FIVE POINTS  (AP) — As a giant harvesting machine uprooted and sucked in hundreds of tomato plants a row at a time, Dan Errotabere contemplated massive strips of bare land on his farm.

“Everything we have in our operation is under duress,” he said, looking at a stretch of fallow acres once covered in garlic, onions and other crops.

Errotabere and hundreds of others who run massive farms in California’s Central Valley have left tens of thousands of acres barren this year after seeing their water supplies severely curtailed. He and the other members of the nation’s largest federal irrigation district say the restrictions are hindering their growth and jeopardizing their future.

As a result, the powerful Westlands Water District, which comprises 700 large-scale operations spanning 600,000 acres in western Fresno and Kings counties, has become one of the loudest proponents and top financiers of a twin tunnel project that would provide a new avenue for shipping water from the Sacramento-San Joaquin Delta south to farms and cities.

Westlands has fought for years to get more resources from the delta for the farms it represents, making its presence known in the state’s water wars with numerous lawsuits against environmental regulations that have cut into their supplies.

District famers see the intervention as critical for their survival, particularly the latest push for the tunnel system. While other agricultural and urban water districts in California have also faced reductions, Westlands’ members see their situation as more precarious, because their district has junior water rights and faces the sharpest cuts when supplies are tight.

“Dry years in farming, you learn to live with it,” Errotabere said. “But it’s hard to invest into operations, equipment and labor if you don’t have a reliable water supply.”

Without the tunnels, farmers say, more of the fruits and vegetables in grocery stores across the nation will come from foreign countries where food safety regulations aren’t as strict as U.S. requirements.

Critics, including environmental groups that oppose the project, say the tunnels might not restore Westlands’ dwindling water supplies, yet could further harm the fragile delta ecosystem and cost taxpayers billions of dollars.

Some say parts of the district should be allowed to permanently die off because Westlands farmers have relied for far too long on cheap federal water to overplant thousands of acres of water-intensive trees on salty land with substandard groundwater.

“These guys are at the end of the line, and they’re always trying to put themselves at the front at the expense of other water users and the fish,” said Tom Stokley, a water policy analyst with the nonprofit California Water Impact Network.

Once dominated by cotton growers, today Westlands — which includes Harris Farms, one of California’s biggest operations, and Tanimura & Antle, the nation’s top lettuce grower — grows nearly 60 different crops, from fruits and vegetables to nuts, with a total value of $1.6 billion.

Westlands members have seen water deliveries cut by 40, 60 and even 90 percent in recent years as the delta ecosystem’s deterioration triggered Endangered Species Act regulations to protect fish and limit delta pumping. Other water districts saw mostly smaller reductions.

The districts poured millions of dollars into a planning process for a new conveyance project. Last July, Gov. Jerry Brown announced his support for the project they came up with: a 35-mile long twin tunnel system coupled with a massive habitat restoration effort.

Critics say the project’s costs are too steep— for water users and for taxpayers. Water districts would put up $16.8 billion for tunnel construction and mitigation. Another $8 billion for restoring over 100,000 acres of floodplains and tidal marsh would come from state and federal funds and water bonds, with little certainty of how the project would affect fish.

“This is a very expensive project that will impose billions of dollars of costs ... and it’s not sufficient to meet the fish recovery standards; some of the species could be worse off,” said Kate Poole, an attorney with the Natural Resources Defense Council.

Poole said federal contractors such as Westlands are already behind in paying back the costs of existing irrigation facilities. On top of construction costs, state projections show that tunnel water would be extremely expensive for users: at least double the current price of water.

And how much water Westlands would see is uncertain. State officials say that if fish species don’t recover or don’t recover quickly enough, less water would be pumped through the tunnels. Climate change could further restrict pumping.

Most likely, the tunnels would deliver the same amount of water as existing facilities do today, said Mark Cowin, director of the state’s Department of Water Resources. In dry years, when fish are most stressed, the tunnels would actually deliver less water, he said. In wet years more could be delivered, and excess would be stored if there’s space in the reservoirs, he added.

Without the tunnels and the habitat restoration efforts, Cowin said, California’s water situation will get much worse.

“If we don’t take action, we expect that fish species will further decline, there will be even tighter restrictions on water pumping, and we’ll see much lower annual water deliveries than today,” Cowin said.

Westlands officials, who have not yet approved funding for tunnel construction, say the thought of further cutbacks scares them the most. “The alternative of not taking action ... would be extraordinarily high,” said Jason Peltier, the district’s chief deputy general manager.

For Errotabere, a third generation farmer who has invested in water-saving drip irrigation, more cutbacks would mean hiring fewer workers, buying less equipment and contributing less to the local tax base.

“It’s kind of like if you had a building and had only 20 percent of your power,” Errotabere said, referring to his water deliveries being slashed to 20 percent this year. “We’re a food basket, we grow everything, and we’re going to be sitting idle.”