By Christopher Weber | Associated Press

LOS ANGELES — California’s largest water agency on Tuesday approved a nearly $11 billion plan to help fund two enormous tunnels, breathing new life into Gov. Jerry Brown’s ambitious and controversial plan to remake the state’s water system.

The board of the Metropolitan Water District of Southern California voted to pay about $10.8 billion toward the twin-tunnel project supported by the governor.

“This is a historic decision that is good for California — our people, our farms and our natural environment,” Brown said in a statement praising the decision.

Brown wants California water agencies to pay to plan and build two, 35-mile-long (55-kilometer-long) tunnels to divert part of the state’s largest river, the Sacramento, to supply water to the San Francisco Bay Area, the agricultural San Joaquin Valley and Southern California. State water districts had previously balked at the $16 billion total cost of the two tunnels.

The MWD has been the steadiest long-term supporter of either one tunnel or two — saying each project would help secure water for its millions of urban customers.

While MWD staff recommended that the board choose the one-tunnel plan because it’s less risky financially, they have maintained that building the full Sacramento-San Joaquin delta project would provide more overall benefits to California’s water delivery system.

Tuesday’s vote pit MWD’s two biggest members, the city of Los Angeles and the San Diego County Water Authority, against its third-largest member, the Municipal Water District of Orange County — one of the agencies that pushed to get the two-tunnel proposal back on the agenda.

Los Angeles has the biggest vote under MWD’s system, which weighs the votes of member agencies according to assessed property values in their service areas.

Environmental groups have opposed the original twin-tunnel project, fearing Southern California water agencies would use the tunnels to drain too much water from the Sacramento River, above its delta with the San Joaquin River.

The Sacramento is the state’s biggest river and a vital supplier of fresh water to the San Francisco Bay, part of the largest estuary on the West Coast of the Americas.

Brown and other project supporters say the tunnel project would modernize California’s outdated north-south delivery system, where pumps and overall water withdrawals are blamed for the steady dwindling of native fish and other wildlife that depend on delta water.

Opponents rallied outside MWD headquarters to urge the board to reject both tunnel plans, which they fear will raise water bills and property taxes without delivering any water or economic benefits to Southern California residents.

The two-tunnel project would cost LA’s ratepayers an average of $1.73 per month in 2017 dollars, according to a report last year by Fred Pickel, director of the city’s Office of Public Accountability, who acts as a watchdog for the Los Angeles Department of Water and Power.