Farm creates new river habitat for chinook salmon


Issue Date: May 10, 2017
By Christine Souza
Stationed on a barge and maneuvered by a tugboat, a crane hoists a salmon structure into the Sacramento River near Redding, as part of an effort by farmers, agencies and environmental groups to preserve salmon. The structure, called a “refugio,” is made of a large tree trunk and root wad that is bolted onto a limestone boulder. Once lowered into the water, these are designed to give young salmon a place to hide from predators.

Twenty-five salmon shelters called "refugios"—made of large tree trunks and root wads, bolted to 12,000-pound limestone boulders—have been lowered into the Sacramento River near Redding. A Northern California farm partnered with state and federal agencies in what's considered a first-of-its-kind project to benefit chinook salmon in the river.

"The overall goal is to improve the ecosystem," said Roger Cornwell, general manager at River Garden Farms, a diversified farm in Knights Landing that is leading the project. "This is our opportunity to get involved and to improve salmon numbers in the Sacramento River. A healthy ecosystem makes the whole river better for everybody."

The project won't directly help secure water supplies, Cornwell said, "but by having a healthy ecosystem, it definitely helps the regulators and water users work together."

River Garden Farms, state and federal agencies and others completed installation of the refugios in the river last week. The idea is to increase the likelihood young salmon will be able to grow in size and strength, to prepare for their journey to the Pacific Ocean.

The shelters are expected to serve as places for juvenile salmon to hide from larger predators and to take shelter from high-velocity water moving through the river. People overseeing the project said the shelters will entice the fish to remain in colder water longer, increasing their odds of healthy maturation.

"This is the first time that a deep-water habitat structure project has been done," Cornwell said.

He said the farm invested $400,000 of its own money and secured $200,000 from the U.S. Bureau of Reclamation.

"We are doing this because it is the right thing to do," Cornwell said. "Most of us in the farming community are solution-oriented. We've identified a problem and now we're here to fix it."

The concept of adding deep-water habitat structures to benefit salmon comes from two decades' worth of research conducted in the Sacramento River by scientist Dave Vogel, who is working on the project for River Garden Farms.

During the years while under contract with different municipalities, Vogel often mapped the riverbed around bridges that required retrofits or new construction. He said he consistently saw high numbers of juvenile salmon rearing behind the bridge piers.

"As the season progressed and winter-run eggs hatched out of the gravel, I would see literally hundreds of baby winter-run swimming behind the bridge piers. Unfortunately, those areas harbored lots of predatory fish," Vogel said.

After spending so much time researching the Sacramento River, and with access to the latest underwater camera technology, Vogel noted that the river is wide and deep, with not a lot of habitat complexity or structure on the riverbed, which makes it difficult for young salmon to find any cover from predators.

"Once it hatches from the eggs, that little salmon has to find its way 100 feet in either direction to the shoreline to find protection, and there's not a whole lot of habitat adjacent to the riverbanks," Vogel said. "We haven't had significant recruitment of large, woody debris, so now we have a situation where salmon do not have protection from predators or that high-velocity environment."

Vogel described the new effort as a pilot project that will require further evaluation to determine whether the young salmon are heavily utilizing the habitat structures.

"We have a variety of different structures, 25 structures that are now sitting along the riverbed in deep water of different-sized boulders. The idea is that over time we are going to come up with a variety of different habitats, in deep water, medium depths and shallow water," Vogel said.

The salmon restoration project represents one of at least 40 projects in the Sacramento Valley Recovery Program, a public-private partnership organized by the Northern California Water Association. The project is part of a continuing effort to help meet requirements of the Central Valley Project Improvement Act, which calls for restoring and replenishing spawning gravel and rearing habitat for salmonids.

"We are really interested in recovering the winter and spring runs, which are the endangered salmon runs in the Sacramento River system, so we have a series of projects that folks are working on, up and down the valley," NCWA President David Guy said. "Each project is designed to help a particular life stage for salmon, so it has to all tie together."

Guy said NCWA has worked to coordinate the various local projects.

"I think there is a general recognition that the best way to have secure water supplies is to have a healthy, dynamic aquatic ecosystem," he said. "The relationship between water supplies and fish and wildlife is just so intertwined that we have to be doing this."

California Farm Bureau Federation Associate Counsel Jack Rice said fisheries biologists and water agencies are learning more about how to improve fish habitat in ways "other than simply requiring more flows."

"During the past half century, California farmers have improved the economic efficiency of agricultural water use by producing twice as much with the same amount of water," Rice said. "We have a similar opportunity with habitat for fish. By using refugios along with other ideas and technologies to improve the ecological efficiency of environmental water use, we can improve conditions for natural resources in a way that also sustains agriculture."

(Christine Souza is an assistant editor of Ag Alert. She may be contacted at csouza@cfbf.com.)

Permission for use is granted, however, credit must be made to the California Farm Bureau Federation when reprinting this item.