The Californian Department of Water Resources hopes that underwater strobe lights and offensive electronic sounds contained within a curtain of bubbles will keep migrating salmon on the straight-and-narrow in the Delta.
The "bubble barrier" is intended to deter ocean-bound chinook salmon from leaving the main channel of the Sacramento River near Walnut Grove to take a risky detour into Georgiana Slough. Georgiana Slough leads young salmon through the predator-infested waters of the interior Delta toward huge state and federal water export pumps.
Studies indicate that 65 percent of the young salmon that enter Georgiana Slough don't survive. Many are eaten by striped bass or other predators, and some are lost to pumping operations of the State Water Project and Central Valley Project in the southern Delta.
DWR will begin installing the bubble curtain as early as this week at the head of Georgiana Slough. The barrier structure will be installed deep enough to allow at least 9 feet of clearance for boaters on average low tides.
The barrier will utilize Bio-Acoustic Fish Fence technology, combining acoustics and a strobe-lit sheet of bubbles to create an underwater wall of light and sound at frequencies that repel young salmon.