Last week, state authorities rejected a controversial proposal to chemically treat New York City’s Croton reservoir–a plan that had environmentalists and upstate legislators on the warpath. Now, it looks like the city’s options have run short: It must either wade through a time-consuming, expensive Environmental Impact Statement or build a multi-million dollar filtration plant to keep the city’s water clean.
Up to 30 percent of New York City’s drinking water comes from this Westchester County reservoir. But the reservoir periodically fails to meet color and odor standards. In addition, the federal government is now working out stricter health standards to which the Croton probably won’t measure up. So the city is now under a court order to build a $600 to $700 million water filtration plant, a project that has been bitterly opposed by Bronx and Westchester residents.
In order to avoid building this plant, the city’s Department of Environmental Protection has been asking the state for permission to dump about 30,000 tons a day of a coagulating chemical called alum into the reservoir. The alum (aluminum sulfate) would clean the water by combining with the organic materials that foul it, creating a sludge that settles at the bottom–about 40 million gallons of it each year.
Environmental experts and Westchester County officials slammed the pilot project, calling it a potentially dangerous experiment. Although the city Department of Environmental Protection has periodically used this chemical to clean reservoirs, it has been used only intermittently and on a much smaller scale. State officials say the Croton project would be one of the largest involving continuous alum use in the country.
According to biologists, large doses of alum may also kill beneficial microorganisms and fish. “The DEP is using a New York State resource as a laboratory,” complained Brendan Kennedy, a lawyer with the Hudson Riverkeeper, an environmental watchdog group.
On November 29 the Westchester County Board of Legislators chimed in, voting unanimously against the city’s proposal. “We heard that adding alum to the reservoir could change its color and kill it,” said Michael Kaplowitz, the board’s environmental committee chair. “We felt that there was potential for harm to the public.” The Riverkeeper also threatened to sue.
Now, the state has joined their side. In a December 23 letter, state environmental authorities concluded that the alum project is risky enough to warrant a full EIS, which requires extensive studies of the potential effects on the environment, as well as public hearings.
This decision may scuttle the city’s alum plans for good. At a public hearing earlier this year, DEP’s drinking water quality control director Michael Principe said that preparing a full Environmental Impact Statement would simply take too much time to make the pilot project worthwhile.
But environmental activists welcomed the state’s decision. “The environmental community has long been in favor of a full EIS for the alum project because this is using one of New York City’s most important reservoirs on an experimental basis,” said Marian Rose, president of the Croton Watershed Clean Water Coalition.