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Multitasking the Nation’s Rivers

The relentless buildup of heat-trapping gases in the air is tilting the global climate toward irreversible climate change. To help slow the pace, low-emissions hydroelectric power is booming around the globe.

In the United States, 7 percent of the total electricity supply is produced from fast-falling water released by dams hundreds of feet high along the nation’s rivers. In the Pacific Northwest, 60 percent of the region’s power comes from “hydro” alone.

Unlike the “new kids” on the sustainable-energy block — solar, wind, and waves — hydropower can claim over a century of carbon-neutral electricity production. Dams and reservoirs provide irrigation, drinking water, recreation, flood control, and other benefits. But over time, a more complex story has emerged.

For Many Fish Populations, an Upstream Battle to Survive

Each year millions of fish migrating between fresh and salt water to lay their eggs are chewed up in massive turbines, trapped below towering dams, stranded in weak water flows, or “cooked” in too-warm reservoirs. Meanwhile, predators feast on the easy prey.

Salmon, shad, herring, American eel, and other coastal river species are unable to journey past many of the 2,000 hydroelectric dams built long before the birth of modern environmental awareness. Unable to complete their life cycles, fish populations critical to our nation’s ecosystems, food supply, and fishing economy have dramatically declined — some to near extinction.

But, a string of federal laws in recent decades have given a voice to fish species entrusted to NOAA’s protective oversight.

Biologists, engineers, and attorneys from NOAA Fisheries’ Hydropower Program rely on this legal authority to negotiate with power companies and the Federal Energy Regulatory Commission when licenses to operate hydroelectric facilities come up for renewal and “trust species” are involved.

Other federal and state agencies, native tribes, fishing coalitions, and environmental organizations may also speak up for the fish. Negotiations over fish passage can take many years, and the final agreements remain in effect for up to half a century. The effort, however, is paying off.

Today, with the nation’s largest dams already built, power companies are investing the resources and the know-how to make their structures environmentally sound. State-of-the-art monuments of engineering prowess are improving fish migration in the West and elsewhere, sometimes with startling success.

Baker Lake: A Power-ful Case Study

Starting in 2000, NOAA Fisheries’ Northwest Region Hydropower Division worked closely with Puget Sound Energy (PSE) and other parties to analyze the salmon habitat and migration along Washington state’s Baker River, propose engineering solutions, negotiate a final settlement, and monitor effects.

This year, the innovative system, built by PSE to safely collect, monitor, and transport migrating fish around its Baker Lake Hydroelectric Project, boosted fish migration to a half million juvenile fish — up from 285,000 in 2008. That’s while continuing to produce 170 megawatts of power each year for surrounding counties. The award-winning system is already a model for fish-passage projects planned for Washington’s Lewis and Cowlitz rivers.

Elsewhere, fish ladders, screens, tunnel-like bypasses, and dam removals are helping to reverse the declining numbers of important migratory fish species. Since 2004, NOAA Fisheries’ Hydroelectric Program has opened up fish passage along nearly 1,000 miles of the nation’s rivers that have been blocked by hydroelectric dams and reservoirs.

Abundant fish or clean hydroelectric energy?

Thanks to innovative engineering and progressive legislation, our nation’s rivers can provide both.

Hydropower Dam


Sockeye salmon


Fish screens on either side of the swimming lane, or “raceway,” separate the fish heading downstream from the water entering the floating surface collector.


Floating surface collector as seen from Upper Baker Dam. The V-shaped float system marks the top of the shore-to-shore guide nets, which extend to the lake's bottom.