Water Flowing Underground

Plan to store drinking water deep beneath New York City

DANIEL HENDRICK / NY Times 16may04

A PLAN to store drinking water deep beneath New York City has some Long Island residents concerned about the quality of their own supplies.

Later this month, the city's Department of Environmental Protection is expected to seek state approval for a pilot project that could lead to injecting several billion gallons of Catskill Mountain water into groundwater wells in Queens. During times of drought or sudden interruptions of service, including breakdowns or sabotage, the mammoth subterranean reservoir would be tapped to supply the city's eight million residents.

The water would be pumped into, then drawn from, the Lloyd Aquifer, an underground layer of water-bearing sand and gravel that runs under much of the metropolitan region. But some scientists and environmentalists say that mixing the Lloyd's 1,000- to 3,000-year-old water with oxygen-rich, chlorinated and fluoridated surface water could have unintended consequences.

The Lloyd, the deepest of three principal aquifers under Long Island, lies 200 feet beneath the surface on the North Shore and dips to more than 1,500 feet below Fire Island. But because the Lloyd system is so vast - running in a rough crescent shape from Block Island on the north to Florida to the south, to the Delaware and Raritan Rivers in New Jersey on the west and to the continental shelf off Montauk - not all of its dimensions and constituent parts have been mapped, leaving the city to rely on assumptions about how it works.

All of the Island's tap water comes from wells, but most of them are drilled into the shallower Upper Glacial and Magothy aquifers. About 10 percent of Nassau County's water wells tap into the Lloyd. The Long Island American Water company, which serves a quarter of a million people in the southwestern corner of the county, draws from it, as do water districts in Westbury, Manhasset, Port Washington, Locust Valley, Bayville, Great Neck, Mill Neck Estates, Centre Island and Freeport. For Lido Beach, Long Beach and Point Lookout, the sole source of tap water is the Lloyd. Residents are wary of any plan to tinker with it.

"We do not want to give anybody an opportunity, in any way, to contaminate or infiltrate our water," said Assemblyman Harvey Weisenberg, a Long Beach Democrat. "We would like New York City to seek other sources."

Sarah Meyland is a hydrology professor at the New York Institute of Technology in Old Brookville. "Can you physically do it? Yes," she said of the water-stockpiling plan. "Is it the wise thing to do? No. This whole enterprise may look really nice for the city, but it looks really bad for the people of Long Island."

The New York City D.E.P. supplies 1.2 billion gallons of drinking water a day to the city and Westchester, Putnam, Ulster and Orange counties. Ninety-nine percent of the water originates in 19 upstate reservoirs and is transported to the city via three aqueducts. In Queens, 350,000 residents drink a blend of surface and groundwater drawn from 13 wells.

At least a decade ago, New York City learned that its sprawling water supply system had sprung a leak. Engineers estimate that the Delaware Aqueduct, which conveys about a third of the city's water from reservoirs in the Catskills, is hemorrhaging up to 36 million gallons a day - 9 percent of its 400-million-gallon average daily flow - from major leaks at the point where the aqueduct tunnels under the Hudson River. An underwater probe surveyed the aqueduct's interior last year and found scores of cracks. The Hudson Riverkeeper, an environmental group, believes the loss could be as high as 100 million gallons a day.

Engineers are targeting 2012 for a shutdown and repair of the Delaware Aqueduct, which was completed in 1945. Christopher Ward, the city's environmental commissioner, acknowledged last December that the aqueduct cannot be depended on for the long term, increasing speculation that it could collapse one day.

City D.E.P. officials are weighing various contingency plans, including raising the dams on some of the reservoirs in Westchester County, installing bypass tunnels and starting a rebate program to promote sales of water-conserving washing machines. The most promising option, they say, is underground stockpiling, formally known as aquifer storage and recovery.

The technology is well established. David Pyne, author of "Groundwater Recharge and Wells: A Guide to Aquifer Storage Recovery," reports that the first such well (though not into the Lloyd Aquifer) began operating at Wildwood, N.J., in the 1960's, and that there are now more than 70 such systems in use in the United States, Canada, Israel, Australia and South Africa.

New York City's proposal calls for drawing an extra 50 million gallons a day from the existing distribution system and injecting the water into 50 to 100 Queens wells, some new and some that were part of the former Jamaica Water Supply system. After five years, the artificially recharged Lloyd Aquifer could supply up to 200 million gallons a day for two years.

Douglas Greeley, New York City's chief of water and sewer operations, said the project would create a reliable water supply without land acquisition or major infrastructure costs for a relatively inexpensive $600 million to $700 million. "In effect, we would have a very large reservoir underground without having to bulldoze houses or trees and build gatehouses and have it exposed," he said.

The city's plan also promises benefits for Long Island, he said. More than 138 billion gallons a year are drawn from all the aquifers beneath Nassau and Suffolk counties, according to the Farmingdale-based Citizens Environmental Research Institute. Rainfall percolating down through the Island's sandy soil recharges the system, maintaining a balance between fresh water and salt water seeping down from the Atlantic and Long Island Sound. But in dry years, when more fresh water is pumped out than is replaced, the resulting loss of volume and pressure allows the boundary between salt and fresh water to creep landward. Numerous water wells on the Island, especially on the North Shore, have had to be abandoned over the years after they began yielding salt water.

