California's long-running water wars typically pit farmers against environmentalists, but this time the state's growers are facing off against each other about plans to build a massive water system in the Sacramento-San Joaquin River Delta.

Farmers like Steve Heringer, whose family has grown grapes and grains near the Northern California town of Clarksburg for five generations, said plans for a new canal or tunnel that would carry river water to farms and cities in the south could ruin his land.

But 150 miles south in the heart of the San Joaquin Valley, Steve Patricio said he can't see a future for his business of growing, packing and shipping cantaloupe and honeydew without a new tunnel or canal.

The issue of how much water should be pumped from the delta is vital to the two-thirds of Californians who rely on it for drinking water and the many farmers who depend on it to cultivate 4 million acres in the nation's most productive agricultural state. It's also crucial to the delta estuary, which experts say has serious environmental problems.

The decline of once-abundant fish species has triggered regulations that limited pumping in recent years. Roiled by the restrictions and a drought, farmers and urban water users south of the delta have rallied around plans for a new conveyance system, which they say would capture and divert river water around the delta to ensure an adequate supply.

"For anyone like myself, who lives and farms south of the delta, any solution without a new conveyance is not a solution. It's a step backwards," Patricio said.

But farmers in the delta view the Bay Delta Conservation Plan as a water grab. A similar sentiment killed a proposed canal at the ballot box in 1982.

Currently, various proposals are being prepared by state and federal agencies, environmental groups and water districts that contract for water from two existing government water projects.

Although officials haven't settled on a plan, some Northern California farmers think it's only a matter of time before a lot more water is pumped away from the area. They argue the planning process favors the water districts — or contractors — who pay for the planning and will benefit from a new water system.

"The plan is a joke. It's carried out by water contractors who want as much unrestricted water as they can get," said Mike Robinson, a fourth generation delta farmer from Stockton. "The decision of what to build has already been made; they are just falling over themselves to justify it."

Last month, the state Legislative Analyst's Office reported that a new agreement between government agencies and water contractors included provisions that could benefit the contractors and give them greater influence over the plan's content. According to the report, the state must get written authorization from the contractors to proceed with a public draft of the environmental review, and contractors can review work by consultants and could pull out funding anytime.

The water districts have spent $140 million so far on tasks such as preliminary engineering and design, environmental documentation and hundreds of meetings.

They have agreed to fund an additional $100 million.

After five Northern California representatives demanded the U.S. Interior Department withdraw from the agreement, officials announced they would seek public comment on the matter.

Officials are considering 10 alternatives for a new water system. One calls for doing nothing, but few seem to be talking about that option.

Officials have made the analysis of two alternatives public. A canal that would cut through properties east of the delta would cost $8.4 billion, while a tunnel would cost $12.7 billion.

Jerry Meral, the state Natural Resources Agency's deputy secretary in charge of the plan, said the proposals will be winnowed down to one option, which should be out in June. Construction could begin in 2017 and the new system could be operational by 2024.

Water users would finance the project through higher rates.

Delta farmers fear diverting water would further damage the estuary and increase salinity, making farming impossible. About 600,000 acres are cultivated in the delta, but farmers there said they already stopped growing some crops because of a rise in salinity, which they attribute to pumping that allows more ocean water to flow in.

"If they take the majority of the Sacramento River and divert it, it won't be coming through to flush out the salt," Robinson said.

State officials countered that computer modeling showed a new project wouldn't increase salinity in most of the delta.

Farmers also worry about changing the river's elevation, disrupting the system of pumps and siphons they rely on for irrigation and drainage.

But Meral said the goal would be to capture and store excess flows during high water years. The current proposal calls for pumping up to 15,000 cubic feet per second, but that much water only would be diverted for a few days every few years, Meral said.

South of the delta, the ability to pump more is "critical," said farmer Sarah Woolf.

"From a farming perspective, it's very difficult to invest in land or capital investments when you don't have reliable water deliveries," she said.

Woolf, whose family farms 1,000 acres of cotton, onions and tomatoes west of Fresno, said pumping restrictions meant her family couldn't plant on some of their land and had to lease land with better water access.

In recent years, farms in the area received about 65 percent on average of the contracted water. But the farms received only 10 percent of contracts in 2009.

"Most farmers plan for not getting enough water," Woolf said, "but there is a difference in getting less water and not getting any water at all."

Delta farmers counter that the state should improve the current system and create hundreds of smaller projects that recycle and store water.

Planning should take into account all farmland, said Barbara Barrigan-Parrilla, executive director of Restore the Delta, which represents delta farmers.

"You can't help one farming region by destroying another," she said.