Stream-bed gravel restoration, predator control and the strategic placement of rocks and trees are just a few projects that the San Francisco Public Utilities Commission believes can be tackled along the lower Tuolumne River to aid the area's native fish, rather than the increased flows that the State Water Resources Control Board has proposed. On Tuesday, the Turlock Irrigation District Board of Trustees voted unanimously to endorse San Francisco's plan.
"San Francisco has been a great partner to us, and they share our vision of a restored Tuolumne River that our science says can happen with much less water than the state board's proposal," said TID Director Michael Frantz.
San Francisco's alternative plan comes in response to the state's call for 40 percent increased flows to provide habitats for fish and wildlife upstream of the Delta, and was developed using scientific studies funded by SFPUC, TID and the Modesto Irrigation District.
The $34 million plan provides other ways to ensure the salmon and steelhead trout in the Tuolumne River are able to thrive, such as pressure-washing and restoring the gravel along the river's bed where salmon lay their eggs, reducing the number of predatory bass in the river by hosting fishing derbies and relaxing catch limits, improving fish habitats along the river by placing large rocks and felled trees in central locations, controlling parasitic river plants and constructing a $12 million structure, called a weir, that would block non-native predators from advancing along the river.
"The weir is one of the most vital components of the plan because our science has shown predation to be such a huge problem for the Tuolumne River," said Frantz.
Non-native predators are a major contributor to juvenile mortality for Chinook salmon, and according to studies, there is a persistent and large population of non-native predators, including black bass and striped bass, in the Tuolumne River. The latter accounts for approximately 15 percent of loss due to predation on the river.
The five-foot tall weir would be placed in the river near Hughson, and would contain openings for the area's native fish and small boats to slip through.
"It's a comprehensive package, but certainly the most important aspect is the predation suppression," said Frantz.
San Francisco's alternative plan would be paid for over the course of the project's life by the three water providers (SFPUC, TID and MID), said Frantz. The plan has the support of local growers, who under the state's proposal would suffer great loss, and after SWRCB looks over the alternative they will consider it for adoption, along with their own proposal later this year.
Despite the wet months that the Central Valley has experienced recently, the surplus of water in the Tuolumne River will not affect either proposed plan.
"I think that we all recognize that water is a precious resource in California, and having one wet year doesn't mean we have license to be wasteful of water going forward," said Frantz.