the lower diversion tunnel, which was initially used during the dam’s construction. The blast did not fully open the tunnel, requiring Kiewit to perform further mechanical excavation.
On April 18, the diversion tunnel was finally opened, allowing river flows to be fully diverted around the dam site.
With the dam site dewatered, crews blasted the gates and superstructure off the top of the dam the following week. On the dam’s downstream side, work on demolishing the powerhouse continued.
“Mass dam removal blasting is expected to begin in early May,” KRRC reported in a May 9 filing to FERC.
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Article by, Moss Driscoll, KWUA Director of Water Policy for Basin Ag News, May 2024.
Cover photo caption: Aerial view of Copco 1 dam after the blast to clear and remove the spillway piers. Image: KRRC FERC Filing, May 9, 2024.
