FRIANT, Calif (AP) - Gov. Arnold Schwarzenegger has signed a far-reaching water bond intended to rebuild California's crumbling water system and fund new dams to save up the precious resource for dry years.

Yet at a time when several Western states are preparing to tear down dams rather than build new ones, the governor acknowledged Monday that he will face hurdles in persuading voters to support the $11 billion measure in November. The proposal was approved by the Legislature last week and signed by the governor on Monday.

In recent months, officials in Oregon, Washington and California have agreed to spend millions to dismantle colossal dams built decades ago in order to protect native fish species, following legal tussles over water between the federal government, environmentalists, Indian tribes and farmers.

In the San Joaquin Valley, where most of the nation's fruits and vegetables are grown, farmers warn their crops will wither if the government doesn't build a second reservoir above Friant Dam, which was built in the 1940s to nurture croplands below.

"For decades, Californians have been fighting about water," Schwarzenegger said. "I've heard the pleas of the people here from this valley, I have heard the pleas of the people of the state of California, and I think the legislators have heard those pleas as well. So I am here to tell all of you help is on the way."

The bond bill is one of five bills passed last week in Sacramento, but it will not become law unless voters approve it on next November's ballot. Aside from new money to upgrade aging canals and pumps, the landmark package includes funds to restore the ecologically fragile Sacramento-San Joaquin Delta, promote water conservation and monitor groundwater.

Environmentalists and some fiscal conservatives have raised concerns about the milestone water deal, which also sets aside $3 billion that can be used to increase California's water supply by building new dams and underground storage.

Among the leading candidates likely to compete for those taxpayer funds is Temperance Flat, which would be built in the narrow canyon above Friant Dam on the San Joaquin River, northeast of Fresno. It could hold up to 1.3 million acre feet of water, which local officials and farmers say is crucial to satisfy agriculture and a growing population.

A three-year drought, coupled with environmental restrictions on the amount of water that can be pumped south from the delta, have given new urgency to the debate as farmers have had to idle hundreds of thousands of acres of croplands and lay off tens of thousands of farmworkers. Cities, too, have been forced to ration water supplies, and demand will only grow as California's population is projected to soar to 60 million by 2050.

"This is one of the most fertile areas of God's green earth and it's going to stay that way because Democrats and Republicans crossed the aisle and made it happen," said comedian Paul Rodriguez, an ally of the governor's who plans to stump for the water bond on late-night talk shows in coming months. "It's going to be difficult to tax yourselves, but this is what we're asking you to do."

Still, a U.S. Bureau of Reclamation recently found that the proposal to build a second dam there barely meets the federal government's criteria for projects to be deemed cost effective.

The existing dam has spawned problems. Last month, the government began an ambitious plan to restore the dry river channel beneath it, releasing water flows aimed at reawakening the state's second-largest river so salmon can flourish there once again.

"It's somewhat ironic that they're signing the bill and celebrating the possibility for more dams at a place that has been such a problem for fish species," said Jim Metropulos, a senior advocate with the Sierra Club, which opposed the water bond.

State Sen. Jeff Denham, a Republican whose district lies in the San Joaquin River's floodplain, said he opposed the bill because it didn't assure there would be enough water to irrigate his constituents' fields, since the bond doesn't guarantee funding for specific dams.

"We've got to build new reservoirs now or else we're going to see our No. 1 industry go out of business and there will be crisis in the Central Valley," Denham said. "We have taken a historic stance and moved the water debate further along. It's just not good enough yet to sell to the voters of this state."