The nation’s largest and most technologically advanced seawater desalination plant celebrated its first anniversary Wednesday in the North County. In its first year of operations, the Claude “Bud” Lewis Carlsbad Desalination Plant produced enough high-quality water from the Pacific Ocean to meet approximately 10 percent of the region’s demand, according to officials. The plant has relieved pressure on imported water supplies, reduced state mandates for emergency conservation measures and helped the region pass the state’s stringent water supply stress test.