Something fishy going on in the turbine

Scientists at the Pacific Northwest National Laboratory have developed a sensor-packed synthetic salmon designed to swim through the turbines at Bonneville Dam and other hydroelectric projects in the Columbia River.

The six-inch, rubber-coated sensor fish will measure the conditions that real fish encounter as they pass through turbines of hydroelectric dams on the way to the ocean, and all the data gathered will go toward the design of fish-friendly turbines.

As the sensor fish pass through the turbines, their sensors are said to gather specific information such as changes in pressure and acceleration. Little balloons attached to the fish inflate and bring them to the surface at the end of their journey and an attached micro-radio transmitter helps to locate and recover the data-collecting devices in the dam tailrace, downstream of the turbine exit. The sensor fish then are attached to a computer and the recorded data is downloaded for analysis.

‘This technology will provide scientists with the first opportunity to measure actual environmental conditions in operating hydropower turbines—at measurement scales directly applicable to juvenile fish,’ said Tom Carlson, leader of Pacific Northwest’s ecology group.

A school of nine sensor fish went through turbines at Bonneville Dam near Portland approximately 90 times in December 1999 and January 2000.

The study was designed to compare the passage conditions of two turbines—one installed when the dam was built in the 1930s and one equipped with a minimum gap runner, a new turbine runner design that is expected to make turbines more efficient and less harmful to fish.

Another field study in June collected data on the conditions present in high-flow outfalls or bypass systems designed to pass fish around the dams rather than through the turbines and that study will continue in October.