Quote from another BYC member;
We have never grown barley for brewing purposes, but we did plant a field in it to graze lambs on during the winter of 2011. That year was the worst one-year dry spell on record in Texas, and we had a total of just shy of 7 inches of rain on our place that whole year. Our "normal" average annual rainfall is supposed to be around 19 or 20 inches. Barley is widely known as the most drought resistant of all the cereal grains commercially grown in the U.S., but in Arizona I think I would be more worried about the heat than the dryness. Winter grain crops usually have a tough time with hot weather. Either way your project sounds like a fun learning experience. Good luck!