About 30 percent of Southern California’s water comes from Northern California via the State Water Project. But aging infrastructure 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 improve conditions for the Delta’s wildlife.
Millions of Californians, including 19 million in Southern California, depend on reliable water supplies.
About half the cost of large-scale local projects.
Provides habitat and protection for fish and wildlife.
Safeguards against vulnerabilities that threaten water reliability.
The Delta water system is outdated and unreliable.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, powerful existing state and federal pumps are strong enough to cause nearby rivers to flow in reverse. This can impact migrating and endangered fish, leading to declines in native fish populations.
A new tunnel pipeline is a safeguard against a major earthquake collapsing Delta levees, which could shut off water deliveries to millions of people, farms and businesses.
Nearly all of the water that is stored in Southern California for drought and emergency needs comes either from Northern California or the Colorado River.
Groundwater is Southern California’s single largest local water source. Groundwater managers rely heavily on high-quality water from the Delta to help replenish their basins.
A modernized system could capture enough water to refill reservoirs after big Sierra storms, providing flexibility and reducing conflicts with fish such as salmon.
Sierra snowmelt is pure enough to recycle again and again in Southern California, promoting more recycling projects in the region’s future.
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 Gray, Metropolitan Board Chairwoman
The Delta is the heart of California’s statewide water delivery system, representing the source of 30 percent of Southern California’s water supply. It's where the state's two largest rivers and their tributaries meet and mix with salt water from San Francisco Bay and the Pacific Ocean.
Modernizing the hub of the statewide water system is no small matter. But it is a matter of great benefit. Protecting water supply reliability from the state's single largest supply, the Sierra snowpack, and enhancing protections for the environment are far reaching investments that provide benefits for generations to come.
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 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 nearly 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.
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