Filed Under: Environmental Issues | New York City | Water | Water

New York City ReserviorTHE ROLE OF FILTRATION Water filtration systems, whether installed at the tap or in a municipal facility, are designed to remove impurities that disinfection and settling do not remove. Depending on the type of filter, these impurities may include the cyst parasites giardia and cryptosporidium Of course, filtration technology is not immune to failure; even with filtration, preventative measures - what's called a "multiple barrier" approach - is the best method to safe, clean water. Since its creation in the 1800's, NYC's water supply has been unfiltered - but changes lie ahead. Croton Reservoir Future: The Croton system usually represents 10% of the City's supply, although during droughts its contribution can rise to 30%. Though the Croton water supply currently meets health standards, its future ability to meet new federal guidelines, without the addition of filtration, is questioned. Northern Westchester and Putnam County are experiencing intense development pressures in the watershed areas, introducing more septic systems and hard surfaces. The Croton reservoir system currently receives 6.5 million gallons of effluent daily from 68 wastewater treatment facilities. (By comparison, the Catskill-Delaware System, with a water capacity 10 times greater, receives less - 5.5 million gallons of effluent from 34 treatment plants.) The City has been under a federal consent order since 1992 to filter water from the Croton system. .The 1997 watershed protection agreement, as modified in May 2002, reaffirmed the federal order to build a filtration plant. The city is planning to build the plant under the Mosholu Golf Course, located in Van Cortlandt Park, in the Bronx. The plant is to be in operation by 2010 or 2011. The cost is expected to be around $1.5 billion. The city had considered three possible locations for the plant: in Van Cortlandt Park; on a waterfront section along the Harlem River; and on city-owned property in Eastview, Westchester County. The city expressed a clear preference for the Mosholu site. If a plant is built many environmental leaders are concerned that the costly project will reduce public pressure for watershed protection measures because they will be perceived as no longer necessary. Catskill/Delaware Filtration Waiver: The Catskill/Delaware supply currently meets the requirements of the federal Surface Water Treatment Rule. Since 1993, EPA has granted New York City several waivers from federal requirements to filter this water. The last, granted in November 2002 and due to be revisited in April 2007, is based on the City's commitment to take numerous steps to protect the watershed. Although the City has this waiver, it is still required to prepare for construction of a filtration plant for the Catskill/Delaware -at the same time it pursues the watershed protection programs outlined in the agreement (see 1997 Watershed Protection Agreement section). If the city is successful in maintaining the water's high quality, the EPA may waive the plant requirement entirely. Cost estimates for such a plant are upwards of $6 billion for construction alone.