Newsom Pushes Aggressive Timeline for Delta Tunnel, Sparks Clash Over Local Impact

As Governor Gavin Newsom intensifies his push to fast-track the Delta Conveyance Project, California’s ag sector is split on whether the $20.1 billion proposal is a water security solution—or a costly gamble with local consequences.

The Project in a Nutshell

The Delta tunnel, as proposed, would divert water from the Sacramento River through a 36-foot diameter, 45-mile-long underground tunnel, bypassing the current aging Delta infrastructure. It would send water directly to the State Water Project’s (SWP) south Delta pumps, which serve over 27 million Californians and 750,000 acres of farmland.

Supporters say the tunnel adds seismic resilience and climate-proofing. Opponents argue it’s a top-down project that will drain the Delta to benefit urban districts at the expense of rural and farming communities.

California’s Water Supply Is Shrinking

The science behind the push is sobering. According to the California Water Supply Strategy, the state is on track to lose 10% of its water supply by 2040—equivalent to 4 million acre-feet per year—due to warming temperatures, shrinking snowpack, and prolonged dry periods.

DWR also projects that SWP deliveries could decline by over 22% by 2070, a reduction of roughly 546,000 to 600,000 acre-feet annually—much of it ag water.

Is the Tunnel Worth the $20 Billion?

The tunnel is projected to deliver up to 909,000 acre-feet of additional water in wet years, providing more flexibility for the state to capture storm flows when they’re available. Over the project’s life, a DWR benefit-cost analysis pegs the value at $38 billion, or roughly $2.20 in benefits for every $1 invested.

Still, the real-world effectiveness is in question. As Steve Jackson, founder of Next Gen Water Consulting, points out:

“With Oroville full, we should be at 80% or more allocation this year—an additional 1.25 million acre-feet at least. The Delta regulations are what’s killing allocations. If we’re only getting 5% delivery out of a system built for 4.17 million acre-feet, will a $20 billion tunnel really change that?”

This is backed by DWR’s own numbers: despite full reservoirs in Northern California at the close of 2024, the initial 2025 SWP allocation was just 5%—214,589 acre-feet out of a maximum 4,172,786 acre-feet.

Farmland & Delta Concerns: Not Just Environmental

While environmentalists are focused on fish populations, growers in Delta counties are concerned about:

• 15+ years of disruptive construction

• Long-term redirection of water out of the Delta

• Reduced freshwater flows that damage soils and livelihoods

The region supports a $5.2 billion ag economy and over 500,000 residents. Many local water boards believe the tunnel will erode regional water autonomy in favor of centralized urban supply.

Alternatives with Ag in Mind

For the same $16–20 billion price tag, opponents suggest the state could:

• Expand recycled water use to reach 800,000 acre-feet per year by 2030 (state goal).

• Fund groundwater recharge and conveyance projects that store water locally rather than shipping it south.

• Add new or expanded reservoirs like San Luis, which could store an extra 130,000 acre-feet.

• Invest in modernizing levees and canals that are collapsing from land subsidence caused by groundwater overdraft.

  
  

Given that the San Joaquin aquifer has lost 60 million acre-feet since the 1960s—and SGMA now mandates sustainable use—investing in local groundwater storage isn’t just smart, it’s the law.

The Agriculture Angle: What’s at Stake?

Water Metric	Value
SWP average deliveries	2.56 million acre-feet/year
Farmland served by SWP	~750,000 acres
Climate-driven SWP loss by 2040s	~600,000acre-feet/year
Tunnel delivery in wet years	Up to 909,000 acre-feet
Groundwater lost since 1960s	~60 million acre-feet
Construction estimate for tunnel	$20.1 billion
Benefit projection	$38 billion (DWR economic analysis)

Sourced by: Berkeley Research Group & The State Water Project  

These numbers paint a clear picture: ag water supplies are becoming more volatile, and large-scale solutions are needed. But whether that solution is a tunnel or decentralized local infrastructure is still hotly debated.

Final Thoughts

Newsom’s tunnel project is making waves, but for California’s growers, the real issue is balance. Do we bet on one massive project with centralized control—or build diversified, localized systems that give ag producers more autonomy?

With every acre-foot hanging in the balance, it’s a debate worth having—loudly, transparently, and with growers at the table.