Big Water Projects in the Big Apple

New York City gets drinking water from three watersheds and from an aquifer in Queens. Water from the Catskill and Delaware watersheds is unfiltered, thanks to upstream land protection and the blessing of the U.S. Environmental Protection Agency (EPA). But a 1998 legal agreement between the U.S. government, the state of New York, and the city required that supplies from the Croton Watershed be filtered. The filtration plant is being constructed in an excavated site in Van Courtland Park. Once the facility is completed, a golf course driving range will be placed on top.

Built during World War II, the Delaware Aqueduct delivers at least half of New York City’s water supply. A tunneled section of the 137-kilometer (85-mile) conduit has been leaking since at least the 1990s, losing 55,000 to 135,000 cubic meters (15 million to 35 million gallons) per day. The city is preparing to build a five-kilometer (three-mile) bypass around the leak. Construction will begin in 2013.

For the last four decades, deep beneath the city, workers have been drilling a third water-delivery tunnel. New York’s two intra-city tunnels opened in 1917 and 1936, and the newest addition — the largest capital project in the city’s history — will allow the old fleet to be inspected and repaired for the first time in nearly a century.

The Newtown Creek facility in Brooklyn is the largest of the city’s 14 wastewater-treatment plants. It handles 18 percent of the city’s dry weather sewer flows — 1.2 million cubic meters (310 million gallons) per day, serving approximately 1 million people. Renovations at Newtown Creek, which began in 1998, will expand the plant’s peak capacity to 2.6 million cubic meters (700 million gallons) per day during storms, allowing it to serve an additional 300,000 people.

According to an agreement with the EPA, New York City does not have to filter water from the Catskill and Delaware watersheds. In 2002, however, the EPA said that the city would have to disinfect the water, if it wants to keep its filtration waiver. The treatment plant will use ultraviolet light to kill microbial contaminants, such as Cryptosporidium.

Some stormwater systems and sewer systems use the same set of pipes. A combined sewer overflow (CSO) happens when a sudden rush of stormwater exceeds a plant’s capacity, resulting in some flows being dumped untreated into water bodies. The Paerdegat Basin facility will hold up to 190,000 cubic meters (50 million gallons) of water during storms, so that the water can be run through the treatment system when the peak subsidies.

This CSO facility holds up to 160,000 cubic meters (43 million gallons) during storms.