California's Sacramento-San Joaquin Delta

The Delta at sunset. (Art Siegel/Flickr)
The Delta at sunset. (Art Siegel/Flickr)

If you live in California, chances are that the Sacramento-San Joaquin Delta matters to you. It’s the hub for California’s water supply. Two-thirds of Californians get their water from the vast inland Delta, which lies east of San Francisco Bay, at the confluence of California’s two largest rivers, the Sacramento and San Joaquin. The water reaches cities from Silicon Valley to San Diego, and supplies millions of acres of Central Valley farmland through sprawling infrastructure projects built over the past century.

But the Delta’s natural ecosystem has declined and it’s become ground zero for the state’s most contentious battles over water and endangered species.

The Problem

The Delta is home to a number of threatened or endangered species, including Delta smelt and Chinook salmon. Biologists point to a number of reasons for their decline. After the gold rush, farms replaced what was once a rich network of tidal wetlands. About 95 percent of the Delta’s historic habitat has been lost. Upstream dams have altered the rivers’ flow, and fish die when they’re drawn toward the large pumps that divert water to the Bay Area and Southern California.

The Latest

To protect fish species, limits were placed on how much water could be pumped out of the Delta. Now, Governor Jerry Brown is proposing a $24.5 billion fix, known as the Bay Delta Conservation Plan. Two 35-mile water tunnels would cross the Delta, bypassing the ecosystem from below. More than 100,000 acres of habitat would be restored. The majority of the costs would be covered by the water users.

Concerns remain about whether the plan would help the Delta’s ecosystem recover. Farmers and other residents in the Delta region fear permanent changes to their way of life. And water consumers south of the Delta are reluctant to pay for the project if it doesn’t include assurances that adequate volumes of water are delivered.