The plan to build a canal or a tunnel to move water around the Delta instead of through it is nothing new. The roots of the idea go back to the 1970s. Though long sought by water interests, the project remains as controversial as ever.
Trans-Delta System, Peripheral Canal, Bay Delta Conservation Plan, California Water Fix, and now, the Delta Conveyance Project – the idea of a canal to route water around the Delta is certainly not new. It was initially thought of as part of the master plan for the State Water Project but wasn’t included in the initial construction due to cost considerations. In the 1980s, plans were begun to construct such a canal, but it was put to a statewide vote, which was soundly defeated due to concerns about its potential impact on the Delta’s ecosystem and native fish populations.
Despite past setbacks and strong opposition, the idea of constructing a bypass around the Delta was never entirely abandoned. Over the years, it has continued to be a topic of intermittent discussion, with geography playing a significant role in the level of opposition. The most vocal opponents are often found in the northern part of the state, particularly within the Delta itself.
For a complete history of the Delta Conveyance Project and its predecessors, click here.
The most recent version of this concept is the Delta Conveyance Project. This project involves the construction of two new 3,000 cubic feet per second (cfs) intake facilities in the north Delta. These facilities would divert water to a 45-mile tunnel, which would run largely parallel to Interstate 5 before turning west towards Bethany Reservoir, where it would connect with the California Aqueduct. If completed, this tunnel would be one of the longest water tunnels in the world and the state’s second-largest infrastructure project, following the high-speed rail.
Advocates of the Delta Conveyance Project argue that it is a necessary step to enhance the state’s water supplies, which are crucial for the economy. They assert that the new infrastructure, equipped with cutting-edge technology, will rejuvenate the Delta’s ailing ecosystem and benefit native species by facilitating more natural flow patterns. However, opponents counter that the project’s cost is prohibitive and that it could disrupt the estuary’s necessary freshwater flows, potentially hastening the collapse of the Delta’s ecosystem and native fish populations.
Fixing the Delta – a vexing problem
The Delta is many things to many people: a magnificent estuary, fertile and productive agricultural lands, a popular recreation spot – it is also the hub of the state’s water system and the center of the water debate for decades. Despite many failed attempts to address the Delta’s issues, today the Delta is undeniably in a state of crisis, as evidenced by plummeting populations of several of the Delta’s threatened and endangered fish species, some to new historic lows. Debate rages on about the causes: is it water exports, altered flows, loss of habitat, contaminants, harmful non-native species, or something else? Add to that, some question whether the Delta’s levees can withstand earthquakes or strong storms, and the rising sea levels and other climate change impacts only add to the disputes. (For a pictorial look at this complicated place, check out this slideshow.)
Many (but not all) of the Delta’s current problems can be attributed to the southern location of the facilities that draw in water for the state and federal projects.
But when the project pumps are in operation, they actually create ‘reverse flows’ that pull the water southward towards the pumps, rather than allowing it to flow out towards the San Francisco Bay. These reverse flows adversely affect salmon migration patterns and impact many fish species by pulling them towards the intake facilities where they can be subject to predation or entrainment in the pumps. In an attempt to reduce the impacts on fisheries, in recent years, regulators have limited the amount of water the state and federal projects can export from the Delta.
The facilities planned for the Delta Conveyance Project are intended to alleviate this problem; by diverting water from the north Delta, a more natural direction of river flows would be reinstated, and fish would be protected by state-of-the-art fish screens.
However, it is the diversion of water from the north Delta that is one of the main points of controversy (although there are others): Delta advocates say that diverting the water before it can flow through the Delta will only deprive the estuary of needed freshwater flows, worsen water quality for farmers and residents, and drive native species to extinction. Project proponents counter that the new state-of-the-art facilities will improve environmental conditions and be more protective of fish, and new operating criteria will protect spring outflow and Sacramento River flows. Delta stakeholders are wary that protective criteria will be overridden if it means less water can be exported. The science and the modeling are uncertain, and so the debate rages on.
New intakes in the north add flexibility to operations, better for fish
The Delta Conveyance Project is a key component of Gov. Gavin Newsom’s Water Supply Strategy, which predicts that the state may lose as much as 10 percent of its water supply by 2040.
Traditionally, California’s water infrastructure relied on winter snowpack in the mountains, which acted as a natural reservoir, slowly releasing water into downstream reservoirs and the Delta. However, climate change has shifted precipitation patterns, leading to more rain and less snow in winter, increasing flows into reservoirs and the Delta. This creates a storage challenge for water managers, as reservoirs must also maintain space for flood protection, limiting their capacity to store surplus water from intense winter rainstorms for future use.
Having the north Delta intakes, with state-of-the-art fish screens and operational criteria designed to be protective of fish populations, would provide the ability to divert water during winter high flow conditions while adhering to environmental standards. DWR asserts this enhanced winter diversion capability is necessary for capturing the increased winter flows expected due to climate change.
The Department of Water Resources (DWR) estimates that if the project were operational in 2024, it would have captured 941,000 acre-feet of water, sufficient to supply over 9.8 million people for a year. Storms can offer valuable water capture opportunities even during drought years, such as 2021-22, an extremely dry year. If the project had been completed by then, it could have captured an additional 236,000 acre-feet of water, effectively doubling the meager 5% water allocation for that year and mitigating severe water restrictions imposed in Southern California.
