The McNary Dam spans the Columbia River, stretching between Washington and Oregon. (Andrea Starr / Pacific Northwest National Laboratory Photo)
Some 71 percent of the world’s renewable energy comes from hydropower and more dams are being built all of the time. But while energy wrung from rivers doesn’t release greenhouse gases and contribute to global warming, there are still environmental costs.
And in the Northwest, the main concern is the harm caused to salmon traveling up river to spawn and downriver as juveniles returning to the ocean. The dams injure and kill fish in a variety of ways as they navigate fish ladders and bypasses, plunge through turbines and swim through unnaturally warm reservoirs.
Initial Sensor Fish prototype. (Photo via PNNL)
Scientists at the Pacific Northwest National Laboratory (PNNL) in the Eastern Washington city of Richland hope to make that journey less life-threatening with new technology to measure the physical impacts of hydropower infrastructure on fish and through improvements to tools that track salmon migration.
The Department of Energy’s PNNL has invented something called the Sensor Fish, a device that’s about 3 1/2 inches long, or roughly the size of juvenile salmon called a smolt. The sensor is dropped into the water at the top of a dam and travels through it, collecting information on pressure, acceleration, rotational velocity and orientation. The next-generation device takes about 2,000 measurements per second and is retrieved below the dam.
The reusable sensors will be available beginning this spring for about $3,500 a piece. They’re being manufactured by Minnesota-based Advanced Telemetry Systems (ATS).
“There is nothing else like this out there,” said ATS sales manager Joe Allen. “This is a first.”
PNNL also created the first and possibly only injectable tracking device that can be inserted into young salmon to monitor their migration for up to three months. The minute acoustic transmitter is roughly twice the size of a grain of basmati rice. These are also licensed for manufacture by ATS and cost $250. They’re used only once.
The hope is that data from the two devices can help dam engineers and operators design and manage hydropower plants in a more fish friendly manner.
“We want to identify what kind of dam operations are affecting fish behavior,” said Daniel Deng, a laboratory fellow at PNNL who helped lead the research. Using the two technologies together, “we can correlate the fish behavior with the physical conditions.”
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