Myths and Facts

There’s a better path forward.

Rather than relying on costly and disruptive infrastructure like the Delta Tunnel, communities and experts across California are advancing innovative, sustainable solutions that protect water, ecosystems, and people. Explore the alternatives that put the Delta first.

  • FACT: Same project. No better than before and is not a compromise.

    The Delta Tunnel project is just a smaller version of previous tunnel proposals that would deprive the Delta of badly needed freshwater inflows from the Sacramento River. Even with one tunnel instead of two, it could create permanent drought conditions in the Delta by taking a range of flows from the Sacramento River to export fresh water supplies at the expense of water quality for Delta area residents.

  • FACT: Levee improvements are the best earthquake safeguard.

    No earthquake, including the earthquakes of 1906, 1989, 2014 has damaged Delta levees. In fact, seismic risk to current conveyance systems is much greater in the southern San Joaquin Valley and Southern California regions where major fault lines cross poorly maintained water delivery systems. Water export agencies have the resources to withstand supply interruption of six months from a major earthquake in the Delta, should one occur. Maintaining and improving levees are the best ways to protect critical water supply infrastructure from earthquake risks and climate change.

  • FACT: Would not secure future water supplies as the climate changes.

    Governor Newsom’s August 2022 Water Supply Strategy - Adapting to a Hotter, Drier Future states that California’s water supply may shrink by 10%. However, the Delta Tunnel Draft EIR analysis unreasonably assumes the hydrologic future will be similar to the last 100 years.

  • FACT: The state hasn’t promised improved conditions for fish.

    Improving conditions for the Delta’s imperiled fisheries is not one of state’s objectives for the current Delta Tunnel project. Instead, the state seeks “operational flexibility.” A prior version of the Tunnel (the Bay Delta Conservation Plan) did aim to improve the Delta ecosystem, but the fish agencies did not find that the project improved conditions for fish, so that project was eliminated.

  • FACT: State estimates Delta exports to increase by 25%.

    According to the Draft EIR, Delta exports with the Tunnel are estimated to increase by 25%, average Sacramento River flows near Hood would decrease by up to 7%, and Delta outflow would be reduced by 4%.

  • FACT: Financial incentives cannot repair tunnel impacts to the Delta.

    The state has developed the concept of a Community Benefits Program in recent years. However, this program would not address any environmental impacts of the project. No amount of funds or “leave behind” infrastructure could restore the damage done to the Delta if the Tunnel was built and operated.

  • FACT: Results in a multitude of significant negative impacts.

    Building and operating the Delta Tunnel would negatively impact Delta communities, permanently scarring Delta landscapes and waterways. The project would harm family farms, agricultural operations and historic legacy and Delta communities, including the following impacts:

    • 3,787+ converted acres of prime, unique farmland along with more saline water and reduced crops.

    • 70+ significant impacts requiring mitigation.

    • 17+ significant impacts on Delta communities identified, including noise, air quality, aesthetics, and agriculture.

    • $20+ billion cost to statewide ratepayers.

    • 13+ years of disruptive construction across 6 counties with 4,383,500+ truck trips on Delta roads.

    Massive water intake structures on top of productive farms and adjacent to Delta legacy communities.

  • FACT: Can’t deliver water that doesn’t exist.

    The draft EIR reports the tunnel would only provide 13-15% of the state’s water supplies from the Delta. How can a $16 billion tunnel that’s only used for 13-15% of supplies provide reliability? It can’t.

    Additionally, the state continues to ignore the fact that, in an era of ongoing drought conditions, there will be no water to reliably deliver. The tunnel would not provide one additional drop of water to the system. It only provides the biggest straw.

  • FACT: Tunnel would still negatively impact vulnerable communities.

    Though the state has met with underserved communities and tribes, that engagement has not led to meaningful consideration of the available alternatives to the Tunnel or changes to the project that avoid the most major negative impacts. These project impacts are environmentally unjust and will burden communities in and around the Delta.

  • FACT: Would divert water throughout the year.

    The bypass requirements for the North Delta Diversions could allow diversions of up to 6,000 cubic feet per second (cfs), with 5,000- 7,000 cfs bypass flows left in the Sacramento River. These new diversions have the potential to create drought-like conditions all year long in the Delta and are not limited to big storm events.

    Additionally, the state claims that if a Delta Tunnel had been operational during the big storms in October and December of 2021, about 236,000 acre-feet of water could have been captured. This claim is not supported with a detailed explanation as to how it would be possible to capture this much water while following existing regulatory and other constraints.

  • FACT: Generates conditions that harm fish.

    Some argue that moving some of the exports to the North Delta would reduce reverse flows in the South Delta that draw fish to those export pumps. However, reverse flows would still occur in the South Delta if the Tunnel was built because those facilities would continue to be used for up to 87% of the State’s water exports from the Delta. When the new Tunnel would be used, it would cause reverse flows in a new location – the Sacramento River.

DWR Tunnel Impacts on the California Delta

This map outlines more than just a construction plan. It traces a path through one of California’s most vibrant and vital regions: the Sacramento-San Joaquin Delta.

The Delta is a place of extraordinary natural beauty and deep cultural roots. Home to 4 million residents, it supports multi-generational farming communities, Tribal nations, and small towns shaped by winding waterways, fertile fields, and rich traditions. It’s also a living ecosystem, where salmon migrate, birds pause along the Pacific Flyway, and locals fish, farm, and gather.

But this way of life is at risk. The proposed Delta Tunnel project would carve a path through the region, bypassing the Delta to divert water from the Sacramento River and send it south to the Bethany Reservoir, removing water from the heart of Sacramento and away from the communities that depend on it.

The red and orange lines on the map show where the tunnel would cut through the region, bringing years of large-scale construction to the heart of Delta communities. These rural towns face increased traffic, noise, and dust disruptions that could reshape daily life for families, farmers, and small businesses.

This map tells a clear story: the project would place enormous strain on the land and the communities that make the Delta special. Protecting the Delta means protecting not just its fragile environment but also the people and cultures that call it home.