STOCKTON (AP) — Signature gatherers paid by a wealthy Stockton-area farmer and food processor have started circulating an initiative to force large public works projects to go before voters for approval, and the measure is expected to qualify for the November 2016 ballot.

Dean Cortopassi’s ballot measure could threaten Gov. Jerry Brown’s $15 billion twin tunnel plan to send water around the Sacramento-San Joaquin Delta.

Cortopassi’s ballot initiative would require voter approval before the state could issue revenue bonds for any project costing more than $2 billion. That could make it harder to secure lucrative public works contracts and, in the case of the tunnels project, water deliveries.

Proponents of the Bay Delta Conservation Plan, which calls for building two underground tunnels 40 feet across and 30 miles long to send water from the Sacramento River around the Delta, are reacting with alarm. The water currently irrigates 3 million acres of farmland in the Central Valley and serves 25 million people as far south as San Diego.

“He has money,” said Robin Swanson, a consultant working with Californians for Water Security, which supports the tunnels project and holds a significant stake in the outcome of the ballot initiative. “And he has his own political agenda.”

Brown has said the project is needed to stabilize water deliveries relied upon by millions of Californians and to restore the Delta’s fragile ecosystem.

Cortopassi, who calls his measure the “No Blank Checks Initiative,” was a major donor to Republican Gov. Arnold Schwarzenegger before splitting with the Republican Party over Schwarzenegger’s advocacy for a Delta conveyance in 2008.

That year, he registered as an independent, bought full-page advertisements in The Sacramento Bee and The Record of Stockton criticizing the conveyance, and he ran ads on KCRA-TV in Sacramento.

Last year, Cortopassi once again bought space in major newspapers around the state, this time with a broader complaint about government spending. Beneath bold type reading, “Liar, liar,” Cortopassi accused Brown and lawmakers of “profligate spending” while failing to address long-term debt.

His advisers declined to make him available for comment. Tom Ross, a consultant working on the initiative, said Cortopassi is focused on controlling state debt, not on any specific public works proposal.

“It really is, ‘Hey, if we’re going to do major, major things in the state, and incur debt for the state, there ought to be a public discussion around it,” Ross said.