(FOX40.COM) — Construction and diving crews are installing a new underwater barrier along a section of the Sacramento River designed to prevent endangered fish from taking a wrong turn, but it is not a physical barricade.
On the Sacramento River near Walnut Grove, workers and divers on a construction barge are putting together a structure with lights that looks like a lighting grid that would hang over a rock concert.
The structure, once complete, will create bubbles, make loud noises and include flashing lights.
“(It is) high-density LED lighting that’s going to reflect into the bubbles,” Project Manager Shahid Anwar said to FOX40.com.
It is called a bio-acoustic fish fence and it is constructed underwater to create a sensory environment that repels fish.
The structure is being placed where the Sacramento River meets the Georgiana Slough.
Endangered chinook salmon on their way to the ocean sometimes take a wrong turn and go down the slough instead of continuing down the river.
“We’re hoping the project is going to be done by the end of October and is going to be operational by November 15,” Sadat, who is a senior engineer with DWR, said. “It’s going to help us make sure the salmon is not going to get into the Georgiana Slough.”
He adds that the bio-acoustic fish fences have proven effective in other places.
Studies have shown the chance of survival for the salmon drops dramatically if they end up in Georgiana Slough because, in this body of water, they are exposed to many dangers including other fish that like to feed on salmon.
Georgiana Slough leads to the interior Delta where the danger increases.
An earlier version of the bio-acoustic barrier was tested in Walnut Grove in 2011 and 2012.
Sadat said that the test reduced the number of fish going wayward into the slough by 67% in 2011 and 50% in 2012.
“That’s actually a massive number,” Sadat said.
Compared to a physical barrier, the bio-acoustic method does not impede water flows or boat traffic.
“We hired some consultants. They did a lot of navigational analysis and made sure it is not going to impact any kind of navigation,” Sadat added.
The project is paid for by the California Water Project, which balances the water needs of people and nature.
“This is basically saving the juvenile chinook salmon,” Sadat declared.
The barrier will operate underwater between November and May to coincide with the fall and spring runs of the chinook salmon.