Iron Gate Dam Reservoirs Lowered on Klamath River

The Iron Gate Dam. Photo courtesy of Michael Wier/California Trout, via the American Society of Civil Engineers.

The largest dam removal in U.S. history is underway, with the lowering of dammed reservoirs on the Klamath River in Oregon.

Members of the Yurok Tribe were on hand to witness the first big surge of waters on Jan. 11, as Oregon Public Radio reported on opening of a 16-foot-wide bypass tunnel at the base of the dam, releasing the flow of water darkened by pent-up sediment that also surged through.

The Iron Gate itself is an earth embankment dam. The lowering of Iron Gate and two other reservoirs on the Klamath river will make way for removal of three remaining hydroelectric dams that are part of the Lower Klamath project in Northern California and southern Oregon.

The report from Oregon Public Radio on NPR’s “All Things Considered” program hailed the removal of major dams along the Klamath River as a win for local tribes.

NPR reported noted that a massive die-off of Chinook salmon in 2002 –  an estimated 34,000 to 78,000 fish – prompted increased activism around having the dams removed.

Meanwhile, advocates for additional dam removal are eyeing four dams on the Lower Snake River in Washington as the next big dam removal project.

Shari Witmore, a biologist with NOAA Fisheries, noted that removing barriers would open up 76 miles of coho habitat and over 400 miles of Chinook habitat.

If modeling is accurate, as many as 80% more Chinook salmon could return to the basin within 30 years after dam removal, and ocean harvest could increase by as much as 46%.

“Once we restore that, we put this basin back together,” Witmore told NPR. “That creates a lot of resilience over time with climate change, and it buffers against multi-year droughts.”