Kesterson National Wildlife Refuge in California’s Central Valley was an artificial wetland fed by agricultural runoff from irrigated farmland supplied by Sierra Nevada water through the California Aqueduct. As that water evaporated through aqueducts, canals, and fields, minerals concentrated, and drainage sent to Kesterson carried dangerous levels of selenium, pesticides, and other contaminants. By 1978, about 7,000 acre-feet of toxic water were reaching its evaporation ponds each year, and by 1983 deformities were reported in 60 percent of baby birds there. The resulting wildlife damage made Kesterson a national symbol of the ecological and political consequences of irrigation drainage in the western United States.