SAN FRANCISCO -- Water has flowed from Northern California's snow-capped peaks to the south's parched cities ever since the California Aqueduct was built in the 1960s. Now, amid one of the worst droughts in history, state officials are considering an audacious plan to send some of the water back uphill.

State water engineers say using pumps to reverse the flow of the aqueduct would be a first in a drought. It would also be a complex engineering challenge, requiring millions of dollars to defy gravity.


"There is no place on planet Earth where an aqueduct is designed to go backwards," said Geoff Shaw, an engineer with the state Department of Water Resources who is reviewing the proposal. "But they have a need for water in a place where they can't fulfill it, and this is their plan to fix it."




Long celebrated as an engineering marvel, the California Aqueduct is a 420-mile system of open canals and massive pipelines that serves millions of Californians, including those in the state's biggest population centers: the San Francisco Bay Area, Los Angeles and San Diego.

Under the plan, water districts would be allowed to pump into the aqueduct the emergency supplies of water they store in underground reservoirs in Kern County, about two hours north of Los Angeles. That banked water and other extra supplies would raise the level of water within a small, closed section of the aqueduct.

Then, pumps powered by diesel engines would push the water over locks and back upstream, against the southward pull of gravity. Farmers upstream could then pump the water out to their fields.





"Our crops need some amount of water just to keep alive," said Dale Melville, manager-engineer of the Fresno-based Dudley Ridge Water District, one of the agencies proposing the project.

The flow has been reversed only once before -- in 1983, when heavy rains forced state officials to operate emergency pumps to send floodwaters northward, Shaw said.


"This is a year where you really have to look at every single possible way to move water around to where it's needed," said Joan Maher, operations manager for the Santa Clara Valley Water District.



If it doesn't rain much next winter, the districts might seek to continue pumping the water backward in years to come, Melville said.

"Ideally we would hope it's a one-time thing," he said, "but it would be worthwhile to have this as an insurance policy."