Gov. Jerry Brown deserves credit for leading the fight against climate change in the face of Washington’s fact-free narratives. That’s why it’s so frustrating that his administration ignores scientific analyses regarding the impact of his controversial proposal to build two giant tunnels that would divert Sacramento River water under the Delta.

Despite years of assuring Californians that the new $17 billion tunnels would protect the San Francisco Bay estuary and would not increase the total volume of water exported from this ecosystem, the state’s own documents – including the Biological Assessment and Draft Environmental Impact Report/Supplemental Draft Environmental Impact Statement (RDEIR/SDEIS) – show the opposite.

Currently, less than half of the winter-spring runoff from the Central Valley reaches the Bay in an average year, and it receives even less during dry years. An overwhelming amount of research leaves no doubt that the San Francisco Bay estuary ­­– the largest estuary on the Pacific coast of the Americas – has been severely damaged by decades of this unsustainable water withdrawal. Unless we change course:

• Extinction of several native fish species is imminent;
• Fisheries for salmon and other species that support recreational businesses and thousands of commercial fishing jobs from Morro Bay through Oregon will collapse;
• Blooms of toxic cyanobacteria will become increasingly frequent;
• The estuary will continue to be dominated by invasive water-weeds and other non-native species.

The best available science consistently demonstrates that we must allow more of the water in Central Valley rivers to reach San Francisco Bay as part of any comprehensive response to this estuary’s decline. Even colleagues who offer tepid support for the tunnels concept acknowledge that “…the best option for smelt, and other native fishes, especially salmon, is … a large increase in freshwater flows through [their] habitat,” as scientists Peter Moyle and James Hobbs wrote in a Water Deeply op-ed last month.

Yet, contrary to suppositions made by Moyle and Hobbs, the governor’s tunnel project (misleadingly named “California WaterFix”) will increase water exports from the Delta (see, e.g., California WaterFix Biological Assessment Appendix 5A. Figure 5.A.A.3-20). Indeed, the state’s own analyses reveal that operations of the new water diversions will reduce the flow of fresh water to San Francisco Bay and accelerate the ongoing decline of Chinook salmon and other native species. Reductions in fresh water flow are expected to increase residence time and to decrease turbidity (cloudiness) of water in the Delta (see, e.g., RDEIR/SDEIS Chapter 4); such conditions promote the increasing frequency of toxic cyanobacteria blooms.

For years, cheerleaders for the tunnels have argued that “the status quo is unsustainable.” Indeed it is. Ironically, the state’s sales pitch for the expensive twin tunnels is now an exercise in rationalizing maintenance of the status quo and avoiding analyses that demonstrate that this project will make conditions worse. For example, rather than argue that this project will improve conditions for imperiled species, the state now only attempts to show that the project will not increase the risk of extinction, which is already high.

Yet, despite serious flaws and major gaps in the state’s analyses, they clearly show that the tunnels will harm native species. Survival of juvenile Chinook salmon through the Delta, already unacceptably low, is projected to decline under WaterFix. For example, California Department of Fish and Wildlife evaluated the expected effects of the tunnels on the endangered winter-run Chinook salmon and found: “Overall, the [Winter Run Life Cycle Model] results indicated lower abundances and lower cohort replacement rates under the Project compared to the [No Action Alternative]. Under all scenarios, abundance was lower under the Project relative to the NAA throughout the time series and all scenarios had a lower mean and median cohort replacement rate than the NAA.”

Other models of Chinook salmon survival indicated similarly poor results with operation of the proposed tunnels.

In addition, forage fish species, which are currently circling the drain, will continue to decline under the plan, increasing the likelihood that we will lose some of these populations forever. Even entrainment of fish into the existing south Delta export facilities – the one environmental problem the twin tunnels were designed to address – will increase dramatically for longfin smelt, a state-threatened species, as the Incidental Take Permit Application shows.

We live in a country where ignoring strong scientific evidence has become routine and extraordinarily expensive projects are promoted with the most cynical rhetoric. It’s disappointing to see this from a state that prides itself on environmental protection.

Reducing reliance on the Delta’s fresh water supplies is state law. California is also required to protect fisheries, water quality and endangered species. The twin tunnels project fails on all of these and other counts. Meanwhile, the Brown administration’s fixation with this risky, outdated and expensive engineering project diverts resources from practical solutions like water recycling and improved efficiency that can simultaneously improve water supply reliability and protect the estuarine ecosystem.

During the recent drought, Californians demonstrated that we can conserve a tremendous amount of water. But most water districts across the state have barely tapped the potential to improve regional self-reliance through water recycling, conjunctive use and stormwater capture. These approaches can secure the state’s water supply and protect fishing communities and the environment at far less cost than boring two giant tunnels under the Delta.

Californians deserve better. It’s time we followed the best available science to protect our imperiled ecosystems by investing in durable innovations that will secure California’s water supplies into the future.

The views expressed in this article belong to the author and do not necessarily reflect the editorial policy of Water Deeply.