Delta Conveyance Project
Zone 7 ratepayers are on the hook for roughly $350 million of a statewide tunnel currently estimated at $20 billion. The seismic case is real. So are the freshwater, ecological, and cost questions. This decision needs a serious public comparison before the next funding vote.
The Delta Conveyance Project is a proposed 45-mile, 36-foot-diameter tunnel beneath the Sacramento-San Joaquin Delta. Current statewide cost estimate: $20 billion and rising. Operational target: approximately 2040. Zone 7 is a participating agency, and Zone 7 ratepayers are on the hook for roughly $350 million of that cost.
This is the largest single reliability commitment in front of the board, and it belongs in the same comparison as groundwater banking, local storage, and the rest of the reliability portfolio.
The seismic case
USGS estimates a 72 percent chance of a magnitude 6.7 or greater Bay Area earthquake by 2043. Many Delta islands sit 25 feet below sea level on subsided peat soils. A major quake could breach levees, flood the Delta with saltwater, and cut off Zone 7's Delta-sourced water for months. Today, that water travels through a single pumping plant — the Harvey O. Banks Pumping Plant near Tracy. One quake, one plant, one supply. That is the case Zone 7 has made for the tunnel, and on the seismic math alone, it is a serious case.
The questions that still need answers
A tunnel does not create new water. It redirects existing Sacramento River flows before they reach the Delta, which shifts the freshwater balance downstream and carries consequences for farming communities, drinking water, and the estuary ecosystem. The Delta Counties Coalition has argued the project delivers only a 23 percent volume improvement to the State Water Project if operated as described in the Final EIR. Zone 7 is about to commit ratepayer dollars across a multi-decade timeline, and those questions should be on the same ledger as the seismic risk the tunnel is meant to solve.
What I will do on the board
- Do the homework before the next funding vote. Read the Final EIR, the project cost updates, and the opposition technical filings. Ask Zone 7 staff for a written explanation of how the seismic, cost, and environmental tradeoffs are being weighed against each other — on paper, in one document, ratepayers can read.
- Ask for an independent estimate of what Zone 7's roughly $350 million share would fund if it were redirected to local alternatives: groundwater banking expansion, PFAS-cleared well capacity, and stormwater capture. I want the numbers in front of the board before any further increase is approved.
- Push for a Zone 7 Delta resilience plan that works whether the tunnel is built or not. Either way, the Tri-Valley should not be one earthquake and one pumping plant away from running dry.