This post from Pruned looks at a proposal to turn a contaminated reservoir into a "bioremediating ecological machine".
"An Associated Press article published by The New York Times a couple of months ago told us that the Elysian and Silver Lake, 'two reservoirs that supply drinking water' to sections of Los Angeles, were found to contain 'high levels of the carcinogen bromate.' When alerted, the city's Department of Water and Power took them both out of service and announced that beginning early this year, they would drain, clean and refill the reservoirs, a process that could last until the summer."
"Alternatively, they could consider implementing in parts or in whole a design proposal from out of the Department of Landscape Architecture at the California Polytechnic State University in Pomona."
"This proposal - the product of a collaboration in 2005 between Ken McCown, Andy Wilcox and Kevin Hinders, with research and production assistance provided by students - the fenced-off Silver Lake is turned into a public open space hosting once giant bioremediating ecological machine, one that could theoretical render inert the cancer-causing bromate and other pollutants."