Delta Flows: Delta Residents and the Single Tunnel Plan

In a recent column for CALmatters, Ellen Hanak and Jeffrey Mount of the Public Policy Institute of California offer a bit of advice to us Delta residents.“By proposing to build one tunnel instead of two, Gov. Newsom has opened the door for a grand compromise. The Delta’s many interests should seize this opportunity.”

Thanks for the tip, PPIC. Residents of the San Francisco Bay-Delta (there are more than 4 million of us) agree to evaluate proposals by the Newsom administration with clear eyes and in a spirit of collaboration. Here are some questions Delta people plan to ask as we engage with this new process.

Does the plan reduce water exports?

The primary purpose of a single Delta tunnel is no different than the purpose of twin tunnels: to facilitate water transfers from Northern CA to Southern CA. A large single tunnel can do as much damage, if not event more, than two tunnels. 

While we understand the need to share water with the southern half of the state, it must be at sustainable levels. For ten years, we and our coalition partners have been asking for a water availability analysis. How can we possibly know how much water we can transfer from a collapsing estuary and its upstream water sources if we don’t know how much water is available, and how much has already been promised in water deliveries?  No full analysis has been done on how a Delta tunnel will draw down on water flows from the Trinity, the Feather, and McCloud River basins, in addition to the Sacramento River basin, among others. We think it is important to ask what will be the impacts on wild and scenic protection of these rivers in addition to Sacramento Valley groundwater basins? These questions are never raised by PPIC as it advocates for water transfers as the solution for solving San Joaquin Valley groundwater and agricultural water needs.

Does the plan protect Northern California Indian Tribes?

The continued overdraw of Northern California water sources will further impact salmon restoration. Salmon are essential to the cultural and economic well-being of Northern California Indian tribes. These tribes are part of California’s water environmental justice community. Yet, zero to little acknowledgement of this water EJ community ever shows up in PPIC’s water analysis.

Does the plan protect Bay-Delta Environmental Justice Communities?

As with Northern California’s Indian Tribes, PPIC never acknowledges that Delta environmental justice communities exist, let alone what the impacts will be from greater water transfers on all the Delta region’s residents.

PPIC held a conference in February championing solutions for some water environmental justice communities in CA, but not all. At that conference, the message became clear that increased Delta water exports were the solution for San Joaquin Valley water needs. It is disheartening that California’s think-tank on public policy continues to divide California’s water EJ Community. 

Percentage-wise, the Delta region has the largest environmental justice community in California, with parts of Stockton hitting the 95 percentile, and small Delta towns compromised of 52% non-English speaking residents.

In small north Delta farm communities, farmworker families will lose their homes, jobs, and groundwater supplies with Delta tunnel construction, while Stockton’s significantly large environmental justice population will see significantly increased pollution and salinity in its Delta and groundwater supplies resulting from tunnel operations, in addition to the proliferation of toxic algal blooms throughout its waterways.

Will the plan seriously consider climate change?

PPIC continues to focus on the need to capture more water during wet periods from the Delta as the solution for the San Joaquin Valley’s water woes as part of climate change planning. We agree. Opportunities exist to share more water during wet periods, while ensuring that enough freshwater flows from the Delta to the San Francisco Bay. There are also opportunities to capture more rainwater in each region of California.

However, the primary proponent of the Delta tunnel, the Metropolitan Water District of Southern California, continues to model water exports in board meeting presentations as increasing during dry periods, exactly when the Delta needs freshwater flows to prevent toxic algal blooms, and to keep salinity out of the freshwater areas of the estuary. 

What does climate change modeling tell us about water availability for exports during extended periods of drought? PPIC remains vague on that issue, even though a reduced Delta watershed will result in a smaller volume of water for delivery to Southern California. Yet, tunnel bond repayments will remain constant in the lean water years.

Will our levees be fixed?

Whether a tunnel for new conveyance is built, or the existing pumps are re-engineered instead, Delta levees will still need to be strengthened to protect human life, and the billions of dollars of public utility infrastructure within the Delta. If an earthquake event were to occur, the Delta would experience 100% of the loss of human life — and 80 percent of the state’s economic loss. In addition, engineering reports completed thus far on the twin tunnels by WaterFix engineers are woefully incomplete as the tunnels have not been designed for seismic safety. After an earthquake it would be much harder to fix an underground tunnel, than levees. These are all factors ignored by PPIC water analysts.

With regard to sea level rise, mitigation will need to begin with wetlands restoration in the San Francisco Bay and Suisun Marsh, extending into the Delta. But it should be noted, the existing Delta pumps are inland, off river, and protected by levees which can be heightened and strengthened. The proposed intakes for any tunnel are on the open Sacramento River, not protected, and end up underwater with sea level rise on the Sacramento River. 

Looking Ahead

We “Delta interests” look forward to participating in the new process with an open mind. But a single Delta tunnel as described presently by PPIC is not the silver bullet for restoring the Delta and ensuring water supply reliability for our neighbors to the south.  We are happy to evaluate the Newsom administration’s new plan, when it is written.

Barbara Barrigan-Parrilla ( is director of Restore the Delta.

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