Gardening Without Irrigation

Without regular and heavy watering during high summer, dense stands of vegetables become stunted in a matter of days. Pump failure has brought my raised-bed garden close to that several times. Before my frantic efforts got the water flowing again, I could feel the stressed-out garden screaming like a hungry baby.
As I came to understand our climate, I began to wonder about complete food self-sufficiency. How did the early pioneers irrigate their vegetables? There probably aren't more than a...