Seventy-five years ago, on Dec. 11 1947, the 71-mile San Diego Aqueduct was dedicated and put into operation, bringing water from the Colorado River to San Diego. By 1949, 85 percent of all water consumed in San Diego was Colorado River water. Today, after conservation, desalination, and other efforts to add to local water supplies, some 70 percent of the region’s water supply still flows through the aqueduct system.