In 1985 Kesterson Reservoir was issued an abatement order to close by the California State Resources Control Board due to the 1983 discovery of a 64% rate of deformity and death of embryos and hatchlings of wild aquatic birds. According to the USGS, the high deformity and death rates were a result of selenium contamination traced through irrigation drainage and sourced to the bedrock of the California Coast Ranges. The USGS defined the biogeochemical pathway of selenium moving "from rock to duck” as the 'Kesterson effect". The group of symptoms and effects observed in birds from research at Kesterson Reservoir is known as "Kesterson Syndrome".