One of the worst environmental disasters in California was at Kesterson Reservoir, a disposal site for agricultural drain water which also doubled as a wildlife refuge. Initially, animals and plants thrived in the artificial wetlands that were created here, but in 1983, it was found that birds had suffered severe deformities and deaths due to steadily increasing levels of chemicals and toxins, especially selenium. In the next few years, almost all the fish species died and algae blooms proliferated in the foul water. These have not only been bad on San Joaquin River ecology, but also caused pollution to the sources of most of the large aqueducts in the state including the California and Delta-Mendota Canals.