Central Valley almond trees reflected in flooded irrigation water. To many people -- particularly environmentalists and family-farm aficionados -- the Westlands Water District, on the dusty west side of California's San Joaquin Valley, conjures up an image of a sprawling empire of large-scale agribusiness. Roughly 600 farmers own land within the district, and grow a veritable cornucopia of tomatoes, almonds, pistachios, lettuce, cantaloupes, grapes, and other crops. Many farms here are huge, to be sure: One family farms at least 25,000 acres. But there are plenty of smaller farmers like 42-year-old Shawn Coburn, who grows 1,200 acres of mostly almonds. …