In 1980, as California was recovering from its longest drought since the Depression, state lawmakers thought they had found a solution to weather future water shortages.
A 43-mile canal would route fresh Sierra runoff around the Sacramento-San Joaquin Delta, an environmentally sensitive region that sits at the heart of California's water-delivery system. But the plan proved too controversial and was trounced two years later in a statewide election.
A quarter century later, the idea is back in play.
Declining fish populations, fragile levees that could crumble and allow sea water to contaminate the Delta and rising oceans caused by global climate change have prompted policy makers to reconsider the Peripheral Canal.
They say a new plumbing system could solve the Delta's worsening environmental problems and safeguard California's water supply.
"There is a growing recognition that the present layout of the levees and delivering fresh water out of the Delta is something we can't maintain long term," said Robert Twiss, a University of California, Berkeley, environmental planning professor who advises the state on water issues.
Efforts to protect a threatened fish, the Delta smelt, have created a sense of urgency and refocused the debate on building a canal that would route California's freshwater around the Delta and its many trouble spots.
Earlier this spring, state and federal courts ruled separately that pumping operations are killing the fish. After a record low count of the smelt's population, the state Department of Water Resources temporarily shut down its main pumping plant for more than a week, forcing some cities and rural water districts to cut back on water use.
The largest estuary on the West Coast, the Delta is home to 500,000 people and includes 300,000 acres of agriculture and 750 plant and animal species.
For a half century, it has served as the hub of the State Water Project, channeling Sierra snowmelt from the San Joaquin and Sacramento rivers through a network of 19th century earthen levees. The water is diverted into a reservoir in the Central Valley between Stockton and the eastern San Francisco Bay area. From there, it is pumped into the California Aqueduct and delivered to about 25 million people in Southern California and the Bay area. That water also irrigates 750,000 acres of farmland throughout the state.
But the pumps that send the water from the Delta to the aqueduct are so powerful they actually reverse the Delta's flow. They also suck in smelt, chinook salmon and other fish, a situation that conservation groups say has decimated the Delta's fish population and has led to numerous lawsuits.
Experimental changes to the pumping schedule have not prevented a steep decline in the Delta smelt or eliminated invasive species.
In their rulings this spring, the state and federal judges sided with sportfishing and environmental groups. They said neither the U.S. Bureau of Reclamation nor the state Department of Water Resources has the proper environmental regulations in place to protect fish.
Collective efforts such as the ongoing California and Federal Bay-Delta Program, which is in disarray despite having spent more than $3 billion, have failed to reach a consensus about how to proceed with the Delta.
Halting the pumping to save fish populations is just one argument for building a canal to send water around the Delta. Relying on the fragile estuary to hold the water supply for two-thirds of the state is risky in myriad ways.
An earthquake or Sierra flood waters could destroy large sections of the aging levee system, allowing fresh water to flood vast tracts of farm land or subdivisions. Moreover, global climate change is expected to increase sea levels and send more salty water from San Francisco Bay into the Delta.
Initially proposed in the 1960s, the Peripheral Canal was conceived to deliver better water and more of it to Southern California, as well as protecting the Delta's fish populations.
The concept was to tap into the Sacramento River below the state capital and pipe the water more than 40 miles directly into the reservoir that feeds the pumps, called the Clifton Court Forebay. That way, the fresh water supplies would bypass the Delta entirely, safeguarding them from natural disasters or rising seas.
Since its defeat in 1982, mention of the Peripheral Canal has been taboo in hallways of the state Capitol. That in part is due to the north-south divide it caused.
Renewed talk of a canal already has opened old wounds.
During a community meeting in Stockton last month, Delta residents and farmers packed into an elementary school classroom to warn of another water grab by the south.
Rather than help restore the Delta's ecology, critics fear a canal would give the state an excuse to abandon the Delta. Instead, they want the state to invest in levees, pump less water south and manage the region for fishing, boating and other recreational activities.
"We don't see anyone jumping up to write off Los Angeles or San Francisco because of sea level rise," said Barbara Barrigan-Parrilla, executive director of the grassroots group Restore the Delta. "We certainly don't stop building there because of seismic threats."
Meanwhile, farmers worry a canal would siphon fresh water out of the Delta, leaving them with unusable, salty water that dries out soil and crops.
John Herrick, an attorney with the South Delta Water Agency, said piping water around the Delta would put 500,000 acres of the state's most fertile farmland out of production.
Environmental groups, which were split in the 1982 election, also are skeptical a canal would solve the state's water problems. Of chief concern is whether too much water would be routed past the Delta, leaving the rivers and the estuary without enough fresh water to preserve their sensitive habitats.
"What people aren't talking about is what are the environmental pitfalls and problems that arise if you do this?" said Tom Graff, California director of Environmental Defense.
Also unanswered is where a canal would be built, how big it would be, who would pay for it and what kind of safeguards would be installed to satisfy Delta communities. Nevertheless, lawmakers say there is a new willingness and openness on both sides to explore a canal or some other system. Some lawmakers and Schwarzenegger say the Delta cannot meet the state's water demands while also protecting fish.