… Sam Cobb, wearing a long-sleeved shirt, bright-green cap and jeans, is hunched over the flood irrigation system at his farm in Blythe, California, near the Arizona border. … Cobb says some people call his method of watering crops archaic because it isn’t efficient at reaching the roots of crops, but it’s the best for growing dates that have roots everywhere. He has over 2,000 date palm trees on his farm, all of them originally born at his “home ranch” two hours away in Desert Hot Springs, California.  He spends his summers — a critical time for dates because that’s when they’re the thirstiest and the fruit ripens — “chasing water.”