CALIFORNIA TROUT

Klamath River Dam Removal

Photo: Pusher, Inc.

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Project Facts

LOCATION

Iron Gate Dam

PROJECT STAGE

Complete

COMPLETION DATE

2024

Project Goal

Remove four dams — J.C. Boyle, Copco 1, Copco 2, and Iron Gate — from the Klamath River to eliminate the largest barriers to salmon and steelhead migration on the river, reopening more than 400 miles of historic spawning and rearing habitat blocked since 1917.

Project Summary

For more than a century, four dams on the Klamath River blocked salmon and steelhead from reaching hundreds of miles of the productive habitat their ancestors once relied on, while the reservoirs behind them bred toxic algae blooms and steadily degraded water quality downstream. This was a Tribal-led effort, and CalTrout spent 24 years working toward a solution, sitting at the negotiating table alongside Trout Unlimited, American Rivers, the Klamath Basin Coalition, the Yurok, Karuk, and Klamath Tribes, PacifiCorp, The Nature Conservancy, the Pacific Coast Federation of Fishermen's Associations, and the Salmon River Restoration Council.

That work culminated in the largest dam removal and river restoration project in U.S. history. PacifiCorp's FERC license was transferred to the Klamath River Renewal Corporation, which carried out the removals with funding from PacifiCorp and the State of California. In August 2024, the cofferdam at the former Iron Gate Dam site was breached, and for the first time in over 100 years, the Klamath ran free through this section.

The results came quickly. Within the first year, post-removal monitoring documented thousands of salmon returning to newly accessible habitat, evidence that this historic restoration is already delivering on its promise: healthier water quality, a river reconnected end to end, and a real path toward recovery for the salmon, steelhead, and Tribal communities whose lives have been tied to the Klamath for generations.

PROJECT FUNDERS AND PARTNERS

Project Funders

PacifiCorp

State of California

Project Partners

Trout Unlimited

American Rivers

Klamath Basin Coalition

Yurok Tribe

Karuk Tribe

Klamath Tribes

PacifiCorp

Klamath Water Users Association

The Nature Conservancy

Upper Klamath Water Users

Pacific Coast Federation of Fisherman

Salmon River Restoration Council

FISH AFFECTED

Species affected by this project.

Klamath Mountains Province Summer Steelhead

Oncorhynchus mykiss irideus
Klamath Mountains Province Winter Steelhead

Oncorhynchus mykiss irideus
Southern Oregon/Northern California Coast Chinook Salmon

Oncorhynchus tshawytscha
Southern Oregon/Northern California Coast Coho Salmon

Oncorhynchus kisutch
Upper Klamath-Trinity Rivers Fall-Run Chinook Salmon

Oncorhynchus tshawytscha
Upper Klamath-Trinity Rivers Spring-Run Chinook Salmon

Oncorhynchus tshawytscha

Outcomes

What this project has accomplished:

4

Dams removed

400+

Miles of spawning and rearing habitat reopened

13,310

Chinook salmon passed the former Iron Gate Dam site in fall 2025, just over a year after removal — nearly double the amount that passed immediately after dam removal

24

Years of CalTrout involvement, from early negotiations to dam removal

Project Resources

This study, published August 27, 2026 in Scientific Reports, part of the renowned Nature portfolio of journals, and led by CalTrout’s Damon Goodman, tracks how fast Chinook salmon have returned to the Klamath River after removal of the four dams (J.C. Boyle, Copco 1, Copco 2, Iron Gate), the world’s largest dam removal project. The team included the Karuk, Klamath, and Yurok Tribes, ODFW, CDFW, NOAA, USGS, Cal Poly Humboldt, and independent researchers.

Within just two migratory seasons, Chinook reoccupied 88% of their historical range, reclaiming 214 miles of river and tributaries. Returns nearly doubled year over year, from about 7,742 fish at the former Iron Gate site in fall 2024 to roughly 13,310 in fall 2025, with fish reaching Beatty Gap on the Sprague River, over 360 miles from the ocean, the farthest upstream record ever documented on the Klamath.

The findings offer early evidence that Klamath salmon, whose numbers had fallen more than 90%, are rebounding faster than expected now that the river runs free.

scientific REPORTs, nature

View the report here.

This report, “Steelhead Recovery After Large-Scale Dam Removal: A Biology-Driven Monitoring Framework for the Klamath River,” lays out the science plan for tracking steelhead recovery after the Klamath dam removals. Published June 23, 2026, by CalTrout, The Conservation Angler, tribal partners, state agencies, and universities, it doesn’t report final results, it sets the framework for answering how fast steelhead recolonize reopened habitat, what role resident rainbow trout play in rebuilding the population, and how genetic diversity shifts as connectivity is restored.

To answer those questions, the team combines genetics, juvenile and adult fish counts, and habitat assessments with angler-science integration, where trained anglers collect scale and tissue samples to extend monitoring reach. The report treats this as a long-term commitment, since recovery patterns will vary by tributary and may take years to fully understand.

In 2025, CalTrout and our partners released a report outlining findings from the 2024 sonar project. View the report below.

Steelhead Recovery After Large-Scale Dam Removal: A Biology-Driven Monitoring Framework for the Klamath River
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