It would be the largest farm-to-city water transfer in US history.
And in a state that is both the nation's most populous and its most agriculturally productive, the controversial plan goes to the core of California's identity. The farm-rich Imperial Valley is being asked to share its imported water supplies with burgeoning San Diego suburbs. If it doesn't, the US Interior Department threatens to suspend the flow of surplus Colorado River water by year end.
The story echoes one of a century ago: a water transfer from the High Sierras to build Los Angeles - at the expense of majestic Owens Valley. But this time, the farming region just north of the Mexican border has no intention of giving up its economic lifeblood.
Watching in the wings are Utah, Wyoming, New Mexico, Colorado, Arizona, and Nevada. They've stood by for years while California has taken well over its allotment from the Colorado River, but they now need that water for their own burgeoning populations.
"After well over a century of doing things one way to favor the production of food, this new agreement represents a huge social and cultural shift," says Richard Golb, former president of the Northern California Water Association, and now a consultant in Portland, Ore. "It's not just a water transfer. It's a shift of resources, wealth and values from the desert to the coast."
With a Dec. 31 deadline, four of southern California's largest water districts are meeting in coming days to discuss whether to sign a 75-year water deal. The proposal would help cut the state's water usage - which has long been well over its fair share - by shifting water currently used by farmers to urban customers in and around San Diego.