About a third of Southern California’s water comes from Northern California via the State Water Project, passing through the Sacramento-San Joaquin River Delta. But aging infrastructure, climate change and the declining health of the Delta ecosystem threaten the reliable delivery of water supplies to Southern California. Modernizing the Delta conveyance system will strengthen the state’s water transportation infrastructure and provide greater operational flexibility to improve aquatic conditions in the Delta.
At the direction of Gov. Gavin Newsom, California has initiated an environmental review process for the construction of a large tunnel that would carry water from the north underneath the Delta to delivery infrastructure in the south, bypassing the Delta’s imperiled environment. This single-tunnel conveyance project would feature two intakes with a total diversion capacity of 6,000 cubic feet-per-second (alternatives also will be evaluated). As Metropolitan continues to increase local supplies and promote conservation in Southern California, investment in the state’s water delivery system is the most affordable, cost-effective way to secure the region’s water future.
Learn MoreThe Delta water system is outdated and unreliable. The system relies on levees that are vulnerable to earthquakes, floods and rising sea levels under climate change. And when these levees fail, water rushes into the lower-than-sea level islands behind them, pulling in salt water from the bay and diminishing water quality before it can be delivered to Southern California, the Bay Area and Central Valley farmland. In addition to protecting this water supply from threats posed by climate change and earthquakes, the modernized system resulting from the Delta Conveyance Project would provide greater operational flexibility to meet multiple regulatory requirements intended to protect sensitive fish species that reside in or migrate through the Delta.
With more severe droughts and precipitation increasingly falling as rain instead of snow, the project can capture enough water during big storms to store for drier times. It would also guard against increased salinity from sea-level rise.
A new tunnel pipeline safeguards against a major earthquake that could collapse aging Delta levees and shut off water deliveries to millions of people, farms and businesses.
A modernized system will provide greater operational flexibility to improve aquatic conditions in the Delta.
As California’s largest water source, past investments have made this water supply an affordable option.
High-quality northern Sierra water provides a necessary foundation for local supply projects, including recycling programs and replenishment of groundwater basins.
Water projects require vision, leadership, and thoughtful and deliberate decisions, because they take a long time. We have to be visionaries and advance that vision together... because together we are so much stronger than we are apart.
- Gloria D. Gray, Metropolitan Board Chairwoman
The Delta is the heart of California’s statewide water delivery system. It’s where the state’s two largest rivers and their tributaries meet and mix with salt water from the San Francisco Bay and the Pacific Ocean. Gov. Newsom has prioritized Delta conveyance as part of the state’s Water Resilience Portfolio, a plan to ensure California has a reliable water supply for future generations in the face of climate change and other challenges. As Metropolitan diversifies our water supply by reducing future reliance on the Delta and investing in local supplies, the Delta Conveyance Project is one of many steps we must take to ensure the region’s water resiliency.
Water is the lifeblood of our state, sustaining communities, wildlife and our economy. For more than a year, my Administration has worked to assemble a blueprint to secure this vital and limited resource into the future in a way that builds climate resilience for all communities and sustains native fish and the habitat they need to thrive.
- Gov. Gavin Newsom on the California Water Resilience Portfolio
Metropolitan’s mission to ensure a reliable, high-quality water supply for Southern California is the guiding principle for its support and investment in a conveyance project in the Delta. Its decisions, along with those of many other local, state and federal agencies, are essential to the project’s ability to move forward.
View Milestone DecisionsThe Delta Conveyance Design and Construction Authority was formed in May 2018 to help design, develop and implement the proposed Delta Conveyance program, an infrastructure project to support the resiliency of California’s fresh water supply via a proposed single tunnel solution.
The materials below are designed to educate and inform Southern Californians on the Delta conveyance project.
The mission of the Metropolitan Water District of Southern California is to provide its service area with adequate and reliable supplies of high-quality water to meet present and future needs in an environmentally and economically responsible way.
The Metropolitan Water District of Southern California is a state-established cooperative of 26 member agencies – cities and public water agencies – that serve 19 million people in six counties. Metropolitan imports water from the Colorado River and Northern California to supplement local supplies and helps its members develop increased water conservation, recycling, storage and other resource management programs.
© 2018 The Metropolitan Water District of Southern California. All rights reserved. Some photos featured on this website are courtesy of DWR.
