So, they could stop beef and chicken production without crashing the local economy or depriving the market of meat, freeing up scarce water to sustain almond production?
Look, according to Slate, almonds use 1.1 trillion gallons of water per year in CA.
http://www.slate.com/articles/technology/future_tense/2014/0...
There are 5,000,000ish head of cattle in CA. This thing:
http://www.uaex.edu/publications/pdf/fsa-3021.pdf
suggests that the most water that any cow needs per day is 20 gallons. 20 x 365 x 5million = 36.5 billion gallons of water per year. Let's assume that that's holy shit an order of magnitude low, and it's 365 billion gallons of water per year -- so it's still only 1/3rd the amount of water that almonds use.
And thus, we talk about the amount of water that almonds use.
California's reservoirs don't care about gaming numbers about "gallons per calorie", they care about how many gallons are used where.
And the simple fact is that almond production uses many, many, many, many more gallons of California water than cattle production does.