To counter this trend, New York City plans to remove only 90 percent of the water it injects, leaving the remaining 10 percent for recharge. "If we put water in there," Mr. Greeley said, "we'd be pressurizing the water that's in the Lloyd, and we'd be pushing the salt front back, which, one, would benefit the Nassau communities, and two, we'd be restoring a very important natural resource that has been depleted over the years."

From the other side of the Queens-Nassau line, however, things look differently. While pollution on the Island may be the gravest threat to its drinking water, local politicians and civic leaders are likely to take a dim view of any plan to monkey around with the aquifers. "This is our most vital resource," said Frank Ryan, a longtime resident of Point Lookout and president of the local civic association. "Anything that could potentially jeopardize the Lloyd, that's a concern to us."

Many people on the Island say New York City faces an uphill battle selling its proposal to the state's Department of Environmental Conservation. In 1980, the City of Long Beach challenged a Town of Hempstead application to drill into the Lloyd Aquifer to supply the Roosevelt Field shopping mall and the nearby Roosevelt Raceway. The dispute led the state in 1986 to place a moratorium on new tapping of the Lloyd Aquifer by any community for which alternative sources are available. The measure, in effect, put the aquifer off-limits for new drilling by anyone outside coastal areas.

The D.E.C. would need to grant New York City a waiver for the water-stockpiling project to proceed. In March 2004, the department rejected the city's proposal to drill a test well and four observation wells in Queens, because "it was not for any identified coastal community," said a D.E.C. spokeswoman, Maureen Wren.

New York City officials say the applications were rejected largely on technical grounds, and they are continuing to consult with the D.E.C. on a different type of application. Long Beach, meanwhile, is bracing for a fight. "That may mean going to court - we've done it before - if we feel that there are any concerns here, which there very well may be," said Glen Spiritis, the city manager.

The political and legal hurdles are compounded by scientific uncertainties. One of the prime benefits of adding fresh water to the Lloyd, city engineers say, is that saltwater contamination will be displaced offshore and away from drinking wells. But they admit that it will be hard to measure the impact because the precise location of the saltwater-freshwater front in the Lloyd is not known.

The United States Geological Survey, working under a $5 million annual contract with New York City, is using computer models to estimate the aquifer's chemistry at different points, but the model relies on "significant" assumptions, according to a study abstract.

Henry Bokuniewicz, a marine sciences professor at Stony Brook University, said researchers do not yet know enough about the layer of clay that separates the Lloyd from the overlying Magothy and Upper Glacial aquifers, and whether the integrity of this layer, called the Raritan Clay, could be compromised. Clay is impermeable, but it is assumed that there are gaps in the Raritan formation that allow some exchange of water between the Lloyd and Magothy aquifers.

"There are not all that many measurements showing where the gaps are," Dr. Bokuniewicz said. "Those kinds of things plague the predictions." In other words, the Lloyd Aquifer may leak like a sieve, especially when it's under pressure from additional billions of gallons of water being pumped into it. The aquifer may behave like a garden hose with pinhole leaks, able to carry water without significant loss when the sprayer attachment valve is open, but leaking heavily when the sprayer attachment is shut off, raising the pressure inside the hose.

There is also widespread concern about unforeseen chemical reactions when the Lloyd's pristine water meets dissolved nutrients and bacteria in the treated surface water. One possibility is that nitrogen could fuel a growth of bacteria that could clog the wells. Another is that chlorine could react with decaying organic matter to make hazardous substances.

A United States Geological Survey study found that trihalomethanes, which have been linked to cancer, were formed during the course of an aquifer storage program in Lancaster, Calif., in the 1990's. "It's a double-edged sword," said Paul Misut, a U.S.G.S. hydrologist. "The chlorine kills the bacteria and it creates dead bacteria. There's a lot of geochemical processes that happen when two different kinds of water interact."

These are the questions that will be the focus of the demonstration test, according to Don Cohen of Malcolm Pirnie, the lead engineer contractor on New York City's plan. If the D.E.C. gives the green light, about 300 to 400 gallons a day would be injected into the Lloyd Aquifer 900 feet below the surface of Jamaica, Queens, for two weeks. Four observation wells will measure the experiment's progress. If there are no deleterious effects, the pumping would continue for longer intervals, gradually reaching several months at a time. The pilot test would last 14 months.

Mr. Cohen described aquifer storage as a proven technology used in 36 states. He and the city plan to make their case to Long Island elected officials and residents. The federal Environmental Protection Agency is nearing completion of its review of the demonstration, which an E.P.A. spokeswoman, Nina Habib Spencer, described as "low risk." And before any injected water reaches drinking cups, the state's Department of Health must certify its quality.

"We don't want to do something that is going to cause any trouble," Mr. Cohen said. "If the pilot test shows that this is successful, that we can do this, then we would actually think about using an A.S.R. well. If there are problems, we would take that water right out and that would be the end of the program."But Ms. Meyland, the New York Institute of Technology hydrologist, cautioned that the oxygen and fluorides in surface water could do real damage to the Lloyd, even during the small-scale demonstration.

"We don't know what New York City considers to be enough of a problem that they would stop," she said. "In the absence of a full, public discussion of this, with hearings and public input on this, it's entirely inappropriate for the city to go ahead at any stage."

Mr. Misut said the Lloyd could contain 100 trillion gallons of fresh water under Long Island alone. "The Lloyd is really vast," he said. "It has a huge potential for use, and it would be a shame after all this research, given its size, if it didn't get used."

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