THE BURNED OVER DISTRICT

For most people the choice would be easy because there are many more places for almonds to grow than there are for salmon to spawn. But the current drought in California is set to cause great damage to almond growers in affected areas.

California’s almond orchards have been thriving over the past decade and now provide an $11 billion annual boost to the state economy. Covering 860,000 acres, they account for 80 percent of world production. But the growth coincides with another record development here — drought — and the extensive water needs of nut trees are posing a sharp challenge to state water policy.

Farmers in the area where almond production has been most consistent have relied on water from a federally controlled project that draws its supply largely from the Sacramento River. But that source is less reliable because of legal requirements that in a time of scarcity, waterways that nurture California salmon must also get available water flows.

Growers, some very wealthy, tried to get Congress to change those rules but failed. Also, new state groundwater legislation may eventually constrain farmers’ well drilling.

Almonds “have totally changed the game of water in California,” said Antonio Rossmann, a Berkeley lawyer specializing in water issues. “It’s hardened demand in the Central Valley.”

Farmers are planting almonds because, as permanent crops, they do not need to be replanted after every harvest. They have been steadily taking over from cotton and lettuce because they are more lucrative. “That’s the highest and best use of the land,” said Ryan Metzler, 45, who grows almonds near Fresno.

The problem is that not only do almonds and pistachios, another newly popular nut, need more water, but the farmers choosing permanent crops cannot fallow them in a dry year without losing years of investment.

Now the state is putting new controls on the groundwater that has gotten many farmers through the brutal drought — which still looms over the state, despite recent rains — and there is no certainty that the future of almond and pistachio orchards in areas like the western San Joaquin Valley is secure.

So almond growers are determined to be granted the water they need to keep their crops from dying, particularly in the Westlands Water District in the San Joaquin Valley, where 15 percent of the fields are covered with almond trees, up from 5 percent about 15 years ago. They chafe at the rise in the 1990s of environmental restrictions designed to help the survival of salmon species threatened by two generations of water diversions.

What they could get away with in wet times is no longer supportable in dry times. It will come down to who has the biggest clout, the fish or the nuts.