Paying for the project: Costs and benefits
The project is estimated to cost around $20 billion, which would be paid for by those who receive the water – primarily ratepayers in Southern California but also the Bay Area and some agricultural districts in the San Joaquin Valley. Engineering innovations could potentially reduce costs by $1 billion.
But is it worth the cost?
The Department of Water Resources (DWR) released a benefit-cost analysis for the Delta Conveyance Project in May of 2024. The analysis, released in May 2024, was prepared by Dr. David Sunding, Emeritus Professor at UC Berkeley. He found that the project would create billions of dollars in benefits for California communities, including reliable water supplies, climate change adaptation, earthquake preparedness, and improved water quality, and that for every $1 spent, $2.20 in benefits would be generated.
In response, Restore the Delta circulated a report prepared by the Dr. Jeff Michael, Director of Public Policy Programs at the University of the Pacific, who critiqued the benefit-cost analysis as flawed and inflated. Dr. Michael said the analysis relies on questionable assumptions, such as ‘extreme’ projections of urban water demand growth, and omits significant environmental costs, particularly on salmon and other endangered species. He also noted due to the high cost of water and minimal benefits, agricultural users are not likely to participate, shifting more of the costs onto Metropolitan Water District’s ratepayers.
As a rebuttal, Dr. Sunding wrote a memo addressing Dr. Michael’s criticisms, saying they reveal some significant misunderstandings about the role of the benefit-cost analysis, the treatment of risk, and other important aspects. In his memo, Dr. Sunding specifically addressed each of Dr. Michael’s points, and defended his analysis as based on industry standards, follows industry best practices, and is informed by current, applicable and documented data and policies.
Project Timeline
The Department of Water Resources certified the final Environmental Impact Reporton December 21, 2023. The project is currently working through numerous permitting processes, including endangered species requirements, a water rights hearing at the State Water Board, and consistency with the Delta Stewardship Council’s Delta Plan.
The current schedule anticipates the permitting to be completed by the end of 2026, with construction beginning in 2029. The project will be operational by the end of 2044 or the beginning of 2045.
More information on the permitting process and schedule is available here: https://www.deltaconveyanceproject.com/planning-processes
For more information on the project
The Delta Conveyance Project, official website of the project
- Environmental Impact Statement (finalized December 2023)
- Links to fact sheets, FAQs, and videos
- Benefit Cost Analysis
- Cost Estimate
- Facts About the Economic Value of the Delta Conveyance Project
- FAQ: Understanding Costs, Benefits, Funding and Financing for the Delta Conveyance Project
- Response to Dr. Jeff Michael’s Critique of the Benefit-Cost Analysis for the Delta Conveyance Project
- Delta Conveyance Project operations plan
Supporters of the project
The project is supported by the water contractors who would receive water from the project, and from business interests. Among the supporters:
- State Water Contractors: This coalition of State Water Project contractors supports the project because it is expected to improve water reliability and supply.
- Californians for Water Security: This coalition says the project is essential for ensuring a stable and reliable water supply, modernizing infrastructure, and supporting economic and environmental objectives in California.
- Metropolitan Water District: Metropolitan supports the project because it is integral to securing a more reliable and efficient water supply for Southern California, addressing infrastructure vulnerabilities, and supporting long-term water management goals.
- Southern California Water Coalition: The Southern California Water Coalition supports the project because it is expected to improve water reliability, address infrastructure challenges, and support both economic and environmental objectives.
Opposition to the project
The Delta Conveyance Project has faced significant, long-standing opposition from various groups and stakeholders for several reasons:
- Environmental Concerns: Critics argue that the Delta Conveyance Project could significantly disrupt habitat for salmon and other native fish, and that the environmental impact report does not adequately address the long-term effects on fish populations and lack sufficient mitigation measures.
- Construction Impacts: Construction could disrupt ecosystems and threaten habitats, lead to increased sedimentation and pollution in the Delta’s waterways, disrupt farming operations, affect local water supplies, and increase traffic and noise in surrounding areas.
- Water Quality: Critics argue that changing the flow patterns could lead to increased salinity and degrade the water quality for agricultural and drinking water purposes.
- Alternative Solutions: Some critics believe there are more sustainable and less disruptive alternatives to the Delta Conveyance Project, such as improving water conservation, enhancing groundwater recharge, or investing in new technologies for water efficiency.
Among the groups in opposition:
- Restore the Delta: Restore the Delta is dedicated to public education, policy development, and community empowerment to protect the Sacramento-San Joaquin Bay Delta, emphasizing environmental justice and sustainable local economies.
- Sierra Club: The mission of Sierra Club California is to promote the preservation, restoration, and enjoyment of California’s environment, and enable chapters and grassroots activists to speak as one voice to promote California conservation.
- Friends of the River: Friends of the River protects and restores California rivers by influencing public policy and inspiring citizen action.
- California Water Impact Network: The mission of C-WIN is to protect and restore California’s water resources, particularly in ways that benefit local communities and ecosystems.
- Food and Water Watch: Food & Water Watch fights for sustainable food, clean water, and a livable climate for all of us.
For the latest news on the Delta Conveyance Project posted on Maven’s Notebook …
