The House today approved an ambitious California water bill that favors farmers, splits the state and pressures the Senate.

In a highly partisan vote, the Republican-controlled House approved the legislation which would lengthen irrigation contracts, override state law and boost deliveries to farms south of the Sacramento-San Joaquin Delta. Most dramatically, the bill replaces one San Joaquin River restoration plan with something far less ambitious.

"Flushing water into San Francisco Bay is not helping to recover species, and people are suffering needlessly," said bill author Rep. Devin Nunes, R-Visalia, adding later that his bill "gives (water) reliability, not only to farms but to the environment."

Approved by a 246-175 margin, the bill marked one of the few times the full House has confronted California's water woes. The nearly five-hour debate, though, also underscored how the bill has magnified regional and personal differences.

"This is a power grab," said Rep. John Garamendi, D-Walnut Grove. "It's a water grab, and it's an imposition of the federal government over the state."

The bill faces an uncertain future. Democratic Sens. Dianne Feinstein and Barbara Boxer both oppose the legislation, as does the Brown administration in Sacramento, and the Obama administration has threatened a presidential veto.

"Senator Boxer and I will do everything we can to make sure it won't pass," Feinstein said, "and I don't believe it will pass."

At the same time, Feinstein said she would "look at it and see" if individual provisions might merit separate consideration. Rep. Jim Costa of Fresno, one of only 10 House Democrats to vote for the bill, stressed that Feinstein's participation will be essential for anything to happen.

Joined by Rep. Jeff Denham, R-Turlock, and House Majority Whip Kevin McCarthy, R-Bakersfield, Nunes introduced the Sacramento-San Joaquin Valley Water Reliability Act last year in response to repeated severe cutbacks in irrigation water deliveries south of the Delta.

The legislation returns federal irrigation contracts to 40 years, rather than the 25-year limit imposed in 1992. It eases water transfers and preempts strict state laws that might impose stricter environmental standards.

Though the water is California's, the controversy crosses borders. In a rare floor speech, House Speaker John Boehner praised the legislation; a sign it could have political legs. From the other side, suggesting broader resistance, Colorado, Wyoming and Oregon state officials warned about the dangers of preempting state laws.

"This direct weakening of the deference to state water law is unacceptable," Wyoming State Engineer Patrick Tyrrell wrote. "It poses a threat to water rights and water administration across the Western United States."

In hopes of reassuring Western officials, lawmakers included extraordinary language declaring the federal preemption of state laws in California would not be a precedent elsewhere. Skeptics doubt this language can make the precedent simply disappear.

Following extensive negotiations, from which House Democrats say they were excluded, GOP lawmakers further included language intended to assure Sacramento Valley residents that they won't lose water to San Joaquin Valley farms.

"This bill places senior water right holders in a safe and secure position," said Rep. Tom McClintock, R-Elk Grove, the chair of the House water and power subcommittee.

But Rep. Mike Thompson, D-St. Helena retorted that crafting the bill "in the proverbial backroom" made any GOP assurances shaky.

In what Nunes calls the "lynchpin" of the legislation, the bill blocks a 2009 law intended to help restore water flows and Chinook salmon to the San Joaquin River below Friant Dam. The bill calls for about 100,000 acre-feet of water to flow below the dam annually, less than half of what the current law demands; the result would be hospitable for some fish species, but not salmon.

Scaling back the river restoration could reduce federal spending by at least $190 million, according to the Congressional Budget Office.

"This is our priority in the House," Denham said of the overall bill. "The Senate may not agree with us, but we'll never know unless we have the debate."

Rep. Grace Napolitano of Santa Fe Springs, the senior Democrat on the House water and power panel, led other Democrats in unsuccessful efforts to amend the bill. Some, like a failed Napolitano amendment to end water subsidies, seemed designed to strike a symbolic chord.

Some 200 farm, water and business organizations have endorsed the bill, ranging from the Westlands Water District to the U.S. Chamber of Commerce. Other water districts and some cities are more leery, particularly about the San Joaquin River provision.

All of the cities, counties and farm bureaus fully endorsing the bill come from south of the Delta. No city or county north of the Delta endorsed the bill, though some Sacramento Valley water districts did.

"It frustrates me to see the division on the House floor that has politicized the issue," Costa said.